1,2,3-Trichloropropane

1,2,3-Trichloropropane (TCP) is an organic compound with the formula CHCl(CH2Cl)2. It is a colorless liquid that is used as a solvent and in other specialty applications.[3]

1,2,3-Trichloropropane
Names
Preferred IUPAC name
1,2,3-Trichloropropane
Other names
TCP
Allyl trichloride
Glycerol trichlorohydrin
Trichlorohydrin
Identifiers
3D model (JSmol)
Abbreviations TCP
ChEMBL
ChemSpider
ECHA InfoCard 100.002.261
EC Number
  • 202-486-1
KEGG
UNII
Properties
C
3H
5Cl
3
Molar mass 147.43 g
Appearance colorless or straw yellow transparent liquid
Odor chloroform-like[1]
Density 1.387g/mL
Melting point −14 °C (7 °F; 259 K)
Boiling point 156.85 °C (314.33 °F; 430.00 K)
1,750 mg/L
log P 2.27
Vapor pressure 3 mmHg (20°C)[1]
4.087 x 10−4
Hazards
Flash point 71 °C; 160 °F; 344 K [1]
Explosive limits 3.2%-12.6%[1]
Lethal dose or concentration (LD, LC):
555 ppm (mouse, 2 hr)[2]
5000 ppm (mouse, 20 min)[2]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 50 ppm (300 mg/m3)[1]
REL (Recommended)
 Ca TWA 10 ppm (60 mg/m3) [skin][1]
IDLH (Immediate danger)
 Ca [100 ppm][1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Production

1,2,3-Trichloropropane is produced the addition of chlorine to allyl chloride.[3] TCP also may be produced as a byproduct also is produced in significant quantities as an unwanted by-product of the production of other chlorinated compounds such as epichlorohydrin and dichloropropene.[4][5]

Uses

Historically, TCP has been used as a paint or varnish remover, a cleaning and degreasing agent, and an solvent.[3] It is also used as an intermediate in the production of hexafluoropropylene.[6] It is a crosslinking agent for polysulfide polymers and sealants.

Effects of exposure

Humans can be exposed to TCP by inhaling its fumes or through skin contact and ingestion. TCP is recognized in California as a human carcinogen, and extensive animal studies have shown that it causes cancer. Short term exposure to TCP can cause throat and eye irritation and can affect muscle coordination and concentration. Long term exposure can affect body weight and kidney function.[6]

Regulation

United States

Proposed federal regulation

As of 2013 TCP was not regulated as a contaminant by the federal government, but research shows that it could have severe health effects; only the state of California had significant regulation of this compound.

In a drinking water project proposed by the United States Environmental Protection Agency (EPA), TCP was one of sixteen suspected human carcinogens being considered for regulation in 2011.[7]

State regulation

Pre-1980s, agricultural use of chloropropane-containing soil fumigants for use as pesticides and nematicides was prevalent in the United States. Some soil fumigants, which contained a mixture of primarily 1,3-dichloropropene and 1,2-dichloropropane, and in which 1,2,3-TCP was a minor component, e.g., trade name of D-D, were marketed for the cultivation of various crops including citrus fruits, pineapples, soy beans, cotton, tomatoes, and potatoes. D-D was first marketed in 1943, but is no longer available in the United States, and has been replaced with Telone II, which was first available in 1956. Telone II reportedly contains as much as 99 percent 1,3-dichloropropene and up to 0.17 percent by weight 1,2,3-TCP (Zebarth et al., 1998). Before 1978, approximately 55 million pounds/year of 1,3-dichloropropene were produced annually in the United States, and approximately 20 million pounds/year of 1,2-dichloropropane and 1,2,3-TCP were produced as by-products in the production of 1,3-dichloropropene. Over 2 million pounds of pesticides containing 1,3-dichloropropene were used in California alone in 1978. Telone II is still used for vegetables, field crops, fruit and nut trees, grapes, nursery crops, and cotton.

The California State Water Resources Control Board's Division of Drinking Water established an enforceable Maximum Contaminant Level (MCL) of 5 ng/L (parts per trillion).[8] The state of Alaska has promulgated standards establishing cleanup levels for 1,2,3-trichloropropane contamination in soils and groundwater.[9] The state of California considers 1,2,3-trichloropropane to be a regulated contaminant that must be monitored. The state of Colorado has also promulgated a groundwater standard although there is no drinking water standard. Although there is not much regulation on this substance, it has proved that TCP is a carcinogen in laboratory mice, and most likely a human carcinogen as well. On a federal scale, there is no MCL for this contaminant. The Permissible Exposure Limit (PEL) in occupational setting for air is 50 ppm or 300 mg/m3. The concentration in air at which TCP becomes an Immediate Danger to Life and Health (IDLH) is at 100 ppm. These regulations were reviewed in 2009.

TCP as an emerging contaminant

TCP does not contaminate soil. Instead, it leaks down into groundwater and settles at the bottom of the reservoir because TCP is more dense than water. This makes TCP in its pure form a DNAPL (Dense Nonaqueous Phase Liquid) and it is, therefore, harder to remove it from groundwater.[6] There is no evidence that TCP can naturally decompose, but it might in favorable conditions. Groundwater remediation of TCP can occur through in situ chemical oxidation, permeable reactive barriers, and other remediation techniques.[10] Several TCP remediation strategies have been studied and/or applied with varying degrees of success. These include extraction with granular activated carbon, in situ chemical oxidation, and in situ chemical reduction.[11] Recent studies suggest that reduction with zerovalent metals, particularly zerovalent zinc, may be particularly effective in TCP remediation.[12][13][14] Bioremediation may also be a promising clean-up technique.[15][16]

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References
  1. NIOSH Pocket Guide to Chemical Hazards. "#0631". National Institute for Occupational Safety and Health (NIOSH).
  2. "1,2,3-Trichloropropane". Immediately Dangerous to Life and Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
  3. Rossberg, M.; Lendle, W.; Pfleiderer, G.; Tögel, A.; Dreher, E. L.; Langer, E.; Rassaerts, H.; Kleinschmidt, P.; Strack (2006). "Chlorinated Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_233.pub2.
  4. Agency for Toxic Substances and Disease Registry (1992). Toxicological Profile for 1,2,3-Trichloropropane (Report). U.S. CDC.
  5. CH2M Hill (2005). Interim Guidance for Investigating Potential 1,2,3-Trichloropropane Sources in San Gabriel Valley Area 3 (PDF) (Report). U.S. EPA.
  6. Cooke, Mary (2009). Emerging Contaminant--1,2,3-Trichloropropane (TCP) (Report). United States EPA.
  7. Basic Questions and Answers for the Drinking Water Strategy Contaminant Groups Effort (PDF) (Report). US EPA. 2011.
  8. "123-TCP". waterboards.ca.gov. Retrieved 2017-12-30.
  9. "18 AAC 75 Oil and Other Hazardous Substances Pollution Control Revised as of May 8, 2016" (PDF). Archived from the original (PDF) on 2017-02-11. Retrieved 2018-11-26.
  10. Stepek, Jan (2009). Groundwater Information Sheet: 1,2,3-Trichloropropane (TCP) (PDF) (Report). California State Water Resources Control Board.
  11. Tratnyek, P. G.; Sarathy, V.; Fortuna, J. H. (2008). "Fate and remediation of 1,2,3-trichloropropane". 6th International Conference on Remediation of Chlorinated and Recalcitrant Compounds: Monterey, CA (PDF). Paper C-047. Archived from the original (PDF) on 2012-03-30. Retrieved 2018-11-26.
  12. Sarathy, Vaishnavi; Salter, Alexandra J.; Nurmi, James T.; o’Brien Johnson, Graham; Johnson, Richard L.; Tratnyek, Paul G. (2010). "Degradation of 1,2,3-Trichloropropane (TCP): Hydrolysis, Elimination, and Reduction by Iron and Zinc". Environmental Science & Technology. 44 (2): 787. doi:10.1021/es902595j.
  13. Bylaska, Eric J.; Glaesemann, Kurt R.; Felmy, Andrew R.; Vasiliu, Monica; Dixon, David A.; Tratnyek, Paul G. (2010). "Free Energies for Degradation Reactions of 1,2,3-Trichloropropane from ab Initio Electronic Structure Theory". The Journal of Physical Chemistry A. 114 (46): 12269–82. doi:10.1021/jp105726u. PMID 21038905.
  14. Salter-Blanc, Alexandra J.; Tratnyek, Paul G. (2011). "Effects of Solution Chemistry on the Dechlorination of 1,2,3-Trichloropropane by Zero-Valent Zinc". Environmental Science & Technology. 45 (9): 4073–4079. doi:10.1021/es104081p.
  15. Pavlova, Martina; Klvana, Martin; Prokop, Zbynek; Chaloupkova, Radka; Banas, Pavel; Otyepka, Michal; Wade, Rebecca C; Tsuda, Masataka; Nagata, Yuji; Damborsky, J (2009). "Redesigning dehalogenase access tunnels as a strategy for degrading an anthropogenic substrate". Nature Chemical Biology. 5 (10): 727–33. doi:10.1038/nchembio.205. PMID 19701186.
  16. Yan, J.; Rash, B. A.; Rainey, F. A.; Moe, W. M. (2009). "Isolation of novel bacteria within the Chloroflexi capable of reductive dechlorination of 1,2,3-trichloropropane". Environmental Microbiology. 11 (4): 833–43. doi:10.1111/j.1462-2920.2008.01804.x. PMID 19396942.
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