Chlorine In Organic Compounds Research Articles

Direct Investigation of Covalently Bound Chlorine in Organic Compounds by Solid‐State 35Cl NMR Spectroscopy and Exact Spectral Line‐Shape Simulations

Simuliert: Die chemischen Verschiebungen und quadrupolaren Asymmetrieparameter, die mithilfe von Festphasen-35Cl-NMR-Spektroskopie erhalten werden, können zur Art der Cl-C-Bindung (siehe Bild) und der Kristallpackungsumgebung von Cl-Atomen in kovalenter Bindung an C-Atome in Beziehung gesetzt werden. Eine Methode für die exakte Berechnung der NMR-Spektren wurde entwickelt und für die Analyse von sieben verschiedenen Verbindungen genutzt.

Direct Investigation of Covalently Bound Chlorine in Organic Compounds by Solid‐State 35Cl NMR Spectroscopy and Exact Spectral Line‐Shape Simulations

35/37Cl NMR spectroscopy studies of organic systems are very rare, with only a few neat liquids having been studied.1 The lack of chlorine NMR spectroscopy data may be explained by the fact that 35Cl and 37Cl are quadrupolar (spin I=3/2) and low-frequency isotopes. The quadrupole moments of the chlorine nuclei couple with the electric field gradient (EFG) tensor at the nuclei; this phenomenon is known as the quadrupolar interaction (QI). The quadrupolar coupling constant, CQ, and the quadrupolar asymmetry parameter, ηQ, describe the magnitude and asymmetry of the QI. In solution, one of the consequences of the QI is fast relaxation, which means that the 35/37Cl NMR signals for covalently bound chlorines are very broad and are of low intensity.1 For these reasons, chemically distinct chlorine sites are very difficult to distinguish with solution NMR spectroscopy. However, in the solid state, nuclear spin relaxation is typically slower, thus enabling higher quality 35Cl NMR spectra to be collected, at least in principle. Unfortunately, the magnitude of the QI for covalently bound chlorines is very large because of the substantial, anisotropic EFG at the Cl atom, owing mainly to its electronic configuration when it forms a chlorine–carbon bond. Conventional wisdom is that such chlorine sites cannot be studied in powders by solid-state NMR spectroscopy as the central transition (CT; mI=1/2↔−1/2) can span tens of megahertz in typical commercially available magnetic fields. For this reason, only ionic chlorides2 and inorganic chlorides3 have been studied, as the EFG at these chlorides is often an order of magnitude smaller than at covalently bound chlorine atoms in organic molecules. The bonding environments for these types of chlorine atoms are substantially different from the environments in those chloride-containing molecules that have been studied previously.2, 3 A partial 35Cl NMR spectrum for hexachlorophene has been briefly mentioned in the literature.4 On the other hand, most of the interesting chlorine chemistry occurs when Cl is covalently bound to a carbon atom, where the chlorine atom often acts as a leaving group. Chlorine atoms are also important in many organic pharmaceuticals as well as in crystal design applications where they can form halogen bonds.5 Recent studies show that covalently bound chlorine is also important in biological chemistry where, for example, the tryptophan 7-halogenase was found to selectively chlorinate tryptophan moieties.6

Sonication of aqueous solutions of chlorobenzene

Sonication at two frequencies (20 and 900 kHz) was carried out on dilute (220 ppm) aqueous solutions of chlorobenzene. The formation of chloride ions was followed using ion chromatography. The solutions became more colored with time; the absorbance maximum was around 270 nm. Some of the compounds remaining in the solution could be identified; they were chlorinated phenols, chloronaphthalene, mono and dichlorobiphenyls, etc. At the same acoustic power, the rate of chloride formation with 20 kHz ultrasound was greater when a probe with a larger tip area was used, but significantly less than the rate with 900 kHz. The use of ultrasound for conversion of chlorine in organic compounds in water to chloride can thus be performed more efficiently using a higher frequency and with a lower intensity (power per area). There is, however, a possibility that the toxicity of the aqueous solution is increased by such treatment.

Determination of Organic Chlorine by Aluminium Monochloride Molecular Absorption Spectrometry Using Lead Atomic Line

Abstract The present study was conducted to investigate the molecular absorption by AlCl in a carbon rod furnace for determination of chlorine in organic compounds, by using the lead atomic line at 261.418 nm emitted from a Pb-hollow cathode lamp. A deuterium lamp was used for the simultaneous background correction. The method enables rapid and accurate determination of trace chlorine in varying organic samples with good precision. The method was tested on different organic chloro-coumpounds and α-pinene products.

Spectral changes in the chlorine K.ALPHA. and K.BETA. emission spectra of organic chlorine compounds.

The chemical shifts and profile changes in the chlorine Kα and Kβ X-ray emission spectra from solid organic chlorine compounds were measured with a two-crystal X-ray spectrometer. The chlorine Kα1 peaks shifted successively to higher energies with increasing electronegativity of the atom bonding to the chlorine from H to S, C and N atom. Similar tendency was found in the chemical shifts of the chlorine Kα4 satellite and Kβ1 peaks. Most of the organic chlorine compounds studied here exhibited the chlorine Kβ1 peak in the higher energy region than that of sodium chloride. The Kβ profiles of chlorine in organic compounds revealed much more complicated structures with the high and low energy satellites. The high energy satellite Kβx was observed for chlorine bonded directly to benzene ring and N atom. These spectral changes might be used to estimate the chemical bonding states of chlorine in a variety of solid organic samples.

Sequential potentiometric microdetermination of chloride and phosphate and its application to the determination of phosphorus and chlorine in organic compounds

Orthophosphate has been determined at the micro level in the presence of chloride by argentimetric potentiometric titration. Chloride is titrated first, at pH 3 in water—propan-2-ol (1:1 v/v), and phosphate in the same solution, buffered at pH 8.5–9.0. Under these conditions, the titration error from partial co-precipitation of silver oxide near the equivalence point is minimized. A procedure for performing the titration with an automatic apparatus is described. The method has been applied to the determination of phosphorus and chlorine in the same organic compound after mineralization by the Schöniger method.

Collaborative Study of Microanalytical Determination of Bromine and Chlorine by Oxygen Flask Combustion

Abstract Twenty-six collaborators participated in the study of a specific method using oxygen flask combustion followed by mercurimetric titration of the ionic halide. With the exception of 3 collaborators, all obtained good results for bromine, although a fourth collaborator obtained borderline results. Including data from all collaborators gave: mean, 36.90%; mean–theory, -0.43%; standard deviation, 0.31; and standard deviation of the means, 1.59. Omitting results of 3 collaborators, the figures become: 37.36%, +0.03%, 0.20, and 0.20, respectively. Omitting results of 4 collaborators, the values become: 37.33%, 0.00%, 0.18, and 0.15, respectively. Similar results were obtained for chlorine. The results from all collaborators gave: mean, 20.76%; mean – theory, -0.14%; standard deviation, 0.18; and standard deviation of the means, 0.48. Omitting results of 3 collaborators (the same as those for bromine), the values are : 20.89%, -0.01%, 0.14, and 0.12, respectively. Omitting the results of a fourth collaborator was not considered necessary, because the results for chlorine were borderline, and including them still gave a good overall picture. The method was adopted as official first action as an alternative to the Carius method for the determination of bromine and chlorine in organic compounds.

Rapid method for the microdetermination of chlorine in organic compounds involving combustion and automatic acidimetric coulometry

A method is described for the quantitative microdetermination of chlorine in the absence of any other halogen and sulphur. The sample (2.5–5 mg) is instantaneously mineralized in a stream of moist oxygen (60 ml/minute) inside an “Ingram” chamber at 1000 °C with a view favoring the hydrochloric acid formation rather than the chlorine one. Hydrochloric acid and chlorine are quantitatively swept into the cathodic compartment of the cell of a coulometric electrolyzer by a dry oxygen stream (400 ml/minute) which flows through the apparatus. Chlorine is reduced into hydrochloric acid by hydrogen peroxide contained in the cathodic compartment, and total hydrochloric acid is automatically titrated by coulometric acidimetry. Interfering nitrogen-acidic-combustion compounds are decomposed and retained before the coulometric cell. Carbon dioxyde is swept by bubbling oxygen out of the absorbing solution the pH of which has an appropriate value (pH = 5). The duration of a single determination within a series is 12–13 minutes. The precision of the method is the classical one.

Non-destructive determination of chlorine in organic compounds by neutron-capture gamma-ray measurement, using an isotopic neutron source

Neutron-capture γ-ray activation analysis was investigated using a 300 mCi Am−Be neutron source. Prominent photopeaks available for the analysis were observed in several high-sensitivity elements, e.g. 0.477 MeV for boron, 0.336 MeV for samarium, 0.559 for cadmium, 0.230 MeV for cobalt, 0.370 MeV for mercury, and 0.518 MeV and 0.792 MeV for chlorine. As a practical application of the method, determinations of the chlorine contents of various organic compounds were carried out, and it is shown that Cl contents of 5–50 w/v% can be determined in this way with an experimental error of less than 5%.

Iodometric microdetermination of phosphorus, sulfur and chlorine in organic compounds

A method is presented for the determination of phosphorus, sulfur and chlorine in organic compounds in absence of nitrogen by iodometry. The titration is carried out in 50% acetone solution in order to eliminate the interference of hydrogen peroxide.

Exchange of halogen by chlorine in organic compounds using mercuric chloride

1. We have improved the method of replacing iodine by chlorine in aliphatic compounds using mercuric chloride. 2. We have shown the usefulness of this method for dichloroallyl and trichloromethyl mercury organic compounds.

Note on the microdetermination of chlorine in organic compounds

The importance of using more than one method of analysis is shown by the results obtained on two compounds, both of which have structural points of similarity. Chlorine values obtained by the gravimetric Carius method were low, but those obtained by the gravimetric Pregl catalytic combustion and the Schöniger combustion methods were in agreement with the theoretical values.

The semi-micro determination of fluorine and chlorine in organic compounds. Part V. Details of the preparation of the biphenyl-sodium-dimethoxyethane complex

The semi-micro determination of fluorine and chlorine in organic compounds. Part V. Details of the preparation of the biphenyl-sodium-dimethoxyethane complex

Simultaneous determination of sulphur and chlorine in organic compounds

A method for the simultaneous determination of sulphur and chlorine on the same sample of an organic compound following a Schoniger flask combustion (or some other oxygen combustion procedure) is described. This is possible by combining the barium perchlorate titration of sulphate, using Thorin as indicator, with the mercurimetric titration of chloride using diphenylcarbazone as indicator. The micro-determination of sulphur using the former titration procedure is described fairly fully; the microdetermination of chlorine using the latter titration procedure has already been fully dealt with, and description is limited to its application to this double determination.

Determination of chlorine in organic compounds with coulometric titration

クーロン滴定法を有機元素分析へ応用することを目的として,有機化合物中塩素の定量を行なった.有機化合物の分解には迅速という見地から,Schönigerのフラスコ燃焼法,もしくは液体アンモニア中に溶解し,金属ナトリウムで分解する方法のいずれかを用いた.分解後銀イオンを用いる外部発生クーロン滴定法を応用して塩素を定量し,良好な結果を得た.分解操作を含めて分析に要した時間はフラスコ燃焼法では約30分,液体アンモニア-金属ナトリウム法では約20分であった.

Rapid micromethods of elemental analysis. I. Determination of chlorine in organic compounds

A rapid and accurate method for the determination of chlorine in organic compounds has been developed. The sample is decomposed by a simplified Schöniger oxygen flask combustion and the liberated chloride ion is determined by coulometric titration with electrolytically generated silver ion. The mean deviation on samples containing 22.45 and 12.81% chlorine was ±0.085 and ±0.060%, respectively. The method requires 3–5 mg. of sample and may be applied to smaller samples, when necessary, by decreasing the generation current. The procedure is rapid: an analyst can complete 20–25 samples a day with ease. Several methods of equivalence point detection are critically evaluated. Amperometric detection proved unreliable, while potentiometric detection using a calomel reference electrode and a silver-indicating electrode proved to be the most satisfactory.

Spectrophotometric method for the determination of chlorine in organic compounds: A semimicro- and micromethod

A rapid semimicro and micro method for the determination of chlorine in organic compounds is described. Use is made of an oxygen flask combustion technique. The chlorine ions produced in the process of combustion are reacted with mercuric chloranilate to produce strongly colored chloranilic acid which is measured spectrophotometrically. Materials which have been successfully determined include those containing 0.1% to 50% chlorine. Sulfur, nitrogen, and phosphorus do not interfere.

Microassay of chlorine in organic compounds by combustion in an empty tube: M. Vecera and J. Bulusek, Chem. listy, 52, 1526-36 (1958)

Microassay of chlorine in organic compounds by combustion in an empty tube: M. Vecera and J. Bulusek, Chem. listy, 52, 1526-36 (1958)

Analysis of Organic Compounds by Flame Spectrometry. I. Determination of Chlorine in Organic Compounds by Band Spectra of Cuprous Chloride

Abstract Examinations were made on the band spectrum of cuprous chloride based on the Beilstein’s reaction in oxy-hydrogen flame. Determination of chlorine in organic chlorine compounds was attempted by using dimethylformamide containing copper as a solvent and a band peak of 435.4 mμ of cuprous chloride. In order to decrease the effect of C2-Swan band that is produced on combustion of organic compounds, and to increase the sensitivity of cuprous chloride band spectrum, combustion gas was maintained at high oxygen pressure; 1.76 kg./cm2 (25 1b./in2 gauge), and low hydrogen pressure ; 1st, 0.035 kg./cm2 (0.5 1b./in2 gauge), 2nd, 10 cm. water column. γ-BHC was used as the standard and determination was carried out on 11 kinds of organic chlorine compounds, and good results were obtained with samples other than liquid, metal salts, and hydrochlorides. The determinable range for chlorine is 0.005∼3.1 m concentration.

The semi-micro determination of fluorine and chlorine in organic compounds. Part III. The decomposition of fluoro and chlorofluoro compounds by the diphenyl-sodium-dimethoxyethane complex

Download options Please wait... Article information DOI https://doi.org/10.1039/AN9598400245 Article type Paper Download Citation Analyst, 1959,84, 245-247 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions The semi-micro determination of fluorine and chlorine in organic compounds. Part III. The decomposition of fluoro and chlorofluoro compounds by the diphenyl-sodium-dimethoxyethane complex P. Johncock, W. K. R. Musgrave and A. Wiper, Analyst, 1959, 84, 245 DOI: 10.1039/AN9598400245 To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author P. Johncock W. K. R. Musgrave A. Wiper