vii
TABLE OF CONTENTS
CHAPTER
1
2
TITLE
PAGE
DECLARATION
ii
ACKNOWLEDGEMENT
iv
ABSTRACT
v
TABLE OF CONTENTS
vii
LIST OF TABLES
xi
LIST OF FIGURES
xiii
LIST OF SYMBOLS
xvii
LIST OF APPENDICES
xviii
INTRODUCTION
1.1
General Introduction
1
1.2
Research Background
2
1.3
Problem Statement
3
1.4
Research Objectives
5
1.5
Scope of Study
5
LITERATURE REVIEW
2.1
Friedel Crafts Alkylation of Aromatic Compounds
6
2.2
Mesoporous Materials
8
2.2.1
Mesoporous MCM-41 Molecular Sieves
8
2.2.2
Mechanisms of Formation for MCM-41
11
2.3
Incorporation of Aluminium into MCM-41
12
viii
2.4
Catalytic Applications of MCM-41
2.5
Characterization Techniques
2.5.1
Fourier Transform Infrared Spectroscopy
16
2.5.2
Powdered X-ray Diffraction Measurement
17
2.5.3
Magic Angle Spinning-Nuclear Magnetic
Resonance (MAS NMR) Spectroscopy
2.5.4
Temperature Programmed Desorption of
Ammonia (TPD-NH3)
2.6.2
22
Pyridine Adsorption – Fourier Transformed
Infrared Spectroscopy Measurement
23
Quantitative Analysis of Hydroxyalkylation of
Benzene with Propylene Oxide
3
21
Surface Acidity Measurement
2.6.1
2.7
19
Nitrogen Adsorption and Desorption
Measurement
2.6
15
25
EXPERIMENTAL
3.1
Synthesis of Mesoporous MCM-41
3.1.1
Synthesis of Purely Siliceous MCM-41
(Si-MCM-41)
3.1.2
3.1.3 Preparation of H-Al-MCM-41
28
29
Characterization of Mesoporous MCM-41
3.2.1
X-ray Diffraction Measurement
30
3.2.2
Surface Area Measurement
30
3.2.3
Fourier Transform Infrared Spectroscopy
30
3.2.4
Solid State Nuclear Magnetic Resonance
Spectroscopy
3.3
27
Synthesis of Aluminated MCM-41
(Al-MCM-41)
3.2
27
31
Acidity Studies of Mesoporous MCM-41
3.3.1
Temperature Programmed Desorption of
Ammonia
3.3.2
Pyridine Adsorption – Fourier Transformed
31
ix
Infrared Spectroscopy Measurement
3.4
32
Catalytic Activity of Mesoporous MCM-41 in
Hydroxyalkylation of Benzene with Propylene Oxide
3.5
3.4.1 Activation of Catalysts
32
3.4.2
33
Catalytic Reaction Procedure
Most Favourable Condition of Model Reaction
34
3.5.1
SiO2:Al2O3 Ratio
34
3.5.2
Temperature
34
3.5.3
Time on Stream
34
3.5.4
Reactant Mole Ratio Composition
34
3.5.5 Solvent
36
3.5.6
36
Autoclave Reactor
3.6
Reusability of Catalysts
36
3.7
Characterization of Hydroxyalkylation of Benzene
36
with Propylene Oxide Reaction
4
RESULTS AND DISCUSSION
4.1
X-ray Diffraction Analysis
38
4.2
Fourier Transformed Infrared Spectrum Analysis
43
4.3
Magic Angle Spinning Nuclear Magnetic Resonance
(MAS NMR)
4.3.1.
27
Al MAS NMR
47
4.3.2
29
Si MAS NMR
49
4.4
Nitrogen Adsorption and Desorption Analysis
4.5
Pyridine Adsorption – Fourier Transformed Infrared
Spectroscopy Measurement
4.6
4.9
61
Catalytic Activity of Mesoporous MCM-41 in
Friedel Crafts Reaction
4.8
54
Temperature Programmed Desorption of Ammonia
(TPD-NH3)
4.7
53
63
Determination of Amount of Desired Product
(2-phenyl-1-propanol)
65
Effect of SiO2 : Al2O3 Ratios
66
x
4.10
Effect of Temperature
68
4.11
Effect of Propylene Oxide : Benzene Mole Ratio
70
4.12
Effect of Reaction Time
71
4.13
Effect of Solvent
73
4.14
Effect of Autogenous Pressure
74
4.15
Reusability of Al-MCM-41
75
4.16
Proposed Mechanism of Hydroxyalkylation
of Benzene with Propylene Oxide Catalyzed
Al-MCM-41
5
78
CONCLUSIONS AND RECOMMENDATIONS
5.1
Conclusions
81
5.2
Recommendations
83
REFERENCES
84
APPENDICES
91
xi
LIST OF TABLES
TABLE NO.
TITLE
2.1
Type of M41S mesoporous material
3.1
Sample Codes for Al-MCM-41 with different
SiO2: Al2O3 ratios
3.2
Operation Parameters for Gas Chromatography Flame
4.3
40
Some properties of Si-MCM-41 and Al-MCM-41
Wave number (cm ) of IR spectra of Al-MCM-41
Si MAS NMR
54
Number of acid sites (µmol pyridine g-1) in
H-Al-MCM-41 samples
4.8
51
Surface properties of Al-MCM-41 with various
SiO2:Al2O3 ratios
4.7
49
Calculated peak distribution and Si/Al ratio from
29
4.6
45
Quantitative peak intensities of 27Al MAS NMR of
Al-MCM-41 samples
4.5
42
-1
samples with various SiO2:Al2O3 ratios
4.4
37
The degree of crystallinity of samples with various
SiO2:Al2O3 ratios
4.2
37
Operation Parameters for Gas Chromatography-Mass
Spectroscopy (GC-MS)
4.1
9
29
Ionization Detector (GC-FID)
3.3
PAGE
60
Ratio of Brønsted (B) to Lewis (L) acidity in the
H-Al-MCM-41samples at different desorption temperatures 60
4.9
Amount gas adsorbed of various H-Al-MCM-41
4.10
Gas Chromatography data for hydroxyalkylation of
61
xii
propylene oxide with benzene
4.11
63
The effect of temperature on the conversion and yield of
desired product using Dir-Al-MCM-41 (10) at constant
parameter (Reactant Mole Ratio: 0.5; Time: 24 hours;
Solvent: Nitrobenzene)
4.12
69
Effect of propylene oxide : benzene mole ratio on
hydroxyalkylation of benzene with propylene oxides over
Dir-Al-MCM-41 (10) at constant parameter (Temperature:
393 K; Time: 24 hours; Solvent: Nitrobenzene)
4.13
70
Effect of solvent on hydroxyalkylation of benzene with
propylene oxides over Dir-Al-MCM-41 (10) at constant
parameter (Temperature: 393 K; Reactant Mole Ratio:
0.5; Time: 24 hours)
4.14
74
Effect of autogenous pressure on hydroxylakylation of
benzene with propylene oxide at 393 K over
Dir-Al-MCM-41(10) at constant parameter
(Temperature: 393 K; Reactant Mole Ratio: 0.5; Time:
24 hours; Solvent: Nitrobenzene)
4.15
75
Reusability of Dir-Al-MCM-41 (10) at 393 K at
constant parameter (Temperature: 393 K; Reactant Mole
Ratio: 0.5; Time: 24 hours; Solvent: Nitrobenzene)
76
xiii
LIST OF FIGURES
FIGURE NO.
TITLE
PAGE
2.1
The mesoporous M41S family [30]
10
2.2
The structure of mesoporous MCM-41 material [33]
10
2.3
(1) Liquid crystal phase initiated and (2) silicate anion
initiated [34]
2.4
11
Schematic presentation on the generation of Brønsted and
Lewis acid sites with (a) Distorted framework
Tricoordinated Aluminium (b) Extraframework Aluminum
(EFAL) in Al-MCM-41
14
2.5
FTIR spectrum for purely siliceous Si-MCM-41 [53]
18
2.6
Graphical representation of the Bragg equation. The
diffraction of x-rays is interpreted as the reflection on
a set of planes ( h k l ) [51]
18
2.7
29
20
2.8
The most frequently found types of gas physisorption
n
Si chemical shifts of Q units in solid silicates [54]
isotherms: na = amount adsorbed, ms = mass of solid
adsorbent, p = equilibrium pressure, p0 = saturation
vapour pressure [56]
22
2.9
Structure of (a) Pyridine and (b) Pyridinium Ion
23
3.1
Experiment set up for catalytic testing
33
3.2
Flow chart of determining the most favourable procedure
for propylene oxide and benzene
4.1
XRD powder pattern of (a) calcined at 823 K (b)
as synthesized Si-MCM-41
4.2
35
XRD powder pattern of Dir-Al-MCM41 (10) of
39
xiv
(a) calcined (b) as synthesized samples
4.3
XRD powder pattern of Al-MCM-41 with various
(SiO2:Al2O3) ratios
4.4
27
29
50
Nitrogen adsorption isotherm of (a) Dir-Al-MCM41 (10)
(b) Sec-Al-MCM41(0.25 M)
4.11
48
Si MAS NMR spectra of Si-MCM-41 and Al-MCM-41
with various SiO2:Al2O3 ratio
4.10
46
Al MAS NMR spectra of Zeolite A and Al-MCM-41
samples with various SiO2:Al2O3 ratio
4.9
44
FTIR spectra of calcined Al-MCM-41 with various
SiO2:Al2O3 ratios : (a) 10 (b) 20 (c) 40 (d) 80
4.8
44
FTIR spectra of Sec-Al-MCM-41 (a) after (b) before
calcination at 823 K
4.7
42
FTIR spectra of Si-MCM-41 (a) after (b) before
calcination at 823 K
4.6
41
XRD powder pattern of Sec-Al-MCM41 (0.25M)
(a) calcined at 823 K (b) before calcination at 823 K
4.5
39
52
FTIR spectra of hydroxyl region of Dir-Al-MCM41
with SiO2:Al2O3 (a) 10 (b) 20 (c) 40 (d) 80 dehydrated
at 673K under 10-5 mbar pressure
4.12
FTIR spectra of hydroxyl region of Sec-Al-MCM41(0.25 M)
with dehydrated at 673K under 10-5 mbar pressure
4.13
55
55
FTIR spectra of pyridine desorbed on Dir-Al-MCM41 (10)
under vacuum 10-5 mbar pressure at (a) 298K (b) 423K
(c) 523K (d) 673K for every 1 hour
4.14
56
FTIR spectra of pyridine desorbed on Dir-Al-MCM41 (20)
under vacuum 10-5 mbar pressure at (a) 298K (b) 423K
(c) 523K (d) 673K for every 1 hour
4.15
56
FTIR spectra of pyridine desorbed on Dir-Al-MCM41 (40)
under vacuum 10-5 mbar pressure at (a) 298K (b) 423K
(c) 523K (d) 673K for every 1 hour
4.16
57
FTIR spectra of pyridine desorbed on Dir-Al-MCM41 (80)
under vacuum 10-5 mbar pressure at (a) 298K (b) 423K
(c) 523K (d) 673K for every 1 hour
57
xv
4.17
FTIR spectra of pyridine desorbed on Sec-Al-MCM-41
(0.25M) under vacuum 10-5 mbar pressure at (a) 298K
(b) 423K (c) 523K (d) 673K for every 1 hour
4.18
58
Temperature Programmed Desorption of Ammonia
(TPD-NH3) spectra of H-Al-MCM-41 of Dir-Al-MCM41
of (a) 10 (b) 20 (c) 40 (e) 80 (d) Sec-Al-MCM-41(0.25M)
4.19
Chromatogram of liquid product hydroxyalkylation of
benzene with propylene oxide without catalyst at 363 K
4.20
62
64
Chromatogram of liquid product hydroxyalkylation of
benzene with propylene oxide using Dir Al-MCM41 (10)
at 363 K after 3 hours
4.21
Calibration Curve of Standard with Internal Standard
(Toluene 2.0 M in Nitrobenzene)
4.22
64
65
Conversion of benzene and Selectivity of product (%)
with various SiO2:Al2O3 ratio at constant parameter
(Temperature: 363 K; Reactant Mole Ratio: 0.5; Time:
24 hours; Solvent: Nitrobenzene)
4.23
67
Amount of 2-phenyl-1-propanol (desired product) (mmol)
with various SiO2:Al2O3 ratio at constant parameter
(Temperature: 363 K; Reactant Mole Ratio: 0.5; Time:
24 hours; Solvent: Nitrobenzene)
4.24
68
Effect of temperature on the conversion and selectivity
of product using Dir-Al-MCM41 (10) at constant
parameter (Reactant Mole Ratio: 0.5; Time: 24 hours;
Solvent: Nitrobenzene)
4.25
69
The effect of reaction time on benzene conversion over
Dir-Al-MCM-41 (10) at constant parameter (Temperature:
393 K; Reactant Mole Ratio: 0.5; Solvent: Nitrobenzene)
4.26
72
The effect of reaction time on selectivity and oligomerisation
of propylene oxides over Dir-Al-MCM-41 (10) at constant
parameter (Temperature: 393 K; Reactant Mole Ratio: 0.5;
Solvent: Nitrobenzene)
4.27
72
X-ray diffractogram patterns of H-Dir-Al-MCM41 (10)
during three recycles
77
xvi
4.28
Proposed mechanism for Al-MCM-41 catalyzed
hydroxyalkylation of aromatics with propylene oxides
79
xvii
LIST OF SYMBOLS
B/L ratio
-
Brønsted acid sites to Lewis acid sites ratio
BET
-
Brunnauer, Emmett and Teller
Cu Kα
-
X-ray diffraction from Copper K energy levels
FTIR
-
Fourier Transform Infrared Spectroscopy
GC-MS
-
Gas Chromatography- Mass Spectroscopy
h
-
Hour
IS
-
Internal Standard
IUPAC
-
International Union of Pure and Applied Chemistry
KBr
-
Potassium Bromide
MAS NMR
-
Magic-Angle-Spinning Nuclear Magnetic Resonance
N2
-
Nitrogen
OH
-
Hydroxyl
P/Po
-
Relative pressure; obtained by forming the ratio of the
equilibrium pressure and vapour pressure Po of the adsorbate
at the temperature where the isotherm is measured
SiO2: Al2O3
-
Silica to Alumina ratio
SiO4
-
Siliceous; framework silicon in zeolite
T
-
Reaction Temperature
TO4
-
Tetrahedral unit where T= Al or Si
XRD
-
X-ray Diffraction technique
λ
-
Wavelength
2θ
-
Bragg Angle
xviii
LIST OF APPENDICES
APPENDIX
TITLE
A
Mass spectra of 2-phenyl-1-propanol
B
Chromatograms of reactant (a) benzene (b) propylene
PAGE
91
oxide (c) nitrobenzene as a solvent
92
C
Nitrogen Adsorption Isotherm
94
D
Calculation method of Conversion, Selectivity, Yield
and Percentage of Oligomerisation
96