JP2916886B2 - Method for the determination of carbonyl chloride - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to carbonyl chloride.
The present invention relates to a method capable of quantifying (phosgene) .

[0002]

2. Description of the Related Art At present, in the chemical industry manufacturing industry, various health problems due to chemical substances and the like have occurred along with the diversification of approval and permission of new substances. Therefore, while applying the Prevention Rules for Specific Chemical Substances (hereinafter abbreviated as specialization rules) in order to prevent these health disorders, the measurement of the concentration of air in the substance used, the evaluation of the measurement results, and the evaluation results It is necessary to take action based on In addition, in order to contribute to the promotion of hygiene management, while applying from photoelectric spectrophotometry to high-performance liquid chromatography (hereinafter abbreviated as HSLC),
It is also necessary to consider harmonization of work environment measurement and personal exposure measurement for evaluation of measurement results.

[0003] First, under the legal system in both the United States and Japan,
There are assessments of management categories based on A and B measurements based on the controlled concentrations notified by the Ministry of Labor of Japan and the allowable concentrations recommended by the Japan Society for Occupational Health, while the State Labor Bureau in the United States and the American Conference of Governmental Industria
l Threshold Limit Value-Ti recommended by Hygienists
me Weighted Average, TLV-Short Time Exposure Limit
And TLV-Ceiling and Occupational Safety and He
There is an assessment of personal exposure monitors based on TWA and Ceiling recommended by alth Administration, and there is DirectionRegionale du Travail et de l'Emploi in France.

In addition, there is a quality control concerning accuracy and precision in measurement and analysis while complying with the above-mentioned control density and allowable density rules. Specifically, the present inventor has already established HSLC measurement methods for ortho-tolidine, 3,3'-dichloro-4,4'-diaminodiphenylmethane, benzene, benzidine and phthalic anhydride, and has been implementing hygiene management. Was.

[0005] Further, there is a study of a measuring method for various new drug substances, and simultaneous quantification and interference caused by a matrix. More specifically, the methods for measuring potassium cyanide, hydrogen cyanide, and sodium cyanide used in electrolytic degreasing baths, copper plating baths, and zinc plating baths include a pyridine-pyrazolone method using an existing distilled water absorbing solution. And a method for quantifying a 2,3-dicyanohydroquinone derivative by an HSLC fluorescence method using a p-benzoquinone absorbing solution. As a method for measuring manganese and its compounds commonly used in mixing and molding of dry batteries, there is an atomic absorption spectrophotometry using an existing glass fiber filter, but 1- (2,4-azorilazo) -2-. It has been improved to “stopped flow photoelectric spectrophotometry” using a naphthol complex absorbing solution.

Further, as a method for measuring formaldehyde, acetaldehyde, formic acid and acetic acid used for spray coating and the like, there is an existing chromotropic acid method using distilled water. It has been improved to a chromatographic method. In addition, as a method for measuring diborane and boron trioxide used as an impurity doping gas in a Si epitaxial growth furnace, there is an HSLC method using a chromotropic acid absorbing solution, and hygiene management techniques related to the above-described measuring method are being promoted. .

For example, when quantifying carbonyl halide, for example, phosgene (COCl ₂ ) corresponding to the third category, generated by brazing or arc welding in the presence of a chlorine-based organic solvent, carbonyl fluoride is allowed to coexist. Collection with an aniline absorbing solution and quantification using hexane-pentanol solvent extraction-photoelectric spectrophotometry has been performed. However, such a method cannot cope with the diversification of carbonyl halides, making simultaneous quantification difficult.

As described above, the methods proposed so far have not been suitable methods for quantifying carbonyl chloride .

[0009]

SUMMARY OF THE INVENTION The present invention solves such a problem in the conventional quantification method, and separates carbonyl chloride , which has been difficult to simultaneously quantify, with high accuracy . It is an object to provide a separation and quantification method capable of quantification.

The present inventor has proposed that carbonyl chloride generated from a halogen-based organic solvent is reacted under specific conditions with an aqueous aniline solution to form a urea derivative, which is separated using a high performance liquid chromatograph. The inventors have found that simultaneous quantification can be performed with high accuracy, and completed the present invention.
Further, the present inventor has set forth various conditions for a method for collecting phosgene and carbonyl fluoride in an ignition combustion gas relating to a chlorine-based organic solvent used in a refrigerant for a car air conditioner, a urethane foaming agent and a cleaning agent for precision parts. Was also considered.

[0011]

DISCLOSURE OF THE INVENTION The carbonyl chloride of the present invention
The method for quantifying
Is converted to aniline under the conditions of room temperature and pH 5.7 to 7.3.
Reaction with an aqueous solution, and the product
Separation using a high performance liquid chromatograph
From the corresponding peak area,
Characterized in that the concentration of That is, the present invention
Carbonyl chloride , which is difficult to separate and quantify directly,
Quantitative collection using an aqueous aniline solution under the conditions
The concentration of carbonyl is obtained by reaction with aniline
It is calculated from the concentration of the product, and when calculating the concentration of carbonyl chloride , a special calculation formula is used.
The HSLC conditions and the formulas used for calculating the concentration of each substance will be described in detail in Examples below. In the method of the present invention, the reaction formula when phosgene and carbonyl fluoride react with aniline is shown below.

[0012]

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As described above, in the present invention, when separating and quantifying the urea derivative formed by the reaction of carbonyl chloride with aniline, it is preferable to use a water-alcohol solvent for the mobile phase. Calcium chloride with high resolution
Bonyl can be separated and quantified. In the present invention,
When the generated urea derivatives are the same, the generated inorganic anion (hydrogen halide) may be measured, or may be measured by two absorbance ratio methods. Hereinafter, embodiments of the present invention will be described.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Method for Quantifying Halogenated Carbonyls Method for Preparing Reagents An aniline ampoule was dissolved in 1N hydrochloric acid and then prepared as an aqueous aniline solution having a predetermined concentration. Then, the pH was adjusted to 8 with 0.1 N sodium hydroxide, and further adjusted to a predetermined concentration with distilled water. Also, sym-diphenyl urea [hereinafter, referred to as
DPU] was prepared by diluting a standard solution with methanol, and o-, p-chloroaniline and 2,4-dichloroaniline were diluted with methanol for qualitative purposes. The mobile phase was methanol and 0.02N hydrochloric acid (9:
Prepared in 1). Phosgene was heated in a water bath with carbon tetrachloride in a steam reactor with a condenser. Immediately after boiling,
Fuming sulfuric acid (containing about 30% of SO ₃ ) was dropped from the top of the reactor, and phosgene was automatically collected from the outlet pipe into a 1-liter tetrabac. A known amount of phosgene was collected in a 5-liter tetrabag using a 100-ml glass syringe, and diluted exactly 10-fold with dry air to obtain a standard gas.
The reagents used were all manufactured by Wako Pure Chemical Industries.

Measuring Apparatus Hitachi 638-50 was used for the high-performance liquid chromatograph. UV detector is Hitachi 635-0900 type multi-wavelength UV
It was a monitor and measured at 250 nm. In the separation column, a styrene-divinylbenzene spherical copolymer (Hitachi Gel 3013, particle size 5 μm) was subjected to a slurry method at 150 mm ×
The column was self-packed in a 4.0 mmφ column, and the solvent flow rate was 0.7
It was adjusted to ml / min. Then, a midget impinger (liquid volume 30 ml, 178 mm × 28 mmφ) was used.

Measurement of phosgene concentration Into the above-mentioned midget impinger, 10 ml of an aqueous aniline solution of 0.3% or more was put, and connected in series in two stages.
A sample gas was collected at a flow rate of 1 liter / min or less. However, in the case of a high-temperature sample gas, the midget impinger was sampled while being cooled with water. After collection, wash the midget impinger with about 5 ml of methanol and combine with
The volume was adjusted to 5 ml. This was injected into the high performance liquid chromatograph, and the peak area of DPU was measured. The DPU concentration in the absorbing solution was determined from the calibration curve while correcting with the corresponding blank value. In addition, the phosgene concentration (C, ppm) in the sample gas was calculated from the following equation, although it may contain carbonyl fluoride.

C = T (0.5 or 0.2 · 15n / 99) (
24.5 / V) ｛(273 + t) / 273｝ (760 / P) where T: DPU concentration in absorption solution (μg / ml),
0.5 or 0.2: A conversion value when converting the molecular weight (212) of DPU into the molecular weight (99) of phosgene and the molecular weight (46) of carbonyl fluoride (0.5 is phosgene, 0.2 is fluorine). Used in carbonyl chloride], n: dilution rate of absorption solution, V: volume of collected air (liter), t: temperature of working place (° C.), P: atmospheric pressure of working place (mmHg).

DPU Separation Experiment Results Separation was performed by reversed-phase chromatography using a styrene-divinylbenzene copolymer having a wide pH range as a stationary phase and a mobile phase of distilled water-methanol. The aniline in the sample had high polarity and showed high solubility in alcohol and distilled water. On the other hand, DPU is soluble in alcohol, but hardly soluble in water. Therefore, 0.02N hydrochloric acid 90% methanol was selected as a mobile phase solvent. FIG. 1 is a chromatogram in a DPU separation experiment.

As shown in FIG. 1, when the present invention was used, various chloroanilines (o- and p-isomers) and aniline could be separated from each other. The calibration curve was prepared based on the peak area using a DPU-methanol standard solution. The linearity was confirmed from 0 to 10 μg / ml. The detection limit is 0.04 μg / ml for DPU with an S / N ratio of 5, and when 10 L of sample gas is sampled, it becomes 7 ppb of phosgene and also corresponds to 4 ppb of carbonyl fluoride.

The collection rate of phosgene and carbonyl fluoride The trapping rate of phosgene with respect to the aniline concentration of the absorbing solution was examined using a tetrabac having a predetermined concentration. As a result, 0.3 at room temperature and pH 5.7-7.3.
%, A good recovery rate of 99 to 100% was obtained. Regarding the influence of pH, a decrease in the recovery rate was observed at pH 4 or lower, and the reaction was incomplete at pH 9 or higher due to the hydroxyl ion concentration. As a result of examining the storage stability of the DPU concentration in the absorbing solution, no interference occurred for 21 days after storage in a cold place. Further, the phosgene collection rate with respect to the collection rate was also measured by the method described above. As a result, under conditions of room temperature and pH 5.7 to 7.3, phosgene could be quantitatively collected up to 1.0 liter / min at a concentration of 0.3%. However, it could not be quantitatively collected at 1.8 liter / min.

Collection rate of phosgene and carbonyl fluoride in combustion gas of chlorine-based organic solvent Next, 1,2,2-trichloro-1,2,2-trifluoroethane (ie, Freon 11
3) Using 1,1,1-trichloroethane, tetrachloroethylene and trichloroethylene, the determination of phosgene and carbonyl fluoride in the ignition combustion gas and the study of the collection rate were performed. Specifically, while monitoring the above-mentioned chlorinated organic solvent in a gas chamber of 1 m ³ by gas chromatography manufactured by Hitachi, the gas chamber was brought into a vaporized equilibrium state, and a predetermined gas concentration was obtained. This equilibrium gas was passed through a constant temperature quartz glass tube in a muffle furnace, and phosgene and carbonyl fluoride generated in the combustion gas at that time were measured by the method described above. Table 1 shows the measured values of the concentrations of phosgene and carbonyl fluoride obtained under these combustion conditions.

[0022]

[Table 1]

However, the effect of the stabilizer concentration in the special grade of trichloroethane and the mixed concentration of phosgene and carbonyl fluoride in Freon 113 are considered. In addition, under the condition of the presence of chlorine gas that causes a chemical reaction with aniline, no interference was exhibited with respect to the absorbing solution, and no reduction in the collection rate was observed. Furthermore, in the absorbing solution, methanol-soluble o, p-
No formation of chloroaniline, 2,4-dichloroaniline or the like was observed.

[0024]

By using the carbonyl chloride determination method of the present invention, it is possible to significantly increase the sensitivity and accuracy of sampling and analysis in the work environment management related to hazardous substance handling work carried out by the business operator, compared with the existing method. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a chromatogram in a separation experiment of DPU.

Claims (1)

(57) [Claims] 1. A sample containing carbonyl chloride at room temperature, p
Reaction with aqueous aniline solution under the conditions of H5.7-7.3
And the product obtained by the above reaction is subjected to high performance liquid chromatography.
The peaks corresponding to the above products were separated by chromatography.
Quantitative determination of carbonyl chloride concentration using calibration curve from area
For quantifying carbonyl chloride
Way .