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1,1,1-trichloroethane

DESIGNATIONS

CAS No.: 71-55-6
Registry name: 1,1,1-Trichloroethane
Chemical name: Ethane, 1,1,1-trichloro
Synonyms, Trade names: Methyl chloroform, Aerothene, TT, alpha-trichloroethane, Armaclean, Baltane, Champion Fluid, Chlorotene, Chlorothane NU, Chlorothene, Chlorten, Dowclene WR, Drivertan, Escothen, FO 178, Genklene, Inhibisol, K 31, Mecloran, methyltrichloromethane, NCI-CO4626, Solvethane, Telclair X 31, 1,1,1-tri, triethane, Vythene C, Wacker 3X1
Chemical name (German): 1,1,1-Trichlorethan, Methylchloroform
Chemical name (French): Trichloro-1,1,1-thane, chlorethne, mthylchloroforme
Appearance: colourless liquid with sweet, ethereal odour

BASIC CHEMICAL AND PHYSICAL DATA

Empirical formula: C2H3Cl3
Rel. molecular mass: 133.41
Density: 1.338 g/cm3
Relative gas density: 4.55
Boiling point: 74.1C
Melting point: -32.6C
Vapour pressure: 133 hPa at 20C; 200 hPa at 30C; 445 hPa at 50C
Ignition temperature: 537C
Explosion limits: 8.0 - 10.5 vol%
Odour threshold: 100 ppm
Solvolysis/solubility: in water: 1.3 g/l; readily soluble in acetone, benzene, carbon tetrachloride, methanol, diethylether, carbon disulphide
Conversion factors: 1 ppm = 5.54 mg/m3
1 mg/m3 = 0.183 ppm

ORIGIN AND USE

Usage:
According to BGA (1985) about 30% were used as solvents for hot degreasing of metals, 30% for cold degreasing of metals, 30% as solvents in dyes, putties, adhesives, engine cleaners, polishes, lubricants, shrinkdown films, protective coatings, insecticides and aerosols and 10% for miscellaneous purposes such as typewriter corrector fluid. Nowadays, the demand has decreased because of stringent regulations in many industrialised countries. This solvent has been replaced by other products in several applications. Stabilisers are always added to the marketed product. The German Order Governing Working Media (1980) classes 1,1,1-trichloroethane as hazardous to health.

Origin/derivation:
1,1,1-trichloroethane is not a natural product; it is produced industrially from 1,2-dichloroethane or ethane.

Production figures:

USA 1980 314,022 t (ATRI, 1985)
EC 1978 123,000 t (ATRI, 1985)
Japan 1980 86,000 t (ATRI, 1985)
D 1978 35,000 t (DVGW, 1985)
Worldwide 1984 450,000 t (ULLMANN, 1986)

Toxicity

Mammals:
Mouse: LD50 2,568-9,700 mg/kg, oral acc. EPA, 1984
Rat: LD50 10,000 mg/kg (14 d) acc. UBA, 1986
Rat: LD50 11,000-14,300 mg/kg, oral acc. EPA, 1984
Rabbit: LD50 15,800 mg/kg, dermal acc. EPA, 1984
Dog: LD50 4,140 mg/kg, intravenous acc. EPA, 1984
Guinea pig: LD50 8,600 mg/kg, oral acc. EPA, 1984
Aquatic organisms:
Golden orfe: LC0 94 mg/l (48 h) acc. UBA, 1986
Golden orfe: LC50 123 mg/l (48 h) acc. UBA, 1986
Golden orfe: LC100 201 mg/l (48 h) acc. UBA, 1986
American minnow: LC50 52.8-105 mg/l (96 h) acc. UBA, 1986
Blue perch: LC50 69.7 mg/l (96 h) acc. UBA, 1986
Water flea: LC0 2,275 mg/l (24 h) acc. UBA, 1986
Water flea: LC50 530 mg/l (48 h) acc. UBA, 1986
Water flea: LC100 2,384 mg/l (24 h) acc. UBA, 1986
Blue algae: EC3 350 mg/l (7 d, pH=7) acc. UBA, 1986
Green algae: EC3 430 mg/l (7 d, pH=7) acc. UBA, 1986
Invertebrates:
Pseudomonas putida: EC10 > 100 mg/l (30 min) acc. UBA, 1986
Pseudomonas putida: EC3 > 100 mg/l (16 h, pH=7) acc. UBA, 1986
Uronema parduczi: EC5 > 1,040 mg/l (20 h, pH=6.8) acc. UBA, 1986

Characteristic effects:

Humans/mammals: The inhalation of 1,1,1-trichloroethane has a narcotic effect. In contrast to the comparable solvents trichloroethylene ("Tri") and tetrachloroethylene ("Per"), this substance is considerably less toxic. Like other chlorinated hydrocarbons, 1,1,1-trichloroethane may cause severe damages of the liver.

The inhalation of large concentrations causes loss of consciousness, numbness, retarded reaction and respiratory and circulatory paralysis with lethal consequences. The threshold concentration for the occurrence of paralysis in humans is 500 ppm; narcotic effects are observed at 1000 ppm (BGA, 1985). Due to the findings of American studies, 1,1,1-trichloroethane is suspected to cause malignant liver tumours.

In the Federal Republic of Germany, 1,1,1-trichloroethane is listed under pregnancy group C (no hazard of damage to embryos given compliance with MAK and BAT values).

ENVIRONMENTAL BEHAVIOUR

Water:
1,1,1-trichloroethane is heavier than water and thus sinks even in groundwater. It enters the biocycle via the water path. It is ubiquitously detected in surface water; increased concentrations have been observed in recent years in the sea.

Air:
90% of the entire production finally evaporates into the atmosphere and thus participates in the depletion of the ozone layer (DVGW, 1985).

Soil:
1,1,1-trichloroethane accumulates in water-unsaturated soils and in sewage sludge.

Half-life:
The half-life in water-unsaturated soils is more than 2 years. The tropospheric half-life is estimated at 5-10 years (UBA, 1986), with the estimated figure for seawater being 39 weeks, given pH = 8 and 10C (ATRI, 1985).

Degradation, decomposition products:
Degradation in the troposphere - according to ATRI (1985) some 15% of the total amount liberated - finally results by way of phosgene in CO2 and HCl. The reaction with ozone depletes the ozone layer (0.4% by trichloroethane (ATRI, 1985)). Recent investigations have revealed that 1,1,1-trichloroethane may be converted into the toxic 1,2-dichloroethene in the C-horizon (DVGW, 1985).

Food chain:
Roughly 79% of 1,1,1-trichloroethane is absorbed via respiration, 17% by way of foodstuffs and 4% in drinking water.

ENVIRONMENTAL STANDARDS

Medium/
acceptor
Sector Country/ organ. Status Value Cat. Remarks Source
Water: Drinkw D L 0.01 mg/l   1) acc. TVO, 1990
Drinkw EC G 1 g/l   2) acc. DVGW, 1985
Groundw D G 25 g/l   1) acc. UBA, 1986
Air:   D L 90 mg/m3 MIK Short-time value acc. BAUM, 1988
  D L 30 mg/m3 MIK Long-time value acc. BAUM, 1988
Emiss. D L 0.1 g/m3   mass flow > 2 kg/h acc. TA Luft, 1986
Workp D L 1,080 mg/m3 MAK   DFG, 1989
Workp SU (L) 20 mg/m3 PDK   acc. SORBE, 1986
Workp USA L 1,900 mg/m3   Long-time value ACGIH, 1986
Workp USA L 2,450 mg/m3   Short-time value ACGIH, 1986
Foodstuffs:   D L 0.1 mg/kg   3) acc. UMWELT, 1989
  D L 0.2 mg/kg   4) acc. UMWELT, 1989

Notes:

1) Total concentration for 1,1,1-trichloroethane, dichloromethane, trichloroethylene and tetrachloroethylene
2) Sum total of org. chlorine compounds except pesticides
3) 0.1 mg/kg for one of the following substances in each case: tetrachloroethylene, trichloroethane or chloroform
4) As sum total of several solvents within a foodstuff product.

Comparison/reference values

Medium/origin Country

Value

Source
Surface water:
Rhine tributaries, 1978 D

0.1-20 g/l

acc. DVGW, 1985
Rhine: (Lobith, 1978) D

0.01-0.67 g/l

acc. DVGW, 1985
Main: (Kostheim, 1978) D

1.76-2.57 g/l

acc. DVGW, 1985
Lower Main (1980) D

max. 98 g/l

acc. DVGW, 1985
Drinking water:
Ried (1980) D

max. 1.5 g/l

acc. DVGW, 1985
Mannheim (1980) D

max. 2.5 g/l

acc. DVGW, 1985
Japan (5 cities, 1977) J

max. 0.5 g/l

acc. DVGW, 1985
Vienna (1980) A

0.11 g/l

acc. DVGW, 1985
Gothenburg (1978) S

0.06 g/l

acc. DVGW, 1985
Air:
Mean air concentration  

0.1 g/m3

acc. DVGW, 1985
Densely populated areas  

0.5-1 g/m3

acc. DVGW, 1985
Bremen (May-June 1980) D

0.98 g/m3 (n=15)

acc. ATRI, 1985
Bochum (June-Dec. 1978) D

1.8 g/m3

acc. ATRI, 1985
Niagara Falls and Buffalo USA

3,600 ng/m3

acc. ATRI, 1985
Sediment:
Ruhr (1972-1981) D

< 1 g/l

acc. DVGW, 1985
Sewage sludge GB

0.02 mg/kg

acc. ATRI, 1985
Foodstuffs:
Dairy products and fruit D

max. 0.6 g/kg

acc. ATRI, 1985
Olive oil E

10 g/kg

acc. ATRI, 1985
Beef, fat GB

6 g/kg

acc. ATRI, 1985
Potatoes GB

4 g/kg

acc. ATRI, 1985

Assessment/comments

Although 1,1,1-trichloroethane is less toxic than other chlorinated hydrocarbons, the substance cannot be used without restriction. Chronic exposure to low concentrations can cause malignant liver tumours. However, another difference between 1,1,1-trichloroethane and tri- or tetrachloroethylene is its higher stabiliser content which in turn may be harmful. Thus, a substance which is only slightly toxic in its pure form may be highly toxic because of its additives. Residues increasingly accumulate in groundwater as well as in the atmosphere.


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