JPS5854194B2 - Method for producing sebacic acid dimethyl ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for obtaining dimethyl sebacate from adipic acid monomethyl ester by an electrolytic condensation method, and purifying the same to efficiently and easily produce highly pure dimethyl sebacate. It is something.

The electrochemical condensation reaction of carboxylic acids is generally referred to as the Kolbe reaction.

This reaction produces sebacic acid dimethyl ester from adipic acid monomethyl ester in a methanol solution.

Methods for separating dimethyl sebacate from an electrolytic solution containing dimethyl sebacate include distillation, crystallization, and extraction.

However, the distillation method cannot be used as a separation method because dimethyl sebacate and monomethyl adipic acid form an azeotrope.

Furthermore, crystallization methods require operations to be carried out at low temperatures;
There is a drawback that contamination of hairdipic acid monomethyl ester in the crystals of sebacic acid dimethyl ester is unavoidable.

Therefore, conventional methods have been used to extract and separate the electrolyte by adding water, hexane, heptane, etc. to the electrolyte.

The main purpose of this extraction and separation is to separate the product dimethyl sebacate from the raw material monomethyl adipic acid.

However, in conventional methods, for example, if water is used as an extractant, a large amount of water must be used, and the difference in specific gravity between the oil and water layers after extraction is extremely small, making it difficult to separate the two layers. There were drawbacks.

Furthermore, when an organic solvent such as n-hebutane is used as an extractant, there is a drawback that a certain amount or more of adipic acid monomethyl ester is inevitably entrained in the n-hebutane layer.

The most recent production method (Publication of Patent Publication No. 50-89317) involves adding to the electrolyte an organic vehicle that ferments sebacate dimethyl ester but not water, and after a predetermined contact time, Although it has been possible to separate highly pure sebacic acid dimethyl ester using a relatively small amount of extraction solvent by separation, this method does not fundamentally solve the conventional drawbacks.

That is, it is unavoidable to introduce a new organic solvent into the system, and furthermore, in order to separate highly pure dimethyl sebacate, a certain amount or more of extraction solvent must be used. was there.

In order to overcome these drawbacks, the present inventors conducted intensive research and found that after removing methanol from the electrolyte, the remaining liquid was transferred to an anion tower filled with an anion exchange resin under conditions that contained as little methanol as possible. By passing the liquid through the resin, adipic acid monomethyl ester is adsorbed onto the resin, and extremely high purity sebacate dimethyl ester can be easily separated.Furthermore, the adipic acid monomethyl ester adsorbed on the resin can be easily separated with methanol or hot water. It was also discovered that the alkali metal salt of adipic acid monomethyl ester can be extracted and separated using a very small amount of water.

The present invention was made based on this knowledge, and provides a method for producing highly pure dimethyl sebacate without introducing a new organic solvent into the system or using a large amount of water. The purpose is to

That is, in the present invention, adipic acid monomethyl ester is electrolytically condensed to obtain an electrolytic solution containing sebacate dimethyl ester, and when separating sebacate dimethyl ester from this electrolytic solution, the electrolytic solution is filled with an anion exchange resin. The liquid is passed through the anion tower, and the adipate monomethyl ester is adsorbed onto the resin to separate it. Furthermore, the adipate monomethyl ester adsorbed on the resin is recovered by passing methanol or hot water through the anion tower, and the resin is regenerated. A method for producing sebacic acid dimethyl ester.

and (1) after removing methanol from the electrolytic solution, water is added, the mixed solution is separated into two layers, a water layer and an oil layer, and only the oil layer is passed through an anion column filled with an anion exchange resin; , pass the mixed solution through an anion tower, separate the effluent from the anion tower into two layers, a water layer and an oil layer,
The alkali metal salt of adipic acid monomethyl ester is extracted and separated from the aqueous layer, the adipic acid monomethyl ester is adsorbed and separated on the resin, and the adipic acid monomethyl ester adsorbed on the resin is transferred to an anion column with methanol or hot water. A method for producing sebacic acid dimethyl ester, which comprises passing a liquid through it, recovering it, and regenerating the resin.

It provides:

The electrolytic solution of the present invention comprises adipic acid monomethyl ester, its alkali metal salt, sebacate dimethyl ester, and adipic acid dimethyl ester which is a small amount of by-product thereof.
- A methanol storage solution containing methyl valeric acid, ω-hydroxy methyl valeric acid, methyl allyl acetate, etc.

In the present invention, the amount of water used to extract the alkali metal salt of adipic acid monomethyl ester from the electrolytic solution from which methanol has been removed may be at least the amount that can separate them into two layers after mixing them. Usually, the amount is preferably 5 to 50% by weight based on the electrolytic solution from which methanol has been removed.

The anion exchange resin used in the present invention includes a strongly basic anion exchange resin having a quaternary ammonium group as an exchange group;
Although it is a weakly basic anion exchange resin having a tertiary amine as an exchange group, when methanol is used as a regenerating agent, a weakly basic anion exchange resin is industrially advantageous in consideration of regeneration efficiency.

To specifically illustrate them, for example, Diamond ion W
A-10, 'WA-11, W-20.

WA-21, WA-30 (product name manufactured by Mitsubishi Chemical Industries, Ltd.), Amberlite IRA-68, lR45, IRA
-47, IRA-93, IRA94, Amberlist A
-21 (trade name manufactured by Rohm & Barth) and the like.

In the present invention, when adipic acid monomethyl ester is adsorbed onto a weakly basic anion exchange resin in an anion column, the presence of methanol hinders the adsorption, so it is necessary to suppress the presence of methanol as much as possible. It is preferable that the methanol concentrations in the inflow liquid to the anion tower and the residual liquid in the anion tower are each suppressed to 5% by weight or less.

The resin regenerating agent used in the present invention includes water or an organic sag agent having an affinity for water, such as methanol, ethanol, acetone, and tetrahydrofuran.

Industrially advantageous are methanol or hot water.

In particular, methanol is preferable since it has the advantage that methanol removed from the electrolyte can be used.

Considering the boiling point of the regenerant, the regeneration efficiency, the heat resistance of the resin, etc., the regeneration temperature is preferably in the range of room temperature to 60°C in the case of methanol, and in the range of 80 to 90°C in the case of hot water.

The liquid to replace the recycled resin used in the present invention includes water or an organic compound that has no affinity with water and does not adsorb to the resin;
Examples include adipic acid dimethyl ester and sebacic acid dimethyl ester.

However, when post-treatment and the like are taken into consideration, an electrolytic solution free of water or methanol/adipate monomethyl ester and its alkali metal salt is industrially advantageous.

Next, the present invention will be explained with reference to a flow sheet of drawings showing an example of the present invention. 1 is an electrolytic solution tank, 2 is an electrolytic cell, and the electrolytic solution is circulated between the electrolytic solution tank 1 and the electrolytic cell 2. be done.

A portion of the electrolyte in the electrolytic cell 2 is extracted and sent to the distillation column 3.

In the distillation column 3, methanol is removed, and the residual liquid is sent to the mixer 4 from the bottom of the column 3.

Water is sent from the supply port 5, thoroughly stirred, and then sent to the decanter 6.

An oil layer containing sebacic acid dimethyl ester and adipic acid monomethyl ester is extracted from the upper part of the decanter 6 and sent to the upper part of the anion column 7.

In the anion column 7, adipic acid monomethyl ester is adsorbed onto the resin, and a liquid mainly composed of sebacic acid dimethyl ester is extracted from the lower part of the column 7, which is further distilled to produce high-purity sebacic acid. Dimethyl ester is obtained.

The methanol distilled off from the upper part of the distillation column 3 is sent to the lower part of the anion column 7, where the adipic acid monomethyl ester adsorbed on the resin is recovered in methanol, and the methanol is transferred to the electrolyte tank 1.
It is circulated and subjected to an electrolytic reaction.

An aqueous layer containing an alkali metal salt of adipic acid monomethyl ester is extracted from the lower part of the decanter 6 and sent to a distillation column 8.

Water is distilled off from the top of the distillation column 8 and is reused for extraction.

The alkali metal salt of adipic acid monomethyl ester is extracted from the lower part of the distillation column 8, circulated to the electrolyte tank 1, and subjected to an electrolytic reaction.

As detailed above, according to the method of the present invention, by using an anion exchange resin, it becomes possible to separate dimethyl sebacate from the electrolytic solution without entrainment of monomethyl adipic acid, and furthermore, dimethyl sebacate By-products such as adipic acid dimethyl ester, n-valeric acid methyl ester, ω-hydroxyvaleric acid methyl ester, and allyl acetate methyl ester can be separated by distillation, for example.

Thus, in the conventional method, highly pure dimethyl sebacic acid ester cannot be obtained unless a certain amount or more of water and an organic solvent not present in the system are used, whereas in the method of the present invention, without using an organic solvent, Very high purity sebacic acid dimethyl ester can be obtained by using only a small amount of water to extract the alkali metal salt of adipic acid monomethyl ester.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 24% by weight of sebacic acid dimethyl ester as electrolyte
, 4% by weight of adipic acid monomethyl ester, 4.6% by weight of potassium salt of adipic acid monomethyl ester, and a small amount of adipic acid dimethyl ester as a by-product, n
- Using a stored methanol solution containing methyl valerate, ω-hydroxy methyl valerate, methyl allyl acetate, etc., methanol was removed from this electrolyte by distillation, reducing its concentration to 2.5% by weight. .

Next, add 250g of water to 250g of the electrolyte from which methanol has been removed.
After adding gr and stirring at room temperature, the mixture was separated into two layers.

The upper layer was an oil layer containing sebacic acid dimethyl ester and adipic acid monomethyl ester, and the lower layer was an aqueous layer containing potassium salt of adipic acid monomethyl ester.

The concentration of methanol in the oil layer was 1.5% by weight.

Next, methanol/adipate monomethyl ester and its potassium salt were removed from 100 ml (water basis) of a weakly basic anion exchange resin, Diaion WA-30 (manufactured by Mitsubishi Chemical Industries, Ltd., trade name), which had been regenerated into an OH type. The electrolyte solution was replaced with
h, with jacket).

200g of the oil layer from which the potassium salt of adipic acid monomethyl ester described above has been removed is passed through the anion column in a downward flow at room temperature at a flow rate of SV1. It was flushed with O.

The concentration of adipic acid monomethyl ester is 0.05% by weight
(This concentration is defined as the concentration at the flow-through point) The volume of effluent that is less than or equal to 165 gr and the flow-through exchange capacity is 0
．． 711J&1ll-resin.

The average concentrations of sebacic acid dimethyl ester and adipic acid monomethyl ester in this effluent are shown in Table 1.

Note that the flow-through exchange capacity is the amount of liquid WA that has flowed out up to the flow-through point.
27. Amount of resin replacement liquid WB 1 gr of adipic acid monomethyl ester Concentration of adipic acid monomethyl ester in the oil layer from which the potassium salt was removed CA weight % 1 Resin amount (based on water) ■ml Calculated according to the following formula.

Next, while passing hot water at 60°C through the jacket of the anion tower, 250°C of methanol, which had been preheated to 60°C, was added.
d was passed through the anion tower in an upward flow at a flow rate of SV 1.5, and the residual liquid in the anion tower was extruded and the adipic acid monomethyl ester adsorbed on the resin was desorbed.

The amount of adipic acid monomethyl ester recovered in the effluent was 17 gr, giving a recovery rate of 81%.

The recovery rate is defined as: amount of adipic acid monomethyl ester recovered in the effluent Wc 1 gr in the residual liquid in the anion column Amount of adipic acid monomethyl ester WD2 r1 Amount of adipic acid monomethyl ester adsorbed on the resin "F" It was determined from gr using the following formula.

Next, after cooling the anion tower to room temperature, methanol
150 gr' of an electrolytic solution from which adipic acid monomethyl ester and its potassium salt had been removed was passed through an anion column in an upward flow at room temperature at a flow rate of SV1.5 to extrude methanol.

The concentration of methanol in the effluent decreased to 4.5% by weight.

Next, 200 gr of the oil layer from which the potassium salt of adipic acid monomethyl ester described above had been removed was again passed through the anion tower in a downward flow at room temperature at a flow rate of svi,o.

The amount of liquid that flowed out to the flow-through point was 166 gr, and the flow-through exchange capacity was 0.72 eq/11-resin.

The average concentrations of sebacic acid dimethyl ester and adipic acid monomethyl ester in this effluent are shown in Table 1.

Note that the purity is determined by the concentration C of adipic acid monomethyl ester.
B. It was determined from the concentration Co of sebacate dimethyl ester using the following formula.

Furthermore, adipic acid monomethyl ester and sebacic acid dimethyl ester were analyzed by gas chromatography.

Example 2 The weakly basic anion exchange resin of Example 1 was mixed with Diaion W.
The same operation as in Example 1 was performed except that A-30 was changed to WA-20 (both manufactured by Mitsubishi Chemical Industries, Ltd., trade names).

The results are as follows.

(1) In the adsorption process, the amount of liquid flowing out up to the flow-through point was 158 gr, and the flow-through exchange capacity was 0.66 eq/#
- It was a resin.

The purity of sebacic acid dimethyl ester in this effluent is 9
It was 9.9% or more.

(2) During the regeneration process, the amount of adipic acid monomethyl ester recovered in the effluent was 18 gr, and the recovery rate was 85%.

(3) In the re-adsorption process, the amount of liquid flowing out up to the flow-through point was 153 gr, and the flow-through exchange capacity was 0.62 eq/
l)-resin.

The purity of sebacic acid dimethyl ester in this effluent is 9
It was 9.9% or more.

Example 3 The same operation as in Example 1 was performed except that the regeneration temperature in Example 1 was changed from 60°C to 20°C.

The results are as follows.

(1) In the adsorption process, the amount of liquid flowing out up to the flow-through point was 166 gr, and the flow-through exchange capacity was 0.72 eq/A.
- It was a resin.

The purity of sebacic acid dimethyl ester in the effluent was 99.
It was over 9%.

(2) During the regeneration process, the amount of adipic acid monomethyl ester recovered in the effluent was 16 gr, and the recovery rate was 70%.

(3) In the re-adsorption process, the amount of liquid flowing out up to the flow-through point was 158 gr, and the flow-through exchange capacity was 0.66 eq/
It was A-resin.

The purity of sebacic acid dimethyl ester in the effluent was 99.
It was over 9%.

Example 4 The same electrolyte as in Example 1 was used, and in the same manner as in Example 1, methanol was removed from the electrolyte and potassium salt of adipic acid monomethyl ester was extracted and separated into the aqueous layer.

Next, a weakly basic anion exchange resin regenerated into an OH type, Diaion WA-30 (manufactured by Mitsubishi Chemical Industries, Ltd., trade name) 100rrLl (water standard), was replaced with water, and a column (inner diameter 151 mφ x 1000 m with oil jacket) was replaced with water. ) was filled.

A 195 gr oil layer from which the potassium salt of adipic acid monomethyl ester had been removed was passed through the anion column in a downward flow at room temperature at a flow rate of svi,o.

The effluent was separated into two layers, the upper layer being an oil layer containing sebacic acid dimethyl ester, and the lower layer being an aqueous layer.

The amount of oil layer that has flowed out up to the point of flow through is 100 gr,
The flow-through exchange capacity was 0.73 eq/l)-resin.

The purity of sebacic acid dimethyl ester in this oil layer is 99
．． It was over 9%.

Next, in the same manner as in Example 1, the residual liquid in the anion column was extruded and the adipic acid monomethyl ester adsorbed on the resin was desorbed.

The amount of adipic acid monomethyl ester recovered in the effluent was 17 gr, giving a recovery rate of 80%.

Next, after cooling the anion tower to room temperature, 15
0TLl was passed through the anion tower in an upward flow at a flow rate of SV1.5 to extrude methanol.

The concentration of methanol in the effluent decreased to 0.1% by weight.

Next, 195 gr of the oil layer from which the potassium salt of adipic acid monomethyl ester had been removed was again passed through the anion tower in a downward flow at room temperature at a flow rate of SV 1.0.

The effluent was separated into two layers, the upper layer being an oil layer containing sebacic acid dimethyl ester, and the lower layer being an aqueous layer.

The amount of oil layer that flowed out up to the mass flow point was 101 gr, and the flow-through exchange capacity was Q, 73 eq/l-resin.

The purity of sebacic acid dimethyl ester in this oil layer is 99
, more than 9%.

Example 5 In the regeneration process of Example 4, the temperature of the water flowing into the jacket of the anion tower was changed from 60°C to 90°C, and the regenerating agent was changed from methanol at 60°C to hot water at 90°C. The same operation as in Example 4 was performed.

The results are as follows. (1) In the adsorption process, the amount of oil layer that flowed out up to the flow-through point was 102 gr, and the flow-through exchange capacity was Q, 75 eq/l-resin.

The purity of sebacic acid dimethyl ester in this oil layer is 99
．． It was over 9%.

(2) During the regeneration process, the amount of adipic acid monomethyl ester recovered in the effluent was 16 gr, and the recovery rate was 70%.

(3) In the re-adsorption process, the amount of oil layer that has flowed out up to the flow-through point is 89 gr, and the flow-through exchange capacity is 0.65 eq/
It was A-resin.

The purity of sebacic acid dimethyl ester in the oil layer is 99.9.
% or more.

Example 6 The same electrolytic solution as in Example 1 was used, and methanol was removed from this electrolytic solution.

Next, 100 ml (based on water) of a weakly basic anion exchange resin, Diaion WA-30 (manufactured by Mitsubishi Chemical Industries, Ltd., trade name), which had been regenerated into an OH type, was replaced with water, and a column (inner diameter 15iπφ (with jacket).

In this anion tower, an electrolytic solution 180 from which methanol has been removed
A mixture of 20 gr of water and 20 gr of water was passed through the mixture in a downward flow at room temperature while sufficiently stirring at a flow rate of SV1. It was flushed with O.

The effluent separated into two layers, the upper layer being an oil layer containing sebacic acid dimethyl ester and the lower layer being an aqueous layer containing potassium salt of adipic acid monomethyl ester.

The amount of oil layer that has flowed out up to the flow-through point is 75 gr, and the flow-through exchange capacity is 0.55 eq/l! - It was a resin.

Next, in the same manner as in Example 1, the residual liquid in the anion column was extruded and the adipic acid monomethyl ester adsorbed on the resin was desorbed.

The amount of adipic acid monomethyl ester recovered in the effluent was 17 gr, giving a recovery rate of 88%.

Next, in the same manner as in Example 4, methanol in the anion column was extruded.

Next, 200 gr of a mixed solution of water and the electrolytic solution from which methanol has been removed are added to the anion tower that has been replaced with recycled water.
is passed in a downward flow at room temperature with sufficient stirring at a flow rate of SV1.
．． The solution was again flushed with O.

The effluent was separated into two layers: the upper oil layer contained sebacic acid dimethyl ester, and the lower aqueous layer contained potassium salt of adipic acid monomethyl ester.

The amount of oil layer that flowed out up to the flow-through point was 77 gr, and the flow-through exchange capacity was 0.57 eq/73-resin.

The purity of sebacic acid dimethyl ester in this oil layer is 99
．． It was over 9%.

[Brief explanation of drawings]

The drawing is an example of a flow sheet for implementing the present invention, and in the drawing, 1 is an electrolyte tank, 2 is an electrolytic tank, 3 is a distillation column, 4 is a mixer, 5 is a water supply port, and 6 is a decanter 17 is an anion column, and 8 is a distillation column.

Claims (1)

[Claims] 1 Adipic acid monomethyl ester is electrolytically condensed to obtain an electrolytic solution containing sebacate dimethyl ester, and when separating sebacate dimethyl ester from this electrolytic solution, the electrolytic solution is filled with an anion exchange resin. The liquid is passed through the anion tower, and the adipate monomethyl ester is adsorbed onto the resin to separate it. Furthermore, the adipate monomethyl ester adsorbed on the resin is recovered by passing methanol or hot water through the anion tower, and the resin is regenerated. A method for producing sebacic acid dimethyl ester. 2. The method for producing dimethyl sebacate according to claim 1, wherein the anion exchange resin is a weakly basic anion exchange resin. 3. Production of sebacic acid dimethyl ester according to claim 1, wherein the anion exchange resin is a weakly basic anion exchange resin, and the concentration of methanol in the adsorption stock solution passed to the anion column is 5% by weight or less. Method. 4. The method for producing dimethyl sebacate according to claim 1, wherein the regeneration of the resin with methanol is carried out at a temperature of room temperature to 60°C. 5. The method for producing dimethyl sebacate according to claim 1, wherein the regeneration of the resin with hot water is carried out at a temperature of 80 to 90°C. 6. The method for producing dimethyl sebacate according to claim 1, wherein the regeneration solution remaining in the anion column is replaced with water or an electrolytic solution from which methanol/adipate monomethyl ester and its alkali metal salt have been removed. 7 Adipic acid monomethyl ester is electrolytically condensed to obtain an electrolytic solution containing sebacate dimethyl ester, and when separating sebacate dimethyl ester from this electrolytic solution, methanol is removed from the electrolytic solution, water is added, and the mixture is Separate the liquid in advance into two layers, a water layer and an oil layer, and pass only the oil layer through an anion tower filled with anion exchange resin, or
Alternatively, the mixed solution is passed through an anion tower, the effluent from the anion tower is separated into two layers, an aqueous layer and an oil layer, and the alkali metal salt of adipic acid monomethyl ester is extracted and separated from the aqueous layer, A sebacin characterized by adsorbing and separating adipic acid monomethyl ester onto a resin, and further recovering the adipic acid monomethyl ester adsorbed onto the resin by passing methanol or hot water through an anion column to regenerate the resin. Method for producing acid dimethyl ester. 8. Claim 8, wherein the amount of water added for extraction is 5 to 50% by weight based on the electrolytic solution from which methanol has been removed.
A method for producing sebacic acid dimethyl ester as described in . 9. The method for producing dimethyl sebacate according to claim 8, wherein the anion exchange resin is a weakly basic anion exchange resin. 10. Production of dimethyl sebacate according to claim 8, wherein the anion exchange resin is a weakly basic anion exchange resin, and the concentration of methanol in the adsorption stock solution passed to the anion column is 5% by weight or less. Method. 11. The method for producing dimethyl sebacate according to claim 8, wherein the methanol used to regenerate the resin is methanol removed from the electrolyte. 12. The method for producing dimethyl sebacate according to claim 8, wherein the regeneration of the resin with methanol is carried out at a temperature of room temperature to 60°C. 13. The method for producing dimethyl sebacate according to claim 8, wherein the regeneration of the resin with hot water is carried out at a temperature of 80 to 90°C. 14. The method for producing dimethyl sebacate according to claim 8, wherein the regeneration liquid remaining in the anion column is replaced with water or an electrolytic solution from which methanol/adipate monomethyl ester and its alkali metal salt have been removed. .