title: Ultrasound accelerated esterification of palmitic acid with vitamin C.
abstract: The esterification of palmitic acid with vitamin C in the presence of concentrated sulfuric acid as the solvent and catalyst by means of 25 kHz ultrasonic irradiation to obtain l-ascorbyl 6-palmitate is studied. By using ultrasound the dissolution rate of the reactants can be accelerated greatly, the reaction time of esterification can be reduced from 36 to 2h, and better yield (90-93%) of ester can be given by using 95% concentrated sulfuric acid as the solvent and catalyst, contrast to the yield of 75-85% by using 99% concentrated sulfuric acid without ultrasound. The influence of reaction conditions and ultrasonic parameters to the yield of ascorbyl palmitate are reported.
authors.affiliation: State Key Laboratory of Solid Lubrication, LanZhou Institute of Chemical Physics, Chinese Academy of Sciences, LanZhou 730000, People's Republic of China. webi@263.net
authors.forename: Bin
authors.initials: B
authors.lastname: Wen
authors.forename: Wumanjiang
authors.initials: W
authors.lastname: Eli
authors.forename: Qunji
authors.initials: Q
authors.lastname: Xue
authors.forename: Xin
authors.initials: X
authors.lastname: Dong
authors.forename: Weimin
authors.initials: W
authors.lastname: Liu
mesh_terms: D001205:Ascorbic Acid / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000528:radiation effects*; D002384:Catalysis; D004307:Dose-Response Relationship, Radiation; D004951:Esterification / Q000528:radiation effects; D011829:Radiation Dosage; D013010:Sonication; D013696:Temperature
chemical_list: D001205:Ascorbic Acid; C031226:6-O-palmitoylascorbic acid