DOCSLIB.ORG

Environmental Risk Assessment Report: Decamethylcyclopentasiloxane

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Environmental Risk Assessment Report: Decamethylcyclopentasiloxane Environmental Risk Assessment Report: Decamethylcyclopentasiloxane Science Report Environmental Risk Assessment: Decamethylcyclopentasiloxane 1 The Environment Agency is the leading public body protecting and improving the environment in England and Wales. It’s our job to make sure that air, land and water are looked after by everyone in today’s society, so that tomorrow’s generations inherit a cleaner, healthier world. Our work includes tackling flooding and pollution incidents, reducing industry’s impacts on the environment, cleaning up rivers, coastal waters and contaminated land, and improving wildlife habitats. Published by: Author(s): Environment Agency, Rio House, Waterside Drive, Aztec West, Brooke D N, Crookes M J , Gray D and Robertson S Almondsbury, Bristol, BS32 4UD Tel: 01454 624400 Fax: 01454 624409 Dissemination Status: www.environment-agency.gov.uk Publicly available / released to all regions ISBN: 978-1-84911-029-7 Keywords: © Environment Agency April 2009 Decamethylcyclosiloxane, siloxane All rights reserved. This document may be reproduced with prior Research Contractor: permission of the Environment Agency. Building Research Establishment Ltd, Bucknalls Lane, Garston, Watford, WD25 9XX. Tel. 01923 664000 The views expressed in this document are not necessarily those of the Environment Agency. Environment Agency’s Project Manager: Steve Robertson, Chemicals Assessment Unit, Red Kite House, This report is printed on Cyclus Print, a 100 per cent recycled Howbery Park, Wallingford OX10 8BD. Tel 01491 828555 stock, which is 100 per cent post consumer waste and is totally chlorine free. Water used is treated and in most cases returned Collaborator(s): to source in better condition than removed. D Gray, Health and Safety Executive Further copies of this report are available from: Product code: The Environment Agency’s National Customer Contact Centre SCHO0309BPQX-E-P by emailing [email protected] or by telephoning 08708 506506. Science Report Environmental Risk Assessment: Decamethylcyclopentasiloxane 2 Science at the Environment Agency Science underpins the work of the Environment Agency, by providing an up to date understanding of the world about us, and helping us to develop monitoring tools and techniques to manage our environment as efficiently as possible. The work of the Science Department is a key ingredient in the partnership between research, policy and operations that enables the Agency to protect and restore our environment. The Environment Agency’s Science Group focuses on five main areas of activity: • Setting the agenda: To identify the strategic science needs of the Agency to inform its advisory and regulatory roles. • Sponsoring science: To fund people and projects in response to the needs identified by the agenda setting. • Managing science: To ensure that each project we fund is fit for purpose and that it is executed according to international scientific standards. • Carrying out science: To undertake the research itself, by those best placed to do it - either by in-house Agency scientists, or by contracting it out to universities, research institutes or consultancies. • Providing advice: To ensure that the knowledge, tools and techniques generated by the science programme are taken up by relevant decision- makers, policy makers and operational staff. Steve Killeen Head of Science Science Report Environmental Risk Assessment: Decamethylcyclopentasiloxane 3 Executive Summary The Environment Agency’s environmental risk assessment for decamethylcyclopentasiloxane (D5) is based on the methods outlined in the European Union (EU) Technical Guidance Document for the risk assessment of new and existing chemicals. The persistence, bioaccumulative, and toxic (PBT) status is assessed, and a ‘quantitative’ risk assessment made by comparison of exposure with effects. Persistence, bioaccumulative, and toxic status D5 meets the screening criteria for a very persistent (vP) and very bioaccumulative (vB) substance. It is unlikely to meet the screening criteria for persistent organic pollutants in long-range transport. Laboratory studies indicate that D5 is not readily biodegradable in aquatic systems. However, it is difficult to interpret some of the results because of the rapid loss of D5 through volatilisation. A standard test modified to prevent such loss gives a hydrolysis pH- dependent half-life of 71 days at pH 7 and nine days at pH 8 (both at 25°C). The equivalent half-life at pH 7 and12°C is estimated to be around 315 days, and those at higher pHs (e.g. around 8, as can occur in the marine environment) and 9°C are estimated as 64 days. The final products of the hydrolysis of D5 are not thought to have PBT properties. The lack of biodegradation in laboratory tests and the relatively slow rate of hydrolysis at pHs around 7 mean D5 meets the persistent and vP criteria for water. Although, the volatility of D5 affects its residence time in water–sediment systems, and is probably the predominant removal mechanism for D5 from water, adsorption onto sediments also occurs. D5 lost to air because of its high volatility undergoes subsequent degradation in the air. The bioconcentration factor (BCF) for BCF of D5 in fish is 7060 l/kg (determined experimentally). In addition, D5 is accumulated by fish from diet, and a growth-corrected and lipid-normalised biomagnification factor (BMF) of 3.9 is derived from the available experimental data. Thus, D5 meets the vB criterion. D5 shows essentially no acute toxicity to aquatic organisms when tested at concentrations up to its water solubility limit, as do the limited long-term toxicity data available. In addition, D5 is not classified as a carcinogenic, mutagenic, or reprotoxic compound. Based on these data D5 does not meet the toxic criterion. However, the available long-term fish toxicity data may not cover all of the relevant toxicological endpoints, so it is not fully established whether or not D5 has the potential to cause effects in fish over long-term exposure. For example, a recent accumulation study with fish shows only slow depuration of accumulated D5 from the liver, and the long-term impact of the accumulation in liver of fish is not known. In addition, effects on liver weight occur in rats at relatively low doses of D5. However, it is not clear if these effects alone are sufficient to warrant D5 as toxic. The overall conclusions of the PBT assessment are: • D5 meets the screening criteria for vPvB substances but some mitigating factors need to be considered further, in particular that D5 is lost from water by volatilisation to the air, where subsequent degradation occurs. Science Report Environmental Risk Assessment: Decamethylcyclopentasiloxane 4 • The current criteria for persistence are related to degradation half-lives in each individual compartment (aquatic, sediment, etc.). These may not be the most appropriate for a substance such as D5 as it is likely to be removed from the aquatic compartment more rapidly by physical process than by degradation. Thus, the overall persistence of the substance, including the potential for transport over distances and the effects at remote locations, needs to be assessed. Currently there are no criteria for this, so both further scientific discussion and consideration at a policy level are required. • Uncertainties exist over the long-term toxicity of D5 to fish. Available data suggest that it shows no adverse effects at concentrations up to its water solubility, but these data may not cover all the relevant toxicological endpoints. Further long-term toxicity testing with fish will reduce these uncertainties, but the actual need for such tests is unclear. Quantitative risk assessment The risks from the normal use of D5 to water, sediments, soil, and predators are assessed using standard models and the information available. The property data set is reasonably complete, but in some areas further information will be valuable. This assessment therefore makes recommendations about the significance of gaps and or uncertainties in the data, and suggests where further research should be focussed. The main uses of D5 are as an intermediate for the production of other chemicals (silicone polymers), in personal care products (e.g. cosmetic products and skin- and hair-care products), in household products, and in industrial/institutional cleaning. Use as an intermediate in the formation of silicone polymers effectively consumes the D5, although trace amounts in the final products can be subsequently released to the environment. Use of D5 in personal care and household products results in widespread exposure to the environment. Estimates of the potential emissions to the environment from D5’s key life-cycle stages are based on industry research and Emission Scenario Documents, or, in the absence of any other information, worst-case default assumptions. Monitoring data available for some life- cycle stages are taken into account where relevant. Risk characterisation ratios above one indicate an unacceptable risk for the environment and are identified for some life-cycle stages relevant to the UK. Some information provided by industry is treated as confidential and not given in this report, although the data are used to develop appropriate emission scenarios. These data are included in a confidential annex that supports the assessment, which is available via the Project Manager where appropriate. The overall conclusions of the quantitative risk assessment are: • No risks are identified to the air, water, and
Load more

Recommended publications
  • Transport of Dangerous Goods
    ST/SG/AC.10/1/Rev.16 (Vol.I) Recommendations on the TRANSPORT OF DANGEROUS GOODS Model Regulations Volume I Sixteenth revised edition UNITED NATIONS New York and Geneva, 2009 NOTE The designations employed and the presentation of the 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. ST/SG/AC.10/1/Rev.16 (Vol.I) Copyright © United Nations, 2009 All rights reserved. No part of this publication may, for sales purposes, be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, electrostatic, magnetic tape, mechanical, photocopying or otherwise, without prior permission in writing from the United Nations. UNITED NATIONS Sales No. E.09.VIII.2 ISBN 978-92-1-139136-7 (complete set of two volumes) ISSN 1014-5753 Volumes I and II not to be sold separately FOREWORD The Recommendations on the Transport of Dangerous Goods are addressed to governments and to the international organizations concerned with safety in the transport of dangerous goods. The first version, prepared by the United Nations Economic and Social Council's Committee of Experts on the Transport of Dangerous Goods, was published in 1956 (ST/ECA/43-E/CN.2/170). In response to developments in technology and the changing needs of users, they have been regularly amended and updated at succeeding sessions of the Committee of Experts pursuant to Resolution 645 G (XXIII) of 26 April 1957 of the Economic and Social Council and subsequent resolutions.
    [Show full text]
  • The Unique Properties of Siloxanes
    THE UNIQUE PROPERTIES OF SILOXANES This factsheet explains what makes siloxanes unique. Want to know how siloxanes are different from carbon-based materials? Or why they behave differently in the environment? Read on to find out more, including why the current PBT assessment criteria might not be suitable for them. WHAT ARE SILOXANES? Siloxanes are a group of substances characterized by a chain of alternating silicon (Si) and oxygen (O) atoms. Within the group, individual siloxane substances differ in size, weight and shape. They form the backbone of silicone polymers that are used in a variety of applications such as sealants, adhesives, coatings, plastics, cosmetics, medical devices, hygiene products, food contact materials, and many other industrial applications. Siloxane functional group Octamethylcyclotetrasiloxane (D4) WHAT ARE SILICONE POLYMERS? The structure and functionality of these chemical compounds drive the specific Silicones are specialty products that are used in small amounts in hundreds combination of properties of siloxanes of applications where their special performance is needed. They are used as including: adhesives, they create flow, they insulate, and they have excellent mechanical/ optical/thermal resistance among many other properties. Silicone polymers can • High propensity to repel water have very different forms depending on how they are built, for example: • Low water solubility • Volatility USED AS LUBRICANTS AND LIQUIDS/OIL IN HYDRAULIC FLUIDS Silicone materials offer a host of useful characteristics including:
    [Show full text]
  • Development of Novel Cycloaliphatic Siloxanes for Thermal
    DEVELOPMENT OF NOVEL CYCLOALIPHATIC SILOXANES FOR THERMAL AND UV-CURABLE APPLICATIONS A Dissertation Presented to The Graduate Faculty of the University of Akron In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Ruby Chakraborty May, 2008 DEVELOPMENT OF NOVEL CYCLOALIPHATIC SILOXANES FOR THERMAL AND UV-CURABLE APPLICATIONS Ruby Chakraborty Dissertation Approved: Accepted: _____________________________ ______________________________ Advisor Department Chair Dr. Mark D. Soucek Dr. Sadhan C. Jana ______________________________ ______________________________ Committee Member Dean of the College Dr. Sadhan C. Jana Dr. Stephen Cheng ______________________________ ______________________________ Committee Member Dean of the Graduate School Dr. Erol Sancaktar Dr. George R. Newkome ______________________________ ______________________________ Committee Member Date Dr. George G. Chase ______________________________ Committee Member Dr. Chrys Wesdemiotis ii ABSTRACT Siloxanes have been extensively used as additives to modulate surface properties such as surface tension, hydrophobicity/hydrophobicity, and adhesion, etc. Although, polydimethyl -siloxane and polydiphenylsiloxane are the most commonly used siloxanes, the properties are at extremes in terms of glass transition temperature and flexibility. It is proposed that the ability to control the properties in between the these extremes can be provided by cycloaliphatic substitutions at the siloxane backbone. It is expected that this substitution might work due to the intermediate backbone rigidity. In order to achieve the above objectives, a synthetic route was developed to prepare cycloaliphatic (cyclopentane and cyclohexane) silane monomers followed by subsequent polymerization and functionalizations to obtain glycidyl epoxy, aliphatic amine and methacrylate telechelic siloxanes. The siloxanes were either thermally or UV- cured depending on end functionalizations. Chemical characterization of monomers, oligomers and polymers were performed using 1H, 13C, 29Si-NMR, FT-IR and GPC.
    [Show full text]
  • Functionalized Hybrid Silicones – Catalysis, Synthesis and Application
    Technische Universität München Fakultät für Chemie Fachgebiet Molekulare Katalyse Functionalized Hybrid Silicones – Catalysis, Synthesis and Application Sophie Luise Miriam Putzien Vollständiger Abdruck der von der Fakultät für Chemie der Technischen Universität München zur Erlangung des akademischen Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) genehmigten Dissertation. Vorsitzender: Univ.-Prof. Dr. M. Schuster Prüfer der Dissertation: 1. Univ.-Prof. Dr. F. E. Kühn 2. Univ.-Prof. Dr. O.Nuyken (i.R.) Die Dissertation wurde am 16.02.2012 bei der Technischen Universität München eingereicht und durch die Fakultät für Chemie am 08.03.2012 angenommen. The following dissertation was prepared between April 2009 and March 2012 at the Chair of Inorganic Chemistry, Department of Molecular Catalysis of the Technische Universität München. I would like to express my deep gratitude to my academic supervisor Prof. Dr. Fritz E. Kühn for his support and confidence and the freedom of scientific research. This work was supported by a research grant from the BASF Construction Chemicals GmbH, Trostberg, Germany. Acknowledgement I would like to express my sincere gratitude to Prof. Dr. Oskar Nuyken and Dr. Eckhart Louis for their ongoing support and their undamped enthusiasm for my research topic. They supported this work with many inspiring discussions, new ideas and critical questions. I thank the BASF Construction Chemicals GmbH, Trostberg, for giving me the opportunity to work on an industrial cooperation project. Especially, I would like to thank Dr. Simone Klapdohr and Dr. Burkhard Walther, who accompanied this project from the industrial perspectice, for their support and the nice time I had in Trostberg during the application technological tests.
    [Show full text]
  • Silicone Elastomers with Exceptional Elongation ACS Rubber
    Silicone Elastomers with Exceptional Elongation Barry Arkles*, Jonathan Goff, Santy Sulaiman Gelest Inc. 11 East Steel Rd. Morrisville, PA 19067 Presented at the 188th Technical Meeting of Rubber Division, ACS / International Elastomer Conference Paper # 124 October 12-15, 2015 Cleveland, OH *Speaker 1 ABSTRACT Polysiloxanes elastomers formed by the step-growth of heterobifunctional macromers achieve high molecular weights and show elastomeric behavior. There is no apparent mechanism for crosslinking and advanced NMR and DSC techniques as well as rheological studies support the fact that, within the limits of detection, the step-growth elastomers are linear. When formed into nanocomposites by the incorporation of surface passivated fumed silica, they exhibit elongations exceeding 5000%. At extensions comparable to conventional silicone elastomers, they show similar elastic recovery. At greater extensions, recovery is reduced marginally. These materials are readily manufacturable and can be compounded and processed similar to conventional two-component platinum cure silicone RTVs. We have adopted the designation of xPDMS for these materials, a modified acronym for “high eXtension PolyDiMethylSiloxanes”. The synthesis, characterization, and mechanical properties of the first example of of an xPDMS suitable for commercial production is presented. INTRODUCTION In most commercial applications, single component silicone elastomers are conventionally prepared by either the crosslinking of a polysiloxane component in a silica reinforced base by a peroxide (HCR, high consistency rubber) or by a moisture-cure mechanism (condensation RTVs, room temperature vulcanizates)1. Another more flexible approach for commercial fabrication of silicone elastomers is to use two polysiloxane components in which 2 one polysiloxane component is generally of higher molecular weight and can be thought of the matrix polymer, and the second polysiloxane component, which is generally of lower molecular weight and can be thought of as a crosslinker.
    [Show full text]
  • Polyorganosiloxanes: Molecular Nanoparticles, Nanocomposites and Interfaces
    University of Massachusetts Amherst ScholarWorks@UMass Amherst Doctoral Dissertations Dissertations and Theses November 2017 POLYORGANOSILOXANES: MOLECULAR NANOPARTICLES, NANOCOMPOSITES AND INTERFACES Daniel H. Flagg University of Massachusetts Amherst Follow this and additional works at: https://scholarworks.umass.edu/dissertations_2 Part of the Materials Chemistry Commons, Polymer and Organic Materials Commons, and the Polymer Chemistry Commons Recommended Citation Flagg, Daniel H., "POLYORGANOSILOXANES: MOLECULAR NANOPARTICLES, NANOCOMPOSITES AND INTERFACES" (2017). Doctoral Dissertations. 1080. https://doi.org/10.7275/10575940.0 https://scholarworks.umass.edu/dissertations_2/1080 This Open Access Dissertation is brought to you for free and open access by the Dissertations and Theses at ScholarWorks@UMass Amherst. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of ScholarWorks@UMass Amherst. For more information, please contact [email protected]. POLYORGANOSILOXANES: MOLECULAR NANOPARTICLES, NANOCOMPOSITES AND INTERFACES A Dissertation Presented by Daniel H. Flagg Submitted to the Graduate School of the University of Massachusetts in partial fulfillment of the degree requirements for the degree of DOCTOR OF PHILOSOPHY September 2017 Polymer Science and Engineering © Copyright by Daniel H. Flagg 2017 All Rights Reserved POLYORGANOSILOXANES: MOLECULAR NANOPARTICLES, NANOCOMPOSITES AND INTERFACES A Dissertation Presented by Daniel H. Flagg Approved as to style and content by: Thomas J. McCarthy, Chair E. Bryan Coughlin, Member John Klier, Member E. Bryan Coughlin, Head, PS&E To John Null ACKNOWLEDGEMENTS There are countless individuals that I need to thank and acknowledge for getting me to where I am today. I could not have done it alone and would be a much different person if it were not for the support of my advisors, friends and family.
    [Show full text]
  • Synthesis, Recycling, and Modification of Thermoset Silicone Resins Via Fluoride Ion Catalyzed Rearrangement
    Synthesis, Recycling, and Modification of Thermoset Silicone Resins via Fluoride Ion Catalyzed Rearrangement by David James Krug III A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy (Macromolecular Science and Engineering) in The University of Michigan 2019 Doctoral Committee: Professor Richard M. Laine, Chair Professor Nicholas A. Kotov Associate Professor Kenichi Kuroda Professor Richard E. Robertson David James Krug III [email protected] ORCID iD: 0000-0003-1584-7872 © David James Krug III 2019 Dedication This dissertation is dedicated to my parents who made everything possible and to my wife who made everything worthwhile Everything I am, I owe to them ii Acknowledgements I could not have embarked on, let alone finished, this dissertation without the help of many wonderful people. First, I would like to thank my advisor, Professor Richard M. Laine, for his guidance, mentorship, and the many opportunities he has given to me over the years. I am also grateful for the support of my committee members Professor Nicholas A. Kotov, Professor Kenichi Kuroda, and Professor Richard E. Robertson. I would also like to thank all past and present members of the Laine Group. In particular, Dr. Michael Z. Asuncion, Dr. Jose Azurdia, Dr. Julien C. Marchal, and Dr. Santy Sulaiman for their direction and patience when I was an undergraduate researcher. And Dr. Eongyu Yi and Dr. Joseph C. Furgal for their support during graduate school. A special thanks to the Macromolecular Science and Engineering Department and the program coordinators over my tenure: Nonna Hamilton, Adam Mael, and Julie Pollak I thank Continental Structural Plastics (CSP) for their financial support of this work.
    [Show full text]
  • Synthesis of Pendant Epoxy Functional Polydimethyl Siloxane for Modification of Diglycidyl Ether of Bis-Phenol A
    Available online at http://www.urpjournals.com Advances in Polymer Science and Technology: An International Journal Universal Research Publications. All rights reserved Original Article Synthesis of pendant epoxy functional polydimethyl siloxane for modification of Diglycidyl Ether of Bis-phenol A Jenish Paul1, 2, A. Benny Cherian2, K.P.Unnikrishnan2 and Eby Thomas Thachil1 1- Polymer Science &Rubber Technology, Cochin university of science & Technology,Kochi- 22 2- Chemistry Department, Union Christian College, Aluva-5 Received 22 December 2011; accepted 30 December 2011 Abstract In this study, pendant epoxy functional poly dimethyl siloxanes were synthesized by the hydrosilylation reaction of pendant silyl hydride functional polydimethyl siloxane with allyl glycidyl ether. The hydrosilylation reaction was characterized by spectroscopic techniques. Samples of pendant epoxy functional poly dimethyl siloxanes and pendant silyl hydride functional polydimethyl siloxane were blended with commercial epoxy resin, diglycidyl ether of bis-phenol A, at various ratios using a polyamine as curing agent. The results show that the addition of functionalised poly dimethyl siloxanes increases the flexibility of the cross linked network and also the thermal stability and water resistance. © 2011 Universal Research Publications. All rights reserved Key words: DGEBA; resin; polysiloxanes; hydrosilylation; blending. 1. Introduction functionalise them. One of the major processes used to Epoxy resin exhibits many desirable properties, such as functionalize polysiloxanes is hydrosilylation of high strength and modulus, excellent chemical and solvent polyhydridosiloxanes [12]. resistance, good thermal and electrical properties and 1.2. Hydrosilylation outstanding adhesion to various substrates, and easy process Hydrosilanes react with compound containing carbon- ability under various conditions [1-5]. Epoxy resins are also carbon multiple bonds when catalyzed by transition metal widely used as molding compounds and encapsulation of complexes.
    [Show full text]
  • Article in Press
    ARTICLE IN PRESS Prog. Polym. Sci. xx (2004) xxx–xxx www.elsevier.com/locate/ppolysci Oligo- and polysilo xanes Yoshimoto Abe*, Takahiro Gunji Department of Pure and Applied Chemistry, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan Received 14 January 2003; revised 5 August 2003; accepted 21 August 2003 Abstract The article reviews the work on the synthesis, properties, and structure of curious oligo- and polysiloxanes which have been done mainly by the authors, referring the related papers. So far as oligosiloxanes, the topic is especially focused on sila- functional siloxanes as the building block for the synthesis of ladder or cube oligosiloxanes, while the another is the polysiloxanes derived from silicic acid and trimethoxysilanes RSi(OMe)3 which are able to form fibers and flexible free- standing films. The review also refers to the new routes for the selective synthesis of sila-functional oligosiloxanes in addition to the reaction control based on the relative reactivity of sila-functional groups. Finally, the application of polysiloxanes as the precursors to ceramics, high performance coatings, and interlayer low dielectric materials are described. q 2003 Elsevier Ltd. All rights reserved. Keywords: Sila-functional oligosiloxanes; New synthetic routes; Siloxanenols; Cube; Ladder; Polysilicic acid esters; Partially silylated silicic acids; Polysilsesquioxanes; Spinnablility; Flexible free-standing films; Ceramic precursor; Coatings; Interlayer low dielectrics Contents 1. Introduction ................................................................... 000 2. Commercially available sila-functional oligosiloxanes . ................................. 000 3. Formation of siloxanes ........................................................... 000 3.1. Various oligo- and polysiloxanes ............................................... 000 3.2. Reactivity of sila-functional groups.............................................. 000 3.3. Siloxane bond formation ....................................................
    [Show full text]
  • United States Patent (19) 11) Patent Number: 4,552,973 Feldner Et Al
    United States Patent (19) 11) Patent Number: 4,552,973 Feldner et al. (45) Date of Patent: Nov. 12, 1985 54 PROCESS FOR THE PREPARATION OF 2,647,912 8/1953 Barry et al. ......................... 556/469 DMETHYLDCHLOROSLANE 2,717,257 9/1955 Bluestein ............................. 556/469 (75. Inventors: Kurt Feldner; Wolfgang Grape, both 3,384,652 5/1968 Hamilton ............................ 556/469 of Cologne, Fed. Rep. of Germany 4,477,631 5/1984 Faure et al. ......................... 556/469 Primary Examiner-Paul F. Shaver 73 Assignee: Bayer Aktiengesellschaft, Attorney, Agent, or Firm-Sprung, Horn, Kramer & Leverkusen, Fed. Rep. of Germany Woods (21) Appl. No.: 713,501 57 ABSTRACT 22 Filed: Mar. 19, 1985 A process for the preparation of dimethyldichlorosilane (30) Foreign Application Priority Data from the low-boiling and high-boiling by-products of the direct synthesis of methylchlorosilane, comprising Mar. 23, 1984 (DE) Fed. Rep. of Germany ....... 3410644 reacting methyltrichlorosilane simultaneously with the 51) Int. Cl." ................................................ C07F 7/12 low-boiling components having a high content of 52 U.S.C. .................................................... 556/469 methyl groups and with the high-boiling non-cleavable 58 Field of Search ......................................... 556/469 components, in the presence of a catalyst, at a tempera 56) References Cited ture between about 250 C. and 400 C. and under a U.S. PATENT DOCUMENTS pressure of up to 100 bar. 2,647,136 7/1953 Sauer ................................... 556/469 4 Claims, No Drawings 4,552,973 1. 2 minum chloride which, however, is converted to the PROCESS FOR THE PREPARATION OF known catalyst AlCl3 by hydrogen chloride gas fed DIMETHYTLDICHLOROSLANE simultaneously into the reaction mixture.
    [Show full text]
  • University of California Riverside
    UNIVERSITY OF CALIFORNIA RIVERSIDE Thermal Decomposition of Molecules Relevant to Combustion and Chemical Vapor Deposition by Flash Pyrolysis Time-of-Flight Mass Spectrometry A Dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Chemistry by Jessy Mario Lemieux December 2013 Dissertation Committee: Dr. Jingsong Zhang, Chairperson Dr. Christopher Bardeen Dr. David Bocian Copyright by Jessy Mario Lemieux 2013 The Dissertation of Jessy Mario Lemieux is approved: Committee Chairperson University of California, Riverside ACKNOWLEDGMENTS Professor Jingsong Zhang Dr. Steven Chambreau Dr. Kevin Weber Paul Jones Jeff Lefler Mike Fournier Stan Sheldon Professor Christopher Bardeen Professor David Bocian iv DEDICATION This work is dedicated to my parents who taught me the value of curiosity and learning and have always been there for me. v ABSTRACT OF THE DISSERTATION Thermal Decomposition of Molecules Relevant to Combustion and Chemical Vapor Deposition by Flash Pyrolysis Time-of-Flight Mass Spectrometry by Jessy Mario Lemieux Doctor of Philosophy, Graduate Program in Chemistry University of California, Riverside, December 2013 Dr. Jingsong Zhang, Chairperson Flash pyrolysis coupled with vacuum-ultraviolet photoionization time-of-flight mass spectrometry was used to study the thermal decomposition mechanisms of molecules relevant to fuel combustion and the chemical vapor deposition (CVD) of SiGe, SiC, and GeC. For combustion research, the thermal decomposition of benzyl radical, n- alkanes CnH2n+2 (n = 5-8 and 10), 1-butyl radical, and 1-pentyl radical was performed. Benzyl was confirmed to decompose primarily by ejection of H atom after significant isomerization with loss of methyl observed as a minor decomposition pathway.
    [Show full text]
  • Comparing PPG Polysiloxane Coatings and Traditional Coating Systems
    Comparing PPG Polysiloxane Coatings and Traditional Coating Systems INTRODUCTION The last two decades have seen continuous This document examines the chemistry behind AND EXECUTIVE improvement in the performance and aesthetic PSX 700 and PSX 700SG coatings, and explains SUMMARY versatility of polysiloxane coatings. Recently, PPG why they offer superior long-term economic and achieved a significant technological advance with environmental performance compared to traditional the launch of PSX® 700SG, a new semi-gloss (SG) epoxy/urethane and epoxy/silicone-alkyd coating polysiloxane coating developed for applications systems. where the ultra-high solids content, long-term weatherability and performance of standard polysiloxane coatings are desired, but the inherent high gloss of the coating is not. PSX 700 PSX 700SG is the latest advance in the PSX 700 Since their introduction two decades ago, poly- COATINGS line of polysiloxane coatings by PPG. It offers siloxane coatings have continued to grow in both TECHNOLOGY all the performance and aesthetic advantages of development and application. Like urethanes and earlier PSX 700 coatings, but with a new propri- alkyds, they are recognized as a distinct category etary formulation that tempers the high-gloss of products within the coatings industry and, appearance of earlier-generation products. according to listings in a major industry trade magazine, the number of polysiloxane coatings “PSX 700SG is the latest The origins of the PSX 700 product line can be manufacturer tripled between 2000 and 2004. traced to 1994 when Ameron International, which advance in the PSX 700 line of was acquired by PPG in 2006, introduced the Even more importantly, polysiloxanes are now a polysiloxane coatings by PPG.” first polysiloxane coatings to the protective and preferred coating system for numerous industrial, marine coatings market.
    [Show full text]