Benzyl alcohol preparation

It is prepared by the direct chlorination of toluene in the presence of PClj. It is purified by fractionation from the unchanged toluene and the higher chlorinated products. It is used for benzylating amines and for preparing benzyl alcohol. 

A crystalline derivative of benzyl alcohol cannot be obtained by using benzoyl chloride, because the benzyl benzoate, C HiCOOCHiCaHj, so obtained has m.p. 18°, and is thus usually liquid the present preparation illustrates therefore the use of a substituted benzoyl chloride (p-nitrobenzoyl chloride, m.p. 75°) in order to obtain a crystalline derivative of suitably high m.p. 

Benzyl alcohol. This alcohol, b.p. 205-5°, may be similarly prepared from benzaldehyde in approximately the same yield (compare Section IV, 123.)... 

Section 1115 The simplest alkenylbenzene is styrene (C6H5CH=CH2) An aryl group stabilizes a double bond to which it is attached Alkenylbenzenes are usu ally prepared by dehydration of benzylic alcohols or dehydrohalogena tion of benzylic halides... 

Benzyl saUcylate can be prepared by the reaction of ben2yl chloride with an alkaU salt of saUcyhc acid at 130—140°C or by the transesterification of methyl saUcylate with benzyl alcohol. It is used as a fixative and solvent for nitro musks and as a fragrance for detergents. Benzyl saUcylate was priced at... 

Ben /ben ate [120-51-4] CgH COOCH2CgH, mp, 21°C, cff , 1.118 bp, 323—324°C at 101.3 kPa , 1.5681. This is a colorless, oily liquid with a faiat, pleasant aromatic odor and a sharp, burning taste. It occurs naturally iu Pern and Tolu balsams, is spariugly volatile with steam, and is iusoluble iu water. Benzyl benzoate is prepared commercially by the direct esterification of benzoic acid and benzyl alcohol or by reaction of benzyl chloride and sodium benzoate. The pleasant odor of benzyl benzoate, like other benzoic esters, has long been utilized iu the perfume iadustry, where it is employed as a solvent for synthetic musks and as a fixative. It has also been used iu confectionery and chewing gum flavors. 

The NF and reagent grades are employed in the pharmaceutical industry which makes use of benzyl alcohol s local anesthetic, antiseptic, and solvent properties (17—20). It also finds use in cough symps and drops ophthalmic solutions bum, dental (21), and insect repeUant solutions and ointments and dermatological aerosol sprays. It is used in nail lacquers and as a color developer in hair dyes by the cosmetics industry (22), and in acne treatment preparations (23). 

Benzyl esters are readily prepared by many of the classical methods (see introduction to this chapter), as well as by many newer methods, since benzyl alcohol is unhindered and relatively stable to acid. 

Dimethoxybenzyl esters prepared from the acid chloride and the benzyl alcohol are readily cleaved oxidatively by DDQ (CH2CI2, H2O, rt, 18 h, 90-95% yield). A 4-methoxybenzyl ester was found not to be cleaved by DDQ. The authors have also explored the oxidative cleavage (ceric ammonium nitrate, CH3CN, H2O, 0°, 4 h, 65-97% yield) of a variety of 4-hydroxy- and 4-amino-substituted phenolic esters. ... 

The piperonyl ester can be prepared from an amino acid ester and the benzyl alcohol (imidazole/dioxane, 25°, 12 h, 85% yield) or from an amino acid and the benzyl chloride (Et3N, DMF, 25°, 57-95% yield). It is cleaved, more readily than a p-methoxybenzyl ester, by acidic hydrolysis (CF3COOH, 25°, 5 min, 91% yield). ... 

Acid-catalyzed dehydration (Section 5.9) This is a frequently used procedure for the preparation of alkenes. The order of alcohol reactivity parallels the order of carbocation stability R3C" > R2CH " > RCH2 ". Benzylic alcohols react readily. Rearrangements are sometimes observed. 

Other cases of O-to-C migration have been observed.This type of migration has been used to advantage in the preparation of 2-silylated benzyl alcohols. 

The piperonyl ester can be prepared from an amino acid ester and the benzyl alcohol (imidazole/dioxane, 25°, 12 h, 85% yield) or from an amino acid and the... 

In 1899 Thoms isolated an alcohol from Peru balsam oil, which he termed peruviol. This body was stated to have powerful antiseptic properties, but has not been further investigated until Schimmel Co. took up the subject. The oil after saponification was fractionated, and after benzyl alcohol had distilled over, a light oil with characteristic balsamic odour passed over. It boiled at 125° to 127° at 4 mm., and had a specific gravity 0 8987, optical rotation -1- 12° 22, and refractive index 1-48982. This body appeared to be identical with Hesse s nerolidol, whilst in physical and chemical properties it closely resembles peruviol. The characters of the various preparations were as follows —... 

Phenyl-ethyl alcohol, CgH. CHj. CHjOH, is the next highest homologue of the benzyl alcohol series. It is found naturally in rose -and neroli oils but as it is very soluble in water, it practically disappears from the distilled otto of rose and is dissolved in the rose water. Hence otto of rose with its beautiful perfume does not truly represent the odour of the rose. By the use of various isolated and synthetic bodies an artificial otto can be prepared which more closely resembles the rose odour than does the natural otto itself. But it is doubtful whether any really good artificial otto of rose can be prepared without some natural otto as its basis. 

Benzyl Ginnamate.—The cinnamic acid ester of benzyl alcohol is a natural constituent of storax, tolu, and Peru balsams. It is a crystalline Bubstance with a characteristic sweet balsamic odour. It may be prepared by heating sodium cinnamate, alcohol, and benzyl chloride together under a reflux condenser. It is a useful ester where a sweet balsamic odour is required to be introduced into a perfume, especially cf the heavy type. It forms white, glistening prisms, which melt at 39°, and.decompose when heated to 350°. The best commercial specimens have the following characters —... 

The required monobenzyl phenylmalonate, MP 68°C, was prepared by treating a mixture of phenylmalonlc acid (18 g) and benzyl alcohol (13 g) in carbon tetrachloride (80 ml) with dry hydrogen chloride. 

Fleischer1 prepared benzylaniline by heating aniline with benzyl chloride at i6o°. This reaction may be very violent and always leads to mixtures. Bernthsen and Trompetter 2 reduced thiobenzanilide with zinc and hydrochloric acid or sodium amalgam, while O. Fischer 3 reduced bcnzalaniline with sodium and alcohol, to benzylaniline. Knoevenagel4 obtained a 32 per cent yield of benzylaniline from benzyl alcohol and aniline in the presence of iodine. Ullmann5 describes the preparation of benzylaniline from benzyl chloride and excess of aniline at low temperatures. 

Acid chloride 5, prepared in two straightforward steps from the known benzylic alcohol 64e (see Scheme 6). reacts smoothly with naphthol 4 to give ester 3 in 91 % yield (see Scheme 3). With an... 

An important example is the preparation of carbobenzoxy chloride (PhCH20C0Cl) from phosgene and benzyl alcohol. This compound is widely used for protection of amino groups during peptide synthesis (see 10-55). 

Finally, reaction of primary, secondary, or tertiary alcohols 11 with Me3SiCl 14 in the presence of equivalent amounts of DMSO leads via 789 and 790 to the chloro compounds 791 [13]. n-Pentanol, benzyl alcohol, yS-phenylefhanol or tert-butanol are readily converted, after 10 min reaction time, into their chloro compounds, in 89-95% yield, yet cyclohexanol affords after reflux for 4 h cyclohexyl chloride 784 in only 6% yield [13] (Scheme 6.5). 1,4-Butanediol is cyclized to tetrahydrofuran (THF) [13a], whereas other primary alcohols are converted in 90-95% yield into formaldehyde acetals on heating with TCS 14 and DMSO in benzene [13b] (cf also the preparation of formaldehyde di(n-butyl)acetal 1280 in Section 8.2.1). 

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