MESOPOROUS MCM-48 SYNTHESIZED FROM RICE HUSK ASH SILICA:

PHYSICOCHEMICAL PROPERTIES AND ITS CATALYTIC ACTIVITY IN

ACYLATION REACTION

LAU CHIN GUAN

UNIVERSITI TEKNOLOGI MALAYSIA

MESOPOROUS MCM-48 SYNTHESIZED FROM RICE HUSK ASH SILICA:

PHYSICOCHEMICAL PROPERTIES AND ITS CATALYTIC ACTIVITY IN

ACYLATION REACTION

LAU CHIN GUAN

A thesis submitted in fulfilment of the

requirements for the award of the degree of

Master of Science (Chemistry)

Faculty of Science

Universiti Teknologi Malaysia

MARCH 2005

iii

For the Lord Almighty,

my beloved familyand

specially for Yang Eik Hien

iv

ACKNOWLEDGEMENTS

Halleluyah! All praise, glory and thanks to almighty God for His amazing

grace that led me throughout the whole process of completing this research.

Heartfelt thanks to my project supervisor, Assoc. Prof. Dr. Salasiah Endud,

who introduced me to the field of mesomorphous materials. Her patience,

understanding, supervision and thoughtful guidance throughout this study is greatly

appreciated. I am particularly grateful to MOSTI for financial support in this study

through IRPA funding 09-02-06-0057-SR0005/09-04.

I wish to express my special appreciation to Dr. Hadi Nur, the lecturer of

Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia,

for giving me worthy advices, valuable suggestions and constructive discussions

particularly in the vision of scientific ethics for conducting a research. I would also

like to thank Lim Kheng Wei for helping me to carry out the 27Al MAS NMR

measurements. My appreciation is also extended to Norizah bt. Abdul Rahman who

help me recorded field emission SEM images in University of Yamagata, Yonezawa,

Japan. Not forgetting all of the laboratory staffs of Faculty Science and the member

of Zeolite and Porous Materials Group (ZPMG), who have in many ways contributed

and gave me moral support to the success of my study.

I am grateful for my family’s ceaseless love and support whenever I need.

My heartfelt thanks and gratitude to the church members of Inter-Vasity Christian

Centre (IVCC) for their endless prayer and encouragement throughout the whole

duration of this research.

The holistic life during this research is unable to be achieved without the

companion of everyone mentioned. Kudos to all of you!!

v

PREFACE

This thesis is the result of my work carried out in the Department of Chemistry,

Universiti Teknologi Malaysia between Jun 2002 to September 2004 under supervision

of Assoc. Prof. Dr. Salasiah Endud. Part of my work described in this thesis has been

reported in the following publications:

1. Lau, C.G. and Endud, S. (2002). “Sintesis Bahan Mesoliang MCM-48

Menggunakan Campuran Templat Surfaktan Kationik dan Neutral.” Proceedings

of the Fifth UKM-ITB Joint Seminar on Chemistry. Bandar Hilir, Melaka. 16-17

July. 425-432.

2. Lim, K.W., Lau, C.G. and Endud, S. (2002). “High Surface Area Catalysts for

Alkylation and Oxidation Reactions”. Poster presentation at the 15th Simposium

Kimia Analisis Kebangsaan (SKAM-15). Universiti Sains Malaysia, Minden,

Pulau Pinang. 10-12 September. P 90.

3. Lau, C.G. and Endud, S. (2003). “Optimization of Synthesis of Mesoporous

Materials from Carbonaceous Rice Husk Ash”. Report for Post-Graduate Study

1st Assessment. Pusat Pengajian Siswazah, Universiti Teknologi Malaysia.

4. Lau, C.G. and Endud, S. (2003). “Synthesis of Mesoporous Materials from

Carbonaceous Rice Husk Ash (RHA) and Its Application As Catalyst In Friedel-

Crafts Reaction” Annual Meeting of Zeolite and Porous Materials Group. A

Farmosa, Melaka.

vi

5. Lau, C.G. and Endud, S. (2003). “Hydrothermal Stability of MCM-48

Mesoporous Molecular Sieves: Effect of Aluminium Content”. Proceedings of

Annual Fundamental Science Studies. Johor Bahru, Johor. 20-21 May. 115-120.

6. Lau, C.G. and Endud, S. (2003). “Phase Transformation of Mesoporous

Molecular Sieves: Effect of Sodium Hydroxide.” Oral presentation at the 16th

Simposium Kimia Analisis Kebangsaan (SKAM-16), Universiti Malaysia

Sarawak, Kuching, Sarawak. 9-11 September 2003. 2C-01.

7. Nur, H., Lau, C.G., Endud, S. and Hamdan, H. (2004). “Quantitative

Measurement of A Mixture of Mesophases Cubic MCM-48 and Hexagonal

MCM-41 by 13C CP/MAS NMR” Materials Letters. 58. 1971-1974.

8. Lau, C.G., Nur, H. and Endud, S. (2004). “Preparation of MCM-48 with A

Bimodal Pore Size Structure by Post-Synthesis Alumination”. Oral presentation

at the Regional Symposium on Membrane Science & Technology 2004. Johor

Bahru, Johor. 21-25 April.

9. Lau, C.G., Nur, H. and Endud, S. (2004). “Highly Effective Cubic Aluminated

Mesoporous Catalyst in Friedel-Crafts Acylation”. Proceedings of 2004 Annual

Fundamental Science Seminar 2004. Skudai, Johor. 14-15 June.

10. Lau, C. G., Nur, H. and Endud S. (2005). “Bimodal Pore Size Mesoporous

MCM-48 Materials Prepared by Post-Synthesis Alumination”. J. Phys. Sci.

(accepted ).

vii

ABSTRACT

The cubic structural mesoporous molecular sieves Si-MCM-48 has been successfully controlled by optimizing the gel compositions via a mixed surfactant templating route using cationic cetyltrimethylammonium bromide (CTABr) and neutral Triton X-100 (TX-100) surfactants. Rice husk ash, an agricultural waste obtained from an open burning site with high silica content (93 % SiO2) has been utilized as active silica reagent in the synthesis process. The Si-MCM-48 mesoporous materials were structurally characterized by X-Ray Powder Diffraction (XRD), and Fourier Transform Infrared Spectroscopy (FTIR). The results show that the crystallinity and phases of the products depend on the compositions of Na2O, surfactants, H2O and pH values. Moreover, 13C CP/MAS NMR technique had been developed to quantify a mixture of cubic MCM-48 and hexagonal MCM-41 mesophases by means of interpretation of their surfactant organization, which cannot be determined by XRD technique. In order to generate active sites for catalytic applications, alumino-mesoporous materials Al-MCM-48 were prepared by post-synthesis alumination of mesoporous Si-MCM-48 and post-synthesis alumination of Si-MCM-48 mesophase using sodium aluminate as the aluminium reagent. The aluminated MCM-48 materials were characterized using XRD, 27Al MAS NMR, FTIR and nitrogen adsorption-desorption measurements. The results reveal that unimodal Al-MCM-48, which possesses narrow pore size distribution around 26Å, had been synthesized from post-synthesis alumination of mesoporous Si-MCM-48. Whereas, bimodal Al-MCM-48, which possesses dual narrow pore size distributions around 26 Å and 38 Å had been generated by post-synthesis alumination of uncalcined Si-MCM-48 mesophase. 27Al MAS NMR results depict that aluminium had been tetrahedrally incorporated into the framework structure of MCM-48. The nature and the concentration of acid sites of Al-MCM-48 materials have been monitored by IR spectroscopy using pyridine as the probe molecule and temperature-programmed desorption of ammonia (TPDA). Acidity studies on the samples demonstrated that the acidity strength of samples prepared via post-synthesis alumination of mesoporous Si-MCM-48 is greater than samples prepared via post-synthesis alumination of Si-MCM-48 mesophase. Aluminated MCM-48 materials have been employed in the acylation of bulky aromatic compound, 2-methoxynaphthalene with acetic chloride to produce 2-acetyl-6-methoxynaphthalene, which is intermediate for preparing naproxen, a non-steroidal anti inflammation drug. Catalytic activities have been investigated in solvents with different polarity and the results illustrate that the conversion and selectivities of products rely on the polarity of solvent. The conversion of the 2-methoxynaphthalene can be as high as 42 % with 86 % selectivities towards the desired 2-acetyl-6-methoxynaphthalene in polar solvent, nitrobenzene. Whereas, the conversion of the 2-methoxynaphthalene is 30 % with 56 % selectivity of 2-acetyl-6-methoxynaphthalene in non-polar solvent, cyclohexane.

viii

ABSTRAK

Penapis molekul mesoliang Si-MCM-48 yang berbentuk kiub telah berjaya disintesis dengan mengoptimumkan komposisi gel melalui kaedah campuran surfaktan kationik setiltrimetilammonium bromida (CTABr) dan surfaktan neutral Triton X-100 (TX-100). Abu sekam padi yang mempunyai kandungan silika yang tinggi (93 % SiO2), di mana ia diambil daripada kawasan pembakaran terbuka telah digunakan sebagai sumber silika yang aktif dalam proses sintesis ini. Struktur penapis molekul mesoliang Si-MCM-48 ini dicirikan dengan kaedah pembelauan sinar-X (XRD) dan spektroskopi inframerah transformasi Fourier (FTIR). Keputusan menunjukkan darjah kehabluran dan ketulenan fasa bahan mesoliang adalah bergantung kepada komposisi Na2O,surfaktan, H2O dan nilai pH. Di samping itu, teknik 13C CP/PSA RMN telah digunakan untuk mengkaji ketulenan fasa campuran MCM-48 yang berfasa kiub dan MCM-41 yang berfasa heksagon secara kuantitatif, di mana ia tidak dapat dilakukan dengan menggunakan kaedah XRD. Aluminium MCM-48 (Al-MCM-48) telah disintesis dengan menggunakan dua kaedah pasca-sintesis untuk menghasilkan tapak aktif pemangkinan, iaitu, penyelitan aluminium ke dalam bingkaian Si-MCM-48 dan penyelitan aluminium ke dalam fasa meso Si-MCM-48 dengan menggunakan natrium aluminat sebagai sumber aluminium. Sampel Al-MCM-48 dicirikan dengan kaedah XRD, 27Al PSA RMN, FTIR dan penjerapan dan nyahjerapan nitrogen. Analisis penjerapan nitrogen menunjukkan liang Al-MCM-48 yang bersebar secara seragam dengan purata liang disekitar taburan 26 Å telah dihasilkan dengan menggunakan kaedah penyelitan aluminium ke dalam bingkaian bahan mesoliang Si-MCM-48. Di samping itu, Al-MCM-48 yang memiliki taburan dua jenis mesoliang yang tertabur di antara 26 Å dan 38 Å telah dihasilkan melalui kaedah penyelitan aluminium ke dalam fasa meso Si-MCM-48 tanpa kalsin. Keputusan 27Al PSA RMN menunjukkan aluminium bingkaian berkordinatan tetrahedral telah dihasilkan melalui kedua-dua kaedah tersebut. Jenis dan kepekatan tapak asid yang terdapat pada permukaan Al-MCM-48 telah ditentukan dengan menggunakan kaedah spektroskopi inframerah menggunakan piridina sebagai molekul prob dan kaedah nyahjerapan ammonia pada suhu terkawal (TPDA). Hasil kajian keasidan menunjukkan sampel yang disediakan melalui penyelitan aluminium ke dalam bingkaian bahan mesoliang Si-MCM-48 adalah lebih kuat daripada sampel yang disediakan melalui penyelitan aluminium ke dalam fasa meso Si-MCM-48 tanpa kalsin. Potensi bahan Al-MCM-48 sebagai mangkin Friedel-Crafts telah diuji dengan menggunakan tindak balas pengasilan sebatian 2-metoksinaftalena dengan asetil klorida untuk menghasilkan 2-asetil-6-metoksinaftalena, bahantara untuk menyediakan naproxen, ubat anti-keradangan yang non-steroid. Kajian aktiviti pemangkinan dengan menggunakan pelarut yang berlainan kepolaran menunjukkan peratus pertukaran dan kepilihan produk adalah bergantung kepada kepolaran pelarut. Peratus pertukaran 2-metoksinaftalena boleh mencapai setinggi 42 % dengan 86 % kepilihan kepada 2-asetil-6-metoksinaftalena di dalam pelarut polar (nitrobenzena). Di samping itu, peratus pertukaran 2-metoksinaftalena hanya sebanyak 30 % dengan 56 % kepilihan kepada 2-asetil-6-metoksinaftalena di dalam pelarut yang tidak polar (sikloheksana).

ix

TABLE OF CONTENTS

CHAPTER TITLE PAGE

TITLE

STATEMENT

DEDICATION

ACKNOWLEDGEMENTS

PREFACE

ABSTRACT

ABSTRAK

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

LIST OF SYMBOLS

LIST OF APPENDICES

i

ii

iii

iv

v

vii

viii

ix

xiv

xvi

xxiii

xxv

1 INTRODUCTION

1.1 Green Chemistry for Sustainable Development

1.2 Heterogeneous Catalysts

1.3 Research Background and Problem Statement

1.4 Research Objectives

1.5 Scope of the Study

1.6 Outline of the Thesis

1

2

4

6

6

7

x

2 EXPERIMENTAL

2.1 Chemical Analysis of Rice Husk Ash (RHA)

2.1.1 Determination of LOI (Loss of Ignition)

2.1.2 Determination of Silica

2.2 Synthesis of Purely Siliceous Si-MCM-48

Materials Via A Mixed Cationic-Neutral

Templating Route

2.3 Removal of Organic Templates

2.4 Synthesis of Aluminated Cubic Mesoporous

Materials (Al-MCM-48)

2.5 Preparation of Protonated Al-MCM-48 (H-Al-

MCM-48)

2.6 Charaterization of MCM-48 Molecular Sieves

2.6.1 Powder X-Ray Diffraction (XRD)

2.6.2 Fourier Transform Infrared Spectroscopy

(FTIR)

2.6.3 Magic Angle Spinning Nuclear Magnetic

Resonance (MAS NMR)

2.6.4 Nitrogen Adsorption Measurements

2.6.5 Field Emission Scanning Electron

Microscopy (FESEM)

2.6.6 Acidity Measurement

2.7 Catalytic Testing

2.7.1 Activation of H-Al-MCM-48

2.7.2 Acylation of 2-Methoxynapthalene with

Acetyl Chloride over H-Al-MCM-48

9

9

9

10

11

12

14

15

15

16

16

17

18

18

19

19

21

3 OPTIMIZATION OF SYNTHESIS AND

CHARACTERIZATION OF PURELY SILICEOUS

MESOPOROUS MOLECULAR SIEVES MCM-48

3.1 Introduction 23

xi

3.2 Proposed Formation Mechanisms and the

Evolution of Synthesis Routes for the M41S

Mesoporous Materials

3.3 Synthesis of MCM-48 Materials

3.4 Results and Discussion

3.4.1 Characterization of Rice Husk Ash (RHA)

3.4.2 Synthesis of Purely Siliceous Mesoporous

Materials

3.4.2.1 Effect of pH Value

3.4.2.2 Effect of Sodium Oxide/Silica

(Na2O/SiO2) Ratio

3.4.2.3 Effect of Surfactant/Silica

(Sur/SiO2) Ratio

3.4.2.4 Effect of Water/Silica (H2O/SiO2)

Ratio

3.5 Conclusion

26

29

32

32

33

35

40

44

46

49

4 QUANTITATIVE MEASUREMENT OF PHASE

COMPOSITION OF CUBIC MCM-48 AND

HEXAGONAL MCM-41 PHASE MIXTURES BY

USING 13C CP/MAS NMR

4.1 Introduction

4.2 Results and Discussion

4.3 Conclusion

50

52

59

5 TAILORING THE ALUMINOSILICATE

Al-MCM-48 MESOPOROUS MOLECULAR SIEVES

AS CATALYSTS FOR FRIEDEL-CRAFTS

REACTION

5.1 Introduction 60

xii

5.2 Post-Synthesis Route to Mesoporous Al-MCM-48

Materials

5.3 Results and discussion

5.3.1 Post-Synthesis Alumination of Mesoporous

Si-MCM-48

5.3.2 Post-Synthesis Alumination of Si-MCM-48

Mesophase

5.3.3 Proposed Mechanism

5.4 Conclusion

61

62

62

73

84

87

6 CATALYTIC ACTIVITY OF ALUMINATED

MCM-48 MOLECULAR SIEVES IN THE FRIEDEL-

CRAFTS ACYLATION OF

2-METHOXYNAPHTHALENE WITH ACETYL

CHLORIDE

6.1 Introduction

6.2 Generation of Active Sites in Al-MCM-48

6.3 Characterizationof Acidity

6.4 Friedel-Crafts Acylation

6.5 Results and Discussion

6.5.1 Characterization of Acidity of Al-MCM-48

6.5.1.1 Temperature-Programmed

Desorption of Ammonia (NH3-

TPD)

6.5.1.2 Infrared Spectroscopy (IR) of

Adsorbed Pyridine

6.5.2 Acylation of 2-Methoxynapthalene with

Acetyl Chloride

6.5.2.1 The Effect of Various Catalysts

6.5.2.2 The Effect of Solvent

6.6 Conclusion

88

89

93

94

97

97

97

100

109

111

114

120

xiii

7 GENERAL CONCLUSION AND

RECOMMENDATIONS

7.1 Main Results 121

7.2 Recommendations 124

REFERENCES 125

APPENDICES 141

xiv

LIST OF TABLES

TABLE NO.

2.1

2.2

2.3

3.1

5.1

5.2

TITLE

Summary of synthesis conditions for Si-MCM-48 materials.

Sample codes for Al-MCM-48 with different concentration

of sodium aluminate prepared by post-synthesis alumination

of mesoporous Si-MCM-48.

Sample codes for Al-MCM-48 with different Si/Al ratio

prepared by post synthesis alumination of Si-MCM-48

mesophase.

Surfactant packing parameter g, expected structure and

examples for such structures.

Unit cell parameters of Al-MCM-48 prepared from the

purely siliceous Si-MCM-48 with different concentrations of

NaAlO2 aqueous solution. The unit cell parameter has been

calculated from the interplanar spacing using the formula

ao=d211√6.

Sorption properties of the parent Si-MCM-48 and the

aluminated samples prepared via post-synthesis alumination

of mesoporous Si-MCM-48.

PAGE

12

13

14

31

66

73

xv

5.3

5.4

6.1

6.2

6.3

6.4

Unit cell parameters of Si-MCM-48 and Al-MCM-48

prepared from post-synthesis alumination. The unit cell

parameter has been calculated from the interplanar spacing

using the formula ao=d211√6.

Sorption properties of Si-MCM-48 and Al-MCM-48.

Total acid amount of H-Al-MCM-48 materials determined by

NH3-TPD.

Number of Brönsted and Lewis acid sites in the samples.

GC Data for the Acylation Products.

Catalytic Activities of Various Catalysts for the Acylation of

2-Methoxynaphthalene with Acetyl Chloride.

75

82

100

110

111

112

xvi

LIST OF FIGURES

FIGURE NO.

1.1

1.2

2.1

2.2

3.1

3.2

3.3

3.4

3.5

TITLE

Development of publications on ordered mesoporous

materials since 1990.

Flowchart of the research design.

Experimental setup for acidity study .

GC-FID and GC-MS oven-programme setup.

Schematic structural illustrations of M41S family (a)

hexagonal MCM-41; (b) cubic MCM-48; (c) lamellar

MCM-50.

Schematic of possible mechanistic pathways for the

formation of MCM-41: (1) Liquid crystal phase initiated

and (2) silicate anion initiated.

Schematic diagram of the transformation mechanism from

lamellar to hexagonal mesophase.

Schematic showing of interfacial interactions for surfactant

micelles in cooperatively assembly.

Illustration of the regions of generic surfactant.

PAGE

3

8

20

21

24

26

27

28

30

xvii

3.6

3.7

3.8

3.9

3.10

3.11

4.1

4.2

XRD diffractogram of RHA obtained from an open burning

site.

FTIR spectrum of RHA obtained from open burning site.

XRD diffractograms of (a) as-synthesized mesoporous

materials; (b) calcined mesoporous materials with various

pH value.

XRD diffractograms of (a) as-synthesized mesoporous

materials; (b) calcined mesoporous materials with various

Na2O/SiO2 ratios.

XRD diffractograms of (a) as-synthesized mesoporous

materials; (b) calcined mesoporous materials with various

Sur/SiO2 ratios.

XRD diffractograms of (a) as-synthesized mesoporous

materials; (b) calcined mesoporous materials with various

H2O/SiO2 ratios.

X-ray diffraction (XRD) patterns of mesophases MCM-48

and/or MCM-41 prepared by difference of the Na2O/SiO2

ratio; (a) 0.20, (b) 0.25, (c) 0.30, (d) 0.35 and (e) 0.40.

XRD pattern (f) was obtained by mixing samples (a) and

(e) with the composition of 50:50.

13C CP/MAS NMR spectra of mesophases MCM-48 and/or

MCM-41 prepared with various Na2O/SiO2 ratios; (a) 0.20,

(b) 0.25, (c) 0.30, (d) 0.35 and (e) 0.40. A contact time of 1

ms was applied.

34

34

37

41

45

47

53

55

xviii

4.3

4.4

4.5

5.1

5.2

5.3

5.4

5.5

Integrated intensity ratio of the C5–C14 and C1 peaks

(normalized to percentage of mesophases MCM-48 and

MCM-41), calculated from Figure 4.2, of MCM-48 and/or

MCM-41 prepared with various Na2O/SiO2 ratios; (a) 0.20,

(b) 0.25, (c) 0.30, (d) 0.35 and (e) 0.40.

X-Ray diffraction (XRD) patterns of mesoporous (a)

MCM-48 and (b) MCM-41 after reinsertion of CTABr.

13C CP/MAS NMR spectra of mesoporous (a) MCM-48

and (b) MCM-41 after reinsertion of CTABr. A contact

time of 1 ms was applied.

XRD patterns of the parent Si-MCM-48 and its aluminated

samples through secondary synthesis with different

concentrations of NaAlO2.

Mechanism of post-synthesis alumination of mesoporous

MCM-41.

FTIR spectra of the parent and samples prepared via post-

synthesis of mesoporous Si-MCM-48 with different

concentrations of NaAlO2; (a) purely siliceous Si-MCM-48

(MP-5), (b) 0.10 M, (c) 0.25 M, and (d) 0.50 M.

27Al MAS NMR spectra of Al-MCM-48 prepared via post-

synthesis alumination of mesoporous Si-MCM-48 with

different concentrations of NaAlO2.

N2 adsorption-desorption isotherms and its BJH pore size

distribution curve (inset) of the parent Si-MCM-48 and its

aluminated samples through post-synthesis alumination of

mesoporous Si-MCM-48 with different concentrations of

NaAlO2; (a) purely siliceous Si-MCM-48 (MP-5),

56

57

58

63

65

67

68

70

xix

5.6

5.7

5.8

5.9

5.10

5.11

5.12

5.13

5.14

5.15

(b) 0.10M, (c) 0.25 M, and (d) 0.50 M.

The αs plots of (a) Si-MCM-48, (b) 010Al-MCM-48, (c)

025Al-MCM-48, and (d) 050Al-MCM-48.

XRD patterns of the (a) as-synthesized and (b) calcined Al-

MCM-48 via post-synthesis alumination.

FTIR spectra of aluminosilicates Al-MCM-48 samples

prepared by post-synthesis alumination with various Si/Al

ratios; (a) 20, (b) 30, (c) 50, and (d) 100.

27Al MAS NMR spectra of the calcined aluminosilicate Al-

MCM-48 samples prepared by post-synthesis alumination

with various Si/Al ratios; (a) 20, (b) 30, (c) 50, and (d) 100.

N2 adsorption-desorption isotherms and their corresponding

pore size distribution curve (inset) of aluminosilicate Al-

MCM-48 samples prepared by post-synthesis alumination

with various Si/Al ratios; (a) 20, (b) 30, (c) 50, and (d) 100.

The αs plots of aluminosilicate Al-MCM-48 samples

prepared through post-synthesis alumination with different

Si/Al ratios; (a) 20, (b) 30, (c) 50, and (d) 100.

FESEM micrograph of Si-MCM-48.

FESEM micrograph of Al-MCM-48-50.

Proposed mechanism of post-synthesis alumination of

Si-MCM-48 mesophase.

Schematic illustration of formation mechanism of

secondary mesopores.

72

74

77

78

79

81

83

83

85

86

xx

6.1

6.2

6.3

6.4

6.5

6.6

6.7

6.8

6.9

6.10

(a) Framework of Si-MCM-48, and (b) Framework of

Al-MCM-48.

Generation of Brönsted acid sites.

Generation of Lewis acid sites; (a) Lewis acidity due to

framework tricoordinated aluminium, and (b) Lewis acidity

associated with both octahedral and tetrahedral EFAL.

Mechanism of acylation of aromatics in the presence of

aluminium chloride.

The active positions of 2-methoxynaphthalene.

NH3-TPD spectra of samples prepared through post-

synthesis alumination of Si-MCM-48 mesoporous materials

with different concentration of NaAlO2.

NH3-TPD spectra of samples prepared through post-

synthesis alumination of Si-MCM-48 mesophase with

different Si/Al gel ratios.

FTIR spectra in the hydroxyl region of (a) Si-MCM-48, (b)

010AlMCM-48, (c) 025AlMCM-48, and (d) 050AlMCM-

48 recorded at 400 oC under 10-5 mbar pressure.

FTIR spectra in the hydroxyl region of (a) Si-MCM-48, (b)

Al-MCM-48-20, (c) Al-MCM-48-30, (d) Al-MCM-48-50,

and (e) Al-MCM-48-100 recorded at 400 oC under 10-5

mbar pressure.

FTIR spectra in the hydroxyl region after pyridine

desorption at 150 oC; (a) Si-MCM-48, (b) 010Al-MCM-48,

(c) 025Al-MCM-48, and (d) 050Al-MCM-48.

90

91

92

95

97

98

99

102

103

104

xxi

6.11

6.12

6.13

6.14

6.15

6.16

6.17

6.18

FTIR spectra in the hydroxyl region after pyridine

desorption at 150 oC (a) Si-MCM-48, (b) Al-MCM-48-20,

(c) Al-MCM-48-30, (d) Al-MCM-48-50, and

(e) Al-MCM-48-100.

Structures showing interaction of (a) silanols with Lewis

acid sites and (b) Al-OH groups by H-bonding (represented

by arrows).

FTIR spectra of adsorbed pyridine on Si-MCM-48 and

samples prepared through post-synthesis alumination

mesoporous Si-MCM-48 evacuated at 25 oC, 150 oC, 250 oC, and 400 oC. (H, Hydrogen bonded pyridine; B,

Brönsted bound pyridine; L, Lewis bound pyridine).

FTIR spectra of adsorbed pyridine on samples prepared

through post-synthesis alumination Si-MCM-48 mesophase

evacuated at 25 oC, 150 oC, 250 oC, and 400 oC. (H,

Hydrogen bonded pyridine; B, Brönsted bound pyridine; L,

Lewis bound pyridine).

Effect of solvents on conversion of 2-methoxynaphthalene

over Al-MCM-48-20.

Effect of solvents on selectivity of the products from

acylation of 2-methoxynaphthalene over Al-MCM-48-20

catalyst.

Products of acylation of 2-methoxynaphthalene catalysed

by H-Al-MCM-48.

Proposed mechanism of the Acylation of

2-methoxynaphthalene with acetyl chloride over Brönsted

acid sites in Al-MCM-48.

105

106

107

108

116

116

117

118

xxii

6.19 Proposed mechanism of the acylation of

2-methoxynaphthalene with acetyl chloride over Lewis

acid sites in Al-MCM-48.

119

xxiii

LIST OF SYMBOLS

RHA

LOI

L

mLoC

K

g

min

h

MCM

M

Si/Al

Si-MCM-48

Al-MCM-48

XRD

FTIR27Al MAS NMR13C CP/MAS NMR

TPD

FESEM

d

Cu-Kα

λ

kV

mA

2θ

rice husk ash

loss of ignition

litre

millilitre

Celsius

Kelvin

gram

minute

hour

Mobile Composition Material

molar

silicon-to-aluminium ratio

purely siliceous MCM-48

aluminosilicate MCM-48

X-Ray diffraction

Fourier Transform Infrared27Al magic-angle-spinning nuclear-magnetic-resonance13C cross-polarization magic-angle-spinning nuclear-

magnetic-resonance

temperature-programmed desorption

field emission scanning electron microscopy

inter-planar spacing

X-ray diffraction from copper Kα energy levels

wavelength

kilovolt

milliampere

Braggs angle

xxiv

KBr

TMS

s

Hz

CaF2

I.D.

GC

GC-MS

FID

IUPAC

AlO4

SiO4

TEM

LCT

g

BET

Si-OH

EFAL

ao

N2

P/Po

PSD

BJH

αs

Rt

TON

ms

kalium bromide

tetramethylsilane

second

Hertz

calcium fluoride

internal diameter

gas chromatrography

gas chromatrograpy-mass spectrometry

flame ionization detector

International Union of Pure and Applied Chemistry

aluminate, framework aluminium in zeolite

siliceous; framework silicon in zeolite

transmission electron microscopy

liquid crystal templating

surfactant packing parameter

Brunauer, Emmett and Teller

silanol group

extra framework aluminium

unit cell parameter

nitrogen

relative pressure; obtained by forming the ratio of the

equilibrium pressure and the vapor pressure Po of the

adsorbate at the temperature where the isotherm is

measured.

pore size distribution

Barrett, Joyner and Halenda

alfa-S

retention time

turnover number

millisecond

xxv

LIST OF APPENDICES

APPENDIX

A

B

C

D

E

F

TITLE

Calculation of the amount of pyridine adsorbed on

the sample in the acidity study of secondary

aluminated Al-MCM-48 samples.

Quantitative gas chromatography calibration plot

of 2-methoxynaphthalene by using naphthalene as

internal standard.

Calculation of % conversion, % selectivity, and

turnover number (TON).

An example of chromatogram for liquid products

of conversion of 2-metoxynaphthalene in

nitrobenzene.

An example of chromatogram for liquid products

of conversion of 2-metoxynaphthalene in

dichloroethane.

An example of chromatogram for liquid products

of conversion of 2-metoxynaphthalene in

cyclohexane.

PAGE

141

142

143

144

145

146

xxvi

G

H

Mass spectra of (a) 2-acetyl-6-

methoxynaphthalene and (b) 1-acetyl-7-

methoxynaphthalene.

Quantitative calculation of phase composition via

integrated intensity ratio of the C5–C14 and C1

peaks of 13C CP/MAS NMR spectra of

mesophases.

147

148

CHAPTER 1

INTRODUCTION

1.1 Green Chemistry for Sustainable Development

In the 21st century, building a sustainable future has been the greatest

challenge of the global society. The development of science and technology has

become the crucial role in order to fulfilling current need and to preserve a well

living environment for the future generations. Therefore, the public, legislative, and

environmentalists are urging the development of cleaner technologies to serve

mankind. Hence, it has stimulated the exciting opportunities for catalysis and

catalytic processes.

Catalyst is a substance, which accelerates the rate of a chemical reaction

whilst it may be recovered chemically unchanged at the end of the reaction [1]. The

presence of the catalyst is essential for (i) obtaining new structures, (ii) increasing the

productivity, (iii) decreasing the raw materials and energy consumption, (iv)

minimizing the waste production and getting a better environment [2].

Catalysis is a privileged way to a clean and powerful chemistry. Today,

catalysts play a vital role in the chemicals industry, with a total contribution of ca.

20% of the world GNP in the 20th century [3]. In addition, 80% of the industrial

reactions use catalysts. The British agency Frost and Sullivan, which published a

study in 1998 [4] evaluated the catalysts European market to $ 3.7 billions turnover

in 1998. With about 4% growth per year, it should increase to $ 5 billions in 2005.

2

1.2 Heterogeneous Catalysts

Catalysts can be classified into two categories, homogenous and

heterogeneous. Homogenous catalyst is the catalyst, which presents in the same

phase as the reagents. Sulfuric acid has been widely used as homogenous catalyst in

the alkylations or isomerizations of hydrocarbon [5]. Whereas, catalysts are

heterogeneous if they are present in a different phase from the reactants. One of the

prominent heterogeneous catalysts is zeolites which are extensively employed in

petroleum refinery processes [6].

Heterogeneous catalysis is the backbone of the modern chemical industry,

because of the necessity to achieve environmental benign processes in the industry.

In addition, heterogeneous catalysts offer numerous potential advantages over

homogenous catalysts, such as easier working up procedures, easy catalyst separation

from the reaction mixture, reduction of environmental pollutant, avoidance of salt

formation and waste disposals [7].

Since 1960s, zeolites catalysts have conquered the petroleum refining and

petrochemical industries. This is due to the zeolites that have excellent thermal and

chemical stability. Moreover, zeolites provide great acid strength, which are

comparable to homogeneous acid catalysts [7]. The most important of these

processes are hydrocracking of heavy petroleum distillates, octane number

enhancement of light gasoline by isomerization, the isomerization of xylenes (to

produce para-xylene, the precursor chemical for terephthalic acid), and etc [6].

However, the utilization of zeolites in the areas of specialty and fine chemicals

synthesis is still limited, even though their potential is considered to be very high in

this area as well. The small pore opening of zeolites, in the range of ca. 0.2-1 nm, is

a major restriction for it to utilize in organic reactions [6]. The reactants with sizes

exceeding the dimensions of the pore are not able to process via zeolites. Therefore,

numerous attempts have been devoted to increasing the pore size of crystalline

molecular sieves [8].

In 1992, a novel family of ordered silicate mesoporous molecular sieves,

designated as M41S has been discovered by researchers at Mobil R & D Corporation

3

[9]. The most important member among these materials is MCM-41 and MCM-48,

which possesses hexagonal and cubic symmetry, respectively. The uniqueness of

M41S mesoporous materials are the pore size are uniform and tunable in the range

between 1.6-10 nm. Furthermore, these mesoporous materials also possess high

thermal stability and have extremely high surface areas. This innovative discovery

has greatly expanded the area of microporous molecular sieves (zeolites) into the

mesopore range and has created new opportunities beyond catalysis. The ordered

mesoporous materials have been found as promising materials in optics and

electronics, as nano size template, and as adsorbents for heavy metals [10]. The

rapid growing of publications in mesoporous materials since 1990 is shown in Figure

1.1 [10].

Figure 1.1 Development of publications on ordered mesoporous materials since

1990 [10].

4

1.3 Research Background and Problem Statement

Malaysia has been found as one of the major rice production country,

whereby 425,080 hectares (3.21 % of the total land in peninsular Malayisia) of the

land have been used for paddy plantation [11]. Therefore, it generates abundance of

waste namely rice husk, a thin but abrasive skin in nature covering the edible rice

kernel. It has been reported that Malaysia produces a ca. 18 million tons of paddy in

which about one fifth of it is the husk [12]. This means that the annual production of

rice leaves behind about 3.6 million tons of husk as waste product, usually disposed

by combustion. Unfortunately, the 20 % of the rice husk ash (RHA) residues left

after the combustion constitute environmental problems due to severe air and water

pollution problems. However, RHA can be considered as a potential feature of the

rice husk, which the RHA residues can be employed as raw materials in a variety of

applications.

Previous research had shown that the rice husk ash containing 96-99% SiO2

can exist either in amorphous phase or in crystalline phases such as, α-cristobalite

and tridymite [13-14]. In fact, the amorphous silica is the most active silica

precursor in the synthesis of zeolites. Hence, the large amount of silica freely

obtained from this source provides abundant and cheap alternatives of silica for

many industrial uses. From the previous report, MCM-41 has been successfully

synthesized by using the silica extracted from RHA [15]. However, no report has

been found on the synthesis of MCM-48 directly from RHA, since the synthesis of

MCM-48 mesoporous materials seems to be more challenging than the synthesis of

MCM-41. By using rice husk ash as the silica source in the synthesis of MCM-48,

the production costs can be reduced subsequently besides helping to overcome

environmental pollution. Indeed, it should be noticed that RHA is considered

slightly impure silica. The content of silica and all impurities in RHA vary

depending on the variety, climate and geographic location [16]. Therefore, in order

to transform the RHA to valuable mesoporous materials, modification and

optimization of the synthesis condition should be carried out.

The three-dimensional cubic porous system of MCM-48 mesoporous

materials has more advantageous than one-dimensional hexagonal porous system.

5

However, it is particularly difficult to synthesize MCM-48 mesoporous materials,

since cubic MCM-48 mesophase are obtained as an intermediate between the

transformation from a hexagonal or disordered mesophase to a more stable lamellar

mesophase [17]. Hence, instead of pure phase, the mixtures of different phases are

frequently obtained during the synthesis. It is a great challenge to characterize the

mesoporous materials, since the XRD is not capable to distinguish the phases in the

state of mixtures of different ordered mesophases.

Friedel–Crafts acylation of aromatic compounds is one of the prominent

processess in the synthesis of aromatic ketones that has been widely used as an

intermediate to obtain fine, specialty and pharmaceutical chemicals. However, the

majority of these manufacturing processes still rely on homogeneous reagents and

catalysts. Many of these processes are developed simply to maximize product yield,

disregarding the environmental impact of inorganic waste and toxic byproducts

formed during the reaction. Among the Lewis acid catalysts, anhydrous aluminium

chloride was the most widely employed reagent to trigger the Friedel-Crafts reaction

in the liquid phase in the laboratory as well as in the industry. However, the use of

standard Lewis acid catalyst is faced with several problems, such as non-regenerable,

requires further treatment after reaction, produces large amounts of hazardous

corrosive waste, catalyzes undesirable reaction, and also uses more than the

stoichiometric amount. Therefore, the demand for less pollutant and more effective

chemical processes has become the current concern. Zeolites have been found to be

less useful in these chemicals processes due to the limitation of its pore opening for

bulky organic molecules. Conversely, the emergence of mesoporous materials has

breakthrough the restriction of zeolites, since the larger pore size of these materials

allows bulky organic molecules to diffuse through the pores to reach the active sites.

Moreover, utilization of mesoporous materials such as MCM-48 in the production of

fine chemicals is still being studied and developed but is yet to be available

commercially.

6

1.4 Research Objectives

The objectives of this research are:

(1) to establish and optimize a new synthetic mesoporous Si-MCM-48

molecular sieves by using rice husk ash as silica source.

(2) to develop a novel characterization technique for measurement of

mesophases composition.

(3) to synthesis and tailor the unimodal and bimodal of Al-MCM-48 via

post synthesis route.

(4) to characterize the physicochemical properties of Al-MCM-48.

(5) to investigate the catalytic properties of the Al-MCM-48 in the

Friedel-Crafts acylation of 2-methoxynaphthalene with acetyl

chloride.

1.5 Scope of the Study

In this research, syntheses of purely siliceous mesoporous Si-MCM-48

molecular sieves via mixed cationic-neutral templating route have been optimized by

means of varying the initial condition of original gel compositions proposed by Ryoo

et al. [17], such as pH value, Na2O/ SiO2, surfactant/SiO2, and H2O/SiO2.

Cetyltrimethylammonium bromide (CTABr) has been used as cationic surfactant,

whereas Triton X-100 (TX-100) as neutral surfactants. Rice husk ash (RHA) which

were obtained from open burning site will be used as silica source. Moreover, a

novel approach for quantification of mesophase purity by using 13C CP/MAS NMR

has been developed in order to verify the mesophases compositions from hexagonal

MCM-41 to cubic MCM-48.

Modification of MCM-48 is devoted by introducing the aluminium into the

Si-MCM-48 by two post synthesis approaches. Both mesoporous and mesophase of

Si-MCM-48 will be employed as parent materials in post-synthesis alumination.

Acidity of the samples are investigated by using temperature-programmed desorption

(TPD) of ammonia and pyridine adsorption methods.

7

Appropriate techniques are utilized to characterize the physicochemical

properties of the mesoporous materials which include powder X-ray diffraction

(XRD), Fourier Transform Infrared Spectroscopy (FTIR), nitrogen adsorption-

desorption measurement, 27Al magic angle spinning nuclear magnetic resonance

spectroscopy (27Al MAS NMR), and field emission scanning electron microscopy

(FESEM).

Finally, the mesoporous catalysts will be tested as potential catalysts in

laboratory scale. Investigation of its catalytic activity will be conducted using

Friedel-Crafts acylation of bulky aromatic compound, 2-methoxynaphthalene with

acetyl chloride. Solvents with various polarities such as cyclohexane,

dichloroethane, and nitrobenzene will be used in this study. The research design is

schematically illustrated in Figure 1.2.

1.6 Outline of the Thesis

This thesis illustrates the information concerning the synthesis,

characterization and the potential catalytic application of mesoporous MCM-48

molecular sieves. Chapter 1 elucidates the research background and the strategies to

respond the current issue. Chapter 2 describes the experimental methodology.

Whereas, Chapter 3 covers the chemistry and fundamental aspects of mesoporous

MCM-48 molecular sieves. The results of the optimization of synthesis of

mesoporous MCM-48 molecular sieves are also present in this chapter. Chapter 4

explains the novel technique for quantification of mesophases compositions by using13C CP/MAS NMR. Chapter 5 contains the studies in tailoring the unimodal and

bimodal of Al-MCM-48 by using different post-synthesis alumination approaches.

Chapter 6 reveals the discussion of the acidity studies of Al-MCM-48 by using NH3-

TPD and pyridine adsorption. In addition, the catalytic activity of Al-MCM-48

catalysts, which is tested by Friedel-Crafts acylation is presented in this chapter too.

Finally, Chapter 7 summarizes the results obtained with recommendation for future

work.

8

Figure 1.2 Flowchart of the research design.

Characterization of Its Physicochemical Properties

XRD, FTIR, nitrogen adsorption-desorption measurement, 27Al MAS NMR,

FESEM, NH3-TPD, and pyridine adsorption.

Catalytic Testing

Friedel-Crafts acylation

Product

Analysis

Gas Chromatrography (GC)

Gas Chromatrography-Mass Spectrometry (GC-MS)

Modification of Si-MCM-48

Post-Synthesis Alumination of

Mesoporous Si-MCM-48

Post-Synthesis Alumination of

Si-MCM-48 Mesophase

Optimization of Synthesis of Purely

Siliceous Mesoporous Materials

from Rice Husk Ash

Develop A Novel Characterization

Technique for Measurement of

Mesophases Composition by Using 13C CP/ MAS NMR

125

REFERENCES

1. Campbell, I.M. (1988). “Catalysis at Surfaces.” London: Chapman and Hall. 1-

14.

2. Barrault, J., Clacens, J.M., Vanhove, C. and Bancquart, S. (2002). “Catalysis and

Fine Chemistry.” Catal. Today. 75. 177–181.

3. Clark, J.H. (2002). “Solid Acids for Green Chemistry.” Acc. Chem. Res. 35. 791-

797.

4. British agency Frost and SulliInfo Chimie Magazine. (2000). 414. 55.

5. Thomas, J.M. (1994). “Turning Points in Catalysis.” Angew. Chem. Int. Ed. Engl.

33. 913-937.

6. Weitkamp, J. (2000). “Zeolites and Catalysis.” Solid State Ionics. 131. 175–188.

7. Perot, G. and Cuisnet, M. (1990). “Advantages and Disadvantages of Zeolites as

Catalysts in Organic Chemistry.” J. Mol. Catal. 61. 173-196.

8. Naber, J.E., deJong, K.P., Stork, W.H.J., Kuipers, H.P.C.E. and Post, M.F.M.

(1994). “Industrial Applications of Zeolites Catalysis.” Stud. Surf. Sci. Catal. 84.

2197-2219.

126

9. Kresge, C.T., Leonowicz, M.E., Roth, W.J., Vartuli, J.C. and Beck, J.S. (1992).

“Ordered Mesoporous Molecular Sieve Synthesized by A Liquid-Crystal

Template Mechanism”. Nature. 359. 710-712.

10. Schüth, F. (2001). “Ordered Mesoporous Materials – State of the Art and

Prospects.” 13th International Zeolite Conference. July 8-13. Montpellier, France:

PL1.

11. Ahmad, F. (2001). “Sustainable Agriculture System in Malaysia.” Regional

Workshop on Integrated Plant Nutrition System (IPNS), Development in Rural

Poverty Alleviation. September 18-20. Bangkok, Thailand.

12. Ministry of Agricultural. “Malaysian Agricultural Directory and Inde

Kuala Lumpur, Malaysia.

13. Hamdan, H., Muhid, M.N.M., Endud, S., Listorini, E. and Ramli, Z. (1997). “29Si

MAS NMR, XRD and FESEM Studies of the Rice Husk Silica for the Synthesis

of Zeolites.” J. Non-Crystal. Solids. 211. 126-131.

14. Prasetyoko, D. (2001). “Pengoptimuman Sintesis Zeolit Beta Daripada Silika

Sekam Padi: Pencirian Dan Tindak Balas Pemangkinan Friedel-Crafts.”

Universiti Teknologi Malaysia: Thesis Master.

15. Ang, B.K. (2001). “Synthesis and Characterization of MCM-41 and Use As A

Catalyst In Friedel-Crafts Reaction.” Universiti Teknologi Malaysia: Master

Thesis.

16. Sun, L. and Gong, K. (2001). “Silicon-Based Materials from Rice Husks and

Their Applications.” Ind. Eng. Chem. Res. 40. 5861-5877.

127

17. Ryoo, R., Joo, S.H. and Kim, J.M. (1999). “Energetically Favored Formation of

MCM-48 from Cationic-Neutral Surfactant Mixtures.” J. Phys. Chem. B. 103.

7435-7440.

18. Hamdan, H., Endud, S., He, H., Mohd Muhid, M.N. and Klinowski, J. (1996).

“Alumination of the Purely Siliceous Mesoporous Molecular Sieve MCM-41 and

Its Hydrothermal Conversion Into Zeolite Na-A.” J. Chem. Soc. Faraday Trans.

92. 2311-2315.

19. Glusker, J.P., Lewis, M. and Ross, M. (1994). “Crystal Structure Analysis for

Chemist and Biologist.” New York: VCH Publishers, Inc. 73-105.

20. Flanigen, E.M., Khatami, H., Szymanski, H.A. (1971). “Infrared Structural

Studies of Zeolite Frameworks.” In Flanigen, E.M. and Sand, L.B. (Eds.).

ACS Adv. Chem. Ser. 101. 201-227.

21. Fyfe, C.A. (1983). “Solid State NMR For Chemists.” Canada: C.F.C. Press. 337-

361.

22. Simonutti, R., Comotti, A., Bracco, S. and Sozzani, P. (2001). “Surfactant

Organization in MCM-41 Mesoporous Materials As Studied by 13C and 29Si

Solid State NMR.” Chem. Mater. 13. 771-777.

23. Leofanti, G., Padovan, M., Tozzola, G. and Venturelli, B. (1998). “Surface Area

Catal. Today. 41. 207-219.

24. McBain, J.W. (1932). “The Sorption of Gases and Vapors by Solids.” Rutledge,

London: ch. 5.

25. IUPAC Manual of Symbols and Terminology. (1978). Pure Appl. Chem. 31. 578.

128

26. Csicsery, S.M. (1984). “Shape-Selective Catalysis in Zeolites.” Zeolites. 4. 202-

213.

27. Beck, J.S., Vartuli, J.C., Roth, W.J., Leonowicz, M.E., Kresge, C.T., Schmitt,

K.D., Chu, C.T-w., Olson, D.H., Sheppard, E.W., McCullen, S.B., Hioggins, J.B.

and Schlenker, J.L. (1992). “A New Family of Mesoporous Molecular Sieves

Prepared with Liquid Crystal Templates.” J. Am. Chem. Soc. 114. 10834-10843.

28. Monnier, A., Schüth, F., Huo, Q., Kumar, D., Margolese, D., Maxwell, R.S.,

Stucky, G.D., Krishnamurty, M., Petroff, P., Firouzi, A., Janicke, M. and

Chmelka, B.F. (1993). “Cooperative Formation of Inorganic-Organic Interfaces

in the Synthesis of Silicate Mesostrutures.” Science. 261. 1299-1303.

29. Wouters, B.H., Chen, T., Dewilde, M. and Grobet, P.J. (2001). “Reactivity of the

Surface Hydroxyl Groups of MCM-41 Towards Silylation with

Trimethychlorosilane.” Microporous Mesoporous Mater. 44-45. 453-457.

30. Park, D.H., Nishiyama, N., Egashira, Y. and Ueyama, K. (2001). “Enhancement

of Hydrothermal Stability and Hydrophobicity of a Silica MCM-48 Membrane

by Silylation.” Ind. Eng. Chem. Res. 40. 6105-6110.

31. Zhao, X.S., Lu, Max G.Q. Lu and Song, C. (2003). “Immobilization of

Aluminum Chloride on MCM-41 as A New Catalyst System for Liquid -Phase

Isopropylation of Naphthalene.” J. Mol. Catal. A: Chemical. 191. 67–74.

32. Chen, C.Y., Li, H.X. and Davis, M.E. (1993). “Studies on Mesoporous

Materials: Synthesis and Characterization of MCM-41.” Microporous Mater. 2.

17-26.

33. Schoen, A.H. (1970). NASA Technical Note D-5541. Washington, DC.

129

34. Kosslick, H., Lischke, G., Walther, G., Storek, W., Martin, A. and Fricke, R.

(1997). “Physico-Chemical and Catalytic Properties of Al-, Ga- and Fe-

Substituted Mesoporous Materials Related to MCM-41.” Microporous Mater. 9.

13-33.

35. Schumacher, K., Ravikovitch, P.I., Chesne, A., Neimark, A.V. and Unger, K.K.

(2000). “Characterization of MCM- Langmuir. 16. 4648-4654.

36. Kim, J.M., Kim, S.K. and Ryoo., R. (1998). “Synthesis of MCM-48 Single

Crystals.” Chem. Comm. 259-260.

37. Anderson, M.W. (1997). “Simplified Description of MCM-48.” Zeolites. 19.

220-227.

38. Huo, Q., Margolese, D.I., Ciesla, U., Feng, P., Gier, T.E., Sieger, P., Leon, R.,

Petroff, P.M., Schuth, F. and Stucky, G.D. (1994). “Generalised Synthesis of

Periodic Surfactant-Inorganic Composite Materials.” Nature. 368. 317-323.

39. Huo, Q., Margolese, D.I., Ciesla, U., Demuth, D.G., Feng, P., Gier, T.E., Sieger,

P., Firouzi, A., Chmelka, B.F., Schuth, F. and Stucky, G.D. (1994).

“Organization of Organic Molecular with Inorganic Molecular Species into

Chem. Mater. 6. 1176-1191.

40. Wang, S., Wu, D., Sun, Y. and Zhong, B. (2001). “The Synthesis of MCM-48

with High Yields.” Mater. Res. Bull. 36. 1717-1720.

41. Yanagisawa, T., Shimizu, T., Kuroda, K. and Kaio, C. (1990). “The Preparation

of Alkyltrimethylammonium-Kanemite Complexes and Their Conversion to

Microporous Materials.” Bull. Chem. Soc. Jpn. 63. 988-992.

130

42. Tanev, P.T. and Pinnavaia, T.J. (1996). “Mesoporous Silica Molecular Sieves

Prepared by Ionic and Neutral Surfactant Templating: A Comparison of Physical

Properties.” Chem. Mater. 8. 2068-2079.

43. Bagshaw, S.A., Prouzet, E. and Pinnavaia, T.J. (1995). “Templating of

Mesoporous Molecular Sieves by Nonionic Polyethylene Oxide Surfactants.”

Science. 269. 1242-1244.

44. Behrens, P. (1996). “Voids in Variable Chemical Surroundings: Mesoporous

Angew. Chem. Int. Ed. Engl. 35. 515-518.

45. Zhao, D., Feng, J, Huo, Q., Melosh, N., Fredrickson, G.H., Chmelka, B.F. and

Stucky, G.D. (1998). “Triblock Copolymer Syntheses of Mesoporous Silica with

Periodic 50-300 Å Pores.”Science. 279. 548-552.

46. Kleitz, F., Choi, S.H. and Ryoo, R. (2003). “Cubic Ia3d Large Mesoporous

Silica: Synthesis and Replication to Platinum nanowires, Carbon Nanorods and

Carbon Nanotubes.” Chem. Comm. 2136-2137.

47. Huo, Q., Margolese, D.I. and Stucky, G.D. (1996). “Surfactant Control of Phases

in the Synthesis of Mesoporous Silica-Based Materials.” Chem. Mater. 8. 1147-

1160.

48. Gallis, K.W. and Landry, C.C. (1997). “Synthesis of MCM -48 by a Phase

Transformation Process.” Chem. Mater. 9. 2035-2038.

49. Lee, Y.S., Surjadi, D. and Rathman, J.F. (2000). “Compositional Effects and

Hydrothermal Reorganization of Mesoporous Silicates Synthesized in Surfactant

Solutions.” Langmuir. 16. 195-202.

131

50. Rocha, S.R. and Fernandes, L.D. (2001). “Synthesis of Mesoporous Molecular

Sieves MCM-48 Under Several Reaction Conditions.” 13th International Zeolite

Conference. July 8-13. Montpellier, France:06-P-24.

51. Behrens, P., Glaue, A., Haggenmüller, C. and Schechner, G. (1997). “Structure-

directed Materials Syntheses: Synthesis Field Diagrams for the Preparation of

Mesostructured Silicas.” Solid State Ionics. 101-103. 255-260.

52. Øye, G., Sjöblom, J. and Stöcker, M. (1999). “Synthesis and Characterization of

Siliceous and Aluminum-Containing Mesoporous Materials from Different

Surfactant Solutions.” Microporous Mesoporous Mater. 27. 171-180.

53. Xu, J., Luan, Z., He, H., Zhou, W. and Kevan, L. (1998). “A Reliable Synthesis

of Cubic Mesoporous MCM-48 Molecular Sieves.” Chem. Mater . 10. 3690-

3698.

54. Sayari, A. (2000). “Novel Synthesis of High-Quality MCM-48 Silica.” J. Am.

Chem. Soc. 122. 6504-6505.

55. Echchahed, B., Morin, M., Blais, S., Badiei, A.R., Berhault, G. and Bonneviot,

L. (2001). “Ion Mediation and Surface Charge Density in Phase Transition of

Microporous Mesoporous Mater. 44-45. 53-63.

56. Firouzi, A., Atef, F., Oertli, A.G., Stucky, G.D. and Chmelka, B.F. (1997).

“Alkaline Lyotropic Silicate-Surfactant Liquid Crystals.” J. Am. Chem. Soc. 119.

3596-3610.

57. Israelachvili, J.N., Mitchell, D.J. and Ninham, B.W. (1976). “Theory of Self-

Assembly of Hydrocarbon Amphiphiles into Micelles and Bilayers.” J. Chem.

Soc. Faraday Trans. 72. 1525-1568.

132

58. Peña, M.L., Kan, Q, Corma, A. and Rey, F. (2001). “Synthesis of Cubic

Mesoporous MCM-48 Materials from the System SiO2 : CTAOH/Br : H2O.”

Microporous Mesoporous Mater. 44-45. 9-16.

59. Schumacher, K., Grün, M. and Unger, K.K. (1999). “Novel Synthesis of

Spherical MCM-48.” Microporous Mesoporous Mater. 27. 201-206.

60. Chen, F., Song, F. and Li, Q. (1999). “Mixed Cationic-Anionic Templating

Route to Al-MCM-48.” Microporous Mesoporous Mater. 29. 305-310.

61. Kruk, M., Jaroniec, M., Ryoo, R. and Joo, S.H. (2000). “Characterization of

MCM-48 Silicas with Tailored Pore Sizes Synthesized via a Highly Efficient

Procedure.” Chem. Mater. 12. 1414-1421.

62. Song, M.G., Kim, J.Y., Cho, S.H. and Kim, J.D. (2002). “Mixed Cationic-

Nonionic Surfactant Templating Approach for the Synthesis of Mesoporous

Silica.” Langmuir. 18. 6110-6115.

63. Van Der Voort, P., Mathieu, M., Mees, F. and Vansant, E.F. (1998). “Synthesis

of High-Quality MCM-48 and MCM-41 by Means of the GEMINI Surfactant

Method.” J. Phys. Chem. B. 102. 8847-8851.

64. James, J. and Subba Rao, M. (1986). “Characterization of Silica in Rice Husk

Am. Ceram. Soc. Bull. 65. 1177-1180.

65. Chen, S.S. and Yeoh, A.K. (1992). “Development of Zeolite NaY from Rice

J. Ind. Tech. 2. SIRIM, Malaysia.

66. He, J., Yang, X.B., Evans, D.G. and Duan, X. (2002) “New Methods to Remove

Organic Templates from Porous Materials.” Mater. Chem. Phys.. 9277. 1-6.

133

67. Kleitz, F., Schmidt, W. and Schüth, F. (2001). “Evolution of Mesoporous

Materials during the Calcination Process: Structural and Chemical Behavior.”

Microporous Mesoporous Mater. 44-45. 95-109.

68. Bergna, H.E. (1994). “The Colloid Chemistry of Silica.” Washington: American

Chemical Society.

69. Moulijn, J. A., Van Leeuwen, P. W. N. M. and Van Santen, R. A. (1993).

“Preparation of Catalyst Supports and Zeolites.” Stud. Surf. Sci. Catal. 79. 111-

121.

70. Marler, B., Oberhagamann, U., Vortmann, S. and Gies, H. (1996). “Influence of

the Sorbate Type on the XRD Peak Intensities of Loaded MCM-41.”

Microporous Mater. 6. 375.

71. Iler, R.K. (1979). “The Chemistry of Silica. Solubility, Polymerization, Colloid

and Surface Properties, and Biochemistry.” New York: J. Wiley & Sons. 63-175.

72. Holland, P.M. and Rubingh, D.N. (1992). In “Mixed Surfactant Systems.”

Holland, P.M. and Rubingh, D.N. (Eds). Washington: American Chemical

Society. ACS Symposium Series. 501. 2-30.

73. Schüth, F. and Ciesla, U. (1999). “Ordered Mesoporous Materials.” Microporous

Mesoporous Mater. 27. 131-149.

74. Chenite, A., Le Page, Y. and Sayari, A. (1995). “Direct TEM Imaging of Tubules

in Calcined MCM-41 Type Mesoporous Materials.” Chem. Mater. 7. 1015.

75. Blin, J.L., Otjacques C., Herrier, G. and Su, B.L. (2001). “Kinetic Study of

MCM-41 Synthesis.” Int. J. Inorg. Mater. 3. 75-86.

134

76. Kruk, M., Jaroniec, M., Yang, Y. and Sayari, A. (2000). “Determination of the

Lamellar Phase Content in MCM-41 Using X-ray Diffraction, Nitrogen

Adsorption, and Thermogravimetry.” J. Phys. Chem. B. 104. 1581-1589.

77. Kruk, M., Jaroniec, M., Lourdes Peña, M. and Rey, F. (2002). “Determination of

Phase Composition of MCM-48/Lamellar Phase Mixtures Using Nitrogen

Adsorption and Thermogravimetry.” Chem. Mater. 14. 4434-4442.

78. Pfeifer, H., Freude, D. and Hunger, M. (1985). “Nuclear Magnetic Resonance

Studies on the Acidity of Zeolites and Related Catalysts.” Zeolites. 5. 274-286.

79. Schmidt, R., Stöcker, M., Akporiaye, D., Tørstad, E.H. and Olsen, A. (1995).

“High-Resulation Electron Microscopy and X-Ray Diffraction Studies of MCM-

48.” Microporous Mater. 5. 1-7.

80. Vartuli, J.C., Schmitt, K.D., Kresge, C.T., Roth, W.J., Leonowicz, M.E.,

McCullen, S.B., Hellring, S.D., Beck, J.S., Schlenker, J.L., Olson, D.H. and

Sheppard, E.W. (1994). Chem. Mater. 6. 2317.

81. Borade, R.B. and Clearfield, A. (1995). “Synthesis of Aluminum Rich MCM-

41.” Catal. Lett. 31. 267-272.

82. Yue, Y., Sun, Y., Xu, Q. and Gao, Z. (1998). “Catalytic Activities and Properties

of AlHMS Mesoporous Molecular Sieves.” Appl. Catal. A: General. 175. 131-

137.

83. Romero, A.A., Alba, M.D. and Klinowski, J. (1998). “Aluminosilicate

Mesoporous Molecular Sieve MCM-48.” J. Phys. Chem. B. 102. 123-128.

84. Chen, L.Y., Ping, Z., Chuah, G.K., Jaenicke, S. and Simon, G. (1999). “A

Comparison of Post-Synthesis Alumination and Sol-Gel Synthesis of MCM-41

135

with High Framework Aluminum Content.” Microporous Mesoporous Mater.

27. 231-242.

85. Kodenev, E.G., Shmakov, A.N., Derevyankin, A.Y., Lapina, O.B. and

Romannikov, V.N. (2000). “Highly-Ordered Aluminosilicate Mesoporous

Mesophase Materials: Physico-Chemical Properties and Catalytic Behaviour.” J.

Mol. Catal. A: Chemical. 158. 349-354.

86. Lindlar, B., Kogelbauer, A. and Prins, R. (2000). “Chemical, Structural, and

Catalytic Characteristics of Al-MCM-41 Prepared by pH-Controlled Synthesis.”

Microporous Mesoporous Mater. 38. 167-176.

87. Hu, X., Chuah, K., and Jaenicke, S. (2001). “Room Temperature Synthesis of

Diphenylmethane over MCM-41 Supported AlCl3 and Other Lewis Acids.” Appl.

Catal. A: General. 217. 1-9.

88. Ahn, W.S., Lee, D.H., Kim, T.J., Kim, J.H., Seo, G. and Ryoo, R. (1999). “Post-

Synthetic Preparations of Titanium-Containing Mesopore Molecular Sieves.”

Appl. Catal. A: General. 181. 39-49.

89. Gianotti, E., Dellarocca, V., Marchese, L., Martra, G., Coluccia, S. and

Maschmeyer, T. (2002). “NH3 Adsorption on MCM-41 and Ti-Grafted MCM-

41: FTIR, DR UV-Vis-NIR and Photoluminescence Studies.” Phys. Chem.

Chem. Phys. 4. 6109-6115.

90. Stockenhuber, M., Joyner, R.W., Dixon, J.M., Hudson, M.J. and Grubert, G.

(2001). “Transition Metal Containing Mesoporous Silicas-Redox Properties,

Structure and Catalytic Activity.” Microporous Mesoporous Mater. 44-45. 367-

375.

136

91. Köhn, R., and Fröba, M. (2001). “Nanoparticles of 3d Transition Metal Oxides in

Mesoporous MCM-48 Silica Host Structures: Synthesis and Characterization.”

Catal. Today. 68. 227-236.

92. Ryoo, R., Jun, S., Kim, J.M. and Kim, M.J. (1997). “Generalised Route to the

Preparation of Mesoporous Metallosilicates via Post-Synthetic Metal

Implantation.” Chem. Comm. 2225-2226.

93. Peña, M.L., Dejoz, A., Fornés, V., Rey, F., Vázquez, M.I. and López Nieto, J.M.

-Containing MCM-41 and MCM-48 Catalysts for the Selective

Oxidation of Propane in Gas Phase.” Appl. Catal. A: General . 209. 155-164.

94. Yuan, Z.Y., Wang, J.Z., Zhang, Z.L., Chen, T.H. and Li, H.X. (2001).

“Vanadium- and Chromium-Containing Mesoporous MCM-41 Molecular Sieves

with Hierarchical Structure.” Microporous Mesoporous Mater. 43. 227-236.

95. Morey, M.S., Stucky, G.D., Schwarz, S. and Fröba, M. (1999). “Isomorphic

Substitution and Postsynthesis Incorporation of Zirconium into MCM-48

Mesoporous Silica.” J. Phys. Chem. B. 103. 2037-2041.

96. Hartmann, M., Bischof, C., Luan, Z. and Kevan, L. (2001). “Preparation and

Characterization of Ruthenium Clusters on Mesoporous Supports.” Microporous

Mesoporous Mater. 44-45. 385-394.

97. Tismaneanu, R., Ray, B., Khalfin, R., Semiat, R. and Eisen, M.S. (2001).

“Synthesis, Characterization and Catalytic Activity of Actinide Th-MCM-41 and

U-MCM-41 Hexagonal Packed Mesoporous Molecular Sieves.” J. Mol. Catal. A:

Chemical. 171. 229-241.

137

98. Gauthier, C., Chiche, B., Finiels, A. and Geneste, P. (1988). “Influence of

Acidity in Friedel-Crafts Acylation Catalyzed by Zeolites.” Mol. Catal. A. 50.

219-229.

99. On, D.T., Desplantier-Giscard, D., Danumah, C. and Kaliaguine, S. (2001).

“Perspectives in Catalytic Applications of Mesostructured Materials.” Appl.

Catal. A: General. 222. 299-357.

100. Du, H., Terskikh, V.V., Ratcliffe, C.I. and Ripmeester, J.A. (2002).

“Distinguishing Surface versus Buried Cation Sites in Aluminosilicate

J. Am. Chem. Soc. 124. 4216-4217.

101. Endud, S. (2000). “Secondary Aluminated Mesoporous Molecular Sieves Al-

MCM-41: Synthesis, Characterization and Catalytic Activity.” Universiti

Teknologi Malaysia: Ph.D. Thesis.

102. Barrett, E.P., Joyner, L.G. and Halenda, P.P. (1951). J. Am. Chem. Soc. 73. 373.

103. Feuston, B.P. and Higgins, J.B. (1994). “Model Structures for MCM-41

Materials.” J. Phys. Chem. 98. 4459-4462.

104. Branton, P.J., Hall, P.J., Sing, K.S.W., Reichert, H., Schuth, F. and Unger, K.K.

(1994). “Physisorption of Argon, Nitrogen and Oxigen by MCM-41, a Model

Mesoporous Adsorbent.” J. Chem. Soc. Faraday Trans. 90. 2965-2967.

105. Gregg, S.J. and Sing, K.S.W. (1982). “Adsorption, Surface and Porosity.” 2nd Ed.

New York.

106. Sonwane, C.G. and Bhatia, S.K. (2000). “Characterization of Pore Size

Distributions of Mesoporous Materials from Adsorption Isotherms.” J. Phys.

Chem. B. 104. 9099-9110.

138

107. Ryoo, R., Ko, C.H. and Howe, R.F. (1997). “Imaging the Distribution of

Framework Aluminum in Mesoporous Molecular Sieve MCM-41.” Chem.

Mater. 9. 1607-1613.

108. Weglarski, J., Datka, J., He, H. and Klinowski, J. (1996). “IR Spectroscopic

Studies of the Acidic Properties of the Mesoporous Molecular Sieve MCM-41.”

J. Chem. Soc. Faraday Trans. 92. 5161-5164.

109. Corma, A. (1997). “From Microporous to Mesoporous Molecular Sieve

Materials and Their Use in Catalysis.” Chem. Rev. 97. 2373-2419.

110. Corma, A., Fornes, V., Navarro, M.-T. and Periente, J.P. (1994). “Acidity and

Stability of MCM-41 Crystalline Aluminosilicates.” J. Catal. 148. 569-574.

111. Barrer, R.M. (1982). “Hydrothermal Chemistry of Zeolite.” London: Academic

Press.

112. Van Bekkum, H., Flanigen, E.M. and Jansen, J.C. (1991). “An Introduction to

Stud. Surf. Sci. Catal. 58. 201-239.

113. Dwyer, J. (1992). “Evolution and Tailoring of Acid-Base Properties of Zeolites

Part 1.” Zeolites Microporous Solids: Synthesis, Structure and Reactivity. 303-

319.

114. Lercher, J.A., Gründling, C. and Eder-Mirth, G. (1996). “Infrared Studies of the

Surface Acidity of Oxides and Zeolites Using Adsorbed Probed Molecules.”

Catal. Today. 27. 351-376.

115. Uytterhoeven, J.B., Christner, L.G. and Hall, W.K. (1965). “Studies of the

Hydrogen Held by Solids. VIII. The Decationated Zeolites.” J. Phys. Chem . 69.

2117-2126.

139

116. Hughes, T.R. and White, H.M. (1967). “A Study of the Surface Structure of

Decationized Y Zeolite by Quantitative Infrared Spectroscopy.” J. Phys. Chem.

71. 2192-2201.

117. Olah, G.A. (1973). “Friedel-Crafts Chemistry.” USA: John Wiley and Sons. 28-

46.

118. Andy, P., Garcia-Martinez, J., Lee, G., Gonzalez, H., Jones, C.W. and Davis,

M.E. (2000). “Acylation of 2-Methoxynaphthalene and Isobutylbenzene over

Zeolite Beta.” J. Catal. 192. 215-223.

119. Cheralathan, K.K., Sudarsan Kumar, I., Arabindoo, B., Palanichamy, M. and

Murugesan, V. (2001). “Facile Friedel-Craft's Alkylation of Phenol with 4-

Hydroxybutan-2-one over β and Y Zeolites to Produce Raspberry Ketone.” 13th

International Zeolite Conference. July 8-13. Montpellier, France: 25-O-02.

120. Gaare, K. and Akporiaye, D. (1996). “Modified Zeolites As Catalysts in the

Friedal-Crafts Acylation.” J. Mol. Catal. A: Chemical. 109. 177-187.

121. Davis, M.E. (1998). “Zeolite-based Catalysts for Chemicals Synthesis.”

Microporous Mesoporous Mater. 21. 173-182.

122. Fromentin, E., Coustard, J.-M. and Guisnet, M. (2000). “Mechanism of 1-Acetyl-

2-methoxynaphthalene Isomerisation over a HBEA Zeolite.” J. Catal . 190. 433-

438.

123. Kapustin, G.I., Brueva, T.R. and Klyachko, A.L. (1988). “Detrmination of the

Number and Acid Strength of Acid Sites in Zeolites by Ammonia Adsorption.

Comparison of Calorimetry and Temperature Programmed Desorption of

Ammonia.” Appl. Catal. 42. 239-246.

140

124. Chakraborty, B. and Viswanathan, B. (1999). “Surface Acidity of MCM-41 by in

situ IR Studies of Pyridine Adsorption.” Catal. Today. 49. 253-260.