United States Patent Office Patented Mar
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3,499,882 United States Patent Office Patented Mar. 10, 1970 2 the formula TiXCH-CHTiX3 of the formula 3,499,882 TiXCHTiX. The reaction product DIENE POLYMERIZATION PROCESS AND CATALYST THEREFOR TiXCH-CHTiX3 Walter Nudenberg, West Caldwell, N.J., Dudley B. Merri field, St. Louis, Mo., and Edward Axel Delaney, Dover, 5 is a dimer of the CHTiX free radical while the re N.J., assignors to Texas-U.S. Chemical Company, Port Neches, Tex., a corporation of Delaware action product TiXCHTiX is formed by reaction of the No Drawing. Application June 19, 1963, Ser. No. 288,877, CHTiX"free radical with a TiX"free radical. which is a continuation-in-part of application Ser. No. A feature of this invention involves the use of a C-C6 38,417, June 24, 1960. Divided and this application 10 monoolefin as a component of the solvent mixture in Sept. 13, 1966, Ser. No. 578,995 which the butadiene polymerization is effected. The use of The portion of the term of the patent subsequent C-C monoolefins which have high heat capacity as co to Jan. 28, 1986, has been disclaimed solvents with an aromatic hydrocarbon solvent has the Int, C. C08d 3/08, 1/14 advantage of reducing the solution viscosity with the result U.S. C. 260- 94.3 10 Claims that it is possible to obtain better heat transfer during the 15 polymerization and to continue the polymerization to a This invention relates to a process for polymerizing higher solution solids content. The use of a C-C mono butadient to produce cis-polybutadiene of controlled 1,4 olefin as a cosolvent also results in the formation of cis structure. More particularly, this invention is directed to 1,4 polybutadiene with less tendency to flow during a process for polymerizing butadiene to polybutadiene of 20 storage and having a narrow molecular weight range. An cis-1,4 structure employing a novel catalyst and to other advantage resulting from the use of the C-C6 mono methods of preparation of this novel catalyst. olefin as a cosolvent with an aromatic hydrocarbon sol The subject application is a division of our commonly vent is increased catalyst efficiency. Employing C-Cs assigned co-pending application Ser. No. 288,877 filed monoolefins as cosolvents, it is possible to reduce the June 19, 1963 (now abandoned), which was a continu 25 catalyst requirement by /3 to /2 of that required if the ation-in-part of our commonly-assigned co-pending ap polymerization process of the invention is effected in a plication Ser. No. 38,417, filed June 24, 1960 (now solvent consisting of aromatic hydrocarbons. It is not abandoned). feasible to Substitute alkanes for the C-C monoolefins as Conjugated diolefin polymers of controlled structure cosolvents because their use results in substantial in have been prepared with catalyst systems comprising mix 30 solubility of the active catalyst resulting from the reaction tures of aluminum alkyl and titanium tetrahalide. Cis-1,4 of the organomagnesium compound, titanium tetrahalide polybutadiene prepared with aluminum alkyl-titanium and butadiene and a corresponding decrease in catalyst iodide catalyst systems have recently been made available effectiveness. - in commercial quantities and are being widely used as The preferred monoolefin cosolvent is isobutylene but blending agents for SBR and natural rubber. A serious 35 other monoolefins such as propylene, butene-2, pentene-1, limitation of the aluminum alkyl system is its tempera pentene-2, 2-methyl butene-2, hexene-1,3-methyl pentene ture sensitivity. At polymerization temperatures above 20 2, 2-ethylbutene-2 and mixtures thereof can be employed C., the cis content of the polymer decreases and molecular as the cosolvents with the aromatic hydrocarbons. The weight control is difficult to attain with aluminum alkyl C3-C6 monoolefin cosolvent is employed in a concentra systems. Aluminum alkyl-titanium halide catalyst systems 40 tion equivalent to 0.2 to 1.0 volume per volume of and other catalyst systems containing titanium halides in aromatic hydrocarbon solvent. In order to prevent forma combination with reducing agents are useful for the tion of cis-polybutadiene-olefin copolymers, the con polymerization of olefins such as ethylene and propylene. centration of the Ca-C6 cosolvent should not exceed ap In these catalyst systems the active catalyst components proximately five times the concentration of the butadiene is said to require solid TiX or some other reduced form 45 monomer. As disclosed in our copending application Ser. of titanium in which the titanium is in a valence state of No. 163,855, filed Jan. 2, 1962, cis-polybutadiene-isobutyl 3 or below. Various metal alkyls and metal hydrides such ene copolymers are formed using the catalyst obtained by as aluminum alkyls, dialkyl magnesium compounds, reaction of an organomagnesium compound, titanium dialkyl zinc compounds, Grignard reagents, lithium hy tetrahalide and butadiene employing a monomer reaction dride, etc. are used to reduce the titanium tetrahalide to 50 mixture containing 5 or more volumes of isobutylene per a valence state below 4, that is, to a valence state of 2 or volume of butadiene. 3. The subject invention involves the discovery that re The organomagnesium compound, which reacts with duced forms of titanium halides containing titanium in a butadiene and titanium tetrahalide to form the active valence state below 4 in admixture with organomagnesium catalyst containing tetravalent titanium, has the formula compounds are completely inactive for cis polymerization 55 RMgX or R2Mg wherein R is a hydrocarbyl radical con of butadiene and that polymerization of butadiene to a taining 1 to 30 carbon atoms and X is a halogen which polymer of cis 14 structure is effected with a catalyst con may be either chlorine, bromine, iodine or fluorine. The taining titanium essentially in a tetravalent state and R radical is preferably an alkyl or aryl hydrocarbyl radi prepared by reaction of an organomagnesium compound, cal containing 6 or more carbon atoms and the X is pref titanium tetrahalide and butadiene. 60 erably iodine, bromine or chlorine in the RMgX formula. In accordance with this invention, polybutadiene hav Examples of the organomagnesium compounds which re ing a cis content above 70% is prepared by polymerizing act with butadiene and titanium tetrahalide to form the butadiene in a solvent at a temperature between -10 and CHTiXa free radical which catalyzes butadient polym 90° C. with a catalyst containing titanium essentially in erization are the following: the tetravalent state and prepared by reaction of an 65 Effective Grignard reagents are dodecyl magnesium organomagnesium compound, titanium tetrahalide and iodide, dodecyl magnesium bromide, stearyl magnesium butadiene. The active catalyst for cis-polybutadiene manu iodide, ethyl magnesium bromide, ethyl magnesium iodide, facture produced by the reaction of an ether-free organo methyl magnesium iodide, nonyl magnesium iodide, naph magnesium compound, titanium tetrahalide and butadi 70 thyl magnesium bromide, phenyl magnesium bromide, ene is a free radical having the formula C4HgTiX3, phenyl magnesium chloride, tolyl magnesium bromide, wherein X is halogen, or a reaction product thereof having n-octyl magnesium iodide, t-octyl magnesium bromide, 3,499,882 3. 4. hexadecyl magnesium chloride and propargyl magnesium radical catalyst and its reaction products in which ti bromide. tanium is essentially in the tetravalent state is the "in Effective dihydrocarbyl magnesium compounds are di situ' procedure in which the organomagnesium compound dodecyl magnesium, diphenyl magnesium, di-tolyl mag and titanium tetrahalide are contacted in a hydrocarbon nesium, di-2-ethylhexyl magnesium, di-naphthy magnesi mixture containing the butadiene reactant. Usually the um, phenyl naphthyl magnesium and phenyl benzyl mag organomagnesium compound is dispersed and/or dissolved nesium, in a mixture comprising butadiene and hydrocarbon Sol Titanium tetrahalides employed in preparing the active vent and a hydrocarbon solution of titanium tetrahalide free radical CHTiX3 catalysts and its reaction products is added to the mixture comprising butadiene, organomag are exemplified by the following: titanium tetraiodide, nesium compound and solvent. As pointed out previously, titanium tetrabromide, titanium tetrachloride, titanium O the organomagnesium compound-titanium tetrahalide-bu tetrafluoride, mixtures thereof and also mixed tita tadiene reaction mixture contains butadiene monomer in nium tetrahalides such as titanium dichloride diiodide, amount equivalent to at least 300 mols and preferably at titanium dibromide diiodide and titanium monobromide least 500 mols of butadiene per mol of titanium tetra triiodide. The titanium iodides are preferably used when 5 halide reactant. The use of the butadiene reactant in a high cis content polymer is a desired product of the such a large mol excess assures the production of the butadiene polymerization as will be pointed out hereafter. active CHTiX free radical catalyst and prevents reduc The formation of the active catalyst, the CHTiX3 tion of the titanium halide by the organomagnesium con free radical or its reaction products, is effected by reaction pound to an inactive solid polymeric trihalide in which of organomagnesium compound, titanium tetrahalide and titanium is essentially in the trivalent state. butadiene in a solvent in the following proportions: ti 20 This procedure is characterized by high catalyst effi tanium tetrahalide-1 mol, organomagnesium com ciency, excellent reproducibility