1. Today: Unknown 1 (review) aldehyde, ketone, alcohol, phenol
carboxylic acid, ester, anhydride, amide, amine (Cl, Br, nitro)
Questions?

2. Classification Tests for Aldehydes and Ketones
Preliminary tests
Solubility
Classification tests
Derivatives
2,4-dinitrophenylhydrazone (2,4-DNP)
also a good derivative!
→Prepare two good derivatives of each unknown if possible. Recrystallize from ethanol/water.

3. Aldehydes and Ketones To distinguish between aldehydes and ketones:
Preliminary tests
Solubility
Classification tests
Derivatives
Tollens Test:
Jones (chromic acid): check reagent! Test is also positive for …..?
Schiff reagent: check reagent!
Always do with a known compound to compare!

4. Preliminary tests
Solubility
Classification tests
Derivatives
Aldehydes and Ketones Derivatives Imines: 2,4-dinitrophenylhydrazone oxime semicarbazone

5. Alcohols and Phenols Solubility distinction!
Preliminary tests
Solubility
Classification tests
Derivatives
Spectra
Alcohols and Phenols Solubility distinction!
Solubility:
Alcohols: “neutral”;
Phenols: very weak acids, pKa around 10, except nitrophenols!
Classification tests:
Jones (positive for 1o, 2o alcohols, aldehydes, amines…!)
Lucas test for 3o alcohols, 2o alcohols (slow):
Phenols only: Complexation with Fe 3+

6. Alcohol and Phenol Derivatives
Preliminary tests
Solubility
Classification tests
Derivatives
Spectra
with 3,5-dinitrobenzoyl chloride
urethanes
Similarly: Naphthyl urethanes

7. Refractive Index (confirming liquid unknowns)
the ratio of the velocity of light in air to the velocity of light in a given medium.
sin incident angle/sin refracted angle
a constant at a given temperature.
an important physical property of liquids (and gases and transparent solids!)
Air has a refractive index of at 273 K/760 mm Hg for the yellow sodium D-line at nm.

8. carboxylic acid, ester, anhydride, amide, amine (Cl, Br, nitro)
Unknown #2:
carboxylic acid, ester, anhydride, amide, amine (Cl, Br, nitro)
Functional groups?

9. Preliminary test results?
Preliminary tests?
Solubility
Classification tests
Derivatives
Spectra
Carboxylic Acids
Anhydrides
Esters
Amides
Amines
Nitro
Preliminary test results?
Mp., bp. Which would you expect to have relatively high/relatively low mp.s / bp.s?
Odor Which would you expect to have a bad smell/a pleasant smell (human perspective…)
Color Which would you expect to have a color?

10. What type of information do you get if your unknown
Preliminary tests
Solubility?
Classification tests
Derivatives
Spectra
Carboxylic Acids
Anhydrides
Esters
Amides
Amines
Nitro
Solubility Tests
What type of information do you get if your unknown
1. is soluble in water?
2. is soluble in NaOH and in NaHCO3?
3. is soluble in NaOH only, not in NaHCO3?
4. is soluble in dilute HCl solution?
5. is soluble only in conc H2SO4?
6. is not soluble in any of the above solvents?

11. Carboxylic Acids Good mp.s (consider recrystallization)
Solubility
Classification tests
Derivatives (not done)
Spectra
Carboxylic Acids Good mp.s (consider recrystallization)
Neutralization Equivalent (titration) experimental instructions on our webpage
RCO2H +
NaOH
      
RCO2(–) Na(+)aq.   +   H2O
Derivatives (we do not do them in the lab):
Convert carboxylic acid into acid chloride first, then into amides 1.
+ HCl 2.
Define carboxylic acid by: mp., neutr. equivalent, an ester and its bp.

12. Compare with known ester!
Preliminary tests?
Solubility
Classification tests
Derivatives
Spectra
Esters
Classification Test
a hydroxamic acid
Deep-red to purple
Compare with known ester!

13. Derivatives for Esters
Hydrolyze (experimental instructions on our webpage)
… to its carboxylic acid component (mp.)
Preliminary tests?
Solubility
Classification tests
Derivatives
Spectra
…. and its alcohol component alcohol derivative

14. Amine Derivatives Amines in plant odors … : 1. Picrates
Preliminary tests?
Solubility
Classification tests
Derivatives
Spectra
1. Picrates
2. Benzamides: amine + benzoyl chloride NH 2 OH NO O N +
Amines in plant odors … :
Voodoo Lily
Amorphophallus

15. Alkanes Aromatic Hydrocarbons Alkyl halides MiniQuiz on today’s class
Next time:
Conclusion Unknown 2
Inert Compounds:
Alkanes Aromatic Hydrocarbons Alkyl halides
UV spectra
MiniQuiz on today’s class