Tetrachloroethylene

Tetrachloroethylene

            Have you ever wondered why you need to take certain clothes to the dry-cleaners instead of throwing them in the washing machine with everything else? Or how do they “dry” clean clothes? Of course you have.

            The answer is quite simple; dry-cleaning is the process of cleaning clothes without the use of water. In the place of water, a different liquid solvent is used because water can damage some materials; this solvent is generally tetrachloroethylene. Also, some clothes can be damaged by the tumbling and rough handling of washing machines in your home, whereas, dry-cleaning is gentle and safe for delicate materials.

            Tetrachloroethylene is also known as perchloroethylene, PCE, and Perc. Perc was first used for dry-cleaning in the 1930’s because it was good at dissolving the substances that stain our clothes and create odors, also, Perc is nonflammable and doesn’t react with other chemicals. Since Perc is not very reactive, nonflammable, and a liquid it became a much safer option for dry-cleaning. Dry-cleaning is the main use of Perc but it can also be used in the automotive industry to clean parts, in the production of chemicals used in air conditioning, and to prevent parts from seizing up [1,5].

            The chemical formula of Perc is CCl₂CCl₂, which means that there are two carbon atoms double bonded together and each carbon is also attached to two chlorine atoms. In 1821 Michael Faraday became the first person to produce Perc, since then the methods of producing it have changed a lot but they are still boring so we’ll say that more chlorine (Cl) is reacted with a precursor to Perc (ClCH₂CH₂Cl or ethylene dichloride) and bumps the hydrogens (H) off to form Perc [6].

            Even though Perc is more safe than what was used for dry-cleaning before it is still very unhealthy, especially for people who work in dry-cleaning and are around Perc all day. Long-term exposure to Perc can lead to cancer, liver failure, kidney failure, and many other terrible health problems. That is why today there are other options that are more safe. They are traditional wet-cleaning, carbon dioxide dry-cleaning, and silicon dry-cleaning. Carbon dioxide and silicon are both safer than Perc and environmentally friendly, however, carbon dioxide dry-cleaning can be expensive. That said, Perc is safe to the customer because of limited exposure, but soon we will probably see it used less and less [1,2,3,7].

 References

[1] Barton, C. 2014. "Tetrachloroethlyene." In Encyclopedia of Toxicology, 498-502. Oak Ridge, TN, USA: Elsevier.

[2] Guyton, Kathryn Z., Karen A. Hogan, Cheryl Siegel Scott, Glinda S. Cooper, Ambuja S. Bale, Leonid Kopylev, Stanley Barone Jr., et al. 2014. "Human Health Effects of Tetrachloroethylene: Key Findings and Scientific Issues." Environmental Health Perspectives 325-334.

[3] Manning, Jennifer. 2006. Are There Realistic Dry-Cleaning Alternatives to Perc? 05 12. Accessed 10 20, 2016. http://environmentalchemistry.com/yogi/environmental/200605drycleaning.html.

[4] Poloso Cleaners (2016) [Photograph]. Retrieved from http://pelosocleaners.com/tips-greening-dry-cleaning/

[5] Science Lab.com. 2013. "Tetrachloroethylene MSDS." ScienceLab.com. 05 21.

[6] United States Environmental Protection Agency. 1989. Locating and Estimating Air Emissions From Sources of Perchloroethylene and Trichloroethylene. United States Environmental Protection Agency.

[7] Vlaanderen, Jelle, Kurt Straif, Avima Ruder, Aaron Blair, Johnni Hansen, Elsebeth Lynge, Barbara Charbotel, et al. 2014. "Tetrachloroethylene Exposures and Bladder Cancer Risk: A Meta-Analysis of Dry-Cleaning-Worker Studies." Environmental Health Perspectives 661-666.