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.     

Synthese neuer verzweigter Fettsäureester durch homogene Rhodiumkatalyse

Synthesis of New Branched Fatty Acids by Rhodium Catalyzed Homogeneous Oligomerisation Branched fatty acids possess, compared to their linear homologues, unusual physical properties. They are used for many applications, for example in lubricants, cosmetics, as softener, defoamer and wood protecting agents. We describe a new homogeneous catalyzed method which allows to synthesize defined internal branched fatty acids in yields up to 95%. The reactions is carried out by a rhodium catalyzed additon of olefins to linoleic acid or conjugated C18: 2 fatty acids.     

Gezielte Synthese von Dimerfettsäuren

Selective Synthesis of Dimer Fatty Acids Dimer fatty acids are aliphatic C₃₆-dicarboxylic acids, and are important raw materials for the manufacture of polyamides, polyesters, heavy duty lubrication oils and plasticizers. They are made by condensation of two unsaturated fatty acids in the presence of a catalyst. Because of the complicated reaction mechanism a complex mixture is obtained. Therefore only insufficient information in regard to the structure has been obtained. We report the synthesis of single isomers of linear and branched C₃₆-dicarboxylic acids. Characteristic spectroscopic and GC-data of the structural types are reported.     

Eigenschaften verzweigter Fettsäuren

Properties of Branched Fatty Acids Physical and chemical properties of branched fatty acids and hydroxy fatty acids were determined and compared with those of n-fatty acids.     

Isolierung und Strukturaufklärung polyverzweigter Fettsäuren aus Fischöl

Isolation and Structure Determination of the Polybranched Fatty Acids from Fish Oil From a sample of sea fish oil, three saturated polymethyl branched fatty acids could be separated in pure state as methyl esters by using urea adduct, column chromatography and distillation methods. These could be identified as 4,8,12-trimethyl-tridecanoic acid, 2,6,10,14-tetramethyl-pentadecanoic acid and 3,7,11,15-tetramethyl-hexadecanoic acid, with the help of molecular weight determination, ultimate analysis, IR-, NMR- and mass-spectroscopy. The structures could be proved by synthesis. Many other branched chain fatty acids were synthesised for comparison. The synthesis and the infrared spectrums of these compounds are given in details.     

Die massenspektrometrische Fragmentierung von Neopentylpolyolestern III Neopentylglycoldifettsäureester

Mass Spectrometric Fragmentation of Neopentylpolyolesters, Part III: Fatty Acid Diesters of Neopentylglycole The fragmentation of the homologous fatty acid diesters of neopentylglycole (C₂ to C₁₈) upon electron impact was investigated. Main fragments arise by M-RCOO and M-RCOOH. Cyclic acetal structures for these ions are postulated. Subsequent fragmentation was elucidated by DADI-measurements and high resolution measurements. The influence of the length of the fatty acid chain upon the fragmentation is discussed. Esters of branched fatty acids can be distinguished from esters of n-fatty acids by characteristic ions.     

Die massenspektrometrische Fragmentierung von Neopentylpolyolestern II Trimethylolpropantrifettsäureester

Mass Spectrometric Fragmentation of Neopentylpolyolesters, Part II: Fatty Acid Triesters of Trimethylolpropane The fragmentation of the homologous fatty acid triesters of trimethylolpropane (C₂ to C₁₄) upon electron impact was investigated. Main fragments arise by M–RCOO and M–RCOOH. Cyclic acetal structures for these ions are postulated. Subsequent fragmentation was elucidated by DADI-measurements and high resolution measurements. The influence of the length of the fatty acid chain upon the fragmentation is discussed. Esters of branched fatty acids can be distinguished from esters of n-fatty acids by characteristic ions.     

Produkte der Dimerisierung ungesättigter Fettsäuren VIII: Über die Zusammensetzung der Fraktion der “Intermediates” bei der Fettsäuredimerisierung

Products of Dimerisation Unsaturated Fatty Acids VIII: The Fraction of “Intermediates” Obtained by Dimerisation of Unsaturated Fatty Acids The fraction of “intermediates” which is obtained by dimerisation of unsaturated fatty acid contains straight chain saturated fatty acids with 20-24 carbon atoms as well as methyl branched isomers thereof. The production of these compounds is probably caused by the presence of small amounts of monounsaturated fatty acids with 20-24 carbon atoms in the starting material. The fraction of “intermediates” contains in addition monocarboxylic acids with 36 carbon atoms. These are probably formed after dimerisation by an intramolecular cyclisation reaction under participation of one carboxylic group, followed by hydrogenation of the produced carbonyl group. Finally the formed alcoholic group is eliminated as a water molecule, and the produced double bond is hydrogenated.     

Produkte der Dimerisierung ungesättigter Fettsäuren XII: Die Dimerisierung von Konjuensäure

Products of Dimerisation of Unsaturated Fatty Acids XII: The Dimerisation of Conjugated Fatty Acids Dimeric fatty acids obtained by the clay-catalyzed dimerisation of the conjugated fatty acid (mixture of 9,11-octadecadienoic acid and 10,12-octadecadienoic acid) can be separated via HPLC in form of their dimethylates in three fractions in accordance with results obtained by separation of dimeric fatty acids of linoleic acid. The first fraction of aromatic dimeric fatty acids with the molecular weight 586 mainly contains compounds with a tetrasubstituted ring system. The second fraction, consisting of alicyclic unsaturated dimeric fatty acids, is characterized by the molecular weight 590 and a cyclohexene ring system. The third fraction corresponds to alicyclic saturated dimeric fatty acids. Dimeric fatty acids resulting of a Diels-Alder-reaction were detected neither in the end products nor as products in the early phase of the dimerisation. The results obtained by the investigation of the dimerisation of conjugated fatty acids are similar to those of the dimerisation of linoleic acid. Consequently a Diels-Alder-reaction is not involved in the formation of dimeric fatty acids. Although conjugated fatty acids are predominated to undergo a Diels-Alder-reaction no such products could be detected. This result strengthens the thesis that the dimerisation of unsaturated fatty acids is initiated by a cationic mechanism. The composition of the dimeric fatty acid using conjugated fatty acids is more uniform than that of usual mixtures of linoleic and linolenic acid. This provides evidence that a modification of the educt fatty acids can yield new structures of the dimerisation products.     

Hydrolysestabile fettchemische Polyole für Polyurethananwendungen

Saponification Resistant Polyols for Polyurethane Applications Based on Oleochemical Raw Materials Fatty alcohol hydrogenation technology is used for manufacturing of interesting polyfunctional alcohols from unsaturated fatty raw materials. Two synthetic approaches are discussed: the preparation of C₂₀-alcohols with two primary and one secondary OH-group by hydrogenation of ring-opening products of epoxidized methylesters and the preparation of C₃₆-dimer fatty alcohols with two primary OH-groups, which are derived from dimer fatty acids. Requirements for special applications like high difunctionality can be achieved by using the appropriate dimer acid as starting material. These hydrophobic polyols contain no ester groups and are therefore useful for preparation of polyurethanes resistant to saponification.     

Herstellung verzweigter Fettsäuren durch katalytische Oxidation von Alkoholen

Synthesis of Branched Fatty Acids by Catalytic Oxidation of Alcohols Transition metals fixed on solid supports are able to catalyze the oxidation of branched alcohols with air yielding branched fatty acids. As typical example 2-hexyldecanol was chosen which is well available via the guerbet reaction. Catalyst screening and reaction optimization will be described. Highest activities were obtained with palladium-, platinum- and ruthenium-catalysts. 2-hexyldecanoic acid (“isopalmitic acid”) was synthesized in yields of 65%; important by-products are wax esters and 7-pentadecanone.     

Back to the future: Fatty acids,the green genie to design smart soft materials

Fatty acids are widely used in industries for various applications as soaps or in their crystalline form. Fatty acid soaps are used as surface-active agent to stabilize foams and emulsions, for detergency, and surface wetting. Fatty acid molecules in organic solvents are used as low-molecular-mass organic gelators. Currently, there is a renewed interest in using fatty acids in industrial applications instead of petrochemical surfactants since fatty acid soaps are green surfactants. Fatty acids exhibit also many advantages, including the design of responsive soft-materials. Fatty acid soaps are natural pH and thermoresponsive surfactants, which can lead to responsive foams and emulsions. In their crystalline form, fatty acid crystals in both aqueous and non-aqueous solvents stabilize liquid foams. These crystals are also efficient in the production of liquid marbles. Fatty acids are solvosurfactants with the ability to form microemulsions and capillary suspensions. In this review, we illustrate how fatty acid molecules can be used in the manufacture of multiresponsive soft-materials ranging from aqueous and non-aqueous foams, emulsions, nanoemulsions, microemulsions, liquid marbles and capillary suspensions.     

Branched polyols based on oleic acid for production of polyurethane foams reinforced with bamboo fiber

Fatty acids and bamboo fiber (BF) are abundant and renewable materials that have great potential application in the production of high-valued chemical products. In this work, polyurethane foams (PUFs) with remarkable mechanical and thermal properties were synthesized using OAPs (polyols-based on oleic acid (OA), an important fatty acid) and polymeric isocyanates. PUFs were reinforced with BF. Novel OAPs were prepared from OA through a process consisting of hydroxylation, carboxylation, and esterification. The strategy afforded branched polyols with high content of primary hydroxyls. Phthalic anhydride was used as a modifying agent to improve the properties of OAPs. Physicochemical properties of the polyols were characterized by standard methods (analyses of hydroxyl number, viscosity, acid value, density, and water content) and instrumental analysis (gel permeation chromatography, Fourier transform infrared spectroscopy, and thermogravimetry). The mechanical properties of polyurethane foams made from the OAPs were improved by applying modified BF as filler. With BF having particle sizes of 250–500 μm, the compressive strength of composite foams increased from 0.45 to 0.66 MPa, and the flexural strength increased from 0.66 to 0.77 MPa. Surface modification of BF by alkali could enhance the interfacial interaction between the reinforcing fibers and foam matrix, resulting in greater mechanical strength of the PUFs. It also improved the thermal stability and dynamic thermomechanical properties of PUFs.     

Fettsäurenaufnahme des Menschen und Möglichkeiten der Beeinflussung durch die Tierernährung

Fatty acid intake of men and possibilities to influence the intake by animal nutrition. About 70% of total fat intake (≈ 100 g per person per day) are from fat of animal origin in Germany. Animal nutrition may influence fat content and fatty acid pattern in animal products. This paper summarizes the influence of feeding on fatty acid pattern of meat (pork, beef, poultry, rabbit, fish), milk and eggs. Fatty acid intake is demonstrated under consideration of fat intake of men and variation of fatty acid pattern of various fats of animal origin. Daily fat intake of men amounted to 43 g saturated, 37 g monoen and 13 g polyen fatty acids. It may vary between 38 and 46 g saturated, 33 and 45 g monoen and 11 and 17 g polyen fatty acids if variation of fatty acid pattern of animal fats is considered. By combination of lower fat intake and changed fatty acid pattern of animal products fatty acid intake may be changed to more monoen and polyen fatty acids.     

Improved Extraction of Saturated Fatty Acids but not Omega-3 Fatty Acids from Sheep Red Blood Cells Using a One-Step Extraction Procedure

Several methods are available to extract total lipid and methylate fatty acids from a range of samples including red blood cells (RBC). Fatty acid analysis of human RBC can be undertaken using a two-step extraction and methylation or a combined one-step extraction and methylation procedure. The lipid composition of sheep RBC differs significantly from that of humans and may affect their extraction. The purpose of the current study was to examine the efficiency of extraction of lipid and detection of fatty acids from sheep RBC using a one-step procedure. Fatty acids were analysed using a one-step extraction and methylation procedure using methanol:toluene and acetyl chloride in comparison with a two-step procedure involving extraction of lipid using chloroform:methanol and separate methylation. Concentrations of saturated fatty acids including C16:0 and C18:0 were significantly higher (42.6 and 33.9 % respectively) following extraction using the one-step procedure compared with the two-step procedure. However, concentrations of some polyunsaturated fatty acids, including C20:5n-3 and C22:6n-3 were not significantly different between either procedure. The improved detection of fatty acids may be related to the ability of different solvents to extract different lipid fractions. The differential extraction of lipids and detection of fatty acids from sheep RBC may have important implications in studies examining the effect of dietary treatment on the possible health benefits of fatty acids.     

Verwendung eines neuen Typs verzweigtkettiger Fettsäuren zur Modifizierung von Alkydharzen

Use of a New Type of Branched Chain Fatty Acids for the Modification of Alkyd Resins It was established that the modification of drying alkyd resins with branched chain fatty acids invariably leads to change in properties of the paint films. By this modification the drying time is reduced, and the film hardness as well as the limit of wrinkling increased. Simultaneously, the other technological properties are not affected so that the rate of drying and the hardness of the film can be increased without altering the elasticity. Based on the above results, fatty acids suitable for modification are suggested.     

Skin lipids. III. Fatty chains in skin lipids. The use ofvernix caseosa to differentiate between endogenous and exogenous components in human skin surface lipid

The literature on the types of fatty chains that occur in skin lipids is reviewed and new data are presented. To ascertain whether certain unusual fatty acids found in human skin surface lipids are truly products of the human skin or are due to some type of external contamination (possibly bacterial), the fatty acids ofvernix caseosa, (the lipoidal material covering the human fetus) were analyzed and compared to those found in human skin surface lipid. The same unusual fatty acids were found invernix caseosa. This indicates that these acids are products of human skin. These acids consist of five classes of saturated branched chain acids and of three classes of monoenes: straight chain,iso andanteiso. All the monoenes are Δ⁶ or derivable from this position by addition of an integral number of 2 carbon units to the carboxyl group. On the polar phase diethylene glycol succinate polyester, the saturated branched chain methyl esters have fractional carbon numbers (by gas chromatography) of 0.15, 0.23, 0.45, 0.63 and 0.75. The series at 0.63 and 0.75 areiso andanteiso, respectively. The series at 0.15 and 0.23 appear to be two newly identified classes of branched chain fatty acids.     

Über die Autoxydation gesättigter Fettsäuren VI: Isolierung und Identifizierung von Oxydationsprodukten der Laurin-, Myristin-und Stearinsäure sowie ihrer Methylester

Autoxydation of Saturated Fatty Acids VI: Isolation and Identification of Cleavage Products Formed by the Oxidation of Laurie, Myristic and Stearic Acids and their Methyl Esters Besides primary reaction products, as reported earlier, also some other substances, considered to be secondary products were identified in the oxidation product of saturated fatty acids and their methyl esters. A large number of methyl ketones, aldehydes and carboxylic acids could be detected by these investigations.     

Die Beeinflussung der Reaktion bei der Oxäthylierung von Fettsäuremonoäthanolamiden

Influencing the Oxyethylation Reaction of Fatty Acid Mono-Ethanolamides In the reaction of fatty acids or methyl esters of fatty acids with mono-ethanolamine, fatty acid-aminoethyl esters and di-fatty acid-ethanolamide esters are formed in addition to mono-ethanolamides of fatty acids. The equilibrium is predominantly towards the mono-ethanolamide of fatty acid. This equilibrium reaction interferes considerably during the oxyethylation of ethanolamides of fatty acids, since at the temperature of oxyethylation the aforestated compounds and their oxyethylation products are formed. Furthermore, amino-oxyethylate and heterocyclic products are always formed which lead to dark and odorous reaction products. Investigations were carried out in order to determine the influence of reaction temperature, catalyst concentration, and nature of starting material on the composition of oxyethylates that are formed by oxyethylation of fatty acid ethanolamides.     

Characterization of products from clay catalyzed polymerization of tall oil fatty acids

Products obtained by acid clay catalyzed dimerization of oleic, elaidic, and tall oil fatty acids were characterized. The monomeric products (35% of total) consisted of stearic, octadecenoic (66%trans-), and mid chain monomethyl branched acids, both saturated and unsaturated. The polymeric products (65% of total) consisted of linear, alicyclic, aromatic, and polycyclic dimers. The tall oil fatty acid based dimer closely resembled oleic dimer in polycyclic character and linoleic dimer in aromatic and linear structures. Oleic dimers contained the highest linear structural content, while linoleic dimer contained the largest polycyclic content. Alicyclic structures were the principal components of all three products. The monocyclic dimer structures present consisted of six membered ring systems with linoleic and tall oil fatty acid dimers containing the highest aromatic contents. Presented at the National American Chemical Society Meeting, New York, August 1972.