Thermal and conductivity properties of poly(ethylene glycol)-based cyclopolymersElectronic supplementary information (ESI) available: 1H NMR spectra and gel permeation chromatography traces of polymers 4, 5a and 6 after purification by precipitation in the non-solvent. See http://www.rsc.org/suppdata/jm/b4/b402677b/

2004 ◽  
Vol 14 (16) ◽  
pp. 2524 ◽  
Author(s):  
Enrique Blazquez ◽  
Piercarlo Mustarelli ◽  
Dario Pasini ◽  
Pier Paolo Righetti ◽  
Corrado Tomasi
Catalysts ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 228 ◽  
Author(s):  
Prajakatta Mulay ◽  
Gayatri Shrikhande ◽  
Judit Puskas

This paper investigates the transesterification of methyl 3-mercaptopropionate (MP-SH) with tetraethylene glycol (TEG) and poly(ethylene glycol)s (PEG)s catalyzed by Candida antarctica Lipase B (CALB) without the use of solvent (in bulk). The progress of the reactions was monitored by 1H-NMR spectroscopy. We found that the reactions proceeded in a step-wise manner, first producing monothiols. TEG-monothiol was obtained in 15 min, while conversion to dithiol took 8 h. Monothiols from PEGs with Mn = 1000 and 2050 g/mol were obtained in 8 and 16 h, respectively. MALDI-ToF mass spectrometry verified the absence of dithiols. The synthesis of dithiols required additional fresh CALB and MP-SH. The structure of the products was confirmed by 1H-NMR and 13C-NMR spectroscopy. Enzyme catalysis was found to be a powerful tool to effectively synthesize thiol-functionalized TEGs and PEGs.


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