Trihydroxy alcohols

The pendant hydroxy groups of ethylene oxide-propylene oxide copolymers of dihydroxy and trihydroxy alcohols may be sulfurized to obtain a sulfurized alcohol additive. This is effective as a lubricant in combination with oils and fats [387,533]. The sulfurized alcohols may be obtained by the reaction of sulfur with an unsaturated alcohol. Furthermore, fatty alcohols and their mixtures with carboxylic acid esters as lubricant components [1286] have been proposed. 

The natural fats and oils are also esters, principally of the trihydroxy alcohol glycerol. Animal fats consist mainly of the glyceryl esters of palmitic acid and stearic acid. Glyceryl oleate, the glyceryl ester of oleic acid, is found in olive oil, whale oil, and the fats of coldblooded animals these fats tend to remain liquid at ordinary tempera-lures, whereas glyceryl palmitate and glyceryl stearate form the solid hits. 

The most common fats are esters composed of the trihydroxy alcohol known as glycerol and long-chain carboxylic acids called fatty acids (see Table 21.5). Tristearin, the most common animal fat, is typical of these substances. 

II. Dihydroxy Alcohols III. Trihydroxy Alcohols IV. Polyhydroxy Alcohols... 

Dihydroxy and trihydroxy alcohols have two and three hydroxyl groups respectively, on their hydrocarbon molecule. For example ... 

Nitroglycerine is prepared by mixing glycerol (trihydroxy alcohol) into a mixture of nitric and sulfuric acids at a cold temperature. 

Fats are the glyceryl esters of fatty acids. Glycerol is the trihydroxy alcohol CH2OH—CHOH—CH>OH (Section 13-3). It combines with three molecules of a fatty acid, such as palmitic acid (Table 13-3), to produce a fat ... 

Nutritional fats and oils are primarily triglycerides, the combination of glycerol (a trihydroxy alcohol) with three fatty acids. The triglyceride formed by the combination of glycerol and stearic acid, for example, is tristearin (Figure 18-9), a principal component of beef fat. Triglycerides differ from one another by their fatty acid side chains. If the side chains contain no double bonds, the triglyceride... 

Natural FATS are solid esters and fatty OILS are liquid esters of the trihydroxy alcohol glycerol. Natural fats and oils contain two or three different carboxylic acid components, each with an even number of carbon atoms ranging from 4 to 26. The saponification of such esters, therefore, yields a mixture of soaps ... 

A good example of difference in molecular requirements for linear and network polymers is the formation of polyesters from dihydroxy or trihydroxy alcohols. As was shown on page 554 for diamines, reaction of a dihydroxy alcohol with a diacid gives a linear copolymer. If a trihydroxy alcohol is used instead, a network copolymer is formed. An example is the class of ALKYD resins (Fig. 26.3), produced from glycerol and phthalic acid, and used as ingredients of paints and varnishes. 

L-Scrrbilol is used in one of the laboratory methods for synthesising the vitamin Ascorbic acid (p. 260). Glycerol, the trihydroxy alcohol corresponding to glycerose, is a characteristic constituent of oils and fats found in animals and plants. 

Aliphatic Alcohols.—Natural fats and oils are esters of the trihydroxy alcohol glycerol the other ahphatic alcohols occur either free as solutes in oils and fats or combined as waxes. Five groups of these lipide alcohols may be recognised, four of which belong to the straight-chain type of compounds. 

Trihydroxy alcohol of the Olycerol Series. Only one member... 

It is characteristic of all these substances that the trihydroxy alcohol glycerol is replaced by the amino dialcohol sphingosine. Sphingosine is a long-chain Ci8 compound that contains a trans double bond, an NH2 group on C atom 2, and two OH groups (on C-1 and C-3). The steric configurations at the centers of asymmetry are indicated in the projection formula shown below. 

In the body, fatty acids are stored as triacylglycerols, also called triglycerides, which are triesters of glycerol (a trihydroxy alcohol) and fatty acids. The general formula of a triacylglycerol follows ... 

Dihydroxy alcohols (diols) and trihydroxy alcohols (triols) are viscous, hygroscopic, high boiling point liquids with a sweetish taste. Some of them are useful as solvents for pharmaceutical use. In the case of diols the two hydroxyl groups are usually attached to different carbon atoms. If the hydroxyl groups are attached to the same carbon an atom of water is eliminated to give a carbonyl compound (Fig. 5.5). There are exceptions to this for example, in the case of chloral hydrate the diol is stabilised by the electron-withdrawing chlorine atoms. 

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