15: Organic Acids and Bases and Some of Their Derivatives
- Page ID
- 15934
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Organic acids have been known for ages. Prehistoric people likely made acetic acid when their fermentation reactions went awry and produced vinegar instead of wine. The Sumerians (2900–1800 BCE) used vinegar as a condiment, a preservative, an antibiotic, and a detergent. Citric acid was discovered by an Islamic alchemist, Jabir Ibn Hayyan (also known as Geber), in the 8th century, and crystalline citric acid was first isolated from lemon juice in 1784 by the Swedish chemist Carl Wilhelm Scheele. Medieval scholars in Europe were aware that the crisp, tart flavor of citrus fruits is caused by citric acid. Naturalists of the 17th century knew that the sting of a red ant’s bite was due to an organic acid that the ant injected into the wound. The acetic acid of vinegar, the formic acid of red ants, and the citric acid of fruits all belong to the same family of compounds—carboxylic acids. Soaps are salts of long-chain carboxylic acids. Prehistoric people also knew about organic bases—by smell if not by name; amines are the organic bases produced when animal tissue decays. The organic compounds that we consider in this chapter are organic acids and bases. We will also consider two derivatives of carboxylic acids: esters and amides. An ester is derived from a carboxylic acid and an alcohol. Fats and oils are esters, as are many important fragrances and flavors. An amide is derived from a carboxylic acid and either ammonia or an amine. Proteins, often called “the stuff of life,” are polyamides.
- 15.0: Prelude to Organic Acids and Bases and Some of Their Derivatives
- This page discusses the historical usage of organic acids, including acetic and citric acid. Acetic acid was created through ancient fermentation, while the Sumerians employed vinegar. Citric acid was first discovered in the 8th century and isolated in 1784. The recognition of organic acids and bases emerged through natural phenomena, such as the sting of red ants, and carboxylic acids are noted as a prevalent group, including those in soaps.
- 15.1: Carboxylic Acids - Structures and Names
- This page discusses carboxylic acids, prevalent in nature and found in various products. They have common names based on their sources, like formic acid from ants and acetic acid from vinegar. The IUPAC naming system describes their structure by modifying the longest carbon chain with the suffix -oic and incorporating "acid." The placement of substituents is denoted using Greek letters or numerical designations. Examples highlighted include formic, acetic, propionic, and butyric acids.
- 15.2: The Formation of Carboxylic Acids
- This page discusses the formation of carboxylic acids through the oxidation of aldehydes or primary alcohols, specifically detailing the conversion of ethanol to acetaldehyde and then to acetic acid via an oxidizing agent. It also highlights the liver's role in this process, where enzymes facilitate the transformation of ethanol to acetic acid, which can subsequently oxidize to carbon dioxide and water.
- 15.3: Physical Properties of Carboxylic Acids
- This page discusses carboxylic acids, which are colorless liquids with strong odors, particularly those containing 5 to 10 carbon atoms. They have high boiling points due to hydrogen bonding and greater water solubility than alkanes and alcohols of similar molar mass. Acids with 1 to 4 carbon atoms are completely miscible with water, while solubility decreases with longer carbon chains. Their boiling points increase with molar mass, but melting points vary unpredictably.
- 15.4: Chemical Properties of Carboxylic Acids- Ionization and Neutralization
- This page discusses carboxylic acids as weak acids that partially ionize in water to form carboxylate anions. They react with bases, producing salts (with names ending in -ate) and occasionally carbon dioxide. Organic salts like sodium propionate and sodium benzoate are highlighted for their role as food preservatives, preventing microbial growth.
- 15.5: Esters - Structures and Names
- This page discusses esters, organic compounds with the formula RCOOR′ and a carbon-to-oxygen double bond. They are common in nature, imparting pleasant scents to fruits and flowers, and are utilized in perfumes and flavorings. Esters are named by placing the alkyl or aryl group name before the acid part while changing the -ic ending to -ate. Examples include methyl acetate and ethyl acetate. Knowledge of their structure and naming is crucial in organic chemistry.
- 15.6: Physical Properties of Esters
- This page discusses the characteristics of esters, highlighting their polar nature and inability to hydrogen bond with themselves, leading to lower boiling points than carboxylic acids. It notes their solubility in water, particularly for low molar mass esters, and their role as common solvents in applications like caffeine extraction and plasticizers. The page also mentions the variability in boiling points and aromas among different esters.
- 15.7: Preparation of Esters
- This page discusses the preparation of esters through esterification, where carboxylic acids react with alcohols, often using a mineral acid catalyst. An example provided is butyl acetate from acetic acid and 1-butanol. It also covers condensation polymerization, highlighting the reaction of a dicarboxylic acid with a diol to produce polyesters such as polyethylene terephthalate (PET), which is utilized in fabrics, beverage bottles, and medical applications.
- 15.8: Hydrolysis of Esters
- This page discusses the hydrolysis of esters, which involves replacing the alkoxy group with water. Acidic hydrolysis results in a carboxylic acid and alcohol, while basic hydrolysis (saponification) yields a carboxylate salt and alcohol, with the latter being irreversible. Key examples highlight the products formed, such as butyric acid and sodium acetate from different esters.
- 15.9: Esters of Phosphoric Acid
- This page discusses the importance of phosphate esters in biochemistry, noting their presence in all living cells where they serve as intermediates in energy transformation and as structural components of phospholipids and nucleic acids. It highlights ATP's role as a key molecule that releases energy through high-energy bonds for biological processes.
- 15.10: Amines - Structures and Names
- This page discusses the classification of amines as primary, secondary, or tertiary based on the number of carbon groups bonded to nitrogen. Naming involves specifying the attached alkyl groups followed by the suffix -amine, with special rules for aryl amines like aniline. It also covers the naming of ammonium ions, which reflects the alkyl groups attached to nitrogen. Understanding amine structure and nomenclature is crucial in organic chemistry.
- 15.11: Physical Properties of Amines
- This page explains that amines have higher boiling points than alkanes and ethers due to hydrogen bonding but lower than alcohols because of the electronegative nature of oxygen. Tertiary amines have boiling points similar to alkanes and ethers. Low molar mass amines are water-soluble due to their ability to hydrogen bond with water. Furthermore, amines possess unique odors, and some aromatic amines are toxic and carcinogenic.
- 15.12: Amines as Bases
- This page discusses the role of amines as bases that form soluble salts when reacting with acids. It highlights heterocyclic amines, which contain nitrogen in their cyclic structures, and their significance in medicine and biochemistry. Notably, many naturally occurring heterocyclic amines, called alkaloids, are pharmacologically active, including substances like caffeine, nicotine, and cocaine.
- 15.13: Amides- Structures and Names
- This page explains amides, highlighting their structure with nitrogen bonded to a carbonyl carbon. It distinguishes between simple amides (nitrogen bonded to hydrogen) and substituted amides (having alkyl/aryl groups). The amide linkage's stability is significant in proteins as peptide bonds. Amides are named by changing the -ic or -oic suffix of carboxylic acids to -amide, with examples demonstrating common and IUPAC names of amides from specific acids.
- 15.14: Physical Properties of Amides
- This page discusses amides, focusing on their properties such as boiling points, solubility in water, and structure. Most simple amides, except formamide, are solids and have higher boiling points than comparable alcohols. Amides with five or fewer carbon atoms are typically water-soluble, while those with more show limited solubility.
- 15.15: Formation of Amides
- This page discusses the formation of amides through the reaction of ammonia with carboxylic acids, emphasizing that this process is catalyzed by enzymes in living cells to form peptide bonds in proteins. It also notes the synthesis of polyamides from diacids and diamines, leading to the creation of materials like nylons, which have diverse applications. The main point is that amides can be prepared from carboxylic acids in combination with ammonia or amines.
- 15.16: Chemical Properties of Amides- Hydrolysis
- This page discusses the hydrolysis of amides, which typically resist hydrolysis in water but can be hydrolyzed in acidic or basic conditions, producing carboxylic acids and ammonia or amines, often catalyzed by enzymes in living cells.
- 15.S: Organic Acids and Bases and Some of Their Derivatives (Summary)
- This page discusses key organic compounds: carboxylic acids (weak acids with strong odors, derived from aldehydes and alcohols), esters (formed from carboxylic acids and alcohols, known for pleasant smells and lower boiling points), amines (nitrogen-containing compounds from ammonia), and amides (carbonyl groups bonded to nitrogen that resist hydrolysis but react in acidic or basic conditions).