Patent GB-473219-A (GB)
Title: Improvements in and relating to the production of polymerisation products from acetylene
IPC: C07C2/48
Filed: 1936-09-17
Abstract: Aromatic hydrocarbons and monovinylacetylene are produced simultaneously by passing acetylene at 300--800 DEG  C. over a catalyst comprising (a) gold, molybdenum or silver, or their alloys, or (b) alloys containing iron, aluminium, silicon and chromium, or (c) carbon obtained by thermal decomposition of acetylene, or (d) an oxide of titanium, uranium or zirconium.  The reaction may be effected at atmospheric or slightly raised pressure, and the acetylene may be mixed with other gases, such as nitrogen, carbon dioxide, methane or hydrogen.  The catalysts may be supported on porous material such as porous porcelain, carbon (other than catalytic carbon, as defined above), silica gel, pumice or asbestos. To restrain undesired reactions, such parts of the apparatus as come into contact with acetylene are preferably made of or lined with (a) steel containing carbon 0,1--0,2, nickel 18--26, and chromium 20--30 per cent, such as one of the steels known commercially as "NCT steels," or (b) p  steel containing carbon 0,01--0,05, aluminium up to 3, silicon 1, and chromium 4--24 per cent, with or without small proportions (less than one per cent) of molybdenum and/or vanadium, such as a steel sold under the Registered Trade Mark "Sicromal"; for such parts of the apparatus as are not exposed to temperatures above 450 DEG  C. aluminium or an alloy thereof, e.g. "anticorodal," may be used, or in place of any of the specified materials use may be made of acid or neutral refractory materials or enamels.  The reaction products may be separated by fractional condensation, or partly by condensation and partly by absorption in liquid or solid absorbents; specified absorbents are kieselguhr, fuller's earth, active carbon, bone black, tetra- or deca-hydronaphthalene, mineral oils, and mixtures of alcohols containing more than four carbon atoms; any unpolymerized acetylene may be recirculated through the apparatus. In the examples: (1) acetylene is led at 680 DEG  C. through a tube made of NCT steel packed with rolls of wire mesh made from an iron-aluminium-silicon-chromium alloy containing aluminium 2,5, silicon 0,8 and chromium 20 per cent; the products are cooled to atmospheric temperature, and the uncondensed residue is led over active carbon; the portion condensed at atmospheric temperature is fractionated; the portion absorbed by the active carbon is also fractionated, and yields a fraction of high monovinylacetylene content; other specified products are cyclopentadiene, benzene, toluene, styrene, indene, hydrindene, naphthalene, methylnaphthalene, fluorene, phenanthrene and anthracene; (2) acetylene is led at 620 DEG  C. over a catalyst prepared by impregnating pumice with silver nitrate solution and reducing the salt to metallic silver by means of formic acid; the reaction products are treated as in example 1, and yield similar fractions.ALSO:Mixtures of acetylene with monovinylacetylene are separated by p  absorption in liquid or solid absorbents; specified absorbents are kieselguhr, fuller's earth, active carbon, bone black, tetra- or deca-hydronaphthalene, mineral oils, and mixtures of alcohols containing more than four carbon atoms.ALSO:As materials for making or lining apparatus for the thermal treatment of acetylene, reference is made to (a) steel containing carbon 0,1-0,2, nickel 18-26, and chromium 20-30 per cent, such as one of the steels known commercially as "NCT steels." and (b), steel containing carbon 0,01-0,05, aluminium up to 3, silicon 1, and chromium 4-24 per cent, with or without small proportions (less than one per cent) of molybdenum and/or vanadium, such as a steel sold under the Registered Trade Mark "Sicromal."  As a catalyst for use in the process, an iron-aluminium-silicon-chromium alloy containing aluminium 2,5, silicon 0,8, and chromium 20 per cent is specified.