SPRINGER BRIEFS IN MOLECULAR SCIENCE GREEN CHEMISTRY FOR SUSTAINABILITY Peng Wu · Hao Xu Le Xu · Yueming Liu Mingyuan He MWW-Type Titanosilicate Synthesis, Structural Modification and Catalytic Applications to Green Oxidations SpringerBriefs in Molecular Science Green Chemistry for Sustainability Series Editor Sanjay K. Sharma For furthervolumes: http://www.springer.com/series/10045 Peng Wu Hao Xu Le Xu • • Yueming Liu Mingyuan He • MWW-Type Titanosilicate Synthesis, Structural Modification and Catalytic Applications to Green Oxidations 123 PengWu HaoXu Le Xu YuemingLiu MingyuanHe ShanghaiKey Laboratoryof Green Chemistry and Chemical Processes Department of Chemistry EastChina Normal University Shanghai China ISSN 2212-9898 ISBN 978-3-642-39114-9 ISBN 978-3-642-39115-6 (eBook) DOI 10.1007/978-3-642-39115-6 SpringerHeidelbergNewYorkDordrechtLondon LibraryofCongressControlNumber:2013945287 (cid:2)TheAuthor(s)2013 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpartof the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation,broadcasting,reproductiononmicrofilmsorinanyotherphysicalway,andtransmissionor informationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodology now known or hereafter developed. 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While the advice and information in this book are believed to be true and accurate at the date of publication,neithertheauthorsnortheeditorsnorthepublishercanacceptanylegalresponsibilityfor anyerrorsoromissionsthatmaybemade.Thepublishermakesnowarranty,expressorimplied,with respecttothematerialcontainedherein. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Preface The discovery of titanosilicates opens up new possibilities of developing hetero- geneous catalytic processes for selective oxidation reactions, which has made a breakthrough in the area of zeolite materials and catalysis. Although the first generation of titanosilicate TS-1 dates back to almost 30 years ago, the research activities are still being continued worldwide in design and synthesis of novel titanosilicates, insight into active sites as well as developing practically useful catalytic technologies. In this sense, a series of titanosilicates differing in crys- tallinestructureandporedimensionhavebeensynthesizedsuccessfully.Particular efforts have been devoted to searching for the oxidation catalysts which have larger pore dimensions useful to process bulky molecules. Derived from lamellar precursors, so-called layered zeolites are constructing an important family in zeolite materials. Different from those with three-dimensional crystalline struc- tures already formed in hydrothermal synthesis, the layered zeolites possess structural diversity and their structures are mendable by post modification. Focusing on recent research advances in a new generation of titanosilicate Ti-MWW that comes from a lamellar precursor, this monograph consists offive chapters. Chapter 1 introduces briefly the catalytic features and research progress of titanosilicate catalysts. Chapter 2 describes the methods for the preparation of Ti-MWW, including hydrothermal synthesis and post isomorphous substitution route either in the presence or absence of boric acid. Chapter 3 figures out the structural modifications of Ti-MWW, full or partial delamination, and interlayer poreexpansionby,silylationorpillaringtechniques.Chapter4dealswithpotential catalyticapplicationsofthusdevelopedcatalyststoinnovativeselectiveoxidations includingepoxidationofvariousalkenesandammoximation ofketones tooxime. Chapter 5 gives the prospects for the development and application of Ti-MWW zeolite in future. The contents range from fundamental knowledge to practically usable techniques that have been established on this specific titanosilicate. It is our great pleasure working in this research area with many excellent experts and students from both China and Japan. We would like to sincerely thank professors Takashi Tatsumi, Tatsuaki Yashima and Takayuki Komatsu v vi Preface (Tokyo Institute of Technology, Japan), Osamu Terasaki (Stockholm University, Sweden) and Dr. Weibin Fan (Chinese Academy of Science, China) for their fruitful collaboration. Many students from East China Normal University, China and Yokohama National University, Japan have made great contributions to this research subject. Without their hard work and effort, it would have been impos- sible to put the independent topics together. Shanghai, China Peng Wu Hao Xu Le Xu Yueming Liu Mingyuan He Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2 Synthesis of Ti-MWW Zeolite. . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.2 Boron-Containing Ti-MWW Synthesis. . . . . . . . . . . . . . . . . . . 12 2.3 Boron-Less Ti-MWW Synthesis . . . . . . . . . . . . . . . . . . . . . . . 18 2.3.1 Synthesis of Ti-MWW Using Linear-Type Quaternary Alkylammonium Hydroxides. . . . . . . . . . . . 18 2.3.2 Synthesis of Ti-MWW by a Dry-Gel Conversion Method. . . . . . . . . . . . . . . . . . . . . . . . . . . 19 2.3.3 Synthesis of Ti-MWW with the Assistant of F- Ions . . . 23 2.4 Boron-Free Ti-MWW Synthesis . . . . . . . . . . . . . . . . . . . . . . . 26 2.4.1 Synthesis of Ti-MWW with Dual Structure-Directing Agents. . . . . . . . . . . . . . . . . . . . . . 26 2.4.2 Synthesis of B-Free Ti-MWW Through Reversible Structure Conversion. . . . . . . . . . . . . . . . . . . . . . . . . . 30 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3 Structural Modification of Ti-MWW: A Door to Diversity. . . . . . . 35 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 3.2 Structural Conversion to Enhance the Hydrophobicity . . . . . . . . 37 3.3 Swelling and Full Delamination of Ti-MWW. . . . . . . . . . . . . . 41 3.4 Partial Delamination of Ti-MWW. . . . . . . . . . . . . . . . . . . . . . 44 3.5 Pillaring of Ti-MWW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.5.1 Interlayer Silylation of Ti-MWW . . . . . . . . . . . . . . . . . 52 3.5.2 Synthesis of Ti Containing Interlayer Expanded MWW Structure Via a Combination of Silylation and Ti Insertion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 vii viii Contents 4 Catalytic Properties of Ti-MWW in Selective Oxidation Reactions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 4.2 Epoxidation of Alkenes over Ti-MWW . . . . . . . . . . . . . . . . . . 64 4.2.1 Epoxidation of Propylene over Ti-MWW. . . . . . . . . . . . 65 4.2.2 Unique Trans-Selectivity of Ti-MWW in Epoxidation of Cis/Trans-Alkenes with Hydrogen Peroxide. . . . . . . . 68 4.2.3 Selective Liquid-Phase Oxidation of Cyclopentene Over Ti-MWW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 4.2.4 Highly Efficient and Selective Production of Glycidol Through Epoxidation of Allyl Alcohol with H O . . . . . . 74 2 2 4.2.5 Selective Epoxidation of Diallyl Ether with H O . . . . . . 78 2 2 4.2.6 Epoxidation of 2,5-Dihydrofuran to 3,4-Epoxytetrahydrofuran. . . . . . . . . . . . . . . . . . . . . 82 4.2.7 Selective Production of Epichlorohydrin Through Epoxidation of Allyl Chloride . . . . . . . . . . . . . . . . . . . 85 4.3 Ammoximation of Ketones and Aldehydes. . . . . . . . . . . . . . . . 88 4.3.1 Ammoximation of Methyl Ethyl Ketone . . . . . . . . . . . . 88 4.3.2 Ammoximation of Cyclohexanone . . . . . . . . . . . . . . . . 92 4.3.3 Ammoximation of Cyclohexanone in a Continuous Slurry Reactor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 4.3.4 Cyclohexanone Ammoximation with Core-Shell Structured Ti-MWW@meso-SiO . . . . . . . . . . . . . . . . . 99 2 4.4 Unique Catalytic Properties of Fluorine-Planted Ti-MWW. . . . . 103 4.5 Oxidation of Amines, 1,4-Dioxane, Sulfides and Olefinic Alcohols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106 4.5.1 Oxidation of Pyridines. . . . . . . . . . . . . . . . . . . . . . . . . 106 4.5.2 Oxidation of 1,4-Dioxane. . . . . . . . . . . . . . . . . . . . . . . 109 4.5.3 Oxidative Desulfurization with Ti-MWW . . . . . . . . . . . 111 4.5.4 Epoxidation and Cyclization of Olefinic Alcohols. . . . . . 112 4.6 Selective Epoxidation of Propylene to PO with H 2 and O Over Bifunctional Au/Ti-MWW Catalyst . . . . . . . . . . . 114 2 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119 5 Conclusions and Prospects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125 Chapter 1 Introduction Zeolites are a class of crystalline aluminosilicates and silicalites with the silicon and aluminum cations tetrahedrally linked by the oxygen bridges in the frame- work, and then three-dimensional (3D) networks are constructed to form the channels, pores, cages, and cavities [1]. Zeolites thus possess well-defined crys- tallinestructuresaswellasthetexturalpropertiesofhighspecificsurfaceareaand high adsorption capacity. The pore windows and channels of zeolites are closely related to their well-defined crystalline structures, and usually their sizes are of molecular dimensions in the micropore region [2]. This kind of unique porosity endowszeoliteswithmoleculesievingabilitiesfordiscriminatingguestmolecules and separating reactants/products. Even strong electric fields are possibly gener- atedwithinzeolitepores,andasheterogeneouscatalysts,zeolitesthenmayexhibit strong quantum effects in combination with the molecular confinement of micropores [3, 4]. The chemical compositions of the zeolite frameworks are changeable and amendable, not only in the silicon to metal ratios but also in the types of coor- dinated metal ions. TheSi/Al ratio could bevaried in the range of one toinfinite, whereas the transition metals and the elements other than Si and Al are also incorporated into the zeolite framework via isomorphous substitution, e.g., P [5], B[6],Ga[7],Fe[8],Ti[9],Sn[10],Ge[11],Zr[12],andV[13],etc.,givingrise to so-called metallosilicates. This widens significantly the application range of zeolites as multifunctional catalysts. Zeolites in aluminosilicate forms have long been used as solid–acid catalysts in petrochemical industry. For example, Faujasite Y (with a structure code of FAU,recognizedbyInternationalZeoliteAssociation,IZA)iswidelyusedasfluid catalytic cracking (FCC) catalyst, replacing conventional amorphous silica- aluminacatalysts[14–16].Thisopenedthedoorforperhapsthebiggestrevolution inoilrefiningindustry.Thereafter,thewell-knownpentasilaluminosilicateZSM-5 with the MFI topology [17], developed in 1970s by Mobil (now known as ExxonMobil),isaversatileshape-selectivecatalystinpetrochemicalprocessesfor producing high valuable aromatics, e.g., para-xylene [18]. In 1983, Taramasso et al. [19] from Enichem group envisaged the first titanosilicate with the Ti cations isomorphously substituted in the MFI-type P.Wuetal.,MWW-TypeTitanosilicate, 1 SpringerBriefsinGreenChemistryforSustainability, DOI:10.1007/978-3-642-39115-6_1,(cid:2)TheAuthor(s)2013 2 1 Introduction Fig.1.1 Liquid-phase oxidationreactionsbasedon TS-1/H O system 2 2 silicalite-1, which is well known as TS-1. Combining the hydrophobic feature in aqueous solution and the unique porosity of the MFI framework, those isolated tetrahedral Ti sites in TS-1 can activate hydrogen peroxide molecules under rel- atively mild conditions (generally\373 K and 1 atm), and as shown in Fig. 1.1, they are capable of catalyzing the selective oxidation reactions of a variety of substrates [20, 21]. These reactions give water as the sole byproduct. Two world- scale processes, cyclohexanone ammoximation [22] and propylene epoxidation [23], have now been commercialized based on the TS-1/H O catalytic system. 2 2 Theseprocessesareenvironmentallybenignintermsofgreennessandzerowaste disposal.Expandingthecatalyticapplicationsofzeolitesfromsolid–acidcatalysis to redox field, the great success of TS-1 is considered as the third milestone in zeolite catalysis after Y and ZSM-5 zeolites. The discovery of TS-1 has encouraged the researchers to develop other tita- nosilicates with different zeolite structures [24–49], especially those with larger porosities and high cost performance, because TS-1 encounters some shortcom- ings. TS-1 is less active to the bulky and cyclic molecules owing to diffusion hindranceimposedbyitsmediumporesof10-memberedring(MR).TS-1always prefersaproticsolventlikemethanol,whichcausesthesolvolysisoftheepoxides inalkeneepoxidation,loweringtheselectivitytodesirableproducts[50].Fromthe viewpoint of industrial applications, TS-1 still suffers a high cost of catalyst manufacturing because it requires the use of expensive tetrapropylammonium hydroxide (TPAOH) as structure-directing agent (SDA) and organic silica source of tetraethylorthosilicate (TEOS). To be active enough, the hydrothermally