Synthesis And Application Of Tri-n-butyl Citrate And Acetyl Tributyl Citrate

Non-toxic plasticizers tri-n-butyl citrate and acetyl tributyl citrate were synthesized from citric acid ,butanol, and acetic acid. The synthesis of these two plasticizers are studied systematically。Cerium (IV) sulfate was selected as the catalyst of esterification, the technological parameters were optimized. The influences of synthesis conditions such as the quantity of catalyst,the mole ratio of citric acid to butanol,reaction temperature and time on esterification and acetylization were studied,and the best technology for synthesis was obtained by orthogonal test. The products were tested by means of IR spectroscopy and chemical analyzation. The optimum conditions for synthesis of tri-n-butyl citrate over cerium (IV) sulfate are, molar ratio of butanol to citric acid , 3.5:1; amount of catalyst, 1.0 % of citric acid; reaction time, 5 hours and reaction temperature, 120℃~130℃.The experiment results indicated that the product yield could arrive at more than 96 percent under the suitable conditions.Methanesultonic acid has been selected as the catalyst used in the acetylization of tributyl citrate through references, The reaction condition of acetylization have also been optimized to reach a very good yield. Which could arrive at more than 85 percent under the suitable conditions.At the same time, the refined synthesis conditions of the two products were also studied, the optimal conditions for alkali washing and decoloration were ensured, temperature of neutralization,60℃; neutralizing agent, solution of sodium hydroxide (5%) ; time of neutralization,40min; acid value after neutralization ; less than 0.2 mgKOH·g-1; active carbon was selected as decolourant, temperature of decoloration was around 80℃; the time should range from 30 to 60min; dosage of active carbon should be 7.5%(mass) of the crude product.