ABC of Safety in the Biological Sciences - Picric Acid

 

ABC of Safety in the Biological Sciences

 


 

PICRIC ACID [(NO2)3C6H2OH]

SYNONYMS
2,4,6­trinitrophenol, picronitric, nitroxanthic acid.
GENERAL PRECAUTIONS
Avoid eye contact.
Avoid skin contact ­ can cause eczema.
Avoid inhalation of the vapour.
Keep away from heat or naked flames.
Keep away from reducing agents and combustible material.
Store the powder under water.
Wash hands thoroughly after handling.
CHARACTERISTICS
Yellow crystals, normally stored under water because of the explosive nature of the crystals when they are dry.
HEALTH HAZARD DATA
A combustible substance that is a contact explosive when the crystals are dry. The powder should be stored under water. It is a strong oxidising agent and reacts violently with combustible material and reducing agents, with fire and explosion hazards. It is toxic and can be absorbed into the body by inhalation (vapour) or ingestion (liquid). It is highly corrosive to eyes. It is an irritant to the skin, eyes and respiratory tract and prolonged exposure to skin may cause dermatitis. It is a neurotoxin and can cause convulsions. It can be absorbed through the skin and discolours the skin, yellow. Inhalation causes sore throat, bronchitis, dry hacking cough and haemoptysis. Ingestion causes abdominal pain, nausea, vomiting and diarrhoea.
TREATMENTS
Skin ­ remove contaminated clothing and immediately wash the affected area with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If irritation or pain persists or eczema develops, seek medical advice. Decontaminate clothing before re-use.
Eyes ­ immediately wash the affected eye with large amounts of water until all evidence of the chemical has been removed (approximately 15 minutes). If irritation or pain persist seek medical advice.
Inhalation ­ remove from the area of exposure to fresh air. Keep warm and allow to rest. Seek immediate medical advice. Ingestion ­ rinse the mouth with water and give plenty of water to drink. Induce vomiting by administering Ipecac syrup. Seek immediate medical attention.
INCOMPATIBILITY
Picric acid is incompatible with:
Combustible material ­ violent reaction.
Oxidising agents - violent reaction.
Reducing substances ­ violent reaction.
Heating produces an explosion risk.
Picric acid reacts with copper, lead and zinc to form compounds that are sensitive to mechanical shock.
Do not allow the powder to dry out ­ explosive.
It has been reported as reacting with calcium salts in concrete to form friction sensitive explosive compounds.
STORAGE
Store the powder under water in a cool, dry atmosphere away from direct sunlight, combustible material and reducing agents and other incompatible substances.
HANDLING
Use a fume hood that will keep the level of exposure below the recommended threshold limit, ie. 0.1 mgm3. If exposure is expected to exceed this limit then a respirator is recommended. Wear protective clothing. A long sleeved laboratory coat or gown, rubber gloves, safety goggles and a face mask as a minimum standard.
DISPOSAL
WEAR:
Butyl rubber gloves, laboratory coat, self contained breathing apparatus and protective shoes.
SPILLS:
On skin and clothing: wash skin with a strong soap solution immediately. Rinse well. Contaminated clothing should be removed and cleaned at once or destroyed by burning.
Small spills: absorb liquid on paper towels or vermiculite; sweep solid spills on to paper. Put on an iron pan in a fume hood and allow to evaporate. Burn the paper or vermiculite in the absence of other inflammables. Wash the site thoroughly with a strong soap solution.
Large spills: absorb or mix with vermiculite, sodium bicarbonate or sand. Package this in a paper carton and burn in an open pit. Use wood scraps and crumpled paper to augment burning. Wash the site thoroughly with a strong soap solution.
PACKAGE LOTS: Either
1 Pour os sift on to sodium bicarbonate or a sand, soda ash mixture (90/10). Mix and package in heavy paper cartons with plenty of paper packing to serve as fuel. Burn in an incinerator.
OR
2 Mix with a flammable solvent and spray into a firebox of an incinerator equipped with an afterburner and scrubber.
NOTE:
Destruction by chemical decomposition is recommended for dinitro, trinitro and other compounds with explosive potential. Add the material, slowly, while stirring, to 30 times its weight of a solution prepared by dissolving 1 part sodium sulphide in 6 parts water. For unstable acidic materials (eg. picric acid) dissolve in 25 times its weight in a solution from 1 part sodium hydroxide and 21 parts sodium sulphide in 200 parts water. Some hydrogen sulphide and ammonia is evolved.
ENVIRONMENT:

 


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