2,4,5-Trichlorophenoxyacetic acid Property

Melting point:

154-158 °C(lit.)

Boiling point:

361.82°C (rough estimate)

Density 

1.6048 (rough estimate)

vapor pressure 

6.46 at 25 °C (Lewis, 1989)

refractive index 

1.4700 (estimate)

Flash point:

2 °C

storage temp. 

0-6°C

solubility 

Soluble in ethanol (548.2 mg/L), ether (243.2 mg/L), heptane (400 mg/L), xylenes (6.8 g/L), methanol (496 g/L), toluene (7.32 g/L) (quoted, Keith and Walters, 1992).

form 

crystalline

pka

2.80 and 2.83 at 25 °C (ionic strength <0.01 M, Jafvert et al., 1990)
2.88 (Nelson and Faust, 1969)

color 

off-white to yellow

Water Solubility 

238mg/L(20 ºC)

Merck 

13,9111

Henry's Law Constant

4.87 at 25 °C (approximate - calculated from water solubility and vapor pressure)

Exposure limits

NIOSH REL: TWA 10 mg/m3, IDLH 250 mg/m3; OSHA PEL: TWA 10 mg/m3; ACGIH TLV: TWA 10 mg/m3.

Stability:

Stable. Incompatible with strong bases, strong oxidizing agents, alkali metals, amines, alcohols. Reacts with many common metals.

CAS DataBase Reference

93-76-5(CAS DataBase Reference)

NIST Chemistry Reference

Acetic acid, 2,4,5-trichlorophenoxy-(93-76-5)

EPA Substance Registry System

2,4,5-T (93-76-5)

Safety

Hazard Codes 

Xn,N,F

Risk Statements 

22-36/37/38-50/53-36-20/21/22-11

Safety Statements 

24-60-61-36/37-26-16

RIDADR 

UN 2811 6.1/PG 3

WGK Germany 

3

RTECS 

AJ8400000

HazardClass 

6.1(b)

PackingGroup 

III

HS Code 

29189100

Hazardous Substances Data

93-76-5(Hazardous Substances Data)

Toxicity

LC50 (96-hour) for rainbow trout 350 mg/L and carp 355 mg/L (Hartley and Kidd, 1987); acute oral LD50 for rats 500 mg/kg (Hartley and Kidd, 1987), 300 mg/kg (RTECS, 1985).

IDLA

250 mg/m3

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H301Toxic if swalloed

H312Harmful in contact with skin

H315Causes skin irritation

H319Causes serious eye irritation

H335May cause respiratory irritation

H410Very toxic to aquatic life with long lasting effects

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P273Avoid release to the environment.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P301+P310IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

2,4,5-Trichlorophenoxyacetic acid Chemical Properties,Usage,Production

Chemical Properties

white to light tan odourless solid

Chemical Properties

2,4,5-T Acid is an odorless, colorless to tan crystalline solid.

Physical properties

Colorless to pale brown, odorless crystals. Odor threshold from water is 2.92 mg/kg (quoted, Keith and Walters, 1992). Metallic taste.

Uses

2,4,5-T was formerly used as a herbicide. Itis currently not used, following a ban by theEPA.

Uses

Plant hormone; defoliant; herbicide used to control undesirable brush and woody plants.

Uses

It is suitable for plant cell culture tested. Post-emergence herbicide.

Definition

ChEBI: A chlorophenoxyacetic acid that is phenoxyacetic acid in which the ring hydrogens at postions 2, 4 and 5 are substituted by chlorines.

General Description

Light tan solid (melting point 153°C). Insoluble in water. Contact may irritate the skin.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

2,4,5-Trichlorophenoxyacetic acid is a weak acid. Reacts with organic and inorganic bases to form water-soluble salts and with alcohols to form esters. Incompatible with strong oxidizing agents and strong bases. Can corrode metals, especially if moist. May harm painted surfaces .

Health Hazard

Overexposure to dust by inhalation or ingestion may cause fatigue, nausea, vomiting, lowered blood pressure, convulsions, coma. Dust may irritate eyes and skin.

Health Hazard

The toxicity of 2,4,5-T is very similar tothat of 2,4-D. The symptoms are irritationof skin, acne-like rash, somnolence, gastritis,fatty liver degeneration, and ataxia.
LD50 value, oral (rats): 300 mg/kg
Oral administration of this compound inhamsters and mice produced fetotoxicity,as well as developmental toxic effects onthe central nervous system, eyes, ear, andprostate.

Fire Hazard

Special Hazards of Combustion Products: Toxic hydrogen chloride and phosgene gases may be formed.

Potential Exposure

Those engaged in the manufacture, formulation, and application of this herbicide used to control woody and herbaceous weeds. The EPA has issued a rebuttable presumption against registration of 2,4,5-T for pesticide uses, however. The Viet Nam war era defoliant, Agent Orange, was a mixture of 2,4,5-T and 2,4-D.

Carcinogenicity

2,4,5-T was not mutagenic in bacterial assays, and it did not induce aneuploidy or somatic mutation in vitro. In vivo it did not cause micronuclei in mice or dominant lethal mutations in mice or rats.

Environmental Fate

Biological. 2,4,5-T degraded in anaerobic sludge by reductive dechlorination to 2,4,5- trichlorophenol, 3,4-dichlorophenol and 4-chlorophenol (Mikesell and Boyd, 1985). An anaerobic methanogenic consortium, growing on 3-chlorobenzoate, metabolized 2,4,5-T to (2,5-dichlorophenoxy)acetic acid at a rate of 1.02 × 10–7 M/hr. The half-life was reported to be 2 days at 37°C (Su?ita et al., 1984). Under aerobic conditions, 2,4,5-T degraded to 2,4,5- trichlorophenol and 3,5-dichlorocatechol which may further degrade to 4-chlorocatechol or cis,cis-2,4-dichloromuconic acid, 2-chloro-4-carboxymethylenebut-2-enolide, chlorosuccinic acid and succinic acid (Byast and Hance, 1975). The cometabolic oxidation of 2,4,5-T by Brevibacterium sp. yielded a product tentatively identified as 3,5-dichlorocatechol (Horvath, 1970). The cometabolism of this compound by Achromobacter sp. gave 3,5-dichloro-2- hydroxymuconic semialdehyde (Horvath, 1970a). Rosenberg and Alexander (1980) reported that 2,4,5-trichlorophenol, the principal degradation product of 2,4,5-T by microbes, was further metabolized to 3,5-dichlorocatechol, 4-chlorocatechol, succinate, cis,cis-2,4-dichlo- romuconate, 2-chloro-4-(carboxymethylene)but-2-enolide and chlorosuccinate.
Soil. 2,4,5-Trichlorophenol and 2,4,5-trichloroanisole were the primary degradation products formed when 2,4,5-T was incubated in soil at 25°C under aerobic conditions. The half-life under these conditions was 14 days (McCall et al., 1981a). When
The half-lives of 2,4,5-T in soil incubated in the laboratory under aerobic conditions ranged from 14 to 64 days with an average of 33 days (Altom and Stritzke, 1973; Foster and McKercher, 1973; Yoshida and Castro, 1975). In field soils, the disappearance
Groundwater . According to the U.S. EPA (1986) 2,4,5-T has a high potential to leach to groundwater .
Photolytic. When 2,4,5-T (10–4 M) in oxygenated water containing titanium dioxide (2 g/L) suspension was irradiated by sunlight (λ ≥340 nm), 2,4,5-trichlorophenol, 2,4,5- trichlorophenyl formate and nine chlorinated aromatic hydrocarbons formed a

Solubility in water

Soluble in ethanol (548.2 mg/L), ether (243.2 mg/L), heptane (400 mg/L), xylenes (6.8 g/L), methanol (496 g/L), toluene (7.32 g/L) (quoted, Keith and Walters, 1992).

Shipping

UN2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required. UN3345 Phenoxyacetic acid derivative pesticide, solid, toxic, Hazard Class: 6.1; Labels: 6.1-Poisonous materials.

Purification Methods

Crystallise this herbicide from *benzene. [Beilstein 6 III 721.] (CANCER SUSPECT)

Incompatibilities

The aqueous solution is a weak acid. Incompatible with sulfuric acid, bases, ammonia, aliphatic amines; alkanolamines, isocyanates, alkylene oxides; epichlorohydrin; strong oxidizers, such as chlorine, bromine, fluorine, and strong bases.

Waste Disposal

Two disposal procedures have been discussed for 2,4,5-T: (1) Mix with excesssodium carbonate, add water and let stand for 24 hours before flushing down the drain with excess water; and (2) pour onto vermiculite and incinerate with wood, paper, and waste alcohol. In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed properly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal.