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Optimization of Synthetic Conditions for the Preparation of Dihomo‐γ‐Linolenic Acid from γ‐Linolenic Acid
Author(s) -
Xue Gang,
Liu Fengxia,
Wang Ying,
Huang Kaixun
Publication year - 2009
Publication title -
journal of the american oil chemists' society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 117
eISSN - 1558-9331
pISSN - 0003-021X
DOI - 10.1007/s11746-008-1320-0
Subject(s) - chemistry , decarboxylation , hydrolysis , linolenic acid , acid hydrolysis , yield (engineering) , crystallization , nuclear chemistry , medicinal chemistry , organic chemistry , catalysis , fatty acid , materials science , linoleic acid , metallurgy
Orthogonal experiments were employed to optimize the correlated parameters of reduction, sulfonation, substitution and hydrolysis. These reactions were used to convert γ‐linolenic acids into dihomo‐γ‐linolenic acids (DGLA). For the reduction, the best reaction conditions were at 35 °C for 4.5 h with LiAlH 4 and γ‐linolenic acid (in the ratio of 40 g:100 g); for the sulfonation, reaction at 29 °C for 3.5 h with 150 g γ‐linolenic alcohol and 65 mL mesyl chloride, then the water phase being extracted with dichloromethane (3 × 100 mL); for the substitution, the reaction at 80 °C for 2.5 h with metallic sodium and sulfonate (at a ratio of 8 g:100 g); and for the hydrolysis, reaction at 80 °C for 2.5 h with NaOH and dihomo dioate (at a ratio of 50 g:100 g). The four reactions gave yields that exceeded 90% for each step. Finally, crystallization and decarboxylation provided DGLA in an overall yield of 60% and >95% purity.