Stearic acid description

The major properties of nine of the principal edible vegetable oils are summarized in Tbble 2. For descriptions of the constituent acids, see also Arachidic Acid Capric Acid Caproic Acid Lauric Acid Linoleic Acid Linolenic Acid Myristic Acid Oleic Acid Palmitic Acid and Stearic Acid and Stearates. 

Triacylglycerols are named in various ways. For example, unsaturated fatty acids sometimes are indicated as U and the saturated as S. If glycerol is completely esterified with stearic acid, the resulting monoacid TAG may be designated as SSS, or, more descriptively as StStSt, tristearin, tristearoylglycerol, or glycerol tristearate. 

Description the PhEur 2005 describes diethylene glycol monopalmitostearate as a mixture of diethylene glycol monoesters and diesters of stearic and palmitic acids. It contains not less than 45.0% of monoesters produced from the condensation of diethylene glycol and stearic acid 50 of vegetable or animal origin. Dietbylene glycol monopalmitostearate occurs as a white or almost white waxy solid. 

Tor TAG shorthand description P = palmitic acid S = stearic acid O = oleic acid L = linoleic acid U = unsaturated fatty acid. 

No single description or definition adequately covers all lubricants or lubrication processes. For example, we have seen that a fluid can function as a lubricant by virtue of its viscosity as a liquid. We have also seen that a monomolecular film of stearic acid deposited on a metal surface acts as a lubricant and dramatically reduces the coefficient of friction. A polymeric substance such as polymethylmethacrylate when dissolved in an oil will increase its viscosity and improve its loadcarrying performance in the hydrodynamic lubrication process. Stearic acid dissolved in a carrier oil can effect a strong reduction in the coefficient of friction for metal rubbed against metal. 

Based on the above description, it is no doubt to say that stearic acid along with its derivatives are important and promising materials in biomedical science. With the progress of chemical industry, stearic acid of high purity and quality, or various stearic acids derivatives can be produeed to meet different requirements of medical application. 

Three different fatty acids can occur from 27 different mixed triglycerides. To simplify the description, one- or two-letter abbreviations of fatty acids are used, such as B = butanoic (butyric), D = decanoic (capric or caprinic), H = hexanoic (caproic), L = linoleic, La = lauric, Ln = linolenic, M = myristic, O = oleic, Oc = octanoic (caprylic), P = palmitic, Po = palmitoleic, S = saturated, St = stearic, U = unsaturated and V = vaccenic. For example, the mixed triacylglycerol esterified with palmitic acid in position s -l, with stearic acid in the position sn-2 and oleic acid in the position sn-3 of glycerol is then called l-palmitoyl-2-stearoyl-3-oleoyl-s -glycerol (abbreviated to s -PStO). Racemate is a mixture of s -PStO and and s -OStP in a molar ratio of 1 1... 

In accordance with the general description in Figure 12-1, we know what happens next The second hydrogen transfers over, and the hydrogenated product [stearic acid, CH3(CH2)i6COOH] is released. But notice that this final step is irreversible. Once it occurs, there is no way back to any alkene, cis or trans. Therefore, the cis-trans isomerization pathway must involve only the species we have written in the partial mechanism above. 

This section gives a brief description of other common compounding ingredients such as stearic acid and derivatives, resins, processing aids, and blowing agents. 

Soluble enzymes are much easier to study, so more is known of the first type, but from many studies with a variety of spectroscopic. X-ray and molecular biological techniques, it seems the mechanism of reaction is the same in both types. Although the full story of the enzymes is not yet known, the description here summarizes our present knowledge of membrane-bound fatty acid desaturases found in insects. The description is of a A9-desaturase, the most common type, which converts stearic acid to oleic acid. The location of the double bond is measured from the carboxylate end of the molecule. Palmitic acid with the same enzyme gives palmitoleic acid. If an unnatural Cjy or C19 acid is supplied to the... 

Description C16 palmitic 8.0% palmitoleic C18 stearic 2.0% oleic, 82.0% linoleic, 8.0% linolenic total saturated acids 14% total monounsaturated acids 77% total polyunsaturated acids 9%... 

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