Patent GB-672640-A (GB)
Title: Improvements in or relating to a process for the production of a sulfonic anhydride and the product resulting therefrom
Filed: 1947-09-11
Abstract: Sulphonanilides derived from sulphonic anhydrides of the general formula (RSO2)2O, wherein R is an alkyl, cycloalkyl or aralkyl radical (see Group IV (b)), may be used as plasticizers for synthetic resins.  Thus, n-butane-sulphonanilide is compatible with vinyl chloride resins and cellulose acetate.  The Specification as open to inspection under Sect. 91 defines R as an organic radical, e.g. a phenyl, xylyl, tolyl or naphthyl radical.  This subject-matter does not appear in the Specification as accepted.ALSO:Sulphonic anhydrides, sometimes together with sulphonic acids, are prepared by oxidizing an anhydrous charging stock essentially comprising a dialkyl sulphur compound other than a di-tertiary alkyl disulphide as the only oxidizable component, said dialkyl compound being selected from disulphides, disulphoxides and disulphones (the term "alkyl" being used to include the cycloalkyl and aralkyl radicals), with a gas containing free oxygen in the presence of a catalytic quantity of a nitrogen oxide selected from the group consisting of <PICT:0672640/IV (b)/1> NO, NO2, N2O3, N2O4 and N2O5 in an oxidation zone while excluding water from said zone.  The feed stock may be a single dialkyl sulphur compound or a mixture of such compounds and substances not appreciably oxidized under the reaction conditions may be present. Dimethyl, dipropyl, methyl butyl, ethyl propyl, dicyclohexyl, dicetyl, dilauryl and benzyl methyl disulphides are mentioned; a preferred feedstock comprises the dialkyl disulphides obtained as by-product in the caustic solution extraction of mercaptans from petroleum distillates and regeneration of the caustic solution, this extraction method being described in detail.  The oxidation of the dialkyl sulphur compounds may be effected in the vapour phase but is normally carried out in liquid phase, if necessary, under pressure.  Temperatures are normally about 0 DEG  to 150 DEG  C. The nitrogen oxide catalyst is employed generally in amounts of between 1 and 10 per cent of the total volume of oxygen absorped. The process may be effected batchwise or semi- or wholly continuously; several forms of apparatus are described.  In one form, Fig. 1 (not shown), the reactor comprises a vertical closed tower provided with an upper packed contacting zone A and a similar lower zone B.  Feed-stock is fed down through zone A, maintained at 0-50 DEG  C., against a counterflow of oxidizing gases and catalyst whereby the stock is 50-70 per cent oxidized and thereafter flows through zone B maintained at 50-150 DEG  C., to which zone air and nitrogen oxide is supplied, the final sulphonic anhydride content of the stock being about 80-95 per cent.  Examples are given of processes employing apparatus (Fig. 2) wherein oxidizing gas and nitrogen oxide are fed via pipes 100, 101 into the bottom of a gas lift tube 102 where they meet a liquid stream of dialkyl sulphur compound charging stock.  The gases exert a gas lift on the charging stock which passes up tube 102 whereupon the whole mixture flows into the top of reactor 103.  Partial oxidation occurs in tube 102 and is completed in reactor 103 during the concurrent flow of feed stock, catalyst and oxidizing gas down the reactor; all or part of this reactor may be packed with a contacting material.  Spent gases leave reactor 103 via line 106 to a separator 108 which may be cooled sufficiently to separate out the nitrogen oxide catalyst in liquid form for re-use.  The oxidized feed-stock passes to a separator 113 from which it may be recycled through gas lift tube 102 or withdrawn from the system via line 116.  Charging stock may be fed in via line 117.  If desired, oxidation systems as shown may be used in series or parallel; thus a two-stage oxidation may be effected operating the first reactor at about 0-50 DEG  C. and the second in series at 50-150 DEG  C.  In the examples: (1) diethyl disulphite is oxidized with dry air containing NO2, yielding a yellow oil which is shaken with cold water to separate ethane sulphonic anhydride (75 per cent) from the corresponding soluble sulphonic acid; (2) dimethyl disulphide is treated similarly, the product forming white crystals on cooling which are fused and air blown to remove NO2, yielding a mixture of methane sulphonic anhydride (about 78 per cent) and the corresponding acid; (3) n-butyl disulphide oxidized similarly yields a product containing 62 per cent butane sulphonic anhydride identified by reaction with p-toluidine in benzene with formation of butanesulphon - p - toluidide-this reaction is selective for the anhydrides in presence of the corresponding alkane sulphonic acids; (4) a charging stock comprising methyl, ethyl and isopropyl disulphides obtained as by-product in extraction of mercaptans from a petroleum naphtha is similarly oxidized yielding a product containing 35 per cent sulphonic anhydride determined by reaction of the product with aniline in ether forming sulphonanilides.  The products react with warm water to form sulphonic acids.  The sulphonic anhydrides react with inorganic alkaline materials to form salts, e.g. with sodium hydroxide to form sodium sulphonates; they also react with other alkaline reagents such as sodium methylate or ethylate, sodium alkylamides or arylamides or sodamide.  The anhydrides react with alcohols to form sulphonic esters and acids, e.g. ethanol, n or iso-propanol, butanols, ethylene chlorhydrin, ethylene cyanohydrin and b -nitroethanol. Reaction of the anhydrides with ammonia and amines produces ammonium salts or amides, the reaction being effected, if desired, in a solvent such as water, alcohol or benzene; the sulphonamides may be used as froth flotation agents (see Group II), reference being made especially to those of the general formula R1SO2NHR2, where R1 is a C1-12 alkyl group and R2 is a hydrocarbon group having between 1 and 12 carbon atoms, e.g. a phenyl or chlorphenyl group.  The sulphonanilides may also be used as plasticizers for rubber and synthetic resins (see Group II) and as solubilizers in extraction of mercaptans from petroleums with aqueous caustic (see Group III).  The sulphonic anhydrides react with alkanol-amines to form amides or amine esters which may be used in the production of wetting-agents or plasticizers.  The anhydrides react with active inorganic halogen compounds such as thionyl chloride, PCl5 or COCl2 to form sulphonyl halides.  Alternatively, the sulphonyl halides together with corresponding sulphonic acids or salts thereof, may be formed by reacting the anhydrides with a halogen acid such as hydrogen chloride, bromide or fluoride, or with a salt of a halogen acid, e.g. sodium chloride; thus, hydrogen chloride may be passed through a liquid sulphonic anhydride at about 20-130 DEG  C. under such pressure that the resulting sulphonyl chloride distils off as it is formed.  The sulphonic anhydrides also react with organo-metallic compounds such as Grignard reagents, metal alkyls or aryls and sodiomalonic ester.  The sulphonic anhydrides may be used as solvents for metal halides containing an electron-deficient metal atom, e.g. aluminium chloride and BF3, by forming complexes therewith. The sulphonic anhydrides may also be employed as solvents for the chlorination or nitration of organic materials and, alone or in admixture with the corresponding sulphonic acids, as selective solvents for aromatic hydrocarbons, for example those contained in petroleum naphtha (see Group III) and as drying agents for various gases (see Group XIII).  The Specification as open to inspection under Sect. 91 defines the material to be oxidized as a substantially anhydrous charging stock comprising an organic sulphur compound selected from the group consisting of disulphides, disulphoxides and disulphones and refers to the use of aromatic disulphides such as diphenyl, phenyl tolyl, phenyl xylyl and phenyl naphthyl disulphides.  This subject-matter does not appear in the Specification as accepted.ALSO:Sulphonic anhydrides of the general formula (RSO2)-O where R is an alkyl, cycloalkyl or aralkyl group, alone or in admixture with the corresponding sulphonic acids may be used as selective solvents for aromatic hydrocarbons and thus, for example, a petroleum naphtha containing aromatic and paraffinic hydrocarbons may be treated with alkane sulphonic anhydrides to selectively remove the aromatics.  The alkane sulphonic anhydrides may be converted into sulphonanilides which may be used as solutizers in the extraction of mercaptans from petroleum products such as gasoline with aqueous caustic.  The anhydrides are prepared by oxidation of the corresponding disulphides, disulphoxides and disulphones (see Group IVb) the following starting materials being mentioned: dimethyl, diethyl, dipropyl, di-n-butyl, methyl butyl, ethyl propyl, dicyclohexyl, dicetyl, dilauryl and benzyl methyl disulphides and the mixed sulphides obtained as by-product in the aqueous caustic extraction of mercaptans from petroleum.  The Specification as open to inspection under Sect. 91 defines R in the above formula as being an organic radical, and gives phenyl, tolyl, xylyl and naphthyl radicals as further examples. This subectmatter does not appear in the Specification as accepted.ALSO:A bleaching agent for flour consists of a white crystalline product comprising ethane sulphonic anhydride and nitrogen dioxide, the latter being evolved when the crystals contact water or moist air.  The crystals are obtained as a by-product in the oxidation of ethyl disulphide by air in presence of the nitrogen oxide (see Group IV(b)).ALSO:Froth flotation additives comprise alkane-sulphonamides especially those having the general formula R1 SO2 NHR2 where R1 is a C1-12 alkyl group and R2 is a hydrocarbon group having between 1-12 carbon atoms; preferably R1 or R2 contains at least 6 carbon atoms and R2 is preferably an aryl group such as a ph