Reaction benzyl acetate production

Nearly all uses and appHcations of benzyl chloride are related to reactions of the active haUde substituent. More than two-thirds of benzyl chloride produced is used in the manufacture of benzyl butyl-phthalate, a plasticizer used extensively in vinyl flooring and other flexible poly(vinyl chloride) uses such as food packaging. Other significant uses are the manufacture of benzyl alcohol [100-51-6] and of benzyl chloride-derived quaternary ammonium compounds, each of which consumes more than 10% of the benzyl chloride produced. Smaller volume uses include the manufacture of benzyl cyanide [140-29-4], benzyl esters such as benzyl acetate [140-11-4], butyrate, cinnamate, and saUcylate, benzylamine [100-46-9], and benzyl dimethyl amine [103-83-8], and -benzylphenol [101-53-1]. In the dye industry benzyl chloride is used as an intermediate in the manufacture of triphenylmethane dyes (qv). First generation derivatives of benzyl chloride are processed further to pharmaceutical, perfume, and flavor products. 

Direct esr evidence for the intermediacy of radical-cations was obtained on flowing solutions of Co(III) acetate and a variety of substituted benzenes and polynuclear aromatics together in glacial acetic acid or trifluoroacetic acid solution . A p value of —2.4 was reported for a series of toluenes but addition of chloride ions, which greatly accelerated the reaction rate, resulted in p falling to —1.35. Only trace quantities of -CH2OAC adducts were obtained and benzyl acetate is the chief product from toluene, in conformity with the equation given above. 

Table 5.3 Initial reaction mixture for the production of benzyl acetate.

BASF has developed a direct electrochemical process based on anodic acetoxylation for the production of aromatic aldehydes on industrial scale [40,146,147]. The reaction passes smoothly through the benzyl acetate stage. 

Oxidation with peroxydisulfate in AcOH in the presence of catalytic amounts of iron and copper salts gives benzylic acetates in good yields.785,861 The reaction of lead tetraacetate with alkylarenes in AcOH provides benzylacetates in moderate yields.693 Most of these oxidations usually involve methyl-substituted benzenes since aromatics with longer chain produce different side products. 

Purification. Small amounts of reaction by-products are produced during the liquid-phase oxidation of toluene. These by-products include acetic and formic acids, benzene, benzaldehyde, benzyl alcohol, aliphatic benzyl esters such as benzyl formate and benzyl acetate, biphenyl, 2-, 3-, and 4-methylbiphenyls, and phthalic acid. Of these only benzaldehyde and benzene [71 -43-2] are currendy separated commercially. 

Other acetyl chloride preparations include the reaction of acetic acid and chlorinated efhylenes in the presence of tenic chloride [7705-08-0] (29) a combination of benzyl chloride [100-44-7] and acetic acid at 85% yield (30) conversion of ediylidene dicliloride, in 91% yield (31) and decomposition of ethyl acetate [141-78-6] by the action of phosgene [75-44-5], producing also ethyl chloride [75-00-3] (32). The expense of raw material and capital cost of plant probably make tliis last route prohibitive. Chlorination of acetic acid to monocliloroacetic acid [79-11-8] also generates acetyl chloride as a by-product (33). Because acetyl cliloride is costly to recover, it is usually recycled to be converted into monocliloroacetic acid. A salvage method in which the mixture of HQ. and acetyl cliloride is scrubbed with H2S04 to form acetyl sulfate has been patented (33). 

The reaction of ceric acetate with aromatic hydrocarbons can be used for synthesis of arylacctic acids. Thus the reaction of ceric acetate with toluene in acetic anhydridc-acetic acid gives as the major products benzyl acetate and tolylacetic acid (29% yield). 

Trimethylsilyl chloride also gives the N -product alone in simple models, but this is probably the consequence of thermodynamic control in any event N -trialkylsilyl derivatives are much too labile to be useful as stepping stones to N"-alkylhistidines. The only thoroughly studied example of exclusive mono-N -derivatization is the reaction of acetic anhydride with acylhistidine esters, when thermodynamic control appears to operate. Thus, N -(benzyl-oxycarbonyl)histidine methyl ester gives only the M-acetyl derivative, providing a third kind of intermediate which is useful for N"-alkylation with reactive halides (see Section 2.6.2.3).1 1... 

Generally, anodic benzylic substitution reactions take place readily. However, anodic benzylic fluorination does not always occur. The major competitive reaction is acet-amidation when MeCN is used as a solvent [24-26]. In contrast to these cases, triphenylmethane is selectively monofluorinated in 80% yield [27]. When Et4NF-/7HF n = 3,4,5) is used in the absence of MeCN, anodic fluorination of toluene and mono-fluoromethylbenzene provides mainly mono- and difluoromethylbenzenes, respectively [22]. On the other hand, difluoromethylbenzene affords only products fluorinated in the benzene ring [Eq. (4)] [28]. 

Toluene was oxidized to a mixture of benzyl acetate (31) and benzylidene diacetate (32) on reaction with oxygen in the presence of a silica supported Pd-Sn catalyst.A reaction run in HOAc/KOAc at 70°C under an atmosphere of oxygen gave a near 3 1 ratio of the monoacetate to the diacetate at 98% conversion (Eqn. 21.40). The two products are formed in parallel reactions as the benzylacetate does not react further under these reaction conditions. Substituted diphenylmethanes were oxidized to the diphenyl ketones by refluxing them in air in a DMF solution containing a copper powder catalyst.""... 

Alkyl-substituted benzenes and alkyl-substituted aromatic compounds constitute the starting molecules. Benzaldehydes, benzyl acetates, and to some extent also benzyl alcohols are the main intermediates aromatic carboxylic acids are the desired products. The intermediate benzyl acetates, benzaldehydes, and the corresponding acids can also be formed in stoichiometric reactions with Co(OAc)3 in acetic acid in the absence of oxygen. 

The use of these boryl complexes in catalytic, enantioselective additions to aldehydes by silyl ketene acetals has also been the subject of intense investigation by Yamamoto (Eq. 30) [108]. Although ethyl and benzyl acetate-derived enol silanes furnished racemic products, the phenyl acetate-derived trimethylsilyl ketene acetals proved optimal, giving adducts in up to 84% ee. Additionally, Yamamoto has documented the use of 184 in aldol addition reactions of propionate- and isobutyrate-derived enol silanes (Eqs. 31 and 32). Thus, the addition of the phenyl acetate derived (E)-enol silane afforded adducts as diastereomeric mixtures with the syn stereoisomer displaying up to 97% ee (Eq. 32). 

Oxidations of methylaromatic compounds, without phenolic group, in the presence of palladium based catalysts are well documented (ref. 9). Toluene (ref. 9), o-, m-, p-xylene (refs. 9c-e), mesitylene (ref. 9c), hexamethylbenzene (ref. 9c), o-methylanisole (ref. 9e) and p-methylanisole (ref. 9d) are among the main substrates which have been studied. The solvent of choice for the reaction is acetic acid and the main product is the corresponding benzylic acetate. Aldehyde... 

Aldol reactions. The reaction of polymer-supported ketene O-silyl 5-benzyl acetals A ith aldehydes" and imines gives reasonable yields of the condensation products, which release 1,3-diols and amino alcohols, respectively, from the resin by treatment with LiBH. ... 

The function of solid-liquid phase transfer catalysis (SLPTC) is to conduct the reaction of a solid salt and the organic reactant using a PT catalyst that is easily dissolved in the organic phase in the absence of water. These catalysts can be tertiary amines, quaternary ammonium salts, diamines, crown ethers and cryptands, among which crown ethers, act as the catalysts because of their specific molecular structures [183-186]. Starks et al. [183] indicated that 100% of the yield of product benzyl acetate was obtained at 25°C in 2 h for... 

---