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Optimization of Enzymatic Synthesis of Tricaprylin in Ionic Liquids by Response Surface Methodology
Author(s) -
Pan Qiuyue,
Yang Liping,
Meng Xianghe
Publication year - 2013
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/s11746-012-2186-8
Subject(s) - lipase , ionic liquid , chemistry , caprylic acid , hexafluorophosphate , hexane , glycerol , solvent , yield (engineering) , catalysis , response surface methodology , organic chemistry , chromatography , nuclear chemistry , enzyme , fatty acid , materials science , metallurgy
Ten 1,3‐dialkylimidazolium‐based ionic liquids (ILs) have been investigated as media for the enzymatic synthesis of tricaprylin, in comparison with the conventional organic solvent hexane. The results suggested that the esterification activity of Novozym 435 was higher than Lypozyme RM IM in all the ILs assayed. Novozym 435 showed higher catalytic activity in ILs with anions Tf 2 N − and PF 6 − than in BF 4 − and hexane. FTIR analysis of the secondary structure of the lipase indicated that a smaller decrease of the α‐helix was observed in [C 4 MIM] Tf 2 N and [C 4 MIM] PF 6 than [C 4 MIM] BF 4 and hexane, indicating that the anions of ILs might be a key factor for the activity of lipase in ILs. Process parameters (amount of lipase, caprylic acid/glycerol molar ratio, temperature and their interactive effects) were optimized in 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C 4 MIM]PF 6 ) using Novozym 435 by response surface methodology. When the reactions were performed with the lipase amount of 6.1 % substrate mass at a caprylic acid/glycerol molar ratio of 4.5:1 and 66.7 °C, a higher yield was reached up to 92.4 %.