Catalytic synthesis of 2-methylpyrazine over Cr-promoted copper based catalyst via a cyclo-dehydrogenation reaction route

Abstract

The cyclo-dehydrogenation of ethylene diamine and propylene glycol to 2-methylpyrazine was performed under the atmospheric conditions at 380°C. The Cr-promoted Cu-Zn/Al 2 O 3 catalysts were prepared by impregnation method and characterized by ICP-AES, N 2 adsorption/desorption, XRD, XPS, N 2 O chemisorption, TPR and NH 3 -TPD techniques. The amorphous chromium species existing in Cu-Zn-Cr/Al 2 O 3 catalyst enhanced the dispersion of active component Cu, promoted the reduction of catalyst. Furthermore, the catalytic performance was significantly improved. The acidity of the catalyst played an important role in increasing the 2-MP selectivity. To optimize the reaction parameters, influences of different chromium content, reaction temperature, liquid hourly space velocity (LHSV), reactants molar ratio and time on stream on the product pattern were studied. The results demonstrated that addition of chromium promoter revealed satisfying catalytic activity, stability and selectivity of 2-methylpyrazine.

Ab initioatomistic thermodynamics study of the early stages of Cu(100) oxidation

“…In particular, oxidation of copper surfaces is of fundamental and practical importance. Copper, CuO, and Cu 2 O are candidates to replace rare and expensive noble metal catalysts for applications including methane synthesis, [1][2][3] catalytic conversion of nitrogen oxides, 4 water-gas shift, 5,6 and preventing CO poisoning in fuel cells. 7,8 The mechanisms manifested in the early stages of copper oxidation are not well understood, especially under different environmental conditions.…”

Reductive Amination of 1-Hydroxy-2-propanone Over Nickel and Copper Catalysts

“…Moreover, the copper catalysts show high dehydrogenation activity that is increased by addition of chromium as a promoter. Chromium improves the dispersion of copper on the surface of the catalyst 21 and prevents its sintering. Consequently, primary products of amination of acetol (2-APOL) can be easily dehydrogenated to very reactive α-amino carbonyl or α-amino imine compounds that are considered precursors of nitrogenous heterocyclic compounds (see Schemes 5 and 6).…”

Aldol condensation of acetic acid with formaldehyde to acrylic acid over Cs(Ce, Nd) VPO/SiO2 catalyst

“…180 C. However, the temperatures of these NH 3 desorption proles were in a wide range of 100-600 C, indicating that all the catalysts had weak-, mild-and strong acid sites. 17,38 It was found that at lower ratios of metallic cation to vanadium ranging from 0.05 to 0.1 for Cs and Nd and from 0.05 to 0.2 for Ce, the metallic cation-modied VPO/SiO 2 catalysts exhibited higher acidities than the VPO/SiO 2 catalyst. Upon further increasing the metallic cation/vanadium ratio to 0.3, the acidities of the metallic cation-modied VPO/SiO 2 catalysts decreased.…”