75-01-4Relevant articles and documents
Non-mercury catalytic acetylene hydrochlorination over a NH4F-urea-modified Pd/HY catalyst for vinyl chloride monomer production
Wang, Lu,Wang, Feng,Wang, Jide
, p. 3019 - 3023 (2016)
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.
High performance of supported Cu-based catalysts modulated via phosphamide coordination in acetylene hydrochlorination
Hu, Yubing,Wang, Yan,Wang, Yulian,Li, Wei,Zhang, Jinli,Han, You
, (2020)
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.
An efficient Au catalyst supported on hollow carbon spheres for acetylene hydrochlorination
Kang, Lihua,Zhu, Mingyuan
, p. 31812 - 31818 (2019)
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.
Active carbon supported S-promoted Bi catalysts for acetylene hydrochlorination reaction
Hu, Di,Wang, Lu,Wang, Feng,Wang, Jide
, p. 1413 - 1416 (2018)
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.
Unimolecular HCl elimination from 1,2-dichloroethane: A single pulse shock tube and ab initio study
Rajakumar,Reddy,Arunan
, p. 8366 - 8373 (2002)
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.
Hydrochlorination of acetylene using expanded multilayered vermiculite (EML-VMT)-supported catalysts
Xin-Huang,Yu, Feng,Zhu, Ming-Yuan,Ouyang, Fei-Hong,Dai, Bin,Dan, Jian-Ming
, p. 1101 - 1104 (2015)
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.
Kinetics of acetylene hydrochlorination over bimetallic Au-Cu/C catalyst
Wang, Shengjie,Shen, Benxian,Song, Qinglei
, p. 102 - 109 (2010)
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.
An Au-Cu bimetal catalyst for acetylene hydrochlorination with renewable γ-Al2O3 as the support
Zhao, Jigang,Zeng, Junjian,Cheng, Xiaoguang,Wang, Lei,Yang, Henghua,Shen, Benxian
, p. 16727 - 16734 (2015)
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
Chlorocuprate(i) ionic liquid as an efficient and stable Cu-based catalyst for hydrochlorination of acetylene
Ren, Yanfei,Wu, Botao,Wang, Fumin,Li, Hang,Lv, Guojun,Sun, Mingshuai,Zhang, Xubin
, p. 2868 - 2878 (2019)
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.
Novel nonmetal catalyst of supported tetraphenylphosphonium bromide for acetylene hydrochlorination
Li, Xiaoyan,Nian, Yao,Shang, Shanshan,Zhang, Haiyang,Zhang, Jinli,Han, You,Li, Wei
, p. 188 - 198 (2019)
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.
