JPS58161784A - Manufacture of dimethyl thapsate - Google Patents

Abstract

PURPOSE:To carry out electrolysis until monomethyl adipate and monomethyl dodecanedioate are practically used up when dimethyl thapsate is manufactured, by electrolytically condensing the compounds, by carrying out electrolysis for a fixed time, adding the former compound, and continuously carrying out electrolysis. CONSTITUTION:A mixture of monomethyl dodecanedioate with 0.5-2.0 times as much monomethyl adipate as monomethyl dodecanedioate by mole is electrolytically condensed in a soln. of alkali metallic salts of the compounds in methanol by a batch system for a fixed time. Monomethyl adipate is then added, and electrolysis is continuously carried out. Thus, a sudden voltage rise which makes the succession of electrolysis impossible is prevented in the latter half of electrolysis. Accordingly, dimethyl thapsate can be manufactured industrially advantageously.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel industrial method for producing dimethyl tabsinate. More specifically, the present invention relates to a method for producing dimethyl niophthapsinate by cross-Kolbe electrolytic condensation of monomethyl adipate and monomethyl dodecanoate.

Dimethyl tabsinate has an extremely wide range of uses as a raw material for perfumes, various polymers, plasticizers, etc. It is particularly useful as a raw material for macrocyclic musk fragrances.

The following methods have been proposed for producing tabsic acid and its esters. Various methods have been proposed, including a method for producing it using Fenton's reagent using cyclohexanone and olefin as raw materials, and a fermentation method for converting n-alkane or monocarboxylic acid into dibasic acid using yeast. However, all of these methods have problems such as extremely long reaction steps, use of special reagents, and low yields, and are still not sufficient as industrial production methods. In addition, a method for producing tabsic acid diester from azelaic acid monoester by Kolbe electrolytic reaction was published in
No. 8-11116, Oil Chemistry.

12.669 (1963), etc. However, this method requires separation into an anode chamber and a cathode chamber using a cation exchange membrane, and a cation exchange membrane is used to create a value for the water concentration in the anolyte of 30 to 40% by weight. Therefore, there are problems such as the device being an AM device and extremely low current efficiency, etc., and it cannot be said to be a sufficient method for industrial production. Research has been actively conducted on methods for electrolytically condensing adipic acid monoester, and various findings have been obtained. That is, the present inventors previously described a detailed industrial implementation method in Japanese Patent Application Laid-Open No.
This method is disclosed in Japanese Patent Application Laid-Open No. 158285, Japanese Patent Application Laid-open No. 56-44782, and the like. However, when applying this technology to produce dimethyl tabsinate from monomethyl adipate and monomethyl dodecane, a sudden voltage rise occurs in the latter half of electrolysis, making electrolysis impossible and unreacted monomethyl adipate and dodecane. A large amount of monomethyl acid remains. The presence of monomethyl adipate and monomethyl dodecanoate complicates the rounding device for separating monomethyl adipate and monomethyl dodecanoate in the purification of dimethyl tabucinate in the subsequent step, and also causes loss of monomethyl adipate and monomethyl dodecanoate. There is a problem in that it leads to a decrease in the product purity of dimethyl tabsinate.

The inventors of the present invention have conducted intensive research to provide an industrially advantageous manufacturing method that can solve all the problems of the various methods proposed to date. Applying the electrolytic method proposed by the inventors for producing dimethyl sepacate from monomethyl adipate, monomethyl adipate in the charging solution was made 05 to 2.0 times the mole of monomethyl dodecanoate and electrolyzed for a certain period of time. It has been found that by subsequently adding monomethyl adipate and continuing electrolysis, it is possible to prevent a sudden rise in voltage that would make it impossible to continue electrolysis.

The present invention has been made based on the above-mentioned knowledge, and it is possible to industrially advantageously produce dimethyl tabsinate by suppressing a sudden voltage increase and carrying out electrolysis until adipic monomethyl and monomethyl dodecanoate are substantially eliminated. The purpose of this invention is to provide a method for manufacturing.

The method for producing dimethyl tabsinate of the present invention which achieves the above object is to add a mixture of monomethyl dodecanoate and monomethyl adipate in an amount of 0.5 to 2.0 times the mole of monomethyl dodecanetriate to their alkali metal salts. The method is characterized in that electrolytic condensation is carried out in batches for a certain period of time in a methanol solution containing methane, and then monomethyl adipate is further added and electrolyzed.

Details of the method of cross-Kolbe electrolytic condensation of monomethyl adipate and monomethyl dodecanoate to dimethyl tabsinate according to the present invention are as follows.

The ratio of monomethyl adipate and monomethyl dodecanoate at the time of charging in the present invention has a large effect on the electrolytic voltage. If monomethyl adipate is less than 0.5 times the mole of monomethyl dodecanoate, a voltage rise will occur after the start of electrolysis, making electrolysis impossible.

When monomethyl adipate is 0.5 times mole or more relative to monomethyl dodecanoate, electrolysis can be carried out without voltage increase. Further, as the proportion of monomethyl adipate increases, the electrolytic voltage decreases, which is preferable. However, as the proportion of monomethyl adipate increases, the amount of by-product dimethyl sebacate produced increases, and the amount of dimethyl tabsinate produced decreases. From the above, it is necessary that monomethyl adipate be present in an amount of 0.5 to 2 moles relative to monomethyl dodecanoate.

The present invention applies the above-mentioned electrolysis method for producing dimethyl sebacate from monomethyl adipate, in which unreacted monomethyl adipate and In order to prevent monomethyl dodecanoate from remaining, it is necessary to add monomethyl adipate to the electrolytic solution after electrolysis for a certain period of time and conduct electrolysis until monomethyl adipate and monomethyl dodecanoate are substantially eliminated. That is, the addition of monomethyl adipate into the electrolytic solution is carried out before the chamber voltage rises, and electrolysis is then carried out, but monomethyl adipate may be added after the voltage rises and electrolysis is carried out again. The addition of monomethyl adipate is preferably carried out when the monomethyl dodecanoate concentration is approximately 2% by weight or more at the time the voltage increases.
It is more preferable to carry out the reaction at less than -weight.

The amount of monomethyl adipate added in the present invention is such that the amount of monomethyl adipate and its alkali metal salt after addition is 3 to 8 times the mole of unreacted monomethyl dodecanoate and its alkali metal salt. is preferable, and 5 to 7 times the molar amount is more preferable. Below 3 times the mole, a rapid voltage increase occurs again and unreacted monomethyl dodecanoate and monomethyl adipate remain. At 8x/1 liter or more, the production of dimethyl sebacate other than the main product increases.

The solution in which electrolytic condensation is carried out in the present invention is a methanol solution containing the raw materials monomethyl adipate and monomethyl dodecanedioate and their neutralized salts, and the products dimethyl tabsinate, dimethyl sebacate, and dimethyl docosaniate. , and other rigid organisms. In the case of hot water in a methanol solution, if the water concentration can be extremely reduced during electrolytic condensation, the current efficiency will not be extremely rapid.
．． If the concentration exceeds 5% by weight, the material yield and current efficiency will also deteriorate. Therefore, in order to maintain high material yield and current efficiency, it is necessary to maintain the water concentration in the range of 0.15 to 3.5 wt.

The electrolytic condensation of the present invention may be carried out batchwise for monomethyl adipate and monomethyl dodeca/diaate, which are the raw materials, until the voltage rises in the latter half or before the voltage rises. The concentration of monomethyl dodecanoate and monomethyl dodecanoate may be maintained at a constant concentration for a certain period of time and then carried out continuously, and then carried out batchwise until the time when the voltage increases in the latter half or before the voltage increases.

Considering the separation and purification of the product in the subsequent step, the electrolytic condensation after addition of monomethyl adipate is preferably continued until the concentration of monomethyl adipate and monomethyl dodecanoate becomes 0.5% by weight or less.

The mixed acid of monomethyl adipate and monomethyl dodecanoate used in the electrolytic reduction of the present invention is used in an amount of 10 to 50 kg by weight. Concentrations higher than 50 wt- will result in higher voltages, concentrations lower than 10 wt- will result in poor volumetric efficiency;
Furthermore, current efficiency also deteriorates.

In the present invention, hydroxides, carbonates, bicarbonates, methylates, ethylates, or aquines of lithium, potassium, and sodium are used as neutralizing bases to increase the conductivity of the solution during electrolytic condensation. It will be done. However, amines are oxidized at the anode and accelerate the consumption of the anode, and the use of lithium compounds deteriorates current efficiency. Therefore, it is desirable to use sodium and potassium hydroxides, carbonates, bicarbonates, and methylates. In addition, the degree of neutralization (defined as the molar ratio of the mixed acid to be neutralized with the base) during the preparation of the mixed acid of monomethyl adipate and monomethyl dodecanoate is 2 to 50.
Morti is preferred. If the degree of neutralization is less than 2 molar, the voltage will still be low, and if the concentration is higher than 50 molar, the current efficiency will be low.

The electrolytic cell used in the present invention is one commonly used in organic electrolytic reactions.1! Any material may be used as long as the solution can be passed between the two electrodes at a high flow rate. For example, an electrolytic cell has a cathode plate and an anode plate facing each other in parallel, with a polypropylene plate between the two electrodes defining the electrode spacing. This polypropylene plate has an opening in the center so that the electrolyte can flow therethrough.

The current-carrying area of the electrodes depends on the size of the apertures, and the electrode spacing is determined by the thickness of the plate. The electrolytic solution enters through a supply port provided in the electrolytic cell, undergoes a reaction while passing between the two electrodes, exits through an outlet port, and is circulated to the electrolyte tank.

As for the electrode materials used in the electrolytic condensation of the present invention, platinum, rhodium, ruthenium, iridium, etc. are used singly or in an alloy for the anode, and are usually used as plating, and titanium, taftal, etc. are used for the plating substrate. used. Further, the cathode preferably has a low hydrogen overvoltage, but is not particularly limited, and platinum, iron, stainless steel, titanium, etc. can be used.

The flow rate of the electrolytic solution in the electrolytic cell is 1 to 4 g/sec. If the flow rate is higher than 4 g/sec, the pressure loss in the electrolytic cell increases. The spacing between the electrodes is preferably 0.5 to 3 m.

If it is less than 0.5■, the pressure loss inside the electrolytic cell will be large, and if it is less than 3■
The wider it is, the higher the voltage will be. The current density is preferably 5 to 40 m/dm, and if it is less than 5 A/d-, the current efficiency will be low. The temperature of the electrolyte is preferably 45-65°C.
If the temperature is lower than 45° C., the current efficiency will be low and the voltage will be high, and in some cases, products will precipitate. Temperatures higher than 65°C are limited by the boiling point of the electrolyte.

After the electrolytic condensation is completed, the product can be separated from the electrolyte by a conventional method. That is, after methanol is removed from the electrolyte, it is directly separated into two oil-water layers, or water is added to separate the two layers, and the oil is distilled to produce high-purity dimethyl tabsinate, dimethyl sebacate, and dimethyl docosaniate. can be obtained.

As detailed above, the method of the present invention has the following advantages over conventional methods and various other proposed methods. First, the inventors proposed lζ
Applying the technology for manufacturing dimethyl sebacate, adding monomethyl adipate after electrolysis for a certain period of time and continuing electrolysis, it is possible to substantially eliminate monomethyl dodecanoate and monomethyl adipate. Like the manufacturing method, it can be easily manufactured. Second, by electrolytic condensation, dimethyl sebacate and dimethyl docosaniate can be simultaneously obtained in addition to the target dimethyl tabsinate. These include target products as well as fragrances,
It is useful as a raw material for various polymers, plasticizers, etc., and has an extremely wide range of uses. Thirdly, no special chemicals or chemicals that pose safety issues are used. Fourth, the desired product can be obtained with high current efficiency and high material yield.

Example 1 Monomethyl adipate, monomethyl dodecanoate and their respective potassium salts were placed in the electrolyte tank, and the water content was 9.84ii11%, 15.0%, 1.35wt - 11.93wt - 13.0wt. Weight -, the amount of prepared liquid is 1
Methanol, potassium hydroxide, water, monomethyl adipate, and monomethyl dodeganate were added in this order to prepare a solution. This adjusted solution was circulated to the electrolytic cell.

The electrolytic cell has a current-carrying area of 1.0 clII x 10 occlII at both electrodes, and the cathode is a 2-inch thick titanium plate, and the anode is a 2-inch thick titanium plate plated with 4 micron platinum. The energized area is 1-, OcrrIXlookm
A polyethylene plate having a thickness of 1=+ and having an opening was placed so that the electrodes were held at a distance of 1 m.

The electrolytic cell used had a liquid supply port and a liquid outlet. The liquid was flowed between the electrodes at a flow rate of 2 m/@@c, and the current density was set to II.
In A/a-, electrolysis was carried out while maintaining the temperature of the liquid at 48 to 52°C. Also, 1 at the same time as electrolysis starts! Add 23% of each of monomethyl adipate and monomethyl dodecanedioate to the solution tank. "Og/Hr, 36.8 g/Hr was added continuously for 5 hours. After the addition was completed, the electrolyte was sampled and the residual concentration of monomethyl adipate and dodeca/monomethyl diaate was measured by gas chromatographic analysis before electrolysis was started. When the concentration reached 0.52 wt 1%, z, 6 wt s, monomethyl adipate was added to 150 g-[, and the electrolyte was subsequently sampled to determine the remaining concentration of monomethyl adipate and monomethyl dodecanoate. Electrolysis was carried out while measuring the amount, and the electrolysis was terminated when the concentration of soybean paste reached 0.03 wt. The energization time from the start to the end of electrolysis was 11
．． It was 96 hours. Electrolysis voltage is 12.8V to 8.9
It changed to v. Furthermore, when monomethyl adipate was added, the voltage increased from 9.5V to 10.0V at 9 points.

The amount of liquid at the end was 1227 g. After the electrolysis was completed, each component of the electrolyte was measured by gas chromatography, and the results were as follows:
The respective concentrations of dimethyl tabsinate, dimethyl docosaniate, and dimethyl sebacate are 14.6 wt - 17.5
The weight was 9 times and 11.7 times.

The material yield and current efficiency of each electrolytic condensation product were as follows.

(Margin below) Current efficiency (*) The material yield and current efficiency were calculated using the following formula.

Material yield of dimethyl sebacate based on monomethyl adipate Material yield of dimethyl tabsinate based on monomethyl adipate (based on monomethyl dodecanoate) Material yield of dimethyl docosaniate based on monomethyl dodecanoate Number of moles of dimethyl docosaniate produced ×2=
-X1
00 Consumed 9 Moles of monomethyl dodecanoate However, the composition ratio of the potassium salt of monomethyl adipate and the potassium salt of monomethyl dodecanoate at the end of electrolysis is the mole of monomethyl adipate and dodecane double-chain monomethyl after the addition of monomethyl adipate. It was compared. Further, the current efficiency was determined on the assumption that 1 mole of each product vlJ was generated from the amount of electricity of 2 faradays.

The same procedure was carried out in the following Examples.

Example 2 Electrolysis was started using the same preparations, the same electrolyzer, and the same electrolytic conditions as in Example 1. Simultaneously with the start of electrolysis, monomethyl adipate and monomethyl dodecanoate were continuously added to the electrolyte tank at 23.0 g/Hr and 36.8 g/Hr, respectively, for 7 hours. After the addition, electrolysis was performed while analyzing the concentration of monomethyl dodecanoate and monomethyl adipate in the same manner as in Example 1, and the respective concentrations were 2.4% by weight and 0.0% by weight.
When the weight reached 48%, add 20% of monomethyl adipate.
9 g was added at once and electrolysis was continued, and the electrolysis was terminated when the concentration of monomethyl dodecanoate and monomethyl adipate reached 0.044% by weight. Energization time Fiis,
It was o corner check. The electrolytic voltage ranges from 12.7 V to 9. O.V.
changed to. Also, when monomethyl adipate was added, the voltage increased from 9.3v to 11. It rose to OV. The amount of liquid at the end of electrolysis was 1348 g. After the electrolysis was completed, each component of the electrolyte was measured by gas chromatography, and the concentrations of dimethyl tabsinate, dimethyl docosaniate, and dimethyl sebacate were 16.2% by weight and 8.44% by weight, respectively.
It was 114.0% by weight. The material yield and current efficiency of each electrolytic condensation product were as follows.

Example 3 Same as Example 1! In the decomposition apparatus, the concentrations of monomethyl adipate, monomethyl dodecanoate, their respective potassium salts, and water were 14.8 wt., 1.15.0 wt.
Electrolysis was started under the same electrolytic conditions as in Example 1, with preparations made in the same manner as in Example 1 so that the amounts of the charged liquid were IKq at 96% by weight, 0.91% by weight, and 1.0% by weight.

At the same time as electrolysis starts, add 28.1g/h of monomethyl adipate and monomethyl dodecanoate to the electrolyte tank.
r, was added continuously for 5 hours at 30.0 g/Hr.

After the addition, the electrolyte was sampled and the remaining concentrations of monomethyl adipate and monomethyl dodecanoate were measured by gas chromatography while electrolysis was carried out until the concentration reached 1.
．． 1 weight iii%, 3.5 weight - Ajipi at the time of Natsu 9/
134.0 g of monomethyl acid was added at once, and electrolysis was performed while sampling the electrolytic solution and measuring the residual concentration of monomethyl adipate and monomethyl dodecanoate.
The process was terminated when the concentration reached 0.03% by weight. The energization time from the start to the end of electrolysis was 12.61 hours. Electrolysis voltage is 13.5V to 9. It changed to Ov.

Also, when monomethyl adipate was added, the voltage rose from 9.7V to 10.3V. The amount of liquid at the end was 1190 g.

After the electrolysis was completed, each component of the electrolyte was analyzed, and the concentrations of dimethyl tabsin, dimethyl docosaniate, and dimethyl sebacate were 15.7% by weight and 5.7% by weight, respectively.
They were 5% by weight and 14.6% by weight. The material yield and current efficiency of each electrolytic condensation product were as follows.

Material Yield (H) Current Efficiency (%) Example 4 In the same electrolytic apparatus as in Example 1, monomethyl adipate, monomethyl dodecanoate, their respective potassium salts, and water concentrations were 13.8% by weight and 30%. 0% by weight, 1.
89% by weight, 3.85% by weight 3.3-layer violet was prepared, and the same volume as in Example 1 was prepared so that the liquid volume was 1 kg, and electrolysis was started under the same electrolytic conditions as in Example 1. The 'It solution continued until the voltage rose, and at the point when the voltage rose, -asps was stopped. The current application time was 6.71 hours.

At this point, the concentrations of monomethyl adipate and monomethyl dodecanoate were 0.41 weight to 12.2 weight. 103 g of monomethyl adipate was added to this electrolytic solution and electrolysis was started again. The voltage suddenly increased 2.28 hours after restarting electrolysis. At this point, electrolysis was terminated. The amount of electrolyte was 937.7 g, and the concentration of each of monomethyl adipate and monomethyl dodecanoate was 0.02.
% by weight, 0.29% by weight. In addition, the respective concentrations of dimethyl tapunate, dimethyl sebacate, and dimethyl docosaniate were ts, O1t, 8.41% by weight, 11
．． 6 weight.

The material yield and current efficiency of each electrolytic condensate were as follows.

(Remains below) Material Yield (H) Comparative Example 1 Monomethyl adipate, monomethyl dodecanoate, their respective potassium salts, and water concentrations were 5.9% by weight and 30.0% by weight, respectively, in the same electrolytic apparatus as in Example 1. Weight - 10,8
1 weight t-13,851 ([% 3.2'1ffit%, the amount of liquid was charged to 1k as in Example 1, and electrolysis was started under the same electrolytic conditions as Example 1. .At the same time as the electrolysis starts, the voltage starts to rise, and after the electrolysis starts, the voltage starts to rise.
Within minutes, the voltage rose rapidly and it became impossible to continue electrolysis.

Patent applicant: Asahi Kasei Industries, Ltd.

Claims (1)

[Claims] 1. A mixture of monomethyl dodecanoate and monomethyl adipate in an amount of 0.5 to 2.0 times the mole of monomethyl dodecanoate is batchwise prepared for a certain period of time in a methanol solution containing an alkali metal salt thereof. A method for producing dimethyl tabsinate, which is characterized by electrolytic combination, followed by electrolysis by cooling monomethyl adipate to the east, and the concentration of monomethyl dodecanoate in the km solution is about 2 times 1
The method 3 according to claim 1, wherein monomethyl adipate is added at the time of electrolytic condensation until the concentration of monomethyl dodecanoate is about 2 to 4.
Claim 2: Adding monomethyl adipate at the time of electrolytic condensation to reach the range of t. Method 5 according to claims 1 and 2, in which the amount of monomethyl adipate and alkali metal salt is in the range of 3 to 8 times the molar amount relative to monomethyl dodecanedioate and its alkali metal salt, constant. The amount of monomethyl adipate to be added after time electrolytic condensation is 5 to 7 times the amount of monomethyl adipate and its alkali metal salt relative to unreacted monomethyl dodecanedioate and its alkali metal salt in the electrolytic solution. 6. The water concentration in the methanol solution during electrolytic shrinkage is 0.1.
The method according to claim 1, characterized in that the amount is maintained at 5 to 3.5% by weight.