ABSTRACT: 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 4.5h with LiAlH4 and γ-linolenic acid (in the ratio of 40g:100g); for the sulfonation, reaction at 29°C for 3.5h with 150g γ-linolenic
alcohol and 65mL mesyl chloride, then the water phase being extracted with dichloromethane (3×100mL); for the substitution,
the reaction at 80°C for 2.5h with metallic sodium and sulfonate (at a ratio of 8g:100g); and for the hydrolysis, reaction
at 80°C for 2.5h with NaOH and dihomo dioate (at a ratio of 50g:100g). 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.
Journal of Oil & Fat Industries 04/2012; 86(1):77-82. · 1.77 Impact Factor
ABSTRACT: To study the influence of methyl esterification on the ultraviolet absorption of gamma-linolenic acid.
To measure the ultraviolet absorption value of some gamma-linolenic acid product by Ultraviolet Spectrophotometry before and after methyl esterification and to measure the fatty acids formation with gas chromatographic method. Then to do a correlation analysis of the results.
The ultraviolet absorption value of gamma-linolenic acid before methyl esterification was very significantly correlated with that after methyl esterification.
It is feasible to mesure the ultraviolet absorption value of polyunsaturated fatty acids (such as gamma-linolenic acid) without methyl esterification.
Zhong yao cai = Zhongyaocai = Journal of Chinese medicinal materials 10/2007; 30(9):1139-42.
ABSTRACT: To measure the saponification value and fatty acid formation of evening primrose oil, to study the effects of pH value on production yield and fatty acid formation during the saponification reaction, and to provide rationales for the selection of raw material, the enhancement of production yield of saponification, and the encapsulation of gamma-linolenic acid with urea.
To measure fatty acid's formation with gas chromatographic method and to measure the saponification value.
The content of gamma-linolenic acid is 7%-10% in evening primrose oil. The content of gamma-linolenic acid is inversely correlated with that of unsaturated fatty acid. The saponification value, the amount of KOH for saponification of evening primrose oil, and the pH value for subsequent isolations of oils are determined. From the measurement of fatty acids of evening primrose oil in two different cultivation locations, the content of gamma-linolenic acid is determined to be 7%-10%, unsaturated oils account for 90%.
The saponification value of evening primrose oil is between 180-200, pH value of isolated oil is 1.5-2.0 after saponification reaction. Fatty acids mainly include palmitic acid, stearic acid, oleic acid, linolic acid and gamma-linolenic acid.
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 04/2005; 30(5):343-6.
ABSTRACT: To study the effects of all factors during the process of urea encapsulation of gamma-linolenic acid on the purity and yield.
To observe the material proportions, time, temperature and purity using single-factor and two-factor tests.
Single-factor test showed that the optimal ratio of all materials (oil, urea and 95% ethanol) was 1:3:8. A 30% purity after single encapsulation process was obtained, at the best temperature range was - 15 degrees C-20 degrees C, for 24 hours. Two-factor test showed that the optimal ratio of oil, urea and ethanol was 1:3:8, where the concentration of ethanol was 90%-95%. The purity reached 90% or higher, with three-time encapsulation process.
An optimized process was identified where material ratios, encapsulation time, temperature, and ethanol concentrations were determined using single-factor and two-factor tests.
Zhongguo Zhong yao za zhi = Zhongguo zhongyao zazhi = China journal of Chinese materia medica 04/2005; 30(6):433-5.