Acrylonitrile

2021-12-10

Acrylonitrile is the chemical compound with the formula C3H3N. This pungent-smelling colourless liquid often appears yellow due to impurities. It is an important monomer for the manufacture of useful plastics. In terms of its molecular structure, it consists of a vinyl group linked to a nitrile. [1] Acrylonitrile is soluble in water and most common organic solvents such as acetone, benzene, carbon tetrachloride, ethyl acetate, and toluene. It is a reactive chemical that polymerises spontaneously when heated, or in the presence of a strong alkali, and can explode when exposed to flame. Technical grade acrylonitrile is more than 99% pure and always contains a polymerisation inhibitor, usually methylhydroquinone. It is incompatible and reactive with strong oxidisers, acids and alkalis; bromine; and amines. It attacks copper. [2]

Uses [2]

Acrylonitrile is used in manufacturing acrylic fabrics and carpets. It is used extensively in the manufacture of synthetic fibres, resins, plastics, elastomers, and rubber for a variety of consumer goods such as textiles, dinnerware, food containers, toys, luggage, automotive parts, small appliances, and telephones. It is also used in fumigants. [2]

Acrylonitrile in the Environment [3]

  • Acrylonitrile may be found in the soil, water, or air near industrial sites where it is made, or at hazardous waste sites where it has been disposed of.
  • Because acrylonitrile evaporates easily, most of it is released to the air from facilities where it is produced and used.
  • In air, acrylonitrile breaks down quickly (about half will disappear within 5 to 50 hours) by reacting with other chemicals and sunlight.
  • Acrylonitrile can enter groundwater by filtering through the soil, but it is not commonly found in groundwater.
  • It is broken down by bacteria in surface water.
  • When it is released to soil, some of it will be broken down by bacteria, but most of it will evaporate to the air or filter to groundwater.
  • Acrylonitrile does not build up in the food chain.

Sources of Emission & Routes of Exposure

Sources of Emission [2]

  • Industry sources: The primary stationary sources are likely to be synthetics, paint, and furniture and fixtures manufacturing facilities where this chemical is used.
  • Diffuse sources: Sub-threshold facilities. Acrylonitrile is present in cigarette smoke.
  • Natural sources: Acrylonitrile is not known to occur as a natural product.
  • Transport sources: Acrylonitrile can be found in car exhaust.
  • Consumer products: Acrylonitrile is used as an intermediate in the manufacture of a wide range of consumer products, but undergoes chemical reaction to different substances during the manufacturing process.

Routes of Exposure [3,4]

Exposure routes for acrylonitrile include: inhalation, skin absorption, ingestion, skin and/or eye contact.

Exposure can occur via the following:

  • Breathing contaminated air near hazardous waste sites that contain acrylonitrile.
  • Working in, or living near, industries where it is manufactured or used.
  • Swallowing food and water that contains small amounts of acrylonitrile.

Health Effects [5]

Acute Effects

  • Workers exposed via inhalation to high levels of acrylonitrile for less than an hour experienced mucous membrane irritation, headaches, nausea, feelings of apprehension and nervous irritability; low grade anaemia, leukocytosis, kidney irritation, and mild jaundice were also observed in the workers, with these effects subsiding with the ending of exposure. Symptoms associated with acrylonitrile poisoning include limb weakness, laboured and irregular breathing, dizziness and impaired judgment, cyanosis, nausea, collapse, and convulsions. (1-4)
  • A child died after being exposed to acrylonitrile by inhalation, suffering from respiratory malfunction, lip cyanosis, and tachycardia before death. Several adults exposed to the same concentration of acrylonitrile exhibited eye irritation, but no toxic effects. (1,4)
  • Acute dermal exposure may cause severe burns to the skin in humans. (3)
  • Acute animal tests in rats, mice, rabbits, and guinea pigs have demonstrated acrylonitrile to have high acute toxicity from inhalation and high to extreme acute toxicity from oral or dermal exposure. (5)

Chronic Effects

  • In one study, headaches, fatigue, nausea, and weakness were frequently reported in chronically (long-term) exposed workers.
  • In rats chronically exposed by inhalation, degenerative and inflammatory changes in the respiratory epithelium of the nasal turbinates and effects on brain cells have been observed.
  • The Reference Concentration (RfC) for acrylonitrile is 0.002 milligrams per cubic metre (mg/m3) based on degeneration and inflammation of nasal respiratory epithelium in rats.
  • EPA has calculated a provisional Reference Dose (RfD) of 0.001 milligrams per kilogram body weight per day (mg/kg/d) for acrylonitrile based on decreased sperm counts in mice. The provisional RfD is a value that has had some form of Agency review, but it does not appear on IRIS.

Reproductive/Developmental Effects

  • No information is available on the reproductive or developmental effects of acrylonitrile in humans.
  • Foetal malformations (including short tail, missing vertebrae, short trunk, omphalocele, and hemivertebra) have been reported in rats exposed to acrylonitrile by inhalation.
  • In mice orally exposed to acrylonitrile, degenerative changes in testicular tubules and decreased sperm count were observed.

Cancer Risk

  • A statistically significant increase in the incidence of lung cancer has been reported in several studies of chronically exposed workers. However, some of these studies contain deficiencies such as lack of exposure information, short follow-up, and confounding factors.
  • In several studies, an increased incidence of tumours has been observed in rats exposed by inhalation, drinking water, and gavage. Astrocytomas in the brain and spinal cord and tumours of the Zymbal gland (in the ear canal) have been most frequently reported, as well as tumours of the stomach, tongue, small intestine in males and females, and mammary gland in females.
  • EPA has classified acrylonitrile as a Group B1, probable human carcinogen (cancer-causing agent).
  • EPA uses mathematical models, based on human and animal studies, to estimate the probability of a person developing cancer from breathing air containing a specified concentration of a chemical. EPA calculated an inhalation unit risk estimate of 6.8 × 10-5 (µg/m3)-1.
  • EPA has calculated an oral cancer slope factor of 0.54 (mg/kg/d)-1.

Safety [6]

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. WARM water MUST be used. Get medical attention.
  • Skin Contact: In case of contact, immediately flush skin with plenty of water for at least 15 minutes while removing contaminated clothing and shoes. Cover the irritated skin with an emollient. Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medical attention immediately.
  • Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medical attention.
  • Inhalation: If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention immediately.
  • Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband.
  • WARNING: It may be hazardous to the person providing aid to give mouth-to-mouth resuscitation when the inhaled material is toxic, infectious or corrosive. Seek immediate medical attention.
  • Ingestion: If swallowed, 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 immediately.

Fire & Explosion Information

Acylonitrile is flammable. It has an auto-ignition temperature of 481.11°C (898°F). Its flash points are as follows: Closed Cup = -1.1111°C (30°F) and Open Cup is 0°C (32°F).

Acrylonitrile is highly flammable in presence of open flames and sparks, of heat and slightly flammable-to-flammable in presence of shocks. It is explosive in presence of oxidising materials, acids and alkalis. Dry chemical powder should be used to extinguish small fires and alcohol foam, water spray or fog should be used for large fires. In the presences of catalysts, or when the substance is confined, the polymerisation rate may be accelerated leading to explosion. Acrylonitrile forms explosive mixtures with air based on its low flash point. It easily forms violently explosive polymerides when exposed to heat, light, strong bases, strong acids, strong oxidisers, azoisobuytronitrile, dibenzoyl peroxide, di-tert-butylperoxide, bromine or silver nitrate. Acrylonitrile may explosive reactions with benzyltrimethylammonium hydroxide + pyrrole. It may also have explosive reactions with tetrahydrocarbazole + benzyltrimethylammonium hydroxide.

Exposure Controls & Personal Protection

Engineering Controls

  • Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapours below their respective threshold limit value.
  • Ensure that eyewash stations and safety showers are proximal to the workstation location.

Personal Protective Equipment

The following personal protective equipment is recommended when handling acrylonitrile:

  • Splash goggles;
  • Lab coat;
  • Vapour respirator (be sure to use an approved/certified respirator or equivalent);
  • Gloves

Personal Protection in Case of a Large Spill:

  • Splash goggles;
  • Full suit;
  • Vapour 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.

Regulation

United States [3]

OSHA: The Occupational Safety and Health Administration has set a limit of 2 ppm over an 8-hour workday, 40-hour workweek.

NIOSH: The National Institute of Occupational Safety and Health (NIOSH) recommends that average workplace air should not exceed 1 part per million (1 ppm) acrylonitrile averaged over a 10-hour period.

EPA: The Environmental Protection Agency recommends that levels in lakes and streams should be limited to 0.058 parts of acrylonitrile per billion parts of water (0.058 ppb) to prevent possible health effects from drinking water or eating fish contaminated with acrylonitrile. Any release to the environment greater than 100 pounds of acrylonitrile must be reported to the EPA.

Australia [2]

Safe Work Australia: Safe Work Australia recommends an 8-hour time weighted average (TWA) exposure limit of 2 ppm (4.3 mg/m3)

References

http://en.wikipedia.org/wiki/Acrylonitrile

http://www.npi.gov.au/resource/acrylonitrile-2-propenenitrile

http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=446&tid=78

http://www.cdc.gov/niosh/npg/npgd0014.html

http://www.epa.gov/ttn/atw/hlthef/acryloni.html

http://www.sciencelab.com/msds.php?msdsId=9922795