JP2017031027A - Process for producing nitrosyl chloride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing nitrosyl chloride gas in which nitrosyl chloride can be produced efficiently without by-producing chlorine gas.SOLUTION: Provided is a process for producing nitrosyl chloride characterized to produce by reacting anhydride of 1 or more kind chloride selected from the group consisting of calcium chloride, strontium chloride, cobalt (II) chloride and iron (III) chloride, and nitrogen dioxide at a reaction temperature of -11°C or more and less than 90°C. Preferably, the chloride is characterized to comprise any one or both of calcium chloride and strontium chloride.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for producing nitrosyl chloride.

  Nitrosyl chloride is a component that is a source of the high oxidizing power of aqua regia. Nitrosyl chloride is used for many organic synthesis because it has high reactivity (Patent Documents 1 to 3). In addition, in order to conduct basic test research on the reactivity of nitrosyl chloride, it is necessary to produce a gas cylinder containing nitrosyl chloride at a predetermined concentration.

Currently, industrial methods for producing nitrosyl chloride include a method of reacting nitrosylsulfuric acid and hydrogen chloride (Patent Document 4), a method of reacting sodium chloride and nitric acid (Patent Documents 5 to 7), sodium chloride and nitrogen dioxide. A method of reacting (Non-patent Document 1) and a method of reacting potassium chloride and nitrogen dioxide (Patent Document 8) are known.
Patent Document 8 suggests the possibility of utilizing a reaction between a chloride other than potassium chloride and nitrogen dioxide in the production of nitrosyl chloride. However, Patent Document 8 does not report that the above reaction is actually used for the production of nitrosyl chloride.

JP 2001-2625 A JP 2006-52163 A JP-A-6-306017 Japanese Patent Laid-Open No. 11-278813 Japanese Patent Laid-Open No. 61-0448401 JP 62-065923 A JP 62-065924 A French patent invention No. 1333767

Schroeder, W.M. H. , & Urone, P.M. (1974). Formation of nitrosyl chloride from salt particles in air. Environmental Science & Technology, 8 (8), 756-758.

However, the method of obtaining nitrosyl chloride by reacting nitrosylsulfuric acid with hydrogen chloride or reacting sodium chloride with nitric acid has a problem that chlorine as an impurity gas is by-produced.
Further, in the method of obtaining nitrosyl chloride by reacting sodium chloride or potassium chloride with nitrogen dioxide, the reaction rate is very slow, so that the contact time between nitrogen dioxide and chloride has to be long.

  This invention is made | formed in view of the said situation, and makes it a subject to provide the manufacturing method which can manufacture nitrosyl chloride efficiently, without making chlorine gas by-produce.

In order to develop a method for efficiently producing nitrosyl chloride without producing chlorine gas as a by-product, the present inventor has focused attention on a method for producing nitrosyl chloride by a reaction between sodium chloride and nitrogen dioxide.
The reaction between sodium chloride and nitrogen dioxide can be represented by the following (Reaction Formula 1).
NaCl + 2NO ₂ → NaNO ₃ + NOCl (reaction formula 1)

In the reaction represented by (Reaction Formula 1), impurities are not mixed in the gas phase other than nitrogen dioxide introduced as a raw material gas. However, the reaction represented by (Reaction Formula 1) has a very slow reaction rate.
Therefore, the present inventor changes the almost entire amount of nitrogen dioxide to nitrosyl chloride by increasing the reaction rate while utilizing the advantage that no impurity gas other than the raw material gas is mixed in the reaction represented by (Reaction Formula 1). The manufacturing method was examined.

As a result, it was found that one or more chloride anhydrides selected from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) may be selected as the chloride. .
This invention is made | formed based on said knowledge, The summary is as follows.

(1) One or more chloride anhydrides selected from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) chloride, and nitrogen dioxide are -11 ° C. or more and 90 ° C. A process for producing nitrosyl chloride, which comprises producing by reacting at a reaction temperature of less than
(2) The method for producing nitrosyl chloride according to (1), wherein the chloride necessarily contains one or both of calcium chloride and strontium chloride.
(3) The method for producing nitrosyl chloride according to (1) or (2), wherein the chloride necessarily contains cobalt (II) chloride.
(4) The method for producing nitrosyl chloride according to any one of (1) to (3), wherein the anhydride of chloride and the nitrogen dioxide are brought into contact with each other at a temperature of less than 21 ° C. for reaction.
(5) One or more chloride hydrates selected from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) are anatomized to obtain the chloride anhydride. The method for producing nitrosyl chloride according to any one of (1) to (4), which comprises a step of obtaining.
(6) A reactor having a packed bed formed by filling the anhydride of chloride and a supply device for supplying nitrogen dioxide into the reactor is used, and the nitrogen dioxide is added to the packed bed. The method for producing nitrosyl chloride according to any one of (1) to (5), wherein the method is made to circulate.

  According to the method for producing nitrosyl chloride of the present invention, nitrosyl chloride can be produced efficiently without producing chlorine gas as a by-product.

It is a graph which shows the infrared spectroscopy spectrum of the gas obtained by an example of the manufacturing method of the nitrosyl chloride based on this invention. It is a graph which shows the infrared spectroscopy spectrum of the gas obtained by the other example of the manufacturing method of the nitrosyl chloride based on this invention. It is a graph which shows the infrared spectroscopy spectrum of the gas obtained by the other example of the manufacturing method of the nitrosyl chloride based on this invention.

Hereafter, the manufacturing method of the nitrosyl chloride of this invention is demonstrated in detail.
The inventor first verified the reason why the reaction rate of sodium chloride and potassium chloride with nitrogen dioxide is slow in the reaction represented by the above (Reaction Formula 1). And it was estimated that the main reason for the slow reaction rate is the following first to third reasons.

  The first reason is the influence of moisture adhering to the chloride surface. Nitrosyl chloride is known to react with water to turn into nitrous acid (Magi, L., George, C., & Mirabel, P. (1997). Uptake of nitrosyl chloride (NOCl) by aqueous solutions. The. Journal of Physical Chemistry A, 101 (49), 9359-9366.).

  In addition, it has been reported that the reaction rate between sodium chloride and nitrogen dioxide decreases as the relative humidity increases, and sodium nitrate is less likely to be formed (Karlsson, R., & Ljungstrom, E. (1995). Nitrogen dioxide). and sea salt particles-a laboratory study. Journal of aerosol science, 26 (1), 39-50.).

  There is a possibility that the reaction between chloride, which is a raw material, and nitrogen dioxide is hindered by the influence of moisture. Therefore, it was considered that the reaction rate was increased by removing water from the raw material. Specifically, it was expected that the reaction rate would be increased if a pretreatment was performed to remove water from the raw material before reacting chloride with nitrogen dioxide.

  The second reason is the relative stability of the raw material chloride and the product nitrate. The ease with which the reaction represented by (Reaction Formula 1) proceeds depends on the relative stability of chloride and nitrate. Specifically, the more stable the product nitrate is expected to increase the reaction rate. Therefore, it was inferred that the reaction rate can be increased by performing thermodynamic calculation of the reaction formula and selecting chlorides that make the product (nitrate) more thermodynamically advantageous.

  The third reason is the size of the specific surface area of the chloride material. The reaction between the solid chloride and the gas or liquid nitrogen dioxide proceeds on the surface of the chloride particles. For this reason, when the specific surface area of a chloride particle is small, reaction rate will become slow. Sodium chloride and potassium chloride are industrially produced by precipitation from aqueous solutions. Since sodium chloride and potassium chloride have very high solubility, when precipitated from an aqueous solution, the particles have a large particle size and a small specific surface area. Therefore, in order to increase the reaction rate, it was inferred that it was effective to devise a method for increasing the specific surface area of chloride.

Hereinafter, matters that are important when carrying out the present invention will be described in order.
First, criteria for selecting chloride as a raw material used for reaction with nitrogen dioxide will be described. A procedure for reacting the selected chloride with nitrogen dioxide will be described. Finally, a procedure for determining the concentration of nitrosyl chloride contained in the generated gas will be described.

The chloride used in the present embodiment reacts with nitrogen dioxide according to the general formula shown by the following (Reaction Formula 2) to become nitrosyl chloride.
ACl _n + 2nNO ₂ → A (NO ₃ ) _n + nNOCl (reaction formula 2)
Almost any chloride is applicable to (Scheme 2). When actually selecting the chloride used in the reaction of the present embodiment, it is preferable to select one that has a large negative enthalpy change in the reaction of (Reaction Formula 2) and is more exothermic, and is free of Gibbs during the reaction. The larger the energy change, the more advantageous and preferable the product.

  Numerical values provided in various databases can be used to calculate the enthalpy and entropy of the reaction in (Reaction Formula 2). For example, the numerical values described in the NIST Chemistry WebBook (http://webbook.nist.gov/chemistry/) can be used. For those that are not in such a database, you can use the values described in the paper.

Table 1 shows an example of enthalpy change (ΔH) and Gibbs free energy change (ΔG) per mole of nitrosyl chloride.
As shown in Table 1, the Group 1 element (alkali metal) of the periodic table has a large calorific value (-ΔH and -ΔG are large) when lithium chloride is used, and is chlorinated in the reaction of (Reaction Formula 2). It is expected that the reaction rate of nitrosyl formation will be increased. Similarly, calcium chloride and strontium chloride can be expected to be advantageous for the Group 2 elements of the periodic table. Further, cobalt (II) chloride is considered preferable as the transition metal element.
The conversion rate when nitrosyl chloride is actually produced is generally in the order as predicted above, as shown in the following examples. Therefore, selecting a chloride that is thermodynamically advantageous in the reaction (Scheme 2) is effective in increasing the reaction rate of nitrosyl chloride formation.

  As the chloride that is a raw material used in the present embodiment, a chloride that easily causes a side reaction should be avoided. For example, as shown in the examples described later, when iron (II) chloride was used as the chloride, all of the introduced nitrogen dioxide was absorbed by the chloride, and the formation of nitrosyl chloride could not be confirmed. This is thought to be due to the fact that divalent iron was oxidized to trivalent by the oxidizing power of nitrogen dioxide. Therefore, it is preferable to select a chloride that has the maximum oxidation number of the metal element contained in the chloride, or one that does not cause oxidation of the metal element by nitrogen dioxide.

  Samples that are difficult to handle as chlorides should also be avoided. For example, titanium chloride breaks down into oxides when exposed to the atmosphere. Zinc chloride and nickel chloride are hydrolyzed when the hydrate is dried, and oxides are generated.

  When a particle having a large specific surface area is selected as the chloride, the number of places where the solid chloride and the gas or liquid nitrogen dioxide react with each other increases. However, since chloride has a high solubility in water, it is difficult to obtain particles having a small particle size and a large specific surface area using a general production process via an aqueous solution. Therefore, it is effective to select a chloride that produces a stable hydrate, and denature the chloride hydrate to obtain particles having a large specific surface area.

Specifically, calcium chloride, strontium chloride, cobalt (II) chloride, and iron (III) form a stable hydrate, which is denatured by heating and drying, and has a large specific surface area. Is preferable. On the other hand, lithium chloride, sodium chloride and potassium chloride are not preferable because they do not form a stable hydrate.
In the anhydride obtained by the air dissipation treatment in which the present inventors heated calcium chloride hydrate and lithium chloride hydrate at 200 ° C., the specific surface area of calcium chloride is that of lithium chloride. The value was 10 times or more larger than the specific surface area.

  Chloride has a high solubility in water, and adsorbed water adsorbed on chloride tends to remain in the chloride. When the adsorbed water adsorbed on the chloride reacts with nitrosyl chloride produced by the reaction between the chloride and nitrogen dioxide, the decomposition of nitrosyl chloride proceeds.

As described above, in the present embodiment, as the chloride, one or more chloride anhydrides selected from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) chloride are used. Among these, as the chloride, it is preferable to use calcium chloride or strontium chloride anhydride, which has high production efficiency of nitrosyl chloride.
In this embodiment, it is preferable to have a step of obtaining one or more chloride hydrates selected from the above group to obtain the chloride anhydride.
In particular, since the production rate of nitrosyl chloride is high and nitrosyl chloride can be efficiently produced, it is preferable to use an anhydride obtained by decalcifying calcium chloride hydrate or strontium chloride hydrate.

  In the present embodiment, a mixture of a plurality of chlorides may be used as the chloride. When a mixture of a plurality of chlorides is used as the chloride, it is preferable to always include an anhydride of strontium chloride and / or an anhydride of cobalt (II) chloride. Preferable examples of the mixture of a plurality of chlorides include, for example, a mixture of strontium chloride anhydride and cobalt (II) chloride anhydride, a mixture of calcium chloride anhydride and strontium chloride anhydride, and the like. .

  Strontium chloride can generate nitrosyl chloride most efficiently, and is preferable as a chloride used in a reaction for producing nitrosyl chloride. However, since strontium chloride is a substance that may contaminate the environment, it is preferable to suppress the amount used. By using a mixture of multiple chlorides including strontium chloride anhydride as the chloride, nitrosyl chloride can be efficiently generated using the reaction between strontium chloride and nitrogen dioxide, and the amount of strontium chloride used is suppressed. it can.

Further, when a mixture of a plurality of chlorides is used as the chloride, it is preferable to always contain cobalt (II) chloride. Since most chlorides and nitrates are white, the appearance of the packed bed remains unchanged even when the reaction between nitrogen dioxide and chloride proceeds, and what portion of the packed chloride is used for the reaction. It is difficult to easily determine whether it has happened.
Therefore, the present inventors paid attention to the characteristic color change of the cobalt salt. Anhydrous cobalt chloride (II) and anhydrous cobalt nitrate (III) differ greatly in color. Anhydrous cobalt (II) chloride is blue, and anhydrous cobalt (III) nitrate is light red. Therefore, if a packed layer is formed using cobalt (II) chloride, it can be confirmed by a change in color that cobalt (II) chloride and nitrogen dioxide reacted to change to cobalt (III) nitrate.

Next, the precautions when the chloride actually charged in the reaction tube is reacted with nitrogen dioxide will be described.
In this embodiment, when producing nitrosyl chloride using a reaction apparatus having a reaction tube having a packed bed formed by filling with chloride and a supply device for supplying nitrogen dioxide to the packed bed in the reaction tube. Will be described as an example. In this embodiment, nitrosyl chloride is produced by supplying nitrogen dioxide to the packed bed of the reaction apparatus using a supply device, circulating nitrogen dioxide through the packed bed, and bringing chloride and nitrogen dioxide into contact with each other.

  In this embodiment, one or more chloride anhydrides selected from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) are filled into the reaction tube to form a packed bed. To do.

  When using a plurality of chlorides including strontium chloride anhydride as the chloride, at least one selected from the group consisting of calcium chloride, cobalt (II), and iron (III) chloride on the upstream side of the reaction tube It is preferable to form a packed bed by filling the chloride anhydride with strontium chloride on the downstream side. When nitrogen dioxide is passed from the upstream side of the reaction tube having this packed bed, the chloride filled in the upstream side reacts with a part of the nitrogen dioxide to be converted into nitrosyl chloride. Nitrogen dioxide remaining after passing through the upstream side of the reaction tube passes through the downstream side of the reaction tube, whereby strontium chloride and nitrogen dioxide react with each other and are converted to nitrosyl chloride. As a result, nitrosyl chloride can be generated efficiently even if the amount of strontium chloride used is small compared to the case where the entire packed bed is filled with strontium chloride.

  When a plurality of chlorides containing cobalt (II) chloride are used as the chloride, for example, as the packed layer, one or more chlorides selected from the group consisting of calcium chloride, strontium chloride, and iron (III) chloride are used. It is preferable to form a first region formed by filling an object and a second region made of cobalt (II) chloride partially formed in the first region. Thus, the progress of the reaction between the chloride forming the packed bed and nitrogen dioxide can be easily visually confirmed by the color change in the second region. Therefore, it becomes very easy to determine the replacement time of the chloride forming the packed bed.

  In this embodiment, before reacting the chloride anhydride with nitrogen dioxide, it is preferable to perform a step of defrosting the chloride hydrate to obtain the chloride anhydride. Specifically, for example, after filling a hydrate of chloride into the reaction tube, the reaction tube is heated and heated while flowing dry nitrogen or air into the reaction tube, and the reaction tube is heated until generation of water vapor is eliminated. It is preferable to perform a wind-dissipating treatment that heats at a temperature of 100 to 350 ° C., and more preferably to perform a wind-dissipating treatment that heats at 200 to 300 ° C. When the heating temperature of the reaction tube is 100 ° C. or higher, more preferably 200 ° C. or higher, moisture as hydrated water of chloride and adsorbed water adsorbed on the chloride do not remain, which is preferable. In addition, when the heating temperature of the reaction tube is 350 ° C. or lower, more preferably 300 ° C. or lower, the heating cost can be suppressed and the specific surface area of the chloride having a low melting point can be prevented by heating the reaction tube. .

  In the present embodiment, before reacting the chloride anhydride produced by wind dissociation and the like with nitrogen dioxide, a drying treatment is performed to remove the adsorbed water adsorbed on the chloride anhydride. Also good. As the drying treatment, for example, after filling the reaction tube with chloride anhydride, the reaction tube is heated and heated while flowing dried nitrogen or air, and the reaction tube is kept until no steam is generated. A method of heating, a method of removing the adsorbed water by reducing the pressure inside the reaction tube after filling, and the like are mentioned.

In the production method of the present embodiment, it is needless to say that it is not always necessary to carry out a wind-breaking treatment of chloride hydrate in a reaction tube, and a chloride anhydride that has been previously wind-treated in another place is reacted. The tube may be filled.
In addition, when a chloride anhydride is available as a commercial product, by utilizing it, it is possible to omit the defrosting treatment of the chloride hydrate and simplify the manufacturing process.

In the present embodiment, the reaction rate between chloride and nitrogen dioxide can be increased by increasing the contact efficiency between the surface of the chloride that is solid and the nitrogen dioxide that is gas or liquid (Non-patent Document 1). Specifically, it is preferable to reduce the particle diameter of the chloride to be used as much as possible and increase the specific surface area of the chloride within a range where the pressure loss does not become too large.
In addition, the packing density of the chloride filled in the reaction tube of the reaction apparatus is uneven, and the reaction efficiency is lowered when a part of the chloride in the packed bed is difficult to contribute to the reaction. For this reason, it is preferable to use what adjusted the particle | grains as needed as a chloride. When the sized chloride particles are used, the packing density of the chloride packed in the reaction tube becomes uniform, so that the entire packed chloride contributes to the reaction and good reaction efficiency is obtained.

  The nitrogen dioxide supplied to the packed bed formed by filling with chloride may be diluted with a diluent gas such as nitrogen. The concentration of diluted nitrogen dioxide is preferably 10 ppm or more, more preferably 30 ppm or more, and even more preferably 200 ppm or more. There is no upper limit to the concentration of nitrogen dioxide introduced into the packed bed, and only nitrogen dioxide may be used. When the concentration of nitrogen dioxide introduced into the packed bed is 10 ppm or more, nitrogen dioxide sufficiently adheres on the chloride, so that the production efficiency of nitrosyl chloride is improved.

In the case of introducing diluted nitrogen dioxide into the packed bed, examples of the method for controlling the concentration of nitrogen dioxide include the following methods.
For example, when a gas cylinder containing diluted nitrogen dioxide is connected to the reaction tube, a method of preparing a plurality of gas cylinders having different nitrogen dioxide concentrations and selecting the gas cylinder at an appropriate time can be used. In addition, by supplying a dilution gas such as nitrogen and nitrogen dioxide (or nitrogen dioxide diluted with a dilution gas) to the reaction tube at a predetermined flow rate at a predetermined ratio, the mixed gas of the dilution gas and nitrogen dioxide is reacted. You may use the method of supplying to a pipe | tube.

  Nitrogen dioxide (or diluted nitrogen dioxide) supplied to the packed bed of the reaction tube may be a gas, or a part or all of it may be a liquid. When some or all of the nitrogen dioxide supplied to the packed bed is liquid, contact between chloride and nitrogen dioxide is further promoted, and the reaction rate is further improved. Therefore, the production efficiency of nitrosyl chloride is further improved.

In the production method of the present embodiment, chloride and nitrogen dioxide are reacted at a reaction temperature of −11 ° C. or higher and lower than 90 ° C. to generate nitrosyl chloride. By setting it as said reaction temperature, reaction rate becomes quick and the production | generation efficiency of nitrosyl chloride can be raised.
In the production method of the present embodiment, it is preferable that the anhydride of chloride and nitrogen dioxide are brought into contact with each other at a temperature of less than 90 ° C., preferably 23 ° C. (room temperature) or less. By setting the reaction temperature to 23 ° C. or less, the production efficiency of nitrosyl chloride is remarkably improved.

Moreover, in the manufacturing method of this embodiment, it is more preferable to make a chloride anhydride and nitrogen dioxide contact and react at the temperature below 21 degreeC. In general, the higher the relative pressure with respect to the saturated vapor pressure at each temperature, the easier the gas is adsorbed on the surface of the solid. Nitrogen dioxide has a boiling point of 21 ° C., and by making the reaction temperature lower than the boiling point (21 ° C.), the adsorption of nitrogen dioxide on the chloride surface is promoted, the reaction rate is increased, and the production efficiency of nitrosyl chloride is further increased. Further improvement.
More preferably, the chloride anhydride and nitrogen dioxide are brought into contact with each other at a temperature of 5 ° C. or less for reaction. In this case, adsorption of nitrogen dioxide on the chloride surface is further promoted, and the production efficiency of nitrosyl chloride is further improved.

Moreover, in the manufacturing method of this embodiment, the anhydride of chloride and nitrogen dioxide are contacted at a temperature of -11 ° C. or more and reacted. Since the melting point of nitrogen dioxide is −11 ° C., the temperature (reaction temperature) at which the chloride anhydride and nitrogen dioxide are brought into contact with each other is set to −11 ° C. or higher, so that a solid of nitrogen dioxide is precipitated and It can be prevented that the production efficiency of nitrosyl is reduced. Even when the temperature is set to -11 ° C or higher, depending on the concentration of nitrogen dioxide to be introduced, it is expected that nitrogen dioxide partially condenses on the chloride surface. Since the contact with nitrogen is further promoted, the reaction rate is considered to increase.
Further, the temperature at which the chloride anhydride and nitrogen dioxide are brought into contact with each other is preferably 0 ° C. or higher, so that the cost required for cooling can be suppressed, which is preferable.

  When unreacted residual nitrogen dioxide exists, the nitrosyl chloride gas generated by the production method of the present embodiment is discharged from the reaction tube together with the residual nitrogen dioxide as a nitrosyl chloride-containing gas. When nitrogen dioxide diluted with a diluent gas is used as nitrogen dioxide, a nitrosyl chloride-containing gas containing the diluent gas is discharged from the reaction tube. The nitrosyl chloride-containing gas discharged from the discharge pipe may be diluted with a diluent gas such as nitrogen as necessary.

  Subsequently, a procedure for estimating the concentration of nitrosyl chloride in the nitrosyl chloride-containing gas generated according to the above procedure will be described. There are few means for examining the concentration of nitrosyl chloride, and a literature survey conducted by the present inventor concluded that measurement by infrared absorption spectroscopy is the simplest and most reliable.

  The infrared spectroscopic spectrum and detailed absorption wave number of nitrosyl chloride are described in the following literature (Non-patent Document 1 and absorption spectrum assignment: Landau, L., & Fletcher, WH (1960). The infraspected spectrum and potential function of nitrosyl chloride.Journal of Molecular Spectroscopy, 4 (1), 276-283.).

Each peak is in a position that overlaps with the absorption spectrum of water vapor, but by calculating the difference spectrum between the spectrum obtained by measurement and the absorption spectrum of water vapor, it is possible to obtain the spectra of nitrogen dioxide and nitrosyl chloride, respectively. Is possible.
However, there are several problems in determining the concentration of nitrosyl chloride generated by infrared spectroscopy. That is, even when measuring a nitrosyl chloride-containing gas having the same concentration, the detected value varies greatly depending on the type of infrared spectrometer used and the gas analysis cell. Furthermore, even when the same apparatus is used, the detected value varies every day when the measurement is performed. For this reason, there is a problem that a calibration curve once created is not always reliable.

Therefore, the present inventor estimated the concentration of the generated nitrosyl chloride using two methods.
The first method is to make a calibration curve of the peak intensity of the infrared spectrum against the nitrogen dioxide concentration just before reacting with chloride, and estimate that the reduced nitrogen dioxide concentration before and after the reaction changed to nitrosyl chloride. .
The second method calculates the concentration of generated nitrosyl chloride using the concentration of the introduced nitrogen dioxide gas and the relative values of the detected peak intensities of nitrogen dioxide and nitrosyl chloride in the infrared spectroscopic measurement results. It is. Details of each are described below.

  The first method estimates the amount of nitrosyl chloride generated using the change in the detected amount of nitrogen dioxide. There are many means for measuring the concentration of nitrogen dioxide, and the concentration of the introduced nitrogen dioxide gas can be accurately determined. Assuming that the reaction proceeds according to the above reaction formula 2, all the consumed nitrogen dioxide is nitrosyl chloride. Therefore, it is possible to calculate the concentration of the generated nitrosyl chloride by measuring the concentration of nitrogen dioxide remaining in the nitrosyl chloride-containing gas after passing through the reaction tube.

  However, as described above, the concentration of nitrogen dioxide does not necessarily correspond one-to-one with the peak intensity of the infrared spectrum, so it is important to create a calibration curve immediately before measurement and calculate the concentration accordingly. . Also, for some time after the start of the reaction, nitrogen dioxide does not reach the position of the infrared spectrometer, and there is a risk of underestimating the residual concentration of nitrogen dioxide, so the peak intensities of both nitrogen dioxide and nitrosyl chloride are stable. You should postpone the evaluation until you do.

  The second method uses a known concentration of nitrogen dioxide gas as the raw material, and calculates the ratio between the detected intensity of nitrogen dioxide and the detected intensity of nitrosyl chloride in the infrared spectrum of the nitrosyl chloride-containing gas after passing through the reaction tube. It is what you use. In the first method described above, it is necessary to create a calibration curve for each measurement, which is very laborious. The difference in the detection intensity depending on the measurement schedule is expected to be derived from the difference in the atmospheric conditions between days and the instability of the detection sensitivity of the semiconductor detector. Therefore, it is considered that the relative intensity within the same spectrum is a reliable value. Assuming that the consumption of nitrogen dioxide and the generation of nitrosyl chloride proceed according to the above (Reaction Formula 2), the molar concentration of nitrosyl chloride and nitrogen dioxide follows the following formula.

Introduced NO ₂ concentration (mol) = 2 × NOCl concentration after passing through the reactor (mol) + NO ₂ concentration after passing through the reactor (mol)
Therefore, if the relative ratio of the concentration of nitrosyl chloride and nitrogen dioxide contained in the nitrosyl chloride-containing gas after passing through the reaction tube is known, the concentration of each gas can be determined.

  Since nitrogen dioxide and nitrosyl chloride are different types of molecules, the infrared absorption cross sections at the respective peak positions are different. Therefore, it is first necessary to create a calibration line for each molecular species. The calibration line for nitrogen dioxide is created using a standard gas. The calibration line for nitrosyl chloride is prepared using the nitrosyl chloride concentration estimated by the first method described above. Using the obtained calibration line, the concentrations of nitrogen dioxide and nitrosyl chloride contained in the nitrosyl chloride-containing gas after passing through the reaction tube are estimated. Since the actual concentration of introduced nitrogen dioxide is known, the concentration of each component is increased proportionally so that the calculation result and the concentration of introduced nitrogen dioxide do not contradict each other. Thus, once an accurate calibration curve is created, the amount of nitrosyl chloride can be easily estimated.

  In the method for producing nitrosyl chloride of the present embodiment, nitrosyl chloride can be produced by reacting solid chloride anhydride with gaseous or liquid nitrogen dioxide. For this reason, unlike the nitrosyl chloride production method using a liquid raw material that inevitably contains water as an impurity, water is not mixed as an impurity, and further, the produced nitrosyl chloride is not hydrolyzed, preferable. In addition, chlorine is not generated as a by-product in a reaction using a more reactive reagent such as nitrosylsulfuric acid, which is preferable.

Furthermore, in the method for producing nitrosyl chloride of the present embodiment, high-purity nitrosyl chloride can be produced as compared with the prior art using sodium chloride or potassium chloride as the chloride. Therefore, the nitrosyl chloride-containing gas produced by the method for producing nitrosyl chloride of the present embodiment can be used for test studies or organic reactions without being purified.
Moreover, in the manufacturing method of the nitrosyl chloride of this embodiment, nitrosyl chloride can be easily generated by arbitrary generation amounts (molar number) by controlling the usage-amount (molar number) of nitrogen dioxide. Further, by controlling the concentration of nitrogen dioxide to be reacted with the chloride anhydride with a dilution gas, a nitrosyl chloride-containing gas containing nitrosyl chloride at an arbitrary concentration can be obtained.

  Therefore, a method is used in which a reactor having a packed bed formed by filling chloride anhydride and a reactor having a supply device for supplying nitrogen dioxide into the reactor is used, and nitrogen dioxide is circulated through the packed bed. In such a case, the amount of nitrosyl chloride generated easily can be adjusted even in the production stage by controlling the amount of nitrogen dioxide supplied to the packed bed. In addition, nitrogen dioxide diluted with diluent gas is used as nitrogen dioxide to be circulated in the packed bed, and by controlling the mixing ratio of dilution gas and nitrogen dioxide, it contains nitrosyl chloride that is easily generated even in the production stage The concentration of nitrosyl chloride in the gas can be adjusted.

  In the method for producing nitrosyl chloride of this embodiment, nitrogen dioxide and chloride are reacted stoichiometrically, regardless of the concentration of nitrogen dioxide to be introduced, so that half the amount of nitrosyl chloride in terms of molar amount is converted. Can be generated. Therefore, by appropriately selecting the molar amount (molar concentration) of nitrogen dioxide to be introduced, an arbitrary molar amount (molar concentration) of nitrosyl chloride gas can be produced.

According to the present embodiment, it is possible to solve the following problems that may occur in the prior art.
(I) In the conventional method of obtaining nitrosyl chloride by reacting nitrosylsulfuric acid with hydrogen chloride, concentrated sulfuric acid containing a large amount of chlorine and nitrogen oxides is generated as a by-product, and the raw material nitrosylsulfuric acid is not sensitive to humidity. The problem of being unstable and difficult to preserve due to its high corrosivity.
(Ii) In the conventional method in which sodium chloride and nitric acid are reacted, nitrosyl chloride and an equimolar amount of chlorine are generated, and water is mixed as an impurity to cause the reaction to proceed as an aqueous solution, and nitrosyl chloride is partially The problem of hydrolysis.
(Iii) The conventional method of reacting sodium chloride or potassium chloride with nitrogen dioxide requires a very slow reaction rate, requires a longer contact time between nitrogen dioxide and chloride, and a large amount of unreacted nitrogen dioxide. The problem is that it needs to be refined because it remains.
(Iv) The problem is that it is difficult to control the concentration of nitrosyl chloride produced by a conventional method at the production stage.
(V) Because of (iv), it becomes necessary to cool nitrosyl chloride gas, which has high toxicity and high corrosiveness, to cool to dry ice temperature etc. and store it in a liquid state. The problem of cost.
Further, according to the present embodiment, a high-purity nitrosyl chloride gas having a low content of reactive impurities such as nitrogen oxides, hydrogen chloride, and chlorine can be easily produced at an arbitrary concentration in a necessary amount. It is also possible.

  Next, the present invention will be specifically described based on examples, but the present invention is not limited to the examples.

[Types of chlorides and generation of nitrosyl chloride in reactions at room temperature]
(Examples 1-4, Comparative Examples 1-4)
Table 2 and the chlorides of Examples 1 to 4 and Comparative Examples 1 to 4 shown below were weighed in the masses shown below, filled in quartz glass tubes (reaction tubes) for reaction, and the top and bottom of the chlorides were Fixed with silica wool.

Example 1 Calcium chloride dihydrate (Kanto Chemical, special grade, purity 99.0-103.0%) 0.30 g
(Example 2) Strontium chloride hexahydrate (Kanto Chemical, special grade, purity 99.0%) 0.40 g
(Example 3) Cobalt (II) chloride hexahydrate (Kanto Chemical Co., Ltd., high purity reagent, purity 99.95% or more) 0.40 g
(Example 4) Iron (III) chloride anhydride (Wako Pure Chemical Industries) 0.40 g

(Comparative Example 1) Lithium chloride (Wako Pure Chemicals, special grade, purity 99.0% or more) 0.30 g
(Comparative example 2) Sodium chloride (Kanto Chemical, volumetric analysis, purity 99.95% or more) 0.30 g
(Comparative Example 3) Potassium chloride (Kanto Chemical, special grade, purity 99.5% or more) 0.30 g
(Comparative Example 4) Iron (II) chloride tetrahydrate (Kanto Chemical, special grade, purity 99.0-102.0%) 0.40 g

A mantle heater was used while flowing nitrogen gas (purity 99.9999% or more) at 70 cm ³ / min into the quartz glass tubes filled with chlorides of Examples 1 to 4 and Comparative Examples 1 to 4 using a supply device. The quartz glass tube was heated up to 200 ° C. using and was subjected to drying treatment (winding treatment in Examples 1 to 3) until generation of water vapor from the quartz glass tube was not confirmed. After the drying treatment, the reaction mixture was cooled to room temperature (23 ° C.), which is the reaction temperature while continuing the nitrogen flow, and nitrogen gas (reaction gas) containing 31 ppm of nitrogen dioxide was passed through the quartz glass tube at 50 cm ³ / min to react. A test was conducted.

  A gas analysis cell was installed in an infrared spectrometer (Thermo Scientific, Nicolet iS50FT-IR), and the gas obtained by the reaction test was analyzed to calculate the conversion rate and purity of nitrogen dioxide. As for the conversion rate and purity of nitrogen dioxide, the reaction gas was passed through the quartz glass tube for 30 minutes or more, and the concentration of nitrosyl chloride in the gas generated from the quartz glass tube and the concentration of unreacted nitrogen dioxide remained stable. After confirming this, calculation was performed using the following formula. The test results of Examples 1 to 4 and Comparative Examples 1 to 4 are shown in Table 2.

Conversion rate (%) = [A × 2 / (B + A × 2)] × 100
Purity (%) = A / (B + A) × 100
In the above formulas showing the conversion rate and purity, A indicates the concentration (mol%) of nitrosyl chloride in the gas after passing through the quartz glass tube (reaction tube) by the reaction test, and B indicates the quartz glass tube (reaction tube) by the reaction test. ) Shows the concentration (mol%) of nitrogen dioxide in the gas after passing through.

  Moreover, the chlorine concentration analysis using the orthotolidine method was also implemented about the gas obtained by each reaction test.

As shown in Table 2, in Examples 1 to 4, it was confirmed that the conversion rate and purity were higher than those of Comparative Examples 1 to 3, and nitrosyl chloride was efficiently generated.
Moreover, it was confirmed that Example 2 using strontium chloride had higher conversion and purity and higher production efficiency of nitrosyl chloride than Example 1 using calcium chloride.
Although the enthalpy of reaction between calcium chloride and strontium chloride is almost the same as shown in Table 1, there is a very large difference in the production efficiency of nitrosyl chloride as shown in Table 2. Appears. From this, it was confirmed that strontium chloride shows a specifically high nitrosyl chloride generation efficiency.
In any reaction test, chlorine gas was not detected from the gas obtained after the reaction.

  Further, in Comparative Examples 1 to 3 using alkali metal chloride as the chloride, the conversion rate of Comparative Example 1 using lithium chloride as the chloride is the highest, and there is a tendency to coincide with the order of formation enthalpy shown in Table 1. It was seen.

In Comparative Example 4 using iron (II) chloride as the chloride, neither nitrogen dioxide nor nitrosyl chloride was detected. In Comparative Example 4, it was confirmed that the chloride in the quartz glass tube was discolored and colored light purple by performing a reaction test. This is because Fe ²⁺ in iron (II) chloride is oxidized to Fe ³⁺ by contacting with nitrogen dioxide having oxidizing power, and iron nitrate (III) is produced. As a result, nitrogen dioxide introduced into the quartz glass tube is reduced. This is presumed to be due to adhesion to the chloride surface.

[Effect of chloride content on nitrosyl chloride generation reaction]
(Example 5)
A reaction test was carried out in the same manner as in Example 1 except that 3.0 g of calcium chloride dihydrate (Kanto Chemical Co., Ltd., special grade, purity 99.0-103.0%) was weighed and used as the chloride. The conversion and purity were determined. The test results of Example 5 are shown in Table 3.
For comparison, Table 3 also shows the results of Example 1 which was carried out with the amount of calcium chloride dihydrate set to 0.3 g.

  As shown in Table 3, in Example 5 using 3.0 g of chloride, the amount of chloride was larger than in Example 2 using 0.3 g of chloride. It was confirmed that nitrosyl chloride was efficiently produced by sufficient contact, high conversion and purity.

[Effect of reaction temperature on nitrosyl chloride evolution reaction]
(Example 6)
A reaction test was conducted in the same manner as in Example 5 except that the quartz glass tube was placed in a constant temperature water bath and the reaction temperature was 10 ° C., and the conversion and purity were determined.
(Example 7)
A reaction test was conducted in the same manner as in Example 5 except that the quartz glass tube was ice-cooled to set the reaction temperature to 0 ° C., and the conversion and purity were determined.

(Example 8)
A reaction test was performed in the same manner as in Example 5 except that the quartz glass tube was cooled with a chiller and the reaction temperature was set to -11 ° C, and the conversion and purity were determined.
Example 9
A reaction test was conducted in the same manner as in Example 5 except that the reaction temperature was 80 ° C. by heating the quartz glass tube with a heater, and the conversion and purity were determined.

(Comparative Example 5)
A reaction test was conducted in the same manner as in Example 5 except that the reaction temperature was 90 ° C. by heating the quartz glass tube with a heater, and the conversion and purity were determined.

Table 4 shows the test results of Examples 6 to 9 and Comparative Example 5.
Table 4 also shows the results of Example 5 in which the reaction temperature is room temperature (23 ° C.) for comparison.

  As shown in Table 4, when calcium chloride was used as the chloride, it was confirmed that the production rate of nitrosyl chloride greatly changed depending on the reaction temperature. Specifically, Example 5 in which the reaction temperature is room temperature (23 ° C.), Example 6 in which the reaction temperature is 10 ° C., Example 7 in which the reaction temperature is 0 ° C., and Implementation in which the reaction temperature is −11 ° C. In Example 8 and Example 9 where the reaction temperature was 80 ° C., it was confirmed that nitrosyl chloride was efficiently produced with higher conversion and purity than Comparative Example 5 where the reaction temperature was 90 ° C. In particular, in Example 8 where the reaction temperature was -11 ° C, Example 7 where the reaction temperature was 0 ° C, and Example 6 where the reaction temperature was 10 ° C, the amount of nitrosyl chloride produced was large.

(Example 10)
A reaction test was performed in the same manner as in Example 2 except that the quartz glass tube was placed in a constant temperature water bath and the reaction temperature was 10 ° C., and the conversion and purity were determined.
(Example 11)
A reaction test was conducted in the same manner as in Example 2 except that the quartz glass tube was ice-cooled to set the reaction temperature to 0 ° C., and the conversion and purity were determined.

Table 4 shows the results of the reaction tests of Example 10 and Example 11.
Table 4 also shows the results of Example 2 in which the reaction temperature is room temperature (23 ° C.) for comparison.

  As shown in Table 4, it was confirmed that when strontium chloride was used as the chloride, the production rate of nitrosyl chloride greatly changed depending on the reaction temperature. In addition, compared with Example 2 in which the reaction temperature is room temperature (23 ° C.), Example 10 in which the reaction temperature is 10 ° C. and Example 11 in which the reaction temperature is 0 ° C. have high conversion and purity. It was confirmed that nitrosyl chloride was efficiently produced.

  In Example 11 where the reaction temperature was 0 ° C. and strontium chloride was used as the chloride, the infrared spectrum of the gas obtained by the reaction test was measured. The result is shown in FIG. As shown in FIG. 1, in Example 11, the peak derived from unreacted nitrogen dioxide was weak, the intensity of the peak derived from nitrosyl chloride was strong, and it was confirmed that the generation efficiency of nitrosyl chloride was high.

[Production of high purity nitrosyl chloride using strontium chloride]
(Example 12)
1.0 g of strontium chloride hexahydrate (Kanto Chemical, special grade, purity 99.0%) was weighed and used as chloride, and the reaction temperature was 0 ° C by cooling the quartz glass tube with ice. Except for the above, a reaction test was conducted in the same manner as in Example 1 to obtain the conversion and purity.
(Example 13)
A reaction test was conducted in the same manner as in Example 12 except that nitrogen gas (reaction gas) containing 200 ppm of nitrogen dioxide was passed through the quartz glass tube at 10 cm ³ / min, and the conversion and purity were determined.

The results of the reaction test of Example 12 and Example 13 are shown in Table 5.
Table 5 also shows the results of Example 11 in which 0.40 g of strontium chloride hexahydrate was used for comparison.

From the results of Example 11 and Example 12 shown in Table 5, it was confirmed that by increasing the amount of strontium chloride, the conversion rate and purity were increased, and the residual amount of nitrogen dioxide was greatly reduced.
Further, from the results of Example 12 and Example 13, it was confirmed that increasing the concentration of nitrogen dioxide increased the conversion rate and purity and produced nitrosyl chloride efficiently. This is because the concentration of nitrogen dioxide increases, the relative pressure of nitrogen dioxide to the saturated vapor pressure increases, the amount of nitrogen dioxide adhering to the surface of strontium chloride increases, and the more reactive dinitrogen tetroxide. It is expected that the reaction rate was improved by promoting the production of.

In Example 12 and Example 13, the infrared spectrum of the gas obtained by the reaction test was measured. FIG. 2 is a graph showing the infrared spectrum of the gas obtained by the production method of Example 12. FIG. 3 is a graph showing the infrared spectrum of the gas obtained by the production method of Example 13.
From Table 5, FIG. 2, and FIG. 3, in Example 12 and Example 13, it was confirmed that the residual amount of nitrogen dioxide is low and it is high purity.

[Test of mixing cobalt chloride and strontium chloride]
(Example 14)
As chloride, 1.0 g of strontium chloride hexahydrate (Kanto Chemical, special grade, purity 99.0%) and cobalt chloride hexahydrate (Kanto Chemical, high purity reagent, purity 99.95% or more) 0.1 g was mixed and used, and the reaction temperature was 0 ° C. by cooling the quartz glass tube with ice, and nitrogen gas (reaction gas) containing 200 ppm of nitrogen dioxide was applied to the quartz glass tube at 10 cm ³ / min. A reaction test was conducted in the same manner as in Example 1 except that the solution was distributed, and the conversion and purity were determined. The test results are shown in Table 5.

  As shown in Table 5, in Example 14 using strontium chloride and cobalt chloride as chlorides, the results were the same as in Example 13 using only strontium chloride. From this, it was confirmed that by using a mixture of strontium chloride and cobalt chloride, nitrosyl chloride can be efficiently generated using the reaction of strontium chloride and nitrogen dioxide, and the amount of strontium chloride used can be suppressed. .

Moreover, it is known that cobalt differs greatly in color for every compound. Cobalt chloride hydrate is red, cobalt chloride anhydride is blue, and cobalt nitrate anhydride is light red. In the reaction test of Example 14, the state of the filled chloride could be confirmed by observing the color change in the quartz glass tube.
That is, the completion of the drying process was confirmed by the fact that the color of cobalt chloride changed from red to blue. Furthermore, after the reaction test of nitrosyl chloride, a part of the packed cobalt chloride on the upstream side of the reaction gas was changed to light red. By observing this color change, it was possible to estimate the proportion of chloride consumed to generate nitrosyl chloride in the filled chloride.
There are few chlorides except cobalt chloride that show such a clear color change, and it is considered that the progress of the reaction can be easily estimated by mixing cobalt chloride.

Claims (6)

  Reaction of at least -11 ° C and less than 90 ° C with one or more chloride anhydrides selected from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) chloride and nitrogen dioxide A process for producing nitrosyl chloride, characterized by reacting at a temperature.   The method for producing nitrosyl chloride according to claim 1, wherein the chloride contains one or both of calcium chloride and strontium chloride.   The method for producing nitrosyl chloride according to claim 1 or 2, wherein the chloride contains cobalt (II) chloride.   The method for producing nitrosyl chloride according to any one of claims 1 to 3, wherein the anhydride of the chloride and the nitrogen dioxide are brought into contact with each other at a temperature of less than 21 ° C to be reacted.   A process of obtaining one or more chloride hydrates from the group consisting of calcium chloride, strontium chloride, cobalt (II), and iron (III) to obtain an anhydride of the chloride. It has it, The manufacturing method of the nitrosyl chloride as described in any one of Claims 1-4 characterized by the above-mentioned.   Using a reactor having a packed bed formed by filling the chloride anhydride and a supply device for supplying nitrogen dioxide into the reactor, the nitrogen dioxide is circulated through the packed bed. The method for producing nitrosyl chloride according to any one of claims 1 to 5.

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