ANILINE
AMINOBENZENE, AMINOPHEN, ARYLAMINE, BENZENAMINE, ANILINE OIL, AND PHENYLAMINE
C6860 Modern Methods of Pollutant Analysis
Chimi Wangmo
454010

INTRODUCTION: BASIC CHARACTERISTICS
¢CAS No: 62-53-3
¢Molecular weight: 93.12 g/mol
¢Molecular formula: C6H5NH2
¢
¢Vapor density:    3.22 (185 °C vs. Air)
¢The vapor pressure:  0.7 mmHg (25 °C)
¢log Kow:    0.90
¢Solubility: 36 mg/mL at 25°C
¢
¢Oily liquid: Colorless to yellowish to brownish with a musty fishy odor
¢

INTRODUCTION: BRIEF HISTORY
¢In 1826 Otto Unverdorben, isolated Aniline from the destructive distillation of indigo: crystallin
¢
¢In 1834, Friedrich Runge isolated from coal tar, a substance that produced a beautiful blue colour
on treatment with chloride of lime- kyanol or cyanol
¢
¢ In 1841, C. J. Fritzsche obtained an oil, by treating indigo with caustic potash- aniline
¢N. N. Zinin found that, on reducing nitrobenzene, a base was formed- benzidam
¢
¢In 1855, August Wilhelm von Hofmann established these variously-prepared substances were identical
- Aniline or phenylamine.

MANUFACTURING PROCESS
¢Catalytic vapor phase reduction of nitrobenzene with hydrogen ¢ reduction of nitrobenzene with
iron filings using hydrochloric acid as catalyst ¢catalytic reaction of chlorobenzene and aqueous
ammonia;
¢ammonolysis of phenol (Japan)

USES
¢Methylene diphenyl diisocyanate (MDI)- used to produce polyurethane foam
¢Rubber accelerators and antioxidants to vulcanise rubber
¢Intermediates for herbicides and pesticides, and dyes and pigments.
¢Minor uses: textile and photographic chemicals, pharmaceuticals, amino resins and explosives.
¢
Use
Percent
MDI(p,p1-methylene diphenyl dissocyanate and polymeric MDI
73-85
Rubber processing Chemicals
18
Pesticides and fibers
9
Pharmaceuticals
2
Dyes and pigments
3
Miscellaneous(agricultural chemicals, specialty resins and photographic chemicals
3

ANILINE PRODUCTION & CONSUMPTION
Region
Consumption
Million tonnes/year
Production
Million tonnes/year
Western Europe
1.32
1.62
USA
1.19
1.38
Eastern Europe
-
0.316
Asia Pacific
0.717
1.15
Japan
0.32
0.474
Latin America
0.073
0.07
Asia/Middle East
0.098
0.064
Source: ICIS Chemical Business
Source: www.ihs.com/products/aniline-chemical-economics-handbook.html
Supply and demand for Aniline in 2006

ENVIRONMENTAL RELEASES
¢Production and processing
—1. Processing to MDI
—<0.013 to 78 ppm to wastewater
—0.014 to 105 ppm to atmosphere
—
—2. Processing to rubber chemicals
—0.44 to 75 ppm to wastewater
—24 to 380 ppm to atmosphere
—
¢as a degradation product of plant protection agents (biotransformation from phenylurea and
carbamate derivatives)
¢microbial reduction of nitrobenzene
¢
¢

ENVIRONMENTAL RELEASES
¢rubber chemicals (degradation product)-tyres abrasion
—In new and used tyres, aniline was detected in concentrations near the detection limit of 100
mg/kg rubber- abrasion
—In distilled water,3.99-86.4 μg aniline/l were detected, while in artificial rain water (pH = 4),
concentrations of 5.91-828 μg/l were found (Baumann and Ismeier, 1997)
¢thermal degradation of polyurethanes – in foundries manufacturing aluminum, Iron, Steel
-occupational risks
—The highest 8-hour TWA of 6.4 mg/m3 exposure level- Swedish study
¢coal and oil industry
—At three shale oil manufacturing sites, aniline concentrations of 0.48 to 5.4 mg/l (Hawthorne and
Sievers, 1984).
¢Landfills
—level of 9.9 μg/l was detected in Canadian landfills
¢

EXPOSURE ROUTES AND HEALTH CONCERNS
¢Inhalation and/or oral uptake- odour can be detected at 1 ppm
¢
¢Aniline vapor is heavier than air and may cause asphyxiation in enclosed, poorly ventilated, or
low-lying areas
¢
¢Aniline is rapidly absorbed from the gastrointestinal tract. Ingestion can lead rapidly to severe
systemic toxicity, nausea and vomiting usually occur
¢
¢Readily absorbed through the skin both from the liquid and gaseous phases
¢

EXPOSURE AND HEALTH EFFECTS
¢Aniline is well absorbed after oral, dermal and inhalation exposure. ¢The extent of absorption
after oral intake amounts 89-96% for rats. The corresponding figures for mice, sheep and pigs are
lower (72%, 80% and 56%, respectively). ¢Dermal absorption in humans was estimated to amount up to
38% ¢Aniline is metabolised to different metabolites by N-acetylation (acetanilide), aromatic
hydroxylation (2- and 4-aminophenol) and N-hydroxylation to N-phenylhydroxylamine which is
responsible for the formation of methaemoglobin
¢ The metabolites are predominantly excreted in the urine.

EXPOSURE AND HEALTH EFFECTS
¢Acute Exposure
¢Many health effects of aniline are due to formation of methemoglobinemia
¢Affects the heart, CNS, kidney, liver, skin, eyes
¢In humans 60 ml of orally administered aniline causes death.
¢0.4-0.6 mg/l air may be borne without much harm for 0.5-1 hour, but 0.1-0.25 mg/l for several
hours produces slight symptoms.
¢Average lethal inhalation dose for humans 0.35-1.43 g/kg body weight.
¢With respect to methaemoglobin formation the no-effect dose of aniline in adult man is about 0.21
mg/kg body weight
¢
¢Chronic exposure
¢Anemia, headaches, tremor, parathesia, pain, narcosis or coma, and cardiac arrhythmia. Heart,
kidney, and liver damage may also occur, possibly as secondary effects of hemolysis
¢
¢Considered a Non Threshold carcinogen :

ECOTOXICOLOGICAL IMPACTS
¢Aniline is deposited in the soil from the atmosphere and via degradation of plant protection
agents.
¢ In soil, aniline will biodegrade and/or bound covalently onto the organic matter. The latter
pathway leads to aniline-humic acid adducts which are immobile and only slowly degraded
¢Aniline found in food such as Rhubarb, black tea
¢
¢Active trees were exposed for 3 hours at a temperature of 25-30°C to aniline
¢At 0.4 ppm, produced as much damage as higher concentrations (up to 10 ppm) - Cheeseman et al.
(1980)
¢
¢In vivo studies shows that aniline causes methemoglobinemia in animals
¢LC50 for dermal absorption in rats: 478 ppm
¢Oral LD50 in rats: 250 mg/kg
¢The LC50/96-hour values for fish -10 and 100 mg/L
¢EC50/ 48-hour values for daphnia - less than 1 mg/L

ENVIRONMENTAL FATE
BIOACCUMULATION
A BCF of 2.6 ± 0.06.. Bioaccumulation potential due to the exposure of the organisms via water is
very low. (Zok et al., 1991).
Degradation rates

ASSESSMENT/MEASUREMENT
¢NIOSH method 2002 (adsorption to silica gel, elution with ethanol, GC-FID)- measurements at
workplace
¢Risk Modeling using EASE software for windows
¢Inhalation exposure:
—In vivo tests
—Measurement of mean Met-Hb in the blood of humans
¢Dermal exposure:
—An investigation of liquid aniline absorption through the skin and urine excretion of the
metabolite 4-aminophenol in man was carried out (Piotrowski, 1957)- gauze test
—Absorption velocity: 0.18 to 0.72 mg/cm2 /h at skin temperatures from 29.8 to 35°C
—Dermal absorption in humans was estimated to amount up to 38%
—

ASSESSMENT/MEASUREMENT
¢Zhu et al., 2004- used GC/MS method to determine aniline and related mono-aromatic amines in
indoor air
—Thermal desorption in place of solvent extraction
—Smoking-source of aniline
—Increased concentration of aniline due to shoe polish: initial indoor air concentration of 0.016
Ag/m3 to 0.53 Ag/m
—
¢Delepee et al., used HPLC/MS/MS for real time monitoring of aniline in fresh water
—Used porous graphitic carbon (PGC) as stationary phase
¢Weiss & Angerer: Used GC/MS –urine samples
—liquid–liquid extraction at pH 6.2–6.4
¢Hanley et al., epidemiological study at a rubber manufacturing plant:
—Company exposure records from 1975–2004 showed a decreasing trend over time, and nearly all
breathing zone TWA measurements were well below published occupational exposure limits, yet bladder
cancer cases were still reported.

MONITORING DATA
¢Aniline is part of a regular monitoring program in the Rhine and its tributaries
¢
¢No atmospheric monitoring data available

REGULATORY STATUS
¢In accordance to the EU criteria for classification and labelling of carcinogens, aniline is
classified as carcinogenic, category 3 and labelled with R 40 “limited evidence of a carcinogenic
effect”.
¢Reference Concentration (RfC) of 1 ug/m3 for aniline in air for the chronic, noncancer effects
(U.S. EPA, 1993)
¢Priority Substances List (PSL1) under the Canadian Environmental Protection Act, 1988 (CEPA 1988).
¢
¢The following occupational exposure limits apply in the EU (ILO, 1994):
¢- DK, S: 4 mg/m3 (1 ml/m3)
¢- FIN, B: 7.6 mg/m3 (2 ml/m3)
¢- D: 8 mg/m3 (2 ml/m3)
¢- UK, F: 10 mg/m3 (2 ml/m3)
¢

REGULATORY STATUS
¢OSHA PEL (permissible exposure limit) = 5 ppm (skin) (averaged over an 8-hour workshift)
¢NIOSH IDLH (immediately dangerous to life or health) = 100 ppm
¢SCOEL
—8-hour TWA: 0.5 ppm [1.94 mg/m3]
—STEL (15 mins): 1.0 ppm [3.87 mg/m3]
—Biological Limit Value (BLV): 30 mg p-aminophenol / litre urine (sampling: 0-2 h after
exposure/shift)
—SCOEL carcinogen group: C (carcinogen with a practical threshold)
—For inhalation aniline exposures at the workplace on the background of cancer risks air
concentrations of 0.2 mg/m3 should not be exceeded
¢High production volume chemical according to European Chemical Substance information system
¢Aniline forming plant protection products come under the Council Directive 91/414/EEC
¢

CONCLUSION
¢Sources of aniline is diverse and its presence in the environment ubiquitous
¢Easily biodegradable in certain conditions, low bio accumulation factor
¢The information available for aniline assessment is from early 2000s. Studies with more precise
methods to quantify aniline especially in manufacturing and processing industries are crucial
¢Cohort studies to ascertain reproductive, carcinogenic, genotoxic effects needs to be under taken
focusing on occupational hazards
¢long term tests with plants, earthworms and micro-organisms to assess risks on soil to be carried
out
¢More rigorous monitoring program to evaluate the effects and releases
¢
¢
¢

REFERENCES
¢Zhu, J. & Aikawa, B. Determination of aniline and related mono-aromatic amines in indoor air in
selected Canadian residences by a modified thermal desorption GC/MS method. Environ. Int. 30,
135–143 (2004).
¢Delépée, R., Chaimbault, P., Antignac, J. P. & Lafosse, M. Validation of a real-time monitoring
method for aniline in freshwater by high-performance liquid chromatography on porous graphitic
carbon/electrospray ionization tandem mass spectrometry. Rapid Commun. Mass Spectrom. 18, 1548–1552
(2004).
¢Hanley, K. W., Viet, S. M., Hein, M. J., Carreón, T. & Ruder, A. M. Exposure to o- Toluidine,
Aniline, and Nitrobenzene in a Rubber Chemical Manufacturing Plant: A Retrospective Exposure
Assessment Update. J. Occup. Environ. Hyg. 9, 478–490 (2012).
¢Assessment, R. European Union Risk Assessment Report. Heal. (San Fr. 77, 107–259
¢