Patent GB-436357-A (GB)
Title: Process for the treatment of unsaturated polyhalides
IPC: C07C29/66
Filed: 1935-04-15
Abstract: Unsaturated polyhalides are reacted with hypohalogenous acids, aqueous halogen solutions, solutions of hypohalogenous acids and hydrogen halides, or alkyl or aralkyl hypohalites in the presence of water, to give polyhalogenated hydroxy compounds or hydrocarbons, or both.  The unsaturated polyhalides may be of the vinyl type, containing at least one olefinic linkage embracing two vicinal unsaturated carbon atoms to which at least two halogen atoms are attached, or of the allyl type with at least two halogen atoms neither of which is attached to either of the vicinal carbon atoms embraced in the olefinic linkage.  Such linkage is included in an iso or normal alkyl chain which may be attached to a cyclic radical or may comprise an alicyclic structure.  Hypohalogenous acids may be prepared by dissolving halogen in water in presence of weakly basic substances such as sodium bicarbonate, mercuric oxide or calcium carbonate, by electrolysis of metal or hydrogen halides, by reaction of metal hypohalites with dilute acids, or decomposition of organic hypohalites with water.  To prevent side reactions contact of the unsaturated polyhalide with undissolved halogen is avoided, for example by preparing the halogen solution in a separate stage as by absorption of gaseous or liquid chlorine or bromine in a concurrent or countercurrent absorption system. The concentration of hydrogen halide in the reaction system should not exceed 1.5 normal, the optimum concentration varying with the organic halide and the halogen halide employed.  The concentration of hypochlorous acid is generally kept below 0.1 normal, the optimum being between 0.005 and 0.015 N. Hypobromous and hypoiodous acids may be present in higher concentrations. The concentration may be varied to control the relative amounts of useful products formed.  The polyhalides employed may be gaseous, liquid or solid, but the reaction is usually effected in the liquid phase.  Organic substances such as alcohols, ethers, esters, hydrocarbons, or halogenated hydrocarbons, which may or may not be inert, can be added.  Primary, secondary or tertiary alkyl or aralkyl esters of hypochlorous or hypobromous acid, or mixtures thereof are the most suitable organic hypohalites for the present process.  The reaction is illustrated by the following: CH2=CH--CHCl2 +(CH3)3 COCl + H2O --> CH2Cl - CHOH - CHCl2 + (CH3)3 COH.  The products may be used as solvents or intermediates, or separated and the alcohols used to prepare hypohalites.  Room temperature is generally employed although higher temperatures may be used, while in some cases it is preferably to operate substantially below 20 DEG  C. Pressure is usually atmospheric but may be greater or less. According to examples: (1) A cyclic system comprising reaction chamber, a separator stage for breaking up emulsions in the reaction products, and an absorption column for saturating circulating water with chlorine is employed.  The apparatus is charged with water, carbon tetrachloride, and 1.4 dichlor-2(chlor-methyl) butene-2 of the formula <FORM:0436357/IV/1> These are agitated in the reaction chamber and the water circulated through the system, chlorine being introduced continuously into the absorption column.  The unsaturated halide is intermittently admitted to the reaction chamber.  Water is introduced to keep the HCl content of the circulating solution at or below 1.13 N.  Portions of both liquid phases in the reaction chamber are withdrawn when necessary to maintain the volume in the system substantially constant.  The product separates into two layers and the lower, together with an ether extract of the other is dried and distilled to remove the bulk of the ether and carbon tetrachloride. The product is distilled at reduced pressure and is a tetrachlor tertiary amyl alcohol, probably <FORM:0436357/IV/2> (2) <FORM:0436357/IV/3> and water are stirred together, tertiarybutylhypochlorite being added periodically.  The products are tertiary butyl alcohol and a trichlor tertiary butyl alcohol, probably <FORM:0436357/IV/4> (3) Hypochlorous acid solution is added to a mixture of water and <FORM:0436357/IV/5> to yield <FORM:0436357/IV/6> (4) CHCl = CCl2 is treated as in (1) to give CHCl2--CCl3.  (5) Chlorine is introduced into a mixture of water and dichlor-di-isobutylene, probably <FORM:0436357/IV/7> The product has the formula C8H13Cl3.  (6) Ice-cold 0.1 N HOBr is added to a suspension of <FORM:0436357/IV/8> in ice water.  The product is <FORM:0436357/IV/9> Products of the present process may be used as solvents and extractants, e.g. in the refining of mineral oils and purification of refinery and manufactured gases.  The polyhalogenated alcohols may be hydrolyzed to polyhydric alcohols.  Specification 402,880 is referred to.ALSO:Polyhalogenated hydroxy compounds or hydrocarbons, prepared by the reaction of an unsaturated polyhalide with hypohalogenous acids, aqueous halogen solutions, solutions of hypohalogenous acids and hydrogen halides, or alkyl or aralkyl hypohalites in the presence of water, are used as solvents and extractants in the refining of mineral oils.  Products specified are 1.3.3.trichlor-propanol-2, a tetrachlor-tertiary amyl alcohol, a trichlor-tertiary butyl alcohol, 1.6-dichlor-2.5(chlormethyl)-hexanediol-2.5, pentachlorethane, C8H13Cl3, and a dichlor-monobrom-tertiary butyl alcohol. Hypohalogenous acids may be prepared by dissolving the halogen in water in the presence of weakly basic substances such as sodium bicarbonate, mercuric oxide, or calcium carbonate, by electrolysis of metal halides and hydrogen halides, or by the decomposition of metal hypohalites with dilute acids or of organic hypohalites with water. Gaseous or liquid chlorine or bromine may be absorbed in water in a concurrent or countercurrent system.