Study On Synthetic Process Of Tri-n-butyl Citrate And Acetyltri-n-butyl Citrate

Studies have shown that dioctyl-phthalate which is the most commonly used plasticizer is toxic and it might induce cancer. Because of its significant security and outstanding plasticity,. tributyl citrate (TBC) and acetyl tri-n-butyl citrate (ATBC) were considered to be phthalate’s non-toxic substitutes. This paper studies the process of synthesizing TBC and ATBC by using citric acid, n-butyl alcohol and acetylating agent. And the pilot plant for this process has been designed.1. This paper took NaHSO4·H2O as the catalyst of esterification. The effects of reaction conditions on the yield of TBC, such as the amount of catalyst used,catalyst feeding way, molar ratio of n-butyl alcohol to citric acid, heating temperature and reaction time, were investigated and the optimal conditions were obtained. Under the optimized conditions with molar ratio of4.6,3%catalyst feeded in saturated solution, heated at150℃with the reaction time of150min, the yield of TBC could reach98.0%. Moreover, the results of neutralization&washing in different alkali concentrations had been obtained, and the proper alkali concentration was6%(in mass concentration).2. The reaction results of using acetyl chloride or acetic anbydride as acetylating agent were compared, and acetic anbydridewas chosen as the acetylating agent in this paper. ATBC was synthesized by using acidic ionic liquid [NH(CH2)5CO]HSO4as catalyst. The effects of reaction conditions on the yield of product, such as the dose of catalyst used, molar ratio of acetic anhydride to TBC, reaction temperature and reaction time, were investigated and the optimal conditions were obtained. Under the optimized conditions with feed molar ratio of1.2,1.5%catalyst, at65℃with the reaction time of45min, the yield of ATBC reached98.9%with small acetic anhydride dosage. When the catalyst was reused for5times, the yield of ATBC was still up to98.2%. 3. Base on the technological conditions obtained from the laboratory scale, pilot plant has been designed for the preparation of ATBC with the scale of30tons/year.