Vinyl alcohols groups

FIG. 9 XPS analysis of PLA-PEG microparticle surfaces showing the contribution to surface chemistry of the lactic acid, ethylene glycol, and vinyl alcohol groups. (From Ref. 37.)... 

Fig. 12. Lineweaver-Burk plot of the kinetic data of the dextrin hydrolysis in the presence of a copolymer of vinyl alcohol and ethylene sulfonic acid (80 °C). Copolymer contained 1.0 mole % sulfonic groups and 99 mole % vinyl alcohol groups. [Copolymer] = 5.0 x 10" mole 1 Copolymer A No. 3, O No, 5,...

Matsumura S, Shigeno H (1993), Builder performance in detergent formulations and biodegradabiUty of poly(sodimn carboxylate) containing vinyl alcohol groups , J Am Oil Chem Soc, 70, 659-665. 

They are colourless liquids with characteristic odours, and are prepared by the condensation of ketones with alkyl orthoformates in the presence of alcohols, or by the reaction of acetylenes with alcohols in presence of HgO and BF3. In some cases trichloroethanoic acid is used as the catalyst. They lose alcohol when heated and form vinyl ethers. Exchange of alcohol groups occurs when the ketals of the lower alcohols are boiled with alcohols of greater molecular weight. See acetals. 

An sp -sp2 or sp -sp - single bond where the sp atom is in Group VIA (for example, the C-0 bond of vinyl alcohol) has a two fold barrier with an optimal planar configuration described by V2=h-2.0 kcal/mol. 

Acetals are readily formed with alcohols and cycHc acetals with 1,2 and 1,3-diols (19). Furfural reacts with poly(vinyl alcohol) under acid catalysis to effect acetalization of the hydroxyl groups (20,21). Reaction with acetic anhydride under appropriate conditions gives the acylal, furfuryUdene diacetate... 

The properties of these new materials are being studied. Hydroboration is also appHed for the conversion of double bonds in polymers into hydroxyl groups (450—454). Well-defined copolymers of ethylene—vinyl alcohol can be prepared (455). 

The resihency and dyeabihty of poly(vinyl alcohol) fibers is improved by a process incorporating -hydroxybenzaldehyde to provide a site for the formation of a stable Mannich base. Hydroxyl groups on the fiber are converted to acetal groups by -hydroxybenzaldehyde. Subsequent reaction with formaldehyde and ammonia or an alkylamine is rapid and forms a stable Mannich base that is attached to the polymer backbone (94). 

Carbon Cha.in Backbone Polymers. These polymers may be represented by (4) and considered derivatives of polyethylene, where n is the degree of polymeriza tion and R is (an alkyl group or) a functional group hydrogen (polyethylene), methyl (polypropylene), carboxyl (poly(acryhc acid)), chlorine (poly(vinyl chloride)), phenyl (polystyrene) hydroxyl (poly(vinyl alcohol)), ester (poly(vinyl acetate)), nitrile (polyacrylonitrile), vinyl (polybutadiene), etc. The functional groups and the molecular weight of the polymers, control thek properties which vary in hydrophobicity, solubiUty characteristics, glass-transition temperature, and crystallinity. 

Vinyllithium [917-57-7] can be formed direcdy from vinyl chloride by means of a lithium [7439-93-2] dispersion containing 2 wt % sodium [7440-23-5] at 0—10°C. This compound is a reactive intermediate for the formation of vinyl alcohols from aldehydes, vinyl ketones from organic acids, vinyl sulfides from disulfides, and monosubstituted alkenes from organic halides. It can also be converted to vinylcopper [37616-22-1] or divinylcopper lithium [22903-99-7], which can then be used to introduce a vinyl group stereoselectively into a variety of a, P-unsaturated systems (26), or simply add a vinyl group to other a, P-unsaturated compounds to give y, 5-unsaturated compounds. Vinyllithium reagents can also be converted to secondary alcohols with trialkylb o r ane s. 

The hydroxyl groups in poly(vinyl alcohol) contribute to strong hydrogen bonding both intra- and intermolecularly, which reduces solubiUty in water. The presence of the residual acetate groups in partially hydrolyzed poly(vinyl alcohol) weakens these hydrogen bonds and allow solubiUty at lower temperatures. 

Other developments in chelating resins include fibers made from poly(ethylene glycol) and poly(vinyl alcohol) to which EDA was attached with epichl orohydrin (281) and a styrene—divinylbenzene resin with pendant EDTA or DETPA groups (282). 

The use of a catalytic quantity of alkah equivalent to only a small fraction of the acetate has the advantage that contamination of the poly(vinyl alcohol) with salts, which are difficult to remove, is minimized. A variant of the process is the use of a mixture of alcohol with the acetate ester produced by the alcoholysis as the alcoholyzing agent. This provides a means of controlling the completeness of removal of the acetate groups from the poly(vinyl acetate) (111). 

Hydroxyl groups are extremely reactive. These occur attached to the backbone of the cellulose molecule and poly(vinyl alcohol). Chemically modified forms of these materials are dealt with in the appropriate chapters. 

Japanese workers have developed fibres from poly(vinyl alcohol). The polymer is wet spun from warm water into a concentrated aqueous solution of sodium sulphate containing sulphuric acid and formaldehyde, the latter insolubilising the alcohol by formation of formal groups. 

Residual acetate groups, due to incomplete hydrolysis of poly(vinyl acetate) to poly(vinyl alcohol). 

Enols of simple ketones can be generated in high concentration as metastable species by special techniques. Vinyl alcohol, the enol of acetaldehyde, can be generated by very careful hydrolysis of any of several ortho ester derivatives in which the group RC02 is acetate acid or a chlorinated acetate acid. ... 

Vinyl alcohol plastics Group of plastics composed of resins derived from the hydrolysis of polyvinyl esters or copolymers of vinyl esters. 

The non-bonded interaction energy, the van-der-Waals and electrostatic part of the interaction Hamiltonian are best determined by parametrizing a molecular liquid that contains the same chemical groups as the polymers against the experimentally measured thermodynamical and dynamical data, e.g., enthalpy of vaporization, diffusion coefficient, or viscosity. The parameters can then be transferred to polymers, as was done in our case, for instance in polystyrene (from benzene) [19] or poly (vinyl alcohol) (from ethanol) [20,21]. 

FIG. 5 Local concentration profiles around a hydroxyl group in poly(vinyl alcohol) of heavy atoms in a (1 1) water/ethanol mixture A = OW water oxygen, A = OE ethanol oxygen, A = CE ethanol carbon. The local atomic fractions are defined as = a( )/ ZIb where a( ) is average number of atoms... 

Run frequenqf calculations on the two vinyl alcohol isomers we considered in the last chapter. Optimize the structures at the RHF level, using the 6-31G(d) basis set, and perform a frequency calculation on each optimized structure. Are both of the forms minima What effect does the change in structure (i.e., the position of hydrogen in the hydroxyl group) have on the frequencies ... 

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