@article {46797, title = {Renewing polyethylene: insertion copolymerization of sugar derived hydrophilic monomers with ethylene}, journal = {European Polymer Journal}, volume = {134}, year = {2020}, month = {JUL }, pages = {109775}, type = {Article}, abstract = {

Although highly desirable, insertion copolymerization of renewable resource derived functional olefins with ethylene has been rarely investigated. Herein, we report insertion copolymerization of challenging sugar derived isohexide mono-enes with ethylene in the presence of Pd-phosphinesulfonate acetonitrile catalyst (C1). Thus, copolymerization of ethylene with isomannide mono-ene (2a), isosorbide mono-ene (2b{\textquoteright}), isoidide mono-ene (2c) and methacryl-2,3,4,6-tetra-O-acetyl-D glucopyranoside (2d) afforded corresponding functionalized polyethylene (P2a-1 to P2d-1). High temperature proton NMR investigations revealed enchainment of 2a-2c in polyethylene backbone and the highest incorporation of 1.45\% was observed for 2c. The high temperature proton NMR results were further corroborated by solid state C-13 NMR and IR spectroscopy. Gel permeation chromatography analysis displayed weight average molecular weight in the range of 13.0-27.2 x 10(3) g/mol. The thus prepared copolymers revealed melting temperature in the range of 117-126 degrees C. Relatively reduced melting temperature compared to neat polyethylene may suggest an irregular arrangement of pendant functional group on polyethylene main chain.

}, keywords = {Hydrophilic polyethylene, insertion copolymerization, Isohexide mono-enes, Polyethylene, Sugar}, issn = {0014-3057}, doi = {10.1016/j.eurpolymj.2020.109775}, author = {Rajput, Bhausaheb S. and Pawal, Sandip B. and Bodkhe, V. Dnyaneshwar and Rao, I. Nagamalleswara and Sainath, Annadanam V. Sesha and Chikkali, Samir H.} } @article {47439, title = {Elucidating the effect of solid base on the hydrogenation of C5 and C6 sugars over Pt{\textendash}Sn bimetallic catalyst at room temperature}, journal = {Carbohydrate Research}, volume = {505}, year = {2021}, month = {JUL}, pages = {108341}, type = {Article}, abstract = {

Conversion of sugars into\ sugar alcohols\ at room temperature with exceedingly high yields are achieved over Pt{\textendash}Sn/γ-Al2O3\ catalyst in the presence of calcined\ hydrotalcite. pH of the reaction mixture significantly affects the conversion and selectivity for sugar alcohols. Selection of a suitable base is the key to achieve optimum yields. Various solid bases in combination with Pt{\textendash}Sn/γ-Al2O3\ catalysts were evaluated for hydrogenation of sugars. Amongst all combinations, the mixture (1:1\ wt/wt) of Pt{\textendash}Sn/γ-Al2O3\ and calcined hydrotalcite showed the best results. Hydrotalcite helps to make the pH of reaction mixture alkaline at which sugar molecules undergo ring opening. The sugar molecule in open chain form has\ carbonyl group\ which can be polarized by Sn in Pt{\textendash}Sn/γ-Al2O3\ and Pt facilitates the hydrogenation. In the current work, effect of both; solid base and Sn as a promoter has been studied to improve the yields of sugar alcohols from various C5 and C6 sugars at very mild reaction conditions.

}, keywords = {Bimetallic catalyst, Hydrogenation, Hydrotalcites, Sugar, Sugar alcohols}, issn = {0008-6215}, doi = {10.1016/j.carres.2021.108341}, author = {Tathod, Anup P. and Dhepe, Paresh L.} }