Forum Rules: Read This Before Posting


Topic: Several Questions  (Read 3737 times)

0 Members and 1 Guest are viewing this topic.

Megapuppy

  • Guest
Several Questions
« on: August 20, 2005, 09:03:58 PM »
I have been researching several organic chemistry questions on the web for several days now and have met with limited success.

The problem is that the questions are pretty basic but extremely specific.

They are beyond my limited knowledge of the subject, and I am unable to do any offline research due to the fact that I have recently moved and there are no colleges nearby with anything approaching a real science department.

I have managed to find the data for two of the six questions, but I have hit rock bottom on the rest. I would appreciate any data or a link to a website that could provide data for these questions:

How would you isolate and purify cholesterol from human gallstones?
How would you prepare p-aminobenzoic acid from p-toluidine and test for purity of the product?
How would you isolate rhodopsin and test its photo sensitive properties?
How would you determine whether a sample of an unknown organic compound was a fatty acid, aldehyde, ketone, or alcohol?

I have searched these forums to see if any of the questions were addressed, and did not find any evidence of it.

I appreciate any help you can offer me, and thank you very much.

Offline Yggdrasil

  • Retired Staff
  • Sr. Member
  • *
  • Posts: 3199
  • Mole Snacks: +482/-21
  • Gender: Male
  • Physical Biochemist
Re:Several Questions
« Reply #1 on: August 21, 2005, 02:22:18 PM »
How would you prepare p-aminobenzoic acid from p-toluidine and test for purity of the product?

Potassium permanganate or a Jones oxidation (CrO3 and sulfuric acid) would probably work.  You could extract the p-aminobenzoic acid from your reaction mixture using aqueous base.  To test the purity of your product, you can perform a titration.

Megapuppy

  • Guest
Re:Several Questions
« Reply #2 on: August 22, 2005, 02:44:28 PM »
Thank you, you have been very helpful.

I have also been reviewing some of the links from this forum and some have been very intersting as well.

Offline FeLiXe

  • Theoretical Biochemist
  • Chemist
  • Full Member
  • *
  • Posts: 462
  • Mole Snacks: +34/-7
  • Gender: Male
  • Excited?
    • Chemical Quantum Images
Re:Several Questions
« Reply #3 on: August 22, 2005, 04:23:20 PM »
Quote
How would you determine whether a sample of an unknown organic compound was a fatty acid, aldehyde, ketone, or alcohol?

A few key words, if I have some time I'll elaborate it tomorrow during work.

Fatty acid: 1. low pH
2. water soluble in alkaline solutions
not soluble anymore if you become acidic
(depending on chain length)

Aldehyde: Fehling test (something about oxidizing)

Ketone: you take Di-phenyl-hydrazine, condense it to your ketone to get a Di-phenyl-hydrazone. (a colorful precipitate?)

Alcohol: Lucas test. It even tells you if it's 1°, 2°, or 3°. How it works: no idea (I always forget that)

Maybe the keywords already help you a little bit.
« Last Edit: August 22, 2005, 04:25:23 PM by FeLiXe »
Math and alcohol don't mix, so... please, don't drink and derive!

Sponsored Links