Benzyl acetate, reaction

Mix 31 g. (29-5 ml.) of benzyl alcohol (Section IV, 123 and Section IV,200) and 45 g. (43 ml.) of glacial acetic acid in a 500 ml. round-bottomed flask introduce 1 ml. of concentrated sulphuric acid and a few fragments of porous pot. Attach a reflux condenser to the flask and boil the mixture gently for 9 hours. Pour the reaction mixture into about 200 ml. of water contained in a separatory funnel, add 10 ml. of carbon tetrachloride (to eliminate emulsion formation owing to the slight difference in density of the ester and water, compare Methyl Benzoate, Section IV,176) and shake. Separate the lower layer (solution of benzyl acetate in carbon tetrachloride) and discard the upper aqueous layer. Return the lower layer to the funnel, and wash it successively with water, concentrated sodium bicarbonate solution (until effervescence ceases) and water. Dry over 5 g. of anhydrous magnesium sulphate, and distil under normal pressure (Fig. II, 13, 2) with the aid of an air bath (Fig. II, 5, 3). Collect the benzyl acetate a (colourless liquid) at 213-215°. The yield is 16 g. 

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. 

Example 5.4 Benzyl acetate is used in perfumes, soaps, cosmetics and household items where it produces a fruity, jasminelike aroma, and it is used to a minor extent as a flavor. It can be manufactured by the reaction between benzyl chloride and sodium acetate in a solution of xylene in the presence of triethylamine as catalyst9. 

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

Transfer hydrogenolysis of benzyl acetate was studied on Pd/C at room temperature using different formate salts.244 Hydrogen-donating abilities were found to depend on the counterion K+ > NH4 + > Na+ > Li+ > H+. Formate ion is the active species in this reaction. Adsorption of the formate ion on the Pd metal surface leads to dissociative chemisorption resulting in the formation of PdH- and C02. The kinetic isotope effect proves that the dissociative chemisorption of formate is the rate-limiting step. The adsorption and the surface reaction of benzyl acetate occurs very rapidly. 

Benzyl acetate was prepared by addition of benzyl chloride (containing 0.6% pyridine as stabiliser) to preformed sodium acetate at 70°, followed by heating at 115°, then finally up to 135°C to complete the reaction. On one occasion, gas began to be evolved at the end of the dehydration phase, and the reaction accelerated to a violent explosion, rupturing the 25 mm thick cast iron vessel. This was attributed to presence of insufficient pyridine to maintain basicity, dissolution of iron by the... 

Preparation of diethyl 3,5-di-t-butyl-4-hydroxybenzylphosphonate — Reaction of a benzylic acetate with a trialkyl phosphite... 

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. 

Glycosyl acetates. Reaction of l-0-acetyl-2,3,5-tri-0-benzyl-D-ribofuranose (99) with various enoxysilanes in the presence of TrC104 afforded 1,2-czj-C-glycosyl compounds with high stereoselectivity and yields higher than 90% (Scheme 34).106... 

In refluxing acetonitrile the activities of catalysts 57-60 were 60 > 59 > 58 > 57, while in refluxing dioxane 60 > 57 > 58 = 59. However, the reactions were very slow. In dioxane only the soluble 18-crown-6 ether (60) gave a yield of benzyl acetate of more than 31 % in 2 days. Details of catalyst and potasium acetate particle size and stirring method were not reported l82). The higher activity of the solid catalyst 57 than of the soluble analog 58 is highly unusual because mass transfer and intra-... 

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. 

Co2(CO)8-catalyzed reactions of benzylic acetates with trimethylsilane and CO proceed under mild reaction conditions to give trimethylsilylethers of /3-phenethylalcohol in 43-76% yield. The highest yields are observed for benzyl acetates with electron-donating substituents.111 Secondary alkyl acetates are also good substrates in the reaction system, yielding enol silyl ethers.112 In addition, the cobalt complex is an effective catalyst for siloxymethylation of five-membered cyclic ortho esters, as shown in Eq. (41).113... 

In the reaction of toluene to form bitolyls and benzyl acetate catalyzed by PdCl2 in the presence of NaOAc, the bitolyl/benzyl acetate ratio has been found to vary from 3.8 to 0.0074 as the sodium acetate/ PdCl2 ratio is varied from 50-20 (103). 

A similar Te02/HBr catalyst has been used in acetic acid for the oxidation of propene at ca. 120 °C to propene oxide and propene glycol via 1,2-diacetoxypropane.361,362 However, this reaction gives lower yields because of side allylic oxidation reactions. Oxidation of toluene under similar conditions (Te02/LiBr, 160 °C) results in the formation of methylbenzyl acetate mixtures rather than benzyl acetate as observed with Se02/LiBr catalyst (equation 133).363... 

Oxidation of alkylbenzene by Co(OAc)3 mainly occurs at the side-chain benzylic positions, without formation of nuclear adducts. In nitrogen, benzylic acetates predominate, whereas aromatic acids are favored when oxygen is present.512 Thus toluene is transformed into benzyl acetate and benzaldehyde by Co(OAc)3 in AcOH under anerobic conditions.553 When this reaction is... 

Chemical kinetics deductions are, in some circumstances, possible from a reaction system using a dispersed solid. If the solid is entirely insoluble, for example a supported catalyst, true surface kinetics can be obtained provided (i) it can be shown that the chemical reaction on the surface is much slower than the associated mass transfer, and (ii) the surface area of the solid can be obtained. These conditions applied in the case of the oxidation of an aqueous solution of hydrazine using a dispersion of insoluble barium chromate [16]. Another case is where it can be shown that an increase in the amount of the solid component does not increase the reaction rate. In this case, exemplified by the formation of benzyl acetate from benzyl bromide and solid sodium acetate in toluene solvent, it is likely that the reaction occurs in the solution phase and that the reaction is proceeding at the saturation concentration of the solid reactant in the liquid phase [17]. 

The total synthesis of (+)-Macbecin I 78 [39] began with aldehyde 73, prepared via the addition of optically pure crotylsilane onto a benzylic acetal, which underwent an SMS reaction to give ester 75 in a 12 1 syn/anti ratio. Oxidative cleavage of the double bond, Wittig olefination of the resulting aldehyde and a reduction-oxidation sequence yielded a,/ -unsaturated aldehyde 76. A second SMS reaction was then performed leading to polyether 77 (dr > 20 1) that contains all the chiral centers of (+)-Macbecin I 78, Scheme 13.31. 

Benzyl acetates react with trimethylsilane and CO in the presence of Co2(CO)8 as catalyst to give P-phenethyl alcohols by a one-carbon homologation. The active catalyst is assumed to be (CH3)3SiCo(CO)4. The reaction proceeds under CO at atmospheric pressure at 25°. It fails with benzyl alcohol itself, but is successful with benzyl formate and benzyl methyl ether.5... 

C(6) to give an oxonium ion. Nucleophilic attack, probably by acdtic acid, on the benzylic carbon gives a O-acetyl sugar derivative and benzyl acetate. Glycosides are also acetolysed under these reaction conditions. 

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