Patent GB-654464-A (GB)
Title: Improvements in or relating to the production of sulphones
IPC: C07D333/48
Filed: 1948-01-28
Abstract: Cyclic sulphones are made by subjecting an oil recovered from sulphuric acid spent in the treatment of sulphur-containing mineral oil, or mineral oil fractions, to mild oxidizing conditions.  The latter term is defined with reference to the use of an oxidizing agent so as to effect complete oxidation of the -S- group without decomposition of the heterocyclic ring structure.  Polymethylene sulphides obtained from the recovered oil by fractional, steam or extractive distillation may be treated.  A suitable recovered oil is obtained by refining an aromatic concentrate from petroleum oil, e.g. a straight run benzine cut 100-160 DEG  C. is treated with sulphur dioxide and the aromatic concentrate acid refined with 90-98 per cent sulphuric acid when after dilution with water the oil layer is recovered and a number of polymethylene compounds may be obtained therefrom, e.g. tetramethylene, 2- and 3-methyltetramethylene, pentamethylene and methylpentamethylene sulphides boiling in the ranges of 115-125 DEG  C., 130-135 DEG  C., 135-139 DEG  C., 139-145 DEG  C., and 145-152 DEG  C. respectively preferably by fractionation in a column of at least 100 theoretical plates operated at a reflux ratio of at least 50 : 1.  Preferably, fractionation is preceded by a purification step to remove the sulphur compounds from associated hydrocarbons as by e.g. absorbing in concentrated sulphuric acid diluting with water and steam distilling.  Oxidizing agents and conditions specified are treatment with an alkaline aqueous solution of sodium hypochlorite or sodium or potassium permanganate or with hydrogen peroxide in acetic acid.  The sulphones alone or mixed are useful in liquid-liquid extraction and extractive distillation processes.  In examples: (1) polymethylene sulphide fractions obtained as above were again purified by forming the mercury chloride complex and decomposing by refluxing with dilute hydrochloric acid; (2) pentamethylene sulphide is refluxed with hydrogen peroxide in glacial acetic acid for 3 hours, acid removed by distillation in vacuo finally by distillation with ethyl alcohol and pentamethylene sulphone recovered; (3) a benzine extract tar oil is steam distilled and the volatile portion fractionally distilled to give four fractions of boiling range 86-143 DEG  C., 143-159 DEG  C., 159-178 DEG  C. and 178-222 DEG  C., the first fraction being oxidized with hydrogen peroxide in glacial acetic acid at below 40 DEG  C. when excess peroxide is removed by refluxing and acetic acid by distillation in vacuo and a mixture of cyclic sulphones obtained; (4) the second fraction of (3) is oxidized with aqueous sodium hypochlorite at 5-20 DEG  C. when excess hypochlorite is removed with sulphur dioxide, the solution acidified with hydrochloric acid, evaporated to dryness under reduced pressure, the solid cake is extracted with acetone or methyl ethyl ketone and after removal of the solvent the cyclic sulphone mixture is obtained containing chlorinated impurities which are removed by zinc and acetic acid reduction; and in (5) fraction three of (3) is oxidized with potassium permanganate in aqueous sodium hydroxide solution at 20 DEG C., after 18 hours sulphur dioxide is added to remove excess permanganate and manganese dioxide and the product worked up as in (4).