Novel reaction of N,N'-bisarylmethanediamines with formaldehyde. Synthesis of some new 1,3,5-triaryl-1,3,5-hexahydrotriazines.
The acid-catalyzed cyclocondensation of N,N'-bisaryl (aryl = 2-pyrimidinyl, 2-pyrazinyl and 4-nitrophenyl) methanediamines 5a-c with aqueous formaldehyde in refluxing acetonitrile leads to the formation of the corresponding 1,3,5-triaryl-1,3,5-hexa-hydrotriazines 6a-c. The stoichiometric reactions of 2-aminopyrimidine and 2-amino-pyrazine with aqueous formaldehyde in acetonitrile under reflux conditions also afforded 6a and 6b, respectively. Treatment of 2-aminopyrimidine with aqueous formaldehyde in a 3:2 ratio yielded N,N',N"-tris(2-pyrimidinyl)dimethylenetriamine (7a) as a sole product, which upon subsequent reaction with formaldehyde also afforded 6a. The reaction of N,N'-biphenylmethanediamine with formaldehyde was also investigated.
Hexahydro-s-triazine: A Trial for Acid-Degradable Epoxy Resins with High Performance
Hexahydro-s-triazine (HT) derivatives are acid-sensitive compounds. 4,4′,4″-(1,3,5-Hexahydro-s-triazine-1,3,5-triyl) tris(N-(2-aminoethyl) benzamide) (HT-A) bearing three amino groups was synthesized as a curing agent to prepare the acid-degradable epoxy resin. The chemical structures of HT-A and its precursor were confirmed by 1H NMR and 13C NMR. The synthesized HT-A, as well as the commercialized 4,4′-diaminodiphenylmethane (DDM) (for use as the control) were used to cure diglycidyl ether of bisphenol A (DGEBA), respectively. The property examinations performed by dynamic mechanical analysis (DMA), differential scanning calorimeter (DSC), thermogravimetric analysis (TGA), and tensile test demonstrated that the HT-A-cured epoxy presented high thermal and mechanical properties which were comparable with those of the DDM cured one. Meanwhile, degradation investigation indicated that the HT-A-cured epoxy could be controllably degraded with strong acid stimuli. Thus, HT-A has a great potential to produce rec...
Impact of Nuclear Data Uncertainties on Transmutation of Actinides in Accelerator-Driven Assemblies
Abstract The potential impact of nuclear data uncertainties on a large number of performance parameters of reactor cores dedicated to the transmutation of radioactive wastes is discussed. An uncertainty analysis has been performed based on sensitivity theory, which underlines the cross sections, the energy range, and the isotopes that are responsible for the most significant uncertainties. To provide guidelines on priorities for new evaluations or validation experiments, required accuracies on specific nuclear data have been derived, accounting for target accuracies on major design parameters. The required accuracies (mostly in the energy region below 20 MeV), in particular for minor actinide data, are of the same order of magnitude of the achieved accuracies on major actinides. Specific requirements also concern the improvement of minor actinide data related to decay heat and effective delayed-neutron fraction assessment.