Description
Carbetamide is pre-and post-emergence carbanilate herbicide. It is highly soluble in water and is relatively volatile. It is moderately toxic to mammals and has a high potential for bioaccumulation. It is a potential carcinogen. Carbetamide has a moderate toxicity to birds, fish, aquatic invertebrates and earthworms. It shows a low toxicity to honeybees, aquatic plants and algae.
Chemical Properties
Carbetamide is a colorless, crystalline powder,
or solid.
Uses
Carbetamide is used in the determination of pesticides.
Definition
ChEBI: A carbamate ester obtained by the formal condensation of phenylcarbamic acid with the hydroxy group of N-ethyl-2-hydroxypropanamide.
Production Methods
Carbetamide is produced commercially through a relatively straightforward chemical synthesis. An aniline derivative is reacted with ethyl chloroformate to form an ethylcarbamoyl intermediate. This intermediate is then coupled with acetic acid derivatives to form the full carbetamide molecule.
Mechanism of action
Selective absorbed by roots with some residual activity. Mitosis inhibitor.
Potential Exposure
Carbamate herbicide used to kill
unwanted plants
Metabolic pathway
Photodegradation of carbetamide in solution with UV
irradiation in the presence of UV H2O2 and TiO2
primarily occurs at the o- and p-positions, but not at
the m-position of the phenyl ring, and the preferential
photoproduct isolated is ortho-hydroxylated
carbetamide. 5-Methyl-3-phenyl-oxazolidine dione is
isolated only in the presence of TiO2. The cyclization
may result from radical coupling with the dissolved
oxygen. N-De-ethylation of the ethylcarbamoyl group
and hydroxylation on the carbamoyloxy linkage occur
to yield free amine of carbetamide and lactamide
analogs. It is interesting to note that formulated
carbetamide is phototransformed to N-ethyllactamide-
4-aminobenzoate as a major product via the
rearrangement reaction similar to the Photo-Fries
reaction. The degradation kinetics of carbetamide and its
potential metabolites are measured at different
temperatures in both unsterilized and sterilized alkaline
soil.
The chemical degradation of carbetamide
importantly gives N-phenyl-3-methyloxazolidine-2,5-
dione which results in 2-(phenylcarbamoyloxy)-
propionic acid and N-phenyl-2-hydroxypropionamide
and the aniline in the soil. The purely biological
degradation of this compound cannot clearly yield
degradation products that are different from those by
chemical degradation in non-sterilized soils.
Shipping
UN2757 Carbamate pesticides, solid, toxic,
Hazard Class: 6.1; Labels: 6.1-Poisonous materials. UN
2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1;
Labels: 6.1-Poisonous materials, Technical Name Required
Incompatibilities
Slowly hydrolyzes in water, releasing
ammonia and forming acetate salts. Carbamates are incompatible with reducing agents, strong acids, oxidizing acids,
peroxides, and bases. Contact with active metals or nitrides
cause the release of flammable, and potentially explosive,
hydrogen gas. Amides react with azo and diazo compounds
to generate toxic gases. Flammable gases are formed by the
reaction of organic amides with strong reducing agents
such as hydrideds and active metals. Amides are very weak
bases (weaker than water). Mixing amides with dehydrating
agents such as phosphorus pentoxide or thionyl chloride
generates the corresponding nitrile. The combustion of
these compounds generates mixed oxides of nitrogen
(NOx). This compound is decomposed by strong base or
acid.
Waste Disposal
Do not discharge into drains
or sewers. Dispose of waste material as hazardous waste
using a licensed disposal contractor to an approved land
fill. Consult with environmental regulatory agencies for
guidance on acceptable disposal practices. Incineration with
effluent gas scrubbing is recommended. Containers must be
disposed of properly by following package label directions
or by contacting your local or federal environmental control
agency, or by contacting your regional EPA office.
