Methacrylic acids, bromination

Ladenheim and Morawetz [23] also showed that the reactivity of the carboxylate units in partially ionized poly(methacrylic acid) (PMA) toward BrCH2COO in the bromine displacement reaction was greatly diminished, while the reaction proceeded at an appreciable rate with uncharged p-bromoacetamide [23]. This inhibition of the reaction of the polyanion with a small anionic reagent can be attributed to the electrostatic repulsion between the polymer and the reagent. 

Epoxy vinyl ester resins are a special class of unsaturated resin. This resin is made by capping an epoxy resin with methacrylic acid and then dissolving in styrene monomer to the desired viscosity. This gives mechanical properties similar to epoxy resins, but the processibility (low viscosity allowing for resin infusion processes) of an unsaturated polyester resin. As with unsaturated vinyl esters, the most common fire retardant vinyl ester resin is based on a resin made from a halogenated system, tetrabromobisphenol A. The level of bromine in the resin and the presence of antimony will determine the fire performance of the resin. These resins are normally used for corrosion resistant equipment or when fire performance and high mechanical properties are required. It is very difficult to get a low smoke value with a brominated vinyl ester resin again due to the fact that bromine... 

Of particular interest are the gas-solid bromination, chlorination and hydrobromina-tion of unsaturated acids complexed with cyclodextrins, which proceed with a high degree of chiral induction. For example, in the gas/solid chlorination of methacrylic acid complexed with a-cyclodextrin1032, (-)-2,3-dichloro-2-methylpropanoic acid is obtained in a 100% optical yield. 

In principle, the photoreactions of CT s are able to offer a great number of photoinitiator systems for radical polymerization. But, so far, this subject has only received little attention, and the current knowledge relative to the photochemistry of such complexes is poor. In addition to the amine complexes mentioned above, chinoline-bromine [124-127], chinoline-chlorine [128], 2-methylpyridine-chlorine [129], pyridine-bromine [130], IV-vinylpyrrolidone-bromine [131], acridone-bro-mine [132], acridone-chlorine [133], benzophenone-S02 [134], isoquinoline-S02 [135, 136], and 2-methylquinoline-S02 [136] combinations are used for radical polymerization of AN, alkyl methacrylates, acrylic and methacrylic acid, and for... 

Benzoyl Chloride Benzyl Alcohol Borax Boric Acid Bromine Butyl Acetate Butyl Methacrylate Butylamlne Calcium Chloride... 

As one of the enzymic reactions, asymmetric synthesis catalyzed by cyclodextrins has been studied in the past, but gave all the products in a low optical yield. We have already found a strong chiral induction for the chlorination of methacrylic acid in the crystalline cyclodextrin complexes. 100 % enantiomeric excess (e.e.) of (-)-2,3-dichloro-2-methyl-propionic acid and 88 % e.e. of its enantiomer were isolated in a- and 3-cyclodextrins, respectively. This paper describes asymmetric addition of gaseous halogens and hydrogen halides in the crystalline complexes comprising trans-cinnamic acid as a reactant and a- or 3-cyclodextrin as chiral matrix. Asymmetric bromination of menthyl cinnamate and of salts from the acid and several chiral amines have been reported, but gave low chiral inductions up to 2 16 % e.e.. 

Previously [8], the authors succeeded in achieving a strong chiral induction (88-100% ee) for the chlorination of methacrylic acid in the crystalline CD complexes. Here, we report on the asymmetric addition of gaseous bromine, chlorine, hydrogen bromide and hydrogen chloride to styrene in the crystalline complexes of a-CD (cyclohexa-amylose) or fi-CD (cyclohepta-amylose). 

Early investigations with poly(methacrylic acid) showed that this polymer can catalyze the nucleophilic displacement of bromine ion from a-bromo-acetamide. 

Photolysis of this polymer gives radicals on which side chains can be formed, giving graft polymerization 122, 123, 153). Similarly the polymerization of styrene (152) or vinyl acetate (157) in the presence of bromotrichloromethane gives telomers carrying terminal bromine atoms and trichloromethyl groups. By ultraviolet irradiation (3500 A) in the presence of methyl methacrylate the carbon-bromine links are broken and block copolymers are formed. The telomerization of acrylonitrile and acrylic acid with bromoform is based on the same technique the end groups of both polyacrylonitrile and polyacrylic acid were photolyzed in the presence of acrylamide and afforded polyacrylamide blocks linked to polyacrylonitrile or polyacrylic acid blocks (164, 165). 

Table 6.10 Comparison of experimental (Xf1) and theoretical (Xf1) values of compositions of terpolymers (styrene (M,) + acrylonitrile (M2) + bromine-containing monomer (M3)) prepared in dimethylformamide at low conversions (p < 0.1) and at various monomer feed compositions (xf) [312, 313]. 2,4,6-Tribromine phenyl ether of acrylic (I) [312] and methacrylic (II) [313] acids were used as M3...

The procedure for the elimination of HBr from the dibromo ester is a modification of the method of Lawton and co-workers for sui generis generation of the methyl or ethyl ester during a reaction. Methyl a-(bromomethyl)acrylate has also been prepared by bromination of methyl methacrylate in 700°C steam and by dehydrohalogenation with sodium acetate in acetic acid. Ethyl a-(bromomethyl)acrylate has been prepared by dehydrohalogenation with the monosodium salt of ethylene glycoP and ethyl diisopropylamine." The latter reaction was reported by Ohler et al. with no experimental details for the elimination reaction. The use of triethylamine as reported in this procedure appears to be the most efficient and convenient method for dehydrobromination to these acrylate esters. 

The next most important demand for methyl alcohol is as a raw material in the synthesis of many important organic compounds, including formaldehyde acetic acid chloro-methanes, compounds in which the hydroxyl group and/or one or more hydrogen has been replaced by fluorine, chlorine, bromine, and/or iodine methyl methacrylate, a compound from which acrylic plastics are made methylamines, the source of another important class of plastics, dimethyl terephthalate, the monomer for yet another class of plastics and other products. 

The bromine atoms of m- and p-bromobenzoic acids and o-bromobenzoates can be displaced by acrylate, crotonate, and methacrylate esters in the presence of palladium. The reaction seems applicable to the synthesis of a wide variety of... 

Isobutylene/isoprene copolymer, brominated 2-lsocyanatoethyl methacrylate Isopropanolamine Lactic acid Lead oxide, yellow... 

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