Patent GB-656834-A (GB)
Title: Production of alkyl aromatic sulphonates having surface active properties
IPC: C07C7/171
Filed: 1946-10-23
Abstract: Surface-active alkyl aromatic sulphonates are prepared by alkylating a mononuclear aromatic hydrocarbon containing at least two replaceable nuclear hydrogen atoms with an olefinic naphtha fraction boiling within the range of from 160 DEG  to 240 DEG  C., sulphonating resultant alkylate comprising alkyl aromatic hydrocarbons containing an alkyl aroup having from 10 to 16 carbon atoms, converting the sulphonic acid formed thereby into a sulphonate salt and excluding from the sulphonation reaction substantially all impurities consisting of condensed ring aromatic hydrocarbons and nitrogen- and sulphur-containing organic compounds originating in said olefinic naphtha fraction by treating said olefinic naphtha fraction with one or more agents selected from the group consisting of liquid extraction and solid absorptive agents capable of effecting the separation of one or more of said impurities from said naphtha in such manner that all of said impurities contained in the naphtha are removed therefrom and subjecting the thus treated naphtha to the alkylation treatment, and/or by applying a purification treatment to said alkylate by means of a fractional distillation or a solvent extraction treatment and fractional distillation of the hydrocarbon reaction product mixture of the alkylation treatment in such manner that said alkylate is obtained as a distillate fraction substantially free from all of said impurities.  The mononuclear aromatic hydrocarbons are benzene and its homologues containing at least two replaceable hydrogen atoms and include mono- or poly-alkyl benzenes in which the alkyl groups contain less than 6 carbon atoms and many examples are given.  The olefinic naphtha fraction may be a thermally cracked or reformed petroleum distillate of boiling range 160-240 DEG C.; preferably there will be present in the olefines in said fraction at least 30 per cent of C10-C12 olefines and not more than 20 per cent of olefines having more than 15 carbon atoms per molecule. The purification of the olefinic fraction may be effected by a solvent extraction procedure or treatment with a solid selective adsorption agent wherein either the desired olefinic hydrocarbons or the undesired impurities are selectively adsorbed from the fraction and removed.  Selective solvents mentioned are nitroparaffins wherein generally the carbon-chain length does not exceed C6 to C8, organic acids such as acetic and propionic acids, such ethers as the aliphatic ethers of ethylene and diethylene glycols, amino alcohols such as mono- or di-ethanolamine and saturated and unsaturated aliphatic alcohols especially those containing about 5 to 10 carbon atoms including dipropylene glycol, hexanol and octanol; the preferred solvents are the ethers, nitroparaffins and amino alcohols which are, with or without water, generally immiscible with the hydrocarbon layer and remove aromatics; the alcohols and organic acids require to be washed from the raffinate and extract layers with a secondary solvent, e.g. water.  The solid adsorbent is, preferably, one which removes the aromatics and may remove some or all of the nitrogen- and sulphur-impurities rather than one which selectively removes the olefines; the treated olefinic fraction is then washed with a liquid extraction agent, e.g. water or aqueous solutions of bases and acids, if necessary, to remove any residual nitrogen- and sulphur-containing organic compounds.  Silica, especially in the activated form, is given as an example of a selective solid adsorptive body for the impurities.  The alkylate purification, by fractionation alone or aided by solvent extraction, serves also to remove condensed-ring alkyl aromatics formed during the alkylation. The alkylate purified by fractional distillation may be further purified by an extraction treatment with minor proportions of 80 to 96 per cent sulphuric acid.  In the alkylation, it is preferred to employ a molar excess of the aromatic hydrocarbon to prevent poly-alkylation of the aromatic hydrocarbon; molar ratios of 2 : 1 up to about 20 : 1 are mentioned.  Suitable alkylation catalysts named are sulphuric acid, 90-100 per cent hydrogen fluoride, boron fluoride, aluminium chloride, and the hydrocarbon (sludge) complexes, or the "ansolvo" acid complexes, with or without a hydrogen halide promotor such as hydrogen halide when utilizing aluminium chloride. When hydrogen fluoride is used, the alkylate may contain alkyl fluorides in minor amounts; these may be removed by passing the alkylate over a defluorinating agent such as aluminium, iron, copper or certain oxides, e.g. alumina generally at a temperature of about 100-250 DEG  C.  Sulphonation is normally effected with sulphuric acid, but chlorsulphonic acid and mixtures of sulphuric acid and boron trifluoride may also be used.  The resulting sulphonic acids may then be neutralized with an aqueous solution of a base followed by evaporation and drying yielding the alkyl sulphonates.  However, preferably, the sulphonation product is cooled and treated with an organic liquid which is a selective solvent for the alkyl aromatic sulphonic acid and unreactive towards the sulphuric acid present to remove the sulphonic acid from the sulphonation mixture in substantially pure form.  The sulphonation mixture separates on settling into layers; preferably, the sulphonic acid extraction is first applied to the bottom spent sulphuric acid layer and the selective solvent now containing some sulphonic acid is then used to extract the upper sulphonic acid layer.  Usually on settling a third layer, being a top layer of hydrocarbons, forms and this layer may be recycled in the sulphonation process; its formation is facilitated by addition of water or aqueous sulphuric acid.  The intermediate sulphonic acid layer may be neutralized directly, but, preferably, the sulphonic acid is first selectively extracted and then neutralized.  Selective solvents mentioned are non-olefinic hydrocarbons and saturated halogenated hydrocarbons preferably boiling below about 200 DEG  C., for example, paraffinic and aromatic hydrocarbons including paraffin-containing fractions of hydrocarbon oils, such as n-butane, n-pentane, hexane, benzene, toluene, kerosine and naphtha fractions of petroleum distillates and halogenated paraffins such as chloroform, carbon tetrachloride and dichloroethane.  Neutralization of the sulphonic acid is preferably effected when the latter is still dissolved in the selective solvent. An aqueous solution of a basic reagent is employed and the resulting sulphonate salt separates out as an aqueous layer which is decanted off and evaporated to dryness. Spray-drying results in products having the form of spherically-shaped particles.  Suitable bases are the alkali metal hydroxides, ammonia and organic amino compounds in particular methyl-, ethyl- and propyl-amine and hydroxy amines such as mono- or diethanolamine.  The products find particular application as soap substitutes (see Group III).  A continuous process is described with reference to a flow sheet (not shown) wherein toluene is alkylated with a naphtha fraction of boiling range 175-210 DEG  C. In examples: (1) a naphtha fraction B.P. 180.-218 DEG  C. from a thermally cracked gas oil distillate of a Pennsylvania crude oil is extracted with a solvent comprising the methyl ether of ethylene glycol and water, the extract removed and the raffinate again extracted; after nine such extractions, the raffinate is reacted with benzene using hydrogen fluoride as catalyst, the alkylate is defluorinated, fractionally distilled, a fraction boiling from 275-384 DEG  C. is further purified by several treatments with sulphuric acid, then sulphonated, allowed to settle and the upper sulphonic acid layer is neutralized with sodium hydroxide, evaporated to dryness, and the sodium alkyl benzene sulphonates extracted with ethanol.  (2) Benzene is alkylated with an unextracted naphtha fraction of boiling range 180-216 DEG  C. and the alkylate washed free from acid, defluorinated and fractionally distilled and selected intermediate alkylate fractions are treated thereafter as in (1). (3) Toluene is alkylated and the product further treated to obtain sodium alkyl toluene sulphonates as in (2).  Specifications 416,379 and 539,281 are referred to.  The Specification as open to inspection under Sect. 91 refers broadly to removing condensedring aromatic hydrocarbons and nitrogen- and sulphur-containing compounds from the said olefinic naphtha fraction or the alkylate prior to the sulphonation reaction.  This subject-matter does not appear in the Specification as accepted.ALSO:Surface-active compositions comprise alkyl aromatic sulphonates obtained by alkylating a mononuclear aromatic hydrocarbon containing at least two replaceable nuclear hydrogen atoms with an olefinic naphtha fraction boiling within the range of from 160 DEG  to 240 DEG  C., sulphonating resultant alkylate comprising alkyl aromatic hydrocarbons containing an alkyl group having from 10 to 16 carbon atoms, converting the sulphonic acid formed thereby into a sulphonate salt and excluding from the sulphonation reaction substantially all impurities consisting of condensed-ring aromatic hydrocarbons and nitrogen- and sulphur-containing organic compounds originating in said olefinic naphtha fraction in specified manner (see Group IV (b)).  The alkali metal, ammonium and amine salts are mentioned, including the short-chain aliphatic amine and hydroxy-amine, e.g. mono-and di-ethanolamine, salts.  They may be used alone or in conjunction with detergency-increasing assistants such as sodium sulphate, sodium benzene sulphonate, sodium carbonate, trisodium phosphate and sodium pyrophosphate.  They may be used in deterging, wetting and penetrating processes, and have utility in sizing, dyeing and tanning operations.  Specifications 416,379 and 539,281 are referred to.$$$