Fatty acids, dimerized

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). 

Molecular distillation occurs where the vapor path is unobstmcted and the condenser is separated from the evaporator by a distance less than the mean-free path of the evaporating molecules (86). This specialized branch of distillation is carried out at extremely low pressures ranging from 13—130 mPa (0.1—1.0 p.m Hg) (see Vacuum technology). Molecular distillation is confined to appHcations where it is necessary to minimize component degradation by distilling at the lowest possible temperatures. Commercial usage includes the distillation of vitamins (qv) and fatty acid dimers (see Dimeracids). 

Polyamides provide RT cure of epoxy-terrninated resins as weU as flexibiHzation they are derived by reaction of dimerized vegetable oil fatty acids (dimer acids) with polyamines. 

M Maniar, AJ Domb, A Haffer, J Shah. Controlled-release of a local anesthetic from fatty-acid dimer based polyanhydride. J Controlled Release 30 233-239, 1994. 

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). 

Chang (64) used a porous styrene/divinylbenzene gel to determine small amounts of fatty acid dimers in tall oil. Hase and Harva (66) separated the monomeracid methyl esters from dimers and higher oligomers using a modified dextran gel SEPHADEX LH-20. 

Pharmaceutical research has to date been focused on polyanhydrides derived from sebacic acid (SA) and its copolymers with bis(p-carboxyphenoxy)propane (CPP) [75,113,115,119]. More recently, a new class of polyanhydrides was presented, containing fatty acid dimers (FAD) [ 116,118,258]. Erosion characteristics, microsphere preparation, pH-dependence, release rates, morphology, and in vivo performance of polyanhydrides from SA, CPP, and FAD have been intensely studied [75, 111-115,117, 119, 258-260]. Other unsaturated polyanhydrides have been derived from ricinoleic acid [261] and ricinoleic acid half-es-... 

Fatty acid dimers, (II), trimers, and tetramers effective as PLA2 inhibitors having antioxidant and anti-inflammatory properties were prepared by Franson (2) and used in treating nerve and tissue damage in central and peripheral neurological inflammatory conditions. 

Fatty acids have been used previously in the development of polymers for biomedical applications as they are considered to be inert, inexpensive and biocompatible. The main fatty acids which are used as a base for synthesis of biomedical polymers (polyanhydrides) are stearic acid (/), erucic acid (C22 unsaturated fatty acid) dimer (2), bile acid dimer (i), ricinoleic acid 4) and other fatty acids (5), middle long carbon chain (C12 - 15) dibasic acids, such as dodecanedioic, brassylic acid, tetradecandioic acid and pentadecandioic acid (/). 

Oil Type Trans-Fatty Acids %) Dimeric Triacyigiycerois (%)... 

Poly(erucic acid dimer) or poly(FAD), (FAD, fatty acid dimer)... 

Spin-trapping techniques have been used to study reactions of lipoxygenase with linoleic acid ( ). It was proposed that the formation of dimeric linoleic acid required the involvement of hydroperoxylinoleic acid ( ). The ESR spectrum from the interactions of the PUFA radical and the spin-trap indicated this involvement occurred Similar spin-trapping techniques could be used to investigate the possibility that DPE s may ultimately induce formation of various fatty acid dimers (e.g., dimers of linolenic acid). Formation of such polymers should dramatically affect membrane function. 

C18-Unsaturated fatty acids, dimers. See Dimer acid Cupric dinitrate. See Copper nitrate (ic)... 

Synonyms Cl 8-Unsaturated fatty acids, dimers Fatty acids, C18-unsat-urated, dimers ClassiTication Dibasic acid... 

Poly(fatty acid dimer-co-sebacic acid), x= 7... 

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