A Study of Ethanol Reactions over Pt/CeO2 by Temperature-Programmed Desorption and in Situ FT-IR Spectroscopy: Evidence of Benzene Formation

2000 ◽  
Vol 191 (1) ◽  
pp. 30-45 ◽  
Author(s):  
Anna Yee ◽  
Scott J. Morrison ◽  
Hicham Idriss
Author(s):  
Xi Yang

The interfacial polymerization (IP) of piperazine (PIP) and trimesoyl chloride (TMC) has been extensively utilized to synthesize the nanofiltration (NF) membrane. However, it is still a huge challenge to monitor the IP reaction, because of the fast reaction rate and the formed ultra-thin film. Herein, two effective strategies are applied to reduce the IP reaction rate: (1) the introduction of hydrophilic interlayers between the porous substrate and the formed polyamide layer; (2) the addition of macromolecular additives in the aqueous solution of PIP. As a result, in-situ FT-IR spectroscopy was firstly used to monitor the IP reaction of PIP/TMC reaction system, with hydrophilic interlayers or macromolecular additives. Moreover, we study the formed polyamide layer growth on the substrate, in a real-time manner. The in-situ FT-IR experimental results confirm that the IP reaction rates are effectively suppressed and the formed polyamide thickness reduces from 138±24 nm to 46±2 nm. Furthermore, the optimized NF membrane with excellent performance are consequently obtained, which include the boosted water permeation flux about 141~238 (L·m2·h/MPa) and superior salt rejection of Na2SO4 > 98.4%.


2012 ◽  
Vol 14 (7) ◽  
pp. 2239 ◽  
Author(s):  
Caterina Barzan ◽  
Elena Groppo ◽  
Elsje Alessandra Quadrelli ◽  
Vincent Monteil ◽  
Silvia Bordiga

2019 ◽  
Vol 3 (1) ◽  
pp. 34 ◽  
Author(s):  
Nataliia Nastasiienko ◽  
Borys Palianytsia ◽  
Mykola Kartel ◽  
Mats Larsson ◽  
Tetiana Kulik

The studies of pyrolysis of caffeic acid (CA) and its surface complexes is important for the development of technologies of heterogeneous catalytic pyrolysis of plant- and wood- based renewable biomass components. In this work, the structure and thermal transformations of the surface complexes of CA on the surface of nanoceria were investigated using Fourier transform–infrared (FT–IR) spectroscopy, thermogravimetric analysis (TGA) and temperature-programmed desorption mass spectrometry (TPD MS). It was found that CA on the surface of cerium dioxide forms several types of complexes: bidentate carboxylates, monodentate carboxylates and complexes formed as a result of interaction with phenolic hydroxyl groups. This is due to the ability of nanosized cerium dioxide to generate basic hydroxyl groups that can deprotonate phenolic groups to form phenolates on the surface. The main pyrolysis products were identified. The possible ways of forming 3,4-dihydroxyphenylethylene, acetylene carboxylic acid, pyrocatechol and phenol from surface complexes of CA were suggested. It was established that on the nanoceria surface effectively occur the decarboxylation, decarbonylation, and dehydration reactions of the CA, which are the desirable processes in biomass conversion technologies.


2015 ◽  
Vol 3 (22) ◽  
pp. 11976-11984 ◽  
Author(s):  
Haiyan Mao ◽  
Jun Xu ◽  
Yue Hu ◽  
Yining Huang ◽  
Yang Song

A first high-pressure study on MOF α-Mg3(HCOO)6 probed by in situ vibrational spectroscopy revealed strongly contrasting host-dependent structural transitions and stabilities.


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