Toluene benzyl chloride

Chlorinated paraffins. Chlorinated ben2enes. Ring-chlorinated toluenes. Benzyl chloride. 

Mikhailova TV Comparative toxicity of chloride derivatives of toluene—benzyl chloride, benzal chloride and benzotrichloride. Fed Proc 24 T877-800, 1965... 

Side-Chain Chlorination of Toluene. Benzyl chloride, used mainly in the manufacture of plasticizers, may be prepared by the thermal or photochemical chlorination of toluene.191,192 In the thermal process chlorine is passed through toluene at 65-100°C. To minimize the formation of benzal chloride and benzotrichloride, the conversion is limited to about 50%. Since the density of the reaction mixture increases linearly with the formation of benzyl chloride,145 measurement of density is used to monitor the progress of the reaction. The overall yield based on toluene is about 90%, and the maximum conversion to benzyl chloride is above 70%. Higher yields in photochemical chlorination may be achieved. 

The impurities present after chlorination are unchanged toluene, benzyl chloride and benzotrichloride. 

T.V. Mikhailova, Comparative toxicity of chloride derivatives of toluene benzyl chloride, benzal chloride, and benzotrichloride. Gig. Tr. Prof. Zabol. 8 14, 1965. 

Toluene Benzyl chloride Benzal chloride Benzotrichloride... 

This reaction was initially studied by von Baeyer in 1872. It is an acid-catalyzed condensation of aromatic compounds with formaldehyde or formaldehyde derivatives. In normal conditions, the reactive benzene derivatives such as phenols and arylamines are applied to condense with formaldehyde however, a small number of less-reactive aromatics have also been used in this reaction, including benzene, toluene, benzyl chloride,biphenyl, iodobenzene, naphthalene, and mesitylene. Although no yields were given in the early studies, it is reasonable to obtain 70-80% yield for this type of reaction. Many other reactions have been developed to synthesize diarylmethanes, including Katritzky s benzotriazole method, Kochi s dealkylative coupling," Fukuzaw s 1,3-propandiol method, and the reduction method. In general, the condensation occurs at the /tflra-position of substituted aromatics. 

Versatile aromatic intermediates, especially in the manufacture of plant protection agents and dyestuffs, are the chlorinated toluene derivatives o- and p-chloro-toluene, benzyl chloride, and benzotrichloride, together with toluene nitro-deriva-tives. Sulfonic acids of toluene have extensive applications as surfactants. 

In the following preparation, the oxidation of benzyl chloride instead of toluene is therefore given in order to reduce the time required. It should be borne in mind, however, that the procedure is othenvise independent of the nature of the side chain. 

In the absence of catalysts, toluene when treated with chlorine (or bromine) at the boiling point, preferably with exposure to sunlight or other bright light source, undergoes halogenation in the side chain. The entrance of the first chlorine atom, for example, proceeds at a much faster rate than the entrance of the second chlorine atom so that in practice the major portion of the toluene is converted into benzyl chloride before appreciable chlorination of benzyl chloride occurs ... 

Method 2. In a 500-ml. rovmd-bottomed flask, fitted with an efficient reflux condenser, place 92 g, (106 ml.) of toluene, 68 g. (41 ml.) of redistilled sulphuryl cldoride and 1 g, of dibenzoyl peroxide (Section IV,196). Reflux gently, when a vigorous reaction takes place the reaction is complete in 30 minutes. Isolate the benzyl chloride as described in Method 1. The yield is 50 g. 

Ingold and his co-workers used the competitive method in their experiments, in which nitration was brought about in acetic anhydride. Typically, the reaction solutions in these experiments contained o-8-I 4 mol of nitric acid, and the reaction time, depending on the reactivities of the compounds and the temperature, was 0-5-10 h. Results were obtained for the reactivities of toluene, > ethyl benzoate, the halogenobenzenes, ethyl phenyl acetate and benzyl chloride. Some of these and some later results are summarized in table 5.2. Results for the halogenobenzenes and nitrobiphenyls are discussed later ( 9.1.4, lo.i), and those for a series of benzylic compounds in 5,3.4. 

The selective monochlorination of the methyl group in toluene to give benzyl chloride with SO2CI2 is possible with catalysis by Pd(Ph3P)4[124],... 

Benzyl Chloride. Benzyl chloride is manufactured by high temperature free-radical chlorination of toluene. The yield of benzyl chloride is maximized by use of excess toluene in the feed. More than half of the benzyl chloride produced is converted by butyl benzyl phthalate by reaction with monosodium butyl phthalate. The remainder is hydrolyzed to benzyl alcohol, which is converted to ahphatic esters for use in soaps, perfume, and davors. Benzyl salicylate is used as a sunscreen in lotions and creams. By-product benzal chloride can be converted to benzaldehyde, which is also produced directiy by oxidation of toluene and as a by-product during formation of benzoic acid. By-product ben zotrichl oride is not hydrolyzed to make benzoic acid but is allowed to react with benzoic acid to yield benzoyl chloride. 

In the past benzal and benzyl chlorides were co-produced for the manufacture of benzaldehyde and benzyl alcohol, but today the vast majority of the benzaldehyde produced from benzal chloride is that which is made from recovered (by-product) material. For an historical article regarding the chlorination of toluene and the subsequent production of benzaldehyde, benzyl alcohol, and benzoic acid, see reference 4. 

Manufacture. Today benzyl alcohol is almost universally manufactured from toluene which is first chlorinated to give benzyl chloride [100-44-7]. This is then hydrolyzed to benzyl alcohol by treatment with aqueous sodium carbonate. 

Continuous chlorination of benzene at 30—50°C in the presence of a Lewis acid typically yields 85% monochlorobenzene. Temperatures in the range of 150—190°C favor production of the dichlorobenzene products. The para isomer is produced in a ratio of 2—3 to 1 of the ortho isomer. Other methods of aromatic ring chlorination include use of a mixture of hydrogen chloride and air in the presence of a copper—salt catalyst, or sulfuryl chloride in the presence of aluminum chloride at ambient temperatures. Free-radical chlorination of toluene successively yields benzyl chloride, benzal chloride, and benzotrichloride. Related chlorination agents include sulfuryl chloride, tert-huty hypochlorite, and /V-ch1orosuccinimide which yield benzyl chloride under the influence of light, heat, or radical initiators. 

Benzyl chloride is manufactured by the thermal or photochemical chlorination of toluene at 65—100°C (37). At lower temperatures the amount of ring-chlorinated by-products is increased. The chlorination is usually carried to no more than about 50% toluene conversion in order to minimize the amount of benzal chloride formed. Overall yield based on toluene is more than 90%. Various materials, including phosphoms pentachloride, have been reported to catalyze the side-chain chlorination. These compounds and others such as amides also reduce ring chlorination by complexing metallic impurities (38). 

Under typical Hquid-phase chlorination conditions the maximum conversion to benzyl chloride of about 70% is reached after reaction of about 1.1 moles of chlorine per mole of toluene (39). Higher yields of benzyl chloride have been claimed 80% for low temperature chlorination (40) 80—85% for light-catalyzed chlorination in the vapor phase (41) and 93.6% for continuous chlorination above 125°C in a column packed with glass rings (42). 

Benzotrichloride is produced from total side-chain chlorination of toluene or of residual products from benzyl chloride production. In Western Europe, Bayer has the largest capacity (14,000 t/yr), and there are only two significant producers in the United States Occidental Chemical in Niagara EaUs, New York (20,000 t/yr), and Velsicol Chemical (11,000 t/yr). Total capacity in the western world is 68,000 t/yr and production of benzotrichloride in 1988 was estimated at 31,500 t. 

Ring-Substituted Derivatives The ring-chlorinated derivatives of benzyl chloride, benzal chloride, and benzotrichloride are produced by the direct side-chain chlorination of the corresponding chlorinated toluenes or by one of several indirect routes if the required chlorotoluene is not readily available. Physical constants of the main ring-chlorinated derivatives of benzyl chloride, benzal chloride, and benzotrichloride are given in Table 4. 

Benzyl chloride Toluene, a-chloro- (8) Benzene, (chloromethyl)- (9) (lQQ-44-7). 

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. 

Rates that are independent of aromatic substrate concentration have been found for reaction of benzyl chloride catalyzed by TiCl4 or SbFj in nitromethane. This can be interpreted as resulting from rate-determining formation of the electrophile, presumably a benzyl cation. The reaction of benzyl chloride and toluene shows a second-order dependence on titanium tetrachloride concentration under conditions where there is a large excess of hydrocarbon. ... 

NOTE - Petrochemical plants also generate significant amounts of solid wastes and sludges, some of which may be considered hazardous because of the presence of toxic organics and heavy metals. Spent caustic and other hazardous wastes may be generated in significant quantities examples are distillation residues associated with units handling acetaldehyde, acetonitrile, benzyl chloride, carbon tetrachloride, cumene, phthallic anhydride, nitrobenzene, methyl ethyl pyridine, toluene diisocyanate, trichloroethane, trichloroethylene, perchloro-ethylene, aniline, chlorobenzenes, dimethyl hydrazine, ethylene dibromide, toluenediamine, epichlorohydrin, ethyl chloride, ethylene dichloride, and vinyl chloride. 

This acid, CgHj. CH COOH, is a sweet-smelling substance, especially recommended for sweetening soap perfumes. It occurs in neroli oil, and has a sweet honey-like odour. It is formed by converting toluene into benzyl chloride which is converted into benzyl cyanide, which is digested with dilute sulphuric acid, and so converted into phenyl-acetic acid. It is a crystalline body, melting at 76° to 76 5° and Iwiling at 266°. It has been isolated from oil of neroli. 

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