3
$\begingroup$

PTFE (Polytetrafluoroethylene) and FEP (Fluorinated ethylene propylene) have the following chemical formulas:

PTFE formula, from WikipediaFEP formula, from Wikipedia

It's been years since I have taken organic chemistry, but I do remember alkenes have double bonds and alkanes have single bonds. Neither of these compounds have double bonds.

Why do these compound names contain "-ene" in them, instead of "Polytetrafluoroethane" or something?

$\endgroup$
  • 1
    $\begingroup$ I don't know how in blazes you found that; I searched for 30 minutes using those keywords! Thanks for the link. $\endgroup$ – user1717828 Jan 15 '15 at 16:42
  • 1
    $\begingroup$ By the way, I give you a warm welcome to chemistry.SE by marking your question as duplicate! :) $\endgroup$ – M.A.R. Jan 15 '15 at 17:47
  • $\begingroup$ What is SE shorthand for? Also, how can I mark the question as duplicate? $\endgroup$ – user1717828 Jan 15 '15 at 19:05
  • $\begingroup$ Technically not duplicate because monomers are different even though topic is adequately covered. $\endgroup$ – Lighthart Jan 15 '15 at 23:10
  • 2
    $\begingroup$ @user171828 SE = Stack Exchange $\endgroup$ – Lighthart Jan 15 '15 at 23:10
8
$\begingroup$

Polymers follow a slightly different nomenclature system than you are used to in organic chemistry. Instead of naming the polymer after the monomers as they are, we name them after the monomers as they originally were. In other words, a polymer made from ethylene monomers is called polyethylene. Since PTFE and FEP are made from fluorinated ethylene and propylene, we just put "poly" in front of the monomer names. This is despite the fact that after the reaction, the bond order is reduced by one.

| improve this answer | |
$\endgroup$
  • $\begingroup$ This is correct thomij. If you are going to think that way (about the product macromolecule instead of the unit structures that made them, why wouldn't you call them difluoromethylene and call PET, polymethylene; or as you are saying polymethane? If you inspect it after they are single, not double, carbons connected. Since nothing but seemingly arbitrary brackets makes them two carbon units in their chain elongated states? $\endgroup$ – DrAzulene Jul 5 '16 at 19:14
0
$\begingroup$

The compounds are polymers. The unit structure of PTFE is tetrafluoroethene. PTFE is named in accordance with the subunits from which they are polymerized. You can apply the same logic to the second one (you apply the same logic to all polymers). There are no common names for polymers just abbreviations. IUPAC rules do have polymer rules too, so you will necessarily see them adhering to the IUPAC rules. It is, however, a matter of the unit structure in brackets, not the monomer that determines the name.

| improve this answer | |
$\endgroup$

Not the answer you're looking for? Browse other questions tagged or ask your own question.