1H NMR in CaCl2·xH2O nanocrystals and water sorption isobars in a CaCl2-silica gel system

1998 ◽  
Vol 39 (2) ◽  
pp. 212-216
Author(s):  
M. M. Tokarev ◽  
S. G. Kozlova ◽  
S. P. Gabuda ◽  
Yu. I. Aristov
Keyword(s):  
Silica Gel ◽  
1H Nmr ◽  
Water Sorption ◽  
Gel System

Selective oxidation of benzylic and allylic alcohols with NaOCl/silica gel system

2009 ◽  
Vol 6 (2) ◽  
pp. 288-292 ◽  
Author(s):  
H. Alinezhad ◽  
M. Tajbakhsh ◽  
R. Soleimani
Keyword(s):  
Selective Oxidation ◽  
Silica Gel ◽  
Allylic Alcohols ◽  
Gel System

scholarly journals The Effect of Adhesive Additives on Silica Gel Water Sorption Properties

Entropy ◽  
2020 ◽  
Vol 22 (3) ◽  
pp. 327
Author(s):  
Karol Sztekler ◽  
Wojciech Kalawa ◽  
Agata Mlonka-Medrala ◽  
Wojciech Nowak ◽  
Łukasz Mika ◽  
...  
Keyword(s):  
Sorption Capacity ◽  
Silica Gel ◽  
Water Sorption ◽  
High Reliability ◽  
Electricity Consumption ◽  
Hydroxyethyl Cellulose ◽  
Poly Vinyl Alcohol ◽  
Dynamic Adsorption ◽  
Metal Plates ◽  
The Impact

Adsorption chillers are characterized by low electricity consumption, lack of moving parts, and high reliability. The disadvantage of these chillers is their large weight due to low adsorbent sorption capacity. Therefore, the attention is turned to finding a sorbent with a high water sorption capacity and enhanced thermal conductivity to increase chiller efficiency. The article discusses the impact of selected adhesives used for the production of an adsorption bed in order to improve heat exchange on its surface. Experiments with silica gel with three commercial types of glue on metal plates representing heat exchanger were performed. The structure of samples was observed under a microscope to determine the coverage of adsorbent by glue. To determine the kinetics of the free adsorption, the amounts of moisture adsorbed and the desorption dynamics the prepared samples of coated bed on metal plates were moisturized and dried in a moisture analyzer. Samples made of silica gel mixed with the adhesive 2-hydroxyethyl cellulose, show high adsorption capacity, low dynamic adsorption, and medium dynamic desorption. Samples containing adhesive poly(vinyl alcohol) adsorb less moisture, but free adsorption and desorption were more dynamic. Samples containing the adhesive hydroxyethyl cellulose show lower moisture capacity, relatively dynamic adsorption, and lower dynamic desorption.

Interior hydroxyls of the silica gel system as studied by silicon-29 CP-MAS NMR spectroscopy

1993 ◽  
Vol 115 (19) ◽  
pp. 8695-8705 ◽  
Author(s):  
I Ssuer Chuang ◽  
David R. Kinney ◽  
Gary E. Maciel
Keyword(s):  
Nmr Spectroscopy ◽  
Silica Gel ◽  
Mas Nmr ◽  
Cp Mas Nmr ◽  
Gel System

scholarly journals Chemical Constituents of the Insecticidal Active Extract of Tinospora crispa

2019 ◽  
Vol 10 (1) ◽  
pp. 23
Author(s):  
Nor Aziyah Bakhari ◽  
Siti Nur Amirah Diana Fadzillah ◽  
Norain Isa
Keyword(s):  
Blood Pressure ◽  
Petroleum Ether ◽  
Silica Gel ◽  
1H Nmr ◽  
Column Chromatography ◽  
Mobile Phase ◽  
Spectroscopic Data ◽  
Chemical Constituents ◽  
Ethanol Extract ◽  
First Time

Tinospora crispa Miers (Menispermaceae) is a climbing vine with stems rich in warts. The plant is called Akar Seruntum or Patawali in Malaysia and is widely used for treating skin complaints, malaria, bacterial abscess, high blood pressure and diabetes. In the present study, the stems of T. crispa were collected from the locality and succesively extracted with petroleum ether, followed by chloroform and ethanol. The insecticidal active extract (ethanol extract) was  subjected to column chromatography of silica gel eluted with a gradient mobile phase containing hexane, chloroform and ethanol. Among the chemical constituents isolated are n-tetracosyl trans-ferulate and n-octacosyl alcohol, along with three known aporphine alkaloids; N-formylnornuciferine, N-acetylnornuciferine and lysicamine. All compounds were identified by comparing their spectroscopic data (UV, IR, 1H NMR, MS) with data from corresponding values in the literature. Isolation of n-tetracosyl trans-ferulate and n-octacosyl alcohol is reported the first time for T. crispa.

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