| 摘要 |
1. CASE 2438 "PROCESS FOR THE SEPARATION OF SULPHURIC ACID FROM AQUEOUS MIXTURES THEREOF WITH PARAFFIN-SULPHONIC ACIDS" The mixtures from which sulphuric acid must be separated according to the present invention are those which derive from the sulphoxidation of (C12-C18)-n-paraffins with SO2 and O2 in the presence of water and of U.V. light at a temperature comprised within the range of from 25 to 50 C, after the removal of n-paraffins, which separate spontaneously, and of SO2 excess, and after being submitted to one of the following treatments: a) dehydration, by known systems of the residual mixture, at least until said mixture becomes cloudy (due to the formation of a biphasic system), extraction of not-sulphoxidated paraffins from the dehydrated, cloudy mixture, or from the supernatant phase of the biphasic system, with supercritical CO2, at a temperature comprised within the range of from 32.degree.C to 80.degree.C, under a pressure comprised within the range of from 75 to 350 bars, and with a CO2/paraffinsulphonic acids weight ratio of from 1/1 to 50/1. b) addition of H2SO4 to the residual mixture, at least until said mixture becomes cloudy (due to the formation of a biphasic system), extraction with 2. supercritical CO2, from the cloudy mixture, or from the supernatant phase of the biphasic system, of the residual paraffins under such conditions as shown under (a); c) addition to the residual mixture of an aliphatic alcohol containing a number of carbon atoms lower than, or equal to, 4, preferably isopropanol, until a biphasic mixture is formed, extraction from the biphasic mixture of the residual paraffins, with supercritical CO2, under such conditions as reported under (a). The mixture of paraffin-sulphonic acids free, or substantially free, from paraffins obtained by means of the above disclosed treatments from (a) to (c) (the "refined mixture") still contains, besides the paraffinsulphonic acids, a considerable amount of H2SO4. In order to remove said sulphuric acid, according to the process of the present invention, 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 H2O and H2SO4, 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.
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