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Table of contents
CHAPTER 1. BIBLIOGRAPHIC REPORT
1.1 Applications of ASAs in catalysis
1.2 Brønsted and Lewis acidity in ASA
1.2.1 Brønsted acid sites
1.2.2 Lewis acid sites
1.3 Formation of ASA
1.4 Acidity Characterization
1.4.1 Characterization of the structure of the acid sites
1.4.1.1 SSNMR
1.4.1.2 FTIR
1.4.2 Quantitative evaluation of the acid sites
1.4.2.1 TPD (NH3 and other bases)
1.4.2.2 FTIR of adsorbed probe molecules
1.4.2.3 Quantification of Protons
1.5 Model reaction for Brønsted acidity: Isomerization of 33DMB1
1.6 Reactivity of aluminosilicates toward water
1.6.1 Role of water on aluminium coordination
1.6.2 Role of water to acidity and reactivity
1.7 Objective and scope of this work
CHAPTER 2. EXPERIMENTAL AND CHARACTERIZATION
2.1 Materials
2.1.1 Commercial ASA
2.1.2 Commercial silica gel
2.1.3 Preparation of high surface area silica
2.2 Characterization
2.2.1 XRF
2.2.2 XRD
2.2.3 TGA
2.2.4 N2 physisorption
2.2.5 NH3-TPD
2.2.6 FTIR
2.2.6.1 FTIR of adsorbed pyridine
2.2.6.2 FTIR of adsorbed CO
2.2.7 Solid state NMR
2.2.7.1 1D MAS NMR
2.2.7.2 Quantification Proton
2.2.7.3 Homonuclear NMR
2.2.7.4 Heteronuclear NMR
2.2.8 Isomerization of 33DMB1 reaction
CHAPTER 3. DEALUMINATION OF AMORPHOUS SILICA-ALUMINAS WITH ACETYLACETONE AND ITS INFLUENCE ON ACIDITY AND ACTIVITY
3.1 Introduction
3.2 Experimental
3.2.1 Synthesis
3.2.1.1 Starting ASA
3.2.1.2 ASA dealuminated with acetylacetone
3.2.2 Characterization and catalytic test conditions
3.3 Results
3.3.1 Textural properties
3.3.2 Acidic Properties
3.3.3 Catalytic Performance
3.3.4 Aluminium coordination
3.3.5 Hydroxyl groups
3.4 Discussion
3.5 Conclusion
CHAPTER 4. DEALUMINATION OF AMORPHOUS SILICA-ALUMINAS WITH CITRIC ACID AND ITS INFLUENCE ON ACIDITY AND ACTIVITY
4.1 Introduction
4.2 Experimental
4.2.1 Synthesis
4.2.1.1 Starting ASA
4.2.1.2 ASA dealuminated with citric acid
4.2.2 Characterization and catalytic test conditions
4.3 Results
4.3.1 Effect of dealumination on composition (Si/Al ratio) and texture
4.3.2 Acidic Properties
4.3.2.1 NH3-TPD
4.3.2.2 FTIR of adsorbed pyridine
4.3.2.3 FTIR of adsorbed CO
4.3.2.4 Characterization of the acidic properties: conclusion
4.3.3 Catalytic Performance for the isomerization of 3,3-dimethylbut-1-ene
4.3.4 Aluminium coordination
4.3.5 Hydroxyl groups
4.4 Discussion
4.4.1 Mechanism of dealumination with CA
4.4.2 Effect of dealumination on the acidic properties of the ASA
4.5 Conclusion
CHAPTER 5. IDENTIFICATION OF THE ACID SITES ON DEALUMINATED AMORPHOUS SILICA-ALUMINAS BY SOLID STATE NMR
5.1 Introduction
5.1 Experimental
5.1.1 Synthesis
5.1.2 Characterization
5.2 Results
5.2.1 Brief overview of the characteristics of the selected ASAs
5.2.2 Characterization of the ammonium form ASA
5.2.2.1 27Al MAS NMR
5.2.2.2 1H MAS NMR spectra of ammonium ASA
5.2.2.3 Heteronuclear 27Al-1H MAS NMR
5.2.3 Characterization of H form ASA
5.2.3.1 27Al MAS NMR
5.2.3.2 1H MAS NMR
5.2.3.3 Heteronuclear 27Al-1H NMR
5.3 Summary of NMR results
5.3.1 NMR results on ammonium forms of the ASAs:
5.3.2 NMR results on H forms of the ASAs:
5.4 Discussion and conclusion
CHAPTER 6. SYNTHESIS OF ASA WITH IMPROVED ACIDITY BY GRAFTING OF AL PRECURSORS
6.1 Introduction
6.1.1 Parameters relevant for a controlled grafting of isolated Al
6.1.1.1 Characteristics of the silica support
6.1.1.2 Choice of the Al precursor
6.1.1.3 Conditions for grafting
6.1.2 Objectives
6.2 Experimental
6.2.1 Synthesis
6.2.1.1 Grafting Al(OPri)3 and substituted aluminium alkoxides
6.2.1.2 Grafting of Triisobutylaluminium (TiBA)
6.2.1.3 Grafting of Diisobutylaluminium hydride (DiBAH)
6.2.2 Characterization and catalytic test conditions
6.3 Results
6.3.1 ASA grafted with Al(OPri)xL3-x
6.3.1.1 Composition and textural properties
6.3.1.2 Acidic Properties
6.3.1.3 Aluminium coordination
6.3.1.4 Hydroxyl groups
6.3.1.5 Conclusion
6.3.2 ASA Grafted TiBA
6.3.2.1 Composition and porous properties
6.3.2.2 Acidic Properties
6.3.2.3 Aluminium coordination
6.3.2.4 Hydroxyl groups
6.3.2.5 Conclusion
6.3.3 ASA Grafted DiBAH
6.3.3.1 Composition and porous properties
6.3.3.2 Acidic Properties
6.3.3.3 Aluminium coordination
6.3.3.4 Hydroxyl groups
6.3.3.5 27Al-1H D-HMQC 2D NMR
6.3.3.6 Conclusion
6.3.4 Catalytic Performance for the isomerization of 3,3-dimethylbut-1-ene
6.4 Discussion
6.5 Conclusion and perspectives
