Dibasic fatty acids

Fir.. 7. Structure of dibasic fatty acid COOH 04H6 COOH. Long hydrogen bonded chains are formed in the c direction in the crystal... 

As has been mentioned in 1, smooth surfaces of copper, including those deposited electrolytically, reduced copper mirrors, and polished surfaces were quite inactive (a, i) a minute trace of activity only was occasionally detected in commercial copper gauze, but copper prepared by thermal decomposition of either cupric or cuprous oxides, or copper salts of mono- and dibasic fatty acids, by condensation on china-clay rods2 from the vapour (in nitrogen, to prevent oxidation), or by stirring up the atoms of copper into open formation by heating in ammonia at 820°, was active (t). 

Dimer acids, or dibasic fatty acids, are formed either by thermal polymerization or carbon-to-carbon linking of fatty acid chains. Thermal polymerization of monomeric fatty acids like dehydrated castor oil or linoleic acids carried out at 205°C-300°C in an inert atmosphere yields dimer acid. Whereas the latter is established through a Diels-Alder mechanism, involving addition of one molecule of non-conjugated linoleic acid and one molecule of thermally conjugated linoleic acid or dehydrated castor oil [10]. A review of dimerization provides a comprehensive idea about the manufacture of dimer acids [11]. 

The dibasic fatty acid (+)-roccellic acid is ( -)-2S-nlethyl-3R-dodecyl-succinic acid (11) and can be synthesized as a racemate through anodic coupling of lauric acid with erythro-3,4-dimethoxycarbonylpentanoic acid. 

The higher fatty acids and their lactones occurring in lichens can be divided into three groups ) -lactone acid derivatives [nine members, e.g., protolichesterinic acid (1)] dibasic fatty acids [roccellic acid (2)] and tri-basic fatty acids [caperatic, nor- and rangiformic acids (3)]. In addition, two tetrahydroxy fatty acids, e.g., ventosic acid [CH3(CH2)8(CHOH)2-CH2— (CH0H)2(CH2)7C00H] have been reported (Solberg, 1957). All aliphatic lichen acids are optically active. 

Chemically, c. consists (30-50%) of hydroxy- and dibasic fatty acids, which are linked together by lactone and ester groups to form a polymer of complex structure called suberin. Main acids are phel-lonic acid (C22 mono hydroxy) or phloionic acid (Ci8 dihydroxy) and other more hydroxylated or unsaturated acids as well as dibasic acids (- suberic acid). Other components are - lignin (13-18%), - waxes (5-15%) and - tannins. 

The term naphthenic acid, as commonly used in the petroleum industry, refers collectively to all of the carboxyUc acids present in cmde oil. Naphthenic acids [1338-24-5] are classified as monobasic carboxyUc acids of the general formula RCOOH, where R represents the naphthene moiety consisting of cyclopentane and cyclohexane derivatives. Naphthenic acids are composed predorninandy of aLkyl-substituted cycloaUphatic carboxyUc acids, with smaller amounts of acycHc aUphatic (paraffinic or fatty) acids. Aromatic, olefinic, hydroxy, and dibasic acids are considered to be minor components. Commercial naphthenic acids also contain varying amounts of unsaponifiable hydrocarbons, phenoHc compounds, sulfur compounds, and water. The complex mixture of acids is derived from straight-mn distillates of petroleum, mosdy from kerosene and diesel fractions (see Petroleum). 

Dibasic salts of dicyclopentadiene dicarboxylic acid are claimed to be active as corrosion inhibitors [444], Certain salts of fatty acids (metal soaps), together with benzotriazole, are claimed to give synergistic effects for corrosion in antifreeze-agent formulations [446]. 

Fatty Acid Process In Fatty Acid Process the oil is hydrolysed to yield a fatty acid. A mixture of fatty acid, "dibasic acid and polyalcohol" are heated at 200-240°C in inert atmosphere. Sometimes small quantities of xylene is used as solvent. 

The liquid phases of polar columns are usually the heat-stable polymers of ethyleneglycol and the dibasic acids, succinic or adipic (Table 12.13). Fatty acids are separated on the basis of both chain length and the degree of unsaturation and some columns are capable of resolving fatty acids with the same chain length but different numbers of double bonds (0-6). The saturated fatty acids show the shortest retention times followed by the monoenoic, dienoic, etc. (Figure 12.19). 

Elforts have been made to characterize the nature and content of individual components that are present in the low-molecular-mass fraction of the total mill effluents, which include the spent chlorination and alkali extraction stage liquors [2,4]. Approximately 456 types of compounds have been detected in the conventional bleach effluents, of which 330 are chlorinated organic compounds [22]. The compounds may be lumped into three main groups, namely, acidic, phenolic, and neutral (Table 2). Acidic compounds are further divided into the five categories of acids fatty, resin, hydroxy, dibasic, and aromatic acids. The most important fatty acids are formic and acetic acids. The dominant resin acids are abietic and dehydroabietic acids. Among the hydroxy acids identified, glyceric acid predominates. Dibasic acids such as oxalic, malonic, succinic, and mafic acids are derived from the lignin and carbohydrate fraction... 

The first period of scientific work upon returning to Odessa was devoted to study of stereoisomerism of dibasic carboxylic acids, resulting in the discovery of the known Hell-Volgard-Zelinsky method of a-bromi-nation of fatty acids. 

Kekul6 1 advanced a theory based upon the phenomena of decomposition and from this deduced certain formulae which make it possible to predict the nature of the products resulting from the electrolysis of monobasic and dibasic acids of the fatty-acid series. Since, however, the reaction is influenced by the slightest variation of conditions, his formulae hold good only in the case of the decomposition of perfectly pure substances, a condition seldom met with in practice. 

Polyester A resin formed by the reaction between a dibasic acid and a dihydroxy alcohol, both organic. Modification with multi-functional acids and/or bases and some unsaturated reactants permit crosslinking to thermosetting resins. Polyesters modified with fatty acids are called alkyds. 

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 (/). 

Dimer acids. Dimer acids are produced by heating monoene or diene fatty acids (e.g., tall oil acids, a byproduct of wood pulping) with a cationic clay catalyst (92). Typical conditions are 4% montmoriUonite at 230°C for 4—8 hours. After distillation, the product is a complex mixture of acyclic, cyclic, and bicyclic dimers along with some trimer. Dimer acids are dibasic and react with diamines and tria-mines to give polyamides. Imidazole derivatives are used as corrosion inhibitors and esters as lubricants. 

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