Enzymatic and chemoenzymatic syntheses of biodegradable aromatic polymers효소적 방법과 효소화학적 방법을 통한 생분해성 방향족 고분자의 합성

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Diversified studies on enzymatic and chemoenzymatic syntheses of biodegradable aromatic polymers have been conducted in this study. Lipases and proteases from various sources were tested for the synthesis of aromatic polyesters in organic solvents. A commercial protease from $Bacillus$ $licheniformis$, Optimase M-440, efficiently catalyzed the transesterification of diester of terephthalic acid and 1,4-butanediol in anhydrous tetrahydrofuran (THF). This protease was used as a catalyst in the synthesis of aromatic polyesters in THF. Oligomers with average molecular weights from 400 to 1000 daltons were obtained using various diols and aromatic diesters. The reactions of different types of aromatic ester (aromatic esters with different types of leaving group or isomers of terephthalic acid derivatives) were investigated with model alcohols, n-butanol or 1,4-butanediol. The time course of inactivation of Optimase M-440 was also investigated. Using the same enzyme, enzymatic polytransesterification of aromatic diols was carried out in anhydrous organic solvents. Optimase M-440 also catalyzed the polytransesterification of a diester of glutaric acid with aromatic diols such as benzenedimethanol. Hydrophilic solvents such as pyridine and acetone gave encouraging results in the reaction and the highest reaction rate was observed with pyridine. The Mw of the aromatic polyesters determined by gel permeation chromatography (GPC) was 400-1400 daltons. Bis(2,2,2-trifluoroethyl) glutarate and 1,4-benzenedimethanol were used as model compounds to study the influence of aromaticity, water content and alcoholic leaving group. Enzymatic regioselective acylation of sugars offers an alternative to the poor selectivity of chemical synthesis and enzymatic acylation was carried out for sucrose with TFE-terephthalate in pyridine by employing the same enzyme. Upon increasing the reaction temperature from 27 to $50\,^\circ\!C$, the conversion of sucrose after 24 hours increased from 65...
Advisors
Chang, Ho-Namresearcher장호남researcher
Description
한국과학기술원 : 화학공학과,
Publisher
한국과학기술원
Issue Date
1996
Identifier
106198/325007 / 000905218
Language
eng
Description

학위논문(박사) - 한국과학기술원 : 화학공학과, 1996.2, [ xiii, 105 p. ]

Keywords

Biodegradable Polymer; Protease; Enzymatic Synthesis; Transesterification; 방향족 고분자; 생분해성 고분자; 프로테아제; 효소적 합성; Sugar Acylation

URI
http://hdl.handle.net/10203/28726
Link
http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=106198&flag=dissertation
Appears in Collection
CBE-Theses_Ph.D.(박사논문)
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