United States Patent (19) 11 3,968,133 Knifton (45) July 6, 1976

54 CARBOXYLATION PROCESS FOR 3,723,486 3/1973 Kajimoto...... 260/410.9 R PREPARING LINEAR FATTY ACDS OR 3,776,929 12/1973 Mrowca...... 260/410.9 R ESTERS 3,819,669 6/1974 Knifton...... 260/410.9 R 3,832,391 8/1974 Parshall...... 260/410.9 R (75) Inventor: John F. Knifton, Poughouag, N.Y. Primary Examiner-Patrick P. Garvin 73 Assignee: Texaco Inc., New York, N.Y. Assistant Examiner-John F. Niebling 22) Filed: Nov. 25, 1974 Attorney, Agent, or Firm-T. H. Whaley; C. G. Ries; (21) Appl. No.: 526,867 Bernard Marlowe

52) U.S. C...... 260/410.9 R; 260/413; 57 ABSTRACT 260/497 A; 260/488 K; 260/491; 260/.532; This invention concerns a process for preparing linear 260/533 A fatty (carboxylic) acids and esters from the reaction of 51 Int. Cl’...... C11C 3/02 olefins, (or water) and monoxide. The (58) Field of Search...... 260/410.9 R, 413, 497 A, process is catalyzed by catalytic amounts of disper 260/488 K, 491, 532,533 A sions of ligand-stabilized, palladium(II) halide com plexes, in quaternary ammonium, phosphonium or ar 56 References Cited sonium salts of trihalostannate(II) or trihaloger UNITED STATES PATENTS manate(II). These empirically selected palladium cata 3,437,676 4/1969 Kutepow...... 260/410.9 R lysts can be recycled with fresh olefin feed several 3,530, 155 9/1970 Fenton...... 260/410.9 R times before substantial loss of catalytic activity is 3,530,168 9/1970 Biale...... 260/410.9 R encountered. 3,657,368 4, 1972 Parshall...... 260/410.9 R 6 Claims, No Drawings 3,700,706 10/1972. Butter...... 260/410.9 R 3,968, 133 2 While these homogeneous catalysts are a vast im CARBOXYLATION PROCESS FOR PREPARING provement over the more easily poisoned and less se LNEAR FATTY ACDS OR ESTERS lective heterogeneous catalysts, and the widely used highly toxic metal carbonyls such as nickel, cobalt and STATEMENT OF INVENTION 5 iron cabonyls. They also have certain drawbacks. This invention relates to the catalytic conversion of These include difficulties in maintaining high conver alpha-olefins to linear fatty acids or esters. sions, high selectivities and high yields upon recycling More particularly, this invention concerns the car the catalyst, due to catalyst degradation, and the prob boxylation of alpha-olefins with carbon monoxide in lems of mechanical losses, and further catalysts decom the presence of hydroxyl-containing co-reactant, under 10 position, during the separation of the carboxylated moderate conditions of temperature and pressure, products from the homogeneous catalysts and solvents. using dispersions of certain ligand-stabilized palladium Catalyst instability is a particular problem with the less (II) halides in quaternary ammonium, phosphonium thermally stable palladium-containing homogeneous and/or arsonium salts of trihalostannate (II) or trihalo catalysts. germanate(II). 15 Carboxylation, as used througout this disclosure and CLOSEST PRIOR ART AND DISTINCTIONS OF claims, refers to the process of preparing saturated, THIS INVENTION OVER SAID ART preferably linear carboxylic acids or their esters from The closest prior art that the applicant is aware of is alpha-olefin substrates. Linear paraffinic carboyxlic U.S. Pat. No. 3,657,368 (G. W. Parshall). This patent esters are of the type: RCOOR", wherein R is a satu 20 describes the use of certain transition metal halides in rated alkyl radical containing 3 to 40 carbon atoms, combination with molten quaternary ammonium or wherein R' is an aliphatic or aromatic radical. phosphonium trihalostannate(II) and trihaloger BACKGROUND OF THE INVENTION manate(II) salts as catalysts for the carboxylation, hy Carboxylic acids are characterized by the presence of ? droformulation, and isomerization of one of more carboxyl groups in an organic molecule. olefins, and the hydrogenation of nitriles. The acids are usually written as RCOOH. The hydro The following differences of substance are believed gen atom of this group may be displaced and appear as to patentably distinguish applicant's claimed invention a hydronium ion thereby justifying by theory the term from the disclosure of Parshall. 1. While Parshall osten acid. 30 sibly discloses platinum and palladium halides dis Saturated linear carboxylic acids and their esters may persed in molten quaternary ammonium or phospho be prepared by a large number of general procedures nium trihalostannate(II) and trihalogermanate(II) salts such as the oxidation of primary alcohols or aldehdyes, for the catalytic carboxylation of alpha-olefins, no pal the catalytic hydrolysis of nitriles, the reaction of ladium-containing catalysts are specifically named or Grignard reagents with carbon dioxide as well as by 35 described by Parshall, much less employed. several special procedures for specific acids including The sole “disclosure' can be found in Column 2, fermentation, the acetoacetic ester synthesis, the ma lines 21-32, more specifically, lines 22-25, ". . . . (A) lonic ester synthesis and the Reformatsky reaction. at least 0.05 weight percent of a chloride, bromide or In recent years, with the availability of large quanti iodide-containing salt of a metal having an atomic num ties of alpha-olefins from cracking at relatively low 40 ber of 22–28, 40-46 or 72-79, and (B) . . . ' costs, alpha-olefins have been considered as starting The following reasons are evidenciary of why the materials for fatty acid production. Parshall patent does not constitute a bona fide disclo The carboxylation of olefins in the presence of metal sure of the use of the analogous palladium catalysts carbonyls or carbonyl precursors to produce carboxylic even to those skilled in the art: acids or esters is old in the literature, originally having 45 1. While it is known that palladium has an atomic been developed by Reppe and his coworkers. How number of 46 and Column 2, lines 21 to 32 states that ever, the nickel and iron salts or carbonyl precursors metal halides of 40-46 are useful as catalytic entities, suffer from some major drawbacks. These drawbacks this disclosure is sufficient to characterize the specific include the high toxicity of the carbonyl type reagents, components of active palladium containing catalysts in the production of a variety of undesirable side products 50 order to reject applicant's specifically claimed catalysts due to polymerization, isomerization and reduction of on Parshall. the olefin substrates and most importantly, the reaction 2. A further reason why this type of "tour de force' results in the production of large quantities of branched disclosure is a meaningless teaching to reject appli isomers in addition to the desired linear fatty acid prod cant's claims is that it is well documented in the patent uct. 55 literature that catalysis is a most unpredictable art and *This work is reviewed by C. W. Bird, Rev.62,283 (1962) does not lend itself to broad generic disclosures sup Recently, it has been shown that the production of ported by only a few isolated species, particularly when polymeric, isomeric and reduced products can be such broad disclosures can encompass many catalyst avoided through the use of alternative homogeneous species which are not available for testing or are even catalyst systems which are active under mild reaction 60 unknown. For instance, virtually every component of a conditions and which give good yields and selectivity to multi-component homogeneous platinum(II) or pal the desired linear fatty acids or esters. These catalyst ladium(II) catalyst system, such as the noble metal systems consist of ligand-stabilized platinum(II) and employed, the nature of the halide salt, the presence of palladium(II) halide complexes in combination with absence of stabilizing ligands, the structure of the mol Group IVB metal halides. They are exemplified by: 65 ten quaternary ammonium or phosphonium trihlaos PtCl(ASCCH)-SnCl2 (U.S. Pat. No. 3,819,669) tannate(II) or trihalogermanate(II) salts present can and each affect not only the degree of conversion, selectiv PdCl(P(CH)l-SnCl (U.S. Pat. No. 3,700,706). ity and yield but, in some cases, even the operability. 3,968,133 3 4. These statements are confirmed by the data in Tables 1 g. 10 (C2H5)4NSnCla-PodCl2P(p-CHO.CH4)32 and 2. h. 10 (CH)NSnCl-PdCl2P(CH3)2C6H5) In re Grant, 134U.S.P.O.248, among others. i. 5 (CH)NIGeCl-PdCl2P(C6H5)2 3. Many of the catalyst compositions disclosed gener j. 5 (CH)N(GeCla-PdCl2(AsOCH5)3)2 ally in U.S. Pat. No. 3,657,368 (See Column 2, lines 5 k. 10 (CH)N(SnCla-PodCl2(P(C6H5)3)2 21-32) and specifically (See Column 2, lines 38-45) 1. 10 (CH)NSnCla)-PdCl2(AsOCH5)3)2 for the carbonylation of olefins have been found inac Of the 12 catalyst compositions described supra, the tive by us for the carboxylation of a-olefins, as exempli palladium calalyst compositions (a) through (j) (inclu fied by 1-octene, to linear esters, such sive) have been found to show superior performances as vinyl nonanoate under experimental conditions 10 compared to analogous platinum catalysts disclosed by where the preferred ligand-stabilized palladium(II) Parshall for the carboxylation of a-olefins. Compara catalysts, such as (C2H5)4NSnCl-PdCl2(P(C6H5)3)2 tive data are summarized in Tables 1 and 2 for the show good activity. This is confirmed by the data in typical synthesis of ethyl nonanoate from 1-octene Table 2. under standard experimental conditions. 4. When the closest platinum-containing catalyst 15 More generally it is anticipated that the palladium disclosed by Parshall for the carboxylation of alpha catalysts of this invention should consist of ligand olefins; stabilized palladium(II) halide complexes dispersed in 10 (CH)NSnCl)-PtCl(P(CH)) quaternary ammonium, phosphonium and arsonium is run side by side with the analogous palladium catalyst salts of trihalostannate(II) and trihalogermanate(II) utilized by applicant, viz. 20 wherein: 10 (CH)NSnCla-PodCl2P(CH) a. The stabilizing ligands contain one or more phos under identical reaction conditions, to carboxylate the phorous or arsenic donor atoms bonded to various same alpha-olefin, an improvement in conversion of alkyl, aryl or substituted aryl groups. more than 25-fold and an increase in yield of over b. The palladium halide salt is palladium chloride or 70-fold is noted and the purity of product is even higher 25 bromide, and with the palladium catalyst. This statement is con c. The quaternary ammonium, phosphonium or ar firmed by the data in Table 1. Similarly, the platinum sonium salts contain alkyl, cycloalkyl, aryl, substi (II) catalyst (CH)N(SnCla)-PtCl disclosed by Par tuted aryl, substituted alkyl and mixed alkaryl shall in Column 10 Example 27 of the same patent, groups each having 1 to 12 carbon atoms, or mix gives only trace amounts of carboxylic acid ester under 30 tures thereof. the mild conditions preferred for the palladium cata B. General Description and Discussion for the Car lysts disclosed herein. This statement is confirmed by boxylation of Olefins the data in Table 2. In the broadest process embodiment envisioned, the 5. In addition to differences in the choice of noble substrate olefin would be contacted with a catalytic metal employed for the carboxylation reaction (e.g. 35 amount of a dispersion of ligand-stabilized palladium palladium catalysts claimed here by applicant versus (II) halide complex in quaternary ammonium, phos the platinum catalysts taught by Parshall) the applicant phonium or arsonium trihalostannate(II) or trihaloger has also found that improved yields of fatty acid esters manate(II) salt, in the presence of sufficient quantity of are generally obtained using molar ratios of quaternary hydroxylated coreactant and carbon monoxide to sat tin(II) or germanium(II) salt component to noble metal 40 isfy the stoichiometry of the carboxylation reaction, at component of between 5 to 10 rather than the ratios of elevated temperatures and under superatmospheric 100 or more practiced by Parshall. Evidence for this pressure for a time sufficient to form the desired linear statement may be found in Tables l and 3. fatty acid or ester products. 6. Most important from a commercialization stand Ordinarily, the catalyst is prepared in situ, in the point, the empirically selected palladium-containing 45 absence of oxygen or oxidizing agents, preferably in an catalyst complexes claimed by the applicant show ex inert environmenrt such as is afforded by a nitrogen or cellent capability for recycling compared to the analo other inert gas atmosphere, in a reactor which is gous platinum catalysts disclosed by Parshall. This is equipped for pressurized reactions at elevated temper proven when the reaction mixture containing fresh atures. While it is generally less convenient, the catalyst a-olefin, carbon monoxide are run in a continu 50 can be preformed, and contacted with the degassed ous process for producing fatty acid ester products olefin to be carboxylated, under said inert purge and without exhibiting substantial loss in yield or selectiv hydroxylated coreactant, pressurized with carbon mon ity. This unexpected property greatly reduces operating oxide, sealed and heated under the superatmospheric costs by cutting down regeneration of the palladium pressure for the required time, cooled, vented off, and catalysts and so far as is known is not reported in the 55 the product mixture recovered for work-up. literature. Evidentiary of this recycle capability of the Generally, the quaternary ammonium, phosphonium (CH)NSnCla-PodCl2P (C6H5)3)2 and or arsonium trihalostannate(II) or trihalogermanate(II) (CHs)NSnCla-PdCl2P(p-CH3CH4)3 catalysts salt, and the ligand-stabilized palladium(II) dihalide are may be found in Tables 4 to 6. The following palladium contacted with a degassed sample of olefin (to be car catalyst compositions have been found to be active for 60 boxylated) and alcohol co-reactant under an inert gas the carboxylation of o-olefins to linear fatty acids or purge and are transferred to a reactor which is deoxy esters: genated, pressurized with carbon monoxide and heated a. 10 (C.H.)N(SnCla)-PdCl2(P(p-CH3CH.)al, until analysis or experience has shown that the carbox b. 10 (C2H5(NSnCls-PodCl2P(C6H5)3)2 ylation reaction is substantially complete. c. 5 CCH(CH)PSnCla)-PdCl2P(C6H5) 65 C. Work-up of Carboxylated Reaction Mixture d. 10 (n-C4H9)4N](SnCla-Paclip(C6H5)2 Two work-up procedures have been practiced. In one e. 5 (CH)AsOSnCla-PodCl2(P(C6H5)2 case the product ester may be recovered by a solvent f. 5 (CH)NSnCl-PdCl2P(C6H5)2 extraction technique as follows: 3,968,133 S 6 1. a. The crude liquid ester product is separated from The time of reaction may vary from a few minutes to the product mixture by filtration, centrifugation, twelve hours or more. Generally substantial conver etc. sions of the o-olefin can almost always be accom b. The crude ester is subject to flash distillation under plished within 2 to 8 hours. Table 3 provides the sup reduced pressure to remove unreacted olefin and porting experimental data which establish these ranges excess alcohol, in experimental conditions. c. The partially purified ester is extracted with a G. Alpha (60) Olefins as Substrates non-polar solvent, such as petroleum ether, to pre Alpha-olefins ranging in carbon content from three cipitate dissolved melted components, (3) up to forty (40) carbon atoms can be employed. d. The non-polar extract is distilled to recover resid O Illustrative linear alpha olefin substrates include 1-pro ual ester, and pene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1 e. The recovered melt catalyst from steps (a) and (c) octene, 1-nonene, 1-, 1-undecene, 1-dodecene, is combined and recycled with additional olefi 1-tetradecene as well as their higher homologues such and alcohol. as 1-heptadecene, 1-octadecene, 1-eicosene, tricosene, An alternative recovery procedure is recovery of the 15 1-pentacosene, etc. Branched alpha-olefins can also be product ester by a vacuum distillation technique, as carboxylated. Illustrative branched alpha-olefin sub follows: strates are 3-methyl-1-pentene, 4-methyl-1-pentene, 2. a. The crude liquid ester product is separated from 4,4-dimetyl-1-pentene and 3,6,9-triethyl-1-decene. the product mixture by filtration etc. These olefin substrates may be utilized neat or in con b. The crude liquid product of (a) is subject to distil 20 junction with one of more inert background solvents lation under reduced pressure to strip off unre such as octanes and the like. The alpha-olefins can be acted octene and alcohol, in the form of single, discrete compounds or in the form c. The partially purified ester is subject to fractional of mixtures of olefins. In the latter case these comprise distillation in vacuo, mixtures of Cs to Cao carbon containing alpha olefins. d. The recovered residual melt catalyst from steps (a) 25 Usually these mixtures have a spread of from 4 to 8 and (c) is combined, and recycled with additional carbon atoms. Because of their relatively low cost, olefin and alcohol. mixtures of alpha-olefins ranging in carbon content D. Molar Ratio of Tin or Germanium Halide to pal from Cs to Co and upwards are favored substrates for ladium(II) Halide carboxylation wherein the ligand-stabilized palladium As can be seen from the data of Tables 1 and 3, while 30 (II) halides dispersed in quaternary ammonium triha the ratio of tin or germanium to palladium in the cata lostannate(II) or trihalogermanate(II) salts are em lyst is not critical for operability, consistently higher ployed as carboxylation catalysts at sufficiently ele conversions, yields and selectivities can be obtained vated temperatures and pressures. using molar ratios of tin (or germanium) to palladium H. Hydroxyl-containing co-reactants ranging from 1 to 100 mole Sn(Ge) per mole of Pd. 35 This terms as employed throughout this application However, inasmuch as the highest conversions, selec refers to water and other hydroxyl-containing reactants tivities and yields of ester are produced at molar ratios which contain at least one hydroxyl group which is of tin (or germanium) ranging from 5 to 10 mole per sufficiently labile during the reaction conditions of the mole of palladium, this represents the preferred molar carboxylation reaction to produce the desired carbox range of tin or germanium to palladium. Interestingly 40 ylated product. The physical form of the hydroxyl-con enough, the Parshall patent discloses much higher taining reactant is not important, that is it can be a molar ratios of tin to platinum, that is, the disclosed liquid or solid. The main other criteria is that it is capa catalysts contain molar ranges of tin to platinum of ble of being dispersed or dissolved in the reaction mix 100:1 or higher. ture so that the carboxylated product is formed. Illus E. Molar Ratio of Calalyst to Olefin Substrate 45 trative suitable hydroxyl-containing co-reactants in Experimental work indicates that a molar ratio of 10 clude water, primary or secondary alcohols including to 500 moles of olefin per mole of the palladium cata methanol, ethanol, n-propanol, n-butanol, isopropanol, lyst complex can be employed where alpha olefins as cyclohexane, n-dodecanol, phenol and substituted phe typified by 1-octene, are used as the substrate. Much nols, substituted alcohols such as 2-chloroethanol, and lower ratios (i.e. less than 10 moles of olefin substrate 50 polyols including glycol, propylene glycol, per mole of palladium) are not harmful but are eco glycerol, sorbitol and the like. To produce the free acid nomically unattractive. For this reason, as documented by this process water must be used as the hydroxyl-con by Table 3, ranges from 10 to 500 moles of olefin per taining reactant. To produce the esters one or more mole of palladium(II) catalyst composition are pre paraffinic or aromatic alkanols, glycols and/or polyols ferred. 55 must be employed as the hydroxyl-containing paraf F. Experimental Conditions Required for Carboxyl finic reactant. ation v The amount of water or hydroxyl-containing paraf The rates of carboxylation of typical a-olefins are finic reactant used is based upon the concentration of dependent upon the temperature, the pressure of car the alpha-olefin to be converted to the carboxylate bon monoxide, and the concentrations and choices of 60 product. For maximum product yields, at least a stoi palladium catalyst and alpha-olefin employed. Again chiometric quantity of “hydroxyl' reactant should be using 1-octene as a typical alpha-olefin, and 10 present (as stated above) dependent upon alpha-olefin (CH)NSnCla-PdCl2P(C6H5)3) as a representative concentration. This includes water as well as the alco catalyst, an operable temperature range is at least 25 hols, glycols and polyols. to 120°C or more. 65 The favored and sole suitable reactant for producing Superatmospheric pressures of at least 100 psig are the free acid is water; the favored hydroxyl-containing required for substantial conversion of the alpha olefin reactant being the lower alkanols, particularly those to the linear fatty (carboxylic) acid or ester. contaning 1 to 12 carbon atoms. 3,968,133 7 8 I. Carbon Monoxide Environment unreacted olefin and excess alcohol and fractionally Insofar as can be determined, the best selectivities distilled at 2-4 mm of mercury to recover the methyl and conversions of alpha-olefins to linear fatty acids nonanoates shown below. Gas chromatographic can be obtained within a reasonable time by using a (G.C.) analysis indicates the following conversion, substantially carbon monoxide gaseous atmosphere. selectivity and yield expressed in molar percentages. However, particularly in continuous operation, the carbon monoxide may be used in conjunction with Octene Conversion 9% from about 0 to 30% by volume of one or more inert Ethyl Nonanoate Selectivity** 83% gases such as nitrogen, argon, neon and the like without Total Yield of Ethyl Nonanoates' 84% 10 experiencing a substantial decrease in yield and selec * A mixture of cthy nonanoate with somc cthyl 2-mcthyloctanoate and cthyl tivity. 2-ethylheptanoatc. J. Selectivity **Calculated from: Total cthylnonanoate/total cthy C. acid cster. Selectivity as described herein is the efficiency in catalyzing a desired carboxylation reaction relative to PART B other undesired carboxylation reactions. In this in 5 The procedure of Example 1A is followed substan stance carboxylation to the linear fatty acid or ester tially as described above, except that in separate runs derivative is the desired conversion. Selectivity is usu the ethanol coreactant is substituted by methanol, n ally expressed as a percentile and is calculated by de propanol, n-butanol and n-pentanol. In all instances termining the amount of linear carboxylated product comparable octene conversions and linear nonandate formed, divided by the total amount of carboxylated 20 ester selectivitives are obtained. products formed and multiplying the quotient obtained PART C by 100. Again the procedure of Example 1A is substantially K. Conversion followed, except that the following hydroxyl-containing Conversion as defined herein is the efficiency in con co-reactants are substituted for ethanol as the hydrox verting the olefin charge to nonolefinic products. Con 25 yl-containing co-reactant. version also is expressed as a percentile and is calcu 2-chloroethanol, lated by dividing the amount of olefin consumed during 1-decanol, carboxylation by the amount of olefin originally ethylene glycol, charged and multiplying the quotient by 100. propylene glycol, L. Yield 30 1-dodecanol, Yield as defined herein is the efficiency in catalyzing phenol and the desired carboxylation reaction relative to other dipropylene glycol. undesired reactions. In this instance carboxylation to In all instances comparable conversions of 1-octene fatty acid or ester derivative is the desired conversion. to the linear esters are obtained. Yield is usually expressed as a percentile, and is calcu 35 lated by determining the total amount of carboxylated EXAMPLES 2 TO 15 product formed, divided by the amount of alpha-olefin THE CARBOXYLATION OF 1 -OCTENE TO ETHYL charged and multiplying the quotient obtained by 100. NONANOATE - EFFECT OF WARYING THE M. Identification Procedures 40 PALLADIUM CATALYST COMPOSITION Identification procedures, where applicable, are by In these examples the carboxylation of 1-octene is one or more of the following analytical procedures - carried out in accordance with the procedure of Exam gas chromatograph (g.c.) infrared, nuclear magnetic ple 1A, in the presence of various ligand-stabilized resonance. Unless otherwise specified all percentages palladium (II) complexes dispersed in quaternary am are by weight rather than volume and all temperatures 45 monium, phosphonium and arsonium salts of trihalos are in centigrade rather than fahrenheit. tannate(II) and trihalogermanate(II), under constant Having described the inventive process in general temperature, pressure and substrate-to-catalyst molar terms, the following examples are submitted to supply ratio conditions. As can be seen from the data in Table specific and illustrative embodiments. I, a variety of ligands cane used to stabilize the palladi EXAMPLE 1. 50 um(II), including ligands with phosphorus and arsenic donor atoms bonded to alkyl, aryl and substituted aryl PREPARATION OF ETHYLNONANOATE BY THE groupings. Likewise, the quaternary ammonium, phos CARBOXYLATION OF 1-OCTENE phonium and arsonium salts may contain nitrogen, Part A phosphorus or arsenic atoms bonded to various alkyl, To a degassed sample of 1-octene (400 mmole) and 55 aryl, substituted aryl or substituted alkyl groups, and ethanol (400 mmole) contained in a reactor equipped mixtures thereof, in combination with both the tri for pressurizing, heating, cooling and means of agita chlorostannate(II) and trichlorogermanate(II) anions. tion is added under a nitrogen environment, tetraethyl Of the twelve palladium catalyst compositions exem ammonium trichlorostannate(II) (40 mmole) and bis plified in Table I, the best 1-heptene conversions and (triphenylphosphine) palladium(II) chloride (4.0 60 ethyl nonanoate yields are obtained with the bis(tri mmole). The reactor is sealed, deoxygenated with a phenylphosphine)palladium(II) chloride and bis(tri-p- purge of nitrogen, and pressurized under carbon mon tolylphosphine)palladium(II) chloride complexes dis oxide (1500 psig) while heating the agitated mixture persed in tetraethylammonium trichlorostannate(II) between 80' and 95°C for 3-6 hours. At the end of this salt (Examples 2 and 3). Each of the catalyst composi time the reaction is terminated by discontinuing the 65 tions of Examples 2 through l l (inclusive) show supe flow of carbon monoxide, cooling, and venting the rior performances compared with the analogous plati reactor. The crude ester product is filtered, distilled num catalyst, under reduced pressure (30 cm of mercury) to remove 3,968,133 9 10 disclosed by Parshall in U.S. Pat. No. 3,657,368, and ation conditions, where the applied Co pressure is 1500 similar platinum complex compositions. (See Examples psig (102 atm) versus 400 atm disclosed by Parshall, 14 and 15) only trace amounts of ethylnonanoates were obtained. TABLE 1. ETHYL NONANOATE SYNTHESIS FROM -OCTENE-CATALYST COMPOSITION SUDES OCTENE ETHYL. C. ACD ESTER EX. CATALYST-COMPOSITION CONV (%). SELECTIVITY(%)" YIELD (MOLE %) 2 101 (C.Hs),N)ESnCla)-PdCl2P(p-CHCH)al, 80 85.6 87 3 10 (CH)NSnCla-PodCP(CH) 83 86.3 83 4 5 ICH (CH)aP) SnClal-PdCl P(CH)al 70 873 67 5 10(n-CH)NSnCla-PodClP(CH) 66 78.8 63 6 5 (CH)As SnC-PdCP(CH) 55 69.8 35 7 5 (C.H.) NISnCl-PdCl(P(CH) 22 58 19 8 10 (CH),N) SnCla)-PaCl(P(p-CHO.C.H.) 60 85.8 48 9 10 (CHs).NSnCla-PodCl2(CH3)2C6Hs). 35 87.4 33 10 5 (C.H.)N) (GeCla)-PdCl2(P(C6Hs)a), 70 84.3 62 l 5 (CH)N(GeCla-PdCl As(CH) 20 85.2 15 2 10 (CH)N(SnCl)-PdCl P(CHs), 5 89.0 3.6 13 i0 (C2H5)N(SnC-PdCl2(AsOCHs), 2 92.5 16 4. 10 (CH), NISnCl)-PtCl(P(C6H5) 2.7 92 5 10 (CH).NSnCla-PtCl(As(CH) 2 88 . "All runs made at: 1500 psig CO; 85°C; 7 hr. 1-octene)/Pd = 100,01-octenc)/(ethanol)=l "Primarily a mixture of cthylnonanoate with some cthyl 2-methyl octanoate and cthyl 2-cthyl heptanoate Calculated from: total cthylnonanoate/total cthy C. acid estcr "A standard catalyst described by Parshall in U.S.P. 3,657,368

25 It may also be noted that the palladium catalyst in the EXAMPLE 16 TO 22 absence of stabilizing ligands (Example 22) viz. THE CARBOXYLATION OF 1 -OCTENE TO ETHYL (CH)4NSnCla-PodCl NONANOATE - EFFECT OF USING OTHER yields only trace amounts of nonanoate esters, under TRANSITION-METAL CATALYST conditions where ligand-stabilized palladium(II) cata COMPOSITIONS 30 lysts such as exemplified in Examples 1 to 11 give good In these examples, the carboxylation of 1-octene is yields of desired esters. carried out in accordance with the procedure of Exam The preceding data obtained on pages 19 and 20 of ple 1A, but using as catalysts a variety of transistion this application were run to refute or confirm Parshall's metal salts, particularly platinum, nickel, ruthenium, allegation that any of the transition metals having iron, cobalt and molybdenum salts and complexes dis 35 atomic numbers falling within the groups having an persed in a typical quaternary ammonium salt of tri atomic number of 22-28, 40-46 or 72-79 could be chlorostannate(II), namely N,N,N,N-tetraethylam used as the catalytic entity in the carboxylation of al monium trichlorostannate(II). As can be seen from the pha-olefins. (See Col. 2, lines 21-32). As the above data in Table 2, the following catalyst compositions, mentioned data of pages 19 and 20 confirm: Molybde disclosed previously in U.S. Pat. No. 3,657,368, proved 40 num (atomic number 42) catalysts were inactive for to be inactive for 1-octene carboxylation under the carboxylation, as were ruthenium (Atomic Number standard experimental conditions employed in Exam 44), cobalt (Atomic Number 27), Iron (Atomic Num ples l to 13 for the active palladium catalysts: ber 26), nickel (Atomic Number 28) and platinum (CH)NSnCl-MoCls (Atomic Number 78). Since all of these typical transi (CH3)4NSnCla-CoCl2 45 tion metals disclosed by Parshall unexpectedly proved (CH3)NSnCl-NiCl2 to be completely ineffective as carboxylation catalysts, (CH)NSnCl-FeCl the alleged broad disclosure of Parshall as set forth in TABLE 2 ATTEMPTED ETHYL NONANOATE SYNTHESIS FROM OCTENE USING OTHER TRANSiTION METAL COMPLEXES OCTENE ETHYLCs can Ester EXAMPLE CATALYST COMPOSITON CONV (%) YIELD (MOLE 9%) 6 10 (CHs)..NSnCl-K2PtCl 1 Trace 7 0 (CHs).NSnCla-RuCl2P(C6Hs). 1. None 18 10 (CH)NSnCla-CoCl None 19 10 (CH)NSnCl-FeCl None 20 10 (CH)NSnCla-NiCl, 1 None 2 10 (CHs)..NSnCla-MoCls l None 22 10 (CH)N)SnCla-PdCl Trace "All runs madc at 1500 psig CO, 85°C, 7 hr., 1-octene)/Mle 100, ( 1-octenel/ethanol)=1 Similarly, the ligand-stabilized ruthenium(II) com plex, Rucle(P(C6H5)3), gave no acid ester under these conditions (Example 17). The platinum(II) chloride catalyst shown in Example 16, viz. 65 (C2H5)4N SnCl-PtCl his patent should not be used to reject applicant's is similar to that disclosed in U.S. Pat. No. 3,657,368, claims drawn to specific palladium (Atomic Number Example 27. However, under our standard carboxyl 46) catalyst complexes. 3,968,133 11 12 1. The crude liquid product containing the liquid EXAMPLES 23 to 30 ester is filtered from the crystalline melt. THE CARBOXYLATION OF OCTENETO 2. The crude ester of (1) is flash distilled under re METHYL NONANOATE . EFFECT OF VARYING duced pressure (1 cm to 75 cm of mercury) to strip THE OPERATING CONDITIONS off unreacted octene and methanol. In these examples, using the same techniques of Ex 3. The ester from step (2) is extracted three times ample 1A, together with the same palladium catalyst, with excess petroleum ether to precipitate the dis (CH)NSnCl-PdCl2P(CH), and the same a solved catalyst melt. -olefin charge, 1-octene, the effect of varying the car 4. The ether extract is flash distilled under reduced boxylation temperature, pressure of CO, and reactant 10 pressure (1 cm to 75 cm of mercury) to recover mole ratios has been examined. The results are summa methylnonanoates, and rized in Table 3. It is evident from the data that carbox 5. The recovered melt from steps (1) and (3) is com ylation of 1-octene to methyl nonanoate may be bined with additional 1-octene and excess metha achieved with this catalyst system over a wide range of nol. Table 4 documents the results obtained. TABLE 4 CARBOXYLATION OF OCTENE TO METHY NONANOATE - CATALYST RECYCLE STUDY - CATA- OCTENE LOUID METHYL C, ACID ESTER SOLATED LYST ESTER EXAMPLE CYCLE CONVER- YIELD(%) SELECTIVITY (%) YIELD(MOLE PURITY SION(%) %) 3. I 80 85 86.3 85 95 32 80 88 86.5 81 95 33 I 74 94 89.5 72 96 34 V 29 96 90.6 25 98 "Run Conditions: 1500 psig CO; 85°C, 10 hr., (Sn/Pd=9.6; 1-octene, Pd =92; Methanol. 1-octenesel.9. A mixture of methylnonanoate with some Incthyl 2-methyl octanoate and methyl 2-cthylheptanoate. Selectivity to incar methylnonanoate based on total methylnonanoateftotal mcthy Cester. Yield based on octenc charged. conditions, as follows: As can be seen from the results presented in Table 4, a. Molar ratios of tin salt to palladium complex rang 30 methylnonanoate ester yields remain essentially equiv ing from 5:1 up to 100:1, respectively. alent over the first three cycles of the b. Initial molar ratios of ov-olefin to palladium catalyst (CH)4NSnCls-PodClP(CH) catalyst, but some ranging from 10:1 up to 500:1. deactuation is evident in the 4th cycle. On the other c. Operating temperatures of 25 to 120°C. hand, the selectivity to linear methylnonanoate im d. Superatmospheric pressures of at least 100 psigo 35 proves steadily with successive cycling. CO. In a similar experimental series to Examples 28 TABLE 3 CARBOXYLATION OF OCTENE TO METHYL NONANOATE - EFFECT OF WARYING OPERATING CONDITIONS Sn)/Pd -OCTENE/Pd) CO METHYL C, ACID ESTER EX. MOLE MOLE RATO TIME (hr) TEMP. (°C) PRESSURE(P- SELEC- YIELD(MOLE%) RATIO SIG) TIVITY(%) 23 OO 40 8 8O 2000 9.0 24 24 45 O6 8 95 2000 79.8 73 25 5 46 O 95 2000 75.8 93 26 O O 2 75 2000 82 90 27 O SOO 12 95 2000 91.2 30 28 10 O) 12 25 500 90.8 O 29 O OO 2 20 1500 80 43 30 10 OO 12 80 OO 82 O "All runs carried out with at lcast stoichiometric amounts of CO and methanol present with respect to 1-octene charged. A mixture of methylnonanoate with some methyl 2-methyloctanoate and methyl 2-ethylheptanoate. Sclectivity to linear methylnonanoate calculate from total methylnonanoateftotal methyl C acid ester. Yield of total ester based on 1-octenc charged. through 31, using the same procedures and the same EXAMPLES 31 TO 34 1-octene, methanol charge stocks, the platinum cata 55 lyst (C2H5)NSnCls-PtCl(P(C6H5)3) was tested for THE CARBOXYLATION OF 1 -OCTENE TO catalyst recycle capability. Yields of methylnonanoate METHYL NONANOATE - CATALYST RECYCLE were less than 2% for each of the four catalyst cycles. STUDY - I EXAMPLES 3.5 TO 40 Using the general procedure of Example 1A, addi tional runs were made with a 1-octene, methanol 60 THE CARBOXYLATION OF 1-OCTENE TO ETHYL charge mixture and the catalyst system: NONANOATE - CATALYST RECYCLE STUDY - (CH)NSnCl-PodCl2P(C6H5)2 I However, four(4) different fractions of 1-octene were Using the general procedure of Example 1A, addi carboxylated separately in these examples using a sin tional carboxylation runs are made with six fractions of gle sample of Pd catalyst. Recovery of the product 65 1-octene, ethanol charge mixture, and a single sample methyl nonanoate after each cycle by an ether extrac of the catalyst (CH5)NSnCla-PdCl2(P(C6Hs). tion technique, and recycle of the palladium catalyst, Here, however, the product ethyl nonanoate ester is were carried out as follows: recovered after each cycle by a vacuum distillation 3,968,133 13 14 technique, and the palladium catalyst recycled as foll ation reactions for the synthesis of linear fatty acids and lows: esters rom a-olefin stocks. 1. The crude liquid product containing the liquid Among the more important gains over similar types ester is filtered from the crystalline melt. of palladium catalysts, such as (C6H5)3Plapdcle 2. The crude liquid product of (1) is subject to distil- 5 SnCl*, used with conventional liquid solvents, are the lation under reduced pressure (1 cm to 75 cm of greater ease in separating the product acids or esters mercury) to strip off unreacted octene and ethanol. from the reaction medium, the smaller bulk of the 3. The partially purified ester is subject to fractional reaction mixture, and the greater thermal stability im distillation in vacuo (1 to 50 mm of mercury). parted to this type of ligand-stabilized palladium cata 4. The recovered melt catalyst from steps (1) and (3) 10 lyst. is combined and recycled with additional equimo *See U.S. Pat. No. 3,700,706 lar, 1-octene, ethanol mixture. In order to gain better perspective insofar as the TABLE 5. CARBOXYLATION OF 1 -OCTENE TO ETHYL NONANOATE- CATALYST RECYCLE STUDY - if CATA- OCTENE OUID ETHYL C, ACID ESTER SOLACED LYST ESTER EXAMPLE CYCLE CONVER- YIELD(%) SELECTIV- YIELD(MOLE 9%) PURITY(%) SION(%) ITY (%) , 35 80 78 710 84 99 36 I 80 OO 75.9 88 99 37 70 00 89.7 69 99 38 IV 53 96 90.0 52 99 39 V 32 100 9.2 3. 99 40 V l4 OO 92.0 14 99 "Run Conditions: 1500 psig CO; 85°C; (Sn)/Pd)=10; 1-octene)/Pd)=63; (cthanol)/(1-octence=1.0 scope or metes and bounds of the subject invention are As can be seen from the results in Table 5, the concerned, a careful reading of the claims which fol PdCl2P(CH) complex dispersed in lows is recommended, in conjunction with the preced ((CH3)4NSnCls remains active for 1-octene carboxyl ing specification. ation over at least six cycles, without the need to mod 30 What is claimed is: ify the catalyst in any way. Once again, the selectivity 1. A process for preparing linear, carboxylic (fatty) to linear ethyl nonanoate improves with successive acids and their ester derivatives through the catalytic cycling. s reaction of alpha-olefins containing from about 3 to EXAMPLES 4 TO 44 about 40 carbon atoms, carbon monoxide and hydrox 35 yl-containing co-reactants by: THE CARBOXYLATION OF I-HEXENE TO ETHYL a. admixing each molar equivalent of alpha-olefin to HEPTANOATE CATALYST RECYCLE STUDY - III be carboxylated with at least a stoichiometric Using the general procedure of Example 1A, further amount of hydroxyl-containing co-reactant se carboxylation runs are made with four (4) fractions of lected from the group consisting of water, alkanols, 1-hexene, ethanol charge mixture, and a single sample 40 diols, containing 1 to 12 carbon atoms, of the catalyst (CH)NSnCla-PdCl2P(p- chloroalkanols containing 1 to 4 carbon atoms, and CH-CH)). The product ethyl heptanoate ester is at least a catalyst amount of ligand-stabilized pal recovered after each cycle by the vacuum distillation ladium(II) halide complex dispersed in quaternary technique described in Example 32. ammonium, phosphonium and arsonium salts of As can be seen from the results presented in Table 6, 45 trihalostannate(II) or trihalogermanate(II) se the catalyst (C2H5)4NSnCls-PdCl2P(p-CH-CH)al lected from the group consisting of: provides an excellent means for the multiple synthesis ((CH3)4N](SnCl4]-PdCl2(P(p-CH3CH)al, of heptanoate esters from 1-hexene. (C2H5)4NSnCla-PdCl2P(C6H5)3) TABLE 6 CARBOXYLATION OF -HEXENE TO ETHYL HEPTANOATE - CATALYST RECYCLE - III CATA- ETHYL C, ACID ESTERS SOLATED LYST ESTER EXAMPLE CYCLE SELECTIV- YELD (MOLE PURITY (%) ITY(%) %) 4. I 67.3 95 99 42 I 718 94 99 43 I 86.6 70 99 44 V 90.8 51 99

As established by the preceding examples and Ta bles, numerous advantages accrue from the practice of this invention wherein certain empirically derived cata lysts consisting of ligand-stabilized palladium(II) com 65 plexes dispersed in quaternary ammonium, phospho nium and arsonium salts of trihalostannate(II) and trihalogermanate(II), have been employed in carboxyl 3,968,133 16 wherein the molar ratio of quaternary tin(II) or ger 6. A process for preparing linear, carboxylic (fatty) manium(II) salt to palladium is between 2 to 10 to 1, in acids and their ester derivatives through the catalytic a substantially oxygen-free environment, in the present reaction of alpha-olefins containing from about 3 to of at least a stoichiometric amount of carbon monoxide about 40 carbon atoms, carbon monoxide and hydrox with respect to olefin, at superatmospheric pressures of 5 yl-containing co-reactants by: carbon monoxide of at least 100 psig, to form a pressur a. admixing each molar equivalent of alpha-olefin to ized reaction mixture; be carboxylated with at least a stoichiometric b. heating said reaction mixture at temperatures amount of hydroxyl-containing co-reactant se ranging from about 25 to 120°C for a time suffi lected from the group consisting of water, alkanols, cient to substantially carboxylate said alpha-olefin O alkane diols, containing 1 to 12 carbon atoms, to the corresponding carboxylic (fatty) acid or chloroalkanols containing 1 to 4 carbon atoms, and ester, and at least a catalytic amount of ligand-stabilized pal c. isolating said carboxylated products prepared ladium(II) halide complex dispersed in quaternary therein. ammonium, phosphonium and arsonium salts of 2. The process of claim 1 wherein the reaction mix 15 trihalostannate(II) or trihalogermanate(II) se ture contains as the hydroxylated co-reactant water, lected from the group consisting of: and the carboxylated product is a linear fatty (carbox (CH)As SnCla-PdCl2P(C6H5)32 ylic) acid. (C2H5)N GeCla-PdCl2(AsOCH3)2, and (C2H5)4NSnCls-PodCl2(AsOCH5)2 3. The process of claim 1 wherein said catalyst com 20 wherein the molar ratio of quaternary tin(II) or ger plex is preformed prior to the formation of the reaction manium(II) salt to palladium is between 2 to 10 to 1, in mixture. a substantially oxygen-free environment, in the pres 4. The process of claim 1 wherein said catalyst com ence of at least a stoichiometric amount of carbon plex is prepared in situ by adding as separate compo monoxide with respect to olefin, at superatmospheric nents the ligand-stabilized palladium halide complex 25 pressures of carbon monoxide of at least 100 psig, to and the quaternary ammonium, phosphonium, and form a pressurized reaction mixture; arsonium salt of trihalostannate(II) or trihaloger b. heating said reaction mixture at temperatures manate(II). ranging from about 25 to 120°C for a time suffi 5. The process of claim 1 in which the alpha-olefin to cient to substantially carboxylate said alpha-olefin be carboxylated is 1-octene, the hydroxylated co-react 30 to the corresponding carboxylic (fatty) acid or ant is ethanol, and the palladium catalyst complex is ester, and (CH5)N SnCla-PodCl P(CH) c. isolating said carboxylated products prepared and the major linear fatty acid ester product is ethyl therein. nonanoate. ck k k -k sk 35

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65 UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTION PATENT NO. : 3,968, l33 DATED : July 6, 1976 INVENTOR(S) : John F. Knifton It is certified that error appears in the above-identified patent and that said Letters Patent are hereby COrrected as shown below:

Column 2, line l8: "sufficient" should read --insufficient-- Column !, line 46: "environmenrt" should read --environment-- Column 6 line 7; " (60)" should read -- (CC)-- O Column 8, line l9: "nonandate" should read --nonanoate-- Column 9 line 33: "transistion" should read --transition-- O Column ll, line 42: "catalyst" should read --catalytic-- Column lb line 3: "present" should be --presence-- eigned and Sealed this C) twelfth Day of July 1977 SEAL Attest.

O - RUTH C. MASON C. MARSHALL D ANN Attesting Officer Commissioner of Patents and Trademarks

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