Sumber :Francis A. Carey, 2000, ORGANIC CHEMISTRY, The McGraw-Hill Companies, Inc.

SINTESIS ASAM KARBOKSILAT

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Oxidation of an alcohol yields a carbonyl compound. Whether the resulting carbonyl compound is an aldehyde, a ketone, or a carboxylic acid depends on the alcohol and on the oxidizing agent.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Potassium permanganate and chromic acid convert primary alcohols to carboxylic acids by way of the corresponding aldehyde.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Chromic acid (H2CrO4) is a good oxidizing agent and is formed when solutionscontaining chromate (CrO4

2-) or dichromate (Cr2O72-) are

acidified.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

A primary or secondary alkyl side chain on an aromaticring is converted to a carboxyl group by reaction with astrong oxidizing agent such as potassium permanganateor chromic acid.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

If an alkyl side chain on a benzene ring is oxidized on being heated with chromic acid, the product is benzoic acid or a substituted derivative of benzoic acid.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

When two alkyl groups are present on the ring, both are oxidized.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Grignard reagents react in much the same way with carbon dioxide to yield magnesium salts of carboxylic acids. Acidification converts these magnesium salts to the desired carboxylic acids.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Overall, the carboxylation of Grignard reagents transforms an alkyl or aryl halide to a carboxylic acid in which the carbon skeleton has been extended by one carbon atom.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Primary and secondary alkyl halides may be converted to the next higher carboxylic acid by a two-step synthetic sequence involving the preparation and hydrolysis of nitriles.Nitriles, also known as alkyl cyanides, are prepared by nucleophilic substitution.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT

Once the cyano group has been introduced, the nitrile is subjected to hydrolysis.

Aldehid Dan Alkohol

Alkylbenzene

Haloalkana

SINTESIS ASAM KARBOKSILAT