Questions of the Day: Which test allows you to distinguish between 1) an aldehyde and a ketone?
-
Upload
jessamine-french -
Category
Documents
-
view
29 -
download
3
description
Transcript of Questions of the Day: Which test allows you to distinguish between 1) an aldehyde and a ketone?
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!