Optical spectral verification of a harmful impurity to palladium catalyst

The condensation of glyoxal with benzylamine leaded to hexabenzylhexaazaisowurtzitane(HBIW) with formic acid catalyst, and at the same time some side products were produced. Some impurities in HBIW would be harmful to the palladium catalyst used in the hydrogenolysis of HBIW, subsequently resulting in the low yield or failure of the catalytic reaction. The impurities in hexabenzylhexaazaisowurtzitane were distilled by means of recrystal technic, which were isolated by preparative chromato-graph. The structure of the main impurity was studied with FTIR, ¹H-NMR, ESI-MS, and element analysis. The result shows that the structure is confirmed as N,N'-dibenzyl-oxalamide. which was synthesized in the way reported in the literature, and was charactered by FTIR, ¹H-NMR and EI-MS. And the optical spectra data of the sample synthesized and the substance isolated from the impuries were the same, testifying that the substance isolated was N, N'-dibenzyl-oxalamide ulteriorly. N,N'-dibenzyl-oxalamide was added in the hydrogenolysis system of HBIW catalyzed by Pd catalyst. The result shows that N,N'-dibenzyl-oxalamide can reduce the activity of Pd catalyst, and when the quantity of N,N'-dibenzyl oxalmide added achieves 0.9% of the weight of HBIW, the reaction of catalytic hydrogenolysis fails.