Preparation of lipophilic alkyl (hydroxy)benzoates by solvent-free lipase-catalyzed esterification and transesterification

• Published in: Applied microbiology and biotechnology 2008-08, Vol.80 (1), p.29-36
• Main Authors: Vosmann, K, Wiege, B, Weitkamp, P, Weber, N
• Format: Article
• Language: English
• Subjects: 3-Hydroxybenzyl oleate; Alcohol; Antioxidants; Benzoates - chemistry; Benzoates - metabolism; Bioconversions. Hemisynthesis; Biological and medical sciences; Biotechnological Products and Process Engineering; Biotechnology; Catalysis; Chemical reactions; Chromatography; Crystallization; Deacidification; Distillation; Drying agents; Enzymes, Immobilized - genetics; Enzymes, Immobilized - metabolism; Esterification; Esters - chemistry; Esters - metabolism; Fundamental and applied biological sciences. Psychology; Fungal Proteins; Immobilization of enzymes and other molecules; Immobilization techniques; Immobilized lipase B from Candida antarctica (Novozym 435); Industrial Microbiology; Life Sciences; Lipase - genetics; Lipase - metabolism; Methods. Procedures. Technologies; Microbial Genetics and Genomics; Microbiology; Oleyl 4-hydroxy-3-methoxybenzoate (Oleyl vanillate); Oleyl 4-hydroxybenzoate; Sodium; Solvents; Studies; Sulfuric acid; transesterification; Vacuum distillation
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-008-1534-y

Long-chain alkyl benzoates, e.g., lauryl 4-hydroxybenzoate, palmityl 4-hydroxybenzoate, and oleyl 4-hydroxy-3-methoxybenzoate, are formed in high to moderate conversion by lipase-catalyzed transesterification of the corresponding short-chain alkyl benzoates (0.3 to 1 mmol) with fatty alcohols in an equimolar ratio. The substrates are reacted in vacuo in the absence of solvents and drying agents in the reaction mixture. Immobilized lipase B from Candida antarctica (Novozym 435) demonstrates higher activity for the transesterification of various methyl (hydroxy)benzoates with long-chain alcohols than for the corresponding esterification reactions. For example, transesterification activity is around 25-fold higher than esterification activity for the preparation of oleyl 4-hydroxybenzoate. The relative transesterification activities of methoxy- and hydroxy-substituted methyl benzoates found for Novozym 435 are as follows: 2-methoxybenzoate [almost equal to] 3-methoxybenzoate > 4-methoxybenzoate > 3-hydroxybenzoate [almost equal to] 2-hydroxybenzoate > 4-hydroxybenzoate [almost equal to] 4-hydroxy-3-methoxybenzoate [almost equal to] 3-hydroxy-4-methoxybenzoate > > 3,4-dihydroxybenzoate. With respect to the position of the substituents at the phenyl moiety of methyl benzoates, transesterification activity of Novozym 435 increases in the order ortho [almost equal to] meta > para. Compounds with inverse chemical structure, e.g., (methoxy)benzyl alkanoates, are formed in much higher rates both by esterification and transesterification than the analogous alkyl benzoates. Purification by deacidification, crystallization, or vacuum distillation yielded 74% to 89% of the reaction products.