1,2,3-Trichloropropane
Encyclopedia
1,2,3-Trichloropropane (TCP) is a chemical compound that is commonly used as an industrial solvent. Although it is not currently labeled as a contaminant by the United States federal government, new research shows that it could have severe health effects. Currently, only California has significant regulation on this compound.
of propylene
. Other reported methods for producing 1,2,3-trichloropropane include the addition of chlorine to allyl chloride
, reaction of thionyl chloride
with glycerol
, and the reaction of phosphorus pentachloride with either 1,3- or 2,3-dichloropropanol. TCP also may be produced as a byproduct of processes primarily used to produce chemicals such as dichloropropene (a soil fumigant), propylene chlorohydrin, propylene oxide
, dichlorohydrin, and glycerol
.
and polysulfides and and an industrial solvent.
, permeable reactive barriers, and other remediation techniques. 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. Recent studies suggest that reduction with zerovalent metals, particularly zerovalent zinc, may be particularly effective in TCP remediation. Bioremediation may also be a promising clean-up technique.
Production
1,2,3-Trichloropropane can be produced via the chlorinationChlorination
Chlorination is the process of adding the element chlorine to water as a method of water purification to make it fit for human consumption as drinking water...
of propylene
Propylene
Propene, also known as propylene or methylethylene, is an unsaturated organic compound having the chemical formula C3H6. It has one double bond, and is the second simplest member of the alkene class of hydrocarbons, and it is also second in natural abundance.-Properties:At room temperature and...
. Other reported methods for producing 1,2,3-trichloropropane include the addition of chlorine to allyl chloride
Allyl chloride
Allyl chloride is the organic compound with the formula CH2=CHCH2Cl. This colorless liquid is insoluble in water but soluble in common organic solvents. It is mainly converted to epichlorohydrin, used in the production of plastics. It is a chlorinated derivative of propylene.-Production:Allyl...
, reaction of thionyl chloride
Thionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...
with glycerol
Glycerol
Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...
, and the reaction of phosphorus pentachloride with either 1,3- or 2,3-dichloropropanol. TCP also may be produced as a byproduct of processes primarily used to produce chemicals such as dichloropropene (a soil fumigant), propylene chlorohydrin, propylene oxide
Propylene oxide
Propylene oxide is an organic compound with the molecular formula CH3CHCH2O. This colourless volatile liquid is produced on a large scale industrially, its major application being its use for the production of polyether polyols for use in making polyurethane plastics...
, dichlorohydrin, and glycerol
Glycerol
Glycerol is a simple polyol compound. It is a colorless, odorless, viscous liquid that is widely used in pharmaceutical formulations. Glycerol has three hydroxyl groups that are responsible for its solubility in water and its hygroscopic nature. The glycerol backbone is central to all lipids...
.
Uses
Historically, TCP has been used as a paint or varnish remover, a cleaning and degreasing agent, and in the production of pesticides. Currently, it is also being used as a chemical intermediate in the process of making chemicals such as hexafluoropropyleneHexafluoropropylene
Hexafluoropropylene is a compound with the formula C3F6. It is a fluorocarbon alkene in which all of the hydrogen atoms in propylene are replaced by fluorine atoms. It is used as a chemical intermediate....
and polysulfides and and an industrial solvent.
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.Existing regulation
As of now, only the state of California has any regulation on 1,2,3-trichloropropane. Even there, it is only viewed as an unregulated contaminant that should be monitored. 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 (maximum concentration level) for this contaminant. In California, there is only a notification level of .005 ppb (parts per billion) in groundwater. However, other safety and health departments have created limits on how much exposure a person can have to TCP safely. The Permissible Exposure Limit (PEL) 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.Proposed US federal regulation
In a new drinking water project that was proposed by the US Environmental Protection Agency (EPA), TCP is one of sixteen chemicals that are being considered for regulation. These sixteen chemicals are all suspected human carcinogens.TCP as an emerging contaminant
TCP does not contaminate soil. Instead, it leaks down into ground water and settles down at the bottom of the ground water 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. 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 oxidationIn situ chemical oxidation
In situ chemical oxidation , a form of advanced oxidation processes and advanced oxidation technology, is an environmental remediation technique used for soil and/or groundwater remediation to reduce the concentrations of targeted environmental contaminants to acceptable levels...
, permeable reactive barriers, and other remediation techniques. 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. Recent studies suggest that reduction with zerovalent metals, particularly zerovalent zinc, may be particularly effective in TCP remediation. Bioremediation may also be a promising clean-up technique.