JPH07228563A - Production of high-purity acetonitrile - Google Patents

Abstract

PURPOSE:To industrially and advantageously obtain acetonitrile for chromatography containing no hydrogen cyanide by substantially completely removing hydrogen cyanide contained as an impurity causing hindrance in accurate analysis when using acetonitrile as a reagent for liquid chromatography. CONSTITUTION:Hydrogen cyanide-containing acetonitrile is treated with a compound of a metal element selected from a group consisting of vanadium, chromium, manganese, thallium, lead, elements of the group Ib, the group IIb and the group VIII of the Periodic Table or both the metal element and a porous adsorbent, and then distilled to provide the objective method for producing high-purity acetonitrile for liquid chromatography substantially not containing hydrogen cyanide.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention substantially completely removes hydrogen cyanide mixed in acetonitrile used as a reagent for liquid chromatography when separating and purifying a trace amount of a target component or separating and analyzing with high sensitivity. The present invention relates to a method for producing high-purity acetonitrile for hydrogen chromate-free liquid chromatograph.

[0002]

BACKGROUND ART Acetonitrile is widely used as a solvent for preparing an eluent in liquid chromatographic analysis.
Acetonitrile for liquid chromatographs has conventionally been the most important quality item because of its low absorbance. However, with the recent remarkable progress of technology in various fields, acetonitrile for liquid chromatography is not only low in absorbance but also a high-purity product in which a trace amount of impurities that may react with an analytical sample is removed. It has become necessary. That is, if a trace amount of reactive impurities are contained, the impurities react with the trace components of the analysis target to reduce the concentration of the components or cause different peaks to appear, which causes a great obstacle to accurate analysis. I will end up. Usually, acetonitrile for liquid chromatography is produced by various purification methods from industrially produced acetonitrile (hereinafter referred to as industrial acetonitrile). However, since industrial acetonitrile is a by-product in producing acrylonitrile by an ammoxidation reaction of propylene, etc., acrylonitrile, allyl alcohol, acetone,
It contains many types of impurities such as hydrogen cyanide. Various techniques have been proposed so far as a method for purifying this industrial acetonitrile to obtain acetonitrile for liquid chromatography. However, acetonitrile obtained by these methods has almost completely removed impurities such as acrylonitrile, allyl alcohol, and acetone,
Although it can be used for liquid chromatography,
Since hydrogen cyanide is not completely removed and remains in a trace amount, there has been a problem that the residual hydrogen cyanide interferes when used for special analysis, high sensitivity and high precision analysis.

That is, since hydrogen cyanide is highly active and has a property of reacting with various compounds, when a component to be analyzed reacts with hydrogen cyanide, a different peak generated by the reaction other than the target peak in the liquid chromatographic analysis is chromatographed. This is because it appears on the gram. Under such circumstances, a high-purity product containing not only a substance that affects the absorbance but also hydrogen cyanide has been strongly demanded as acetonitrile for liquid chromatography. Hitherto, as a method for removing hydrogen cyanide in acetonitrile, a treatment method with an alkaline aqueous solution and a distillation method have been proposed. However, although the treatment method with an alkaline aqueous solution is effective in reducing a high concentration of hydrogen cyanide to a very small amount, it is not effective in removing a very small amount of hydrogen cyanide, and also causes hydrolysis of acetonitrile, thereby generating it. There is a drawback that ammonia and ammonium acetate have a bad influence on liquid chromatographic analysis. Further, although the distillation method is a method that can remove hydrogen cyanide relatively easily, it does not separate well from acetonitrile under normal distillation conditions. In order to completely separate hydrogen cyanide and acetonitrile, it is necessary to repeat distillation, but this causes a problem that work efficiency and production efficiency become low. Further, the multistage rectification has a drawback that enormous equipment cost is required.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in order to prevent the accurate analysis from being hindered by hydrogen cyanide contained impurities when acetonitrile is used as a reagent for liquid chromatography. It is an object of the present invention to provide a novel method for producing acetonitrile for hydrogen cyanide-free liquid chromatography, which is capable of substantially completely removing hydrogen cyanide by an extremely easy method.

[0005]

To achieve the above object, the present invention has the following constitution. "(1) Acetonitrile containing hydrogen cyanide is vanadium, chromium, manganese, thallium, lead, Ib
Substantially hydrogen cyanide characterized by being treated with a compound of a metal element selected from the group consisting of Group IIIb, Group IIb and Group VIII (hereinafter abbreviated as "metal compound according to the present invention") and then distilled. A method for producing high-purity acetonitrile for liquid chromatography, which is not contained in. (2) A method for producing high-purity acetonitrile for liquid chromatograph substantially free of hydrogen cyanide, which comprises treating hydrogen cyanide-containing acetonitrile with the metal compound according to the present invention and a porous adsorbent, and then distilling. "

That is, the present inventors have conducted extensive studies to achieve the above object, and as a result, vanadium, chromium, manganese, thallium, and lead, and Ib group and IIb group of the periodic table.
Group A and Group VIII metal elements rapidly react with hydrogen cyanide in acetonitrile to form a stable anionic metal cyanide complex also in acetonitrile, and this anionic complex is porous. To be easily adsorbed on a water-soluble adsorbent, and to complete the production method of the present invention capable of separating and removing hydrogen cyanide from acetonitrile containing hydrogen cyanide extremely efficiently in a short time and without requiring special equipment or condition setting Arrived

Examples of the metal compound according to the present invention used in the present invention include vanadium, chromium, manganese, thallium, lead, metal elements of Group Ib of the periodic table, that is, copper, silver,
Gold, metal elements of Group IIb of the Periodic Table, ie, zinc, cadmium, mercury, and metal elements of Group VIII of the Periodic Table, ie, metal elements such as iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum. Compounds of Examples of the form of the compound of these metal elements as a metal compound include halides (eg, chloride, bromide, etc.), nitrates, sulfates, perchlorates, carboxylates (eg formate, acetate, higher fatty acid). Salt etc.)
The salt form and the like are preferable, but the salt form is not limited thereto, and the salt form that is not in the salt form can be sufficiently used.

Specific examples of the metal compound according to the present invention include vanadium chloride, manganese chloride, cupric chloride, zinc chloride, ruthenium chloride, rhodium chloride, palladium chloride, osmium chloride, iridium chloride, thallium nitrate and nitric acid. Lead, chromium nitrate, silver nitrate, cadmium nitrate,
Mercury nitrate, ferric nitrate, cobalt nitrate, palladium nitrate, manganese sulfate, copper sulfate, zinc sulfate, ferrous ammonium sulfate, cobalt sulfate, nickel sulfate, silver perchlorate, thallium formate, manganese acetate, lead acetate , Copper acetate, silver acetate, cobalt acetate, palladium acetate, manganese stearate, vanadium oxide sulfate, chloroauric acid, chloroplatinic acid and the like, but it goes without saying that they are not limited thereto. Among these metal compounds according to the present invention, particularly preferred are silver compounds and palladium compounds having a large complex formation constant.

The amount of these metal compounds used varies depending on the kind of the metal compound and the content of hydrogen cyanide in the raw material acetonitrile, but it is usually compared with acetonitrile.
About 0.0001 to 0.01% by weight, preferably about 0.0002 to 0.005% by weight is used. It should be noted that if the amount used is less than this, the removal effect is remarkably reduced, and even if the amount used is greater than this, an increase in the removal effect cannot be expected and at the same time the amount of the porous adsorbent used is significantly increased. There are difficulties.
These metal compounds may be dissolved in acetonitrile uniformly and used as a solution state, or may be dissolved in a small amount of a solvent uniformly mixed with acetonitrile and used,
These metal compounds may be used in a state of being suspended in acetonitrile, and no difference is seen in the effect of removing hydrogen cyanide in any method. The treatment time with these metal compounds, that is, the reaction time between the metal compound and hydrogen cyanide in acetonitrile varies depending on the type of metal element and the method of use, but for example, when the palladium compound is uniformly dissolved in acetonitrile and used as a solution state. Then, the reaction may be performed by stirring for about 30 seconds to 120 minutes, preferably about 5 to 60 minutes. Also, when using silver sulfate suspended in acetonitrile, it is sufficient to stir for about 5 to 60 minutes in the same manner.

The treatment temperature is not particularly limited, and accordingly, heating,
There is no need for cooling or the like, and there is no need to set special conditions such as inert gas replacement. That is, the reaction treatment may be performed in the air at room temperature. Thus, after converting the hydrogen cyanide into a stable metal cyanide complex, the metal cyanide complex is not decomposed by, for example, distilling it at a low temperature and a high degree of vacuum, and the liquid chromatograph containing substantially no hydrogen cyanide. High-purity acetonitrile can be easily obtained, but when trying to obtain the target high-purity acetonitrile without being affected by distillation conditions (temperature, vacuum, etc.), the stable anionic nature of the reaction product It is preferable to distill after adsorbing the metal cyanide complex on the adsorbent. To adsorb and separate the metal cyanide complex from acetonitrile, for example, activated alumina after completion of the reaction with the metal compound,
Treatment may be carried out by contacting with a porous adsorbent such as activated carbon, silica gel, zeolite or ion exchange resin, or treatment with the metal compound according to the present invention in the presence of these porous adsorbents.

When the treatment with the porous adsorbent is carried out after the reaction with the metal compound, even if this is carried out by a batch method in which the porous adsorbent is charged into acetonitrile containing the metal cyanide complex and stirred, This can be carried out by any of the column methods in which acetonitrile containing a metal cyanide complex is passed through a column filled with a hydrophilic adsorbent.
Further, in the case of treating with a metal compound in the presence of a porous adsorbent, even if the porous adsorbent and the metal compound according to the present invention are put into acetonitrile containing hydrogen cyanide at the same time, the former is put first and the latter is put later. However, the latter may be added first, the former may be added later, or a porous adsorbent supporting a metal compound may be used in any method, and any difference in the effect of removing hydrogen cyanide is recognized. Absent.

The amount of the porous adsorbent used varies depending on the type of the porous adsorbent and the amount of the metal cyanide complex.
Usually about 0.1 to 20% by weight, preferably about 1 to 10% by weight with respect to acetonitrile.
It is desirable to stir for about 0.5 to 120 minutes, preferably about 5 to 60 minutes. Speaking of the column method, the treatment flow rate varies depending on the type and amount of the metal compound and the type and amount of the packing material, but for example, when packed with 10 g of activated alumina, 0.
It is preferable to pass the solution at a rate of about 5 to 50 ml / min, and a treatment flow rate of about 10 to 30 ml / min is particularly suitable. As the porous adsorbent, any of those mentioned above can be used, but activated alumina can be particularly preferably used. When an ion exchange resin is used, it is preferable to use a cation exchange resin and an anion exchange resin together.

In the contact treatment with the porous adsorbent, not only metal cyanide complex but also halogen ion, nitrate ion,
Anions such as sulfate ions, perchlorate ions, and acetate ions and excess unreacted metal ions are also adsorbed and removed, and when activated alumina, silica gel, zeolite, etc. are used as the porous adsorbent, water is also adsorbed. Therefore, it is possible to produce high-purity acetonitrile that does not substantially contain hydrogen cyanide only by solid-liquid separation operation, but since a very small amount of non-volatile substances may be mixed from the porous adsorbent, the porous adsorbent It is desirable to remove non-volatile substances by atmospheric distillation or vacuum distillation after the contact treatment with. Distillation conditions and the like may be carried out by the usual method conventionally used for this type of purification method. When the treatment with the porous adsorbent is carried out by the batch method, the solid-liquid separation operation is not always necessary in the distillation.

The method for removing hydrogen cyanide according to the present invention by treating with a metal compound and a porous adsorbent according to the present invention can be applied to any step in the purification of acetonitrile for industrial use into high purity acetonitrile for liquid chromatography. It doesn't matter. That is, it may be any step after purification from industrial acetonitrile to high-purity acetonitrile for liquid chromatography by a known method, or purification to high-purity acetonitrile for liquid chromatography by a known method. By incorporating the method for removing hydrogen cyanide of the present invention into a process for producing acetonitrile for liquid chromatography using industrial acetonitrile as a raw material, hydrogen cyanide contained in the raw material can be easily and substantially completely in a short time and with a small labor. A high-purity acetonitrile for liquid chromatography, which can be removed and contains substantially no hydrogen cyanide, can be obtained.

EXAMPLES The present invention will be described in more detail with reference to examples and reference examples, but the present invention is not limited to these examples and reference examples.

EXAMPLE 1 Palladium chloride was added to 200 ml of acetonitrile having a hydrogen cyanide concentration of 0.1 mmol / liter, and the concentrations thereof were 0, 0.01, 0.015, 0.02, 0.025, 0.03, 0.04 and 0.0, respectively.
Those added at 6, 0.08 and 0.1 mmol / liter were prepared, and these were stirred for 15 minutes to react with each other, and then equally divided into 100 milliliters. Then, 1 g of activated alumina was added to each of the equally divided reaction solutions, and the mixture was stirred for 30 minutes, and then the activated alumina was filtered by suction filtration to obtain a filtrate. Further, activated alumina was not added to each of the other reaction solutions, and the reaction solutions were allowed to stand for 30 minutes. The content of hydrogen cyanide in the obtained filtrate and the reaction solution that had been allowed to stand was measured by the pyridine-pyrazolone method. The result is shown in FIG. From FIG. 1, the concentration of hydrogen cyanide in acetonitrile tends to decrease as the concentration of added palladium chloride increases, and the concentration of hydrogen cyanide remaining in the filtrate when activated alumina coexists is 0.1 mmol of hydrogen cyanide. On the other hand, it was found that the concentration of hydrogen cyanide becomes the lower limit of detection when 0.025 mmol or more of palladium chloride is added. The reaction molar ratio at this time is HCN: Pd =
Since it is 4: 1, hydrogen cyanide in acetonitrile reacts with palladium in the same manner as in an aqueous solution to react with tetracyanopalladium (II) acid ion, Pd (C
It can be seen that N) ₄ ²⁻ is generated. Furthermore, it is found that activated alumina can easily adsorb this complex and accelerate the rate of complex formation, and reduce hydrogen cyanide in acetonitrile to the lower limit of detection in a short time. In addition, pyridine-
The detection limit of the pyrazolone method is 0.05 ppm, and therefore 0 in the figure means that it was 0.05 ppm or less.

Example 2 To 1 liter of industrial acetonitrile containing hydrogen cyanide, 50 mg of palladium nitrate was added and stirred for 15 minutes. Then, 20 g of activated alumina was added, and after stirring for 10 minutes, suction filtration was performed to remove the activated alumina. The filtrate 9
50 ml was distilled under reduced pressure to obtain 800 ml of purified acetonitrile. For industrial acetonitrile, filtrate after treatment with activated alumina and acetonitrile after distillation,
The contents of hydrogen cyanide, palladium, and aluminum and the absorbance in the ultraviolet region at wavelengths of 210 nm and 230 to 240 nm were measured. The results are shown in Table 1. The measurement of palladium and aluminum was carried out by a flameless atomic absorption method with lower detection limits of 1 ppb and 2 ppb, respectively.

[0017]

[Table 1]

Example 3 To 500 ml of industrial acetonitrile containing hydrogen cyanide, the respective metal compounds shown in Table 2 were added in the amounts shown in the table, and the mixture was stirred at room temperature for 30 minutes. Then, the respective porous adsorbents shown in Table 2 were added to these in the amounts shown in the table. At this time, the space in the flask was left in a state where air was present without being replaced with an inert gas. After stirring at room temperature for 15 minutes, the filtrate obtained by suction filtration was distilled under reduced pressure to obtain 400 ml of purified acetonitrile each.
Regarding industrial acetonitrile and purified acetonitrile at this time, hydrogen cyanide content and wavelength 210 nm and 230 to 240 n
The ultraviolet absorbance at m was measured. The results are shown in Table 2.
Shown in.

[0019]

[Table 2]

Example 4 1 liter of industrial acetonitrile containing 10 mg of silver nitrate added thereto was passed through a glass column having a diameter of 2 cm and filled with 10 g of activated alumina at a flow rate of 10 ml / min, and the effluent was discharged at 10
10 fractions of 0 ml each (Fr.1 to Fr.10)
Fractionated into The hydrogen cyanide content in each fraction and the UV absorbance at wavelengths 210 nm and 230 to 240 nm were measured. The results are shown in Table 3.

[0021]

[Table 3]

As is clear from the results of Table 1, Table 2 and Table 3, high-performance liquid chromatograph was obtained by treating hydrogen cyanide-containing acetonitrile with the metal compound according to the present invention and the porous adsorbent by a batch method or a column method. (H
It is understood that hydrogen cyanide can be completely removed (below the detection limit) without adversely affecting other measurement items required for PLC).

Example 5 To 1 liter of industrial acetonitrile containing hydrogen cyanide, 10 ml of acetonitrile in which 100 mg of copper sulfate was dissolved and 20 g of silica gel were simultaneously charged. After stirring at room temperature for 30 minutes, the filtrate obtained by suction filtration was distilled under reduced pressure to obtain 800 ml of purified acetonitrile. The hydrogen cyanide content in this purified product was 0.05 ppm or less.

Example 6 To 500 ml of industrial acetonitrile containing hydrogen cyanide, 20 g of activated carbon was added and stirred for 10 minutes.
20 mg of ferrous ammonium sulfate was added, and the mixture was stirred at room temperature for 30 minutes. The activated carbon was removed by suction filtration, and the obtained filtrate was distilled under reduced pressure to obtain 400 ml of purified acetonitrile. The hydrogen cyanide content in this purified product was 0.05 ppm or less.

Reference Example Example Applied to HPLC Analysis Acetonitrile and a phosphate buffer of 50 mmol / liter were mixed at a volume ratio of 55:45 to prepare an eluent for HPLC analysis. At this time, as the acetonitrile, a high-purity product obtained by purifying hydrogen cyanide obtained in the present invention to below the lower limit of detection and a commercially available HPL containing a trace amount of hydrogen cyanide
Using acetonitrile for C, pesticide thiuram was analyzed by HPLC at a measurement wavelength of 210 nm and 272 nm by a conventional method. The result is shown in FIG. A- (1) and A- in FIG.
As is apparent from (2), when the eluent prepared with the high-purity acetonitrile obtained by the method of the present invention is used, only the main peak of thiuram is clearly recorded on the chromatogram. On the other hand, as is clear from B- (1) and B- (2) in FIG. 2, when an eluent prepared with a commercially available acetonitrile for HPLC is used, the reaction product of thiuram and hydrogen cyanide is shown in the chromatogram. The peaks for monothiuram and dimethyldithiocarbamic acid were recorded, indicating that the analysis of thiuram was significantly disturbed. From the above results, it is clear that acetonitrile obtained by purification by the method of the present invention is highly purified and is very useful as a reagent for liquid chromatography.

[0026]

[Effects] As described above, the present invention has an excellent effect in removing a very small amount of hydrogen cyanide in the order of ppm existing in acetonitrile, and according to the present invention, it is extremely difficult to completely remove hydrogen cyanide conventionally. Since it is possible to remove hydrogen cyanide in acetonitrile, which has been difficult, practically completely by an industrially simple and inexpensive method without requiring special equipment, a liquid chromatograph widely used in various fields in recent years. In analysis, it greatly contributes to the improvement of analysis sensitivity and accuracy.

[Brief description of drawings]

1 shows the results obtained in Example 1,-●-
Shows the results of measuring the hydrogen cyanide concentration in Example 1 when activated alumina was added to the reaction solution, and -O- when the activated alumina was not added to the reaction solution.
However, the vertical axis represents the hydrogen cyanide concentration (ppm), and the horizontal axis represents the palladium chloride concentration (mmol / liter).

FIG. 2 shows the results obtained in Reference Example, A is a liquid chromatogram when high-purity acetonitrile obtained by the method of the present invention was used for the analysis of thiuram, and A-
(1) is a chromatogram measured at 272 nm and A- (2) at 210 nm. B shows the result when using acetonitrile for commercial HPLC, B- (1) is 272 nm, B
-(2) is the chromatogram measured at 210 nm

Claims (8)

[Claims] 1. Acetonitrile containing hydrogen cyanide is vanadium, chromium, manganese, thallium, lead, periodic table I
Hydrogen cyanide characterized by being treated with a compound of a metal element selected from the group consisting of b-groups, IIb-groups and VIII-groups (hereinafter abbreviated as "metal compound according to the invention") and then distilled. Method for producing high-purity acetonitrile for liquid chromatographs that does not contain specially. 2. The metal compound according to the present invention is vanadium,
Chromium, manganese, thallium, lead, periodic table Ib group, II
The production method according to claim 1, which is one or more kinds of halides, nitrates, sulfates, perchlorates or carboxylates of metal elements selected from the group consisting of Group b and Group VIII. 3. A method for producing high-purity acetonitrile for liquid chromatography, which is substantially free of hydrogen cyanide, characterized in that acetonitrile containing hydrogen cyanide is treated with the metal compound according to the present invention and a porous adsorbent, and then distilled. . 4. The metal compound according to the present invention is vanadium,
Chromium, manganese, thallium, lead, periodic table Ib group, II
The production method according to claim 3, which is one or more kinds of halides, nitrates, sulfates, perchlorates or carboxylates of metal elements selected from the group consisting of Group b and Group VIII. 5. The method according to claim 3, wherein the porous adsorbent is at least one selected from the group consisting of activated alumina, activated carbon, silica gel, zeolite and ion exchange resins. 6. The production method according to claim 3, wherein the hydrogen cyanide-containing acetonitrile is treated with the metal compound according to the present invention and then contacted with a porous adsorbent. 7. The production method according to claim 3, wherein the hydrogen cyanide-containing acetonitrile is treated with the metal compound according to the present invention in the presence of a porous adsorbent. 8. The production method according to claim 3, wherein the hydrogen cyanide-containing acetonitrile is treated with a porous adsorbent carrying the metal compound according to the present invention.