Patented Mar. 2, 1954 2,671,079 UNITED STATES PATENT 2,671,079 PHosPHoRUS-conTAINING PolyMERs OFFICE William B. McCormack, Wilmington, Del, as signor to E. I. du Pont de Nemours and Com pany, Wilmington, Del, a corporation of Dela Wate No Drawing. Application August 7, 1951, Serial No. 240,813 1. 14 Claims. (CI260-92.3) This invention relates to new phosphorus-con taining interpolymers and to a process for obtain The dihalophosphine to be used in this process ing them. has the formula RPX2, in which R, represents a In my copending application Serial No. 240,814, member of the group consisting of alkyl, aryland there are described stable, heat-resistant poly aralkyl radicals and X represents a member of mers containing phosphorus in the form of phoS the group consisting of chlorine and bromine, phine oxide groups. These polymers are prepared The preferred phosphines are dichlorophenyl by the reaction of a hydroxyl-containing com phosphine and dichloroethylphosphine. A wide pound, such as Water or an alcohol, With a phoS variety of phosphine derivatives having the gene phorus-containing interpolymer in which the eral formula, shown may be employed. Represen phosphorus is present as dihalotertiaryphosphine O tative compounds include those in which R, rep groups. The latter interpolymers are the sub resents an alkyl group such as methyl, ethyl, ject of the present application. - propyl, butyl or octyl; an aryl group Such as It is an object of this invention to provide phenyl or alpha- or beta-naphthyl, or an aral polymeric products containing phosphorus, which kyl group such as benzyl or phenylethyl. In gen polymers may readily be converted to useful 5 eral, the lower members of these classes of radi polymers containing phosphorus in the form of cals are most useful. These compounds are read the stable phosphine oxide grouping. A further ily available from several well known procedures, object is to provide a process for the prepara Such as by the action of a phosphorus trihalide tion of these intermediate phosphorus-contain on a hydrocarbon in the presence of aluminum ing polymers. 20 chloride, or by the action of a phosphorus trihal According to the present invention, Such inter ide on dialkyl or diaryl mercury. Kharasch in J. polymers are prepared by contacting a polymer Org. Chem. 14, 429 (1949) describes a process for izable organic compound containing conjugated making dichloroethylphosphine from phosphorus olefinic double bonds with a mono-substituted trichloride and lead tetraethyl. The various pro dihalophosphine, in the presence of a free radi 25 cedures for making these compounds are Sum cal polymerization catalyst. marized in Kosolapoff, Organophosphorus Com The polymerizable compounds containing Con pounds, Wiley, N. Y. (1950), chapter 3. jugated olefinic double bonds which are useful The polymerization reaction is carried out with in the practice of this invention include hydro the aid of a free radical polymerization catalyst, carbons, such as butadiene, isoprene, 2,3-dimeth 30 such as an azonitrile, or a dialkyl or diacyl per yl-1,3-butadiene, 1,3-pentadiene, 2,4-hexadiene, oxide. The term “free radical polymerization 2,4-heptadiene, 2,5-dimethyl-2,4-hexadiene, myr catalyst” is also meant to include actinic radia cene, allo-ocimene, 2,6-dimethyl-1,3-heptadiene, tion, and particularly ultraviolet light. The 1,3-decadiene, 2-phenyl-1,3-butadiene, 2,3-di azonitrile catalysts which may be employed in phenyl-1,3-butadiene, 2-benzyl-1,3-butadiene, 35 this reaction are those set forth in detail in 1,1'-biscyclohexenyl, 2-tolyl - 1,3-butadiene, 1 United States Patent No. 2,471,959, to Madison vinyl - 1-cyclohexene, 1,2-dimethylenecyclohex Hunt and include alpha, alpha-azodiisobutyroni ane, 1,3,5-hexatriene, 1,3-cyclopentadiene and trile; alpha, alpha-azobis- (alpha-methylbutyl 1,3-cyclohexadiene; carboxylic acids, such as 2,4- ronitrile) ; alpha, alpha-azobis-(alpha-methyl pentadienoic acid (beta-vinylacrylic acid), sorbic 40 isocapronitrile) and the like. Suitable peroxide acid, muconic acid and eleostearic acid, and the catalysts include the dialkyl peroxides such as esters of such acids; halogenated hydrocarbons di(tert-butyl) peroxides, and the diacyl per such as 2-chloro-1,3-butadiene, 2-bromo-1,3-bu oxides such as butyryl, lauroyl and benzoyl per tadiene, 1-chloro-1,3-butadiene and the like; and oxides. The amount of catalyst which may be nitriles, such as 1-cyano-1,3-butadiene (beta 45 used may vary over a wide range from 0.1% by vinyl-acrylonitrile) and 2-cyano-1,3-butadiene. weight upwards. From 1 to 5% by weight of The term “olefinic double bond' is meant to in catalyst, based on the total weight of the mono clude any non-aromatic carbon-to-carbon dou meric reactants, is ordinarily desirable. The ble bond, whether occurring in an acycylic or in azonitriles represent the preferred class of cat a cycloaliphatic system. Preferred compounds 50 alysts. of this class are butadlene, isoprene, 2-chloro-1,3- Although the interpolymers of this invention butadiene, 2-bromo-1,3-butadiene and myrcene. are most efficiently prepared by the use of poly Mixtures of two or more of these compounds may merization catalysts of the type described, they be employed. - . may also be prepared without the use of cat 55 alysts. Under such conditions, lower yields and 2,671,079 4. 3 the converted adduct of butadiene and dichloro lower degrees of polymerization are obtained. In methylphosphine), but is ordinarily between my copending application Serial No. 240,807, a about 10 and 20%. Actually the interpolymer process is described in which conjugated dienes usually contains somewhat less phosphorus than are reacted with substituted dihalophosphines the theoretical. The heat resistance and hydro under conditions calculated to give monomeric philic character of the polymers containing phOS addition products. As there set forth, the reac phine oxide groups increase in proportion to the tions almost always yield some polymeric prod amount phosphorus present. As little as 0.1% ucts in addition to the monomers. phosphorus confers these properties on the poly The two reactants may be used in equimolecul ner to a determinable extent, while at 2% phos lar amounts or an excess of one reactant or the it) phorus the effect is pronounced. Interpolymers other may be used to serve as a reaction medium. containing from about 2 to 15% phosphine (be The amount of each reactant present is prefer fore conversion to the phosphine oxide) repre ably between 5 and 95% by weight of the total sent the preferred class of products made ac amount of reactants. If the diene is present in 5 cording to this invention, excess, the composition of the interpolymer will The invention is illustrated by the following ordinarily be affected to some extent, since the examples: excess material can take part in the polymeriza Eacample 1 tion. This is not true when the dihalophosphine is present in excess. Use of an excess of diene A mixture of 50.0 g (0.28 m.) of redistilled results in increased yields of polymer and in the dichlorophenylphosphine, 19.1 g. (0.28 m.) of formation of polymers of increased viscosity. The redistilled isoprene containing no inhibitor and reaction may be conducted in the presence of a 700 mg. of alpha, alpha'-azobis-(alpha-methyl non-reactive medium such as petroleum ether, isocapronitrile) is warmed at about 40 C. for cyclohexane, benzene, carbon tetrachloride, chlo twenty-four hours. During this time a cream roform and the like. The mixture should be colored solid gradually forms. A small amount free of substances capable of converting the di of residual liquid is decanted, and the solid is haio compounds to the corresponding oxides, such washed with petroleum ether, then hydrolyized as water, alcohols and carboxylic acids, with water to give a yellow-orange oil and the When chloroform is used as the reaction me mixture is neutralized with sodium hydroxide. dium, the polymerization proceeds with unusual 30 This oil is separated from the aqueous layer, rapidity and results in increased yields of poly washed with water and taken up in chloroform. ners having higher viscosities than polymers ob Evaporation of the chloroform and drying of the tained with the other common solvents. These residue at 90° C. (10 nm.) gives 19.6 g. of a clear polymers are also found to contain some chlorine, yellow-red vitreous resin. even after conversion of the dichlorotertiary Aralysis. - Calcd. for C11H13OP:P-16.1%. phosphine groups to phosphine oxide groups. Found: P=15.5%. Although the nature of this effect is not entirely The product is therefore substantially the 1:1 understood, it appears that the chloroform in heteropolymer, obtained in 37% conversion. By some way takes part in the polymerization re extraction of the aqueous hydrolysate layer with action, possibly by forming or aiding in the 40 chloroform, followed by distillation, there is ob formation of cross-linkages and in chain trans tained an 18% yield of liquid monomeric adduct fer, boiling at 160-165° C. (2 mm.). The polymers produced according to the pres Eacample 2 ent invention are white to light brown in color and vary in form from tacky to granular solids. The procedure described in Example is re By treatment with water, alcohol or a carboxylic peated to the point where the reaction mixture acid, they are readily converted to polymers in is hydrolyzed with water. The mixture is then which the phosphorus is present as phosphine salted and extracted with chloroform. The ex oxide groups, as described in copending applica tract, which contains both monomeric and poly tion Serial No. 240,814.