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.
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.
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.
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.
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.
Non-mercury catalytic acetylene hydrochlorination over bimetallic Au-Co(III)/SAC catalysts for vinyl chloride monomer production
Zhang, Haiyang,Dai, Bin,Wang, Xugen,Li, Wei,Han, You,Gu, Junjie,Zhang, Jinli
, p. 829 - 836 (2013)
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.
Acetylene catalytic hydrochlorination over mechanically pre-activated K2PdCl4 salt: A study of the reaction mechanism
Krasnyakova, Tatyana V.,Zhikharev, Igor V.,Mitchenko, Regina S.,Burkhovetski, Valeriy I.,Korduban, Alexander M.,Kryshchuk, Taras V.,Mitchenko, Serge A.
, p. 33 - 43 (2012)
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.
Catalytic Dehydrochlorination of 1,2-Dichloroethane into Vinyl Chloride over Polyacrylonitrile-Based Active Carbon Fiber (PAN-ACF)
Mochida, Isao,Yasumoto, Yoshinori,Watanabe, Yoshiro,Fujitsu, Hiroshi,Kojima, Yasuhiro,Morita, Makoto
, p. 197 - 200 (1994)
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.
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
Fang, Zheng,Feng, Feng,Guo, Lingling,Jin, Chunxiao,Li, Xiaonian,Lu, Jinyue,Pan, Zhiyan,Pang, Xiangxue,Wang, Bolin,Wang, Saisai,Yue, Yuxue,Zhao, Jia
, p. 334 - 346 (2021)
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.
Synthesis and characteristics of organotin-based catalysts for acetylene hydrochlorination
Wu, Yi-Bo,Li, Bo-Wen,Li, Fu-Xiang,Xue, Jian-Wei,Lv, Zhi-Ping
, p. 447 - 452 (2018)
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.
Non-mercury catalytic acetylene hydrochlorination over Ru catalysts enhanced by carbon nanotubes
Li, Guangbi,Li, Wei,Zhang, Haiyang,Pu, Yanfeng,Sun, Mengxia,Zhang, Jinli
, p. 9002 - 9008 (2015)
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.
Promotional effect of copper(ii) on an activated carbon supported low content bimetallic gold-cesium(i) catalyst in acetylene hydrochlorination
Zhao, Jia,Gu, Shanchuan,Xu, Xiaolong,Zhang, Tongtong,Di, Xiaoxia,Pan, Zhiyan,Li, Xiaonian
, p. 101427 - 101436 (2015)
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.
Effects of nitrogen-dopants on Ru-supported catalysts for acetylene hydrochlorination
Hou, Lijun,Zhang, Jinli,Pu, Yanfeng,Li, Wei
, p. 18026 - 18032 (2016)
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.
Boron and Nitrogen Doping in Graphene for the Catalysis of Acetylene Hydrochlorination
Dai, Bin,Chen, Kun,Wang, Yang,Kang, Lihua,Zhu, Mingyuan
, p. 2541 - 2547 (2015)
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.
Preparation of Au/C catalysts using microwave-assisted and ultrasonic-assisted methods for acetylene hydrochlorination
Wittanadecha,Laosiripojana,Ketcong,Ningnuek,Praserthdam,Monnier,Assabumrungrat
, p. 292 - 296 (2014)
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.
Study of the active site for acetylene hydrochlorination in AuCl3/C catalysts
Chao, Songlin,Guan, Qingxin,Li, Wei
, p. 273 - 279 (2015)
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.
Acetylene hydrochlorination over boron-doped Pd/HY zeolite catalysts
Wang, Lu,Lian, Lizhen,Yan, Haijun,Wang, Feng,Wang, Jide,Yang, Chao,Ma, Lida
, p. 30335 - 30339 (2019)
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.
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Watanabe,Onozuka
, (1962)
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Sustainable Synthesis of Bimetallic Single Atom Gold-Based Catalysts with Enhanced Durability in Acetylene Hydrochlorination
Kaiser, Selina K.,Clark, Adam H.,Cartocci, Lucrezia,Krumeich, Frank,Pérez-Ramírez, Javier
, (2021)
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.
Catalytic properties of Pd/HY catalysts modified with NH4F for acetylene hydrochlorination
Wang, Lu,Wang, Feng,Wang, Jide
, p. 41 - 45 (2015)
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.
Enhanced activity of hydrochlorination of acetylene using melamine-modified activated carbon supported gold catalyst
Dai, Bin,Ma, Ning,Zhang, Haiyang,Wang, Xugen
, p. 9473 - 9477 (2013)
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 %.
Carbon with Surface-Enriched Nitrogen and Sulfur Supported Au Catalysts for Acetylene Hydrochlorination
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
, p. 1002 - 1009 (2019)
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.
Effect of acidity and ruthenium species on catalytic performance of ruthenium catalysts for acetylene hydrochlorination
Wang, Xiaolong,Lan, Guojun,Liu, Huazhang,Zhu, Yihan,Li, Ying
, p. 6143 - 6149 (2018)
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.
An Alternative Carbon Carrier in Green Preparation of Efficient Gold/Carbon Catalyst for Acetylene Hydrochlorination
Lai, Huixia,Wang, Bolin,Yue, Yuxue,Sheng, Gangfeng,Wang, Saisai,Feng, Feng,Zhang, Qunfeng,Zhao, Jia,Li, Xiaonian
, p. 3318 - 3326 (2019)
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.
Acetylene hydrochlorination over bimetallic Ru-based catalysts
Zhang, Jinli,Sheng, Wei,Guo, Cuili,Li, Wei
, p. 21062 - 21068 (2013)
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.
Phosphine-oxide organic ligand improved Cu-based catalyst for acetylene hydrochlorination
Li, Wei,Liu, Yawen,Wang, Bao,Zhang, Haiyang,Zhang, Jinli,Zhang, Tiantong
, (2021/12/08)
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.
Waste cigarette butt-derived nitrogen-doped porous carbon as a non-mercury catalyst for acetylene hydrochlorination
Feng, Hongbin,Hao, Yalei,Hu, Jiapeng,Jin, Xin,Li, Xingyun,Liu, Chengxiang,Song, Yujiang,Zhou, Yuxin,Zhu, Yan
, p. 19358 - 19363 (2021/11/09)
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.
