Glycerin

Glycerin is a clear include as organic chemicals, nearly colorless liquid having a sweet taste but no odor. Scheele first prepared glycerin in 1779 by heating a mixture of olive oil and litharge. On washing with water, a sweat solution was obtained, giving, on evaporation of the water, a viscose heavy liquid, which the discover called “the sweet principle of facts.” In 1846 Sobrero produced the explosive nitroglycerin for the first time, and in 1868 Nobel, by absorbing it in keselghr, made it safe to handle as dynamite. These discoveries increased the demand for glycerin. This was in part satisfied by the development in 1870 of a method for recovering glycerin and salt from spent soap lyes. Since about 1948, glycerol has been produced from petrochemical raw materials by synthetic processes.

Uses and Economics
The production of crude glycerin is approximately 150 kt/year. Synthetic glycerin furnishes about 40 percent of the market. Glycerin is supplied in several grades, including UPS and CP, grade which are chemically pure, contain not less than 95% glycerol, and are suitable for resins and other industrial products. Yellow distilled is used for certain process where higher purity types are not essential, e.g. as a lubricant in tire molds. Glycerin is employed in making, preserving, softening, and moistening a great many products.

Manufacture
Glycerin may be produced by a number of different methods, of which the following are important:

1. the saponification of glycerides (oils and fats) to produced soap
2. the recovery of glycerin from the hydrolysis, or splitting, of fats and oils to produce fatty acids
3. the chlorination and hydrolysis of propylene and other reactions from petrochemical hydrocarbon