Presentation on theme: "ORGANIC CHEMISTRY || T.A HAYA S ALSUBAIE Pharmaceutical chemistry department Pharmacy college Princess Nora University."— Presentation transcript:
ORGANIC CHEMISTRY || T.A HAYA S ALSUBAIE Pharmaceutical chemistry department Pharmacy college Princess Nora University
ALDEHYDES AND KETONES
OBJECTIVES Write the functional groups of aldehydes and ketones. Determine chemical and physical properties of aldehydes and ketones. Perform chemical tests to distinguish between aldehydes and ketones.
INTRODUCTION Aldehydes and ketones are simple compounds which contain a carbonyl group. (c=o) (R=alkyl or aryl )
Aldehyde Has at least one hydrogen atom attached directly to carbonyl carbon. Hydrogen atom makes aldehydes very easy to oxidize. ketone Has two alkyl(or aryl) groups attached to carbonyl carbon. Ketones don't have that particular hydrogen atom, resistant to oxidation. Only very strong oxidizing agents like (potassium permanganate solution) oxidize ketones.
PHYSICAL PROPERTIES OF ALDEHYDE Formaldehyde & Acetaldehyde State Liquid color colorless odor pungent odor flammability Blue non-smoky flame solubility completely miscible with water effect on LP neutral structure formaldehyde acetaldehyde
PHYSICAL PROPERTIES OF KETONES Acetone State Liquid color colorless Odorcharacteristic odor FlammabilityBlue non-smoky flame Soloubilitycompletely miscible with water effect on L.PNeutral Structure
Chemical test General test Oxidation test Tollen’s test Fehling test Schiff’s reagent Specific test Na- nitroprussid Iodoform test Salicylic acid test
CHEMICAL TESTS OXIDATION TESTS: 1-Tollens’ silver mirror test: procedure: 1 ml of ald. or ket. + 1 ml of Tollens’ reagent ;then warm in water bath for 2-5 min. General Test: ALDEHYDE SILVER Mirror KETONE NO Reaction
CHEMICAL TESTS General Test: OXIDATION TESTS: 2) Fehling test: procedure: 1 ml of ald. or ket. + 1 ml of Fehling reagent A&B then warm in water bath for 2-5 min. aldehyde Rapidly change in blue color Acetone No reaction
FEHLING TEST Acetone Acetaldehyde Formaldehyde
CHEMICAL TESTS Schiff test: procedure: 1 ml of ald. or ket. + 2 drops of Schiff reagent. General Test: Aldehyde Magenta color Ketone Color slightly appear
SCHIFF TEST: Acetone Acetaldehyde Formaldehyde
CHEMICAL TESTS 1) Na-nitroprussid: procedure: 1 ml of ald. or ket. + 1 ml of Na- nitroprussid + 1 ml of 10% NaOH. Specific tests: Formaldehyde No reaction Acetaldehyde Red color Acetone Red color
CHEMICAL TESTS: Iodoform test: procedure: 1 ml of ald. or ket. + 3 ml of 30% NaOH+ 1 ml of I2 solution then warm in water bath for 2-5 min.( add more than 1 ml of I2 if you need ) Specific tests: Formaldehyde No reaction Acetaldehyde Yellow ppt. acetone Yellow ppt.
IODOFORM TEST Acetaldehyde Formaldehyde Acetone
Formaldehyde Crimson red color Salicylic acid : procedure: 1 ml of formaldehyde + few amount of salicylic acid + 2 drops of conc. H2SO4. Specific tests: CHEMICAL TESTS:
SALICYLIC ACID TEST Formaldehyde
PRE-LAB QUESTIONS Give a structure of a compound that contains the following functional groups: - Aldehyde - Ketone Why can distinguish between an aldehyde and a ketone using Tollen’s Reagent ?