PROPERTIES OF CARBOXYLIC ACIDS

FIGURE 14.1 Acetic acid forms hydrogen bonds with water molecules. 

Write the balanced chemical equation for the ionization of propanoic acid in water. 

The ionization of propanoic acid produces a carboxylate ion and a hydronium ion. O O 

Because carboxylic acids are weak acids, they are completely neutralized by strong bases such as NaOH and KOH. The products are a carboxylate salt and water. The carboxylate ion is named by replacing the ic acid ending of the acid name with ate. 

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In aqueous solution intermolecular association between carboxylic acid molecules IS replaced by hydrogen bonding to water The solubility properties of carboxylic acids are similar to those of alcohols Carboxylic acids of four carbon atoms or fewer are mis cible with water m all proportions... 

The most apparent chemical property of carboxylic acids their acidity has already been examined m earlier sections of this chapter Three reactions of carboxylic acids—con version to acyl chlorides reduction and esterification—have been encountered m pre vious chapters and are reviewed m Table 19 5 Acid catalyzed esterification of carboxylic acids IS one of the fundamental reactions of organic chemistry and this portion of the chapter begins with an examination of the mechanism by which it occurs Later m Sec tions 19 16 and 19 17 two new reactions of carboxylic acids that are of synthetic value will be described... 

The most impotant property of carboxylic acids is implied by their name they act as weak acids in water solution. 

The mechanism of amide formation is a source of insight into the properties of carboxylic acids and amines. Initially, we might expect an amine to act as a base and simply accept a proton from the carboxylic acid. Indeed, that does happen, and a quaternary ammonium salt is formed when the reagents are mixed in the absence of a solvent. For example,... 

Table 1.12 lists some of the physical properties of carboxylic acids. Notice that carboxylic acids have even stronger hydrogen bonding than alcohols. 

Polarity of functional group Because the nitrogen atom attracts electrons more strongly than carbon or hydrogen atoms, the C-N and N-H bonds are polar. As a result, the physical properties of amides are similar to the physical properties of carboxylic acids. 

Physical properties of carboxylic acids and derivatives include solubility, melting point, boiling point, and a few other characteristics. In this section we examine each class and discuss the most important physical properties. (In the upcoming section Considering the Acidity of Carboxylic Acids, we discuss the most important chemical property of Ccirboxylic acids — acidity.)... 

Problem 16.3 Account for the following physical properties of carboxylic acids, (a) Only RCOOH s with five or fewer C s are soluble in water, but many with six or more C s dissolve in alcohols. (f>) Acetic acid in the vapor state has a molecular weight of 120 not 60. (c) Their boiling and melting points are higher than those of corresponding alcohols. M... 

PHYSICAL PROPERTIES OF CARBOXYLIC ACIDS 18-1A Hydrogen Bonding... 

Brimblecombe, P., Clegg, S.L., and Khan, I. 1992. Thermodynamic properties of carboxylic acids relevant to their solubility in aqueous solutions. J. Aerosol. Sci. 23, S901-S904. 

To study the physical and chemical properties of carboxylic acids solubility, acidity, aroma. 

Properties of carboxylic acids and esters Special Equipment... 

Structure and Nomenclature of Acid Derivatives 982 21-3 Physical Properties of Carboxylic Acid Derivatives 988 21-4 Spectroscopy of Carboxylic Acid Derivatives 991 21-5 Interconversion of Acid Derivatives by Nucleophilic Acyl Substitution 997... 

Q Draw and name carboxylic acids and dicarboxylic acids, and use spectral information to determine their structures. Q Describe the trends in the acidity and physical properties of carboxylic acids, and explain how their acidity varies with their substituents. 

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