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1 Introduction to Early Main Group Organometallic Chemistry and Catalysis
1 1 Introduction to Early Main Group Organometallic Chemistry and Catalysis Sjoerd Harder University Erlangen-Nürnberg, Inorganic and Organometallic Chemistry, Egerlandstrasse 1, 91058 Erlangen, Germany 1.1 Introduction Although organometallic complexes of the early main groups are well known for their very high reactivity and challenging isolation, they are among the first stud- ied during the pioneering beginnings of the field. Their high nucleophilicity and Brønsted basicity have made them to what they are today: strong polar reagents that are indispensible in modern organic synthesis. It is exactly this high reactivity that has made them potent catalysts for organic transformations that are gener- ally catalyzed by transition metal complexes. Despite their lack of partially filled d-orbitals and their inability to switch reversibly between oxidation states, the scope of their application in catalysis is astounding. As the early main group metal catalysis only started to become popular since the beginning of this century, it is still a young field with ample opportunities for further development. This intro- ductory chapter is specifically written for new graduate students in the field. It gives a very compact overview of the history of early main group organometallic chemistry, synthetic methods, bonding and structures, analytical methods, solu- tion dynamics, and some preliminary low-valent chemistry. This forms the basis for understanding their use in catalysis for which the basic steps are described in the second part of this chapter. For further in-depth information, the reader is referred to the individual chapters in this book. 1.2 s-Block Organometallics 1.2.1 Short History The organometallic chemistry of the highly electropositive early main group metals could not have started without the isolation of these elements in the metallic state. -
Lesson 4 Temperature Change TEACHER GUIDE
Lesson 4 Temperature change TEACHER GUIDE Lesson summary Students meet scientist Jason Williams, an industrial chemist who designs the materials and processes for making solar cells. He explains that during the summers, Antarctic days are very long, sometimes lasting a couple of weeks or more. That makes solar energy an abundant natural resource near the South Pole. Solar cells convert energy from the sun into electrical energy. Converting energy from one form to another is an important process. In the activity, students will conduct two chemical reactions that convert chemical energy into thermal energy. Key concepts + A change in temperature is a clue that a chemical reaction may have occurred. + When the temperature increases during a chemical reaction, it is called an exothermic reaction. + When the temperature decreases during a chemical reaction, it is called an endothermic reaction. + It takes energy to break chemical bonds in the reactants. + Energy is released when chemical bonds form in the products. Safety Be sure you and the students wear properly fitting goggles. Read and follow all safety warnings on the labels of the sodium bicarbonate, citric acid, calcium chloride, and universal indicator containers. Also follow the warnings on the packaging of the foot warmer. Have students wash their hands after the activity. Proper disposal At the end of the lesson, have students pour their used solutions in a waste container. The resulting solution from the final demo should be placed in this container, too. Then dispose of all of this liquid waste down the drain or according to local regulations. The left-over sodium bicarbonate, citric acid, and calcium chloride powders can be disposed of with the classroom trash. -
Page 1 of 13 Pleasersc Do Not Advances Adjust Margins
RSC Advances This is an Accepted Manuscript, which has been through the Royal Society of Chemistry peer review process and has been accepted for publication. Accepted Manuscripts are published online shortly after acceptance, before technical editing, formatting and proof reading. Using this free service, authors can make their results available to the community, in citable form, before we publish the edited article. This Accepted Manuscript will be replaced by the edited, formatted and paginated article as soon as this is available. You can find more information about Accepted Manuscripts in the Information for Authors. Please note that technical editing may introduce minor changes to the text and/or graphics, which may alter content. The journal’s standard Terms & Conditions and the Ethical guidelines still apply. In no event shall the Royal Society of Chemistry be held responsible for any errors or omissions in this Accepted Manuscript or any consequences arising from the use of any information it contains. www.rsc.org/advances Page 1 of 13 PleaseRSC do not Advances adjust margins RSC Advances REVIEW Applications of supramolecular capsules derived from resorcin[4]arenes, calix[n]arenes and metallo-ligands: from Received 00th January 20xx, Accepted 00th January 20xx biology to catalysis a a,b a DOI: 10.1039/x0xx00000x Chiara M. A. Gangemi, Andrea Pappalardo* and Giuseppe Trusso Sfrazzetto* www.rsc.org/ Supramolecular architectures developed after the initial studies of Cram, Lehn and Pedersen have become structurally complexes but fascinating. In this context, supramolecular capsules based on resorcin[4]arenes, calix[n]arenes or metal- ligand structures are dynamic assemblies inspired to biological systems. -
Organometallic Catalysts in Synthetic Organic Chemistry: from Reactions in Aqueous Media to Gold Catalysis*
Pure Appl. Chem., Vol. 80, No. 5, pp. 831–844, 2008. doi:10.1351/pac200880050831 © 2008 IUPAC Organometallic catalysts in synthetic organic chemistry: From reactions in aqueous media to gold catalysis* Jean-Pierre Genêt‡, Sylvain Darses, and Véronique Michelet Selective Organic Synthesis and Natural Products Laboratory, Ecole Nationale Supérieure de Chimie de Paris, UMR CNRS 7573, 11 rue P. et M. Curie, 75231 Paris Cedex 05, France Abstract: Water has attracted significant attention as an alternative solvent for transition- metal-catalyzed reactions. The use of water as solvent allows simplified procedures for sep- aration of the catalyst from the products and recycling of the catalyst. Water is an inexpen- sive reagent for the formation of oxygen-containing products such as alcohols. The use of water as a medium for promoting organometallic and organic reactions is also of great po- tential. This chapter will focus on old and recent developments in the design and applications of some catalytic reactions using aqueous-phase Pd, Rh, Pt, and Au complexes. Keywords: water; catalysis; palladium; gold; rhodium; potassium organotrifluoroborates; asymmetric 1,4-addition; recycling. INTRODUCTION Over the past few years, significant research has been directed toward the development of new tech- nologies for environmentally benign processes. The use of water as solvent in homogeneous metal-cat- alyzed reactions has gained increasing attention because of the potential environmental and economic benefits of replacing organic solvents with water. Indeed, water is an attractive solvent because it is in- expensive and nontoxic; the most attractive feature is its utility in the development of green and envi- ronmentally safe processes [1]. -
Comparison of the Results from Six Calorimeters in the Determination of the Thermokinetics of a Model Reaction Wassila Benaissa, Douglas Carson
Comparison of the results from six calorimeters in the determination of the thermokinetics of a model reaction Wassila Benaissa, Douglas Carson To cite this version: Wassila Benaissa, Douglas Carson. Comparison of the results from six calorimeters in the determina- tion of the thermokinetics of a model reaction. AIChE Spring Meeting 2011 & 7. Global Congress on Process Safety (GCPS), Mar 2011, Chicago, United States. pp.NC. ineris-00976225 HAL Id: ineris-00976225 https://hal-ineris.archives-ouvertes.fr/ineris-00976225 Submitted on 9 Apr 2014 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. Comparison of the Results from Six Calorimeters in the Determination of the Thermokinetics of a Model Reaction Wassila BENAISSA INERIS Parc Technologique Alata BP 2, F-60550 Verneuil-en-Halatte [email protected] Douglas CARSON INERIS Keywords: calorimeter, thermal runway, kinetics Abstract This paper deals with the comparison of experimental results from several types of commercially available calorimeters: a screening calorimeter (DSC), a Calvet calorimeter (C80), a reaction calorimeter (RC1), and various pseudo-adiabatic calorimeters (VSP 2, ARSST, and Phi-Tec 1). One exothermic reaction was selected as a case study: the esterification of acetic anhydride by methanol, a system which has been well studied in the literature. -
Comprehensive Organometallic Chemistry II a Review of the Literature 1982-1994
Comprehensive Organometallic Chemistry II A Review of the Literature 1982-1994 Editors-in-Chief Edward W. Abel University ofExeter, UK F. Gordon A. Stone Baylor University, Waco, TX, USA Geoffrey Wilkinson Imperial College of Science, Technology and Medicine, London, UK Volume 1 LITHIUM, BERYLLIUM, AND BORON GROUPS Volume Editor Catherine E. Housecroft Institut für Anorganische Chemie der Universität Basel, Switzerland PERGAMON Contents of All Volumes Volume 1 Lithium, Beryllium, and Boron Groups 1 Alkali Metals 2 Beryllium 3 Magnesium, Calcium, Strontium and Barium 4 Compounds with Three- or Four-coordinate Boron, Emphasizing Cyclic Systems 5 Boron Rings Ligated to Metals 6 Polyhedral Carbaboranes 7 Main-group Heteroboranes 8 Metallaboranes 9 Transition Metal Metallacarbaboranes 10 Aluminum 11 Gallium, Indium and Thallium, Excluding Transition Metal Derivatives 12 Transition Metal Complexes of Aluminum, Gallium, Indium and Thallium Author Index Subject Index Volume 2 Silicon Group, Arsenic, Antimony, and Bismuth 1 Organosilanes 2 Carbacyclic Silanes 3 Organopolysilanes 4 Silicones 5 Germanium 6 Tin 7 Lead 8 Arsenic, Antimony and Bismuth Author Index Subject Index Volume 3 Copper and Zinc Groups 1 Gold 2 Copper and Silver 3 Mercury 4 Cadmium and Zinc Author Index Subject Index Volume 4 Scandium, Yttrium, Lanthanides and Actinides, and Titanium Group 1 Zero Oxidation State Complexes of Scandium, Yttrium and the Lanthanide Elements 2 Scandium, Yttrium, and the Lanthanide and Actinide Elements, Excluding their Zero Oxidation State Complexes -
The Use of Accelerating Rate Calorimetry (ARC) for the Study of the Thermal Reactions of Li-Ion Battery Electrolyte Solutions J.S
Journal of Power Sources 119–121 (2003) 794–798 The use of accelerating rate calorimetry (ARC) for the study of the thermal reactions of Li-ion battery electrolyte solutions J.S. Gnanaraja, E. Zinigrada, L. Asrafa, H.E. Gottlieba, M. Sprechera, D. Aurbacha,*, M. Schmidtb aDepartment of Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel bMerck KGaA, D-64293 Darmstadt, Germany Abstract The thermal stability of 1M LiPF6, LiClO4, LiN(SO2CF2CF3)2 (LiBETI) and LiPF3(CF2CF3)3 (LiFAP) solutions in mixtures of ethylene carbonate, diethyl carbonate and dimethyl carbonate in the temperature range 40–350 8C was studied by ARC and DSC. NMR was used to analyze the reaction products at different reaction stages. The least thermally stable are LiClO4 solutions. LiPF3(CF2CF3)3 solutions showed higher thermal stability than LiPF6 solutions. The highest thermal stability was found for LiN(SO2CF2CF3)2 solutions. Studies by DSC and pressure measurements during ARC experiments with LiPF6 and LiFAP solutions detected an endothermic reaction, which occurs before a number of exothermic reactions as the temperature increases. Fluoride ions are formed and react with the alkyl carbonate molecules both as bases and as nucleophiles. # 2003 Elsevier Science B.V. All rights reserved. Keywords: Accelerating rate calorimetry (ARC); Differential scanning calorimetry (DSC); Thermal stability; Alkyl carbonate solutions 1. Introduction 2. Experimental Accelerating rate calorimetry (ARC) is an important One molar LiPF6, LiClO4, LiN(SO2CF2CF3)2 and method for studying the thermal behavior of materials LiPF3(CF2CF3)3 solutions in mixture of ethylene carbonate [1,2]. LiPF6 solutions in alkyl carbonates are widely used (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC) in commercial Li-ion batteries in spite of their relatively low (2:1:2 v/v/v) were obtained from Merck KGaA (highly pure, thermal stability. -
Chemical Reactions Involve Energy Changes
Page 1 of 6 KEY CONCEPT Chemical reactions involve energy changes. BEFORE, you learned NOW, you will learn • Bonds are broken and made • About the energy in chemical during chemical reactions bonds between atoms • Mass is conserved in all • Why some chemical reactions chemical reactions release energy • Chemical reactions are • Why some chemical reactions represented by balanced absorb energy chemical equations VOCABULARY EXPLORE Energy Changes bond energy p. 86 How can you identify a transfer of energy? exothermic reaction p. 87 endothermic reaction p. 87 PROCEDURE MATERIALS photosynthesis p. 90 • graduated cylinder 1 Pour 50 ml of hot tap water into the cup • hot tap water and place the thermometer in the cup. • plastic cup 2 Wait 30 seconds, then record the • thermometer temperature of the water. • stopwatch • plastic spoon 3 Measure 5 tsp of Epsom salts. Add the Epsom salts to the beaker and immedi- • Epsom salts ately record the temperature while stirring the contents of the cup. 4 Continue to record the temperature every 30 seconds for 2 minutes. WHAT DO YOU THINK? • What happened to the temperature after you added the Epsom salts? • What do you think caused this change to occur? Chemical reactions release or absorb energy. COMBINATION NOTES Chemical reactions involve breaking bonds in reactants and forming Use combination notes new bonds in products. Breaking bonds requires energy, and forming to organize information on how chemical reactions bonds releases energy. The energy associated with bonds is called bond absorb or release energy. energy. What happens to this energy during a chemical reaction? Chemists have determined the bond energy for bonds between atoms. -
5.3 Controlling Chemical Reactions Vocabulary: Activation Energy
5.3 Controlling Chemical Reactions Vocabulary: Activation energy – Concentration – Catalyst – Enzyme – Inhibitor - How do reactions get started? Chemical reactions won’t begin until the reactants have enough energy. The energy is used to break the chemical bonds of the reactants. Then the atoms form the new bonds of the products. Activation Energy is the minimum amount of energy needed to start a chemical reaction. All chemical reactions need a certain amount of activation energy to get started. Usually, once a few molecules react, the rest will quickly follow. The first few reactions provide the activation energy for more molecules to react. Hydrogen and oxygen can react to form water. However, if you just mix the two gases together, nothing happens. For the reaction to start, activation energy must be added. An electric spark or adding heat can provide that energy. A few of the hydrogen and oxygen molecules will react, producing energy for even more molecules to react. Graphing Changes in Energy Every chemical reaction needs activation energy to start. Whether or not a reaction still needs more energy from the environment to keep going depends on whether it is exothermic or endothermic. The peaks on the graphs show the activation energy. Notice that at the end of the exothermic reaction, the products have less energy than the reactants. This type of reaction results in a release of energy. The burning of fuels, such as wood, natural gas, or oil, is an example of an exothermic reaction. Endothermic reactions also need activation energy to get started. In addition, they need energy to continue. -
Organometallic Chemistry BASIC PRINCIPLES, APPLICATIONS, and a FEW CASE STUDIES
Safety Moment TYLER LAB GROUP MEETING 1 Safety Moment TYLER LAB GROUP MEETING 2 Metal Hydrides: Benchtop vs. Box Hydride = :H- Hydrides are powerful Lewis bases and reducing agent ◦ Exothermically form H2 (this should scare you) ◦ Heating leads to faster reactivity ◦ H evolution leads to rapid increase in pressure2 ◦ Uncontrolled reactions easily cause runaway exotherm, class D fire, explosion, and death/unemployment LiAlH is the #1 chemical cause of fatality in chemical4 industry 3 Metal Hydrides: “I want to commit the murder I was imprisoned for†.” LiAlH4 ◦ Insanely irritating (serious safety hazard) ◦ Extremely moisture sensitive (don’t leave out for >2 minutes) ◦ Ethereal mixtures are pyrophoric! DiBuAl-H ◦ Pyrophoric – it will explode upon exposure to oxygen NaEt3BH ◦ Pyrophoric in solution LiH and NaH ◦ Can be handled on the benchtop (not >2 minutes) ◦ Parrafin oil dispersions much safer KH ◦ Pyrophoric if not in a dispersion ◦ Handle with extreme care! † Sirius Black, Harry Potter and the Prisoner of Azkaban 4 Metal Hydrides: “I want to commit the murder I was imprisoned for†.” CaH2 ◦ Very safe to handle on the benchtop Pt-H, Pd-H, Ni-H ◦ All very pyrophoric NaBH4 ◦ Very safe in general Other hydrides ◦ Treat as pyrophoric ◦ Transition metal hydrides vary in hydridic strength ◦ General rule of thumb: if it does hydrogenations, it is probably pyrophoric ◦ If they’re in organics of any kind, they are probably pyrophoric † Sirius Black, Harry Potter and the Prisoner of Azkaban 5 Organometallic Chemistry BASIC PRINCIPLES, APPLICATIONS, -
13 Energetics
13 Energetics All chemical substances contain energy stored in their bonds. When a chemical reaction occurs, there is usually a change in energy between the reactants and products. This is normally in the form of heat energy, but may also be in the form of light, nuclear or electrical energy. Exothermic and endothermic reactions Based on energy changes occurring, reactions can be of two types: • An exothermic reaction produces heat which causes the reaction mixture and its surroundings to get hotter (it releases energy to the surroundings). Exothermic reactions include neutralisation reactions, burning fossil fuels and respiration in cells. • An endothermic reaction absorbs heat which causes the reaction mixture and its surroundings to get colder (it absorbs energy from the surroundings). Endothermic reactions include dissolving certain salts in water, thermal decomposition reactions and photosynthesis in plants. Breaking and forming bonds during reactions During any chemical reaction, existing bonds in the reactants are broken and new bonds are formed in the products: • Energy is absorbed when the existing bonds in the reactants are broken. • Energy is released when new bonds are formed in the products: reactants products existing bonds are broken new bonds are formed energy is absorbed energy is released • In an exothermic reaction: energy absorbed to break bonds < energy released when forming bonds The extra energy is released to the surroundings causing the temperature of the surroundings to increase. • In an endothermic reaction: energy absorbed to break bonds > energy released when forming bonds The extra energy is absorbed from the surroundings causing the temperature of the surroundings to decrease. -
Lab.9. Calorimetry
Lab.6. Thermodynamics, Calorimetry Key words: Heat, energy, exothermic & endothermic reaction, calorimeter, calorimetry, enthalpy of reaction, specific heat, chemical & physical change, enthalpy of neutralization, law of conservation of energy, final temperature, initial temperature, lattice energy, hydratation energy, enthalpy of solution Literature: J. A. Beran; Laboratory Manual for Principles of General Chemistry, pp. 245-256. J.E. Brady, F. Senese: Chemistry – Matter and its Changes, 4th ed. Wiley 2003, Chapters 7, 20, . M. Hein and S. Arena: Introduction to Chemistry, 13th ed. Wiley 2011; pp. 157 - 161 J. Crowe. T. Bradshaw, P. Monk, Chemistry for the Biosciences. The essential concepts., Oxford University Press, 2006; pp. 416 - 450. J. Brady, N. Jespersen, A. Hysop, Chemistry, International Student Version, 7thed. Wiley, 2015, Chapter 18, 855 – 890. Theoretical background Accompanying all chemical and physical changes is a transfer of heat (energy); heat may be either evolved (exothermic) or absorbed (endothermic). A calorimeter (Fig. 1) is the laboratory apparatus that is used to measure the quantity and direction of heat flow accompanying a chemical or physical change. The calorimeter is well-insulated so that, ideally, no heat enters or leaves the calorimeter from the surroundings. For this reason, any heat liberated by the reaction or process being studied must be picked up by the calorimeter and other substances in the calorimeter. The heat change in chemical reactions is quantitatively expressed as the enthalpy (or heat) of reaction, H, at constant pressure. H values are negative for exothermic reactions and positive for endothermic reactions. Lab.6. Thermodynamics, Calorimetry Fig. 1. A set nested coffee cups is a good constant pressure calorimeter.