Propylene Epoxidation via Shell's SMPO Process

Buijink, Jan-Karel F.; Lange, Jean‐Paul; Bos, A.N.R.; Horton, Andrew D.; Niele, F.G.M.

doi:10.1016/b978-0-444-53188-9.00013-4

Cited by 24 publications

(12 citation statements)

References 25 publications

(21 reference statements)

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“…On the basis of this consideration we decided to perform the oxidation of cumene without aldehyde initiator. In classical protocols, the autoxidation of CU and other hydrocarbons is conducted at temperatures higher than 110°C, both to overcome the thermodynamic barrier of reactivity between oxygen and the alkyl aromatic, and to promote initiation of new radical chains by partial decomposition of the hydroperoxide products. Both these aspects positively influence the kinetic of the process, but negatively affect its selectivity.…”

Section: Resultsmentioning

confidence: 99%

Is it possible to implement N‐hydroxyphthalimide homogeneous catalysis for industrial applications? A case study of cumene aerobic oxidation

Melone

Prosperini

Ercole

et al. 2013

J of Chemical Tech & Biotech

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BACKGROUND\ud In spite of its efficiency and versatility, examples of the use of N-hydroxyphthalimide (NHPI) as catalyst for oxidations at industrial scale are scant, mainly due to the lack of methodologies for the recovery and reuse of the catalyst. This paper reports a step by step investigation of the aerobic oxidation of cumene (CU), in order to verify the usability of NHPI catalysis in industrial processes.\ud \ud RESULTS\ud CU is oxidized to the corresponding cumyl hydroperoxide (CHP) at 70°C in the presence of a polar co-solvent and 1% of NHPI with good conversion (>30%) and almost complete selectivity (>90%), without requiring the use of additional initiators. The catalyst is recovered at the end of the oxidation process by removal of polar co-solvent, with consequent precipitation of NHPI. The resulting filtered mixture is treated with non-basic supports, which are capable of adsorbing the residual NHPI by physical interaction. Finally, the adsorbing solids can be regenerated by washing with a polar solvent, allowing the recovery of residual catalyst.\ud \ud CONCLUSION\ud We provide evidence for the feasibility of the use of NHPI catalysis for industrial applications by investigating the case study of CU oxidation. The process can be performed under mild conditions without requiring the use of sacrificial initiators. The effect of temperature and composition in the NHPI precipitation step is investigated. The performances of basic and non-basic adsorbing beds during the recovery of residual NHPI are compared. The results obtained indicate that the recovery and recycling of the unaltered catalyst is possible without affecting, at the same time, the nature of cumyl hydroperoxide

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Section: Resultsmentioning

confidence: 99%

Is it possible to implement N‐hydroxyphthalimide homogeneous catalysis for industrial applications? A case study of cumene aerobic oxidation

Melone

Prosperini

Ercole

et al. 2013

J of Chemical Tech & Biotech

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“…Indeed, mobility of Ti IV centers grafted on silicates has been previously observed, 100 and has been invoked as a contributing factor to long-term deactivation of industrial catalysts. 101 4.5. Mechanistic Implications: Confinement within 12-MR Pockets Lowers Entropic Barriers for Reactant Activation.…”

Section: Location Of Grafted Cti Centers Within Specific Support Envi...mentioning

confidence: 99%

Dynamic Reorganization and Confinement of Ti^IV Active Sites Controls Olefin Epoxidation Catalysis on Two-Dimensional Zeotypes

et al. 2019

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The effect of dynamic reorganization and confinement of isolated TiIV catalytic centers supported on silicates is investigated for olefin epoxidation. Active sites consist of grafted single-site calix[4]arene–TiIV centers or their calcined counterparts. Their location is synthetically controlled to be either unconfined at terminal T-atom positions (denoted as type-(i)) or within confining 12-MR pockets (denoted as type-(ii); diameter ∼7 Å, volume ∼185 Å3) composed of hemispherical cavities on the external surface of zeotypes with *-SVY topology. Electronic structure calculations (density functional theory) indicate that active sites consist of cooperative assemblies of TiIV centers and silanols. When active sites are located at unconfined type-(i) environments, the rate constants for cyclohexene epoxidation (323 K, 0.05 mM TiIV, 160 mM cyclohexene, 24 mM tert-butyl hydroperoxide) are 9 ± 2 M–2 s–1; whereas within confining type-(ii) 12-MR pockets, there is a ∼5-fold enhancement to 48 ± 8 M–2 s–1. When a mixture of both environments is initially present in the catalyst resting state, the rate constants reflect confining environments exclusively (40 ± 11 M–2 s–1), indicating that dynamic reorganization processes lead to the preferential location of active sites within 12-MR pockets. While activation enthalpies are ΔH ‡ app = 43 ± 1 kJ mol–1 irrespective of active site location, confining environments exhibit diminished entropic barriers (ΔS ‡ app = −68 J mol–1 K–1 for unconfined type-(i) vs −56 J mol–1 K–1 for confining type-(ii)), indicating that confinement leads to more facile association of reactants at active sites to form transition state structures (volume ∼ 225 Å3). These results open new opportunities for controlling reactivity on surfaces through partial confinement on shallow external-surface pockets, which are accessible to molecules that are too bulky to benefit from traditional confinement within micropores.

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“…A few years after the MTBE/PO process, a new cooxidation process took over the technological lead, the so-called SM/PO process [34], which is summarized in Equation (21). Two main factors contributed to the success of the SM/PO process, of which several variations exist using homogeneous Mo VI or heterogeneous Ti-on-silica catalysts: first of all, the good selectivity in the oxidation of ethylbenzene with O 2 to the corresponding hydroperoxide, and second the large available market for the coupled product styrene.…”

Section: ð20þmentioning

confidence: 99%

Oxidation

Teles

Hermans

Franz³

et al. 2015

Ullmann's Encyclopedia of Industrial Chemistry

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The article contains sections titled: 1. Introduction 2. Overview of industrial oxidation processes 2.1. Inorganic chemicals 2.1.1. Sulfur derivatives 2.1.2. Carbon derivatives 2.1.3. Nitrogen derivatives 2.1.4. Chlorine derivatives 2.2. Organic chemicals 2.2.1. Olefins and alkynes 2.2.2. Epoxides 2.2.3. Hydroperoxides 2.2.4. Alcohols 2.2.5. Aldehydes 2.2.6. Ketones 2.2.7. Phenols and derivatives 2.2.8. Carboxylic acids, saturated 2.2.9. Carboxylic acids and anhydrides, unsaturated 2.2.10. Carboxylic acids and anhydrides, aromatic 2.2.11. Esters, lactones and carbonates 2.2.12. Nitriles 2.2.13. Oxidized nitrogen compounds 2.2.14. Chlorinated compounds 2.2.15. Sulfur compounds 3. Thermodynamics; Stability of Hydrocarbons 4. Reaction Types 5. Homolytic Oxidation 5.1. Historical Development; Reaction Mechanism; Radical Reactivity 5.2. Kinetics of Autoxidation 5.3. Differences between Liquid‐ and Gas‐Phase Autoxidations 5.4. Homolytic Oxidation in the Liquid Phase 5.4.1. Secondary Reactions of Radicals, Peroxides, and other Intermediates 5.4.2. Metal Catalysis in Homolytic Liquid‐Phase Oxidation 5.4.3. Inhibitors of Homolytic Liquid‐Phase Oxidation 5.4.4. Special Cases of Homolytic Oxidation 5.4.5. Process Technology of Homolytic Liquid‐Phase Oxidation 5.5. Homolytic Gas‐Phase Oxidation 5.6. Gas Explosions and Safety Data 6. Heterolytic Oxidation 6.1. Heterolytic Oxidation in the Liquid Phase 6.2. Heterogeneously Catalyzed Gas‐Phase Oxidation 6.2.1. Oxidation Catalysts 6.2.2. Process Technology of Heterogeneously Catalyzed Oxidations

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Propylene Epoxidation via Shell's SMPO Process

Cited by 24 publications

References 25 publications

Is it possible to implement N‐hydroxyphthalimide homogeneous catalysis for industrial applications? A case study of cumene aerobic oxidation

Is it possible to implement N‐hydroxyphthalimide homogeneous catalysis for industrial applications? A case study of cumene aerobic oxidation

Dynamic Reorganization and Confinement of Ti^IV Active Sites Controls Olefin Epoxidation Catalysis on Two-Dimensional Zeotypes

Oxidation

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Propylene Epoxidation via Shell's SMPO Process

Cited by 24 publications

References 25 publications

Is it possible to implement N‐hydroxyphthalimide homogeneous catalysis for industrial applications? A case study of cumene aerobic oxidation

Is it possible to implement N‐hydroxyphthalimide homogeneous catalysis for industrial applications? A case study of cumene aerobic oxidation

Dynamic Reorganization and Confinement of TiIV Active Sites Controls Olefin Epoxidation Catalysis on Two-Dimensional Zeotypes

Oxidation

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Dynamic Reorganization and Confinement of Ti^IV Active Sites Controls Olefin Epoxidation Catalysis on Two-Dimensional Zeotypes