GB1039804A - Sulfoxidation process - Google Patents

Abstract

Non-aromatic sulphonic acids are prepared by reacting a non-aromatic feed with oxygen and SO2 in molar excess of the oxygen, in the liquid phase, quenching and reducing the so-formed persulphonic acids with an aqueous medium in the presence of SO2, separating an aqueous phase containing the sulphonic acids so produced from unreacted feed, the latter being then contacted with 1 to 100 moles H2SO4 per mole of water contained therein and recycled to the reaction zone, and the product sulphonic acids being recovered from the aforesaid aqueous phase. Suitable non-aromatic feedis C4 to C32 saturated straight-chain hydrocarbons, which may contain secondary carbon atoms, but a tertiary or quaternary carbon content below 10 moles per cent, or may be cyclo paraffins or mono-olefins above about 10 C, or polymerized olefins. The gaseous reactants should be substantially anhydrous and comprise a molar ratio of O2:SO2 of at least 1:2. Pure oxygen, air, or other sources of free oxygen may be used. The reaction is appropriately initiated by ionizing radiation, from an X-ray machine, isotopes, or a b -ray machine, or by ultra-violet light, or chemically by, e.g., azo-compounds, diacylperoxides, ozone, lauryl peroxide, lead acetate, or peroxy-sulphonic acids. Suitable reducing, quenching agents are water or aqueous alcohol in the presence of SO2, at 110 DEG to 125 DEG F. An example of the process employs n-hexadecane as a feed; also two comparative examples are given in which (1) the unreacted n-hexadecane is not treated with H2SO4 before re-cycling, and (2) in which H2SO4 is used instead of an aqueous medium to quench and reduce the persulphonic acid reaction product.