Ring-opening polymerization of ethylene carbonate: comprehensive structural elucidation by 1D & 2D-NMR techniques, and selectivity analysis
نویسندگان
چکیده
Ring-opening polymerization (ROP) of ethylene carbonate (EC) is associated with the emission of carbon dioxide during polymerization, which results in polymer chains containing ether linkages besides targeted carbonate linkages. In this study, ethylene carbonate is polymerized by ring-opening polymerization in the presence of sodium stannate trihydrate as a heterogeneous transesterification catalyst. Comprehensive structural analysis of the products is conducted by advanced one-dimensional (H & C) and two-dimensional nuclear magnetic resonance (NMR) techniques (COSY, HSQC and HMBC). MALDI-TOF MS analysis is also conducted to support the results obtained by the advanced NMR techniques. Conversion and average ratio of carbonate to ether linkages of the polymer chains are quantified by H-NMR. Molar mass progression is evaluated by size exclusion chromatography. Finally, selectivity of polymerization conditions for molar mass and dispersity, conversion, and average ether content are evaluated by varying the temperature, catalyst content, monomer to initiator ratio and polymerization solvent.
منابع مشابه
Ruthenium Olefin Metathesis Catalysts Bearing Carbohydrate-Based N-Heterocyclic Carbenes.
Ru-based olefin metathesis catalysts containing carbohydrate-derived NHCs from glucose and galactose were synthesized and characterized by NMR spectroscopy. 2D-NMR spectroscopy revealed the presence of Ru-C (benzylidene) rotamers at RT and the rate of rotation was measured using magnetization transfer and VT-NMR spectroscopy. The catalysts were found to be effective at ring-opening metathesis p...
متن کاملAdvanced NMR techniques for structural characterization of heterocyclic structures
H and C NMR spectra remain the first tool used by chemists to perform the structure elucidation of their products on a routine basis. It is common to provide NMR data on both proton and carbon spectra based on one-dimensional experiments. The increasing complexicity of natural compounds and their synthetic related derivatives implies the use of some more recent 1D and 2D NMR techniques. The pur...
متن کاملSynthesis and Thermal Properties of Novel Biodegradable ABCBA Pentablock Copolymers from Poly (Ethylene glycol), L-Lactide and p-Dioxanone
In this work, new biodegradable ABCBA type pentablock copolymers with different mole ratio of L-lactide and PPDO-b-PEG-b-PPDO triblock copolymer were synthesized and characterized. In the first step, PPDO-b-PEG-b-PPDO triblock copolymer was synthesized via a ring-opening polymerization of P-DiOxanone (PDO) monomer with Poly (Ethylene Glycol) (P...
متن کاملRing-opening graft polymerization of propylene carbonate onto xylan in an ionic liquid.
The amidine organocatalyst 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) is an effective nucleophilic catalyst. Biocomposites with tuneable properties were successfully synthesized by ring-opening graft polymerization (ROGP) of propylene carbonate (PC) onto xylan using DBU as a catalyst in the ionic liquid (IL) 1-allyl-3-methylimidazolium chloride ([Amim]Cl). The effects of reaction temperature, rea...
متن کاملReactivity ratios, and mechanistic insight for anionic ring-opening copolymerization of epoxides.
Reactivity ratios were evaluated for anionic ring-opening copolymerizations of ethylene oxide (EO) with either allyl glycidyl ether (AGE) or ethylene glycol vinyl glycidyl ether (EGVGE) using a benzyl alkoxide initiator. The chemical shift for the benzylic protons of the initiator, as measured by (1)H NMR spectroscopy, were observed to be sensitive to the sequence of the first two monomers adde...
متن کامل