Polymer attached cobalt-phthalocyanines as catalysts in the autoxidation of thiols Citation for published version (APA): Schutten, J. H. (1981). Polymer attached cobalt-phthalocyanines as catalysts in the autoxidation of thiols. Technische Hogeschool Eindhoven. https://doi.org/10.6100/IR119903 DOI: 10.6100/IR119903 Document status and date: Published: 01/01/1981 Document Version: Publisher’s PDF, also known as Version of Record (includes final page, issue and volume numbers) Please check the document version of this publication: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. 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If the publication is distributed under the terms of Article 25fa of the Dutch Copyright Act, indicated by the “Taverne” license above, please follow below link for the End User Agreement: www.tue.nl/taverne Take down policy If you believe that this document breaches copyright please contact us at: [email protected] providing details and we will investigate your claim. Download date: 27. Sep. 2021 POLYMER ATTACHED COBALT -PHTHALOCYANINES AS CATALYSTS IN THE AUTOXIDATION OF THIOLS J. H. SCHUTTEN POLYMER ATTACHED COBALT-PHTHALOCYANINES AS CATALYSTS IN THE AUTOXIDATION OF THIOLS POLYMER ATTACHED COBALT -PHTHALOCYANINES AS CATALYSTS IN THE AUTOXIDATION OF THIOLS PROEFSCHRIFT TER VERKRIJGING VAN DE GRAAD VAN DOCTOR IN DE TECHNISCHE WETENSCHAPPEN AAN DE TECHNISCHE HOGESCHOOL EINDHOVEN, OP GEZAG VAN DE RECTOR MAGNIFICUS, PROF. IR. J. ERKELENS, VOOR EEN COMMISSIE AANGEWEZEN DOOR HET COLLEGE VAN DEKANEN IN HET OPENBAAR TE VERDEDIGEN OP VRIJDAG 30 JANUARI1981 TE 16.00 UUR DOOR JAN HENDRIK SCHUTTEN GEBOREN TE EIBERGEN ORUK W1BRO HEt.MOND DIT PROEFSCHRIFT IS GOEDGEKEURD DOOR DE PROMOTOREN: Prof. dr. R. Prins en Prof. dr. ir. A.L. German Aan Lidy Aan Titia CONTENTS 1 INTRODUCTION 1 1.1 Multifunctional catalysts and the application of polymers in catalysis 1 1.2 Catalytic oxidation of thiols; merox sweetening 4 1.3 Aim and outline of this thesis 6 References 8 2 AUTOXIDATION OF THIOLS PROMOTED BY A BIFUNCTIONAL CATALYST PREPARED BY POLYMER ATTACHMENT OF A COBALT­ PHTHALOCYANINE 11 2.1 Introduction 11 2.2 Experimental 12 2.3 Results 17 2.3.1 Characterization of the catalysts 17 2.3.2 Catalytic activity measurements 21 2.4 Discussion 24 References 28 3 THE ROLE OF HYDROGEN PEROXIDE DURING THE AUTOXIDATION OF THIOLS PROMOTED BY BIFUNCTIONAL POLYMER-BONDED COBALT­ PHTHALOCYANINE CATALYSTS 30 3.1 Introduction 30 3.2 Experimental 32 3.3 Results and discussion 33 3.3.1 The concentration of H2o2 during the catalyzed oxidation of thiol 33 3.3.2 Production of H2o2 35 3.3.3 Conversion of H2o2 35 3.3.4 Deactivation of the catalysts 41 3.4 Conclusions 46 References 47 4 CATALYSIS OF THE DECOMPOSITION OF HYDROGEN PEROXIDE 50 4.1 Introduction and literature survey 50 4.2 Experimental 56 4.3 Results and discussion 58 4.3.1 Metallic oxides 58 4.3.2 Metal complexes 61 4.3.3 Activated carbon 64 4.4 Conclusions 67 References 69 5 SALT AND MEDIUM EFFECTS ON THE CATALYTIC OXIDATION OF THIOLS 72 5.1 Introduction 72 5.2 Results 73 5.2.1 Activities of the polymeric catalysts in toluene 73 5.2.2 Activities of the catalysts in the presence of alcohols 74 5.2.3 The influence of the addition of salt on the catalytic activity 78 5.3 Discussion 81 5.3.1 Polymeric catalysts in toluene 81 5.3.2 Catalytic activity in water/ alcohol mixtures 82 5.3.3 Catalytic activity in the presence of salts 85 References 88 6 COBALTPHTHALOCYANINE/POLY(VINYLAMINE) COMPLEXES AS BIFUNCTIONAL CATALYSTS IN THE AUTOXIDATION OF THIOLS. EFFECT OF THE DISTRIBUTION OF COBALT SITES OVER THE POLYMERIC COILS 90 6.1 Introduction 90 6.2 Experimental 92 6.3 Results 93 6.3.1 Visible light spectral measurements 93 6.3.2 Catalytic activity measurements 96 6.4 Discussion 98 References 103 7 MACROPOROUS STYRENE-DIVINYLBENZENE COPOLYMERS AS CARRIERS FOR POLY(VINYLAMINE)/ COBALTPHTHALOCYANINE OXIDATION CATALYSTS 105 7.1 Introduction 105 7.2 Experimental 107 7.3 Results and discussion 110 7. 3.1 Macroporous styrene-divinyl.­ benzene copolymers 110 7.3.2 Grafting of poly(N-vinyl-tert­ butylcarbamate) onto macro­ porous styrene-divinylbenzene copolymers 116 7.3.3 Preparation of grafted poly­ (vinylamine) from grafted poly­ (N-vinyl-tert-butylcarbamate) 120 7.3.4 Catalytic activities of the heterogeneous bifunctional catalysts 122 References 125 8 FINAL REMARKS 127 References 129 SUMMARY 131 SAMENVATTING 135 CURRICULUM VITAE 139 DANKBETUIGING 140 INTRODUCTION 1.1 Multifunctional catalysts and the application of polymers in catalysis In recent years an increasing effort has been devoted to the design of multifunctional catalysts. Apparently, this interest has been stimulated by the fact that multi­ functionality is one of the most important characteristics of enzymes, the catalysts in biological systems. Synthetic model systems are investigated to elucidate the factors governing the efficient cooperation between different catalytic groups in enzymatic catalysis. Polymers may be advantageously applied for the development of model systems for enzymes and of new multifunctional catalysts for com­ plex reactions. The physical and chemical properties of polymers may be varied to a large extent and, therefore, tailormade polymers may be designed to hold a desired combination of catalytic sites. This thesis deals with an investigation on multi­ functional polymeric catalysts for the autoxidation of thiols. It is well established, that an efficient catalyst for this autoxidation should possess oxidation sites and basic sites in cooperative interaction. Such a bifunctional catalytic system can be obtained by attachment of an oxi­ dation catalyst {in our case a cobaltphthalocyanine) to a polymer with incorporated basic groups (see [1]). Thedevelopmentof specifically functionalized poly­ mers recieves currently the attention of chemists in a variety of fields [2-11]. Biologically active molecules, such as drugs [11], hormones [12] and enzymes [4, 6, 7] have been attached to polymers for a number of uses. Functionalized resins have found applications, for example as insolubilized chelating resins [10, 13], supports for 1 (a) (b) (c) (d) Fig. 1. Various applications of polymers in catalysis (a) solid polymeric support, (b) weakly crosslinked polymer, (c) non-crosslinked polymer, and (d) non­ crosslinked polymer fixed on a solid support (• =catalytic site). organic syntheses [2, 8], ion exchangers [14] and as beads for various chromatography purposes [5, 6, 9, 14]. Solid highly crosslinked polymers may also act as carriers of catalytically active species (see Fig. la). Several in­ vestigations have indicated that just as in case of catalysts supported on inorganic oxides the behaviour of the cata­ lytically active sites is often influenced by the polymeric support [3, 4]. Swellable weakly crosslinked polymers have also been applied as carriers for catalytically active species (Fig. lb). This approach is characterized by the possibility for large diffusional limitations of the reaction rate and the small influence of the macromolecule on the rate due to limited chain mobility [15]. More interesting from a mechanistic point of view is the application of soluble (non-crosslinked) polymers in catalysis [16, 17) (Fig. le). Several soluble (co)poly­ mers have shown remarkable high activities due to specific effects of the macromolecular chain itself. Overberger and his coworkers, who investigated the hydrolytic activity of vinyl (co)polymers containing imidazole have been responsi­ ble for a large number of contributions in this field [17, 18]. It is often claimed that the study of this type of polymeric catalysts offers the opportunity for better understanding of the unique role of enzymes [4, 16, 17]. 2 However, it must be stressed that enzymes always seem to have a single active site per subunit, whereas in contrast the synthetic polymers often possess very large numbers of active sites per chain. Furthermore, the models mostly have statistically defined active sites, while the enzyme active site is accurately defined by nature. Particularly interesting is the homogeneous catalysis by metal ions and metal complexes which are attached to macromolecules [16]. In this case the polymer does not serve solely as an inert carrier but the polymer chain influences the behaviour of the catalytic sites. Owing to the ligand being macromolecular, the local volume in the vicinity of the metal species may possess physical-chemical properties differing from the solvent. The study of the catalytic behaviour of polymer/metal complexes is therefore of interest for developing new types of catalysts, and further­ more it may give the opportunity for elucidating the role of metal ions in the active centres of metallo-proteins. For example, heme (Fe-protoporphyrin IX) modified with short peptide chains and coupled to poly(oxoethylene) was proven to be a fairly acceptable model system for the naturally occuring oxygen carriers myoglobin and hemoglobin [19].