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Unformatted text preview: Mapua I nstitute of Technology Organic Chemistry Laboratory 2 Final Report Carboxylic Acids and their Derivatives Von Joby M. Romero, K ristine S. Salvador School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Intramuros, Manila, Philippines Experiment No. 5, Submitted on November 17, 2010 at N402 ABSTRACT The core viewpoint of this experiment is carboxylic acid and its derivatives namely the acyl halides, esters, acid anhydrides, and amides. To test the properties and reactivity of these groups or derivatives, the compounds namely acetic acid, acetyl chloride, acetic anhydride and acetamides (arranged respectively) were utilized. The reactions involved are esterification, hydrolysis, anilide formation, hydroxamic acid test, alcoholic silver nitrate test and sodium bicarbonate test. Each of the tests was performed on the individual compounds and a positive result means the presence of that particular group or derivative. By that, we could also classify and compare it with another. 1 I N TRODUCT ION A carboxylic acid is a compound containing a carboxyl group, R-COOH, that has a carbonyl group and a hydroxyl group on the same carbon atom. Carboxylic acids tend to be high-boiling and viscous because the molecules associate together through strong hydrogen bonds. Carboxylic acids are highly oxidized, thus they are often made by oxidation of other compounds. Primary alcohols and aldehydes oxidize to acids, while alkenes and alkynes undergo oxidative cleavage to acids. Carboxylic acid derivatives are compounds with functional groups that can be converted to carboxylic acids by a simple acidic or basic hydrolysis. They include esters, amines, nit riles, acyl halides, and acid anhydrides. These groups of compounds also contain a carbonyl group, but now there is an electronegative atom (oxygen, nitrogen, or a halogen) attached to the carbonyl carbon. In general, more reactive acid derivatives easily react to give less reactive derivatives. Their reactivity decreases in the following order: acyl halides, acid anhydrides, esters, amides, and carboxylate ions. Most of these interconversions take place by nucleophilic acyl substitution wherein a nucleophile adds to the carbonyl group to give a tetrahedral intermediate, and then a leaving group leaves, regenerating the carbonyl group. Any factors that make the carbonyl group more easily attacked by the nucleophile favor the reaction. Some of these factors include: steric and electronic factors which affect the reactivity of the acid derivative towards nucleophilic acyl substitution reactions; steric factors wherein unhindered, accessible carbonyl groups react with nucleophiles more readily than do sterically hindered groups; and electronic factors wherein strongly polarized acid derivatives are attacked more readily than less polar ones....
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