Word Finder - glycerin

definition

The common name for glycerol, glycerin or E422.

Glycerin is also a product of certain kinds of fermentation, especially of the alcoholic fermentation of sugar; consequently it is a constituent of many wines and other fermented liquors.

It is obtainable from most natural fatty bodies by the action of alkalis and similar reagents, whereby the fats are decomposed, water being taken up, and glycerin being formed together with the alkaline salt of some particular acid (varying with the nature of the fat).

Owing to their possession of this common property, these natural fatty bodies and various artificial derivatives of glycerin, which behave in the same way when treated with alkalis, are known as glycerides.

In the ordinary process of soap-making the glycerin remains dissolved in the aqueous liquors from which the soap is separated.

Berthelot, and many other chemists, from whose researches it results that glycerin is a trihydric alcohol indicated by the formula C 3 H 5 (OH) 3j the natural fats and oils, and the glycerides generally, being substances of the nature of compound esters formed from glycerin by the replacement of the hydrogen of the OH groups by the radicals of certain acids, called for that reason "fatty acids."

Some other glycerides isolated from natural sources are analogous in composition to tristearin, but with this difference, that the three radicals which replace hydrogen in glycerin are not all identical; thus kephalin, myelin and lecithin are glycerides in which two hydrogens are replaced by fatty acid radicals, and the third by a complex phosphoric acid derivative.

According to Louis Pasteur, about oth of the sugar transformed under ordinary conditions in the fermentation of grape juice and similar saccharine liquids into alcohol and other products becomes converted into glycerin.

The simplest modes of preparing pure glycerin are based on the saponification of fats, either by alkalis or by superheated steam, and on the circumstance that, although glycerin cannot be distilled by itself under the ordinary pressure without decomposition, it can be readily volatilized in a current of superheated steam.

Commercial glycerin is mostly obtained from the "spent lyes" of the soap-maker.

Evaporation and subsequent distillation under a high vacuum gives crude glycerin.

The impure glycerin obtained as above is purified by redistillation in steam and evaporation in vacuum pans.

Its solvent power is also utilized in the production of various colouring fluids, where the colouring matter would not dissolve in water alone; thus aniline violet, the tinctorial constituents of madder, and various allied colouring matters dissolve in glycerin, forming liquids which remain coloured even when diluted with water, the colouring matters being either retained in suspension or dissolved by the glycerin present in the diluted fluid.

Glycerin is also employed in the manufacture of formic acid.

In its medicinal use glycerin is an excellent solvent for such substances as iodine, alkaloids, alkalis, &c., and is therefore used for applying them to diseased surfaces, especially as it aids in their absorption.

Given by the mouth glycerin produces purging if large doses are administered, and has the same action if only a small quantity be introduced into the rectum.

Glycerin is useless as a food and is not in any sense a substitute for cod-liver oil.

Glycerin when treated with hydrochloric acid gives propenyl dichlorhydrin, which may be oxidized to s-dichloracetone.

In preparing lead plaster by boiling olive oil with oxide of lead and a little water - a process palpably analogous to that of the soap-boilerhe obtained a sweet substance which, called by himself " Olsiiss " (" principium dulce oleorum "), is now known as " glycerin."

These discoveries of Geoffroy and Scheele formed the basis of Chevreul's researches by which he established the constitution of oils and the true nature of soap. In the article Oils it is pointed out that all fatty oils and fats are mixtures of glycerides, that is, of bodies related to the alcohol glycerin C 3H5(OH)3 i and some fatty acid such as palmitic acid (C 16 H 31 0 2)H.

The corresponding decomposition of a glyceride into an acid and glycerin takes place when the glyceride is distilled in superheated steam, or by boiling in water mixed with a suitable proportion of caustic potash or soda.

The soap solution which results from the combination forms soap-size and is a mixture of soap with water, the excess alkali, and the glycerin liberated from the oil.

In curd soaps, however, which form the basis of most household soap, the uncombined alkali and the glycerin are separated by " salting out, " and the soap in this condition contains about 30% of water.

Soaps made by this process contain the glycerin originally present in the oil, but, in view of their liability to contain free alkali and unsaponified oil, the process has been largely given up.

Glycerin soap ordinarily consists of about equal parts of pure hard soap and glycerin (the latter valuable for its emollient properties).

The soap is melted by heat, the glycerin is stirred in, and the mixture strained and poured into forms, in which it hardens but slowly into a transparent mass.

With excess of glycerin a fluid soap is formed, soap being soluble in that body, and such fluid soap has only feeble lathering properties.

Soap containing small proportions of glycerin, on the other hand, forms a very tenacious lather, and when soap bubbles of an enduring character are desired glycerin is added to the solution.

The complete analysis involves an examination of the fatty matter, of the various forms in which the alkalis are present - free and combined glycerin, &c.

A new and energetic spirit was introduced by Scheele; among other discoveries this gifted experimenter isolated and characterized many organic acids, and proved the general occurrence of glycerin (Olsiiss) in all oils and fats.

Owing to their want of adhesiveness, they are, however, usually mounted on glass as microscopic slides, either in glycerin jelly, Canada balsam or some other suitable medium.

Some fusel oil, glycerin and succinic acid appear to be formed simultaneously, but in small amount.

There is present in the seeds an enzyme which rapidly decomposes the oil if the seeds are crushed and kept, setting free a fatty acid and glycerin.

That quinine, chloroform, glycerin, alcohol, with others, had no attractive influence on them - negative chemiotaxis.

The neutral fats are composed of fatty acids and glycerin.

Some glycerin may be re-formed, but with very strong alkaline solutions little of the glycerin molecule escapes destruction, oxalic acid and several other products resulting.

Calcium or potassium sulphides and potassium hydrosulphides completely reduce nitroglycerin to glycerin, some of the sulphur being oxidized and some precipitated.

Hydriodic acid reduces it to glycerin and nitric oxide.

The trioses are the aldehyde and ketone mentioned above as oxidation products of glycerin.

Instances of its application are found in the separation of orthoand para-nitrophenol, the o-compound distilling and the p- remaining behind; in the separation of aniline from the mixture obtained by reducing nitrobenzene; of the naphthols from the melts produced by fusing the naphthalene monosulphonic acids with potash; and of quinoline from the reaction between aniline, nitrobenzene, glycerin, and sulphuric acid (the product being first steam distilled to remove any aniline, nitrobenzene, or glycerin, then treated with alkali, and again steam distilled when quinoline comes over).

When heated with glycerin to ioo C. it yields formic acid and carbon dioxide; above this temperature, allyl alcohol is formed.

A dilute potash readily emulsionizes fats, and on boiling saponifies them with formation of a soap and glycerin.

A lotion containing ten minims of the dilute acid to an ounce of water and glycerin will relieve itching due to any cause; and is useful in some forms of neuralgia.

It is a most perfect non-conductor of electricity, and in its dry state the fibres frequently get so electrically excited as to seriously interfere with their working, so that it becomes necessary to moisten them with glycerin or soapy solutions.

This occurs in combination with glycerin, constituting the greater part of the bulk of the oil.

The latter portion, about Io% of the weight of the nutmegs, consists chiefly of myristin, which is a compound of myristic acid, C 14 H 28 0 2, with glycerin.

At the same time various subsidiary products such as glycerin, succinic acid, small quantities of higher alcohols, volatile acids and compound esters are produced.

The sugar, as we have seen, has disappeared, and alcohol, glycerin and other substances have been formed.

The normal proportion of glycerin varies between 7 and 14 parts for every 100 parts of alcohol in the wine, but even these limits are frequently not reached or exceeded.

These comprise gummy and albuminous matters, acid, salts, glycerin and other matters of which we have so far little knowledge.

Although these old wines may contain absolutely a very large quantity of acid, they may not appear acid to the palate inasmuch as the other constituents, particularly the glycerin and gummy matters, will have likewise increased in relative quantity to such an extent as to hide the acid flavour.