Decomposition Of Chloroform Research Articles

Photocatalytic decomposition of chloroform in a fully irradiated heterogeneous photoreactor using titanium oxide particulate suspensions

The photocatalytic decomposition of HCCl 3 was studied in a fully irradiated photoreactor (FIP) by varying the concentrations of (a) chloroform, (b) dissolved oxygen and (c) titania, as well as (d) the local volumetric rate of energy absorption (LVREA). Fully irradiated conditions are achievable when all the particles along the light path ‘see the photons’. In order to compute the VREA (average value of the LVREA), the radiative transfer equation (RTE) was applied to the reactor and solved using a simplified radiation model. Model parameters, i.e., optical properties, as well as the boundary condition for the RTE were obtained experimentally. Initial rate data of the chloroform decomposition showed that, within the studied range of process variables and under fully irradiated conditions: (1) The reaction rate is of first order with respect to [HCCl 3], zero order with respect to [O 2] and about one-half-order with respect to the LVREA inside the reactor and (2): The effects due to catalyst concentration are fully accounted for within the LVREA dependence.

Surface chemistry and extreme pressure lubricant additive properties of chloroform on iron

The growth kinetics and composition of films formed by the thermal decomposition of chloroform are very similar to those for methylene chloride reported previously [P.V. Kotvis et al., Wear 147 (1991) 401; 153 (1992) 305; Appl. Surf. Sci. 40 (1989) 213; Langmuir 9 (1993) 467], both depositing films that consist of an iron halide and incorporating carbon. Raman spectroscopy suggests that less carbon is incorporated into the layer grown from chloroform, an effect that is proposed to reflect the initial carbon : chlorine ratio in the precursor reactants. The tribological properties measured using a pin and V-block apparatus from the seizure load as a function of the additive concentration are very similar in both cases, showing an initial increase in seizure load up to additive concentrations of ≈ 2 wt% of chlorine and remaining constant thereafter, the main difference being that the saturation seizure load is higher when using chloroform than when methylene chloride is the additive. This effect is explained since the interfacial coefficient of friction of films grown from chloroform are lower than those from methylene chloride so that, for a particular applied load, the interfacial temperature is lower in the former case. Since the seizure load in the plateau region (at high additive concentrations) corresponds to the load at which the interface reaches the melting point of FeCl 2, this temperature is attained at a higher load with CHCl 3 than CH 2Cl 2. It is possible that the amount of carbon incorporated into the iron halide anti-seizure film affects the resulting coefficient of friction.

Chloroform Pyrolysis: Experiment and Detailed Reaction Model

Abstract Chloroform was used as a model chlorocarbon system with high Cl/H ratio to investigate the thermal decomposition processes of chlorocarbons in pyrolytic reaction environments. The thermal decomposition of 1.0% chloroform in argon bath gas was studied to determine important chlorocarbon reaction pathways in pyrolysis. The reactions were studied in tubular flow reactors at a total pressure of 1 atm with residence times of 0.3-2.0 sec in the temperature range 535-800°C. A detailed kinetic reaction mechanism to describe the important features of products and reagent loss was developed. The mechanism is based on thermochemical principles and accurately describes the overall reaction process. We determine that the primary decomposition reaction pathway for chloroform is: CHCl3 → HCl +: CCl2 in the above temperature regime by combined experiment and modeling studies. High pressure limit rate constants obtained in this work for initially important decomposition of chloroform were determined as: A(1/sec.)...

Palladium-catalyzed alkoxycarbonylation of vinyl and arylorganotins under high pressure

Summary The palladium-catalyzed cross coupling reaction between substituted aryl-and vinyltins and chloroformates under high pressure is reported. It proceeds smoothly to provide esters in excellent yields under mild conditions. High pressure prevents the decomposition of chloroformates observed under normal pressure.

Oxidative pyrolysis of CH2Cl2, CHCl3, and CCl4‐I: Incineration implications

AbstractThe oxidative pyrolysis of methylene chloride, chloroform, and carbon tetrachloride has been investigated using a micro‐bore, fused silica, tubular flow reactor operating under laminar flow conditions coupled to in‐line GC‐MS detection. Data were obtained over the temperature range 573–1273 K for the following conditions: chlorocarbon/oxygen equivalence ratios of 3.0, chlorocarbon concentrations of 2.7 ± 0.1 × 10−5 mols/L, gas‐phase residence times of 2.0 s, and reactor pressures of 1.15 ± 0.05 atm. The parent stability (defined by the temperature required for 99% destruction) was evaluated as: Chemically activated recombination of chlorinated C1 radicals are proposed as important pathways to chlorinated ethane and olefin products. The most significant finding from analysis of product distributions containing ≥2 carbon atoms was the observation of ca. 1 mol% yields of higher‐molecular‐weight perchlorinated aromatic species from the decomposition of chloroform and carbon tetrachloride. Implications with respect to the controlled high‐temperature incineration of these chlorinated methanes are briefly discussed.

A feasibility study of dechlorination of chloroform in water by ultrasound in the presence of hydrogen peroxide

Abstract Dechlorination of chloroform in water with ultrasound in combination with hydrogen peroxide has been studied. It is believed that the decomposition of chloroform is accomplished by free radical reaction. The experimental results indicate that the optimal hydrogen peroxide concentration has a molar ratio of H2O2:CHCl3 = 50:1. The addition of ferrous ions (20 mg L−1) into solution will increase the efficiency while the addition of methanol will decrease the efficiency. Under optimal conditions the efficiency in removal of chloroform can reach 94%. A kinetic plot shows that the overall reaction appears to be a first order reaction.

ChemInform Abstract: FUNCTIONALIZED ENAMINES. XXIX. SOLVOLYTIC TRANSFORMATIONS OF 2‐METHYLISOQUINOLIN‐1‐ONE DICHLOROCARBENE ADDUCT. SYNTHESIS OF BENZAZEPINONES

AbstractDas bei der basenkatalysierten Zers. von Chloroform erhaltene Dichlorcarben reagiert mit (I) zum Addukt (II), das mit H2O den Aldehyd (III) ergibt.

Functionalized enamines XXIX. Solvolytic transformations of 2‐methylisoquinolin‐1‐one dichlorocarbene adduct. Synthesis of benzazepinones

AbstractDichlorocarbene, generated from base‐catalysed decomposition of chloroform, adds to the double bond of 2‐methylisoquinolin‐1‐one (1), to give the 1:1 adduct (2). The latter adduct reacts with water to give E‐3‐(formylmethylene)‐2‐methylisoindolinone (3a). Refluxing of 2 in alcohols yields alkoxybenzazepin‐1‐ones. Upon heating (of 2) in dimethoxyethane and subsequent reduction with lithium borohydride, 4‐chloro‐2‐methyl‐1H‐2,3‐dihydro‐2‐benzazepinone (10) was obtained as the main product. Mechanisms for the formation of these products are discussed.

A Shock Tube Study of the Decomposition Mechanism of Chloroform in the Presence of Deuterium or Methane

Abstract Chloroform was pyrolyzed in the absence and in the presence of one of three additives—D2, CH4, and CD4, over the temperature range of 1000–1200 K in a single-pulse shock tube. The main products of the decomposition of chloroform by itself were tetrachloroethylene and hydrogen chloride. On the other hand, tetrachloroethylene, trichloroethylene, dichloromethane, and hydrogen chloride were the major products in the presence of D2, while in the chloroform–methane systems they were tetrachloroethylene, trichloroethylene, 1,1-dichloroethylene, vinyl chloride, ethane, and hydrogen chloride. From the deuterium distribution of the products, as determined by mass spectrometry, it is found that the hydrogen atoms of trichloroethylene and 1,1-dichloroethylene mainly came from chloroform and methane respectively, while the hydrogen atoms of vinyl chloride came from both chloroform and methane. The change in the product distribution resulting from the addition of deuterium or methane and the hydrogen isotopic distribution suggest that the mechanism is composed of Cl atom elimination in the initiation step and successive reactions involving “hot” molecule reactions. The hydrogen isotopic distribution of vinyl chloride may indicate that the three-centered hydrogen elimination (αα) process competes with the four-centered (αβ) process in the decomposition of “hot” 1,1-dichloroethane.

Role of the triplet state in the benzene-sensitized decomposition of chloroform

A study has been made of the effect of increasing chloroform pressure on benzene and biacetyl emission under various conditions. No quenching of benzene fluorescence by chloroform is observed when excitation is by 2570 Å radiation, whether or not biacetyl is present. On the other hand, quenching of the sensitized biacetyl phosphorescence is pronounced. However, it is demonstrated that chloroform does not quench biacetyl phosphorescence when excitation occurs at 3660 Å, from which it can be concluded that chloroform preferentially accepts energy from the benzene triplet rather than the excited singlet. Therefore it is probably the triplet which is responsible for the benzene-photosensitized decomposition of chloroform previously reported.

Kinetics of the γ-Ray-Induced Decomposition of Chloroform1

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTKinetics of the γ-Ray-Induced Decomposition of Chloroform1Horst R. Werner and Richard F. FirestoneCite this: J. Phys. Chem. 1965, 69, 3, 840–849Publication Date (Print):March 1, 1965Publication History Published online1 May 2002Published inissue 1 March 1965https://doi.org/10.1021/j100887a023RIGHTS & PERMISSIONSArticle Views86Altmetric-Citations22LEARN 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 (1021 KB) Get e-Alerts

Thermal decomposition of chloroform in the presence of olefins

AbstractThe gas‐phase decomposition of chloroform at 400‐500°C in the presence of an alkene leads to a chlorodiene and hydrogen chloride.Evidence is presented that the primary step is the decomposition of chloroform to dichlorocarbene, which adds to the alkene; the resulting dichlorocyclopropane rearranges, with loss of hydrogen chloride, to a chlorodiene.

The Thermal Decomposition of Chloroform. I. Products1a

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTThe Thermal Decomposition of Chloroform. I. Products1aGeorge P. Semeluk and Richard B. BernsteinCite this: J. Am. Chem. Soc. 1954, 76, 14, 3793–3796Publication Date (Print):July 1, 1954Publication History Published online1 May 2002Published inissue 1 July 1954https://doi.org/10.1021/ja01643a060RIGHTS & PERMISSIONSArticle Views737Altmetric-Citations38LEARN 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 (474 KB) Get e-Alerts Get e-Alerts

Use of perbenzoic acid in analysis of unsaturated compounds. I. Preparation and stability of solutions of perbenzoic acid

AbstractThe preparation of perbenzoic acid has been investigated in a n attempt to obtain standard solutions of perbenzoic acid suitable for the amlyszk of unsaturated compounds. Some modifiations of the procedure given by Braun for the preparation of a solution of perbenzoic acid in a n organic solvent are recommended. A study has been made of the stability of solutions of perbenzoic acid in chloroform and in benzene. Benzene or benzene‐chloroform mixtures are recommended as solvents for perbenzoic acid. Chloroform solutions of perbenzoic acid which do not contain inhibitors for decomposition have been found to be definitely undesirable in analytical work because perbenzoic acid catalyzes the decomposition of chloroform by oxygen. construction Finance Corporation, in connection with the Government Synthetic Rubber Program.

Influence of Sensitisers on Chemical Reactions produced by Gamma Radiation

ATTENTION was first directed to the above subject during the course of an investigation on the decomposition of chloroform by radiation from radon. Chloroform is decomposed with liberation of chlorine which slowly disappears with formation of hydrochloric acid as a secondary product. The decomposition was measured by estimating the chlorine set free. Certain discrepancies were obtained in the results which were largely explained when it was found that the apparent rate of decomposition was greatly influenced by the presence of the products formed. This was shown by irradiating for a second time the chloroform containing small quantities of products from the first irradiation. It has been demonstrated by others that traces of moisture considerably increase the decomposition of chloroform by X-radiation.

The decomposition of chloroform by radiations from radon

The decomposition of chloroform by radiations from radon