Dr. Glaser’s “Chemistry in the News” HMO* style
To Accompany Wade, Organic Chemistry, 4/e.
Chapter 6  Alkyl halides:  Nucleophilic Substitution and Elimination
Chapter 7  Structure and Synthesis of Alkenes
Chapter 8  Reactions of Alkenes
Chapter 2.11-2.13  Intermolecular Bonding

 


WE'LL STICK AT NOTHING, March 25, 1999

The Article from DuPont

 

Editorial Chapter 6


Do you know what some may argue is the most important discovery for the modern plastics industry?  You may be surprised to find it in your kitchen cabinets!

Roy J. Plunkett was certainly surprised in the 1930s when he accidentally invented what is now known as Teflon.  In fact, many households today take their non-stick cookware for granted.  Little do they know that Teflon, which gives cookware it's non-stick property, is a polymer composed of tetrafluoroethylene (C2F4) monomers. 

As discussed in this article, Teflon also aids in keeping materials sterile.  By replacing ethene's hydrogens with fluorine atoms, the chemical attains a slippery quality that prevents bacteria from binding to it.  Since molecules connect by sharing or exchanging electrons, it reasons that fluorine, the most electronegative element, resists interactions with other molecules.  The fluorine's large size shields the interior carbons, preventing them from reacting-thus nothing sticks to Teflon.

Teflon's lack of chemical reactivity lends it to literally endless possible uses.  It is a well-known registered trademark of the Dupont Corporation, which has promoted their product in a variety of foreign and domestic markets. One interesting use in the field of chemical science is the production of bottles for storage of the reagents used in trace analysis.  Teflon, as well as improvements in detection, allows impurities to be detected at the sup-ppb level.

While some claim there are hidden environmental dangers of Teflon and its fumes, we simply recommend not keeping your pet parakeet in the kitchen.  Teflon has become a household expression used far beyond the bounds of non-stick cookware and its chemical properties-even used to poke fun at the Prime Minister of England.

 

 

Question 1: What is the formula and organization of the monomer unit of Teflon?

Answer 1: the monomer unit of Teflon is Tetrafluoroethylene, which is C2F4. The Carbons are SP2 hybridized, and share a double bond. Two fluorine atoms are bonded to each carbon, and the geometry around the carbon atoms is trigonal planar.

Question 2: How might the monomer unit of Teflon be synthesized? Give a detailed mechanism for the synthesis.

Answer 2: To synthesize the monomer unit of Teflon, tetrafluoroethylene, we need to start with ethynyl halide, (XC2H). First we reduce the triple bond with fluorines to give us (HXC2F2), or difluoro-halo-ethylene. After that we reduce the double bond once again witth fluorines, giving us (HXC2F4), tetrafluoro-halo-ethane. The last step is to eliminate the HX. This restores the carbon to carbon double bond and gives us our final product, (C2F4), tetrafluoroethylene.

Question 3: A major benefit to these new super-slippery polymers is improved hygiene. What are some reasons this new way of keeping things sterile might be better than the old way of heat sterilization by autoclaves? Are there any reasons that the old way might be better?

Answer 3: There are many answers to this question. We could bring up that heat sterilization must be done over and over in contrast to the polymer which must only be applied once. Heat sterilization takes time and energy, but has been proven to work. Also, just because bacteria cannot stick to these new slippery polymers on a chemical level, does that imply that on a larger scale the polymer coated object will always be sterile? This new method of sterility certainly needs a little lab experience before it's considered trustworthy.

Question 4: How are the intermolecular Van der Waal's forces affected when we replace the hydrogens in ethane with fluorines to make the monomer unit of Teflon? Also, why are the Van der Waal's forces affected at all?

Answer 4: The Van der Waal's forces are almost completely eradicated between the Teflon molecule and outside molecules. This is because when we replace the hydrogens with fluorines, the Teflon molecule as a whole becomes very inert. The fluorine atoms prevent the temporary dipole moments necessary for the Va der Waal's forces to exist.

Question 5: How might the use of these new super-slippery halogen saturated polymers eventually affect the environment? What might be some of the dangers associated with these new polymers?

Answer 5: This question is the open-ended philosophical/social/political question. There are many acceptable responses as long as some thought is put into them. =) cheerio.



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