Pivalic acid

• 2,2 - dimethylpropanoic acid
• Trimethyl
• Neopentanoic

Colorless crystals with unpleasant smell

Fixed

0.91 g · cm -3 ( 20 ° C)

33-35 ° C

163-164 ° C

8.5 Pa ( 20 ° C)

5.03 (20 ° C)

25 g · l-1 water (20 ° C)

Risk

900 mg · kg -1 ( LD50, rat, oral)

Template: Infobox chemical / molecular formula search available

Pivalic acid is a carboxylic acid selected from the group of the four isomeric pentanoic acids, and the simplest cooking acid ( tertiary saturated monocarboxylic acids).

Representation

Synthetic pivalic acid can be obtained by oxidation of pinacolone, by Grignard reaction of tert- butyl chloride ( lower illustration ) or by the Koch reaction of 2- methylpropene ( isobutene ), carbon monoxide and water:

Properties

The pivalic acid forms colorless, needle-shaped crystals of pungent odor, which dissolves slightly in water, but well in ethanol and diethyl ether. By steric effects on the molecule pivalic acid, in comparison to other valeric acids to some specific characteristics, such as the formation and the hydrolysis of the ester Pivalinsäureester is considerably more difficult.

Use

Pivalic acid is used for the preparation of polyvinyl esters ( vinyl pivalate ), and pharmaceutical preparations. In this case, one uses the effect of the steric inhibition by the use of esters of medically active substances that are absorbed slowly, and then cleaved in the organism, such as Testosteronpivalat.

Safety

Pivalic acid is flammable, the ignition temperature is about 500 ° C, the flash point in closed crucible at 64 ° C. The acid irritates the eyes, respiratory tract, mucous membranes and skin and can be absorbed through the skin.