JPH078839B2 - Method for producing N, N, N ', N'-tetramethyl-1.6-hexanediamine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention comprises reacting a 1,6-hexanediamine (hereinafter abbreviated as HA) with a formylating agent and hydrogen in the presence of a noble metal catalyst to produce N, The present invention relates to a method for producing N, N ', N'-tetramethyl-1,6-hexanediamine (hereinafter abbreviated as TMHA).

TMHA is useful as a raw material for dispersants, emulsifiers and foaming accelerators.

[Conventional technology]

Conventionally, as a method for producing TMHA, a method in which HA is reacted with formalin, formic acid and a basic organic acid (Japanese Patent Laid-Open No. 56-166).
No. 152) is known.

On the other hand, in the production of an aliphatic primary amine containing a hydrogenation catalyst maintained in a liquid phase under hydrogen pressure and an aliphatic tertiary amine in which formaldehyde is gradually added to an aliphatic secondary amine, an additional reaction is added to the reaction. As a catalyst, about 0.5 is used for the aliphatic primary amine or the aliphatic secondary amine.
Method for producing aliphatic tertiary methylamine using 3 to 3% by weight of basic organic acid (JP-B-39-17905) and primary amine or secondary amine in the presence of palladium or platinum catalyst A long-chain aliphatic primary method such as a method for producing a tertiary amine (JP-A-60-130551) in which formaldehyde is reacted under a hydrogen pressure of 3 to 50 kg / cm ² (gauge pressure) at a temperature of 80 to 180 ° C. A method for producing a tertiary amine by reacting a secondary or secondary amine with a formylating agent and hydrogen in the presence of a hydrogenation catalyst is known.

[Problems to be solved by the invention]

However, in the conventional manufacturing method of TMHA, HA
The method of reacting formalin with formic acid and basic organic acid is, in addition to formic acid that acts as a reducing agent when dimethylating an amino group (about 4 mol of formic acid is necessary for 1 mol of HA), About 2 equivalents of basic organic acid which acts as a salt forming agent are required for 1 mol of HA. Furthermore, in order to obtain free TMHA from the reaction product, 1 mol of TMHA is used.
Therefore, a step of neutralizing the salt-forming agent with about 2 equivalents of alkali is required.

That is, a drawback of this method is that, in addition to using expensive formic acid as a reducing agent, a larger amount of basic organic acid and alkali are used. For this reason, wastewater containing a large amount of alkaline salts of basic organic acids is generated from the neutralization step, and there is a drawback that wastewater treatment costs are high.

On the other hand, conventional methods for producing long-chain aliphatic tertiary amines by reacting long-chain aliphatic primary amines or secondary amines with formalin and hydrogen in the presence of a hydrogenation catalyst are all special methods. It is a method in which a raw material long-chain aliphatic primary amine or secondary amine is charged into a reactor in an almost solvent-free state, a formalin is supplied, and reductive dimethylation is performed without using any solvent.

In this way, the long-chain aliphatic primary amine or secondary amine is reductively dimethylated in a nearly solvent-free state,
The method of producing TMHA requires high pressure hydrogen to achieve sufficient reaction performance. When such a method is carried out on an industrial scale, a pressure resistant reactor is required, which has a drawback that the equipment cost is high. Also, advanced technology is required in terms of operation management.

[Means for solving problems]

The present inventors have conducted extensive studies to solve the above-mentioned drawbacks of the prior art, and as a result, in the presence of a noble metal catalyst, formaldehyde and / or paraformaldehyde and hydrogen were used to reduce the reaction for reducing dimethylation of HA to carbon. Number 1-4
The high-quality TMHA can be produced in a high yield even when low-pressure hydrogen is used, by carrying out in the aliphatic alcohol solvent or in a mixed solvent of water and alcohol containing 30% by weight or more of the alcohol. They have found the present invention and reached the present invention.

That is, the present invention provides a formaldehyde and / or paraformaldehyde and HA in an aliphatic alcohol solvent having 1 to 4 carbon atoms or a mixed solvent of water and alcohol containing 30% by weight or more of the alcohol in the presence of a noble metal catalyst. A method for producing TMHA characterized by reacting with hydrogen.

Hereinafter, the present invention will be described in detail.

The main raw material HA used in the present invention can be produced by a known method such as an adipic acid method, an acrylonitrile electrolytic dimerization method, a butadiene method, and an ε-caprolactam method. The present invention can be smoothly carried out using HA produced by any of these methods. The HA used in the reaction may be used in the present invention in any form such as anhydrous form and aqueous solution form.

In the present invention, HA is supplied so that the initial concentration of HA in the reaction system is usually 5 to 50% by weight, preferably 10 to 40% by weight. The initial concentration of HA here means the amount of HA present in the liquid phase in% by weight relative to the total amount of HA, water and the aliphatic alcohol having 1 to 4 carbon atoms present in the liquid phase at the initial stage of the reaction. It is the value expressed by. When the initial concentration of HA is less than 5% by weight, productivity is low and it is not practical. On the other hand,
When the initial concentration of HA is 50% by weight or more, the reaction results tend to deteriorate, which is not preferable. In the present invention, as a system for supplying HA to the reaction system, either a batch system or a continuous system can be adopted.

The formaldehyde and / or paraformaldehyde used in the present invention acts as a formylating agent. In the present invention, formaldehyde and paraformaldehyde are usually used alone, but in some cases, a mixture of formaldehyde and paraformaldehyde may be used. Further, these formylating agents are usually
Commercially available products, for example in the form of a mixture with water and / or alcohol, can be used as such. In particular, according to the invention, the use of formaldehyde and / or paraformaldehyde in the form of a mixture with alcohol is preferred.

In the present invention, the amount of formaldehyde and / or paraformaldehyde used is usually 3.5 to 1 mol of HA.
It is 5.0 molar equivalents. Here, 1 molar equivalent of paraformaldehyde means 1 unit of formaldehyde constituting paraformaldehyde.

In the present invention, when the amount of formaldehyde and / or paraformaldehyde used is less than 3.5 molar equivalents per mole of HA, unreacted HA tends to remain in the reaction solution, which is especially advantageous when industrially carrying out the present invention. However, the recovery cost of unreacted HA increases, and it cannot be said to be an economical method for producing TMHA.

On the other hand, when the amount used exceeds 5.0 molar equivalents per mole of HA, the by-products of high boiling compounds increase and the quality of the product TMHA tends to deteriorate. The most preferable amount of formaldehyde and / or paraformaldehyde used is 3.9 to 1 mol of HA.
It is around 4.5 molar equivalents, that is, 4.0 molar equivalents.

In the present invention, the method of supplying formaldehyde and / or paraformaldehyde to the reaction system is arbitrary. The formaldehyde supply system is suitable for either the intermittent system or the continuous system because the formaldehyde form is usually liquid. On the other hand, the paraformaldehyde supply system is suitable for the batch system since the form of paraformaldehyde is usually powder.

In the present invention, the reductive dimethylation of HA has 1 to 4 carbon atoms.
It is important to carry out in the aliphatic alcohol solvent mentioned above or in a mixed solvent of water and the alcohol. Examples of the aliphatic alcohol having 1 to 4 carbon atoms used here include methanol, ethanol, n-propanol, iso-propanol, n-butanol, iso-butanol, sec-butanol, tert-butanol and the like. These alcohols can be used alone or as a mixture. It is preferable to use methanol which is industrially inexpensive.

Further, in the present invention, when the reductive dimethylation of HA is carried out in a mixed solvent of water and an aliphatic alcohol having 1 to 4 carbon atoms, the solvent is 30% by weight of the aliphatic alcohol having 1 to 4 carbon atoms.
It is important to include the above.

That is, in the present invention, the solvent has substantially 1 carbon atom.
It is necessary that the solvent is a single solvent consisting of an aliphatic alcohol of 4 to 4 or a mixed solvent with water containing 30% by weight or more of an aliphatic alcohol having 1 to 4 carbon atoms.

In the present invention, the mixed solvent of water and alcohol contains 30% by weight or more of an aliphatic alcohol having 1 to 4 carbon atoms,
Substantially present relative to the total amount of water and the aliphatic alcohol having 1 to 4 carbon atoms substantially present in the liquid phase in the reaction system (these are acting as a solvent in the reaction system) The amount of the aliphatic alcohol having 1 to 4 carbon atoms by weight
When expressed by, it means that it is 30% or more.

In the present invention, when the amount of the aliphatic alcohol having 1 to 4 carbon atoms in the mixed solvent with water is less than 30% by weight, the production rate of TMHA is significantly reduced, which is not preferable.

The noble metal catalyst used in the present invention may be one used as a usual hydrogenation catalyst, for example, palladium,
Platinum and ruthenium are mentioned. In the present invention,
Palladium-activated carbon catalyst and platinum-activated carbon catalyst supported on commercially available charcoal-based activated carbon or coconut husk activated carbon are preferably used. The amount of the noble metal supported on the noble metal catalyst is not particularly limited, but usually, a noble metal supported on the carrier in an amount of 0.1 to 10% by weight is used.

In the present invention, the noble metal catalyst is usually used by suspending it in the liquid phase of the reaction system. In order to promote the reductive dimethylation of HA smoothly, it is important to stir the liquid phase of the reaction system well and to disperse the noble metal catalyst as uniformly as possible. Regarding the amount of precious metal catalyst used with respect to HA, the reaction proceeds smoothly if it is used in excess, while TMHA is used if it is too small.
Will tend to decrease the production rate of. Usually, for example, 5% by weight
When using an activated carbon catalyst containing palladium, the raw material HA10
The amount of 5% by weight of palladium-activated carbon catalyst used relative to 0 parts by weight is in the range of about 1 to 50 parts by weight, preferably about 3 to
30 parts by weight. The catalyst in the reaction product liquid once used can be solid-liquid separated, and if necessary, washed with water, alcohol or a mixed solvent of water and alcohol, and then recycled.

In the present invention, the reaction is carried out under the pressure of hydrogen. That is, the reaction system is pressurized with hydrogen. The range of pressure is not limited as long as side reactions are not evoked, but a total pressure of 10 atm (gauge pressure) or less is sufficient, and the total pressure is usually 3 to 9 atm (gauge pressure). Supply of hydrogen to the reaction system
It is performed either intermittently or continuously while observing changes in the pressure gauge.

The reaction temperature in the present invention is usually in the range of room temperature to 150 ° C, preferably 50 to 120 ° C. If the reaction temperature is too high, side reactions tend to be evoked, while
If the temperature is too low, a satisfactory reaction rate cannot be obtained, which is not practical.

In the present invention, as a method for obtaining the target TMHA from the reaction solution, usually, after solid-liquid separation of the catalyst in the reaction solution,
TMHA in the concentrate obtained by evaporating the alcohol and water
The method of distilling off by vacuum distillation is adopted.

〔Example〕

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

Example 1 An autoclave having a volume of 1 equipped with a reflux condenser, a stirrer, a formalin supply pump, a thermometer, a gas inlet and a gas outlet was provided with 58.0 g (0.32 mol) of 65% HA aqueous solution, 111.0 g of methanol and 5% palladium. -Carbon powder (50
% Water product) 1.25 g [3.3 parts by weight of 5% palladium-carbon powder (50% water product) per 100 parts by weight of HA] were charged. The HA concentration at the time of charging was 22% (based on the total amount of HA, water and methanol charged), and the amount of methanol in the mixed solvent at the time of charging was 84% by weight (based on the total amount of water and methanol charged). It was.

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). Meanwhile, 113.0 g of 37% formalin aqueous solution [aqueous solution composition: HCHO4
1.8g (1.39mol), water 63.3g, methanol (stabilizer) 7.9
g] was added over 1.33 hours to carry out a reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 0.5 hours, cooled to 40 ° C, and the reaction liquid obtained by separating the catalyst was subjected to gas chromatography (G
As a result of analysis by the method C), both the HA conversion rate and the TMHA production rate with respect to the charged HA were 100%.

Example 2 In the same apparatus as in Example 1, HA crystals (anhydrous) 25.0 g (0.22 mol), 95% paraformaldehyde powder 28.6 g (0.90 mol), methanol 225.0 g and 5% palladium-carbon powder (50% hydrous product). 3.75g was charged. HA during preparation
The concentration was 10% (based on the total amount of HA, water, and methanol charged), and the amount of methanol in the mixed solvent at the time of charging was 99% (based on the total amount of water and methanol charged).

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). However, the reductive alkylation reaction was carried out for 3 hours.

After completion of the reaction, the reaction liquid obtained by cooling to 40 ° C. and separating the catalyst was analyzed by the GC method. As a result, the HA conversion was 100% and the TMHA production rate was 95.5%.

Example 3 The same apparatus as in Example 1 was charged with 70.0 g (0.39 mol) of 65% HA aqueous solution, 80.0 g of methanol and 4.50 g of 5% palladium-carbon powder (50% hydrous product). HA during preparation
The concentration was 30% (based on the total amount of HA, water and methanol charged), and the amount of methanol in the mixed solvent at the time of charging was 75% (based on the total amount of water and methanol charged).

The autoclave was replaced with nitrogen twice and replaced with hydrogen once, then heated to 80 ° C and hydrogen gas was introduced so that the hydrogen pressure was maintained at 8 to 9 kg / cm ² -G (gauge pressure). However, 140.0 g of 37% formalin aqueous solution [aqueous solution composition: HCHO5
1.8 g (1.72 mol), water 78.4 g and methanol (stabilizer) 9.8 g] were added over 1.25 hours to carry out the reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 0.5 hours, cooled to 40 ° C., and the catalyst was separately collected.

After that, except for the catalyst, the initial reaction conditions were used, and the catalyst was recycled by replenishing the recovered catalyst with 1/36 (0.125 g) of the charged amount of new catalyst. Done. As for the reaction results, the HA conversion rate and TMHA production rate were all 100%, and no deactivation tendency of the catalyst activity was observed.

Next, the reaction liquids of the above-mentioned five times of reductive alkylation reaction, that is, the first reaction to the first to fourth reaction of the catalyst recycling reaction are mixed and concentrated under reduced pressure using a rotary evaporator, and the obtained concentrated liquid is Further fractional distillation under reduced pressure, 121
290.1 g of a main distillate of ℃ / 60 mmHg was obtained. The purity of the obtained main fraction was 100% (GC method), and the TMHA production rate to the charged HA was 86.0%. The water content in the mixed reaction solution was measured by the Karl Fisher method, and as a result, the weight ratio of methanol to water was 40:60.

Example 4 HA crystal (anhydrous) 50.0 g (0.43 mol), ethanol 95.0 g and 5% platinum-carbon powder were placed in the same apparatus as in Example 1.
Charged 1.25g. HA concentration at the time of preparation was 35% (prepared H
(Based on the total amount of A and ethanol), and the reaction solvent was essentially 100% ethanol.

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). However, 138.0 g of 37% formalin aqueous solution [aqueous solution composition: HCHO5
1.1 g (1.70 mol), water 77.2 g and methanol (stabilizer) 9.7 g] were added over 1.75 hours to carry out the reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 0.5 hour, cooled to 40 ° C., and the reaction solution obtained by separating the catalyst was analyzed by GC. As a result, both the HA conversion rate and the TMHA production rate were 100%.

Example 5 The same apparatus as in Example 1 was charged with 58.0 g (0.32 mol) of 65% HA aqueous solution, 55.0 g of methanol and 2.50 g of 5% palladium-carbon powder (50% hydrous product). HA during preparation
The concentration was 33% (based on the total amount of HA, water, and methanol charged), and the amount of methanol in the mixed solvent at the time of charging was 72% (based on the total amount of water and methanol charged).

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). Meanwhile, 167.6 g of 25% formalin-water-methanol solution whose concentration was adjusted by diluting 37% formalin aqueous solution with methanol
[HCHO 41.9 g (1.40 mol), water 63.4 g and methanol 6
2.3 g] was added for 1.33 hours to carry out a reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 0.5 hour, cooled to 40 ° C., and the reaction solution obtained by separating the catalyst was analyzed by GC. As a result, both the HA conversion rate and the TMHA production rate were 100%.

Comparative Example 1 In the same apparatus as in Example 1, 76.9 g (0.43 mol) of 65% HA aqueous solution, 64.0 g of water and 5% palladium-carbon powder (5
2.50 g (0% water content) was charged. HA concentration at the time of preparation is 35%
(Relative to the total amount of HA and water charged), no alcohol was present in the reaction solvent.

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). However, 154.0 g of 37% formalin aqueous solution [aqueous solution composition: HCHO5
7.0 g (1.90 mol), 86.2 g of water and 10.8 g of methanol (stabilizer) were added over 1.5 hours to carry out a reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 1.5 hours, cooled to 40 ° C, and the reaction mixture obtained by separating the catalyst was analyzed by GC.
The production rate was 100% and the TMHA production rate was 44.2%.

Comparative Example 2 60.0 g (0.34 mol) of 65% HA aqueous solution in the same apparatus as in Example 1
And 5% palladium-carbon powder (50% hydrous product) 2.
Charged 50g. HA concentration at the time of preparation was 64% (prepared HA
And the total amount of water) and no alcohol was present in the reaction solvent.

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). However, 228.0 g of 19% formalin-water-methanol solution in which the concentration was adjusted by diluting 37% aqueous formalin solution with methanol
[HCHO 43.4 g (1.45 mol), water 65.7 g and methanol 11
8.9 g] was added for 1.92 hours to carry out a reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 0.5 hour, cooled to 40 ° C, and the reaction solution obtained by separating the catalyst was analyzed by GC.
The production rate was 100% and the TMHA production rate was 69.0%.

Comparative Example 3 HA crystal (anhydrous) 100 g (0.86 mol) in the same apparatus as in Example 1.
And 5% palladium-carbon powder (50% hydrous product) 2.
Only 50 g was charged, and alcohol and water were not charged as reaction solvents.

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). However, 307.0 g of 37% formalin aqueous solution [aqueous solution composition: HCHO1
13.6 g (3.78 mol), water 171.9 g and methanol (stabilizer) 21.5 g] were added for 4.0 hours to carry out the reductive alkylation reaction.

After completion of the reaction, the mixture was aged for 0.5 hours, cooled to 40 ° C., and the reaction solution obtained by separating the catalyst was analyzed by GC. As a result, the HA conversion was 100% and the TMHA production rate was 51.8%.

Comparative Example 4 The same apparatus as in Example 1 was charged with 70.0 g (0.39 mol) of 65% HA aqueous solution, 32.0 g of methanol, 48.0 g of water and 4.50 g of 5% palladium-carbon powder (50% water-containing product). HA concentration at the time of charging was 30% (based on the total amount of HA, water and methanol charged), and the amount of methanol in the mixed solvent at the time of charging was 30% (based on the total amount of water and methanol charged). It was.

After performing nitrogen replacement twice and hydrogen replacement once in the autoclave, raise the temperature to 100 ° C. and introduce hydrogen gas so as to maintain the hydrogen pressure of 8 to 9 kg / cm ² -G (gauge pressure). However, 133.5 g of 37% formalin aqueous solution [aqueous solution composition: HCHO4
The reductive alkylation reaction was carried out by adding 9.4 g (1.65 mol), water 74.8 g and methanol (stabilizer) 9.3 g] over 1.50 hours.

After completion of the reaction, the mixture was aged for 0.5 hours, cooled to 40 ° C., and the reaction solution obtained by separating the catalyst was analyzed by GC. As a result, the HA conversion was 100% and the TMHA production rate was 61.2%. As a result of measuring the water content by the Karl Fisher method, the weight ratio of methanol to water in the reaction solution was 19:81.

〔The invention's effect〕

According to the present invention, inexpensive hydrogen is used as a reducing agent instead of expensive formic acid, and a conventionally known noble metal catalyst, formylating agent, and hydrogen are further used without using an excessive basic organic acid and alkali. TMHA by reductive dimethylation used
Compared with the production method of, high-quality TMHA can be obtained in high yield even at a low reaction pressure. Therefore, the present invention is an excellent TMHA production method that can be industrially put to practical use.

Claims (1)

[Claims] 1. 1,6-Hexanediamine having 1 to 4 carbon atoms
In an aliphatic alcohol solvent or a mixed solvent of water and alcohol containing 30% by weight or more of the alcohol in the presence of a noble metal catalyst, N, N, N, N, characterized by reacting with formaldehyde and / or paraformaldehyde and hydrogen. Process for producing N ', N'-tetramethyl-1,6-hexanediamine.