Copolymeric polythioesters by lipase-catalyzed thioesterification and transthioesterification of α,ω-alkanedithiols
| Autor: | Klaus Bergander, Erika Klein, Kumar D. Mukherjee, Klaus Vosmann, Eberhard Fehling, N. Weber |
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| Rok vydání: | 2006 |
| Předmět: |
Polymers
Triacylglycerol lipase Thio Degree of polymerization Thioester Applied Microbiology and Biotechnology chemistry.chemical_compound Alkanes Polymer chemistry Organic chemistry Sulfhydryl Compounds Lipase Rhizomucor chemistry.chemical_classification Esterification biology Chemistry Esters General Medicine Enzymes Immobilized Monomer Thiolysis Polymerization biology.protein Biotechnology |
| Zdroj: | Applied Microbiology and Biotechnology. 70:290-297 |
| ISSN: | 1432-0614 0175-7598 |
| DOI: | 10.1007/s00253-005-027-5 |
| Popis: | Linear copolymeric polythioesters [PTE; poly(alpha,omega-alkanedioic acid-co-alpha,omega-alkanedithiols)] were formed in good yield (approximately 69%) by thioesterification of 1,12-dodecanedioic acid with 1,6-hexanedithiol and 1,8-octanedithiol, respectively, catalyzed by immobilized lipase from Rhizomucor miehei (Lipozyme RM IM) in vacuo without a solvent. Similarly, transthioesterification (thiolysis) of diethyl 1,12-dodecanedioate with 1,6-hexanedithiol led to the formation of approximately 66% PTE. Poly (1,12-dodecanedioic acid-co-1,6-hexanedithiol) and poly (1,12-dodecanedioic acid-co-1,8-octanedithiol) were extracted from the reaction mixture using methyl-t-butylether, precipitated at -20 degrees C and the precipitates extracted with boiling i-hexane to yield two fractions of PTE. The i-hexane-insoluble fraction of poly (1,12-dodecanedioic acid-co-1,6-hexanedithiol) shows an average molecular mass (Mw) of 1,212 Da, corresponding to a molecular weight range of up to 13,200 Da and a degree of polymerization of up to 38 monomer units. The i-hexane-insoluble fraction of poly (1,12-dodecanedioic acid-co-1,8-octanedithiol) shows a Mw of 2,360 Da, corresponding to a molecular weight range of up to 19,500 Da and a maximum degree of polymerization of up to 52 monomer units. The low-molecular weight (800 Da) reaction products of thioesterification of 1,12-dodecanedioic acid with 1,6-hexanedithiol, elucidated by gas chromatography-mass spectroscopy, show the following intermediates: (1) 9,20-dioxo-1,8-dithiacycloeicosane; (2) 17,28-dioxo-1,8,9,16-tetrathiacyclooctacosane; (3) 1,12-dodecanedioic acid methyl(O)ester 6'-S-mercaptohexyl thio(S)ester; and (4) oligomeric linear thioester, formed by thioesterification of two molecules of 1,12-dodecanedioic acid with one molecule of 1,6-hexanedithiol. |
| Databáze: | OpenAIRE |
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