| 摘要 |
Ethers are prepared by contacting one or more olefines with a strong acid catalyst in the presence of a halogenated aromatic hydrocarbon which contains no further substituent or one or more alkyl, sulphonic, methoxy or phenyl groups, and in the presence of and/or with the subsequent addition of water. It is preferred to carry out the process in the presence of an ether-selective solvent with the halogenated hydrocarbon as cosolvent. When the catalyst used is sulphuric acid, preferably of 65-70% by weight concentration the reaction temperature is preferably 190-250 DEG F. When the catalyst is a resin such as a polystyrene sulphonic acid or a sulphonated co-polymer of styrene and divinylbenzene temperatures in the range 250-350 DEG F are preferred. Preferred olefines for use as starting materials are those having 2-4 carbon atoms and with these the pressure is desirably in the range 500-3000 p.s.i. Suitable cosolvents which may be used are halogenated benzenes, naphthalenes and 1.2.3.4-tetrahydronaphthalenes. Solvents which may be used with the halogenated hydrocarbons are benzenes, naphthalenes, naphthenic hydrocarbons, aliphatic hydrocarbons and ethers. When ethylene is used as starting olefine it is preferred to use p-chlorobenzene sulphonic acid as co-solvent. Examples are given of the conversion of propylene to diisopropyl ether. Some propyl alcohol is also formed and this may be recycled.
|
