US 12,252,468 B2
Method for purifying waste N-methyl-2-pyrrolidone mixture solution
Sung Won Shim, Jeollanam-do (KR)
Assigned to JAEWON INDUSTRIAL CO., LTD, Jeollanam-do (KR); and EM TECH. CO., LTD, Chungcheongnam-do (KR)
Appl. No. 17/604,049
Filed by JAEWON INDUSTRIAL CO., LTD, Jeollanam-do (KR); and EM Tech. CO., LTD, Chungcheongnam-do (KR)
PCT Filed Jul. 7, 2020, PCT No. PCT/KR2020/008854
§ 371(c)(1), (2) Date Oct. 15, 2021,
PCT Pub. No. WO2021/006598, PCT Pub. Date Jan. 14, 2021.
Claims priority of application No. 10-2019-0082112 (KR), filed on Jul. 8, 2019.
Prior Publication US 2022/0144772 A1, May 12, 2022
Int. Cl. C07D 207/26 (2006.01)
CPC C07D 207/26 (2013.01) 4 Claims
 
1. A method for purifying waste N-methyl-2-pyrrolidone (NMP) mixed solution comprising N-methylsuccinimide (NMS) and γ-butyrolactone (GBL) being a by-product of NMP, the method comprising:
adding a base comprising NaBH4 (SBH) to the waste NMP mixed solution to perform a reaction of converting the NMS to 5-hydroxy-N-methyl-2-pyrrolidone and converting the GBL to 1,4-butanediol, whereby the NMS and the GBL are simultaneously removed,
wherein the SBH is added in an amount of 0.05 to 0.10 wt % based on the total weight of the waste NMP mixed solution,
wherein water is added in an amount of 5 to 20 wt % based on the total weight of the NMP mixed solution and the base, a temperature of the reaction is 100 to 150° C., and the reaction is performed for 10 to 60 minutes.