Chao Qian

Nitrile-Promoted Alkene Epoxidation with Urea–Hydrogen Peroxide (UHP)

Abstract An efficient method for alkene epoxidation has been studied systematically using benzonitrile and the complex urea–hydrogen peroxide (UHP), which is an anhydrous form of hydrogen peroxide and has the potential to release hydrogen peroxide in a controlled manner and thus avoid the need to slowly add aqueous H2O2 to the reaction mixture. The absence of water in the reaction media was also beneficial, because it minimized undesired reactions of the oxidized products. A range of alkenes was epoxidized by this method, providing yields ranging from 79% to 96%. Supplemental materials are available for this article. Go to the publishers online edition of Synthetic Communications® to view the free supplemental file. GRAPHICAL ABSTRACT

Isolation and purification of d-mannose from palm kernel

An economically viable procedure for the isolation and purification of d-mannose from palm kernel was developed in this research. The palm kernel was catalytically hydrolyzed with sulfuric acid at 100 degrees C and then fermented by mannan-degrading enzymes. The solution after fermentation underwent filtration in a silica gel column, desalination by ion-exchange resin, and crystallization in ethanol to produce pure d-mannose in a total yield of 48.4% (based on the weight of the palm kernel). Different enzymes were investigated, and the results indicated that endo-beta-mannanase was the best enzyme to promote the hydrolysis of the oligosaccharides isolated from the palm kernel. The pure d-mannose sample was characterized by FTIR, (1)H NMR, and (13)C NMR spectra.

A novel method for N-alkylation of aliphatic amines with ethers over γ-Al2O3

A novel and simple method for the N-alkylation of amines with different ethers as alkylating reagents has been developed, using cheap γ-Al2O3 as the catalyst at atmospheric pressure in the temperature range of 260–320°C. For example, the reaction of equimolar amounts of morpholine and diethyl ether gave N-ethylmorpholine quantitatively. The present catalytic system is applicable to the N-alkylation of both primary and secondary amines. Since only water is generated as byproduct, the protocol proved to be eco-friendly and atom-economic.

Amination of aliphatic alcohols catalyzed by CuO–NiO/γ–Al2O3

The amination of aliphatic alcohols in the gas–solid phase was investigated in a fixed-bed reactor in the presence of CuO–NiO/γ–Al2O3 as the catalyst. This catalytic system was successfully applied for both the N-methylation of aliphatic amines and N-alkylation of piperidine with primary or secondary alcohols. N-Alkylation of piperidine with low-carbon alcohols resulted in high conversions and selectivities, and the conversion of piperidine and the selectivities toward the desired products declined gradually with the increase of the carbon number of aliphatic alcohols. The influence of varied conditions on the N-cyclohexylation of piperidine was also evaluated, including liquid hourly space velocity (LHSV), temperature and the catalyst; especially the catalyst had the greatest impact. Finally, the test of the catalyst’s stability was performed.Graphical Abstract

Application of alkoxide in catalytic transfer hydrogenation of unsaturated nitrogen compounds

Alcoholate was utilized in catalytic transfer hydrogenation of unsaturated nitrogen compounds. In the reduction of nitro compounds, oximes and imines, alkoxide was used as the promoter, with alcohol as the hydrogen source, while in the reduction of nitriles, alkoxide was used as the hydrogen source.

Highly efficient nitration of phenolic compounds using some nitrates and oxalic acid under solvent-free conditions

Nitrophenols can be obtained by direct nitration of phenols with some nitrates and oxalic acid at room temperature in moderate to high yields under solvent-free conditions. A small amount of water proved to be important in the initial period of the reaction.

An improved procedure for the synthesis of 3,4-ethylenedioxythiophene

An improved procedure for the synthesis of 3,4-ethylenedioxythiophene is reported starting from ethyl chloroacetate. Reaction with sodium sulfide gave diethyl thiodiglycolate which was then reacted with diethyl oxalate, and then 1,2-dibromoethane to give 2,5-dicarbethoxy-3,4-ethylenedioxythiophene. Hydrolysis, and decarboxylation gave 3,4-ethylenedioxythiophene in 16% overall yield. The structures of the key intermediates in synthetic routes were confirmed, and every step was optimised, to give a procedure suitable for large-scale industrial production.

Preparation of Activated Carbon from the Residue of Plasma Pyrolysis of Coal by Steam Activation

This work mainly evaluated the feasibility of preparation of activated carbon from the residue of plasma pyrolysis of coal from Karamay, China, by steam activation. The demineralization was brought in to analyze the effect of ash content on the porosity development of activated carbon. The maximum Brunner–Emmet–Teller surface area of the activated carbon obtained from the residue was 387 m2/g. After NaOH-HCl demineralization, the reactivity between steam and char was reduced and the surface area of the activated carbon was increased. The initial ash affects the porosity development. A first-order reaction model between steam and char was established. The apparent activation energy was ascertained by Arrhenius equation.

Investigation into the synthesis of C-25 oxysterols

A simple and environmentally benign method for the preparation of 25-hydroxycholesterol, a modulator of cholesterol biosynthesis, has been developed. The final product can be obtained by the reaction of mCPBA and 24-dehydrocholesterol, followed by reduction with lithium aluminium hydride in THF in moderate yields.

Catalytic transfer hydrogenation of aryl sulfo compounds

A new method to reduce aryl sulfo compounds via transfer hydrogenation was investigated, using Pd/C as a catalyst, and 2-propanol or formic acid as hydrogen sources. This new process is simple and clean.