Patent GB-384654-A (GB)
Title: Improvements in and relating to acetylene reactions
IPC: C07C17/08
Filed: 1931-05-27
Abstract: <PICT:0384654/IV/1> Non-benzenoid acetylene polymers, particularly monovinylacetylene, divinylacetylene, and an acetylene tetramer C8H8, are obtained by subjecting acetylene to the action of an acid catalyst mixture comprising a cuprous salt and a salt of ammonium or of a tertiary amine.  Vinyl chloride is obtained if the reaction mixture includes hydrochloric acid.  The catalyst preferably comprises a saturated aqueous solution of the said salts of pH6 or less, some undissolved salt being present to ensure saturation. Copper may also be present, to prevent oxidation of the cuprous salt, or the latter may be formed in situ from copper and a cupric salt.  A sufficient acidity in the solution may be attained merely by hydrolysis.  The salts may also be used in association with a solution of sodium or potassium chloride, or in suspension in an inert liquid such as benzene or chlorobenzene.  The catalyst may comprise, on the one hand, cuprous chloride, bromide, iodide or cyanide, or cupric sulphate and copper, and on the other hand an ammonium halide, ammonium sulphate or acetate, pyridine hydrochloride, formate, or acetate, quinaldine hydrochloride, or tributylamine hydrochloride.  In examples, (1) acetylene is passed at atmospheric or raised pressure into an agitated mixture of ammonium chloride, cuprous chloride, copper powder and water; the temperature is preferably kept at about 25 DEG  C., and when the absorption of acetylene slackens the mixture is distilled, yielding the acetylene polymers specified above; (2) acetylene is passed at atmospheric or raised pressure into a mixture of aqueous hydrochloric acid, ammonium chloride, cuprous chloride and copper powder, preferably at 20-40 DEG C., and the mixture is afterwards heated, yielding vinyl chloride; alternatively, acetylene may be absorbed in an aqueous cuprous chloride-ammonium chloride mixture, and hydrogen chloride afterwards passed in under pressure.  Apparatus for conducting the process continuously comprises a tube 1 fitted with an agitator 2 and immersed in an electrically heated bath 3.  The catalyst is introduced into the tube 1, and acetylene is passed in through a pipe 5 and blower 6.  The reaction products pass to a condenser 9 and thence to a separator 13, from which uncondensed gases are returned to the tube 1 through a pipe 14.  The aqueous portion of the condensate is returned to the tube 1 through a pipe 15, and the remaining reaction products flow to a container 17. The operation of the apparatus is described in a further example (example 3) in which the acetylene polymers specified above are prepared with the aid of the catalyst specified in example (1); the polymers may be separated from one another by distillation, preferably under reduced pressure. The catalyst may become contaminated after a time with tarry and resinous byeproducts. To recover copper from the spent catalyst, the latter is chlorinated to give a solution containing copper chloride. The solution may then be divided into two parts, one of which is treated with zinc or iron to precipitate copper, the precipitate being added to the other part so as to produce a mixture of cuprous chloride and copper suitable for re-use.  Alternatively, the whole of the copper may be precipitated.  Examples (4) and (5) give details of these alternative processes.  The tar and resins removed by decantation or filtration from the chloride solution may be burnt, and the copper in the ash leached out with acid.ALSO:<PICT:0384654/III/1> Non-benzenoid acetylene polymers, particularly monovinylacetylene, divinylacetylene, and an acetylene tetramer C8 H8, are obtained by subjecting acetylene to the action of an acid catalyst mixture comprising a cuprous salt and a salt of ammonium or of a tertiary amine.  The catalyst preferably comprises a saturated aqueous solution of the said salts of pH 6 or less, some undissolved salt being present to ensure saturation. Copper may also be present, to prevent oxidation of the cuprous salt, or the latter may be formed in situ from copper and a cupric salt.  A sufficient acidity in the solution may be attained merely by hydrolysis.  The salts may also be used in association with a solution of sodium or potassium chloride, or in suspension in an inert liquid such as benzene or chlorobenzene.  The catalyst may comprise, on the one hand, cuprous chloride, bromide, iodide or cyanide, or cupric sulphate and copper, and on the other hand an ammonium halide, ammonium sulphate or acetate, pyridine hydrochloride, formate, or acetate, quinaldine hydrochloride, or tributylamine hydrochloride. Apparatus for conducting the process continuously comprises a tube 1 fitted with an agitator 2 and immersed in an electrically heated bath 3.  The catalyst is introduced into the tube 1, and acetylene is passed in through a pipe 5 and blower 6.  The reaction products pass to a condenser 9 and thence to a separator 13, from which uncondensed gases are returned to the tube 1 through a pipe 14.  The aqueous portion of the condensate is returned to the tube 1 through a pipe 15, and the remaining reaction products flow to a container 17.  The catalyst may become contaminated after a time with tarry and resinous bye-products.  To recover copper from the spent catalyst, the latter is chlorinated to give a solution containing copper chloride.  The solution may then be divided into two parts, one of which is treated with zinc or iron to precipitate copper, the precipitate being added to the other part so as to produce a mixture of cuprous chloride and copper suitable for re-use. Alternatively, the whole of the copper may be precipitated. Examples are given of these alternative processes.  The tar and resins removed by decantation or filtration from the chloride solution may be burnt, and the copper in the ash leached out with acid.