Reaction Of Methyl Chloride Research Articles

Computational Insights into the CH3 Cl+OH Chemical Reaction Dynamics at the Air-Water Interface.

The reaction of methyl chloride with the hydroxyl radical OH is an important process in the troposphere. The kinetics of this reaction has been thoroughly studied in the gas phase, both experimentally and theoretically, but little is known about the effect of water on this reaction. In particular, investigating the reaction mechanism at the air-water interface is key in order to better understand the role of cloud water droplets and aerosols on the overall oxidation capacity of the troposphere. In this work, we have implemented a "rare event" approach combined to QM/MM (quantum mechanics and molecular mechanics) molecular dynamics simulations to investigate the dynamics of the H-abstraction reaction CH3 Cl+OH→CH2 Cl+H2 O at the air-water interface. For comparison, high-level ab initio calculations for the reaction mechanism in the gas phase are also reported and accurate kinetic constants at different temperatures are provided.

DFT studies of conversion of methyl chloride and three substituted chloromethyl tetrahydrofuran derivatives during reaction with trimethylamine

B3LYP/6-31+G** level computations were performed for the formation of four trimethylammonium salts in the reaction of methyl chloride (1a), (S)-1,4-andydro-5-chloro-2,3,5-trideoxypentitol (2a), (2S,5S)-2,5-andydro-6-chloro-1,3,4,6-tetradeoxyhexitol (3a) and methyl 5-chloro-2,3,5-trideoxy-β-D-pentofuranoside (4a) with trimethylamine. All the structures were fully optimized in the gas phase, in chloroform and water. In addition, B3LYP/6-311++G** and MPW1K/6-31+G** level calculations were carried out to estimate activation barrier heights in the gas phase. A detailed description of all stationary points is presented, and the conformational behavior of the THF ring is discussed. B3LYP and MPW1K activation barriers indicate the reaction between methyl chloride and trimethylamine to be the fastest, whereas reaction 4 is the slowest one, both in the gas phase and in solvents. THF ring conformation changes were observed for reactions 2 and 3 along the reaction pathway, whereas it was almost unchanged for reaction 4, in the gas phase. In the case of reactions 2 and 3, different shapes of the THF ring were found for the transition state geometry in the gas phase and in water. The 5 E→E 4 and 3 E→E 5 conformational changes were observed for reactions 2 and 3, respectively. Graphical abstractReactions of the formation of quaternary ammonium salts

Midland Silicones Memories

One of the world’s most significant silicone manufacturing sites is in Barry, South Wales, owned by Dow Corning Corporation. Silicones have been produced at this site since 1952 but for the first two decades the companywas known asMidland Silicones Ltd. (not to be confused with the Midland Silicon Company L.L.C.). Midland Silicones was my entrance to the fascinating world of organosiliconmaterials and I hope that these indulgent reminiscences will trigger memories for some readers and acquaint others with this bygone joint venture. The two partners in the new company were Dow Corning Corporation of Midland, Michigan, USA and Albright and Wilson with headquarters at Oldbury in the West Midlands of England. Given these geographical realities one supposes that little time was devoted to deciding the name of the new company. To the American joint owners it was usually referred to as Midsil but to my colleagues at least, it was either Midland Silicones in full or shortened to MS, never Midsil. For the other partner, Albright and Wilson, the move into silicones was not particularly adventurous from an elemental viewpoint. Their operation was based on the chemistry of phosphorus. Silicon and phosphorus are adjacent members of the periodic table. Despite this elemental proximity Albright and Wilson’s contribution to the new venture was financial and managerial not technical. Much of the necessary capital came from the Oldbury firm as did the initial senior staff, including John Hughes, the head man at Barry throughout the Midland Silicones era. For several years such aspects as professional hiring were dealt with through the Albright and Wilson organization. Dow Corning with its almost ten years experience with silicones provided the technical knowledge and expertise as well as many materials and intermediates. The so-called Muller-Rochow direct process reaction lies at the heart of the silicone industry and the Dow Corning experience with this process was key to its establishment in Barry. It is still the standard technology for industrial preparation of organosilicon compounds, but even today there are few such primary reactors because of the complexity of the process and its high capital requirements. The process is based on the reaction of methyl chloride with silicon metal in a fluidized bed. Only Wacker Chemie AG and Midland Silicones Ltd. had this capability in Europe in the 1950s. The Barry site had originally been developed in the Second World War to extract magnesium from sea water. Given that the UK’s longest river, the Severn, and several other rivers make the Bristol Channel at Barry rather less salty than it is further west, this location decision does make one wonder. That venture was called Ocean Salts, a name that persisted for quite a few years among some local inhabitants after the establishment of Midland Silicones. I would like to think there are a few residents who still refer to the present site by the name I first knew it by although forty years on I realize this is rather unlikely. When I first saw the Barry site I was struck by its large concrete bowls. How clever, I thought; catchment basins for containing spilled silicone fluids in an emergency, little knowing I was looking at the settling bowls used in the old magnesium extraction process. The larger ponds behind the factory, possibly another remnant of Ocean Salts, were home to nesting swans and other wildlife. To Dow Corning’s credit, expansion at this site has not impaired this coexistence with Guest Editorial: Michael J. Owen

Moving least-squares enhanced Shepard interpolation for the fast marching and string methods

The number of the potential energy calculations required by the quadratic string method (QSM), and the fast marching method (FMM) is significantly reduced by using Shepard interpolation, with a moving least squares to fit the higher-order derivatives of the potential. The derivatives of the potential are fitted up to fifth order. With an error estimate for the interpolated values, this moving least squares enhanced Shepard interpolation scheme drastically reduces the number of potential energy calculations in FMM, often by up 80%. Fitting up through the highest order tested here (fifth order) gave the best results for all grid spacings. For QSM, using enhanced Shepard interpolation gave slightly better results than using the usual second order approximate, damped Broyden-Fletcher-Goldfarb-Shanno updated Hessian to approximate the surface. To test these methods we examined two analytic potentials, the rotational dihedral potential of alanine dipeptide and the S(N)2 reaction of methyl chloride with fluoride.

Periodic Trends in the Agostic Interaction in Zirconium and Hafnium Methylidene Hydride Halide Complexes

The reactions of methyl chloride and bromide with laser-ablated Zr and Hf atoms during deposition in excess Ne, Ar, or Kr are investigated, and the products are examined by matrix IR spectroscopy and density functional theory calculations. The methylidene complexes, [CH2=MHX] (M = Zr and Hf, X = Cl and Br), are formed along with the methyl metal halide complexes, [CH3-MX]. The amounts of both types of complexes increase upon photolysis and in the early stages of annealing. Two sets of methylidene absorptions observed in Ar and Kr matrices form a persistent photoreversible system. The most stable C1 and slightly higher energy planar structures of the methylidene complex in the singlet ground state trapped in the matrix reproduce the characteristics of the two sets of absorptions. Agostic distortion of the methylidene complexes decreases in the order Ti, Zr, Hf and increases in the order F, Cl, and Br; the C=Zr and Zr-H stretching frequencies increase, and the bonds become shorter. This observation favors the characterization of the agostic interaction as a reorganization of charge.

Mathematical Models for Direct Reaction of Methyl Chloride With Silicon in Fluidized Bed Reactor

Methyl chlorosilanes are important raw materials for the production of polyalkylsiloxanes, the basic ingredient of silicone oils and silicone rubbers. One of the main methods for the commercial production of methyl chlorosilanes, known as direct process, involves a reaction between elemental silicon (Si) and methyl chloride (MeCl). The principal product is dimethyldichlorosilane, which is used to form the polydimethylsiloranes. The aim of this work is to predict a mathematical models in which it shows the behavior of the reaction. We predict four models, these models take in consideration the reaction kinetic the physical, chemical, and design equation of fluidized bed reactor. The equations shows the conversion of MeCl as function of temperature and time, conversion of silicone as function of time, particle diameter as function of time. We have compared the result from these models with practical result from international papers. And it shows good agreement.

Dissociative adsorption of methyl chloride on Si(001) studied by scanning tunneling microscopy

Chemical reactions of methyl chloride (CH3Cl) on a clean Si(001) surface at approximately 300 K are studied by means of scanning tunneling microscopy (STM) under ultra-high-vacuum conditions. The features appearing in the STM images are identified with the possible products of dissociated CH3 and Cl, and their distribution is also evaluated as well as the development of their distribution with increasing CH(3)Cl doses. The amount of Cl atoms found on the surface is approximately twice as large as that of the CH3 molecules. This leads to the conclusion that dissociative adsorption of CH3Cl on Si occurs in different processes: CH3Cl(precursor) --> CH3(ad) + Cl(ad) and CH3Cl(precursor) --> CH3(gas) + Cl(ad).

Formation of CH3TiX, CH2TiHX, and (CH3)2TiX2 by Reaction of Methyl Chloride and Bromide with Laser-Ablated Titanium Atoms: Photoreversible α-Hydrogen Migration

The simple methylidene (CH2=TiHX) and Grignard-type (CH3TiX) complexes are produced by reaction of methyl chloride and bromide with laser-ablated Ti atoms and isolated in a solid Ar matrix, and they form a persistent photoreversible system via alpha-hydrogen migration between the carbon and titanium atoms. The Grignard-type product is transformed to the methylidene complex upon UV (240 nm < lambda < 380 nm) irradiation and vice versa with visible (lambda > 530 nm) irradiation. More stable dimethyl dihalide complexes [(CH3)2TiX2] are also identified, whose relative concentration increases upon annealing and at high methyl halide concentration. The reaction products are identified with three different groups of absorptions on the basis of the behaviors upon broadband photolysis and annealing, and the vibrational characteristics are in a good agreement with DFT computation results.

Gas phase reactions of NH 2Cl with anionic nucleophiles: nucleophilic substitution at neutral nitrogen

Reactions of chloramine, NH 2Cl, with HO −, RO − (R = CH 3, CH 3CH 2, CH 3CH 2CH 2, C 6H 5CH 2, CF 3CH 2), F −, HS −, and Cl − have been studied in the gas phase using the selected ion flow tube technique. Nucleophilic substitution ( S N 2) at nitrogen to form Cl − has been observed for all the nucleophiles. The reactions are faster than the corresponding S N 2 reactions of methyl chloride; the chloramine reactions take place at nearly every collision when the reaction is exothermic. The thermoneutral identity S N 2 reaction of NH 2Cl with Cl −, which occurs approximately once in every 100 collisions, is more than two orders of magnitude faster than the analogous reaction of CH 3Cl. The significantly enhanced S N 2 reactivity of NH 2Cl is consistent with a previous theoretical prediction that the barrier height for the S N 2 identity reaction at nitrogen is negative relative to the energy of the reactants, whereas this barrier height for reaction at carbon is positive. Competitive proton abstraction to form NHCl − has also been observed with more highly basic anions (HO −, CH 3O −, and CH 3CH 2O −), and this is the major reaction channel for HO − and CH 3O −. Acidity bracketing determines the heat of deprotonation of NH 2Cl as 374.4 ± 3.0 kcal mol −1.

Infrared spectroscopic study of adsorption and reactions of methyl chloride on acidic, neutral and basic zeolites

Infrared (IR) spectroscopic investigations were performed of the adsorption and surface reactions of CH 3 Cl over acidic, basic and neutral zeolite catalysts. In each case, the spectral changes reflected the appearance of the Fermi resonance phenomenon. The resonance parameters determined pointed to a decreasing extent of resonance in consequence of the adsorption. No influence of the acidity of the adsorbents was observed. The formation and consumption of HCl and OH groups were established at elevated temperatures. The reactions assumed to have occurred are described and explained.

Infrared spectroscopic study of adsorption and reactions of methyl chloride on acidic, neutral and basic zeolites

Infrared (IR) spectroscopic investigations were performed of the adsorption and surface reactions of CH 3Cl over acidic, basic and neutral zeolite catalysts. In each case, the spectral changes reflected the appearance of the Fermi resonance phenomenon. The resonance parameters determined pointed to a decreasing extent of resonance in consequence of the adsorption. No influence of the acidity of the adsorbents was observed. The formation and consumption of HCl and OH groups were established at elevated temperatures. The reactions assumed to have occurred are described and explained.

Infrared Study of the Adsorption and Reaction of MethylChloride and Methyl Iodide on Silica-Supported Pt Catalysts

The low-temperature adsorption of methyl chloride andmethyl iodide on silica-supported Pt catalysts has beeninvestigated by transmission Fourier transform infraredspectroscopy. The IR data show that methyl chloride and methyliodide dissociate at low temperatures (near 200 K) to form anadsorbed hydrocarbon fragment on the surface, identified asmethyl groups. Methyl groups are characterized by a singleinfrared absorption band near 2965 cm−1. Methyl groups reactwith hydrogen to form gas-phase methane as the sample is warmedbetween 200 and 473 K. Reaction of approximately 10 Torr ofmethyl chloride at 473 K over a Pt/SiO2catalyst shows that only20% of the methyl chloride decomposes to form gas-phase methaneand hydrogen chloride in the absence of hydrogen. However, inthe presence of an equal amount of hydrogen, all of the methylchloride is converted to methane and hydrogen chloride. Incontrast to the quantitative conversion of methyl chloride, lessthan 10% of the initial 10 Torr of methyl iodide forms methaneat 473 K and no hydrogen iodide forms in the presence or absenceof hydrogen gas. Although the activation barrier for C–Cl bonddissociation in adsorbed methyl chloride is higher than thebarrier for C–I bond dissociation in adsorbed methyl iodide, thelower energy barrier for removal of adsorbed chlorine comparedto adsorbed iodine is the cause of the higher catalytic activityof Pt/SiO2toward methyl chloride decomposition. In addition tothe thermal decomposition of CH3Cl, we have investigated thepossibility of using solar radiation for the decomposition ofCH3Cl on Pt/SiO2. The results for the photo-assisteddecomposition of CH3Cl adsorbed on Pt/SiO2are presented and discussed.

Reaction of methyl chloride with alumina surfaces: a study of the methoxy surface species by transmission infrared spectroscopy

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTReaction of methyl chloride with alumina surfaces: a study of the methoxy surface species by transmission infrared spectroscopyThomas P. Beebe Jr., J. E. Crowell, and John T. Yates Jr.Cite this: J. Phys. Chem. 1988, 92, 5, 1296–1301Publication Date (Print):March 1, 1988Publication History Published online1 May 2002Published inissue 1 March 1988https://doi.org/10.1021/j100316a056RIGHTS & PERMISSIONSArticle Views283Altmetric-Citations56LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (796 KB) Get e-Alerts

Reactions of methyl chloride and of methylene chloride at metal surfaces: II. Reactions over evaporated films of titanium and other metals

The reaction of methyl chloride and hydrogen, and of methylene chloride and hydrogen has been studied at the surface of a number of evaporated metal films in a static system. Adsorption of alkyl chloride resulted in rupture of all carbon-chlorine bonds before any carbon-hydrogen bonds were broken; thus in the reaction with deuterium, virtually no deuteroparent was formed. By the use of 13C and 35Cl it was shown that in the adsorption of methyl chloride on titanium, carbon-chlorine bond rupture was totally irreversible. Over nickel, tungsten, copper, platinum, cobalt, manganese, aluminum and silver, methane was the only hydrocarbon product. Over palladium and titanium higher hydrocarbons were formed. In the reaction of methylene chloride over titanium, polymer was also formed, and olefins were the main C 2 and C 3 products. The reaction of methyl chloride on titanium was shown to be first order in both methyl chloride and hydrogen pressures. Adsorption measurements with the alkyl chlorides on the above metals gave surface hydrogen/carbon ratios which, in most cases, suggested the average surface hydrocarbon residue to be more extensively dehydrogenated than the group in the original alkyl chloride: the extent of dehydrogenation increased with increasing temperature. The exception to this was titanium where adsorption of methyl chloride and methylene chloride gave approximately CH 3 and CH 2 surfaces residues, respectively. From the influence of hydrogen on the reaction product distribution, and from the results from reactions with deuterium it has been concluded that on palladium, chemisorbed hydrogen was directly involved in the process of product desorption, but on titanium this was not so, and inter-residue hydrogen transfer occurred in desorption. Evidence has been adduced that carbon-carbon bond formation probably occurred by reaction of an alkyl chloride molecule with a surface CH 2 group. Activation energies and frequency factors have been evaluated for the reactions of both alkyl chlorides on titanium.

Reactions of methyl chloride and of methylene chloride at metal surfaces: I. Reactions at a sodium surface

Reactions of methyl chloride and of methylene chloride have been studied at the surface of clean evaporated films of sodium in the range −78 ° to 60 °C. Reaction proceeded to give a surface tarnish layer into which was bound all of the chlorine and about half of the carbon from the reacted alkyl chloride, the balance of the carbon being returned to the gas phase as methane, ethane, and ethylene. Evidence is adduced that the surface product layer from methyl chloride and from methylene chloride can be considered as containing CH 3 − and CH 2 2−, respectively. The reaction of methyl chloride has been found to be strongly photoaccelerated by light of wavelength lying in the F-center absorption band of sodium chloride. By the use of 13C- and 35Cl-labeled material, the reactions of methyl chloride (for instance) have been interpreted in terms of reactions at the surface (i) between two CH 3 −, (ii) between CH 3 − and undissociated methyl chloride, the latter probably present as CH 3Cl −, (iii) between two CH 3Cl −. The effect of illumination is considered to be to facilitate reaction (iii) by a process analogous to M-center formation known for alkali halides. This M-center analogue forms a sterically favorable site for the required reaction.

Formation of alkyl- and aryl-chlorosilanes by the direct reaction of alkyl and aryl chlorides with silicon Communication 5. Effect of secondary processes of dichloromethylsilane breakdown on the synthesis of chloromethylsilanes

The breakdown of dichloromethylsilane on the active centers of a silicon-copper catalysis mixture is greatly retarded in presence of methyl chloride adsorbed on the same active centers. This explains the possibility of the formation of dichloromethylsilane as one of the main products of the reaction of methyl chloride with those catalysis mixtures which are most active in bringing about its breakdown.

Organische Phosphorverbindungen. XXVII Die direkte Synthese von Tetramethylphosphoniumhalogeniden

AbstractThe reaction of methyl chloride and methyl bromide with white phosphorus is studied under a variety of conditions, and the conditions giving a high yield of tetramethylphosphonium chloride and bromide are established. Thermal decomposition of [(CH3)4P]+Cl− gives (CH3)3P and CH3Cl, and alkaline decomposition of [(C4H9)3(C12H25)P]+Cl− gives C4H10 and (C4H9)2(C12H25)PO.

Organische Phosphorverbindungen VIII. Die direkte Synthese von Alkyl‐ und Aryl‐halogenphosphinen

AbstractThe reaction of methyl chloride, methyl bromide, methyl iodide, trifluoro‐methyl iodide, ethyl chloride, ethyl bromide, butyl bromide, and phenyl bromide with red phosphorus has been studied under a variety of conditions. In additon, the reaction of white phosphorus with methyl bromide and phenyl bromide is also described. The synthesis and properties of RPX2 (R = CH3, CF3, C2H5, C6H5, C6H5; X = Cl, Br, I) and R2PX (R = CH3, CF3, C6H5; X = Cl, Br) are reported. The reactions of RPX2 and R2PX With sulfur and with dimethylamine are also described.

(82)塩化メチルと珪素-銅との反応に伴なう高沸点溜分の利用に関する研究(第1報)〓,〓及び〓なる3種の型の化合物の存在について

(82)塩化メチルと珪素-銅との反応に伴なう高沸点溜分の利用に関する研究(第1報)〓,〓及び〓なる3種の型の化合物の存在について

(107)塩化メチルと珪素-銅との反応に伴なう高沸点溜分の利用に関する研究(第2報)ハロゲンによる珪素-珪素結合の切断について

(107)塩化メチルと珪素-銅との反応に伴なう高沸点溜分の利用に関する研究(第2報)ハロゲンによる珪素-珪素結合の切断について