Mesoporous Titanosilicate Molecular Sieves Prepared at Ambient Temperature by Electrostatic (S+I-, S+X-I+) and Neutral (S°I°) Assembly Pathways:  A Comparison of Physical Properties and Catalytic Activity for Peroxide Oxidations

1996 ◽  
Vol 118 (38) ◽  
pp. 9164-9171 ◽  
Author(s):  
Wenzhong Zhang ◽  
Michael Fröba ◽  
Jialiang Wang ◽  
Peter T. Tanev ◽  
Joe Wong ◽  
...  
1930 ◽  
Vol 34 (4) ◽  
pp. 748-752 ◽  
Author(s):  
G. B. Taylor ◽  
G. B. Kistiakowsky ◽  
J. H. Perry

2007 ◽  
Vol 21 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Cláudio Maniglia-Ferreira ◽  
Eduardo Diogo Gurgel-Filho ◽  
João Batista Araújo Silva Jr ◽  
Regina Célia Monteiro de Paula ◽  
Judith Pessoa Andrade Feitosa ◽  
...  

This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also seeked to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130°. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130°C causes changes to its chemical structure which permanently alter its physical properties.


2019 ◽  
Vol 43 (2) ◽  
pp. 813-819 ◽  
Author(s):  
Ravi Shankar ◽  
Asmita Sharma ◽  
Bhawana Jangir ◽  
Manchal Chaudhary ◽  
Gabriele Kociok-Köhn

The synthesis of 1,1,3,3-tetraorganodisiloxanes from the hydrolytic oxidation of diorganosilanes, RR1SiH2, using AuNPs as an interfacial catalyst is described. This study provides a manifestation of the photothermal effect in enhancing the catalytic activity at ambient temperature.


2001 ◽  
Vol 171 (1-2) ◽  
pp. 229-241 ◽  
Author(s):  
Rodica Tismaneanu ◽  
Biswajit Ray ◽  
Rafael Khalfin ◽  
Rafi Semiat ◽  
Moris S. Eisen

2020 ◽  
Vol 7 (5) ◽  
pp. 1140-1147
Author(s):  
Chao Liu ◽  
Li Yang ◽  
Jiaxu Zhang ◽  
Jianmin Sun

A heterogeneous Co-modified pyridinecarboxaldehyde-polyethylenimine catalyst with active metal sites and amine groups exhibited high catalytic activity for CO2 conversion under mild conditions, even at ambient temperature.


Catalysts ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1223
Author(s):  
James K. Aldridge ◽  
Louise R. Smith ◽  
David J. Morgan ◽  
Albert F. Carley ◽  
Mandy Humphreys ◽  
...  

A series of Pt-based catalysts were synthesised and investigated for ambient temperature CO oxidation with the aim to increase catalytic activity and improve moisture resistance through support modification. Initially, bimetallic PtPd catalysts supported on alumina were found to exhibit superior catalytic activity compared with their monometallic counterparts for the reaction. Following an investigation into the effect of Pt/Pd ratio, a composition of 0.1% Pt/0.4% Pd was selected for further studies. Following this, SnO2/Al2O3 supports were synthesised from a variety of tin oxide sources. Catalytic activity was improved using sodium stannate and tin oxalate precursors compared with a traditional tin oxide slurry. Catalytic activity versus tin concentration was found to vary significantly across the three precursors, which was subsequently investigated by X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectroscopy (EDX).


1983 ◽  
Vol 170 (2) ◽  
pp. 447-469 ◽  
Author(s):  
Philip Serwer ◽  
Robert H. Watson ◽  
Shirley J. Hayes ◽  
Jerry L. Allen

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