Macrocyclic oligoesters incorporating a cyclotetrasiloxane ring
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...
| Published in: | Biomacromolecules |
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| Main Authors: | , , , , |
| Format: | Text |
| Language: | unknown |
| Published: |
Scholarship at UWindsor
2015
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| Subjects: | |
| Online Access: | https://scholar.uwindsor.ca/chemistrybiochemistrypub/309 https://doi.org/10.1021/acs.biomac.5b00518 |
| Summary: | 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. |
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