| Popis: |
Lipophilic antioxidants are used in edible oils and oleaginous foods. Therefore, development of novel lipophilic antioxidant is very important. p-toluenesulfonic acid (PTSA) catalyzed esterification of dihydrocaffeic acid (DHCA) with hexanol was selected as model reaction to investigate the synthesis of lipophilic antioxidant. The highest yield of hexyl dihydrocaffeate was achieved under the following optimum conditions: 1 mol% PTSA, 1:30 molar ratio of dihydrocaffeic acid to hexanol without molecular sieves at 80 °C in 2 h. The relationship between temperature and the forward rate constant gave the activation energy of 22.6 kJ/mol, which indicated that PTSA possessed high catalytic activity in the synthesis of hexyl dihydrocaffeate. In addition, the activity of PTSA was not inhibited by the water produced during esterification process. Importantly, this esterification could even proceed smoothly when initial water content was below 5%. In addition, the esterification of a set of phenolic acids could take place efficiently under the same conditions affording the corresponding esters in good to excellent yields. This established method will provide an efficient method for produce lipophilic antioxidants from various natural phenolic acids.Supported by Scientific and Technological Project of Henan Province (No. 182102110024) and Basic Research Funds of Henan University of Technology (No. 2015RCJH01). Keywords:: Dihydrocaffeic acid, Phenolic acids, Hexanol, p-toluenesulfonic acid, Esterification, Antioxidant |
