Oleic acid, dimer

Dimerization of unsaturated fatty acids, to. so-called dimer acids, is widely practised in industry, where acid-treated clays are invariably used as a catalyst. In the case of oleic acid the major products are dimers, trimers, and isosteric acid. Koster et al. (1998) have investigated the relative importance of the various acid sites as well as structural and textural parameters of montmorrilonite. The interlamellar space dominates the oleic acid dimerization and the active site is the tetrahedrol substitution site. 

US 5879701 Oleic acid dimer neodecanoic acid Cygnus... 

The dimer acids [61788-89-4] 9- and 10-carboxystearic acids, and C-21 dicarboxylic acids are products resulting from three different reactions of C-18 unsaturated fatty acids. These reactions are, respectively, self-condensation, reaction with carbon monoxide followed by oxidation of the resulting 9- or 10-formylstearic acid (or, alternatively, by hydrocarboxylation of the unsaturated fatty acid), and Diels-Alder reaction with acryUc acid. The starting materials for these reactions have been almost exclusively tall oil fatty acids or, to a lesser degree, oleic acid, although other unsaturated fatty acid feedstocks can be used (see Carboxylic acids. Fatty acids from tall oil Tall oil). 

Most of the products Hsted in Tables 1—3 are based on manufacture from tall oil fatty acids. Dimer acids based on other feedstocks (eg, oleic acid) may have different properties. A European manufacturer recently announced availabiUty of a 44-carbon dimer acid, presumably made from an emcic acid feedstock (7). 

Structure and Mechanism of Formation. Thermal dimerization of unsaturated fatty acids has been explaiaed both by a Diels-Alder mechanism and by a free-radical route involving hydrogen transfer. The Diels-Alder reaction appears to apply to starting materials high ia linoleic acid content satisfactorily, but oleic acid oligomerization seems better rationalized by a free-radical reaction (8—10). 

A similar reaction occurs with fatty acids (such as stearic acid) or methyl stearate, which undergo isomerization, cracking, dimerization, and oligomerization reactions. This has been used to convert solid stearic acid into the more valuable liquid isostearic acid [102] (Scheme 5.1-70). The isomerization and dimerization of oleic acid and methyl oleate have also been found to occur in chloroaluminate(III) ionic liquids [103]. 

Other alkenoic acids that have been dimerized with retention of configuration at the double bond are oleic acid (23 % dimer yield), elaidic acid (44%) [143], and erucic acid (40%) [144]. 

Cowan Teeter (1944) reported a new class of resinous substances based on the zinc salts of dimerized unsaturated fatty acids such as linoleic and oleic acid. The latter is referred to as dimer acid. Later, Pellico (1974) described a dental composition based on the reaction between zinc oxide and either dimer or trimer acid. In an attempt to formulate calcium hydroxide cements which would be hydrolytically stable, Wilson et al. (1981) examined cement formation between calciimi hydroxide and dimer acid. They found it necessary to incorporate an accelerator, alimiiniiun acetate hydrate, Al2(OH)2(CHgCOO)4.3H2O, into the cement powder. 

Fatty acids have also been converted to difunctional monomers for polyanhydride synthesis by dimerizing the unsaturated erucic or oleic acid to form branched monomers. These monomers are collectively referred to as fatty acid dimers and the polymers are referred to as poly(fatty acid dimer) (PFAD). PFAD (erucic acid dimer) was synthesized by Domb and Maniar (1993) via melt polycondensation and was a liquid at room temperature. Desiring to increase the hydrophobicity of aliphatic polyanhydrides such as PSA without adding aromaticity to the monomers (and thereby increasing the melting point), Teomim and Domb (1999) and Krasko et al. (2002) have synthesized fatty acid terminated PSA. Octanoic, lauric, myristic, stearic, ricinoleic, oleic, linoleic, and lithocholic acid acetate anhydrides were added to the melt polycondensation reactions to obtain the desired terminations. As desired, a dramatic reduction in the erosion rate was obtained (Krasko et al., 2002 Teomim and Domb, 1999). 

Xu et al. (2001) synthesized the copolymers of a dimer fatty acid (dimer of oleic and linoleic acids) and sebacic acid (P(DA-SA)) by melt polycondensation of acetylated prepolymers. Degradation and drug release kinetics showed that increasing dimer acid content decreased the release rate (Xu et al., 2001). 

Polyanhydrides prepared from fatty acids are good candidates for the delivery of hydrophilic drugs due to the desired hydrophobicity of the natural fatty acids in the main chain of the polyanhydrides 11). These polyanhydrides have two series of acid monomers one has longer carbon chain, such as dimer erucic or oleic acid another has shorter carbon chain, such as sebacic acid (2). Fatty acids can be incorporated into the polymer chain by one of two ways by... 

The synthesis of dimeric fatty acids is based on the reaction between a fatty acid with one double bond (oleic acid) and a fatty acid with two double bonds (linoleic acid) or three double bonds (linolenic acid), at higher temperatures in the presence of solid acidic catalysts (for example montmorillonite acidic treated clays). Dimerised fatty acids (C36) and trimerised fatty acids (C54) are formed. The dimer acid is separated from the trimeric acid by high vacuum distillation. By using fatty dimeric acids and dimeric alcohols in the synthesis of polyesters and of polyester polyurethanes, products are obtained with an exceptional resistance to hydrolysis, noncrystalline polymers with a very flexible structure and an excellent resistance to heat and oxygen (Chapter 12.5). Utilisation of hydrophobic dicarboxylic acids, such as sebacic acid and azelaic acid in polyesterification reactions leads to hydrolysis resistant polyurethanes. 

Thus, the dimerisation of unsaturated fatty acids takes place at higher temperatures in the presence of catalysts (for example acidic clays, montmorillonite type). One molecule of oleic acid (having one double bond) reacts with one mol of linoleic acid (having two double bonds) and this forms a dimeric acid with a cycloaliphatic structure. 

Weakly acidic fatty acids such as oleic acid undergo dissociation to form ions (R ) at high pH values and neutral molecules (RH) at low pH values. In the intermediate pH region, the ions and neutral molecules can associate to form iono-molecular complexes (Kulkarni and Somasundaran, 1980). As the collector concentration is increased, miceUization or precipitation of the collector will occur. In addition, collector species can undergo associative interactions to form other aggregates such as dimers (R ) (Somasundaran and Anantha-padmanabhan, 1979b). Since the surface activities of these species will vary from those of each other, flotation of minerals with these collectors can also be expected to be dependent upon pH and such solution conditions. 

Correlation of oleate adsorption and flotation maximum at about pH 7.5 for a variety of minerals and high abstraction (adsorption + surface precipitation) below this pH with the species distribution diagram (Fig. 4.9) suggests that the role of acid-soap dimer and precipitated oleic acid can be significant in controlling the adsorption and resultant flotation behavior. 

Polyanhydrides were synthesized from dimer and trimer of unsaturated fatty acids. The dimers of oleic acid and erucic acid, prepared by radical coupling via... 

The degradation rates for a number of polyanhydrides are available in the literature [1, 82,83], However, recently, a new class of polyanhydrides poly(FAD-SA) have been synthesized from non-linear hydrophobic dimer of oleic acid or erucic acid and relatively hydrophilic sebacic acid. This copolymer can be prepared in various ratios of the monomers to achieve the desired degree of hydrophobicity increasing the percentage of FAD, a more hydrophobic copolymer, is obtained. Another advantage of this copolymer is its ability to be formulated as films, microspheres, and beads [84],... 

The fatty acid spectrum of rice bran oil is 22-25% palmitic acid, 37-41% oleic acid and 37-41% linoleic acid. More recently, interest in rice oil escalated with its identification as a healthy oil that reduces serum cholesterol. Rice bran is a good source of antioxidants including vitamin E and oryzanol (ferulic esters of sterols and triterpene alcohols), cholesterol-lowering waxes and antitumor compounds like rice bran saccharide.Besides applications in nutrition and in phyto-chemicals, rice bran oil has traditionally been used for industrial applications, such as dimer acid manufacturing, depending on pricing for alternative vegetable oils. 

Yarush et ai. 159) used liposomes prepared from phosphatidylcholine, cholesterol hemisuccinate. and oleic acid to the skin with a DNA repair enzyme. T4 endonuclease V. Before and after exposure to UV-B light the enzyme was applied on the skin. After 6 h the animals were sacrificed and the DNA dimers counted. It appeared that post- and pretreatment with DNA repair-loaded liposomes resulted in a decrease in the number of dimers. Repealed application did not funher enhance the repair. These results. suggest that the DNA repair at least entered the cells. In a. second study. Yarosh et al. (60) studied the fate of the di-i-labellcd... 

Definition Mixture of mono and diesters of oleic acid and a dimer of glycerin Properties HLB 3.5 nonionic Uses Emulsifier in cosmetics, foods, and pharmaceuticals Reguiatory FDA 21CFR 172.854 Manuf./Distrib. A E Connock http //www. connock. co. uk Trade Name Synonyms Hostacerin DGO [Clariant/Functional Chems.]... 

Decyl ketene dimer Tetradecyl ketene dimer Octadecyl ketene dimer Docosyl ketene dimer Phenyl ketene dimer Cyclohexyl ketene dimer Naphthenic acid ketene dimer 10-Dodecylenic acid ketene dimer Oleic acid ketene dimer Petroselinic acid ketene dimer Linoleic acid ketene dimer Eleostearic acid ketene dimer Parinaric acid ketene dimer Gadoleic acid ketene dimer Cetoleic acid ketene dimer Selacholeic acid ketene dimer Babassu oil ketene dimer Palm oil ketene dimer Peanut oil ketene dimer Beef tallow ketene dimer... 

Many other oxidizing agents will convert oleic acid to give azelaic acid but none is used industrially. The Cg dibasic acid can also be made by dimerization of butadiene, carbonylation of the cyclo-octadiene, and caustic fusion of the C9 product. 

The dibasic acids, dimer acids, are produced commercially from vegetable oil fatty acids or esters, mainly C18 unsaturated fatty acids or esters, such as linoleic acid, ricinoleic acid, oleic acid. These fatty acids or esters derived from vegetable oils, such as dehydrated castor oil, tall oil, tung oil etc., are polymerized to give a mixture of dibasic and polybasic acids. This polymerized monomer chiefly includes dibasic dimeric fatty acids and small fractions of the monomeric, trimeric and higher polymeric fatty acids and, therefore, these are designated by the term dimer acids . These dimer acids find an outlet as important intermediates for the manufacture of plasticizers, synthetic lubricants, and high polymeric products because of their increased functionality compared with ordinary fatty acids. 

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