3236-48-4Relevant articles and documents
Calculation of hydrolytic rate constants of poly(ortho ester)s from molecular weights determined by gel permeation chromatography
Shih
, p. 2041 - 2048 (1995)
Purpose. To obtained rate constants from weight-averaged (M(w)) or z-averaged (M(z)) molecular weights for polymers of Schule-Flory distribution and undergoing random scission. These constants were compared with those obtained by parallel 1HNMR studies. Methods. The hydrolysis of two poly(ortho ester)s were followed by 1HNMR and gel permeation chromatography (GPC). Results. Equations to convert number-averaged (M(n)), M(w) and M(z) into fraction of backbone remaining (f(c)) were derived. First-order hydrolytic rate constants of two poly(ortho ester)s; DETOSU-HD and DETOSU-CDM were calculated using these relationships. The rate constants calculated from 1HNMR, M(z) and M(w) were 0.215, 0.218 and 0.182 hr-1, respectively, for DETOSU-CDM and 0.152, 0.086 and 0.038 hr-1 for DETOSU-HD. The large discrepancy in the rates determined by 1HNMR and GPC in the latter case was attributed to that the detector response (refractive index) of the monomers was lower than that of the high molecular weight polymer. The difference is small in the case of DETOSU-CDM, and the rates calculated from GPC data were comparable or nearly identical to that obtained from 1HNMR data. Conclusions. Although GPC can yield rapid and valuable kinetic data for the degradation of biodegradable polymers, the system, however, must be carefully calibrated to account for the variations in Mark-Houwink coefficients and in the response of the mass detector between the high and low MW polymers.
Production of Copolyester Monomers from Plant-Based Acrylate and Acetaldehyde
Yuan, Lin,Hu, Yancheng,Zhao, Zhitong,Li, Guangyi,Wang, Aiqin,Cong, Yu,Wang, Feng,Zhang, Tao,Li, Ning
supporting information, (2021/12/14)
PCTA is an important copolyester that has been widely used in our daily necessities. Currently, its monomers are industrially produced from petroleum-derived xylene. To reduce the reliance on fossil energy, we herein disclose an alternative route to acces
Synthesis of 1,4-Cyclohexanedimethanol, 1,4-Cyclohexanedicarboxylic Acid and 1,2-Cyclohexanedicarboxylates from Formaldehyde, Crotonaldehyde and Acrylate/Fumarate
Hu, Yancheng,Zhao, Zhitong,Liu, Yanting,Li, Guangyi,Wang, Aiqin,Cong, Yu,Zhang, Tao,Wang, Feng,Li, Ning
supporting information, p. 6901 - 6905 (2018/06/04)
Valuable polyester monomers and plasticizers—1,4-cyclohexanedimethanol (CHDM), 1,4-cyclohexanedicarboxylic acid (CHDA), and 1,2-cyclohexanedicarboxylates—have been prepared by a new strategy. The synthetic processes involve a proline-catalyzed formal [3+1+2] cycloaddition of formaldehyde, crotonaldehyde, and acrylate (or fumarate). CHDM is produced after a subsequent hydrogenation step over a commercially available Cu/Zn/Al catalyst and a one-pot hydrogenation/oxidation/hydrolysis process yields CHDA, whereas 1,2-cyclohexanedicarboxylate is obtained by a Pd/C-catalyzed tandem decarbonylation/hydrogenation step.