the aerobic oxidation of alcohols bi doped ceo2 oxide
Post on 20-Feb-2022
8 Views
Preview:
TRANSCRIPT
Supporting Information
Bi Doped CeO2 Oxide Supported Gold Nanoparticle Catalysts for the Aerobic Oxidation of Alcohols
Chiranjit Santra,a Aline Auroux,b and Biswajit Chowdhury*a
1. Department of Applied Chemistry, Indian School of Mines, Dhanbad, India2. Institut de Recherches sur la Catalyse et l'Environnement de Lyon, UniversitΓ© Lyon1,
France
*Corresponding author: biswajit_chem2003@yahoo.com; Tel: (+91)-326-2235663; Fax: (+91)-326-2296563
Micro kinetic analysis: The criteria below must be met for the reaction rates to be free from
mass transfer limitations [a-c]:
(a) Gas-liquid mass-transfer resistance is considered insignificant if
πΌ1 =π π2
πΎ1πππΆ βπ΄
< 0.1 β¦β¦β¦β¦β¦β¦β¦β¦β¦(1)
πΎ1ππ = (1.48 Γ 10 β 3)(π)2.18(ππ
ππ)1.88(ππ
ππ‘)2.16(βπ
β2)1.16β¦β¦β¦β¦β¦(2)
(b) Liquid-solid mass-transfer limitation is considered unimportant if
πΌ2 =π π2
πΎπ πππΆ βπ΄
< 0.1 β¦β¦β¦β¦β¦β¦β¦β¦β¦(3)
ππ =6π€
ππππβ¦β¦β¦β¦β¦β¦β¦β¦β¦(4)
πΎπ ππ
π·ππΉπ= 2 + 0.4[π(ππ)4π3
1
π31
]0.25[ π1
π1π·π]0.333 β¦β¦β¦β¦β¦β¦β¦(5)
FC assumed 1 for spherical particles
π·π =(7.4 Γ 10 β 8)π(πππ€)
12
πππ£0.6π
β¦β¦β¦β¦β¦β¦β¦(6)
π =πππ3π5
ππ
ππππ β¦β¦β¦β¦β¦β¦β¦(7)
π = 1.0 β 1.26[ ππ
ππ3π] πππ [ ππ
ππ3π] < 3.5 Γ 10 β 2 β¦β¦β¦β¦β¦β¦(8)
π = 0.62 β 1.85[ ππ
ππ3π] πππ [ ππ
ππ3π] > 3.5 Γ 10 β 2 β¦β¦β¦β¦β¦β¦(9)
ππ = ππππ₯ππΏππ β¦β¦β¦β¦β¦β¦β¦β¦(10)
Electronic Supplementary Material (ESI) for RSC Advances.This journal is Β© The Royal Society of Chemistry 2016
ππ =ππ
=π πππ2
β¦β¦β¦β¦β¦β¦β¦β¦β¦(11)
(c) Pore diffusion resistance can be considered to be insignificant if
Ξ¦ππ₯π =ππ
6 [(π + 1)πππ π2
2π·ππ€πΆ βπ΄
]1/2 < 0.2 β¦β¦β¦β¦β¦β¦(12)
π·π = π·π(ππ)β¦β¦β¦β¦β¦β¦(13)
Porosity and tortuosity can be assumed 0.40-0.50 and 3, respectively; m can be assumed to be
1, unless experimentally determined.
If gas-liquid mass-transfer limitation is significant, is replaced by CAS which is calculated πΆ βπ΄
by using the formula
πΆπ΄π = πΆ βπ΄ β
π π2
[ 1πΎπππ
+1
πΎπ ππ] β 1
β¦β¦β¦β¦β¦β¦β¦(14)
List of Symbols= Gas-liquid interfacial area per unit volume of reactor, m2/m3ππ
= Liquidβsolid interfacial area, m-1ππ
= Saturation solubility of O2 in liquid phase, kmol/m3πΆ βπ΄
CAS = O2 concentration on the catalyst surface, kmol/m3
De = Effective diffusivity, m2/sdi = Impeller diameter, mDM = Molecular diffusivity, m2/sdp = Particle diameter, mdt = Reactor diameter, mHe = Henryβs law constant, kmol/m3/atmhl = Height of the first impeller from the bottom, mh2 = Height of the liquid, mKl = Liquid film mass-transfer coefficient, m/s
= Overall gas-liquid mass-transfer coefficient, s-1πΎπππ
Ks = Liquid-solid mass-transfer coefficient, m/sm = Order of reaction with respect to oxygenMw = Molecular weight of solvent, g/moln = Moles of gas at constant pressure, kmolN = Agitation speed, HzNp = Power number
= Partial pressure of oxygen, MPaππ
R = Universal gas constant, kJ/kmol/K= Overall rate of oxidation, (kmol/m3)s-1π π2
rmax = Maximum rate of hydrogenation, (kmol/m3)s-1
T = Temperature, KVg = Volume of the gas in the reactor, m3
Vl = Volume of the liquid in the reactor, m3
W = Catalyst loading, kg/m3
Greek Letters = Parameter defined by Eq. 1πΌ1
= Parameter defined by Eq. 3πΌ2
= Parameter defined by Eq. 12Ξ¦ππ₯π
= Density of liquid, kg/m3ππ
= Viscosity of liquid, centipoiseππ
= Association factorπ
= Molar volume of the solute, cm3/molππ
= Density of particle, kg/m3ππ
= Porosity of the catalyst particleπ = Tortuosityπ
Fig. S1 Adsorption/desorption isotherms and pore size distribution of the supports: (a) CeO2, (b) Bi(2 mol%)-CeO2, (c) Bi(4 mol%)-CeO2, (d) Bi(6 mol%)-CeO2, and (e) Bi(8 mol%)-CeO2.
Fig. S2 Adsorption/desorption isotherms and pore size distribution for 3.5 wt% of (a) Au/CeO2, (b) Au/Bi(2 mol%)-CeO2, (c) Au/Bi(4 mol%)-CeO2, (d) Au/Bi(6 mol%)-CeO2, and (e) Au/Bi(8 mol%)-CeO2.
Fig. S3 HRTEM images of 3.5 wt% nominal gold loading on (a) Au/Bi(2 mol%)-CeO2 and (b) Au/CeO2.
Fig. S4 Bi(4f) core level XPS spectra of Au(3.5 wt%)/Bi(6 mol%)-CeO2 catalyst.
Fig. S5 Ce(3d) core level XPS spectra of (a) CeO2, (b) Bi(2 mol%)-CeO2, (c) Bi(4 mol%)-CeO2, (d) Bi(6 mol%)-CeO2, (e) Bi(8 mol%)-CeO2, (f) Au(3.5wt%)/CeO2, and (g) Au(3.5wt%)/Bi(6 mol%)-CeO2.
Fig. S6 CO2-TPD traces of (a) Au(3.5 wt%)/CeO2 and (a) Au(3.5 wt%)/Bi(4 mol%)-CeO2 catalysts. Here regions 1, 2, and 3 represent weak, medium, and strong basic sites respectively.
Table S7 Quantitative analysis of CO2-TPD of the following catalysts.
Sample Volume of CO2(cm3 g-1 STP )
Bi(4 mol%)-CeO2 1.285Bi(6 mol%)-CeO2 1.150Bi(8 mol%)-CeO2 0.683Au(3.5 wt%)/CeO2 0.893Au(3.5 wt%)/Bi(4 mol%)-CeO2 1.300Au(3.5 wt%)/Bi(6 mol%)-CeO2 1.726
Table S8 Summary of BET surface area and porosity results of doped Au/Bi(6 mol%)-CeO2 with different gold loading.
Sample Surface area(m2g-1)
Pore size(nm)
Pore volume(cc g-1)
1 wt% Au/Bi-CeO2 18.53 10.80 0.0502.33 wt% Au/Bi-CeO2 16.90 11.21 0.0473.5 wt% Au/Bi-CeO2 15.53 12.98 0.0504 wt% Au/Bi-CeO2 15.22 10.98 0.044
Table S9 Aerobic oxidation of benzyl alcohol to benzaldehyde (selectivity >99% in each case) over Au(3.5 wt% )/Bi(6 mol %)-CeO2 catalyst at different temperature.
Temperature (oC)
Conversion (%)
60 12.490 39.1120 63.1130 42.8
Reaction condition: Toluene solvent, 4 cm3; alcohol, 4 mmol; catalyst, 0.1 g; O2, 50 std cm3 min-1; temperature 110 oC; reaction time, 3 h; ambient pressure; dodecane used as an internal standard.
Fig. S10 Initial conversion rates dependence on reaction temperature with Au(3.5 wt%)/Bi(6 mol %)-CeO2. Initial rates derived from transient conversion rates extrapolated to residence time zero.
Oxygen solubility calculation: Oxygen solubility in methanol, ethanol, water and toluene
used as solvent for the benzyl alcohol oxidation reaction were calculated from the
experimental data provided in literature.1-4 We have calculated vapour pressure (bar) of the
solvent at desired temperature by using equation, where A, B, C are log10 π = π΄ β {
π΅π + πΆ
}
Antoine equation parameters and T is temperature (K). A plot was drawn with oxygen
concentration (mol/m3) vs partial pressure of oxygen (MPa). With the help of slope and
intercept of the plot, we can calculate the solubility of the oxygen in that particular solvent at
that specific temperature. In case of solvent free conditions, we calculate solubility of oxygen
in benzyl alcohol by Hansenβs solubility parameters (HSPs). The HSPs of benzyl alcohol
oxygen were taken from Hansenβs 1971 parameters listed in Handbook of Solubility
Parameters4, where Ξ΄d= 6.7 MPa1/2, Ξ΄p = 0.0 MPa1/2, Ξ΄h = 3.8 MPa1/2, and Ξ΄t= 7.7 MPa1/2. The
HSPs of oxygen; oxygen were taken from literature.4 Further the distance between the HSPs
of two substances in the three-dimensional (3D)-HSP diagram can be calculated as formula
mentioned below.5
The relationship between Ra and logxG for oxygen is taken as equation below6
Further with the help Henry low, we calculate the concentration of oxygen at desired
pressure.
Reference
1 Geng, M.; Duan, Z. Geochim. Cosmochim. Acta, 2010, 74, 5631β5640.
2 Li, A.; Tang, S.; Tan, P.; Liu, C.; Liang, B. J. Chem. Eng. Data, 2007, 52, 2339β2344.
3 Fischer, K. J. Chem. Thermodynamics, 2001, 33, 1285β1308.
4 Barton, A. F. M. Handbook of Solubility Parameters CRC Press, 1983, 153-157.
5 Sato, T.; Hamada, Y.; Sumikawa, M.; Araki, S.; Yamamoto, H. Ind. Eng. Chem. Res., 2014, 53, 19331β19337.
top related