Lithium Aluminium Hydride.Pdf
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Chapter 13.Pptx
Chapter 13: Alcohols and Phenols 13.1 Structure and Properties of Alcohols C C Alkanes Carbon - Carbon Multiple Bonds Carbon-heteroatom single bonds basic O C C C N C N C X O nitro alkane X= F, Cl, Br, I amines Alkenes Alkyl Halide Chapter 23 OH C C H O C O C C O C C Alkynes phenol alcohols ethers epoxide acidic Chapter 14 H H H C S C C C C S S C C S C C H C C sulfides thiols disulfide H H (thioethers) Arenes 253 Nomenclature of alcohols 1. In general, alcohols are named in the same manner as alkanes; replace the -ane suffix for alkanes with an -ol for alcohols CH3CH2CH2CH3 CH3CH2CH2CH2OH OH butane 1-butanol 2-butanol butan-1-ol butan-2-ol 2. Number the carbon chain so that the hydroxyl group gets the lowest number 3. Number the substituents and write the name listing the substituents in alphabetical order. Many alcohols are named using non-systematic nomenclature H C OH 3 OH OH C OH OH HO OH H3C HO H3C benzyl alcohol allyl alcohol tert-butyl alcohol ethylene glycol glycerol (phenylmethanol) (2-propen-1-ol) (2-methyl-2-propanol) (1,2-ethanediol) (1,2,3-propanetriol) 254 127 Alcohols are classified according to the H R C OH C OH H H degree of substitution of the carbon bearing H H 1° carbon the -OH group methanol primary alcohol primary (1°) : one alkyl substituent R R C OH C OH R R secondary (2°) : two alkyl substituents H R 2° carbon 3° carbon tertiary (3°) : three alkyl substituents secondary alcohol tertiary alcohol Physical properties of alcohols – the C-OH bond of alcohols has a significant dipole moment. -
Radical Approaches to Alangium and Mitragyna Alkaloids
Radical Approaches to Alangium and Mitragyna Alkaloids A Thesis Submitted for a PhD University of York Department of Chemistry 2010 Matthew James Palframan Abstract The work presented in this thesis has focused on the development of novel and concise syntheses of Alangium and Mitragyna alkaloids, and especial approaches towards (±)-protoemetinol (a), which is a key precursor of a range of Alangium alkaloids such as psychotrine (b) and deoxytubulosine (c). The approaches include the use of a key radical cyclisation to form the tri-cyclic core. O O O N N N O O O H H H H H H O N NH N Protoemetinol OH HO a Psychotrine Deoxytubulosine b c Chapter 1 gives a general overview of radical chemistry and it focuses on the application of radical intermolecular and intramolecular reactions in synthesis. Consideration is given to the mediator of radical reactions from the classic organotin reagents, to more recently developed alternative hydrides. An overview of previous synthetic approaches to a range of Alangium and Mitragyna alkaloids is then explored. Chapter 2 follows on from previous work within our group, involving the use of phosphorus hydride radical addition reactions, to alkenes or dienes, followed by a subsequent Horner-Wadsworth-Emmons reaction. It was expected that the tri-cyclic core of the Alangium alkaloids could be prepared by cyclisation of a 1,7-diene, using a phosphorus hydride to afford the phosphonate or phosphonothioate, however this approach was unsuccessful and it highlighted some limitations of the methodology. Chapter 3 explores the radical and ionic chemistry of a range of silanes. -
Reductions and Reducing Agents
REDUCTIONS AND REDUCING AGENTS 1 Reductions and Reducing Agents • Basic definition of reduction: Addition of hydrogen or removal of oxygen • Addition of electrons 9:45 AM 2 Reducible Functional Groups 9:45 AM 3 Categories of Common Reducing Agents 9:45 AM 4 Relative Reactivity of Nucleophiles at the Reducible Functional Groups In the absence of any secondary interactions, the carbonyl compounds exhibit the following order of reactivity at the carbonyl This order may however be reversed in the presence of unique secondary interactions inherent in the molecule; interactions that may 9:45 AM be activated by some property of the reacting partner 5 Common Reducing Agents (Borohydrides) Reduction of Amides to Amines 9:45 AM 6 Common Reducing Agents (Borohydrides) Reduction of Carboxylic Acids to Primary Alcohols O 3 R CO2H + BH3 R O B + 3 H 3 2 Acyloxyborane 9:45 AM 7 Common Reducing Agents (Sodium Borohydride) The reductions with NaBH4 are commonly carried out in EtOH (Serving as a protic solvent) Note that nucleophilic attack occurs from the least hindered face of the 8 carbonyl Common Reducing Agents (Lithium Borohydride) The reductions with LiBH4 are commonly carried out in THF or ether Note that nucleophilic attack occurs from the least hindered face of the 9:45 AM 9 carbonyl. Common Reducing Agents (Borohydrides) The Influence of Metal Cations on Reactivity As a result of the differences in reactivity between sodium borohydride and lithium borohydride, chemoselectivity of reduction can be achieved by a judicious choice of reducing agent. 9:45 AM 10 Common Reducing Agents (Sodium Cyanoborohydride) 9:45 AM 11 Common Reducing Agents (Reductive Amination with Sodium Cyanoborohydride) 9:45 AM 12 Lithium Aluminium Hydride Lithium aluminiumhydride reacts the same way as lithium borohydride. -
UNIT 6 ELEMENTS of GROUP 13 Structure 6.1 Introduction Objectives I 6.2 Oailcrence, Extraction and Uses Occurrec - Extraction Uses I 6.3 General Characteristics
UNIT 6 ELEMENTS OF GROUP 13 structure 6.1 Introduction Objectives I 6.2 Oailcrence, Extraction and Uses Occurrec - Extraction uses i 6.3 General Characteristics I - 6.5 Halides of Bpron anel Aluminium Halides of Boron Halides of Aluminium 6.6 Oxides of Boron and Aluminium I Boric Oxide Aluminium Oxide 6.7 Oxoacids of Boron and Borates 6.8 Borazine 6.9 Complexation Behaviour 6.10 Anomalous Behaviour of Boron 6.11 Summary 6.12 Terminal Questions 6.13- Answers ' -- 6.1 INTRODUCTION In the previous two units, you studied the main features of the chemistry of Group 1 and Group 2 elements, i.e. the alkali and the alkaline earth metals. In this unit you - will study the elements of Group 13, namely, boron, aluminium, gallium, indium and, thallium. While studying the alkali and alkaline earth metals, you have seen that all Zhe elements of these two groups are highly reactive metals and the first element of each group shows some differences from the rest. In Group 13, the differences between the first element and the remaining elements become so pronounced that the first member of the group, i.e. boron is a nonmetal wheieas the rest of the elements are distinctly metallic in nature. In a way, this is the first group of the periodic table in which you observe a marked change in the hature of the elements . down the group. describe the chemistry of hydrides, halides and oxides of boron and aluminium, elucidate the structures of hydrides of boron and aluminium, 6.2 OCCURRENC~,EXTRACTION AND USES Elements bf Group 13 are sufficiently reactive. -
Hydrogen Transmutation of Nickel in Glow Discharge
International Journal of Materials Science ISSN 0973-4589 Volume 12, Number 3 (2017), pp. 405-409 © Research India Publications http://www.ripublication.com Hydrogen Transmutation of Nickel in Glow Discharge Vladimir K. Nevolin National Research University of Electronic Technology (MIET), Moscow, Russia. Abstract Background: The possibility of the existence of subatomic hydrogen states was theoretically predicted previously. Objectives: Prove that the transmutation of elements is possible in specially prepared conditions for hydrogen. Methodology: By comparing the mass spectra of deposits on silicon substrates and target electrodes, it is shown that a change in the composition is observed in a magnetron Argon. Results: An increase in the concentration of 62 60 the nickel isotope 28 Ni and a decrease in the isotope concentration 28 Ni are shown. Conclusion: These results confirm the results obtained earlier in the heat generator Rossi, who worked more than a year, found an increase in the 62 isotope 28 Ni due to a decrease in the proportion of other isotopes. Keywords: transmutation, isotopes of nickel, glow discharge, argon, hydrogen INTRODUCION It is considered that the cold transmutation of elements (cold nuclear reactions) has been experimentally demonstrated [1]. On the basis of this phenomenon, energy generators are created in which long-term release of thermal energy in excess of expended energy is observed [2]. From many experimental studies it can be seen that hydrogen, which plays a pivotal role in the reaction zone, may be delivered through a variety of chemical compounds; for example, using lithium aluminium hydride LiAlH4. An analysis of the products of nuclear reactions suggests the possibility of many simultaneous nuclear fusion and decomposition reactions [3]. -
Lithium Hydride Powered PEM Fuel Cells for Long-Duration Small Mobile Robotic Missions
Lithium Hydride Powered PEM Fuel Cells for Long-Duration Small Mobile Robotic Missions Jekanthan Thangavelautham, Daniel Strawser, Mei Yi Cheung Steven Dubowsky Abstract— This paper reports on a study to develop power supplies for small mobile robots performing long duration missions. It investigates the use of fuel cells to achieve this objective, and in particular Proton Exchange Membrane (PEM) fuel cells. It is shown through a representative case study that, in theory, fuel cell based power supplies will provide much longer range than the best current rechargeable battery technology. It also briefly discusses an important limitation that prevents fuel cells from achieving their ideal performance, namely a practical method to store their fuel (hydrogen) in a form that is compatible with small mobile field robots. A very efficient Fig. 1. Example of small robots (Left) A ball shaped hopping robot concept fuel storage concept based on water activated lithium hydride for exploration of extreme terrains and caves developed for NASA. (Right) (LiH) is proposed that releases hydrogen on demand. This iRobot 110 Firstlook used for observation, security and search and rescue. concept is very attractive because water vapor from the air is passively extracted or waste water from the fuel cell is recycled and transferred to the lithium hydride where the hydrogen is the near future. Hence, new means for powering field robots “stripped” from water and is returned to the fuel cell to form more water. This results in higher hydrogen storage efficiencies need to be considered. than conventional storage methods. Experimental results are This paper explores the use of fuel cells, and in particular presented that demonstrate the effectiveness of the approach. -
WO 2015/177807 Al 26 November 2015 (26.11.2015) P O P C T
(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT) (19) World Intellectual Property Organization International Bureau (10) International Publication Number (43) International Publication Date WO 2015/177807 Al 26 November 2015 (26.11.2015) P O P C T (51) International Patent Classification: (81) Designated States (unless otherwise indicated, for every C07D 403/14 (2006.01) kind of national protection available): AE, AG, AL, AM, AO, AT, AU, AZ, BA, BB, BG, BH, BN, BR, BW, BY, (21) International Application Number: BZ, CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, PCT/IN20 15/000066 DO, DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT, (22) International Filing Date: HN, HR, HU, ID, IL, IN, IR, IS, JP, KE, KG, KN, KP, KR, 3 February 2015 (03.02.2015) KZ, LA, LC, LK, LR, LS, LU, LY, MA, MD, ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI, NO, NZ, OM, (25) Filing Language: English PA, PE, PG, PH, PL, PT, QA, RO, RS, RU, RW, SA, SC, (26) Publication Language: English SD, SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR, TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW. (30) Priority Data: 1709/MUM/2014 22 May 2014 (22.05.2014) (84) Designated States (unless otherwise indicated, for every kind of regional protection available): ARIPO (BW, GH, (71) Applicant: WANBURY LTD. [IN/IN]; BSEL tech park, GM, KE, LR, LS, MW, MZ, NA, RW, SD, SL, ST, SZ, B wing, 10th floor, sector 30A, opp. -
Boron- and Nitrogen-Based Chemical Hydrogen Storage Materials
international journal of hydrogen energy 34 (2009) 2303–2311 Available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/he Review Boron- and nitrogen-based chemical hydrogen storage materials Tetsuo Umegaki, Jun-Min Yan, Xin-Bo Zhang, Hiroshi Shioyama, Nobuhiro Kuriyama, Qiang Xu* National Institute of Advanced Industrial Science and Technology (AIST), 1-8-31 Midorigaoka, Ikeda, Osaka 563-8577, Japan article info abstract Article history: Boron- and nitrogen-based chemical hydrides are expected to be potential hydrogen Received 20 November 2008 carriers for PEM fuel cells because of their high hydrogen contents. Significant efforts have Accepted 4 January 2009 been devoted to decrease their dehydrogenation and hydrogenation temperatures and Available online 4 February 2009 enhance the reaction kinetics. This article presents an overview of the boron- and nitrogen-based compounds as hydrogen storage materials. Keywords: ª 2009 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights Boron-based chemical hydrides reserved. Nitrogen-based chemical hydrides Hydrogen storage Dehydrogenation Hydrogenation Ammonia borane 1. Introduction in operating the system at high temperature poses an obstacle to its practical application. Chemical hydrogen Hydrogen is a globally accepted clean fuel. The use of storage materials, due to their high hydrogen contents, are hydrogen fuel cells in portable electronic devices or vehicles expected as potential hydrogen sources for fuel cells. Among requires lightweight -
Common Name: LITHIUM ALUMINUM HYDRIDE HAZARD
Common Name: LITHIUM ALUMINUM HYDRIDE CAS Number: 16853-85-3 RTK Substance number: 1121 DOT Number: UN 1410 Date: April 1986 Revision: November 1999 ----------------------------------------------------------------------- ----------------------------------------------------------------------- HAZARD SUMMARY * Lithium Aluminum Hydride can affect you when * Exposure to hazardous substances should be routinely breathed in. evaluated. This may include collecting personal and area * Contact can cause severe skin and eye irritation and burns. air samples. You can obtain copies of sampling results * Breathing Lithium Aluminum Hydride can irritate the from your employer. You have a legal right to this nose and throat. information under OSHA 1910.1020. * Breathing Lithium Aluminum Hydride can irritate the * If you think you are experiencing any work-related health lungs causing coughing and/or shortness of breath. Higher problems, see a doctor trained to recognize occupational exposures can cause a build-up of fluid in the lungs diseases. Take this Fact Sheet with you. (pulmonary edema), a medical emergency, with severe shortness of breath. WORKPLACE EXPOSURE LIMITS * Exposure can cause loss of appetite, nausea, vomiting, The following exposure limits are for Aluminum pyro powders diarrhea and abdominal pain. (measured as Aluminum): * Lithium Aluminum Hydride can cause headache, muscle weakness, loss of coordination, confusion, seizures and NIOSH: The recommended airborne exposure limit is coma. 5 mg/m3 averaged over a 10-hour workshift. * High exposure can affect the thyroid gland function resulting in an enlarged thyroid (goiter). ACGIH: The recommended airborne exposure limit is * Lithium Aluminum Hydride may damage the kidneys. 5 mg/m3 averaged over an 8-hour workshift. * Lithium Aluminum Hydride is a REACTIVE CHEMICAL and an EXPLOSION HAZARD. -
A Passive Lithium Hydride Based Hydrogen Generator for Low Power Fuel Cells for Long-Duration Sensor Networks
international journal of hydrogen energy 39 (2014) 10216e10229 Available online at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/he A passive lithium hydride based hydrogen generator for low power fuel cells for long-duration sensor networks D. Strawser, J. Thangavelautham*, S. Dubowsky Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA article info abstract Article history: This paper focuses on developing an efficient fuel storage and release method for hydrogen Received 7 November 2013 using lithium hydride hydrolysis for use in PEM fuel cells for low power sensor network Received in revised form modules over long durations. Lithium hydride has high hydrogen storage density and 2 April 2014 achieves up to 95e100% yield. It is shown to extract water vapor freely from the air to Accepted 17 April 2014 generate hydrogen and has a theoretical fuel specific energy of up to 4900 Wh/kg. A critical Available online 23 May 2014 challenge is how to package lithium hydride to achieve reaction completion. Experiments here show that thick layers of lithium hydride nearly chokes the reaction due to buildup of Keywords: lithium hydroxide impeding water transport and preventing reaction completion. A model Hydrogen generator has been developed that describes this lithium hydride hydrolysis behavior. The model Lithium hydride accurately predicts the performance of an experimental system than ran for 1400 h and PEM consists of a passive lithium hydride hydrogen generator and PEM fuel cells. These results Sensor networks power supply offer important design guidelines to enable reaction completion and build long-duration Hydrolysis lithium hydride hydrogen generators for low power applications. -
A New Look at Lithium Hydride Chemical Biosensors Measure Brain Activity Recovering Infrastructure After a Biological Attack About the Cover
Lawrence Livermore National Laboratory October/November 2016 Also in this issue: A New Look at Lithium Hydride Chemical Biosensors Measure Brain Activity Recovering Infrastructure after a Biological Attack About the Cover Through a historic partnership between the Department of Energy (DOE) and the National Cancer Institute (NCI), Lawrence Livermore is applying its expertise in high-performance computing (HPC) to advance cancer research and treatment. As the article beginning on p. 4 describes, the Laboratory plays a crucial role in the partnership’s three pilot programs. In particular, Livermore experts are working in collaboration with NCI and other DOE labroatories to develop more advanced algorithms for improving predictive models, computational tools for better understanding cancer intiation, and data analytics techniques to search for patterns in vast amounts of patient data. The cover art combines an artist’s rendering of circulating tumor cells in the blood of a cancer patient with computer circuitry (representing HPC) in the background. Cover design: Amy E. Henke E. Amy design: Cover About S&TR At Lawrence Livermore National Laboratory, we focus on science and technology research to ensure our nation’s security. We also apply that expertise to solve other important national problems in energy, bioscience, and the environment. Science & Technology Review is published eight times a year to communicate, to a broad audience, the Laboratory’s scientific and technological accomplishments in fulfilling its primary missions. The publication’s goal is to help readers understand these accomplishments and appreciate their value to the individual citizen, the nation, and the world. The Laboratory is operated by Lawrence Livermore National Security, LLC (LLNS), for the Department of Energy’s National Nuclear Security Administration. -
Azidocinnamates in Heterocyclic Synthesis
AZIDOCINNAMATES IN HETEROCYCLIC SYNTHESIS A THESIS PRESENTED BY DEIRDRE M.B. HICKEY B.SC. FOR THE DEGREE OF DOCTOR OF PHILOSOPHY j UNIVERSITY OF LONDON Hofmann Laboratory, Department of Chemistry, Imperial College of Science and Technology, London, SW7 2AY. October, 1982. To my parents, Paddy and Thevese 3 with love and gratitude. ACKNOWLEDGEMENTS I thank Professor C.W. Rees for his enthusiastic supervision during the course of this work and my co-supervisor, Dr. C.J. Moody for his constant help and encouragement. I am grateful to Mr. P. Sulsh for technical help, to Mr. D. Neuhaus and Mr. R. Sheppard for Bruker n.m.r. spectra, to Mr. K. Jones for the analytical service, to Mr. J. Bilton, Mrs. Lee, and Mr. N. Davies for the mass spectroscopy service, and to Mr. D. Everitt in the Stores. Miss Moira Shanahan has expertly typed this thesis and I am grateful for her patience and perserverance. I thank Mr. Michael Casey for proof-reading this thesis and for his help and friendship for many years. Dr. Brian Bell I thank for his help and continued support during the production of this thesis. My colleagues on the seventh floor I will warmly remember for their friendship and comradeship. Finally, grateful acknowledgement is made to the Department of Chemistry, Imperial College for a research assistantship. iv ABSTRACT The reactions of various types of nitrenes to give heterocyclic products is reviewed. A series of vinyl azides, mostly ort/zo-substituted azidocinnamates, was prepared and their decomposition reactions studied. The thermal decomposition of ortho-alkyl azidocinnamates gave 2,4- disubstituted indoles, 1,3-disubstituted isoquinolines, 1,3-disubstituted -1,2-dihydroisoquinolines, and enamines, the amounts of each varying with the ortho-group and the conditions used, iodine having a marked effect on the product ratios.