Chapter 14 Ketones, and Chiral Molecules Lecture Presentation Chapter 14 Ketones, and Chiral Molecules Karen C. Timberlake

Chapter 14 Aldehydes, Ketones, and Chiral Molecules A dermatology nurse performs many duties for the dermatologist, including treating skin conditions, assisting in surgeries, performing biopsies and excisions, writing prescriptions, freezing skin lesions, and screening patients for skin cancer. To become a dermatology nurse, you first become a nurse or physician assistant and then specialize in dermatology. General, Organic, and Biological Chemistry: Structures of Life, 5/e Karen C. Timberlake © 2016 Pearson Education, Inc.

Chapter 14 Readiness Core Chemistry Skills Naming and Drawing Alkanes (12.2) Naming Alcohols and Phenols (13.1) Writing Equations for the Oxidation of Alcohols (13.4)

14.1 Aldehydes and Ketones Formaldehyde is the simplest aldehyde. It is a colorless gas with a pungent odor. An aqueous solution called formalin, which contains 40% formaldehyde, is used as a germicide and to preserve biological specimens. Learning Goal Identify compounds with carbonyl groups as aldehydes and ketones. Write the IUPAC and common names for aldehydes and ketones; draw their condensed or line-angle structural formulas.

Carbonyl Group A carbonyl group in an aldehyde is bonded to at least one H atom. a ketone is bonded to two carbon groups. Aldehydes and ketones contain a carbonyl group that consists of a carbon–oxygen double bond with two groups of atoms attached to the carbon at angles of 120°.

Carbonyl Polarity The oxygen atom with two lone pairs of electrons is much more electronegative than the carbon atom. The carbonyl group has a strong dipole with a partial negative charge on the oxygen and a partial positive charge on the carbon. The polarity of the carbonyl group strongly influences the physical and chemical properties of aldehydes and ketones. δ− δ+

Naming Aldehydes In the IUPAC system, an aldehyde is named by replacing the e of the corresponding alkane name with al. no number is needed for the aldehyde group because it always appears at the end of the chain. aldehydes with carbon chains of one to four carbons are often referred to by their common names, which end in aldehyde. Core Chemistry Skill Naming Aldehydes and Ketones

Naming Aldehydes The IUPAC system names the aldehyde of benzene as benzaldehyde.

Guide to Naming Aldehydes

Study Check Give the IUPAC name for the following aldehyde:

Solution Give the IUPAC name for the following aldehyde: STEP 1 Name the longest carbon chain by replacing the e in the alkane name with al. ANALYZE Given Need THE condensed structural IUPAC name PROBLEM formula of aldehyde

Solution Give the IUPAC name for the following aldehyde: STEP 2 Name and number any substituents by counting the carbonyl group as carbon 1.

Naming Ketones To name ketones using common names, the alkyl groups bonded to the carbonyl group are named as substituents. the substituents are listed alphabetically, followed by ketone. Acetone, another name for propanone, has been retained by the IUPAC system. Propanone (dimethyl ketone, acetone)

Naming Ketones In the IUPAC system, the name of a ketone is obtained by replacing the e in the alkane name with one. chains with five carbon atoms or more are numbered from the end nearer the carbonyl group.

Naming Cyclic Ketones For cyclic ketones, the prefix cyclo is used in front of the ketone name. any substituent is located by numbering the ring starting with the carbonyl carbon as carbon 1. the ring is numbered in the direction to give substituents the lowest possible numbers.

Guide to Naming Ketones

Study Check Give the IUPAC name for the following ketone:

Solution Give the IUPAC name for the following ketone: STEP 1 Name the longest carbon chain by replacing the e in the alkane name with one. ANALYZE Given Need THE condensed structural IUPAC name PROBLEM formula of ketone

Solution Give the IUPAC name for the following ketone: STEP 2 Number the carbon chain starting from the end nearer the carbonyl group and indicate it location.

Solution Give the IUPAC name for the following ketone: STEP 3 Name and number any substituents on the carbon chain.

Naming Compounds: Two Functional Groups According to IUPAC rules for nomenclature, the more oxidized group will take priority in naming a compound with more than one functional group. Table 14.1 lists the priorities for the functional groups we have studied and the names of the functional groups as substituents.

Naming Compounds: Two Functional Groups The functional group that is highest on the list is named as the compound, and any group lower on the list is named as a substituent. Examples are given for naming an alcohol, a ketone, and an aldehyde.

Chemistry Link to Health: Important Aldehydes and Ketones Formalin, a 40% formaldehyde aqueous solution, is used as a germicide and to preserve biological specimens. is used in industry as a reactant in the synthesis of polymers used to make fabrics, insulation materials, carpeting, pressed wood products such as plywood, and plastics for kitchen counters. Exposure to fumes can irritate the eyes, nose, and upper respiratory tract and cause skin rashes, headaches, dizziness, and general fatigue.

Chemistry Link to Health: Important Aldehydes and Ketones The simplest ketone, known as acetone or propanone (dimethyl ketone), is a colorless liquid with a mild odor that has wide use as a solvent in cleaning fluids, paint and nail polish removers, and rubber cement. In the body, acetone may be produced in uncontrolled diabetes, fasting, and high-protein diets when large amounts of fats are metabolized for energy.

Chemistry Link to Health: Important Aldehydes and Ketones Several naturally occurring aromatic aldehydes are used to flavor food and as fragrances in perfumes. Benzaldehyde is found in almonds. Vanillin is found in vanilla beans. Cinnamaldehyde is found in cinnamon.

Study Check Identify the following compounds as either an aldehyde or a ketone: A. CH3—CH2—CH2—COH B. CH3—CH2—CO—CH2—CH2—CH3 C. D.

Study Check Identify the following compounds as either an aldehyde or a ketone: A. CH3—CH2—CH2—COH aldehyde B. CH3—CH2—CO—CH2—CH2—CH3 ketone C. ketone D. aldehyde

Study Check Give the IUPAC name of each of the following aldehydes: A. B. CH3—CH—CH2—CH2—CHO Cl

Solution Give the IUPAC name of each of the following aldehydes: A. 4-chloropentanal B. 2-ethylbenzaldehyde CH3—CH—CH2—CH2—CHO Cl

Study Check Give the IUPAC name of the following ketone:

Solution Give the IUPAC name of the following ketone: 3-ethyl-1-cyclopentanone

Study Check Name each of the following: A. B. C.

Solution Name each of the following: A. pentanal B. 2-butanone C. 3,3-dimethylbutanal