T Nation

Organic Chemistry Buffs


#1

I'm teaching a short (3-4 day) lesson to 10th graders on organic chemistry in chemistry class this year. I took organic about 14 years ago, and now when I go on the internet, or use textbooks for naming procedures I am finding different answers.

The simplest one would be CH2OHCH2CH3, propyl alchool.

I would have named this 1-propanol, but some sites I am looking at today say propane-1-ol as the "official" name.

Another example would be CH2OHCH2CH2CHOOH. I would have simply named this 1-butanoic acid-4-ol,(is this OK?). Some sources are saying butane-1-carboxylic acid-4-ol, or 4 hydroxy-1-butanoic acid.

Or CH2BrCH2OH I would call 2-bromo-1-ethanol, but here I am seeing 2-bromoethane-1-ol.

Are any or all of these OK?

Thanks a bunch.


#2

It doesn't matter. As far as I know, both the old naming systems and new ones are accepted.


#3

Also, don't forget to tell them about the cool stuff in organic, otherwise they're going to be bored out of their minds. Naming is boring stuff.


#4

Make sure you run them through the oxidative processes of ethanol versus methanol. It's a great example of how one methyl group can make a big difference: waking up with a hangover versus waking up blind.
And the chemistry is really simple to illustrate.


#5

maybe talk about making drugs. perhaps start your own meth lab?lol
nah for real, isomerism with pharmamceuticals, stuff like that might be fun


#6

Thanks. I always thought it was funny to denature alcohol as a way of keeping people from drinking it-you know, "this is dangerous stuff, and you shouldn't be drinking it, so were going to put something real dangerous in there."

Anyway, I am not familiar with the exact chemistry here. I thought it had something to do with Methanol having a greater capacity to dehydrate. Fill me in, or I'll look it up.


#7

We did tie-dying with cellulose binding organic dyes. I also plan to have them use the Tollen's aldehyde reaction to silver a bottle, and to synthesize several esters with distinguishing odors. We've also talked about stereoisomers in amino acids, and hexose.

Any other ideas would be appreciated.


#8

as you know, the "official" names you're seeing is based on the priority rankings of functional groups; the higher ranked group gets the backbone of the name:

  1. carboxylic acids
  2. esters
  3. acyl halides
  4. amides
  5. aldehydes
  6. ketones
  7. alcohols
  8. amines
  9. ethers

here's a more comprehensive ranking of functional groups: http://www.muhlberg.edu/depts/chemistry/chem201woh/FGPRIORT.htm


#9

yes. bring in real-world applications as much as you can. i actually enjoyed synthesis and spectroscopy once our professor explained their relevance in the medical, dental, pharm. fields, etc.

ok, i'm exaggerating a little but it sure did make it easier to learn.


#10

Any of those names would be considered correct by a synthetic chemist. When I look up a chemical for an experiment often times I will find up to 8 different names for the same molecule. This is due to the complexity of the IUPAC naming system when dealing with larger molecules. So what many synthetic labs and companies do is break the names down into a combination of common names combined with an IUPAC notation. In general what you want out of a name: "Can you draw the structure from the name."

In general CH3CH2CH2OH is simply propanol, or propan-1-ol (my preferred naming scheme, more of a british scheme), 1-propanol is more of a modern version....my understanding. Either are correct.

Good luck with your class! May the force be with you.


#11

I would like to echo what's been said about bringing real life applications/examples into your lesson plan.

Also, fun experiments are always good. I don't know how much you can do, if you have fume hoods, etc. Being as it's high school I would say just try to make it as interesting as possible, since a lot of those kids may never take OChem in college anyways, and those that do won't have learned enough from a 3-4 day unit on orgo to give them much of in terms of a base to build off of.


#12

Naming is the only stuff I understand. All the "cool stuff" makes my head hurt.


#13

This has nothing to do with the CU BUFFS does it?

damn.


#14

Its optional in the curriculum, but I use it primarily because it provides so many opportunities to talk about isomerism, and the fact that molecules have some character to them (polarity, H-bonding, geometry).


#15

In your body an alcohol is oxidized to an aldehyde and then to a carboxylic acid.

Thus:
Ethanol is oxidized to acetaldehyde and then to acetic acid (vinegar is a weak form of acetic acid).
This process leaves you dehydrated which is one reason why you have a hangover.

Whereas:
Methanol is oxidized to formaldehyde (toxic) and then to formic acid (which attacks the retinas of your eyes).

You should also impart on them some practical information regarding solvents and how they work (like dissolves like) and basic information on what a polymer (plastic) is.

This could be a very cool and informative course for these kids if you work at it. Sure, the IUPAC stuff is necessary, but you gotta make it interesting and fun. Yes, organic chemistry can be fun (I loved it). Explain to them what organic REALLY means and how benzene is organic while water is not.

And never, never protonate a cyanide compound.


#16

Ooooohhh, stereochemistry. Now that usually culls the herd (along with P-chem). Doubt you'll have time for that.

Hydrogen bonding is important as it takes so much energy to break those bonds. This explains many of the unique charcteristics of water (and how many of our bodily processes operate).

Remember, don't overload them. Keep it simple. Give them enough to spark their interest and learn something. They may wind up wanting to learn more.


#17

Always use IUPAC, not trivial, nomenclature. It's not the most commonly seen, but is the most respected by organic chemists.


#18

That's very interesting, thanks. My wife told me that they give a patient ethanol if they have methanol poisoning. She thinks it has to do with it having a greater affinity for the enzyme or enzymes responsible for the oxidation. I had them build and draw structures for enantiomers and diasteriomers back when we did different forms of isomerization in the last "unit". I could make polymers with PVA. I also might do a distillation. In 9th grade, I had them do a simple distillation with water, isopropanol and a salt, and then they used a flame test on the salt and plated out crystals on a microscope slide. What's really neat is getting kids in the 9th grade introductory class and then again in chem in 10th or 11th.

Any idea what happens if I add iodine crystals to nitric acid?


#19

That's what I wanted to do, but I took organic last in '92-'93 and apparently there were a few changes? Again, what I would have called 2-butanol, they are now saying should be
butane-2-ol. Is that right?


#20

How about throwing in some CSI type of stuff? I hear the kids like that kind of thing nowadays. You could give a really basic intro into GC, mass spec and NMR.