Acetylene hydrochlorination is currently an important industrial process used to manufacture vinyl chloride. To date, activated-carbon-supported mercuric chloride (HgCl2/C) catalysts were most widely applied in acetylene hydrochlorination. But, mercury is highly toxic and volatile and may cause serious harm to both workers and the environment. Therefore, it is imperative to find alternatives for mercuric catalysts during acetylene hydrochlorination to promote the sustainable development of PVC production.<br/>In this work, choline chloride modified Ru-based catalyst system with lower Ru content were investigated using the incipient wetness impregnation technique, aiming to find an active and stable catalyst for acetylene hydrochlorination reaction. In this catalyst system, the ChRuCl4 complex was identified as the active center and their catalytic reaction mechanism was proposed. The prepared heterogeneous Ru-10%ChCl/AC catalyst shows perfect activity and long-term stability as well, and the conversion of acetylene remains larger than 99.0% after 400 h at an acetylene space velocity of 50 h-1 and 170 °C. In this system, the redundant ChCl could provide an environment for the ChRuCl4 to be stabilized in Ru(III), thus suppressing the reduction of the active ChRuCl4 complex and the aggregation of the particles during the reaction. The computational results show that ChCl could facilitate the activation of HCl and stabilize the key intermediate of the electrophilic process to promote the hydrochlorination reaction. More importantly, the addition of ChCl in RuCl3 forming the ChRuCl4 complex results in the synergistic effect to augment the activity and stability of Ru-based catalysts due to the enhancement of both nucleophilic and electrophilic abilities in this catalyst system. This efficient and long-term catalyst with a lower price is a competitive candidate in the acetylene hydrochlorination industry.

Efficient and stable Ru(III)/choline chloride catalyst system with low Ru content for non-mercury acetylene hydrochlorination

2019 Spring National Meeting

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