Patent GB-591799-A (GB)
Title: Improvements in chlorination of hydrocarbons
IPC: C07C19/10
Filed: 1944-12-13
Abstract: In a process for the chlorination of hydrocarbons (see Group IV) in which a salt melt comprising cuprous chloride and potassium chloride is first contacted with an oxygen containing gas and dry hydrogen chloride at a temperature of 250 DEG C. to 475 DEG C. to form cupric chloride from the cuprous chloride and the cupric chloride melt then contracted with the hydrocarbon in a second zone, a double salt which corresponds to the formula K2 Cu Cl4 is stated to be formed between the copper and potassium chlorides.ALSO:<PICT:0591799/IV/1> Organic chlorides are prepared by passing an oxygen containing gas and dry hydrogen chloride in contact with a salt melt comprising cuprous chloride at a temperature of 250 DEG  C. to 475 DEG  C. to form cupric chloride, and then in a separate stage contacting the cupric chloride melt with a hydrocarbon in the gaseous state, at a temperature of 325 DEG  C. to 500 DEG  C. to reform cuprous chloride, and recovering the organic chloride formed.  In the apparatus shown, a melt comprising a mixture of cuprous chloride and potassium chloride is introduced into the top of packed tower 1 through line 2. Air is admitted through lines 4 and 5 and may be under pressure and dry hydrogen chloride through line 8.  the melt containing cupric chloride leaves through line 11.  It may be subjected to the purging action of hydrogen chloride or an inert gas such as nitrogen just prior to leaving.  It is passed into tower 17 through the lines 14 and 16, the latter stream being preheated, and flows down the tower while the preheated hydrocarbon vapour is passed in through line 18. The reaction in this tower may be carried out under pressure. Hydrocarbon chloride and hydrogen chloride pass out of line 20 and the latter may be returned to tower 1.  To increase conversion, part of the product stream in line 20 may be recycled through tower 17. The used melt is returned to the top of tower 1 for recycling through the process.  The oxychlorination of cuprous chloride to cupric chloride may also be effected in two separate stages whereby the cuprous chloride is first converted to oxychloride by air and then the latter is converted to cupric chloride in a second step by hydrogen chloride introduced at the bottom of the tower.  Instead of passing the melt in countercurrent to the gas flowed over a contact mass, the gases may be bubbled into the body of the melt. In the examples a cuprous chloride potassium chloride salt melt is used through which is bubbled first air and then hydrogen chloride or a mixture of air and hydrogen chloride.  Methane and ethane, respectively, are bubbled through the cupric chloride melt so formed yielding respectively methyl chloride with some methylene chloride, chloroform and carbon tetrachloride; and ethyl chloride mixed with other chlorides of ethane and ethylene, together with a p  small amount of ethylene.  Other chlorides which may be mixed with the copper chlorides to form melts are alkali metal chlorides. Chlorides of metals in Groups I, II, III and IV of the Periodic Table having atomic weights greater than copper, such as lead, zinc, silver and thallium may be used in place of or together with the alkali metal chlorides.  Other hydrocarbons which may be chlorinated are stated to be those which are gaseous at temperatures less than 400 DEG  C. such as propane, benzene, toluene, cyclopropane, cyclobutane, ethylene and propylene.  In the case of butane the reaction product will contain in addition to the primary chloride, dichlorides, unsaturated chlorides and olefines.  The Specification as open to inspection under Sect. 91 refers to the production of organic halides generally and to the use of copper halide melts.  It is also not restricted to the use of dry hydrogen chloride and the employment of melts only and states that solids such as pumice, impregnated with copper halides may be circulated through the process.  The temperature in the first reaction zone is stated to be 200 DEG  C. to 475 DEG  C. and the temperature in the second zone to be above 325 DEG  C. and the Specification is not restricted to hydrocarbons in the gaseous state. This subject-matter does not appear in the Specification as accepted.