Uses of alkyl halides

Recently, in Organic Chemistry, we have been studying alkyl halides.  Highly substituted (halogenated) alkane compounds have many uses in industry, and even in "everyday" uses.  One example class of a highly substituted alkyl compound are the chlorofluorocarbons (CFCs), such as Freon 12 (pictured below).

Freon, as many of you know, was used as a refrigerant/coolant for many years; however, its used is now curtailed.  According to the Montreal Protocol, of which the United States is a signer, the production of Freon-12 is now banned.  This was in response to the damage that CFCs cause to the ozone layer surrounding the Earth, especially in the Southern hemisphere near Antarctica, Australia, and parts of South America.  The figure below depicts the positioning of the hole in the ozone layer over a multi-year time span.

Possible Bonus Points for Organic Chemistry Students

I want you to research an industrial use of an alkyl halide.  You are to state the name of the compound, its use(s), and any information you find interesting.  Your response should be one paragraph in length.  Be sure to list the website(s) you used to find your information; moreover, you cannot DUPLICATE a compound that another student has already listed in his or her post.




Comments

  1. Compound: Methyl chloroform (1,1,1-trichloroethane)
    Uses: Found in degreasing agents, glue, paint, and cleaning products
    Websites: http://www.epa.gov/ttnatw01/hlthef/trichlor.html
    http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=431&tid=76

    When this compound is exposed to the air, it circulates in the environment for six years. If a person is exposed to this compound for long periods of time they can develop problems in the CNS, heart and liver. Since the CDC and EPA does not have enough information about the compound being cancerous in humans, they have classified methyl chloroform as being a noncarcinogen.

    ReplyDelete
  2. Joy Ferro: Halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) - used as a general anesthetic

    Halothane is the only inhaled general anesthetic that contains bromine. It is a sweet smelling, colorless, light sensitive liquid. Because it was linked to a liver condition that can require surgery or even cause death, its use has greatly decreased. Halothane is inexpensive, so it is still used in third world countries and in veterinarian surgeries.

    http://www.drugs.com/pro/halothane.html
    http://www.absoluteastronomy.com/topics/Halothane

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  3. Alkyl Halide: Chlordane (Octachloro-4,7-methanohydroindane)

    Chlordane is an alkyl halide that is used as an insecticide for corn and citrus crops (among others), termites, lawns, and gardens. Chlordane degrades in the soil for a very long time with a half-life of roughly one year. Chlordane can bioaccumulate in animals, making it highly toxic to fish, shrimp and some species of birds, such as ducks and quails. It has even been linked to affect the human immune system by being an airborne carcinogen. It has also been associated with testicular cancer. The white solid form of Chlordane was sold in the US until 1983 and was banned by the EPA in 1988 and has now been either banned or highly restricted in dozens of countries.

    http://cactus.dixie.edu/smblack/chem2310/ch9/nuggets_Ch9.pdf
    http://jnci.oxfordjournals.org/content/100/9/663.full.pdf+html
    http://organic.com.au/pesticides/Chlorodane/

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  4. Trichloroethylene

    Trichloroethylene (TCE) is an alkyl halide that is presently used as an industrial solvent. Though not as prevalent as it used to be in the mid-late 1900s, TCE can be found in paint, spot removers, carpet-cleaning fluids, metal cleaners, and varnishes. It once was a widely used general anesthetic, but due to its toxicity and discovery of better alternatives, it has now been phased out from the medical field in developed countries. It is still sometimes used as a general anesthetic in third world countries due to its extremely low cost. TCE is also known as one of the most common and persistent groundwater contaminants across the globe due to its previous widespread use (mostly as a metal degreaser and dry cleaning agent), low volatility, and poor disposal practices. In addition, it has also been classified as a probable carcinogen. TCE has also been used by NASA to flush and clean out kerosene-fueled rocket engines.

    http://chem.sis.nlm.nih.gov/chemidplus/ProxyServlet?objectHandle=Search&actionHandle=getAll3DMViewFiles&nextPage=jsp%2Fcommon%2FChemFull.jsp%3FcalledFrom%3Dlite&chemid=0000079016&formatType=_3D

    http://search.ebscohost.com.seu.idm.oclc.org/login.aspx?direct=true&db=a9h&AN=59904548&site=ehost-live

    http://ssfl.msfc.nasa.gov/public-involvement/docs/SSFL_TCE_Final_Fact_Sheet.pdf

    http://www.nda.ox.ac.uk/wfsa/html/u11/u1115_02.htm

    http://www.dhs.wisconsin.gov/eh/chemfs/fs/TCE.htm

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  5. Compound: Polytetrafluoroethylene — poly(1,1,2,2-tetrafluoroethylene)
    or better known as Teflon.

    Polytetrafluoroethylene is a compound that is particularly useful because of its nonstick and inert properties as well as its high chemical resistance. It was discovered accidentally by Roy Plunkett at the DuPont Research Laboratories in 1938, and has since been named Teflon. The substance is used most popularly for coating frying pans due to its nonstick properties and is also used in making artificial body parts due to its tendency not be rejected because of its biological inertness. Its applications extend to anything that needs to be slippery or nonstick, have a low friction coefficient, resist chemical change, and undergo large temperature changes. The high bond dissociation between the carbons and fluorines of this molecule make it almost impossible to break, and the tendency of the fluorines to repel other molecules make this substance "the slipperiest material in the world." Also, Teflon is believed to be the only substance to which a gecko cannot stick.

    http://www.pslc.ws/macrog/ptfe.htm

    http://www.microcare.com/faqdetails.aspx?faqid=77

    http://web.archive.org/web/20071014063923/http://socrates.berkeley.edu/~peattiea/research_main.html

    ReplyDelete
  6. Compound – Carbon tetrachloride – used in fire extinguishers, dry-cleaning businesses, and cleaning products.

    Carbon tetrachloride was a common ingredient in fire extinguishers. It was also used in fabric cleaners and refrigerants. However, there has been a major recall on all fire extinguishers containing carbon tetrachloride and production of cleaners with this substance has been discontinued. The reason for the discontinued production of carbon tetrachloride in household products was due to the discovery of how it affects health in humans. It has been shown to cause major damage to the kidneys and liver and even cause death.

    http://www.epa.gov/ttnatw01/hlthef/carbonte.html#ref1
    http://www.tpromo2.com/ssmag/fire/exting.htm
    http://www.atsdr.cdc.gov/toxprofiles/tp.asp?id=196&tid=35

    ReplyDelete
  7. Sodium fluoroacetate

    Sodium fluoroacetate was introduced as a rodenticide in 1946. It was soon replaced because of just how efficient it was, not only with rodents, but with all mammals, and even birds. It is now available for use against coyotes, as long as the purchaser has a license. This compound is rapidly absorbed from the gastrointestinal tract, however, if it comes in contact with skin, it takes longer for it to absorb. It is colorless, odorless, and is very soluble in water. It was used as an insecticide, herbicide and a repellant, but has since been discontinued under these uses. The main problem with this is that if an animal eats it, and then that animal is eaten by a human, it is very toxic and will poison the human who consumed it second hand.

    http://www.ncbi.nlm.nih.gov/pubmed/17288493
    http://www.inchem.org/documents/pds/pds/pest16_e.htm

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  8. Perfluorodeclin

    Perfluorocarbons such as perfluorodeclin are alkyl halides that have the ability to carry oxygen and, as such, can act as blood substitutes. A particular advantage associated with this attribute is the ability to enhance the clarity of intravascular imaging. Optical coherence tomography is one such form of imaging that is used to locate plaques but, is greatly hindered by the interference of blood. Blood substitutes such as perfluorodeclin are used to enhance image quality for these procedures. This is done by flushing the blood out of a target area by introducing the perfluorocarbon.

    ReplyDelete
  9. Bromomethane (methyl bromide): CH3Br is made by the esterification of HBr with methanol. Bromomethane is implemented in many pesticides as well as fumigants. As a fumigant is is used to help contain the spreading and overgrowth of certain fungi, nematodes, and weeds. Also, in small amounts it can be used in silos containing grains and wheat in order to prevent insects and rats from contaminating the products. Although it does have these fumigation and pesticide uses, it is very harmful to humans if inhaled. The EPA say that "breathing high concentrations of methyl bromide may cause pulmonary edema, and impaired respiratory functions". These are the risks just in small quantities. However, when the chemical is ingested in prolonged quantities, many severe symptoms can arise such as neurological effects, swelling of the liver, kidney damage and even paralysis. Thus, the use of bromomethane should be controlled and used responsibly.

    1)http://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=6323&loc=ec_rcs
    2)http://www.epa.gov/ttnatw01/hlthef/methylbr.html

    ReplyDelete
  10. Dichloromethane (DCM) - CH2Cl2
    This volatile, clear, liquid chemical has many uses, primarily as a paint remover, with other uses as an industrial solvent. It is an anesthetic with an aroma comparable to that of chloroform. It even helps in the process of ripening some fruits, as well as extracting components from other foods. Drinking this compound in vast quantities, in water, can have detrimental neurological effects and can be harmful to the liver. Discharge from drug organizations provides the mixture into drinking water, and its concentration is monitored by the local water supplier.

    http://water.epa.gov/drink/contaminants/basicinformation/dichloromethane.cfm

    http://www.sigmaaldrich.com/chemistry/solvents/dichloromethane-center.html

    ReplyDelete
    Replies
    1. Ethyl Chloride
      Ethyl Chloride is a intermediate or base in paper coating, plastic production, and (in other countries) gasoline additive. It is also used as a anesthetic in minor procedures such as tooth extractions and needle punctures. The vaporization of ethyl chloride at 12 C is manipulated and used, not only as a anesthetic, but as a narcotic as well. Its use as a gasoline additive was banned in America in the 1997 due to the negative impact it had on America's children. It was recorded that the tetraethyl lead which was ethyl chloride mixed with sodium alloy had negative health and mental effects on American children.
      http://www4.hmc.edu:8001/Chemistry/Pb/resources/secret%20history%20of%20lead.pdf
      http://www.britannica.com/EBchecked/topic/194391/ethyl-chloride-C2H5Cl
      http://www.ppg.com/chemicals/chloralkali/products/Documents/English/EthylChloride.pdf
      http://www.pearsonhighered.com/wade8einfo/assets/pdf/wade-ch06.pdf

      Delete
    2. In order for me to accredit your grade, you should email me your name; otherwise, I don't know who you are.

      Delete
  11. Haloalkanes are of wide interest because they are widespread and have diverse beneficial and detrimental impacts. A specific example is bromomethane or methyl bromide. The ocean releases 1-2 million tons of this colorless, odorless, nonflammable gas. It has a tetrahedral shape and it is a recognized ozone-depleting chemical. Methyl bromide is used as a fumigant and pesticide. Exposure may occur during fumigation activities and it is highly toxic. Studies in humans indicate that the lung may be severely injured by the acute (short-term) inhalation of methyl bromide. The primary use of methyl bromide is as a fumigant in soil to control fungi, nematodes, and weeds; in space fumigation of food commodities (e.g., grains); and in storage facilities (warehouses). The chemical formula for methyl bromide is CH3Br, and it has a molecular weight of 94.95 g/mol. Trace amounts of methyl bromide have been found in drinking water. It is also produced naturally algae or kept in the ocean.

    http://www.epa.gov/ttn/atw/hlthef/methylbr.html
    http://www.eco-usa.net/toxics/chemicals/bromomethane.shtml
    http://images.search.yahoo.com/search/images?p=bromomethane&fr=aaplw&fr2=piv-web&tab=organic&ri=4


    ReplyDelete
  12. Ethyl Chloride
    Ethyl Chloride is a intermediate or base in paper coating, plastic production, and (in other countries) gasoline additive. It is also used as a anesthetic in minor procedures such as tooth extractions and needle punctures. The vaporization of ethyl chloride at 12 C is manipulated and used, not only as a anesthetic, but as a narcotic as well. Its use as a gasoline additive was banned in America in the 1997 due to the negative impact it had on America's children. It was recorded that the tetraethyl lead which was ethyl chloride mixed with sodium alloy had negative health and mental effects on American children.
    http://www4.hmc.edu:8001/Chemistry/Pb/resources/secret%20history%20of%20lead.pdf
    http://www.britannica.com/EBchecked/topic/194391/ethyl-chloride-C2H5Cl
    http://www.ppg.com/chemicals/chloralkali/products/Documents/English/EthylChloride.pdf
    http://www.pearsonhighered.com/wade8einfo/assets/pdf/wade-ch06.pdf

    ReplyDelete
  13. Dichlorodiphenyltrichloroethane (commonly known as DDT)
    Use: insecticide

    DDT is an insecticide that has been widely used in the past to prevent insect damage to crops and to decrease insect borne disease among animal and human populations. In 1972 the use of DDT was banned by the Environmental Protection agency for its harmful affects on the environment. DDT affects many animals adversely by accumulating in fatty tissues. It is difficult to eliminate from an environment once introduced, and can travel long distances in the upper atmosphere.


    http://www.epa.gov/pesticides/factsheets/chemicals/ddt-brief-history-status.htm
    http://www.chem.duke.edu/~jds/cruise_chem/pest/pest1.html

    ReplyDelete
  14. trichloromethane (chloroform)

    Chloroform is a clear liquid with an ether-like odor and a slightly sweet taste. It was originally used as an anesthetic, most famously in 1853 when English physician John Snow administered it to Queen Victoria during the birth of Prince Leopold, her eighth child. Although it is a naturally occurring chemical, most of the chloroform sold (like the containers in the lab) is synthetic. Chloroform is used to make coolants and as a dry cleaning spot remover. It can also be formed when other chlorine containing compounds break down. For example trace amounts can be found chlorinated drinking or swimming pool water. Chlorinated drinking water is usually necessary to prevent water borne diseases from spreading. Also, chloroform evaporates very quickly. People can be exposed to chloroform by accidently inhaling the chemical when they are doing laundry (another reason why I do laundry every two weeks) or bathe with contaminated water. Chloroform can actually pass through the victim’s skin when they are handling it (and that is why we wear gloves when we open packages for science)!

    This stuff is potent! After exposure to a level of 100 ppm of chloroform in the air, a person may feel tired, dizzy, and have a headache. Chloroform is suspected of causing cancer, because liver and kidney tumors have been documented in laboratory animals. Chloroform can pass through the placenta and enter the bloodstream of a developing baby. Chloroform is most famously known as a tool for rapists. Since chloroform is rapidly flushed from the body, it is hard to detect in the body. Also, since it can be formed in the body from the exposure to other substances, levels found in tests cannot always be linked to just chloroform exposure. It’s dangerous stuff, so you gotta respect the chemistry, yo!

    http://www.britannica.com/EBchecked/topic/113697/chloroform-CHCl3
    http://www.dhs.wisconsin.gov/eh/chemfs/fs/chloroform.htm

    ReplyDelete
  15. Compound: Isoflurane
    Use: Inhalational anesthesia
    Isoflurane is a general anesthesia that is administered through inhalation. It is can be stored for long periods of time in its liquid form which is clear, colorless, and has a strong ethereal odor. It is a relatively potent anesthetic requiring only 1-3% concentration in an oxygen or nitrous oxide mixture to achieve suitable anesthetic affects for surgery. It can cause respiratory depression and hypotension proportional to the concentration used. One benefit of isoflurane is that it quickly induces anesthesia and recovery is equally rapid. Because of the strong odor, isoflurane is usually used to maintain or induce a deeper anesthesia. Other anesthetic agents are used to initially sedate the patient. There are several uncommon but severe side effects from using isoflurane. These include and is not limited to: hepatic necrosis, hepatic failure, cardiac arrest, malignant hyperthermia, and elevated carboxyhemoglobin levels. Isoflurane acts as a pain reliever and a muscle relaxant by altering neuronal and muscular excitability. The mechanism of actions it thought to occur by decreasing the ability of neuronal and muscular cell to communicate through gap junctions. Additionally, isoflurane is thought to alter the function of channels that are responsible for the propagation of action potentials.

    http://www.medicines.org.uk/emc/medicine/41/SPC/Isoflurane+(inhalation+anaesthetic)/
    http://livertox.nih.gov/Isoflurane.htm
    http://www.rxlist.com/forane-drug/indications-dosage.htm
    http://www.drugbank.ca/drugs/DB00753

    ReplyDelete
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