JP5750367B2 - Method for producing tertiary amine - Google Patents

Description

  The present invention relates to a method for producing a tertiary amine, and more particularly to a method for producing a tertiary amine in which a hydrogen-containing gas produced as a by-product is reused to suppress the amount of hydrogen used.

Tertiary amines are important intermediate materials in the household and industrial fields, and are used in various applications such as fiber softeners, shampoos, rinses, antistatic agents, cleaning agents, dispersants, and fiber auxiliaries. .
Various methods for producing tertiary amines are known, and one of them is a method in which an amine is brought into contact with an alcohol in the presence of hydrogen and a catalyst. As catalysts in this method, transition metal catalysts such as copper catalysts (see Patent Document 1) and nickel catalysts (see Patent Document 2), and noble metal catalysts such as ruthenium catalysts (see Patent Document 3) are known. Yes.

In the method using the catalyst, a tertiary amine is produced by the following three steps (a) to (c).
(A) Step of producing aldehyde by dehydrogenation reaction of raw material alcohol (b) Step of producing amine by nucleophilic addition of amine to aldehyde produced and subsequent dehydration reaction (c) By hydrogenation reaction of produced enamine In this production method, as a substrate for hydrogenation reaction, as a carrier gas for expelling water generated during the reaction from the reaction system, and further, reactivity, selectivity improvement, product It is necessary to use a large amount of hydrogen gas for the purpose of improving the appearance and colorability when derivatizing.

JP-A-2-233 Japanese Patent Laid-Open No. 50-30804 JP-A-8-243392

In the method for producing a tertiary amine through the steps (a) to (c), a large amount of hydrogen gas is required, and at the same time, a large amount of hydrogen-containing gas is discharged. Although reuse is desired, the hydrogen gas discharged so far has not been reused. Therefore, when an attempt was made to use hydrogen contained in the hydrogen-containing gas again for the reaction, it was found that the yield of the intended tertiary amine was lowered.
This invention makes it a subject to provide the manufacturing method of the tertiary amine which can suppress the usage-amount of the hydrogen gas used for reaction by aiming at reuse of hydrogen containing gas.

The inventors of the present invention have analyzed the hydrogen-containing gas discharged by the production method, and that the aldehyde-derived carbon monoxide generated in the step (a) is present in the hydrogen-containing gas. And since this carbon monoxide becomes a catalyst poison, it has been found that the hydrogen-containing gas can be reused by removing it.
That is, this invention provides the manufacturing method of the tertiary amine including the following process (1) and (2).
Step (1): An alcohol having 1 to 36 carbon atoms and a raw material amine represented by the following general formula (I) are introduced into the first reaction tank and reacted in the presence of a catalyst and hydrogen to produce reaction water and hydrogen. The process of continuing the reaction while discharging the contained gas out of the reaction system.
R ¹ R ² NH (I)
(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 36 carbon atoms. R ¹ and R ² are And may be bonded to each other to form a saturated hydrocarbon or unsaturated hydrocarbon ring.)
Step (2): After introducing the hydrogen-containing gas discharged from the first reaction tank into the second reaction tank and reducing the amount of carbon monoxide contained in the hydrogen-containing gas, part or all of the hydrogen-containing gas Step of introducing the first reaction vessel into the first reaction vessel.

  By reusing the hydrogen-containing gas, it is possible to provide a method for producing a tertiary amine capable of suppressing the amount of hydrogen gas used for the reaction.

In the method for producing a tertiary amine of the present invention, a specific alcohol and a raw material amine represented by the above general formula (I) are introduced into a first reaction vessel, and reacted in the presence of a catalyst and hydrogen to produce reaction product water. And the step (1) of continuing the reaction while discharging the hydrogen-containing gas out of the reaction system (hereinafter also referred to as “amination step”), and the hydrogen-containing gas discharged from the first reaction tank into the second reaction tank After introducing and reducing the amount of carbon monoxide contained in the hydrogen-containing gas, a step (2) of introducing part or all of the hydrogen-containing gas into the first reaction tank (hereinafter referred to as “carbon monoxide reduction step”) Also).
Hereinafter, each component used for this invention, each process, the manufacturing apparatus for implementing, etc. are demonstrated.

[Step (1): Amination step]
Step (1) of the present invention: In the amination step, the reaction proceeds as shown in the following reaction formula (II) to produce the target tertiary amine.
R ¹ R ² NH + R ³ OH → R ¹ R ² NR ³ (II)
In formula (II), R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 36 carbon atoms. R ¹ and R ² may be bonded to each other to form a saturated hydrocarbon or unsaturated hydrocarbon ring. R ³ represents a saturated or unsaturated hydrocarbon group having 1 to 36 carbon atoms.

In this amination step, an alcohol (R ³ OH) is dehydrogenated in the presence of a metal catalyst to form an aldehyde, and then the aldehyde is brought into contact with the raw material amine to form an enamine, A tertiary amine is formed by adding hydrogen to the enamine in the presence of a metal catalyst.
In this reaction, alcohol is dehydrogenated, and the resulting aldehyde is decarbonylated as a side reaction, thereby producing carbon monoxide. Since carbon monoxide becomes a catalyst poison of the metal catalyst, carbon monoxide in the waste hydrogen is reduced by the following step (2): carbon monoxide reduction step.
The alcohol and raw material amine that can be used in the amination step are as follows.

<Alcohol>
The alcohol R ³ OH used in the present invention is an alcohol having a saturated or unsaturated hydrocarbon group having 1 to 36 carbon atoms.
The alcohol having 1 to 36 carbon atoms is preferably a linear or branched chain having 2 to 30 carbon atoms, more preferably 6 to 24 carbon atoms, still more preferably 10 to 22 carbon atoms, and particularly preferably 12 to 16 carbon atoms. Or the alcohol which has a cyclic | annular saturated or unsaturated hydrocarbon group is mentioned. The hydrocarbon group may contain one or more functional groups such as a hydroxyl group, an amino group, an alkylamino group, and an alkoxy group.
Preferred examples of the alcohol include a monohydric alcohol having a saturated hydrocarbon group having 1 to 30 carbon atoms, a dihydric alcohol having a saturated hydrocarbon group having 2 to 30 carbon atoms, a saturated cyclic alcohol having 6 to 22 carbon atoms, and carbon. Examples thereof include unsaturated cyclic alcohols of Formula 6-22.

Examples of the monohydric alcohol having a saturated hydrocarbon group having 1 to 30 carbon atoms include methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, various butyl alcohols, various pentyl alcohols, various hexyl alcohols, various heptyl alcohols, various types Octyl alcohol, various nonyl alcohols, various decyl alcohols, various undecyl alcohols, various dodecyl alcohols, various tridecyl alcohols, various tetradecyl alcohols, 2-ethylhexyl alcohol, 3,5,5-trimethylhexyl alcohol, 3,7-dimethyl Examples include octyl alcohol and 2-propylheptyl alcohol. Here, “various” means various isomers including n-, tert-, and iso-.
Examples of the alcohol having an unsaturated hydrocarbon group having 2 to 30 carbon atoms include oleyl alcohol and geraniol.

  Examples of the dihydric alcohol having a saturated hydrocarbon group having 2 to 30 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, diglycol, 1,4-butanediol, and 1,5-pentane. Examples include diol, 1,6-hexanediol, and 2,2-bis [4-hydroxycyclohexyl] propane.

Examples of the saturated cyclic alcohol having 6 to 22 carbon atoms include cyclopentanol, cyclohexanol, cyclopentylmethanol, cyclohexylmethanol and the like.
Examples of the unsaturated cyclic alcohol having 6 to 22 carbon atoms include cyclopentenyl methanol, cyclohexenyl methanol, and cyclohexenyl alcohol.
Examples of other alcohols include behenyl alcohol, icosyl alcohol, methoxyethanol, propoxyethanol, butoxyethanol, polyisobutyl alcohol, polypropyl alcohol, and Ziegler alcohol obtained by the Ziegler method.
In these, a C2-C30 linear or branched alcohol is preferable, and a C2-C30 linear alcohol is more preferable.
The said alcohol can be used individually or in combination of 2 or more types.

<Raw material amine>
The raw material amine used in the present invention is an amine represented by the following general formula (I).
R ¹ R ² NH (I)
In the formula (I), R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 36 carbon atoms. R ¹ and R ² may be bonded to each other to form a saturated hydrocarbon or unsaturated hydrocarbon ring. Further, the ring may contain an unsaturated bond or a heteroatom (O, N, S, etc.). R ¹ and the carbon number of R ² is a hydrocarbon group is preferably from 1 to 20, more preferably 1 to 10, more preferably 1 to 6, 1 to 3 is particularly preferable.
Preferable examples of the raw material amine include aliphatic amines having 1 to 20 carbon atoms and aromatic amines having 6 to 20 carbon atoms. The raw material amine may be ammonia.

Examples of the aliphatic amine having 1 to 20 carbon atoms include monoalkylamines such as methylamine, ethylamine, n-propylamine, isopropylamine, various butylamines, various pentylamines and various hexylamines; dimethylamine, diethylamine, di-n- Examples include dialkylamines such as propylamine, diisopropylamine, various dibutylamines, various dipentylamines, and various dihexylamines. Dialkylamine is a carbon of each alkyl chain such as methylethylamine, methylpropylamine, methylbutylamine, methylpentylamine, methylhexylamine, methylheptylamine, methyloctylamine, methyldodecylamine, methylstearylamine, ethylpropylamine, etc. The number may be different.
Examples of aromatic amines having 6 to 20 carbon atoms include monoarylamines such as phenylamine, benzylamine, methylphenylamine, ethylphenylamine, methylbenzylamine, and ethylbenzylamine; diarylamines such as diphenylamine and dibenzylamine; The related compound is mentioned.
Examples of other amines include cyclic amines such as morpholine, pyrrolidine, piperazine, and isoindoline and related compounds.

  The raw material amine may be introduced continuously or intermittently into the first reaction tank. Moreover, when using a liquid amine, you may introduce | transduce the whole quantity of the amine used for reaction by one operation.

<Catalyst used in the amination step>
As a catalyst (amination catalyst) used in the amination step, for example, a transition metal catalyst such as a copper catalyst or a nickel catalyst, or a noble metal catalyst such as a ruthenium catalyst can be used.
As the copper-based catalyst, for example, JP-A-2-233 (one or more transition metals selected from Cu—Cr, Mu, Fe, Ni, Co, and Zn—an alkali metal such as a platinum group element—Li, Mg, etc.) , Alkaline earth metal catalysts), JP-A-2-234 (fourth period transition metal element such as Cu-Ni, Co, etc.-fourth component such as platinum group element-Al), and JP-A-2001-151733. (Cu-fourth period transition metal-platinum group element catalyst) and the like.
Examples of the nickel-based catalyst include Japanese Patent Laid-Open No. 50-30804 (Ni-Cu-Cr catalyst), Japanese Patent Laid-Open No. 7-69999 (Ni catalyst), and Japanese Translation of PCT International Publication No. 2005-527516 (Ni-Cu-Co). -ZrO ₂ catalyst) and catalysts described in JP 2007-176889 A (Ni-Cu-alkali metal catalyst).
Examples of the ruthenium catalyst include, for example, JP-A-8-243392 (Ru-porous oxide catalyst), European Patent No. 729785 (Ru-noble metal catalyst), JP-A-2008-150312 (Ru-ZrO). ₂ composite oxide and / or metal surface-treated ZrO ₂ catalyst), Japanese Patent Application Laid-Open No. 2007-176891 (Ru-porous oxide catalyst), Japanese Patent Application Laid-Open No. 2007-176892 (Ru-Ni, Co) The above metal component-a catalyst containing one or more metal components of La, Y, Mg, Ba), and U.S. Pat. No. 4,912,260 (one or more of Ru-Ni-Pd, Re, Ir) Examples of the catalyst include a catalyst containing a metal component).

From the viewpoint of reactivity, the amination catalyst is selected from the following (i) fourth period transition metal, (ii) platinum and fifth transition metal, and (iii) alkali metal and alkaline earth metal in addition to copper. A catalyst containing at least one selected from the above as the main active component and satisfying the following conditions (a) to (c) is preferable. The ratio of the conditions (a) to (c) is a metal molar ratio.
(I) Fourth period transition metal: at least one selected from nickel, cobalt, iron, chromium, and zinc.
(Ii) Platinum and the fifth period transition metal: at least one selected from platinum, palladium, ruthenium, and rhodium.
(Iii) Alkali metal and alkaline earth metal: at least one selected from lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, and barium.

Condition (a): Copper / fourth period transition metal = 1/9 to 99/1, preferably 50/50 to 99/1
Condition (b): platinum and fifth transition metal / (copper + fourth transition metal) = 0 to 0.1, preferably 0 to 0.05
Condition (c): 4th period transition metal / (alkali metal + alkaline earth metal) = 1/0 to 1/2, preferably 1/0 to 1/1
Among the amination catalysts, a catalyst containing copper and a fourth periodic transition metal (particularly nickel), a catalyst containing copper and platinum or a fifth periodic transition metal (particularly ruthenium), a copper and a fourth periodic transition metal ( In particular, a catalyst containing nickel) and a fifth period transition metal (particularly ruthenium) is preferable.
The amination catalyst can be used by supporting the main active component on a porous carrier such as a metal oxide or a composite oxide. There is no restriction | limiting in particular in the shape, Any of powder shape, spherical shape, and columnar shape (pellet shape) may be sufficient.
The amination catalyst can be used alone or in combination of two or more.

The amination catalyst may be unreduced or reduced, but is preferably reduced from the viewpoint of reactivity and selectivity. The reduced amination catalyst can be prepared by performing reduction in a reducing atmosphere such as hydrogen gas. Therefore, for example, after the amination catalyst in an unreduced state is placed in a reaction vessel together with the raw material alcohol, it can be prepared in a step of raising the temperature to the reaction temperature while introducing hydrogen gas.
The amount of the amination catalyst used is preferably adjusted as appropriate according to the reaction method. When the reaction system is a suspension bed batch type, from the viewpoint of reactivity and selectivity, the amount of the amination catalyst used is preferably 0.01 to 30% by weight with respect to the raw material alcohol, 0.1 to 10 Weight percent is more preferred.

<Reaction conditions for the amination step>
There is no restriction | limiting in particular in the reaction system of an amination process, A suspension bed batch type or a fixed bed flow type may be sufficient. 100-300 degreeC is preferable from a reactive viewpoint, and, as for reaction temperature, 150-250 degreeC is more preferable. The reaction pressure is preferably 100 kPa to 40 MPa, more preferably 100 kPa to 25 MPa.

When introducing hydrogen into the first reaction tank, it is preferable to introduce a mixed gas in which hydrogen and a gas other than hydrogen are mixed into the reaction system from the viewpoint of reactivity and selectivity. Here, the gas mixed with hydrogen is not particularly limited as long as it does not adversely affect hydrogen and the amination reaction. By using the mixed gas, water generated by the reaction can be efficiently removed out of the reaction system.
The introduction rate of the hydrogen-containing gas is preferably 3 to 300 NL / h, more preferably 8 to 100 NL / h, and still more preferably 20 to 50 NL / h per 1 kg of the raw material alcohol. Here, NL represents the volume (normal liters) in the standard state, that is, 0 ° C. and 101.3 kPa.
The water produced by the reaction may be removed intermittently or continuously, but it is preferably removed continuously from the viewpoint of reactivity and selectivity. The water produced by the reaction may be removed by adding an appropriate solvent to the reaction system and azeotropically.
The hydrogen-containing gas discharged from the first reaction tank may be introduced into the second reaction tank after being stored in a tank or the like, or may be introduced into the second reaction tank as it is without being stored.
When gaseous amine is used as a raw material, the residual amine gas in the hydrogen gas should be removed in advance before introducing it into the second reaction tank from the viewpoint of ensuring the reactivity in the second reaction tank and suppressing side reactions. Is preferred. An acid scrubber or the like can be used as a method for removing the residual amine gas (step (A) described later).
Here, the gaseous state has a vapor pressure of 1 kPa or more at room temperature (25 ° C.).

[Step (2): Carbon monoxide reduction step]
In the amination step, a part of the generated aldehyde is converted into carbon monoxide by a side reaction (decarbonylation reaction). This carbon monoxide coats the active site of the amination catalyst used in the amination step or forms a complex with the amination catalyst to deactivate the catalyst. Therefore, in the present invention, in order to reuse the hydrogen-containing gas, it is necessary to reduce the amount (concentration) of carbon monoxide in the second reaction tank.
Methods for reducing carbon monoxide include (i) a method of adsorption using an adsorbent material such as activated carbon, (ii) a biochemical method of adsorbing to hemoglobin, etc., and (iii) further oxidizing carbon monoxide to produce carbon dioxide. Examples thereof include a chemical method for converting to carbon, and (iv) a methanation method for converting carbon monoxide to methane.
Among these, from an industrial viewpoint, a methanation method (methanation method) in which (iv) carbon monoxide is converted into methane using a catalyst is preferable.

<Catalyst used in the carbon monoxide reduction step>
Examples of the catalyst that can be used in the methanation method include nickel, cobalt, ruthenium, platinum, rhodium, palladium, molybdenum, tungsten, and rhenium. In the present invention, it is preferable to use nickel, cobalt, and ruthenium, which are particularly highly active.
In addition, you may use 1 or more types of the said metal as a main active component, and the metal different from this main active component may be used as a co-active component.
Further, from the viewpoint of improving the catalytic activity, the main active component is applied to a porous support of metal oxide or composite oxide such as Al ₂ O ₃ , SiO ₂ , TiO ₂ , CeO ₂ , MgO, and La ₂ O _3. May be supported. Furthermore, commercially available Ru / γ-Al ₂ O ₃ , Ni / diatomaceous earth, or the like may be used from the viewpoint of catalyst activity and availability.
There is no restriction | limiting in particular in the shape of a methanation catalyst, Any of powder form, spherical shape, and columnar shape (pellet shape) may be sufficient.

<Reaction conditions for the carbon monoxide reduction process>
The reaction temperature in the carbon monoxide reduction step is preferably changed according to the catalyst used from the viewpoint of reactivity.
The reaction temperature when using at least one selected from ruthenium, platinum, rhodium, palladium, tungsten and rhenium as the main active component of the catalyst is preferably 100 to 350 ° C, more preferably 120 to 300 ° C.
Moreover, as reaction temperature in the case of using at least 1 sort (s) chosen from nickel, cobalt, and molybdenum as a main active component of the said catalyst, 150-600 degreeC is preferable and 200-550 degreeC is more preferable.
The reaction pressure is preferably 100 kPa to 40 MPa, more preferably 100 kPa to 25 MPa, even when any metal is used as the main active component.

The concentration of carbon monoxide discharged from the second reaction tank depends on the raw material of the amination reaction in the first reaction tank, the catalyst, the reaction conditions such as temperature and pressure, the degree of quality required for the target product, and the reuse application. Although it varies depending on, etc., it is usually 5000 ppm or less, preferably 1000 ppm or less, more preferably 300 ppm or less, more preferably 100 ppm or less, and still more preferably 20 ppm or less.
The hydrogen-containing gas discharged from the second reaction tank may be stored in a tank or the like and then introduced into the first reaction tank to perform an amination reaction, or may be introduced into the first reaction tank without being stored, It may be used continuously. In the present invention, hydrogen may be reused by introducing a part of the hydrogen-containing gas discharged from the second reaction tank into a tank other than the first reaction tank and the second reaction tank.
When hydrogen-containing gas is circulated between the first reaction tank and the second reaction tank, a gas holder having an appropriate volume is installed in the flow path between the first reaction tank and the second reaction tank. It is preferable to manage the pressure in the path.

[Step (A)]
In the present invention, it is preferable to provide a step (A) for reducing the amount of amine contained in the discharged hydrogen-containing gas between the step (1) and the step (2). Specifically, it is preferable to provide a removing means for removing residual amine gas between the first reaction tank and the second reaction tank so that gaseous amine is not mixed into the second reaction tank.
In the present invention, it is preferable that the hydrogen-containing gas discharged in step (1) is brought into contact with water to reduce the amount of raw material amine contained in the hydrogen-containing gas. It is more preferable to reduce the amount of the raw material amine contained in the hydrogen-containing gas by contacting with the hydrogen-containing gas.
As a method for bringing the hydrogen-containing gas into contact with water or an acid aqueous solution, water or an acid aqueous solution may be bubbled with a hydrogen-containing gas to absorb amine in the water or acid aqueous solution, or water in a showering state or The amine may be absorbed by bringing the hydrogen-containing gas into countercurrent contact with the acid aqueous solution.
Specific examples of the removing means include an absorption tower using water as a solvent, and an acid scrubber using a sulfuric acid aqueous solution as a medium. It is preferable that the hydrogen-containing gas is first absorbed in an absorption medium such as water to recover most of the amine, and then the remaining amine is removed with an acid scrubber.
In addition, you may provide the alkali scrubber for neutralizing the liquid which disperses with a hydrogen-containing gas flow after passing through an acid scrubber.
The residual amine concentration in the hydrogen-containing gas after the step (A) is preferably 1% by weight or less, more preferably 0.2% by weight or less, and further preferably 0.05% by weight or less.

[manufacturing device]
A production apparatus for carrying out the present invention is not particularly limited as long as it can carry out the amination step and the carbon monoxide reduction step. For example, a first reaction tank that performs an amination reaction, a second reaction tank for removing carbon monoxide contained in a hydrogen-containing gas discharged from the first reaction tank, a first reaction tank, and a second reaction tank An apparatus having a pipe directly or indirectly connected to the reaction vessel can be used.
The first reaction tank is preferably equipped with a pipe for introducing hydrogen and raw material amine, and further equipped with a condenser and a separator for condensing and separating reaction product water, hydrogen gas, alcohol and the like. Is preferred.
The second reaction tank is preferably one that can perform the above methanation, but may be an apparatus that can remove or convert carbon monoxide.
It is preferable to provide the above-mentioned removing means for removing excess amine that has not been consumed in the amination reaction between the first reaction tank and the second reaction tank.

An outline of an embodiment of the present invention will be described by taking a batch reaction as an example.
First, the amination reaction tank, which is the first reaction tank, is charged with raw material alcohol and catalyst, hydrogen is introduced, and the temperature rise is started with sufficient stirring. The catalyst is reduced and activated during the temperature rise. After reaching a predetermined temperature, the raw material amine is introduced to start the reaction. The introduction method may be continuous or intermittent, and when a liquid amine is used, it may be introduced all at once. The water produced during the reaction is discharged out of the reaction system together with waste hydrogen gas (hydrogen and unreacted gaseous amine if gaseous amine is used) and a small amount of oil such as alcohol and hydrocarbons. After passing through the separator, it is separated from the oil. The separated oil is returned to the first reaction tank.
The hydrogen-containing gas discharged from the first reaction tank is introduced into the second reaction tank. When gaseous amine is used as the raw material amine, unreacted gaseous amine is contained in the hydrogen-containing gas, so after removing the amine gas in the hydrogen-containing gas through the amine gas removing means, the hydrogen-containing gas is transferred to the second reaction tank. It is preferable to introduce. The hydrogen-containing gas discharged from the second reaction tank is returned to the amination reaction tank and reused.

The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Example 1
<Process (1): Amination process>
A 2 L separable flask was prepared as a first reaction tank, and a condenser and a separator for condensing and separating reaction product water and the like were attached thereto. A total of 1200 g of mixed alcohol (raw alcohol) of lauryl alcohol (carbon number 12) / myristyl alcohol (carbon number 14) = 70/30 (mass ratio) was added to this separable flask.
In a 1 L flask, copper nitrate, nickel nitrate, and ruthenium chloride dissolved in water so that the molar ratio of each metal atom is Cu: Ni: Ru = 4: 1: 0.01 is added, and the mixture is stirred and stirred. Warm up. After charging the zeolite at 50 ° C., a 10% by weight aqueous sodium carbonate solution was gradually added dropwise at 90 ° C., and after aging for 1 hour, the precipitate was filtered, washed with water, dried, and calcined at 600 ° C. for 3 hours to obtain Cu— A Ni-Ru / zeolite catalyst (the molar ratio of each metal atom was Cu: Ni: Ru = 4: 1: 0.01) was prepared. This catalyst was added in an amount of 0.14% by weight based on the raw material alcohol.
While stirring the solution at a speed of 950 r / min, hydrogen was introduced into the flask at a flow rate of 35 NL / hr using a circulation pump, and a series of reaction processes consisting of a first reaction tank and a second reaction tank described later. The inside was circulated. The temperature of the first reaction tank was raised to a temperature at which the catalyst could be reduced, and the catalyst was reduced by holding for a certain period of time.
After the reduction of the catalyst was completed, dimethylamine and hydrogen gas were mixed and introduced into the reaction system. The temperature of the reaction system was gradually raised and the amination reaction was carried out while maintaining the temperature at 225 ° C. The reaction was followed appropriately by gas chromatography.
The hydrogen-containing gas discharged from the first reaction tank is converted into an amine gas removing means (the introduced hydrogen-containing gas is passed through a flask containing water by bubbling, and further, a sulfuric acid aqueous solution trap and a sodium hydroxide aqueous solution trap are used. The raw material amine component contained in the hydrogen-containing gas was removed by passing through an amine gas removing means). The amine gas concentration in the hydrogen-containing gas 30 minutes after the start of the reaction was determined by gas chromatography (trade name: “GC-3200”, manufactured by GL Sciences Inc., column: Varian capillary column CP-SiL 8CB For Amines inner diameter 0.32 mm × The length was 50 m, the film thickness was 5.0 μm, the oven temperature was 60 ° C., the injection temperature was 110 ° C., the detector temperature was 110 ° C., and the detector was TCD). The hydrogen-containing gas after removal of the amine component was introduced into the second reaction tank through a 12 L waste gas holder made of SUS.
The waste gas holder was replaced with pure hydrogen gas before the start of the reaction, and operated at a pressure of 103 to 160 kPa depending on the progress of the amination reaction.

<Process (2): Carbon monoxide reduction process>
A 0.5 wt% Ru / Al ₂ O ₃ catalyst (manufactured by Johnson Matthey, trade name: “Pellets, Type 146”) was used as the catalyst in the second reaction tank, and the catalyst was put into a SUS reactor having an inner diameter of 1.1 cm. Filled with 9.0 g. The temperature of the 2nd reaction tank was 220 degreeC, and the pressure of the 2nd reaction tank was set to the same pressure as a 1st reaction tank. The hydrogen-containing gas discharged from the second reaction tank was introduced into the first reaction tank and circulated to continue the reaction.
The time spent for the remaining amount of unreacted alcohol in the first reaction tank to be reduced to 1% by weight of the amount of alcohol at the start of the reaction is defined as the reaction time, the amount of hydrogen used, the composition of the product, and the first The concentration of carbon monoxide contained in the hydrogen-containing gas when introduced into the reaction vessel was measured. The results are shown in Table 1.
The carbon monoxide concentration was determined by gas chromatography (manufactured by Shimadzu Corporation, trade name: “GC-14A”) equipped with a methanizer (manufactured by Shimadzu Corporation, trade name: “MTN-1, Shimalite-Ni”). , Column: molecular sieve 5A; inner diameter 3.2 mm × length 4 m, oven temperature 80 ° C., injection temperature 80 ° C., detector temperature 80 ° C., carrier He gas 60 mL / min), the reaction was completed after 30 minutes had elapsed. Until, it is the average value of the values measured at intervals of 30 minutes. In Example 1, it was less than the detection limit (1 ppm) in all measurements.

Example 2
The reaction was performed in the same manner as in Example 1 except that the temperature of the second reaction tank was 180 ° C. and the average concentration of carbon monoxide discharged from the second reaction tank was maintained at 3700 ppm. The results are shown in Table 1.
Comparative Example 1
The reaction was performed in the same manner as in Example 1 except that the hydrogen-containing gas discharged from the first reaction tank was discarded without being circulated and the reaction was performed while always introducing pure hydrogen gas. The results are shown in Table 1.
Comparative Example 2
The reaction was carried out in the same manner as in Example 1 except that the hydrogen-containing gas discharged from the first reaction tank was introduced into the first reaction tank without passing through the second reaction tank. The results are shown in Table 1.

From Table 1, according to the methods of Examples 1 and 2, carbon monoxide produced as a by-product is reduced, so that the hydrogen-containing gas produced as a by-product can be reused. As a result, the hydrogen gas used in the reaction The amount used can be greatly reduced.
On the other hand, when the reaction is carried out by introducing the hydrogen-containing gas into the first reaction tank without passing through the second reaction tank (Comparative Example 2), the carbon monoxide concentration is increased, and the activity of the amination catalyst is decreased. Reduce yield.

Example 3
The reaction was conducted in the same manner as in Example 1 except that the raw material alcohol was changed to 1200 g of stearyl alcohol (trade name: “CALCOL 8098” manufactured by Kao Corporation). The results are shown in Table 2.

  The amount of hydrogen used in the reaction in Example 3 was 27.2 L. Assuming that this reaction was performed without recovering hydrogen, the amount of hydrogen gas circulated was estimated to be 151 L.

Example 4
Example 1 except that the raw material alcohol was changed to decyl alcohol and the raw material amine was changed to monomethylamine, the reaction temperature was 195 ° C., the catalyst concentration was 1.2 wt% with respect to the raw material alcohol, and the hydrogen flow rate was 18 NL / h. The reaction was performed in the same manner. The results are shown in Table 3.

The amount of hydrogen used in the reaction in Example 4 was 24.1 L. Assuming that this reaction was performed without recovering hydrogen, the amount of hydrogen gas circulated was estimated to be 74 L.
Further, Examples 3 and 4 show that various tertiary amines can be obtained with high yield and high selectivity by the production method of the present invention.

Example 5
The reaction was carried out in the same manner as in Example 1 except that the hydrogen-containing gas discharged from the first reaction tank was directly introduced into the second reaction tank without passing through the amine gas removing means. The amount of the amine component before introduction of the second reaction tank was 1.0% by weight.
The results of Example 5 are shown in Table 4 together with the results of Example 1 and Comparative Example 2. From these results, it is understood that the reactivity and the selectivity of dimethylalkylamine are further improved by providing the step (A).

  According to the method for producing a tertiary amine of the present invention, since the amount of hydrogen used can be suppressed, it is possible to provide an extremely ecological and clean industrial process capable of reducing the burden on the environment.

Claims (9)

A method for producing a tertiary amine, comprising the following steps (1) and (2).
Step (1): An alcohol having 1 to 36 carbon atoms and a raw material amine represented by the following general formula (I) are introduced into the first reaction tank and reacted in the presence of a catalyst and hydrogen to produce reaction water and hydrogen. The process of continuing the reaction while discharging the contained gas out of the reaction system.
R ¹ R ² NH (I)
(In the formula, R ¹ and R ² each independently represent a hydrogen atom or a linear, branched or cyclic saturated or unsaturated hydrocarbon group having 1 to 36 carbon atoms. R ¹ and R ² are And may be bonded to each other to form a saturated hydrocarbon or unsaturated hydrocarbon ring.)
Step (2): The hydrogen-containing gas discharged from the first reaction tank is introduced into the second reaction tank, and the amount of carbon monoxide contained in the hydrogen-containing gas is reduced by bringing the hydrogen-containing gas into contact with a metal catalyst. A step of introducing a part or all of the hydrogen-containing gas into the first reaction tank after the reduction. A step (1) and step (2) the following steps between (A), 3 grade method for producing amines according to claim 1.
Step (A): A step of reducing the amount of raw material amine contained in the discharged hydrogen-containing gas. The method for producing a tertiary amine according to claim 2 , wherein in step (A), the hydrogen-containing gas is brought into contact with water to reduce the amount of the raw material amine contained in the hydrogen-containing gas. The method for producing a tertiary amine according to claim 2 or 3 , wherein, in the step (A), the hydrogen-containing gas is brought into contact with an acid aqueous solution to reduce the amount of the raw material amine contained in the hydrogen-containing gas. Metal catalyst in the second reaction vessel, in which nickel, cobalt, ruthenium, platinum, rhodium, palladium, molybdenum, at least one selected from the group consisting of tungsten and rhenium and a main active ingredient, according to claim 1 5. A method for producing a tertiary amine according to any one of 4 above. The main active component of the metal catalyst in the second reaction tank is at least one selected from the group consisting of ruthenium, platinum, rhodium, palladium, tungsten and rhenium, and the reaction temperature of the second reaction tank is 100 to 350 ° C. The method for producing a tertiary amine according to claim 5 . As main active ingredient of a metal catalyst in the second reaction vessel, nickel, with at least one selected from the group consisting of cobalt and molybdenum, the reaction temperature of the second reaction vessel to 150 to 600 ° C., to claim 5 The manufacturing method of tertiary amine of description. The method for producing a tertiary amine according to any one of claims 1 to 7 , wherein the reaction is performed at a pressure of the second reaction tank of 100 kPa to 40 MPa. The method for producing a tertiary amine according to any one of claims 1 to 8 , wherein the reaction is performed at a temperature of the first reaction tank of 100 to 300 ° C and a pressure of 100 kPa to 40 MPa.