Chemistry: electrical and wave energy – Processes and products
Patent
1985-02-06
1988-10-18
Richman, Barry S.
Chemistry: electrical and wave energy
Processes and products
204405, 436124, 436126, 436177, G01N 2744
Patent
active
047785705
DESCRIPTION:
BRIEF SUMMARY
The invention relates to a process of determining the concentration of halogen in organic samples, for example in chemical wastes. The total of organic halogen is indicated by the expression of TOX, in which X represents a chlorine, bromine, or iodine atom.
Organic halogen compounds, and especially the chlorine and/or bromine containing compounds, are important constituents of chemical wastes. Handling, use and draining of these substances are subject to strict rules in view of the possible danger of these substances to man and environment. Consequently, a reliable analytical method is indispensable.
The analytical instruments now available for determining the concentration of halogen in organic samples use various methods to determine the concentration. However, because these methods are based on certain physico-chemical properties of the halo-organic compounds which a number of the halo-organic compounds do not possess, it is not certain that a particular method will allow the determination of the total concentration of the organic halogen.
Presently, three analytical methods are being used, often in combination. In the first method, volatile halo-organic compounds are removed from a solution by bubbling an inert gas, for example nitrogen, through the solution and feeding the gas containing the halo-organic compounds in an oven where they are converted to hydrogen halide. Subsequently, the halide can be analysed coulometrically. The amount so determined is designated as volatile organic halogen (VOX).
In the second method an extraction is used, for example with diisopropyl ether, diisobutyl ketone or methylisobutyl ketone. The halide concentration in the extract is also determined coulometrically after destruction and oxidation in an oven. This amount is designated as extractable organic halogen (EOX). In a third method, the sample is passed through a column of active carbon and the halogen content of the active carbon is then determined by controlled combustion (pyrolizing the halo-organic compounds adsorbed to the active carbon) in an oven. The resulting hydrogen halide is analyzed coulometrically, as in the preceding methods. This amount is designated as adsorbable organic halogen (AOX).
It will be clear that a number of halo-organic compounds, such as those compounds which are non-volatile, non-extractable or non-adsorbable, cannot be analyzed with these methods. Illustrative in this respect is the 1980 leaflet of the Dohrman, Envirotech "Total organic halide analyzer", in which the yields for the adsorption to active carbon are very clearly governed by the polarity of the halo-organic compound. Thus, in case of 1-chlorodecane a yield of 100%, for chloroethanol a yield of 20% and for chloroacetic acid a yield of 0% is found. In view of this, the following equation will hold generally: TOX.noteq.VOX+EOX+AOX. This discrepancy is larger when the sample contains higher amounts of substances which cannot be removed by said methods. This is the situation for substances which cannot be removed by prior art methods (stripping, extraction, adsorption) due to the fact that they are polar and/or ionogenic. Such compounds cannot be extracted by a solvent less polar than water, and cannot be adsorbed onto active carbon.
Examples of halogenic compounds which cannot be analyzed with these methods are the halophenols, the haloanilines, the halocarboxylic acids, the sulphonated haloaromates etc. As, in practical cases, the nature of the halo-organic compounds is often not known, a determination of VOX, EOX and AOX gives a result which has an unknown relation to TOX. Therefore, the concentration of organic halogen found by this method will be too low in many cases. Additionally, the concentration of organic halogen found by this method will be too high in certain cases. This is the case when an organic substance is present as a salt with halide ion as counter ion, and this substance, on extraction, passes into the organic solvent so that its analysis will include the halide ions. Examples of these substances are quate
REFERENCES:
patent: 3413199 (1968-11-01), Morrow, Jr.
patent: 3876514 (1975-04-01), Baizer
patent: 4028201 (1977-06-01), Tyssee
patent: 4072584 (1978-02-01), Cipris et al.
patent: 4160802 (1979-07-01), White et al.
patent: 4539083 (1985-09-01), Samejima et al.
Farwell et al., Anal. Chem., vol. 47, No. 6, Amer. Chem. Soc. (Washington, D.C.), 1975, pp. 895-903.
Peeters et al., J. Org. Chem., vol. 40, No. 3, Amer. Chem. Soc., (Wash., D.C.), 1975, pp. 312-318.
Tingane, Electroanalytical Chemistry, 2nd Ed., Interscience Publishers, Inc., (New York), 1958, pp. 373-380.
Indirect Polarographic Microdetermination of Fluorine in Fluro-Organic Compounds After Oxygen-Flask Combustion, Y. A. Gawargious, A. Besada, B. N. Faltaoos, Analytical Chemistry, vol. 47, No. 3, pp. 502-505, Mar. 1975, American Chemical Society, Books and Journals Division, Washington, D.C. 20036.
Hill Jr. Robert J.
Nederlandse Centrale Organisatie Voor Toegepast-Natuurwetenschap
Richman Barry S.
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