Supported Ni-based Catalyst For Acetylene Carbonylation To Acrylic Acid(Esters)

Acrylic acid(esters),as an important polymer monomer and organic synthetic raw material,is produced mainly via oxidation of propene in industry.With the gradual increases of petroleum prices,the cost of the process increases gradually.Therefore,it is a necessary choice that positively developing coal chemical industry becomes in our country for the national conditions of rich coal and less oil.Among them,acetylene carbonylation using acetylene from coal to calcium carbide as a raw material has became an alternative route with wide application prospect.Currently,the results of industrial applications and basic research mainly focus on homogeneous catalytic systems at home and abroad.Nickel,iron,cobalt and palladium catalysts have been developed to catalyze the acetylation of acetylene with high yield and selectivity.However,it is difficult to recover catalysts after the reaction,which has become the biggest disadvantage of homogeneous catalyst.Hence,the problem associated with the homogeneous catalyst prompted more researches to the development of heterogeneous catalysts that are easy to separate from products.According to the experience and results of the research group on supported elemental nickel catalyst,the supported elemental nickel catalyst has been prepared firstly by incipient-wetness impregnation for catalyzing the reaction of carbonylation of acetylene to acrylic acid.The influences of chemical forms of nickel,the supports and loading amount on catalytic activity were investigated.The properties of the catalysts were characterized by XPS,XRD and H2-TPR and so on,and then the relationship between structure and activity of the catalysts was studied in depth.It was showed that the supported nickel could catalyze the reaction of carbonylation of acetylene to acrylic acid effectively.The catalytic activity showed a pronounced dependence on the supports,loading amount and reaction conditions.The difference in the interaction between metal and supports caused by different supports does not significantly affect the catalytic activity of the catalysts.The pore size and acidic sites of the catalysts are the main factors affecting the catalytic performance.In terms of the yield of acrylic acid,Ni/Ti02 catalyst supported by Ti02 exhibited a high catalytic activity.In view of the fact that no heterogeneous catalyst with excellent properties for acetylene carbonylation to methyl acrylate,supported nickel-based catalysts were prepared by incipient-wetness impregnation method and ion exchange method,respectively,for catalyzing the reaction of carbonylation of acetylene to methyl acrylate.The influences of preparation methods,precursors and exchange times on the catalytic activity were investigated,and then the reaction conditions were optimized and the stability of the catalyst was evaluated.The activity test results show that the supported nickel bromide has good catalytic effect on acetylene carbonylation to methyl acrylate.Within the scope of the study the yield and selectivity of methyl acrylate can reach 39.01%and 72.20%respectively,but the stability of the catalyst is very poor under the reaction conditions.However,the Ni/HY catalyst prepared by using Ni(OAc)2 as precursor and hydrogen Y zeolite as carrier can recover its catalytic activity after reaction by washing and calcining with organic solvent,and so it has good stability and catalytic activity.Under the optimum experimental conditions,the space-time yield of methyl acrylate can reach 5.92 molMA·(molNi·h)-1.Obviously,the catalytic system not only avoids the corrosion of protonic acid but also has high profitability.