Oxychlorination–Dehydrochlorination Chemistry on Bifunctional Ceria Catalysts for Intensified Vinyl Chloride Production

Abstract

Ceria catalyzes the one-step production of the vinyl chloride monomer (VCM) from ethylene with a high yield because of its bifunctional character: redox centers oxychlorinate ethylene to ethylene dichloride (EDC), which is subsequently dehydrochlorinated to VCM over strong acid sites generated in situ. Nanocrystalline CeO2 and CeO2-ZrO2 lead to a VCM yield of 25 % in a single pass, outperforming the best reported systems and reaching industrially attractive levels. The use of CeO2 intensifies the current two-step process within PVC production encompassing CuCl2 -catalyzed oxychlorination and thermal cracking. In addition, ceria-based materials offer stability advantages with respect to the archetypical CuCl2 -based catalysts.

Efficient Electrocatalysis for the Preparation of (Hetero)aryl Chlorides and Vinyl Chloride with 1,2‐Dichloroethane

“…It should be noted that the ethylene and HCl could be efficiently reused to generate DCE via ethylene oxychlorination for further vinyl chloride preparation. [2,15] Therefore,t his protocol should be very useful, since after recycling ethylene and HCl to produce DCE, vinyl chloride would almost be the sole product. Since the atom efficiency of this protocol would be very high, it holds great potential for further application in large-scale vinyl chloride manufacture.T he generation of ethylene also supports the formation of aD CE À ion transition state by electron capture from the Pt surface,follows aprocess similar to that depicted in Scheme 1b to furnish the chloroethyl radical.…”

Dual catalyst system for selective vinyl chloride production via ethene oxychlorination

“…18 In addition, similar to the beneficial effects that ceria provides when used as a carrier, 19 appropriate carriers for CeO 2 could promote the EDC-to-VCM conversion step by introducing acid functionalities that are required for this reaction. 14,16,17,[20][21][22][23][24][25] In fact, as reported in the literature, several acid materials, such as Al 2 O 3 or Pt-Cu/SiO 2 , are active in EDC dehydrochlorination. 20,26 If applied as active carriers or co-catalysts for CeO 2 , these materials can allow integration of oxychlorination and dehydrochlorination reactions in a single catalytic system.…”

“…) and temperatures (623-723 K) that closely match the typical operating window of the state-of-the-art copper chloride-based materials. 14 The absence of deactivationinduced measurement bias was ascertained by measuring the catalytic performance under fixed standard conditions (T = 673 K and F T = 200 cm 3…”

“…12,13 Notably, the evaluation of bulk RuO 2 and CeO 2 in ethene oxychlorination revealed that in contrast to the marginal productivity of EDC and VCM over RuO 2 due to preferential overoxidation into carbon oxides (CO x ), CeO 2 displays a substantial selectivity to these products (80-90%) and activity levels that are comparable to those of benchmark CuCl 2based catalysts. 14 Moreover, in addition to its stable catalytic performance, CeO 2 exhibited one key featurethe ability to directly convert significant amounts of ethene to VCM. The latter catalytic property of CeO 2 offers attractive potential to advance the current VCM production technology as it could eliminate the need for the second EDC-to-VCM step that is conducted at high temperatures and therefore represents one of the most energy-intensive unit operations in the process.…”

Efficient Electrocatalysis for the Preparation of (Hetero)aryl Chlorides and Vinyl Chloride with 1,2‐Dichloroethane

“…A notable amount of HCl was also produced, which was observed in both the outlet flow as well as the reaction solution, and was detected by GC‐MS (Scheme , also see the Supporting Information). It should be noted that the ethylene and HCl could be efficiently reused to generate DCE via ethylene oxychlorination for further vinyl chloride preparation . Therefore, this protocol should be very useful, since after recycling ethylene and HCl to produce DCE, vinyl chloride would almost be the sole product.…”