We report herein on a new method to achieve a high yield of hydrocarbons from hydrothermal catalytic hydrodenitrogenation (HDN) of indole, which is higher than that from conventional pyrolysis methods. The main hydrocarbon products were aromatic hydrocarbons and alkanes, which are similar to fossil oils to be used as liquid fuels in the future. Catalyst screening experiments show that noble metal catalysts (e.g., 5 wt % Pt, Pd, or Ru) supported on porous solids (e.g., carbon, Al2O3) enhanced the conversion of indole to hydrocarbons under hydrothermal condition. Of those different catalysts, Pd/γ-Al2O3 shows the greatest influence on the yield of hydrocarbons, which we focus on the catalyst Pd/γ-Al2O3 in more details. On the basis of the Pd/γ-Al2O3 catalyst, the effects of time, temperature, and H2 pressure on the hydrocarbons were discussed. HDN of the indole reaction at 450 °C, 0.015 g/cm3 water density, 5 MPa H2, and 50 wt % Pd/γ-Al2O3 loading led to a maximum yield (51 mol %) of hydrocarbons at 120 min. It proposes the mechanism to acquire hydrocarbons from hydrogenational indole denitrogenation, which experiences two different pathways, as (1) indole is directly hydrodenitrogenated into hydrocarbons, and (2) intermediate oxygenated products from hydrolysis of partly hydrodenitrogenated indole were hydrodeoxygenated to removal of O to acquire hydrocarbons. The factors for deactivation of catalyst under hydrothermal condition are also discussed by the results from characterizing the surface, bulk structure, and microscopy experiments.

The reaction of phenylacetonitrile in supercritical methanol and ethanol in a system containing a small volume of water was studied. The effects of various operating conditions, such as reaction temperature, reaction time, the mole ratio of phenylacetonitrile/water/methanol or ethanol on the product yield were systematically investigated. The optimal yield of methyl phenylacetate for phenylacetonitrile in supercritical methanol in a system containing a small volume of water was 70 % at 583 K and 2.5 h. The optimal yield of ethyl phenylacetate for phenylacetonitrile in supercritical ethanol with a small volume of water was 80 % at 583 K and 1.0 h. At the same time, a feasible mechanism was proposed for phenylacetonitrile in supercritical methanol and ethanol in a system containing a small volume of water.

Palladium catalysts supported on nitrogen-incorporated SBA-15(SBA-15-N) prepared using sol-immobilization are found to be highly efficient and reusable catalysts for the solvent-free oxidation of benzyl alcohol using molecular oxygen under low pressure. The samples were characterized by XRD, N2 adsorption- desorption, ICP, EA, FTIR, Pyridine-IR and TEM techniques. The results indicated that nitrogen was incorporated into the SBA-15 framework, and the nitridation treatment was an alternative and effective way to modify the properties of the SBA-15 for immobilizing Pd. It was supposed that the interaction between the surface-NHx groups and Pd precursors was the key to immobilizing Pd. The catalyst displayed an obvious improvement in catalytic activity, showing a high selectivity of benzyl alcohol oxidation. The 2 %Pd/SBA-15-900 N catalyst also can be readily recovered and reused at least five consecutive cycles without significant leaching and lose its catalytic activity.

We herein report a mild method for the preparation of dihydrobenzofurans through hydrothermal catalytic tandem Claisen rearrangement–intramolecular hydroaryloxylation of allyl phenyl ethers. This reaction provides a new method for constructing dihydrobenzofurans, a process that is potentially applicable to natural product synthesis. SBA-15, TS-1, HZSM-5 were chosen as catalysts in a hydrothermal reaction medium between 200 and 320 °C. HZSM-5 catalyst showed the highest catalytic activity, and the effects of molar ratio of allyl phenyl ether–water, time, pressure, temperature and catalyst on the Claisen hydroaryloxylation in hydrothermal condition were investigated. The latter two process variables had the greatest influence on the product yields and distribution. A series of allyl phenyl ether derivatives were also treated in hydrothermal condition with HZSM-5 catalyst to offer high yield of corresponding dihydrobenzofurans.

Graphene oxide functionalized with gama-aminopropyltriethoxysilane, is used as support for the immobilization of homogeneous heteropoly phosphotungstic acid. It is synthesized and characterized by SEM, XPS, XRD, 31P NMR and Raman. The effects of catalyst parameters and reaction conditions on the oxidation reaction of benzyl alcohol are systematically investigated. Under optimal conditions, the catalyst exhibit remarkably enhanced catalytic activity (conversion 76 % and selectivity 99 %). And the catalyst could be separated conveniently. Moreover, the loss of PW12O403− anion from the support under the reaction conditions is responsible for the deactivation of the catalyst.

The reaction between caprolactam and ethanol was performed in near-critical water. The primary product (ethyl-6-aminohexanoate) was identified by GC-MS. The influences of the reaction temperature, residence time, initial ratio (reactant/water), pH, and additives on the yields of ethyl-6-aminohexanoate are discussed. The results showed that the yield of ethyl-6-aminohexanoate could be as high as 98 % with SnCl2 as an additive in near-critical water. At the same time, the reaction between caprolactam and ethanol was estimated by a lumped kinetic equation as a second-order reaction in near-critical water, and the activation energy was evaluated according to the Arrhenius equation under acidic and basic conditions. Based on the results, the reaction mechanism between caprolactam and ethanol in near-critical water is proposed.

The reduction of pyruvic acid in near-critical water has successfully been conducted under conditions of various temperatures, pressures, reaction time and the presence of formic acid as the reducing agent. In this work, additives (K2CO3, KHCO3, and sodium acetate) used in the reduction of pyruvic acid were also investigated. The results showed that by adding K2CO3 (25 mole %) a markedly higher lactic acid yield (70.7 %) was obtained than without additives (31.3 %) at 573.15 K, pressure of 8.59 MPa, 60 min, and in the presence of 2 mol L−1 formic acid. As a base catalyst, K2CO3 definitely accelerated the reduction of pyruvic acid. The reaction rate constants, average apparent activation energy and pre-exponential factor were evaluated in accordance with the Arrhenius equation. The reaction mechanism of the reduction was proposed on the basis of the experimental results.

In this article, a new group of SO3H-functionalized ionic liquids based on benzimidazolium cation was synthesized and used as environmentally benign catalysts for the one-pot synthesis of biscoumarin derivatives. The ionic liquids showed high catalytic activities and reusabilities with good to excellent yields of the desired products. H0 (Hammett function) values and the minimum-energy geometries of SO3H-functionalized ionic liquids were determined and the results revealed that the acidities and catalytic activities of ionic liquids in the synthesis of biscoumarin derivatives were related to their structures.

•CuPd–Cu2O/Ti-powder is prepared using a simple impregnation method.•CuPd–Cu2O/Ti-powder exhibits excellent activity and stability after activation.•CuPd(alloy)–Cu2O formed during the reaction contributes to the activity and stability.The oxidation of alcohols to carbonyl compounds in gas-phase is of great importance in organic chemistry and industrial process. Herein, the catalyst CuPd–Cu2O/Ti-powder is prepared by depositing Cu(NO3)2 and Pd(NO3)2 on Ti powder support followed by in-situ activation in reaction stream, which delivers high-performance for the gas-phase oxidation of alcohols. Compared with Cu/Ti-powder and Pd/Ti-powder, CuPd–Cu2O/Ti-powder exhibits higher stability and activity in alcohol oxidation reaction. The catalyst is characterized by XRD, XPS, TEM and ICP. The results indicate that CuPd(alloy)–Cu2O formed during the reaction contributes to the high activity and stability.Download full-size image