Aldehydes and Ketones

Drill Draw & name 5 isomers of: C 3 H 5 OF

Aldehydes Organic compounds with carbonyl groups on the end carbon

Aldehydes O R-C H

Ketones Organic compounds with carbonyl groups within carbon chains

Ketones O R-C-R

Common Aldehydes

Formaldehyde O H-C H Methanal

Acetaldehyde O CH 3 -C H Ethanal

Propionaldehyde O CH 3 -CH 2 -C H Propanal

Butyraldehyde O CH 3 CH 2 CH 2 C H Butanal

Benzaldehyde O C H Almond Extract

Cinnamaldehyde O

all-trans-retinal C=O H

all-trans-retinol

4-hydroxy-3-methoxy benzaldehyde Vanillin C O H HO H 3 C-O

Draw: acetaldehyde & benzaldehyde

Common Ketones

Acetone O CH 3 -C CH 3 Propanone

Methyl ethyl ketone O CH 3 CH 2 C CH 3 Butanone

Cyclohexanone O

Benzophenone C O Diphenylmethanone

Muscone O

General Properties

Polarity Alcohols > aldehydes Aldehydes > ketones

Solubility in Water Alcohols > aldehydes Aldehydes > ketones

Boiling Points Alcohols > aldehydes Aldehydes > ketones

Melting Points Alcohols > aldehydes Aldehydes > ketones

Oxidation State Alcohols > hydrocarbons Aldehydes > alcohols Acids > aldehydes

Show all the oxidation steps in converting butane to 3-butenoic acid

Energy State Alcohols < hydrocarbons Aldehydes < alcohols Acids < aldehydes

Chm PE Gradient Methane:CH 4 Methanol:CH 3 OH MethanalCH 2 O Methanoic A: HCOOH

Chm PE Gradient Reduced Compounds > Less reduced compounds > Oxidized compounds

Determine MP order CH 3 -CH 3 CH 3 -CH 2 OH CH 3 -CHO CH 3 -COOH

Drill: Draw & name 5 isomers of: C 3 H 9 NO

Making Aldehydes & Ketones

Oxidation of primary alcohols Making Aldehydes

To oxidize alcohols, Hs must be removed from the OH & the adjacent carbon Making Aldehydes

OH R-C-H H ox

Making Aldehydes OH R-C-H H ox

Making Aldehydes OH O R-C-H R-C H H ox

Common Oxidizing Agents Cr 2 O 7 -2 MnO 4 -1

Examples: K 2 Cr 2 O 7 KMnO 4

Oxidation of secondary alcohols Making Ketones

OH R-C-R ox H

Making Ketones OH O R-C-R R-C R ox H

t-Alcohol Ox OH R-C-R R ox

t-Alcohol Ox OH R-C-R NR ox R

Name reactants & predict & name products H 3 C-OH K 2 Cr 2 O 7 H 2 SO 4

Formaldehyde H C=O H Methanal

Name reactants & predict & name products H 2 C-OH H 3 C K 2 Cr 2 O 7 H 2 SO 4

Acetaldehyde H C=O H 3 C Ethanal

Name reactants & predict & name products OH H 3 C-CH-CH 3 K 2 Cr 2 O 7 H 2 SO 4

Acetone H 3 C C=O H 3 C Propanone

Name reactants & predict & name products K 2 Cr 2 O 7 H 2 SO 4 OH

Cyclohexanone O

Name reactants & predict & name products K 2 Cr 2 O 7 H 2 SO 4 CH 2 OH

Benzaldehyde CHO

Aldehyde Detection Reactions

Detecting Aldehydes Tollen’s Test Benedict’s & Fehling’s Test Both distinguish aldehydes from ketones

Tollen’s Reagent AgNO 3 Ag + + NO 3 - Ag NH 3 [Ag(NH 3 ) 2 ] %

Tollen’s Test O R-C-H + 2[Ag(NH 3 ) 2 ] + + 2OH - O NH 4 + R-CO - + 2Ag (s) +3NH 3 + H 2 O

Benedict’s Reagent CuSO 4 Cu +2 + SO 4 -2 NaOH Na + + OH % Fehling’s Reagent

Benedict’s Test O R-C-H + 2 Cu OH - O R-C-O - + Cu 2 O (s) + 3H 2 O

 -Hydroxy Ketones HO O R-C-C H R Yield positive results in both tests

Drill: Draw  -hydroxy- propanaldehyde

Carbonyl Addition Reactions

Carbonyl Addition Rxns with water O C + H-OH C HO OH Hydrate

Carbonyl Addition Rxns O C + H-OH C HO OH Chloral Hydrate H Cl 3 C Chloral or trichloroacetaldehyde H CCl 3

Carbonyl Addition Rxns O C + H-OH H H Methanal

Carbonyl Addition Rxns O C + H-OH C HO OH Methanediol H HH H

Carbonyl Addition Rxns with alcohols O C + R-OH C RO OH

Example O C + OH H 3 C H

C H 3 C H HO O

Drill: Draw & name 4 isomers C 5 H 10 O that are either aldehydes or ketones:

Hemiketal Formation O C + R 3 -OH C R 3 -OOH R 1 R 2 Hemiketal

Name reactants & draw products O C + CH 3 -OH H 3 C CH 3

O C + CH 3 -OH C H 3 C-OOH H 3 C CH 3 CH 3 Hemiketal

Hemiacetal Formation O C + R 3 -OH C R 3 -OOH R 1 H Hemiacetal

Hemiacetal Formation O C + R 3 -OH C R 3 -OOH H 3 C H CH 3 H Hemiacetal

Hemiacetal Formation O C + R 3 -OH C R 3 -OOH H 3 C H CH 3 H Hemiacetal

Draw the reactants & products when water is added to 2-butanone

Draw the reactants & products when methanol is added to acetone

Full Acetals & Ketals The second addition of an alcohol to either hemi- acetals or ketals will produce full each

Uses of Aldehydes & Ketones

1)1-propanol + KMnO 4 2)2-propanol + K 2 Cr 2 O 4 3)2-methyl-2-propanol + K 2 Cr 2 O 4 4) cyclohexanone + water 5)benzaldehyde + water 6)formaldehyde + 1-butanol 7)acetone + phenol 8) 5-hydroxypentanaldehyde (addition)

1)ethanol + KMnO 4 2)2-pentanol + K 2 Cr 2 O 7 3)t-butanol+ K 2 Cr 2 O 7 4) acetone + water 5)formaldehyde + water 6)propanaldehyde + methanol 7) 2-butanone + phenol 8) 4-hydroxybutanaldehyde (addition)

Name the following: OH H O

Review

Name the following: O H OH

Draw the following: 3-ethyl-6-methyl- 2-phenoxy-1- sulfhydryl-octa- 4,5-dione

Oxidation of each with KMnO 4 or K 2 Cr 2 O 7 : 1-butanol 2-butanol 2-methyl-2-propanol

Carbonyl Addition Rxns: 2-butanone + water Propanaldehyde + water Acetone + methanol Acetaldehyde + ethanol

Draw the reactants & products when 5- hydroxypentanal reacts with itself

Draw & name 3 isomers of C 4 H 8 O containing carbonyls

Draw & name 10 isomers of C 4 H 8 O