Nanometer size pores in ionic liquid loaded silica gel characterized by positron lifetime spectroscopy

2015 ◽  
Vol 213 (1) ◽  
pp. 165-169 ◽  
Author(s):  
Christian Herold ◽  
Hubert Ceeh ◽  
Thomas Gigl ◽  
Markus Reiner ◽  
Marco Haumann ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Silica Gel ◽  
Positron Lifetime ◽  
Nanometer Size ◽  
Positron Lifetime Spectroscopy

Defects in electron irradiated GaP studied by positron lifetime spectroscopy

1995 ◽  
Vol 60 (6) ◽  
pp. 541-544 ◽  
Author(s):  
A. Polity ◽  
Th. Abgarjan ◽  
R. Krause-Rehberg
Keyword(s):  
Positron Lifetime ◽  
Positron Lifetime Spectroscopy

Study of Compensation Defects and Electron Irradiation-Induced Defects in Undoped SI-InP by Positron Lifetime Spectroscopy

2008 ◽  
Vol 607 ◽  
pp. 134-136
Author(s):  
Y.J. Zhang ◽  
Ai Hong Deng ◽  
You Wen Zhao ◽  
J. Yu ◽  
X.X. Yu ◽  
...  
Keyword(s):  
Electron Irradiation ◽  
Positron Lifetime ◽  
Deep Level ◽  
High Concentration ◽  
Positron Annihilation Lifetime ◽  
Donor Type ◽  
Positron Lifetime Spectroscopy ◽  
Transient Spectroscopy ◽  
Induced Defects ◽  
Irradiation Induced Defects

Positron annihilation lifetime (PAL) spectroscopy，photo-induced current transient spectroscopy (PICTS) and thermally stimulated current (TSC) have been employed to study the formation of compensation defects and their evolvement under iron phosphide (IP) ambience or pure phosphide (PP) ambience. In the formation of IP SI-InP, the diffusion of Fe atoms suppresses the formation of some open-volume defects. As to PP SI-InP, VInH4 complexes dissociate into acceptor vacancies VInHn(n-3)(n=0,1,2,3), which compensate residual donor type defects and make the sample semi-insulating. Electron irradiation-induced deep level defects have been studied by TSC in PP and IP SI-InP, respectively. In contrast to a high concentration of irradiation-induced defects in as-grown and PP annealed InP, IP SI-InP has a very low concentration of defects.

Efficient and Reusable Silica Gel Supported Metal Ionic Liquid Catalysts for Palmitic Acid Esterification to Biodiesel

2021 ◽  
Vol 43 (1) ◽  
pp. 1-1
Author(s):  
Guo Yingwei Guo Yingwei ◽  
Chen Xuedan Chen Xuedan ◽  
Yan Shiting Yan Shiting ◽  
Zhang Zhengliang Zhang Zhengliang ◽  
Chen Yuqin Chen Yuqin ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Palmitic Acid ◽  
Silica Gel ◽  
High Surface ◽  
High Surface Area ◽  
Kinetic Studies ◽  
Catalytic Performance ◽  
Reaction Conditions ◽  
Acid Esterification ◽  
Supported Metal

A series of silica gel (SG) supported metal ionic liquid catalysts (x[Bmim]Cl-CrCl3/SG) were synthesized and exploited for the esterification of palmitic acid (PA) with methanol (ML) to produce biodiesel efficiently. The 10%[Bmim]Cl-CrCl3/SG catalyst with high surface area and desirable acidity exhibited the best catalytic performance and reusability after six consecutive running cycles. Based on the response surface analysis, the optimal reaction conditions were obtained as follows: methanol/acid mole ratio = 11:1 mol/mol, catalyst amount = 5.3 wt%, reaction time = 65 min, as well as reaction temperature = 373 K, reaching to a biodiesel yield of 96.1%. Further kinetic studies demonstrated that the esterification of PA with ML obeyed 1.41 order kinetics for acid concentration with the activation energy of 16.88 kJ/mol

Structure of nanometer-sized polycrystalline iron investigated by positron lifetime spectroscopy

1988 ◽  
Vol 38 (14) ◽  
pp. 9545-9554 ◽  
Author(s):  
H.-E. Schaefer ◽  
R. Würschum ◽  
R. Birringer ◽  
H. Gleiter
Keyword(s):  
Positron Lifetime ◽  
Polycrystalline Iron ◽  
Positron Lifetime Spectroscopy

Two Types of Lamellar Phase in TTAB/Water/Pentanol System as Detected by Positron Lifetime Spectroscopy

2004 ◽  
Vol 445-446 ◽  
pp. 316-318
Author(s):  
P.H. Khani ◽  
R. Yadav ◽  
K. Chandramani Singh ◽  
P.C. Jain
Keyword(s):  
Positron Lifetime ◽  
Lamellar Phase ◽  
Positron Lifetime Spectroscopy

Positron lifetime spectroscopy in ordered nanoporous polymers

2013 ◽  
Vol 51 (15) ◽  
pp. 1157-1161 ◽  
Author(s):  
Jason Engbrecht ◽  
David Green ◽  
Marc A. Hillmyer ◽  
David Olson ◽  
Eric M. Todd
Keyword(s):  
Positron Lifetime ◽  
Nanoporous Polymers ◽  
Positron Lifetime Spectroscopy

scholarly journals Zinc Acetate Immobilized on Mesoporous Materials by Acetate Ionic Liquids as Catalysts for Vinyl Acetate Synthesis

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Hang Xu ◽  
Tianlong Yu ◽  
Mei Li
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Vinyl Acetate ◽  
Silica Gel ◽  
Catalyst Activity ◽  
Catalyst Layer ◽  
Space Velocity ◽  
Molar Ratio ◽  
Vinyl Acetate Monomer ◽  
Adsorption Desorption

Ionic liquid containing active ingredient Zn(CH3COO)2was loaded in mesoporous silica gel to form supported ionic liquids catalyst (SILC) which was used to synthesize vinyl acetate monomer (VAM). SILC was characterized by1HNMR, FT-IR, TGA, BET, and N2adsorption/desorption and the acetylene method was used to evaluate SILC catalytic activity and stability in fixed reactor. The result shows that 1-allyl-3-acetic ether imidazole acetate ionic liquid is successfully fixed within mesoporous channel of silica gel. The average thickness of ionic liquid catalyst layer is about 1.05 nm. When the catalytic temperature is 195°C, the acetic acid (HAc) conversion is 10.9% with 1.1 g vinyl acetate yield and 98% vinyl acetate (VAc) selectivity. The HAc conversion is increased by rise of catalytic temperature and molar ratio of C2H2 : HAc and decreased by mass space velocity (WHSV). The catalyst activity is not significantly reduced within 7 days and VAc selectivity has a slight decrease.

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