Copper palmitate

A similar state of affairs holds with copper palmitate as the lubricant. Data such as these provide evidence for the association of the filmforming properties of fatty acids with inhibition of direct asperity contact, low coefficients of friction and smooth sliding. This is the type of behavior to which the term boanda)iy tubA C-atZon is generally understood to apply. 

Figure 10-12. Influence of temperature on the behavior of various film-forming lubricants. (a) Paraffin oil on copper. (b) Octadecyl alcohol on copper. (c) Palmitic acid on cadmium. (d) Copper palmitate on cadmium. From data by Rabinowicz and Tabor [29].

By extension of this argument, with a smeared-on film of palmitic acid we would expect a frictional transition at its melting point of 337 K (64 C). However, for palmitic acid on cadmium the observed coefficient of friction remains low (ii j = 0.05-0.07) up to 388 K (115 C), after which it rises until the friction becomes very irregular at ca. 408 K (135 C). Similar behavior is observed for a smear of copper palmitate on the surface of the cadmium except that the rise of the coefficient of friction with temperatures above the transition is less sharp. The transition temperature agrees satisfactorily with the softening temperature of cop-... 

Peroxy-linked dimers are also formed from linoleate hydroperoxides in the presence of free radical initiators and copper palmitate, and carbon-carbon linked dimers in the presence of copper catalysts. Decomposition of methyl linoleate hydroperoxides at 210°C under nitrogen produces mainly carbon-carbon linked dimers (82%), monomers with loss of diene conjugation, volatile compounds (4-5%) and water. The resulting dimers contain carbonyl and hydroxyl groups and double bonds scattered between carbon 8 and carbon 10. Linoleate hydroperoxides can dimerize by one of the termination reactions discussed in Chapter 1. The termination reactions involving combination of alkyl, alkoxyl, or peroxyl radical intermediates produce dimers with carbon-carbon, carbon ether, or peroxy links. The carbon-carbon and carbon-oxygen linked dimers are favored at elevated temperatures and the peroxy-linked dimers at ambient temperatures. The peroxy-linked dimers may also decompose to the ether-linked and carbon-carbon linked dimers via the corresponding alkyl and alkoxyl radical intermediates. 

Copper Organo-copper compounds with fatty acids Copper palmitate... 

The corrosive activity on copper/lead bearings for typical carboxylic acids, such as decanoic, lauric, palmitic, stearic, and oleic acids, as 1 % w/w solutions in a lubricating oil base stock with excess of hard-core RMs, measured by infrared spectroscopy, supports the observation for the corrosive activity of used lubricating oils. An increase in total acidic number (TAN) is generally either an indication of contamination with acidic combustion products or the result of oil oxidation. Corrosion of bearing metals by used lubricating oils requires the presence of both acids and peroxides and probably takes place by a two-step mechanism. In the first step, the peroxide reacts with the metal to form a metal... 

Figure 2-19 Effect of Copper Concentration on Protective Effect of Antioxidants in Lard. (A) lard + 0.01% BHT, (B) lard + 0.01% ascorbyl palmitate, (C) lard + 0.005% BHT and 0.05% ascorbyl palmi-tate. Source From J. Pokorny, Stabilization of Fats by Phenolic Antioxidants, Can. Inst. Food Sci. Technol. J., Vol. 4, pp. 68—74, 1971.

Copper pin on copper disk, 2.35 N load, sliding speed 1 cm/s. Solutions of palmitic acid in cetane. From data by Tamai and Rightmire [14]. 

Data on the lubrication of copper by palmitic acid obtained by Tamai and Rightmire [14] are given in Table 9-7, The copper specimens were polished, heated for 3 minutes at a temperature of 973 K (700 C) and a pressure of 6.6 Pa (0.05 torr), cooled, and then introduced into the friction apparatus as soon as they had come to room temperature. These are the specimens identified as "fresh" surfaces in Table 9-7, The... 

The levels of palmitic acid, palmitoleic acid, stearic acid and oleic acid increased in both groups, after 4 h of copper-oxidation. While concentrations of cholesteryl oleate, cholesteryl linoleate, cholesteryl arachidonate and cholesteryl docosahexanoate were reduced, following copper stimulated oxidation, in both groups [85]. 

Very few determinations have been made of the total fatty acid content of marine waters. Of the few methods available, a technique which is reported to be reliable is that of extraction of the free acids with chloroform at pH 2 followed by formation of a copper complex and final estimation of the complexed copper by atomic absorption spectrophotometry (Treguer et al., 1972). The free fatty acid contents are reported as palmitic acid equivalents. The method, however, has not yet been widely adopted for routine use. 

Composition of the salt premix. Presence of iron, zinc and copper salts in the same premix reduces efficacy of iodine. The presence of an oxidizing agent such as vitamin A palmitate would help in protecting iodine in I form. 

In principle, ascorbic acid and its salts (sodinm or calcinm ascorbate) are water solnble antioxidants, not widely applicable for lipid systems but extensively nsed in beverages. In aqneons systems containing metals, ascorbic acid may also act as a prooxidant by reducing the metals that become active catalysts of oxidation in their lower valences. However, in the absence of added metals, ascorbic acid is an effective antioxidant at high concentrations. The action of ascorbic acid in lipid autoxidation is dependent on concentration, the presence of metal ions, and other antioxidants. It has been shown that ascorbates can protect plasma and LDL lipids from peroxidative damage, and it may inhibit the binding of copper ions to LDL. " In several countries, ascorbic pahnitate is used in fat containing foods due to its lipid solubility. However whether ascorbic palmitate exerts a better... 

The hepatic uptake of diet-derived copper occurs via the copper transporter 1 (Ctrl), which transports copper with high affinity in a metal-specific, saturable fashion at the hepatocyte plasma membrane (Lee et al., 2001 Klomp et al., 2002). After uptake copper is bound to metallothionein (MT), a cytosolic, low molecular weight, cystein-rich, metal binding protein. MT I and MT II are ubiquitously expressed in all cell types including hepatocytes, and have a critical role to protect intracellular proteins from copper toxicity (Palmiter, 1998 Kelley and Palmiter, 1996). The copper stored in metallothionein can be donated to other proteins. Specific pathways allow the intracellular trafficking and compartmentaUzation of copper, ensuring adequate cuproprotein synthesis while avoiding cellular toxicity (Fig.21.1). 

C6.C12) Alkyl carboxylic acid, trimethylolpropane triester. See Trimethylolpropane tricaprylate/tricaprate (C10-C18) alkylsulfonic acid, sodium salt. See Sodium C10-18 alkyl sulfonate C29-70 carboxylic acids. See C29-70 acid CCA Type C Wood Preservative 50-60%. See Chromate copper arsenate CCC. See Chlormequat chloride Calcium cyanamide Chlorophyllin-copper complex N-(C14-C18) and (C18-C18) unsaturated alkylpropylenediamine C14-C18 and C18-18-unsat. N-(alkyl) propylene diamine. See Tallowaminopropylamine (C18-C18) and (Cl 8) unsaturated alkylcarboxylic acid. See Palmitic/oleic acids (C18-C18) and C18 unsaturated alkyidimethylamine. See Dimethyl oleic-linolenic amine... 

Copper chrome arsenate 37337-53-4 Fosamine ammonium 37340-08-2 Retinyl palmitate 37340-60-6 Rhodafac LO-529 Sodium nonoxynol-6 phosphate 37349-34-1 Calgene PGS-61 Calgene PGS-101 Calgene PGS-K Caprol 3GS... 

In addition to rubber, latex contains 0.3-0.7% ash, 1-2% nitrogenous compounds, 2% resins, and 1-2% sugars and related compounds. The proteins represent most of the nitrogenous compounds in the latex and upon hydrolysis yield alanine, aspartic acid, dihydroxyphenylalanine, glutamic acid, histidine, leucine, ornithine, hydroxyproline, tyrosine, and valine. Lecithin, glycerophosphoric acid, fatty acids (palmitic, stearic, arachidic, oleic, and linoleic), sterols, resin acids, wax, and quebrachitol are some of the other nonrubber constituents. The mineral constituents present in the ash consist of potassium, magnesium with traces of copper, iron, and manganese. 

It has been demonstrated that feeding tallow rich in palmitic, stearic, and oleic acid rednces the saturated fatty acids, Cg to Cjg whereas Cjg.Q and Cjg.j were inaeased in milk [reviewed in (24)]. With health issues such as bovine spongiform encephalopathy (BSE) associated with animal products, it is important that all traces of protein be removed before using animal fat. Although this appears achievable (71), some contaminants such as hair fragments have been found (67). It is also possible to increase CLA content of milk fat by depleting the copper status of the diet (72). 

Two useful syntheses of fatty acids have appeared. Coupling of the chloro-magnesium salts of w-bromoacids with alkyl Grignard reagents via an organo-copper(i) ate complex is shownto be most effective for longer chain acids (e.g. palmitic acid in 94% yield), whereas an efficient route to o -methyl labelled fatty acids proceeds via methyl cadmium chloride (Scheme 5). 

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