Patent · US Expired

Process for isolating 4,4'-diaminodiphenylmethane

US4008275A · kind A · utility

2Cited by
8References
15Claims
0Family size

Assignee

Inventors

Key dates

Filing dateAug 18, 1975
Grant dateFeb 15, 1977
Priority date—
Expiry dateAug 18, 1995

Classification

  • Technology area (CPC C)Chemistry; Metallurgy
  • CPC primaryC07C211/50
  • WIPO fieldOrganic fine chemistry
  • WIPO sectorChemistry

Abstract

2,2'- AND 2,4'-DIAMINODIPHENYLMETHANE ARE SELECTIVELY REMOVED FROM ADMIXTURES THEREOF WITH THE 4,4'-ISOMER BY HEATING THE ISOMER MIXTURE AT 30.degree. TO 100.degree. C in the presence of styrene, .alpha.-alkylstyrenes, or the mono- or diamino nuclear substituted derivatives thereof and a catalyst (mineral acid, clays, diatomaceous earth, zeolites). The styrene or .alpha.-alkylstyrene can be employed as such or generated in situ from a precursor therefor. The process is particularly useful in facilitating the isolation of substantially pure 4,4'-diaminodiphenylmethane from the polyamine mixture obtained by condensation of aniline and formaldehyde.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.