Long-chain carboxylates

Electron tunnelling tlirough monolayers of long-chain carboxylic acids is one aspect of interest since it was assumed tliat such films could be used as gate electrodes in field-effect transistors or even in devices depending on electron tunnelling [24, 26, 35, 36, 37 and 38]- It was found, however, tliat tlie whole subject depends critically on... 

FIGURE 19 6 Space filling model of a micelle formed by association of car boxylate ions derived from a long chain carboxylic acid The hydrocarbon chains tend to be on the inside and the carboxylate ions on the surface where they are in contact with water mole cules and metal cations... 

Fats and oils are naturally occurring mixtures of glycerol tnesters Fats are mixtures that are solids at room temperature oils are liquids The long chain carboxylic acids obtained from fats and oils by hydrolysis are known as fatty acids... 

Esters can participate m hydrogen bonds with substances that contain hydroxyl groups (water alcohols carboxylic acids) This confers some measure of water solubil ity on low molecular weight esters methyl acetate for example dissolves m water to the extent of 33 g/100 mL Water solubility decreases as the carbon content of the ester increases Fats and oils the glycerol esters of long chain carboxylic acids are practically insoluble m water... 

Ester hydrolysis in base is called saponification, which means soap making Over 2000 years ago the Phoenicians made soap by heating animal fat with wood ashes Animal fat is rich m glycerol triesters and wood ashes are a source of potassium car bonate Basic hydrolysis of the fats produced a mixture of long chain carboxylic acids as their potassium salts... 

Potassium and sodium salts of long chain carboxylic acids form micelles that dissolve grease (Section 19 5) and have cleansing properties The carboxylic acids obtained by saponification of fats are called fatty acids... 

Acetyl coenzyme A is the biosynthetic precursor to the fatty acids, which most often occur naturally as esters Fats and oils are glycerol esters of long chain carboxylic acids Typically these chains are unbranched and contain even numbers of carbon atoms... 

Hydrolysis of animal fats in the presence of strong base leads to glycerol and salts of long-chain carboxylic acids. The latter are known as soaps . 

Waxes are mixtures of esters of long-chain carboxylic acids with long-chain alcohols. The carboxylic acid usually has an even number of carbons from 16 through 36( while the alcohol has an even number of carbons from 24 through 36. One of the major components of beeswax( for instance, is triacontyl hexadecanoate, the ester of the C30 alcohol triacontanol and the C16 acid hexa-... 

Wax (Section 27.1) A mixture of esters of long-chain carboxylic acids with long-chain alcohols. 

The relative amounts of LDL and HDL cholesterol in your bloodstream depend, at least in part, on your diet In particular, they depend on the total amount and the type of fat that you eat. Fats (triglycerides) are esters of glycerol with long-chain carboxylic acids. The general structure of a fat can be represented as... 

The cleaning action of soaps and detergents relies on the like-dissolves-like rule. Soaps are the sodium salts of long-chain carboxylic acids, including sodium stearate (3). 

Lithium compounds are used in ceramics, lubricants, and medicine. Small daily doses of lithium carbonate are an effective treatment for bipolar (manic-depressive) disorder but scientists still do not fully understand why. Lithium soaps—the lithium salts of long-chain carboxylic acids—are used as thickeners in lubricating greases for high-temperature applications because they have higher melting points than more conventional sodium and potassium soaps. 

Hydroxylation of long-chain carboxylic acids, amides, and alcohols—but not the esters or the corresponding alkanes—at the w-l, (0-2, and (o-3 positions by a soluble enzyme system from Bacillus megaterium (Miura and Fulco 1975 Narhi and Fulco 1986,1987). 

Propionate, Succinate, and Long-Chain Carboxylic Acids... 

This process of crystalHzation using charges was extended to other systems using as an alternative mixtures of amines and long chain carboxylic acids. In this way, super-lattices of nanorods of cobalt and of nanocubes of iron were prepared (vide infra). 

The results of experiments with crude oil fractions in this study also suggest that several species were present in reaction interface. There are mainly long chain carboxylic acids. The difference in size and structure is expected to give them different pka values. As a result, different surface activity (i.e., IFT value) is obtained with different levels of alkali concentration. Crude oil fractions with lower surface activity only yield surface inactive salts that may appear as precipitates at the interface. 

The third general classification of solution synthesis approaches used for inorganic electronic thin film fabrication is referred to as metallo-organic decomposition, or MOD for short.23-29,37,38,85 Historically long-chain carboxylate compounds, such as lead 2-ethylhexanoate, zirconium neodecanoate, and titanium di-methoxy di-neodecanoate have been used.23-29,85 Both commercially available precursors and in-house synthesized starting reagents have been used. 

The hydrophobic components of many lipids consist of either isoprenoids or fatty acids and their derivatives 34 Isoprenoids have the unit structure of a five-carbon branched chain 34 Brain fatty acids are long-chain carboxylic acids that may contain one or more double bonds 34... 

Hydroxide ions react to split ( hydrolyse ) natural esters in the skin to form glycerol (II) and palmitic or stearic acid - a reaction called saponification. Palmitic and stearic acids subsequently react with the base to form the respective long-chain carboxylate anions - which is soap. 

Descalzo AB, Rurack K, Weisshoff H et al (2005) Rational design of a chromo- and fluorogenic hybrid chemosensor material for the detection of long-chain carboxylates. J Am Chem Soc 127 184-200... 

Several types of lipids may be familiar to you. Fats, oils, and some waxes are examples of lipids. Fats are lipids that contain a glycerol molecule, bonded by ester linkages to three long-chain carboxylic acids. Oils have the same structure as fats, but are classified as being liquid at room temperature, while fats are solids at room temperature. Waxes are esters of long-chain alcohols and long-chain carboxylic acids. 

A fat or an oil is produced when three long-chain carboxylic acids, called fatty acids, bond with a glycerol unit to form three ester bonds. (Note that the three fatty acids are not always identical.) A hydrolysis reaction can split these three ester bonds to produce glycerol and a combination of the salts of fatty acids, better known as soap. 

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