Production of fatty alcohols from fatty acids

Detergent-range alcohols from natural feedstock can be produced by high pressure hydrogenation of either methyl esters or fatty acids. The increasing quantities of fats and oils on the world market secure a reliable and economically priced material. Although fatty acid is an abundant worldwide commodity, most alcohol producers hydrogenate methyl esters, because direct hydrogenation of fatty acids is difficult as the catalyst is sensitive to acid attack. The process described here makes it possible to hydrogenate fatty acids directly to alcohols of high quality without prior esterification. The reaction takes place in the liquid phase over a fine-grained copper chromite slurry in a single reactor vessel. A special reactor design with an optimum arragement of the feeding nozzles causing an appropriate circulation of the reacting components inside the reactor facilitates the rapid “in situ” esterification reaction. This minimizes the free fatty acid concentration in the reactor to nearly zero. This results in a low consumption of catalyst. The most important advantages of the process are: direct feed of fatty acids of various origins, use of reasonably priced raw materials such as soapstock fatty acids and lower grade tallow acids, no process steps with methanol, and excellent economics. The process is industrially proven.     

Biodiesel processing and production

Biodiesel is an alternative diesel fuel that is produced from vegetable oils and animal fats. It consists of the monoalkyl esters formed by a catalyzed reaction of the triglycerides in the oil or fat with a simple monohydric alcohol. The reaction conditions generally involve a trade-off between reaction time and temperature as reaction completeness is the most critical fuel quality parameter. Much of the process complexity originates from contaminants in the feedstock, such as water and free fatty acids, or impurities in the final product, such as methanol, free glycerol, and soap. Processes have been developed to produce biodiesel from high free fatty acid feedstocks, such as recycled restaurant grease, animal fats, and soapstock.     

Hydrogenation of fatty acids

Catalytic hydrogenation is a vital process for both the edible fats and oil and the industrial fatty chemical industries. The similarities and differences between the fat and oil and fatty acid hydrogenations in equipment, processing conditions, and catalysts employed are of some importance since both are used in the various operations. Generally, the catalytic hydrogenation of fatty acids is carried out in corrosion-resistant equipment (316SS), whereas for fats and oils while 316SS is desirable, 304SS or even black iron surffice. The speed of hydrogenation varies radically with the content of impurities in both fat and oil and fatty acid feedstocks. Especially detrimental for both hydrogenations are soap and sulfur contaminants, proteinaceous materials left in the oils from poor refining, etc. Fatty acids from vegetable oil soapstocks are especially difficult to hydrogenate. Soybean-acidulated soapstock must usually be double-distilled for good results; cottonseed soapstocks frequently triple-distilled in order that they can be hydrogenated below iodine values of 1. Fatty acid hydrogenation effectiveness is measured by achieveing a low iodine value as fast and as economically as possible. Variables that influence hydrogenation effectiveness are reactor design, hydrogen purity, feedstock quality, catalyst activity and operating conditions.     

Methyl esters in the fatty acid industry

Methyl esters, derived from natural fats or oils, can be used as alternatives to fatty acids in the production of a number of derivatives. The derivatives that can be made from methyl esters include fatty alkanolamides, fatty alcohols, isopropyl esters, and sucrose polyesters. By using methyl esters as the raw materials, several benefits may be realized, such as, the ability to make higher purity finished products, the use of milder conditions during syntheses, and the need for less expensive materials of construction. In addition to the applications mentioned, methyl esters are being used increasingly in fractional distillations because they have lower boiling points and are less corrosive than fatty acids.     

Challenges to a mature industry: Marketing and economics of oleochemicals in Western Europe

Basic oleochemicals are produced by splitting and further reactions of oils and fats: fatty acids, glycerine, fatty acid methyl esters, fatty alcohols and amines. The last two are included in the list of oleochemical raw materials, primarily because of their importance in the preparations of further derivatives. The wide range of derivatives of oleochemical raw materials such as fatty alcohol ethoxylates, fatty alcohol sulfates, fatty alcohol ether sulfates, quaternary ammonium compounds and soaps are summarized. Oleochemicals such as fatty alcohols and glycerine from oils and fats have equivalents on the basis of petrochemicals. Using the customary terminology, petrochemical products are referred to as “synthetics.” The are included in the present discussion because in the application of oleochemical raw materials the origin of the material is often less important than the structure. Oleochemistry can be regarded as a mature branch of chemistry, with many applications for its products, but with few completely new fields. The challenge and the opportunities for oleochemistry today lie in the changing economic and ecological conditions. Availability and price development of oils and fats are discussed with particular reference to European conditions, for these are the prerequisites if oleochemicals are to be competitive and are to improve their chances in the marketplace. The importance and development of the oleochemical raw material fatty acids, fatty acid methyl esters, glycerine, fatty alcohols and amines are considered on the basis of historical data. In considering future developments of oleochemicals, the capacity, demand and the possible influence of petrochemistry or crude oil is discussed. The highly developed oleochemical raw materials industry is a flexible supplier of medium-to long-chain fatty alkyl groups. These facts, together with the well organized supply lines for raw materials and the considerable potential of these renewable raw materials, could provide the necessary conditions for the oleochemical raw materials industry to fulfil its future tasks on a larger scale. This could arise, for example, due to the partial substitution of petrochemical surfactants, if this should become necessary as a result of developments in the price and availability of crude oil, or on grounds of ecological factors.     

Techno-economic analysis of a biodiesel production process from vegetable oils

Biodiesel, which is defined as the monoalkyl esters of long chain fatty acids derived from a renewable lipid feedstock, has received considerable attention worldwide as a medium-term alternative to diesel fuel obtained from petroleum. Biodiesel can be produced by the transesterification of vegetable oils or animal fats using short-chain alcohols in the presence of a suitable catalyst and glycerol is the only byproduct obtained in significant quantities. In this work a techno-economic analysis of a process that produces biodiesel from vegetable oils is presented with the aim to investigate the dependence of the critical profitability indicators on the production capacity.     

Fatty alcohols

“Fatty” or higher alcohols are mostly C₁₁ to C₂₀ monohydric compounds. In probably no other homologous aliphatic series is the current balance between natural and synthetic products so vividly evident. Natural sources, such as plant or animal esters (waxes), can be made to yield straight chain (normal) alcohols with a terminal (primary) hydroxyl, along with varying degrees of unsaturation. In the past, socalled fatty alcohols were prepared commercially by three general processes from fatty acids or methyl esters, occasionally triglycerides. Fatty acids add hydrogen in the carboxyl group to form fatty alcohols when treated with hydrogen under high pressure and suitable metal catalysts. By a similar reaction, fatty alcohols are prepared by the hydrogenation of glycerides or methyl esters. Fatty alcohols are also prepared by the sodium reduction of esters of fatty acids in a lower molecular weight alcohol. The sodium reduction method was ordinarily too expensive; it was displaced early by the other methods; finally most unsaturated alcohols made by this route were largely replaced. Methyl ester reduction continues to provide perhaps 20% of the saturated fatty alcohols, and selective hydrogenation with the use of special catalysts such as copper or cadmium oxides was developed for the production of oleyl alcohol. Synthetic or petroleum technology for long chain alcohols include the Ziegler process, useful for straight chain, even-numbered saturated products. A second is the carbonylation and reduction of olefins affording medium or highly branched chain alcohols. Paraffin oxidation affords mixed primary alcohols. Fatty alcohols undergo the usual reactions of alcohols. They may be reacted with ethylene oxide to yield a series of polymeric polyoxyethylene alcohols or with acetylene under pressure to yield vinyl ethers or with vinyl acetate to give vinyl ethers.     

Aspekte bei der Hydrierung von Fetten und Fettsäuren

Aspects of Hydrogenation of Fats and Fatty Acids Hydrogenation of fat products is of great significance, both for human and animal nutrition as well as for technical purposes. In the area of nutrition, adequate food for the increasing world population is unthinkable without utilization of all fat resources, that can be made available as food fats only after catalytic hydrogenation. In the area of technical use, a similar development is observed owing to shortage of mineral oils. Thus, fatty alcohols derived from vegetable oils and waxes can already compete in price with fully synthetic fatty alcohols derived from mineral oils. In the past 70 years of hydrogenation of fats till the present time, catalysts based on nickel have been most commonly used. In addition, small proportions of catalysts based on copper and noble metals have also been used. Homogenous catalysts have been used very recently. The present communication deals primarily with the hydrogenation of neutral fats and fatty acids using nickel catalysts. The aspects of selectivity and isomerization in the partial hydrogenation of neutral fats are discussed. In the hydrogenation of fatty acids and their derivatives, emphasis is laid on other factors, such as activity, poisoning and acid resistance of the catalyst. These factors are discussed.     

Direct determination of saturated fatty acids in fats,oils, and methyl esters

Summary A direct gravimetric method has been developed for the determination of saturated fatty acids in fats, oils, and methyl esters. The procedure involves methanolysis of the triglycerides to produce methyl esters, followed by oxidation of the unsaturated methyl esters by potassium permanganate. The undesired, acidic oxidation products are removed by alkaline washing and the saturated methyl esters thus isolated are weighed directly. The method is intended for the determination of saturated fatty acids having C₁₆ or longer carbon chains. Small quantities of C₁₄ saturated acids will be included in the determination if present with other higher saturated acids. The method is applicable to both natural and hydrogenated vegetable oils. It is not applicable to oils containing large amounts of C₁₄ and lower saturated acids. Concentrations of saturated acids ranging from 3 to 90% in known glyceride mixtures and from 0.3 to 95% in mixtures of methyl esters were determined with an average difference from the calculated value of 0.8%. Replicate determinations on samples in the 10 to 30% saturates range gave a standard deviation of 0.3 to 0.4%. Presented at the spring meeting, American Oil Chemists’ Society, New Orleans, La., April 28 to May 1, 1957     

Kinetics of hydrolysis and methyl esterification for biodiesel production in two-step supercritical methanol process

For high-quality biodiesel fuel production from oils/fats, the catalyst-free two-step supercritical methanol process has been developed in a previous work, which consists of hydrolysis of triglycerides to fatty acids in subcritical water and subsequent methyl esterification of fatty acids to their methyl esters in supercritical methanol. In this paper, therefore, kinetics in hydrolysis and subsequent methyl esterification was studied to elucidate reaction mechanism. As a result, fatty acid was found to act as acid catalyst, and simple mathematical models were proposed in which regression curves can fit well with experimental results. Fatty acid was, thus, concluded to play an important role in the two-step supercritical methanol process.     

Synthesis of wax esters for use as possible sperm oil replacements

In efforts to prepare wax esters chemically similar to those comprising sperm oil, selected fats or blends thereof were reduced to alcohols which then were reacted with the initial triglycerides to get such wax esters. For instance, lard oil was reduced to lard oil alcohol in the presence of sodium and methyl isobutyl carbinol in xylene. Most of the resulting sodium alcoholates (95–98%) were decomposed with urea, and subsequent addition of lard oil (triglycerides) resulted in rapid formation of the desired wax esters in ca. 80–90% yields. In preliminary studies, the same wax esters were prepared by a more circuitous route. The alcoholates were decomposed completely with urea, the fatty alcohols were liberated, and they then were esterified with free lard oil acids. Similarly treated were a blend of lard, coconut and crambe oils, fractionated tallow, and a commercial grade oleic acid. Presented at the AOCS Meeting, New Orleans, April 1973. ARS, USDA.     

Fatty methyl ester hydrogenation to fatty alcohol part I: Correlation between catalyst properties and activity/selectivity

Fatty alcohols, derived from natural sources, are commercially produced by hydrogenation of fatty acids or methyl esters in slurry-phase or fixed-bed reactors. One slurry-phase hydrogenation of methyl ester process flows methyl esters and powdered copper chromite catalyst into tubular reactors under high hydrogen pressure and elevated temperature. In the present investigation, slurry-phase hydrogenations of C₁₂ methyl ester were carried out in semi-batch reactions at nonoptimal conditions (i.e., low hydrogen pressure and elevated temperature). These conditions were used to accentuate the host of side reactions that occur during the hydrogenation. Some 14 side reaction routes are outlined. As an extension of this study, copper chromite catalyst was produced under a number of varying calcination temperatures. Differences in catalytic activity and selectivity were determined by closely following side reaction products. Both activity and selectivity correlate well with the crystallinity of the copper chromite surface; they increase with decreasing crystallinity. The ability to follow the wide variety of side reactions may well provide an additional tool for the optimized design of hydrogenation catalysts.     

Catalytic chemistry of preparation of hydrocarbon fuels from vegetable oils and fats

The problem of preparing engine fuels from renewable feedstocks via the catalytic processing of inedible vegetable oils and fats is considered. Different types of inedible feedstocks are described, including algae, inedible plants, wood processing products, and waste fats and oils. Catalytic processes are considered for preparing the second generation biodiesel through the hydrodeoxygenation and deoxygenation of triglycerides and fatty acids, and of their derivatives. Brief information on catalysts for the deoxygenation of fatty acids is given. Special attention is given to analyzing the mechanism and kinetics of the deoxygenation reaction. Based on conducted kinetic and quantum-chemical investigations and using the literature data, a deoxygenation mechanism is proposed by the authors that explains the observed dependences of decarboxylation and decarbonylation contributions on the reaction conditions (the stearic acid, water, and catalyst concentrations, the hydrogen and CO pressures, and the temperature). Examples of the application of hydrocarbon biodiesel in transport are presented.     

Hydrotreating Model Comparison of Raw Castor Oil and its Methyl Esters for Biofuel Production

Some of the main problems during vegetable oil hydrotreating are the high heat of reaction released, the huge quantity of expensive hydrogen required, and the high corrosion rates in the equipment. Some insights into the advantages and disadvantages of processing raw vegetable oils or their respective fatty acid methyl esters are given. The ASPEN Plus process simulator was used for the simulation of a hydrotreating process, with two different feedstocks coming from the same plant: raw castor oil and castor oil methyl esters. That process was modeled with two stoichiometric reactors in series. The technical viability of using methyl esters as hydrotreating feedstock for the production of biofuels such as green gasoline and diesel is demonstrated.     

Fatty acid compositions of indian shark liver fats

Summary Liver fats ofCarcharias limbatus andPristis cuspidatus from the West Coast of India have been studied. Lithium salt-acetone and lead salt-alcohol methods were adopted for the resolution of the fatty acids. An efficient, electrically heated and packed column has been employed for fractionation of the methyl esters of fatty acids. These fats have been found to have a high content of saturated fatty acids and thus belong to the fourth group of Tsujimoto's classification of Elasmobranch fish liver fats. Analyses of the liver oils from the same species of fish show that there is a tendeney towards saturation or hydrogenation of polyethylenic acids accompanied by an increasing concentration of unsaponifiable matter, which is mainly alcohol ethers of the selachyl type, in accordance with Lovern's views.     

Acyl esters from oxo-derived hydroxymethylstearates as plasticizers for polyvinyl chloride

Hydroxymethylstearates were made by hydroformylation or oxo reaction of mono- and polyunsaturated fats and esters with either rhodium-triphenylphosphine or cobalt carbonyl catalysts. Rhodium-oxo products were hydrogenated with nickel catalyst, whereas, cobalt-oxo products were heated directly under hydrogen pressure. Hydroxymethyl fatty alcohols also were prepared by a two-step copper-chromite hydrogenation of hydroformylated linseed fatty esters. Of these hydroxymethyl compounds, 39 were converted to their acetates and other acyloxy derivatives and then evaluated as primary plasticizers for polyvinylchloride. For compounds with good compatibility, methyl 9(10)-acetoxymethylstearate and 9(10)-acetoxymethyloctadecyl acetate gave the lowest flex temperature (−47 C). An unusual combination of good compatibility and low flex temperature was obtained with 2-methoxyethyl 9(10)-acetoxymethylstearate. Addition of more than one acetoxymethyl group in the fatty acid molecule, made possible by rhodium hydroformylation, imparted good compatibility and outstanding permanence (low migration and volatility) but raised flex temperature. Butyl diacetoxymethylstearate, methyl triacetoxymethylstearate, and polyacetoxymethyloctadecyl acetate from linseed esters displayed good compatibility, strength, and volatility characteristics. As glycerides, acetoxymethylated safflower and linseed oils produced good compatibility and outstanding permanence, better than esters commonly used as commercial plasticizers.     

Selective hydrogenation of fatty acids and methyl esters of fatty acids to obtain fatty alcohols–a review

In this paper, a review is presented of the evolution of different catalytic systems and operating conditions used in the selective hydrogenation of acids and esters of fatty acids to obtain fatty alcohols, which have broad industrial applications in the oleochemical industry. In addition, the current status of the different technologies used industrially (Lurgi, Davy and Henkel) for obtaining fatty alcohols, as well as major global sources of raw materials for the oleochemical industry are put forward. Finally, the reaction mechanisms of the selective hydrogenation process of oleic acid and methyl oleate to obtain the corresponding unsaturated alcohol as well as the new catalysts proposed by researchers are described. © 2016 Society of Chemical Industry     

Lipase-catalyzed production of biodiesel

Lipases were screened for their ability to transesterify triglycerides with short-chain alcohols to alkyl esters. The lipase fromMucor miehei was most efficient for converting triglycerides to their alkyl esters with primary alcohols, whereas the lipase fromCandida antarctica was most efficient for transesterifying triglycerides with secondary alcohols to give branched alkyl esters. Conditions were established for converting tallow to short-chain alkyl esters at more than 90% conversion. These same conditions also proved effective for transesterfying vegetable oils and high fatty acid-containing feedstocks to their respective alkyl ester derivatives. Presented in part at the 86th Annual Meeting of American Oil Chemists’ Society, San Antonio, Texas, May 1995.     

Effects of ionizing radiation on some vegetable fats

The volatile compounds produced by irradiation, under vacuum at 6 megarads, in five vegetable fats were analyzed qualitatively and quantitatively by gas chromatography and mass spectrometry. A series of compounds,n-alkanes, 1-alkenes, internally unsaturated alkenes, alkadienes, alkatrienes, alkanals and methyl and ethyl esters of fatty acids, were identified in each of the fats studied. A wide variation occurs in the amounts of the volatiles produced from each fat. The major radiolytic products were few in number and were found to depend largely on the fatty acid composition of the fat. These compounds were essentially the hydrocarbons containing one or two carbon atoms less than the component fatty acids. This relationship was found consistent if radiolytic products of fats with different fatty acid compositions are compared or if the fatty acid composition of the same fat is altered by hydrogenation. The results correlate well with those of earlier studies on simple triglycerides.