Patent GB-630248-A (GB)
Title: Improvements in or relating to dehydrohalogenated derivatives and process of producing the same
IPC: C07C1/30
Filed: 1946-01-25
Abstract: Organic compounds are dehydrohalogenated by reaction with a hydrogen halide sequestering material in a mutual liquid solvent comprising a polyhydric alcohol, an ether alcohol or an amine alcohol, at a reaction temperature above the boiling point of the dehydrogenated derivative and below the boiling point of the solvent and which is between 70 DEG  and 350 DEG  C.  A mutual liquid solvent is defined as a solvent capable of dissolving the sequestering material <PICT:0630248/IV (b)/1> and some of the halogenated organic compound, but not substantial amounts of organic reaction product; and having a boiling point above that of water but below 350 DEG  C.  It should boil from 30-80 DEG  C. or more higher than the reaction product. Organic compounds specified include mono- and poly-halides of alkenes, and alkanes, halogenated alcohols, acids, ketones, ethers, esters, amines, amides, and naphthenes, and aromatic compounds with halogenated side-chains.  Bromides, iodides, and fluorides, as well as chlorides may be used.  They are divided into two groups: (1) those whose dehydrohalogenated derivatives boil below 100 DEG  C., e.g. ethylene dichloride, and (2) those whose derivatives boil between 100 DEG  and 350 DEG  C., e.g. chlormethylcyclohexane. Sequestering materials comprise bases soluble to some extent in the solvent medium, e.g. sodium and potassium hydroxide.  Mutual solvents include mono- and poly-ethylene, propylene, and butylene glycols, dihydroxy propanes and butanes, b -ethoxy-butyl alcohol, b -phenoxyethyl alcohol or its 2-chlor derivative, 4-tertiary butyl-b -phenoxy-ethyl alcohol, mono-, di- and tri-ethanolamines. Apparatus for continuous treatment of Group (1) compounds comprises a reactor 1 with steam heaters 2 and communicating with tanks 4, 5, 6 of caustic soda, glycol, and ethylene dichloride respectively.  Reaction is effected at about 120 DEG  C.  Sodium chloride is withdrawn into separator 8, glycol and ethylene dichloride being returned through pipe 9.  Vinyl chloride passes through pipe 13, water and ethylene dichloride being condensed in 14 and separated in 20, and is compressed into tank 18 from which it may be fed to fractionator 19. For Group (2) compounds, the apparatus, Fig. 2 (not shown), comprises a condenser wherein all the vapours are condensed, water separated, and the remaining mixture such as cyclohexene and chlorcyclohexane fractionated to recover the former, the latter being recycled. Examples describe the preparation of vinyl chloride and bromide from ethylene dichloride and dibromide, 1,1-dichlorethylene from 1,1,2-trichlorethane, 1-chlorpropene-1 from 1,2-dichlorpropane, cyclohexene from chlorcyclohexane, and methylcyclohexenes from monochlormethylcyclohexane, by reaction with caustic soda in ethylene or diethylene glycol.  The preparation of methyl vinyl ketone from a -chlormethyl ethyl ketone, di-vinyl ether from b ,b 1 - dichlor ethyl ether, ethylene oxide from ethylene chlorhydrin, acrylic acid from b -chlor propionic acid, and olefins from chlorinated gasoline is also specified.  Specificatio 569,291 is referred to.  The Specification as open to inspection under Sect. 91 comprises the treatment of a third group of organic compounds whose reaction products decompose before boiling or are not volatilizable, e.g. chlorinated paraffin waxes.  It includes additional examples of ether alcohols used as mutual solvents.  This subject-matter does not appear in the Specification as accepted.