Method for purifying trialkylamine and method for producing trialkylamine

Abstract

A purpose of the present disclosure is to provide a novel method for lowering the concentration of dimethylamine, diethylamine, ethylpropylamine, and ethylisopropylamine in crude trialkylamine. The present disclosure is a method for purifying trialkylamine characterized by bringing crude trialkylamine including at least one selected from the group consisting of dimethylamine, diethylamine, ethylpropylamine, and ethylisopropylamine into contact with a zeolite and lowering the concentration of at least one selected from the group consisting of dimethylamine, diethylamine, ethylpropylamine, and ethylisopropylamine in the crude trialkylamine from that before the zeolite contact.

Description

[Technical Field]

[0001] The present disclosure relates to a method for purifying trialkylamines using zeolites, a method for producing trialkylamines, and compositions thereof, particularly to a method for purifying triethylamine, a method for producing triethylamine, and a composition containing triethylamine, as well as a method for purifying trimethylamine, a method for producing trimethylamine, and a composition containing trimethylamine. [Background technology]

[0002] Crude triethylamine, an organic amine, may contain impurities such as diethylamine. In pharmaceutical manufacturing processes and semiconductor device manufacturing processes, it is preferable that the raw materials used be highly pure. As a method for purifying triethylamine, a method has been reported in which the impurities are amidated using an amidating agent such as acetyl chloride to convert them into a compound that is easily removed, and the amidated product is extracted with hot water and then rectified (for example, Patent Document 1).

[0003] The method disclosed in Patent Document 1 requires multiple operations and steps, such as amidating and extracting impurities, followed by rectification, and there is a demand for a simpler method for purifying triethylamine that does not require the use of additives such as an amidating agent.

[0004] Furthermore, crude trimethylamine, another example of an organic amine, may contain approximately 1,000 ppm by volume of dimethylamine as an impurity. Trimethylamine and dimethylamine have similar vapor pressures and form an azeotrope, so distillation can only reduce the dimethylamine concentration to approximately 400 to 500 ppm by volume.

[0005] In recent years, a method using synthetic zeolite has been proposed as a method for removing impurities contained in crude organic amines. Patent Document 2 discloses a purification device that uses synthetic zeolite with pores having an average diameter of 0.3 nm or 0.4 nm to remove low-boiling-point impurities contained in monomethylamine. Examples of the low-boiling-point impurities to be removed include hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, and methane. Patent Document 2 also discloses the use of synthetic zeolite with pores having an average diameter of 0.5 nm to adsorb moisture and hydrocarbons.

[0006] Patent Document 3 discloses a method for purifying trimethylamine, in which water and ammonia are removed from a trimethylamine-containing gas using 3A or 4A zeolite, and monomethylamine and nitrogen are removed using 5A zeolite. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 53-015045 (Patent No. 934266) [Patent Document 2] JP 2016-150926 A (Patent No. 6441116 A) [Patent Document 3] U.S. Patent No. 8,664,446 Summary of the Invention [Problem to be solved by the invention]

[0008] However, although Patent Document 3 discloses a method for removing monomethylamine using synthetic zeolite, it does not disclose that diethylamine, ethylpropylamine, ethylisopropylamine, or dimethylamine can be removed using synthetic zeolite. Therefore, it has not been known until now that diethylamine, ethylpropylamine, ethylisopropylamine, or dimethylamine can be removed.

[0009] In view of the above problems, an object of the present disclosure is to provide a novel method for reducing the concentrations of dimethylamine, diethylamine, ethylpropylamine, and ethylisopropylamine in crude trialkylamine. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have found that the concentrations of dimethylamine, diethylamine, ethylpropylamine, and ethylisopropylamine in crude trialkylamine containing impurities can be reduced by contacting the crude trialkylamine with a zeolite, and have thus completed the present disclosure.

[0011] Specifically, the first method for purifying a trialkylamine according to the present disclosure is characterized in that a crude trialkylamine containing at least one impurity selected from the group consisting of diethylamine, ethylpropylamine, and ethylisopropylamine is contacted with a zeolite, and the concentration of at least one impurity selected from the group consisting of diethylamine, ethylpropylamine, and ethylisopropylamine in the crude trialkylamine is reduced compared to the concentration before contact with the zeolite. According to the first method for purifying trialkylamine of the present disclosure, diethylamine, ethylpropylamine, and ethylisopropylamine can be removed by a simple operation without requiring a complicated process using additives, thereby increasing the purity of the trialkylamine.

[0012] The second method for purifying trialkylamine according to the present disclosure is characterized in that crude trialkylamine containing at least dimethylamine as an impurity is brought into contact with a zeolite having pores with a diameter of 0.2 to 0.6 nm, and the concentration of dimethylamine in the crude trialkylamine is reduced below that before contact with the zeolite. According to the second method for purifying trialkylamine of the present disclosure, dimethylamine can be removed by a simple operation without requiring a complicated process using additives, thereby increasing the purity of trialkylamine.

[0013] The method for producing a trialkylamine according to the present disclosure is characterized by carrying out a step of synthesizing a crude trialkylamine and a step of purifying the crude trialkylamine using the above-described purification method. According to the method for producing trialkylamine of the present disclosure, highly pure trialkylamine can be produced by a simple operation.

[0014] The first composition of the present disclosure is characterized by containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 150 GC area ppm or less of diethylamine. The second composition of the present disclosure is characterized by containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 150 GC area ppm or less of ethylpropylamine. A third composition of the present disclosure is characterized by containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 20 GC area ppm or less of ethylisopropylamine. The GC area % and GC area ppm are values ​​that indicate the ratio of the area of ​​the target component to the total area of ​​peaks obtained by GC (gas chromatograph). A fourth composition of the present disclosure is characterized by containing 99.9% by weight or more of trialkylamine and 50 ppm by volume or more and 400 ppm by volume or less of dimethylamine. A fifth composition of the present disclosure is characterized by containing 99.9% by weight or more of trialkylamine and 10 ppm by volume or less of dimethylamine. The first to fifth compositions of the present disclosure can also be used in pharmaceutical manufacturing processes and semiconductor manufacturing processes, where high purity of raw materials is required. [Effects of the Invention]

[0015] The method for purifying trialkylamine disclosed herein makes it possible to remove impurities from crude trialkylamine through a simple operation without using any additives, thereby increasing the concentration of trialkylamine, and to supply extremely pure trialkylamine that can be used in pharmaceutical manufacturing processes and semiconductor manufacturing processes. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the present disclosure is not limited to these specific details. Various modifications can be made within the scope of the gist of the present disclosure.

[0017] <First method for purifying trialkylamine> The first method for purifying a trialkylamine according to the present disclosure is characterized in that a crude trialkylamine containing at least one impurity selected from the group consisting of diethylamine, ethylpropylamine, and ethylisopropylamine is contacted with a zeolite, and the concentration of the at least one impurity selected from the group consisting of diethylamine, ethylpropylamine, and ethylisopropylamine in the crude trialkylamine is reduced compared to the concentration before contact with the zeolite.

[0018] The zeolite used in the purification method of the present disclosure is a crystalline aluminosilicate, also known as a molecular sieve, and is classified into synthetic zeolite, artificial zeolite, and natural zeolite. In the purification method of the present disclosure, any of synthetic zeolite, artificial zeolite, and natural zeolite can be used, but it is preferable to use synthetic zeolite with high purity. In the present disclosure, the zeolite preferably has pores with a diameter of 0.2 to 1.2 nm or 3 to 12 Å. If the pore diameter of the zeolite is outside the above range, the effect of reducing impurities in crude triethylamine may be reduced.

[0019] Suitable synthetic zeolites having pores with diameters of 0.2 to 1.2 nm include 3A, 4A, 5A, and 13X synthetic zeolites. The "A" in 3A, 4A, and 5A synthetic zeolites stands for Å (angstrom). The pores in 13X synthetic zeolites have diameters of 1.0 nm or 10 Å. Synthetic zeolite type 3A has a pore diameter of 0.3 nm and can pass molecules up to 0.3 nm in diameter. Synthetic zeolite type 4A has a pore diameter of 0.35 nm, but at normal operating temperatures, due to the stretching and kinetic energy of molecules entering the cavity, it can pass molecules up to 0.4 nm in diameter. Synthetic zeolite type 5A has a pore diameter of 0.42 nm and can pass molecules up to 0.5 nm in diameter for the same reason. Synthetic zeolite type 13X has a pore diameter of 1.0 nm and can pass molecules up to 1.0 nm in diameter. Here, the range of diameters (adsorption apertures) of molecules that can pass through 3A, 4A, 5A, or 13X synthetic zeolites will be specified below. 3A type 0.3nm or less 4A type 0.4nm or less 5A type 0.5nm or less 13X type 1.0nm or less

[0020] Specific examples of synthetic zeolites of type 3A, type 4A, type 5A, and type 13X include molecular sieve 3A, molecular sieve 4A, and molecular sieve 5A manufactured by Union Showa Co., Ltd. Molecular sieve 13X: Molecular sieves 3A, Molecular sieves 4A, Molecular sieves 5A, Molecular sieves 13X, etc. manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. may be used.

[0021] In the present disclosure, the zeolite is more preferably a zeolite having pores with a diameter of 0.8 to 1.2 nm, and even more preferably a zeolite having pores with a diameter of 0.9 to 1.1 nm. When the pore diameter of the zeolite is 0.8 to 1.2 nm, the effect of reducing diethylamine, ethylpropylamine, and ethylisopropylamine in the crude trialkylamine is high. In the present disclosure, the zeolite is particularly preferably a 13X-type synthetic zeolite. The shape of the zeolite used in the purification method of the present disclosure is not particularly limited, and may be any of beads, pellets, powder, etc., but beads and pellets are preferred as they are easy to use in chemical industrial plants.

[0022] The zeolite used in the purification method of the present disclosure can be a purchased product and used as is, but it is preferable to dry it before contacting it with a crude trialkylamine. The drying conditions are preferably 100°C or higher for 1 hour or more, and more preferably 100 to 150°C for 1 to 2 hours.

[0023] The method for contacting the crude trialkylamine with the zeolite is not particularly limited, and examples thereof include a method in which the zeolite is added to a container or the like for storing the crude trialkylamine and left to stand (immersion method), a method in which the zeolite is packed into a column, a packed tower, or the like, and the crude trialkylamine is passed through the column or packed tower to be brought into flow contact with the zeolite (column method), etc. In the purification method of the present disclosure, the immersion method is preferred because it is simple and convenient.

[0024] The trialkylamine may be an amine in which the three alkyl groups have 1 to 4 carbon atoms. Examples of the alkyl groups having 1 to 4 carbon atoms in the trialkylamine include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a butyl group, an isobutyl group, and a t-butyl group. The three alkyl groups in the trialkylamine may be different groups or the same group, but it is preferable that they are all the same group. The trialkylamines include trimethylamine, triethylamine, tri-n-propylamine, triisopropylamine, tributylamine, triisobutylamine, and tri-t-butylamine.

[0025] The conditions for contacting the crude trialkylamine with the zeolite are not particularly limited and are, for example, 0 to 80°C and 30 seconds to 24 hours. When the crude trialkylamine is crude triethylamine, the temperature is preferably 10 to 40°C. Crude triethylamine is a liquid at room temperature and normal pressure, and it is more preferable to contact the liquid crude triethylamine with the zeolite under conditions of 10 to 40°C.

[0026] The first trialkylamine purification method of the present disclosure is suitable for purifying triethylamine. Crude triethylamine, which is one of the targets of purification by the purification method of the present disclosure, is triethylamine containing at least one of diethylamine, ethylpropylamine, and ethylisopropylamine as an impurity. The crude triethylamine may be obtained by synthesizing triethylamine using a conventionally known method, or may be purchased; the method of obtaining the crude triethylamine is not particularly limited. Examples of methods for synthesizing triethylamine include the acetaldehyde method, in which acetaldehyde, ammonia, and hydrogen are reacted using a catalyst, and the ethyl alcohol method, in which ethyl alcohol is used instead of acetaldehyde.

[0027] The crude trialkylamine may contain impurities other than diethylamine, ethylpropylamine, and ethylisopropylamine, and examples of the other impurities include monoethylamine, acetaldehyde, ethyl alcohol, hydrogen, oxygen, nitrogen, carbon monoxide, carbon dioxide, methane, ammonia, and water.

[0028] The crude trialkylamine preferably contains 99 GC area % or more of trialkylamine, more preferably 99.5 GC area % or more. The crude trialkylamine contains at least diethylamine as an impurity, preferably more than 150 ppm by GC area of ​​diethylamine, more preferably more than 150 ppm by GC area and not more than 250 ppm by GC area. The crude trialkylamine preferably contains more than 150 ppm by area GC of ethylpropylamine or more than 20 ppm by area GC of ethylisopropylamine, more preferably more than 150 ppm by area GC and up to 250 ppm by area GC of ethylpropylamine, and more preferably more than 20 ppm by area GC and up to 30 ppm by area GC of ethylisopropylamine. When the concentrations of diethylamine, ethylpropylamine, and ethylisopropylamine in the crude trialkylamine are greater than the above values, it is possible to remove these impurities using a method such as distillation before treating the crude trialkylamine with the purification method of the present disclosure.

[0029] In the purification method of the present disclosure, crude trialkylamine is contacted with a zeolite, and the concentration of at least one of diethylamine, ethylpropylamine, and ethylisopropylamine contained in the crude trialkylamine can be reduced compared to before contact with the zeolite.

[0030] In the purification method of the present disclosure, the preferred concentrations of each component after contact with the zeolite are as follows: The purity of the trialkylamine is preferably 99.9 GC area % or more, and more preferably 99.95 GC area % or more. The diethylamine content in the trialkylamine is preferably 150 GC area ppm or less, more preferably 100 GC area ppm or less. The content of ethylpropylamine in the trialkylamine is preferably 150 GC area ppm or less, more preferably 100 GC area ppm or less. The ethylisopropylamine content in the trialkylamine is preferably 20 GC area ppm or less, more preferably 15 GC area ppm or less. The purification method of the present disclosure is also capable of reducing the concentrations of impurities other than diethylamine, ethylpropylamine, and ethylisopropylamine.

[0031] <Second method for purifying trialkylamine> The second method for purifying trialkylamines will be described in detail below. Only the differences from the first method for purifying trialkylamines will be described here, and explanations of the common points will be omitted.

[0032] The second method for purifying trialkylamine according to the present disclosure is characterized in that crude trialkylamine containing at least dimethylamine as an impurity is brought into contact with a zeolite having pores with a diameter of 0.2 to 0.6 nm, and the concentration of dimethylamine in the crude trialkylamine is reduced below that before contact with the zeolite. The second bird Alkyl In the amine purification method, the zeolite used must have pores with a diameter of 0.2 to 0.6 nm. If the pore diameter of the zeolite is less than 0.2 nm or more than 0.6 nm, the effect of reducing the dimethylamine concentration in the crude trialkylamine will be reduced. As the synthetic zeolite having pores with a diameter of 0.2 to 0.6 nm, 3A, 4A, or 5A synthetic zeolite is preferred.

[0033] The zeolite used in the purification method of the present disclosure can be purchased and used as is, but it is preferable to dry it before contacting it with crude trialkylamine. The drying conditions are preferably 1 kPa or less, 150°C or higher, and 30 minutes or more, more preferably 1 kPa or less, 150 to 200°C, and 30 to 60 minutes.

[0034] The method for contacting the crude trialkylamine with the zeolite is not particularly limited, but the column method is preferred because it is highly effective in removing the impurity dimethylamine and can be purified in a short time. However, when the concentration of dimethylamine in the crude trialkylamine is high, it is preferable to use a column method before the column method. immersion The dimethylamine concentration is reduced to a certain level before the column method is performed. immersion The method and the column method can also be combined.

[0035] In particular, when the crude trialkylamine is crude trimethylamine, the temperature and pressure conditions for flow-contacting the crude trimethylamine with the zeolite are preferably 20 to 30°C and atmospheric pressure or higher. The pressure conditions are more preferably 150 to 200 kPa. The time for flow-contacting the crude trimethylamine with the zeolite is preferably 50 to 200 seconds. If the time is less than 50 seconds, dimethylamine may not be sufficiently removed. On the other hand, flow-contacting for more than 200 seconds may not be effective in removing dimethylamine. The time for flow-contacting the crude trimethylamine with the zeolite is more preferably 100 to 150 seconds. The second trialkylamine purification method of the present disclosure is suitable for purifying trimethylamine.

[0036] In the second method for purifying trialkylamine, a preferred embodiment is to flow and contact crude trimethylamine in a gaseous state with zeolite at 20 to 30° C. and atmospheric pressure or higher for 100 seconds or longer.

[0037] When crude trimethylamine is brought into contact with the zeolite through flow, the linear velocity of the crude trimethylamine is preferably 0.001 to 0.1 m / sec, more preferably 0.01 to 0.1 m / sec.

[0038] Crude trimethylamine, which is one of the targets of purification by the purification method of the present disclosure, is trimethylamine containing at least dimethylamine as an impurity. The crude trimethylamine may be obtained by synthesizing trimethylamine by a conventionally known method (e.g., the method described in JP-A-58-049340) or may be purchased, and the method of obtaining the crude trimethylamine is not particularly limited.

[0039] In the second purification method, the crude trialkylamine is purified by purifying the trialkylamine to 98% by weight. End It is preferable that the content be 99% by weight or more, more preferable that the content be 99.9% by weight or more. The concentration of dimethylamine in the crude trialkylamine is preferably 500 to 1500 ppm by volume. If the concentration of dimethylamine in the crude trialkylamine is higher than the above value, the dimethylamine may be removed by a method such as distillation before treatment with the purification method of the present disclosure, or the above-mentioned immersion It is conceivable to combine the column method with the column method.

[0040] Dimethylamine in crude trialkylamine is unstable, and its concentration in the gas phase is not stable. In a preferred embodiment, the crude trialkylamine purified by the purification method of the present disclosure may be in the form of a liquid or gas. When the crude trialkylamine is crude trimethylamine, gas is preferred because purification can be carried out at room temperature and atmospheric pressure.

[0041] In the second purification method of the present disclosure, the dimethylamine concentration in the crude trialkylamine is preferably reduced to 400 ppm by volume or less. More preferably, it is 300 ppm by volume or less. The lower limit of the dimethylamine concentration in the trialkylamine obtained by the purification method of the present disclosure is, for example, 50 ppm by volume or 90 ppm by volume. By combining the second purification method of the present disclosure with various purification methods, such as known distillation techniques such as simple distillation, continuous distillation, and precision distillation, it is possible to significantly reduce the dimethylamine concentration in the trialkylamine to 10 ppm by volume or less. It is also possible to reduce the dimethylamine concentration below the detection limit, in which case the lower limit of the dimethylamine concentration in the trialkylamine is, for example, an amount exceeding 0 ppm by volume. The purification method of the present disclosure can produce the high-purity trialkylamine described above. Such high-purity trialkylamine is suitable for applications such as dry etching of silicon oxide.

[0042] The present disclosure also provides a method for producing a trialkylamine, comprising the steps of synthesizing a crude trialkylamine and purifying the crude trialkylamine using the first trialkylamine purification method and the second trialkylamine purification method. In the crude trialkylamine purification step, both the first trialkylamine purification method and the second trialkylamine purification method may be performed. The step of synthesizing a crude trialkylamine can be carried out by the methods described above for the first method for purifying a trialkylamine and the second method for purifying a trialkylamine, but is not limited to these methods. The step of purifying the crude trialkylamine can be carried out using the same materials, operations and procedures as those described above for the first method for purifying a trialkylamine and the second method for purifying a trialkylamine. The trialkylamine obtained by the production method of the present disclosure may have a concentration of at least one of dimethylamine, diethylamine, ethylpropylamine, and ethylisopropylamine that is reduced compared to the crude trialkylamine before contact with the zeolite, and the concentration of each component is as described above for the purification method.

[0043] The first composition of the present disclosure is a composition containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 150 GC area ppm or less of diethylamine. Preferably, the first composition contains diethylamine in an amount of 1 GC area ppm or more and 100 GC area ppm or less. The second composition of the present disclosure is a composition containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 150 GC area ppm or less of ethylpropylamine. Preferably, the second composition contains 1 GC area ppm or more and 100 GC area ppm or less of ethylpropylamine. The third composition of the present disclosure is a composition containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 20 GC area ppm or less of ethylisopropylamine. Preferably, the content of ethylisopropylamine in the third composition is 1 GC area ppm or more and 15 GC area ppm or less. A fourth composition of the present disclosure is a composition containing 99.9% by weight or more of trialkylamine and 50 ppm by volume or more and 400 ppm by volume or less of dimethylamine. In the fourth composition, the content of dimethylamine in the composition is preferably 90 ppm by volume or more and 300 ppm by volume or less. A fifth composition of the present disclosure is a composition containing 99.9% by weight or more of trialkylamine and 10 ppm by volume or less of dimethylamine. Preferably, the content of dimethylamine in the fifth composition is greater than 0 ppm by volume and less than 10 ppm by volume. These first to fifth compositions can be obtained by the above-mentioned method for producing trialkylamine. [Example]

[0044] Examples that more specifically describe embodiments of the present disclosure are provided below. However, the present disclosure is not limited to these examples. The molecular sieves 3A, 4A, 5A, and 13X used in the examples correspond to synthetic zeolites of type 3A, type 4A, type 5A, and type 13X, respectively.

[0045] (Purification of crude triethylamine) The crude triethylamine used in this example was synthesized with reference to a conventional production method. The purity of triethylamine in the crude triethylamine obtained by synthesis was 99.89 GC area%. The crude triethylamine also contained impurities such as diethylamine (155.9 GC area ppm), ethylpropylamine (179.3 GC area ppm), and ethylisopropylamine (20.8 GC area ppm). The concentrations of triethylamine and impurities were analyzed using a gas chromatograph analyzer under the following conditions. Taking the relative retention time of triethylamine as 1.00, the total area of ​​the gas chromatography chart for components with a relative retention time of 1.85 or less was taken as 100% GC area, and the GC area % concentration or GC area ppm concentration of each component was calculated. The relative retention times of diethylamine, ethylpropylamine, and ethylisopropylamine were 0.69, 0.95, and 0.84, respectively. (Gas chromatography analysis conditions) Measurement sample: Liquid crude triethylamine 1 μL Equipment: GC-2014 (Shimadzu Corporation) Detector: Flame ionization detector (FID) Column used: Inertcap for Amines, length 60 m, inner diameter 0.32 mm (GL Sciences, Inc.) Analysis conditions: injection temperature 200°C, detection temperature 250°C Carrier gas: Helium Column flow rate: 2.99 mL / min Column temperature: 50°C for 15 minutes, increase temperature to 200°C at 10°C / min, hold at 200°C for 5 minutes, increase temperature to 250°C at 10°C / min, hold at 250°C for 5 minutes

[0046] [Example 1] 10 mL of crude triethylamine was placed in a glass container, and 5 g of molecular sieves 3A (pore size 0.3 nm, manufactured by Union Showa Co., Ltd.) that had been dried by heating in a drying oven at 120°C for 1 hour was added to the glass container and immersed in the crude triethylamine. The contents were then left to stand for 1 minute. The concentrations of triethylamine and impurities obtained after the immersion treatment were then analyzed using a gas chromatograph. The results are shown in Table 1.

[0047] [Example 2] The immersion treatment was carried out in the same manner as in Example 1, except that molecular sieve 3A was changed to molecular sieve 4A (pore diameter 0.35 nm, manufactured by Union Showa Co., Ltd.), and the concentrations of triethylamine and impurities were analyzed. The results are shown in Table 1.

[0048] [Example 3] The immersion treatment was carried out in the same manner as in Example 1, except that molecular sieve 3A was changed to molecular sieve 5A (pore diameter 0.42 nm, manufactured by Union Showa Co., Ltd.), and the concentrations of triethylamine and impurities were analyzed. The results are shown in Table 1.

[0049] [Example 4] The immersion treatment was carried out in the same manner as in Example 1, except that Molecular Sieve 3A was replaced with Molecular Sieve 13X (pore diameter 1.0 nm, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and the concentrations of triethylamine and impurities were analyzed. The results are shown in Table 1.

[0050] [Comparative Example 1] The concentrations of crude triethylamine and impurities were analyzed using a gas chromatograph without immersion treatment. The results are shown in Table 1.

[0051] [Table 1]

[0052] As is clear from the results in Table 1, in Examples 1 to 4, the concentrations of triethylamine after the immersion treatment were higher and the concentrations of diethylamine, ethylpropylamine, and ethylisopropylamine were lower than in Comparative Example 1, which did not employ the immersion treatment. Note that in Example 4, which used molecular sieve 13X as the zeolite, the concentrations of diethylamine and ethylpropylamine were less than half of those in Comparative Example 1, and the concentration of ethylisopropylamine was lower by 30% or more.

[0053] (Purification of crude trimethylamine) The crude trimethylamine used in this example was synthesized with reference to a conventional manufacturing method. The trimethylamine contained impurities in the gas phase, such as 500 to 2000 volume ppm of dimethylamine and 100 to 1000 volume ppm of water. The impurity concentrations were analyzed using a gas chromatograph analyzer (GC-2014, manufactured by Shimadzu Corporation, detector: FID).

[0054] [Example 5] A packed column measuring 10.6 mm in diameter and 0.1 m in length was packed with molecular sieve 3A (pore size: 0.3 nm, manufactured by Union Showa Co., Ltd.) as zeolite, and dried under reduced pressure at 150°C for 30 minutes. After that, crude trimethylamine was passed through the column at a linear velocity of 0.02 m / sec (contact time with the zeolite: 5 seconds). Trimethylamine was collected from the outlet of the packed column and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0055] [Example 6] Except for changing the length of the packed tower to 1 m, crude trimethylamine was passed through (contact time with zeolite: 50 seconds) in the same manner as in Example 5, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0056] [Example 7] The crude trimethylamine was passed through in the same manner as in Example 6 (contact time with zeolite: 100 seconds), except that the number of packed towers was changed to two, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0057] [Example 8] The crude trimethylamine was passed through in the same manner as in Example 6 (contact time with zeolite: 150 seconds), except that the number of packed towers was changed to 3. The dimethylamine concentration was analyzed. The results are shown in Table 2.

[0058] [Example 9] Except for changing the zeolite to molecular sieve 4A (pore size 0.35 nm, manufactured by Union Showa Co., Ltd.), crude trimethylamine was passed through (contact time with zeolite: 5 seconds) in the same manner as in Example 5, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0059] [Example 10] Except for changing the length of the packed tower to 1 m, crude trimethylamine was passed through in the same manner as in Example 9 (contact time with zeolite: 50 seconds), and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0060] [Example 11] The crude trimethylamine was passed through in the same manner as in Example 10 (contact time with zeolite: 100 seconds), except that the number of packed towers was changed to two, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0061] [Example 12] The crude trimethylamine was passed through in the same manner as in Example 10 (contact time with zeolite: 150 seconds), except that the number of packed towers was changed to 3. The dimethylamine concentration was analyzed. The results are shown in Table 2.

[0062] [Example 13] Except for changing the zeolite to Molecular Sieve 5A (pore size 0.42 nm, manufactured by Union Showa Co., Ltd.), crude trimethylamine was passed through (contact time with zeolite: 5 seconds) in the same manner as in Example 5, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0063] [Example 14] The crude trimethylamine was passed through the packed column (contact time with the zeolite: 50 seconds) in the same manner as in Example 13, except that the length of the packed column was changed to 1 m, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0064] [Example 15] The crude trimethylamine was passed through in the same manner as in Example 14 (contact time with zeolite: 100 seconds), except that the number of packed towers was changed to two, and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0065] [Example 16] The crude trimethylamine was passed through in the same manner as in Example 14 (contact time with zeolite: 150 seconds), except that the number of packed towers was changed to 3. The dimethylamine concentration was analyzed. The results are shown in Table 2.

[0066] Comparative Example 2 Except for not packing the zeolite into the packed column, crude trimethylamine was passed through and the dimethylamine concentration was analyzed in the same manner as in Example 5. The results are shown in Table 2.

[0067] Comparative Example 3 The crude trimethylamine was passed through the column (contact time with the zeolite: 5 seconds) in the same manner as in Example 5, except that the zeolite was changed to molecular sieve 13X (pore size: 1.0 nm, manufactured by Union Showa Co., Ltd.), and the dimethylamine concentration was analyzed. The results are shown in Table 2.

[0068] Comparative Example 4 The crude trimethylamine was refluxed for 72 hours using a 20-plate column, after which 30% by weight of the charged amount of trimethylamine was purged from the top of the column at a reflux ratio of 200, and the dimethylamine concentration in the liquid trimethylamine was analyzed. The results are shown in Table 2.

[0069] [Table 2]

[0070] As is clear from the results in Table 2, in Examples 5 to 16, the concentration of dimethylamine after purification was significantly lower than in Comparative Example 2, in which no packing was used. In Examples 6 to 8, 10 to 12, and 14 to 16, in which the contact time with zeolite was 50 seconds or more, the dimethylamine concentration was lower than in Comparative Example 4, in which distillation was performed. In Examples 7 to 8, 11 to 12, and 15 to 16, in which the contact time with zeolite was 100 seconds or more, the dimethylamine concentration was less than half that of Comparative Example 4. In Comparative Example 3, in which molecular sieve 13X was used as the zeolite, the dimethylamine concentration was almost the same as in Comparative Example 2, in which no packing was used.

Claims

1. a crude trialkylamine containing at least one impurity selected from the group consisting of diethylamine, ethylpropylamine, and ethylisopropylamine is contacted with a zeolite, and the concentration of at least one impurity selected from the group consisting of diethylamine, ethylpropylamine, and ethylisopropylamine in the crude trialkylamine is reduced compared to before contact with the zeolite; The method for purifying a trialkylamine, wherein the purity of the crude trialkylamine is 99 GC area % or more.

2. 2. The method for purifying a trialkylamine according to claim 1, wherein the purity of the trialkylamine after contact with the zeolite is 99.9 GC area % or more.

3. The crude trialkylamine contains at least diethylamine as an impurity, 3. The method for purifying a trialkylamine according to claim 1, wherein the amount of diethylamine in the trialkylamine after contact with the zeolite is 150 GC area ppm or less.

4. The crude trialkylamine contains at least diethylamine as an impurity, 4. The method for purifying a trialkylamine according to claim 1, wherein the amount of diethylamine in the trialkylamine after contact with the zeolite is 100 GC area ppm or less.

5. 5. The method for purifying a trialkylamine according to claim 3, wherein the crude trialkylamine contains diethylamine in an amount of more than 150 ppm by GC area.

6. The method for purifying a trialkylamine according to any one of claims 1 to 5, wherein the crude trialkylamine contains ethylpropylamine at more than 150 GC area ppm or ethylisopropylamine at more than 20 GC area ppm.

7. The method for purifying a trialkylamine according to any one of claims 1 to 6, characterized in that the zeolite is dried at 100°C or higher for 1 hour or longer before being contacted with the crude trialkylamine.

8. 8. The method for purifying a trialkylamine according to claim 1, wherein all three alkyl groups of the trialkylamine are the same group.

9. 9. The method for purifying a trialkylamine according to claim 1, wherein the trialkylamine is triethylamine.

10. 10. The method for purifying a trialkylamine according to claim 9, wherein crude triethylamine in a liquid state is contacted with the zeolite at a temperature of 10° C. or higher and 40° C. or lower.

11. The method for purifying a trialkylamine according to any one of claims 1 to 10, wherein the zeolite has pores with a diameter of 0.8 to 1.2 nm.

12. a crude trialkylamine (excluding crude trimethylamine) containing at least dimethylamine as an impurity is contacted with a zeolite having pores with a diameter of 0.2 to 0.6 nm, thereby reducing the concentration of dimethylamine in the crude trialkylamine compared to before contact with the zeolite; A method for purifying trialkylamines, characterized in that the crude trialkylamines contain 98% by weight or more of trialkylamines (excluding trimethylamine).

13. 13. The method for purifying trialkylamine according to claim 12, wherein the concentration of dimethylamine in the crude trialkylamine is reduced to 400 ppm by volume or less.

14. 14. The method for purifying a trialkylamine according to claim 12 or 13, wherein the zeolite is dried under conditions of 1 kPa or less and 150° C. or higher for 30 minutes or longer before contacting the crude trialkylamine.

15. The method for purifying a trialkylamine according to any one of claims 12 to 14, wherein all three alkyl groups of the trialkylamine are the same group.

16. 16. The method for purifying a trialkylamine according to claim 12, wherein the concentration of dimethylamine in the crude trialkylamine before contact with the zeolite is 500 to 1500 ppm by volume.

17. The method for purifying a trialkylamine according to any one of claims 12 to 16, wherein the crude trialkylamine is contacted with the zeolite to reduce the dimethylamine concentration, and then distilled.

18. A method for purifying a trialkylamine described in any one of claims 1 to 11, wherein the trialkylamine purified by the purification method is a composition characterized by containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 150 GC area ppm or less of diethylamine.

19. A method for purifying a trialkylamine described in any one of claims 1 to 11, wherein the trialkylamine purified by the purification method is a composition characterized by containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 150 GC area ppm or less of ethylpropylamine.

20. A method for purifying a trialkylamine described in any one of claims 1 to 11, wherein the trialkylamine purified by the purification method is a composition characterized by containing 99.9 GC area % or more of trialkylamine and 1 GC area ppm or more and 20 GC area ppm or less of ethylisopropylamine.

21. A method for purifying a trialkylamine according to any one of claims 12 to 17, wherein the trialkylamine purified by the purification method is a composition containing 99.9% by weight or more of trialkylamine (excluding trimethylamine) and 50 ppm by volume or more and 400 ppm by volume or less of dimethylamine.

22. A method for purifying a trialkylamine according to any one of claims 12 to 17, wherein the trialkylamine purified by the purification method is a composition containing 99.9% by weight or more of trialkylamine (excluding trimethylamine) and 10 ppm by volume or less of dimethylamine.

23. synthesizing a crude trialkylamine (excluding crude trimethylamine); and purifying the crude trialkylamine using the purification method according to any one of claims 1 to 22.

Images