Patent GB-836897-A (GB)
Title: Process for carrying out telomerisation reactions
IPC: C07C17/275
Filed: 1957-01-14
Abstract: In a continuous process for the preparation of telomers of olefines such as ethylene, propylene, hexene, octene or styrene by reacting with telogens such as halogenated aliphatic hydrocarbons, e.g. carbon tetrachloride and chloroform, or halogen derivatives of cyanogen, e.g. cyanogen chloride, or aldehydes, in the presence of free-radical forming catalysts, the unreacted gaseous olefine and the gaseous telogen are constantly removed from the reaction chamber, the olefine is liquefied by cooling and recycled together with unreacted telogen and fresh olefine, or telogen, while the unreacted polymer is constantly removed.  Elevated temperatures and pressures, e.g. up to 250 DEG  C., and between 20 and 1000 atmospheres, respectively, may be used and the circulating olefine is cooled in stages, in the first of which the liquified telogen is separated and returned to the reaction chamber and in the second the olefine is liquefied and any free hydrohalic acid may be absorbed, for example by calcium oxide. In an example a mixture comprising after vacuum rectification 4.5% b -chloropropionic acid nitrile, 25.5% d -chloro-n-valeronitrile, 21.6% w-chloro-n-enanthic acid nitrile, 12.4% w-chloro-n-pelargonic acid nitrile, 12.6% w-chloro-n-undecanic acid nitrile and 23.4% higher nitriles is prepared from cyanogen chloride and ethylene in the presence of azobutyric acid nitrile. Specification 836,896 is referred to.ALSO:<PICT:0836897/IV (a)/1> In a continuous process for the preparation of telomers of olefines such as ethylene, propylene, hexene, octene or styrene by reacting with telogens such as halogenated aliphatic hydrocarbons, e.g. carbon tetrachloride and chloroform, or halogen derivatives of cyanogen, e.g. cyanogen chloride, or aldehydes, in the presence of free-radical forming catalysts the unreacted gaseous olefine and the gaseous telogen, are constantly removed from the reaction chamber, the olefine is liquefied by cooling and recycled together with unreacted telogen and fresh olefine or telogen, while the unreacted polymer is constantly removed.  Elevated temperatures and pressures e.g. up to 250 DEG  C., and between 20 and 1000 atmospheres respectively, may be used and the circulating olefine is cooled in stages, in the first of which the liquefied telogen is separated and returned to the reaction chamber and in the second the olefine is liquefied and any free hydrohalic acid may be absorbed, for example by calcium oxide.  In an example, a mixture of cyanogen chloride and azobutyric acid nitrile is sprayed at nozzle D, into ethylene under 150 atmospheres pressure and at 160 DEG  C. in a reaction tube (1) and the resulting chloronitrile collected in sump (2) maintained at 120 DEG  C. and at constant level.  The expansion chamber (4) receives the reaction product and the liquid products are pumped to a continuous distillation column (6) to separate the cyanogen chloride and chloronitrile while the telomer is condensed at 8.  The cyanogen chloride is passed through hydrochloric acid absorption columns 9, a condenser 10 and recirculated together with catalyst from reservoir 14 to the nozzle D.  Gaseous ethylene and cyanogen chloride from 4 are passed to compressors 16 and separators I to IV and the ethylene returned to the reaction system.  The cyanogen chloride is separated from the ethylene from the gas chamber of sump 2 in the chamber 18 containing Raschig rings and returned to the sump.  The ethylene is freed from hydrogen chloride, condensed 22 and 23 and returned from pressure receiver 24 to nozzle D.  The telomers are vacuum rectified to yield 4.5% b -chloropropionic acid nitrile, 25.5% d -chloro - n - valeronitrile, 21.6% o  - chloro - n - enanthic acid nitrile, 12.4% o -chloro-n-pelergonic acid nitrile, 12.6% o -chloro-n-undecanic acid nitrile, and 23.4% higher nitriles.  Specification 836,896 is referred to.