Stearic acid, structure

Butanoic acid has a proportionally larger polar portion and is therefore more soluble in water than stearic acid is. In fact, butanoic acid is miscible with water (will mix with it in any proportion). The much higher proportion of the stearic acid structure that is nonpolar makes it almost insoluble in water. 

The glass surfaces were smooth over large areas [8], and in the rare instances where scratches and abrasions did occur, monolayers of the cerotic and behenic acids continued uninterruptedly over a minor surface defect. Stearic acid structures were not observed to do this. 

There is a fair amount of work reported with films at the mercury-air interface. Rice and co-workers [107] used grazing incidence x-ray diffraction to determine that a crystalline stearic acid monolayer induces order in the Hg substrate. Quinone derivatives spread at the mercury-n-hexane interface form crystalline structures governed primarily by hydrogen bonding interactions [108]. 

FIGURE 8.12 A structure and a space-filling model of a choline sphingomyelin formed from stearic acid. 

Zinc salt of maleated EPDM rubber in the presence of stearic acid and zinc stearate behaves as a thermoplastic elastomer, which can be reinforced by the incorporation of precipitated silica filler. It is believed that besides the dispersive type of forces operative in the interaction between the backbone chains and the filler particles, the ionic domains in the polymer interact strongly with the polar sites on the filler surface through formation of hydrogen bonded structures. 

Fats can be either optically active or optically inactive, depending on their structure. Draw the structure of an optically active fat that yields 2 equivalents of stearic acid and 1 equivalent of oleic acid on hydrolysis. Draw the structure of an optically inactive fat that yields the same products. 

Stearolic acid, C H- Oa, yields stearic acid on catalytic hydrogenation and undergoes oxidative cleavage with ozone to yield nonanoic acid and nonanedioic acid. What is the structure of stearolic acid ... 

Using the Molecules Database on the Web site for this book, examine the structure of tristearin, formed by ilk the condensation of three molecules of stearic acid,... 

Write the structural formula for the product of (a) the reaction of glycerol (1,2,3-trihydroxypropane) with stearic acid, CH5(CH2)16COOH, to produce a saturated fat (b) the oxidation of 4-hydroxybenzyl alcohol by sodium dichromate in an acidic organic solvent. 

Write the condensed structural formulas of the principal products of the reaction that takes place when (a) ethylene glycol, 1,2-ethanediol, is heated with stearic acid, CH,(CH2)i6COOH (b) ethanol is heated with oxalic acid, HOOCCOOH (c) 1-butanol is heated with propanoic acid. 

In 1997, a Chinese research group [78] used the colloidal solution of 70-nm-sized carboxylated latex particles as a subphase and spread mixtures of cationic and other surfactants at the air-solution interface. If the pH was sufficiently low (1.5-3.0), the electrostatic interaction between the polar headgroups of the monolayer and the surface groups of the latex particles was strong enough to attract the latex to the surface. A fairly densely packed array of particles could be obtained if a 2 1 mixture of octadecylamine and stearic acid was spread at the interface. The particle films could be transferred onto solid substrates using the LB technique. The structure was studied using transmission electron microscopy. 

Damle et al. observed that the reduction of the Pd(II) ions in the stearic acid-Ag nanocomposite film leads to the formation of a mixture of individual Ag and Pd nanoparticles as well as particles in the Ag-core/Pd-shell structure. Thermal treatment of the stearic acid-(Ag/Pd) nanocomposite film at 100 °C, however, resulted in the formation of an AgPd alloy [142]. 

Soaps are composed of sodium salts of various fatty acids. These acids include those with the general structure CH3-(CH2) -COOH where n = 6 (caprylic acid), 8 (capric acid), 10 (lauric acid), 12 (myristic acid), 14 (palmitic acid), and 16 (stearic acid). Oleic acid (CH3-(CH2)7-CH=CH-(CH2)7-COOH) and linoleic acid (CH3-(CH2)4-CH=CH- H2-CH=CH-(CH2)7-COOH) are also common soap ingredients. These sodium salts readily dissolve in water, but other metal ions such as Ca2+ and Mg2+ form precipitates with the fatty acid anions. For example, the dissolution of the sodium salt of lauric acid and the subsequent formation of a precipitate of the lauric acid anion with calcium ion is given by... 

Figure 15.14 Study of the sample from the Dogon statuette 71.1935.105.169. (a) Optical microphotograph (b) SEM micrograph showing the layer structure ToF SIMS images of (c) proteins, (d) polysaccharides and (e) stearic acid (f) superposition of the distribution of poly saccharides and stearic acid (see colour Plate 9)...

Crosslinked polymer particles with a rather complex structure, which have also been designated by the name microgels and recommended as components of metal effect paints, consist of carboxyl-terminated oligoesters of 12-hydroxy stearic acid which were reacted with glycidyl methacrylate, subsequently copolymerized with MMA and hydroxymethyl methacrylate and then crosslinked by hydroxy melamine [346]. 

Figure 1. Melting process of a stearic acid monolayer at the air/water interface. The BAM images of the domain structures (a) 41 °C, (b) 45 °C, (c) 47 °C, and (d) at 20 °C after melting.

The FT-IR technique using reflection-absorption ( RA ) and transmission spectra to quantitatively evaluate the molecular orientation in LB films is outlined. Its application to some LB films are demonstrated. In particular, the temperature dependence of the structure and molecular orientation in alternate LB films consisting of a phenylpyrazine-containing long-chain fatty acid and deuterated stearic acid (and of their barium salts) are described in relation to its pyroelectricity. Pyroelectricity of noncentrosymmetric LB films of phenylpyrazine derivatives itself is represented, too. Raman techniques applicable to structure evaluation of pyroelectric LB films are also described. 

Figure 11.1 Structures of commonly occurring saturated fatty acids (i) myristic acid, Ci4 o (ii) palmitic acid, C s-.o (iii) stearic acid, Ci8 0.

Figure 7.7 Structures of some fatty acids and sterols found in archaeological residues. Upper compound octadecanoic acid (stearic acid, Ci8 0), middle compound ds-9-octadecenoic acid (oleic acid, C18 1), lower compound cholesterol.

The common fatty acids have a linear chain containing an even number of carbon atoms, which reflects that the fatty acid chain is built up two carbon atoms at a time during biosynthesis. The structures and common names for several common fatty acids are provided in table 18.1. Fatty acids such as palmitic and stearic acids contain only carbon-carbon single bonds and are termed saturated. Other fatty acids such as oleic acid contain a single carbon-carbon double bond and are termed monounsaturated. Note that the geometry around this bond is cis, not trans. Oleic acid is found in high concentration in olive oil, which is low in saturated fatty acids. In fact, about 83% of all fatty acids in olive oil is oleic acid. Another 7% is linoleic acid. The remainder, only 10%, is saturated fatty acids. Butter, in contrast, contains about 25% oleic acid and more than 35% saturated fatty acids. 

This finding has been replicated several times in clinical studies. Let me cite one example. In a careful metabolic study carried out in 1990, Mensink and Katan determined the plasma LDL/HDL ratio when 10% of the energy from oleic acid was replaced in the diet by either the corresponding trans fat or the corresponding saturated fatty acid, stearic acid. The resulting LDL/HDL ratios were 2.02 on the oleic acid diet, 2.34 on the stearic acid diet, and 2.58 on the trans fatty acid diet. This is one more example of the impact of small structural changes in molecules on their biological properties. 

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