United States Patent Office Production of Polymerized Wny, Alky, Ethers
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Patented Nov. 4, 1952 2,616,879 UNITED STATES PATENT OFFICE PRODUCTION OF POLYMERIZED WNY, ALKY, ETHERS ... Abraham. Oscar Zoss, Easton, Pa., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application July 2, 1946, Seria No. 681,29. 2 Claims. (C. 260-911) 2 This invention relates to the production of desired, the catalyst can be added to the mixture resilient, rubberlike polymers, more particularly of vinyl ether monomer and the hydrogen-con from vinyl alkyl ethers. - - - taining halogenated alkane gradually and in small Polymerization of vinyl ethers, among then amounts with continuous stirring while maintain vinyl methyl ether, by means af acid-reacting ing the temperature above -70° C. By so con catalysts has been described in U. S. P. 2,104,000. trolling the conditions of the reaction, a smooth. The products obtainable by the process of this and even rate of reaction is attained which is patent which is to be carried out at temperatures conducive to the maintenance of the necessary of about 10° C. and above are neither crystalline low reaction temperatures. - nor form-stable, rubbery polymers but range from Any suitable means of refrigeration may be liquid to Semi-solid products.lacking in physical employed for cooling of the reaction, for example, properties as substitutes for rubber. Solid carbon dioxide may be fed periodically to the I have found that by carrying out the poly reaction mixture, or part of the liquid diluent merization of a vinyl ether using a hydrogen may be allowed to vaporize by application of a containing halogenated alkane as the diluent at 5 vacuum to the reaction, the diluent being con temperatures maintained below about -30° C. densed and recycled to the reaction vessel or a rubber-like, form-stable polymers. Which are liquid refrigerant, such as chilled ethylene, may tough, resilient and non-tacky Solids are obtained. be circulated about the reaction vessel, or a com The vinyl ethers which can advantageously be bination of these means may be employed. The polymerized in accordance with the process of this 20 polymerization can also be carried out under invention include the lower alkyl vinyl ethers, Superatmospheric pressure, particularly when a e.g., methyl Vinyl ether, ethyl vinyl ether, propyl diluent, such as ethane which boils below -70° C., vinyl ether, isopropyl vinyl ether, butyl vinyl is employed. In general the reaction is carried ether, isobutyl vinyl ether and secondary and ter out at atmospheric pressure. tiary butyl vinyl ethers. Particularly valuable re 2 Hydrogen-containing halogenated alkanes Sults are obtained when vinyl alkyl ethers in which which can be employed include methyl chloride, the alkyl radical contains from 1 to 2 carbons are methylene chloride, chloroform, monochlorodi polymerized according to my process, since vinyl fluoronethane, ethylchloride, ethylene dichloride, methyl ether and vinyl ethyl ether do not poly ethylidene dichloride and the luke. Other hydro merize readily at temperatures below -30° C. 30 gen-containing halogenated alkanes can be emi when the diluents disclosed in the prior art are ployed in the process of the invention, especially employed. My process is also operative for the those having freezing points below -30° C. Par polymerization of other vinyl ethers such as those ticularly valuable results are obtained when hy disclosed in U. S. P. 2,104,000. drogen-containing chlorinated alkanes of one to It is essential that the temperature of the poly 35 tWO carbon atoms are used. The quantity of merization reaction be maintained below the hydrogen-containing. -halogenated alkane em aforesaid limit, as attemperatures thereabove the ployed as the diluent can be varied over a wide Vinyl ether is polymerized to lower molecular range. In general higher yields of polymer are weight products which are either too tacky or are obtained when from one to five moles of hydrogen not form-stable. In general the polymerization 40 containing halogenated alkane per mole of vinyl is carried out at temperatures between -70° C. ether are employed. Larger amounts of diluent and -60° C. since best results are obtained Within can be used but at a sacrifice in economy due to this temperature range. However, temperatures the cost of recovery of the diluent. - as high as -30° C. can be employed with some The hydrogen-containing halogenated alkane sacrifice in quality of the polymer. diluentS may be used in admixture with other To the attainment of the end that the reaction suitable diluents, for example, liquid or liquefiable temperature of the polymerization is maintained hydrocarbons, e.g., ethane, propane, butane, below the afore-mentioned limit, the reactants toluene, m-Xylene, saturated ethers, e.g., methyl and other materials employed in the process are ether, ethyl ether, butyl methyl ether, butyl ethyl brought, together under precooled conditions, ether and the like. The use of mixtures of di preferably at temperatures below -70° C., below luentS is particularly desirable when the hydro which temperature little or no polymerization gen-containing halogenated alkane employed occurs. By this method, the reactants can be freezes at temperatures above that employed for premixed and the temperature then raised to the polymerization of the vinyl ether. Mixtures of above -70° C. to effect the polymerization. If 55 diluents in which the polymer is insoluble can 2,616,879 3 4. advantageously be used to effect the precipitation matic hydrocarbons, chlorinated hydrocarbons, of the polymer as formed from the solution as alcohols, ketones, ethers and esters, for example, illustrated in Example II. in benzene, chlorobenzene, methanol, ethanol, As catalysts for effecting the polymerization, acetone, dioxane, ethyl ether, ethyl acetate, etc., acid-reacting condensing agents such as tin tetra 5 and in Water at temperatures below about 35 C. chloride, stannic chloride, aluminum chloride, The inventiori is further illustrated by the fol gallium trichloride, boron trifluoride and the like lowing specific examples to... which, however, it is may be employed. For best results, the use of not to be limited, Parts are by Weight. boron fluoride or its addition products. With Orr. Eacample I ganic oxygen-bearing compounds, such as ethers, 0. more particularly the addition products. Of the A reactor fitted with a stirrer, thermometer, diaikyl ethers, such as boron fluoride diethyl ether means for adding the catalyst and a went was and boron fluoride dibutyl ether, are recom. cooled in a Solid carbon dioxide-methanol bath nended. The addition compounds of boron fluo and 20, parts of liquefied methyl vinyl ether and ride may suitably be dissolved in a further quan 15 80 parts of methylene chloride were added. To tity of the organic oxygen-bearing compound this mixture was added with stirring 0.2 part of forming part thereof, e. g., the dialkyl ethers. boron fluoride diethyl ether complex while main The quantities of Catalyst used are generally be: taining the mixture at -74°C. The temperature was then raised to and maintained at -70° C. tween 0.001 and 10 per cent by weight of the vinyl for 1 hour during which time polymerization oc ether. For best results catalyst quantities within 20 curred. A precooled mixture of 40 parts of meth the range of 0.08 to 5 per cent are employed. anol, and 5 parts of concentrated ammonium hy Completion of the reaction may be determined droxide was then added with stirring and the by the absence of heating or discoloration in a contents of the reactor allowed to come to room sample of the reaction mixture to which a small temperature. The insoluble inorganic. products portion of the catalyst has been added. Where 25 were then removed by filtration, the methylene. the addition compounds or organic oxygen-bear chloride evaporated and polyvinyl methyl ether. ing compounds with boron fluoride are used, it is precipitated by the addition of water heated to recommended that they be drawn from such as above 35° C. After drying, an excellent yield of have been distilled under vacuum and freshly transparent, Colorless, tough, resilient, rubbery, made or stored under refrigeration as Such 30 form-stable polymer was obtained. X-ray ex measures insure greater retention of their cata amination of the polymer gave a, crystalline. X lytic activity. ray diffraction pattern.in-contrast, to a non-crys It is aesirable to conduct the polymerization in talline. X-ray diffraction pattern for methyl the essential absence of oxygen, that is, in an vinyl ether polymers prepared by the method of atmosphere of an inert gas Such as nitrogen or 35 cargon dioxide, the latter being conventionally U.S. P: 2,104,000-2,104,002. provided by the addition of solid carbon dioxide Similar results: are obtained. When methyl chlo-. to the reaction mixture followed by: venting for ride and ethyl chloride... are used as the diluent. removal of air; in place of methylene; chloride. When the polymerization has been finished, the 40 Eacample II catalyst is inactivated or quenched by working the polymer with substances which bind or Areactor similar to that described in Example otherwise stop the activity of the catalyst, for I was cooled by means: of a., bath, containing a example, aqueous solutions of alkaline-reacting mixture of Solid carbon dioxide: and methanol. substances, such as ammonium hydroxide, So To this reactor. Was: added 116 parts of liquefied dium hydroxide, potassium hydroxide; methyl 45 methyl vinyl ether, 170 parts, of methylene. chlo amine, ethyl amine, propyl amine, and the like. ride and 294 parts of liquefied propane. During. Organic hydroxyl and carbonal compounds, for a period of 40 minutes, 4. parts. of borontrifluo example, methanol; acetone, etc., are also effec ride-diethyl ether complex, was added to the tive quenching agentS.