GB669313A - A process of producing an alkyl aryl sulphonate detergent - Google Patents

Abstract

Alkyl aryl sulphonate detergents are obtained from an olefine-containing hydrocarbon fraction boiling under normal pressures between 300 DEG and 600 DEG F. and consisting essentially of the reaction products which have been obtained in the Fischer-Tropsch synthesis of hydrocarbons by substantially completely removing oxygenated organic compounds especially carbonyl compounds from said hydrocarbon fraction, then alkylating benzene or toluene with the olefine containing hydrocarbon fraction to form aryl alkanes and sulphonating said aryl alkanes. The oxygenated compounds which are removed are principally aldehydes or ketones and possibly certain organic acids. These may be removed by various ways, e.g. by treating the olefine stock with hot caustic solutions, or with sodium bisulphite, and further removal of the oxygenated compounds may be effected in various ways, e.g. by extraction with solvents. The remaining oxygen compounds are principally higher boiling-point alcohols which may be extracted by solvents such as methanol or by azeotropic distillation, e.g. using butylene glycol as the third phase. Another method is to use boric acid solutions to esterify the higher alcohols, the esters formed being readily separated by distillation. It is preferred to purify the olefins by adsorbents such as activated carbon or silica gel. By silica gel adsorption it is possible to obtain a separation of olefins and paraffins from the Fischer - Tropsch hydrocarbons with complete removal of oxygenated compounds and it is also possible to separate the olefins from aromatic hydrocarbons. In an example, Fischer-Tropsch hydrocarbons are obtained by passing hydrogen and carbon monoxide over an iron alkali catalyst (a catalyst consisting of metallic iron and containing a small amount of an alkali metal compound or an alkaline earth compound which acts as an activity promoter) at a temperature of about 600 DEG F. and 300 pounds pressure. The gases are then cooled to 350 DEG F. to remove waxes and then to about 100 DEG F. to separate an oil fraction from the water produced in the process. The hydrocarbons used are separated from the waxes and the oil fraction and are then fractionally distilled to give a suitable olefin stock containing between 8 and 20 carbon atoms. It is desirable, however, to use a fraction boiling between 350 and 500 DEG F. in which about 95 per cent of the olefinic constituents contain between 12 and 15 carbon atoms. The fraction is then passed through a column of silica gel. The bromine number of the material passing through the column increases until about 60 per cent of the material has passed through the column and this 60 per cent of the material is separated as the olefin stock (consisting solely of olefins and paraffins) for preparing monophenyl alkanes. Alkylation may be carried out with a Friedel-Crafts type condensation catalyst, e.g. AlCl3, H2SO4, HF, BF3 or mixtures of BF3 and HF. In the example hydrogen fluoride is used and the alkylation is effected at 100 DEG F. The alkylation product is fractionally distilled, the fraction boiling in the range 525 DEG to 650 DEG F. at atmospheric pressure being retained for sulphonation. The sulphonation is effected with 20 per cent fuming sulphuric acid and the product is then neutralized with sodium hydroxide to produce a mixture of sodium sulphonates and sodium sulphate. Toluene may be alkylated in the example, instead of benzene. U.S.A. Patent 2,275,312 is referred to.