Method of preparing diisocyanate composition

Patent metadata

Field	Value
Publication number	US-11987541-B2
Application number	US-202217719905-A
Country	US
Kind code	B2
Filing date	Apr 13, 2022
Priority date	Dec 6, 2019
Publication date	May 21, 2024
Grant date	May 21, 2024

Abstract

In the embodiments, an aqueous hydrochloric acid solution instead of hydrogen chloride gas and solid triphosgene instead of phosgene gas may be used in the process of preparing a diisocyanate from a diamine through a diamine hydrochloride. In addition, the embodiments provide processes for preparing a diisocyanate composition and an optical lens, which are excellent in yield and quality with mitigated environmental problems by controlling the size of the diamine hydrochloride composition, the b* value according to the CIE color coordinate of the diamine hydrochloride composition, or the content of water in the diamine hydrochloride composition within a specific range.

First claim

The invention claimed is:

1. A process for preparing a diisocyanate composition, which comprises:
obtaining a diamine hydrochloride composition by reacting diamine with an aqueous hydrochloric acid solution and then adding a first organic solvent; and
obtaining a diisocyanate composition by reacting the diamine hydrochloride composition with triphosgene,
wherein the diamine hydrochloride composition has a b* value of 1.2 or less according to the CIE color coordinate when dissolved in water at a concentration of 8% by weight,
wherein the step of obtaining the diisocyanate composition further comprises step B for treating the diamine hydrochloride composition after the diamine hydrochloride composition is obtained,
wherein step B for treating the diamine hydrochloride composition comprises washing the diamine hydrochloride composition with a solvent having a polarity index of 5.7 or less,
wherein in the step of washing the diamine hydrochloride composition, the b* value according to the CIE color coordinate of the diamine hydrochloride composition is adjusted,
wherein the first organic solvent and the solvent having a polarity index of 5.7 or less are different, and
wherein the solvent having a polarity index of 5.7 or less comprises dichloromethane.

2. The process for preparing a diisocyanate composition of claim 1 , wherein the content of Fe ions in the aqueous hydrochloric acid solution is 0.5 ppm or less,
the aqueous hydrochloric acid solution comprises 20% by weight to 45% by weight of hydrochloric acid, and
the diamine and the aqueous hydrochloric acid solution are introduced to the reaction at an equivalent ratio of 1:2 to 5 at a temperature of 20° C. to 40° C.

Assignees

• Skc Co Ltd
• Woori Fine Chem Co Ltd
• Sk Pucore Co Ltd

Inventors

• Pai Jaeyoung
• Kim Jeongmoo
• Han Hyuk Hee
• Myung Jung Hwan

Classifications

• C07C263/20 Primary

  Separation; Purification · CPC title

• C07C265/14

  containing at least two isocyanate groups bound to the same carbon skeleton · CPC title

• C07C263/10 Primary

  by reaction of amines with carbonyl halides, e.g. with phosgene · CPC title

• C07C209/74

  by halogenation, hydrohalogenation, dehalogenation, or dehydrohalogenation · CPC title

• G02B1/04

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title