Heterogeneously Catalyzed Oxidation Reactions Using ... - CHEC

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a.u. CHAPTER 6 Figure 6‐1: Characteristic XRD pattern of the newly synthesized STA‐12(Co) MOF compared to STA‐12(Ni) [36] in the as‐prepared state. The structure of STA‐12(Co) was refined by the Rietveld method, using the GSAS suite of programs [44], against laboratory powder X‐ray diffraction data (Fe Kα1, λ = 1.930642 Å). The structure of as‐ prepared STA‐12(Ni) was used as the starting model, with the cell derived from Le Bail fitting. Positions of physisorbed water molecules were retained from STA‐12(Ni) and the reduced amount of physisorbed water accounted for by changes in the occupancies of water sites. The final profile fit shows good agreement with the observed diffraction pattern indicating STA‐12(Co) to be isostructural (Figure 6‐2) with STA‐12(Ni). The porosity of STA‐12(Co) was confirmed by N2 adsorption at 77 K on dehydrated samples of STA‐12(Co). Samples were activated at 140 °C for 180 minutes and found to have a pore volume of 0.10 cm 3 g ‐1 (at p/p0 = 0.4). Synthesis and the characterization of the MOF material was done by Michael T. Wahrmby and Paul A. Wright from the University of St. Andrews (UK). 158
6.3 Results Figure 6‐2: Structure of STA‐12(Co) as obtained from Rietveld refinement. 6.3.2 STA-12(Co) as heterogeneous epoxidation catalyst in DMF The Co‐based metal‐organic framework was used as an epoxidation catalyst in DMF with molecular oxygen as the oxidant. In a first set of experiments, the epoxidation of styrene was investigated giving styrene oxide, benzaldehyde and benzoic acid as the major products detectable by GC accounting for roughly 60 % of the mass balance. The rate of product formation increased steadily in the beginning of the reaction comprising a noticeable induction phase of ca. 30 min (Figure 6‐3). The reaction was complete after 5 h and exhibited only a very low selectivity of 21 % to styrene oxide. Roughly twice the amount of N‐formyl‐N‐methylformamide (FMF) was formed during the reaction with respect to converted styrene. The incomplete mass balance obtained from GC analysis throughout the reaction might be accounted for by styrene oligomerization. Thus, (E)‐stilbene was used being less prone to oligomerization for further studies. (E)‐stilbene was readily converted to trans‐stilbene oxide (Figure6‐4) the mass balance from GC analysis being close to 100 %. Almost full conversion was obtained after 12 h and an FMF amount of about 1.6 times the converted stilbene 159
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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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3.3 Results Figure 3‐5: In situ X
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3.3 Results Table 3‐2: Conversion
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3.3 Results In order to gain insigh
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3.3 Results the cost of selectivity
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3.4 Discussion synergetic interacti
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3.5 Conclusions to corroborate the
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3.6 References [29] T. Mitsudome, Y
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Chapter 4 Selective Side-Chain Oxid
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4.2 Experimental single‐step flam
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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
Page 145 and 146: Figure 5-1: Schematic view of the e
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)
Page 151 and 152: 5.3 Results two association sites o
Page 153 and 154: Pressure (bar) 150 145 140 135 5.3
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: 6.3 Results out in 1 mm quartz tube
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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