Chemistry 121(001) Winter 2015 Introduction to Organic Chemistry and Biochemistry Instructor Dr. Upali Siriwardane (Ph.D. Ohio State) E-mail: upali@latech.edu Office: 311 Carson Taylor Hall ; Phone: 318-257-4941; Office Hours: MTW 8:00 - 10:00 am; ThF 9:00 - 10:00 am 1:00 - 2:00 pm. December 19, 2014: Test 1 (Chapters 12-13) January 26 , 2015: Test 2 (Chapters 14-16) February 13, 2015: Test 3 (Chapters 17-19) March 2, 2015: Test 4 (Chapters 20-22) March 3 , 2015: Make Up Exam: Chapters 12-22) Bring Scantron Sheet 882-E

Chapter 15: Aldehyde and Ketones 15.1 The Carbonyl Group, 469 15.2 Compounds Containing a Carbonyl Group, 470 15.3 The Aldehyde and Ketone Functional Groups, 471 15.4 Nomenclature for Aldehydes, 472 15.5 Nomenclature for Ketones, 474 15.6 Isomerism for Aldehydes and Ketones, 476 15.7 Selected Common Aldehydes and Ketones, 476 15.8 Physical Properties of Aldehydes and Ketones, 479 15.9 Preparation of Aldehydes and Ketones, 481 15.10 Oxidation and Reduction of Aldehydes and Ketones, 482 15.11 Reaction of Aldehydes and Ketones with Alcohols, 486 15.12 Formaldehyde-Based Polymers, 491 15.13 Sulfur-Containing Carbonyl Groups, 492

Carbonyl Group

Simplest Aldehyde

Common Names of Aldehyde and Ketones Aldehydes: Fomaldehyde: HCHO Acetaldehyde: CH3CHO Propionaldehyde: CH3CH2CHO Butyraldehyde: CH3CH2CH2CHO Valeraldehyde: CH3CH2CH2CH2CHO Ketones: Acetone: CH3COCH3 Methyl ethyl ketone CH3CH2COCH3 Butyl propyl ketone CH3CH2CH2CH2COCH2CH2CH3

IUPAC Nomenclature of Aldehyde and Ketones The IUPAC system deals with functional groups two different ways. Modification of the hydrocarbon name to indicate the presence of a functional group. aldehyde, -CHO use -al ending. Ketones -RCOR’ use -one ending.

IUPAC Nomenclature of Aldehyde and Ketones The IUPAC system deals with functional groups two different ways. Modification of the hydrocarbon name to indicate the presence of a functional group. aldehyde, -CHO use -al ending. Ketones -RCOR’ use -one ending.

Example C - C - C - C - CHO C - C - C - C - CO-C-C Base contains 5 carbon - aldehyde name is pentane - remove -e and add -al C - C - C - C - CO-C-C Base contains 7 carbon - aldehyde name is heptane - remove -e and add -one 3-heptanone

Physical Properties of Aldehydes and ketones Aldehyde and ketones can only make dipole-dipole attraction. BP and MP are lower than alcohols , higher than hydrocarbons and ether with comparable carbon numbers

Bonding Characteristics of Aldehydes Ketones Both aldehydes and ketones contain a carbonyl functional group. A carbonyl group is an carbon atom double-bonded to an oxygen atom. The structural representation for a carbonyl group is Carbon-oxygen (C=O) and carbon-carbon (C=C) double bonds differ in a major way. A carbon oxygen double bond is more polar

Physical properties of aldehydes and ketones.

Nomenclature

Name the Aldehyde 2,4-dimethylpentanal

1. Assign the type of organic compound with following general condensed (structural formula.

2. Names (common/IUPAC)of following aldehydes and ketones. a) ____________ b) _______________ c) __________________ d) ____________ e) _______________ f) __________________ g) ____________ h) __________________

Nomenclature

3. Draw the condensed formula of following aldehydes and ketones: acetaldehyde/ ethanal b) ethyl methyl ketone   c) 3-methyl-2- pentanone d) isopropyl methyl e) 2-methylbutanal f) 5-methyl-3- hexanone g) benzophenone h) acetophenone

Addition reactions of als & ones Hemiacetal or hemiketal formation

Hemiacetal form of cyclic sugars

4. Identify each of the following compounds as a hemiacetal, hemiketal, acetal, or ketal: a) ____________ b) _______________ c) __________________ d) ____________ e) _______________ f) __________________

Important Aldehydes Methanal or formaldehyde Ethanal or acetaldehyde 2-Propanone or acetone 2-Butanone or methyl ethyl ketone Oil of almonds or benzaldehyde Oil of Cinnamon or cinnamaldehyde Oil of vanilla beans or vanillin Mushroom flavoring or 2-octanone Oil of lemongrass or citral:

Bakelite

Preparation of Aldehydes: Partial oxidation of primary alcohols with H2CrO4:

Preapration of ketones: Oxidation of secondary alcohols with KMnO4, or H2CrO4

Oxidation of alcohol

Oxidation of Alcohols to oxidize a 1° alcohol to an aldehyde, use PCC PCC oxidation of geraniol gives geranial Tertiary alcohols are not oxidized by either of these reagents; they are resistant to oxidation

Oxidation of alcohol

5) Which alcohol would you oxidize to produce each of the following compounds? b) c) d)

6) Preparation of adehydes and ketones a) Control oxidation of 1ry alcohol b) Complete oxidation of 1ry alcohol

6) Preparation of adehydes and ketones c) Oxidation of 2ry alcohol d) Oxidation of 3ry alcohol No Reaction

Chemical Reactions of Aldehydes and Ketone 1) Combustion: Alkenes are very flammable and the combustion products are carbon dioxide and water. 2) Addition Reactions: Atoms or group of atoms are added to each a carbon oxygen double bond. Two different reactants are involved. a) hemi-acetal or hemi-ketal formation: Addition of Alcohols: -OR group of the R-OH is added to the C atom and H of the ROH is added to O atom. b) Aacetal or ketal formation : Another or second ROH is reacted in a substitution reaction to replace the H atom of the -OH group of the hemi-acetal or hemi-ketal and water molecule is produced. O: both reactants (H-X (X= Cl, OH)) and the alkene need to be asymmetric 3) Oxidation Reactions: only aldehydes are oxidized to carboxylic acids. 4) Reduction Reactions: both aldehydes and ketones are reduced to alcohols by taking H from the reducing agents.

Chemical Reactions of Aldehydes and Ketone a) hemi-acetal or hemi-ketal formation: Addition of Alcohols: -OR group of the R-OH is added to the C atom and H of the ROH is added to O atom. b) Aacetal or ketal formation : Another or second ROH is reacted in a substitution reaction to replace the H atom of the -OH group of the hemi-acetal or hemi-ketal and water molecule is produced. O: both reactants (H-X (X= Cl, OH)) and the alkene need to be asymmetric

Reduction of als & ones compounds to alcohols:

Redox Reactions Reduction Reactions: both aldehydes and ketones are reduced to alcohols by taking H from the reducing agents. LiAlH4 NaBH4 H2/Ni or Pt catalysts Oxidation Reactions: only aldehydes are oxidized to carboxylic acids. Jone’s Reagent AgNO3/NH4OH (silver mirror test) CuSO4/Na2CO3/Citrate (Benedict’s reagent)

Aldehyde and Ketone Reduction: To alcohols

7) Complete the following reductions of aldehyde and ketones and identify the type of alcohols (1ry, 2ry and 3ry) produced. d)

Reduction of als & ones compounds to alcohols:

Addition reactions of als & ones Hemiacetal or hemiketal formation

Addition reactions of als & ones Hemiacetal or hemiketal formation

Hemiacetal form of cyclic sugars

Formation of Acetals and Ketals.

8) Complete the following formation reactions hemiacetal, hemiketal, acetal, or ketal:

Redox Reactions Reduction Reactions: both aldehydes and ketones are reduced to alcohols by taking H from the reducing agents. LiAlH4 NaBH4 H2/Ni or Pt catalysts Oxidation Reactions: only aldehydes are oxidized to carboxylic acids. Jone’s Reagent AgNO3/NH4OH (silver mirror test) CuSO4/Na2CO3/Citrate (Benedict’s reagent)

Chemical Reactions Oxidation of aldehyde. Benedict's Test for aldehydes:

Test for Urine Glucose: Benedict’s Test

Tollen's Test: Oxidation of aldehyde. The commercial manufacture of silver mirrors uses a similar process.

9) Complete reactions of following aldehydes and ketones Tollen’s Reagent: Silver mirror test: Benedict's test:

9) Complete reactions of following aldehydes c) Oxidation of aldehyde and ketones c) Oxidation of aldehyde d) Cyclic hemi-acetal formation

Addition of HCN and H2O

Aldol Condensation In biological systems this reaction is catalysed by an enzyme named aldolase.

Keto & Enol tautomers keto form enol from

Keto & Enol tautomers in sugars aldehyde enol ketone

Addition reactions of als & ones Hemiacetal or hemiketal formation

Formation of Acetals and Ketals.

Hemiacetal form of cyclic sugars