	US 12,071,394 B2
	Method for removing monoisocyanates from organic solution
Robert E. Hefner, Jr., Rosharon, TX (US); Helge Braun, Lake Jackson, TX (US); Armenio Costa, Estarreja (PT); and Brian Cramm, Lake Jackson, TX (US)
Assigned to Dow Global Technologies LLC, Midland, MI (US); and Dow, Portugal Produtos Quimicos, Sociedade Unipessoal, Estarreja (PT)
Appl. No. 17/288,967
Filed by Dow Global Technologies LLC, Midland, MI (US); and Dow Portugal Produtos Quimicos, Sociedade Unipessoal, LDA, Estarreja (PT)
PCT Filed Jul. 31, 2019, PCT No. PCT/US2019/044434 § 371(c)(1), (2) Date Apr. 27, 2021, PCT Pub. No. WO2020/091867, PCT Pub. Date May 7, 2020.
Claims priority of provisional application 62/753,495, filed on Oct. 31, 2018.
Prior Publication US 2021/0403418 A1, Dec. 30, 2021
Int. Cl. C07C 263/10 (2006.01); C07C 263/20 (2006.01); C07C 273/18 (2006.01); C08G 18/76 (2006.01)

CPC C07C 263/10 (2013.01) [C07C 263/20 (2013.01); C07C 273/1818 (2013.01); C07C 273/1827 (2013.01); C07C 273/1881 (2013.01); C08G 18/7664 (2013.01)]

9 Claims

1. A method for removing phenyl isocyanate from an organic solvent, comprising the steps of:

a) contacting i) a starting solution containing at least 85 weight percent, based on the weight of the starting solution, of one or more organic solvents inert to reaction with isocyanate and amine groups and 1.5 to 15 weight percent, based on the weight of the starting solution, of phenyl isocyanate, with ii) at least one amine selected from the group consisting of aniline, MDA and PMDA, in proportions sufficient to provide 0.01 to 0.8 equivalents of primary and/or secondary amino groups per equivalent of isocyanate groups in the starting solution; and

b) reacting at least a portion of the phenyl isocyanate with at least a portion of the amine to form a slurry of the one or more urea compounds in the one or more organic solvents.