Chapter 23 Functional Groups 23.3 Carbonyl Compounds 23.1 Introduction to Functional Groups 23.2 Alcohols, Ethers, and Amines 23.3 Carbonyl Compounds 23.4 Polymers Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What gives a banana its characteristic smell? CHEMISTRY & YOU What gives a banana its characteristic smell? Many organic molecules have pleasant aromas. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What structural characteristic do an aldehyde and a ketone share? Aldehydes and Ketones Aldehydes and Ketones What structural characteristic do an aldehyde and a ketone share? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Aldehydes and Ketones An oxygen atom can also be bonded to a single carbon atom by a double covalent bond. A carbonyl group is a functional group with the general structure C O. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

The C O functional group is present in aldehydes and ketones. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Aldehydes and Ketones An aldehyde is an organic compound in which the carbon of the carbonyl group is joined to at least one hydrogen. The general formula of an aldehyde is RCHO. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Aldehydes and Ketones A ketone is an organic compound in which the carbon of the carbonyl group is joined to two other carbons. The general formula of a ketone is RCOR. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

The IUPAC system may be used for naming aldehydes and ketones. First identify the longest carbon chain that contains the carbonyl group. Replace the -e ending of the parent structure with -al to designate an aldehyde. In the IUPAC system, the continuous chain aldehydes are named methanal, ethanal, propanal, butanal, and so forth. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

The IUPAC system may be used for naming aldehydes and ketones. Ketones are named by changing the ending of the longest continuous carbon that contains the carbonyl group from -e to -one. If the carbonyl group of a ketone could occur at more than one place on the chain, then its position is designated by the lowest possible number. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

IUPAC name (common name) Interpret Data Some Common Aldehydes IUPAC name (common name) Structural formula Ball-and-stick model Methanal (formaldehyde) Ethanal (acetaldehyde) Benzaldehyde (benzaldehyde) Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

IUPAC name (common name) Interpret Data Some Common Ketones IUPAC name (common name) Structural formula Ball-and-stick model Propanone (acetone) Diphenylmethanone (benzophenone) Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Uses of Aldehydes and Ketones The simplest aldehyde is methanal (HCHO), also called formaldehyde. Its greatest use is in the manufacture of synthetic resins. A 40% aqueous solution of methanal, known as formalin, can be used to preserve biological specimens. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Uses of Aldehydes and Ketones The most common industrial ketone is propanone, also called acetone. Propanone is used in industry as a solvent for resins, plastics, and varnishes. Many nail-polish removers contain propanone as well. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Uses of Aldehydes and Ketones A wide variety of aldehydes and ketones have been isolated from plants and animals. Many have fragrant odors. Benzaldehyde is also known as oil of bitter almond because it is largely responsible for the taste and aroma of almonds. Many flavoring agents, including vanilla bean extract and cinnamon sticks, contain aromatic aldehydes. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Properties of Aldehydes and Ketones Aldehydes and ketones cannot form intermolecular hydrogen bonds because they lack —OH and —NH groups. They have boiling points that are lower than those of corresponding alcohols. Aldehydes and ketones can attract each other, however, through polar-polar interactions of their carbonyl groups. Their boiling points are higher than those of the corresponding alkanes. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Some Organic Compounds with Three Carbons Interpret Data Some Organic Compounds with Three Carbons Compound Formula Boiling Point (°C) Primary intermolecular interactions Propane CH3CH2CH3 –42 Dispersion forces Propanal CH3CH2CHO 49 Polar-polar interactions Propanone CH3COCH3 56 1-Propanol CH3CH2CH2OH 97 Hydrogen bonding Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Properties of Aldehydes and Ketones Aldehydes and ketones can form weak hydrogen bonds between the carbonyl oxygen and the hydrogen atoms of water. The lower members of the series—up to three carbons—are soluble in water in all proportions. As the length of the hydrocarbon chain increases above four, however, water solubility decreases. As might be expected, all aldehydes and ketones are soluble in nonpolar solvents. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Why do aldehydes and ketones have similar properties? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Why do aldehydes and ketones have similar properties? Aldehydes and ketones have similar properties because each contains a C O functional group. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What is the general formula of a carboxylic acid? Carboxylic Acids Carboxylic Acids What is the general formula of a carboxylic acid? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

It can be written as —COOH or —CO2H. Carboxylic Acids A carboxyl group is a functional group that consists of a carbonyl group attached to a hydroxy group. It can be written as —COOH or —CO2H. A carboxylic acid is an organic compound with a carboxyl group. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

The general formula of a carboxylic acid is RCOOH. Carboxylic Acids The general formula of a carboxylic acid is RCOOH. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Carboxylic Acids Carboxylic acids are considered weak acids because they ionize weakly in solution. In water, they can lose a hydrogen ion and form a carboxylate ion, as shown in the following reaction. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Carboxylic Acids In the IUPAC system, carboxylic acids are named by replacing the -e ending of the parent structure with the ending -oic acid. Remember, the parent hydrocarbon of a carboxylic acid is the longest continuous carbon chain containing the carboxyl group. The carboxylic acid CH3COOH is named ethanoic acid. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Some Saturated Aliphatic Carboxylic Acids Interpret Data Some Saturated Aliphatic Carboxylic Acids Molecular formula Carbon atoms IUPAC name Common name Melting point (°C) HCOOH 1 Methanoic acid Formic acid 8 CH3COOH 2 Ethanoic acid Acetic acid 17 CH3CH2COOH 3 Propanoic acid Propionic acid –22 CH3(CH2)2COOH 4 Butanoic acid Butyric acid –6 CH3(CH2)4COOH 6 Hexanoic acid Caproic acid –3 CH3(CH2)6COOH Octanoic acid Caprylic acid 16 CH3(CH2)8COOH 10 Decanoic acid Capric acid 31 CH3(CH2)10COOH 12 Dodecanoic acid Lauric acid 44 CH3(CH2)12COOH 14 Tetradecanoic acid Myristic acid 58 CH3(CH2)14COOH Hexadecanoic acid Palmitic acid 63 CH3(CH2)16COOH 18 Octadecanoic acid Stearic acid 70 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Carboxylic Acids Lemons and limes contain citric acid, a carboxylic acid that gives citrus fruits their sour flavor. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Carboxylic Acids Many carboxylic acids were first isolated from fats and are called fatty acids. Propionic acid, the three-carbon acid, literally means first fatty acid. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Like alcohols, carboxylic acids form intermolecular hydrogen bonds. Thus, carboxylic acids have higher boiling and melting points than other compounds of similar molar mass. The low-molar-mass members of the aliphatic carboxylic acid series are colorless, volatile liquids. The higher members of the series are nonvolatile, waxy solids with low melting points. All aromatic carboxylic acids are solids at room temperature. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Carboxylic Acids The carboxyl group in carboxylic acids is polar and readily forms hydrogen bonds with water molecules. Methanoic, ethanoic, propanoic, and butanoic acids are completely soluble in water. After four carbons, however, the solubility drops sharply. Most carboxylic acids are also soluble in organic solvents such as ethanol or propanone. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What is a fatty acid? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

A fatty acid is a carboxylic acid that was first isolated from fats. What is a fatty acid? A fatty acid is a carboxylic acid that was first isolated from fats. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Why is dehydrogenation classified as an oxidation reaction? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions The classes of organic compounds you have just studied—aldehydes, ketones, and carboxylic acids—are related by oxidation and reduction reactions. Oxidation is the gain of oxygen, loss of hydrogen, or loss of electrons. Reduction is the loss of oxygen, gain of hydrogen, or gain of electrons. One does not occur without the other. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions In organic chemistry, the number of oxygen atoms and hydrogen atoms attached to carbon indicates the degree of oxidation of a compound. The fewer hydrogens on a carbon-carbon bond, the more oxidized the bond. Thus, a triple bond is more oxidized than a double bond, which is more oxidized than a single bond. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions The loss of a molecule of hydrogen from an organic molecule is called a dehydrogenation reaction. It is the opposite of a hydrogenation reaction. Strong heating and a catalyst are usually needed to make dehydrogenation reactions occur. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Dehydrogenation is an oxidation reaction because the loss of each molecule of hydrogen involves the loss of two electrons from the organic molecule. The remaining carbon electrons pair to make a second or third bond. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Oxidation in organic chemistry also involves the number and degree of oxidation of oxygen atoms attached to the carbon atom. Methane, a saturated hydrocarbon, can be oxidized in steps to carbon dioxide. Methane is oxidized to methanol, then to methanal, then to methanoic acid, and finally to carbon dioxide. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions The more reduced a carbon compound is, the more energy it can release upon its complete oxidation to carbon dioxide. The oxidation of organic compounds is exothermic. The energy-releasing properties of oxidation reactions are extremely important for the production of energy in living systems. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Primary alcohols can be oxidized to aldehydes. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Secondary alcohols can be oxidized to ketones by warming them with acidified potassium dichromate (K2Cr2O7). Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Tertiary alcohols, however, cannot be oxidized because there is no hydrogen atom present on the carbon atom attached to the hydroxy group. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Aldehydes are so easily oxidized that it is difficult to prevent further oxidation to carboxylic acids. Further oxidation is avoided by removing aldehydes from the reaction mixture as they are formed. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Oxidation-Reduction Reactions Tests for aldehydes make use of the ease with which these compounds are oxidized. Benedict’s and Fehling’s reagents are deep-blue alkaline solutions of copper(II) sulfate. When an aldehyde is oxidized with Benedict’s or Fehling’s reagent, a red precipitate of copper(I) oxide is formed. The aldehyde is oxidized to its acid, and copper (II) ions are reduced to copper(I) ions. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What hydrocarbon can be oxidized to form aldehydes What hydrocarbon can be oxidized to form aldehydes? What hydrocarbon can be oxidized to ketones? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What hydrocarbon can be oxidized to form aldehydes What hydrocarbon can be oxidized to form aldehydes? What hydrocarbon can be oxidized to ketones? A primary alcohol can be oxidized to an aldehyde. A secondary alcohol can be oxidized to a ketone. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What is the general formula of an ester? Esters Esters What is the general formula of an ester? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters Esters are probably the most pleasant and delicious organic compounds one can study. Many esters have pleasant, fruity odors. Esters give blueberries, pineapples, apples, pears, bananas, and many other fruits their characteristic aromas. They also give many perfumes their fragrances. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters An ester is an organic compound in which the —OH of the carboxyl group has been replaced by an —OR from an alcohol. Esters contain a carbonyl group and an ether link to the carbonyl carbon. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

The general formula of an ester is RCOOR. Esters The general formula of an ester is RCOOR. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

CHEMISTRY & YOU The smell of strawberries is largely due to benzyl acetate. The smell of almonds is largely due to benzaldehyde. How are the general formulas of these compounds similar? How are they different? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

CHEMISTRY & YOU The smell of strawberries is largely due to benzyl acetate. The smell of almonds is largely due to benzaldehyde. How are the general formulas of these compounds similar? How are they different? Benzyl acetate and benzaldehyde each contain a benzene ring. Benzyl acetate contains an ester group, while benzaldehyde contains an aldehyde group. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters Although ester molecules are polar, they cannot form hydrogen bonds with one another. They do not contain hydrogen attached to oxygen or another electronegative atom. As a result, only weak attractions hold ester molecules to one another. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters Although ester molecules are polar, they cannot form hydrogen bonds with one another. They do not contain hydrogen attached to oxygen or another electronegative atom. As a result, only weak attractions hold ester molecules to one another. Esters have much lower boiling points than carboxylic acids. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters Although ester molecules are polar, they cannot form hydrogen bonds with one another. The low-molar-mass esters are somewhat soluble in water, but esters containing more than four or five carbons have very limited solubility. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters may be prepared from a carboxylic acid and an alcohol. The process is called esterification. The reactants, usually a carboxylic acid and a primary or secondary alcohol, are heated with an acid as a catalyst. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Esters If an ester is heated with water for several hours, usually very little happens. In strong acid or base solutions, however, the ester breaks down. An ester is hydrolyzed by the addition of water to produce a carboxylic acid and an alcohol. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Hydroxide ions also promote this reaction. Esters Hydroxide ions also promote this reaction. Because many esters do not dissolve in water, a solvent such as ethanol is added to make the solution homogeneous. The reaction mixture is usually heated. All of the ester is converted to products. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

If the reaction mixture is acidified, the carboxylic acid forms. Esters If the reaction mixture is acidified, the carboxylic acid forms. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What are reactants in an esterification reaction? What are the products? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

What are reactants in an esterification reaction? What are the products? The reactants in an esterification reaction are a carboxylic acid and an alcohol. The products are an ester and water. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

The C O functional group is present in aldehydes and ketones. Key Concepts The C O functional group is present in aldehydes and ketones. The general formula of a carboxylic acid is RCOOH. Dehydrogenation is an oxidation reaction because the loss of each molecule of hydrogen involves the loss of two electrons from the organic molecule. The general formula of an ester is RCOOR. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Glossary Terms carbonyl group: a functional group having a carbon atom and an oxygen atom joined by a double bond; it is found in aldehydes, ketones, esters, and amides aldehyde: an organic compound in which the carbon of the carbonyl group is joined to at least one hydrogen; the general formula is RCHO ketone: an organic compound in which the carbon of the carbonyl group is joined to two other carbons; the general formula is RCOR Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Glossary Terms carboxyl group: a functional group consisting of a carbonyl group attached to a hydroxyl group; it is found in carboxylic acids carboxylic acid: an organic acid containing a carboxyl group; the general formula is RCOOH fatty acid: the name given to continuous-chain carboxylic acids that were first isolated from fats Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

dehydrogenation reaction: a reaction in which hydrogen is lost Glossary Terms dehydrogenation reaction: a reaction in which hydrogen is lost ester: a derivative of a carboxylic acid in which the —OH of the carboxyl group has been replaced by the —OR from an alcohol; the general formula is RCOOR Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

Carbon Chemistry and Reactions BIG IDEA Carbon Chemistry and Reactions Chemical reactions can be used to change the structure of organic molecules, often by introducing a new functional group. Oxidation-reduction reactions are commonly used in organic chemistry. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.

END OF 23.3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved.