Study On The Catalytic Synthesis Of Acrylamide From The Hydration Of Acrylonitrile

The catalytic hydration of acrylonitrile for acrylamide usingRhodococcus rhodochrous J1 and co-pricipitation copper basedcatalysts was studied in this paper. The parameters of catalyticdistillation technique for this reaction were optimized. Orthogonal array method was used to optimize the reactionconditions for enzyme catalyzed hydration of acrylonitrile. Theoptimal conditions are as the following: temperature, 30 ; pH, 7.5;acrylonitrile concentration, 7%; enzyme diluted times, 5; reaction time,120s. The preparation of copper based catalysts was studied and theco-pricipitated catalyst was found to show higher catalytic activity.The effects of feed method and Cu/Al on acrylonitrile convertion andacrylamide selectivity were studied and the optimal preparionconditions were found as the following: alkali single-feed method witha Cu/Al ratio of 40/60. Under these conditions, the conversion couldreach 90.9% with a selectivity of 99.1%. The catalysts were alsocharactered by XRD and TPR. The results showed that there is a goodcorrelation between the granularity and molar ratio of the malachite,copper aluminum hydrotalcite and catalyst activity. Small particle sizeof malachite and copper aluminum hydrotalcite with proper ratio onthe catalyst is responsible for high activity and selectivity. The synthesis of acrylamide from acrylonitrile by catalyticdistillation was studied. The effects of reactants ratio, catalysts` heightand reaction temperature on acrylonitrile conversion and acrylamideselectivity were investigated and the optimum operating conditionswere obtained as the following: reactant ratio, 5 7:1; catalysts height,400mm; reaction temperature, 80 110 . Under these conditions, theconversion of acrylonitrile was 98%, the selectivity of acrylamide was100%.