Copolymer with sodium 2

The rate of hydrolysis of acrylamide in copolymers with sodium acrylate or AMPS, 2-acrylamido-2-methylpropanesulfonic acid, decreased as the proportion of the anionic comonomers was increased. This effect was much more marked with AMPS than with sodium acrylate, and occurred at 90°, 108°, and 120°C. Typical results at 108°C [Figs. 1 and 2] show the increase in carboxylate content of acrylamide copolymers containing sodium acrylate and AMPS respectively. 

RAFT has also been used to produce graft polymers. The grafting from method is achieved by reacting a halogen-containing polymer such as styrene p-chloromethy I styrene copolymer with sodium dithiohenzoate to obtain a polymeric dithioester, which is an initiator in RAFT polymerization (Sec. 3-15d) [Quinn et al., 2002]. 

The support originally used for solid-phase synthesis was partially chloromethy-lated cross-linked polystyrene, which was prepared by chloromethylation of cross-linked polystyrene with chloromethyl methyl ether and tin(IV) chloride [1-3] or zinc chloride [4] (Figure 6.1). Haloalkylations of this type are usually only used for the functionalization of supports, and not for selective transformation of support-bound intermediates. Because of the mutagenicity of a-haloethers, other methods have been developed for the preparation of chloromethyl polystyrene. These include the chlorination of methoxymethyl polystyrene (Figure 6.1 [5]), the use of a mixture of dimethoxymethane, sulfuryl chloride, and chlorosulfonic acid instead of chloromethyl methyl ether [6], the chlorination of hydroxymethyl polystyrene [7], and the chlorination of cross-linked 4-methylstyrene-styrene copolymer with sodium hypochlorite [8], sulfuryl chloride [8], or cobalt(III) acetate/lithium chloride [9] (Figure 6.1, Table 6.1). 

Within the scope of the original definition, a very wide variety of ionomers can be obtained by the introduction of acidic groups at molar concentrations below 10% into the important addition polymer families, followed by partial neutralization with metal cations or amines. Extensive studies have been reported, and useful reviews of the polymers have appeared (3—8). Despite the broad scope of the field and the unusual property combinations obtainable, commercial exploitation has been confined mainly to the original family based on ethylene copolymers. The reasons for this situation have been discussed (9). Within certain industries, such as flexible packaging, the word ionomer is understood to mean a copolymer of ethylene with methacrylic or acryhc acid, partly neutralized with sodium or zinc. 

Ionomer resins consisting of ethylene—methacrylic acid copolymers partially neutralized with sodium or zinc were commercially introduced in 1964 by Du Pont under the Sudyn trademark (1). More recently, a similar line of products, sold as Hi-Mdan resins, has been commercialized by Mitsui—Du Pont in Japan. lolon ionomeric resins, based on ethylene—acrylic acid, are produced by Exxon in Belgium. Ionomers containing about 1 mol % of carboxylate groups are offered by BP in Europe as Novex resins. Low molecular weight, waxy Aclyn ionomers are produced and sold by AHiedSignal. 

Copolymers of sodium acrylate with sodium 2-acrylamido-2-methylpropane sulfonate (AMPS) or /V, /V- dim ethyl acryl am i de (52) have been used to prepare cross-linked systems at high temperatures and salinity. Chromium cross-linked gels, prepared from a 3 1 blend of partially hydrolyzed... 

For copolymers of acrylamide with sodium acrylate, the preexponential factor K and exponent a of [tj] = KM depend on copolymer composition (Table 3). 

Table 3 Dependence of Constants K and a of [T7] = KM° on Mole Fraction of Sodium Acrylate (Xsa) for Copolymer Acrylamide with Sodium Acrylate in 0.5 M NaCl at 25°C [9]...

Unsymmetrical as well as symmetrical anhydrides are often prepared by the treatment of an acyl halide with a carboxylic acid salt. The compound C0CI2 has been used as a catalyst. If a metallic salt is used, Na , K , or Ag are the most common cations, but more often pyridine or another tertiary amine is added to the free acid and the salt thus formed is treated with the acyl halide. Mixed formic anhydrides are prepared from sodium formate and an aryl halide, by use of a solid-phase copolymer of pyridine-l-oxide. Symmetrical anhydrides can be prepared by reaction of the acyl halide with aqueous NaOH or NaHCOa under phase-transfer conditions, or with sodium bicarbonate with ultrasound. 

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. 

Poly(silylene) polymers are usually made by the reaction of diorganodichlorosilanes with sodium metal, in an inert diluent at temperatures above 100°C. (11.) Rapid stirring is ordinarily used so that the sodium is finely dispersed, speeding the rate of reaction. Either homopolymers or copolymers can be synthesized ... 

Acrylamide copolymers designed to reduce undesired amide group hydrolysis, increase thermal stability, and improve solubility in saline media have been synthesized and studied for EOR applications. These polymers still tend to be shear sensitive. Acrylamide comonomers that have been used include 2-acrylamido-2-methylpropane sulfonate, abbreviated AMPS, (1,321-324), 2-sulfo-ethylmethacrylate (325,326), diacetone acrylamide (324, 326), and vinylpyrrolidinone (327,328). Acrylamide terpolymers include those with sodium acrylate and acrylamido-N-dodecyl-N-butyl sulfonate (329), with AMPS and N,N-dimethylacrylamide (330), with AMPS and N-vinylpyrrolidinone (331), and with sodium acrylate and sodium methacrylate (332). While most copolymers tested have been random copolymers, block copolymers of acrylamide and AMPS also have utility in this application (333). 

Materials. Monomers used in the preparation of the copolymers were as follows acrylamide as a 50% solution in water, stablized with cupric ion, supplied by American Cyanamid Company acrylic acid supplied by BASF and AMPS, 2-acrylamido-2-methylpropanesulfonic acid, (recrystallized grade) obtained from Lubrizol. The sodium salts of acrylic acid and AMPS were prepared by gradual neutralization of the monomers with sodium hydroxide solution, maintaining a temperature of 0 to 5°C, to give a final concentration of 50%. 

The composition and concentration of polymers in the test solutions for hydrolysis are shown in Table 1. The concentration of the sodium acrylate and sodium AMPS copolymers with acrylamide were calculated to provide 0.025 molar solutions of amide units, to simplify the kinetics. 

Poly(starch-g-(1-amidoethylene)) copolymers can be formed by ceric-ion- initiated, free-radical polymerization of 2-propenamide on starch. Poly(starch- g-[partially hydrolyzed 1-amidoethylene]) can be formed by treatment of an aqueous solution of the copolymer with 0.5 M sodium hydroxide at 40UC under anaerobic conditions. Treatment of the copolymer under these conditions for 10 minutes produces a hydrolyzed copolymer with a degree of hydrolysis between 9 5 and 14 5 percent. 

The oxocarbenium perchlorate C(CH20CH2CH2C0+C104 )4 was employed as a tetrafunctional initiator for the synthesis of PTHF 4-arm stars [146]. The living ends were subsequently reacted either with sodium bromoacetate or bromoisobutyryl chloride. The end-capping reaction was not efficient in the first case (lower than 45%). Therefore, the second procedure was the method of choice for the synthesis of the bromoisobutyryl star-shaped macroinitiators. In the presence of CuCl/bpy the ATRP of styrene was initiated in bulk, leading to the formation of (PTHF-fc-PS)4 star-block copolymers. Further addition of MMA provided the (PTHF-fr-PS-fc-PMMA)4 star-block terpolymers. Relatively narrow molecular weight distributions were obtained with this synthetic procedure. 

Benzenetricarbonyl trichloride and l,2,4,5-tetrakis(bromomethyl) benzene were employed as multifunctional initiators for the synthesis of 3-and 4-arm PTHF stars, respectively [147]. The living ends were reacted with sodium 2-bromoisobutyrate followed by reduction with Sml2. The samarium enolates, thus formed were efficient initiators for the polymerization of MMA to give the (PTHF-fo-PMMA) , n = 3 or 4 star-block copolymers, according to Scheme 71. 

Another route to the formation of a hydrazide on a surface is to use an aldehyde-containing particle (such as HEMA/acrolein copolymers) and subsequently modify the aldehydes to form hydrazone linkages with bis-hydrazide compounds, which then can be stabilized by reduction with sodium cyanoborohydride (Chapter 2, Section 5). The resulting derivative contains terminal hydrazides for immobilization of carbonyl ligands (see Figure 14.18). 

Buna [Butadien natrium] The name has been used for the product, the process, and the company VEB Chemische Werke Buna. A process for making a range of synthetic rubbers from butadiene, developed by IG Farbenindustrie in Leverkusen, Germany, in the late 1920s. Sodium was used initially as the polymerization catalyst, hence the name. Buna S was a copolymer of butadiene with styrene Buna N a copolymer with acrylonitrile. The product was first introduced to the pubhc at the Berlin Motor Show in 1936. Today, the trade name Buna CB is used for a polybutadiene rubber made by Bunawerke Hiils using a Ziegler-Natta type process. German Patent 570, 980. 

The mash from the Streptomyces aureofaciens fermentation broth is acidified and filtered. The filtrate is adjusted to the desired pH, usually 7-8.5, and various flocculating or chelating agents may be added (e.g., vinyl acetate-maleic anhydride copolymer, sodium EDTA, ammonium oxalate, Arquad). The precipitate is (1) stirred with filter aid, filtered, stirred with HC1, refiltered, mixed with 2-ethoxyethanol, filtered, washed, and the filtrates are combined, acidified with HC1, NaCl is added, and the crystals are collected, washed with 2-ethoxyethanol, water, and ethanol, and dried (67), or (2) extracted into methyl isobutyl ketone, the extracts are combined, filtered, and acidified with HC1, and the crystals are collected and washed with water, 2-ethoxyethanol, and isopropanol, and vacuum-dried. If the crystals are greenish, they are treated with sodium hydrosulfite at pH 1.8, filtered, washed, and dried as in (1) above (68). 

In an extension of this work, the reuse of the polymeric catalyst was addressed and several new PE-poly(alkene) glycol copolymers were prepared [68]. Commercially available oxidized polyethylene (CO2H terminated, both high and low molecular weight) was converted to the acid chloride and reacted with Jeffamine D or Jeffamine EDR, and subsequently converted to the tributylammonium bromide salt with butyl bromide. These new quaternary salts were shown to catalyze the nucleophihc substitution of 1,6-dibromohexane with sodium cyanide or sodium iodide. While none of the polymeric quaternary salts catalyzed the reaction as well as tetrabutylammonium bromide, the temperature-dependent solubility of the polymers allowed removal of the polymer by simple filtration. 

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