SILICONES USED for FOOD CONTACT APPLICATIONS Version 1 Œ 10.06.2004

Total Page:16

File Type:pdf, Size:1020Kb

SILICONES USED for FOOD CONTACT APPLICATIONS Version 1 Œ 10.06.2004 PUBLIC HEALTH COMMITTEE COMMITTEE OF EXPERTS ON MATERIALS COMING INTO CONTACT WITH FOOD POLICY STATEMENT CONCERNING SILICONES USED FOR FOOD CONTACT APPLICATIONS Version 1 œ 10.06.2004 NOTE TO THE READER The following documents are part of the Policy statement concerning silicones used for food contact applications: Resolution ResAP (2004) 5 on silicones to be used for food contact applications Technical document No. 1 œ List of substances to be used in the manufacture of silicones used for food contact applications The documents are available on the Internet website of the Partial Agreement Division in the Social and Public Health Field: www.coe.int/soc-sp 2 TABLE OF CONTENTS Page Resolution ResAP (2004) 5 on silicones to be used for food contact applications ……………………………………………………………………….……. 4 Technical document No. 1 œ List of substances to be used in the manufacture of silicones used for food contact applications ……………………… 8 3 RESOLUTION RESAP (2004) 5 ON SILICONES USED FOR FOOD CONTACT APPLICATIONS 4 RESOLUTION RESAP (2004) 5 ON SILICONES USED FOR FOOD CONTACT APPLICATIONS (adopted by the Committee of Ministers on 1st December 2004 at the 907 th meeting of the Ministers‘ Deputies) (superseding Resolution AP AP (99) 3) The Committee of Ministers, in its composition restricted to the Representatives of Austria, Belgium, Cyprus, Denmark, Finland, France, Germany, Ireland, Italy, Luxembourg, The Netherlands, Norway, Portugal, Slovenia, Spain, Sweden, Switzerland and the United Kingdom, member states of the Partial Agreement in the Social and Public Health Field, Recalling Resolution (59) 23 of 16 November 1959, concerning the extension of the activities of the Council of Europe in the social and cultural fields; Having regard to Resolution (96) 35 of 2 October 1996, whereby it revised the structures of the Partial Agreement and resolved to continue, on the basis of revised rules replacing those set out in Resolution (59) 23, the activities hitherto carried out and developed by virtue of that resolution; these being aimed in particular at: a. raising the level of health protection of consumers in its widest application, including constant contribution to harmonising œ in the field of products having a direct or indirect impact on the human food chain as well as in the field of pesticides, pharmaceuticals and cosmetics œ legislation, regulations and practices governing, on the one hand, quality, efficiency and safety controls for products and, on the other hand, the safe use of toxic or noxious products; b. integrating people with disabilities into the community; defining œ and contributing to its implementation at European level œ a model coherent policy for people with disabilities, which takes account simultaneously of the principles of full citizenship and independent living; contributing to the elimination of barriers to integration, whatever their nature, whether psychological, educational, family-related, cultural, social, professional, financial or architectural; Having regard to the action carried out for several years for the purposes of harmonising legislation in the public health field and, in particular, with regard to materials and articles intended to come into contact with foodstuffs; Considering that silicones used for food contact applications may, by reason of the migration of their components to the foodstuffs, pose a risk to human health; Taking the view that each member state, faced with the need to introduce regulations governing this matter, would find it beneficial to harmonise such regulations at European level, Recommends to the governments of the member states of the Partial Agreement in the social and public health field to take into account in their national laws and regulations on silicones used for food contact applications the principles set out hereafter. 5 APPENDIX 1 TO RESOLUTION RESAP (2004) 5 1. Definition Silicones constitute a group of polymeric chemical substances and preparations, all containing polysiloxanes. Polysiloxanes are characterised by Si-O-Si and Si-C bonds. They are prepared from chlorosilanes which are subjected to hydrolysis. Polysiloxanes such as fillers, emulsifiers, solvents etc. are also covered by the definition. Furthermore, copolymers or polymer-blends of polysiloxanes with organic polymers are comprised in the term —silicones“, provided siloxane monomer units predominate by weight over each of the other monomer units present. Silicones used as food additives are not covered by the definition. 2. Description of the silicone product group Silicones include a range of products with a variety of properties and applications: 2.1. silicone elastomers: coatings, sealants, etc.; 2.2. silicone liquids: additives to plastics and coatings, release agents for moulding plastic articles, impregnating agents for textiles, etc.; 2.3. silicone pastes: lubricants for food processing machinery etc.; 2.4. silicone resins: heat-resistant coatings, release coatings in food production such as bakery, etc. 3. Specifications Silicones used for food contact applications, hereafter called silicones, should meet the following requirements: 3.1. they should not transfer their constituents to foodstuffs in quantities which could endanger human health or bring about an unacceptable change in the composition of the foodstuffs or deterioration in the organoleptic characteristics thereof; 3.2. they should be manufactured in accordance with a certified Quality Assurance System (for example, ISO 9002 or CEN 29-004) and under the conditions specified in —Technical document No. 1 œ List of substances used in the manufacture of silicones used for food contact applications “; 3.3. interactions between starting substances or between starting substances and any other substance used in the manufacturing process of silicones should not lead to the formation of compounds which pose a risk to human health; 3.4. linear siloxanes containing methyl- and phenyl- groups attached to the same silicone atom and also containing two methyl- groups attached to one silicon atom (siloxanes and silicones, Me-, Ph-, di-Me-) should not be used as starting substances, in order to prevent the formation of certain phenyl-substituted cyclic polydimethylsiloxanes; 6 3.5. the release of any substance from silicones to foodstuffs should be as low as technologically possible. The total of all substances migrating into food from silicone materials or articles should not exceed 10 mg/dm 2 of the surface area of the final material or article or 60 mg/kg of food, this being considered as the overall migration limit; 3.6. the migration limits set out in —Technical document No. 1 œ List of substances used in the manufacture of silicones used for food contact applications “ should be met; 3.7. migration tests should be conducted according to Directives 82/711/EEC, 85/572/EEC, 90/128/EEC, 93/8/EEC, 97/48/EEC and their future amendments, as appropriate, unless technically impracticable due to the nature of the material and the migration tests; 3.8. appropriate labelling for the materials or articles should be assured, if pre-washing by the user is necessary. 7 TECHNICAL DOCUMENT No. 1 LIST OF SUBSTANCES USED IN THE MANUFACTURE OF SILICONES USED FOR FOOD CONTACT APPLICATIONS Version 1 œ 10.06.2004 8 1. CLASSIFICATION SYSTEM OF SUBSTANCES TO BE USED FOR MATERIALS AND ARTICLES INTENDED TO COME INTO CONTACT WITH FOODSTUFFS General specifications List 1 - Substances approved for the use of materials and articles intended to come into contact with food 1. Substances evaluated by SCF, classified in list 0-4, and used in compliance with specific migration limits or other restrictions, if any; 2. Substances evaluated and approved by the Committee of expert on materials coming into contact with food; 3. Substances approved in Partial Agreement member states or by FDA, based on an evaluation of a toxicological dossier, which meets the present SCF criteria; 4. Substances authorised as direct food additives in compliance with specific migration limits or other restrictions; 5. The substances which have been approved by Partial Agreement member states or by FDA applying scientific evaluation criteria of the time of their approval will be listed in a Temporary Appendix to List 1. List 2 œ Substances not approved for the use of materials and articles intended to come into contact with food Substances which do not meet the criteria set for List 1 substances. Complementary specifications 1. The substances of the Temporary Appendix should be integrated in List 1 or List 2 not later than five years after adoption of the List of substances. 2. Lists 1 and List 2 will be updated in principle once a year in order to take into account newly evaluated substances, new submissions by industry or substances to be deleted. 9 2. Introduction 2.1. The lists contain the substances (starting substances, polymerisation aids and additives) to be used in the manufacture of silicones used for food contact applications and which, due to their non-reactive groups, are likely to be present in the final material or article and which may therefore be found in the overall migrate. 2.2. Precursors and other substances, which contain reactive groups and which due to their reactivity are incorporated into a solid macromolecular structure and which therefore are not likely to be found in the overall migrate, are not included in the present list, as they disappear during the manufacturing process. 2.3. As regards the list of starting substances: • the majority of substances listed are polymers with functional groups from which the polymeric macro-network is formed after reaction with cross-linking agents; • many of the polymers are groups of products with their assigned CAS registration number, as for example: - siloxanes and silicones, di-Me, me-vinyl (CAS No. 67762-94-1) are a group comprising linear polymeric molecules with a wide variation in chain length and content of vinyl groups; - silsesquioxanes, Me-Ph (CAS No. 67763-03-5) and siloxanes and silicones, di-Me, polymers with Me-Ph-silsesquioxanes (CAS No. 68440- 81-3) each describe a group of branched polymeric siloxanes with wide variations in molecular weight, degree of branching and ratio Me : Ph.
Recommended publications
  • Summary Tables of Calculated and Experimental Parameters Of
    Summary Tables of Calculated and Experimental Parameters of Diatomic, Triatomic, Organic, Silicon, Boron, Aluminum and Organometallic Molecules, Exemplary Results on Condensed Matter Physics, One-Through Twenty-Electron Atoms, Excited States of Helium, g Factor, and Fundamental Particle Masses The closed-form derivations from Maxwell's equations given in The Grand Unified Theory of Classical Physics posted at http://www.blacklightpower.com/theory/bookdownload.shtml contain fundamental constants only. The nature of the chemical bond is given in Chapters 12 through 15. The atoms are solved exactly in Chapters 1, 7, and 10. The excited states of helium are solved exactly in Chapter 9. The electron g factor and relations between fundamental particles are given in Chapter 1 and Chapters 36, 37 and 38. Tables summarizing the results of the calculated experimental parameters of 800 exemplary solved molecules follow. The closed-form derivations of these molecules can be found in The Grand Theory of Classical Physics posted at http://www.blacklightpower.com/theory/bookdownload.shtml Chapters 15–17, as well as Silicon in Chapter 20, Boron in Chapter 22, and Aluminum and Organometallics in Chapter 23. Condensed matter physics based on first principles with analytical solutions of (i) of the geometrical parameters and energies of the hydrogen bond of H2O in the ice and steam phases, and of H2O and NH3; (ii) analytical solutions of the geometrical parameters and interplane van der Waals cohesive energy of graphite; (iii) analytical solutions of the geometrical parameters and interatomic van der Waals cohesive energy of liquid helium and solid neon, argon, krypton, and xenon are given in Chapter 16.
    [Show full text]
  • EPA Handbook: Optical and Remote Sensing for Measurement and Monitoring of Emissions Flux of Gases and Particulate Matter
    EPA Handbook: Optical and Remote Sensing for Measurement and Monitoring of Emissions Flux of Gases and Particulate Matter EPA 454/B-18-008 August 2018 EPA Handbook: Optical and Remote Sensing for Measurement and Monitoring of Emissions Flux of Gases and Particulate Matter U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Air Quality Assessment Division Research Triangle Park, NC EPA Handbook: Optical and Remote Sensing for Measurement and Monitoring of Emissions Flux of Gases and Particulate Matter 9/1/2018 Informational Document This informational document describes the emerging technologies that can measure and/or identify pollutants using state of the science techniques Forward Optical Remote Sensing (ORS) technologies have been available since the late 1980s. In the early days of this technology, there were many who saw the potential of these new instruments for environmental measurements and how this technology could be integrated into emissions and ambient air monitoring for the measurement of flux. However, the monitoring community did not embrace ORS as quickly as anticipated. Several factors contributing to delayed ORS use were: • Cost: The cost of these instruments made it prohibitive to purchase, operate and maintain. • Utility: Since these instruments were perceived as “black boxes.” Many instrument specialists were wary of how they worked and how the instruments generated the values. • Ease of use: Many of the early instruments required a well-trained spectroscopist who would have to spend a large amount of time to setup, operate, collect, validate and verify the data. • Data Utilization: Results from path integrated units were different from point source data which presented challenges for data use and interpretation.
    [Show full text]
  • A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres P
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by St Andrews Research Repository The Astrophysical Journal Supplement Series, 224:9 (33pp), 2016 May doi:10.3847/0067-0049/224/1/9 © 2016. The American Astronomical Society. All rights reserved. A CHEMICAL KINETICS NETWORK FOR LIGHTNING AND LIFE IN PLANETARY ATMOSPHERES P. B. Rimmer and Ch Helling School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, UK; [email protected] Received 2015 June 3; accepted 2015 October 22; published 2016 May 23 ABSTRACT There are many open questions about prebiotic chemistry in both planetary and exoplanetary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life andprebiotic chemistry outside the solar system. We present an ion–neutral chemical network constructed from scratch, STAND2015, that treats hydrogen, nitrogen, carbon, and oxygen chemistry accurately within a temperature range between 100 and 30,000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. STAND2015 is successfully tested against atmospheric chemistry models for HD 209458b, Jupiter, and the present-day Earth using a simple one- dimensionalphotochemistry/diffusion code. Our results for the early Earth agree with those of Kasting for CO2,H2, CO, and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present.
    [Show full text]
  • Directed Gas Phase Formation of Silicon Dioxide and Implications for the Formation of Interstellar Silicates
    ARTICLE DOI: 10.1038/s41467-018-03172-5 OPEN Directed gas phase formation of silicon dioxide and implications for the formation of interstellar silicates Tao Yang 1,2, Aaron M. Thomas1, Beni B. Dangi1,3, Ralf I. Kaiser 1, Alexander M. Mebel 4 & Tom J. Millar 5 1234567890():,; Interstellar silicates play a key role in star formation and in the origin of solar systems, but their synthetic routes have remained largely elusive so far. Here we demonstrate in a combined crossed molecular beam and computational study that silicon dioxide (SiO2) along with silicon monoxide (SiO) can be synthesized via the reaction of the silylidyne radical (SiH) with molecular oxygen (O2) under single collision conditions. This mechanism may provide a low-temperature path—in addition to high-temperature routes to silicon oxides in circum- stellar envelopes—possibly enabling the formation and growth of silicates in the interstellar medium necessary to offset the fast silicate destruction. 1 Department of Chemistry, University of Hawai’iatMānoa, Honolulu, HI 96822, USA. 2 State Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai, 200062, China. 3 Department of Chemistry, Florida Agricultural and Mechanical University, Tallahassee, FL 32307, USA. 4 Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA. 5 Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast, Belfast, BT7 1NN, UK. Correspondence and requests for materials should be addressed to R.I.K. (email: [email protected]) or to A.M.M. (email: mebela@fiu.edu) or to T.J.M. (email: [email protected]) NATURE COMMUNICATIONS | (2018) 9:774 | DOI: 10.1038/s41467-018-03172-5 | www.nature.com/naturecommunications 1 ARTICLE NATURE COMMUNICATIONS | DOI: 10.1038/s41467-018-03172-5 — 28 + 28 + he origin of interstellar silicate grains nanoparticles ( SiO2 ), and 44 ( SiO ).
    [Show full text]
  • Gas Phase Formation of C-Sic3 Molecules in the Circumstellar Envelope of Carbon Stars
    Gas phase formation of c-SiC3 molecules in the circumstellar envelope of carbon stars Tao Yanga,b,1,2, Luke Bertelsc,1, Beni B. Dangib,3, Xiaohu Lid,e, Martin Head-Gordonc,2, and Ralf I. Kaiserb,2 aState Key Laboratory of Precision Spectroscopy, East China Normal University, Shanghai 200062, P. R. China; bDepartment of Chemistry, University of Hawai‘iatManoa, Honolulu, HI 96822; cDepartment of Chemistry, University of California, Berkeley, CA 94720; dXinjiang Astronomical Observatory, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, P. R. China; and eNational Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, P. R. China Contributed by Martin Head-Gordon, May 17, 2019 (sent for review July 20, 2018; reviewed by Piergiorgio Casavecchia and David Clary) Complex organosilicon molecules are ubiquitous in the circumstel- Modern astrochemical models propose that the very first lar envelope of the asymptotic giant branch (AGB) star IRC+10216, silicon–carbon bonds are formed in the inner envelope of the but their formation mechanisms have remained largely elusive until carbon star, which is undergoing mass loss at the rates of several − now. These processes are of fundamental importance in initiating a 10 5 solar masses per year (22, 23). Pulsations from the central chain of chemical reactions leading eventually to the formation of star may initiate shocks, which (photo)fragment the circumstellar — organosilicon molecules among them key precursors to silicon car- materials (24, 25). These nonequilibrium conditions cause tem- — bide grains in the circumstellar shell contributing critically to the peratures of 3,500 K or above (19) and lead to highly reactive galactic carbon and silicon budgets with up to 80% of the ejected metastable fragments such as electronically excited silicon atoms, materials infused into the interstellar medium.
    [Show full text]
  • Most Common Substances in Chemicals for Different Industries
    Table 14 Most common substances by industry Figures for 2009. Substances contained in more than 10 products. A substance can be omitted for secrecy reasons. Industry CAS-no Substance Number of products A01 Agriculture 7732-18-5 Water 458 6484-52-2 Nitric acid ammonium salt 77 57-55-6 1,2-Propanediol 75 64742-65-0 Distillates (petroleum), solvent-dewaxed heavy 74 paraffinic 63148-62-9 Siloxanes and Silicones, di-Me 60 57-13-6 Urea 54 67-63-0 2-Propanol 54 11138-66-2 Xanthan gum 53 7783-20-2 Sulfuric acid diammonium salt 53 7722-76-1 Phosphoric acid, monoammonium salt 52 7487-88-9 Sulfuric acid magnesium salt (1:1) 51 7447-40-7 Potassium chloride 46 56-81-5 1,2,3-Propanetriol 44 7778-80-5 Sulfuric acid dipotassium salt 43 1310-73-2 Sodium hydroxide 41 7647-14-5 Sodium chloride 41 2634-33-5 1,2-Benzisothiazol-3(2H)-one 38 1310-58-3 Potassium hydroxide 33 7757-79-1 Nitric acid potassium salt 33 7785-87-7 Manganese sulfate 32 7664-38-2 Phosphoric acid 32 72623-87-1 Lubricating oils, petroleum, C20-50, 31 hydrotreated neutral oil-based 64741-89-5 Distillates (petroleum), solvent-refined light 29 paraffinic 77-92-9 1,2,3-Propanetricarboxylic acid, 2-hydroxy- 28 8061-51-6 Lignosulfonic acid, sodium salt 28 7778-18-9 Sulfuric acid, calcium salt (1:1) 27 64-17-5 Ethanol 27 14807-96-6 Talc 26 64742-94-5 Solvent naphtha (petroleum), heavy arom. 25 68649-42-3 Phosphorodithioic acid, O,O-di-C1-14-alkyl 24 esters, zinc salts (2:1) 64-02-8 Glycine, N,N'-1,2-ethanediylbis[N- 24 (carboxymethyl)-, tetrasodium salt 64-19-7 Acetic acid 23 99-76-3 Benzoic acid,
    [Show full text]
  • Reaction Pathways Linking Chemisorption to Desorption of Methylchlorosilanes on Copper(001)
    REACTION PATHWAYS LINKING CHEMISORPTION TO DESORPTION OF METHYLCHLOROSILANES ON COPPER(001) BY JAMES LALLO A dissertation submitted to the Graduate School|New Brunswick Rutgers, The State University of New Jersey in partial fulfillment of the requirements for the degree of Doctor of Philosophy Graduate Program in Chemistry and Chemical Biology Written under the direction of Professor B.J. Hinch and approved by New Brunswick, New Jersey October, 2012 ABSTRACT OF THE DISSERTATION Reaction pathways linking chemisorption to desorption of methylchlorosilanes on copper(001) by James Lallo Dissertation Director: Professor B.J. Hinch The interactions of silane molecules with metal surfaces are pivotal in many com- mercial processes. Of particular interest is the commercial \Direct Process," in which methyl chloride (CH3Cl) is exposed to silicon, in the presence of a copper catalyst and other promoters, producing dimethyldichlorosilane as the predominant product. Previous UHV studies have investigated the interaction of \pre-dissociated" methyl (CH3) and chlorine (Cl) with copper and copper-silicide surfaces. This thesis investi- gates the reaction mechanisms of \pre-associated" methylchlorosilanes ((CH3)xClySiHz, x+y+z=4) adsorbed on a copper(001) surface. The goal was to develop an understand- ing of the intermediates and transfer processes involved for dissociative adsorption and subsequent desorption of these molecules. Only molecules containing at least one Si- H bond were observed to undergo chemisorption. It was found that dimethylsilane (CH3)2SiH2 and methylsilane (CH3)SiH3 exhibit ligand transfer on the copper sur- face, leading to the desorption of trimethylsilane (CH3)3SiH, in both cases. The sug- gested intermediates present after adsorption of methylsilane were methylsilyl CH3SiH2, methysilylene CH3SiH and methylsilylidyne CH3Si.
    [Show full text]
  • Sih; X2Π) with Dimethylacetylene (CH3CCCH3; X1a1g
    Article pubs.acs.org/JPCA Formation of the 2,3-Dimethyl-1-silacycloprop-2-enylidene Molecule via the Crossed Beam Reaction of the Silylidyne Radical (SiH; X2Π) 1 with Dimethylacetylene (CH3CCCH3;XA1g) Tao Yang, Aaron M. Thomas, Beni B. Dangi, and Ralf I. Kaiser* Department of Chemistry, University of Hawai’i at Manoa, Honolulu, Hawaii 96822, United States Mei-Hung Wu, Bing-Jian Sun, and Agnes H. H. Chang* Department of Chemistry, National Dong Hwa University, Shoufeng, Hualien 974, Taiwan *S Supporting Information ABSTRACT: We carried out crossed molecular beam experiments and electronic structure calculations to unravel the chemical dynamics of the 2Π reaction of the silylidyne(-d1) radical (SiH/SiD; X ) with dimethyla- 1 cetylene (CH3CCCH3;XA1g). The chemical dynamics were indirect and initiated by the barrierless addition of the silylidyne radical to both carbon atoms of dimethylacetylene forming a cyclic collision complex 2,3-dimethyl-1-silacyclopropenyl. This complex underwent unimolecular decomposition by atomic hydrogen loss from the silicon atom via a loose exit transition state to form the novel 2,3-dimethyl-1-silacycloprop-2- enylidene isomer in an overall exoergic reaction (experimentally: −29 ± 21 kJ mol−1; computationally: −10 ± 8 kJ mol−1). An evaluation of the scattering dynamics of silylidyne with alkynes indicates that in each system, the silylidyne radical adds barrierlessly to one or to both carbon atoms of the acetylene moiety, yielding an acyclic or a cyclic collision complex, which can also be accessed via cyclization of the acyclic structures. The cyclic intermediate portrays the central decomposing complex, which fragments via hydrogen loss almost perpendicularly to the rotational plane of the decomposing complex exclusively from the silylidyne moiety via a loose exit transition state in overall weakly exoergic reaction leading to ((di)methyl-substituted) 1-silacycloprop-2-enylidenes (−1to−13 kJ mol−1 computationally; −12 ± 11 to −29 ± 21 kJ mol−1 experimentally).
    [Show full text]
  • The Synthesis and Characterization of Binuclear Zirconocene Complexes and Their Study As Initiators in the Polymerization of M
    END-GROUP FUNCTIONALIZATION OF ANIONICALLY SYNTHESIZED POLYMERS VIA HYDROSILATION REACTIONS A Dissertation Presented to The Graduate Faculty of The University of Akron In Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy Hoon Kim May, 2006 END-GROUP FUNCTIONALIZATION OF ANIONICALLY SYNTHESIZED POLYMERS VIA HYDROSILATION REACTIONS Hoon Kim Dissertation Approved: Accepted: Advisor Department Chair Dr. Roderic P. Quirk Dr. Mark D. Foster Committee Member Dean of the College Dr. Joseph P. Kennedy Dr. Frank N. Kelley Committee Member Dean of the Graduate School Dr. William Brittain Dr. George R. Newkome Committee Member Date Dr. Coleen Pugh Committee Member Dr. Chrys Wesdemiotis ii ABSTRACT One of the unique features of living, alkyllithium-initiated, anionic polymerization is the ability to produce a stable carbanionic chain end after complete monomer consumption, which can be followed by reaction with electrophiles to form various end- functionalized polymers. Although a variety of functional polymers have been synthesized in the last few decades, each specific functionalization has had to be designed and optimized individually. Consequently, the development of general functionalization methodologies has drawn recent interest. However, even these general functionalization methods require the use of protecting groups, and the complexity in synthetic routes and the thermal/moisture instability of many protected functional agents have restricted their practical application. This thesis describes a new, general functionalization methodology, combining well-defined, living anionic polymerization with efficient and highly selective, platinum-catalyzed hydrosilation reactions with functionalized alkenes. Well-defined, Si-H functionalized polymers (P-SiH) have been synthesized by sec- butyllithium-initiated, living anionic polymerization in benzene followed by termination with dimethylchlorosilane.
    [Show full text]
  • A Review of Organosilanes in Organic Chemistry
    A Review of Organosilanes in Organic Chemistry • Silyl Protecting and Derivatisation Reagents • Organosilanes as Reducing Agents • Silanes in Cross-coupling Chemistry • Allylsilanes Used to Stabilize α-Carbanions and β-Carbocations INTRODUCTION Organosilanes have varied uses in organic chemistry from the most frequently employed protecting groups to intermediates in organic synthesis. The Acros Organics portfolio of organosilanes is continuously expanding to meet your chemistry needs. In this brochure you will find an overview of four of the most important applications of organosilanes: • Silyl Protecting and Derivatisation Reagents 1, 2 • Organosilanes as Reducing Agents 3 • Silanes in Cross-coupling Chemistry 4 • Allylsilanes Used to Stabilize α-Carbanions and β-Carbocations4 Silyl Protecting and Derivatisation Reagents Silicon protecting groups are probably the most frequently employed of all protecting groups, and modern natural product synthesis is inconceivable without them.5 Silylating agents are mostly used to protect alcohols and phenols, but have also found application in the protection of amines, carboxylic acids, amides, thiols and alkynes. By varying the substituents attached to silicon, the steric and electronic characteristics of the protecting group can be finely tuned, allowing a wide variety of both reaction and deprotection conditions. The leaving group also plays an important role in the reactivity and use of silylating reagents. Whilst chlorotrimethylsilane [product code: 42643] liberates hydrogen chloride on reaction,
    [Show full text]
  • Hazardous Substances (Chemicals) Transfer Notice 2006
    16551655 OF THURSDAY, 22 JUNE 2006 WELLINGTON: WEDNESDAY, 28 JUNE 2006 — ISSUE NO. 72 ENVIRONMENTAL RISK MANAGEMENT AUTHORITY HAZARDOUS SUBSTANCES (CHEMICALS) TRANSFER NOTICE 2006 PURSUANT TO THE HAZARDOUS SUBSTANCES AND NEW ORGANISMS ACT 1996 1656 NEW ZEALAND GAZETTE, No. 72 28 JUNE 2006 Hazardous Substances and New Organisms Act 1996 Hazardous Substances (Chemicals) Transfer Notice 2006 Pursuant to section 160A of the Hazardous Substances and New Organisms Act 1996 (in this notice referred to as the Act), the Environmental Risk Management Authority gives the following notice. Contents 1 Title 2 Commencement 3 Interpretation 4 Deemed assessment and approval 5 Deemed hazard classification 6 Application of controls and changes to controls 7 Other obligations and restrictions 8 Exposure limits Schedule 1 List of substances to be transferred Schedule 2 Changes to controls Schedule 3 New controls Schedule 4 Transitional controls ______________________________ 1 Title This notice is the Hazardous Substances (Chemicals) Transfer Notice 2006. 2 Commencement This notice comes into force on 1 July 2006. 3 Interpretation In this notice, unless the context otherwise requires,— (a) words and phrases have the meanings given to them in the Act and in regulations made under the Act; and (b) the following words and phrases have the following meanings: 28 JUNE 2006 NEW ZEALAND GAZETTE, No. 72 1657 manufacture has the meaning given to it in the Act, and for the avoidance of doubt includes formulation of other hazardous substances pesticide includes but
    [Show full text]
  • Arxiv:1510.07052V1 [Astro-Ph.EP] 23 Oct 2015 99 Lae Ta.20,Adrfrne Therein)
    A Chemical Kinetics Network for Lightning and Life in Planetary Atmospheres P. B. Rimmer1 and Ch Helling School of Physics and Astronomy, University of St Andrews, St Andrews, KY16 9SS, United Kingdom ABSTRACT There are many open questions about prebiotic chemistry in both planetary and exoplane- tary environments. The increasing number of known exoplanets and other ultra-cool, substellar objects has propelled the desire to detect life and prebiotic chemistry outside the solar system. We present an ion-neutral chemical network constructed from scratch, Stand2015, that treats hydrogen, nitrogen, carbon and oxygen chemistry accurately within a temperature range between 100 K and 30000 K. Formation pathways for glycine and other organic molecules are included. The network is complete up to H6C2N2O3. Stand2015 is successfully tested against atmo- spheric chemistry models for HD209458b, Jupiter and the present-day Earth using a simple 1D photochemistry/diffusion code. Our results for the early Earth agree with those of Kasting (1993) for CO2, H2, CO and O2, but do not agree for water and atomic oxygen. We use the network to simulate an experiment where varied chemical initial conditions are irradiated by UV light. The result from our simulation is that more glycine is produced when more ammonia and methane is present. Very little glycine is produced in the absence of any molecular nitrogen and oxygen. This suggests that production of glycine is inhibited if a gas is too strongly reducing. Possible applications and limitations of the chemical kinetics network are also discussed. Subject headings: astrobiology — atmospheric effects — molecular processes — planetary systems 1. Introduction The input energy source and the initial chem- istry have been varied across these different ex- The potential connection between a focused periments.
    [Show full text]