Patent GB-401678-A (GB)
Title: Improvements in methods of forming non-benzenoid hydrocarbons from acetylene
IPC: C07C2/38
Filed: 1932-05-11
Abstract: <PICT:0401678/III/1> The processes described in the parent Specification and in Specification 390,179, according to which nonbenzenoid acetylene polymers such as mono- and divinylacetylene are obtained by treating acetylene with an acid catalyst mixture comprising a cuprous salt and a salt of ammonia or of a tertiary amine, with or without an acid, are modified by removing monovinylacetylene from the reaction mixture before substantial amounts of divinylacetylene are formed, so that a product consistting mainly of monovinylacetylene is obtained.  Preferably, the continuous process described in the parent Specification is modified by circulating the acetylene through the reaction vessel and associated apparatus at a higher rate than that recommended in the parent Specification.  In this modification, the mixture of acetylene and monovinylacetylene leaving the reaction vessel is first cooled to about 0 DEG  C. to separate water and any divinylacetylene or higher acetylene polymers that may have been formed.  Monovinylacetylene may then be separated by absorption in a solid or liquid absorbent, reference being made in this connection to boneblack, fuller's earth, kieselguhr, active charcoal, silica or alumina, furfural, mineral oil, tetralin, decalin, glycerol, glycol and other higher alcohols, and ditolyethanes.  The plant shown comprises an acetylene supply vessel 1, a blower 3, preheater 5, reaction vessel 7, a preliminary condenser 9 cooled to about 0 DEG  C., a conduit 19 for the return of condensed water to the vessel 7, condensers 12, 12<1> cooled to about -60 DEG  C., conduits 16, 17 for the return of acetylene and water respectively to the vessel 7, a still 13 in which the condensed monovinylacetylene is freed from dissolved acetylene, and a storage tank 14 for the final product.  In the examples, details are given of the continuous production of monovinylacetylene as described above, the catalyst consisting of an aqueous mixture of ammonium chloride, cuprous chloride, copper powder, and hydrochloric acid.  The catalyst may also comprise on the one hand, cuprous bromide, iodide, or cyanide, and on the other hand ammonium bromide, iodide, fluoride, sulphate, or acetate, pyridine hydrochloride, formate, or acetate, quinaldine hydrochloride, or tributylamine hydrochloride, with or without an inorganic or organic acid, as described in Specification 390,179.ALSO:<PICT:0401678/IV/1> The processes described in the parent Specification and in Specification 390,179, according to which non-benzenoid acetylene polymers such as mono and di-vinylacetylene are obtained by treating acetylene with an acid catalyst mixture comprising a cuprous salt and a salt of ammonia or of a tertiary amine, with or without an acid, are modified by removing monovinylacetylene from the reaction mixture before substantial amounts of divinylacetylene are formed, so that a product consisting mainly of monovinylacetylene is obtained.  Preferably, the continuous process described in the parent Specification is modified by circulating the acetylene through the reaction vessel and associated apparatus at a higher rate than that recommended in the parent Specification.  In this modification, the mixture of acetylene and monovinylacetylene leaving the reaction vessel is first cooled to about 0 DEG  C. to separate water and any divinylacetylene or higher acetylene polymers that may have been formed.  Monovinylacetylene is then separated by condensation at about -50 to -60 DEG  C. at atmospheric or raised pressure, and.or by absorption.  Solid or liquid absorbents may be used, reference being made in this connection to boneblack, fuller's earth, kieselguhr, active charcoal, silica or alumina, furfural, mineral oil, tetralin, decalin, glycerol, glycol and other higher alcohols, and ditolylethanes Unchanged acetylene, preheated if necessary, is returned to the reaction vessel together with fresh acetylene and water or acid required to maintain the concentration of the catalyst mixture.  The plant shown comprises an acetylene supply vessel 1, a blower 3, preheater 5, reaction vessel 7, a preliminary condenser 9 cooled to about 0 DEG  C., a conduit 19 for the return of condensed water to the vessel 7, condensers 12, 12<1> cooled to about -60 DEG  C., conduits 16, 17 for the return of acetylene and water respectively to the vessel 7, a still 13 in which the condensed monovinylacetylene is freed from dissolved acetylene, and a storage tank 14 for the final product.  In the examples, details are given of the continuous production of monovinylacetylene as described above, the catalyst consisting of an aqueous mixture of ammonium chloride, cuprous chloride, copper powder, and hydrochloric acid.  The catalyst may also comprise, on the one hand, cuprous bromide, iodide, or cyanide, and on the other hand ammonium bromide, iodide, fluoride, sulphate, or acetate, pyridine hydrochloride, formate, or acetate, quinaldine hydrochloride, or tributylamine hydrochloride, with or without an inorganic or organic acid, as described in Specification 390,179.  An alternative method of carrying out the invention comprises charging acetylene into a vessel containing a catalyst of the kind described above, and distilling the product within eight hours through a condenser held at -40 to -70 DEG  C.