Patent GB-818243-A (GB)
Title: Method of making alkyl diphenyl ether sulphonates
IPC: C11D1/24
Filed: 1957-11-19
Abstract: Alkyl diphenyl ether sulphonates, which are water-soluble and have surface-active properties, are produced by reacting 1.8 to 3 molecular proportions of a sulphonating agent, such as chlorosulphonic acid or sulphur trioxide, with one molecular proportion of an alkylated diphenyl ether having attached to each diphenyl ether nucleus an average of 1 to 1.3 alkyl substituents, each comprising from 9 to 15 carbon atoms, the reaction being carried out in a solvent comprising a liquid polychlorinated aliphatic hydrocarbon, such as methylene chloride, carbon tetrachloride, perchloroethylene, sym. tetrachloroethane or ethylene chloride and at a temperature between - 20 DEG  and 60 DEG  C., whereby an alkyl diphenyl ether sulphonic acid containing 1.8 to 2.3 sulphonic groups per diphenyl ether nucleus is obtained, neutralizing the sulphonic acid with an alkali, and separating the resulting sulphonate from the polychlorinated aliphatic hydrocarbon.  The alkyl diphenyl ethers are preferably prepared by reacting tripropylene, tetrapropylene or pentapropylene with diphenyl ether in the presence of aluminium chloride.  In Example 1, diphenyl ether is mixed with powdered anhydrous aluminium chloride.  The mixture is heated, with stirring, to 60 DEG  C., and a tetrapropylene fraction of boiling-range 185-210 DEG  C. is added over a period of 1.5 hours while stirring and maintaining the temperature between 60 DEG  and 70 DEG  C.  The reaction mixture is maintained at this temperature for a further 2 hours, and then the aluminium chloride is removed by washing with water.  The organic liquid is dried and distilled under reduced pressure to separate unreacted diphenyl ether from the alkylated ether.  The latter contains 1.15 C12H25 radicals per diphenyl ether nucleus.  The alkylated ether is dissolved in methylene chloride, and reacted with sulphur trioxide which is also dissolved in methylene chloride, the temperature being maintained at about 26 DEG  C. during the sulphonation.  The sulphonated product is mixed with water, and neutralized with sodium hydroxide solution whereupon an aqueous slurry of the sodium salt of the alkyl diphenyl ether sulphonic acid separates out.  The slurry is dried by spreading it as a thin layer on a heated roll.  The dry product, scraped off the roll, is a free-flowing powder which contains an average of 2 sulphonate groups per ether nucleus.  In Example 2, the starting material is prepared by reacting diphenyl ether with dodecyl bromide.  In Example 5, dodecyl diphenyl ether, having an average of 1.14 dodecyl groups per ether nucleus, is sulphonated with chlorosulphonic acid using methylene chloride as solvent.  Example 7 describes the preparation of sodium mono-(pentapropyl)-diphenyl ether sulphonate which contains an average of 2.17 sulphonate groups per ether nucleus.  Example 9 describes the preparation of sodium mono-(tripropyl)-diphenyl ether sulphonate containing 1.8 sulphonate groups per ether nucleus.  In Example 10, dodecyl diphenyl ether, having 1.2 dodecyl radicals per ether nucleus, is dissolved in methylene chloride and sulphonated with liquid sulphur trioxide under a pressure of 30 p.s.i.g. and a temperature of 60 DEG  C. in a continuous-flow process.  The sulphonic acid is neutralized with sodium hydroxide, and the aqueous slurry of the sodium salt is spray-dried.  Specification 475,955, [Group IV], is referred to.