Simazine is an
herbicide
Herbicides (, ), also commonly known as weed killers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page f ...
of the
triazine class. The compound is used to control broad-leaved
weed
A weed is a plant considered undesirable in a particular situation, growing where it conflicts with human preferences, needs, or goals.Harlan, J. R., & deWet, J. M. (1965). Some thoughts about weeds. ''Economic botany'', ''19''(1), 16-24. Pla ...
s and
annual grasses.
Preparation
Simazine may be prepared from
cyanuric chloride and a concentrated solution of
ethyl amine (at least 50 percent by number) in water. The reaction is highly
exothermic
In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity (e ...
and is therefore best carried out below 10 °C.
Cyanuric chloride decomposes at high temperatures into
hydrogen chloride
The Chemical compound, compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colorless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hyd ...
and
hydrogen cyanide
Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...
, both of which are highly toxic by inhalation.
Properties and uses
Simazine is an off-white crystalline compound which is sparingly soluble in water. It is a member of the triazine-derivative herbicides, and was widely used as a residual non-selective herbicide, but is now banned in European Union states.
Like
atrazine
Atrazine ( ) is a Organochlorine compound, chlorinated herbicide of the triazine class. It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn), soybean and sugarcane and on turf, such as golf courses and residential law ...
, a related triazine herbicide, it acts by inhibiting
photosynthesis
Photosynthesis ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...
. It remains active in the soil for two to seven months or longer after application.
See also
*
Atrazine
Atrazine ( ) is a Organochlorine compound, chlorinated herbicide of the triazine class. It is used to prevent pre-emergence broadleaf weeds in crops such as maize (corn), soybean and sugarcane and on turf, such as golf courses and residential law ...
References
External links
Simazine Extoxnet PIP
{{Herbicides
Herbicides
Triazines
Chloroarenes
Group 5 herbicides