Introduction to Carboxylic Acids

If necessary, review the suggested sections to prepare for this chapter. 

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Carboxylic acids, which were introduced in Section 3.4, are compounds with a —COOH moiety. These compounds are abundant in namre, where they are responsible for some familiar odors. 

Carboxylic acids are also found in a wide range of pharmaceuticals that are used to treat a variety of conditions. 

Each year the United States produces over 2.5 million tons of acetic acid from methanol and carbon monoxide. The primary use of acetic acid is in the synthesis of vinyl acetate, which is used in paints and adhesives. 

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S. Carbonel, C. Fayet, and J. Gelas, Introduction of a carboxyl group through an acetal as a new route to carboxylic acid derivatives of sugars, Carbohydr. Res., 319 (1999) 63-73. 

In the present synthesis, the preparation of two cyclic ethers (31) and (41) and their transformations to pisiferic acid (1) are described. In this synthesis, the introduction of carboxylic acid at angular position has been accomplished by transannular oxidation. 

A method of preventing aggregation of nanotubes is described. The procedure entails the ambient temperature introduction of carboxylic acids onto the nanotube substrate using a mixture of ammonium persulfate and sulfuric acid. By this method up to 0.76meq/g carboxylic acid was introduced onto a nanotube surface after two days. 

Reductive carbonylation of 1,1-dibromocyclopropanes with tetracarbonylnickel in dimethyl-formamide in the presence of a nucleophile is a powerful method for direct introduction of carboxylic acid functions to cyclopropanes. Nucleophiles, such as alcohols, amines, and silylamines, are particularly reactive and give cyclopropyl esters and amides, respectively, in reasonable to good yields, e.g. formation of 5 and... 

Alternatively a dialkylacetonitrile with two different alkyl groups is readily obtained by two successive monoalkylations. The usual mild conditions are employed to introduce two primary alkyl groups introduction of more hindered alkyl groups requires reflux in THF for extended periods of time. In practice it is not necessary to isolate the intermediate monoalkyl derivative. Since dialkyl-acetonitriles are readily hydrolyzed to carboxylic acids, this new procedure provides an alternative to the classical malonic ester synthesis.9... 

Oxidahon of alcohol to carboxylic acid + 1 Little change Introduction of acidic function. pK 3-5, reduction of log of 3-5 units... 

Because the dissociation of a carboxylic acid is an equilibrium process, any factor that stabilizes the carboxylate anion relative to undissociated carboxylic acid will drive the equilibrium toward increased dissociation and result in increased acidity. An electron-withdrawing chlorine atom, for instance, makes chloroacetic acid (Ka = 1.4 x 10-3) approximately 80 times as strong as acetic acid introduction of two chlorines makes dichloroacetic acid 3000 times as strong as acetic acid, and introduction of three chlorines makes trichloroacetic acid more than 12,000 times as strong. 

Carboxylic acid derivative (Chapter 21 introduction) A compound in which an acyl group is bonded to an electronegative atom or substituent Y that can act as a leaving group in a substitution reaction, RCOY. 

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