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{{redirect|Tordon|the Swedish ships|HSwMS Tordön}}
'''Picloram''' (C<sub>6</sub>H<sub>3</sub>Cl<sub>3</sub>N<sub>2</sub>O<sub>2</sub>)(Tordon), a picolenic acid herbicide, is the type of herbicide a chemical company loves to sell and those concerned only with killing vegetation love to buy: it is persistent and can be used to kill a large variety of woody plants and annual and perennial broadleaved weeds.
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 472033103
| ImageFile = Picloram.png
| ImageSize = 160
| ImageAlt = Skeletal formula
| ImageFile1 = Picloram-3D-spacefill.png
| ImageSize1 = 160
| ImageAlt1 = Picloram molecule
| PIN = 4-Amino-3,5,6-trichloropyridine-2-carboxylic acid
| OtherNames = Picloram<br>Tordon<br>Grazon
|Section1={{Chembox Identifiers
| PubChem = 15965
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 15170
| InChI = 1/C6H3Cl3N2O2/c7-1-3(10)2(8)5(9)11-4(1)6(12)13/h(H2,10,11)(H,12,13)
| InChIKey = NQQVFXUMIDALNH-UHFFFAOYAR
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C6H3Cl3N2O2/c7-1-3(10)2(8)5(9)11-4(1)6(12)13/h(H2,10,11)(H,12,13)
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = NQQVFXUMIDALNH-UHFFFAOYSA-N
| Abbreviations = ATCP
| CASNo_Ref = {{cascite|correct|CAS}}
| CASNo = 1918-02-1
| UNII_Ref = {{fdacite|changed|FDA}}
| UNII = O7437X49DW
| EINECS =
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 461349
| SMILES = Nc1c(Cl)c(Cl)nc(C(=O)O)c1Cl
| RTECS =
| MeSHName =
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 34922
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C14310
}}
|Section2={{Chembox Properties
| C=6 | H=3 | Cl=3 | N=2 | O=2
| Appearance = colorless to white crystalline solid<ref name=PGCH/>
| Odor = chlorine-like<ref name=PGCH/>
| Density =
| MeltingPtC = 218.5
| MeltingPt_notes = decomposes
| BoilingPt =
| BoilingPt_notes =
| Solubility = 0.04% (20°C)<ref name=PGCH/> 430 mg/L at 25 deg C<ref>{{Cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/picloram#section=Solubility&fullscreen=true |title = Picloram}}</ref>
| VaporPressure = 0.0000006 mmHg (35°C)<ref name=PGCH/>
| SolubleOther =
| Solvent =
| pKa =
| pKb = }}
|Section7={{Chembox Hazards
| MainHazards =
| NFPA-H =
| NFPA-F =
| NFPA-R =
| NFPA-S =
| HPhrases =
| PPhrases =
| GHS_ref =
| FlashPt =
| AutoignitionPt =
| ExploLimits =
| PEL = TWA 15 mg/m<sup>3</sup> (total) TWA 5 mg/m<sup>3</sup> (resp)<ref name=PGCH>{{PGCH|0514}}</ref>
| IDLH = N.D.<ref name=PGCH/>
| REL = none established<ref name=PGCH/>
}}
}}


'''Picloram''' is a systemic herbicide used for general woody plant control. It also controls a wide range of broad-leaved weeds, but most grasses are resistant.<ref name="PMEP">[http://pmep.cce.cornell.edu/profiles/extoxnet/metiram-propoxur/picloram-ext.html Picloram Pesticide Information Profile], Pesticide Management Education Program, [[Cornell University]].</ref> A [[chlorine|chlorinated]] derivative of [[picolinic acid]], picloram is in the [[pyridine]] family of herbicides.
A mixture of picloram and 2,4-D, known as Agent White during the Vietnam War, was sprayed by the US military on those plants that survived the initial onslaught of Agent Orange (2,4,5-T and 2,4-D). That mixture is sold in Australia as Tordon.


Picloram/Tordon can be sprayed on foliage, injected into plants, applied to cut surfaces, or placed at the base of the plant where it will leach to the roots. Once absorbed by the foliage, stem, or roots, picloram is transported throughout the plant, where it is quite stable (ie, just sits there, waiting...).
Picloram can be sprayed on foliage, injected into plants, applied to cut surfaces, or placed at the base of the plant where it will leach to the roots. Once absorbed by the foliage, stem, or roots, picloram is transported throughout the plant.


Herbicides containing picloram are sold under a variety of brand names. [[Dow Chemicals]] and now [[Dow AgroSciences]] sell herbicides containing it under the brand name Tordon.<ref name="Greene2005">{{cite book|author=Stanley A. Greene|title=Sittig's Handbook of Pesticides and Agricultural Chemicals|url=https://books.google.com/books?id=hAoKEHpyu6wC&pg=PA717|year=2005|publisher=William Andrew|isbn=978-0-8155-1903-4|page=717}}</ref>
The very characteristics of Picloram that ensure the killing of a wide variety of plants, however, are also the one ones that cause trouble in the wider environment: persistence, leaching, and broad toxicity to plants in small amounts.


During the [[Vietnam War]], picloram and other herbicides were combined to make [[Agent White]] (commercially available as Tordon 101) and enhanced [[Agent Orange]], which was previously conducted by the British military during the [[Malayan Emergency]]. Large quantities of these herbicides were sprayed by U.S. forces in areas where they considered its long-term persistence desirable, such as inland forests.<ref name="HerbicidesMedicine1994">{{cite book|author1=Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides|author2=Institute of Medicine|title=Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam|url=https://books.google.com/books?id=RjCHcoUE3B8C&pg=PA89|year=1994|publisher=National Academies Press|isbn=978-0-309-55619-4|pages=89–90}}</ref>
==External links==


==Safety==
{{ChemicalSources}}
Picloram is of moderate toxicity to the eyes and only mildly toxic on the skin.<ref name="PMEP"/> No history of human intoxication by picloram has been documented, so symptoms of acute exposure are difficult to characterize.


Picloram is the most persistent of its family of herbicides.<ref>[http://www.epa.gov/safewater/contaminants/dw_contamfs/picloram.html Consumer Factsheet on: PICLORAM], U.S. [[United States Environmental Protection Agency|Environmental Protection Agency]]</ref> It does not adhere to soil, so may leach to groundwater, and has in fact been detected there. It is degraded in soil and water mainly by microbes. Picloram has very little tendency to accumulate in aquatic life.
[[Category:Herbicides]]


Gardeners who use dung as fertilizer should check to make certain that the animal source has not grazed on picloram-treated hay, as the dung still has broadleaf-killing potency.<ref>[http://www.extension.umn.edu/distribution/livestocksystems/M1197.html#3 Use Caution When Harvesting and Feeding Ditch Hay] {{webarchive|url=https://web.archive.org/web/20100614011214/http://www.extension.umn.edu/distribution/livestocksystems/M1197.html |date=2010-06-14 }}, U. Minnesota Extension</ref>
{{organic-compound-stub}}


In regards to occupational exposures, the U. S. [[Occupational Safety and Health Administration]] has established a [[permissible exposure limit]] of 15&nbsp;mg/m<sup>3</sup> total exposure and 5&nbsp;mg/m<sup>3</sup> for respiratory exposure, over an eight-hour workshift.<ref>[https://www.cdc.gov/niosh/npg/npgd0514.html NIOSH Pocket Guide to Chemical Hazards], Centers for Disease Control and Prevention</ref>
[[de:Picloram]]

[[gl:Picloram]]
==References==
[[pl:TORDON]]
<references/>

==External links ==
* {{PPDB|525}}

{{Herbicides}}

[[Category:Auxinic herbicides]]
[[Category:Chloropyridines]]
[[Category:Aminopyridines]]
[[Category:Carboxylic acids]]
[[Category:Herbicides]]

Revision as of 23:55, 22 February 2022

"Tordon" redirects here. For the Swedish ships, see HSwMS Tordön.
Picloram
Skeletal formula
Picloram molecule
Names
Preferred IUPAC name
4-Amino-3,5,6-trichloropyridine-2-carboxylic acid
Other names
Picloram
Tordon
Grazon
Identifiers
3D model (JSmol)
Abbreviations ATCP
ChEBI
ChEMBL
ChemSpider
ECHA InfoCard 100.016.034 Edit this at Wikidata
KEGG
UNII
  • InChI=1S/C6H3Cl3N2O2/c7-1-3(10)2(8)5(9)11-4(1)6(12)13/h(H2,10,11)(H,12,13) checkY
    Key: NQQVFXUMIDALNH-UHFFFAOYSA-N checkY
  • InChI=1/C6H3Cl3N2O2/c7-1-3(10)2(8)5(9)11-4(1)6(12)13/h(H2,10,11)(H,12,13)
    Key: NQQVFXUMIDALNH-UHFFFAOYAR
  • Nc1c(Cl)c(Cl)nc(C(=O)O)c1Cl
Properties
C6H3Cl3N2O2
Molar mass 241.45 g·mol−1
Appearance colorless to white crystalline solid[1]
Odor chlorine-like[1]
Melting point 218.5 °C (425.3 °F; 491.6 K) decomposes
0.04% (20°C)[1] 430 mg/L at 25 deg C[2]
Vapor pressure 0.0000006 mmHg (35°C)[1]
Hazards
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp)[1]
REL (Recommended)
 none established[1]
IDLH (Immediate danger)
 N.D.[1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Picloram is a systemic herbicide used for general woody plant control. It also controls a wide range of broad-leaved weeds, but most grasses are resistant.[3] A chlorinated derivative of picolinic acid, picloram is in the pyridine family of herbicides.

Picloram can be sprayed on foliage, injected into plants, applied to cut surfaces, or placed at the base of the plant where it will leach to the roots. Once absorbed by the foliage, stem, or roots, picloram is transported throughout the plant.

Herbicides containing picloram are sold under a variety of brand names. Dow Chemicals and now Dow AgroSciences sell herbicides containing it under the brand name Tordon.[4]

During the Vietnam War, picloram and other herbicides were combined to make Agent White (commercially available as Tordon 101) and enhanced Agent Orange, which was previously conducted by the British military during the Malayan Emergency. Large quantities of these herbicides were sprayed by U.S. forces in areas where they considered its long-term persistence desirable, such as inland forests.[5]

Safety

Picloram is of moderate toxicity to the eyes and only mildly toxic on the skin.[3] No history of human intoxication by picloram has been documented, so symptoms of acute exposure are difficult to characterize.

Picloram is the most persistent of its family of herbicides.[6] It does not adhere to soil, so may leach to groundwater, and has in fact been detected there. It is degraded in soil and water mainly by microbes. Picloram has very little tendency to accumulate in aquatic life.

Gardeners who use dung as fertilizer should check to make certain that the animal source has not grazed on picloram-treated hay, as the dung still has broadleaf-killing potency.[7]

In regards to occupational exposures, the U. S. Occupational Safety and Health Administration has established a permissible exposure limit of 15 mg/m3 total exposure and 5 mg/m3 for respiratory exposure, over an eight-hour workshift.[8]

References

  1. ^ a b c d e f g NIOSH Pocket Guide to Chemical Hazards. "#0514". National Institute for Occupational Safety and Health (NIOSH).
  2. ^ "Picloram".
  3. ^ a b Picloram Pesticide Information Profile, Pesticide Management Education Program, Cornell University.
  4. ^ Stanley A. Greene (2005). Sittig's Handbook of Pesticides and Agricultural Chemicals. William Andrew. p. 717. ISBN 978-0-8155-1903-4.
  5. ^ Committee to Review the Health Effects in Vietnam Veterans of Exposure to Herbicides; Institute of Medicine (1994). Veterans and Agent Orange: Health Effects of Herbicides Used in Vietnam. National Academies Press. pp. 89–90. ISBN 978-0-309-55619-4.
  6. ^ Consumer Factsheet on: PICLORAM, U.S. Environmental Protection Agency
  7. ^ Use Caution When Harvesting and Feeding Ditch Hay Archived 2010-06-14 at the Wayback Machine, U. Minnesota Extension
  8. ^ NIOSH Pocket Guide to Chemical Hazards, Centers for Disease Control and Prevention
  • Picloram in the Pesticide Properties DataBase (PPDB)
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