고체 산촉매를 이용한 글리세롤의 기상 탈수화반응
Gas-phase dehydration of glycerol over solid acid catalysts
- 주제(키워드) Dehydration , Glycerol , Acrolein , Solid acid catalysts
- 발행기관 아주대학교
- 지도교수 박은덕
- 발행년도 2011
- 학위수여년월 2011. 2
- 학위명 박사
- 학과 및 전공 일반대학원 에너지시스템학부
- 파일정보 word
- 실제URI http://www.dcollection.net/handler/ajou/000000011224
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
The gas-phase dehydration of glycerol was examined for the production of acrolein over solid acid catalysts, viz. zeolites, metal oxides and supported heteropoly acids (HPAs). Several techniques: N2-physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), temperature-programmed desorption of ammonia, carbon dioxide and water (NH3-TPD, CO2-TPD and H2O-TPD) with mass spectroscopy, temperature-programmed oxidation (TPO) with mass spectroscopy, infrared spectroscopy (FT-IR) after pyridine adsorption and glycerol adsorption, thermogravimetric analysis (TG), differential scanning calorimetry (DSC), CHNS analysis, 29Si and 27Al MAS NMR and Raman analysis were employed to characterize the catalysts. The metal oxides viz. g-Al2O3, SiO2-Al2O3, TiO2, ZrO2, SiO2, AC, CeO2 and MgO on the catalytic performance is intensively examined. SiO2-Al2O3 showed the highest glycerol dehydration activity at 315 ℃ among the tested metal oxides because of its the larger amount of strong acid sites [52]. CeO2 showed the highest 1-hydroxyacetone selectivity at 315 ℃ among the various metal oxides [52]. The silica-aluminas with the variation of Al content were examined over the dehydration of glycerol. For comparison, SiO2 and h-Al2O3 were also examined. Si0.4Al0.6Ox showed the highest glycerol conversion, whereas Si0.8Al0.2Ox showed the highest acrolein selectivity at 315 ℃ among the tested catalysts. The H(Na)-zeolites viz. H(Na)-ZSM-5, H-b, H-ferrierite, H-Y and H-mordenite were carried out over the dehydration of glycerol. For comparison, g-Al2O3 and SiO2-Al2O3 were also examined. H-Zeolites such as H-ZSM-5, H-b and H-ferrierite with various SiO2/Al2O3 ratios were also examined over the dehydration of glycerol. It is implies that the catalytic performance can be closely influenced by the SiO2/Al2O3 ratio, which changed the physicochemical properties for H-zeolites [39, 40]. Among all of the tested H-zeolites, H-ZSM-5 with SiO2/Al2O3 ratio of 150 showed the highest glycerol conversion and acrolein selectivity at 315 ℃ [39]. The metal oxide supported HSiW catalysts were carried out over the dehydration of glycerol. HSiW/ZrO2 and HSiW/SiO2-Al2O3 showed the highest acrolein selectivity at 315 ℃ among the tested HSiW catalyst [52]. The silica-alumina supported HSiW catalysts were carried out over the dehydration of glycerol. HSiW/Si0.8Al0.2Ox showed the highest glycerol dehydration activity at 315 ℃ among the tested HSiW catalysts.
more목차
Ⅰ INTRODUCTION 1
Ⅱ REVIEW OF RELATED LITERATURE 7
2.1 LIQUID-PHASE DEHYDRATION OF GLYCEROL 8
2.2 GAS-PHASE DEHYDRATION OF GLYCEROL 10
2.2.1 Zeolites 11
2.2.2 Heteropolyacids (HPAs) 13
Ⅲ OBJECTIVE OF STUDY 16
Ⅳ EXPERIMENTAL METHODS 19
4.1 PREPARATION OF CATALYST 19
4.1.1 Zeolites 19
4.1.2 Metal oxides and supported silicotungstic acids (H4SiW12O40xH2O) 22
4.1.3 Silica-aluminas and supported silicotungstic acids (H4SiW12O40xH2O) 22
4.2 CATALYST CHARACTERIZATION 23
4.2.1 N2-physisorption 23
4.2.2 X-ray diffraction (XRD) 24
4.2.3 Scanning electron microscopy (SEM) 26
4.2.4 The temperature-programmed techniques (TPT) 26
4.2.5 Fourier-transform infrared spectroscopy (FT-IR) 27
4.2.6 Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) 28
4.2.7 Elemental CHNS analysis 29
4.2.8 Solid state 29Si and 27Al magic-angle spinning nuclear magnetic resonance (MAS NMR) 29
4.2.9 Raman spectroscopy 29
4.3 CATALYTIC PERFORMANCE TESTS 30
Ⅴ RESULTS AND DISCUSSION 35
5.1 CATALYST CHARACTERIZATION 35
5.1.1 Metal oxides 35
5.1.2 Silica-aluminas 37
5.1.3 Zeolites 43
5.1.4 Metal oxide supported silicotungstic acids (H4SiW12O40xH2O) 51
5.1.5 Silica-alumina supported silicotungstic acids (H4SiW12O40xH2O) 53
5.2 GAS- PHASE REACTION 55
5.2.1 Activity comparison 55
5.2.1.1 Metal oxides 55
5.2.1.2 Silica-aluminas 56
5.2.1.3 Zeolites 60
5.2.1.4 Metal oxide supported silicotungstic acids (H4SiW12O40xH2O) 68
5.2.1.5 Silica-alumina supported silicotungstic acids (H4SiW12O40xH2O) 70
5.2.2 Catalytic stability 76
5.2.3 Characterization of spent catalysts 79
5.2.4 Effect of process parameters 84
5.2.4.1 The effect of reaction temperature on H-zeolites 84
5.2.4.2 The effect of glycerol concentration on H-zeolites 88
5.2.4.3 The effect of water concentration 90
5.2.4.4 The effect of contact time on H-zeolites 95
5.2.5 Effect of physicochemical properties 97
5.2.6 Guidelines for regeneration of the catalysts 100
5.2.6.1 Cyclic regeneration 100
5.2.6.2 Co-feeding of molecular oxygen (or hydrogen) with the feed 102
5.2.7 Reaction mechanism 104
Ⅵ CONCLUSION 107
APPENDIX A: The temperature-programmed desorption of NH3 (NH3-TPD) 109
APPENDIX B: X-ray diffraction (XRD) 115
APPENDIX C: Pore size distribution 117
APPENDIX D: Scanning electron microscopy (SEM) 118
APPENDIX E: Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC) 119
APPENDIX F: Characterization of the used catalysts 122
REFERENCE 128
