Benzylidene chloride

Benzal chloride (benzylidene chloride). Use 100 g. of toluene and continue the passage of chlorine imtil the increase in weight of the flask and contents is 74 g. or, alternatively, until the temperature rises to 187°, Collect the benzal chloride at 204 208° or at 104 105°/30 mm. Pure benzylidene chloride has b.p. 206°,... 

Benzal chloride [(dichloromethyl)benzene, a,a-dichlorotoluene, benzylidene chloride], C H CHCl, is a colorless Hquid with a pungent, aromatic odor. Benzal chloride is insoluble in water at room temperature but is miscible with most organic solvents. 

Chloro-benzal, n. benzal chloride, benzylidene chloride. -benzil, n. dichlorobenzil,... 

Benzylidene chloride, C6H5.CHC12, a colourless liquid which, like benzyl chloride, provokes tears, is the technical starting material for the preparation of benzaldehyde. Cf. Chap. V. 3, p. 209. 

The crude benzylidene chloride so obtained is boiled for four hours in a round-bottomed flask under an efficient reflux condenser with 500 c.c. of water and 150 g. of precipitated calcium carbonate... 

Chloroform and toluene yield by this process dimethyl-9 10-ditolyl-9 10-dihydroanthracene using aluminium chloride, tetratolylethane is obtained (B., 14, 1530). Benzylidene chloride and toluene yield dimethyl-9 10-diphenyl-9 10-dihydroanthracene. 

Reaction XCVHL Simultaneous Oxidation and Hydrolysis of Benzyl and Benzylidene Chlorides and their Derivatives. (Bl., 7,100 B., 10,1275).— If benzyl or benzylidene chloride, or derivatives, are refluxed with an aqueous solution containing sodium carbonate and potassium permanganate, simultaneous hydrolysis and oxidation occurs, and benzoic acid or one of its derivatives is produced. 

In the absence of catalysts, treatment of toluene with chlorine (or bromine) at the boiling point, preferably with exposure to sunlight or other bright light source, results in halogenation in the side chain. The introduction of the first chlorine atom, for example, proceeds at a much faster rate than the introduction of the second chlorine atom so that in practice the major portion of the toluene is converted into benzyl chloride (1) before appreciable chlorination of benzyl chloride occurs to give benzylidene chloride (2) and benzotrichloride (3). 

Rapid side-chain chlorination of toluene proceeds in the dark with sulphuryl chloride in the presence of benzoyl peroxide (0.001-0.005 mol per mol of S02C12) as catalyst (Expt 6.27). With an excess of sulphuryl chloride, benzylidene chloride is formed, but in this case chlorination does not proceed beyond this stage. 

Flash vacuum pyrolysis (FVP) of o-substituted benzylidene and benzyl chlorides154 was found to be a convenient method for the preparation of 1-chlorobenzocyclobutene, anthracene or benzofuran. In the case of o-methylbenzylidene chloride at 700 °C, 89% 1-chlorobenzocyclobutene were formed. Several benzylidene chlorides having different o-substituents were also pyrolyzed. Either o-benzylbenzylidene or o-benzylbenzyl chlorides gave anthracene in good yield. These processes were believed to proceed as shown in equation 70. 

Another reaction which can be brought about by PCI5 is the conversion of aldehydes and ketones into the corresponding geminal dichlorides and this is illustrated in Protocol 7 by the conversion of terephthalaldehyde 36 into the tetrachloride 37. Unusually for a reaction using PCI5, no HC1 is evolved here and the product is sufficiently unreactive to be isolated using an aqueous work-up. It should be noted that chlorination of aromatic aldehydes in this way is the method of choice for synthesis of benzylidene chlorides since the products obtained from the alternative chlorination of toluenes are always contaminated by the benzyl chlorides and benzotrichlorides. 

SYNS BENZYL DICHLORIDE BENZYLENE CHLORIDE BENZYLIDENE CHLORIDE BENZYLIDENE CHLORIDE pOT) CHLOROBENZAL CHLORURE de BENZYLIDENE piCHLORO-METHYL)BENZENE a-a-DICHLOROTOLUENE RCRA WASTE NUMBER U017 TOLUENE, a-a-DICHLORO-... 

The replacement of t-butyl chloride by compounds containing several chlorine atoms at the reaction centre hardly alters JC and AS for solvolysis in water (Table 6). Both parameters are, however, decreased substantially in solvents containing alcohol or acetone where a similar effect is also observed on the a-chlorination of benzylidene chloride and 3-phenylallyl chloride (Table 4). The presence of two or more halogen atoms at the reaction centre facilitates S l reaction by substantial contributions from structures such as (4) to the transition state this... 

Comparison of reactions of halocarbenes, which were produced from either alkylhalodiazirines by nitrogen extrusion, or by the usual method of eliminating hydrogen halide from dihaloalkanes by means of strong bases, bears special interest. Thus phenylchlorocarbene 177 was produced both from benzylidene chloride by potassium-t-butoxide, and by photolysis of phenylchlorodiazirine. ° Competition experiments with mixtures of olefins showed rate differences, especially remarkable for the isobutene-tetramethylethylene pair. The rate proportion was 0.20 when the diazirine... 

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