Zn(salen) complexes have been employed as active catalysts for the formation of cyclic carbonates from epoxides and CO2. A series of kinetic experiments was carried out to obtain information about the mechanism for this process catalyzed by these complexes and in particular about the order-dependence in catalyst. A comparative analysis was done between the binary catalyst system Zn(salphen)/NBu...

A series of ZnMgNiAl layered double hydroxides (LDHs) containing 20 wt.% Ni and different Zn/Mg molar ratios were prepared by a coprecipitation method, and then were introduced with H2PO4 via a microwave-hydrothermal method. With the resulting mixtures as the precursors, Zn/Mg-modified ZnMgNi–P/Al2O3 catalysts were prepared. The Zn/Mg molar ratio affected the formation of Ni2P and Ni12P5 in nic...

methanol steam reforming plays a pivotal role to produce hydrogen for fuel cell systems in a low temperature range. to accomplish higher methanol conversion and lower co production, the reaction was catalyzed by cuznfe mixed oxides. various ratios of fe and cu/zn were coprecipitated in differential method to optimize the cuznfe structure. the sample containing 45cu50zn5fe (wt. %) revealed its m...

mgcl2/c2h5oh adducts with constant relative ratio of 1/3 were prepared and kept at 120oc for different lengths of times of 5, 10, 20, 30, 50, 90,120 and 220 h. then the samples were quenched and analyzed by xrd and bet. no meaningful changes were observed in the specific surface area of the samples, while xrd spectra showed 3 peaks at 2θ<15o for samples kept at 120oc for 5 h. these 3 peaks were...

In this study, the hydrolytic reaction mechanism of HPNP by two effective mononuclear Zn(II) catalysts was explored by using density functional calculations. With the assumption that the active catalyst is in Zn-aqua form, the water-assisted proton transfer mode was found to be energetically the most favorable one for both the catalysts among three possible reaction pathways. The rate-limiting ...

carbon nanotubes were synthesized over a series of zn-containing fe/alumina catalysts by chemical vapor deposition method at two reaction temperatures of 850 and 950 °c using methane as a carbon source. catalysts were synthesized by keeping fe concentration constant and varying zn concentration to study the effects of zn. the catalysts were characterized using x – ray powder diffraction and n2 ...

Zinc-aluminium layered double oxide (Zn-Al-LDO) catalysts derived from layered double hydroxides (LDHs) were prepared and used for the catalytic fast pyrolysis of cellulose to selectively produce 1-hydroxy-3,6dioxabicyclo[3.2.1]octan-2-one (LAC), which is a valuable anhydrosugar derivative. Analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed to invest...

Under the green chemistry perspective, bis[(l)prolinate-N,O]Zn (also called zinc-proline or Zn[(l)-pro]2) has proven its competence as a promising alternative in a plethora of applications such as catalyst or promoter. Owing to its biodegradable and non-toxic nature of bis[(l)prolinate-N,O]Zn, it is being actively investigated as a water soluble green catalyst for synthetic chemistry. Bis[(l)pr...

A series of trinuclear, triptycene-based metallosalphen complexes (M = Zn, Ni) have been prepared incorporating various peripheral substituents. The introduction of Zn metal centres into these triptycene based salphen ligands gives rise to cross-linking between different triptycene molecules through μ-phenoxo bridges between the Zn metal centres, and variation in the peripheral groups allows th...

The direct synthesis process of dimethyl ether (DME) from syngas in slurry reactors is considered to be promising because of its advantages in caloric transfer. In this paper, the influences of operating conditions (temperature, pressure and weight hourly space velocity) on the conversion of CO, selectivity of DME and methanol were studied in a stirred autoclave over Cu-Zn-Al-Zr slurry catalyst...