Nitrobenzene: Preparation, Properties & Uses.
It is the most of import aromatic nitro compound.
Preparation.
Both inwards the laboratory likewise every bit inwards industry, nitrobenzene is prepared past times heating benzene amongst a mixture of concentrated nitric acid in addition to sulphuric acid at 50°C.
The resulting nitrobenzene is separated, washed amongst sodium carbonate solution to take whatever acid, in addition to purified past times distillation using an air condenser. The laboratory physical care for in addition to the i used on a large scale differ solely inwards working details.
Laboratory Method.
Benzene is added piece of cake to a mixture of concentrated nitric in addition to sulfuric acids inwards a flask. The temperature is kept below 50°C to restrain the formation of m-dinitrobenzene. When the reagents are all mixed, the mixture is heated nether a reflux condenser, amongst shaking for virtually xxx minutes. The contents of the flask are in addition to thence poured into a large sum of H2O to split the nitrobenzene every bit heavy oil. The nitrobenzene
layer is separated from the aqueous Iayer, washed amongst H2O in addition to dilute sodium carbonate solution, dried over anhydrous calcium chloride, in addition to in conclusion distilled (at 207-211°C) using an air condenser.
Commercial Preparation.
On a large scale, nitrobenzene is prepared past times the activity of a mixture of nitric acid in addition to sulphuric acid on benzene. The nitration is carried inwards a stainless steel pan fitted amongst a stirrer in addition to cooling-water pipage to take oestrus generated past times the reaction in addition to to keep the temperature at 50°C. When nitration is complete, the nitrobenzene layer is separated from the spent acid past times decantation. The unsmooth nitrobenzene is in addition to thence washed
with water, sodium carbonate solution, in addition to over again water. The production is in conclusion purified past times distillation inwards a
fractionating column in addition to cooling the vapour inwards air-condenser.
Physical properties.
Nitrobenzene is a pale yellowish liquid (bp 211° C; sp. gr.1.087) having odour of bitter almonds. It is insoluble inwards H2O merely dissolves readily inwards most organic solvents. It is steam- volatile. Nitrobenzene is highly toxic.
Chemical properties.
The chemic reactions of nitrobenzene are those of the nitro grouping in addition to the phenyl group. These convey already been discussed. The solely of import reaction of –NO2 group is that of a reduction inwards acid medium, neutral medium or alkaline metal medium.
Uses.
Nitrobenzene is used.
- for the manufacture of aniline in addition to azo dyestuffs
- as a the high-boiling inert solvent inwards Friedel-Crafts reactions in addition to inwards the depolymerisation of Crepe Rubber for making adhesives.
- as an oxidizing agent inwards Skraup reaction,
- in the training of benzidine in addition to metanilic acid.
Density: 1.2 g/cm³
Molar mass: 123.06 g/mol
Formula: C6H5NO2
Boiling point: 210.9 °C
Melting point: 5.7 °C
ChemSpider ID: 7138
No comments:
Post a Comment