Perchloric Acid Adsorbed on Silica Gel (HClO4—SiO2) as an Inexpensive, Extremely Efficient, and Reusable Dual Catalyst System for Acetal/Ketal Formation and Their Deprotection to Aldehydes/Ketones.

ChemInform ◽  
2007 ◽  
Vol 38 (20) ◽  
Author(s):  
Raj Kumar ◽  
Dinesh Kumar ◽  
Asit K. Chakraborti
Keyword(s):  
Silica Gel ◽  
Perchloric Acid ◽  
Catalyst System

Butadiene polymerization over a π-allylnickel-alumina-silica gel catalyst system

1980 ◽  
Vol 13 (4) ◽  
pp. 319-322 ◽  
Author(s):  
W. Skupiński ◽  
M. Zawartke ◽  
St. Malinowski
Keyword(s):  
Silica Gel ◽  
Catalyst System ◽  
Butadiene Polymerization

scholarly journals Environmental-Friendly Synthesis of Alkyl Carbamates from Urea and Alcohols with Silica Gel Supported Catalysts

Catalysts ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 579
Author(s):  
Yubo Ma ◽  
Lei Wang ◽  
Xiaodong Yang ◽  
Ronghui Zhang
Keyword(s):  
Silica Gel ◽  
Supported Catalysts ◽  
Scale Up ◽  
Supported Catalyst ◽  
Catalyst System ◽  
Ethyl Carbamate ◽  
Impregnation Method ◽  
Methyl Ethyl ◽  
Environmental Friendly ◽  
Alkyl Carbamate

TiO2/SiO2, Cr2O3-NiO/SiO2, and TiO2-Cr2O3/SiO2 were prepared by the impregnation method for alkyl carbamate synthesis using urea as the carbonyl source. Up to 97.5% methyl carbamate yield, 97% ethyl carbamate yield, and 96% butyl carbamate yield could be achieved, respectively. The catalysts were characterized by ICP-AES, BET, XRD, XPS, NH3-TPD, and EPMA. Catalytic activity investigation revealed that TiO2/SiO2, Cr2O3-NiO/SiO2, and TiO2-Cr2O3/SiO2 were effective catalysts for methyl carbamate (MC), ethyl carbamate (EC), and butyl carbamate (BC), respectively. The recycling tests suggested that these silica gel supported catalyst system is active, stable, and reusable. A total of 96–97% alkyl carbamate (methyl, ethyl, and butyl) could be obtained in a 2 L autoclave, and these data suggested that our catalyst system is relatively easy to scale up.

Perchloric Acid Adsorbed on Silica Gel: An Efficient Heterogeneous Reusable Catalyst for Synthesis of 1,5-Benzodiazepines.

ChemInform ◽  
2006 ◽  
Vol 37 (6) ◽  
Author(s):  
Biswanath Das ◽  
Majjigapu Ravinder Reddy ◽  
Ravirala Ramu ◽  
Kongara Ravinder Reddy ◽  
Madamanchi Geethangili
Keyword(s):  
Silica Gel ◽  
Perchloric Acid ◽  
Reusable Catalyst

Comparison of Different Heterogeneous Catalysts for the Estolides Synthesis from Oleic Acid

2011 ◽  
Vol 364 ◽  
pp. 288-292 ◽  
Author(s):  
Nor Asikin Mohamad Nordin ◽  
Nadia Farhana Adnan ◽  
Noraini Hamzah ◽  
Wan Nor Roslam Wan Isahak ◽  
Alifee Ayatillah ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Silica Gel ◽  
Perchloric Acid ◽  
Heterogeneous Catalysts ◽  
Addition Reaction ◽  
Xps Analysis ◽  
Reaction Products ◽  
Final Conversion ◽  
Direct Addition ◽  
Chromatographic Peaks

Different catalysts, namely various loading of perchloric acid on various supports; HClO4/silica (SiO2), HClO4/silica gel (SG) and HClO4/alumina (Al2O3) were tested for the direct addition reaction of oleic acid (OA) to form estolide compounds. The reactions were carried out under vacuum (2 mBar) for 10 hours at 70 °C under solvent-less conditions. LC-MS ToF of reaction products results showed chromatographic peaks for the presence of two new estolide compounds, oleic-oleic monoestolide acid (m/z563.51, as [M-H]-), and oleic-oleic diestolide acid (m/z845.77 [M-H]-). The optimum loading of HClO4for every support are 15 wt.% HClO4/SiO2(SiO215), 10 wt.% HClO4/SG (SG10) and 35 wt.% HClO4/Al2O3(Al2O335). The SG10 turned out to be the best catalyst, achieving a final conversion of 97.5 % with 79.8 % selectivity to oleic-oleic monoestolide acid and 17.7 % selectivity to oleic-oleic diestolide acid. The activity and selectivity of the SG10 have been investigated and compared with homogeneous HClO4. The optimum catalysts for every support were characterized by XPS analysis, BET, TEM and TPD-NH3.

ChemInform Abstract: Sulfonamidoglycosylation of Methyl Glycosides Employing Perchloric Acid Supported on Silica Gel.

ChemInform ◽  
2009 ◽  
Vol 40 (3) ◽  
Author(s):  
Pedro A. Colinas ◽  
Nicolas A. Nunez ◽  
Rodolfo D. Bravo
Keyword(s):  
Silica Gel ◽  
Perchloric Acid
Sign in / Sign up

Export Citation Format

Share Document