Topic
Vinyl acetate
About: Vinyl acetate is a research topic. Over the lifetime, 15970 publications have been published within this topic receiving 162142 citations. The topic is also known as: Ethenyl acetate & Ethenyl ethanoate.
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TL;DR: First principles density functional theory is used to investigate the chain propagation steps for polymerization of polar monomers and finds 2,1-insertion is favored in each case, resulting in a product with a strong interaction of the polar group for the growing polymer chain with the metal.
Abstract: Taking Pd di-imine catalysts as an example, we use first principles density functional theory (B3LYP/6-31G*) to investigate the chain propagation steps for polymerization of polar monomers. We start with the complex formed from insertion of ethylene into the polymer chain and consider insertion into the Pd−C bond for each of four polar monomers: methyl acrylate, vinyl acetate, vinyl chloride, and acrylonitrile. We find 2,1-insertion is favored in each case (by 3 to 5 kcal/mol), resulting in a product with a strong interaction of the polar group for the growing polymer chain with the metal. Next, we insert another unit of the same polar monomer or an ethylene unit (except for acrylonitrile). We optimize the structures for all important intermediates and transition states using a continuum dielectric to account for solvation effects. These studies pinpoint the critical difficulties in designing catalysts to polymerize polar monomers.
71 citations
TL;DR: In this paper, an alcoholic hydroxyl or diol group was introduced into a porous polyethylene hollow fiber membrane by radiation-induced grafting of vinyl acetate (VAc) or glycidyl methacrylate (GMA) followed by saponification or acid hydrolysis.
71 citations
Patent•
3M1
TL;DR: Tamper-resistant inner seals that bond firmly to the lips of lidded and capped glass and plastic containers have been proposed in this paper, where the inner seal incorporates a metallic foil having a heat-sealable adhesive applied to one surface thereof.
Abstract: Tamper-resistant inner seals that bond firmly to the lips of lidded and capped glass and plastic containers The innerseals incorporate a metallic foil having a heat-sealable adhesive applied to one surface thereof The heat-sealable adhesive comprises a paraffin wax or blend of paraffin wax and microcrystalline wax, polystyrene or derivative thereof, rosin or derivative thereof, and at least one high molecular weight polymeric material selected from the group consisting of ethylene/acrylic acid copolymers, ethylene/vinyl acetate copolymers, ethylene/methacrylate copolymers, and ethylene/vinyl acetate/methacrylic acid terpolymers, and blends thereof
71 citations
TL;DR: An efficient lipase-catalyzed conversion of sophorolipid ethyl ester to 6'-monoacylated derivatives and regioselective monoacylation of an amide derivative at the 6'- and 6' '-positions using Novozym 435 and Lipase PS-C are described.
Abstract: Novel enzyme-mediated synthetic routes were developed to provide a new family of sophorolipid derivatives and glycolopid-based amphiphilic monomers. These compounds are of great interest for their potential use in immunoregulation, as well as for other biological properties. In the present work, an efficient lipase-catalyzed conversion of sophorolipid ethyl ester to (a) the 6'-monoacylated derivatives using Novozym 435, (b) 6' '-monoacylated derivatives using Lipase PS-C, (c) secondary amide derivatives using Novozym 435, and (d) 6',6' '-diacylated amide derivatives using Novozym 435 in an one-pot reaction and (e) the regioselective monoacylation of an amide derivative at the 6'- and 6' '-positions using Novozym 435 and Lipase PS-C, respectively, are described. The ethyl ester produced by esterification of the sophorolipid mixture with sodium ethoxide was subjected to acylation catalyzed by Novozym 435 in dry tetrahedrofuran (THF) with vinyl acetate and vinyl methacrylate to produce 6'-monoacylated derivatives. In contrast, Lipase PS-C catalyzed acylations of sophorolipid ethyl ester in dry THF with vinyl acetate and vinyl methacrylate to give the corresponding 6'-monoacylated derivatives. Novozym 435 mediated amidation of sophorolipid ethyl ester in dry THF with phenethylamine, tyramine, p-methoxyphenethylamine, 2-(p-tolyl)ethylamine, and p-fluorophenethylamine generated the corresponding secondary amides but not tertiary amides. The formation of diacyl derivatives of amides was achieved by their treatment with vinyl acetate and vinyl methacrylate in dry THF using Novozym 435 as catalyst. The conversion of sophorolipid ethyl ester to the same diacyl derivatives of amide (i.e., both amidation and acylation) in high yield was also demonstrated in dry THF by a one-pot reaction using Novozym 435. Furthermore, regioselective monoacylation of a sophorolipid amide at 6' and 6' ' in dry THF with vinyl acetate and vinyl methacrylate using Novozym 435 and Lipase PS-C was also demonstrated.
70 citations
TL;DR: In this article, the effect of the purity of CDB on the rate of polymerization was determined, and it was shown that possible byproducts from the synthesis of xanthate reversible addition-fragmentation chain transfer (RAFT) polymerization agents produced an inhibition period in the polymerization of vinyl acetate.
Abstract: The effect of the purity of cumyl dithiobenzoate (CDB) on the rate of polymerization was determined. It was shown that possible byproducts from the synthesis of xanthate reversible addition-fragmentation chain transfer (RAFT) polymerization agents produced an inhibition period in the polymerization of vinyl acetate. The results show that the impurities in cumyl dithiobenzoate act to inhibit or retard the polymerization of 2-hydroxyethyl methacrylate (HEMA), styrene, and MA. The addition of the starting agent DTBA also acts to inhibit the polymerization.
70 citations