Acetylene Dimerization Intensified By Modified Nieuwland Catalyst In Aqueous System

The chloroprene manufactured by acetylene method including monomer chloroprene generation and chloroprene polymerization, and dimerization of acetylene in Nieuwland catalyst to produce monovinylacetylene(MVA) is a key operation unit for neoprene rubber manufacture in acetylene route. But acetylene has low solubility in traditional catalyst, and is prone to react with MVA to form divinylacetylene(DVA) and other byproducts, which harms to economic cost. In order to solve these problems, the modified Nieuwland catalyst obtained by adding graphene, graphene oxide and ionic liquid would improve the catalyst activity and regulate the acetylene dimerization process route. In addition, this work also introduced ultrasonic in the catalytic system to intensify the catalyst performance.(1) Graphene was added to the Nieuwland catalyst form the graphene-Nieuwland catalyst. The experimental results showed that graphene and CuCl mass ratio was 0.081 mg/g, space velocity of acetylene was 160.48 h-1, the temperature was 80 ?, acetylene conversion rate could be increased from 20.48% to 25.16% and MVA selectivity can be increased from 88.65% to 91.18%. At the same time, the possible mechanism of improving catalyst's performance analyzed with ultraviolet spectrum and FT-IR was that graphene enhanced the solubility of acetylene.(2) According to the experimental results of graphene, the GO which had the same structure with graphene and the rich oxygen contained functional groups was studied about influence to the process of acetylene dimerization. And it showed that the catalyst was highly active at 80 ?, conversion of acetylene increased with GO's amount. And it could be increased from 20.48% to 26.97% when GO and CuCl mass ratio is 0.073 mg/g, space velocity of acetylene is 160.48 h-1, while the MVA selectivity showed a trend of decrease after the first increase and it increased from 88.65% to 94.31% when GO and CuCl mass ratio was 0.041 mg/g, space velocity of acetylene was 160.48 h-1. It showed that GO could improve the catalyst performance. The Ultraviolet spectrum showed that GO could form coordination compounds with Cu(?), and the electronic and space steric effection worked together to strengthen acetylene dimerization. The result of Infrared spectrum analysis and thermal analysis showed that precipitation was composed of NH3, C2H2, CuCl and GO.(3) The experiment of considering the ionic liquid improve performance of the Nieuwland catalyst for the dimerization of acetylene. The content of ionic liquid, temperature and other factors were discussed, the experimental results showed that acetylene conversion rate could be increased from 20.48% to 24.63%, MVA% increased from 9.63% to 12.2% and DVA% increased from 0.5% to 0.93% when CuCl and [BMIm]Cl mass ratio was 30.75:1, space velocity of acetylene was 160.48 h-1, the temperature was 80 ?. At the same time, the modern chemical analysis method and calculation showed that the activity of acetylene-? complex, acetylene-? complex and MVA-? complex was increased because of augmented energe of them, and which explained the reseason of the increased of MVA%?DVA%.(4) The work also introduced ultrasonic in the catalyst system, the experimental results showed the acetylene conversion could be increased from 20.48% to 25.76% and MVA selectivity could be increased from 88.65% to 92.19% when space velocity of acetylene was 160.48 h-1, the temperature was 80 ?. It was said that ultrasonic could improve performance of Nieuwland catalyst.