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Home , Hydrogen iodide

United States Patent (19) 11, 3,933,861 Kurkov (45) Jan. 20, 1976

54 PRODUCTION OF TETRAHYDROFURANS o Primary Examiner-Harry I. Moatz 75 Inventor: Victor P. Kurkov, San Rafael, Calif. Attorney, Agent, or Firm-G. F. Magdeburger; John 73 Assignee: Chevron Research Company, San Stoner, Jr.; W. Keith Turner Francisco, Calif. 22 Filed: Jan. 7, 1974 21 Appl. No.: 431,258 57) ABSTRACT 52 U.S. Cl...... 260/346.1; 252/43) R; fif Tetrahydrofurans are produced by the codimerization 5 Int. C.? C07D 307/08 of an oxide with an alkene in the presence of 58) Field of search. 260/346.1 catalytic amounts of a Group VIII noble transition wrwr. was awsus woup a sw w ...... d metal compound and an promoter. 56 References Cited UNITED STATES PATENTS 11 Claims, No Drawings 3,317,567 51967 Linn...... 260/346. R

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3,933,861 1 2 Examples of Pd compounds of formula (I) include Pd PRODUCTION OF TETRAHYDROFURANS halides such as PdCl and Pd, Pd carbonyl halides such as Pd(CO)Cl. and Pd(CO)Cl., Pd organophos DESCRIPTION OF THE PRIOR ART phines such as Pd(P(C6H5)3)4, Pd(P(C6H5)3], W. J. Linn and R. E. Benson, J. Amer. Chem. Soc., PdClP(CH), Pd(P(C6Hs), and 87, 3057 (1965), disclose the addition of tetracyano Pd(NO), P(CH)a), and Pd compounds such as oxide to olefins by cleavage of the C-C bond PdCl As(CH3) and Pd(Sb(CHs)). of the epoxide ring to give tetracyanotetrahydrofurans. A preferred class of Pd compounds is represented by the empirical formula (II): SUMMARY OF THE INVENTION O Pd(L)(X) () It has now been found that an alkene oxide codimer izes with an alkene in the presence of a catalyst system wherein x is 0 to 4 and y is 0 to 2, the sum of x + y is comprising a Group VIII noble transition metal (Ru, 2 to 4, and L and X have the same significance as de Rh, Pd, Os, Ir, Pt) and an iodide promoter to produce fined in formula (I). As in the case of Ru compounds, tetrahydrofurans. 5 the L and X ligands are preferably carbon monoxide, halides and organophosphines, as defined above. The DESCRIPTION OF THE INVENTION preferred palladium compounds are zero-valent Pd organophosphine compounds. The Catalyst System Examples of suitable rhodium compounds include Rh The catalyst system employed in the process of the 20 halides such as RhCl3, RhBra and Rhia, rhodium car invention comprises a Group VIII noble transition bonyl halides such as Rh(CO), Br, Rh(CO)4C1, and metal compound and an iodide promoter. Rh(CO), and Rh coordination compounds such as The transition metal compound suitably is a zero Rh(CH)P)(CO) and RhCl(CO) (CHs)As). valent to tri-valent compound. Preferably, however, Examples of suitable iridium, osmium and platinum the transition metal compound is low-valent, e.g., a 25 compounds include IrCl3, Ir,(CO)1, Os(CO)Cl., zero-valent, mono-valent or di-valent compound. A Pt(CO)Cl. Pt(CO)CL, and Pt(CO)Cl. preferred class of transition metal compounds is repre The preferred transition metal compounds are Ru, sented by formula (I): Rh, Pd and Ir compounds, and the most preferred tran M(L)(X), (I) 30 sition metal compounds are Ru and Pd compounds. wherein M is Ru, Rh, Pd, Os, Ir or Pt, n is 0 to 5 inclu The iodide promoter component of the catalyst sys sive, n is 0 to 3 inclusive, the sum of n + n is 3 to 6 tem suitably includes , iodide (hydroi inclusive, L is a ligand which is complexed with the odic acid), alkyl and iodohydrins. Suitable alkyl metal moiety, and X is a ligand which is bonded to the iodides are those of to 6 carbon atoms and l to 3 35 iodide groups such as methyl iodide, ethyl iodide, metal moiety. It is appreciated, of course, that the sum diiodide, and . of n + m represents the coordination number of the Suitable iodohydrins are vic-iodohydrins of 2 to 6 car transition metal compound, i.e., the transition metal bon atoms produced by cleavage of an alkene oxide compound is three-, four-, five- or six-coordinate, and with hydrogen iodide such as 2-iodoethanol, 2-iodo that m represents the valency or oxidation state of the 40 propanol, 1-iodopropan-2-ol, 2-iodobutan-1-ol, etc. metal moiety. It is to be understood that the transition The preferred iodide promoter is hydrogen iodide. metal compound depicted in formula (I) represents Molar ratios of the iodide promoter to the transition only the empirical composition of the metal compound metal component of the catalyst system in the range of and that the metal compound may exist in a dimeric or 1:1 to 2000:1 are generally suitable. However, the pre polymeric form. 45 ferred molar ratios of iodide promoter to transition Examples of suitable L ligands are water, carbon metal component are about 3:1 to 300:1, and the most monoxide, olefins, organophosphines, organoarsines, preferred molar ratios are about 10:1 to 150:1. organostibines, organobismuthines, and like non-ionic Concentrations of the transition metal component of organic ligands which are complexed to a transition the catalyst system in the reaction medium between metal. Examples of suitable X ligands are halides - 50 10 mol/liter and 10 mol/liter are normally em e.g., F. Cl, Br or I - hydride, nitrite, and like organic ployed, with the preferred range being 10 mol/liter to or inorganic anions which are bonded to a transition 10 mol/liter. Higher concentrations, even to the ex metal. Preferred X and Lligands are carbon monoxide, tent of 1 mol/liter, may be used, however, if desired. halides, and organophosphines. Particularly preferred The concentration of the iodide promoter portion of organophosphines are trihydrocarbylphosphines of 3 to 55 20 carbon atoms, especially triarylphosphines such as the catalyst system in the reaction medium may vary triphenylphosphine. widely over the broad concentration range of 10 illustrative Ru compounds of formula (I) include Ru mol/liter to 2 mols/liter, based on iodine. In the process halides such as Rucla, RuCl-3HO, RuBra and Rua, Ru of this invention, however, the preferred concentration carbonyl halides such as Ru(CO), Ru(CO)Cl. and 60 range of promoter is 10 mol/liter to 1.5 mols/liter. Ru(CO), Ru carbonyls such as Ru(CO)5 and Ru(- Alkene Oxide Reactant CO)4), Ru organophosphine compounds such as Ru(- CO),(P(CH)ala, Ru(CO) P(C6H5)a), RuCl(CO) The alkene oxide reactant has 2 to 6 carbon atoms, (P(C6H5)3), RuHCl(CO) P(CHs), etc.; and Ru com and is represented by the following formula (Ill.) pounds such as Rucle(CO) AS(CH) and Ru(- 65 CO), Sb(CH5). O The preferred Ru compounds are Ru carbonyl or RRC CRR () ganophosphines. 3,933,861 3 4 where R', R, R and Rare hydrogen or an alkyl group ane. In some modifications of the process, a portion of of 1 to 4 carbon atoms. Examples of suitable alkene the alkene reactant suitably serves as the reaction dilu oxide reactants are ethylene oxide, propylene oxide, ent, and no additional diluents are employed. When 1-butene oxide, 2-butene oxide, l- oxide, 2 diluent is employed, up to about 10 mols per mol of pentene oxide, 1-hexene oxide, 3-methyl-l-butene alkene oxide reactant are satisfactory. The process is oxide and 2,3-dimethyl-2-butene oxide. Preferred al suitably conducted in an inert reaction environment, so kene oxide reactants are oxides of n-, especially that the presence of reactive materials such as oxygen ethylene oxide and propylene oxide. and water are desirably avoided. The process of the invention is carried out by inti Alkene Reactant O mately contacting the alkene oxide and alkene in the The alkene reactant has 2 to 6 carbon atoms and is presence of the transition metal compound and iodide represented by the formula (IV) promoter. A variety of procedures can be employed for RRC=RR (IV) contacting the reaction components with the catalyst where R, R, R and Rare hydrogen or an alkyl group 15 system. In one modification, the entire amounts of of to 4 carbon atoms. Examples of suitable alkene alkene oxide, alkene and catalyst components are reactants are ethylene, propylene, 1-butene, 2-butene, charged to an autoclave or similar pressure reactor and isobutylene, l-pentene, 3-methyl-l-butene and 2-hex maintained at reaction conditions for the desired reac ene. Preferred alkene reactants are n-alkenes, and par tion period. In another modification, an active catalyst ticually preferred alkene reactants are terminal n 20 system is initially preformed by contacting at elevated alkenes, especially ethylene and propylene. temperature the transition metal compound and iodide promoter in a suitable solvent and subsequently adding Tetrahydrofuran Products the remaining reaction components. In terms of the alkene oxide and alkene reactants The process of the invention is conducted at moder depicted by formulas (III) and IV), the codimerization 25 ate temperatures and pressures. Suitable reaction tem reaction may be depicted as follows: peratures varying from about 100°C. to 250°C. are satisfactory, and reaction temperatures varying from O R. O. R. about 150°C. to 200°C. are preferred. The process is / N / M conducted at or above atmospheric pressure, and pres RRCCRR - RRC=RR -) R- -R" ( ) 30 sures from about l atmosphere to about 200 atmo (ii) (IV) R-C-C-R spheres are satisfactory. Reactants which are normally gaseous, e.g., ethylene, ethylene oxide, etc., are conve (V) niently employed at partial pressures of 1 psia to 2000 35 psia, preferably 100 psia to 1000 psia. where the R groups are hydrogen or alkyl groups of 1 to At the conclusion of the reaction, the product mix 4 carbon atoms. By way of illustration, the reaction of ture is separated and the tetrahydrofuran product is propylene oxide and ethylene produces 2-methyltet recovered by conventional means, such as fractional rahydrofuran; the reaction of 2-butene oxide and ethyl distillation. Unreacted reaction components are suit ene produces 2,3-dimethyltetrahydrofuran; and the 40 ably recycled for further use in the process. reaction of 2-butene oxide and 2-butene produces 2,3,4,5-tetramethyltetrahydrofuran. EXAMPLES - 2 The tetrahydrofuran products have utility as solvents, The codimerization of ethylene oxide or propylene as they are miscible with a variety of substances such as oxide with ethylene in the presence of Ru(- alcohols, ketones, esters, and . 45 CO)3P(C6H5)3) and an iodide promoter was con They also dissolve polymers such as polyvinylchloride. ducted in a series of experiments according to the fol In addition to the tetrahydrofurans, the process of the lowing procedure. invention also produces other products. For example, A rocker bomb was charged with the ruthenium com the alkene oxide is generally also isomerized and/or pound and flushed with . The iodide promoter, reduced to an alkanol or a carbonyl compound; e.g., 50 ethylene oxide and solvent were then added to the ethylene oxide may be converted to ethanol or acetal autoclave. The autoclave was sealed and pressured dehyde, and propylene oxide may be converted to ace with ethylene and rapidly heated to reaction tempera tone. Also, the alkene reactant may be polymerized, e.g., ethylene may be polymerized to polyethylene. ture. Each experiment was conducted with 0.5 to 1.5 55 mmol of the ruthenium compound, 50 to 130 mmol of The Reaction Conditions iodide promoter, 0.5 mol of ethylene oxide or propy In the process of the invention, the alkene:alkene lene oxide, 1.4 mol of ethylene and 1.1 mol dry, deoxy oxide molar ratios are suitably from about 10:l to 1:10. genated benzene solvent (except Run No. 2, wherein However, preferably the molar ratios of alkene:alkene acetonitrile was employed). oxide are from about 10: l to 1:1. 60 After the reaction was completed, the rocker bomb The process of the invention is conducted in a fluid was opened and the reaction mixture analyzed by gas phase, i.e., either in the gaseous or liquid phase, in the liquid chromatography. presence or in the absence of an inert reaction diluent. The iodide promoter, reaction temperature, pressure Suitable inert, normally liquid diluents are hydrocar and time, conversion of propylene oxide or ethylene bons free from aliphatic unsaturation such as , 65 oxide, mol% yield of tetrahydrofuran (THF) based on , , , , benzene, tolu converted ethylene or propylene oxide are tabulated in ene and xylene. Suitable normally gaseous diluents are Table I. In Run I, the product is 2-methyltetrahydrofu nitrogen, hydrogen, argon, helium, and eth

3,933,861 5 6 of iodine, hydrogen iodide, alkyl iodide and iodohy EXAMPLES 13–23 drin, at a temperature from 100°C to 250°C. The codimerization of ethylene oxide and ethylene in 2. The process of claim 1 wherein M represents Ru or the presence of a variety of transition metal compounds P. and hydrogen iodide promoter was conducted by a 5 3. The process of claim 2 wherein the alkene oxide is procedure similar to that employed for Examples 1-12. an n-alkene oxide and the alkene is a terminal n-alkene, Each experiment was conducted at a temperature of and the molar ratio of alkene to alkene oxide is 10:1 to 150°C. with 1 to 1.5 mmol of the transition metal com 1:1. pound, 50 to 130 mmol of hydrogen iodide, 0.5 mol of 4. The process of claim 3 wherein m is 0. ethylene oxide, 1.3-1.4 mol ethylene and 1.1 mol dry, 10 5. The process of claim 3 wherein M represents Ru deoxygenated benzene solvent. and L represents CO. The transition metal compound employed, reaction 6. The process of claim 3 wherein the alkene oxide is pressure, conversion of ethylene oxide and the mol% ethylene oxide, the alkene is ethylene, and the ethylene yield of tetrahydrofuran (THF) based on converted is provided at an initial partial pressure of 100 psia to ethylene oxide are tabulated in Table II. 15 1,000 psia. In Table II, is represents phenyl. 7. The process of claim 3 wherein the alkene oxide is TABLE I Yield Ru Temp., Time, Press., Conver- THF. Ncy. Promoter Alkene Oxide (C. hrs. psig sion, % mo% H Propylene oxide 150 5 4. 37 9 2 H Ethylene oxide 25 5 60 23 22 3. H Ethylene oxide 150 5 670 38 28 4 H Ethylene oxide 75 5 870 84 2O 5 H Ethylene oxide 150 5 490 5 64 H Ethylene oxide 50 5 650 49 22 7 H Ethylene oxide 50 3 88O 30 35 8 H Ethylene oxide 50 5 OO 45 3. 9 H/, Ethylene oxide 50 7 O3O 55 9 O H Ethylene oxide SO 3 SSO 4 49 H Ethylene oxide 50 8 720 76 9 2 HOCHCH, Ethylene oxide 50 8 250 2 21

TABLE THF Run Tine, Press., Conver- Yield N. Catalyst hrs. psig sion, it 13 (P)(CORu 8 1080 65 32 4. RuCXHO 18 O8 34 2 5 (dPRuCl 7 OOO 87 s 6 (CO)Rud PCHCHPd) 5 82O 46 7 7 Ru(CO). 8 88 58 7 8 Ru(CO) P 8 060 33 5 9 Pd(P) 5 100 13 3O 35 3 2 (hP)(CO)C 8 850 64 4 22 H only 8 000 2S O 23 (b)(CO)aRu (with- 8 850 30 out promoter) as propylene oxide, the alkene is ethylene and the ethyl What is claimed is ene is provided at a partial pressure of 100 psia to 1. A process for producing tetrahydrofurans which 1,000 psia. comprises codimerizing in the gaseous or liquid phase 8. A process for producing tetrahydrofurans which an alkene oxide of 2 to 6 carbon atoms of the formula comprises codimerizing in the gaseous or liquid phase so an alkene oxide of 2 to 6 carbon atoms of the formula O 1 N. O RRC-CRR / N RRCCRR with an alkene of 2 to 6 carbon atoms of the formula 55 R5RC=CRR wherein R,R,R,R,R,R,R, and with an alkene of 2 to 6 carbon atoms of the formula R represent hydrogen or an alkyl group of 1 to 4 car RRC=CRR wherein R, R2, R, R4, R,R,R, and bon atoms, in the presence of catalytic amounts of a R, represent hydrogen or an alkyl group of 1 to 4 Group VIII noble transition metal compound of the carbon atoms, in the presence of catalytic amounts of a formula M(L)(X), wherein M represents Ru, Rh, Pd, 60 Zero-valent ruthenium or palladium trihydrocarbyl Os, r or Pt; n is 0 to 5 inclusive; n is 0 to 3 inclusive; of 3 to 20 carbon atoms and an iodide pro n+ m is 3 to 6 inclusive; L represents non-ionic organic moter selected from the group consisting of iodine, ligands complexed to M selected from the group con hydrogen iodide, alkyl iodide, and iodohydrin, at a sisting of water, carbon monoxide, olefin and hydro temperature from 100°C to 250°C. carbyl phosphine, , , and ; and 65 9. A process for producing tetrahydrofurans which X represents inorganic bonded to M selected from comprises codimerizing in the gaseous or liquid phase the group consisting of halide, hydride and nitrite, and an alkene oxide of 2 to 6 carbon atoms of the formula an iodide promoter selected from the group consisting 3,933,861 8 7 alkyl iodide and iodohydrin, at a temperature from 100° to 250°C. O M. N. 10. The process of claim 9 wherein the alkene oxide RRC CRR is ethylene oxide, the alkene is ethylene and the iodide promoter is iodine, hydrogen iodide, an alkyl iodide or with an alkene of 2 to 6 carbon atoms of the formula an iodohydrin. RRC=CRR wherein R, R2, R, R, R, R, and R' 11. The process of claim 9 wherein the alkene oxide represent hydrogen or an alkyl group of 1 to 4 carbon is ethylene oxide, the alkene is ethylene, and the ethyl atoms, in the presence of catalytic amounts of a ruthe ene is provided at an initial partial pressure of 100 psia nium or palladium carbonyl trimethylphosphine or O to 1,000 psia, the iodide promoter is hydrogen iodide triphenylphosphine and an iodide promoter selected and the catalyst is Ru(CO)a(P(C6Hs). from the group consisting of iodine, hydrogen iodide, k sk sk k

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