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  • Author: S. Ismail x
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MICHAEL condensation of 2-cinnamoylbenzimidazoles (1 a-h) with ethyl cyanoacetate, cyanoacetamide and acetoacetamide led to the formation of 2(1 H)pyridone derivatives (2 a-c), (3 a-c), 4a-c), and (5 a-c). Compounds (2 a-c) added GRIGNARD reagents at the nitrile group to give 5a-c. CLAISEN condensation of 5 a-c with ethyl acetate gave the corresponding diketo derivatives (6a-c), respectively. Cyclization of 6 b with ethanolic hydrogen chloride gave the 8-azachromone (7). Both 6 and 7 gave the same pyrazole derivative (8) upon the reaction with phenylhydrazine.

Catalytic combustion of toluene over ceramic monolith supported Mn, Fe, Co, Cu and Zr oxide-based catalysts has been investigated. The catalysts were prepared by washcoating and characterized by Scanning Electron Microscopy (SEM) technique. The adhesion of the washcoat was evaluated using an ultrasonic technique. The increase in activity was followed by increasing metal oxide content. 6.5MnO2/CM (CM: ceramic monolith) catalyst exhibited the highest catalytic activity, over which the toluene conversion is up to 90 percent at a temperature of 291°C.

Abstract

The a.c. conductivity as a function of temperature was measured for ten prepared samples. The measurements were carried out in the temperature range 25–340°C. The sample CuMn2O4 prepared either from oxide or carbonate contains the least impurity content, while the sample Cu1.5Mn1.5O4 from oxide origin and Cu1.6Mn1.4O4 from carbonate origin contain the highest impurity content. The activation energy ΔE 1 values for the oxide origin samples are nearly the same of those obtained from carbonate origin. The variation of ΔE 2 values with concentration of copper content (x) appears to be consistent.