SO3 utilization efficiency

Photolysis of alkane/S02 mixtures leads to the formation of alkylsulfonic acids,the Hostapon process utilizing SOdOilhvP It is curious that this reaction seems to be so efficient, given the low e for alkane and SO2 at the wavelengths used, and an efficient chain reaction is presumably involved. The Reed reaction uses SO2/CI2/I11 to convert alkanes to the corresponding sulfonyl chlorides. Alkanes also react with SO3 to give alkyl sulfonates, sulfones and sulfates. ... 

This is confirmed, for instance, when the obtainable product quality, energy and utilities demand, and raw material consumption for LAS production are comparatively taken into account for oleum-and SOj-based processes, as shown in Table 5.8. For the oleum-based sulfonation plant, the spent acid represents an important variable (either for its neutralization or simple disposal for further SOj recovery) with heavy impact on the process cost. Moreover, the availability and cost of oleum derived from local situation that, case by case, might contribute to make this sulfonating agent comparatively cheaper than the more modern, clean, efficient, and versatile gaseous SO3. 

Any other process currently in practice requires higher utility costs. As regards raw material, equivalent sulphur required is 40 % of 0.841 = 0.3364 plus 0.175 i.e. 0.511. Part of purged SO2/SO3 is returned to Sulphuric acid plant. Hence, Sulphur efficiency is higher than 98 percent. 

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