نتایج جستجو برای: acid catalyst

تعداد نتایج: 784490  

2014
Zhen Liu Zhongdong Zhang Wei Xing Sridhar Komarneni Zifeng Yan Xionghou Gao Xiaoping Zhou

Three kinds of HZSM-5 nanoparticles with different acidity were tailored by impregnating MgO or varying Si/Al ratios. Both the textural and acidic properties of the as-prepared nanoparticles were characterized by nitrogen adsorption-desorption measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), ammonia temperature-programmed desorption (NH3-TPD) and Fourier transform infr...

2013
Els De Canck Inmaculada Dosuna-Rodríguez Eric M. Gaigneaux Pascal Van Der Voort

A Periodic Mesoporous Organosilica (PMO) functionalized with sulfonic acid groups has been successfully synthesized via a sequence of post-synthetic modification steps of a trans-ethenylene bridged PMO material. The double bond is functionalized via a bromination and subsequent substitution obtaining a thiol functionality. This is followed by an oxidation towards a sulfonic acid group. After fu...

1-Methyl-3-(2-oxyethyl)-1H-Imidazol-3-ium-Borate Sulfonic Acid ([MOEI]-BSA) was easily prepared and used as a new and highly efficient solid acid catalyst for the synthesis of benzimidazole derivatives with high isolated yields. Various substituted benzimidazoles were synthesized by a combination of o-phenylenediamines and aldehydes in the presence of [MOEI]-BSA with excellent yields in water a...

2017
Francesco Mecozzi Jia Jia Dong Pattama Saisaha Wesley R Browne

α-Hydroxy ketones are valuable synthons in organic chemistry. Here we show that oxidation of vic-diols to α-hydroxy ketones with H2O2 can be achieved with an in situ prepared catalyst based on manganese salts and pyridine-2-carboxylic acid. Furthermore the same catalyst is effective in alkene epoxidation, and it is shown that alkene oxidation with the MnII catalyst and H2O2 followed by Lewis ac...

2012
Ping Li Chang-Yan Cao Zhe Chen Hua Liu Yu Yu Wei-Guo Song

The cascade reaction sequence is a fascinating subject in catalysis. A rationally designed cascade reaction sequence can simplify the synthetic route, reduce the amount of waste and lower the operation cost. The key for a successful cascade reaction sequence is the multifunctional catalyst. With a suitable multifunctional catalyst, multiple synthesis steps can proceed in one pot with high yield...

Journal: :organic chemistry research 2015
khodabakhsh niknam nassim - borazjani

silica-bonded n-propyldiethylenetriamine sulfamic acid (spdtsa) is employed as a recyclable heterogeneous solid acid catalyst for the synthesis of benzopyrano[2,3-d]pyrimidines  through one-pot condensation reaction of salicylaldehydes, malononitrile and secondary amines  at room temperature under solvent-free conditions. spdtsa showed much the same efficiency when used in consecutive reaction ...

1998
Gary Lickfield Charles Q. Yang Weishu Wei Wei Chen

N-methylol compounds, such as dimethyloldihydroxyethyleneurea (DMDHEU), are the most commonly used durable press finishing agents for cotton fabrics by the industry. In this research, we have examined the effects of the catalyst systems used for DMDHEU on the mechanical strength of the crosslinked cotton fabric. The catalysts induce degradation of cellulose as indicated by the decrease in the t...

2017
Mahsa Yarhosseini Shahrzad Javanshir Zahra Dolatkhah Mohammad G Dekamin

A simple solvent-free protocol for the preparation of flunixin, a potent non-narcotic, non-steroidal anti-inflammatory drugs is reported using boric acid as catalyst. Its salt, flunixin meglumine are then prepared under reflux in EtOH. This sustainable method are then extended for the synthesis of a series of 2-(arylamino) nicotinic acid derivatives. The present protocol combines non-hazardous ...

Journal: :iranian chemical communication 2016
mahdieh chegeni ardeshir khazaei shahnaz saednia

nanocrystalline sio2–hclo4, as a newly reported catalyst, has been used as an efficient and reusable catalyst for the synthesis of pyrimidine derivatives. the procedure can be successfully applied to the efficient synthesis of mono substituted pyrimidine derivatives, using triethyl orthoformate, ammonium acetate, methyl ketone derivatives. in practice, this method is a combination of a satisfac...

2012
Fei-ling Pua Zhen Fang Sarani Zakaria Feng Guo Chin-hua Chia

Correction We found an important error in our published paper [1]. On page 7, Section: One-step conversion of Jatropha oil to biodiesel, line 3, we wrote a reaction temperature of 120degreesC. The correct temperature should be 220degreesC. The pressure was also omitted from the same reaction description and should be 7.1 MPa. Direct production of biodiesel from high-acid value Jatropha oil with...

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