	US 12,146,023 B2
	Method for manufacturing diisocyanate and optical lens
Dal Seong Kim, Gyeonggi-do (KR); Oh Joon Kwon, Gyeonggi-do (KR); Sung Gi Lee, Gyeonggi-do (KR); Gyeong Ha Choi, Chungcheongbuk-do (KR); and Junghwan Shin, Seoul (KR)
Assigned to WOORI FINE CHEM CO., LTD., Gyeonggi-do (KR)
Appl. No. 15/734,645
Filed by WOORI FINE CHEM CO., LTD., Gyeonggi-do (KR)
PCT Filed Jun. 5, 2019, PCT No. PCT/KR2019/006832 § 371(c)(1), (2) Date Dec. 3, 2020, PCT Pub. No. WO2019/235862, PCT Pub. Date Dec. 12, 2019.
Claims priority of application No. 10-2018-0065666 (KR), filed on Jun. 7, 2018; application No. 10-2018-0065667 (KR), filed on Jun. 7, 2018; and application No. 10-2018-0065668 (KR), filed on Jun. 7, 2018.
Prior Publication US 2021/0230352 A1, Jul. 29, 2021
Int. Cl. C08G 18/76 (2006.01); C07C 263/10 (2006.01); C08F 2/06 (2006.01); G02B 1/04 (2006.01)

CPC C08G 18/7642 (2013.01) [C07C 263/10 (2013.01); C08F 2/06 (2013.01); G02B 1/041 (2013.01)]

14 Claims

1. A process for preparing metaxylylene diisocyanate, which comprises:

reacting metaxylylenediamine with an aqueous hydrochloric acid solution in a first organic solvent to obtain metaxylylenediamine hydrochloride through a filtration, wherein the first organic solvent is a hydrophilic solvent; and

reacting the metaxylylenediamine hydrochloride with triphosgene in a second organic solvent to obtain metaxylylene diisocyanate,

wherein the reacting metaxylylenediamine with the aqueous hydrochloric acid solution sequentially comprises:

(1a) introducing the aqueous hydrochloric acid solution to a first reactor;

(1b) further introducing the metaxylylenediamine to the first reactor and stirring; and

(1c) further introducing the first organic solvent to the first reactor and stirring,

wherein the yield of the metaxylylene diisocyanate is 80% or more and the purity of the metaxylylene diisocyanate is 95% or more.