Patent GB-645268-A (GB)
Title: Process for production of oxygenated sulphur compounds
IPC: C07C317/00
Filed: 1947-08-28
Abstract: Organic compounds containing sulphur chemically bound to oxygen are manufactured by contacting an organic sulphur compound of the formula R1SnR2 (wherein R1 and R2 represent hydrocarbon radicals, which may contain substituents, or jointly comprise a bivalent hydrocarbon radical, and n is 1 or 2) with a gas containing free oxygen in the presence of a catalytic quantity of a nitrogen oxide selected from NO, NO2, N2O3, N2O4 and N2O5.  When sulphonic acids are desired, water must also be present in an amount not exceeding about 20 per cent of the amount of organic sulphur compound, preferably (to obtain substantially anhydrous sulphonic acids) in an amount not substantially exceeding 1 mol. per mol. of sulphonic acid anhydride produced by the oxidation, and the reaction in this case should be conducted at a temperature below about 300 DEG  F., preferably at about 20-250 DEG  F., especially 50-150 DEG  F.  Water and oxides of nitrogen may be provided simultaneously by adding nitric acid to the reaction mixture. Starting materials in which n is 2 (of which dialkyl disulphides, and especially those in which at least one alkyl group is primary or secondary, are preferred) yield, depending on the temperature, reaction period and amount of oxygen employed, compounds of the formul  <FORM:0645268/IV (b)/1> Compounds in which n is 1 yield sulphoxides and sulphones, the latter resisting further oxidation.  In examples: (1) a mixture consisting chiefly of dialkyl disulphides containing 4 and 5 carbon atoms in the molecule (obtained as a product of a caustic-solutizer gasoline extraction in which the caustic is regenerated with air) is treated at room temperature (rising later to 160 DEG  F.) in the liquid phase with oxygen, NO2 and water to produce anhydrous alkylsulphonic acids and other oxygenated sulphur compounds; n-butyl disulphide similarly yields anhydrous butylsulphonic acid; (2) di-isobutyl disulphide is passed downwards through a packed tower against a stream of oxygen containing 5 per cent of NO2, with the addition of water, producing isobutanesulphonic acid.  Additional starting materials specified are: dimethyl, dipropyl, methyl butyl, ethyl propyl, dicresyl, dicyclohexyl, dicotyl and dilauryl disulphides, dimethyl, di-isopropyl, dicetyl, methyl butyl and ethyl isopropyl sulphides, thiophene, dimethylthiophene, dihydrothiophenes, thiophane and dimethylthiophane, also compounds containing unsaturated linkages or substituents (which may be oxidized in the process), e.g. halogen atoms or nitro, amino, amido, substituted amino or amido, carboxyl or hydroxy groups.  The oxidation products are useful as intermediates for further conversion, e.g. the alkyl-sulphonic acids may be esterified with olefines.  The alkylsulphonic acids may also be used alone or in conjunction with hydrogen fluoride, boron trifluoride, fluorsulphonic acid or chlorosulphonic acid, as catalysts for reactions in which sulphuric acid is normally employed, e.g. hydration of olefines (e.g. of propylene to isopropyl alcohol), alkylation of paraffins with olefines (e.g. of isobutane with butylenes), polymerization of olefines or isomerization of paraffin hydrocarbons.  The Specification as open to inspection under Sect. 91 comprises also the oxidation of polysulphides (n=3-6 in the general formula above).  This subject-matter does not appear in the Specification as accepted.