Acetic acid anhydride, reaction with radical

Pure ether is neutral in reaction, but, on exposure to air or O, especially in the light, it becomes acid from the formation of a. small quantity of acetic acid. HjSO< mixes with ether, with elevation of temperature, and formation of sulfovinic acid. Sulfuric anhydrid forms ethyl sulfate. HNOa, aided by heat, oxidizes ether to carbon dioxid and acetic and oxalic acids. Ether, saturated xvith HCl and distilled, yields ethyl chlorid. Cl, in the presence of H O, oxidizes ether, with formation of aldehyde, acetic acid, and chloral. In the absence of HaO, however, a series oF products of substitution are produced, in which 2, 4 and 10 atoms of H are replaced by a corresponding number of atoms of Cl. These substances in turn, by substitution of alcoholic radicals, or-... 

In the copolymerization experiments of MMA and AN with sodium acetate in a mixture of acetic acid and acetic anhydride, a platinum anode and mercury cathode, the reaction at the cathode proceeds by a free-radical mechanism where anionic ends may be terminated by acetic acid (36). 

Depending on the conditions, metal-catalyzed autoxidation of acetaldehyde can be utilized for the manufacture of either acetic acid or peracetic acid.321 In addition, autoxidation of acetaldehyde in the presence of both copper and cobalt acetates as catalysts produpes acetic anhydride in high yield.322 b The key step in anhydride formation is the electron transfer oxidation of acetyl radicals by Cu(II), which competes with reaction of these radicals with oxygen ... 

The reaction is used commercially in the oxidation of acetaldehyde to peracetic acid [234], acetic anhydride [235] and acetic acid [236], respectively (Fig. 4.79). In the production of acetic anhydride, copper(II) salt competes with dioxygen for the intermediate acyl radical affording acetic anhydride via the acyl cation. 

Neat A-(l -methyl-4-pentenyl)hydroxylamine underwent facile cyclization to the corresponding Y-hydroxypyrrolidine 1 on wanning briefly to 50- 60 °C, via a radical chain reaction involving the nitroxide radical. A-(l-Methyl-5-hexenyl)hydroxylamine cyclized to give A-hydroxypipe-ridine 2 only in refluxing xylene under high dilution conditions, this is necessary to avoid formation of byproducts. The cyclization was facilitated by the presence of a-methyl substituents in the hydroxylamine. Transannular cyclization of A-[(3-cyclohexenyl)methyl]hydroxylamine was not successful. Since the isolation of pure samples of the water-soluble and easily oxidized hydroxylamines was not a satisfactory procedure, the crude reaction mixtures were subjected to reduction with a zinc/acetic acid/acetic anhydride system to isolate acetylated cyclic amines. 

Manganese(III) can oxidize carbonyl compounds and nitroalkanes to carboxy-methyl and nitromethyl radicals [186]. With Mn(III) as mediator, a tandem reaction consisting of an intermolecular radical addition followed by an intramolecular electrophilic aromatic substitution can be accomplished [186, 187). Further Mn(III)-mediated anodic additions of 1,3-dicarbonyl and l-keto-3-nitroalkyl compounds to alkenes and alkynes are reported in [110, 111, 188). Sorbic acid precursors have been obtained in larger scale and high current efficiency by a Mn(III)-mediated oxidation of acetic acid acetic anhydride in the presence of butadiene [189]. Also the nitromethylation of benzene can be performed in 78% yield with Mn(III) as electrocatalyst [190]. A N03 radical, generated by oxidation of a nitrate anion, can induce the 1,4-addition of aldehydes to activated olefins. NOj abstracts a hydrogen from the aldehyde to form an acyl radical, which undergoes addition to the olefin to afford a 1,4-diketone in 34-58% yield [191]. 

Among such oxidations, note that liquid-phase oxidations of solid paraffins in the presence of heterogeneous and colloidal forms of manganese are accompanied by a substantial increase (compared with homogeneous catalysis) in acid yield [3]. The effectiveness of n-paraffin oxidations by Co(III) macrocomplexes is high, but the selectivity is low the ratio between fatty acids, esters, ketones and alcohols is 3 3 3 1. Liquid-phase oxidations of paraffins proceed in the presence of Cu(II) and Mn(II) complexes boimd with copolymers of vinyl ether, P-pinene and maleic anhydride (Amberlite IRS-50) [130]. Oxidations of both linear and cyclic olefins have been studied more intensively. Oxidations of linear olefins proceed by a free-radical mechanism the accumulation of epoxides, ROOH, RCHO, ketones and RCOOH in the course of the reaction testifies to the chain character of these reactions. The main requirement for these processes is selectivity non-catalytic oxidation of propylene (at 423 K) results in the formation of more than 20 products. Acrylic acid is obtained by oxidation of propylene (in water at 338 K) in the presence of catalyst by two steps at first to acrolein, then to the acid with a selectivity up to 91%. Oxidation of ethylene by oxygen at 383 K in acetic acid in... 

It was considered that cyclopentane systems might be formed from linoleate and related polyene acids either by the polar reaction sequence shown in Scheme 5 or its radical equivalent. When linoleate was reacted with acetic anhydride in a radical addition process promoted by ditertiarybutyl peroxide, 1 1 and 1 2 products were obtained. The former, after reaction with acidic methanol, were mainly unsaturated diesters such as [1], but some saturated compounds were also present and these may have been the cyclopentane derivatives ([2] and [3]) (9). 

It is well known that a variety of contaminants, such as sodium salts, water, and amines, can drastically decrease the stability of MA at elevated temperatures.In fact, tertiary amines and MA form explosive mixtures.Carbon dioxide is evolved when MA is treated with catalytic amounts of tertiary amines, giving a dark-colored polymeric material soluble in polar solvents.Homopolymerization of MA, with catalysts such as triethylamine and pyridine,occurs with decarboxylation and formation of dark-colored products, claimed to be an acrylic acid polymer, poly(maleic anhydride),or mixtures of the two materials. The polymerizations have been studied in tetrahydrofuran, chloroform, toluene, and pyridine at various temperatures. Reactions with catalytic amounts of pure pyridine proceeded very slowly, with formation of oligomeric and polymeric materials. Small amounts of water, maleic acid, acetic acid, and pyridinium salts aided the polymerization reaction. Radical inhibitors, such as sulfur, 2,2-diphenyl-1-picrylhydrazyl, and anthracene had no influence on reaction rates. 

Synthesis of Derivatives of Carboxylic Acids.—Dicarboxylic acid di-iodides are prepared (in 37 to 94% yield) from the corresponding diacid chlorides and sodium iodide. Carboxylic acid bromides are prepared under neutral conditions by the reaction of the corresponding acid with dibromotriphenylphosphorane. Radicals generated from cyclohexylmercuric acetate and NaBH4 react with maleic anhydride and related compounds to give cyclic derivatives of maleic acid in 55 to 98% yield. The chemistry of acyl cyanides has been reviewed. ... 

Blends of polychloroprene with PMMA do not show the chlorine radical migration effects observed in PVC/PMMA blends, nor the stabilization of the dehydrochlorination reaction, both of which are consistent with the nonradical mechanism proposed for HCl production in the former polymer, but there is a major effect of HQ in producing PMMA stabilization. Blends of PVC with PMMA also show the effect of HCl, but this is masked by the earlier destabilization due to Q radicals. Acetic acid from PVA also leads to anhydride rings in PMMA with similar effects. Blends of PVC with PVAC show mutual catalysis of the decomposition of each polymer by the primary decomposition product of the other. This is seen both in TVA studies similar to those illustrated for the PVC/PMMA system and from direct measurements of acid production, as illustrated in Figure 18, which show clearly the destabilization of each polymer. 

The lifetime of methyl oxirane with respect to reaction with OH will be about 25 days, assuming that the lower rate coefficients noted above are correct. No studies of the mechanism of the oxidation have been conducted. By analogy to chemistry of oxirane presented in section III-E-1.4, OH attack at the CH group (likely the dominant site) will result in the formation of acetic acid and CO, via a-ester rearrangement of the CH3C(0)0CH20 radical, and formic acetic anhydride [CH3C(0)0C(0)H] via reaction of this radical with O2. 

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