United States Patent Office Patented Aug
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y 2,847,481 United States Patent Office Patented Aug. 12, 1958 2 invention produces a mixture of these isomers from which the desired CsCl isomer may be separately re 2,847,481 covered in substantially pure form. Apparently, the PRODUCTION OF OCTACHELOROMETHYLENE preparation of octachloromethylenecyclopentene has CYCLOPENTENE been of only academic interest as no attempt has been made to obtain the material by an economic process Aylmer H. Maude and David S. Rosenberg, Niagara suitable for commercial manufacture. Falls, N.Y., assignors to Hooker Electrochemical Com Octachloromethylenecyclopentene is a valuable chem pany, Niagara Falls, N.Y., a corporation of New York ical intermediate, useful in the synthesis of various other No Drawing. Application August 9, 1954 0 chemicals having diverse uses in the commercial arts. Serial No. 448,736 For example, it may be used as the starting material for making perchlorofulvene by reacting it with aluminum 5 Claims. (CI. 260-648) shavings in the presence of freshly sublimed aluminum chloride in ether solution for a period of about 12 hours This invention is concerned with the production of 5 (see Roedig, Ann. 569, 161-183, (1950)). Also, various unsaturated cyclic chlorocarbons having the empirical ketones may be made from octachloromethylenecyclo formula CsCl and more particularly to the production pentene by reaction with sulfuric acid. of octachloromethylenecyclopentene. The process of It is the object of this invention to provide a method the present invention involves introducing a mixture for the production of octachloromethylenecyclopentene of a C chlorohydrocarbon containing at least three 20 by an economic process which has a direct and simple chlorine atoms and chlorine into a reaction Zone con procedure and which is readily adaptable to commercial taining a porous surface active catalyst maintained at operation. It is a further object to provide a method an elevated temperature to produce the CsCls chloro for the production of octachloromethylenecyclopentene carbon in the desired yield. from inexpensive starting materials. Other objects will One isomer of CsCl was first produced by H. J. Prins 25 become apparent to those skilled in the art on considera (J. Prakt. Chem. (2) 89, 421 (1914)). This isomer tion of our complete specifications and claims. melting at 183 degrees centigrade has the following We have now found that these and related objects theoretical structural formula: are accomplished by reacting chlorine with a C6 chloro Cl-C C-Cl hydrocarbon having at least three chlorine atoms in the C-C-Cl 30 presence of a porous surface active catalyst at tem peratures between about 250 and 460 degrees centigrade. Cl-C C-Cl The starting C6 chlorohydrocarbon must have at least and is designated as octachloromethylenecyclopentene. three chlorine atoms; however, the exact ratio of hydro Prins prepared it from hexachloropropylene using cop gen to chlorine atoms is not critical. Any Cs chloro per-bronze in methanol solution (see also Rec. Trav. hydrocarbon containing more than three, and preferably Chem. 51, 1065 (1932) and 72, 253-261 (1953)). A about eight to nine chlorine atoms may be employed in Roedig (Experimentia 4, 305-307 (1948)) prepared the practicing our invention. Various Ca hydrocarbons may compound from hexachloropropylene using aluminum be used as starting materials for preparing the chloro shavings in ethereal solution. Further (Ann. 569, 161 hydrocarbon; for example, n-hexane, iso-hexane, meth 183 (1950)), Roedig again prepared the compound by 40 ylcyclopentane, as well as the corresponding olefins and dechlorinating either octachloropropane or hexachloro diolefins, and mixtures thereof. propene with aluminum powder. Prins also prepared When carrying out the reaction, the proportion of free the compound from these same two starting materials chlorine to employ is slightly (about 10 percent) more and in addition from heptachloropentene-1 (Rec. Trav. than the theoretical amount required to make octachloro Chem. 65, 435 (1946)). Prins later made the isomer methylenecyclopentene from the chosen starting mate of CsCl of melting point 183 degrees centigrade by two rials. While a slight excess of chlorine (about 10 per different methods (a) action of copper powder upon cent) is desired, a higher percentage will not prove detri hexachloropropene in alcoholic solution, and (b) reac mental to the reaction, but the amount of chlorine will tion of chloroform and trichloroethylene in the presence be governed by economics of the process. The following of aluminum chloride (Rec. Trav. Chem. 68, 419-425 50 equations are illustrative of this point. (1949)). The prior art refers to isolation of three of the four possible structural isomers of CsCls having melting points of 45, 94, and 183 degrees centigrade. These structural Materials selected from the group consisting of silica isomers of empirical formula CsCls may have any of 55 gel, bauxite, active carbon, kieselguhr brick, fuller's the following theoretical configurations: earth, floridin, attapulgite, diatomaceous earth and mix Cl-C C-Cl2 . Cl-C C-Cl2 tures thereof are suitable porous surface active solids for use in this invention. These solids all have exten =C-Cl CeC-Cl sive active surface areas and are substantially unaffected C-C C-Cl Cl-C -Cl 60 chemically during their life in the reaction zone. They II tend to become ineffective in use, probably due to re duction in porosity, and must be periodically replaced Cl-C C-Cl Cl-C C-Cl by fresh material. In general, the low cost of such C-C-Cls C Cl-C-Cla solids renders it uneconomic to regenerate them when 65 spent, but this can be done if desired. Cl- -Cla C-C TC-Cl The porous inorganic solid employed in the reaction III IV Zone can be pretreated by various techniques, such as, These isomers are believed to be interconvertible. Al extrusion under pressure, acid extraction, impregnation though the present invention relates primarily to the with various salts, etc., whereby enhanced results are production of octachloromethylenecyclopentene which 70 obtained in this invention. is believed to have the structural formula correspond The porous solids may be impregnated with the chlo ing to configuration I above, the process of the present ride salts of various metals to enhance their activity; for 2,847,481 3. example, iron, cobalt, or nickel, which are metals of from such preferred stock as n-hexane, iso-hexane, various group V of the periodic table. mixed hexanes, or methylcyclopentane. The exit from The reaction temperature should be maintained be the catalyst tube was connected to a condenser consist tween 250 and 460 degrees centigrade to obtain a high ing of a section of 2-inch nickel pipe holding a glass yield of octachloromethylenecyclopentene. The pre cooling thimble with water cooling. ferred range of temperature wherein we have obtained the A nominal retention time of about three to fifteen best results is between about 275 and 350 degrees centi seconds was used. The time was calculated as indicated grade. The most desirable temperature for any particu in the examples. lar starting material is that low enough for a minimum The organic product from the reactor was distilled in yield of hexachlorobenzene and high enough to reduce 0. a column (20 mm. bore and 4 feet high) packed with to a minimum hydrogen-containing, organic products. protruded nickel packing. Fractionation was carried out The porous solid in the fore portion of the reaction at an absolute pressure of about 10 mm. of mercury. zone is advantageously graded with lower activity mate Essentially pure octachloromethylenecyclopentene was ob rial where the reactant vapors first contact it to avoid an tained by crystallization from suitable solvents. excessively rapid exothermic reaction with a resulting 5 The following examples illustrate our invention but are temperature above the range indicated whereby chlo not to be construed as limiting the same to these ex rinolysis would result. The temperature should be main amples. tained fairly uniform and in order to accomplish this Example I condition it may be necessary to heat or cool the various About 1160 grams of n-hexane were photochemically reaction zones depending upon catalyst activity and the 20 chlorinated as above described to a specific gravity of exothermic or endothermic character of the reaction about 1.6 which corresponds to a product having an taking place in that Zone. For example, if chlorine con average molecular formula of C6H54Cls.6. tent of C chlorohydrocarbon feed were high, it may be A feed of 386 grams per hour (1.01 moles per hour) necessary to heat the entire reaction Zone; if low, cooling of such polychlorohexane and 348 grams per hour (4.9 may be required in the initial zone and heat in the final moles per hour) of chlorine was fed to a reactor tube, ZOC holding 720 cubic centimeters of catalyst of fine granular The undesirable effects of localized overheating in the fore portion of the reaction zone containing the porous particle size. The first quarter of the tube was charged solid, whereby chlorinolysis is effected, may be minimized with a mixture of 1 part pressure activated floridin and 30 6 parts pumice. The pumice used was inert in this re by diluting the gaseous reactants with an inert diluent. action and serves to reduce the activity per unit catalyst Hydrogen chloride concomitantly produced with the Cs volume. The second quarter of the tube was charged chiorohydrocarbons may be conveniently and advan with 1 part pressure activated floridin and 3 parts pumice. tageously used as an effective diluent for this purpose; The third and fourth quarters were packed with pressure however, other diluents such as nitrogen or carbon di 35 activated floridin alone. The retention time was about oxide can be used. seven seconds, calculated on a reaction temperature of The reactants are introduced into the reaction Zone in 300 degrees centigrade, on the molal feed rates and the the vapor state at substantially atmospheric pressure and free space in the catalytic bed.