02148nas a2200265   4500008004100000022001400041245010600055210006900161260000900230300001100239490000800250520122800258653002901486653003101515653002401546653001701570653001001587100002601597700002201623700002401645700002401669700003301693700002401726856013201750       2020                        eng d  a0014-305700aRenewing polyethylene: insertion copolymerization of sugar derived hydrophilic monomers with ethylene0 aRenewing polyethylene insertion copolymerization of sugar derive  cJUL   a1097750 v1343 a<p>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'), 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.</p>
10aHydrophilic polyethylene10ainsertion copolymerization10aIsohexide mono-enes10aPolyethylene10aSugar1 aRajput, Bhausaheb, S.1 aPawal, Sandip, B.1 aBodkhe, Dnyaneshwar1 aRao, Nagamalleswara1 aSainath, Annadanam, V. Sesha1 aChikkali, Samir, H.  uhttps://library.ncl.res.in/content/renewing-polyethylene-insertion-copolymerization-sugar-derived-hydrophilic-monomers-ethylene02488nas a2200277   4500008004100000022001400041245010000055210006900155260000800224520154900232653001701781653000801798653003001806653002701836653001701863100002401880700001901904700002101923700002101944700002801965700002201993700002502015700001702040700002402057856012902081       2024                        eng d  a1060-132500aDesigning of imine thiophene-ligated metal-complexes and implication in ethylene polymerization0 aDesigning of imine thiopheneligated metalcomplexes and implicati  cSEP3 a<p>
	Polyethylene is the single largest volume polymer produced globally using Ziegler-type catalysts. Numerous modifications have been reported in search of a better catalyst that can control molecular weight, polydispersity, and branching. In our attempts to identify a suitable imine thiophene-ligated chromium complex, we examined 9 different titanium complexes computationally. The DFT investigations considered barriers for insertion, propagation, and termination by beta-H elimination or chain transfer, and identified N-(4-methoxyphenyl)-2-phenyl-1-(thiophen-2-yl)ethan-1-imine(L9) as the most suitable ligand. Subsequently, L9 was prepared in good yield (70%) by condensing 2-phenyl-1-(thiophen-2-yl)ethan-1-one with 4-methoxyaniline. Ligand L9 was treated with early transition metal precursors (Ti, Cr, Zr) to generate a homogenous catalyst. The identity of these catalysts was unambiguously ascertained using a combination of NMR, ICP, FT-IR, UV-Vis spectroscopy, and ESI-MS. The performance of L9-ligated titanium complex [Cat.1] was examined in ethylene polymerization using MMAO as a co-catalyst. Insertion of ethylene was tracked using high-pressure NMR experiments and Cat.1 was found to be active in the polymerization. Ethylene polymerization conditions were optimized to obtain high activity and molecular weight polyethylene. The chromium complex [Cat.2] outperformed the Ti and Zr-derived catalysts with the highest TOF of 6294 mol of PE/mol of Cr/h. Cat.2 produced high molecular weight, high-density polyethylene.</p>
10aCr-complexes10aDFT10ahigh-density polyethylene10aImine thiophene ligand10aPolyethylene1 aShaikh, Maulali, H.1 aRamekar, Rohan1 aJawoor, Shailaja1 aDash, Soumya, R.1 aBirajadar, Rajkumar, S.1 aPawal, Sandip, B.1 aThenmani, Nandakumar1 aVanka, Kumar1 aChikkali, Samir, H.  uhttps://library.ncl.res.in/content/designing-imine-thiophene-ligated-metal-complexes-and-implication-ethylene-polymerization