Recovering Technology Of Adipic Acid And The Relative Fundamental Research

Adipic acid is the most important dicarboxylic acid, and it is a valuable raw material used in the chemical industry. There is a large amount of acidic washing water from the bionic catalytic oxidation of cyclohexane, and the main component is adipic acid. In this study, the nitric acid oxidation process for the acidic washing water and the corresponding basic research were done in order to improve the process of cyclohexane oxidation and recover adipic acid from the acidic washing water.A method for simultaneous determination three kinds of dicarboxylic and three kinds of monocarboxylic acids, namely, propionic acid, butyric acid, valeric acid, adipic acid, glutaric acid, and succinic acid, by reversed-phase high performance liquid chromatograph was developed. The suitable chromatography conditions were obtained. Acidic washing water from cyclohexane oxidation was analysed, which is the base of disposing acidic washing water and reclaiming adipic acid.By the oxidation method with nitric acid, the acidic washing water from cyclohexane oxidation was treated successfully. Some factors of influencing the quality of adipic acid, such as the nitric acid amount, reaction time, catalyst amount, reaction temperature, and the reaction mode, were investigated. The highest reclaiming yield of adipic acid is obtained using 55～70% of nitric acid (65%) to oxidate the raw material at 70～80℃for 1.5h, with catalyst 300×10-6～600×10-6, and the cooling process is needed. At these conditions, the reclaiming yield of adipic acid is 100%, and the purity can be more than 99% by recrystallization.The metastable zone width of adipic acid in the six solvents, namely, water, cyclohexanone, cyclohexanol, and the three mixtures of cycloheanone and cyclohexanol, were measured at the range of 27～80℃. The metastable zone width decreases with the increase of temperature and the stirring rate, while the increase of cooling rate will result in broadening of the width of metastable zone. The effects of the operational parameters, such as the water amount, cryatal temperature, cooling rate, and seed amount, on the crystal size distribution (CSD), yield and purity of the products were studied in this thesis.Four carboxylates, namely, dimethyl adipate, diethyl adipate, diethyl glutarate, and diethyl succinate were synthesized catalyzed by sodium bisulfate. The optimized reaction conditions were decided. The effects of the molar ratio of reactant, amount of...