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Butylate (herbicide)

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Butylate
Names
Preferred IUPAC name
S-Ethyl N,N-bis(2-methylpropyl)carbamothioate
Other names
  • Butilate
  • Sutan
  • S-Ethyl diisobutylthiocarbamate
  • S-Ethyl N,N-diisobutylthiocarbamate
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.016.289 Edit this at Wikidata
EC Number
  • 217-916-3
UNII
  • InChI=1S/C11H23NOS/c1-6-14-11(13)12(7-9(2)3)8-10(4)5/h9-10H,6-8H2,1-5H3
    Key: BMTAFVWTTFSTOG-UHFFFAOYSA-N
  • CCSC(=O)N(CC(C)C)CC(C)C
Properties
C11H23NOS
Molar mass 217.37 g·mol−1
Appearance Amber liquid[1]
Odor Aromatic odor[1]
Density 940 kg/m3[2]
Melting point 137.7[2] °C (279.9 °F; 410.8 K)
Boiling point 292.6 °C (558.7 °F; 565.8 K) [3]
45 mg/L[2]
Vapor pressure 170 mPa[2]
Hazards
GHS labelling:
H312, H332[2]
Flash point 115 °C (239 °F; 388 K)
Lethal dose or concentration (LD, LC):
  • 3500 mg/kg (rat, oral)
  • >4640 mg/kg (birds)[2]
>4.2 mg/L (freshwater fish, 96 hours)[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Butylate or butilate is a widely used thiocarbamate herbicide. As a herbicide, it was introduced in 1962,[2] and it quickly became the fourth most used herbicide in the US, with 28.5 million pounds (12.9 thousand tonnes) used in 1974.[4] Its use has declined significantly, to 15 million pounds (6.8 thousand tonnes) in 1991 to 950 thousand pounds (430 tonnes) by 1998. It is used on corn (field, sweet, and popcorn), to control grassy and broadleaf weeds and nutsedge.[5]

Application

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Butylate is applied as an emulsifiable concentrate of 85% active ingredient and is incorporated into the soil, being applied preplant, at plant, postplant, or after harvest. Its maxmimum application rate is 6.3 lb/acre (7.1 kg/Ha), which is much higher than many other herbicides. Soil incorporation is necessary due to the high volatility.[5] Granular and encapsulated forms are also used. Butylate is often used in combination with atrazine and cyanazine.[6]

There is no residential application of butylate; its use is only on feed-crop.[5]

Health

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Butylate is not toxic, not carcinogenic, not teratogenic and not mutagenic.[6] Rat trials show acute neurotoxic effects at the lowest observed adverse effects level (LOAEL) of 2,000 mg/kg/day, leading to a no observed adverse effects level (NOAEL) of 600 milligrams/kilogram/day being established for the general population. At 400 mg/kg/day, rat offspring development was affected, showing decreased fetal weights and increased incidences of misaligned sterebrae,[5] although no developmental effect at any dose is noted in rabbits.[6]

The EPA estimates human food exposure was under 0.3% of the permissible dose for all population subgroups, and so dietary risk of butylate is not a concern.[5][6] Butylate is metabolised rapidly, so there are no residues expected in meat, milk, poultry or eggs, and no intact residues are found in harvested corn.[6]

The EPA requires that pesticide applicators wear, among other items, pants.[6]

Environmental

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Butylate has high volatility, with a vapor pressure of 170 mPa, so it may drift outside of target areas.[2] Butylate is mobile to slightly mobile in soil. Ground water contamination is not expected.[5] Technical butylate is highly toxic to freshwater fish, and non-toxic to birds and mammals. Surface water runoff may occur after rain.[6]

References

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  1. ^ a b "Butylate". pubchem.ncbi.nlm.nih.gov.
  2. ^ a b c d e f g h i Lewis, K.A., Tzilivakis, J., Warner, D. and Green, A. (2016) An international database for pesticide risk assessments and management. Human and Ecological Risk Assessment: An International Journal, 22(4), 1050-1064. DOI: 10.1080/10807039.2015.1133242
  3. ^ "Butylate | C11H23NOS". www.chemspider.com.
  4. ^ "Pesticide Usage Survey of Agricultural, Governmental, and Industrial Sectors in the United States, 1974". epa.gov. EPA. 1977.
  5. ^ a b c d e f "Butylate | Pesticides | US EPA". archive.epa.gov. Retrieved 18 November 2024.
  6. ^ a b c d e f g "Butylate: Reregistration Eligibility Decision (RED) Fact Sheet - US EPA ARCHIVE". archive.epa.gov. EPA. Retrieved 18 November 2024.
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