Macrocyclic oligoesters incorporating a cyclotetrasiloxane ring

Document Type

Article

Publication Date

7-13-2015

Publication Title

Biomacromolecules

Volume

16

Issue

7

First Page

2091

Last Page

2100

Abstract

Macrocyclic oligoester structures based on a cyclotetrasiloxane core consisting of tricyclic (60+ atoms) and pentacycylic (130+ atoms) species were identified as the major components of a lipase-mediated transesterification reaction. Moderately hydrophobic solvents with log P values in the range of 2-3 were more suitable than those at lower or higher log P values. Temperature had little effect on total conversion and yield of the oligoester macrocycles, except when a reaction temperature of 100 °C was employed. At this temperature, the amount of the smaller macrocycle was greatly increased, but at the expense of the larger oligoester. For immobilized lipase B from Candida antarctica (N435), longer chain length esters and diols were more conducive to the synthesis of the macrocycles. Langmuir isotherms indicated that monolayers subjected to multiple compression/expansion cycles exhibited a reversible collapse mechanism different from that expected for linear polysiloxanes.

DOI

10.1021/acs.biomac.5b00518

ISSN

15257797

E-ISSN

15264602

PubMed ID

26061086

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