Catalytic Performance Studies On Solid Organic Acid Catalysts

Currently,the traditional plasticizers of dioctyl phthalate and new nontoxic eco-friendly plasticizer of tributyl citrate have received more and more attention at home and abroad as the most widely used types of plasticizers.As the environmentally-friendly catalyst,solid organic acid catalysts have been widely applied to all fields with its unique catalytic performances,it has become one of the hotspots of current research.In this paper,the solid organic acid catalyst was prepared and applied to the synthesis reaction of DOP and TBC,and achieved satisfactory results.Firstly,catalyst was prepared in this paper.With B-type silica gel as a carrier,the styrene polymerized and loaded on the carrier,modified it by adding surfactant,then the solid organic sulfonic acid catalyst was synthesized by sulfonating the styrene with sulfuric acid.The effect of adding surfactant to the catalyst was investigated.At the same time,the structures and properties of catalyst were analyzed by the characterization methods of elemental analysis,BET,NH3-TPD,SEM,etc.As measured by chemical titration method,the acid amounts of the solid organic sulfonic acid catalyst was 2.74mmol·g-1.This paper applied catalyst prepared to the synthesis reaction of traditional plasticizers of dioctyl phthalate.The effects of reaction conditions on the synthesis reaction,such as molar ratio of phthalic anhydride to iso-octanol,reaction time,reaction temperature and the amount of catalyst,were investigated and the optimal conditions were obtained.Under the optimized conditions with molar ratio of 1:2.5,reaction time of 3h,reaction temperature of 170?,catalyst feeded of 4%of the reaction system total mass,the yield of DOP reached 92.5%,esterification rate reached 91%;When the catalyst was reused for 6 times,the yield of DOP was still up to 87%,esterification rate was up to 82%.This paper applied catalyst prepared to the synthesis reaction of new nontoxic plasticizers of tributyl citrate.Like synthesis reaction of DOP,the effects of various factors on the synthesis reaction were investigated and the optimal conditions were obtained.In addition,the reaction mechanism was investigated.Under the optimized conditions with molar ratio of 1:4,reaction time of 2.5h,reaction temperature of 140?,catalyst feeded of 4%of the citric acid,the yield of TBC reached 88.1%,esterification rate reached 93.9%;When the catalyst was reused for 6 times,the yield of TBC was still up to 85%.Contrast with several common solid acids catalyst,our catalyst exhibited a high reactivity and reusability.At the same time,the reasons of catalyst deactivation were explored preliminary by the method of chemical titration method,elemental analysis and thermogravimetric analysis.Finally,the fixed bed reactor was applied to the synthesis reaction of TBC and a preliminary inquiry was made for the industrial continuous production of TBC.