- Non-mercury catalytic acetylene hydrochlorination over a NH4F-urea-modified Pd/HY catalyst for vinyl chloride monomer production
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A Pd/HY zeolite catalyst modified with ammonium fluoride and urea (Pd/NH4F-urea-HY) was efficiently applied in an acetylene hydrochlorination reaction. It exhibited an enhanced catalytic performance compared to the untreated Pd/HY catalyst, which was attributed to the presence of ammonium fluoride and urea partly inhibiting carbon deposition and Pd2+ reduction.
- Wang, Lu,Wang, Feng,Wang, Jide
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- High performance of supported Cu-based catalysts modulated via phosphamide coordination in acetylene hydrochlorination
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In order to develop a cut-price, high-efficiency non-mercuric catalyst for acetylene hydrochlorination reaction, several kinds of supported Cu-based catalysts containing phosphoramide ligands have been synthesized by wet impregnation method. The outstanding catalytic activity was obtained over 15 %Cu10 %HMPA/SAC catalyst with acetylene conversion of 87.25 % in the test conditions of T =180 °C, GHSV(C2H2) =180 h?1 and V(HCl): V(C2H2) = 1.2. The catalyst with optimal HMPA ligand also exhibited splendid stability in 100 h lifetime test. The analysis for XRD, TEM, TGA, ICP, H2-TPR and XPS indicated that HMPA ligand can improve Cu species dispersion, restrain coke deposition, suppress loss of loading Cu, and stabilize valence state of active Cu species. Due to electron transfer mechanism, steady coordination structure between Cu and HMPA led to favorable properties of Cu-based catalyst, which was further proved by FT-IR, Raman spectra, O 1s XPS spectra integrated with DFT calculations.
- Hu, Yubing,Wang, Yan,Wang, Yulian,Li, Wei,Zhang, Jinli,Han, You
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- An efficient Au catalyst supported on hollow carbon spheres for acetylene hydrochlorination
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Mesoporous hollow carbon spheres (HCSs) were prepared using SiO2 spheres as a hard template, and Au nanoparticles were then synthesized using NaBH4 as a reducing agent on the surface of the HCS support. Transmission electron microscopy characterization indicated that Au nanoparticles were much smaller on the HCS support than those on the active carbon (AC) support. HCl-TPD showed that the Au/HCS catalyst displayed a more active site than on Au/AC. The resulting Au/HCS catalyst showed excellent catalytic activity and stability for acetylene hydrochlorination. Acetylene conversion of Au/HCS can be maintained above 92% even after 500 h of lifetime. The excellent catalytic performance of Au/HCS was attributed to the presence of the HCS support, which limited the aggregation of Au nanoparticles.
- Kang, Lihua,Zhu, Mingyuan
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- Active carbon supported S-promoted Bi catalysts for acetylene hydrochlorination reaction
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In the present work, the sulfur doped bismuth-based catalysts were prepared by incipient wetness impregnation method and used for the hydrochlorination of acetylene to vinyl chloride monomer (VCM) in a fixed-bed reactor. The effect of introduction of S was characterized by N2 adsorption-desorption, powder X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, temperature-programmed reduction and X-ray photoelectron spectroscopy. The characterization results indicated that the doping of S resulted in the increase of Brunauer-Emmett-Teller (BET) surface areas and decrease of active species particle size for the Bi-based catalysts, which led to more accessible active sites, and consequently boosted the catalytic hydrochlorination activity. The effect of H2SO4 concentration on the activity of this type catalyst was examined, and the results showed that there is an optimal loading of H2SO4 (S/Bi = 0.5 mol/mol), at which the conversion of C2H2 was enhanced to 81% under the reaction condition and coke deposition is a main reason for the deactivation of catalyst.
- Hu, Di,Wang, Lu,Wang, Feng,Wang, Jide
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- Unimolecular HCl elimination from 1,2-dichloroethane: A single pulse shock tube and ab initio study
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Thermal decomposition of 1,2-dichloroethane (1,2-DCE) has been studied in the temperature range of 1050-1175 K behind reflected shock waves in a single pulse shock tube. The unimolecular elimination of HCl is found to be the major channel through which 1,2-DCE decomposes under these conditions. The rate constant for the unimolecular elimination of HCl from 1,2-dichloroethane is found to be 1013.98±0.80 exp(-57.8 ± 2.0/RT) s-1, where the activation energy is given in kcal mol-1 and is very close to that value for CH3CH2Cl (EC). Ab initio (HF and MP2) and DFT calculations have been carried out to find the activation barrier and the structure of the transition state for this reaction channel from both EC and 1,2-DCE. The preexponential factors calculated at various levels of theory (HF/6-311 ++G*, MP2/6-311 ++G*, and B3LYP/6-311 ++G*) are (≈ 1015 s-1) significantly larger than the experimental results. If the torsional mode in the ground state is treated as free internal rotation the preexponential factors reduce significantly, giving excellent agreement with experimental values. The DFT results are in excellent (fortuitous?) agreement with the experimental value for activation energy for 1,2-DCE while the MP2 and HF results seem to overestimate the barrier. However, DFT results for EC is 4.5 kcal mol-1 less than the previously reported experimental values. At all levels, theory predicts an increase in HCl elimination barrier on β-Cl substitution on EC.
- Rajakumar,Reddy,Arunan
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- Hydrochlorination of acetylene using expanded multilayered vermiculite (EML-VMT)-supported catalysts
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Catalyst supports have very important effects on catalyst performance. A novel expanded multilayered vermiculite (EML-VMT) is successfully used as the catalyst support for the acetylene hydrochlorination. By mixing carbon on the surface of EML-VMT (i.e., EML-VMT-C), the HgCl2/EML-VMT-C achieved a high acetylene conversion of 97.3%, a vinyl chloride selectivity of 100% and a turn over frequency (TOF) value 8.83*10-3s-1 a temperature of 140 8C, an acetylene gas hourly space velocity (GHSV) of 108 h-1, and a feed volume ratio V(HCl)/V(C2H2) of 1.15. Moreover, the HgCl2/EML-VMT-C shows good stability. The EML-VMT also shows potential in the preparation of other EML-VMT-supported catalysts.
- Xin-Huang,Yu, Feng,Zhu, Ming-Yuan,Ouyang, Fei-Hong,Dai, Bin,Dan, Jian-Ming
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- Kinetics of acetylene hydrochlorination over bimetallic Au-Cu/C catalyst
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A kinetic model of the acetylene hydrochlorination over the bimetallic Au-Cu/C catalyst was obtained on the basis of kinetic data. DFT theoretical calculation and the kinetic model indicated the reaction probably proceeds via the Eley-Rideal mechanism in which gas phase HCl reacts with the adsorbed C 2H2 to produce vinyl chloride. Reaction conditions were optimized according to kinetics analyses. Under the optimized reaction conditions obtained, the bimetallic Au-Cu/C showed excellent performances with more than 99.5% conversion and selectivity and did not deactivate in 200 h on stream.
- Wang, Shengjie,Shen, Benxian,Song, Qinglei
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- An Au-Cu bimetal catalyst for acetylene hydrochlorination with renewable γ-Al2O3 as the support
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The bimetal catalyst gold(iii) chloride-copper(ii) chloride (AuCl3-CuCl2) was prepared with several different gamma-aluminium oxide (γ-Al2O3) supports and its catalytic properties towards acetylene hydrochlorination were assessed in a fixed-bed reactor. The comparison indicated that one of the catalysts attained the highest activity with an acetylene conversion of 97%, which was far higher than the others. Catalysts were characterized using detailed X-ray diffraction, nitrogen-Brunauer, Emmett and Teller surface area analysis (N2-BET), ammonia temperature-programmed desorption, Fourier-transform infrared spectroscopy and carbon dioxide temperature-programmed desorption analysis. It is proposed that the base site contributed to its high catalyst activity compared with the other catalysts, instead of the acid site or the textural properties on the support, therefore, the activity and the life of the catalysts can be improved significantly by treating the supports with potassium hydroxide. In addition, the results of N2-BET, thermogravimetric analysis and scanning electron microscopy indicated that the catalysts deactivated rapidly because of carbon deposition, and the actual amount of coke deposition was 18.0% after the reaction. AuCl3-CuCl2/γ-Al2O3 was easily regenerated for reuse as a catalyst by burning off in an air atmosphere for 10 min. The activity of the regenerated catalyst nearly reached the level of the fresh catalyst. This journal is
- Zhao, Jigang,Zeng, Junjian,Cheng, Xiaoguang,Wang, Lei,Yang, Henghua,Shen, Benxian
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- Chlorocuprate(i) ionic liquid as an efficient and stable Cu-based catalyst for hydrochlorination of acetylene
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The gas-liquid reaction process for acetylene hydrochlorination, especially using ionic liquids (ILs) as homogeneous reaction media, has gained much attention because it can effectively avoid the deactivation caused by hot spots and carbon deposition. However, the relatively low activity and high price of the currently used ILs limit their practical applications. Herein, we synthesize a series of chlorocuprate(i) ILs to explore an efficient and stable Cu-based catalyst for acetylene hydrochlorination. The N-methylpyrrolidonium hydrochloride-0.60CuCl ([Hnmpo]Cl-0.60CuCl) IL exhibits the best catalytic performance, showing an acetylene conversion of 86% over 150 h under the conditions of 180 °C and 50 h-1 GHSV. It is confirmed that the Cu(i) species is the major active component and extremely stable under the reaction conditions via characterization of TGA-DSC-FTIR, ICP-OES, XPS, UV-vis, ESI-MS, and Raman. In addition, the [Hnmpo]Cl-0.60CuCl IL has the capacity to effectively activate HCl, which is directly observed by in situ FTIR. By combining the experimental results and theoretical calculations, we propose the reaction mechanism and find that the catalytic performance of chlorocuprate(i) ILs is positively correlated with the adsorption of HCl. The strong interaction with HCl is identified as the key characteristic of the [Hnmpo]Cl-CuCl IL, which endows it with excellent catalytic performance. Briefly, this study shows that the cost-effective [Hnmpo]Cl-CuCl IL can be a viable alternative to the commercial heterogeneous HgCl2/AC catalyst for acetylene hydrochlorination.
- Ren, Yanfei,Wu, Botao,Wang, Fumin,Li, Hang,Lv, Guojun,Sun, Mingshuai,Zhang, Xubin
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- Novel nonmetal catalyst of supported tetraphenylphosphonium bromide for acetylene hydrochlorination
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Tetraphenylphosphonium bromide (TPPB) ionic liquid-supported catalysts were synthesized and evaluated for the acetylene hydrochlorination reaction for the development of highly efficient nonmetal catalysts as substitutes for the currently used industrial mercuric catalyst in the production of vinyl chloride (VCM). The optimal 15% TPPB/SAC catalyst exhibited favorable catalytic activity and stability, with the highest acetylene conversion of 97.1% and the selectivity for VCM above 99.5% under the conditions of 220 °C, an acetylene gas hourly space velocity (GHSV) = 30 h-1 and VHCl/VC2H2 = 1.15. Characterized by TPD, FTIR, XPS, etc., TPPB exhibits strong adsorption toward HCl but very weak adsorption toward C2H2 and VCM; in particular, the adsorbed HCl can change the conformational structure of TPPB. DFT calculations suggest that over the active catalytic site of TPPB, the activation energy of acetylene hydrochlorination is 21.15 kcal mol-1, which is much lower than that without catalyst (44.29 kcal mol-1). During the reaction, the H-Cl bond is preferentially activated through accepting the electrons transferred from the anion of TPPB, and then the C2H2 is activated to complete the addition reaction of H and Cl. Such unique preferential activation toward the H-Cl bond as well as the weak adsorption to the product VCM promotes the catalytic activity and the stability of the supported TPPB catalysts. The amount of carbon deposition on the 15% TPPB/SAC catalyst is as low as 2.99%, even after 300 h of reaction. The high activity and stability of the 15% TPPB/SAC catalyst indicate great promise for its application as a nonmetal catalyst for acetylene hydrochlorination.
- Li, Xiaoyan,Nian, Yao,Shang, Shanshan,Zhang, Haiyang,Zhang, Jinli,Han, You,Li, Wei
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- Non-mercury catalytic acetylene hydrochlorination over bimetallic Au-Co(III)/SAC catalysts for vinyl chloride monomer production
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Several gold-based catalysts including Au, Au-La(iii), Au-Co(ii), and Au-Co(iii) were prepared and assessed for acetylene hydrochlorination, combining with characterizations of low-temperature N2 adsorption/desorption, thermogravimetric analysis, X-ray diffraction, temperature-programmed reduction, inductively coupled plasma-atomic emission spectroscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. The best catalytic performance was obtained over Au1Co(iii)3/SAC catalysts with an acetylene conversion of 92% and a selectivity to VCM of 99.9%. It is indicated that the additives of Co(iii), Co(ii) and La(iii) are preferential to stabilize the catalytic active Au+ species and inhibit the reduction of Au3+ to Au 0 in the preparation process of Au-based/SAC catalysts. The addition of these additives can greatly inhibit the occurrence of coke deposition on the catalyst surface, and also inhibit the catalyst sintering, thereby improving the activity and long-term stability of the Au-based catalysts.
- Zhang, Haiyang,Dai, Bin,Wang, Xugen,Li, Wei,Han, You,Gu, Junjie,Zhang, Jinli
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- Continuous-wave CO2 Lase-induced Chain Reaction of 1,2-Dichloroethane
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The chain reaction of 1,2-dichloroethane induced by a CW CO2 laser has been studied in the presence of SF6 as a sensitizer.Vinyl chloride and hydrogen chloride are the main products.The photosensitized decomposition of 1,2-dichloroethane mainly depends on the irradiated laser frequency and is governed by the excitation of the vibrational mode and collisional energy transfer.Arrhenius plots show two distinct regimes, corresponding to the respective activation energies: 96.3 kJ mol-1 for the low-temperature regime and 50.2 kJ mol-1 for the high-temperature regime.The inhibiting and promoting effects of the propene and chlorine, respectively, on the chain reaction are examined.The kinetics proposed for the chain reaction are in agreement with the observed data, and mechanisms for molecular excitation and intramolecular energy transfer have been discussed.By using an IR lase, active centres can be generated, and initiation and propagation of a chain reaction at lower temperatures than is possible thermally can be achieved.This may be a way to decrease the energy expenditure and reduce the number of by-products in the chain reaction.
- Ma, Pelhua,Liu, Julin,Chen, Guancheng,Chu, Minxiong,Jing, Yan,Wu, Bin
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- Acetylene catalytic hydrochlorination over mechanically pre-activated K2PdCl4 salt: A study of the reaction mechanism
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Mechanical pre-grinding of solid K2PdCl4 in a vibratory micromill under acetylene or propylene atmosphere leads to the formation of catalyst for acetylene hydrochlorination by gaseous HCl. The active sites of the heterogeneous catalyst are Pd(II) chloro complexes with a coordination vacancy, capable reversibly form π-acetylene complexes. The HCl molecules participate in two steps of the reaction: acetylene chloropalladation (rate-limiting step) forming intermediate σ-chlorovinyl Pd(II) derivative and protonolysis of the last one.
- Krasnyakova, Tatyana V.,Zhikharev, Igor V.,Mitchenko, Regina S.,Burkhovetski, Valeriy I.,Korduban, Alexander M.,Kryshchuk, Taras V.,Mitchenko, Serge A.
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- In situ K-edge X-ray absorption spectroscopy of the ligand environment of single-site Au/C catalysts during acetylene hydrochlorination
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The replacement of HgCl2/C with Au/C as a catalyst for acetylene hydrochlorination represents a significant reduction in the environmental impact of this industrial process. Under reaction conditions atomically dispersed cationic Au species are the catalytic active site, representing a large-scale application of heterogeneous single-site catalysts. While the metal nuclearity and oxidation state under operating conditions has been investigated in catalysts prepared from aqua regia and thiosulphate, limited studies have focused on the ligand environment surrounding the metal centre. We now report K-edge soft X-ray absorption spectroscopy of the Cl and S ligand species used to stabilise these isolated cationic Au centres in the harsh reaction conditions. We demonstrate the presence of three distinct Cl species in the materials; inorganic Cl-, Au-Cl, and C-Cl and how these species evolve during reaction. Direct evidence of Au-S interactions is confirmed in catalysts prepared using thiosulfate precursors which show high stability towards reduction to inactive metal nanoparticles. This stability was clear during gas switching experiments, where exposure to C2H2 alone did not dramatically alter the Au electronic structure and consequently did not deactivate the thiosulfate catalyst.
- Aramini, Matteo,Freakley, Simon J.,Gianolio, Diego,Gibson, Emma K.,Hutchings, Graham J.,Johnston, Peter,Kondrat, Simon A.,Malta, Grazia,Morgan, David J.,Thompson, Paul B. J.,Wells, Peter P.
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- Catalytic Dehydrochlorination of 1,2-Dichloroethane into Vinyl Chloride over Polyacrylonitrile-Based Active Carbon Fiber (PAN-ACF)
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A PAN-ACF with large surface area was found to enhance dehydrochlorination of 1,2-dichloroethane into vinylchloride in selectivity above 99percent at a conversion level of 21 to 63percent in the temperature range of 300-350 deg C.The ACF showed stable activity at 325 deg C for 100 h.In contrast, other carbon materials were found to show either low activity or short life, although their selectivities were fairly high.
- Mochida, Isao,Yasumoto, Yoshinori,Watanabe, Yoshiro,Fujitsu, Hiroshi,Kojima, Yasuhiro,Morita, Makoto
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- Wheat flour-derived N-doped mesoporous carbon extrudate as superior metal-free catalysts for acetylene hydrochlorination
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N-Doped mesoporous carbon extrudate with a major quaternary N species has been successfully prepared through direct carbonization of wheat flour/gluten with silica, which is a cheap and convenient method for scale-up production approach. The obtained carbon extrudate metal-free catalyst enables highly efficient production of vinyl chloride monomer through acetylene hydrochlorination, with a superior catalytic performance and excellent stability (>85% conversion and vinyl chloride selectivity over 99% at 220 °C).
- Lan, Guojun,Wang, Yan,Qiu, Yiyang,Wang, Xiaolong,Liang, Ji,Han, Wenfeng,Tang, Haodong,Liu, Huazhang,Liu, Jian,Li, Ying
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- Acetylene hydrochlorination over supported ionic liquid phase (SILP) gold-based catalyst: Stabilization of cationic Au species via chemical activation of hydrogen chloride and corresponding mechanisms
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The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination. Here, we report a strategy for activating HCl by the Au-based supported ionic liquid phase (Au–SILP) technology with the [N(CN)2?] anion. This strategy enables HCl to accept electrons from [N(CN)2?] anions in Au–[N(CN)2?] complexes rather than from pure [Bmim][N(CN)2], leading to notable improvement in both the reaction path and the stability of the catalyst without changing the reaction triggered by acetylene adsorption. Furthermore, the induction period of the Au–SILP catalyst was shown to be absent in the reaction process due to the high Au(III) content in the Au(III)/Au(I) site and the high substrate diffusion rate in the ionic liquid layer. This work provides a facile method to improve the stability of Au-based catalysts for acetylene hydrochlorination.
- Fang, Zheng,Feng, Feng,Guo, Lingling,Jin, Chunxiao,Li, Xiaonian,Lu, Jinyue,Pan, Zhiyan,Pang, Xiangxue,Wang, Bolin,Wang, Saisai,Yue, Yuxue,Zhao, Jia
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- Catalytic dehydrochlorination of 1,2-dichloroethane to produce vinyl chloride over N-doped coconut activated carbon
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A series of N-doped coconut activated carbon catalysts (N-AC) were prepared using melamine as the nitrogen precursor and their performance for the catalytic dehydrochlorination of 1,2-dichloroethane (1,2-DCE) to produce vinyl chloride monomer (VCM) was assessed. It is indicated that the N-doped catalyst 5 : 10-N-AC exhibits a stable catalytic activity at 250 °C with the 1,2-DCE conversion of 85.1% at 180 h. Through DFT calculations, it is suggested that both pyridinic and pyrrolic nitrogen dopants can adsorb preferentially 1,2-DCE and increase the activity for 1,2-DCE dehydrochlorination at low temperature, in combination with characterizations of BET, Raman, TG, TPD, XPS, etc. In addition, the increase of quaternary nitrogen dopants and coking deposition on the catalyst surface can result in the activity decline. The N-doped activated carbon catalyst provides a promising pathway to produce VCM through a low-temperature energy-saving process of 1,2-DCE catalytic dehydrochlorination.
- Zhao, Wei,Sun, Mengxia,Zhang, Haiyang,Dong, Yanzhao,Li, Xiaoyan,Li, Wei,Zhang, Jinli
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p. 104071 - 104078
(2015)
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- Synthesis and characteristics of organotin-based catalysts for acetylene hydrochlorination
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Organotin-based catalysts prepared by a facile and green synthesis route were used in the acetylene hydrochlorination reaction. In detail, organotin-based catalysts were directly synthesized by supporting both organotin and nitrogen compounds on a coal-based columnar activated carbon (AC) using both incipient wetness impregnation and calcination methods. Interestingly, upon addition of nitrogen compounds, the resultant (SnCl4 + C16H34Cl2Sn)/AC catalysts showed higher activity and stability when compared the its (SnCl4 + C16H34Cl2Sn + C2N4H4)/AC counterpart at 200 °C and a gas hourly space velocity (GHSV, C2H2 based) of 30 h1. According to the results, organotin was demonstrated to be the active site, whereas the incorporation of nitrogen allowed partial mitigation of the loss of active components.
- Wu, Yi-Bo,Li, Bo-Wen,Li, Fu-Xiang,Xue, Jian-Wei,Lv, Zhi-Ping
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- Non-mercury catalytic acetylene hydrochlorination over Ru catalysts enhanced by carbon nanotubes
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Ru-based catalysts with different deposition sites were prepared using multiwalled carbon nanotubes as the support and RuCl3 as the precursor, to study the effects of multiwalled carbon nanotubes on the catalytic performance of Ru catalysts for acetylene hydrochlorination. It has been suggested that Ru catalysts deposited inside the CNTs channels exhibit the optimal catalytic activity with the acetylene conversion of 95.0% and the selectivity to VCM of 99.9% after 10 h on stream under the conditions of 170 °C and GHSV (C2H2) of 90 h-1. In combination with characterizations of BET, TEM, XRD, TPR, TPD and XPS, it is illustrated that the CNTs with the inner diameter about 3-7 nm can functionalize as an efficient support with unique electron property to enhance the catalytic performance of Ru-based catalysts for acetylene hydrochlorination.
- Li, Guangbi,Li, Wei,Zhang, Haiyang,Pu, Yanfeng,Sun, Mengxia,Zhang, Jinli
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- Kinetics of the Reaction of Chlorine Atoms with Vinyl Bromide and Its Use for Measuring Chlorine-Atom Concentrations
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The reaction of chlorine atoms with vinyl bromide, Cl + C2H3Br = C2H3Cl + Br, has been tested as a titration reaction for chlorine atoms in gas-phase fast-flow reactors using both continuous and pulsed atom sources.The vinyl chloride produced by this reaction was determined by using photoionization mass spectrometry and was found to be an accurate measure of the in situ chlorine-atom concentration down to 5 * 1010 atoms cm-3.The reaction is rapid and stoichiometric and involves the use of easily handled substances.It is particularly well suited for use with photoionization mass spectrometer detectors because of the low ionizaton potentials and high photoionization cross sections of both vinyl bromide and vinyl chloride.The rate constant of this reaction was measured at 298 K and determined to be 1.43 (+/- 0.29) * 10-10 cm3 molecule-1 s-1.
- Park, Jong-Yoon,Slagle, Irene R.,Gutman, David
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- Promotional effect of copper(ii) on an activated carbon supported low content bimetallic gold-cesium(i) catalyst in acetylene hydrochlorination
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The synthesis of a vinyl chloride monomer (VCM) from acetylene hydrochlorination is a highly attractive coal-based route using mercury chloride (HgCl2) as the catalyst. On reducing the use of mercury and with increasing concerns about environmental issues, searching for alternative catalysts has gained interest in recent years. However, to achieve high yield and stability using a mercury-free catalyst in this reaction is a substantial challenge. We approach this question by probing a Cu-added AuCs/AC catalyst working as a highly active, stable and cost-effective catalyst for this reaction. Introducing Cu into the catalyst significantly increased the activity and stability compared to a bicomponent AuCs/AC catalyst, underscoring a remarkable synergistic effect of the three metals. The particularly remarkable enhancement of activity was observed for the catalyst with a Au/Cu/Cs weight ratio of 1: 1: 4 (Au = 0.25 wt%), which provided a high turnover frequency of 73.8 min-1 based on Au. Further experiments showed that the AuCuCs/AC catalyst delivered a stable performance during a 600 h test with the conversion of acetylene maintaining more than 98.8% at a C2H2 gas hourly space velocity of 50 h-1 and the estimated lifetime exceeding 6540 h. After a careful characterization of the AuCuCs/AC catalyst and additional catalytic tests, we concluded that the observed enhanced catalytic performance could be associated with the enhanced dispersion of Au particles, the stabilization of Au in the state of Au3+ and facile substrate C2H2 molecule desorption. Compared with the commercial high content HgCl2 catalyst (Hg = 12 wt%), this low content AuCuCs/AC catalyst (Au = 0.25 wt%) has similar activity, higher stability, relative low cost and environmental friendliness, meaning it has potential as an alternative to the HgCl2 catalyst for commercial production of VCM.
- Zhao, Jia,Gu, Shanchuan,Xu, Xiaolong,Zhang, Tongtong,Di, Xiaoxia,Pan, Zhiyan,Li, Xiaonian
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p. 101427 - 101436
(2015)
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- Modifications of the metal and support during the deactivation and regeneration of Au/C catalysts for the hydrochlorination of acetylene
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The effect of the gold oxidation state and carbon structure on the activity of Au/C catalysts for the hydrochlorination of acetylene was investigated by a combined approach using TPR, XPS and porosimetry determinations. The activity of the catalyst in the synthesis of vinyl chloride monomer was found to be dependent on the presence of Au3+ species in the catalyst. However, by preparing catalysts with different Au3+ content it was possible to determine the existence of a threshold Au3+ amount, beyond which the excess of Au3+ was not active for the reaction. This was explained by the existence of active sites at the Au/C interface, and not just by the presence of Au3+ species on top of Au nanoparticles, as explained by current models for these catalysts. It was also possible to determine the existence of a subset of Au nanoclusters which do not take part in the reaction, as well as changes in the textural properties of the carbon that can affect its long term reusability. The Royal Society of Chemistry 2013.
- Conte, Marco,Davies, Catherine J.,Morgan, David J.,Davies, Thomas E.,Carley, Albert F.,Johnston, Peter,Hutchings, Graham J.
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- Effects of nitrogen-dopants on Ru-supported catalysts for acetylene hydrochlorination
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A series of N-doped spherical active carbons were synthesized via the pyrolysis of melamine in activated carbon, and used as a support to prepare Ru-based catalysts for an acetylene hydrochlorination reaction. The catalytic performance assessments indicate that the N-doped carbon support can increase greatly the activity and the stability of Ru-based catalysts. The optimal activity is achieved over Ru/SAC-N700, with an acetylene conversion of 99.8% under the conditions of 170°C, C2H2 gas hour space velocity (GHSV) of 180 h-1, a feed volume ratio of V(HCl)/V(C2H2) of 1.1 after 30 h. Using characterizations of BET, FT-IR, XPS, TPR, TPD, TG, etc., it is illustrated that N-dopants can increase the dispersion of Ru elements, enhance the adsorption of reactants and the desorption of the product, and reduce significantly the coke deposition, consequently resulting in higher catalytic activity of Ru/SAC-N700. It is suggested that the pyridine-nitrogen plays an important role in augmenting the catalytic activity of Ru-supported catalysts.
- Hou, Lijun,Zhang, Jinli,Pu, Yanfeng,Li, Wei
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- Elementary Processes in the Gas-Phase Photodecomposition of Singlet and Triplet 3-Chloro-3-methyldiazirine
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3-Chloro-3-methyldiazirine has been photolyzed in the gas phase at 416, 365, and 337 nm.With these wavelengths, 3n?* and 1n?* states could be prepared, the last one with different amounts of rovibrational energy.The elementary processes occurring after the optical excitation have been analyzed with the help of algorithms recently devloped.The triplet leads to "hot" vinyl chloride through the intermediacy af a diradical.In the case of the singlet, two competitive pathways take place.The first one switches to the triplet route after the initial excited diazirine undergoes an intersystem crossing process.The second one produces the "hot" vinyl chloride through adiabatic isomerization of the diazirine to the isomeric diazo compound.In both routes, the intermediate diradical and diazo compound decompose to singlet chloromethylcarbenes differing only in their rotovibrational energy content.Subsequent 1,2-hydrogen shift gives rise to the final vinyl chlorides containing different amounts of internal energy.The reaction mechanism put forward agrees with all the data known to date about this photodecomposition.We should emphasize that the purpose of this work was the study of the unimolecular processes occuring in the photodissociation.Minor subsequent or parallel bimolecular reactions possibly occurring (formation of dichloroethanes, for example) have been purposely excluded.However, some quenching experiments have been used as probes of the reaction mechanism.
- Avila, Maria J.,Becerra, Rosa,Figuera, Juan M.,Rodriguez, Juan C.,Tobar, Aurora,Martinez-Utrilla, Roberto
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- Boron and Nitrogen Doping in Graphene for the Catalysis of Acetylene Hydrochlorination
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Exploration of environmentally friendly catalysts is important for acetylene hydrochlorination because the traditional HgCl2 catalyst is highly toxic and harmful to human health. Herein, boron and nitrogen heteroatoms dually doped on oxide graphene (B,N-G) catalyst were synthesized using a model calcination method and applied as a nonmetallic catalyst for acetylene hydrochlorination. The B,N-G catalyst shows acetylene conversion significantly higher (nearly 95%) than that of singly B- or N-doped graphenes and a little lower than that of Au and Hg catalyst. Density functional theory calculations and temperature-programmed desorption results indicate that the synthetic effect of B and N doping can promote HCl adsorption, which is the rate-determining step in acetylene hydrochlorination. The excellent catalytic efficiency and relatively low cost of B,N-G makes it a promising catalyst for acetylene hydrochlorination.
- Dai, Bin,Chen, Kun,Wang, Yang,Kang, Lihua,Zhu, Mingyuan
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- Towards a greener approach for the preparation of highly active gold/carbon catalyst for the hydrochlorination of ethyne
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Gold on activated carbon (Au/AC) materials are promising alternative catalysts for ethyne hydrochlorination. The preparation of active, stable Au/AC catalysts without aqua regia for ethyne hydrochlorination remains a significant challenge. A novel catalyst preparation protocol involving impregnation using a H2O2/HCl mixture is established for highly active Au/AC catalysts comprising primarily of single-site cationic Au species, as identified by systematic X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR) analyses and transmission electron microscopy (TEM) imaging. In addition, evaluation of the Au-C interface by temperature-programmed desorption (TPD) analyses showed that the oxidation of activated carbon by the H2O2/HCl mixture, which creates surface oxygen-containing functional groups (SOGs), is a crucial step for the formation of active Au/AC catalysts. The structure determination and comprehensive experimental evidence allow density functional theory (DFT) to predict that single-site cationic AuCl species stabilized by SOGs via -O- linkages are efficient active sites for Au-catalyzed ethyne hydrochlorination. In addition, these catalysts can be reused for several times with negligible changes in performance after treatment with the H2O2/HCl mixture. The H2O2/HCl mixture is thus envisioned as a viable, green alternative to toxic aqua regia for the preparation of Au/AC catalysts for ethyne hydrochlorination.
- Zhao, Jia,Wang, Bolin,Yue, Yuxue,Di, Shuxia,Zhai, Yuanyuan,He, Haihua,Sheng, Gangfeng,Lai, Huixia,Zhu, Yihan,Guo, Lingling,Li, Xiaonian
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- Preparation of Au/C catalysts using microwave-assisted and ultrasonic-assisted methods for acetylene hydrochlorination
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In the present work, the catalytic performance of Au/C catalysts prepared by ultrasonic-assisted, microwave-assisted and incipient wetness impregnation techniques for the hydrochlorination of acetylene to vinyl chloride monomer (VCM) was studied. The catalyst prepared by the ultrasonic-assisted technique significantly exhibited enhanced acetylene conversion activity and selectivity to VCM over a period of 20 h of evaluation. The effect of gold loading on catalyst performance was determined, from which 1% Au was found to be the optimum loading compared to 0.5% and 2.0% loading. Importantly, the effect of different catalyst pretreatments (i.e. with and without H2/HCl and HCl purging prior to the reaction testing) on the catalytic performance was also identified. The use of different pretreatment procedures affects only the initial activity of catalyst, while the long-term activities of catalyst with different pretreatments are almost identical.
- Wittanadecha,Laosiripojana,Ketcong,Ningnuek,Praserthdam,Monnier,Assabumrungrat
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- Catalytic performance of AuIII supported on SiO2 modified activated carbon
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Silica was deposited onto activated carbon through TEOS hydrolysis and this composite was used as a support for the Au catalyst in acetylene hydrochlorination. Silica content and the catalyst synthesis process were both optimized. It was found that 1Au/5SiO2/AC showed improved stability, while being as active as 1Au/AC. Thermogravimetric analysis (TGA) quantitatively revealed the synchronism of TEOS hydrolysis and Au deposition, which was believed to be the linchpin in 1Au/5SiO2/AC synthesis. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) demonstrated that amorphous silica dispersed on the carbon surface uniformly as spherical particles. Silica deposition brought down the surface area of the catalyst while leading to better distribution of gold nanoparticles. Higher gold distribution degree guaranteed the catalytic activity of 1Au/5SiO2/AC despite surface area loss. A higher level of resistance to acetylene, excellent surface property stability and less carbonaceous deposition were determined as the origin of the improved stability of 1Au/5SiO2/AC. This journal is the Partner Organisations 2014.
- Tian, Xiaohui,Hong, Guotai,Liu, Ying,Jiang, Binbo,Yang, Yongrong
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- Study of the active site for acetylene hydrochlorination in AuCl3/C catalysts
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AuCl3/C catalysts were prepared using activated carbon pretreated at different temperatures. The set of catalysts was evaluated for acetylene hydrochlorination, and the most stable catalyst exhibited the weakest acetylene adsorption capacity, as characterized by the method of temperature-programmed desorption (TPD). The catalysts were also investigated using X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and other methods. It is shown that the activated carbon works as a constituent part of the active site that is responsible for the activation of acetylene. The result provides evidence for the assumption that the Au3+ at the AuCl3/C interface of the catalyst is the active site of the classical AuCl3/C catalyst.
- Chao, Songlin,Guan, Qingxin,Li, Wei
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- Reactivity enhancement of N-CNTs in green catalysis of C2H 2 hydrochlorination by a Cu catalyst
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We reported the prominent effect of nitrogen-doped carbon nanotubes (N-CNTs) on reactivity enhancement in catalyzing acetylene hydrochlorination, which improved the TOF of Cu to ca. 1.2 min-1, proving that N-CNTs is a potential green substrate, and that the Cu-based catalyst is an alternative to the toxic conventional HgCl2 catalyst.
- Zhou, Kai,Si, Jiangkun,Jia, Jinchao,Huang, Jiaqi,Zhou, Jun,Luo, Guohua,Wei, Fei
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- Acetylene hydrochlorination over boron-doped Pd/HY zeolite catalysts
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A novel boron-doped Pd/HY zeolite catalyst for acetylene hydrochlorination was prepared and exhibited an outstanding catalytic performance (the acetylene conversion was maintained at >95% for about 30 h). The boron species can stabilize catalytically active Pd2+ species and weaken carbon deposition and Pd2+ reduction during the reaction, thus improving the catalytic stability.
- Wang, Lu,Lian, Lizhen,Yan, Haijun,Wang, Feng,Wang, Jide,Yang, Chao,Ma, Lida
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- Kinetics of the Reactions of Silicon Compounds. Part 10. Kinetics and Mechanism of the Gas-phase Thermal Reactions of Trichloro-(1,1-difluoroethyl)silane. An Intramolecular Halogen Exchange Reaction
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The gas-phase thermal isomerisation of trichloro-(1,1-difluoroethyl)silane (I) to chloro-(1,1-dichloroethyl)difluorosilane (II) is a first-order homogeneous process at 375-416 K and 11-67 mmHg initial pressure.The reaction is unaffected by the presence of the radical inhibitors 2,3-dimethylbut-2-ene and nitric oxide, and it is concluded that the rate-determining step is a unimolecular isomerisation of (I) to dichloro-(1-chloro-1-fluoroethyl)fluorosilane (III), which then undergoes a secondary fast isomerisation to the observed product (II).The log10k1/s-1 = (13.38 +/- 0.05) - (127.2 +/- 0.4) kJ mol -1/RT ln 10 data suggest a transition state in which the fluorine atom transfer is more advanced than the chlorine atom transfer.The minor products vinyl chloride and dichlorodifluorosilane are shown to arise from thermal and chemically activated decomposition of the initially formed (II) and/or (III).
- Baker, Richard H.,Haszeldine, Robert N.,Robinson, Peter J.
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- Sustainable Synthesis of Bimetallic Single Atom Gold-Based Catalysts with Enhanced Durability in Acetylene Hydrochlorination
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Gold single-atom catalysts (SACs) exhibit outstanding reactivity in acetylene hydrochlorination to vinyl chloride, but their practical applicability is compromised by current synthesis protocols, using aqua regia as chlorine-based dispersing agent, and their high susceptibility to sintering on non-functionalized carbon supports at >500 K and/or under reaction conditions. Herein, a sustainable synthesis route to carbon-supported gold nanostructures in bimetallic catalysts is developed by employing salts as alternative chlorine source, allowing for tailored gold dispersion, ultimately reaching atomic level when using H2PtCl6. To rationalize these observations, several synthesis parameters (i.e., pH, Cl-content) as well as the choice of metal chlorides are evaluated, hinting at the key role of platinum in promoting a chlorine-mediated dispersion mechanism. This can be further extrapolated to redisperse large gold agglomerates (>70?nm) on carbon carriers into isolated atoms, which has important implications for catalyst regeneration. Another key role of platinum single atoms is to inhibit the sintering of their spatially isolated gold-based analogs up to 800 K and during acetylene hydrochlorination, without compromising the intrinsic activity of Au(I)-Cl active sites. Accordingly, exploiting cooperativity effects of a second metal is a promising strategy towards practical applicability of gold SACs, opening up exciting opportunities for multifunctional single-atom catalysis.
- Kaiser, Selina K.,Clark, Adam H.,Cartocci, Lucrezia,Krumeich, Frank,Pérez-Ramírez, Javier
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- Nitrogen-doped pitch-based spherical active carbon as a nonmetal catalyst for acetylene hydrochlorination
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A highly active nitrogen-doped pitch-based spherical activated carbon catalyst (PSAC-N) is synthesized through a nitrogen-doping treatment and used as a nonmetal catalyst for acetylene hydrochlorination. The conversion of acetylene on PSAC-N exceeds 68% and the selectivity of vinyl chloride is over 99% at a temperature of 250°C, an acetylene gas hourly space velocity of 120 h-1, and a feed volume ratio V(HCl)/V(C2H2) of 1.15. DFT calculations performed with Gaussian 09 program package reveal that the active site of PSAC-N has a N-6v (quaternary nitrogen bonded between two 6-membered rings) structure. A seven benzene ring unit model is used in the DFT study. In addition, the reason for inactivation for PSAC-N catalysts is discussed. Of all the adsorption energies obtained, the adsorption capacity of hydrogen chloride on PSAC-N is the highest, which indicates strong ability for acetylene hydrochlorination. The reaction mechanism is determined, and the reaction energy of N-6v(7) calculated as 236.2 kJmol-1.
- Wang, Xugen,Dai, Bin,Wang, Yang,Yu, Feng
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- Catalytic properties of Pd/HY catalysts modified with NH4F for acetylene hydrochlorination
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Ammonium fluoride (NH4F) modified HY zeolite catalysts were prepared by ultrasonic-assisted impregnation and their efficient catalytic behavior in acetylene hydrochlorination reaction was investigated (the conversion of acetylene and the selectivity to vinyl chloride were all achieved above 99%). The results indicate that the presence of NH4F in Pd/HY catalysts can partially enhance the surface acidity of catalysts, and weaken the occurrence of carbon deposition and the loss of Pd active component on the catalyst surface, thus improving the catalytic performance of catalysts.
- Wang, Lu,Wang, Feng,Wang, Jide
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- Enhanced activity of hydrochlorination of acetylene using melamine-modified activated carbon supported gold catalyst
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A series of modified activated carbon (MAC) was prepared by impregnating with a aqueous solution of melamine and heating under N2 flow at diffferent temperatures. The surface structure of the prepared MAC was characterized by BET, elemental analysis, SEM, FT-IR and XPS. The results of the single carrier activity test showed that MAC exhibited higher activity than activated carbon. Characterization results indicated that the enhanced carrier performance of MAC could be attributed to the presence of nitrogen-containing groups. Subsequently, the supported gold catalysts Au/activated carbon and Au/MAC-0.8-650 were prepared by impregnating with a H[AuCl4] 4H2O solution which was dissolved in aqua regia. Under the reaction conditions of feed volume ratio V (HCl)/V (C2H2) = 1.15, temperature 180 C, C2H2 hourly space velocity (GHSV) 360 h-1 and gold loading of 0.2 wt %, the acetylene conversion and vinyl chloride monomer selectivity of Au/MAC-0.8-650 were 95 and > 99.91 %.
- Dai, Bin,Ma, Ning,Zhang, Haiyang,Wang, Xugen
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- Nitrogen functional groups on an activated carbon surface to effect the ruthenium catalysts in acetylene hydrochlorination
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To improve the activity and stability of Ru-based catalysts with a carbon support for acetylene hydrochlorination, activated carbon (AC) was consecutively modified by nitration, amination and pyridine, and the effect of the different carbon supports on the Ru-based catalysts for acetylene hydrochlorination was investigated. The results of the FT-IR studies confirmed that -NO2, -NH2 and -N-H-N groups were separately grafted onto the surface of the AC. Under the same reaction conditions, the modified catalysts exhibited better catalytic activity compared with the original Ru/AC catalyst. Moreover, the catalyst Ru/AC-NHN showed the best catalytic performance with a slight decrease after 48 h from 93.2% to 91.8%. The increase in catalytic activity indicates that the modification with nitrogen functional groups is beneficial for acetylene hydrochlorination.
- Xu, Na,Zhu, Mingyuan,Zhang, Jinli,Zhang, Haiyang,Dai, Bin
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- Carbon with Surface-Enriched Nitrogen and Sulfur Supported Au Catalysts for Acetylene Hydrochlorination
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Nitrogen-doped carbons supported gold catalysts has attracted much attention in a broad range of applications. However, co-existence of multiple nitrogen species which may have vastly different effect on the gold-based catalysts, has limited the development of an ideal nitrogen-doped carbon support. Herein, we have demonstrated that by addition of sulfur species, selective formation of pyrrolic nitrogen against pyridinic nitrogen can be achieved for pyrrolic nitrogen doped carbon support. The gold catalysts synthesized from the pyrrolic nitrogen doped carbon support produced using ionic liquid-assisted synthetic strategy (Au/N, S-AC-700), exhibited excellent catalytic activity and stability for hydrochlorination of acetylene. The outstanding performance was attributed to the π electrons transferred from pyrrolic nitrogen to Au (III) center, which could increase the electron density of Au hence facilitate the adsorption of hydrogen chloride on the catalyst.
- Wang, Bolin,Zhao, Jia,Yue, Yuxue,Sheng, Gangfeng,Lai, Huixia,Rui, Jiayao,He, Haihua,Hu, Zhong-ting,Feng, Feng,Zhang, Qunfeng,Guo, Lingling,Li, Xiaonian
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- Chlorine-catalysed Pyrolysis of 1,2-Dichloroethane. Part 1.- Experimental Results and Proposed Mechanism
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Experimental studies of the pyrolysis and chlorination of 1,2-C2H4Cl2 in the presence of small proportions of chlorine, or of chlorine plus nitric oxide, confirm that the main propagating steps between 520 and 620 K are .The initial rates (d/dt)0 and (d/dt)0-decrease together as the vessels age, but k2/k3=γ remains constant at constant pDCE. γ increases as pDCE is increased, or if inert gases are added, as expected from unimolecular behaviour of k2, and the Arrhenius parameters of γ increase together as pDCE is increased. γ(p) is evaluated for several ranges of pDCE at five temperatures to allow study of k2(p) by unimolecular theory in Part 2.The addition of VC lowers (d/dt)0 through reaction (-2), and the results are used to evaluate k-2/k1; k-2 is also pressure-dependent.In vessels with fresh surfaces, d(VC)/dt is proportional to pDCExp0.5Cl for low pCl and is independent of added inert gases; in aged vessels, the order in pDCE becomes 0.62, very close to the dependence of γ(p) on pDCE.Calculations of .>0 and .>0 from the observed rates and rate constants point to an initiation step and termination by the reverse reaction in fresh-surfaced vessels, where S is a surface site; with aged surfaces, the results point to the same initiation step combined with termination by especially at lower temperatures.
- Ashmore, Philip G.,Gardner, John W.,Owen, Anthony J.,Smith, Barbara,Sutton, Philip R.
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- Effect of acidity and ruthenium species on catalytic performance of ruthenium catalysts for acetylene hydrochlorination
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Carbon-supported ruthenium catalysts are promising mercury-free catalysts for acetylene hydrochlorination, due to their high activity and relatively low price. However, ruthenium catalysts often suffer from serious deactivation. Herein, a stable RuCl3-A/AC catalyst was prepared by applying a simple ammonia treatment during the impregnation process. The fresh and used ruthenium catalysts were comprehensively characterized using N2 sorption, NH3-temperature-programmed desorption (NH3-TPD), H2 temperature-programmed reduction (H2-TPR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The results show that the RuCl3 species is identified as the active species, and the surface acidity of the RuCl3/AC catalyst is generated mainly from supported RuCl3 species, which can easily cause coke deposition. The enhancement of the stability of the RuCl3-A/AC catalyst is attributed to the formation of RuOx species and the decrease of the surface acidity.
- Wang, Xiaolong,Lan, Guojun,Liu, Huazhang,Zhu, Yihan,Li, Ying
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- The role of KCl in FeCl3-KCl/Al2O3 catalysts with enhanced catalytic performance for ethane oxychlorination
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Among the vinyl chloride production processes, ethane oxychlorination is the most economical and environment-friendly process but constrained by the lack of high performance catalysts for industrial applications. In this work, FeCl3-KCl/Al2O3 catalysts with different molar ratios of K/Fe were prepared by a co-impregnation method and applied to ethane oxychlorination. The FeCl3-KCl/Al2O3 catalyst with K/Fe = 2 exhibited enhanced catalytic performance with the highest conversion of C2H6 (99.1%) and the best selectivity to C2H3Cl (74%) under the optimal conditions of 400 °C, C2H6:HCl:air = 1:3:5.5 (volume ratio) and GHSV = 4560 h-1. It was found that the enhanced catalytic performance could be attributed to the formation of KFeCl4 from KCl and FeCl3 and the change of the reaction process. Besides, KCl is in favor of weakening the interaction between the active species and support. The reduction activation energy of Fe(iii) → Fe(ii) is efficiently reduced by KCl addition. The FeCl3-KCl/Al2O3 catalyst may be a potential catalyst for industry due to its simple composition and convenient preparation.
- Zhou, Qihua,Hu, Ruisheng,Jia, Yun,Wang, Hongye
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- An Alternative Carbon Carrier in Green Preparation of Efficient Gold/Carbon Catalyst for Acetylene Hydrochlorination
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Au catalysts supported with carbon-based carriers have been extensively studied for the hydrochlorination of acetylene and expected to replace toxic mercury catalysts. However, removal of the highly corrosive aqua regia used in the preparation of carbon-based catalysts while maintaining catalytic activity and stability remains a key challenge. Herein, we present a green technology carrier, activated carbon fibers (ACF), to support gold catalysts for the hydrochlorination of acetylene. TPD and XPS analyses confirmed the presence of surface oxygen-containing functional groups (SOGs) and pyrrolic N species on the ACF. The Au/ACF?H2O catalyst exhibited better catalytic activity and stability than Au/ROX0.8(AQ)?H2O. Characterization results revealed that the catalytic properties of Au/ACF?H2O could be attributed to the anchoring and stabilization of gold active species on the SOGs, leading to atomic dispersion, and to the improvement of HCl adsorption with the synergistic effect of electron-donating pyrrolic N groups. The results indicated that usage of this green carrier can be considered as the a new approach to reduce or eliminate the use of strong oxidizing reagents in the preparation of Au catalysts.
- Lai, Huixia,Wang, Bolin,Yue, Yuxue,Sheng, Gangfeng,Wang, Saisai,Feng, Feng,Zhang, Qunfeng,Zhao, Jia,Li, Xiaonian
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- Boron-doped carbon nanodots dispersed on graphitic carbon as high-performance catalysts for acetylene hydrochlorination
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Boron-doped carbon nanodot materials, comprising evenly distributed BC3-nanodots in a layered carbon matrix, are prepared through a pre-assembly assisted carbonization synthetic strategy. The prepared materials are endowed with high electron affinity and distortion resistance, which provides a stable framework while generating affinity to substrates.
- Yue, Yuxue,Wang, Bolin,Wang, Saisai,Jin, Chunxiao,Lu, Jinyue,Fang, Zheng,Shao, Shujuan,Pan, Zhiyan,Ni, Jun,Zhao, Jia,Li, Xiaonian
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- Acetylene hydrochlorination over bimetallic Ru-based catalysts
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Ruthenium-based catalysts including monometallic Ru, bimetallic Ru-Cu and Ru-Co were prepared using spheric active carbon (SAC) as the support, and their catalytic performance was assessed for the acetylene hydrochlorination reaction, characterized by BET, TG, TEM, TPR and XPS. It is suggested that using cobalt as the additive can significantly enhance the catalytic activity of the Ru/SAC catalyst for the acetylene hydrochlorination reaction. Over the 1%Ru1Co3/SAC catalyst the acetylene conversion is maintained above 95% with 48 h on stream under reaction conditions of 170 °C, C2H2 hourly space velocity = 180 h-1 and the feed HCl/C2H2 volume ratio = 1.1; while the addition of copper results in a lower acetylene conversion. It is illustrated that the cobalt additive can greatly influence the amount of ruthenium species involved in RuO2, Ru0, RuOx and RuCl3 in the catalyst, which results in good catalytic activity and capability to inhibit coking of the 1%Ru1Co3/SAC catalyst. The optimal 1%Ru1Co3/SAC catalyst is a promising non-mercuric catalyst for PVC manufacture, with the advantages of both good stability and low cost. The Royal Society of Chemistry 2013.
- Zhang, Jinli,Sheng, Wei,Guo, Cuili,Li, Wei
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- Lanthanide compounds as catalysts for the one-step synthesis of vinyl chloride from ethylene
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The industrial manufacture of vinyl chloride relies on a two-step process involving CuCl2-catalyzed ethylene oxychlorination to ethylene dichloride followed by thermal cracking of the latter to vinyl chloride. This work evaluates a wide range of commercial and self-prepared lanthanide (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er) compounds for the one-step production of vinyl chloride from ethylene in a fixed-bed reactor at 623–773 K and 1 bar using feed ratios of C2H4:HCl:O2:Ar:He = 3–6:1–9.6:1–7:3:80–92 and space times of 6–252 g h mol?1 (based on ethylene). Ex situ characterization by X-ray diffraction, electron microscopy, and X-ray photoelectron spectroscopy reveals that the oxide forms of all compounds, except CeO2, transform into their respective (oxy)chloride. Among all studied systems, CeO2 shows the highest activity but suffers from combustion forming COx, while europium oxychloride (EuOCl) leads to the best vinyl chloride selectivity of 96% at 20% C2H4 conversion for over 100 h on stream. Temperature-programmed reduction with H2, temperature-programmed desorption of NH3, and oxidation tests (C2H4, CO, and HCl oxidation) unravel the unique balance of mild redox and enhanced acid properties of EuOCl compared to CeO2, which suppress over-oxidation and boost ethylene dichloride dehydrochlorination. Strategies to couple the excellent selectivity of EuOCl with the high activity of CeO2 are demonstrated through the synthesis of homogeneous europium-cerium mixed oxides, combining two functions on a single surface. In addition, the engineering of a dual-bed reactor, integrating a CeO2 bed first to produce ethylene dichloride in high yield which is subsequently transformed to vinyl chloride over EuOCl leads to vinyl chloride yields of up to 30% per pass. These very promising findings constitute a crucial step for process intensification of polyvinyl chloride production and exploring the potential of rare-earth compounds in industrially-relevant reactions.
- Scharfe, Matthias,Lira-Parada, Pedro A.,Amrute, Amol P.,Mitchell, Sharon,Pérez-Ramírez, Javier
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- Phosphine-oxide organic ligand improved Cu-based catalyst for acetylene hydrochlorination
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Considering the disadvantages of Cu-based catalyst for acetylene hydrochlorination, such as poor dispersion, severe carbon deposition and insufficient active sites, supported Cu-complex catalysts were synthesized by using phosphine-oxide organic compounds as ligands. A local active domain was successfully constructed based on the complexation of Cu atom to heteroatomic structure in meticulously selected ligands, in which the phenyl group acts as an electron donor to change the CuCl2 active site electronic structure. The density functional theory calculation proved the existence of a strong interaction between triphenylphosphine oxide and CuCl2, and synchronously, electrons on the benzene ring were transferred to the Cl atom in CuCl2, stabilizing the Cu species. This superior activity may be attributed to the heightened adsorption of HCl and weakened C2H2 and vinyl chloride adsorption by the constructed local active domain, which impedes the carbon deposition that promotes the continuous exposure of active sites. Under the reaction conditions: T = 180 ℃, GHSVC2H2 = 180 h?1 and VHCl/VC2H2 = 1.2, the C2H2 conversion of 15%Cu7%TPPO/AC reaches 88%, which was over 30% higher than 15%Cu/AC catalyst. The significantly improved activity and stability of the proposed catalyst provides a reference for green and sustainable production of vinyl chloride.
- Li, Wei,Liu, Yawen,Wang, Bao,Zhang, Haiyang,Zhang, Jinli,Zhang, Tiantong
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- Effect of transition metal oxide doping on catalytic activity of titania for the oxidation of 1,2-dichloroethane
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Transition metal oxides (MOx; M = Cr, Mn, Fe, Ni, Cu)-doped titania solid solution catalysts (10 wt% MOx–TiO2, denoted as 10MOx–TiO2) were prepared by the coprecipitation method. The techniques of XRD, TPR, TPD, XPS, TPSR, and in situ DRIFTS were used to characterize physicochemical properties of the materials, and their catalytic activities were evaluated for the oxidation of 1,2-dichloroethane (1,2-DCE). The introduction of MOx enhanced adsorption and activation of oxygen molecules, mobility of surface lattice oxygen, and low-temperature reducibility. The 10MOx–TiO2 catalysts showed good performance, with 10CrOx–TiO2 exhibiting the highest catalytic activity (reaction rate = 2.35 × 10?7 mol/(gcat s) and apparent activation energy (Ea) =35 kJ/mol at space velocity = 40,000 mL/(g h)) and good resistance to chlorine poisoning, The mechanism of 1,2-DCE oxidation over 10CrOx–TiO2 was also discussed based on the results of TPSR and in situ DRIFTS characterization. It is concluded that strong acidity and redox ability, high adsorbed oxygen species concentration, and strong interaction between TiO2 and CrOx were accountable for the good performance of 10CrOx–TiO2.
- Zhang, Xing,Liu, Yuxi,Deng, Jiguang,Jing, Lin,Yu, Xiaohui,Han, Zhuo,Dai, Hongxing
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p. 623 - 634
(2019/12/27)
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- Carbon-supported copper–organic framework as active catalysts for acetylene hydrochlorination
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In this work, activated carbon supported Cu-MOF was used as an acetylene hydrochlorination catalyst to manufacture vinyl chloride. Cu-MOF/AC with 15 wt. % Cu-MOF content has the initial acetylene conversion of 99.2% and vinyl chloride selectivity of 98.5% at 200 °C. By combining steady-state experiments and physical–chemical characterization results (XPS, BET, H2-TPR, C2H2-TPD, XRD, and HCl adsorption experiments), Cu–O–C is shown to slow the reduction of Cu2+, improve the reactants adsorption, and strengthen the anti-coking ability of Cu-based catalysts. According to the previous studies and the Eley–Rideal mechanism, it is proposed that Cu2+ first adsorbed C2H2 to generate transition states in acetylene hydrochlorination catalysis.
- Han, Yong-Jun,Li, Fu-Xiang,Li, Qing-Bin,Li, Song-Tian,Ma, Yao,Wu, Yi-Bo
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p. 812 - 820
(2021/10/05)
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- Waste cigarette butt-derived nitrogen-doped porous carbon as a non-mercury catalyst for acetylene hydrochlorination
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The development of advanced carbon materials as metal-free catalysts holds great importance for mercury catalyst replacement in acetylene hydrochlorination. In this paper, we transform discarded cigarette butts into a porous nitrogen-doped carbon material (N-CB-800), exhibiting characteristics of high specific surface area, large N doping amount, defective structure and strong C2H2 chemical adsorption ability. These unique features endow N-CB-800 with a high catalytic performance with an acetylene conversion of 71.8% at 220 °C and an acetylene space velocity of 100 h-1, making it one of the most active metal-free catalysts. This work will be of great value for the recycling of living waste and provide meaningful guidance for the development of non-mercury catalysts for acetylene hydrochlorination.
- Feng, Hongbin,Hao, Yalei,Hu, Jiapeng,Jin, Xin,Li, Xingyun,Liu, Chengxiang,Song, Yujiang,Zhou, Yuxin,Zhu, Yan
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p. 19358 - 19363
(2021/11/09)
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- Nitrogen-Doped Carbon-Assisted One-pot Tandem Reaction for Vinyl Chloride Production via Ethylene Oxychlorination
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A bifunctional catalyst comprising CuCl2/Al2O3 and nitrogen-doped carbon was developed for an efficient one-pot ethylene oxychlorination process to produce vinyl chloride monomer (VCM) up to 76 % yield at 250 °C and under ambient pressure, which is higher than the conventional industrial two-step process (≈50 %) in a single pass. In the second bed, active sites containing N-functional groups on the metal-free N-doped carbon catalyzed both ethylene oxychlorination and ethylene dichloride (EDC) dehydrochlorination under the mild conditions. Benefitting from the bifunctionality of the N-doped carbon, VCM formation was intensified by the surface Cl*-looping of EDC dehydrochlorination and ethylene oxychlorination. Both reactions were enhanced by in situ consumption of surface Cl* by oxychlorination, in which Cl* was generated by EDC dehydrochlorination. This work offers a promising alternative pathway to VCM production via ethylene oxychlorination at mild conditions through a single pass reactor.
- Chen, De,Chen, Qingjun,Fuglerud, Terje,Ma, Guoyan,Ma, Hongfei,Qi, Yanying,Rout, Kumar R.,Wang, Yalan
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supporting information
p. 22080 - 22085
(2020/10/02)
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- Method for preparing vinyl chloride by reaction between acetylene and hydrogen chloride
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The invention discloses a method for preparing vinyl chloride by a reaction between acetylene and hydrogen chloride, comprising the following steps of: reacting between acetylene and hydrogen chlorideto prepare vinyl chloride under the action of a biomass-based nitrogen-doped carbon catalyst, wherein the biomass-based nitrogen-doped carbon catalyst is prepared by carbonizing biomass or a mixtureof biomass and a nitrogen source at 400-1000 DEG C, and the biomass is selected from at least one of bamboo processing leftovers, wood processing leftovers, plant straws, plant leaves, cereals, beans,cereal processing leftovers, bean processing leftovers and livestock manure. The method disclosed by the invention has the advantages of simple preparation process, easily available raw materials, low cost, strong process controllability, easiness in large-scale production, high vinyl chloride selectivity and acetylene conversion rate, safety, environmental friendliness and the like.
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Paragraph 0075-0076; 0083-0084
(2020/08/06)
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- GOLD CONTAINING CATALYST, METHOD OF PREPARATION AND USE
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The present invention relates to improvements in known gold containing catalysts. In particular, the present invention relates to improving the stability and/or inhibition of deactivation of gold containing catalysts via the addition of an inorganic oxide, hydroxide, oxo-salt or oxo-acid. There is also disclosed a method for preparing said catalyst most suitably via an impregnation method. Such catalysts are useful in the production of vinyl chloride monomer.
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Page/Page column 13; 15
(2021/01/22)
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- Method for eliminating hydrogen chloride by catalytic cracking of chloralkane
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The invention discloses a method for eliminating hydrogen chloride by catalytic cracking of chloralkane, comprising the following steps of: carrying out a cracking reaction on chloralkane under the action of a biomass-based nitrogen-doped carbon catalyst to eliminate hydrogen chloride so as to prepare corresponding olefin, wherein the biomass-based nitrogen-doped carbon catalyst is prepared by carbonizing biomass or a mixture of biomass and a nitrogen source at 400-1000 DEG C, and the biomass is selected from at least one of bamboo processing leftovers, wood processing leftovers, plant straws,plant leaves, cereals, beans, cereal processing leftovers, bean processing leftovers and livestock manure. The method disclosed by the invention has the advantages of simple preparation process, easily available raw materials, low cost, strong process controllability, easiness in large-scale production, high catalytic cracking conversion rate of the chloralkane, high product selectivity, low energy consumption and the like.
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Paragraph 0089-0094
(2020/08/06)
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- METHOD OF PRODUCING VINYL CHLORIDE
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A method of producing vinyl chloride is provided in the present invention. The method includes the following steps. First, 1,2-dichloroethane (EDC) is introduced into a reactor, and a residence time of the EDC in an ionic liquid catalyst is 5 seconds to 100 seconds, so as to perform a catalytic cleavage reaction. The ionic liquid catalyst is in a liquid phase. The ionic liquid catalyst includes tributylalkyl phosphonium halide, and the alkyl includes an alkyl group having 3 to 16 carbon atoms.
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Paragraph 0031; 0038; 0039
(2020/01/27)
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- Efficient Electrocatalysis for the Preparation of (Hetero)aryl Chlorides and Vinyl Chloride with 1,2-Dichloroethane
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Although the application of 1,2-dichloroethane (DCE) as a chlorinating reagent in organic synthesis with the concomitant release of vinyl chloride as a useful byproduct is a fantastic idea, it still presents a tremendous challenge and has not yet been achieved because of the harsh dehydrochlorination conditions and the sluggish C?H chlorination process. Here we report a bifunctional electrocatalysis strategy for the catalytic dehydrochlorination of DCE at the cathode simultaneously with anodic oxidative aromatic chlorination using the released HCl as the chloride source for the efficient synthesis of value-added (hetero)aryl chlorides. The mildness and practicality of the protocol was further demonstrated by the efficient late-stage chlorination of bioactive molecules.
- Liang, Yujie,Lin, Fengguirong,Adeli, Yeerlan,Jin, Rui,Jiao, Ning
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supporting information
p. 4566 - 4570
(2019/02/14)
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- Preserved in a Shell: High-Performance Graphene-Confined Ruthenium Nanoparticles in Acetylene Hydrochlorination
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The potential implementation of ruthenium-based catalysts in polyvinyl chloride production via acetylene hydrochlorination is hindered by their inferior activity and stability compared to gold-based systems, despite their 4-fold lower price. Combining in-depth characterization and kinetic analysis we reveal the superior activity of ruthenium nanoparticles with an optimal size of 1.5 nm hosted on nitrogen-doped carbon (NC) and identify their deactivation modes: 1) nanoparticle redispersion into inactive single atoms and 2) coke formation at the metal sites. Tuning the density of the NC carrier enables a catalytic encapsulation of the ruthenium nanoparticles into single layer graphene shells at 1073 K that prevent the undesired metal redispersion. Finally, we show that feeding O2 during acetylene hydrochlorination limits coke formation over the nanodesigned ruthenium catalyst, while the graphene layer is preserved, resulting in a stability increase of 20 times, thus rivalling the performance of gold-based systems.
- Kaiser, Selina K.,Lin, Ronghe,Krumeich, Frank,Safonova, Olga V.,Pérez-Ramírez, Javier
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supporting information
p. 12297 - 12304
(2019/08/01)
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- Controlling the speciation and reactivity of carbon-supported gold nanostructures for catalysed acetylene hydrochlorination
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Carbon-supported gold catalysts have the potential to replace the toxic mercuric chloride-based system applied industrially for acetylene hydrochlorination, a key technology for the manufacture of polyvinyl chloride. However, the design of an optimal catalyst is essentially hindered by the difficulties in assessing the nature of the active site. Herein, we present a platform of carbon supported gold nanostructures at a fixed metal loading, ranging from single atoms of tunable oxidation state and coordination to metallic nanoparticles, by varying the structure of functionalised carbons and use of thermal activation. While on activated carbon particle aggregation occurs progressively above 473 K, on nitrogen-doped carbon gold single atoms exhibit outstanding stability up to temperatures of 1073 K and under reaction conditions. By combining steady-state experiments, density functional theory, and transient mechanistic studies, we assess the relation between the metal speciation, electronic properties, and catalytic activity. The results indicate that the activity of gold-based catalysts correlates with the population of Au(i)Cl single atoms and the reaction follows a Langmuir-Hinshelwood mechanism. Strong interaction with HCl and thermodynamically favoured acetylene activation were identified as the key features of the Au(i)Cl sites that endow their superior catalytic performance in comparison to N-stabilised Au(iii) counterparts and gold nanoparticles. Finally, we show that the carrier (activated carbon versus nitrogen-doped carbon) does not affect the catalytic response, but determines the deactivation mechanism (gold particle aggregation and pore blockage, respectively), which opens up different options for the development of stable, high-performance hydrochlorination catalysts.
- Kaiser, Selina K.,Lin, Ronghe,Mitchell, Sharon,Fako, Edvin,Krumeich, Frank,Hauert, Roland,Safonova, Olga V.,Kondratenko, Vita A.,Kondratenko, Evgenii V.,Collins, Sean M.,Midgley, Paul A.,López, Núria,Pérez-Ramírez, Javier
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p. 359 - 369
(2019/01/10)
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- METHOD FOR CHLORINATION AND DEHYDROGENATION OF ETHANE
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The present invention relates to a method for chlorination and dehydrogenation of ethane, comprising: mixing and reacting a low-melting-point metal chloride with C2H6, such that the low-melting-point metal chloride is reduced to a liquid-state low-melting-point metal, and the C2H6 is chlorinated and dehydrogenized to give a mixed gas containing HCl, C2H6, C2H4, C2H2 and C2H3Cl. In the method, the low-melting-point metal chloride is used as a raw material for chlorination and dehydrogenation, and the low-melting-point metal produced after the reaction is used as an intermediate medium. The method has the characteristics of simple process, low cost and high yield. Moreover, some acetylene and vinyl chloride can be produced as by-products at the same time when the ethylene is produced, by controlling the ratio of ethane to the chloride as desired in production.
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Paragraph 0031; 0034; 0037-0039; 0040; 0043
(2018/04/03)
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- METHOD OF PRODUCING VINYL CHLORIDE
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The present invention provides a method of producing vinyl chloride. The method comprises the steps of inletting 1,2-ethylenedichloride gas into a reactor, and performing a catalytic cleavage step of 1,2-ethylenedichloride (EDC) gas in existence of metal organic framework having a specific structure, thereby reaching a conversion rate of EDC between 60% and 90%.
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Paragraph 0052; 0056
(2018/05/15)
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- PROCESS FOR THE PRODUCTION OF CHLORINATED METHANES
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The present invention provides processes for the production of chlorinated methanes via the direct chlorination of methane. The processes include a dehydrochlorination and/or chlorination step that converts up to 100% of the higher chlorinated alkanes in a process stream from the methane chlorination reaction into more highly chlorinated alkanes. These more highly chlorinated alkanes can be easily removed from the process stream. The use of a cost effective feedstream of crude methane is thus rendered possible, without additional capital expenditure for the sophisticated separation equipment required to separate ethane and other hydrocarbon components from the methane feed.
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Paragraph 0062; 0063
(2017/04/11)
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- Catalytic hydrochlorination of acetylene on PdCl2/C supported catalysts: Kinetic isotopic effect of HCl/DCl, stereoselectivity, and mechanism
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Two routes of catalytic hydrochlorination of acetylene were found by the isotopic label method for systems with supported palladium K2PdCl4/C and Н2PdCl4/C catalysts: with formation of the products of syn- and a
- Krasnyakova,Nikitenko,Khomutova,Mitchenko
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p. 533 - 540
(2017/10/11)
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- A methane chloride method of preparing vinyl chloride monomer
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The invention discloses a method for preparing a vinyl chloride monomer by using methane chloride. The method comprises the following steps: by taking methyl chloride and methylene chloride as raw materials, performing oxidative coupling on the methyl chloride and oxygen; performing hydrogenation coupling on the methylene chloride and hydrogen; charging oxygen into the methyl chloride to have a methyl chloride oxidative coupling reaction in the presence of a catalyst which has methane oxidative coupling reaction activity; charging hydrogen into the methylene chloride to have a methylene chloride hydrogenation coupling reaction in the presence of a catalyst which has hydrogenation activity; taking byproduct methylene chloride generated in the methyl chloride oxidative coupling reaction as the raw material for the methylene chloride hydrogenation coupling reaction; taking the byproduct methyl chloride generated in the methylene chloride hydrogenation coupling reaction as the raw material for the methyl chloride oxidative coupling reaction. The method disclosed by the invention is used for preparing vinyl chloride by combined utilization of methyl chloride oxidative coupling and methylene chloride hydrogenation coupling, is higher in selectivity of the vinyl chloride in comparison with a method which adopts a simplex reaction, and has the advantage of increasing the utilization rate of the raw material methane chloride and the yield of the vinyl chloride monomer as far as possible.
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Paragraph 0100; 0101
(2017/05/26)
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- The use of metal nanoparticle/ionic liquid system catalytic acetylene hydrogen chlorination reaction method
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The invention discloses a method for catalyzing ethyne hydrochlorination reaction by utilizing a metal nanoparticle/ionic liquid system. The method comprises the steps that a metal nanoparticle/ionic liquid phase catalytic system is prepared, ionic liquid is surface activity ionic liquid, under the temperature ranging from 60 DEG C to 120 DEG C, hydrogen chloride is pumped into the metal nanoparticle/ionic liquid phase catalytic system, activation is carried out, warming is carried out until the temperature ranges from 140 DEG C to 220 DEG C, ethyne and the hydrogen chloride are pumped, the reaction is carried out, and after processing is carried out, a chloroethylene product gas is obtained. The special surface activity ionic liquid and a metal nanoparticle are subjected to in-situ reaction or compounding, the metal nanoparticle/ionic liquid system is obtained, the metal nanoparticle/ionic liquid system is utilized to catalyze the ethyne hydrochlorination reaction, the ethyne converting rate can reach up to 99% in a maximum mode, the chloroethylene selectivity is larger than 99.5%, and the catalytic system has the best cycling stability.
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Paragraph 0061-0063
(2017/08/25)
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- Compounds and methods for the reduction of halogenated hydrocarbons
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The present application relates to methods for the reduction of halogenated hydrocarbons using compounds of Formula (I): wherein the reduction of the halogenated compounds is carried out, for example, under ambient conditions without the need for a transition metal containing co-factor. The present application also relates to methods of recovering precious metals using compounds of Formula (I) that are absorbed onto a support material.
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Page/Page column 19-20
(2017/12/27)
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- Method for utilizing cold energy of low-temperature ethylene during VCM preparation through ethylene balanced oxychlorination method
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Disclosed is an ethylene vaporization method and device for vinyl chloride preparation through an ethylene balanced oxychlorination method. Ethylene at the temperature of -103 DEG C is utilized to condensate a hydrogen chloride product at the top of a hydrogen chloride column, thereby reducing the load of a refrigerating unit of a hydrogen chloride condenser and saving electricity. At the same time, liquid ethylene is evaporated during the heat exchange process, and no vapor is consumed for heating. The great economic benefit is produced, and environmental noise of operation is reduced. The comprehensive utilization rate of energy is increased, and the energy-saving and cost-reducing, and low-carbon and eco-friendly purpose is achieved.
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Paragraph 0049; 0050; 0051; 0052; 0053
(2017/05/12)
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- PROCESS FOR THE PRODUCTION OF ETHYLENE, HYDROGEN CHLORIDE, AND VINYL CHLORIDE FROM ETHANE
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A process is provided for the chlorination of ethane using chlorine as the chlorinating agent to produce ethylene, hydrogen chloride (HC1) and vinyl chloride monomer (VCM).
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Page/Page column 5-7
(2016/06/13)
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- Dehydrochlorination of 1,2-dichloroethane over Ba-modified Al2O3 catalysts
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Bimodal mesoporous alumina (Al2O3) was prepared using polyethyleneglycol (PEG 20,000) and cetyl trimethyl ammonium bromide as a template. The incorporation of Ba with various loadings was carried out by incipient wetness. Characterization was performed by XRD, N2 sorption isotherms, and pyridine FTIR. Ba can be highly dispersed on Al2O3 covering the strong acid sites of Al2O3. In the catalytic dehydrochlorination of 1,2-dichloroethane (1,2-DCE), the Ba/Al2O3 catalysts present a high activity, of which Al2O3 is most active with 95% conversion at 325 °C, related to the more Lewis acidic Al3+ sites in a tetrahedral environment. 1,2-DCE adsorbs dissociatively on Lewis acid-base pair sites, forming chlorinated ethoxy species, which are supposed to be intermediate species for vinyl chloride (VC) production. At a temperature higher than 400 °C, the dehydrochlorination of VC occurs on the strong acid sites of Al2O3. Ba can promote greatly the selectivity for VC through a decrease in the strong acid sites. A high stable activity for dehydrochlorination and high selectivity for VC can be obtained over Ba/Al2O3 in the presence of oxygen.
- Bai, Shuxing,Dai, Qiguang,Chu, Xinxin,Wang, Xingyi
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p. 52564 - 52574
(2016/06/14)
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- Method for preparing chloroethylene from acetylene and hydrogen chloride in mercuration-free mode
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The invention relates to a method for preparing chloroethylene from acetylene and hydrogen chloride in a mercuration-free mode. The method includes the following steps of firstly, putting acetylene and hydrogen chloride in a first-stage reactor filled with carbon-carried mercury-splash-free metal catalysts after mixing and preheating acetylene and hydrogen chloride, controlling the flowing speed of the mixed gas of acetylene and hydrogen chloride, and obtaining a gas-phase product containing chloroethylene, acetylene and hydrogen chloride; secondly, obtaining the liquid phase crude chloroethylene and the gas phase non-condensed mixed gas after compressing, freezing and separating the gas-phase product obtained the first step; thirdly, putting the non-condensed mixed gas obtained in the second step in a second-stage reactor filled with carbon-carried mercury-splash-free metal catalysts, controlling the flowing speed of the non-condensed mixed gas, and obtaining a gas-phase product containing chloroethylene, acetylene and hydrogen chloride; fourthly, freezing and separating the gas-phase product obtained in the third step. Carbon-carried mercury-splash-free metal catalysts are selected, through the two-stage separation mode, the acetylene conversion rate is the same as that of mercury catalysts, cost is low, and selectivity is high.
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Paragraph 0035; 0036; 0037; 0038; 0039; 0040; 0041
(2016/10/08)
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- A catalytic acetylene dichloroethane process for the preparation of vinyl chloride
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The invention discloses a method for preparing vinyl chloride through catalyzing acetylene and dichloroethane to react. The method comprises the steps: mixing acetylene and dichloroethane steam according to a molar ratio of 1:1-1:4, then introducing into a fixed bed reactor provided with a nitrogen modified catalyst, and carrying out a reaction with the reaction temperature of 180-300 DEG C and the air speed of 20-120 h. The nitrogen modified catalyst takes active carbon as a carrier, and is loaded with a metal salt compound and a nitrogen-containing compound; based on the total mass of the catalyst, the mass percentage of the metal salt compound is 0.01-10%, and the mass percentage of the nitrogen-containing compound is 0.01-10%. Vinyl chloride prepared by the method has the characteristics of high acetylene conversion rate and high vinyl chloride selectivity; and the nitrogen modified catalyst preparation process adopted in the process method is simple, and the cost is low.
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Paragraph 0015; 0016
(2017/02/17)
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- In a nitrogen heterocyclic proton acid ionic liquid as the medium of the method of preparing chlorethylene 'catalysts'
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The invention discloses a method for preparing vinyl chloride by taking an azacyclo-protonic acid ionic liquid as a medium through acetylene hydrochlorination. The method comprises the following steps: by taking the azacyclo-protonic acid ionic liquid which is synthesized by taking an azacycle compound as a raw material as the medium, mixing with a non-mercury catalyst to prepare a catalysis system, feeding the catalysis system into an acetylene hydrochlorination catalysis system firstly, and subsequently feeding acetylene and hydrogen chloride for reaction. The method adopts the ionic liquid as the reaction medium and the non-mercury metal compound as the catalyst, green and environment-friendly liquid phase reaction of acetylene hydrochlorination is achieved, and moreover the azacyclo-protonic acid ionic liquid is simple to prepare, economic and good in application prospect.
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Paragraph 0030
(2017/04/08)
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- PROCESS FOR THE PREPARATION OF VINYL CHLORIDE
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A process for the production of vinyl chloride comprises the step of passing a feed stream comprising ethylene dichloride (EDC) over a catalyst system comprising a dehydrochlorination catalyst and a hydrochlorination catalyst at a temperature, which may be in the range 150 - 350 °C, sufficient to effect dehydrochlorination of the ethylene dichloride to produce vinyl chloride.
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Page/Page column 9; 10
(2016/12/22)
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- An acetylene and methylene chloride coupling reaction for preparing vinyl chloride production dichloroethylene and 1, 1, 2-trichloroethane method of
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The invention relates to a method for preparing vinyl chloride and coproducing dichloroethylene and 1,1,2-trichloroethane by acetylene-dichloromethane coupled reaction, which is characterized by comprising the following steps: mixing acetylene and dichloromethane, and simultaneously carrying out dichloromethane coupled reaction and acetylene hydrochlorination on the acetylene and dichloromethane in a catalyst-filled reactor under the action of the catalyst, wherein the mole ratio of the acetylene to the dichloromethane is 0.5-2.5, the reaction temperature is 200-400 DEG C, the volumetric space velocity of the acetylene-dichloromethane gas mixture is 10-500 h, and the dichloromethane coupled reaction generates dichloroethylene, 1,1,2-trichloroethane and chlorine hydride; and further carrying out acetylene hydrochlorination on the generated chlorine hydride and acetylene to generate vinyl chloride. The method can simultaneously coproduce the dichloroethylene, 1,1,2-trichloroethane and other high-added-value products while producing vinyl chloride, and the process is more economical and has wider industrialization prospects.
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Paragraph 0038; 0039; 0045; 0046
(2017/02/09)
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- PROCESS FOR THE PRODUCTION OF VINYL CHLORIDE, HEAVIES, AND HYDROGEN CHLORIDE FROM ETHANE
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A process is provided for the chlorination of ethane using chlorine as the chlorinating agent to produce hydrogen chloride (HCl) and vinyl chloride (VCM) and heavies.
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Page/Page column 5-6
(2016/06/06)
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- A low content Au-based catalyst for hydrochlorination of C2H2 and its industrial scale-up for future PVC processes
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China has the world's largest polyvinyl chloride (PVC) production capacity, comprising over 20 Mt a-1 and occupying 41% of the world production capacity. However, the production of the PVC monomer, vinyl chloride monomer (VCM), faces unsustainable development due to mercury problems. Over 70% of VCM in mainland China is synthesized through hydrochlorination of C2H2 catalyzed by HgCl2. Mercury and its compounds escaping from the reactors have high chronic toxicity, which is harmful to the environment and to people's health. Therefore, developing a novel mercury-free catalyst is crucial for maintaining a green production of PVC in China. This paper shows a novel low content Au-based catalyst by complexing Au with thiocyanate (-SCN). This chemical complex significantly decreases the electrode potential of Au3+ from 0.926 V to 0.662 V, and hence reduces the probability of its reduction by C2H2. The catalyst preserves a high turnover frequency of 5.9 s-1 based on Au, and over 3000 h testing of a 4 t a-1 pilot-trial shows its promising reactivity (>95%) and selectivity (>99%). Compared with the conventional HgCl2 catalyst, this novel Au catalyst has better reactivity, stability, environmental friendliness and lower toxicity, making it promising for the sustainable development of China's PVC industry.
- Zhou, Kai,Jia, Jinchao,Li, Chunhua,Xu, Hao,Zhou, Jun,Luo, Guohua,Wei, Fei
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supporting information
p. 356 - 364
(2018/04/16)
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- Production of vinyl chloride monomer (by machine translation)
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PROBLEM TO BE SOLVED: selected by preparing a catalyst exhibiting a higher, more efficient production of vinyl chloride monomer and to provide. SOLUTION: catalytic reaction by a solid acid catalyst, 2-Chloropyridin dehydrating ethanol in the method for producing a vinyl chloride monomer, a solid acid catalyst in which the hydrogen-type zeolite, the zeolite is a hydrogen-type, ammonium zeolite dephosphorizing 1 including a first known method of heat treatment in an aqueous solution of ammonium salt of a phosphorus-containing ammonium zeolite obtained in inert gas after deammonification, hydrogen-type zeolite as it is lowered in temperature, to provide a method for producing a vinyl chloride monomer. Selected drawing: no (by machine translation)
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Paragraph 0028
(2016/12/12)
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