Modification Of Surface Oxygenated Groups Of Activated Carbon And Influence Of Surface Chemistry Of Activated Carbon On The Performance Of Gold/carbon Catalyst In Acetylene Hydrochlorination

Acetylene hydrochlorination, used for producing vinyl chloride monomer in coal-rich countries like China, takes an important role in traditional chemical technology. At present, the industrial catalyst used in hydrochlorination of acetylene is mercuric chloride. However, the use of mercuric chloride has leaded to great waste of mercury resource and severe environmental pollution. As a result, it is urgent to find a new green and efficient catalyst to replace mercuric chloride.Recently, the hydrochlorination of acetylene using carbon supported gold as catalyst has been a hotspot. One advantage of using this metal is its higher activity, compared with the mercury-based catalyst, allowing the use for industrial application. Although gold can be considered as the best catalyst in terms of initial activity, severe deactivation is still the main problem of the supported gold catalyst. The activated carbon as support is an indispensable part of a catalyst and can in a way affect catalytic performance. The main purpose of this work is to study the relationship between the surface chemistry of activated carbon and the performance of respective gold-supported catalyst in the acetylene hydrochlorination. Following is the main works and results:1. Liquid phase oxidation process using concentrated nitric acid solution and thermal treatments under different temperatures were applied to bring in and selectively get rid of surface oxygenated groups, respectively. The results prove that the method used in this work can successfully modify the surface chemistry of activated carbon selectively, without influencing the textural properties.2. A set of modified activated carbon with different levels of surface oxygenated groups, but with no major differences in their textural parameters, was used to support gold as catalyst in acetylene hydrochlorination, in order to investigate the relationship between the surface chemistry of activated carbon and the performance of respective gold-supported catalyst. The DFT calculations, combined with reaction results, confirmed that the catalytic performance including activity and stability of Au/AC catalyst is improved with the increasing amount of surface oxygenated groups, especially phenol, ether, and carbonyl.