Mitsubishi Gas Chemical Company, Inc.

Junichi Amemiya

Ikutaro Kuzuhara

Masafumi Watanabe

Naoshi Mori

In the production of spiroglycol by the reaction of pentaerythritol and hydroxypivalaldehyde in water in the presence of an acid catalyst, (A) a total content of amines and amine salts in hydroxypivalaldehyde is reduced to 1.5% by weight or lower; (B) seed crystals are added to the reaction system before initiating the reaction and/or during the reaction in an amount from 1.5 to 30% by weight on the basis of the total feed amount of pentaerythritol, hydroxypivalaldehyde, water, the acid catalyst and the seed crystals, each being fed into the reaction system; (C) the pH of the reaction system is kept from 0.1 to 4.0 from initiation of the reaction to completion of the reaction; and (D) the sum of a maximum theoretical amount of spiroglycol to be synthesized from pentaerythritol and hydroxypivalaldehyde to be fed into the reaction system and an amount of spiroglycol contained in the seed crystals to be added to the reaction system is controlled within a range from 5 to 35% by weight on the basis of the total feed amount. The spiroglycol produced has an increased particle size. By washing the spiroglycol with a basic solution, the heat stability is improved.

Process for producing spiroglycol

A method for producing flake-like dried DOG by making DOG containing from 10 to 50% by mass of a liquid go through a continuous melt-drying step of a specified condition and then making it go through, as a next step, a vacuum-drying step of a specified condition or a ventilation-drying step of a specified condition while holding a molten state thereof, to obtain DOG in which the liquid in DOG is reduced to not more than 0.5% by mass (dried DOG), and flaking the obtained dried DOG in a flake production step.

Process for production of flake-like dried 2-(5-ethyl-5-hydroxymethyl-1,3-dioxan-2-yl)-2-methylpropan-1-ol

A process of producing 2-(5-ethyl-5-hydroxymethyl-1,3-dioxane-2-yl)-2-methylpropane-1-ol (DOG) by the acetalization of hydroxypivalaldehyde with trimethylolpropane in water in the presence of an acid catalyst and optional seed crystals. DOG crystals having an increased particle size and containing the trans isomer in a high content are produced by the process in which the reaction temperature, pH of the reaction system and concentration of DOG to be produced in the reaction system are controlled.

Process of producing dioxane glycol

The present invention provides a method of producing high-purity hydroxypivalaldehyde and/or dimer thereof, including: reacting isobutyl aldehyde with formaldehyde in a presence of a basic catalyst; distilling a low boiling point component including unreacted isobutyl aldehyde to obtain an aqueous solution; adding a diluent to the aqueous solution; cooling the aqueous solution to crystallize the hydroxypivalaldehyde and/or the dimer thereof; and subjecting the aqueous solution to a solid-liquid separation, followed by washing with an organic solvent and/or water, in which the diluent and a basic compound are added to the aqueous solution containing the hydroxypivalaldehyde and/or the dimer thereof obtained by distilling the low boiling point component off so that a concentration of the hydroxypivalaldehyde and/or the dimer becomes 5 to 23% by mass, the concentration of formaldehyde becomes 0.2 to 2.5% by mass, and a pH value becomes 5.0 or more, the solution is crystallized at a temperature of 20 to 45&#xb0; C. and subjected to the solid-liquid separation. In this method, handling of a high-viscosity slurry and carrying out any complicated operation such as regeneration of an ion exchange resin are not required, so the high-purity HPA and/or the dimer thereof can be obtained in high yield with an energetically advantageous manner.

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Okayama, Japan

Junichi Amemiya