Research On Preparing Sebacic Acid By Activated Carbon Loaded Iron Oxide Catalytic Cracking Of Castor Oil

Sebacic acid is raw materials of production of cosmetics, additives and surfactant, Mainly by the castor oil cracking in high temperature and alkali. The laboratory researchers propose the clean cracking process with iron oxide catalyst and liquid paraffin to solve the serious pollution problem in tradition process. However, using ferric oxide power can lead to high iron content and catalyst can’t recycle, for this problem, using ctivated carbon loaded iron oxide as catalyst by in cracking of castor oil, looking forward to establishing feasible clean production process.Preparation of activated carbon loaded iron oxide catalyst by immersion precipitation: With nitric acid treated activated carbon as carrier, ferric nitrate solution as the impregnation liquid, using sodium hydroxide as precipitant, by filtering, washing, drying, roasting and other steps can get activated carbon loaded iron oxide catalyst. Studied the factors influencing the catalyst activity, getting the best catalyst preparation conditions as follows:with coal based activated carbon as carrier, loaded the iron content is8%, calcination temperature is350℃, calcination time is4h.The best preparation conditions of catalyst are used in castor oil pyrolysis reaction, studying the effect of pyrolysis process conditions, the best pyrolysis process conditions as follows:the dosage of castor oil is15mL, catalyst dosage is5%castor oil by weight, the dosage of40%NaOH is15mL, the dosage of diluent is60mL, the reaction temperature is280℃, the reaction time is3h, sebacic acid yield is66.7%, the highest iron content of product is76.3μg/g, reach the requirement of GB2092-80, iron content of product markedly lower than iron oxide pow er as a catalyst for castor oil cracking reaction is820.2μg/g.TG/DTG tests show that loaded Fe(OH)3decompose form Fe2O3at about350℃, combing with reaction tests show iron loaded in catalyst is basically stable. Using SEM-EDAX、SEM、XRD to test and characterize fresh and used catalyst. The result show that the iron content of fresh and used catalyst are9.61%and8.99%respectively, the morphology of iron deposits has no significant change, and a-Fe2O3peak shape in XRD has no obvious change.Reaction kinetics of preparation of sebacic acid by castor oil cracking is discussed, experimental data fitting in the relationship between ricinoleic acid concentration and time under different temperatures, finding ricinoleic acid cracking reaction conforms to the pseudo first order kinetics, at the temperature of260℃,270℃and280℃, the reaction rate constants are0.5907h-I,0.8363h-I,1.1717h-I, the castor oil cracking reaction apparent activation energy by calculating is20.7KJ/mol.