丁基羟基茴香醚同分异构体的分离纯化及其抗氧化活性OA

Butylated hydroxyanisole(BHA)commercially exists as a mixture of two isomers:2-tert-butyl-4-hydroxyanisole(2-BHA)and 3-tert-butyl-4-hydroxyanisole(3-BHA).In order to systematically investigate their individual antioxidant properties,an integrated method combining recrystallization and silica gel column chromatography for the separation and purification of isomers from commercial BHA products was developed.The purification process was monitored and quantified using gas chromatography.Under optimized conditions—utilizing n-heptane as the solvent,a crystallization temperature of 25℃,and a solid-to-liquid ratio of 1∶7 g/mL—the commercial BHA was effectively recrystallized.The resulting mother liquor was subsequently separated via silica gel column chromatography using an ethyl acetate and n-hexane eluent system.Following purification,the purity of 3-BHA increased from 93.58%in the raw material to 99.46%(with an 83.21%recovery rate),while the purity of 2-BHA improved from 6.42%to 99.75%(with a 76.67%recovery rate).The antioxidant activities of the purified individual isomers and their binary mixtures at varying mass ratios were evaluated using DPPH and ABTS+radical scavenging assays.The results revealed that the antioxidant efficacy of 2-BHA and 3-BHA was radical-dependent.The IC50 values for DPPH radical scavenging were 22.46 μg/mL for 2-BHA and 17.56 μg/mL for 3-BHA,whereas those for ABTS+radical scavenging were 45.13 μg/mL and 62.45 μg/mL,respectively.Notably,a mixture of 2-BHA and 3-BHA at a mass ratio of 7∶3 exhibited a synergistic enhancement in DPPH radical scavenging activity compared to either pure isomer.This optimized separation method establishes a theoretical framework for the targeted application and in-depth investigation of individual BHA isomers.