Ube Industries, Inc.

Susumu Tahara

Keigo Nishihira

Masaoki Matsuda

Kozo Fujii

Katsuhiko Mizutare

Takashi Miyatake

Yukio Inaba

Hiroyuki Sawada

Junichiro Kita

Keig Nishihira

Taisei Igarashi

A process for the preparation of a 2,3-dihydro-2-methyl-2,3-dialkyl-7-oxybenzofuran having the formula (I): ##STR1## in which R and R' are the same or different and each represents a lower alkyl group or hydrogen atom, which comprises reacting catechol with an aldehyde having the formula (II):

Preparation of 2,3-dihydro-2-methyl-2,3-dialkyl-7-oxybenzofurans

There is provided a process for the continuous preparation of a diester of oxalic acid, which comprises a first step of reacting carbon monoxide with an ester of nitrous acid in the gaseous phase; a second step of condensing the gaseous reaction mixture to separate a non-condensed gas from a condensed liquid containing the diester of oxalic acid; a third step of introducing the non-condensed gas of the second step to a regeneration column, thereby contacting it with a gas containing molecular oxygen and an alcohol, and recycling the resulting gas containing an ester of nitrous acid to the reactor of the first step; a fourth step of distilling out an alcohol containing a diester of carbonic acid formed as a by-product of the first step and obtaining a liquid diester of oxalic acid; and a fifth step of introducing the distillate of the fourth step to a hydrolysis column thereby hydrolyzing the diester of carbonic acid in the gas and recycling the alcohol as an alcohol source for the third step.

Process for continuous preparation of diester of oxalic acid

There is provided a process for the continuous preparation of a diester of oxalic acid which comprises a first step of reacting carbon monoxide with an ester of nitrous acid in the gaseous phase; a second step of condensing the gaseous reaction mixture to separate a non-condensed gas from a condensed liquid containing the diester of oxalic acid; a third step of introducing the non-condensed gas of the second step to a regeneration column and thereby contacting it with a gas containing molecular oxygen and an alcohol to regenerate nitrogen monoxide in the non-condensed gas into an ester of nitrous acid so as to bring the concentration of nitrogen monoxide in the gas at the outlet of the column to a level of from 2 to 7% by volume; and a fourth step of recycling the gas of the third step containing the ester of nitrous acid and from 2 to 7% by volume of nitrogen monoxide to the reactor of the first step.

Process for continuously preparing a diester of oxalic acid

There is disclosed a process for continuously preparing ethylene glycol, which comprises (1) a first step of contacting a gas containing carbon monoxide and an ester of nitrous acid with a solid catalyst of platinum group metal series in the gaseous phase thereby to obtain a product containing a diester of oxalic acid, (2) a second step of condensing the product of the first step thereby to separate a non-condensed gas containing nitrogen monoxide formed by the catalytic reaction of the first step from a condensed liquid containing the diester of oxalic acid, (3) a third step of contacting the non-condensed gas of the second step with a gas containing molecular oxygen and an alcohol, and recycling the resulting gas containing an ester of nitrous acid to the first step, (4) a fourth step of contacting the condensed liquid of the second step containing the diester of oxalic acid and hydrogen with a catalyst for hydrogenation in the gaseous phase thereby to obtain a product containing ethylene glycol, (5) a fifth step of distilling the product of the fourth step thereby to distill out the alcohol and to obtain ethylene glycol, and (6) a sixth step of recycling the alcohol of the fifth step as an alcohol source for the third step.

Process for continuously preparing ethylene glycol

A process for preparing an N-alkylene-diamine by contacting an alkylene diamine with an aliphatic aldehyde in a reaction solvent in the presence of hydrogen under pressure and an platinum group metal, which comprises gradually adding the aliphatic aldehyde to the alkylene diamine. The process according to the present invention provides a high conversion of the alkylene diamine and a high selectivity to the N-alkyl-alkylene-diamine.

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Ube, Japan

Susumu Tahara