Neopentyl glycol

Neopentyl glycol (IUPAC name: 2,2-dimethylpropane-1,3-diol) is an organic chemical compound. It is used in the synthesis of polyesters, paints, lubricants, and plasticizers. When used in the manufacture of polyesters, it enhances the stability of the product towards heat, light, and water. By esterification reaction with fatty or carboxylic acids, synthetic lubricating esters with reduced potential for oxidation or hydrolysis, compared to natural esters, can be produced.

Reactions
Neopentyl glycol is synthesized industrially by the aldol reaction of formaldehyde and isobutyraldehyde. This creates the intermediate hydroxypivaldehyde, which can be converted to neopentyl glycol by either a Cannizzaro reaction with excess formaldehyde, or by hydrogenation using palladium on carbon.

Owing to its tendency to form cyclic derivatives (see Thorpe-Ingold Effect), it is used as a protecting group for ketones, for example in gestodene synthesis. Similarly it gives boronic acid esters, which can be useful in the cross coupling reactions.

A condensation reaction of neopentyl glycol with 2,6-di-tert-butylphenol gives CGP-7930.

Neopentyl glycol is a precursor to Neopentyl glycol diglycidyl ether. The sequence begins with alkylation with epichlorohydrin using a Lewis acid catalyst. Dehydrochlorination of the resulting halohydrin with sodium hydroxide affords the desired ether.

Research
It has been reported that plastic crystals of neopentyl glycol exhibit a colossal barocaloric effect (CBCEs), which is a cooling effect caused by pressure-induced phase transitions. The obtained entropy changes are about 389 joules per kilogram per kelvin near room temperature. This CBCE phenomenon is likely to be very useful in future solid-state refrigeration technologies.