Picryl chloride
Light yellow crystalline needles
Fixed
1.797 g · cm -3 ( 20 ° C)
83 ° C.
Practically insoluble in water, slightly soluble in ethanol and benzene, slightly more soluble in diethyl ether
Risk
Template: Infobox chemical / molecular formula search available
The trinitrochlorobenzene (2,4,6- trinitrochlorobenzene, picryl chloride ) is a solid chemical compound having explosive properties. It is derived from both the chlorobenzene and nitrobenzene from. The structure consists of a benzene ring with attached chlorine ( -Cl) and three nitro groups (- NO2) as a substituent. The name picryl chloride originates from the early days of organic chemistry (19th century), when it was found that the compound is formed from picric acid and phosphorus pentachloride and is converted by boiling with aqueous sodium carbonate solution, again in this, in analogy to the relationship benzoic acid / benzoyl chloride, general carboxylic acid / carboxylic acid chloride.
Representation
It is obtained by nitration of 2,4- dinitrochlorobenzene, but highly concentrated acids (65 % fuming sulfuric acid and 98 % nitric acid ) are required. The compound can also be obtained by the reaction of phosphorus oxychloride with Pyridiniumpikrat.
Properties
Trinitrochlorobenzene forms pale yellow crystalline needles, which melt at 83 ° C. The enthalpy of fusion is 73.3 kJ · kg -1. For the melt vapor pressure data are known.
Trinitrochlorobenzene is a potentially dangerous substance within the meaning of the Explosives Act. Important explosion indicators are:
- Detonation velocity: 7200 m · s-1 at a density of 1.76 g · cm -3
- Deflagration: 395-397 ° C
- Lead block expansion: 31.5 cm3 · g -1
- Impact Sensitivity: 16 N · m
- Friction sensitivity: no reaction to a pin load of 355 N
Reactions
Trinitrochlorobenzene react with many nucleophilic compounds with substitution of the chlorine atom. With aqueous ammonia solution is formed 2,4,6- Trinitroanilin. Hyrazinhydrat provides 2,4,6- Trinitrophenylhydrazin important as an analytical reagent for the detection of ketones and aldehydes.
The Substitionsreaktionen mentioned run by an addition -elimination mechanism. The old comparison with the carboxylic acid chlorides is justified because in both cases a nucleophilic substitution present at the unsaturated carbon atom, which in principle take place via intermediates with tetragonal (sp3 ) carbon atom. In the reaction with alkali metal the Meisenheimer complexes were discovered.
Use
The compound has as an explosive properties similar to trinitrotoluene, this surpasses even explosiveness. However, it is still used in practice little.