| 摘要 |
Hydrocarbon motor spirit, especially that produced by cracking or low-temperature carbonization, is purified and stabilized by treatment successively with alkali, sulphuric acid, and alkali, in which: (1) the first alkali treatment is effected before prolonged storage, preferably before or during condensation; (2) such a proportion of about 95-96 per cent acid is used as to remove only the basic and the more unsaturated compounds such as diolefines; (3) the acid-treated spirit is allowed to stand for a prolonged time before neutralization and the second alkali treatment is carried out for a prolonged time. Fractional distillation may follow. The first alkali treatment may be in two stages, e.g. first by flowing the spirit continuously upwards through an aqueous suspension of lime to remove sulphur and easily decomposed compounds, and then circulating with caustic soda through a pump to remove phenols. The acid wash may also be in two stages, e.g. first by agitation for 10 min. with 1-1,5 per cent by vol. of acid tar from the second stage followed by settling for 30 min. and then with 0,5 per cent by vol. of 95-96 per cent acid for 30-45 min. followed by settling for 3-3,5 hr. The acid tar produced is preserved from oxidation in a closed vessel until required. The neutralization is preferably effected by soda ash solution. |
