US 11,028,046 B2 · Toluene diisocyanate purification method

Abstract

The present invention relates to a toluene diisocyanate purification method enabling acquisition of a product having a small amount of dimers in a final product by means of using a reactive dividing wall column during toluene diisocyanate preparation. More particularly, according to the present invention, in order to obtain a product having a small amount of dimers in accordance with a reversible reaction of a monomer and a dimer, a purification procedure is designed by means of applying the temperature, pressure, time of stay and the like of a reactive dividing wall column as appropriate particular conditions, a reboiler having short time of stay and high heat transfer rate is used, and thus a dimerization reaction is inhibited and the purity and yield of the product are enhanced. Therefore, high-purity toluene diisocyanate can be purified and obtained.

Claims13

Dependent claims

A toluene diisocyanate purification method comprising:

separating and purifying toluene diisocyanate by feeding a mixture containing toluene diisocyanate as a main component to a reactive dividing wall column equipped with a condenser and a reboiler,
wherein a pressure of the condenser is maintained at 50 torr or less, and a temperature of the condenser is maintained at 130° C. or less,
a total pressure difference in the reactive dividing wall column is maintained at 40 torr or less,
a retention time of the reaction mixture in the reactive dividing wall column is maintained within 10 seconds to 150 seconds, and
a pressure of the reboiler is maintained at 30 torr or less, and a temperature of the reboiler is maintained at 160° C. or less.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application

16/463,972Filed 12 Dec 2017

Priority

KR 10-2016-017184315 Dec 2016

Published

US 2020/0377447 A13 Dec 2020

Granted

8 Jun 2021

Term ends

Not estimatedThe source records don’t support an estimate.

Classification7 codes

C07C 263/20
Separation; Purification; Stabilisation; Use of additives: separation; Purification
B01D 3/009
Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping: in combination with chemical reactions
B01D 3/141
Fractional distillation or use of a fractionation or rectification column: where at least one distillation column contains at least one dividing wall
B01D 3/322
Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30: reboiler…

Toluene diisocyanate purification method

Life of this patent

Toluene diisocyanate purification method

Life of this patent

Abstract

Claims13