Hydrogenation of unsaturated fatty acids to unsaturated fatty alcohols: I. Study of Cu and Cd oleates as catalysts

The catalyst system containing copper and cadmium oleates as used in selective hydrogenations was analyzed. The reddish brown reaction mixture as such and after precipitation by alcohol was subjected to polarographic, spectroscopic, x-ray and electron-microscopic analysis. The conclusion drawn was that the mixture is a heterogeneous system. From an electron micrograph it was observed that the average particle size is 48 Å. It was also possible to determine the mean degree of oxidation of copper in the precipitate, the results indicating that the copper is in its metallic state. Cadmium is present as cadmiumoleate, which stabilizes the copper colloid during the reaction.     

Hydrogenation of unsaturated fatty acids to unsaturated fatty alcohols: III. Comparison of different soap catalyst systems

Copper oleate and cadmium oleate catalysts have been replaced by other metal compounds. Silver was the only metal which could be substituted for copper in the ratio range studied. Using nickel oleate, the degree of saturation of the double bond decreased with increasing cadmium oleate concentration. No comparable substitute was found for Cd. The composition of the final components is influenced by the use of a paraffinic solvent, which also has an effect on the saturation of the double bond. An explanation is given for the behavior of the catalyst when the reaction is not selective and is carried out in a paraffinic solvent. The catalytic system Ag/Cd soaps was also studied kinetically and analytically. The results show that the mechanism of the reaction using silver soap is identical with the one using copper soap.     

Homogeneously catalysed hydrogenation of unsaturated fatty acids to unsaturated fatty alcohols

The use of copper and cadmium oxides or soaps as catalysts for the hydrogenation of unsaturated fatty acids to unsaturated fatty alcohols has been investigated. It is shown that copper soaps homogeneously activate hydrogen. When copper and cadmium oxides are used as catalysts, they react with the acid under formation of a homogeneous soap solution. A continuous reaction system for the preparation of unsaturated fatty alcohols by hydrogenation under the influence of copper and cadmium soaps is described.     

Hydrogenation of unsaturated fatty esters with copper-chromite catalyst: Kinetics,mechanism and isomerization

Hydrogenation of linolenate with copper chromite produced a large amount of conjugated diene and minor amounts of nonconjugatable dienes. The double bonds in conjugated dienes and monoenes were scrambled all along the chain. This product distribution can be explained if it is assumed that conjugation of the double bonds is followed by hydrogenation. In competitive hydrogenation, fatty esters with conjugated double bonds were reduced preferentially over fatty esters with methylene-interrupted double bonds. Isomerization of conjugated double bonds (geometric and positional) occurred more rapidly than reduction. Reduction of conjugated double bonds in the presence of deuterium resulted in a majority of the products containing no deuterium. Most of the added deuterium was incorporated into the unreacted material. Mechanisms are proposed to account for the products formed during the hydrogenation of linolenate, linoleate and their isomers. One of 10 papers to be published from the Symposium “Hydrogenation,” presented at the AOCS Meeting, New Orleans, April 1970. No. Utiliz. Res. Dev. Div., ARS, USDA.     

Reactions of unsaturated fatty alcohols. VI. Guerbet reaction of soybean and linseed alcohols

Summary Both soybean and linseed alcohols were heated with potassium hydroxide and boric anhydride at 300°C. for 3 to 4 hrs. Products obtained under these conditions contained no unreacted starting alcohol, and each one appeared to be a mixture of condensed alcohols with average molecular weights of 720–860. Infrared spectroscopic studies and chemical analyses indicate that little or no ethers, esters, or carbonyl compounds were present in the final product from either alcohol. Such reactions as thermal cross-linking of the unsaturated side chains probably account for higher molecular weight products than those obtained in the Guerbet reaction of stearyl alcohol. Condensed alcohols from soybean and linseed alcohol were esterified with acrylic, sorbic, maleic, and soybean fatty acids to yield products with low acid numbers. Preliminary experiments demonstrated that these alcohols and their esters showed promise as materials for protective coatings. Films from these alcohols and esters were cast from toluene containing a cobalt naphthenate drier and were baked at 150°C. for 1 hr. or at 200°C. for 20 min. All of the baked films were hard to moderately hard and showed good resistance to aqueous alkali and organic solvents. In general, films from soybean condensed alcohol and its esters were harder than those from linseed condensed alcohols, but the linseed films were superior in alkali and solvent resistance. A soybean fatty acid ester of soybean condensed alcohol air-dried to a soft film in 3 days. Presented at the 49th Annual Meeting, American Oil Chemists' Society, April 21–23, 1958, Memphis, Tenn.     

Reduction of unsaturated fatty acids and fatty alcohols with diimide from hydroxylamine-ethyl acetate

Hydroxylamine has been recently found to react with ethyl acetate to generate diimide in situ. This reaction was used to reduce 10-undecenoic, oleic, linoleic, stearolic, concentrates of ricinoleic, cyclopentene and cyclopropene fatty acids (FA), dehydrated castor oil FA, 10-undecen-1-ol, oleyl alcohol and castor fatty alcohols. Unsaturated FA and their corresponding alcohols reacted in a similar manner. Terminally unsaturated, cyclopropene and cyclopentene FA were more reactive than oleic acid, which, in turn, was more reactive than hydroxymonoenoic acids. Conjugated dienoic FA reduced faster than nonconjugated dienoic acids. Partial hydrogenation using this reagent is particularly advantageous in determining geometry and the position of double bonds in the polyunsaturated FA, as it can be carried out in the absence of oxygen or oxidizing agents unlike hydrazine reductions.     

Kinetics of reaction of ethylenediamine and dimeric fatty acids

Kinetic studies were carried out on the reaction between ethylenediamine and dimeric fatty acids in melt phase. The reaction was performed at 124, 130, 145, 160, 174, and 190°C and followed by determining the acid value of the product. The polyamidation reaction was found to be of overall second order with an activation energy of 18.2 kcal/g mol up to 90% conversion and of overall third order with an activation energy of 16.4 kcal/g mol above 90% conversion.     

Reactions of unsaturated fatty alcohols. XIII. copolymers of unsaturated fatty vinyl ethers and cyclic monomers

Conjugated linseed, conjugated soybean, and nonconjugated linseed vinyl ethers were copolymerized with various cyclic comonomers. The comonomers used were dihydroabietyl, cyclohexyl, 5-norbornene-2-methyl, di- and tetra-hydrodicyclopentadienyl vinyl ethers, and cyclo-and methylcyclo-pentadiene. All copolymers containing a cyclic comonomer gave baked films that are distinctly superior to unmodified drying oils or vinyl ether homopolymers in hardness and alkali resistance. Several of these copolymers air-dried overnight to moderately hard, wrinkle-free films. The improvement in hardness and alkali resistance may be caused by the steric effects of the cyclic comonomers. These hold the fatty side chains apart thus increasing the proportion of intermolecular to intramolecular crosslinking. Presented in part at the spring meeting, American Oil Chemists' Society, St. Louis, Mo., May 1–3, 1961. A laboratory of the Northern Utilization Research and Development Division, Agricultural Research Service, U.S.D.A.     

Reactions of conjugated fatty acids. III. Kinetics of the Diels-Alder reaction

Summary The kinetics of a Diels-Alder-type reaction between diethylazodicarboxylate andt,t-9,11-octadecadienoic acid has been studied in various solvent systems and with acidic catalysts. The rate of the reaction was found to vary as follows: a) the reaction rate is faster in polar solvents than in nonpolar solvents; b) addition of acidic catalysts to nonpolar solvents increases the rate of the reaction, and acidic catalysts appear to have no effect on the rate of reaction in polar solvents; c) when compatibility can be maintained, addition of water to polar solvent systems appears to increase the reaction rate in proportion to the amount of water added. The reaction follows second-order or pseudo second-order kinetics. Probably it is more complex than the over-all reaction kinetics indicate. Certain reactions were studied at two temperatures, and information on activation energy of the reaction has been obtained. Presented at fall meeting, American Oil Chemists’ Society, Philadelphia, Pa., Oct. 10–12, 1955.     

Reactions of unsaturated fatty alcohols. II. Polymerization of vinyl ethers and film properties of polymers

Summary Vinyl ethers of stearyl, soybean, and linseed fatty alcohols have been prepared and polymerized in solution in hydrocarbon or chlorinated solvents at temperatures down to −30°C. with several Lewis-acidtype catalysts. Stearyl polyvinyl ether was a white, waxy solid melting at 44°–50°C. while soybean and linseed polyvinyl ethers were colorless, viscous liquids. Molecular weights of these polymers range from 1,500 to 15,000 and higher, depending on the conditions of polymerization. Films of soybean and linseed polyvinyl ethers containing driers were cast from toluene solution. Hard films were obtained with cobalt drier by baking at 150°C. while softer films were obtained under these conditions when lead driers were used. Soybean films containing cobalt drier and baked on Pyrex glass dissolved completely in 5% aqueous alkali. A fatty acid coresponding to the fatty alcohol side chain was isolated from this solution along with a material that appeared to be partially oxidized polyvinyl alcohol. Baked films of soybean polyvinyl ether with lead drier did not dissolve in alkali. Some improvement of alkali resistance was obtained with cobalt films by adding aromatic amines as antioxidants. Soybean polymer films containing cobalt and baked on soft glass or metal surfaces were resistant to 5% aqueous alkali for at least three days. Soybean polyvinyl ether was emulsified with an equal weight of water, using ammonium salts of fatty acids as emulsifiers. Films were prepared from this emulsion that appeared to be continuous. Presented at the meeting of American Oil Chemists' Society, Chicago, Ill., September 24–26, 1956. Since the Department of Agriculture does not recommend the produets of one company over those of another, these names are furnished for information only.     

Addition of chlorine to unsaturated fatty acids and esters

Summary Methyl oleate, oleic acid, and ethyl linoleate were chlorinated with elemental chlorine at temperatures near −20°C. Approximately quantitative yields of the addition products were obtained, with little or no concurrent substitution. The products prepared in this manner had not previously been reported in the pure state. Two new compounds, ethyl tetrachlorostearate and tetrachlorostearic acid, were prepared. Methyl dichlorostearate was found to distil with no apparent decomposition at 190–200°C. under pressures below 1 mm. Removal of the chlorine atoms required more drastic conditions that removal of bromine atoms from the same positions and was accompanied by complicating side reactions. Journal Paper No. 755 of the Purdue University Agricultural Experiment Station, Lafayette, Ind.     

Kinetics and mechanism of oligomerization of cardanol using acid catalysts

The kinetics and mechanism of oligomerization of cardanol over acid catalysts were studied. GPC results showed the formation of a mixture of oligomers such as dimer, trimer, tetramer, etc. IR spectra of the products of oligomerization showed a decrease in the intensity of the double bond absorption band at 1630 cm^?1 and the disappearance of terminal vinyl bands at 895 cm^?1 and 907 cm^?1. ¹H NMR spectra showed drastic changes in the unsaturated proton resonance signals at 5.5δ with respect to saturated protons at 0.2–2.5δ. The ratio of resonance integrals of unsaturated to saturated protons decreased from 1 : 6.5 to 1 : 20 after oligomerization. GPC studies showed that the rate of formation of the dimer, trimer, tetramer, etc. follow an identical path and that the individual oligomers are formed in the same weight percentage at any time during the reaction. A kinetic scheme is proposed to explain this phenomenon. Kinetic studies showed that the oligomerization reaction follows first order kinetics with respect to the monomer concentration and the rate constant is K = 6.6 × 10^?5s^?1. A probable mechanism for the oligomerization of cardanol is proposed.     

Microbial conversion of linoleic and linolenic acids to unsaturated hydroxy fatty acids

The conversion of oleic acid to 10-hydroxystearic acid with resting cells ofNocardia cholesterolicum (NRRL 5767) has been previously reported. These same microorganisms also convert linoleic and linolenic acids to 10-hydroxy-12c-octadecenoic and 10-hydroxy-12c,15c-octadecadienoic acids, respectively. The reaction occurs best at 35°C and a pH of 6.5. Under optimum conditions, 75–80% of the unsaturated fatty acid substrate is converted to the corresponding hydroxy acid. The hydroxy products were characterized by gas chromatography, gas chromatographymass spectrometry, nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy. Other microorganisms that successfully converted these substrates include another strain ofNocardia cholesterolicum (NRRL 5768) andNocardia sp. (NRRL 5636). Presented at the 82nd Annual meeting of the American Oil Chemists’ Society, Chicago, IL, May 12–15, 1991.     

Kinetics and mechanism of hydrogenation of furfural on Cu/SiO2 catalysts

The hydrogenation/hydrodeoxygenation of furfural was studied on a Cu/SiO₂ catalyst at 230–290 °C. Detailed kinetics, density function (DFT) calculations, and spectroscopic studies were combined to investigate this reaction. A Langmuir–Hinshelwood model was found to fit the kinetic data well and provided the parameters of physical significance. The heat of adsorption (ΔH_ads) of furfural, derived from the fitting, was found to be significantly higher than those of furfuryl alcohol and 2-methyl furan. Activation energies for the conversion of furfural and furfuryl alcohol were both about 12 kcal/mol. DFT calculations and DRIFTS provided guidance about the nature of the surface species. Accordingly, the most likely species adsorbed on the Cu surface is suggested to be a top η¹(O)-aldehyde. DFT calculations of the reaction path show that the predicted energy barriers are of the same order as the experimental values and suggest that the hydrogenation of furfural can occur via either an alkoxide or ahydroxyalkyl intermediate.     

Production of cyclic fatty acids: Water as the reaction solvent

In an attempt to lower processing costs of producing cyclic fatty acids by a high-temperature alkali treatment, water was tested as the reaction solvent instead of ethylene glycol, previously used. Based on extensive tests in a high-pressure autoclave, saturated cyclic (cyclohexanoic) fatty acids were produced under economic reaction conditions, including a temperature of about 300C; a 4:1 solvent ratio and 50% excess sodium hydroxide catalyst. The lower yield of saturated cyclic fatty acids by the water process is more than offset by the fewer steps and reduced evaporation costs. Presented at the AOCS Meeting, Chicago, Ill., 1964. A laboratory of the No. Utiliz. Res. & Dev. Div., ARS, USDA.     

Reactions of unsaturated fatty alcohols. XIV. Preparation and properties of styrenated fatty vinyl ether polymers

New polymeric products have been prepared from conjugated linseed vinyl ether polymers and styrene. Up to 64% by weight of styrene can be incorporated by heating the preformed fatty vinyl ether polymer and monomeric styrene in an aromatic solvent. Primary factors influencing the course of the reaction were molecular weight and peroxide content of the starting vinyl ether polymer, reaction temperature, and type of solvent used. Formation of heterogeneous reaction products and gelation were encountered unless styrene was consumed in the reaction or removed. Films of these styrenated vinyl ether polymers show improved properties over the homopolymers previously studied. Baked films exhibit better gloss, color, and hardness; are more throughly cured; and show good flexibility and adhesion. Their resistance to 5% aqueous alkali is outstanding. The films also exhibit air-drying properties. Fatty vinyl ether polymers and copolymers have shown only limited compatibility with commericial resins. However, styrenated polymers are compatible with long oil alkyd, urea, epoxy, hydrogenated rosin, and polyurethane resins. Presented at AOCS meeting, St. Louis, Mo., May 1–3, 1961. A laboratory of the Northern Utilization Research and Development Division Agricultural Research Service, U.S.D.A.     

Kinetics of reaction of C36 dimeric fatty acids and ethylenediamine in solution

Kinetic studies were carried out on the reaction between ethylenediamine and C₃₆ dimeric fatty acids using benzyl alcohol as solvent. The reaction was performed at four different temperatures in the range of 160–190°C, and the products were analyzed for acid and amine values intermittently to follow the reaction. The fall in both the values was almost the same throughout the reaction. The kinetics was determined from the fall in acid value, and the reaction was found to be of overall third order and had an activation energy of 30.7 kcal mol^?1 (128.5 kJ mol^?1).     

Reactions of unsaturated fatty alcohols. V. Preparation and properties of some copolymers of unsaturated fatty vinyl ethers with lower alkyl vinyl ethers

Summary Soybean vinyl ethers derived from soybean alcohols were copolymerized with lower alkyl vinyl ethers,e.g., ethyl, butyl, isobutyl, 2-chloroethyl, 2-methoxyethyl, and 2-ethylhexyl, in methylene chloride at −30°C., using boron trifluoride etherate catalyst. Molecular weights ranging from 2,000 to 4,000 were obtained on these copolymers by cryoscopic measurements in cyclohexane. An analytical method, using infrared spectroscopy, was employed to determine the composition of the copolymers. The properties of each alkyl-soybean vinyl ether copolymer were studied at three molar compositions,e.g., 3∶1, 1∶1, and 1∶3. The products were water-white to amber viscous liquids and were soluble in aromatic, chlorinated, and gasoline type of solvents. Copolymers films were prepared under conditions that were shown to produce extensive degradation of some homopolymer films in order to magnify small differences in properties. These films were hard, wrinkle-free, and resistant to most common solvents, also were 20 to 500 times more resistant to 5% aqueous alkali than soybean vinyl ether polymer prepared under the same conditions. Copolymer films were baked on silver chloride plates and examined in the infrared. Oxidative degradation of the C−O−C ether linkage was observed in all copolymer films; however the 2-chloroethyl-soybean copolymer series was least susceptible to this degradation.     

Reactions of unsaturated fatty alcohols. I. Preparation and properties of some vinyl ethers

Summary A number of vinyl ethers of C₁₈ fatty alcohols have been prepared by reaction of the alcohol with acetylene at atmospheric pressure in the presence of a basic catalyst. Infrared spectroscopic data on long-chain fatty alcohols, their vinyl ethers, and related chemical derivatives have been obtained. Methods of analysis of long-chain vinyl ethers for vinyl group have been developed, namely, iodometric, hydroxylamine, and infrared methods. Preliminary experiments on the polymerization of long-chain vinyl ethers with ionic catalysts were carried out. Presented at fall meeting, American Oil Chemists’ Society, Philadelphia, Pa., Oct. 10–12, 1955.     

Hydrogenation of a menhaden oil: II. Formation and evolution of the C20 dienoic and trienoic fatty acids as a function of the degree of hydrogenation

To complement studies on monoethylenic fatty acids produced from the major polyunsaturated fatty acid (20:5A5,8,11,14,17) during hydrogenation of a menhaden oil of iodine value (IV) 159, the C₁₀ dienoic and trienoic fatty acid isomers of partially hydro-genated menhaden oils (PHMO) of IV 131.5, 96.5 and 85.5 were isolated by a combination of preparative gas liquid chromatography (GLC), mercuric adduct fractionation, and silver nitrate thin layer chromatography (AgNO₃-TLC). The 20:2 fatty acid methyl esters of the three PHMO samples were transformed to the corresponding alcohols and ozonized in BF₃-MeOH, followed by GLC analysis of the ozonolysis fragments. During the hydrogenation process, re-sidual ethylenic bonds in the 20:2 isomers tend to migrate both towards the carboxyl group and towards the methyl end of the molecule. The hydrazine reaction results revealed that thetrans ethylenic bonds in the 20:2 and 20:3 isomers were distributed all along the the carbon chain, but thecis ethylenic bonds were more localized in the Δ11,Δ14 and Δ17 positions of the preexisting major menhaden oil component 20:5Δ5,8,11,14,17. Iatroscan analyses on AgNO₃-chromarods revealed that, as a result of the hydrogenation process, almost half of the 20:2 isomers were non-methylene-interruptedcis, trans/trans, cis structures. Presented in part at the 73rd annual AOCS meeting, Toronto, 1982.