نتایج جستجو برای: homogeneous catalyst

تعداد نتایج: 113196  

Journal: :iranian chemical communication 2015
seyyedeh cobra azimi kurosh rad-moghadam

a homogeneous ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate doped with licl ([bmim]bf4-licl) was found as catalyst solvents for the synthesis of dicoumarols by the condensation of 4-hydroxycoumarin and aldehyde at 80 ˚c. in this field, several types of aromatic aldehyde, containing electron-withdrawing groups as well as electron-donating groups, were rapidly changed to the correspo...

Journal: :Dalton transactions 2015
Julianne M Thomsen Daria L Huang Robert H Crabtree Gary W Brudvig

Organometallic Ir precatalysts have been found to yield homogeneous Ir-based water-oxidation catalysts (WOCs) with very high activity. The Cp*Ir catalyst series can operate under a variety of regimes: it can either act as a homogeneous or a heterogeneous catalyst; it can be driven by chemical, photochemical, or electrochemical methods; and the molecular catalyst can either act in solution or su...

E. Tavakolinejad Kermani H. Khabazzadeh M. Mahdipour

Dihydropyrimidine and amidoalkyl naphthol derivatives have been prepared efficiently in a one-pot synthesis using ZnCl2/urea and ZnCl2/acetamide deep eutectic systems as reaction medium and homogeneous catalyst. This method offers some advantages such as simple procedure, inexpensive solvent and catalyst and good yields of the final products in short reaction times. The use of non-toxic and env...

2015
Mushtaq Ahmad Anam Asghar Abdul Aziz Abdul Raman Wan Mohd Ashri Wan Daud Andrew C. Marr

Fenton oxidation, an advanced oxidation process, is an efficient method for the treatment of recalcitrant wastewaters. Unfortunately, it utilizes H2O2 and iron-based homogeneous catalysts, which lead to the formation of high volumes of sludge and secondary pollutants. To overcome these problems, an alternate option is the usage of heterogeneous catalyst. In this study, a heterogeneous catalyst ...

Journal: :Chemical reviews 2002
Jairton Dupont Roberto F de Souza Paulo A Z Suarez

For economical and ecological reasons, synthetic chemists are confronted with the increasing obligation of optimizing their synthetic methods. Maximizing efficiency and minimizing costs in the production of molecules and macromolecules constitutes, therefore, one of the most exciting challenges of synthetic chemistry.1-3 The ideal synthesis should produce the desired product in 100% yield and s...

Journal: :Nanoscale 2013
Zhen-Xing Li Wei Xue Bing-Tao Guan Fu-Bo Shi Zhang-Jie Shi Hong Jiang Chun-Hua Yan

Translation of homogeneous catalysis into heterogeneous catalysis is a promising solution to green and sustainable development in chemical industry. For this purpose, noble metal nanoparticles represent a new frontier in catalytic transformations. Many challenges remain for researchers to transform noble metal nanoparticles of heterogeneous catalytic active sites into ionic species of homogeneo...

Journal: :journal of chemical and petroleum engineering 2015
leila vafajoo moslem fattahi mohammad kazemeini

in the present study, a heterogeneous and homogeneous gas flow dispersion model for simulation and optimization of a large-scale catalytic slurry reactor for the direct synthesis of dimethyl ether (dme) from synthesis gas (syngas) and co2, using a churn-turbulent regime was developed. in the heterogeneous flow model, the gas phase was distributed into two bubble phases including small and large...

2004

Background Catalysts improve the rate or selectivity of chemical reactions without being consumed in the chemical reaction. “Supported heterogeneous catalysts” consist of catalytic active sites carried on the surfaces of porous solids, known as “supports”. Such catalytic materials are especially important for chemical manufacturing because they minimize the loss of valuable catalytic materials ...

Journal: :international journal of nano dimension 0
masoud mohammadi zeydi department of organic chemistry, university of guilan, rasht, iran. nosratollah mahmoodi department of organic chemistry, faculty of sciences, university of guilan, rasht, iran.

an efficient, simple and convenient route is described for the synthesis of biscoumarin (3,3'-(arylmethylene) bis (4-hydroxy-2h-chromen-2-one)) by using of recyclable catalyst tio2@ksf. in this method, we synthesis biscoumarin derivatives via 3multi-component reactions (3mcrs) of two equivalent 4-hydroxycoumarin with one equivalent of aromatic aldehydes using 20 mg nano tio2@ksf as homogen...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه گیلان - دانشکده علوم پایه 1388

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