Phenylhydrazine
- Hydrazinobenzol
- Monophenylhydrazin
Yellowish to reddish-brown liquid
Liquid
1.1 g · cm -3
19.6 ° C (24 ° C for the hemihydrate )
244 ° C ( partial decomposition )
6 Pa at 20 ° C.
- Well in water (145 g · l-1 at 25 ° C)
- Miscible with ethanol, ether, chloroform, benzene and acetone
Risk
188 mg · kg -1 ( LD50, rat, oral)
Template: Infobox chemical / molecular formula search available
Phenylhydrazine is a chemical compound selected from the group of the hydrazine derivatives. It is a yellowish liquid which increasingly turns a dull red to reddish brown in air.
History
Phenylhydrazine was studied as the first hydrazine derivative by Emil Fischer in 1875. He put it by reducing Phenyldiazoniumsalzen with sulfite dar. Fischer phenylhydrazine used to study the structure of carbohydrates by formation of hydrazones from the aldehyde group of the sugar.
Occurrence
Phenylhydrazine occurs naturally in some plants ( laurel tree, legumes) ago.
Production and representation
Phenylhydrazine is obtained commercially by diazotization of aniline followed by reduction of the diazonium cation, for example by sodium sulfite. In 1998, the production rate was 6650 tonnes in Western Europe.
Properties
Phenylhydrazine forms monoclinic crystals, melting at room temperature to give an oily liquid. It decomposes at a temperature greater than 260 ° C and its vapor is 3.73 times heavier than air. It is a strong reducing agent and readily soluble in water.
Use
Phenylhydrazine is used as intermediate for the preparation of indoles, which in turn are intermediates for the synthesis of various dyes, agricultural chemicals and pharmaceuticals. It also serves as a starting material for preparing developers for photography.
Furthermore, it can be used as reagent for the detection or identification of compounds with carbonyl groups serve (formation of phenylhydrazones or osazones ). The use of phenylhydrazine as a laboratory chemical (analytical reagent for aldehydes, ketones and sugar by the formation of well- crystallized phenylhydrazones or osazones, for the detection of molybdenum and other metals ) is connected to a derivatization.
Safety
Phenylhydrazine is self-igniting when it is dirty or in contact with materials with large surface area ( eg cleaning wool or sand) comes. His Fumes can combine with air to form an explosive mixture when heated above its flash point (89 ° C). Phenylhydrazine is considered to be a carcinogen, is a strong poison blood ( methemoglobin formation ) and on the skin caused eczema. Moreover, it leads to irreversible damage of the blood pigment and the erythrocytes.