DOCSLIB.ORG

A Microfluidic System for the Continuous Recycling of Unmodified Homogeneous Palladium Catalysts Through Liquid/Liquid Phase Separation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
A Microfluidic System for the Continuous Recycling of Unmodified Homogeneous Palladium Catalysts Through Liquid/Liquid Phase Separation A Microfluidic System for the Continuous Recycling of Unmodified Homogeneous Palladium Catalysts through Liquid/Liquid Phase Separation The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Li, Pengfei, Jason S. Moore , and Klavs F. Jensen. “A Microfluidic System for the Continuous Recycling of Unmodified Homogeneous Palladium Catalysts through Liquid/Liquid Phase Separation.” ChemCatChem 5, no. 7 (May 16, 2013): 1729–1733. As Published http://dx.doi.org/10.1002/cctc.201300054 Publisher Wiley Blackwell Version Author's final manuscript Citable link http://hdl.handle.net/1721.1/92778 Terms of Use Creative Commons Attribution-Noncommercial-Share Alike Detailed Terms http://creativecommons.org/licenses/by-nc-sa/4.0/ Continuous Recycling DOI: A Microfluidic System for Continuous Recycling of Unmodified Homogeneous Palladium Catalysts via Liquid-Liquid Phase Separation** Pengfei Li,* Jason S. Moore, Klavs F. Jensen* With their highly tunable nature and the resulting high activity and and received considerable attention.[16,17] Ryu and coworkers selectivity in promoting transformations, homogeneous catalysts reported a continuous-flow process for recycling of an ionic liquid- have dramatically shaped modern organic chemistry.[1] Industrial supported palladium catalyst in Mizoroki-Heck reaction.[12a] The applications are limited, however, by the difficulties associated with ligand and the ionic liquid used in this reaction shared the same catalyst recovery and recycling.[1b,c] As a result, many strategies structural framework. Theberge and Huck designed an have been devised to overcome those challenges,[2] including aqueous/fluorous biphasic microflow setup and used it for immobilizing the catalysts onto solid or liquid supports by structural continuous recycling of a fluorous guanidine-ligated palladium modifications,[3-7] enlarging the catalysts for ultra- or catalyst for Suzuki-Miyaura coupling.[12b] In both examples, static nanofiltration,[8] and using controlled solubility variations.[9,10] vials were used for passive liquid-liquid phase separation of the Although leaching of catalyst has remained a general challenge, pooled multiphasic mixtures. Furthermore, a “release-trap” strategy some of these methods have proved successful. However, the using coordinative polymers has been reported for continuously approaches can fall short for demanding reactions, such as reuse of catalysts.[12c,d] However, there have been no precedents palladium-catalyzed cross-coupling reactions often involving strong about continuous recycling of unmodified palladium catalysts based bases and high temperatures[11,12] and requiring deliberately on advanced ligands.[5a,18] In this communication, we describe a designed ligands. Therefore, it would be preferable to recycle the microfluidic system for continuous catalyst recycling in palladium- unmodified (“native”) catalyst directly under the best performing catalyzed hydroxylation of aryl bromides. A highly-active bulky conditions. phosphine was used as the supporting ligand and a microfluidic There are both chemical and technical hurdles associated with device for liquid-liquid phase separation. catalyst recycling of unmodified systems. First, highly active Palladium-catalyzed selective hydroxylation of aryl halides catalysts could deactivate when out of the reaction environment using biaryl phosphine ligands, first reported by Buchwald in and/or during the recycling processes. Second, convenient and 2006,[19] is a general method to prepare various phenols from readily efficient catalyst isolation is non-trivial and sometimes impossible. available aryl halides.[20] Later, Beller developed N-aryl imidazole- Third, manual operations of sensitive catalysts must be carefully based phosphine ligands for this reaction[20b,21] and interesting implemented, and the process can be very time-consuming. cationic ligands for catalyst recycling.[11a] This represented a rare Our labs have been developing continuous microflow processes example of recycling palladium catalysts in complex coupling of palladium-catalyzed cross-coupling reactions.[13] Owing to the reactions. However, the moisture-sensitive reaction conditions and high surface-volume ratio of the liquids in microchannels, heat- and using product-saturated 1,4-dioxane as the solvent for product mass-transfer are very efficient, enabling easy and precise control of separation limited the practicality. We felt that if an immiscible process parameters.[14] Along with other merits, such as producing organic/water mixture could work for this reaction, the water- less waste, reducing footprint, and ready scale-up, continuous-flow soluble phenolate could be efficiently separated from the catalyst- reactions have been regarded as one of the key green processes[15] containing organic phase. Moreover, we have previously developed liquid-liquid biphasic systems for palladium-catalyzed reactions under continuous-flow conditions.[13] Consequently, we commenced [] Prof. Dr. P. Li Center for Organic Chemistry our study by searching for an efficient biphasic catalytic system Frontier Institute of Science and Technology using 3-bromoanisole as a model substrate. Previously, two Xi’an Jiaotong University phosphines L1 and L2 were shown effective as supporting ligands 99 Yanxiang Road, Xi’an, Shaanxi, 710054 (China) for this reaction in 1,4-dioxane, with L2 performing better in most E-mail: [email protected] cases.[19a] With these ligands, we found that in a mixture of toluene and water, the reaction also proceeded well, but only when a phase- J. S. Moore, Prof. Dr. K. F. Jensen transfer catalyst (tetrabutylammonium bromide, TBAB) was added Department of Chemical Engineering as a promoter. Further optimizations under batch conditions were Massachusetts Institute of Technology 77 Massachusetts Avenue, Cambridge, MA 02139 (USA) conducted and selected results are shown in Table 1. E-mail: [email protected] Under the otherwise same conditions (Pd2(dba)3 0.5 mol%, ligand 2 mol%, 100 oC, 120 min), the reaction was complete using J. S. Moore ligand L2, while L1 led to 60% conversion (entry 2 vs. entry 1). For Dow Chemical Company an efficient flow reaction, a faster reaction would be desirable. 2301 N. Brazosport Blvd., Freeport, TX 77541 (USA) When the reaction time was decreased to 10 minutes, however, even [] P. L., J. S. M., and K. F. J. thank the Novartis International 1 mol% Pd2(dba)3 and 4 mol% of L2 gave an incomplete conversion AG for funding. P. L. thanks Prof. Stephen L. Buchwald for (92%, entry 3). At this point, a more electron-rich ligand L3[22] was his support. tested and proved more effective. With only 0.5 mol% of Pd2(dba)3 Supporting information for this article is available on the and 2 mol% of L3, the product was quantitatively formed (entry 4). WWW under or from the author. Very recently, L3 has been successfully utilized in several challenging coupling reactions;[23] here we extend its usefulness to 1 o selective hydroxylation of aryl halides. Because Pd2(dba)3 is only soluble standard sodium tosylate were heated at 100 C for 5 slightly soluble in toluene at room temperature, which may not be minutes. After the mixture was cooled down to room temperature, suitable for studying under flow conditions, allylpalladium chloride the aqueous phase containing the phenolate was carefully removed dimer was selected as a readily soluble palladium source and proved using a syringe. The yield was based on UHPLC analysis of the similarly effective (entry 5). However, we observed that palladium aqueous phase taking sodium tosylate as the internal standard. 3- black was formed immediately after reaching full conversion, which Bromoanisole (100 mol%) and the aqueous solution (same as the was in contrast to the case of Pd2(dba)3, where no palladium black first run) were added to the reaction tube via syringes, and the was observed. Further decrease in reaction time led to incomplete resulting mixture was again heated at 100 oC for 5 minutes, followed conversion and the reaction using allylpalladium chloride dimer was by cooling down and phase separation. This procedure was repeated slightly faster than the one using Pd2(dba)3 (entry 6 and 7), and both up to a total five runs. The results in Scheme 1 did show that the reactions did not form significant amounts of palladium black. catalyst was recyclable under CIC conditions. However, the yields fluctuated significantly, apparently due to the difficulties associated Table 1. Optimizations in batch.[a] with precise control of the reaction times and temperatures and possible errors during manual operations. [Pd] x mol%, Br OMe L 2x mol% HO OMe [allylPdCl]2 0.5mol%, toluene, 2M KOH, Br OMe L3 2 mol%, toluene, HO OMe TBAB 5 mol%, 100 oC 2M KOH, TBAB 5 mol%, o Me 100 C, 5 min OMe Me Me Run Yield (%) P(t-Bu)2 MeO P(t-Bu) Me P(t-Bu) 2 i-Pr i-Pr 2 i-Pr i-Pr 1 68 i-Pr i-Pr 2 70 3 58 ArBr, [Pd], L, 4 63 biphenyl in Tol. i-Pr i-Pr i-Pr 5 55 aq. ArOK, KOH, TBAB, NaOTs L1 L2 L3 Scheme 1. Catalyst recycling in batch conditions. Entr Ligand Pd source t (min) Conversion/ y Yield (%)[b] In order to obtain reaction profiles in a flow setting, we assembled a continuous-flow setup using syringe pumps, PFA 1 L1 (2 mol%) Pd2(dba)3 120 60/58 (0.5 mol%) tubing, tee and cross junctions, and a packed-bed reactor. (see SI). Tubular reactors, filled with stainless steel spheres (60-120 m 2 L2 (2 mol%) Pd2(dba)3 120 100/95 (0.5 mol%) diameter), have been used in continuous-flow reactions to efficiently enhance biphasic mass- and heat-transfer processes.[13b,e,g] Initially, a 3 L2 (4 mol%) Pd2(dba)3 10 92/85 (1 mol%) stock solution of allylpalladium chloride dimer in 1,4-dioxane was used as one of the streams and was pumped into the reaction. We 4 L3 (2 mol%) Pd2(dba)3 10 100/98 (0.5 mol%) found that the reaction results were not reproducible, probably because the catalyst (Pd0L) formation process was not effective.
Load more

Recommended publications
  • Palladium-Catalyzed Vinylic Substitution of Aryl Halides on Polymeric Nitrogen Supports
    Louisiana State University LSU Digital Commons LSU Historical Dissertations and Theses Graduate School 1986 Palladium-Catalyzed Vinylic Substitution of Aryl Halides on Polymeric Nitrogen Supports. Chia-hsing Sun Louisiana State University and Agricultural & Mechanical College Follow this and additional works at: https://digitalcommons.lsu.edu/gradschool_disstheses Recommended Citation Sun, Chia-hsing, "Palladium-Catalyzed Vinylic Substitution of Aryl Halides on Polymeric Nitrogen Supports." (1986). LSU Historical Dissertations and Theses. 4268. https://digitalcommons.lsu.edu/gradschool_disstheses/4268 This Dissertation is brought to you for free and open access by the Graduate School at LSU Digital Commons. It has been accepted for inclusion in LSU Historical Dissertations and Theses by an authorized administrator of LSU Digital Commons. For more information, please contact [email protected]. INFORMATION TO USERS This reproduction was made from a copy of a manuscript sent to us for publication and microfilming. While the most advanced technology has been used to pho­ tograph and reproduce this manuscript, the quality of the reproduction is heavily dependent upon the quality of the material submitted. Pages in any manuscript may have indistinct print. In all cases the best available copy has been filmed. The following explanation of techniques is provided to help clarify notations which may appear on this reproduction. 1. Manuscripts may not always be complete. When it is not possible to obtain missing pages, a note appears to Indicate this. 2. When copyrighted materials are removed from the manuscript, a note ap­ pears to indicate this. 3. Oversize materials (maps, drawings, and charts) are photographed by sec­ tioning the original, beginning at the upper left hand comer and continu­ ing from left to right in equal sections with small overlaps.
    [Show full text]
  • Palladium-Catalysed Oxidation of Primary and Secondary Alcohols
    Tetrahedron 59 (2003) 5789–5816 Tetrahedron report number 645 Palladium-catalysed oxidation of primary and secondary alcohols Jacques Muzart* Unite´ Mixte de Recherche ‘Re´actions Se´lectives et Applications’, CNRS-Universite´ de Reims Champagne-Ardenne, B.P. 1039, 51687 Reims Cedex 2, France Received 23 May 2003 Contents 1. Introduction 5789 2. Oxygen as a co-oxidant 5790 2.1. Using well-determined PdII-compounds 5790 2.2. Using soluble Pd0 complexes 5795 2.3. Using stabilised palladium particles 5796 2.4. Using supported Pd0 as the starting catalyst 5797 3. Per-compounds as co-oxidants 5798 3.1. tert-Butyl hydroperoxide 5798 3.2. Hydrogen peroxide 5798 3.3. Potassium periodate 5798 4. Halogen-based co-oxidants 5799 4.1. Aromatic halides 5799 4.2. Vinylic bromides 5802 4.3. Carbon tetrachloride 5803 4.4. 1,2-Dichloroethane 5803 4.5. N-Halosuccinimides 5804 5. Metal salts as co-oxidants 5804 6. Allyl-X as hydrogen acceptors 5804 7. Double bonds as hydrogen acceptors 5805 8. Oxidations without co-oxidants or hydrogen acceptors 5808 9. Conclusions 5809 10. Note added in proof 5809 1. Introduction reactions in organic synthesis. Traditionally, stoichiometric and even over-stoichiometric amounts of metal oxides The transformation of the hydroxy group into the corre- (Eq. (1)) or metal salts (Eq. (2)) are used for such oxidations. sponding carbonyl is one of the most frequently used These procedures, which generate copious quantities of heavy metal wastes, are hardly compatible with environ- Keywords: oxidation; dehydrogenation; alcohol; palladium; catalysis. mental regulations. A number of metal-catalysed methods have been described as interesting alternatives; this has Abbreviations: ADP, allyl diethyl phosphate; Adogen, 464w, introduced a third type of reaction (Eq.
    [Show full text]
  • Pd-H from Pd/C and Triethylamine: Implications in Palladium Catalysed Reactions Involving Amines Yoann Coquerel, Paul Brémond, Jean Rodriguez
    Pd-H from Pd/C and Triethylamine: Implications in Palladium Catalysed Reactions Involving Amines Yoann Coquerel, Paul Brémond, Jean Rodriguez To cite this version: Yoann Coquerel, Paul Brémond, Jean Rodriguez. Pd-H from Pd/C and Triethylamine: Implications in Palladium Catalysed Reactions Involving Amines. Journal of Organometallic Chemistry, Elsevier, 2007, 692 (22), pp.4805-4808. 10.1016/j.jorganchem.2007.05.053. hal-00676968 HAL Id: hal-00676968 https://hal.archives-ouvertes.fr/hal-00676968 Submitted on 6 Mar 2012 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Pd-H from Pd/C and Triethylamine: Implications in Palladium Catalysed Reactions Involving Amines Yoann Coquerel,* Paul Brémond, Jean Rodriguez* Université Paul Cézanne (Aix-Marseille III), UMR CNRS 6178, Centre universitaire de St Jérôme, Service 531, 13397 Marseille Cedex 20, France. E-mail: [email protected] and jean.rodriguez@univ-cezanne .fr Tel: +33 (0) 491 28 90 88 and +33 (0) 491 28 89 33; Fax: +33 (0) 491 28 91 27 Graphical Abstract Abstract The palladium hydride-iminium complex generated from Pd/C and triethylamine catalyses the isomerisation of allylic alcohols into carbonyl compounds, and Pd/C catalyses the conjugate reduction of activated double bonds using triethylamine as the source of the two newly incorporated hydrogen atoms via the same complex.
    [Show full text]
  • Safe Handling and Disposal of Chemicals Used in the Illicit Manufacture of Drugs
    Vienna International Centre, PO Box 500, 1400 Vienna, Austria Tel.: (+43-1) 26060-0, Fax: (+43-1) 26060-5866, www.unodc.org Guidelines for the Safe handling and disposal of chemicals used in the illicit manufacture of drugs United Nations publication USD 26 Printed in Austria ISBN 978-92-1-148266-9 Sales No. E.11.XI.14 ST/NAR/36/Rev.1 V.11-83777—September*1183777* 2011—300 Guidelines for the Safe handling and disposal of chemicals used in the illlicit manufacture of drugs UNITED NATIONS New York, 2011 Symbols of United Nations documents are composed of letters combined with figures. Mention of such symbols indicates a reference to a United Nations document. ST/NAR/36/Rev.1 UNITED NATIONS PUBLICATION Sales No. E.11.XI.14 ISBN 978-92-1-148266-9 eISBN 978-92-1-055160-1 © United Nations, September 2011. All rights reserved. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. Requests for permission to reproduce this work are welcomed and should be sent to the Secretary of the Publications Board, United Nations Headquarters, New York, N.Y. 10017, U.S.A. or also see the website of the Board: https://unp.un.org/Rights.aspx. Governments and their institutions may reproduce this work without prior authoriza- tion but are requested to mention the source and inform the United Nations of such reproduction.
    [Show full text]
  • Catalytic Transfer Hydrogenation
    Catalytic Transfer Hydrogenation GOTTFRIED BRIEGER* and TERRY J. NESTRICK Department of Chemistry, Oakland University, Rochester, Michigan 48063 Received August 20, 1973 (Revised Manuscript Received November 2, 1973) Contents In 1952, Braude, Linstead, et made the sugges- tion that catalytic hydrogen transfer from an organic I. Introduction 567 donor molecule to a variety of organic acceptors might I I. Reaction Conditions 568 be possible under mild conditions. In fact, sporadic use A. Nature of the Donor 568 had been made in the past of unsaturated compounds as B. Effect of Solvents 569 hydrogen acceptors in catalytic dehydrogenation reac- C. Effect of Temperature 569 tions. However, few systematic studies were directed D. Effect of Catalyst 570 toward the reverse process, catalytic transfer hydrogena- E. Other Variables 570 tion. I I I. Applicability 570 Knowledge of the basic reaction, however, goes back A. Reduction of Multiple Bonds 570 to the turn of the century, when Knoevenage14 first ob- 1. Olefins 570 2. Acetylenes 570 served that dimethyl 1,4-dihydroterephthaIate dispropor- 3. Carbonyl Compounds 571 tionated readily in the presence of palladium black to di- 4. Nitriles 571 methyl terephthalate and (mostly cis) hexahydroterephthal- 5. Imines, Hydroxylamines, Hydrazones 571 ate. Several years later, Wieland5 observed the same 6. Azo Compounds 571 reaction with dihydronaphthalene. Wieland predicted that 7. Nitro Compounds 571 B. Hydrogenolysis 571 the reaction would also occur with the then unknown 1, Nitriles 571 dihydrobenzenes, a prediction confirmed by the work of 2. Halides 571 Zelinski and Pavlov‘ and Corson and Ipatieff‘ in the 3. Allylic and Benzylic Functional Groups 571 1930’s.
    [Show full text]
  • Platinum Metals Review
    PLATINUM METALS REVIEW A quarterly survey of research on the platinum metals and of developments in their applications in industry VOL. 9 JULY 1965 NO. 3 Contents Supported Platinum Metal Catalysts 74 Bright Palladium Plating 80 High-Stability Fixed Resistors 82 Pallador I1 83 Field Ion Microscopy of the Platinum Metals 84 Disposal of Radioactive Residues 89 Soldering Palladium Plated Electronic Components 90 Continuous Temperature Control in the Blast Furnace 91 The Wetting of Platinum and Its Alloys by Glass 92 Anodic Protection for Sulphuric Acid Tank Car 99 Abstracts I00 New Patents 107 Communications should be addressed to The Editor, Platinum Metals Revim Johnson, Matthey & Co., Limited, Hatton Garden, London, E.C.1 Supported Platinum Metal Catalysts THEIR SELECTION AND METHODS OF USE IN INDUSTRIAL PROCESSES By G. C. Bond, Pm., F.R.I.C. and E. J. Sercombe, BSC. Research Laboratories, Johnson Matthey & Co Limited A catalyst has two main functions: bond, where this is possible, is most marked (I) By its presence to enable a chemical with palladium catalysts and least with reaction to proceed much more rapidly, platinum and iridium catalysts. or under milder conditions of tempera- Rhodium, palladium and platinum readily ture and pressure, than would otherwise catalyse the hydrogenation of the acetylenic be possible. triple bond; the corresponding olefin is (2) To direct the course of a chemical formed most selectively (and most stereo- reaction into the commercially desirable specifically) over palladium, and least selec- route when two or more routes are tively over platinum. possible. The rate of hydrogenation of the benzene Of the six platinum metals-platinum, ring catalysed by any of the platinum metals palladium, rhodium, ruthenium, iridium and varies greatly with the number and nature of osmium-all except osmium show remarkable substituent groups.
    [Show full text]
  • The Palladium-Hydrogen System a SURVEY of HYDRIDE FORMATION and the EFFECTS of HYDROGEN CONTAINED WITHIN the METAL LATTICES by F
    The Palladium-Hydrogen System A SURVEY OF HYDRIDE FORMATION AND THE EFFECTS OF HYDROGEN CONTAINED WITHIN THE METAL LATTICES By F. A. Lewis ’l’he QUCCII’S Ilnibersitv of Belfast Although it can by no means be wholly 4 wry substantial amount of separated from the fields of adsorption and additional information has hen catalysis (I), and although the term “transition puhlishrd conrerning hydridm of the metal hydrides” has been applied to include platinum group metals owr thc tuo molecular complexes of transition metals which decades since the hydrides of include hydrogen in their structures (z jthe palladium and palladium alloys itere subject area of metal-hydrogen systems seems tiit. subjvct of an earlier review article most generally accepted to be concerned with in this .journal. In addition to the the effects of the subsurface incorporation of rnarw articlcs in the general literature, hydrogen within metal lattices, either in solid the subject matter has formed a solution, or in the formation of hydride phases. major part of thc. programmt’.r v,f With regard to hydrogen systems of the six swcral scientific conferencm and of a platinum metals and their companion elements, number of books and monographs iron, cobalt and nickel, in terms of such a rough appearing over this period. Further- demarcation of area of interest, studies of the more, .silvw-palladiumdiffusion tubes hydrides of palladium and its alloys have con- arc’ incorporated into hvdrogen tinued to dominate the field of investigation generators built hr Johnson 8Matthey, over the interval since an initial review article and utiiised for such diverse applica- on these systems in Platinum Meials Review (3).
    [Show full text]
  • Compounds and Catalysts
    Precious Metal Compounds and Catalysts Ag Pt Silver Platinum Os Ru Osmium Ruthenium Pd Palladium Ir Iridium INCLUDING: • Compounds and Homogeneous Catalysts • Supported & Unsupported Heterogeneous Catalysts • Fuel Cell Grade Products • FibreCat™ Anchored Homogeneous Catalysts • Precious Metal Scavenger Systems www.alfa.com Where Science Meets Service Precious Metal Compounds and Table of Contents Catalysts from Alfa Aesar When you order Johnson Matthey precious metal About Us _____________________________________________________________________________ II chemicals or catalyst products from Alfa Aesar, you Specialty & Bulk Products _____________________________________________________________ III can be assured of Johnson Matthey quality and service How to Order/General Information ____________________________________________________IV through all stages of your project. Alfa Aesar carries a full Abbreviations and Codes _____________________________________________________________ 1 Introduction to Catalysis and Catalysts ________________________________________________ 3 range of Johnson Matthey catalysts in stock in smaller catalog pack sizes and semi-bulk quantities for immediate Precious Metal Compounds and Homogeneous Catalysts ____________________________ 19 shipment. Our worldwide plants have the stock and Asymmetric Hydrogenation Ligand/Catalyst Kit __________________________________________________ 57 Advanced Coupling Kit _________________________________________________________________________ 59 manufacturing capability to
    [Show full text]
  • Precious Metal Compounds and Catalysts
    Precious Metal Compounds and Catalysts Ag Pt Silver Platinum Os Ru Osmium Ruthenium Pd Palladium Ir Iridium INCLUDING: • Compounds and Homogeneous Catalysts • Supported & Unsupported Heterogeneous Catalysts • Fuel Cell Grade Products • FibreCat™ Anchored Homogeneous Catalysts • Precious Metal Scavenger Systems www.alfa.com Where Science Meets Service Precious Metal Compounds and Table of Contents Catalysts from Alfa Aesar When you order Johnson Matthey precious metal About Us _____________________________________________________________________________ II chemicals or catalyst products from Alfa Aesar, you Specialty & Bulk Products _____________________________________________________________ III can be assured of Johnson Matthey quality and service How to Order/General Information ____________________________________________________IV through all stages of your project. Alfa Aesar carries a full Abbreviations and Codes _____________________________________________________________ 1 Introduction to Catalysis and Catalysts ________________________________________________ 3 range of Johnson Matthey catalysts in stock in smaller catalog pack sizes and semi-bulk quantities for immediate Precious Metal Compounds and Homogeneous Catalysts ____________________________ 19 shipment. Our worldwide plants have the stock and Asymmetric Hydrogenation Ligand/Catalyst Kit __________________________________________________ 57 Advanced Coupling Kit _________________________________________________________________________ 59 manufacturing capability to
    [Show full text]
  • The Radiochemistry of Palladium
    546.8 I H715r C.4 National ——.—.. Academy v of Sciences I National Research Council NUCLEAR SCIENCE SERIES The Radiochemistry of Palladium —--—.———- (’-_b 4 COMMITTEE ON NUCLEAR SCIENCE L. F. CURT1~, Chairman ROBLEY D. EVANS, Vice Chairman Ntiiond Bureau of -mda Maanachusetts fnat[tute of Technology J. A. DsJUREN, Secretary Weatlqghouse Electric Corprntlon C. J. BORKOWS~ J. W. fRVD?E. JR Oak Ridge Nationnl Iahoratory Maaeachusetb Imtitute of Technology ROBERT G. COCHRAN E. D. KLEMA Texas Agricultural and Mechanical NorthweBtmn Unfvem My Co-e W, WAYNE MINNKS UnlvarBity of MIChfEWJ SAMUEL EPSTELN California fnstltute of TechMloD J. J. NICKSON Memorfnl Hoapit81, New York U. FANO Natfoml Bureau of StandwdB ROBERT L. PLATZldAN Labomtdre de Chi!de Phydque EKRBKRT GOLDSTEIN Nuolear Development Corporntlon of D. M. VAN PATTER herion Bartol Resenrch Foundation LIAISON MEMBERS PAUL C. AEBZRMXD CHARLES K. REED Abmtc EneIw Comlniaalon U. S. Air Force J. HOWARD McWLLEN WTLLfAM E. WRIGRT National SaIence Foundation OffIce of Naval Reaearah SUBCOMMITTEE ON RADIOCHEMISTRY W. WAYNE MEDifCE, Chairman EARL HYDE Urdveraiiy of Michfgm Universi@ of California (Berkeley) NATHAN BALLCNJ JUfdAN Nf.S LSEN Navaf RMBolosfcal Defenm -mtnry Hardord fdnoratoriea GREGORY R. CHOPPfN G. DAvfD O’KELLEY Florida state Unfversi& Oak Rtdge Natfonal Latmra.tary GEORGE A COWAN ELLfs P. STEINBERG ba AlanOa S431entific J.ahOrato~ Argonne Nauonal Laboratory ARTHUR W. FAKFC-L4LL PETER C. STEVENSON Universi& of W88hir@0n Urdveri3ity of CaIifOrnia (Lfvermore) JEROME HUDIS DUANE N. SUNDERMAN Bmokhaven NatfonBI Lakmratory Batt8Lle Memorfal IUBtitute CONSULTANTS HERBERT M. CLARK JORN W. Winchester Rensseher Polytschnfc Iuatilute Maeaachuseti Inntitute of TechMlosY CHEMISTRY The Radiochemistry of palladium OVE T.
    [Show full text]
  • Palladium and Platinum Complexes for the Oxidation of Small Molecules
    PALLADIUM AND PLATINUM COMPLEXES FOR THE OXIDATION OF SMALL MOLECULES A DISSERTATION SUBMITTED TO THE DEPARTMENT OF CHEMISTRY AND THE COMMITTEE ON GRADUATE STUDIES OF STANFORD UNIVERSITY IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY David M. Pearson October 2010 © 2011 by David Michael Pearson. All Rights Reserved. Re-distributed by Stanford University under license with the author. This work is licensed under a Creative Commons Attribution- Noncommercial 3.0 United States License. http://creativecommons.org/licenses/by-nc/3.0/us/ This dissertation is online at: http://purl.stanford.edu/zn293zr6223 ii I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Robert Waymouth, Primary Adviser I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Eric Kool I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor of Philosophy. Barry Trost Approved for the Stanford University Committee on Graduate Studies. Patricia J. Gumport, Vice Provost Graduate Education This signature page was generated electronically upon submission of this dissertation in electronic format. An original signed hard copy of the signature page is on file in University Archives. iii Abstract Palladium is a versatile metal used prominently in synthesis. The rapid growth of palladium oxidation chemistry in the past decade has spurred a number of new processes that allow for the selective oxidation of substrates under mild conditions.
    [Show full text]
  • Catalytic Hydrogenation of Cyclohexene 3
    JOURNAL OF CATSLYSIS 52, 462-471 (1978) Catalytic Hydrogenation of Cyclohexene 3. Gus-Phase and Liquid-Phase Reaction on Supported Palladium E. E. GONZO AND M. BOUDART’ Department of C?Lemical Engineering, Stanford University, Stanford, California 94305 Received September 22, 1977; revised January 16, 1978 The hydrogenation of cyclohexene was studied in both gas and liquid phases on six different palladium catalysts supported on silica gel and alumina between 264 and 308 K at hydrogen pressures from 4 to 89 kPa, cyclohexene partial pressures from 0.46 to 1.5 kPa, and cyclohexene concentrations from 0.15 to 3.0 M. Under these conditions the turnover frequency is inde- pendent of particle size (1.5 to 10 nm) in both liquid and gas phases, of the nature of the support, and of the nature of nonaromatic solvents (methanol, n-heptane, ethyl acetate, and cyclo- hexene). The order of reaction was one-half with respect to hydrogen for the reaction in both liquid and gas phases and zero with respect to cyclohexene partial pressure (gas phase) or with respect to cyclohexene molar concent’ration (liquid phase). At the same temperature and hydrogen pressure, the turnover frequency was about twice as high in the gas phase as in the liquid phase. INTRODUCTION for the hydrogenation of cyclic olefins. In The mechanism of the hydrogenation of particular, with supported metals, it is of alkenes on metal catalysts has been the interest to determine the effect of metal subject of many investigations (1). In 1934, particle size on turnover frequency. We Polanyi and Horiuti (2) proposed a mecha- have reported recently the lack of such an nism for the hydrogenation of ethylene on effect for the hydrogenation of cyclohexene, the surface of metallic nickel.
    [Show full text]