samedi 19 janvier 2013

Ammonium nitrate chemical data and thermodynamic properties

The ammonium nitrate formula is NH4NO3. It is obtained by chemical reaction between nitric acid and ammonia : NH3 + HNO3 ------> NH4NO3
The discovery of ammonium nitrate is thanks to Hans Rudolf Glauber. It was in 1659. Nowadays, ammonium nitrate is used in agriculture as nitrogenous fertilizer. But it is used also as a component of civil or millitary explosive.
Chemical properties :
Formula                                           NH4NO3
Molecular weight                            80.05 g/mol
Density                                            1.725
Specific heat (0 °C - 31 °C)            1.7 J/g.K                     
Melting point                                  169 °C
PH (aqueous solution 0.1 M)          5.43 
Thermodynamic data :
 Enthalpy of formation of ammonium nitrate : 
N2(g) + 2H2 + 3/2 O2(l) ----------> NH4NO3 (s)                ΔH°f = 366 kJ/mol

Enthalpy of reaction of ammonium nitrate : 
NH3 (g) + HNO3 (l) -------------> NH4NO3 (s)                  ΔH°r = 146 kJ/mol

NH3 (l) + HNO3 (l) -------------> NH4NO3 (s)                  ΔH°r = 172 kJ/mol

 Enthalpy of decomposition of ammonium nitrate :
 NH4NO3 (s) ---------> 2H2O + N2 + 1/2 O2                    ΔHd = -118.04 kJ/mol

  Enthalpy of dilution of ammonium nitrate :
The ammonium nitrate dilution in water is endothermic processus. The heat of dilution in infinite solution is about 63 kcal/mol.

Ammonium Nitrate Material Safety Data Sheet 3/3

Exposure Controls/Personal Protection:
Engineering Controls: Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits. If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit.
Personal Protection: Splash goggles. Lab coat. Dust respirator. Be sure to use an approved/certified respirator or equivalent.
Personal Protection in Case of a Large Spill: Splash goggles. Full suit. Dust respirator. Boots. Gloves. A self contained breathing apparatus should be used to avoid inhalation of the product. Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.
Stability and Reactivity Data:
Stability: The product is stable under atmospheric conditions (temperature and pressure)
Conditions of Instability: Incompatible materials or high teperature
Incompatibility with various substances: Reactive with reducing agents, combustible materials, organic materials, metals, alkalis.
Special Remarks on Reactivity: Also incompatible with finely powdered metals (aluminum, copper, chromium, iron, zinc brass, nickel , lead, manganese, magnesium, antimony), acetic acid, ammonium chloride, phosphorus, sodium perchlorate, sulfur, bismuth, cadmium, chlorides, cobalt, potassium and ammonium sulfate, sodium, sodium hypochlorite, sodium-potassium alloy, organic materials and combustible materials (paper, oil, charcoal, etc.)

Toxicological Information:
Routes of Entry: Absorbed through skin. Inhalation. Ingestion.
Toxicity to Animals: Acute oral toxicity (LD50): 2217 mg/kg [Rat].
Chronic Effects on Humans: Causes damage to the following organs: lungs, mucous membranes. May cause damage to the following organs: blood, gastrointestinal tract.
Other Toxic Effects on Humans: Hazardous in case of skin contact (irritant), of ingestion, of inhalation (lung irritant). Slightly hazardous in case of skin contact (permeator).
Special Remarks on Chronic Effects on Humans: Carcinogenic effects: At this time, no studies were found on the possible carcinogenicity of Ammonium Nitrate in humans or experimental animals. However nitrates can be reduced to nitrites in the body, and the formed nitrites can subsequently react with amines to form suspect carcinogens N-nitrosamines. Genetic Effects: No genetic data was found for ammonium. However, in general, nitrates and nitrites are genotoxic. Reproductive Effects: There has been some association between consumption of nitrate-contaminated well water and birth defects, especially neural tube defects. However, these studies would not specifically implicate Ammonium Nitrate.
Special Remarks on other Toxic Effects on Humans: Acute Potential Health Effects: Skin: Causes skin irritation. It may be absorbed through intact skin. Eyes: Causes eye irritation.
Inhalation: Causes respiratory tract (nose, throat), and mucous membrane irritation. Symptoms may include: coughing, severe lung congestion, difficulty breathing. Inhalation of large amounts may cause systemic acidosis, Methemoglobinemia with symptoms similar to acute ingestion. Ingestion: Gastroenteritis with abdominal pain, nausea, vomiting, diarrhea. Exposure to large amounts may affect behavior/central nervous system, and blood and cause Methemoglobinemia, and systemic acidosis. Symptoms of Methemoglobinemia include cyanosis (blue lips, eyelids, earlobes, and skin), headache, fatigue, weakness, convulsions, dizziness, loss of coordination, nausea, vomiting, dyspnea, and drowsiness. It may also affect the cardiovascular system and cause increased or decreased heart rate, and hypotension. Chronic Potential Health Effects: Ingestion: The toxicity of nitrates is due to in vivo conversion to nitrites. Chronic ingestion of more than 5 mg/kg/day is considered unacceptable. Primary overdose effects include orthostatic hypotension and Methemoglobinemia. Orthostatic hypotension, faintness, fatigue, weakness, depression, mental impairment, dizziness, shortness of breath, and reflex tachycardia are common; headache, nausea and vomiting may also occur. Chronic ingestion may also cause nephritis.

Ammonium Nitrate Material Safety Data Sheet 2/3

Fire and Explosion Data:
Flammability of the Product: May be combustible at high temperature.
Auto-Ignition Temperature: 300°C (572°F)
Flash Points: CLOSED CUP: Higher than 93.3°C (200°F).
Fire Hazards in Presence of Various Substances: Slightly flammable to flammable in presence of heat, of combustible materials, of organic materials. Non-flammable in presence of shocks.
Explosion Hazards in Presence of Various Substances: Risks of explosion of the product in presence of mechanical impact: Not available. Risks of explosion of the product in presence of static discharge: Not available. Slightly explosive in presence of heat, of combustible materials, of organic materials, of metals.
Fire Fighting Media and Instructions: Oxidizing material. Do not use water jet. Use flooding quantities of water. Avoid contact with organic materials.
Special Remarks on Fire Hazards: Caution: Strong Oxidizer. Contact with material may cause a fire. Contact with combustible or organic materials may cause fire.
Special Remarks on Explosion Hazards: It is an oxidizing agent and can self-ignite/detonate when in contact with powdered metals and some organic materials such as Urea and Acetic Acid.

Accidental Release Measures
Small Spill: Use appropriate tools to put the spilled solid in a convenient waste disposal container.
Large Spill: Oxidizing material. Stop leak if without risk. Avoid contact with a combustible material (wood, paper, oil, clothing...). Keep substance damp using water spray. Do not touch spilled material. Prevent entry into sewers, basements or confined areas; dike if needed. Eliminate all ignition sources. Call for assistance on disposal.
Handling and Storage:
Precautions: Keep away from heat. Keep away from sources of ignition. Keep away from combustible material. Do not ingest. Do not breathe dust. Wear suitable protective clothing. In case of insufficient ventilation, wear suitable respiratory equipment. If ingested, seek medical advice immediately and show the container or the label. Avoid contact with skin and eyes.
Storage: Keep container tightly closed. Keep container in a cool, well-ventilated area. Separate from acids, alkalies, reducing agents and combustibles. See NFPA 43A, Code for the Storage of Liquid and Solid Oxidizers.

Ammonium Nitrate Material Safety Data Sheet 1/3

Chemical Name: Ammonium Nitrate
Chemical Formula: NH4NO3
Hazards Identification :
Potential Acute Health Effects: Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion, of inhalation (lung irritant). Slightly hazardous in case of skin contact (permeator). Prolonged exposure may result in skin burns and ulcerations. Over-exposure by inhalation may cause respiratory irritation.
Potential Chronic Health Effects: 
The substance is toxic to lungs, mucous membranes. The substance may be toxic to blood, gastrointestinal tract. Repeated or prolonged exposure to the substance can produce target organs damage.
First Aid Measures :
Eye Contact: Check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Cold water may be used. Get medical attention.
Skin Contact: In case of contact, immediately flush skin with plenty of water. Cover the irritated skin with an emollient. Remove contaminated clothing and shoes. Cold water may be used.Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medical attention.
Serious Skin Contact:
Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek medical attention.
Inhalation: If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention.
Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek medical attention.
Ingestion: Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention if symptoms appear.


jeudi 17 janvier 2013

What is ammonium nitrate ?


It is a white crystalline solid at room temperature and standard pressure. It is used in agriculture as a nitrogen fertilizer and also in explosives as oxidizing agent.


Chemical formula : NH4NO3