Fatty acids sulfur-containing

C-21 dicarboxyhc acids are produced by Westvaco Corporation in Charleston, South Carolina in multimillion kg quantities. The process involves reaction of tall oil fatty acids (TOFA) (containing about 50% oleic acid and 50% hnoleic acid) with acryhc acid [79-10-7] and iodine at 220—250°C for about 2 hours (90). A yield of C-21 as high as 42% was reported. The function of the iodine is apparendy to conjugate the double bond in linoleic acid, after which the acryhc acid adds via a Diels-Alder type reaction to form the cycHc reaction product. Other catalysts have been described and include clay (91), palladium, and sulfur dioxide (92). After the reaction is complete, the unreacted oleic acid is removed by distillation, and the cmde C-21 diacid can be further purified by thin film distillation or molecular distillation. 

The extracted mixture of phenolic compounds, usually referred to by the trade designation of cresylic acids, was essentially free of fatty acids but contained appreciable quantities of thiophenols. Several methods were found effective in minimizing the content of sulfur-containing impurities. 

Lipids are composed of fatty acids that contain both highly hydrophobic and hydrophilic regions. Simple lipids, also referred to as glycerides, are made of three fatty acids bonded to C3 alcohol glycerol. Complex lipids are simple lipids with nitrogen, phosphorus, sulfur, or other small hydrophilic compounds. One example is phospholipids, which have a major structural role in cellular membranes. 

Commonly utilized starting transition metal materials are oxides, halides, salts of fatty acids, complexes containing sulfur, etc. The role of the reducing agents is to lower the oxidation state of a metal and not to reduce the compound to an active metallic phase because this would, in most cases, lead to the inhibition of the reaction as shown by thermodynamic calculations. This point is also indicated by the formation of carbonyl derivatives possessing CO and other coordinating ligands as intermediates. 

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). 

To overcome these difficulties, drilling fluids are treated with a variety of mud lubricants available from various suppHers. They are mostly general-purpose, low toxicity, nonfluorescent types that are blends of several anionic or nonionic surfactants and products such as glycols and glycerols, fatty acid esters, synthetic hydrocarbons, and vegetable oil derivatives. Extreme pressure lubricants containing sulfurized or sulfonated derivatives of natural fatty acid products or petroleum-base hydrocarbons can be quite toxic to marine life and are rarely used for environmental reasons. Diesel and mineral oils were once used as lubricants at levels of 3 to 10 vol % but this practice has been curtailed significantly for environmental reasons. 

Sulfoxides occur widely in small concentrations in plant and animal tissues, eg, aHyl vinyl sulfoxide [81898-53-5] in garlic oil and 2,2 -sulfinylbisethanol [3085-45-8] as fatty esters in the adrenal cortex (1,2). Homologous methyl sulfinyl alkyl isothiocyanates, which are represented by the formula CH3SO(CH2) NCS, where n = 3 [37791-20-1], 4 [4478-93-7], 5 [646-23-1], 8 [75272-81-0], 9 [39036-83-4], or 10 [39036-84-5], have been isolated from a number of mustard oils in which they occur as glucosides (3). Two methylsulfinyl amino acids have also been reported methionine sulfoxide [454-41-1] from cockroaches and the sulfoxide of i -methylcysteine, 3-(methylsulfinyl)alaiiine [4740-94-7]. The latter is the dominant sulfur-containing amino acid in turnips and may account in part for their characteristic odor (4). 

Sulfonation of castor oil using anhydrous SO yields a product having better hydrolytic stabiUty than that from the sulfuric acid reaction. The organically combined SO is low compared to the amount of SO introduced to the reaction the final product contains only 8.0—8.5 wt % combined SO although 17 wt % SO is added. The product contains less inorganic salts and free fatty acids than the sulfuric acid product (36). 

Dimerized fatty acid thioesters (with a dithiol) in combination with fatty amines are sulfur-containing corrosion inhibitors [888]. The corrosion inhibitor solvent is preferably a hydrocarbon. 

One of the most significant differences between Arabica and Robusta coffees is in the caffeine content. Robusta coffees contain almost twice the caffeine found in Arabica coffees. There are some other differences recognized thus far Robustas contain almost no sucrose and only very small amounts of the kaurane and furokaurane-type diterpenes they contain higher proportions of phenols, complex carbohydrates (both soluble and hydrolyzable), volatile fatty acids on roasting, and sulfur compounds, all in comparison with Arabicas. References to these distinctions can be found in Chapter 6 of this book. 

In contrast to the other large cats, the urine of the cheetah, A. jubatus, is practically odorless to the human nose. An analysis of the organic material from cheetah urine showed that diglycerides, triglycerides, and free sterols are possibly present in the urine and that it contains some of the C2-C8 fatty acids [95], while aldehydes and ketones that are prominent in tiger and leopard urine [96] are absent from cheetah urine. A recent study [97] of the chemical composition of the urine of cheetah in their natural habitat and in captivity has shown that volatile hydrocarbons, aldehydes, saturated and unsaturated cyclic and acyclic ketones, carboxylic acids and short-chain ethers are compound classes represented in minute quantities by more than one member in the urine of this animal. Traces of 2-acetylfuran, acetaldehyde diethyl acetal, ethyl acetate, dimethyl sulfone, formanilide, and larger quantities of urea and elemental sulfur were also present in the urine of this animal. Sulfur was found in all the urine samples collected from male cheetah in captivity in South Africa and from wild cheetah in Namibia. Only one organosulfur compound, dimethyl disulfide, is present in the urine at such a low concentration that it is not detectable by humans [97]. 

The fat refining and bleaching operation is carried out to remove impurities that would cause color and odor in the finished soap. The wastewater from this source has a high soap concentration, treatment chemicals, fatty impurities, emulsified fats, and sulfuric acid solutions of fatty acids. Where steam is used for heating, the condensate may contain low-molecular-weight fatty acids, which are highly odorous, partially soluble materials. 

Subsequent epidemiological studies have supported the association between better health and long-term consumption of diets rich in foods of plant origin. " However, whether this is because such diets minimize exposure to deleterious substances (e.g., oxidized cholesterol, pyrolysis mutagens, salt, saturated fat, etc.), or maximize intake of certain beneficial nutrients (e.g., isothiocyanates and other sulfur-containing plant constituents, mono-unsaturated fatty acids, and poly-unsaturated fatty acids, PPT, poly acetylenes, selenium, terpenes, etc.) or some combination as advocated in the Polymeal concept, remains unknown. " An in vitro study indicates that there may be mechanistic basis for true synergy between PPT and isothiocyanates. ... 

Black oil should be a pure petroleum product free from fatty oils, fatty acids, resins, soaps, or other nonhydrocarbons. Sediment and sludge, insoluble in paraffin naphtha, should not exceed 12% when determined by the methods of the American Association of State Highway Officials. The product should be a distilled or fractionated oil, and should contain no oil-well water or residue therefrom. The product should be free of or contain no more than traces of naphthenic acids, naphthenes, mercaptans, soluble sulfide, and volatile sulfur derivatives. The oil should flow freely from the tank car at temperatures above 32 F. 

The fatty acid-like leukotrienes derived from the addition of glutathione to products of the lipoxygenase branch of the arachidonic cascade are closely associated with manifestations of asthma. Many compounds designed to antagonize leukotrienes at the receptor level incorporate long alkyl chains to mimic the leukotrienes backbone in addition to the sulfur-containing moieties that stand in for glutathione. The reaction... 

Most of the sulfur in plants occurs in proteins, especially in the amino acids cysteine and methionine. Other essential compounds that contain sulfur are coenzyme A, a compound essential for cellular respiration and for the synthesis and breakdown of fatty acids, and the vitamins thiamine and biotin. Sulfur can be absorbed by leaves as gaseous sulfur dioxide, S02, an environmental pollutant released from active volcanoes and from the burning of wood or fossil fuels. 

A number of nitrogen- and sulfur-containing heterocyclic compounds are effective corrosion inhibitors (62MI11502), the imidazolines and the benzotriazoles being particularly important types. The imidazolines are derived from ethyleneamines by reaction with fatty acids the free bases (53), the fatty acid salts (54), and various derivatives obtained by reaction with anhydrides, isocyanates or alkyl halides (55) are effective inhibitors. 

Each synthetase module contains three active site domains The A domain catalyzes activation of the amino acid (or hydroxyacid) by formation of an aminoacyl- or hydroxyacyl-adenylate, just as occurs with aminoacyl-tRNA synthetases. However, in three-dimensional structure the A domains do not resemble either of the classes of aminoacyl-tRNA synthetases but are similar to luciferyl adenylate (Eq. 23-46) and acyl-CoA synthetases.11 The T-domain or peptidyl carrier protein domain resembles the acyl carrier domains of fatty acid and polyketide synthetases in containing bound phos-phopantetheine (Fig. 14-1). Its -SH group, like the CCA-terminal ribosyl -OH group of a tRNA, displaces AMP, transferring the activated amino acid or hydroxy acid to the thiol sulfur of phosphopan-tetheine. The C-domain catalyzes condensation (peptidyl transfer). The first or initiation module lacks a C-domain, and the final termination module contains an extra termination domain. The process parallels that outlined in Fig. 21-11.1... 

Purity was confirmed by gel-filtration using a HPLC column packed with Asahipak GS-520HQ and elution with 100 mM sodium phosphate buffer containing 300 mM sodium chloride (pH 6.7). The content of total protein, total sugars, uronic acids, sulfates, nucleic acids, phosphate or fatty acids was assayed by the BCA [32] and Lowry method [33], the phenol-sulfuric acid method [34], the Blumenkrantz method [35], nephelometry [36], absorption at 260 nm, the Bartlett method [37] and the GLC method after methyl-esterification [38], respectively. 

Most of the other products found in irradiated meat volatiles except those containing sulfur or aromatic rings may also be accounted for by mechanisms associated with alkyl free radical formation in the fat. Oxygenated compounds are far less abundant than hydrocarbons, but appreciable amounts of a homologous series of n-aliphatic alcohols up to hexanol are found. Of these, only ethanol is detected in the unirradiated controls. Since the water content of meat averages nearly 60%, the formation of alcohols may be thought to occur by reaction of the alkyl free radical with water. Such a mechanism is supported by the fact that only traces of alcohols are found in irradiated dry butterfat and were undetected in irradiated triglycerides or methyl esters of fatty acids. 

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