Neopentyl Glycol Production

The process under analysis comprises three major sections: (1) Aldol Condensation; (2) Hydrogenation; and (3) Purification.

Aldol Condensation. An aldol reactor is fed with an aqueous solution of formaldehyde, isobutyraldehyde and triethylamine. In such reactor, an aldol condensation reaction between isobutyraldehyde and formaldehyde is carried out in the presence of triethylamine catalysts. The output from the aldol condensation reactor, containing crude hydroxypivaldehyde, is submitted to extraction with octanol and distillation for the recovery of a purified hydroxypivaldehyde.

Hydrogenation. The purified hydroxypivaldehyde is fed to a loop-type reactor, along with hydrogen gas. There, a reaction between hydroxypivaldehyde and hydrogen takes place, in the presence of Raney nickel catalysts. Such hydrogenation reaction yields a mixture containing crude Neopentyl Glycol, which is then submitted to a saponification step. In the saponification, the hydrogenation product is mixed with caustic soda, in such a way that the precursors still present in the stream are converted to Neopentyl Glycol.

Purification. In this section, the stream rich in Neopentyl Glycol and a stream containing residual NPG content are fed to an extractor. Water is used as solvent for Neopentyl Glycol removal. The aqueous phase from the extraction is fed to a distillation column, which further separates a mixture of Neopentyl Glycol and water from salt impurities. The Neopentyl Glycol and water mixture is fed to the last column, which further purifies the NPG. High-purity Neopentyl Glycol withdrawn from column bottom is routed to a finishing step and stored.