| 摘要 |
1,137,273. Process for preparation of methyl vinyl ether. IMPERIAL CHEMICAL INDUSTRIES Ltd. 1 Aug., 1966 [18 Aug., 1965], No. 35366/65. Heading C2C. Methyl vinyl ether is separated from a mixture containing methyl vinyl ether and acetaldehyde by continuously distilling the mixture in a fractionating column into which a lower aliphatic alcohol of 1 to 4 carbon atoms, suitably methanol, is fed at a point higher in the column than the feed point of the mixture, and taking off an overhead product comprising a higher proportion of methyl vinyl ether to acetaldehyde than was present in the mixture. This process may form part of a continuous production process for methyl vinyl ether by condensing methanol with acetaldehyde, separating a product comprising dimethyl acetal, unchanged methanol and acetaldehyde from water produced in the condensation, passing this product over an acetal cracking catalyst at an elevated temperature, separating methyl vinyl ether from the ensuing mixture of methyl vinyl ether, unchanged dimethyl acetal, methanol and acetaldehyde by the method indicated above, taking off the distillate overhead, and recycling a residue of dimethyl acetal, methanol and acetaldehyde taken from the bottom of the column. Preferably, all the methanol required for the condensation is introduced via the fractionating column; methanol and acetaldehyde are condensed together in the liquid phase at a temperature between 0‹ and 50‹ C. with an acid substance as a catalyst; the product of the condensation is passed over a catalyst, comprising barium oxide deposited on silica gel, at a temperature between 20‹ and 450‹ C.; the mole rate of addition of the lower aliphatic alcohol is greater than the mole rate of addition of acetaldehyde to the column; pressures between 5 and 10 atmospheres are used in the distillation; and the temperature at the base of the column is maintained at about the boiling point of methanol. |
