Study On The Process Route Of Preparing Isobutylene From Biomass Ethanol

In chemical production,isobutylene has always been one of the important basic chemical raw materials.Isobutylene can be classified into isobutylene in cracked C4 raffinate depending on the source of production,as well as high-purity isobutylene.The supply and price of isobutylene in traditional chemical production has been subject to crude oil.At present,isobutylene in China is largely dependent on imports.In order to prevent instability and price fluctuations in isobutene supply due to regional wars,shortage of fossil resources,and export restrictions of isobutylene,we urgently need to find renewable raw materials for the production of isobutylene.The technology of producing ethanol by fermentation of grain crops is mature,and the research on the conversion of agricultural and forestry waste(cellulose)into ethanol has also made some progress.It can be seen that biomass ethanol is a bio-based platform molecule with stable source production technology and can be catalytically converted into a variety of important chemical raw materials.In this study,the Zn1Zr10Oz catalyst prepared by impregnation method was used to catalyze the conversion of ethanol.The effects of different ratios of ethanol and water in the raw materials,the ratio of zinc to zirconium of the catalyst,mass space velocity and catalyst loading on the reaction were investigated.The research work shows that the reaction condition:450?,the Zn1Zr10Oz catalyst,n(ethanol)/n(water)=1/10 and 0.1 g catalyst loading is optimal.Under this reaction condition ethanol can be 100%converted,and the yield of the product acetone is>97%.Catalyst Zn1Zr10Oz can efficiently catalyze the conversion of ethanol to acetone.Through experimental investigation and subsequent literature search,the conversion of acetone to isobutylene is a speed control step for the conversion of ethanol to isobutylene.In the conversion of acetone to isobutylene,we used 20%WO3/SBA-15 rich in L acid as a catalyst.It was found that 20%WO3/SBA-15 catalyzed acetone conversion at 300?,the highest conversion of acetone reached 93.2%,and the highest selectivity of isobutylene reached 97.8%.Finally,two optimal catalysts in the two-step experiment of converting ethanol to acetone and acetone to isobutylene combined catalytic ethanol and water system conversion.We have successfully prepared isobutene by combined catalytic experiments.This research work shows that the reaction condition:450 ?,0.1 g ZnlZr10Oz and 0.7 g 20%WO3/SBA-15 catalyst loading,n(ethanol)/n(water)=1/2.5 and,F/W=5.92 h-1 is optimal.Under the reaction condition,the ethanol conversion rate is 100%and isobutylene maximum selectivity is about 68%.Catalyst life test can confirm that catalyst life is about 70 h and it can be regenerated by roasting under air conditions.