Patent GB-685621-A (GB)
Title: Improvements in or relating to the production of surface active agents
IPC: C07C303/24
Filed: 1949-07-19
Abstract: Surface-active agents are prepared by reacting an alkyl hydroperoxide having, in the molecule, a carbon chain of at least 10 carbon atoms and/or an alkyl substituted naphthene hydroperoxide with sulphur dioxide at a temperature within the range -10 DEG  to +60 DEG  C., whereby an alkyl hydrogen sulphate and/or an alkyl naphthene hydrogen sulphate is produced and thereafter reacting the hydrogen sulphate or sulphates with ammonia, a metal base, an organic base or other base to form the corresponding sulphate salt or salts.  The sulphur dioxide may be used in liquid or gaseous form and at reduced, normal or elevated pressure; it may be reacted directly with the hydroperoxide or with the latter dispersed in an aqueous medium or in the presence of an inert liquid diluent, e.g. saturated hydrocarbons, alcohols and glycols. Suitable alkyl-hydroperoxides are those having 10-20 carbon atoms, and satisfactory naphthene hydroperoxides have 4-16 carbon atoms in the side chain.  The hydroperoxides may be prepared by treating paraffins having a carbon chain of at least 10 carbon atoms or alkyl naphthenes with oxygen or gaseous mixtures containing oxygen aided if desired by an aerial oxidation catalyst such as an organic peroxide, e.g. tertiary butyl hydroperoxide, or a small proportion of a previous batch of the oxidized products. Preferably, the oxidation is carried out to achieve a conversion of less than 25 per cent.  The resulting oxidate may be used as such in the formation of the sulphates or after refinement.  Thus, the oxidate may be concentrated by distilling off at least part of the unreacted hydrocarbon; or by extracting the hydroperoxide by means of a polar solvent such as methanol, ethanol or higher alcohols, glycols or "Cellosolve" (Registered Trade Mark) and then, if desired, recovering the hydroperoxides from the extract by distilling off the solvent or precipitating the hydroperoxide by addition of aqueous medium; or by treating the oxidate with aqueous alkali until neutralized, whereupon carboxylic acids present are extracted into the aqueous layer or by using a large excess of alkali on the oxidate before or after such removal of carboxylic acids, whereby the hydroperoxides are extracted by the aqueous alkali from which they are recovered by subsequent acidification.  Suitable oxidation feedstocks are refined kerosine, hydrogenated Fischer-Tropsch oils, petroleum waxes, and wax-cracking product fractions, shale oil fractions and crude hydrocarbon synthesis fractions which may first be treated to remove olefins.  A flow sheet (not shown) illustrates suitable apparatus for continuous production of the sulphates from the hydrocarbons.  In typical examples: (1) an aromatic-free kerosine B.P. 220-230 DEG  C., is oxidized by air at 130 DEG  C. in presence of tertiary butyl hydroperoxide, the resulting oxidate is alkali washed to remove acids, giving an oil containing 8 per cent peroxide; SO2 is bubbled through the stirred oil at -5 DEG  to 0 DEG  C., then aqueous caustic soda is added to neutralize and the resulting aqueous layer containing alkyl sulphates is washed with petroleum ether and evaporated to dryness; (5) a crude air oxidate of tetradecane containing 7 per cent tetradecane hydroperoxide is stirred with water, SO2 bubbled through at 6-10 DEG  C., the aqueous phase then separated and worked up as in (1), yielding a solid mixture of tetradecyl sodium sulphate and some sodium carboxylic acid salts; (8) a kerosine cut, B.P. 210-220 DEG  C., is oxidized with air at 140 DEG C., extracted with methanol to form a methanol extract containing 4.5 per cent hydroperoxides which is reacted with SO2 at 20-40 DEG  C., neutralized with caustic soda and the sodium alkyl sulphates recovered therefrom; (10) the methanol extract of (8) is concentrated to 33.2 per cent hydroperoxide content, dispersed in water, reacted with SO2 at 20-30 DEG  C. with stirring, and either neutralized with aqueous alkali, supernatant oil removed and the aqueous layer evaporated to dryness, or separated into an oil layer and an aqueous layer of alkyl acid sulphates and the latter neutralized with (11) magnesium carbonate, (12) aqueous ammonia or (14) aqueous triethanol amine and dried; (13) a methanol extract similar to that of (10) is treated in the same manner using pyridine as neutralizing agent but the oil layer is removed after neutralization.  A comparative experiment (7) is described wherein a kerosine hydroperoxide is reacted with SO2 at about 100 DEG  C. and an inferior surface-active product results.