This news item was adapted by students Christy DeLaporte, Shanta S., Karrie Milam, and Emily Gorman as part of their Chemistry 212 Collaborative Group Activities in Winter Semester 2000 under the guidance of Prof. Rainer Glaser.

Glaser's "Chemistry is in the News"
To Accompany Wade Organic Chemistry 4/e.
Chapter 26. Polymers.


For each of the following questions, please refer to the following article:

Watered Down Hairspray
by Alan Bruzel (@about.com, 2000)
Useful links when reading the article:
chlorofluorocarbons
US Environmental Protection Agency
The European Union's (EU) Solvent Emissions Directive




Editorial Comments

 Freon is currently the second largest (in volume) smuggled import from Mexico into the United States. It is second only to marihuana. This unfortunate smuggling activity proceeds despite the knowledge of the hazards that freon poses to the environment. Freon, before being banned due to its harmful effects on the stratospheric ozone layer, was used as a propellant in hairsprays (aerosols). (Find out how hairspray is made through the Mad Scientist Network. Just type in “Hairspray” and go to the “RE: Hairspray” option.)  Freon, or dichlorodiflouromethane, (Chemfinder) was initially thought to be a most favorable industrial compound because of its relative non-toxicity, its unreactive behavior and its ability as an excellent and efficient coolant.  Unfortunately, two major environmental problems arose as a result of the excessive use of this compound over the past 40 years.   The first problem is the depletion of the ozone layer as mentioned before.  The second is the resultant global warming due to the increase of gases in the upper atmosphere which have the capabilities to absorb large amounts of infra-red waves, thus trapping the heat within our stratosphere that would otherwise escape back into outer atmosphere. Read about freon and regulatory information regarding air and radiation at the USEPA website.

 According to John Christie of La Trobe University in Victoria, Australia there are essentially two types of freon substitutes that are used in today’s products (such as aerosols) hydrogenated flourocarbons and hydrocarbons.

Hydrogenated flourocarbons are non-toxic and do not exist for lengthy periods of time in our environment. Even if these compounds make it to the stratosphere where a reaction with the ozone layer would normally take place, their fragments are not efficient in reacting with and breaking down ozone molecules.  A drawback to using hydrogenated flourocarbons is the resulting decay products of hydrogen flouride and flouracetic acid both of which can be harmful to the environment.

Hydrocarbons such as propane and butane could be ideal substitutes due to their non-toxicity. Though their decay products are toxic, they already naturally exist in our environment so they are not of major concern. Unfortunately, hydrocarbons (or VOCs) as a general rule are not favorable refrigerants and are rather flammable. If you have questions regarding aerosols, freon, or other science-related queries visit www.madsci.org for more information.


Pertinent Text References
Chapter 26. Polymers.  
Chapter 11. Reaction of Alcohols.
Chapter 14.  Ethers, Epoxides, and Sulfides.  

Questions

Question 1:   (SCL) Why don’t current aerosol hairsprays create a fine mist, as in the past?

                Answer

Question 2: 1.      (PSP) Should aerosol sprays be banned for reasons of environmental safety and if so, is this an economically reasonable proposition? (see EPA and chloroflourocarbon links).


                Answer

Question 3:  (RQD)  How do you synthesis polyurethane?

                Answer:  see link (same as link above).  

Question 4:      (FAR)  Discuss how CFCs destroy the ozone layer through writing a chemical reaction and determining the molecules produced. Also identify the catalyst in the reaction to better understand why CFCs are so dangerous to the ozone layer. (Hint)

                Answer

Question 5:     (ICR)  In referring to the answer you found to question #4 define the greenhouse effect and how the lifetime of freon aids in its enhancement.

                Answer