[1]Utu"ted States Patent Office 31420,904 3,420,904 PROCESS FOR OLIGOMERIZING A CONJUGATED ALIPHATIC DIOLEFLN AND ETHYLENE Langley R. Hellwig, Trenton, N.J., assignor to Columbian Carbon Company, New York, N.Y., a corporation of Delaware No Drawing. Filed May 23, 1966, Ser. No. 551,943 U.S. Cl. 260-666 21 Claims Int. Cl. C07c 3120; C07f 15104 ABSTRACT OF THE DISCLOSURE, Processes are described for the oligomerization of a conjugated aliphatic diolefin by contacting a liquid admixture of the diolefin and ethylene with a nickel coordination catalyst. Illustrations show the formation of 1,5-cyclodecadiene and 1,4,9-decatriene from a liquid admixture of 1,3-butadiene and ethylene in the presence of either a preformed Lewis base complex of nickel (0) or such complex which is formed in situ by reducing a nickel compound in the presence of a molecular Lewjis base. Numerous processes for the homo-oligomerization of conjugated aliphatic diolefins, such as 1,3-butadiene, have been described in the prior art. These known processes include an essentially thermal process, as well as a variety of catalytic processes which utilize a Group Viii metal coordination catalyst. These processes are applicable to the cyclic dimerization, trimerization, or tetramerization of a conjugated diolefin, such as 1,3-butadiene or a substituted butadiene, to yield, as the predominant product, a cycloolefin or a mixture of cycloolefins having from six to about twenty cyclic carbon atoms. Among the products recovered and identified from such reactions are vinyl cyclohexene, cyclooctadiene, cyclododecatrien.e and cyclohexadecatetraene. Particularly, suitable coordination catalysts that have been described in the prior art are nickel complexes with carbon monoxide or a molecular organic Lewis base in which the formal valence of nickel is less than that of nickel in its lowest normal oxidation state; i.e. less than +2. Typical of such complexes are the nickel (0) carbonyls and complexes of nickel (0) with hi,-her cycloaliphatic multiolefins, such as cyclododecatriene, or esters of trivalent Group V-A elements having an atomic weight of from about 30 to abotit 209. Such complexes have been utilized either alone, as in United States Patents 3,004,081, 3,187,062 and 3,243,468, or in combination with a reducing agent, as in U.S. Patents 3,247,270 and 3,249,641. In addition, compositions containin.- nickel complexes which are suitable for oligomerizing 1,3-butadiene have been produced by the reduction of various nickel (II) and nickel (III) compounds in the presence of aminp-s, esters or trivalent phosphorus, arsenic or antimony, or aliphatic multiolefins, such as cyclopentadiene, cyclooctadiene and cyclododecatriene, as well as 1,3-butadiene itself. The preparation of such suitable nickel complexes from compounds in which nickel is present in a normal oxidation state is shown in U.S. applications S.N. 202,406 and S.N. 129,968. Althou.-h the nickel coordination catalysts described in the prior art are well known and have been used for many years in the production of cycloolefins containing 6, 8 a nd 12 cyclic carbon atoms, all attempts to utilize these catalysts to produce a 10 member ring by the homooligomerization of a conjugated alipbatic diolefin have been unsuccessful. It is an object of this invention to provide a simple process for prodticing cooligomers of a conjugated aliphatic diolefin and ethylene. It is a further object of this Patented Jan. 7, 1969 2 invention to provide a process for effecting the cooligomerization of two moles of a conjugated aliphatic diolefin with one mole of ethylene. SLill another object of this invention is to provide a means for producing cyclic diolefins containing 10 cyclic carbon atoms and acyclic triolefins. A more specific object of this invention is to provide a process for effecting the cooligomerization of two moles of 1,3-butadiene and one mole of ethylene to produce 1,5-cyclodecadiene, which can readily be hydrogenated and then oxidized to sebacie acid in accordance with known procedures. Further objects will be apparent to those skilled in the art from a consideration of the followin@ description of this invention. It has now been found that, under the conditions set 15 forth below in detail, a conjugated aliphatic diolefin, such as 1,3-butadiene, can be cooligomerized with ethylene by contacting a liquid admixture of these monomers with one or more of the Group VIII metal coordination catalysts which are taught by the prior art to be effective in catalyz20 in@, the homooligomerization of butadiene. As in the case of butadiene homooligomerization, the preferred catalysts for use in the process of the instant invention are the nickel complexes with carbon monoxide or a molecular organic Lewis base in which the formal valence of nickel 25 is less than +2, and preferably 0. Althou,-h the precise mechanism involved in the catalytic homooligomerization of conjugated aliphatic diolefins has not been precisely determined, it has been proposed that the active catalyst species in all the prior art 30 systems is a transitory complex of the conjugated aliphatic diolefin and zero valent nickel. It further has been suggested that such complexes result either from the displacement by the conjugated aliphatic diolefin of other Lewis bases that are coordinatively bonded to nickel (0) or 35 from the coordination of such conjugated diolefin with nickel which has been activated by a reduction of the valence state to a valence of less than +2. It has further been postulated that the presence of Lewis acid reducing agent, which is a stronger electron acceptor than nickel, 40 facilitates such replacement or complexing by itself complexing preferentially with such other Lewis bases, including anions, which may be present in the system, thereby reducing their affinity for nickel. Although the invention set forth herein is not to be interpreted in light of this theory, 45 it is quite useful in explaining the similar results obtained by the use of apparently dissimilar nickel sources in the instant cooligomerization reactions, as well as in the prior art homooli@omerizations. In addition, this theory offers a pragmatic explanation for the observed fact that the 50 addition of a Lewis acid reducing agent has little effect with certain nickel sources and is essential for the practical utilization of others. For example, the addition of a Lewis acid reducing agent to a nickel (0) complex having ligands which are easily replaced by butadiene, such :acs 5 5 bis (cyclooctadiene) nickel or tetrakis (triphenylphosphite) nickel, has little, if any, effect on the reaction rate or product selectivity. On the other hand, in the absence of a Ziegler type activator, low temperature homooligomerization or cooli,@omerization of butadiene proceeds at 60 a low rate with a nickel (0) complex in which the li-ands are tightly bound, and does not occur at all whe'n the nickel has a formal valence of +2 or +3, as in bis (triphenylphosphine) nickel dibromide or (tetraphenyleyelobutadiene) nickel dibromide. 65 Although the process of the instant invention is similar in many respects to the homooligomerization processes of the prior art, it has been fourid that the presence of both monomers in a liquid or fluid phase in the reaction system 70 is essential for si.-nificant yields of cooli.aomer prodtict. For example, when a inixture of 1,3-butadiene and ethylene in a molar ratio of 2: 1 is bubbled through a toluene solution of
[2]3)420)904 3 a nickel coordination complex, such as bis (triphenyl arsir,e) nickel d,'.Carbonyl, at a temperature of 100' C. at atmospheric pressure, tinreacted ethylene can be recovered almost quintitatively and the oligomer product is essentially the same as that which would be obtained in the absence of ethyene. On the other hand, when this reaction is conducted tinder a pressure of 400 p.s.i.g., ethylene solubility in the liquid benezer@e/butadiene solutio-ii is significantly increased, thereby facilitating the production of cooligomers. Many of the advanta.es of the instant process can be realized by operating with a solvent under slightly elevated pressures which, although insufficient to liquify the diolefin, increases the solubilitydf gaseous diolefin and ethylene in the solvent; however, it has been found that, under such moderate pressures, a lar.-e excess of the more reactive diolefin is present in the liqiiid phase, thereby favoring the formation of homooligomers. A preferred embodiment of this invention. involves the use of pressures sufficiently high to liquify a portion of the diolefin component. Under such circumstances, the ethylene solubility in the liquid phase (diolefin or diolefin and solvent) is greatly increased, as is the yield of cooli.-cmer. The minimum total pressure necessary to liqliify a portioil of the diolefin component at a given temperature is, of course, a value which continuouslv changes with the variations in concentration of the materials inche reaction system which exert a significant partial presstire; including both monomers, reaction products and such inert solvents and gases as may be present. In general, the preferred mode of operation can be achieved by conducting the cli.-omerization undar a total pressure that is in excess of the vapor pressure of the pure diolefin at reactio@i temperature. When 1,3-butadiene is used as the diolefin component in a reaction conducted in benzene at very low tenil)eratures. for exaniple 15' C., the ethylene concentration in the llqtiid phase increases si.-nific-,mtly as the reactor pressure is raised above about 30 p.s.i.a. Similar effects can be noted at reaction temperatures of 40' C. and 80' C. as the pressure is raised above about 65 p.s.i.a. and about 150 p.s.i.a., respectii,ely. High concentrations of ethylene in the liquid phase andoutstandin,@ results can be obtaiiied by utilizing total reactor pressures which are at least aboi-it 30 p.s.i. and preferably at least about 100 p.s.i. higher than the vapor pressure of the pure diolefin. The reaction of the instant invention can be conducted over wide temperature range. Cooli.-omers o:f butadien e and ethylene may be obtained at tenioeratlires below O' C. and above 150' C.; however, it is seldom necessar y o,r desirable to utilize temperatures otitside a preferre d ran-e of from about 30' C. to about 130' C. Reaction s at temperatures below this ran,-e are generally quite slow, while those coiducted above this range may exceed the pseudo critical temperature of the reaction mixture and thereby diminish the yield of the desired cooligomer product. An especially preferred operating range is from about 40' C. to about 100 C. at pressures froni aboi-it 100 p.s.i.a to about 2000 p.s.i.a. or higher and preferably from about 300 p.s.i.a. to about 700 p.s.i.a. In general, operating temperatures below about 80' C. favor the formation of cyclic diene cooligomers containing 10 c3rclic carbon atoms, whereas teniperatures above about 80' C. tend to yield a cooligomer product that predominates in acyclic multiolefinic cooligomers. Prolon,-Cd exposure of the cyclodecadiene products, and particularly 1,5-cyclodecadiene, to temperatures above aboiit 80' C. also leads to ring collapse whereby thesecooligomers are converted to divinylcyclohexanes. The conjugated aliphatic diolefins that are useful in the process of this invention are 1,3- butadiene and hydrocarbyl or halogenated derivatives thereof which contain up to nine carbon atoms, and preferablyfrom folir to six carbon atoms. Examples of such diole@lins include 1,3- butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 4-methyl-1,3-hexidiene, 2,4-octadiene. 2- chloro-1,3-butadiene and 2,3-dichlorg-1,3-butadiene. The 4 preferred diolefins are 1,3-bLItadiene and 2-methyl-1,3butadiene (isoprene). The nickel (0) coordination complexes which may be used in the process of this invention are compositions in which nickel, having a formal valence of less than 2 and preferably 0, is coordinatively bo@ided to one or more molecules of caroon monoxide or an organic Lewis base (electron pair dopor); i.e. an organic molecule having at least one pair of electrons available for shar:,.-ig with 10 nickel. Such organic Lewis base molecules are well knoivn and include organic derivatives of trivalent GroLip V-A elements, as well as ethylenically and acetylenically unsaturated hydrocarbons. Typical of such moleci-iles are the amines, stich as tri15 methylamine, triphenylamiiie and pyrrolidine; triorgano derivatives of phosphorus, such as triphenyl phosphine and tri(2-ethylhexyl) phosphite; analo,-Ous organo compounds of arsenic, antimony and bismtith, such as, triphenyl iarsine and triphenvl antimonite; and cyclic multi20 olefins, such as, cyclopentadiene, cyclooctadiene, cyclodecadiene and cyclododecatriene. A preferred class of nickel coordination complexes that are tiseful in the process of the instant invention includes those complexes which are stable at room temperature 25 and atmospheric pressure and can therefore be readily introduced into the reaction system as discrete conipositions. The use of such stable complexes obviates the necessity for pressure stora,,,-e vessels and facilitates close control of the co-iicentration of complex nickel in the re30 action system. The preferred complexes of this group cin be represented by the empirical formula (L).Ni(CO)4-n wherein L is an ester of a trivalent Group V-A element 35 havin.- an atomic weight of from about 30 to about 209, preferably from aboiit 30 to aboi-it 122, and n is an integer from 0 to 4 inclusive. Representative complexes of this group are nickel tetracarbo,-iyl, triphenyl phosphite nickel tricarbonyl, triethyl phosphine nickel tricarbonyl, 4o bis(triphenyl phosphite) nickel dicarbonyl, bis(triphenyl arsine) nickel dicarbonyl, bis(tricycIGhexyl antimoijite) nickel dicarbonyl, tris(tripheiiyl phosphite) nickel carbonyl, tris(triphenyl phosphine) nickel carbonyl, tetrakis (triphenyl phosphite) nickel, bis (tripberiyl phosphite)- 45 bis(triethyl phosphite) nickel, tetrakis [tri(4-methyl phenyl) phosdhitel nickel, tris [tri(2-metboxyethyl) phosphitc_l nijkel carbonyl, [tri(4-chloro phenyl)phosphite] nickel tricarbonyl, bis [tri(4-ethoxy phenyl)phosphitel-bis rtri(2-ethoxy ethyl) phosphitel nickel and 50 tris [tri(4-chloro phenyl) phosphitel nickel carbonyl. An especially preferred class of nickel complexes is exemplified by the nickel carbonyls complexes of the preceding empirical formula in which the electron donor molecule L is a trialkyl or triaryl ester of phosphorus, arsenic or 55 antimony in which each hydrocarbyl group c-ontains from I to about 10 carbon atoms. The nickel coordination complexes of t@,is inventio@i may @be used alone or iii combination and are often advantageously employed in the presence of an activator 6o selected from the group consistin.- of metals of Groul)s I-A, II-A, II-B, 111-A and IV-A, as well as hydride and or-ano metallic compotinds of said metals. Amon.the metals useful as activators accordin,@ to this invention are lithium, soditim, potassitim, beryllium, ma-- 65 nesium, calcium, strontium, barium, zinc, cadmium, mercurv aluminum, gallium, indium, germanium. tin and lead. i@presentative hydride and organo metallic compoi-inds of these suitable m-,tals include lithium hydride, sodiun-i hydride, calcium hydride, aluminum hydride, ;i70 'b@tyl litbium, allyl sodium, phenyl sodium, diethyl calcium, tetraethyl lead, trimethyl aluminum, diethyl aluminurrt hydride, ethyl aluminum dichloride, and phenyl magnesiuin bromide. A preferred -roup of activators is i-epi-esented -by alLi@nlinL[M compoLind,,,, @oll the foi-iiiult 75 (R) AI-A
[3]3)420,904 5 wherein R is a hydrocarbyl group having up to a@bo-at 20 car-bon atoms and A is selected from the group, consisting of R, H, chloride and lower hydrocarboxy radicals. Example,s of such preferred compounds include triphenylaluminiim, tri(polyethylene) aluminum compounds, ethoxy diethyl aluminum, diethyl aluminum hydride and diethyl aluminum chloride. Trialkyl aluminiim compounds such as triethyl aluminum and triisobutyl alumintim represent an especially preferred group of activators. When these activators are used in the process of this invention, they can be employed in a molar ratio of activator metal to nickel from as high as 50 to 1 to@ as low as 0.1 to 1. It is usually desirable, however, to employ them in a molar ratio of ,ictivator to nickel,of from about 25 to 1 to about 0.25 to 1, and particularly, from abo,,it 12 to 1 to about 1 to 1. Althou.-h the addition of a pure stable nickel (0) coor,dination catalyst to the reaction system minimizes process equipment requirements and offers other advantages as described above, greater economy of operation can often 'be :achieved in the process of this invention, as in t-he prior art conjugated diene homooli-omerization reactions, by utilizin- a suitable nickel complex in impure form, slich as in admixture with by-products and unreacted components of its synthesis. Suitable synthesis mixtures of this type can be prepared by a variety of we'il known procedures, as exemplified by U.S. Patent 3,152,158 @and U.S. applications S.N. 129,968 and S.N. 202,406, tbe,diselosures of which are incorporated herein by reference. Illustration of such procedures is the ptoduction of a synthesis mixture of tetrakis (tri@ydrocarbylphosphite) nickel as disclosed in U.S. Patent 3,152,158 i.e. by the interaction of a molar excess of trihydrocarbyl -phosphite with an organo nickel compound (a compound havin.- a carbon to nickel bond) such as bis(cyclopentadienyl) nickel picrate, bis(indenyl) nirkel or bis(cyclooetadiene) nickel. Another known method of prodlicing suitable synthesis mixtures is,by the interaction, either in situ in the reaction system or externally, of a readily available and relatively inexpensive nickel (11) or nie-kel (IH) compound witli a reducin.- a,-ent and a molecular organic Lewis base, as illustrated by United States applications S.N. 129,968 and S.N. 202,406. Employment of the reaction products of this general method offers an additional advantage in that it facilitates the use in the cooli,@omerization reaction of this invention o@f nickel coordination complexes with any molecular organic Lewis base (as descri,bed above) include those which would not otberwise be practicable because of instability of the pure complex at roo@m temperature and atmospberic press@ure or other factors which might adversely affect its isolatio-Ti from a synthesis mixture. Examples of sueh synthesis mixtures of otherwise impracticable complexes include those, in which the added molecular Lewis base is an amine, such as triphenylamine, pyridine or aniline, or an ethylenically unsaturated lower aliphatic hydrocarbon, such as 1,3-butadiene. Any nickel (II) or nickel (111) compound can be used with a reducing agent in the preparation of these suitafble synthesis mixtures. Exaimples of sur-h compounds include salts of inor.-anic acids, such as nickel bromide and nickel nitrate; salts of catboxylic acids, such as nickelacetate and nickel naphthenate; complexes of nickel salts, si-ich as b is(tripheny,@,phosphine) nir-kel bromide; and icompounds of organic chelating agents, stich as acetylacetone and dimethylglyoxime. Simil,,irly, any reduc;ng a,-ent may be Lised which can lower the valence of nickel to less than 2; including any of the materials disclosed 1-iereinabove as suitable ac.tivators in the process of this invention as well as hydrogen, hydrazines and boron hydrides and hydrocarbyls. The foregoing methods of preparin- non-discrete nickel coordin-ation complexes do not constitute t@he essence of the instant invention, but are set forth merely to, illustrate 6 the applicability of the nickel complex Gontaining reaction prod@ucts in the process of the instant invention. In carrying -out the pr@ocess of this invention, the concentration of nickel complex can be varied over wide range. Although as little as about 0.001% (.by weight of nickcl based on the wei.-ht of diolefin) can be, used, as ;Can concentration of 10% or higher, in -eneral it ;s preferable to use from about 0.5% to about 3% nickel in batch c-perations. In continuous operation, the nickel 10 concentration is advanta.ae,ously somewhat higher; i.e. from about 1% to about 6%. When the nick@-I coordination complexes of this invention are used in :conjunction with an activator or are produced by the reduction of a nickel (II) or nickel (III) 15 compound with a Ziegler type reducing a.@ent, it is essential that precatitions be taken to protect the reaction mixture from excessive quantities of water, alcohol, car:bon dioxide, oxygen and other materials -which are. known to ibe reactive with these activators and reducing agents. 20 Small quantities of such reactive impurities are of course tolerable; however, it is preferred that they be essentially excluded in order to achieve maximum efficiency of the cooligomerization process. The use of an inert reaction medium is not essenti@al 25 to t-he conduct of the process of this invention; however, it is often advantageous to utilize -,L solvent for the nickel coordination coiniplex. Suitible solvents include saturated or non@conju.-ated aliphatic and cyclo aliphatic; hydrocarbons, aryl and alkaryl hydrocarbons, and ring halo30 genated aryl and alkaryl hydrocarbons, preferably containin.-,from a-bout 5 to about 10 carbon atoms. lllustrative of such suitable solvents are n-hexane, isooctane, cyclohexane, cyclopentadiene, 1,5-cyclooctadiene, 1,5cyclodecadiene, 1,5,9-r-yelododecatriene, benzene, toluene, 35 chlorobenzene and p-chlorotoluene. The aryl and alkaril hydrocarbons are particularly preferred. The following examples are illustrative of the process of the instant invention. 40 EXAMPLE I A clean dry 300 ml. stainless steel autoclave equipped with a magnetic stirrer is flushed with argon evacuated and charged successively with one gram of bis(triphenylphosphite) nickel dicarbonyl, forty grams of 1,3-buta45 diene and forty-eight grams of ethylene. Stirring is then initiated and the tempefature of the mixture raised from 24' C. to 149' C. in thirty-four minutes. During this period the pressure within the autoclave rises from 410 p.s.i.g. to 1000 p.s.i.g. Heating is then terminated and the 50 autoclave cooled to 40' C. over a two hour period. At this point, unreacted gases are vented and the reaction mixture filtered. The components of the liquid reaction product that ca-@i be identified by chromatographic and infrared spectrographic analyses are 1,5-cyclooctadiene, 55 4-vinylcyclohexene, 1,5-cyclodecadiene, 1,2-divi nyleyelohexane, 1,4,9-decatriene and l@5,9-cyclododecatriene. The yield of Clo cooligomers is 5.9 grams. EXAMPLES 11-VJII 6ci In each of Examples II-VIII, a clean dry 300 ml. autoclave equipped with a ma,- Iletic stirrer is flushed with nitrogen at atmospheric pressure and charged successively with 0.01 mole of nickel complex (Column A in Table 1) in thirty ml. of solvent (Column B), forty grams of 1,3- 65 butadiene, 0.08 mole of reducing agent (C@olumn C) and forty-two grams of ethylene. Stirring is commenced and the temperature of the reaction mixture raised rapidly to 120' C. The temperature is maintained at 120' C. (-51 C.) for ninety minutes, at which point the autoclave is 70 allowed t<) cool to room temperature. After venting unreacted gases, twenty ml. of methanol is added to the autoclave and the contents are filtered. Qualitative vapor phase chromatographic analysis of the filtrate shows, in each instance, the presence of cooligomers containing ten 75 carbon atoms.
[4]314202904 7 8 TABLEI Example A B c II --------- Nickel carbonyl --------------------- ----------------- ---------- Cyclolioxane -------- Dissobutyl aluminum hydride. III -------- Tri(2-ethylhexyl)phospliite iiielcel tricarboliyl ------------------ Beiizeiie ------------ Pheiiyl magnesiuin bromide. IV -------- Bis(triphen3,laritimoiiite) nickel diedrbonyl -- ------------------ ii-Hexalie ----------- Diethyl aluininum chloride. V --------- Bis(triphenylphosphiiie) iiie-kel dicarboiayl -- ------------------- Benzelie ------------ Ethoxy diethyl alumiiium. VI --- ---- Tris (ti,iphenylphospliite) nickel carboiyl ---------------------- Toli-,ene ------------- n-Butyl litliiuin. VII ------- Teti-akis (tripheiiylpliosphite) nickel --------------------------- Benzene ------------ VIII ------ Bis(eyelooetadietic) nickel - ------------------------------------ 1,5-cyclooetadione -- - IX -------- Dis(triplien@,lstilbiiie) nickel dicarbonyl) ----------------------- Chlorobeiizene ------ Triethylaluminum. X--------- Tris[tri(p-tolyl)phos-,)Iait(,l iiielcel icai-bonyl ------------------- Benzene ------------ Do. XI -------- Tris(triphoiiylplosphite) tripheilyl 1)hosphine nickel ----------- ---- do ------------ -- EXAMPLE XII A mixture of 0.35 mole of triphenylphosphite, 0.03 15 mole of bis(cyclopentadienyl) nickel a-,id ninety ml. of benzene is stirred at 60' C. tinder a blanket of argon in a 500 ml. ffask for one hour. Sixty ml. of the benzene solution is then withdrawn and tetrakis(triphenylphosphite ) 20 nickel recovered by vacuum, strippin.- the benzene and washing the crude product with methanol. The thirty ml. of synthesis solution remaining in the flask are then si-lbstituted for the ptire nickel com-olex and solvent i-@i tie proc,ess of Example VII to produce linear and cyc"c 215 cooligomers of butadiene and ethylene. EXAMPLE XIII The process of Example VII is repeated usirg a mixture of 0.1 mole of triphenylphosphite aid 0.01 mole of bis30 (inder.yl) nickel in place of pure tetrakis(triphenylp osphite) nickel tc) produce cooligomer prodlict. E,XAMPLES Xl"l--XX In each of Examples XRV-XX, which demor@strate the effect of pressure variations, the following procedure is 35 used. A clean dry glass lined autocla@,,e eqi-lipped witn a ma-,netir, stirrer is ptirged with argon for fivc minutes and char-ed with one gram of tripher@ylarsire iiiekel tricar40 bonyl atid thirty graris of dry beilzene. The qiiantities o 1,3-butadiene and ethylene shown in Table II )re then introduced and stirring is commenced as the reaction temperature is rapidly raised to 60' C. A-fter twenty-four hours at this temperature, the ai-itoclave is cooled to roo-ai temperature, vented and its contenls filtered. Liquid reac45 tion product is then isolated by vacuum distillation. the reactor temperature is allowed to drop from 60' C. to room temperature and the unreacted gases are withdrawn and a-@ialyzed. Ethylene recovery is substantially qtiantitative. EXAMPLE XXII A clean dry 300 ml. glass lined atitoclave equipped with a niagnetic stirrer is charged with one gram of bis(tripheiiylarsi-tie) nickel dicarbonyl and twenty ml. of benzene. The autoclave is then flushed with ethylene, sealed and three grams of triisobutyl aluminum in fifteen ml. of betizen.- are added. After stirring the reactor contents for twenty minutps, 54 grams of 1,3-butadiene are introduced and the autoclave pressurized with ethylene to 325 p.s.i.g. Thetemperature is raised to and maintained,at 60' C. for seventeen hotirs. The autoclave is then allowed to cool to room temperattire, unreacted gases are vented and twenty ml. of aqueous phosphoric acid is added to deactivate any remaining alumiium alkyl. Following removal of the aqueotis phase, vaciium distillation of the reaction mixture yields 32.4 g. of liquid cooligomers of the empirical formula CIOH,6 (predominately 1,5-cyclodecadiene and 1,4, 9-decatriene), 18.5 g. of liquid homooligomers of butadiene (predominately 1,5- cyclooctadiene and 1,5,9-cyclododecatrione) and 9.6 g. of non-volatile butadiene polymer. EXAMPLES XXIII-XXX The following -eneral procedtire is used in Examples xxili-xxx. A clean dry 300 ml. stainless steel autoclave equipped with a magnetic stirrer is evacuated and then charged with thirty ml. of dry benzene and four .-rams of 1,3butadier@e. Stirring is commenced and the nickel comTABLE 2 Monomer Charge Initial Final Theoret; cal Actual Yield Cooligomer Mol ratio pressure pressure yield 2 2 Butadione/ Yield Exainple 1,3-but@,diene Ethylene butadiene: at 60' C. at 60' C. Butediene/ Ethylene percent (g.) (g.) ethylene (P.S.i.g. ) (P.S.i.g.) Ethylene Cooligomers theory cooligoule,@S (g) xiv ----------- 27 28 1:2 500 480 34 16.6 48.8 xv ------------ 54 14 2:1 300 160 68 3.5 51.5 xvi ----------- 54 7 4:1 190 115 34 15.2 47.8 xvii ---------- 54 7 4:1 1400 400 34 18.4 54.1 xviii --------- b4 2.8 10:1 145 90 13.6 7. 4 54.4 xix ----------- 54 2.1 15:1 104 73 10.2 1.7 16.7 xx ------------ 54 1.7 20:1 75 50 7.1 (2) < 1 1 Autoclave, pressure maintaiiied at 400 p.s.i.g. -,vitli nitrogen. 2 Trace (<S mg.). EXAMPLE XXI 65 The process of Example XV is repeated under a reactor pressure of 0-5 p.s.i.g. by introducing th-, gaseous mi,-- ture of but,,idiene and ethvlene beneath the s,,irface of the liquid benzene solvent throu-h a fritted glass disc. The vapor space above the solve-,it is conLinuoi-,.sly vepted 70 into an external reservoir which is -iiaintained at reaction temperature and from w@ticli iiireected gases are re--yeled to the reactor throti,-h the fritted .-lass disc. The p, s flow rate through the fritted disc is mai-iitai-ried at betweeii thirty and fifty liters per hour. After tweiity-four ho,,irs, 75 pound, electron donor and reducin-, a.-ent (all as shown in Table, 3) are successively introduced. The autoclave is then presstired to 300 p.s.i.,-. with ethylene and brought rapidly to reaction temperature, which is maintained for a specified time. During this reaction period, additional ethylene is introduced ,vlien necessary to maintain total reactor pressure above 300 p.s.i.g. At the end of the reaction period, the autoclave is rapidly cooled and vented and twenty ml. of isopropanol are added to deactivate the catalyst. Reaction products are separated by vacutim distillation and analyzed.
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