Description
Neopentyl Glycol Mono(hydroxypivalate) is also known as Hydroxypivalic acid neopentyl glycol ester (HPN). The compound has properties similar to neopentyl glycol but in addition specific characteristics
that are responsible for its increasing use. Manufacturers are Eastman Chemical, BASF, and Mitsubishi Gas. World capacity is estimated at 2000 – 2500 t/a. It is highly soluble in polar organic solvents. Both hydroxyl groups undergo the usual reactions of primary alcohols. As with neopentyl glycol, the quaternary structure contributes to the excellent stability of HPN derivatives.
Uses
Neopentyl Glycol Mono(hydroxypivalate) is used as a diol modifier in polyesters for powder, coil, and automotive coatings. HPN imparts the polyesters excellent weatherability, flexibility and resin solubility as well as lower melt viscosity and glass transition temperature. In powder coatings hydroxypivalic acid neopentyl glycol ester improves the appearance by increasing the flow and leveling, because it gives less cyclic compounds than neopentyl glycol during the polyester synthesis. Because of their improved flexibility polyesters containing HPN are used in automotive coatings to give enhanced stone chip resistance and in coil coatings with high demand on both flexibility and weather resistance. Acrylated hydroxypivalic acid neopentyl glycol ester is used in UV-curable coatings for inks and wood coating.
Preparation
Neopentyl Glycol Mono(hydroxypivalate) is produced by a Tishchenko reaction directly from hydroxypivaldehyde in the presence of a basic catalyst (e.g., aluminum oxide) or classically by thermal treatment. Alternatively, it can be synthesized by esterification of neopentyl glycol with hydroxypivalic acid. High-purity hydroxypivalic acid neopentyl glycol ester is obtained by subsequent distillation.
Flammability and Explosibility
Not classified
