Heterogeneously Catalyzed Oxidation Reactions Using ... - CHEC

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CHAPTER 2 temperatures (60 °C) than with gold and afforded ketones from primary amines [204]. Dehydroascorbic acid was assumed to be the primary oxidant. These two Cu systems demonstrate the principal feasibility of Cu as an amine oxidation catalyst.Furthermore, supported silver salts can be used as stoichiometric oxidizing agents for aniline oxidation to azo compounds [205]. Once more, however, reports dealing with supported Cu or Ag catalysts (especially heterogeneous catalysts) for amine oxidation are scarce which is not necessarily connected to their catalytic inactivity as the rapid development for gold catalysts has shown. In fact, the activity of gold was indicated already earlier by the successful use of gold‐modified electrode materials in the electrocatalytic oxidation of amines [206‐210]. Thus, the successful use of silver nanoparticles [83] as well as copper and silver oxides [211] as amine oxidation electrocatalysts might induce further research in this field. Figure 2‐12: In situ synthesis of Au/CeO2 for amine oxidation: CeO2, Au(OAc)3 and amine solution were mixed simultaneously. Au/CeO2 formed under reaction conditions with Au particle sizes from a few nm to ca. 30 nm [197]; reprinted with permission from Elsevier © 2009 (no higher image resolution available). 2.3.7 <strong>Oxidation</strong> of hydroquinones Quinone and hydroquinone derivatives have found wide‐spread use in industrial chemistry [11] e.g. as antioxidants. Quinones can also function as relevant oxidizing agents especially as cofactors in enzymes such as amine oxidase (e.g. [212] and ref. therein) containing copper as the active metal. It is therefore not surprising that many Cu‐based catalysts are reported for the regeneration of hydroquinones to quinones for which a high number of especially homogeneous catalysts can be found in the open literature. An early extensive study evaluated various dissolved Cu‐salts as catalysts in the aerobic oxidation of hydroquinone to p‐benzoquinone [213]. As one of the first heterogeneous Cu catalysts CuSO4/Al2O3 was used with oxygen for the oxidation of various hydroquinones achieving high selectivities (Table 2‐8, entry 1) [46]. This catalyst was capable of also 50
Table 2-8: <strong>Oxidation</strong> of hydroquinones. OH O catalyst [Ox] Entry Catalyst Substrate Oxidant Solvent T (°C) Rct. time (h) Conversion Selectivity TOF (h -1 ) Ref. 1 CuSO4/Al2O3 HQ a O2 propyl acetate 100 8 94% b - 0.6 [46] 2 Cu3(BTC)2 HQ a O2 Tris-HCl-buffer 40 - - - 100 [214] 3 Cu II -chitosan HQ a H2O2 c H2O RT - - - - [215] 4 Cu-Al(O)OH HQ O2 toluene 25 2 96% b - 11 [216] 5 Cu(OH)2/SiO2 CAT d,e H2O2 aq. NaOH 22 - - - - [217] 6 Cu2O nanocubes TMHQ f O2 MeOH/H2O 50 - 75% - 1 [57] 7a Cu/Cu2O/CuO nanopowders TMHQ f O2 MeOH/H2O 50 - 59% g - - [55] 7b Cu/Cu2O/CuO nanopowders TMHQ d O2 MeOH/H2O 50 - 79% h - - [55] 8 Ag2O HQ H2O2 MeOH 25 0.5 94% 99% 14 [218] 9 Au-polymer HQ O2 CHCl3/H2O RT 3 86% b - 115 [219] a b c Hydroquinone. Yield. Reaction proceeds also with O2. d Catechol. e Reaction product: α-hydro-β-hydroxymuco-γ-lactone. f Trimethylhydroquinone. g OH O Without previous magnetization. h With previous magnetization.
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TECHNICAL UNIVERSITY OF DENMARK (DT
Page 3 and 4:
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 .......
Page 13 and 14: 5.3.5 Macroscopic mass transport in
Page 15 and 16: Chapter 1 Introduction With its gre
Page 17 and 18: 1. Introduction Scheme 1‐1: High
Page 19 and 20: 1. Introduction Figure 1‐2: Phase
Page 21 and 22: 1. Introduction [28] S. Bawaked, N.
Page 23 and 24: 2.1 Introduction 2.1 Introduction E
Page 25 and 26: 2.2.1 Synthesis of gold catalysts 2
Page 27 and 28: 2.2 Catalyst synthesis for oxidatio
Page 29 and 30: 2.2 Catalyst synthesis for oxidatio
Page 31 and 32: 2.3 Selective liquid‐phase oxidat
Page 33 and 34: Table 2-1: Overview over alcohol ox
Page 45 and 46: Ph O O Ph (4) (5) 2.3 Selective liq
Page 51 and 52: Table 2-4: Side-chain oxidation of
Page 53 and 54: 2.3.4 Oxidation of cyclohexane 2.3
Page 55 and 56: Table 2-5: Oxidatin of cyclohexane.
Page 59 and 60: Table 2-6: Ring hydroxylation of ar
Page 63: Table 2-7: Aerobic oxidation of ami
Page 69 and 70: Table 2-9: Oxidation of silanes wit
Page 71 and 72: Table 2-10: Oxidation reactions cat
Page 73 and 74: 2.4 Strengths and opportunities of
Page 81 and 82: 2.6 References 2.6 References [1] M
Page 83 and 84: 2.6 References [56] H. Tumma, N. Na
Page 85 and 86: 2.6 References [113] C. Keresszegi,
Page 87 and 88: 2.6 References [169] Q. Zhu, Y. Lia
Page 89 and 90: 2.6 References [223] M. Fetizon, M.
Page 91 and 92: Chapter 3 Selective Liquid-Phase Ox
Page 93 and 94: 3.2 Experimental 3.2.1 Catalyst pre
Page 95 and 96: 3.3 Results Scattering amplitudes a
Page 97 and 98: Absorption (a.u.) 1.2 1.0 0.8 0.6 0
Page 99 and 100: Conversion (%) 100 90 80 70 60 50 4
Page 101 and 102: 3.3 Results Figure 3‐5: In situ X
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
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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,
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4.3 Results Scheme 4‐1: Oxidation
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4.3 Results Figure 4‐2: Formation
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4.3 Results oxidation by either 2,6
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Absorption (a.u.) Absorption (a.u.)
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4.3 Results atomic mixing of Ag and
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4.3 Results Figure 4‐7: Influence
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4.4 Discussion and mechanistic cons
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4.5 Conclusions heterogeneous radic
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4.6 References [29] S.I. Zabinsky,
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Chapter 5 Experimental Determinatio
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5.2 Experimental The most important
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5.2 Experimental Eurotherm 2216e te
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Figure 5-1: Schematic view of the e
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(Eq. 5‐5) AB i j ε AB i j β 5.2
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(a) (b) (c) (d) (e) (f) (g) (h) (i)
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5.3 Results two association sites o
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Pressure (bar) 150 145 140 135 5.3
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5.3 Results Figure 5‐7: Oxidation
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Weight (g) 5.3 Results Figure 5‐8
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5.4 Discussion catalytic reactions
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5.4 Discussion corresponding CO2‐
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5.5 Conclusions 5.5 Conclusions The
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5.6 References [29] I. Tsivintzelis
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6.1 Introduction 6.1 Introduction A
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6.2 Experimental [38]. In a typical
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6.3 Results out in 1 mm quartz tube
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6.3 Results Figure 6‐2: Structure
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6.3 Results Figure 6‐4: Epoxidati
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6.3 Results Figure 6‐6: Compariso
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6.3 Results Figure 6‐8: Influence
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6.3 Results investigated the epoxid
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6.3 Results Figure 6‐10: Co‐epo
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6.3 Results Figure 6‐11: EXAFS an
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6.4 Discussion would need to be for
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6.5 Conclusions Formation of the ep
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6.6 References [28] J. Perles, N. S
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Chapter 7 Concluding Remarks 7.1 Co
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7.2 Final remarks and outlook speci
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Acknowledgements Acknowledgements T
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Curriculum Vitae Matthias Josef Bei
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