Poly-alcohols methanes

The bis(pyrazolyl)silanes Bps (Scheme 24) were readily prepared from the reaction of Me2SiCl2 and two molar equivalents of the corresponding alkali metal pyrazolates.262 Both Bps and BpsMe2 ligands were isolated in excellent yield. They are stable in dry air for at least six months and soluble in aliphatic and aromatic hydrocarbons, acetonitrile, dichloromethane and ethers. However, they slowly decompose in acetone or in the presence of solvents with acidic protons such as water and alcohols, an important difference with respect to the analogous poly(pyrazolyl)methane ligands. Both bidentate ligands have been used to prepare zinc(II) derivatives. 

Resins formed from the reaction of poly(vinyl alcohol) with aldehydes. The formal derivative (from methanal) is used in wire coatings and adhesives and the bulyral (from butanal) is used in metal paints, wood-sealers, adhesives and in safety glass interlayers. 

Preparation of poly(vinyl alcohol-bis(allyloxy)methane)-poly(vinyl alcohol)... 

More than two-thirds of the benzyl chloride produced is used in the manufacture of butyl benzy l phthalate, a plasticizer used extensively in vinyl flooring and other flexible poly(vinyl chloride) uses such as food packaging. Other significant uses are the manufacture of benzy l alcohol and benzyl chloride-derived quaternary ammonium compounds, each of which consumes more than 10% of the benzyl chloride produced. In the dye industry, benzyl chloride is used as an intermediate in the manufacture of triphenyl-methane dyes. Derivatives of benzyl chloride are processed further to pharmaceutical, perfume and flavour products (Lin Bieron, 1993). 

As is showm in Figure 2, methane is formed over nickel and ruthenium catalysts, especially at low pressures (atmospheric up to 10 bar) and elevated temperatures. Paraffins and olefins are produced over nickel and cobalt catalysis at mild temperatures (< 200 0) and pressures of I -10 bar. With iron catalysts, olefins,parafllns.and minor amounts of alcohols are formed at medium pressures (10 100 bar) and temperatures of 210--340 C. Ruthenium catalysts give, at elevated pressures (150-1000 bar) and low temperatures (100-180 C), poly methylene with a molecular weiglii of up to I 000000. This polymer has similar properties as Ziegler-type low pressure polyethylene. 

Fig. 26. Photo-effects on water permeation through a porous poly(vinj4 alcohol) gel with tri dmiyl-methane leucocyanide groups (content, 1.9 mol %). ( ) an unmodified membrane ( ) a coated membrane in the dark (O) a coated membraw under UV irradiation...

Differently from poly(vinyl alcohol), which does not appear to lose easily the water molecule from the monomer unit, methanol is more easily eliminated from poly(vinyl methyl ether). Some hydrogen migration also takes place in this pyrolysis, methane and some aromatic hydrocarbons being produced. 

The chlorinated alkanes have proven useful for solubilizing lower molecular weight polymers and oligomers. As detailed in the alkane and alcohol chapters, dichloro-methane (DCM) has been used in conjunction with methanol and heptane gradients for the characterization of polystyrenes [272] and styrene/ethyl methacrylate copolymers [649] and with heptane for co-poly (styrene/acrylonitrile) materials [244, 527]. 

For the first, diisocyanates, such as 4,4 -diphenyl methane diisocyanate, 1,6-hexamethylene diisocyanate and toluene diisocyanate were allowed, as an example, to react with metribuzin to yield a pesticide-isocyanate adduct. This was then allowed to react with poly(vinyl alcohol) to form a copolymer with controlled release properties. (See Equation 4.) Crosslinked systems were also made by using an excess of the diisocyanate prior to the reaction with polyvinyl alcohol. The metribuzin was released faster from the linear preparation than the crosslinked due to its ability to swell with the hydrophilic polymer hydrolysis and diffusion of the herbicide occurred more easily. Only the hydrolyzed or released metribuzin moved the polymer remained immobile. The commercial formulation of metribuzin was found to be non-toxic after 78 days, but the linear polymer version was found to retain activity even after 112 days. Polymer crosslinking can be varied to provide even longer activity times. 

A more compact reactor design takes advantage of solid polymer electrolytes (SPEs). Hence, cast Nafion membrane and SPEEK were prepared, and used as cationic SPE whereas alkali-doped poly (vinyl alcohol), PVA and Amberlyst resin composites were made, and used as anionic SPE. These SPEs were combined with a cathode made of copper, electrodeposited onto porous carbon paper, and an anode consisting of Pt/C on the carbon paper. The main electroreduction products were formic acid, methanol, formaldehyde, carbon monoxide and methane, while undesired hydrogen gas by-product was also detected [120]. 

Many linear poly(amido-amines) are water soluble. They are also soluble in several organic solvents, such as chloroform, dichloro-methane, and lower alcohols. 

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