JPH09100258A - Production of ethylamine compounds - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an ethylamine compound from ethyl alcohol (EtOH) in simplified processes. SOLUTION: This method for producing the ethylamine compound by reacting EtOH with ammonia in the presence of a catalyst in the atmosphere of hydrogen and subsequently separating the respective amines from the crude reaction product mixture containing the ethylamine compound. The characteristics comprise using (A) the 70-96wt.% pure EtOH containing low boiling point distillation fractions as a raw material, feeding (A) the EtOH and (B) a low concentration EtOH aqueous solution obtained from a process for separating the produced ethylamine compound into an EtOH distillation tower so that a position for feeding (A) the EtOH is higher than a position for feeding (B) the low concentration EtOH aqueous solution, distilling the mixture in the distillation tower, discharging (C) the EtOH vapor higher in the purity than that of (A) the EtOH from an intermediate distillation stage between both the feeding positions, and subsequently supplying the discharged material into the reaction process.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing ethylamines. More specifically, the present invention relates to a method for producing ethylamines using ethyl alcohol by a simplified process.

[0002]

2. Description of the Related Art As a method for producing ethylamines such as monoethylamine, diethylamine and triethylamine, a method of reacting acetaldehyde, ammonia and hydrogen using a catalyst (acetaldehyde method) is known. A method using ethyl alcohol instead of the acetaldehyde (ethyl alcohol method) is also known, and a useful catalyst has been proposed (JP-A-58-17).
No. 4348). In the latter case, unlike the former, hydrogen is not consumed in the reaction and is only necessary to keep the reaction system in a reducing atmosphere. In addition, the raw material ethyl alcohol is easier to handle than acetaldehyde, can be obtained at a low cost, and the heat of reaction is smaller than that of the former case.

In the ethyl alcohol method, Japanese Patent Laid-Open No.
As described in JP-A 2-144607, when ethylamines such as monoethylamine, diethylamine and triethylamine are produced by reacting ammonia with ethyl alcohol, the mixture of each amine is water or ethyl alcohol. And a crude reaction product mixture with ammonia.

As a method for treating the crude reaction product mixture, first, unreacted ammonia is separated and recovered and recycled to an ammonia supply source for reuse, and the remaining product amines from which ammonia is separated and recovered are distilled. Etc. to separate each amine. At that time, a low-concentration ethyl alcohol aqueous solution containing unreacted ethyl alcohol in the water produced by the reaction and the water supplied as necessary for the process is obtained.
If this is discarded as it is, it may cause pollution of wastewater and also a loss of ethyl alcohol. Then, this is distilled to recover ethyl alcohol, and the raw material ethyl alcohol is converted into ethyl alcohol vapor by a vaporizer with a vaporizer.
Feed to 220 ° C. reactor.

[0005]

According to the above-mentioned method for producing ethylamines by the ethyl alcohol method, ethyl alcohol is recovered by distilling a low-concentration ethyl alcohol aqueous solution, and must be vaporized by a vaporizer together with ethyl alcohol as a raw material. However, there was room for improvement in terms of energy. Further, the content of diethyl ether in the raw material ethyl alcohol must be, for example, 1 ppm or less so that it can be used for the reaction in order to simplify the purification step of the produced amine, and such raw material ethyl alcohol is expensive. Is. Therefore, if inexpensive ethyl alcohol containing a relatively large amount of impurities such as diethyl ether can be used as a raw material, it was expected that the production process would be more desirable in terms of cost.

[0006]

Means for Solving the Problems As a result of diligent study on such problems relating to the production of ethylamines by the ethyl alcohol method, the present inventors have found that unreacted ethyl alcohol is obtained from an aqueous solution of low-concentration ethyl alcohol obtained after separation of produced ethylamines. It was found that the above problems can be solved all at once by devising a distillation column for recovering the above so that the raw material ethyl alcohol can be distilled and purified at the same time, and the present invention has been completed.

That is, according to the present invention, in a hydrogen atmosphere, ethyl alcohol and ammonia are reacted with a catalyst to obtain a crude reaction product mixture containing monoethylamine, diethylamine and triethylamine, and then ethylamines which are separated into respective amines are produced. In the method, as raw material ethyl alcohol, ethyl alcohol (A) having a low boiling fraction and a purity of 70 to 96% by weight is used, and the concentration obtained from the step of separating the ethyl alcohol (A) and the produced ethylamines is 0.1 to 20. Both of the low concentration ethyl alcohol aqueous solution (B) of weight% are supplied to the ethyl alcohol distillation column so that the supply position of the ethyl alcohol (A) is higher than the supply position of the low concentration ethyl alcohol aqueous solution (B). And distilled more than ethyl alcohol (A) from the intermediate distillation stage at both supply positions. Taking out a high ethyl alcohol vapor (C), the method of producing ethylamine, which comprises supplying to the reaction step is provided. Hereinafter, the present invention will be described in detail.

As the catalyst that can be used in the present invention, a suitable amination catalyst such as nickel or copper is used. Alternatively, reduced cobalt dispersed on the porous carrier described in JP-A-56-166151, and JP-A-58-1
It is possible to use, but not limited to, those containing nickel atoms in a metal state described in Japanese Patent Publication No. 74348 and at least one of magnesium, manganese, calcium and barium atoms in a metal or oxide state. Not something.

The ethyl alcohol (A) usable in the present invention has a purity of 70 to 96% by weight or less, preferably 85 to 96% by weight, including a low boiling fraction. Even if the purity is higher than 96% by weight, there is no problem in the process, but the significance of the present invention that inexpensive ethyl alcohol is used as a raw material is lowered, while when the purity is lower than 70% by weight, the ethyl alcohol distillation column is used. It is not preferable because it increases the energy load.

As such ethyl alcohol (A), one produced by any known method can be used. For example, (1) ethyl alcohol obtained by the direct hydration method of ethylene, (2) ethyl alcohol obtained by the sulfuric acid method in which concentrated sulfuric acid absorbs and hydrolyzes ethylene, and (3) ethyl alcohol obtained by the fermentation method are used. be able to. Among these, ethyl alcohol produced by (1) or (2) containing a low boiling fraction such as diethyl ether and water as impurities is preferable. Particularly, it is preferable to use relatively inexpensive ethyl alcohol containing 0.5% by weight or more of diethyl ether.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A specific example of the implementation process of the present invention will be described below with reference to FIG. Note that FIG. 1 shows only the outline of main devices. In FIG. 1, 1 is a raw material ethyl alcohol supply line, 2 is an ethyl alcohol distillation column, 3 is an ethyl alcohol vapor supply line, 4 is a reaction process, 5 is a raw material ammonia supply line, 6 is a hydrogen supply line, and 7 is an ammonia separation process. , 8 is a recovered ammonia reflux line, 9 is an amine separation process, 10 is each amine separated, 11 is a low-concentration ethyl alcohol aqueous solution supply line, 12 is a can discharge water discharge line, 13 is a wastewater treatment process, 1
4 is an overhead condenser, and 15 is a low boiling impurity discharge line.

The ethyl alcohol supplied from the raw material ethyl alcohol supply line 1 is distilled in the ethyl alcohol distillation column 2 together with the low-concentration ethyl alcohol aqueous solution supplied from the low-concentration ethyl alcohol aqueous solution supply line 11. The distillation column may be a packed column or a plate column. Usually, the impurities contained in ethyl alcohol are mostly low boiling fractions such as diethyl ether, and the high boiling impurities are few. On the other hand, the low-concentration ethyl alcohol aqueous solution usually has an ethyl alcohol concentration of 0.1 to 20% by weight, preferably 1 to 15%.
Since most of the water is water, the feed positions of both of them in the ethyl alcohol distillation column are the upper stage of the former and the lower stage of the latter. Then, the ethyl alcohol vapor necessary for the reaction is obtained from between the both supply stages, and the reaction line 4 is supplied through the supply line 3.
Supplied to The impurity composition and concentration of the raw material ethyl alcohol (A), low concentration ethyl alcohol aqueous solution (B)
The capacity of the distillation column, the supply stage for both and the extraction stage for the ethyl alcohol vapor (C) may be appropriately adjusted depending on the concentration of the above. In this case, the purity of the ethyl alcohol vapor (C) is higher than that of the ethyl alcohol (A), but it is preferable that the content of diethyl ether in the vapor is 1 ppm or less and substantially not detected.

On the other hand, the bottom water of the distillation column 2 contains a trace amount of high boiling impurities and a trace amount of ethyl alcohol, and its discharge line 12
Is led to the wastewater treatment process 13. The fraction from the top of the distillation column is cooled by an overhead condenser, part of which is refluxed, and the rest is withdrawn from the low boiling impurity discharge line 15.

In the reaction step 4, the ethyl alcohol vapor and the ammonia vapor supplied from the raw material ammonia supply line 5 react in the presence of the catalyst to produce amines. At that time, hydrogen is supplied from the hydrogen supply line 6 in order to keep the reaction system in a reducing atmosphere. The reaction conditions vary depending on the type of catalyst and the feed rate of raw materials, but are usually set within a temperature range of 90 to 220 ° C. Also, the pressure is normal pressure ~
The pressure is set to 10 kg / cm ² (gauge), preferably normal pressure. The supply ratio of hydrogen / ammonia / ethyl alcohol is usually (1-10) / (0.2-5) / on a molar ratio basis.
1, preferably in the range of (4 to 7) / (0.5 to 3) / 1.

The crude reaction product mixture is ammonia separation step 7
The unreacted ammonia is separated and recovered by a means known in the art, and is refluxed to the reaction step 4 via the line 8.
The crude reaction product mixture from which unreacted ammonia has been separated is then introduced into the amine separation step 9 and separated into monoethylamine, diethylamine and triethylamine ethylamines 10 by a known method such as distillation. Then, since the low-concentration ethyl alcohol aqueous solution containing unreacted ethyl alcohol is discharged from the amine separation step 9, it is supplied from the supply line 11 to the ethyl alcohol distillation column 2 as described above, and is distilled together with the raw material ethyl alcohol. Reuse the reaction ethyl alcohol.

In contrast to FIG. 1 of the process using the present invention, FIG. 2 shows a process adopting a conventional method. In addition, in FIG. 2, equipment that performs the same function as in FIG.
The same numbers are used for lines and processes. The main difference between FIG. 2 and FIG. 1 is that high-purity ethyl alcohol having a diethyl ether content of 1 ppm or less (undetected) is usually used as a raw material, and the raw material high-purity ethyl alcohol supplied from the supply line 1 ′ is used. Alcohol is vaporizer 16
Is converted into steam and supplied to the reaction step 4.
The low-concentration ethyl alcohol aqueous solution supplied from the amine separation step 9 is distilled only in the ethyl alcohol distillation column 2, and the high-purity ethyl alcohol fraction distilled from the top of the column is cooled to obtain recovered ethyl alcohol. It is temporarily stored in the tank 17 and supplied to the vaporizer 16 together with the raw material high-purity ethyl alcohol.

As is clear from the comparison between FIG. 1 and FIG. 2, according to the method for producing ethylamines of the present invention, even if inexpensive ethyl alcohol is used as a raw material, a new distillation column for purification thereof is required. Rather than being able to purify together with the recovery of ethyl alcohol from a low-concentration ethyl alcohol aqueous solution in the originally required distillation column 2, the related equipment such as the ethyl alcohol vaporizer and the recovery ethyl alcohol tank that were required in the conventional method Became unnecessary.
As described above, by using the present invention, the cost can be reduced and the process can be simplified in terms of both raw materials and equipment.

[0018]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

(Example 1) As the ethyl alcohol distillation column 2 of FIG. 1, a distillation facility comprising a glass Oldershaw column having an inner diameter of 40 mm and a plate number of 60, a condenser for reflux at the top, a reflux condenser and a condenser for side-cut vapor. Was used to supply 460 g of raw material crude ethyl alcohol to the 7th plate from the top of the tower and 780 g of the low-concentration ethyl alcohol aqueous solution to the 45th plate from the top of the tower. The high-purity ethyl alcohol taken out of the vapor from the side of the distillation column was condensed with a condenser and taken out. The composition of the raw material crude ethyl alcohol was 92.7% by weight of ethyl alcohol, 5.6% by weight of water, 1.3% by weight of diethyl ether, and 0.4% by weight of high boiling point. It is 96.3% by weight of water and 3.7% by weight of ethyl alcohol. The distillation column was distilled under a normal pressure and a reflux ratio of 20. High-purity ethyl alcohol (480 g / hr) from the side of the distillation column, and bottom liquid (753.5 / hr) from the bottom of the column.
g was removed. The composition of high-purity ethyl alcohol was 94.6% by weight of ethyl alcohol, 5.4% by weight of water, and 1 ppm or less of diethyl ether.
It was 7% by weight and 0.1% by weight of ethyl alcohol.

[0020]

EFFECTS OF THE INVENTION According to the present invention, compared with the conventional process, it is possible to use ethyl alcohol which is less expensive and to produce simplified process ethylamines.

[Brief description of the drawings]

FIG. 1 is an example of a process that can be used in the method for producing ethylamines of the present invention.

FIG. 2 is an example of a process used in a conventional method for producing ethylamines.

[Explanation of symbols]

 1 Raw Material Ethyl Alcohol Supply Line 2 Ethyl Alcohol Distillation Tower 3 Ethyl Alcohol Vapor Supply Line 4 Reaction Process 5 Raw Material Ammonia Supply Line 6 Hydrogen Supply Line 7 Ammonia Separation Process 8 Recovered Ammonia Reflux Line 9 Amines Separation Process 10 Separated Amines 11 Low Concentration Ethyl Alcohol Aqueous Solution Supply Line 12 Can Outlet Discharge Line 13 Wastewater Treatment Process 14 Overhead Condenser 15 Low Boiling Impurity Discharge Line

Claims (4)

[Claims] 1. A method for producing ethylamines in which a crude reaction product mixture containing monoethylamine, diethylamine and triethylamine is obtained by reacting ethyl alcohol and ammonia with a catalyst under a hydrogen atmosphere, and then separating into each amine, Purity including low boiling fraction as raw material ethyl alcohol 70-
Using 96% by weight of ethyl alcohol (A), both of the ethyl alcohol (A) and the low-concentration aqueous solution of ethyl alcohol (B) having a concentration of 0.1 to 20% by weight obtained from the step of separating the produced ethylamines are treated with ethyl acetate (A). Alcohol (A)
Is fed to the ethyl alcohol distillation column so that the feeding position thereof is higher than the feeding position of the low-concentration ethyl alcohol aqueous solution (B), and the distilling is performed from the intermediate distillation stage of both feeding positions than the ethyl alcohol (A). A method for producing ethylamines, characterized in that highly pure ethyl alcohol vapor (C) is taken out and supplied to a reaction step. 2. Ethyl alcohol (A), which is obtained by a direct hydration method of ethylene and contains by-produced diethyl ether as a low boiling fraction, is used. Production method. 3. As the ethyl alcohol (A), ethyl alcohol containing a by-produced diethyl ether as a low boiling fraction, which is obtained by a sulfuric acid method in which concentrated sulfuric acid is absorbed and hydrolyzed, is used. Item 2. A method for producing ethylamines according to Item 1. 4. The method for producing ethylamines according to claim 1, wherein the content of diethyl ether in the ethyl alcohol vapor (C) is 1 ppm or less.