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. The phosphine oxide meric products, is distilled. After removal of the polymers are heat resistant and are useful as chloroform, a 44% yield of distilled nonOnner fameproofing and anti-static agents for textiles and a 47% yield of a yellow glassy hard poly meric residue are obtained. and in the manufacture of molded articles and An identical run omitting the catalyst gives a films.The molecular weights of the polymers, meas 75.5% yield of distilled monomer and 7.5% yield ured by osmotic pressure after conversion of the of polymeric residue. dihalotertiaryphosphine groups to phosphine Eacample 3 oxide groups are between 10,000 and 100,000. the polymers produced according to the pres A mixture of 50 g. (0.28 m.) of dichlorophenyl ent invention contain varying amounts of phos phosphine 50 ml. of cyclohexane, 19.1 g. (0.28 m.) phorus, since homopolymerization of the diene of redistilled isoprene and 0.7 g. of the catalyst may take place at the same time and in Com of Example 1 is warmed at 40° C. for eighteen petition with the interpolymerization. The ex hours. The cream-colored Solid is filtered, de tent to which the interpolymerization dominates composed with methanol, diluted with water and is a function of the reactivities of the specific 65 the insoluble polymer isolated from the water reagents under the particular reaction condi and dried at 100 C. for three days, to give 34.5 g. tions. The phosphorts content in most cases of a clear, glassy, yellow-brown resin. approaches the theoretical value for polymers in Eacample 4 which one mole of dihalophosphine has reacted A mixture of 25 g. (0.14 m.) of dichlorophenyi with One mole of diene. This value varies with phosphine in 25 ml. of thiophene-free benzene, the molecular weight of the reagents and is or 9.55 g (0.14 m.) of isoprene and 0.35 g. of the dinarily between 10 and 17%. After conversion catalyst of Example 1 is Warned at 40 C. for of dihalotertiaryphosphine groups to phosphine eighteen hours. The cream-colored Solid is fl oxide groups, the theoretical maximum phos phorus content may be as high as 26.7% (for 75 tered and treated with methanol. The evolution 5 a,671,079 of methyl chloride indicates that conversion of 6 dichlorotertiaryphosphine groups to phosphine three more days. The light brown solid which oxide groups is taking place. The mixture is forms is treated by filtration, decomposition with diluted with water and the separated polymer is methanol, and dilution with water to give an dried at 100° C. for three days to give 11.6 g. of insoluble oil, which on drying gives 40 g. of red a clear, glassy, brownish resin. dish polymer. Analysis.-Per cent P=13.3; per cent Cl-14.1. Eacample 5 Eacanople to Using a 4:1 mole ratio of reagents, a mixture of 38.2 g. (0.56 m.) of isoprene, 25.0 g. (0.14 m.) Warming a mixture of 50.0 g. (0.28 m.) of di of dichlorophenylphosphine in 50 ml. of cyclo 0. chlorophenylphosphine in 100 ml. Of cyclohex hexane and 0.7 g. of the catalyst of Example 1 ane, 34.4 g. (0.28 m.) of 2,3-dichloro-1,3-butadiene is warmed at 40° C. for eighteen hours, during and 1 g. of the catalyst of Example 1 at 60° C. which time a somewhat stringy white solid pre for One day gives a tan Solid product. This is cipitates. The mixture is filtered, hydrolyzed worked up by filtration and digestion with hot with water, washed and dried to give 18.4 g. of 15 methanol until there is no further evidence of . Solid interpolymer containing 15.0% phos reaction. Dilution. With Water and drying of phorus (theory for the 1:1 adduct=16.1%). cream-coloredthe resultant solidsolid. at 100° C. gives 27.7 g. of a Eacample 6 Analysis.-Cl=52.9%; P-1.7%. Using an 8:1 mole ratio of reagents, a mixture 20 Eacample 11 of 38.2 g. (0.56 m.) of isoprene, 12.5 g. (0.07 m.) of dichlorophenylphosphine and 50 ml. of cyclo When a mixture of 50.0 g. (0.28 m.) of di hexane and 0.5 g. of the catalyst of Example 1 chlorophenylphosphine in 50 ml. of cyclohex is Warmed at 40° C. for about twenty hours. The ane, 18.5 g. (0.28 m.) of cyclopentadiene and Stringy White Solid is isolated by filtration, de 25 0.5 g. of the catalyst of Example 1 is warmed at composed with warm aqueous methanol, diluted 35° C. for three days, a red brown Solid slowly with Water, and then washed with Water in a deposits. This solid is isolated by Washing With crude rubber mill, to give a cream-colored, plas petroleum ether, and is then decomposed with tic mass which is slightly rubbery. After drying, methanol and diluted with Water to give about there are obtained 13.0 g. of glassy solid contain 30 1.2 g. of solid (dry weight), containing 11.8%. P. ing 13.6% phosphorus. Extraction with chloroform of the aqueous layer from the decomposition and concentration Eacample 7 gives a reddish-brown oil which on drying in A mixture of 46.2 g. (0.26 m.) of dichlorophen vacuo at 100° C. gives 2.4 g. of a viscous oil con ylphosphine, 18 g. (0.26 m.) of isoprene, 0.5 g. 35 taining 14.4% P. . . of alpha, alpha'-azobis-(alpha-methylisocapro Eacample 12 nitrile) and 100 ml. of cyclohexane is warmed at 50° C. for twenty hours. The cream-colored solid A mixture of 25.0 g. (0.10 mi.) of (p-bromo which forms is filtered, treated with methanol phenyl)-dichlorophosphine in 50 ml. of cyclo to convert phosphorus dihalide groups to pho 40 hexane, 6.6 g. (0.10 m.) of isoprene and 0.75 g. phine oxide groups, and diluted with water. of the catalyst of Example 1 is warmed at 40° C. The resulting polymer is dried to give 22 g. of for twenty hours. A dull white solid forms. It is resinous product, having an intrinsic viscosity treated by filtration, washing with petroleum in methanol of 0.14. ether, decomposition with methanol and dilution This run is repeated under the same condi with water to give an insoluble material. This tions except that 100 ml. of chloroform are used is dried at 100° C. to give 18.2 g. of a practically in place of the cyclohexane and the reaction is white solid, containing 11.0% P and 28.3% Br. conducted for Seventeen hours at 40 C. The Eacample 13 product in this case weighs 47.5 g. and has an A mixture of 40.0 g. (0.305 m.) of dichloro intrinsic viscosity in methanol of 0.40. It con ethylphosphine in 50 ml. of cyclohexane; 20.8 g. tains 4.9% chlorine (after treatment with meth (0.305 m.) of isoprene and 0.70 g. of the cata anol and water). lyst of Example 1 is warmed at 40° C. for twenty A third run is made using chloroform in place hours. The white Solid product is obtained by of the cyclohexane and with a polymerization filtration of the reaction mixture. Hydrolysis of time of three hours at 40° C. The polymeric the solid with water gives an aqueous solution. product is obtained in a yield of 41.3 g. and has an Saturation with salt, extraction with chloroform intrinsic viscosity of 0.27. and concentration gives 18.4 g. of a brown brittle Eacample 8 glassy Solid containing 18.0% P. A mixture of 50.0 g. (0.28 m.) of dichloro 60 Eacample 14 phenylphosphine in 50 ml. of cyclohexane, 15, g. A mixture of 25.0 g. (0.19 m.) of dichloroethyl (0.28 m.) of butadiene and 0.50 g. of the catalyst phosphine in 50 ml. of cyclohexane, 25.4 g, of Example 1 is warmed at 40° C. in a Sealed (0.19 m.) of 2-brono-1,3-butadiene and 0.5 g. pressure bottle for two days. The resulting yell of the catalyst of Example 1 is warmed at 45° C. low brown Solid is filtered, decomposed with 65 for twenty hours. A light tan solid polymer is methanol, and diluted with Water to give an in formed. Filtration of the reaction maSS and hy soluble oil. Drying at 100° C. gives 6.1. g. of yell drolysis with water gives a heavy yellow oil which low Solid. is separated from the aqueous layer and dried to Eacample 9 give 21 g, of a yellow-brown resin containing A mixture of 100.0 g. (0.56 m.) of dichloro 12.3% P and 48.0% Br. phenylphosphine in 200 ml. of cyclohexane, 49.4 Eacample 15 g. (0.56 m.) of 2-chlorobutadiene-13 and 0.50 g. of the catalyst of Example 1 is warmed at 45° C. A mixture of 50.0 g. (0.28 m.) of dichloro for two days and then at room temperature for phenylphosphine and 50 ml. of cyclohexane 75 19.1 g. (0.28 m.) of isoprene, 14.8 g. (0.28 m.) of 2,671,079 8. 7. 3. A process according to claim 1 in which the acryionitrile and 0.50 g. of the catalyst of Ex polymerizable organic compound is Selected from. ample 1 is warmed at 40° C. for twenty hours. the group consisting of butadiene, isoprene, 2 Filtration of the cream-colored solid polymer, chloro-1,3-butadiene and 2-bromo-1,3-butadiene. conversion of the dichlorotertiaryphosphine to 4. A process according to claim 1 in which the the corresponding phosphine oxide With meth 5 polymerizable organic compound is butadiene. anol and dilution with water gives an oil. This 5. A process according to claim i in which the is separated, washed with water and dried to polymerizable organic compound is isoprene. give 20.0 g. of a transparent brownish glass, 6. A process according to claim 1 in which the containing 15.0% P and 0.9% N. polymerizable organic compound is 2-chloro-1,3- Eacample 16 O butadiene.7. The process of preparing a phOSphorus The process described in Example 3 is repeated, containing polymeric addition product which using ultraviolet light as catalyst instead of the comprises contacting butadiene with dichloro azonitrile catalyst. This gives 10.7 g. of poly phenylphosphine in the presence of a free radical meric dichlorophosphine. After conversion to 5 polymerization catalyst comprising an azonitrile the corresponding phosphine oxide the polymer and in the absence of substantial amounts of contains 15.9% P. hydroxyl-containing compounds. w When 500 mg. of dibenzoyl peroxide are used 8. The process of preparing a phosphorus as catalyst in place of the a Zonitrile or ultra containing polymeric addition product which violet light, there are produced 2.0 g. of a poly 20 comprises contacting isoprene with dichloro meric phosphine oxide containing 14.9% P. phenylphosphine in the presence of a free radical In the absence of any polymerization catalyst, polymerization catalyst comprising an azonitrile methanol-soluble interpolymers are obtainable and in the absence of Substantial amounts of by the reaction between dichlorophenylphosphine hydroxyl-containing compounds. and 1-cyano-1,3-butadiene, ethyl Sorbate, 1-(p- 25 9. The process of preparing a phosphorus nitrophenyl)-1,3-butadiene, 2-methoxy-1,3-bu containing polymeric addition product which tadiene, and 1-acetoxy-1,3-butadiene; and by the comprises contacting 2-chloro-1,3-butadiene with reaction between dichloronaphthylphosphine and dichlorophenylphosphine in the presence of a isoprene. 30 free radical polymerization catalyst comprising . The interpolymerization may be carried out at an azonitrile and in the absence of substantial any temperature short of the decomposition point amounts of hydroxyl-containing compounds. of the chemicals involved. The lower tempera 10. A polymeric addition product of a poly ture limit is that at which the reaction becomes merizable organic compound containing conju impractically slow. Temperatures from -10° to gated olefinic double bonds and a mono-Substi 125° C. may be used, the preferred range ordi 35. tuted dihalophosphine having the formula RPX2 narily being from room temperature to about 75 in which R, represents a member of the group C. Within this range, no “ceiling effect' has been consisting of alkyl, aryl and aralkyl radicals and observed, i.e., there appears to be no temperature X represents a member of the group consisting at which the rate of depolymerization balances of chlorine and bromine, said addition product or exceeds the rate of polymerization. The reac containing at least 0.1% chemically bound phos tion will usually be carried out at atmospheric phorus. pressure, although higher or lower pressures may 1. The polymeric addition product of claim 10 be used. in Which the polymerizable organic compound is I claim: selected from the group consisting of butadiene, 1. The process of preparing a phosphorus isoprene, 2-chloro-1,3-butadiene and 2-bromo containing polymeric addition product which 1,3-butadiene. comprises contacting a polymerizable organic 12. A polymeric addition product of butadiene compound containing conjugated olefinic double and dichlorophenylphosphine, said addition prod bonds with a mono-substituted dihalophosphine uct containing at least 0.1% chemically bound having the formula, RPX2 in which R, represents 50 phosphorus. a member of the group consisting of alkyl, aryl 13. A polymeric addition product of isoprene and aralkyl radicals and X represents a member and dichlorophenylphosphine, said addition prod of the group consisting of chlorine and bromine, uct containing at least 0.1% chemically bound in the presence of a free radicai polymerization phosphorus. catalyst and in the absence of substantial amounts i4. A polymeric addition product of 2-chloro of hydroxyl-containing compounds. 1,3-butadiene and dichlorophenylphosphine, said 2. The process of preparing a phosphorus addition product containing at least 0.1% chemi containing polymeric addition product which cally bound phosphorus. comprises contacting a polymerizable organic WILLIAM B. McCORMACK. compound containing conjugated olefinic double 60 bonds with a mono-substituted dihalophosphine having the formula RFX in which R, represents References Cited in the file of this patent a member of the group consisting of alkyl, aryl UNITED STATES PATENTS and aralkyl radicals and X represents a member Number Nare Date of the group consisting of chlorine and bromine, 2,382,812 Parker ------Aug. 14, 1945 in the presence of chloroform and a free radical 2,520,601 Lee ------Aug. 29, 1950 polymerization catalyst and in the absence of sub stantial amounts of hydroxyl-containing con pounds.