Esters alkali metals

Catalysis by metal ions has also been demonstrated in the hydrolysis of esters containing an a- or /I-carboxylate ion. The alkaline hydrolysis of potassium ethyl oxalate and potassium ethyl malonate is catalyzed by calcium, barium, hexaamino-cobalt(III), and thallous ion, in that order (22). The oxalate ester is catalyzed to a greater extent than the malonate ester, which in turn is more susceptible to catalysis by metal ion than the corresponding adipate ester. Alkali metal ions, on... 

Alcoholysis diacetate ester of polytetramefhylene ether + alkanol = polytetramethylene ether glycol (PTMEG) + alkanol acetate ester alkali metal oxide or alkaline earth metal oxide in the presence of hot methanol PTMEG is used to make polyesters, polyurethanes etc. complete conversion of diester. [86]... 

Residual monomers in the latex are avoided either by effectively reacting the monomers to polymer or by physical or chemical removal. The use of tert-huty peroxypivalate as a second initiator toward the end of the polymeri2ation or the use of mixed initiator systems of K2S20g and tert-huty peroxyben2oate (56) effectively increases final conversion and decreases residual monomer levels. Spray devolatili2ation of hot latex under reduced pressure has been claimed to be effective (56). Residual acrylonitrile also can be reduced by postreaction with a number of agents such as monoamines (57) and dialkylamines (58), ammonium—alkali metal sulfites (59), unsaturated fatty acids or their glycerides (60,61), their aldehydes, esters of olefinic alcohols, cyanuric acid (62,63), andmyrcene (64). 

The chemical resistance of PCTFE is good but not as good as that of PTFE. Under certain circumstances substances such as chlorosulphonic acid, molten caustic alkalis and molten alkali metal will adversely affect the material. Alcohols, acids, phenols and aliphatic hydrocarbons have little effect but certain aromatic hydrocarbons, esters, halogenated hydrocarbons and ethers may cause swelling at elevated temperatures. 

Alkali metal alkoxides, r-butyl acetate neat, 45°, 30 min, 98% yield of r-butyl ester from methyl benzoate. The rate constant for the reaction increases with increasing ionic radius of the metal and with decreasing polarity of the solvent. Equilibrium for the reaction is achieved in <10 sec. Other examples eire presented. " ... 

I) Refluxing said benzyl ester with an aqueous alcoholic alkali metal hydroxide solution to saponify the benzyl ester group, neutralizing the saponification mixture by the addition of hydrochloric acid, extracting the neutralized mixture with chloroform, and separating the resulting (S,N-ditrityl-L-cysteinyl)-L-proline. 

Scheme 2.34).319 322 Since the alkali metal salt formed does not react with ester groups, the molar mass is not limited by the reverse reaction and this polyesterification can be regarded as a nonequilibrium one. 

When a carbonyl group is bonded to a substituent group that can potentially depart as a Lewis base, addition of a nucleophile to the carbonyl carbon leads to elimination and the regeneration of a carbon-oxygen double bond. Esters undergo hydrolysis with alkali hydroxides to form alkali metal salts of carboxylic acids and alcohols. Amides undergo hydrolysis with mineral acids to form carboxylic acids and amine salts. Carbamates undergo alkaline hydrolysis to form amines, carbon dioxide, and alcohols. 

From both economic and ecological points of view, substances derived from esters of monocarboxylic acids sulfonated in the a position form an interesting class of surfactants [1]. The general formula of these a-sulfomonocarboxylic esters, also called a-sulfo fatty acid esters or, in short, a-ester sulfonates, is Rj-CH(S03Me)-C00-R2 (with Rj and R2 = alkyl groups, Me = alkali metal). 

When ethoxylated nonylphenol and polyethylene glycol is treated with a mixture of H2S04 and H3P04 and neutralized with an alkali metal hydroxide or amine, surfactants containing sulfate esters and phosphate esters are obtained which cause little corrosion of metals such as surfaces of laundering equipments and automobiles [55]. 

The yielded product can be converted to a surface-active compound if at least one ester group has been transformed to the free acid or an alkali metal salt thereof [160]. There are also many compounds from phosphinic acid derivatives claimed to be useful as sequestrants and builders to improve detergency, especially bisphosphonylmethylphosphinic acids and polyphosphinic acids [structures (9) and (10)], respectively ... 

Although the aminolysis of esters to amides is auseful synthetic operation, usually it presents some disadvantages in terms of drastic reaction conditions, long reaction times or strong alkali metal as catalyst, which are usually not compatible with other functional groups in the molecule [6]. For this reason, enzymatic aminolysis of carboxylic acid derivatives offers a clean and ecological way for the preparation of different kind of amines and amides in a regio-, chemo-, and enantioselective manner. 

Styrene Free radical polymerization similar to the above. Also susceptible to rapid cationic polymerization induced by AlCb at —80°C and to anionic polymerization using alkali metals or their hydrides —CH2—CH— (ieHs T = 100 Amorphous, even when stretched. Hard. Soluble in aromatic hydrocarbons, higher ketones, and esters... 

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. 

Alternatively, esterification of carboxylic acid can be carried out in aqueous media by reacting carboxylic acid salts with alkyl halides through nucleophilic substitutions (Eq. 9.10).20 The reaction rate of alkyl halides with alkali metal salts of carboxylic acids to give esters increases with the increasing concentration of catalyst, halide, and solvent polarity and is reduced by water. Various thymyl ethers and esters can be synthesized by the reactions of thymol with alkyl halides and acid chlorides, respectively, in aqueous medium under microwave irradiation (Eq. 9.11).21 Such an esterification reaction of poly(methacrylic acid) can be performed readily with alkyl halides using DBU in aqueous solutions, although the rate of the reaction decreases with increasing water content.22... 

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