in this study, an efficient and green process for the synthesis of dihydropyrimidin-2(1h)-ones from aromatic benzaldehydes, ethyl acetoacetate and urea using al-mcm-41 as heterogeneous catalyst and microreactor under solvent-free conditions has been developed. the advantages of this method are easy work-up procedure, regeneration of the catalyst, clean and neutral reaction conditions.

Several mesoporous nickel-based catalysts with MgO-Al2O3 as the catalyst support were prepared using a co-precipitation method at a constant pH. The supports were prepared from the decomposition of an Mg-Al hydrotalcite-like structure which had already been prepared with Mg/Al=1. Prior to impregnating 10 wt.% nickel on the supports, the precursor was decomposed at several ...

The kinetic parameters of ethylene combustion in the presence of acetic acid, i.e., during the synthesis of vinyl acetate and in the absence of acetic acid, have been measured in the temperature range 413–453 K over Pd supported on a high surface area SiO2 (600 m 2/g) at pressures ranging from 5.0 to 15.0 kPa of C2H4 and 1.0 to 10.0 kPa of O2. CO2 formation as a function of the partial pressure...

Metal-organic frameworks with Zr6 nodes, UiO-66 and NU-1000, were investigated as supports for Ir(CO)2 and Ir(C2H4)2 complexes. A single bonding site for the iridium is identified on the nodes of NU-1000, whereas two sites are identified on UiO-66, although at low iridium loadings only one site is occupied. Density functional theory calculations provide structural results that are in good agree...

Fundamental understanding of the dependence between structure and composition on electrochemical CO2 reduction reaction (CO2RR) would guide rational design highly efficient selective electrocatalysts. A major impediment to deep multi-carbon products is complexity carbon–carbon bond coupling. The chemically well-defined catalysts with atomically dispersed dual-metal sites are required for these ...

Since the discovery of ruthenium as a catalyst for hydrogenation reactions, Ru catalysts have been widely used in the chemical, petrochemical, food, and pharmaceutical industries, and in energy-conversion technologies. The scope of homogeneous Ru catalysts has been well-illustrated recently. However, heterogeneous catalysts can be preferable from both industrial and environmental perspectives. ...

In the framework of time-dependent density-functional theory, we study electron emission from Na clusters and the C2H4 molecule as induced by irradiation with an intense pulse. The collision of a charged projectile on C2H4 is also explored for comparison. We look in particular at the level depletion, i.e. the electron loss in each single-electron level separately. It is found that the distribut...

Positive and negative secondary ions desorbed from metal foils by bombardment with 252Cf fission products have been investigated by time-of-flight mass spectroscopy. The measurements were performed under UHV conditions using metal foils of Cu, Ni and Al cleaned by Ar-ion etching. Spectra were taken with cleaned surfaces and also under the exposure of H2 , 0 2 , N2 , CO, C2H4 , C2H6 and C3H70H u...

sio2-supported silyl chromate catalyst is an important industrial catalyst for production of high grade hdpepipe materials. the control of the short chain branch (scb) distribution using this catalyst system is still a greatchallenge. in this work, ethylene and 1-hexene copolymers were synthesized using sio2-supported silyl chromatecatalyst combined with triisobutylaluminium (tiba), triethylalu...