MCPA

  • 4-Chloro-2-methylphenoxyacetic acid
  • 4-Chloro-o-tolyloxyacetic acid
  • (4-Chloro-2-methylphenoxy)acetic acid
Formula
C9H9ClO3
Structure
Description
Colorless plates.
Uses
Herbicide.

Registry Numbers and Inventories.
CAS
94-74-6
EC (EINECS/ELINCS)
202-360-6
EC Index Number
607-051-00-3
EC Class
Harmful; Irritant
R 22 38 41
S 26 37 39
RTECS
AG1575000
RTECS class
Agricultural Chemical and Pesticide; Tumorigen; Mutagen; Reproductive Effector; Human Data; Primary Irritant
UN (DOT)
2765
Merck
13,5787
Beilstein/Gmelin
2051752
Beilstein Reference
4-06-00-01991
EPA OPP
30501
Swiss Giftliste 1
G-2021
Canada DSL/NDSL
NDSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C9H9ClO3
Formula mass
200.62
Melting point, °C
120
Boiling point, °C
32
Vapor pressure, mmHg
6E-6 (25 C)
Vapor density (air=1)
N/R
Critical temperature
529
Critical pressure
32.4
Density
1.56 g/cm3 (25 C)
Solubility in water
Insoluble
pKa/pKb
3.13 (pKa)
Partition coefficient, pKow
3.25

Hazards and Protection.
Storage
Keep in well ventilated area.
Handling
All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.
Protection
Like 2,4-d self-contained breathing apparatus must be worn. Rubber gloves, hats, suits and boots must be worn.
Respirators
Organic vapor acid gas canister is used.
Small spills/leaks
ELIMINATE all ignition sources. Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS.
Stability
Stable.
Incompatibilities
Reacts as a weak acid to neutralize bases, both organic (for example, the amines) and inorganic Reacts with cyanide salts in the presence of moisture to generate gaseous hydrogen cyanide May react if moist with sulfites, nitrites, thiosulfates (to give H2S and SO3), dithionites (SO2), to generate flammable and/or toxic gases and heat Reacts in this way with all bases, both organic (for example, the amines) and inorganic Can react with active metals to form gaseous hydrogen and a metal salt Flammable and/or toxic gases and heat are generated by the reaction with with diazo compounds, dithiocarbamates, isocyanates, mercaptans, nitrides, and sulfides.
Decomposition
When heated to decomposition it emits toxic fumes of hydrogen chloride and nitrogen oxides.

Fire.
Fire fighting
Self-contained breathing apparatus, rubber gloves, hats, suits and boots must be worn. Highly toxic fumes are imminent.
Fire potential
Nonflammable.
Hazards
When heated, vapors may form explosive mixtures with air: indoors, outdoors, and sewers explosion hazards.
Combustion products
Fire may produce irritating, corrosive and/or toxic gases.

Health.
Poison_Class
4
Exposure effects
Low dose exposures - vertigo, headache, malaise, and paresthesias may occur depending on the specific compound involved. High dose exposures - muscle twitching, spasms, profound weakness, polyneuritis, and unconsciousness may occur depending on the specific compound involved. Idiosyncratic reactions - peripheral neuropathies 2,4-D and 2,4,5-T have caused adverse reproductive effects in experimental animals. Allegations of human birth defects due to these compounds have not been confirmed.
   Ingestion
Nausea, vomiting, and diarrhea have been reported. Necrosis of the gastrointestinal mucosa has been reported.
   Inhalation
Ingestion of large amounts may cause bradypnea, respiratory failure, hyperventilation, or pulmonary edema.
   Skin
Direct contact may cause skin irritation. Chlorodioxin contamination of products may produce chloracne with heavy exposure.
   Eyes
Eye, nose, and mouth irritation are possible with direct contact.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult.
   Skin
Remove and isolate contaminated clothing and shoes. Immediately flush with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin.
   Eyes
Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.

Transport.
UN number
2765
Response guide
Hazard class
6.1