6PPD

6PPD is an organic chemical that is widely used as an antiozonant and antioxidant in rubber tires.[1] It is one of several p-phenylenediamine (PPD) additives used to protect various rubber materials.[2]

6PPD
Names
Preferred IUPAC name
N1-(4-Methylpentan-2-yl)-N4-phenylbenzene-1,4-diamine
Other names
N-(1,3-dimethylbutyl)-N'-phenyl-1,4-benzenediamine
  • N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine
  • 6PPD
  • DMBPPD
Identifiers
3D model (JSmol)
ChEMBL
ChemSpider
ECHA InfoCard 100.011.222
EC Number
  • 212-344-0
UNII
UN number 3077
  • InChI=1S/C18H24N2/c1-14(2)13-15(3)19-17-9-11-18(12-10-17)20-16-7-5-4-6-8-16/h4-12,14-15,19-20H,13H2,1-3H3
    Key: ZZMVLMVFYMGSMY-UHFFFAOYSA-N
  • CC(C)CC(C)NC1=CC=C(C=C1)NC2=CC=CC=C2
Properties
C18H24N2
Molar mass 268.404 g·mol−1
Appearance brown or violet solid powder
Density 1.07
Melting point 45 °C (113 °F; 318 K)
Boiling point 260 °C (500 °F; 533 K)
log P 3.972
Hazards
GHS labelling:
Danger
H302, H317, H360, H410
P201, P202, P261, P264, P270, P272, P273, P280, P281, P301+P312, P302+P352, P308+P313, P321, P330, P333+P313, P363, P391, P405, P501
Flash point 204 °C (399 °F; 477 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Manufacturing

6PPD is prepared by reductive amination of methyl isobutyl ketone with 4-aminodiphenylamine.[3]

Environmental Impact

The formation of a quinone-form of 6PPD (6PPD-Q) is the intended function of this rubber additive. But a 2020 study found that 6PPD (or already converted 6PPD-Q) released from vehicle tires gets converted by ozone to a previously unknown quinone analog 6PPD-quinone:

and that 6PPD-quinone is the toxic chemical in storm water runoff responsible for killing coho salmon before they spawn in freshwater streams.[4][5][6]

A 2022 study also identified the toxic impact on species like brook trout and rainbow trout.[7] The published lethal concentrations are:[7] [8]


A synthetic route to the 6PPD-quinone has been posted on ChemRxiv.[9]

See also

References
  1. U.S. Tire Manufacturers Association (July 15, 2021). "Statement of Sarah E. Amick Vice President EHS&S and Senior Counsel U.S. Tire Manufacturers Association". Committee on Natural Resources Subcommittee on Oversight and Investigations United States House of Representatives.
  2. Krüger, R H; Boissiére, C; Klein-Hartwig, K; Kretzschmar, H-J (2005). "New phenylenediamine antiozonants for commodities based on natural and synthetic rubber". Food Addit Contam. 22 (10): 968–974. doi:10.1080/02652030500098177. PMID 16227180. S2CID 10548886.
  3. Hans-Wilhelm Engels et al., "Rubber, 4. Chemicals and Additives" in Ullmann's Encyclopedia of Industrial Chemistry, 2007, Wiley-VCH, Weinheim. doi:10.1002/14356007.a23_365.pub2
  4. Tian, Zhenyu; Zhao, Haoqi; Peter, Katherine T.; Gonzalez, Melissa; Wetzel, Jill; Wu, Christopher; Hu, Ximin; Prat, Jasmine; Mudrock, Emma; Hettinger, Rachel; Cortina, Allan E.; Biswas, Rajshree Ghosh; Kock, Flávio Vinicius Crizóstomo; Soong, Ronald; Jenne, Amy; Du, Bowen; Hou, Fan; He, Huan; Lundeen, Rachel; Gilbreath, Alicia; Sutton, Rebecca; Scholz, Nathaniel L.; Davis, Jay W.; Dodd, Michael C.; Simpson, Andre; McIntyre, Jenifer K. (3 December 2020), "A ubiquitous tire rubber–derived chemical induces acute mortality in coho salmon", Science, 371 (6525): 185–189, doi:10.1126/science.abd6951, PMID 33273063, S2CID 227281491, ... existing TWP [tire wear particle] loading, leaching, and toxicity assessments are clearly incomplete. ... Accordingly, the human health effects of such exposures merit evaluation. ... It is unlikely that coho salmon are uniquely sensitive ...
  5. "Pollution from car tires is killing off salmon on US west coast, study finds". The Guardian. 3 December 2020.
  6. "Scientists solve mystery of mass coho salmon deaths. The killer? A chemical from car tires". Los Angeles Times. 3 December 2020.
  7. Markus Brinkmann, David Montgomery, Summer Selinger, Justin G. P. Miller, Eric Stock (2022-03-02), "Acute Toxicity of the Tire Rubber-Derived Chemical 6PPD-quinone to Four Fishes of Commercial, Cultural, and Ecological Importance", Environmental Science & Technology Letters, doi:10.1021/acs.estlett.2c00050{{citation}}: CS1 maint: multiple names: authors list (link)
  8. Tian, Zhenyu; Gonzalez, Melissa; Rideout, Craig; Zhao, Hoaqi Nina; Hu, Ximin; Wetzel, Jill; Mudrock, Emma; James, C. Andrew; McIntyre, Jenifer K; Kolodziej, Edward P (11 January 2022), "6PPD-Quinone: Revised Toxicity Assessment and Quantification with a Commercial Standard", Environmental Science & Technology Letters, doi:10.1021/acs.estlett.1c00910
  9. Agua, Alon; Stanton, Ryan; Pirrung, Michael (2021-02-04). "Preparation of 2-((4-Methylpentan-2-Yl)amino)-5-(Phenylamino)cyclohexa-2,5-Diene-1,4-Dione (6PPD-Quinone), an Environmental Hazard for Salmon". ChemRxiv. doi:10.26434/chemrxiv.13698985.v1.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.