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 Ketones Alcohols and Phenols Family Science Night Volunteers meet after next Tuesday’s Lablecture Next time: Unknown #2: Carboxylic Acids, Esters, Amides. Amines.

(What needs to be remembered for a good mp.measurement?)Mp. for solids (What needs to be remembered for a good mp.measurement?) Bp. for liquids a physical characteristic, defines a compoundRefractive index for liquids a physical characteristic, defines a compound information?Ignition test information? Test for unsaturation Beilstein test for halogen (p.626) Preliminary Tests Aldehydes and Ketones Alcohols and Phenols

What type of information do you get if your unknown 1. is soluble in water? 2. is soluble in NaOH and in NaHCO 3 ? 3. is soluble in NaOH only, not in NaHCO 3 ? 4. is soluble in dilute HCl solution? 5. is soluble only in conc H 2 SO 4 ? 6. is not soluble in any of the above solvents? Solubility Tests (pp. 626 – 627)

Aldehydes and Ketones functional 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 oxime semicarbazone 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 1 o, 2 o alcohols, amines…!) Lucas test for 3 o alcohols, 2 o alcohols (slow): Phenols only: Complexation with Fe 3+ Preliminary tests Solubility Classification tests Derivatives Spectra

Alcohols IR: H-NMR: Exchange with D 2 O 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

Next time: Unknown #2: Carboxylic Acids, Esters, Amides Amines (Cl, Br, nitro) MiniQuiz on today’s class!