| 摘要 |
Sulphuric acid is concentrated to about 82 per cent strength in ordinary lead apparatus, and further concentration is then effected in vessels of lead alloyed with a little copper.ALSO:In the successive absorption of propylene and ethylene from gases containing them, absorption of propylene in an acid is followed by absorption of ethylene in the same acid at a lower concentration. Absorption of propylene may be effected in sulphuric acid of 80--90 per cent strength at atmospheric or raised temperature and pressure, but preferably in 87 per cent sulphuric acid at 20--23 DEG C. and 10--25 atm. pressure; absorption of ethylene may then be effected in 75--85 per cent, sulphuric acid, preferably at 90--130 DEG C. and 10--25 atm. pressure. Each absorption may be promoted by the presence of a catalyst, e.g. silver oxide, ferrous ammonium sulphate, mercurous sulphate, or sulphate of silver, calcium, lead, iron or copper, and instead of sulphuric acid other acids such as phosphoric acids or strong sulphonic acids may be used. The gases treated may be cracking gases, which may be generated under the same pressure as that applied during the absorption, and may be preliminarily enriched in olefines, as by liquefaction, and (or) treated to remove olefines higher than propylene, as by scrubbing the gases with 60--65 per cent sulphuric acid at 90--110 DEG C. or with 80 per cent sulphuric acid at 0--15 DEG C. The absorption products may be worked up to alcohols and (or) ethers by dilution (if necessary) followed by distillation; dilution may be effected with water or with the alcohol or aqueous alcohol corresponding to the olefine absorbed; the subsequent distillation is preferably effected below 120 DEG C. and if desired under reduced pressure or in a stream of inert gas. After the distillation, the residual acid may be concentrated for re-use; concentration of sulphuric acid to about 82 per cent strength may be effected in ordinary lead apparatus, and further concentration in vessels of lead alloyed with a little copper. Specification 401,269 is referred to.
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