水相中无催化剂合成四氢苯并吡喃衍生物(英文)

水相中无催化剂合成了2-氨基-7,7-二甲基-5-氧代-4-芳基-4H-苯并吡喃-3-氰基-5,6,7,8-四氢苯并[b]吡喃,其结构经1H NMR,IR和元素分析表征。

Inorganic-organic hybrid photocatalysts:Syntheses,mechanisms,and applications

Inorganic-organic hybrid materials are promising for application in the field of photocatalysis because of their excellent properties.Therefore,their syntheses,mechanisms,and applications are reviewed in this paper.First,we introduce the role of inorganic-organic photocatalysts,their advantages and disadvantages,and their design principles.Second,we present the top-down and bottom-up synthesis methods of the hybrid materials.The interaction between inorganic and organic components in hybrid materials is discussed,followed by how to improve inorganic-organic photocatalysts.Third,the applications of hybrid materials in the field of photocatalysis,such as realizing hydrogen evolution,organic pollutant degradation,heavy metals and CO_(2) reduction,sterilization,and nitrogen fixation,are examined.Finally,the application prospects and development directions of inorganic-organic hybrid materials are explored and the unsolved problems are described.

Synthesis of 4,4＇-MDC in the Presence of Sulfonic Acid-functionalized Ionic Liquids

The synthesis of methylene diphenyl dimethylcarbamate （4,4＇-MDC） from methyl N-phenyl carbonate （MPC） and formaldehyde （HCHO） was conducted in the presence of sulfonic acid-functionalized ionic liquids （ILs） as dual solvent-catalyst. The influences of the kind of anion in the ionic liquids, reaction conditions and the recycle of the ionic liquid on 4,4＇-MDC synthesis reaction were investigated. In addition, the acid strength of ILs was de-termined by the Hammett method with UV-visible spectroscopy, and the acid strength-catalytic activity relationship was correlated. The activity estimation results showed that [HSO3-bmim]CF3SO3 was the optimal dual solvent-catalyst. Under the suitable reaction conditions of 70℃, 40 min, molar ratio of nMPC/nHCHO= 10/1 and mass ratio of WILs/WMPC = 4.5/1, the yield of 4,4＇-MDC based on HCHO was 89.9 % and the selectivity of 4,4＇-MDC with respect to MPC was 74.9%. Besides, [HSO3-bmim]CF3SO3 was reused four times after being purified and no significant loss in the catalytic activity was observed.

Efficient Solvent-free Synthesis of Chloropropene Carbonate from the Coupling Reaction of CO_2 and Epichlorohydrin Catalyzed by Magnesium Porphyrins as Chlorophyll-like Catalysts

Highly efficient solvent-free coupling reaction of carbon dioxide(CO2)and epichlorohydrin catalyzed by meso-tetraphenyl porphyrin magnesium(MgTPP)in the presence of triethylamine as co-catalysts is reported.As a chlorophyll-like catalyst,MgTPP showed excellent activity for the coupling reaction of CO2 and epichlorohydrin to chloropropene carbonate,in which the turnover number could reach up to 9200.Moreover,different factors including the amount of catalyst,reaction temperature,pressure and time were systematically investigated and the optimal reaction conditions were obtained(epichlorohydrin 50 mmol,MgTPP 5.0×10- 3mmol,triethylamine 6.25×10-3 mmol,140°C,1.5 MPa,8 h).A plausible two-pathway mechanism for the coupling reaction of CO 2and epichlorohydrin is proposed to propound the catalysis of MgTPP.

Macro kinetics for synthesis of dimethyl carbonate from urea and methanol on Zn-containing catalyst

In a stainless steel autoclave,the synthesis kinetics of dimethyl carbonate(DMC) from urea and methanol was separately investigated without catalyst and with Zn-containing catalyst.Without catalyst,for the first reaction of DMC synthesis(the reaction of urea with methanol to methyl carbamate(MC)),the reaction kinetics can be described as the first order with respect to the concentrations of both methanol and urea.For the second reaction of DMC synthesis(the reaction of MC with methanol to DMC),the results exhibit characteristics of zero-order reaction.For Zn-containing catalyst,the first reaction is neglected in the kinetics model since its rate is much faster than the second reaction.The macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model,in which a side reaction in forming process of DMC is incorporated since it decreases the yield of DMC drastically at high temperature.The activation energy of the reaction from MC to DMC is 104 kJ/mol while that of the side reaction of DMC is 135 kJ/mol.The highest yield of DMC is 23%.

Solvent-free synthesis of zeolite catalysts

The most used method for preparation of zeolites is hydrothermal synthesis from silicate or aluminosilicate gels at temperatures in the range of 60-200 ℃. Excess water used in the industrial process results in several issues, including high autogeneous pressure, low efficiency, pollution, etc. To solve these problems, several strategies have been developed. This review describes the solvent-free synthesis of zeolites. The combination of solvent-free synthesis and organotemplate-free synthesis can open the pathway to a highly sustainable zeolite synthesis protocol in industry.

Catalyst-Free Synthesis and Shape Control of CdTe Nanowires

The procedure reported here allows for the size and shape control of CdTe nanowires by means of colloidal chemistry. Thus, ultrathin, straight, saw-tooth-like and one-sided branched nanowires with zinc blende structures could be synthesized. Their formation does not require any catalyst and is most likely due to the oriented attachment of nanoparticles formed in the beginning of the reaction. The use of oleylamine as a solvent turned out to be crucial in order to achieve CdTe nanowires. The reaction between oleic acid and oleylamine in the presence of CdO proved to be essential, not only to activate the Cd precursor but also to provide reaction conditions facilitating nanowire formation by oriented attachment.

1,3-Dibromo 5,5-dimethylhydantoin (DBH):A novel and efficient catalyst for the synthesis of 14-aryl-14H-dibenzo[a,j] xanthenes under solvent-free conditions

An atom-efficient and environment-friendly approach for the synthesis of aryl-14H-dibenzo[a,j]xanthenes (3a–o) via the one-pot reaction of β-naphthol and aryl aldehydes (1) catalyzed by DBH has been developed. The present approach offers several advantages such as reduced reaction times, moderate temperature, higher yields, solvent free, eco-friendly reaction condition, easy purification and economic availability of the catalyst.