| 摘要 |
A process for preparing chloral alcoholate or free chloral comprises contacting ethyl alcohol at a temperature not exceeding 35 DEG C. with part of the chlorine required, and subsequently treating the heated reaction liquid obtained continuously in countercurrent with the rest of the chlorine required, whereby a prolonged contact between the hydrogen chloride formed and the unconverted ethyl alcohol, sufficient for the formation of substantial proportions of ethyl chloride is prevented. The cold chlorination may be carried out batchwise or in counter-current. The chlorine supply may be adjusted in the hot process to produce chloral alcoholate or free chloral. Pressure may be normal or otherwise, e.g. hydrogen chloride is more easily removed from the hot reaction zone by operating at reduced pressure. A chlorination catalyst <PICT:0644916/IV (b)/1> may be present, e.g. ferric chloride. In examples: (1) 96 per cent ethyl alcohol containing ferric chloride is passed into vessel 1 maintained at room temperature via tube 2 whilst chlorine is passed in through tube 3. The reaction mixture is then passed through tube 5 into the top of heated reactor 6, further chlorine being led in at the bottom via tube 10. Hydrogen chloride escapes through the reflux condenser 7 and the reaction product collects in vessel 8. Pure chloral is obtained from the latter by fractional distillation. Residual alcohol is collected in scrubber 12. (2) A similar chlorination is carried out using a third reactor operating at an intermediate temperature between the hot and cold reactions, both free chloral and the alcoholate being obtained. The Specification as open to inspection under Sect. 91 comprises also the production of dichloroacetaldehyde and acetals of di- and trichloroacetaldehyde. This subject-matter does not appear in the Specification as accepted. |
