Aniline

Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Like most volatile amines, it possesses the somewhat unpleasant odour of rotten fish. It ignites readily, burning with a smoky flame characteristic of aromatic compounds. Aniline is colourless to slightly yellow, but it slowly oxidises and resinifies in air, giving a red-brown tint to aged samples. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1] Aniline does not readily evaporate at room temperature and is slightly soluble in water and mixes readily with most organic solvents. [2]

 

Uses [3,4]

 

Aniline is predominantly used as a chemical intermediate. It is used in rubber accelerators and anti-oxidants, dyes and intermediates, photographic chemicals, as isocyanates for urethane foams, in pharmaceuticals, explosives, petroleum refining; and in production of diphenylamine, phenolics, herbicides and fungicides. Aniline is also used in the manufacture of polyurethanes, rubber processing chemicals, pesticides, fibres, dyes and pigments, photographic chemicals, and pharmaceuticals.

 

Sources & Routes of Exposure [3,4]

 

Sources of Exposure

 

Aniline can be formed from the breakdown of certain pollutants found in outdoor air, from the burning of plastics, or from burning tobacco. Airborne exposure to aniline may occur from breathing contaminated air, from smoking tobacco or proximity to someone who is smoking, or from being near industrial sources that use large quantities of aniline. Occupational exposure to aniline could occur in industries that use aniline to make other chemicals. In addition, small amounts of aniline may be found in some foods, such as corn, grains, rhubarb, apples, beans, and rapeseed cake (animal feed). Aniline has also been found as a volatile component of black tea. Aniline has been detected in drinking water and has also been found in surface water.

 

Routes of Exposure

 

The major routes of exposure for aniline include absorption into the body via inhalation of the vapour, through the skin and by ingestion.

 

Health Effects [3]

 

Acute Effects

 

Acute inhalation exposure to high levels of aniline in humans has resulted in effects on the lung, such as upper respiratory tract irritation and congestion. Aniline has been classified as very toxic in humans, with a probable oral lethal dose in humans at 50 to 500 milligrams per kilogram body weight (mg/kg). It is considered to have high acute toxicity, based on short-term animal tests in rats.

 

Chronic Effects

 

The major effect from chronic inhalation exposure to aniline in humans is the formation of methemoglobin, which can cause cyanosis (interference with the oxygen-carrying capacity of the blood). Aniline is severely irritating to mucous membranes and affects the eyes, skin, and upper respiratory tract in humans. Significant amounts of aniline can be absorbed through the skin. Animal studies have reported a dose-related decrease in red blood cell count, haemoglobin levels, and hematocrit. The Reference Concentration (RfC) for aniline is 0.001 milligrams per cubic meter (mg/m3) based on spleen toxicity in rats.

 

Reproductive/Developmental Effects

 

No information is available on the reproductive or developmental effects of aniline in humans. Birth defects were observed in animals given aniline by gavage (placing the chemical experimentally in the stomachs of the animals). The total number of offspring in mice given aniline by gavage was lower than in the control group even though the average number of offspring per litter was not affected. However, some of the pregnant mice treated with aniline died during pregnancy. Survival of offspring in the aniline-treated group was decreased.

 

Carcinogenicity

 

A study of British workers in the chemical dye industry exposed to aniline and other chemicals concluded that there was insufficient evidence to suggest that aniline itself is a cause of bladder tumours. Animal studies have demonstrated an increase in tumours of the spleen in rats exposed to aniline hydrochloride. EPA considers aniline to be a probable human carcinogen (cancer-causing agent) and has ranked it in EPA’s Group B2.

 

Safety [5]

 

First Aid Measures

 

  • Eye Contact: Check for and remove any contact lenses. Immediately flush eyes with running water for at least 15 minutes, keeping eyelids open. Cold water may be used. Get medical attention. Finish by rinsing thoroughly with running water to avoid a possible infection.
  • 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 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. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. 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: Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. If large quantities of this material are swallowed, call a physician immediately. Loosen tight clothing such as a collar, tie, belt or waistband.

 

Handling & Storage

 

Precautions

 

  • Keep locked up
  • Keep away from heat.
  • Keep away from sources of ignition.
  • Ground all equipment containing material.
  • Do not ingest.
  • Do not breathe gas/fumes/ vapour/spray.
  • 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.
  • Keep away from incompatibles such as oxidising agents, metals, acids, alkalis.

 

Storage

 

  • Aniline is air and light sensitive. Store in light-resistance container.
  • Keep container in a cool, well-ventilated area.
  • Keep container tightly closed and sealed until ready for use.
  • Avoid all possible sources of ignition (spark or flame).

 

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 Protection

 

The following personal protective equipment is recommended when handling aniline:

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

 

Personal Protective Equipment for Large Spills:

  • Splash goggles
  • Full suit
  • Vapour respirator
  • Boots
  • Gloves
  • A self-contained breathing apparatus should be used to avoid inhalation of the product.
  • NOTE: Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.

 

Regulation [4,6]

 

United States

 

OSHA: The Occupational Safety & Health Administration has set the following Permissible Exposure Limits (PEL) for aniline:

  • General Industry: 29 CFR 1910.1000 Z-1 Table — 5 ppm, 19 mg/m3 TWA; Skin
  • Construction Industry: 29 CFR 1926.55 Appendix A — 5 ppm, 19 mg/m3 TWA; Skin
  • Maritime: 29 CFR 1915.1000 Table Z-Shipyards — 5 ppm, 19 mg/m3 TWA; Skin

 

ACGIH: The American Conference of Governmental Industrial Hygienists has set a Threshold Limit Value (TLV)for aniline of 2 ppm, 7.6 mg/m3 TWA; Skin; Appendix A3, Confirmed Animal Carcinogen with Unknown Relevance to Humans; BEI

 

NIOSH: The National Institute for Occupational Safety and Health has listed aniline as a Potential Occupational Carcinogen.

 

Australia

 

Safe Australia: Safe work Australia has set the following exposure limits for aniline:

  • TWA: 2 ppm and 7.6 mg/m3

 

 

References

 

  1. http://en.wikipedia.org/wiki/Aniline
  2. http://www.atsdr.cdc.gov/toxfaqs/tfacts171.pdf
  3. http://www.epa.gov/ttn/atw/hlthef/aniline.html
  4. http://www.npi.gov.au/substances/aniline/index.html
  5. http://www.sciencelab.com/msds.php?msdsId=9927435
  6. https://www.osha.gov/dts/chemicalsampling/data/CH_218800.html

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