Questions of the Day:

Which test allows you to distinguish between

1) an aldehyde and a ketone?

2) an aldehyde and a primary alcohol?

3) an alcohol and a phenol?

Today:

“Unknowns”

- Review of Preliminary Tests and Solubilities

Unknown #1:- Classification tests and derivatives for:

Aldehydes and KetonesAlcohols and Phenols

Family Science Night Family Science Night Volunteers Volunteers

meet after next meet after next Tuesday’s LablectureTuesday’s Lablecture

Next time:Unknown #2:

Carboxylic Acids, Esters, Amides. Amines.

• Mp. for solids (What needs to be remembered for a good mp.measurement?)(What needs to be remembered for a good mp.measurement?)

• Bp. for liquids

• Refractive index for liquids a physical characteristic, defines a compounda physical characteristic, defines a compound

• Ignition test information?information?

• Test for unsaturation

• Beilstein test for halogen (p.626)

Preliminary TestsAldehydes and KetonesAlcohols and Phenols

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?

Solubility Tests (pp. 626 – 627)

Aldehydes and Ketonesfunctional group?

•Typical properties….

• Mp., bp., solubility…

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

Aldehydes and Ketones

IR:

H-NMR:

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

2,4-dinitrophenylhydrazone

Classification Tests for Aldehydes and Ketones

also a good derivative! 1. What are desirable properties of a derivative? 2. What is the purpose of preparing a derivative?

→Prepare two good derivatives of each unknown. Recrystallize from ethanol/water.

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

• Tollens Test:

• Jones (chromic acid): check reagent! Test is also positive for …..?

• Schiff reagent: check reagent!

Always do with a known compound to compare!

Aldehydes and Ketones

To distinguish between aldehydes and ketones:

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

Aldehydes and Ketones Derivatives

Imines:2,4-dinitrophenylhydrazone

oximesemicarbazone

• 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 (also positive with 1o, 2o alcohols, amines…!)

• Lucas test for 3o alcohols, 2o alcohols (slow):

• Phenols only: Complexation with Fe 3+

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

Alcohols

IR:

H-NMR:

Exchange with D2O

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

Phenols Sample Compound: Phenol

IR

H-NMR

Alcohol and Phenol Derivatives

• with 3,5-dinitrobenzoyl chloride

• urethanes

Similarly: Naphthyl urethanes

• Preliminary tests

• Solubility

• Classification tests

• Derivatives

• Spectra

Anthocyanin Colors:Phenolic plant pigments responsible for

blue, purple, pink colors in plants. Can complex with metal ions in soil,

are pH sensitive

- glucose

Cl-

O

O

OH

HO

OH

OCH 3

OCH 3

+

Malvidinan anthocyanin in blue grapes

Next time:

Unknown #2:

• Carboxylic Acids, Esters, Amides

• Amines

• (Cl, Br, nitro)

MiniQuiz on today’s class!