Heterogeneously Catalyzed Oxidation Reactions Using ... - CHEC

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CHAPTER 5 Table 5‐5: Experimental dew points for relevant ternary mixtures between 60‐80 °C. Temperature (°C) Phigh a Plow b 0.45 ± 0.02 mol‐% benzyl alcohol, 0.16 ± 0.02 mol‐% oxygen and 99.39 ± 0.02 mol‐% CO2 60 ± 0.5 123.0 ± 1.9 122.0 ± 1.9 122.5 ± 2.4 70 ± 0.5 133.0 ± 4.1 132.0 ± 3.9 132.6 ± 4.5 80 ± 0.5 140.0 ± 2.5 139.0 ± 3.1 139.2 ± 3.3 0.60 ± 0.02 mol‐% benzyl alcohol, 0.30 ± 0.02 mol‐% oxygen and 99.10 ± 0.02 mol‐% CO2 60 ± 0.5 151.5 ± 1.7 150.5 ± 2.3 150.7 ± 2.5 0.91 ± 0.02 mol‐% benzyl alcohol, 0.43 ± 0.02 mol‐% oxygen and 98.66 ± 0.02 mol‐% CO2 60 ± 0.5 133.0 ± 3.3 132.0 ± 3.5 132.4 ± 3.9 70 ± 0.5 150.0 ± 3.3 149.0 ± 3.9 149.2 ± 4.1 80 ± 0.5 163.0 ± 3.5 162.0 ± 3.5 162.5 ± 4.0 138 Psep c 0.45 ± 0.02 mol‐% benzaldehyde, 0.45 ± 0.02 mol‐% H2O and 99.10 ± 0.02 mol‐% CO2 60 ± 0.5 105.0 ± 1.7 104.0 ± 1.3 104.7 ± 2.0 80 ± 0.5 110.0 ± 1.1 109.0 ± 2.1 109.0 ± 2.1 0.90 ± 0.02 mol‐% benzaldehyde, 0.90 ± 0.02 mol‐% H2O and 98.20 ± 0.02 mol‐% CO2 60 ± 0.5 112.0 ± 2.5 111.0 ± 2.5 111.5 ± 3.0 80 ± 0.5 133.0 ± 2.5 131.0 ± 1.5 132.5 ± 3.0 a Average high pressure limit; b Average low pressure limit; c Pressure interval for phase separation. The results are shown in Table 5‐5. Comparing the experimental data with the model (Figure 5‐3a) showed that the dew point pressures were slightly overestimated. Nevertheless, especially at low benzyl alcohol concentrations, the model was in reasonable agreement with the experimental data. Similar observations were made for the ternary mixture representing the product mixture (Figure 5‐ 3b). In general, the pressure required for the reaction mixture to exist as a single phase is higher for the mixture corresponding to 0 % conversion. At an assumed conversion of 50 % (with 100 % selectivity) the dew point of the mixture also occurred at a lower pressure. The role of oxygen was further studied being both the oxidant and influencing the dew point (Figure 5‐4). With increasing oxygen concentration, the dew point is increasing. Within a range relevant for the catalytic oxidation reaction, the influence of oxygen on the dew point is much smaller compared to the influence of the benzyl alcohol concentration.
Pressure (bar) 150 145 140 135 5.3 Results 130 0.0 0.4 0.8 1.2 1.6 2.0 O 2 (mol-%) Figure 5‐4: Influence of the oxygen concentration on the dew point (conditions: 0.45 mol‐% benzyl alcohol, O2 as indicated, rest CO2; 80 °C). 5.3.4 Benzyl alcohol oxidation as a function of pressure The oxidation of benzyl alcohol was studied with pressurized CO2 as the solvent with a commercial shell‐impregnated 0.5 wt.‐% Pd/Al2O3 catalyst in a fixed bed reactor. By using a shell‐impregnated catalyst, internal mass transport effects were minimized. Due to the tunability of the CO2 solvent properties, the pressure plays an important role in this type of reaction. Figure 5‐5 shows the dew points of substrate and product mixtures obtained from CPA modeling at 80 °C with different benzyl alcohol/benzaldehyde concentrations in stoichiometric mixtures with oxygen and water, Figure 5‐5: Dew points of stoichiometric benzyl alcohol (benzaldehyde) – O2 (water) in CO2 mixtures at 80 °C. 139
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TECHNICAL UNIVERSITY OF DENMARK (DT
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Preface The present dissertation su
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the carboxylic acid, ceria inhibite
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Resume Denne afhandling giver indle
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hvorimod mængden af katalysator ku
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2.3.8 Oxidation of sulfides .......
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5.3.5 Macroscopic mass transport in
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Chapter 1 Introduction With its gre
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1. Introduction Scheme 1‐1: High
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1. Introduction Figure 1‐2: Phase
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1. Introduction [28] S. Bawaked, N.
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2.1 Introduction 2.1 Introduction E
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2.2.1 Synthesis of gold catalysts 2
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2.2 Catalyst synthesis for oxidatio
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2.2 Catalyst synthesis for oxidatio
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2.3 Selective liquid‐phase oxidat
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Table 2-1: Overview over alcohol ox
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Ph O O Ph (4) (5) 2.3 Selective liq
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Table 2-4: Side-chain oxidation of
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2.3.4 Oxidation of cyclohexane 2.3
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Table 2-5: Oxidatin of cyclohexane.
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Table 2-6: Ring hydroxylation of ar
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Table 2-7: Aerobic oxidation of ami
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Table 2-8: Oxidation of hydroquinon
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Table 2-9: Oxidation of silanes wit
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Table 2-10: Oxidation reactions cat
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2.4 Strengths and opportunities of
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2.6 References 2.6 References [1] M
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2.6 References [56] H. Tumma, N. Na
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2.6 References [113] C. Keresszegi,
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2.6 References [169] Q. Zhu, Y. Lia
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2.6 References [223] M. Fetizon, M.
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Chapter 3 Selective Liquid-Phase Ox
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3.2 Experimental 3.2.1 Catalyst pre
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3.3 Results Scattering amplitudes a
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Absorption (a.u.) 1.2 1.0 0.8 0.6 0
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Conversion (%) 100 90 80 70 60 50 4
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Page 103 and 104: 3.3 Results Table 3‐2: Conversion
Page 105 and 106: 3.3 Results In order to gain insigh
Page 107 and 108: 3.3 Results the cost of selectivity
Page 109 and 110: 3.4 Discussion synergetic interacti
Page 111 and 112: 3.5 Conclusions to corroborate the
Page 113 and 114: 3.6 References [29] T. Mitsudome, Y
Page 115 and 116: Chapter 4 Selective Side-Chain Oxid
Page 117 and 118: 4.2 Experimental single‐step flam
Page 119 and 120: 4.2 Experimental alcohol (Aldrich,
Page 121 and 122: 4.3 Results Scheme 4‐1: Oxidation
Page 123 and 124: 4.3 Results Figure 4‐2: Formation
Page 125 and 126: 4.3 Results oxidation by either 2,6
Page 127 and 128: Absorption (a.u.) Absorption (a.u.)
Page 129 and 130: 4.3 Results atomic mixing of Ag and
Page 131 and 132: 4.3 Results Figure 4‐7: Influence
Page 133 and 134: 4.4 Discussion and mechanistic cons
Page 135 and 136: 4.5 Conclusions heterogeneous radic
Page 137 and 138: 4.6 References [29] S.I. Zabinsky,
Page 139 and 140: Chapter 5 Experimental Determinatio
Page 141 and 142: 5.2 Experimental The most important
Page 143 and 144: 5.2 Experimental Eurotherm 2216e te
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Page 147 and 148: (Eq. 5‐5) AB i j ε AB i j β 5.2
Page 149 and 150: (a) (b) (c) (d) (e) (f) (g) (h) (i)
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Page 155 and 156: 5.3 Results Figure 5‐7: Oxidation
Page 157 and 158: Weight (g) 5.3 Results Figure 5‐8
Page 159 and 160: 5.4 Discussion catalytic reactions
Page 161 and 162: 5.4 Discussion corresponding CO2‐
Page 163 and 164: 5.5 Conclusions 5.5 Conclusions The
Page 165 and 166: 5.6 References [29] I. Tsivintzelis
Page 167 and 168: 6.1 Introduction 6.1 Introduction A
Page 169 and 170: 6.2 Experimental [38]. In a typical
Page 171 and 172: 6.3 Results out in 1 mm quartz tube
Page 173 and 174: 6.3 Results Figure 6‐2: Structure
Page 175 and 176: 6.3 Results Figure 6‐4: Epoxidati
Page 177 and 178: 6.3 Results Figure 6‐6: Compariso
Page 179 and 180: 6.3 Results Figure 6‐8: Influence
Page 181 and 182: 6.3 Results investigated the epoxid
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Page 185 and 186: 6.3 Results Figure 6‐11: EXAFS an
Page 187 and 188: 6.4 Discussion would need to be for
Page 189 and 190: 6.5 Conclusions Formation of the ep
Page 191 and 192: 6.6 References [28] J. Perles, N. S
Page 193 and 194: Chapter 7 Concluding Remarks 7.1 Co
Page 195 and 196: 7.2 Final remarks and outlook speci
Page 197 and 198: Acknowledgements Acknowledgements T
Page 199: Curriculum Vitae Matthias Josef Bei
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