Gasdurchlässigeit von mit Hexamethylen-bis-methyloldihydroxyäthylenharnstoff vernetztem Zellglas. I. Synthese von Hexamethylen-bis-methyloldihydroxyäthylenharnstoff und Hexamethylen-bis-methyloldihydroxyäthylenharnstoff

The synthesis of two compounds, believed to be new, is described, which are partculary suitable for crosslinking of cellophane: Hexamethylen-bis-dihydroxyethyleneurea (CH₂)₆ bis-DHÄH] = 1,6 bis-4,5-dihydroxy-2-imidazolidinone-1-yl]-hexane (I) and hexamethylene-bis-methyloldihydroxyethyleneurea (CH₂)₆ bis-MDHÄH] = 1,6 bis-3-methylol-4,5-dihydroxy-2-imidazolidinone-1-yl]-hexane (II). (I) was prepared by addition of glyoxal to hexamethylenediurea. since (I) is very soluble in water and not crystallizable the byproducts and remainders had to be removed by a special ion-exchange method and by column chromtography. The same operation was applied to the purification of (II). Compouunds (I) and (II) have been checked by analysis of nitrogen and N-methylol groups, by molecular weight determinations and IR-spectra. The reaction-optimum was found by controlling with thin layer chromatography. Practically a 100% conversion was obtained with the addition of glyoxal (I) and a 95% conversion with the methylolation (11) under these conditions, either related to their initial ureas.