Studies On The Impact Of Support Structure To Vinyl Acetate Synthesis Via Acetylene Method And The Catalyst Modification

In order to improve the production capacity of Zn(AC)2/C catalyst for the synthesis of vinyl acetate.This paper studies the influenced factors on the catalytic activity,such as the surface structure and pore size of activated carbon.Based on the above conclusion,different kinds of treatments was used to modify the activated carbon supports.We focus on the relationship between different treatment methods and the surface structure,pore width distribution,and study the influence on the catalytic activity.Some progresses have been achieved,the results are summarized as follows:(1)For the first time,ultrasonic treatment was used in activated carbon catalyst supports in the process of vinyl acetate synthesis.The relationship between ultrasonic treatment and the activated carbon pore size,pore size distribution,specific surface effects was studied.Zn(AC)2/C catalyst was prepared by dipping methods,and determine the production capacity of the catalyst.The results showed that,ultrasonic treatment can change the value of activated carbon specific surface area and pore width.The quantity of mesoporous and marcoporous has been improved.When the treatment time has been reached 1 hour,the catalyst gets the highest production capacity,the production capacity enhanced from 1.83 to 2.31g/(d·ml).When the treatment time was prolonged,the structure of the catalyst heavily changed and the production capacity of catalyst reduced too.(2)Under different atmosphere(N2 and CO2),the activated carbon was treated by high temperature heat treatment,the surface structure of activated carbon was studied.Under N2 atmosphere,heat treatment has little effect on the specific surface area and pore width of activated carbon.And the production capacity of catalyst which choose the heat treatment under N2 atmosphere has little change.Under CO2 atmosphere,heat treatment has a great influence on the surface structure of activated carbon.The specific surface area has a great improvement,and pore volume of mesoporous and macroporous improved too.Under CO2 atmosphere,treatment temperature was 700?,the catalyst production capacity reached 2.35g/(d · ml).When the temperature continues to increase,the catalyst production capacity greatly reduced.(3)Loss on ignition methods was adopted,the reasons for catalyst deactivation have been explored,at a temperature of 200?,the active ingredient is zinc acetate was measured as the reaction time of the loss curve,After a certain reaction time,catalyst the surface area and other values,the loss of active components and the catalyst pore plugging zinc acetate,is one reason for the catalyst deactivation.