Zeolite Supported Ionic Liquid Catalysts for the Hydrochlorination of Acetylene

Abstract

An efficient and stable heterogeneous Zeolite Supported Ionic Liquid Catalyst (IL/CaX) has been explored in acetylene hydrochlorination reaction. The IL/CaX catalyst exhibits excellent space time yields of vinyl chloride (VCM), when compared to the benchmark of Au/C systems. Through characterization and kinetic studies, the reaction follows a two-site mechanism, which is described as the adsorbed hydrogen chloride on the Ca2+ in zeolite, reacting with the adsorbed acetylene on the cation of ionic liquid to form vinyl chloride. The catalytic reaction takes place at the IL/CaX interface, whilst the upper interphase IL/CaX is not active. The deactivation of the catalyst is caused by the dissolving byproducts in the ionic liquid layer, which can be reactivated by a simple vacuum procedure. It is of great significance to study and develop green non-mercury catalysts, in acetylene hydrochlorination.

Carbon with Surface‐Enriched Nitrogen and Sulfur Supported Au Catalysts for Acetylene Hydrochlorination

“…As showed in Figure b, the activation energy ( E a ) of Au/N, S‐AC‐700 and Au/AC were 48 and 72 kJ/mol , respectively. The large difference between activation energy of Au/N, S‐AC‐700 and Au/AC catalysts implied that the active cationic gold in the catalysts may have distinct electronic environment or the reactions employing different catalysts may occur via different mechanisms ,,. Catalytic performance of Au/N, S‐AC‐700 catalyst was also highly dependent on the HCl/C 2 H 2 ratio (Figure S).…”

“…However, AuCl 3 is a good electron acceptor which is willing to take one Cl − ion from HCl, therefore, sufficient supply of HCl can effectively improve the catalytic performance of Au/N, S‐AC‐700 catalyst (Figure ). Furthermore, the adsorption HCl on the active Au 3+ could further activate the adsorbed C 2 H 2 , leading to a decrease in the activation energy of the reaction (Figure b) …”

“…Hydrochlorination of acetylene catalyzed by carbon supported mercuric chloride (HgCl 2 /C) catalysts with typically mercury content of 10–15 wt %, is one of the most methods to manufacture VCM on an industrial scale. However, mercuric chloride is never a green catalyst due to its toxicity and volatility, inevitable mercuric chloride lost during the reaction can pose serious threat to the environment and human health ,. Therefore, nonmercuric catalytic systems are urgently required in consideration of safety and green chemistry.…”

Design strategies for the development of a Pd-based acetylene hydrochlorination catalyst: improvement of catalyst stability by nitrogen-containing ligands

“…As the selection of non-mercury catalysts poses a signicant challenge, a number of catalytic formulations have been proposed including noble metal chlorides, non-noble metal chlorides [30][31][32][33][34][35] and even non-metallic materials. [36][37][38][39][40][41][42][43][44] Among them, Pd catalysts have been considered to be very effective for the hydrochlorination of acetylene. For example, Hutchings et al explored the catalytic performance of carbon supported with a series of metal chlorides and found that the conversion of acetylene to VCM decreased in the following order: Pd(II) > Hg(II) > Cu(II) $ Cu(I) > Ag(I) > Cd(II) > Zn(II).…”

Adsorption Behavior and Electron Structure Engineering of Pd-Based Catalysts for Acetylene Hydrochlorination

“…Among them, gold-based catalysts are good candidates for commercial success using this approach [1,3], since the reaction conditions are mild for Au and also present comparable catalytic properties to Hg. However, there is still an ongoing research investigating alternative activity catalysts to synthesize VCM by acetylene hydrochlorination approach [18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35].…”