Phloroglucinol

A03AX12

Colorless to pale beige solid

Fixed

215-218 ° C

8.45

• Poorly in water (10 g · l-1 at 20 ° C)
• Soluble in diethyl ether, ethanol, pyridine,

Attention

4550 mg · kg -1 ( LD50, mouse, oral)

Template: Infobox chemical / molecular formula search available

Phloroglucinol (1,3,5- trihydroxybenzene ) is a derivative of benzene, a trivalent phenol. It crystallizes from aqueous solution as the dihydrate with two molecules of water of crystallization. Hydrochloric acid phloroglucinol solution is used as a detection reagent for lignin. The other two isomers are pyrogallol ( 1,2,3- trihydroxy ) and hydroxyhydroquinone (1,2,4- trihydroxy ).

Representation

Phloroglucinol can be obtained from aqueous solutions in the form of colorless needle crystals, each containing 2 molecules of water of crystallization per molecule phloroglucinol: C6H3 (OH) 3 · 2 H2O. It can be obtained by cleavage of many higher composite plant products such as dragon's blood, gamboge, quercetin, morin or Maklurin.

Properties

Physical Properties

The crystal anhydrous phloroglucinol has a melting point of about 218 ° C; it decomposes before the boiling point is reached. It dissolves readily in alcohol and ether, and tastes very sweet.

Chemical Properties

From Phloroglucingerüst many natural substances derive as flavones and Anthocyanfarbstoffe. Chemically it behaves often as a phenol but as a ketone. With hydroxylamine it forms a trioxime.

Formally, it can therefore also known as ( cyclo) trimer of the ketene ( H2C = C = O) are considered. Phloroglucinol is light sensitive and is, therefore, stored in brown glass bottles.

Use

Hydrochloric acid phloroglucinol solution is used in the paper making for the detection of lignin contained in the pulp. In the presence of lignin in a sample occurs, a red coloration. The carbonyl group of the Coniferylaldehyds contained in the lignin reacts with the phloroglucinol. It is also part of Günzburg reagent - an alcoholic solution of phloroglucinol and vanillin for the detection of the free hydrochloric acid in the gastric juice.

In microscopy, it is used for descaling of bone samples. Phloroglucinol also serves as a reagent for pentoses, pentosans and aldehydes.

Proof

For qualitative analytical detection arises in the bromination with potassium bromide and bromine the Tribromphloroglucin, which has a melting point of 151 ° C.