Ring-opening polymerisation of beta-butyrolactone catalysed by distannoxane complexes: study of the mechanism.
The mechanism of the ring-opening polymerisation of beta-butyrolactones was studied. The ring-opening polymerisation of BL catatlysed by distannoxane complexes is of a living nature. The polymerisation of racemic BL gave a predominantly syndiotactic P(3HB). The temperature effect on syndiospecificity was used to determine the activation energy (deltaE = Esyndiotactic - Eisotactic) for syndiotactic versus isotactic diad placement. The deltaE value was obtained as -1.49 kcal/mol. The steric control leading to the observed syndiospecificity is due predominantly to diastereomeric interactions between the Sn-coordinated P(3HB) chain end. having a specific chain end stereochemistry, and the incoming BL enantiomeric monomers. The catalytic cycle derived from the mechanism of the polymerisation was proposed.
Central Research Laboratory, Takasago International Corporation, Hiratsuka-City, Kanagawa, Japan.
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Hori
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Hagiwara
D015107:4-Butyrolactone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000378:metabolism; D001704:Biopolymers / Q000096:biosynthesis; D006885:Hydroxybutyrates / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D007536:Isomerism; D007700:Kinetics; D008968:Molecular Conformation; D015394:Molecular Structure; D011091:Polyesters / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism; D000094122:Polyhydroxybutyrates
D015107:4-Butyrolactone; D001704:Biopolymers; D006885:Hydroxybutyrates; D011091:Polyesters; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates; C013426:beta-butyrolactone