Styrene metal-neutralized

Styrene, sulfonated and metal neutralized Single Tg FTIR II had various degrees of sulfonation and neutralized by Na or Li Lu and Weiss (1996b)... 

As shovm in Eq 6 59, Rapoport has prepared sinefungin, nucleoside andbiodcs, via nitro-aldol reaction, dehydradon, and reducdon v/iihZn in acetic acid fi-Niiro styrenes are selecdvity reduced to the corresponding oximes by indium metal in aqueous methanol under neutral conthdons ... 

Polymers can be modified by the introduction of ionic groups [I]. The ionic polymers, also called ionomers, offer great potential in a variety of applications. Ionic rubbers are mostly prepared by metal ion neutralization of acid functionalized rubbers, such as carboxylated styrene-butadiene rubber, carboxylated polybutadiene rubber, and carboxylated nitrile rubber 12-5]. Ionic rubbers under ambient conditions show moderate to high tensile and tear strength and high elongation. The ionic crosslinks are thermolabile and, thus, the materials can be processed just as thermoplastics are processed [6]. 

Weiss et al. [75] have synthesized Na and Zn salt of sulfonated styrene(ethylene-co-butylene)-styrene triblock ionomer. The starting material is a hydrogenated triblock copolymer of styrene and butadiene with a rubber mid-block and PS end-blocks. After hydrogenation, the mid-block is converted to a random copolymer of ethylene and butylene. Ethyl sulfonate is used to sulfonate the block copolymer in 1,2-dichloroethane solution at 50°C using the procedure developed by Makowski et al. [76]. The sulfonic acid form of the functionalized polymer is recovered by steam stripping. The neutralization reaction is carried out in toluene-methanol solution using the appropriate metal hydroxide or acetate. 

A dispersant that can be used in drilling fluids, spacer fluids, cement slurries, completion fluids, and mixtures of drilling fluids and cement slurries controls the rheologic properties of and enhances the filtrate control in these fluids. The dispersant consists of polymers derived from monomeric residues, including low-molecular-weight olefins that may be sulfonated or phosphonated, unsaturated dicarboxylic acids, ethylenically unsaturated anhydrides, unsaturated aliphatic monocarboxylic acids, vinyl alcohols and diols, and sulfonated or phosphonated styrene. The sulfonic acid, phosphonic acid, and carboxylic acid groups on the polymers may be present in neutralized form as alkali metal or ammonium salts [192,193]. 

Preparation and Reactions of S-b-MM. As mentioned in the introduction, we were interested in block copolymers of styrene and alkali metal methacrylates with overall molecular weights of about 20,000 and methacrylate contents on the order of 10 mol%. The preparation of such copolymers by the usual anionic techniques is not feasible. An alternative is to prepare block copolymers of styrene and methacrylic esters by sequential anionic polymerization, followed by a post-polymerization reaction to produce the desired block copolymers. The obvious first choice of methacrylic esters is methyl methacrylate. It is inexpensive, readily available, and its block copolymers with styrene are well-known. In fact, Brown and White have reported the preparation and hydrolyses of a series of S-b-MM copolymers of varying MM content using p-toluenesulfonic acid (TsOH) (6). The resulting methacrylic acid copolymers were easily converted to their sodium carboxylates by neutralization with sodium hydroxide. 

The Ti,Al-Beta shows both acidic and oxidative properties which is reflected in unwanted side-reaction. The group of Corma used the bifunctionality in the epoxidation/rearrangement of cx-terpineol to cineol alcohol and in the formation of furans from linalool.81,82 Similarly van Klaveren et al. applied Ti,Al-Beta in the one-pot conversion of styrene to phenyl acetaldehyde.83 Sato et alM solved the unwanted acid-catalyzed side reaction by neutralizing the acid site by ion exchange with alkali metals. Nevertheless the bifunctionality restricts the use of this catalyst to a limited number of reactions. 

The neutral molecular sieve, aluminum phosphate (ALPO, Chapter 10) can also serve as a shape selective support for metal catalysts. These catalysts are normally prepared by the incipient wetness process followed by appropriate drying and reduction procedures. Fig. 13.19 illustrates the selectivity observed using a Ni/ALPO catalyst to hydrogenate a mixture of styrene and a methyl styrene (Eqn. 13.13). The rates of hydrogenation of cyclic alkenes over a Rh/ALPO catalyst decreased in the order cyclopentene cyclohexene > cycloheptene > cyclooctene but no selectivity was observed in a competitive hydrogenation of a mixture of cyclohexene and cyclooctene. 75... 

Branched acrylic polymers based upon the copolymerization of acrylates and related monomers with methacrylate macromonomers are particularly useful in waterborne coatings. A macromonomer based upon isobutyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate was copolymerized with butyl acrylate, 2-hydroxyethyl acrylate, meth-acrylic acid, methyl methacrylate, and styrene.518 After neutralization with dimethylethanolamine or inorganic bases, the polymer could be cross-linked with melamine resin on a metal surface. These systems may be used for either pigmented layers or clear coats. 

Very recently, an aqueous olefin polymerization using an early transition metal catalyst has also been reported [84]. A toluene solution of styrene is prepolymerized briefly by a catalyst prepared by combination of [(CsMesjTifOMe),] with a borate and an aluminum-alkyl as activators. The reaction mixture is then emulsified in water, where further polymerization occurs to form syndiotactic polystyrene stereoselectively. It is assumed that the catalyst is contained in emulsified droplets and is thus protected from water, with the formation of crystalline polymer enhancing this effect. Cationic or neutral surfactants were found to be suitable, whereas anionic surfactants deactivated the catalyst. The crystalline polystyrene formed was reported to precipitate from the reaction mixture as relatively large particles (500 pm). 

Ionomers of practical interest have been prepared by two synthetic routes (a) copolymerization of a low level of functionalized monomer with an olefinically unsaturated monomer or (b) direct functionalization of a preformed polymer. Typically, carboxyl containing ionomers are obtained by direct copolymerization of acrylic or methacrylic acid with ethylene, styrene and similar comonomers by free radical copoly-merization. Rees (22) has described the preparation of a number of such copolymers. The resulting copolymer is generally available as the free acid which can be neutralized to the degree desired with metal hydroxides, acetates and similar salts. Recently, Weiss et al.(23-26) have described the preparation of sulfonated ionomers by copolymerization of sodium styrene sulfonate with butadiene or styrene. 

Remarkably, catalytic hydroboration of arylethenes (styrenes) using a cationic rhodium complex occurs with unconventional regioselectivity. Essentially complete selectivity for the secondary alcohol (formed after oxidation of the organoborane) is obtained by using the complex [Rh(COD)2]Bp4 in the presence of a phosphine ligand (5.14). This contrasts with that obtained in the absence of a catalyst, or in the presence of neutral transition-metal catalysts. 

The preparation of ionomers involves either the copolymerization of a functionalized monomer with an olefinic unsaturated monomer or direct functionalization of a preformed polymer. Typically, free-radical copolymerization of ethylene, styrene, or other a-olefins with acrylic acid or methacrylic acid results in carboxyl-containing ionomers. The copolymer, available as a free acid, is then neutralized partially to a desired degree with metal hydroxides, acetates, or similar salts. The second route for the preparation of ionomers involves modification of a preformed polymer. For example, sulfonated polystyrene is obtained by direct sulfonation of polystyrene in a homogeneous solution followed by neutralization of the acid to the desired level. Some commercially available ionomers are listed in Table 15.17. 

Chelating resins, styrene-divinylbenzene copolymer, containing iminodiacetate functional groups have been successfully used to preconcentrate transition metal ions from solutions of high salt concentrations. Selective neutral metal chelates have been found to be isolated and recovered using Cjg chemically bonded silica gel (103). We now digress to some of the author s findings in this area. 

Chem. Descrip. Alcohol phosphate, unneutrallzed Uses Internal mold release agent In unsat. polyester resin molding operations and FRP, e.g., metal die, compression, pultrusion corrosion protectant for ferrous metal molds release agent for externally heat-cured molding operations antistat when neutralized lubricant and corrosion inhibitor in oils formulation of textile lubricants and finishes Features Improves surf, appearance of molded parts Properties Pale yel. Ilq. mild fatty alcohol odor sol. In Freon TF, IPA, styrene, toluene, min. oil, kerosene self-dlsp. In water, glycerol Insol. in ethylene glycol sp.gr. 0.98 dens. 8.2 Ib/gal vise. 165 cps decomp. pt. > 175 C flash pt. (PMCC) > 100 C pH 2-3 anionic 100% act. 

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