9Nomenclature Common names - ketones Some are always used - Others name each R group and end with “ketone”
10Physical Properties Carbonyls: Cannot form H bonding with each other: There is NOT an H connected to a F, N, OAldehydes and Ketones are POLAR molecules and form dipole interactionsGives higher boiling and melting points
11Physical Properties Aldehydes and Ketones can form H bonds with water! solubility in water is about the same as alcoholsyes!
12Physical Properties Strong odors Ketones generally have pleasant odors perfumes, flavoring agentsAldehydes odors varysome pleasantcinnaminaldehyde, vanillinsome not pleasantformaldehydeMany are found in natural products
13How do you make Aldehydes? Aldehydes from Oxidation of 1o alcoholsProblem is over oxidation to ACID!Practice a couple …………..
14How do you make Ketones? Ketones from Oxidation of 2o alcohols Practice a couple …………..
15Oxidation of Aldehydes Aldehydes are easily oxidizedKMnO4K2Cr2O7even air oxidation carboxylic acid!
16Oxidation of Ketones Ketones resist oxidation: under mild or normal conditions, no reactionmore severe conditions yield mixturesCO2 and H2O under extreme conditions[O]This difference in reactivity can be used toTell the difference between an aldehyde and ketone
18Reaction 1. Oxidation – Tollens Test - Benedicts Test 2. Reduction – Hydrogen addition– NaBH4 reagent3. Addition of Alcohols – hemiacetal/acetaland tautomerism
19Tollen’s Test The Silver Mirror Test Ag(NH3)2+ + aldehyde Oxidation of AldehydesAg+ ion in aq. ammoniaNO reaction with KETONESAg(NH3) aldehydeSilver MirrorAg NH Ag(NH3)2+Ag(NH3)2+ + RCHO Ago + RCOO- + 4NH3
20Benedict’s Test Cu++ + aldehyde Cu+(oxide) + acid Oxidation of AldehydesCu++ ion, aqueousOrange to red ppt.NO reaction with KETONESCu2+Cu+Cu aldehyde Cu+(oxide) acid
21Benedict’s TestOxidation of Aldehydesoverall reactionCu2O
22Chemical Properties - Addition to C=O Other reactions are ADDITION ReactionsBond is polar + and -Negatives are attracted to CPositives are attracted to O-+B
23Addition of H2 Reduction to Alcohols Hydrogen gas and a catalyst (Ni, Pd, Pt)Similar to alkene to alkane reductionB
24Addition of H2 Reduction to Alcohols Will reduce ketones to 2o alcoholsSlower reaction than reduction of C=CC=C is reduced faster (first) if both C=O and C=CB
25Addition of H2 using NaBH4 Reduction to AlcoholsNaBH4 does not allow the reaction of the carbon carbon double bondB
26Addition of AlcoholIn the addition of R-OH to form an “acetal” the First step is the formation of a “hemiacetal”This is when an -OH and -OR are both on same CB
27Formation of AcetalsIF strong acid (HCl) is present, a second alcohol reacts to form the acetal (two -OR groups on C)+ H2OB
28Addition of Alcohol - Acetals Step 1Step 2+ H2OB
29Formation of Acetals ? Addition of R-OH acid catalyzed, 2 moles of alcohol react?B
30Formation of Acetals Addition of R-OH acid catalyzed, 2 moles of alcohol reactDraw the HemiB
31Formation of AcetalsAcetal reaction in equilibriumB