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2,924,561 United States Patent Office Patented Feb. 9, 1960 2 ethylene is important commercially as a plastic. Styrene, a liquid, can also be polymerized to form polystyrene, a 2,924,561 well known plastic. Other olefins may also undergo POLYMERIZATION OF UNSATURATED polymerization to form resins or plastics which find com ORGANC. COMPOUNDS mercial use in many ways. Unsaturated organic compounds which may be poly Louis Schmerling, Riverside, E., assignor, by mesne as merized according to the process of this invention include signments, to Universal Oil Products Company, Des alkenes and preferably 1-alkenes such as ethylene, pro Plaines, Ill., a corporation of Delaware pene, butene-1, pentene-1, hexene-1, heptene-1, etc.; No Drawing. Application October 25, 1956 O cycloalkenes such as cyclopentene, cyclohexene, cyclo Seriai No. 618,191 heptene, etc.; aryl alkenes such as styrene, allylbenzene, etc. The polymerization of the aforesaid unsaturated 16 Claims. (C. 204-162) organic compounds is carried out by passing said com pound over a metallic oxide catalyst at a temperature in : 15 This invention relates to a method for polymerizing the range of from about 30 to about 350° C. under unsaturated organic compounds and more particularly ultraviolet light irradiation. If so desired, the olefins may to a process for polymerizing olefinic hydrocarbons. be passed over the catalyst as such or, in the presence of It is an object of this invention to provide a novel a substantially inert organic diluent such as a paraffin, method for polymerizing unsaturated organic compounds. a cycloparaffin or an aromatic hydrocarbon, examples A further object of this invention is to provide a novel 20 of said diluents including pentane, hexane, heptane, etc., method for polymerizing alkenes and cycloalkenes by cyclohexane, methylcyclohexane, etc., benzene, toluene, treating said alkenes and cycloalkenes in the presence of Xylene, etc. "a solid catalyst and ultraviolet light. The catalyst, which is to be used in the process of this One embodiment of this invention resides in a process invention is a metallic oxide, the preferred oxides being rfor the polymerization of unsaturated organic compounds 25 those which absorb strongly in the ultraviolet region and r which comprises heating said compounds in the presence include zinc oxide, cadmium oxide, titanium dioxide, of a metallic oxide and ultraviolet light, and recovering zirconium dioxide, antimony trioxide, arsenic trioxide, the resultant polymerized compound. etc. It is contemplated within the scope of this invention A further embodiment of the invention is found in a that the catalyst may be activated before use by irradiat : process for the polymerization of an alkene which com 30 ing said catalyst in ultraviolet light in the presence of prises heating said alkene to a temperature in the range water or certain hydroxy substituted organic compounds of from about 30 to about 350° C. in the presence of such as ethylene glycol, propylene glycol, phenol, resor a metallic oxide and ultraviolet light of from about 2000 cinol, hydroquinone, methyl alcohol, ethyl alcohol, propyl to about 3500 A., and recovering the resultant poly alcohol, etc. merized alkene. 35 The process of this invention may be effected in any Yet another embodiment of the invention is found in suitable manner and may comprise either a batch or a a process for the polymerization of an unsaturated or continuous type operation. For example, when a batch ganic compound which comprises heating said compound type operation is used a quantity of the unsaturated or to a temperature in the range of from about 30 to about ganic compound, if in liquid form, is placed in an appro 350° C. in the presence of an inert organic diluent, a 40 priate condensation apparatus provided with heating and metallic oxide and ultraviolet light of from about 2000 stirring means, along with the particular metallic oxide to about 3500 A., and recovering the resultant poly which has been selected as the catalyst. A source of ...merized compound. ultraviolet light is placed adjacent the apparatus (fitted A specific embodiment of the invention resides. in a with a window which transmits ultraviolet light) so that process for polymerizing propene which comprises heat 45 the light emanating from said source will irradiate the ing said propene to a temperature in the range of from catalyst and unsaturated organic compound. The flask about 30 to about 350° C. in the presence of zinc oxide is heated to the desired temperature and maintained and ultraviolet light of from about 2000 to about 3500 thereat for a predetermined residence time, at the end A., and recovering the resultant polymerized propene. of which time the flask and contents thereof are cooled Other objects and embodiments referring to alternative 50 to room temperature and the polymerized material is talkenes and cycloalkenes and to alternative metallic separated from any unreacted starting materials. If the oxide catalysts will be found in the following further unsaturated organic compound is in gaseous form a quan detailed description of the invention. tity of the catalyst is placed in an appropriate apparatus Heretofore, the usual methods of polymerizing unsat such as an autoclave containing an ultraviolet source, urated organic compounds such as olefins or cycloolefins 55 the autoclave is sealed and the unsaturated compound was to heat said compounds in the presence of a peroxide is pressured in, the reaction being continued for a pre or of an acid-acting catalyst either of the solid or liquid determined period of time, at the end of which time the type, such catalysts including sulfuric acid, aluminum autoclave and contents are cooled, the excess pressure chloride, boron fluoride, phosphoric acid, phosphoric is vented and the polymerized compound is recovered. acid composited on a solid siliceous adsorbent, etc. How 60 Another method of effecting the process of the present : ever, it is now proposed that according to the present invention is a continuous type operation. In this type process the unsaturated organic compounds be poly the unsaturated organic compound is continuously passed merized by heating said compounds in the presence of through a suitable reaction tube (for example a quartz a metallic oxide catalyst which is subjected to irradiation tube) containing the metal oxide catalyst and irradiated by ultraviolet light of from about 2000 to about 3500 with ultraviolet and maintained at the desired tempera Angstrom units. ture. The tube may be held in horizontal position and Polymerized organic compounds which are prepared contain a layer of catalyst which is heated and irradiated according to the process of this invention find a wide while the unsaturated compound is passed over it. The variety of uses in the chemical and allied fields. Nor reaction product comprising the polymerized compound mally gaseous alkenes such as propene and the butenes O is continuously withdrawn and purified by conventional are polymerized for use in motor fields. Another-gaseous means while any unreacted starting materials may be re olefin, ethylene, when polymerized to solid form as poly cycled to form a portion of the feed stock. One particu 2,924,561 3 4. lar type of continuous operation comprises a fixed bed to a temperature in the range of from about 30 to method in which the catalyst is disposed as a fixed bed about 350° C. in the presence of a metal oxide selected in the reactor and the polymerizable unsaturated organic from the group consisting of zinc oxide, cadmium oxide, compound is passed therethrough in either an upward titanium dioxide, zirconium dioxide, antimony trioxide or downward or horizontal flow. Another type of oper and arsenic trioxide irradiated with ultraviolet light of ation which may be used is the fluidized type in which from about 2000 to about 3500 A. during the polymeri the catalyst and the unsaturated organic compound are zation, and recovering the resultant polymerized com maintained in a state of turbulence under hindered set pound. tling conditions. Yet another type of operation com 4. A process for the polymerization of an alkene which prises the slurry type in which the catalyst is carried into O comprises heating said alkene to a temperature in the the reactor as a slurry in the polymerizable organic com range of from about 30° to about 350° C. in the presence pound. As hereinbefore set forth, the catalyst is irra of a metal oxide selected from the group consisting of diated by the ultraviolet light while passing through the zinc oxide, cadmium oxide, titanium dioxide, zirconium reactor. In all cases the reaction product is separated dioxide, antimony trioxide and arsenic trioxide irradiated from the reactor effluent while the unreacted starting 5 with ultraviolet light of from about 2000 to about 3500 materials are recycled to form a portion of the feed A. during the polymerization, and recovering the re stock. sultant polymerized alkene. The following examples are given to illustrate the proc 5. A process for the polymerization of a cycloalkene ess of the present invention which, however, are not which comprises heating said cycloalkene to a tempera intended to limit the generally broad scope of the present 20 ture in the range of from about 30 to about 350° C. in invention in strict accordance therewith. the presence of a metal oxide selected from the group Example I consisting of zinc oxide, cadmium oxide, titanium dioxide, zirconium dioxide, antimony trioxide and arsenic trioxide 35 g. of zinc oxide which have been previously irradiated with ultraviolet light of from about 2000 to irradiated by exposure to the rays of an ultraviolet light 25 about 3500 A., during the polymerization, and recovering source are placed in a quartz tube which is irradiated the resultant polymerized cycloalkene. by means of an ultraviolet lamp at a distance of two 6.
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