vii
TABLE OF CONTENTS
CHAPTER
TITLE
DECLARATION
ii
DEDICATION
iii
ACKNOWLEDGEMENTS
iv
ABSTRACT
v
ABSTRAK
vi
TABLE OF CONTENTS
vii
LIST OF TABLES
xii
LIST OF FIGURES
xv
LIST OF SYMBOLS/ABBREVIATIONS
xxi
LIST OF PUBLICATIONS
1
xxiv
INTRODUCTION
1
1.1 Research Background
5
1.1.1
Porous Manganese Oxide Materials
5
1.1.2
Manganese Oxide Octahedral Molecular Sieves (OMS-2)
7
1.1.3
Modification of OMS-2 Materials
9
1.1.4
Designing of Sulfated Ti-OMS-2 as Bifunctional
Oxidative and Acidic Catalyst
2
PAGE
12
1.2 Research Questions and Scope of the Research
13
1.3 Research Objectives
14
LITERATURE REVIEW
18
2.1
Introduction
18
2.2
Classification of Porous Manganese Oxide
18
viii
2.3
2.4
2.5
Material Synthesis
24
2.3.1 Synthesis of Porous Manganese Oxide
24
2.3.2 Synthesis of OMS-2 Materials
26
Modification of Manganese oxide
29
2.4.1
29
Overview of Modification of OMS-2 materials
2.4.2 Ion Exchange
37
2.4.3 Impregnation
38
2.4.4 Alkylsilylation
39
2.4.5 Sulphation
41
Catalytic Activity
42
2.5.1 Catalytic Activity of OMS-2 Materials
42
2.5.2 Catalytic Oxidation
45
2.5.3 Titanium Incorporated Materials
49
2.5.4
52
Sulphated Metal Oxides as a Solid Acid Catalyst
2.5.5 Synthesis of Diols
3
53
EXPERIMENTAL
55
3.1
Synthesis of OMS-2 Materials
55
3.1.1 Synthesis of OMS-2 without Buffer (OMS-2a)
57
3.1.2 Synthesis of OMS-2 with buffer (OMS-2b)
57
Modification of OMS-2 materials
57
3.2.1 Synthesis of Metal Substituted OMS-2 (M-OMS-2)
57
3.2.2 Ion Exchange of OMS-2 and M-OMS-2 Samples
58
3.2.3
Synthesis of Ti Incorporated OMS-2 (Ti-OMS-2)
59
3.2.4
Synthesis of Ti Impregnated OMS-2 [Ti-OMS-2 (imp)] 59
3.2
3.2.5 Preparation of TiO2-OMS-2 (mix)
3.2.6 Synthesis of Sulphated Ti-OMS-2
3.3
59
(SO42-/Ti-OMS-2)
60
3.2.7 Surface Modification by Alkylsilylation
60
Characterization Techniques
60
3.3.1 X-Ray Diffraction (XRD) Spectroscopy
61
3.3.2 Atomic Absorption Spectroscopy (AAS)
62
3.3.3 Fourier Transform Infrared (FTIR) Spectroscopy
63
3.3.4 Total Specific Surface Area (BET) and Pore Volume . ...
.....Analysis
65
ix
3.3.5
Thermal Gravimetry and Differential Thermal Analysis
......(TG-DTA)
67
3.3.6 Field Emission Electron Scanning Microscopy (FESEM) 68
3.3.7
Photoluminescence
68
3.3.8 X- Ray Photoelectron Spectroscopy (XPS)
70
3.3.9
71
Pyridine Adsorption
3.3.10 Adsorption Capacity of Adsorbed Water
74
3.3.11 Gas Chromatography (GC) Analysis
74
3.3.12 Gas Chromatography-Mass Spectrometry (GC-MS)
3.4
4
......Analysis
75
Catalytic Testing
75
3.4.1
Oxidation of Benzyl Alcohol
77
3.4.2
Oxidation of Cyclohexane
78
3.4.3
Oxidation of Cyclohexene
79
3.4.4
Oxidation of Styrene
80
3.4.5
Transformation of 1-octene to 1,2-octanediol
81
PHYSICOCHEMICAL PROPERTIES OF OMS-2 AND
MODIFIED OMS-2 CATALYSTS
83
4.1
Introduction
83
4.2
Physicochemical Properties of Prepared OMS-2 by Different
Methods
84
4.3
Physical Properties of Metal Substituted OMS-2 Material
92
4.3
Physical Properties of H-OMS-2 and H-M-OMS-2 Materials
102
4.4
Physicochemical Properties of Ti-OMS-2 Materials
106
4.4.1 Structural Properties of Ti Substituted OMS-2 Catalyst 106
4.4.2 Acidity Properties
113
4.4.3
114
Morphology, Surface Area and Textural Properties
4.4.4 Thermal Stability
4.4.5
119
More Evidence of the Location of Titanium on ...............
.....Ti-OMS-2 Materials
121
4.5
Alkylsilylated of OMS-2 and Ti-OMS-2(0.67)
127
4.6
Sulphated Ti-OMS-2
129
x
5
CATALYTIC ACTIVITY OF OMS-2 AND MODIFIED OMS-2
SAMPLE IN OXIDATION AND ACID REACTIONS
135
5.1
Introduction
135
5.2
Catalytic Activity and Selectivity of OMS-2 and Modified
OMS-2 Samples in Oxidation Reactions
5.2.1
135
Oxidation of Benzyl Alcohol over OMS-2 Prepared by
.....Different Method
5.3.2
135
Oxidation of Cyclohexane over Metals Substituted and
.....Ion.Exchanged OMS-2
5.4.3 Oxidation of Cyclohexene over Ti-OMS-2 Catalyst
140
150
5.4.2 Oxidation of Styrene over Different Location of
.....Titanium sites on Ti-OMS-2 Catalysts
5.3
The Effect of Lewis Acidity in Catalytic Oxidations
5.4
The Role of Different Location of Ti Sites in Ti-OMS-2 in
Oxidation Reactions
5.5
156
157
Catalytic Study on Consecutive Reaction of 1-octene to
1,2-octanediol
6
152
158
SUMMARY AND CONCLUSION
161
6.1
Summary
161
6.2
Conclusion
166
REFERENCES
171
APPENDIXES
189-199
xi
LIST OF TABLES
TABLE NO
1.1
TITLE
PAGE
The synthetic manganese oxides, their natural counterpart and
structures as reported by Suib [12, 20-22].
1.2
2.1
The cations were doped OMS-2 and their location in OMS-2
material.
2.3
2.4
templates.
26
Review of Metal Doped into OMS-2; its synthesis routes, location,
properties, and catalytic application.
30
Some catalytic applications of OMS-2 materials reported in the last
42
Characteristic features of Shell’s epoxidation catalyst compared
with Titanium Silicalite 1.
2.6
19
Synthesis of tunnel and layered manganese oxides with various
decade.
2.5
10
Classification of tunnel and layered manganese oxides and their
crystallographic data [13].
2.2
7
49
The comparisons of the common mild oxidant are used in oxidation
process.
50
3.1
Position of bands and classification for linkages of pyridine.
72
4.1
Effect of potassium concentration in reflux method on the synthesis
of OMS-2.
4.2
The relative intensity and ratio of I(110)/I(200) plane of OMS-2b
and calcined OMS-2b samples calculated by XRD.
4.3
85
88
The ionic radii of metals ion and average crystallite size of OMS-2
and M-OMS-2 samples.
94
xii
4.4
Lattice parameter (a and c) and cell volume (V) of OMS-2 and MOMS-2 samples.
4.5
95
The relative intensity and ratio of I(110)/I(200) plane of OMS-2 and
M-OMS-2 samples.
96
4.6
The physical properties of metal ions.
97
4.7
Source of metal, its charge and their effect to cryptomelane
structure.
98
4.8
AAS data of OMS-2 and M-OMS-2 samples.
99
4.9
The relative intensity and ratio of I(200)/I(211) plane of OMS-2
and M-OMS-2 samples calculated by XRD.
102
4.10
The percentage of potassium substituted by H+.
104
4.11
Chemical composition and physicochemical properties of OMS-2,
Ti-OMS-2 and TiO2–OMS-2.
4.12
107
The lattice parameters (a and c) and cell volume (V) of OMS-2 and
Ti-OMS-2 samples.
109
4.13
Vibrational spectroscopy feature of samples.
111
4.14
The relative intensity and ratio of I(111)/I(211) plane of samples
calculated by XRD.
4.15
116
Binding Energies (eV) of Mn 2p, Ti 2p, and its line separation
(BE) and difference of line separation from selected samples.
122
4.16
Assignments of as-observed IR bands on sulfated samples [154].
131
5.1
Conversion of benzyl alcohol and selectivity to benzaldehyde by
different catalysts.
5.2
136
The relation of amount of potassium exchanged by H+ with
enhancement of % conversion of cyclohexane on H-M-OMS-2
catalyst.
5.3
144
The correlation of Lewis acidity of samples to conversion of
cyclohexane, cyclohexene and styrene.
156
xiii
5.4
The possible role of Lewis acids of catalyst in oxidation of
cyclohexane, cyclohexene and styrene.
157
5.5
The role of Ti sites location in oxidation reaction.
158
6.1
The physicochemical properties-catalytic activity relationship of the
catalysts.
163
xiv
LIST OF FIGURES
FIGURE NO
1.1
TITLE
PAGE
Steps Potential energy diagram for a catalytic reaction (solid
line), i.e. reaction of A and B to form AB, compared with the noncatalytic reaction (dashed line). The presence of a catalyst
lowers the activation energy (Ea) considerably [7].
1.2
Process options in catalytic oxidation and some of their
disadvantages.
1.3
2
3
Crystal structure of cryptomelane-type OMS-2: potassium atoms
are shown as green spheres; MnO6 octahedra are shown in brown.
8
1.4
Mars van Krevelen mechanism.
9
1.5
Partial periodic table showing transition metals that have been
introduced into OMS-2 materials.
10
1.6
Transformation of alkenes to diols via two step reaction.
12
1.7
The schematic of the research approach and research questions.
15
1.8
The significant of the use Ti-OMS-2 in heterogeneous oxidation
and acid reactions.
2.1
Schematic structures of one-dimensional tunnel and layered
manganese oxides [13].
2.2
2.4
22
Intergrowth tunnels of (a) (1×1) and (1×2), and (b) (2×2) and
(2×3) in the tunnel manganese oxides.
2.3
17
23
Transformation reaction from birnessite to hollandite under
hydrothermal conditions.
28
The ion exchange reaction.
37
xv
2.5
Impregnation of porous catalyst.
38
2.6
Chemical structure of OTS.
39
2.7
Mechanism of complete reaction of OTS on the support surface
to form a well ordered layer.
40
2.8
Mechanism of incomplete reaction of OTS on the support surface. 40
2.9
Epoxidation of alkenes using (a) organic peracids, (b) chlorohyrins
route and (c) H2O2 or TBHP as the oxidant.
2.10
47
Epoxidation of propene on Shell catalyst using an organic
peroxide.
50
2.11
Oxidation reactions catalyzed by TS-1.
51
3.1
Materials preparation and their labelling.
56
3.2
The IUPAC classification for adsorption isotherms, where
nad = amount of adsorbed and P/Po= relative pressure.
3.3
The physical process following absorption of a photon by a
molecule.
3.4
69
The mechanism of interaction between pyridine molecules with
Lewis.
3.5
66
73
The interaction between pyridine molecules with Brönsted acid
sites.Catalytic reactions over various modified OMS-2.
73
3.6
Catalytic reactions over various modified OMS-2.
76
4.1
XRD patterns of OMS-2 materials and reference pattern of
Crypromelane, Q JCPDS 29, 1020.
4.2
86
Effect of calcination on XRD patterns of OMS-2b materials, (a)
before calcination, (b) calcination at 400oC, (c) at 500oC, and (d)
at 600oC.
88
4.3
FTIR spectra of (a) OMS-2a and (b) OMS-2b.
89
4.4
Defect on OMS-2 structure.
90
xvi
4.5
Amount of adsorbed water on the surface of OMS-2a and OMS-2b
samples.
90
4.6
TGA plots for OMS-2 materials in N2 atmosphere.
91
4.7
X-ray diffractograms of (a) OMS-2; (b) Ti-OMS-2(0.05); (c)
Fe-OMS-2(0.09); (d) Co-OMS-2(0.02); and (e) Cu-OMS-2(0.04). 93
4.8
Schematic incorporation of metals in M-OMS-2 materials.
4.9
XRD pattern of (a) cryptomelane and (b) Ti-, (c) Cu-, (d) Co- and
93
(e) Fe-OMS-2 was prepared by oxidation of its metal ions source
by potassium permanganate in acidic condition without the
addition of Mn2+ solution.
97
4.10
Morphology of OMS-2 and M-OMS-2 samples.
101
4.11
Schematic synthesis of H-OMS-2 and H-M-OMS-2.
102
4.12
XRD pattern of (a) OMS-2 and (b) H-OMS-2.
103
4.13
Morphology of H-OMS-2 and H-M-OMS-2 samples.
105
4.14
X-ray diffractograms of (a) cryptomelane (JCPDS 29, 102), (b)
OMS-2, (c) Ti-OMS-2 (0.18), (d) Ti-OMS-2 (0.43), (e) Ti-OMS-2
(0.67), (f) TiO2-OMS-2 (imp) and (g) Ti-OMS-2 (mix).
4.15
IR spectra at lower wavelength region of (a) OMS-2, (b)
Ti-OMS-2 (0.18), (c) Ti-OMS-2 (0.67).
4.16
111
Photoluminescence spectra of OMS-2, Ti-OMS-2 (0.43) and
TiO2-OMS-2 (mix). The excitation wavelength is 430 nm.
4.18
110
IR spectra at higher wavelength region of (a) OMS-2, (b)
Ti-OMS-2 (0.18), (c) Ti-OMS-2 (0.67).
4.17
108
113
FTIR spectra of (a) Ti-OMS-2 (0.67) and (b) OMS-2 after
evacuation under vacuum at 400 oC for 4 h followed by pyridine
adsorption at room temperature and evacuation at 150 oC for an
hour.
4.19
114
Morphology of (a) Ti-OMS-2 (0.18), (b) Ti-OMS-2 (0.18) and
(c) TiO2-OMS-2 (imp).
115
xvii
4.20
N2 adsorption isotherm for OMS-2 at 77 K.
4.21
N2 adsorption isotherm for (a) Ti-OMS-2(0.43) and (b)
Ti-OMS-2(0.67) at 77 K.
4.22
118
TGA profile (a) in original and (b) differential forms of OMS-2,
Ti-OMS-2 (0.18) and TiO2-OMS-2 (imp).
4.23
116
120
Detailed XPS spectra for the Mn 2p transition for (a) OMS-2, (b)
Ti-OMS-2(0.18), (c) Ti-OMS-2(0.67) and (d) TiO2-OMS-2(imp). 123
4.24
Bond strength on bridging oxygen atom.
4.25
Detailed XPS spectra for the Ti 2p transition for (a) Ti-OMS-2
(0.18), (b) Ti-OMS-2(0.67) and (c) TiO2-OMS-2(imp).
4.26
126
FTIR spectra of modified OTS samples (a) OTS/OMS-2 and (b)
OTS/Ti-OMS-2.
4.27
125
128
Percentage of adsorbed water on the sample (a) OMS-2, (b)
Ti-OMS-2(0.67), (c) OTS/Ti-OMS-2(0.67) and (d) OTS/OMS-2. 128
4.28
Proposed polymeric octadecylsiloxane on the surface of OMS-2
and Ti-OMS-2 samples.
4.29
129
XRD pattern of Ti-OMS-2(0.04) and sulphated Ti-OMS-2 (0.04).
# = TiOSO4.H2O,* = MnSO4 7H2O ¤ = MnSO4.
130
4.30
FTIR spectra of Ti-OMS-2 and sulphated Ti-OMS-2.
131
4.31
The bridging of bidentated structure of sulphated Ti-OMS-2.
132
4.32
Thermograms (TGA) of samples.
133
4.33
First derivative curves (DTGA) of samples.
133
4.34
FESEM micrograph of SW150-Ti-OMS-2(0.67) sample in
different magnitude.
134
5.1
The schematic reaction of benzyl alcohol to benzaldehyde.
136
5.2
Overall alcohol oxidation mechanism [24].
139
5.3
Resonance model of Mn-O-Mn bond structure: Resonance
structure in crystalline OMS-2 (Structure A); and non-resonance
structure in amorphous materials (Structure B).
140
xviii
5.4
Schematic reaction of cyclohexane.
5.5
The conversion and product selectivity of oxidation of
141
cyclohexane with tert-butyl hydroperoxide (TBHP) using OMS-2,
M-OMS-2 and H-M-OMS-2. All reactions were carried out at
60 ºC for 24 h with cyclohexane (26 mmol), 70% aqueous TBHP
(10 mmol), and catalyst (50 mg) under reflux condition.
5.6
142
The relationship of ionic radii of metals substituted OMS-2 to
conversion of cyclohexane.
144
5.7
Yield of products vs time on Ti-OMS-2.
146
5.8
Homolytic pathway to form radical from TBHP over catalyst.
148
5.9
Formation of cyclohexyl hydroperoxide.
148
5.10
The heterolytic pathway of the formation of cyclohexanone from
cyclohexyl hydroperoxide.
5.11
The homolytic pathway of the formation of cyclohexanol from
cyclohexyl hydroperoxide.
5.12
148
149
The heterolytic pathway of the formation of cyclohexanol and
cyclohexanone from 1,4-dicyclohexyltetraoxidane.
149
5.13
Reaction condition of cyclohexene and its products.
150
5.14
The conversion and product selectivity of oxidation of
cyclohexene with tert-butyl hydroperoxide (TBHP) using TiO2,
OMS-2, Ti-OMS-2(0.18), and Ti-OMS-2(0.67). {All reactions
were carried out at 70 ºC for 2 h with cyclohexene (5 mmol), 70%
aqueous TBHP (10 mmol), acetonitrile (15 ml) and catalyst (50
mg). The conversion and the amount of product obtained in
blank experimental have been subtracted}.
5.15
Oxidation of styrene and its product on catalysts using TBHP as
oxidant.
5.16
151
The conversion and product selectivity of oxidation styrene with
tert-butyl hydroperoxide (TBHP) using TiO2, TiO2-OMS-2,
Ti-OMS-2, OMS-2 and TS-1. All reactions were carried out at
153
xix
70 oC with styrene (5 mmol), 70% aqueous TBHP (10 mmol),
acetonitrile (15 ml) and catalyst (50 mg) with vigorous stirring.
5.17
154
Consecutive oxidation and acid reaction to form of 1,2 octane diol
from 1-octene on sulphated Ti-OMS-2 catalyst.
159
5.18
Yield of epoxyoctane and 1,2 octane diol after 24 h reaction.
159
6.1
Assignments of modified OMS-2 in oxidation of cyclohexane and
consecutive reaction of 1-octene to 1,2 octanediol consecutive
reaction of 1-octene to 1,2 octanediol
6.2
167
The role of the location of Ti sites in Ti-OMS-2 in oxidation of
cyclohexane, cyclohexene and styrene.
169
xx
LIST OF SYMBOLS/ABBREVIATIONS
%
-
percent
~
-
approximately
μ
-
micron (10-6)
2
-
Bragg angle
Å
-
angstrom (10-10)
a.u.
-
arbitrary unit
BET
-
Brunnauer, Emmett and Teller
c.a.
-
about (Latin:circa)
cm-1
-
per centimeter
2+
Co
-
Cobalt ion
Co-OMS-2
-
Cobalt substituted OMS-2
Cu K
-
X-ray diffraction from copper K energy levels
Cu2+
-
Copper ion
Cu-OMS-2
-
Copper substituted OMS-2
d
-
distance
DTG
-
Differential thermogravimetry
e.g.
-
example (Latin: exempli gratia)
EDAX
-
Energy dispersive analysis by X-ray
equilibrium pressure and vapour pressure Po of the
adsorbate at the temperature where the isotherm is
measured
et al.
-
and others (Latin: et alia)
eV
-
electrovolt
Fe
-
Iron ion
Fe-OMS-2
-
Iron substituted OMS-2
FESEM
-
Field Emission Scanning Electron Microscope
FID
-
Flame ionisation detector
FTIR
-
Fourier transform infrared
3+
xxi
g
-
grams
h
-
hour
H2 O2
-
Hydrogen peroxide
HF
-
Hydrofluoric acid
i.e.
-
that is (Latin : id est)
IUPAC
-
International Union of Pure and Applied Chemistry
K
-
degree Kelvin
KBr
-
Potassium bromide
M
-
Molar
mg
-
meter square per gram
mA
-
milliampere
min
-
minute
mL
-
millilitre
mol
-
mole
M-OMS-2
-
Metal substituted OMS-2
N2
-
Molecular nitrogen
nm
-
nanometer (10-9)
o
-
degree celcius
OL-1
-
OL-1 is manganese oxide Octahedral layered with
interlayer spacing of ~7 Å.
OMS-1
-
Manganese oxide octahedral molecular sieve with 3 x 3
tunnel structure.
OMS-2
-
Manganese oxide octahedral molecular sieve with 2 x 2
tunnel structure.
OMS-5
-
Manganese oxide octahedral molecular sieve with 2 x 4
tunnel structure.
OMS-6
-
Manganese oxide octahedral molecular sieve with 2 x 3
tunnel structure.
OMS-7
-
Manganese oxide octahedral molecular sieve with 1 x 1
tunnel structure.
OTS
-
Octadecyltrichlorosilane
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
SO42-/Ti-OMS-2
-
Sulphated Ti-OMS-2
ST150-Ti-OMS-2
-
Sulphated Ti-OMS-2 with 150 L concentrated H2SO4
using toluene as solvent
2 -1
C
xxii
ST200-Ti-OMS-2
-
Sulphated Ti-OMS-2 with 200 L concentrated H2SO4
using toluene as solvent
SW150-Ti-OMS-2
-
Sulphated Ti-OMS-2 with 150 L concentrated H2SO4
using water as solvent
SW200-Ti-OMS-2
-
Sulphated Ti-OMS-2 with 200 L concentrated H2SO4
using toluene as solvent
t
-
crystallite size
TBHP
-
tert-butyl hydroperoxide
TGA
-
Thermogravimetry analysis
Ti
-
Titanium ion
TiO2
-
Titanium dioxide
3+
TiO2-OMS-2 (imp) -
Impregnation of TiO2 on OMS-2 surface
TiO2-OMS-2 (mix) -
Physical mixture of rutile TiO2 and OMS-2
Ti-OMS-2
-
Titanium substituted OMS-2
TS-1
-
Titanium Silicate-1
wt %
-
weight percentage
-
wavelength
xxiii
LIST OF PUBLICATIONS AND PRESENTATIONS
1. H. Nur, F. Hayati, H. Hamdan, "On the location of different titanium sites in TiOMS-2 and their catalytic role in oxidation of styrene", Catalysis
Communications, 8 (2007) 2007-2011.
2. F. Hayati, H. Nur, H. Hamdan, "Titanium Doped Octahedral Manganese Oxide
Hybrid Catalyst in the Oxidation of Cyclohexene", Buletin Kimia, 21 (2005) 4954.
3. F. Hayati, H. Hamdan, H. Nur, "Synergetic effect of titanium and OMS-2 as TiOMS-2 hybrid catalyst in oxidation of cyclohexene", Book abstract of Annual
Fundamental Science Seminar 2005, 4-1 July 2005, Johor Bahru, Malaysia. p. 67.
4. F. Hayati, H. Nur and H. Hamdan, "Synthesis and characterization of octahedral
molecular sieves (OMS-2)", Book of abstract of Annual Fundamental Science
Seminar 2004, 14-15 June 2004, Johor Bahru, Malaysia. p. 73.