Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Enzymic adipate oligomers

Enzymic Degradation of Ethylene Glycol Adipate Oligomers at the Air-Water Interface... [Pg.216]

The present work investigates the action of pancreatic lipase on spread monolayers of ethylene glycol adipate oligomers. The tritiated hydrolysis products of the uniformly labeled substrate escape into the subphase. Surface radioactivity measurements allow us to determine the substrate concentration at the interface (2, 3) and the extent of the enzymic reaction. The kinetics were investigated as a function of subphase pH and temperature and substrate length and concentration. By... [Pg.217]

Enzymes can be used to selectively hydrolyze only one of two ester groups in a molecule. An esterase from Pseudomonas putida was used to hydrolyze dimethyl adipate to more that 99% half ester.198 Pig liver esterase was used to hydrolyze dialkyl phthalates to the monoesters in 84-93% yields in 1-13 h.199 A porcine pancreatic lipase was used to hydrolyze linear diol diacetates to the monoacetates in 79-95% yields.200 Esters have been prepared from 12-hydroxystearic acid and C8-C18 alcohols in 82-90% yields without esterification of the 12-hydroxy group, by using an immobilized lipase from Rhizomucor miehei.201 Ricinoleic acid, which differs only by having a cis 9 double bond, formed oligomers with an immobilized lipase from C. rugosa.202 These were much less colored than the ones made by the commercial process, which is done at 200 C. [Pg.252]

Rizzarelli et al. [23] synthesized a series of copolymers with units of butylene succinate (BSu) and butylene adipate (BA) with different composition. The copolymers were subjected to enzymatic hydrolysis by lipase (actually two different lipase enzymes, obtained from Mucor miehei or from Rhizopus arrhizus). The degradation products were water soluble. Thus, they were injected in an LC apparatus (the column was a Cl 8) coupled with an ESI-MS. The LC trace displayed more than 20 peaks that were easily identified using MS. These are due to the monomers (BSu and BA), the dimers, the trimers, and the tetramers. LC peaks due to the oligomers rich in BA (e.g., BA3) are weak. On the other hand, LC peaks due to the oligomers rich in BSu (e.g.,BSus) are strong. The results indicate a preferential hydrolytic cleavage. In particular, succinic ester bonds are hydrolyzed faster than adipic ester bonds in BSu-BA copolyesters. [Pg.1082]

A) and butane-1,4-diol (B), after 4 hours a predominant amount of hydroxy terminated oligomers BAB and B(AB)2as well as butanediol and adipic acid (insoluble) were observed. The proposed oligomerisation process pathway was that adipic acid (A) acylates the enzyme the acyl-enzyme complex is attacked by butane-1,4-diol (B) releasing AB. AB then acylates the enzyme via the acid terminus and the enzyme-AB complex is attacked by B to give BAB which does not react with the enzyme but, in due course, attacks an enzyme-AB complex to give B(AB)2. The continuation of this cycle gives B(AB) . Kobayashi and co-workers [24-26] reported the dehydration polymerisation of diacids and diols to form polyester in water with use of lipase catalysts. [Pg.394]


See other pages where Enzymic adipate oligomers is mentioned: [Pg.216]    [Pg.224]    [Pg.136]    [Pg.148]    [Pg.102]    [Pg.247]    [Pg.249]    [Pg.85]    [Pg.328]    [Pg.24]    [Pg.178]    [Pg.876]    [Pg.180]    [Pg.249]   
See also in sourсe #XX -- [ Pg.207 ]




SEARCH



ADIPATE

© 2024 chempedia.info