Study On A Clean Process For Preparing Sebacic Acid By Catalytic Cracking Of Castor Oil

Sebacic acid is an important chemical raw materials, it can be used to produce cold-resistant plasticizer, high-quality engineering plastics, epoxy curing agents and sebacic anhydride, etc. Currently, in our country, sebacic acid is mainly produced by cracking of castor oil. The disadvantage is that the cresol and lead oxide used in this process are poisonous. At the same time, the reaction requires excess sodium hydroxide and sulfuric acid, it is a waste of resource and increases the emission of pollutants.This study chose paraffin as the clean diluent and iron oxide as the environmental friendly catalyst to solve the problems mentioned above. The results showed that the catalytic activity of iron oxide was equal to lead oxide and expected to take the place of lead oxide in the production of sebacic acid. The experiments obtained the optimum conditions were as follows:the the ratio of catalyst and castor oil was1%by weight, the ratio of diluent was4:1, the ratio of sodium hydroxide was1:1, the reaction temperature was280℃and the reaction time was4h, the yield of sebacic acid could reach to67.2%under this condition.From the view of energy-saving and emission-reduction, methanol was used to recover the alkali and diluent in the castor oil lysate. Finally, the recoveries of alkali, liquid paraffin and the product were83.3%,85.4%and95.8%respectively, while the loss of methanol solvent was only14.6%. The product was detected by thin-layer chromatography, Fourier transform infrared map and the melting point measuring, the results showed that the content of sebacic acid reached to99.3%, the moisture was0.28%, the ash was0.15%, the alkali fusion chroma was40and the melting point was132.6℃The quality of the sebacic acid reached the first grade standard of GB2092—80. The content of residual iron in the product was92.8μg/g, and proved that the sebacic acid produced by this way can be used as feedstock for the production of cosmetics.Combined with the experimental data, we designed a clean process for a sebacic acid factory with annual production of10000tons through the chemical software Aspen Plus. According to the simulation results, the equipments were selected and designed preliminarily. The economic estimate showed that the annual revenue could be more than15million yuan, and it had better economic and social benefits.