Study Of Acetone Condensation To Isophorone Over Solid Catalyst

Isophorone is a kind of solvent which has superior performance and abroad applications. The condensation of vapour phase acetone to isophorone has a broad development prospect and is also an environmentally benign synthesis route.In this thesis, a series of acid-base compound solid catalysts were prepared by coprecipitation, tested in fixed-bed reactor and characterized by TPD,XRD,TG/DTA,BET,XPS. The relations between catalytic activity and properties of catalysts were discussed. Meanwhile, the effects of the reaction condition on the catalytic performance of the catalysts were investigated. The optimal preparation conditions were as follow: Mg:Al=1:1, solution concentration 0.25mol/L, precipitator 1.5times of the amount of calculation, the precipitator feeding rate was 2.0ml/min, calcination temperature 500℃. Under these conditions, conversion of acetone and selectivity of isophorone were 28.4% and 93.1% respectively. Moreover, there was no distinct deactivation during the 100h catalytic performance evaluation. The catalytic activity droped sharply when it was evaluated under a higher pressure. The reason of catalyst deactivation was analyzed. It was found that some higher non-volatile oligomeric compounds deposited on the catalyst surface, which blocked active site. Calcination was the feasible method for the regeneration of the deactivated catalyst.Furthermore, La(NO3)3 modified catalyst had a better activity at 0.2MPa, the optimal modification condition was as below: La(NO3)3 concentration 2.0%(wt), impregnation time 4h, calcination temperature 300℃. The conversion of acetone and selectivity of isophorone of the modified catalyst were 39.4% and 93.9% repectively.The catalysts prepared by scale up experiment showed no distinct difference of activity from the catalysts prepared in laboratory scale .