Synthesis of 1, 4-dipalmitoyl Hydroxyproline
|Keywords||L-hydroxyproline 1,4 - dipalmitoyl hydroxyproline Palmitoyl chloride Orthogonal test Response surface analysis Non-aqueous phase enzyme-catalyzed|
1,4 - dipalmitoyl hydroxyproline (1,4-Dipalmitoyl Hydroxyproline), as a major component of one of the collagen hydroxyproline derivative is an effective anti-wrinkle A cosmetic anti-aging additives. In this paper, the condensation reaction of Shotton Bowman (Schotten · Banmamm) chloride ammonolysis and alcoholysis preparation of 1,4 - dipalmitoyl hydroxyproline, and explore 1,4 - dipalmitoyl hydroxyproline non-aqueous phase enzyme-catalyzed reaction. First prepared for the esterification and amidation of palmitoyl chloride, and by the molar ratio of reactants, reaction time and temperature factors were investigated to obtain the preparation of palmitoyl chloride optimum reaction conditions as follows: the reaction molar ratio n (acid) : n (phosphorus trichloride) = 1:2, reaction temperature of 70-80 ° C, reaction time 3 h. . Shotton Bowman, condensation reaction of palmitoyl chloride the ammonolysis and alcohol solution, prepared by the 1,4 - dipalmitoyl hydroxyproline. By single factor experiment to examine the impact of various factors on the preparation of dipalmitoyl hydroxyproline. To obtain reaction conditions: acetone as the organic solvent, the reaction pH of 8 to 9, an organic solvent (acetone) volume fraction of 50%, the reaction temperature was 15 ° C, the molar ratio of n (hydroxyproline): n ( palmitoyl chloride) = 1: 2.4, the reaction time was 4 h. Under this condition, the reaction conversion rate of up to 98.13%, up to 60% yield. In order to get the optimum reaction conditions, the use of orthogonal design and response surface analysis tools to optimize the experimental. The results show that for the yield of the dipalmitoyl hydroxyproline, influence factors of the order of: the molar ratio of GT; reaction temperature GT; volume fraction of acetone gt; reaction time. Obtain the optimal reaction conditions for the organic solvent volume fraction was 55%, the reaction temperature was 15 ° C, the molar ratio of n (hydroxyproline): n (palmitoyl chloride) = 1:2.5, the reaction time is 5 h. The quadratic polynomial mathematical model using three factors and three levels of response surface methodology to establish the reaction and the yield of 1,4 - dipalmitoyl hydroxyproline response value for the response surface and contour The effects of temperature, the volume fraction of the organic solvent and the molar ratio of the yield. Obtained reaction fitting equation, the optimum conditions of the reaction as follows: 55% volume fraction of the organic solvent, the reaction temperature was 15 ° C, the molar ratio n (hydroxyproline): n (palmitoyl chloride) = 1 : 2.5. Under these conditions, the yield up to 58.26%. 3 examines the non-aqueous phase enzymatic synthesis reaction of 1,4 - dipalmitoyl hydroxyproline. Comparative experiments on the enzyme type, the organic solvent, the amount of the enzyme and processing water, etc. factors, it is found better; Lipolase lipase and Savinase protease catalytic effect in the hydrophobic solvent isooctane conversion rate greater; increased enzyme dosage appropriate increase in conversion rate; necessary to add water in the 1-2% is more appropriate, in the case of water is too small or too large, easily lead to the enzyme active in the conversion rate to reduce.