The glycerol or the glycerin (C₃H₈O₃) is a Polyol. Its official name is the propan-1,2,3-triol (or 1,2,3-propanetriol ). It is a triol, it has 3 functions alcohol

Its developed Formule planes is:

Its semi-developed Formule is:

History

In 1783, the Chimiste Swedish Carl Wilhelm Scheele obtains glycerol while making boil Olive oil with Oxide lead.

In 1823, the Chimiste French Eugene Chevreul shows that the greasy Substance is formed of a combination between glycerol and the fatty-acids.

Physical properties

The glycerol is appeared as a liquid transparent, viscous, colorless, odorless, nontoxic and with the sweetened taste.

The glycerol can dissolve in the polar solvents thanks to its 3 hydroxyl groups. It is thus soluble in the Eau and the ethanol

Chemical properties

In the living organisms, the glycerol is component important Glycéride S (Graisse S and Huile S) and Phospholipide S. When the body uses the greases stored as energy source, of glycerol and from the fatty-acids are released in blood.

Dehydration

It is made hot, in the presence of hydrogénosulfite potassium (KHSO₃) produced Acroléine according to the reaction:

Esterification

It leads to (mono, di or sorting) Glycéride S. Consulter the article in connection with the Glycéride S.

Synthesis

The glycerol is formed during the alcoholic Fermentation grape must during the production of the Vin.

The glycerol is a by-product of the reaction of Saponification, of which the original intention is to manufacture Savon starting from fat contents Animal are or Végétal are. This reaction is written:

greasy Substance + Soda --> Soap + glycerol

The glycerin is a by-product of the cross esterification of Huile S vegetable during the production of methyl plant oil esters (EMHV) which are used as Carburant S under the denomination of Biodiesel or Diester.

Use

Drugs

• Hydrating which improves the consistency and lubrication of the pharmaceutical preparations
• Utilisé in the Suppositoire S, Sirop S against the Toux (Expectorant S).

Cosmetics

• In the Cosmetic S, the glycerol is often used like hydrating agent, Solvant and Lubrifiant and agent of extinction sets fire to.
• It has better taste and is more Soluble that the Sorbitol which often replaces it.
• Used in the Toothpaste S, the baths of mouth, the hydrating creams, the products capillary and the Soap S
• Composing of the Soap S with glycerin, in particular the household soaps of which separation by heights of glycérineuses water pleasing to the finalization of this product.

Food

• Used for its sweetened taste, to retain moisture and like solvent (E422).

Wine

• the glycerol, formed at the beginning of the alcoholic fermentation of the Must (glyceropyruvic Fermentation), gives to the wine its consistency .

• the Sucre S transform into Pyruvic acid and glycerol.

C₆H₁₂O₆ - > CH₂OH-CHOH-CH₂OH + CH₃-CO-COOH.

• the first 50 G of fermented sugar give more half of the content glycerol of the wine. Its formation depends on the initial quantity of sugar, of the nature of the Levure S and the conditions of fermentation: temperature, acidity, ventilation, sulphiting. The proportion of glycerol is relatively constant: it varies from 6 to 10 G for 100 G of alcohol. However in the white wines liqueur-like coming from rotted grapes (Botrytis), the contents glycerol often exceed much these proportions. The Sauternes are sweetened and soft with the palate. The glycerol is also in the red wines (good Burgundy S). The formation of `cast' or tears on the walls of glass after agitation n´est not an index of quality due to glycerol but is explained by a difference d evaporation and of capillary tension between l´eau and l´alcool (l´effet Marangoni).

Chemistry

• It is one of the main components of the manufacture of the Nitroglycérine.
• It is also one of the essential components to make bubbles of soap.
• One can make Feu without match if one mixes glycerol with Permanganate of potassium (KMnO4) out of powder. The reaction is very slow at the beginning (one observes nothing during the 30 first second), then it is so much Exothermique that it ignites permanganate: one sees flames violets due to the ion MnO4- and flames oranges due to the ion K+. Thanks to this heat emission, the reaction speed which was weak becomes very large.
• In great quantity the reaction can reach higher temperatures with 1000°C.
• not to add substances with this reaction without knowing their properties. For example powder aluminum mixed with KMnO4 + Glycérol makes the reaction very explosive.

Cellophane

• Plasticizing in the Cellophane.

Other applications

• Plasticizer and lubricating in the manufacture of the Papier
• Lubricates and softens wire and the fabrics
• Utilisé in the fluids antifreezing
• Appliqué to a mirror, it also avoids the appearance of mist
• Sert for special effects such as simulation of perspiration or the smoke-producing ones.
• Is also used for the bubbles as soap
• Sert in aeronautics to lubricate drinking water pipings because of its properties nonpolluting

Random links:

Lake Bolsena | Viso mount | ISO 3103 | NIDLE | Adeline Lamarre