Synthesis of 2-toluenesulfonyl chloride

Preparation of 2-toluenesulfonyl chloride

100 g of pure toluene are slowly run into 500 g of chlorosulfonic acid cooled to 0° C in a pot fitted with good mechanical agitation, the temperature during the addition being kept at 0-5° C. The reaction flask in which the sulfonation is carried out should have an exit tube for the escape of hydrogen chloride, which may be absorbed in fuming sulfuric acid with the formation of more chlorosulfonic acid. When all the toluene has been added stirring is continued for about 12 hours at the same temperature. The mass is then poured on to ice, when an oily layer separates. The liquid 2-toluenesulfonyl chloride, which usually contains some of the solid 4-toluenesulfonyl chloride, is then separated and, after further treatment with ice and salt, is filtered and the 2-toluenesulfonyl chloride separated from the salt solution in a funnel yield 85% or 110 g of 2-toluenesulfonyl chloride.

Systematic organic chemistry, by W. M. Cumming, 317-318, 1937.

130 g pure toluene are heated with 450 g concentrated sulfuric acid in a cast-iron pot fitted with a suitable agitator. A crystal of iodine is added, and the temperature allowed to rise to 100° C. The sulfonation is complete in about 6 hours, when the reaction mixture is transferred to a large basin, diluted with water, and limewater added gradually to neutralize the excess acid. The calcium sulfate and any ferric hydroxide present are removed by filtration and washed with hot water. Sodium carbonate is added to the filtrate until just alkaline to phenolphthalein, and the calcium carbonate is removed by filtration. The filtrate is then evaporated almost to dryness, when the sodium salts of 2-toluenesulfonyl and 4-toluenesulfonyl acids separate out. The total yield of 2-toluenesulfonyl and 4-toluenesulfonyl acids are 95% (340 g). o-sodium tosylate crystallizes with 2H2O as plates. p-sodium tosylate crystallizes with 4H2O as plates or prisms. In order to obtain 2-toluenesulfonyl chloride and 4-toluenesulfonyl chloride the mixture prepared above is treated gradually with an equal weight of finely ground phosphorus pentachloride. When the reaction is complete, cold water is added, the reaction mixture being surrounded by a freezing mixture. The 4-toluenesulfonyl chloride separates as a solid (m.p. 69° C) purified by recrystallization from alcohol. The 2-toluenesulfonyl chloride is an oily liquid (m.p. 10° C), and is separated from the filtrate by means of a separatory  funnel.

Systematic organic chemistry, by W. M. Cumming, 312, 1937.


2-methylbenzenesulfonyl chloride



InChI Key


Canonical SMILES


Depositor-Supplied Synonyms

o-Toluenesulfonyl chloride, 133-59-5, 2-Methylbenzenesulfonyl chloride, 2-methylbenzene-1-sulfonyl chloride, 2-Toluenesulfonyl chloride, Toluenesulfonyl chloride, Benzenesulfonyl chloride, 2-methyl-, o-Tosyl chloride, O-TOLYLSULFONYL CHLORIDE, Toluene-2-sulphonyl chloride, 2-methylphenylsulfonyl chloride, 2-Methylbenzenesulphonyl chloride, 2-methyl-benzenesulfonyl chloride, HDECRAPHCDXMIJ-UHFFFAOYSA-N, SBB046740, tolylsulfonyl chloride, toluenesulfonylchloride, toluenesulphonylchloride, toluene sulfonylchloride, toluenesulfonic chloride, o-toluenesulfonylchloride, AC1L1RDG, AC1Q2ERH, ortho-Toluenesulfochloride, toluene sulphonyl chloride, toluene-sulphonyl chloride, Toluene suiphonyl chloride, ortho-Toluenesulfonchloride, o-Toluenesulphonyl chloride, AC1Q6YM8, SCHEMBL4439, toluene-2-sulfonyl chloride, Ambap133-59-5, chloro(2-methylphenyl)sulfone, ortho-Toluenesulfonyl chloride, KSC174M5T, UNII-341L82E3WG, o-methylbenzenesulfonyl chloride, 557323_ALDRICH, CTK0H4659, HSDB 5618, NSC9354, 2-methylbenzene-sulphonyl chloride, MolPort-001-770-950, o-Toluenesulfonyl chloride (8CI), 2-methylbenzene-1-sulfonylchloride, 341L82E3WG, Benzenesulfonylchloride, 2-methyl-, ALBB-001003, EBD50201, NSC 9354, NSC-9354, EINECS 205-113-0, ANW-74545, AR-1L6980, BBL013805, STK500501, ZINC95707649, 2-Methyl-Benzene-1-Sulfonyl Chloride, AKOS005207130, MCULE-9620469881, QC-1609, VZ34824, AK-47817, AM803157, AN-43718, KB-25521, OR013156, OR214321, SC-22610, AB1003272, KB-232283, RT-000730, TR-051364, BB 0253732, FT-0631774, ST24028099, V2236, 60569-EP2272837A1, 60569-EP2301918A1, 60569-EP2305648A1, 60569-EP2308869A1, 60569-EP2308873A1, A806639, I14-43245, 3B3-063509

Removed Synonyms

null, Toluenesulphonyl chloride, Toluene sulfonyl chloride, CID8623, T0284, 27684-90-8

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  1. girija

    In preparation of 2- toluene sulfonyl chloride, how are the isomers separated? Is para isomer soluble in ortho ?
    Just to confirm- during aqueous and organic separation, density of water is less than the product, so will the lower layer be of organic?

    1. Post author

      If the temperature is maintained properly the 4-toluenesulfonyl chloride is not soluble and separates as a solid, meanwhile, the 2-toluenesulfonyl chloride is an oily liquid (m.p. 10° C), and both compounds could be separated by simple filtration,

      The density of 2-toluenesulfonyl chloride is 1.320 g/mL so the density of water is less than the product during the aqueous and organic separation.

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