Effect of Zr-doping on Pd/CexZr1-xO2 catalysts for oxidative carbonylation of phenol

Ce–Zr solid solution(CexZr1-xO2,CZO)was prepared by the citric acid sol–gel method.The CZO was then used as a support for Pd/CZO catalysts for the oxidative carbonylation of phenol to diphenyl carbonate.The Pd/CZO catalyst showed enhanced activity and diphenyl carbonate selectivity compared with the Pd/CeO2 catalyst.The catalytic performance of Pd/CZO was influenced by the calcination temperature of the CZO support.X-ray diffraction,scanning electron microscopy,N2 adsorption–desorption measurements,X-ray photoelectron spectroscopy and H2 temperature-programmed reduction measurements were used to investigate the effects of Zr doping and calcination temperature.The catalytic performance of Pd/CZO and Pd/CeO2 for the oxidative carbonylation of phenol was affected by several factors,including the specific surface area,Ce^3+and/or oxygen vacancy content,oxygen species type and Pd(II)content of the catalyst.All these properties were influenced by Zr doping and the calcination temperature of the CZO support.

Methane oxidative carbonylation catalyzed by rhodium chalcogen halides over carbon supports

Gas phase carbonylation of methane is studied in the presence of molecular oxygen over pure carbon carriers and carbon supported rhodium chalcogen halides. Activated carbons and fullerene blacks have been used as carbon supports. XPS and IR-spectroscopy data show the formation of rhodium chalcogen halides in solids prepared by different methods. We have found that the productivity of acetic acid by carbon supported rhodium chalcogen halides depends strongly on the carbon carrier and the method of the catalyst preparation. Namely, the catalyst with highest productivity for the acetic acid is prepared by synthesizing the rhodium chalcogen halide over the carbon support followed by thermal destruction. We have also found that rhodium chalcogen halides over activated carbons are more active compared with fullerene supported catalysts.

Catalytic perfomance of rhodium chalcogen halides and rhodium chalcogenides over silica supports in methane oxidative carbonylation

The gas phase methane oxidative carbonylation was studied in the presence of molecular oxygen over silica materials including their mechanical mixtures with rhodium chalcogen chlorides obtained in non-aqueous inorganic media. The formation of Rh4SCl7, Rh4S9Cl2, Rh4SesCl3 and Rh3Se3Cl solids was confirmed by elemental analysis, IR absorption spectroscopy, XPS and X-ray diffraction. Silica, vanadium-, and molybdenum-containing mesoporous molecular sieves have been used as supports. It was found that productivity of oxygenates （methanol, methyl acetate and acetic acid） depends mainly on the method of the catalyst preparation and the type of the support.

N-Heterocyclic Carbene-Palladium Complex Catalyzed Oxidative Carbonylation of Amines to Ureas

Palladium carbene shows high efficiency without any promoter on oxidative carbonylation of amines to ureas and a new type of palladium carbene complex containing both an aniline and an NHC ligands was found to be the active species for the reaction.

Novel fabrication of copper oxides on AC and its enhanced catalytic performance on oxidative carbonylation of methanol

Copper oxides（CuOx） nanoparticles dispersed on activated carbon（AC） were prepared by using vaporphase methanol as the reducing agent. The CuOx/AC as prepared exhibited an enhanced catalytic activity in oxidative carbonylation of methanol to dimethyl carbonate（DMC）. The catalytic performance was significantly influenced by reduction conditions including temperature and time. With the similar selectivity of DMC, the space time yield（STY） under optimal reduction conditions reached up to 408 mg g^-1h^-1, which is superior to conventional methods such as thermolysis and solvothermal reduction. Based on the characterization results of XRD, TEM and XPS, the good copper dispersion and high Cu^＋ content obtained by vapor-phase methanol reduction were mainly responsible for the high catalytic activity.

Selenium-catalyzed Oxidative Carbonylation of Benzylamines to 1,3-Dibenzylureas

A facile, efficient and cost-effective approach to 1,3-dibenzylurea was reported. With cheap and recycla- ble nonmetal selenium as catalyst, carbon monoxide instead of phosgene derivatives as earbonylation agent and oxygen as oxidant, the selenittm-catalyzed oxidative carbonylation reaction of benzylamines can proceed efficiently in one-pot manner in the presence of triethylamine to afford the desired 1,3-dibenzylttreas mostly in moderate to excellent yields. Selenium catalyst can be easily recovered due to its vhase-transfer catalvtic function and recycled

Effect of Triptolide on Expression of Oxidative Carbonyl Protein in Renal Cortex of Rats with Diabetic Nephropathy

The traditional Chinese medicine（Tripterygium wilfordii Hook.f., TWH） has been clinically used to treat primary and secondary renal diseases and proteinuria for nearly 40 years. However, there is a rare literature about the effect of triptolide（the main active ingredient of TWH） on the expression of oxidative carbonyl protein（OCP） in diabetic nephropathy（DN）. This study aimed to provide experimental evidence for triptolide treatment on DN through its effect on the expression of OCP, in order to investigate the effects of triptolide on the expression of OCP in rats with DN. Sixty SD rats were randomly divided into five groups： control group, high-dose triptolide（Th） group, low-dose triptolide（Tl） group, DN model group, and positive control（benazepril） group. The DN model was established using streptozotocin. Urinary protein excretion, fasting blood glucose（FBG）, superoxide dismutase（SOD） in renal homogenate, malondialdehyde（MDA） in renal homogenate and renal nitrotyrosine by immunohistochemistry, and the expression of OCP by oxyblotimmune blotting were detected. In the DN model group, rat urinary protein excretion and renal MDA were significantly increased, while renal SOD significantly decreased and nitrotyrosine expression was obviously upregulated in the kidney. After triptolide treatment, 24-h urinary protein excretion（61.96±19.00 vs. 18.32±4.78 mg/day, P〈0.001）, renal MDA（8.09±0.79 vs. 5.45±0.68 nmol/L, P〈0.001）, and nitrotyrosine expression were decreased. Furthermore, renal OCP significantly decreased, while renal SOD（82.50±19.10 vs. 124.00±20.52 U/L, P〈0.001） was elevated. This study revealed that triptolide can down-regulate the expression of OCP in the renal cortex of DN rats.