Water-Soluble Polymer Alkanals

Preparation of Methoxypolyethylene Glycol-Butyraldehyde Diethyl Acetal 

A mixture consisting of methoxypolyethylene glycol (30,000 daltons 60% solution in toluene 3.30 g), 30ml of toluene, and butylated hydroxytoluene (0.004 g) were azeotropically dried by distilling off toluene under reduced pressure. Dried methoxypolyethylene glycol was then dissolved in 15 ml toluene and treated with 4 ml of l.OM potassium t-butoxide in t-butanol, 4-chloro-butyraldehyde diethyl acetal (0.00277 mol), and potassium bromide (0.05 g). The mixture was stirred overnight 

A mixture of the Step 1 product (1.0 g), 20 ml of deionized water, and 5% phosphoric acid was stirred for 3 hours at ambient temperature and then treated with sodium chloride (l.Og) and sufficient O.IM sodium hydroxide to obtain a pH of 6.8. The product was extracted three times with 20 ml of CH2CI2, dried with MgS04, concentrated, and 82 g of product were isolated. 

Erythropoietin ( 2 mg) was dissolved in 1 ml of 0.1 mM sodium acetate with a pH of 5, and then treated with the Step 2 product (10 mmol) and cyanoborohydride and stirred for 24 hours at 4°C. Confirmation of A-terminal modification was determined by peptide mapping. Increasing the ratio of methoxyPEG-butyraldehyde to eythro-poietin increased the degree of erythropoietin incorporation. 

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PVP is a nonionic water-soluble polymer that interacts with water-soluble dyes to form water-soluble complexes with less fabric substantivity than the free dye. Additionally, PVP inhibits soil redeposition and is particularly effective with synthetic fibers and synthetic cotton blends. The polymer comprises hydrophilic, dipolar imido groups in conjunction with hydrophobic, apolar methylene and methine groups. The combination of dipolar and amphiphilic character make PVP soluble in water and organic solvents such as alcohols and partially halogenated alkanes, and will complex a variety of polarizable and acidic compounds. PVP is particularly effective with blue dyes and not as effective with acid red dyes. 

Polysubstituted thiophenes with other groups different to w-alkyl chain are also known. For example, alkylsulfonate, alkoxy, amide, poly(ether), and acylgroup were introduced in 3-position in thiophene and their electroobtained polymers were studied. A water soluble poly(alkane)sulfonatederivative of thiophene has also been reported [55] which would be an intrinsically conducting polymer (self-doped). Composites of poly(thiophene)s with poly(methylmethacrylate) and poly(vinylchloride) were prepared as... 

Howdle et al. was the first to report on the enzymatic emulsion polymerization of water-soluble acrylamide monomers in a w/c microemulsion [75]. Acrylamide is one of the few monomers that show limited solubility in supercritical C02, and hence was particularly suited to inverse emulsion polymerization [61]. In this report, Howdle et al. showed that the yields and molecular weights obtained via polymerization in C02 are comparable to those generated in a conventional polymerization in an alkane/water medium. Indeed, polymer molecular weights up to 900 kDa were observed when a surfactant was not used and molecular weights around 300 kDa when a perfhiropolyether was used. The generally accepted mechanism for this reaction is shown in Figure 13.5. 

Nonpolar polymers (polyisoprene, polybutadiene) mix infinitely with alkanes (hexane, oetane, ete.) but do not mix with sueh polar liquids as water and aleohols. Polar polymers (eellulose, polyvinylalcohol, ete.) do not mix with alkanes and readily swell in water. Polymers of the average polarity dissolve only in liquids of average polarity. For example, polystyrene is not dissolved or swollen in water and alkanes but it is dissolved in aromatie hydrocarbons (toluene, benzene, xylene), methyl ethyl ketone and some ethers. Polymethylmethacrylate is not dissolved nor swollen in water nor in alkanes but it is dissolved in dichloroethane. Polychloroprene does not dissolve in water, restrictedly swells in gasoline and dissolves in 1,2-dichloroethane and benzene. Solubility of polyvinylchloride was considered in terms of relationship between the size of a solvent molecule and the distance between polar groups in polymer. ... 

Interestingly, these hydrocarboxylation reactions also occur to some extent in metal-free systems, but the reaction efficiency can be improved significantly by the use of metal catalysts or promoters [18]. Among the variety of different transition metal catalysts, multicopper(II) compounds were usually the most active ones [18, 20], leading to product yields that are circa two to five times superior to those in the metal-free systems. The water-soluble tefracopper(II) complex [Cu4(/x4-0)(/u,3-tea)4 ( u,3-BOH)4][BF4]2 (6) was formerly used as a model catalyst in the hydrocarboxylations of C2-Q alkanes [18, 31]. Since then, the reactions have been optimized further [19-21] and extended to other alkanes and multicopper catalysts, namely including the dimer 2 [22], the trimer 5 [13], the tetramer 7 [14], and the polymers 11 [12], 12 [12], 13 [14], and 15 [15] (Table 3.1). Interestingly, in contrast to alkane oxidation, the hydrocarboxylation reactions do not require an acid cocatalyst. 

Nonionic surfactants are surfactants that also contain both a water-soluble group and an oil-soluble group however, they do not ionize. The water-soluble group is usually a polyethylene oxide or a polypropylene polymer. Otherwise, nonionic surfactants include amine oxides and alkanol amine condensates. The oil-soluble end is a long-chain hydrocarbon (alkane). General formulas for the most common nonionic surfactants are as follows ... 

Since hdpe is a linear hydrocarbon polymer and, like linear alkanes, sputters when ignited, it burns readily unless admixed with alumina trihydrate (ATH) or other flame retardants. It has a solubility parameter of 7.9 H and low water absorption (0.01%). 

The relatively large monomer droplets (generally 2-5ym in diameter) have too small a surface area to capture radicals from the aqueous phase and therefore serve as reservoirs for the diffusion of monomer through the aqueous phase to the pol3onerizing oligomeric radicals, micelles, or polymer particles. Despite the unfavorable statistical probabilities, however, some monomer droplets capture radicals and polymerize to form microscopic or near-microscopic particles (14), and some of these particles which are entirely separate from the main particle size distribution are formed in most batch polymerizations. Polymerization in monomer droplets becomes much more significant when the size of the emulsion droplets is decreased. The use of ionic emulsifier-fatty alcohol mixtures (13) and, later, ionic emulsifier-alkane mixtures (15), allows the preparation of 0.1-0.2ym size styrene monomer droplets, which compete favorably with initiation in micelles and in the aqueous phase as the mechanism of particle nucleation. The mechanism of formation of these "mini-emulsions" has been attributed to the very low solubility of the fatty alcohols and alkanes in water (16) or to the formation of crystalline complexes between the ionic emulsifiers and fatty alcohols (17) the two mechanisms are not mutually exclusive. Thus this mechanism pertains only to special systems. 

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