Benzyl alcohol, from decomposition

Other hydrides used for the conversion of esters to alcohols are magnesium aluminum hydride in tetrahydrofuran [89, 577] and magnesium bromohydride prepared by decomposition of ethylmagnesium bromide at 235° for 2.5 hours at 0.5mm [7055]. They do not offer special advantages (the latter giving only 35% yield of benzyl alcohols from ethyl benzoate). 

Riboflavin forms fine yellow to orange-yeUow needles with a bitter taste from 2 N acetic acid, alcohol, water, or pyridine. It melts with decomposition at 278—279°C (darkens at ca 240°C). The solubihty of riboflavin in water is 10—13 mg/100 mL at 25—27.5°C, and in absolute ethanol 4.5 mg/100 mL at 27.5°C it is slightly soluble in amyl alcohol, cyclohexanol, benzyl alcohol, amyl acetate, and phenol, but insoluble in ether, chloroform, acetone, and benzene. It is very soluble in dilute alkah, but these solutions are unstable. Various polymorphic crystalline forms of riboflavin exhibit variations in physical properties. In aqueous nicotinamide solution at pH 5, solubihty increases from 0.1 to 2.5% as the nicotinamide concentration increases from 5 to 50% (9). 

Benzyioxycarbonyi chioride (Cbz-Ci, benzyi cbioroformate) [501-53-1] M 170.6, b 103 /20mm, d 1.195, n 1.5190. Commercial material is better than 95% pure and may contain some toluene, benzyl alcohol, benzyl chloride and HCl. After long storage (e.g. two years at 4 , Greenstein and Winitz [The Chemistry of the Amino Acids Voi 2 p. 890, J Wiley and Sons NY, 1961] recommended that the liquid should be flushed with a stream of dry air, filtered and stored over sodium sulfate to remove CO2 and HCl which are formed by decomposition. It may further be distilled from an oil bath at a temperature below 85 because Thiel and Dent [Annalen 301 257 1898] stated that benzyioxycarbonyi chloride decarboxylates to benzyl chloride slowly at 100 and vigorously at 155 . Redistillation at higher vac below 85 yields material which shows no other peaks than those of benzyioxycarbonyi chloride by NMR spectroscopy. LACHRYMATORY and TOXIC. 

In studies on l-diazo-2-ketosulfones, Shioiri et at. found that the thermal decomposition of benzoyl(sulfonyl)diazomethanes 6 with benzyl alcohol in acetonitrile also gave two products.<82CPB526> One is the 4-sulfonyloxazole 7 whereas the other product 8 results from rearrangement and reaction with the alcohol. The ratio of products varies with the nature of the sulfone substituent with the benzyl group giving highest yields of oxazole (Scheme 5). 

The ester is made by adding benzyl alcohol slowly to a preformed solution of phosgene in toluene at 12-16°C, toluene solvent finally being distilled off under vacuum. When discoloured phosgene was used (probably containing iron salts from corrosion of the cylinder), a violent explosion occurred during the distillation phase, presumably involving iron-catalysed decomposition of the chloroformate ester. 

The procedure given here is essentially that described previously by the submitters2 and is based on the early work of Knoevenagel.8 2-Phenylindazole has been prepared by reduction of N-(o-nitrobenzyl)aniline with tin and hydrochloric acid,4 by reduction of N-(o-nitrobenzyl) -N-nitrosoaniline with tin and hydrochloric acid,5 by dehydration of 2-(phenylazo)benzyl alcohol,6 by elimination of acetic acid from 2-(phenylazo)benzyl acetate,7 by dehydrogenation of 3,3a,4,5,6,7-hexahydro-2-phenyl-indazole with sulfur,8 and by thermal decomposition of o-azido-benzalaniline.9... 

MCBA enhances the solubility of the cobalt salts in MeCN solution, thereby ensuring better efficiency to a needed redox decomposition of the hydroperoxide intermediate of the substrate en route to the products". By using the HPI/Co(II)/MCBA/02 system in MeCN solution at 25 °C, competitive oxidations of p-X-substituted benzyl alcohols were run pairwise (Scheme 8). From the amount of the aldehydes produced, the relative reactivity (kx/ h) could be reckoned, and the acquired data provided a p = —0.68 in a Hammett plot vs. <7+. ... 

It is now generally admitted that this reaction involves both one-electron and two-electron transfer reactions. Carbonyl compounds are directly produced from the two-electron oxidation of alcohols by both Crvl- and Crv-oxo species, respectively transformed into CrIV and Crm species. Chromium(IV) species generate radicals by one-electron oxidation of alcohols and are responsible for the formation of cleavage by-products, e.g. benzyl alcohol and benzaldehyde from the oxidation of 1,2-diphenyl ethanol.294,295 The key step for carbonyl compound formation is the decomposition of the chromate ester resulting from the reaction of the alcohol with the Crvl-oxo reagent (equation 97).296... 

Ionic contributions to the transition state are also indicated from the effect of solvent polarity upon the rate of decomposition of l,2-di- -propyl-l-carbo-I-butylperoxycyclopropene. A linear correlation is observed with the yvalues of Dimroth and Reichardt for the following solvents ethyl benzene, chlorobenzene, benzonitrile, acetonitrile and benzyl alcohol . 

R = C6H4 in dimethyl formamide ° and with R = CgHjCHj in benzyl alcohol are 22 and 26,8 kcal.mole , respectively. These rather low values may be indicative of induced decomposition by radicals originating from the solvent or possibly an inversion reaction (c/., section 13.3.4). 

Studies of benzene and toluene oxidation in the turbulent flow reactor at Princeton University have provided valuable information on the mechanisms of oxidation at temperatures in excess of 1000 K [213]. The first extensive study of benzene and toluene at temperatures of about 750 K was made by Burgoyne [35]. Apart from CO and CO2, the major products of benzene oxidation that were detected were phenols and acids. An autocatalytic reaction was observed by Burgoyne [35] presumably driven by H2O2 formation and decomposition. Amongst the main products of toluene slow oxidation were benzyl alcohol, benzaldehyde and benzoic acid. Phenolic compounds were also reported. This reaction also showed an autocatalytic development. An equilibrium constant for the equilibrium between benzyl and benzylperoxy radicals has been measured by Fenter et al. [214], but this cannot be followed by an isomerization in the way that is possible in alkanes. 

Photochemical decomposition of pyrethrins and synthetic analogues can be slowed down by the simultaneous use of antioxidants and photoscreens. In the course of decomposition, chrysanthemic acid, phenylacetic acid, benzyl alcohol, benzaldehyde and benzoic acid are formed from resmethrin (32) as decomposition products and, at the same time, the furan ring undergoes an oxidative transformation (Ueda et al., 1974) ... 

A decline in catalytic activity with use was detected for reactions catalyzed by either species. Polymers 2 and 7 in the absence of cobalt both revealed excellent stability at 190 C (hydroformylation temperatures). This is illustrated by the TGA curves shown in Figure 4. Curve A shows an onset of decomposition for phosphinated polyphosphazene of 400 C, slightly better than that of phosphinated polystyrene (curve B, 20Z crosslinked curve C, 2Z crosslinked). Loss of phosphorus was observed over a period of 45 hours for a catalyst derived from 2 (2Z DVB crosslinked). The data depicted in Figure 5 reveal benzene, toluene, benzyl alcohol, diphenylphosphine and triphenyl phosphine as cleavage products. If one recalls the previously discussed homogeneous results it should be clear that the PPho is derived from a phosphide intermediate such as 8. ... 

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