Enichem Augusta S.p.a.

Eniricerche S.p.a.

Eniricherche S.p.a.

Cosimo Franco

Lucio Faggian

Edoardo Platone

Enrico Borgarello

Gerardo Carrillo

Maurizio Castellano

Luciano Cavalli

Artemio Gellera

Onorio Gallistru

Giuseppe La Torre

Camilla Maraschin

The invention is concerned with an improved process for preparing paraffin-sulfonic acids containing from 10 to 20 carbon atoms, as well as their salts. The process comprises the initial reaction of sulfo-oxidation of the concerned mixture of n-paraffins, the removal of unreacted n-paraffins from the reaction mixture, the removal of the excess of SO.sub.2 from said mixture, and the removal from the reaction mixture of the therein formed sulfuric acid, with the simultaneous recovery of the end product. After the removal of SO.sub.2, to the reaction mixture hydrogen peroxide is added and the so obtained solution is submitted to one treatment selected from among the following treatments:

Process for preparing paraffin-sulfonic acids

The mixture from which sulphuric acid must be separated according to the present invention are those which derive from the sulphoxidation of (C.sub.12 -C.sub.8)-n-paraffins with SO.sub.2 and O.sub.2 in the presence of water and of U.V. light at a temperature comprised within the range of from 25 to 50.degree. C., after the removal of n-paraffins, which separate spontaneously, and of SO.sub.2 excess. In order to remove said sulphuric acid, the refined mixture, possibly diluted with water, is mixed with one or more halogenated solvents, the separation being obtained of water and sulphuric acid from the refined mixture, to the total mixture (with the two phases) a cosolvent is added, which is constituted by alcohols or ethers, with the separation being obtained of a phase constituted by H.sub.2 O and H.sub.2 SO.sub.4, which is removed. The residual organic phase, practically free from sulphuric acid, is submitted to the removal of solvents and cosolvents by means of conventional techniques.

Process for the separation of sulphuric acid from aqueous mixtures

The purpose of the process of the present invention is to remove excess sulfuric acid from a mixture of paraffin-sulfonic acids free or substantially free, from paraffins. In order to remove said sulfuric acid, according to the process of the present invention, the paraffin-sulfonic acid mixture is mixed with one or more halogenated solvent(s), possibly in mixture with sulfuric acid to form a two phase mixture consisting of an organic phase containing paraffin-sulfonic acids dissolved therein and an aqueous phase substantially containing sulfuric acid. The organic phase is then treated with sulfuric acid and the organic phase and aqueous phase are then separated and the organic phase is submitted to evaporation, for the removal of the halogenated solvent(s), and with the concentrated paraffin-sulfonic acids being obtained.

Process for the separation of sulfuric acid from aqueous mixtures of

Mixtures of C.sub.12 -C.sub.18 n-paraffins with paraffinsulfonic acids having the same number of carbon atoms, water and sulfuric acid, and obtained by sulfoxidation of said paraffins with sulfur dioxide and oxygen in the presence of water and ultraviolet radiation are stripped of their excess sulfur dioxide and decanted to separate most of the paraffins, and obtain a residual mixture. The residual mixture is fed with sulfuric acid until a two-phase system forms or at least until the mixture becomes turbid, and the turbid mixture or that floating on the heavy water-sulfuric acid phase is extracted with supercritical carbon dioxide, which removes with it the paraffins, which can be reused in the sulfoxidation process.

Process for extracting paraffins from their mixtures with

In preparing alkanesolfonic acids by sulfoxidation of n-paraffins containing between 12 and 18 carbon atoms, using ultraviolet radiation to initiate the reaction (light-water process), a mixture is obtained which spontaneously allows a substantial part of the unconverted n-paraffins to phase separate from a phase containing the remainder of the reaction mixture containing the alkanesulfonic acids together with water, sulfuric acid and n-paraffins. The remainder of the mixture is fed with one or more alcohols having four or less than four carbon atoms, preferably isopropanol, to form a two-phase mixture. The two-phase mixture is extracted with supercritical carbon dioxide, which extracts the n-paraffins, these being recycled to the sulfoxidation process. The paraffin-free product is suitable for preparing alkane-sulfonates of the desired type by neutralization with suitable bases.

Process for extracting paraffins from their mixtures with alkanesulfonic

Mixtures of C.sub.12 -C.sub.18 n-paraffins with paraffinsulphonic acids having the same number of carbon atoms, water and sulphuric acid, and obtained by sulphoxidation of said paraffins with SO.sub.2 and O.sub.2 in the presence of water and UV radiation are stripped of their excess SO.sub.2 and decanted to separate most of the paraffins, and obtain a residual mixture. The residual mixture is dehydrated according to the invention until a two-phase system forms or at least until the mixture becomes turbid, and the dehydrated mixture either as such or after separating the heavier phase consisting of water and sulphuric acid is extracted with supercritical CO.sub.2, which removes with it the n-paraffins, these being reused in the sulphoxidation process.

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Locri, Italy

Cosimo Franco