Patent GB-713854-A (GB)
Title: Improvements in the production of primary halohydrocarbons
IPC: C07C17/272
Filed: 1951-10-12
Abstract: Primary halohydrocarbons are obtained by reacting together a tertiary-unsaturated olefinic hydrocarbon, ethylene, and a hydrogen halide, in the presence of a catalyst of the Friedel-Crafts type. The tertiary olefinic hydrocarbon is defined as one having the general formula: <FORM:0713854/IV (b)/1> wherein of the symbols R1, R2, R3 and R4 either R3 or R4 or both may represent hydrogen and the remainder hydrocarbon radicals or all four symbols may represent hydrocarbon radicals also either R1 and R2 or R3 and R4\t may jointly with the carbon atom to which they are linked represent an alicyclic ring and further, R1 and R3 may jointly with the respective carbon atoms to which they are linked represent an alicyclic ring.  The tertiary olefine may suitably have from 4 to 24 carbon atoms per molecule or may be an olefin polymer having from 6 to 16 carbon atoms per molecule.  The halide formed has the halogen atom which may be chlorine, bromine, fluorine, or iodine, attached to the terminal carbon atom of an ethyl radical which is attached to the or one of the tertiary carbon atom or atoms which was or were unsaturated in the original tertiary olefine.  Any ethyl halide and/or tertiary halide that may be formed may be recovered from the product and recycled to the reaction zone.  The process may be carried out in batch operation in the liquid phase with a liquid or suspended catalyst, good results being obtained by introducing the catalyst as a slurry into the tertiary olefine feed which is fed into an autoclave and agitated thoroughly while the ethylene and hydrogen halide are added in anhydrous form.  Continuous or intermittent reaction can be carried out by effecting countercurrent or concurrent contact of the reactants with the catalyst in suitable towers or other mixing devices.  Instead of operating in the liquid phase gaseous or mixed liquid and gaseous reactants may be used.  A preferred method of carrying out the process continuously comprises feeding ethylene, a tertiary olefine, preferably mixed with a diluent, hydrogen chloride, and an aluminium chloride-hydrocarbon complex into a mixer from which the reacted mixture overflows into a separator where the catalyst is separated from the organic layer which is then processed for recovery of the product.  Suitable proportions for the reactants are 0.5 to 2 moles of tertiary olefine and 0.5 to 1.5 moles of ethylene per mole of hydrogen halide, an excess of the tertiary olefine over the ethylene being preferably used.  The reaction is preferably carried out at between -20 DEG  C. and +20 DEG  C. when aluminium chloride or an organic complex thereof is employed as catalyst.  Less active catalysts require higher temperatures but in all cases it is desirable to maintain the temperature below 100 DEG  C.  The reaction may be carried out at atmospheric pressure but it is preferred to employ superatmospheric pressure, e.g. of 25 to 600 pounds per square inch gauge and the use of diluents such as saturated hydrocarbons is advantageous.  The catalyst is generally used in an amount of 0.2 to 2.5 per cent by weight of the olefinic reactants, based on the metal halide content of the catalyst and after separation the catalyst may be repeatedly recycled to the reaction zone.  The metal halide catalyst employed should preferably correspond to the hydrogen halide used, thus for the production of a primary chloride a metal chloride is preferred while aluminium bromide is preferred when using hydrogen bromide. Other catalysts specified are ferric, titanium, stannous, stannic and bismuth chlorides and the catalyst may be used in solid form such as lumps, granules, or finely-divided powder or may be deposited on supports or carriers.  Catalysts in the liquid state may also be used, e.g. organic complexes of Friedel-Crafts type catalysts and ketones or metal halide-alkyl halide complexes such as may be prepared by refluxing a tertiary alkyl halide with the corresponding aluminium halide.  Other suitable complex catalysts are those formed by the union of Friedel-Crafts type catalysts with hydrocarbons which may be aliphatic or aromatic, or mixtures of hydrocarbons.  Double salts of aluminium chloride such as are described in Specification 358,068, and complexes or sludges formed in the course of the reaction, after addition of fresh metal halide thereto, may also be used.  In examples: (1) ethylene is reacted continuously in a turbo-mixer with hydrogen chloride and isobutylene to yield 1-chloro-3,3-dimethylbutane and with hydrogen chloride and propylene polymers (boiling range 75-95 DEG  C.) to yield primary alkyl chlorides consisting of a mixture of octyl, nonyl and decyl chlorides, the reaction being carried out in each case in the presence of a catalyst consisting of an aluminium chloride complex prepared by refluxing an excess of technical grade kerosene with powdered anhydrous aluminium chloride in the presence of a slow stream of hydrogen chloride. Each reaction is carried out at -10 DEG C. and at elevated pressure in the presence of n-pentane as diluent; (2) the reaction is carried out in batches in a mild steel autoclave using an aluminium chloride-kerosene sludge containing added aluminium chloride as catalyst, ethylene and hydrogen chloride being reacted with tertiary amylenes (no diluent used) to yield a primary heptyl chloride and with methyl-1 cyclohexene-1 to yield 1-chloro-2-methyl-cyclohexylethane.  It is stated that di-isobutylene, ethylene and hydrogen chloride can be reacted under similar conditions to give 1-chloro-3,3,5,5-tetramethylhexane. Aromatic hydrocarbon radicals may be present as substituents in the tertiary olefine used, thus alpha-methyl-styrene, ethylene and hydrogen chloride yield 1-chloro-3,3 - dimethyl - 3 - phenylpropane. U.S.A. Specification 2,295,977 is referred to.