US 11,987,541 B2
Method of preparing diisocyanate composition
Jaeyoung Pai, Gyeonggi-do (KR); Jeongmoo Kim, Gyeonggi-do (KR); Hyuk Hee Han, Gyeonggi-do (KR); and Jung Hwan Myung, Gyeonggi-do (KR)
Assigned to SK PUCORE CO., LTD., Ulsan (KR); and WOORI FINE CHEM CO., LTD., Gyeonggi-do (KR)
Filed by SKC CO., LTD., Gyeonggi-do (KR); and WOORI FINE CHEM CO., LTD., Gyeonggi-do (KR)
Filed on Apr. 13, 2022, as Appl. No. 17/719,905.
Application 17/719,905 is a division of application No. 17/111,949, filed on Dec. 4, 2020, granted, now 11,339,121.
Claims priority of application No. 10-2019-0161538 (KR), filed on Dec. 6, 2019; application No. 10-2019-0162046 (KR), filed on Dec. 6, 2019; and application No. 10-2019-0162047 (KR), filed on Dec. 6, 2019.
Prior Publication US 2022/0234998 A1, Jul. 28, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C07C 263/20 (2006.01); C07C 265/14 (2006.01)
CPC C07C 263/20 (2013.01) [C07C 265/14 (2013.01)] 2 Claims
 
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.