Patented Mar. 13, 1934 1950,431 UNITED STATES PATENT OFFICE 1,950,431 HALOGEN DERVATIVE OF ACETYLENE SAEPOLYMERS AND PROCESS FOR MAKING Wallace H. Carothers and Arnold M. Collins, Wilmington, Del, assignors to E. I. du Pont de Nemours & Company, Wilmington, Del, a cor poration of Delaware No Drawing. Application October 22, 1930, Seria No. 490,538 34 Claims. (C. 260-62) This invention relates to a new class of Organic compounds and the method of their preparation. Chloro-2-butadiene-1,3 (and dichlorobutene) More particularly, it relates to compounds obtaine This compound is readily prepared by causing able from monovinylacetylene by causing it to nonovinylacetylene to combine with hydrogen 5 combine with a hydrogen halide. chloride. This combination may be effected un 6) Monovinylacetylene was first discovered by der a great variety of conditions and in the Willstatter and Wirth (Berichte, 46, 535) and complete absence of an added catalyst but it is prepared by exhaustive methylation of 1,4-tetra favorably controlled and accelerated by certain methyl-diaminobutene-2. More recently, an catalysts such as the metal halides. Among 0 in proved proceSS of preparation has been dis twenty-four metal chlorides tested may be men 65 covered by Nieuwland who (see his application tioned mercuric, mercurous, magnesium, cal Serial No. 305,866 filed September 13, 1928) re cium, auric, and cuprous chlorides which are acts acetylene in the presence of S, cuprous cata increasingly effective in the order named. The lyst and a nitrogen base to obtain a mixture of course of the reaction is also favorably affected 25 acetylene polymers containing monovinylacet by the presence of ammonium chloride or a sub 69 ylene which may be separated by distillation. stituted ammonium chloride, exemplified by We have discovered that inchovinylacetylene, pyridinium chloride and methyl ammonium When mixed with a hydrogen halide, will react chloride. The annonium chloride or substitut to yield products not heretofore known, and have ed annonium chloride anay be added as such 25 isolated and identified these novel productS. he to the acid reaction mixture or alternatively may compounds obtained by this process from non be formed in situ by the addition of a suitable ovinylacetylene comprise the 2-substituted-1,3- annonia, compound. She results are essential butadienes having the formula, CH2=C(X)- ly the Same without the ammonium chloride, CH=CH2 wherein X represents a halogen aton. however, as it merely slightly increases the yield 25 These compounds may be characterized or de of chloro-2-butadiene-13. 8) scriptive purposes as cz-vinyl vinyi esters of the Our present preferred method of preparing hydrohalogen acids or as 3-butadienyl halides. chloro-2-butadiene-1,3 consists in shaking or They are analogs of isoprene having in their Stirring monovinylacetylene with a concentrated molecules, in place of the methyl group, halogen acqueous Solution of hydrogen chloride contain SC atoms, and they may ice assigned the names ing cuprous chloride and ammonium chloride. 83 fluoroprene, chloroprene, oromoprene and iodo This method is illustrated by the following ex prene, or collectively haloprenes. annple, - Other hydrohalogen addition products of icample -Fifty grains of cold monovinyl acetylene is placed in a pressure bottle contain 35 monovinylacetylene are also produced by the ing a, thoroughly chilled mixture composed of process of the present invention and in announts 175 g. of concentrated hydrochloric acid (sp. gr. 9. varying with the conditions and reagents en i.19), 25 g. of cuprous chloride, and 10 g. of am ployed as will be explained inore fully below. nonium chloride. The bottle is closed and The exact structure of these compounds have shaken until the heat of reaction causes its tem 40 not all been determined, but anong them are perature to rise to about 30° C. This usually 93 compounds having the general formula: requires about 10 minutes. It is then thoroughly (i) CH-CH=C=CH2, wherein S is a halogen cooled by immersing it in iced water (10-15 min atom, represented by chloro-4-butadiene-2 and utes). It is then removed from the cooling batha also the dihalogen buttenes. Such as dichlorobus and shaken for three hours. The monovinyl 25 tene and dibromobutene. These dihalogen acetylene is now almost completely converted products are formed as byproducts in the prep into chloro-2-butadiene-1,3 and dichlorobutene, aration of chloro-and bromo-2-butaliene-1,3. The contents of the bottle are poured into a Although their structure has not been positively Separatory funnel and the dark aqueous layer is established, there is little doubt that they are drawn off from the supernatant liquid. The lat One of the two compounds 1,2-dihalogen-butene-2 tei is washed with saturated aqueous sodium 05 (X) Cia-CX=CH-CH3 or 2,3-dihalogen-bu chloride solution and separated. A small amount tene-2 (CH3-CX=CH-CH2X). of hydroquinone, catechol, or pyrogallol is add The preparation of compounds of the type dis ed to it, and it is dried with anhydrous sodium 55 cussed above is described in full below. Sulfate or calcium chloride. It is then filtered into a distilling flask containing a small amount 140 2 1950,481 of hydroquinone, catechol, or pyrogallol and dis into a container. In order to maintain the prop tilled. A very small amount of distillate boil er proportions, hydrogen chloride is continuously ing at 35-55 C. is frequently obtained. This is introduced, either in admixture with the gaseous a mixture of chloro-2-butadiene-1,3 and mOno monovinylacetylene or as a separate stream. vinylacetylene. It may be separated into its We have also carried out the combination of components by redistillation. The main frac-.. aqueous hydrochloric acid with monovinylacety tion boils at 55 to 75° C. It is substantially pure lene in the presence of cuprous chloride in a jack chloro-2-butadiene-1,3. A higher fraction boils eted autoclave provided with a stirrer. In using ing at 75-135° C. is chiefly dichlorobutene-2. It this method it has been found advantageous to may be purified further by redistillation, In an add the hydrochloric acid-cuprous chloride mix O actual test 1000 g. of monovinylacetylene (in 20 ture to the monovinylacetylene and to keep the bottles) gave 1560 g. of reaction product which temperature of the reaction mixture in the neigh on distillation gave a few drops of 35-55 C. borhood of 25°C. fraction, 1150 g. of 55-75 C. fraction, 200 g. of AS appears from the above discussion, chloro 75-135° C. fraction. - 2-butadiene-13 is formed by the action of 5 The chloro-2-butadiene-1,3 (55-75 C.) frac aqueous hydrochloric acid on monovinylacetylene tion may be purified further by redistillation to either in the presence or absence of a metallic obtain substantially pure chloro-2-butadiene-1,3 chloride catalyst. It has been found that hy boiling at about 61 C. For this purpose We drogen chloride also combines with monovinyl- 5 prefer to use a flask provided with a fraction acetylene in Solution, such, for example, as an 9. 20 ating column and to carry out the distillation ethereal solution both in the presence and ab under diminished pressure (100-500 mm.) and in sence of a catalyst. a current of inert gaS Such as carbon dioxide or Chloro-2-butadiene-1,3 may be described as a nitrogen. colorless, mobile liquid having a characteristic Various factors in the above process may of odor somewhat resembling that of ethyl bromide, 100 25 course be modified Or changed without affecting insoluble in water and miscible with the common the essential result, the formation of chloro-2- Organic Solvents. It has a boiling point of about butadiene-1,3 and dichlorobutene. Thus, in 61 C. at 760 mm. pressure, a density at 20° C. of stead of separating the crude reaction product about 0.957-8 and a refractive index of 1.458. It from the reaction mixture by mechanical means polymerizes spontaneously and very rapidly to 105 30 the separation may be effected by steam distill form an exceedingly strong, tough, transparent, ing the entire reaction mixture. The reaction elastic mass resembling natural rubber. This may be run at higher Or lower temperatures. The polymerization may be inhibited, however, by the concentration or the amount of the hydrochloric addition of certain anti-catalysts as already men acid may also be increased or diminished al tioned above. O 35 though the preferred range of concentration lies Dichlorobutene, formed as a byproduct in the above 15% by weight of HCl based on the Water preparation of chloro-2-butadiene-1,3 is a color present in the mixture. However, the pressure less liquid having a boiling point of 128° C. at at which the reaction is carried out will of course 760 mm. and at 20° C. a specific gravity of 1.161. influence the concentration of acid desirable. and a refractive index of 1.479. It is insoluble 15 40 The concentration and the nature of the catalyst in water and miscible with most organic solvents may also be changed. and is stable, showing no tendency to polymerize The ratios of unchanged monovinylacetylene, aS does chloro-2-butadiene-1,3. chloro-2-butadiene-1,3 and dichlorobutene-2 in the product are, however, considerably affected Chloro-4-butadiene-1,2 120 45 by changes in some of these factors. Thus, by As already indicated, hydrogen chloride in con increasing the amount and concentration of the Centrated aqueous solution combines with mono hydrochloric acid the proportion of dichlorobu vinylacetylene fairly rapidly, even when no tene may be greatly increased. If the cuprous catalyst is present, to form chloro-2-butadiene chloride catalyst is Omitted, Or if a less powerful 13. When cuprous chloride is used as a catalyst 125 50 catalyst is used, considerable amounts of an iso the reaction is greatly accelerated and the prod mer of chloro-2-butadiene-13 are formed as de lucts formed are largely chloro-2-butadiene-1,3 scribed more fully below. The particular Set of and dichlorobutene-2, and the latter results from conditions described above, however, has given the addition of hydrogen chloride to the chloro the largest yield of chloro-2-butadiene-13. 2-butadiene-1,3. But when no catalyst is em- 130 55 The addition of an antioxidant Such as hy ployed or when the less effective catalysts are droquinone, catechol, or pyrogallol to the crude employed an isomeric compound chloro-4-buta chloro-2-butadiene-1,3 before distillation is an diene-1,2 is formed in increasing amounts. Thus, important feature of the above process. These by the selection of a suitable catalyst the isomeric materials, and such materials as trinitrobenzene, Compound can be made the major product. In an - a 60 iodine, diphenyl guanidine and m-tolyulenedi-. experiment in which calcium chloride was used amine, inhibit the loss of chloro-2-butadiene-1,3 as a catalyst only 23% of the distillable product by polymerization during the drying and distilla WaS composed of chloro-2-butadiene-13 while tion. Other antioxidants may be used for this 61% was composed of the isomeric compound purpose, but these have been selected from a long chloro-4-butadiene-1,2; and the dihydrochloride 4 65 list of tested materials as among the most effec present Was contained in a mixture from which tive. no individual could be separated. The use of The combination of monovinylacetylene and calcium chloride to increase the yield of chloro-4- hydrogen chloride may also be effected in contin butadiene-1,2 is illustrated by the following ex uous fashion by filling a vessel with a catalyst ample: ...) 70 Solution of the type described in Example I and Eacample II-In each of 20 bottles were placed introducing the monovinylacetylene in gaseous 175 g. of concentrated hydrochloric acid, 25 g. form infine bubbles. The resulting crude chloro of calcium chloride and 50 g. of monovinyl 2-butadiene-13 rises to the surface of the solu acetylene. The bottles were closed and shaken 5 tion where it is collected or allowed to Overflow continuously for 5 hours, the supernatant oily to 1950,481 3 layers were drawn off and combined, washed with to transparent strong tough elastic masses. The water, stabilized with pyrogallol, dried with an course of their polymerization is Susceptible to hydrous calcium chloride, and distilled through control by suitable regulation of the conditions a long column. The fractions collected were: under which it is allowed to occur, so that one (1) 74 g. at 30-55° C., (2) 222 g. at 50-75 C., may obtain at will polymeric mixtures of diverse 80 (3) 576 g. at 80-95 C., (4) . 77 g. at 95-120° C. kinds such as, for example, readily distillable (5) 123 g., residue. Fraction (2) was chiefly odorous liquids, thick transparent jellies, sticky chloro-2-butadiene-3. Fraction (3) was chiefly adhesive elastic bodies, and very hard strong chloro-4-butadiene-1,2.. On redistillation it tough masses. Moreover, the compounds of this 10 yielded 446 g. of pure product. class exhibit a high degree of reactivity toward a 85 This compound has a boiling point of 86-88 variety of chemical reagents, and they may be C., a refractive index of about 1.475 at 20° C. and converted into many useful and valuable prod specific gravity of about 0.991. ucts by reactions not involving polymerization. These modifications are, however, not the Sub 5 Bromo-2-butadiene-1,3 (and dibromobutene) ject of the present invention which relates to 90 A preferred method for the preparation of this the products as originally obtained and their compound is illustrated by the following example. , preparation. 2. The process, as will be seen, is in general analo We claim: gous to the preparation of the corresponding 1. An addition product obtainable by reacting 20 chloro-product. The same catalysts and general monovinylacetylene and a hydrogen halide. 95 methods may be used and the observations made 2. A product having the formula in connection with the preparation of the corre sponding chlorine product, as to possible varia tions in the preferred conditions and catalysts, wherein X represents chlorine or bromine. 25 apply. 3. An addition product obtainable by reacting 10) Eaccingle III.-Fifty two grams of monovinyl Onovinylacetylene and hydrochloric acid. acetylene is placed in a pressure bottle together 4. As a new product, a colorless Knobile liquid, with 85 cc. of concentrated hydrobronic acid insoluble in Water, miscible with organic solvents (approximately i normal) and 35 g. Of cuprous boiling at about 61 C. at 760 mm. pressure and 30 bromide, and the bottle is closed and shaken having the formula 05 vigorously for 6 hours or longer. The aqueous solution is then separated from the oily layer CH2=CC1-CH=CH and the latter is washed with water, stabilized said product being substantially free of ina With catechol, and distilled preferably under di purities. 35 minished pressure is 8, current of nitrogen or 5. A product having the formula, carbon dioxide. The fractions collected are; brono-2-butadiene-13 boiling at 38-40 C. at CCH-CH=C=CH2 155-165 mra. (about 32 g.), and dibronobutene 6. A product, having the formula: boiling at 88-92 C. at 56-60 in a... (about 48 g.). Each of these fractions may be purified further CH2=CC-CH=CH2 11.5 by redistilation. 7. Tiae process of preparing a new product Bromo-2-butadieae-33 polymerizes somewhat Which co-prises reacting a hydrogen halide with imore slowly tha: chloro-2-butadiene-3. The Inohovinylacetylene, the halide being present in pally inerization is held back by Such materials as Such concentration as to form an addition con Solvents, catecho, pyrogallol, etc. It has a boils pourd. 2) ing point of iroi; 42-43 C. at 165 mi., pressure, 3. The process of clairn wherein the reaction density of about .402 at 20° C. and 8, refractive is carried out in the presence of a reaction cata index of about .50. lyst containing a metal ion of the group consist libronobuiene, formed as a, byproduct in Rhs ing of Caprols, auric, calciuri, Inagnesium, ner preparation of promo-2-butadiene-3 as de crous and XYnei'cutic ions. 25 scribed above, as 8, boiling goint of iOS 56-59 9. The process of preparing a new product C. at 6 inn. pressure, a refractive ix.dex of about which congrises reacting a hydrogen halide of i.554 at 20° C. and a specific gravity of acou; the group consisting of HC and HBr with mono .868. 5 vinylacetylene, he hydrogen halide being pres 5 Obviously, brono-4-butadiene-1,2 grazy a sprea era; in Sulcia Coracentration as to for in an addition 3G) pared by nethods analogous to those disclosed CO2 pound. for the preparation of the corresponding cocoa 10. The process of claim 9 wherein substantial corpound. y conce atiated acid is employed in the presence As will be evident from the above, We have dise of a retal halide of the group consisting of the 80 covered a new class of compounds comprising the cuprous, auric, calciuxin, magnesiu Xin, nercurous hydrohalogen addition products of monovinyl. and Saei"caric chlorides and Oromides. acetylene and developed simple and practical 1. Ethe grocess of preparing new products methods of naking the same by treating nono which corprises reacting nonovinylacetylene vinylacetylene with hydrochloric or hydroloronic With 8, concentrated Solution of a hydrogen halide acid. Hydrofluoric acid also reacts vigorously of the group consisting of H3 and HCl in the 4. with nonovinylacetylene. presence of a Eiheta halide of the group consist No compounds of the class herein disclosed ing of the crous, auric, calciura, Anagnesium, have hitherto been described, nor have any iease mercuros and aercuric chlorides and oronides, ible methods for their preparation been knoW. and &r 22 in R2Onitar Compound of the group con We have identified, and studied representatives sisting of a Enriconium chloride and the substituted 45 of this novel class and have found that they pos annoni) in chlorides and bronides. sess unusual and valuable properties. his is 2. The grocess of preparing a new product especially true of the two halogen 1,3 butadienes which comprises reacting on nonovinylacetylene which are distinguished by the extraordinary with hydrochloric acid to form an addition prod ease and spontainiety with which they polymerize lict acad Se233 ating from the reaction gaixture St) 4. fractions boiling respectively at substantially 61 22. An addition product obtaied by reacting C., 87° C. and 128 C. an open chain acetylene polymer and hydrogen 13. The process of preparing new products chloride, said product being in concentrated form. which comprises reacting on monovinylacetylene 23. An addition product obtained by reacting with concentrated hydrochloric acid in the pres monovinylacetylene and hydrochloric acid, said 80 ence of a metal halide of the group consisting product being in concentrated form. of auric, calcium, magnesium, mercurous and 24. As a new product, a monochlorobutadiene. mercuric halides, adding an antioxidant of the 25. An addition product obtainable by reacting group consisting of hydroquinone, catechol and monovinylacetylene and hydrogen bromide. . pyrogallol and separating from the product frac 26. As a new product, bromo-2-butadienes13. tions boiling respectively at substantially 61 C., 27. The process which comprises reacting an 87° C. and 128 C. open chain acetylene polymer with a hydrogen 14. The process of preparing a new product halide. - which comprises reacting on monovinylacetylene 28. The process which comprises reacting with concentrated hydrochloric acid in the pres monovinylacetylene with hydrogen chloride. 90 s ence of cuprous chloride and separating from the 29. The process of claim 28 in which the re product fractions boiling respectively at Substan action is carried out in the presence of a solvent tially 61° C. and 128 C. for the monovinylacetylene. 15. The process of preparing new products 30. The process which comprises reacting an which comprises reacting on monovinylacetylene open chain acetylene polymer with a hydrogen 95 With concentrated hydrochloric acid in the pres halide in the presence of a catalyst for the re ence of cuprous chloride and ammonium chloride action. adding an antioxidant and separating from the 31. The process of preparing new products product fractions boiling respectively at sub which comprises reacting monovinylacetylene stantially 61° C. and 128° C. With a concentrated Solution of a hydrogen halide 100 16. The process of claim 13 wherein 175 grams of the group consisting of HBr and HCl in the of hydrochloric acid (sp. gr. 1.19) are reacted at presence of a metal halide of the group consisting about 30° C. with substantially 50 grams of mono of the cuprous, auric, calcium, magnesium, mer vinylacetylene in the presence of Substantially curous and mercuric chlorides and bromides, and 10 grams of ammonium chloride and 25 grams an ammonium compound of the group consisting 05 SO of cuprous chloride. of ammonium halides and substituted am 17. The process of preparing new products monium halides. - which comprises reacting monovinylacetylene 32. An addition product of monovinylacetylene with concentrated HBr and separating from the and a hydrogen halide having the formula product fractions boiling at 38-40 C. at 155-165 110 SS mm, and 88-92 C. at 55-60 mm. respectively. XCH-CH=C-CH 18. The process of claim 17 wherein 185 grams wherein X represents either chlorine or bromine. of hydrobromic acid (approximately 11 normal) 33. A product obtainable by reacting a hydro are reacted with substantially 52 grams of mono gen halide of the group consisting of HCl and vinylacetylene in the presence of substantially HBr with monovinylacetylene to form an addi 115 40 35 grams of cuprous bromide. tion compound, Said product having the empiri 19. An addition product obtainable by reacting cal formula, an open chain acetylene polymer and a hydrogen halide and containing not over tWO halogen atoms. C4H4(HX) in 20. An addition product obtainable by reacting where X is chlorine or bromine and n is 1 or 2. 120 4. an open chain acetylene polymer and hydrogen 34. A process for making 2-chlorobutadiene-1,3 chloride and containing not over two chlorine which comprises reacting vinyl acetylene with atoms. hydrogen chloride in the presence of a catalyst 21. An addition product obtained by reacting consisting essentially of cuprous chloride. an open chain acetylene polymer and a hydrogen WALLACE. H. CAROTHERS. 125 50 halide, said product being in concentrated form. ARNOLD M. COLLINS.

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