Of glycerol

HC CH(0H) CH20H. optically active. D-glyceraldehyde is a colourless syrup. May be prepared by mild oxidation of glycerol or by hydrolysis of glyceraldehyde acetal (prepared by oxidation of acrolein acetol). DL-glyceraldehyde forms colourless dimers, m.p. IBS-S C. Converted to methylglyoxal by warm dilute sulphuric acid. The enantiomers... 

In the presence of glycerol or mannitol (polyhydroxo compounds) boric acid behaves as a much stronger acid the reaction can be represented as ... 

Dissolve 0 5 ml. of glycerol in 20 ml. of w ater, and add 20 ml. of the above 5% aqueous sodium periodate solution. After 15-20 minutes add 12 ml. of the above 10% ethanolic dimedone solution, and stir well at intervals for another 15 minutes. The addition of the dimedone solution may cause a rapid precipitation of some of the dimedone itself, which is only slightly soluble in water, whereas the formaldehyde-dimedone compound separates more slowly from the solution. 

Use approximately 0 5 ml. of glycerol, and cork the flask A securely when weighing the glycerol by difference, owing to the very hygroscopic nature of the latter. Heat on the water-bath for 60 minutes instead of 30 minutes. Excellent results are obtained by this method if a freshly opened sample of anhydrous glycerol is available a sample which has been exposed to the air for even a short period will absorb sufficient water to give inaccurate results. 

Zymase (a mixture) yeast d-glucose, /-fructose alcohol. CO, and small quantities of glycerol 45-6-5... 

Method 1. Place in a test-tube or small flask 1-3 g. of glycerol and 30 ml. of 10 per cent, sodium hydroxide solution add gradually, with simultaneous shaking, 1-2 g. of benzoyl chloride. Stopper the vessel, shake for several minutes and allow to stand. Decant the solution from the pasty solid and wash the latter with cold water by decantation. Recrystallise the solid tribenzoate from dilute rectified (or methylated) spirit or from light petroleum, b.p. 40-60° the pure compound has m.p. 76°. 

Method 2. Add gradually 2 -5 ml. of benzoyl chloride to a solution of 0-5 g. of glycerol in 5 ml. of pure pyridine, cooled in ice then reflux for 1 hour. Treat the cold mixture with dilute sulphuric acid this dissolves the pyridine salt and precipitates the glycerol tribenzoate. Wash it with sodium bicarbonate solution, followed by water, and recrystaUise as in Method 1. 

Place 170 ml. of concentrated sulphuric acid in a 1-litre three necked flask provided with a stirrer, and add 112 - 5 g. of o-aminophenol, followed by 287 g. of glycerol maintain the temperature below 80° by cooling, if necessary. Keep the mixture in a fluid state by placing the flask on a steam bath. 

I ole is obtained by distilling the ammonium salt of muclc acid, preferably in the presence of glycerol which leads to an improved yield CHOHCHOHCOONH4 CH=CH ... 

Pyrolysis of the methylamine salt (produced by neutralising mucic acid with aqueous methylamlne) in the presence of glycerol yields JV-methylpyrrole ... 

In view of the high reactivity and sensitivity to oxidation of o-phenylone-diamine, the normal experimental conditions of the Skraup reaction are modified the condensation is carried out hi the presence of glycerol, arsenic acid solution and dilute sulphuric acid. 

In a 250 ml. beaker place 15 g. of powdered phthahc anhydride and 10 g. of glycerol mix thoroughly with a thermometer. Heat the mix-tme gently to 150-180° on a wire gauze water vapour is evolved. 

Esters of glycerol called glycerol tnesters tnacylglycerols or triglycerides are abundant natural products The most important group of glycerol tnesters includes those m which each acyl group is unbranched and has 14 or more carbon atoms... 

Tnsteann a tnoctadecanoyl ester of glycerol found in many animal and vegetable fats... 

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... 

Triacylglycerols arise not by acylation of glycerol itself but by a sequence of steps m which the first stage is acyl transfer to l glycerol 3 phosphate (from reduction of dihy droxyacetone 3 phosphate formed as described m Section 25 21) The product of this stage IS called a phosphatidic acid... 

Fats and oils (Section 26 2) Tnesters of glycerol Fats are solids at room temperature oils are liquids Fatty acid (Section 26 2) Carboxylic acids obtained by hydro lysis of fats and oils Fatty acids typically have unbranched chains and contain an even number of carbon atoms in the range of 12-20 carbons They may include one or more double bonds... 

Triacylglycerol (Section 26 2) A derivative of glycerol (12 3 propanetnol) m which the three oxygens bear acyl groups denved from fatty acids... 

Animal fats and vegetable oils are triacylglycerols, or triesters, formed from the reaction of glycerol (1,2, 3-propanetriol) with three long-chain fatty acids. One of the methods used to characterize a fat or an oil is a determination of its saponification number. When treated with boiling aqueous KOH, an ester is saponified into the parent alcohol and fatty acids (as carboxylate ions). The saponification number is the number of milligrams of KOH required to saponify 1.000 g of the fat or oil. In a typical analysis, a 2.085-g sample of butter is added to 25.00 ml of 0.5131 M KOH. After saponification is complete, the excess KOH is back titrated with 10.26 ml of0.5000 M HCl. What is the saponification number for this sample of butter ... 

A typical FAB mass spectrum of glycerol alone, showing a protonated molecular ion at m/z 93 accompanied by decreasing numbers of protonated cluster ions (m/z, 1 + nx92 n = 2, 3, 4,. ..). 

Fats and oils are one of the oldest classes of chemical compounds used by humans. Animal fats were prized for edibiUty, candles, lamp oils, and conversion to soap. Fats and oils are composed primarily of triglycerides (1), esters of glycerol and fatty acids. However, some oils such as sperm whale (1), jojoba (2), and orange roughy (3) are largely composed of wax esters (2). Waxes (qv) are esters of fatty acids with long-chain aUphatic alcohols, sterols, tocopherols, or similar materials. 

HVP products prepared by hydrolysis with HCl contain varying amounts of glycerol chlorohydrins, such as 3-chloro-l,2-propanediol [96-24-2] and l,3-dichloro-2-propanol [96-23-1J, depending on reaction conditions and Hpid contents of the starting material (135). As a result of their toxicides, regulating agencies in many countnes have restncted the contents of these compounds in food. 

Physical properties of glycerol are shown in Table 1. Glycerol is completely soluble in water and alcohol, slightly soluble in diethyl ether, ethyl acetate, and dioxane, and insoluble in hydrocarbons (1). Glycerol is seldom seen in the crystallised state because of its tendency to supercool and its pronounced freesing point depression when mixed with water. A mixture of 66.7% glycerol, 33.3% water forms a eutectic mixture with a freesing point of —46.5°C. 

Since aHyl chloride could be converted to glycerol by several routes, the synthesis of glycerol from propylene [115-07-1] became possible. Propylene can also be oxidized in high yields to acrolein [107-02-8]. Several routes for conversion of acrolein to glycerol are shown in Figure 1. 

The sweet water from continuous and batch autoclave processes for splitting fats contains tittle or no mineral acids and salts and requires very tittle in the way of purification, as compared to spent lye from kettle soapmaking (9). The sweet water should be processed promptly after splitting to avoid degradation and loss of glycerol by fermentation. Any fatty acids that rise to the top of the sweet water are skimmed. A small amount of alkali is added to precipitate the dissolved fatty acids and neutralize the liquor. The alkaline liquor is then filtered and evaporated to an 88% cmde glycerol. Sweet water from modem noncatalytic, continuous hydrolysis may be evaporated to ca 88% without chemical treatment. 

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