Arachidonic acid-rich microbial algal oil (43.69% arachidonic acid, and other fatty acids such as 6.68% palmitic acid, 5.81% stearic acid, 5.95% oleic acid, 8.93% linoleic acid, 2.27% linolenic acid, 4.2% arachidonic acid, 3.2% behenic acid, and 10.62% lignocarboxylic acid, among others) was subjected to an amidation reaction with monoethanolamine. The molar ratio of microbial algal oil to monoethanolamine was 1:3, and the reaction medium (n-hexane:anhydrous ethanol = 1:1, v/v) was added according to the mass to volume ratio of 1:1, and a methanol solution of 0.3% sodium methanol was used as an alkaline catalyst, and the reaction was stirred for 2.5 h at 25 C to end the reaction. The fatty acid ethanolamide content was 62.5% by HPLC analysis. The reaction was heated and refluxed at 70 according to urea: 95% ethanol = 1:2 (m/v), and after the urea was completely dissolved, the fatty acid monoethanolamide was added according to the mixed fatty acid monoethanolamide: urea = 1:2 (m/m), and refluxing was continued until the solution became clarified and transparent, and then the reaction was stopped and naturally cooled to room temperature. Then urea package at -40 for 12h, remove and quickly filter separation, and wash the crystalline material with ethanol 2 to 3 times, combined filtrate, transferred to the partition funnel, then add anhydrous ether and hot water, gently shaking, fully extracted several times, and static layering. Get the aqueous phase is urea solution, after a low-temperature crystallization, filtrate concentration after the second crystallization can be obtained urea crystals recycling drying use. Combined with the organic phase, dried with anhydrous Na2SO4, spinning to remove the solvent, to obtain higher purity of arachidonic acid ethanolamine. The purity of the resulting arachidonic acid ethanolamine was increased from 42.17% to 63.18%.
