KR100497168B1 - Recovery method of aliphatic aldehyde and method for preparing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate using the same - Google Patents

Abstract

The present invention relates to a method for recovering aliphatic aldehydes and a method for preparing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, in particular 2,2,4-trimethyl-1,3-pentanediol Distilling a mixture of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and a water-soluble by-product generated during the production process of monoisobutyrate to recover unreacted isobutylaldehyde. In the recovery method, prior to the distillation of the mixture relates to a method for recovering aliphatic aldehydes comprising the step of removing the alkali metal and organic acid salt by washing the aqueous by-products with washing water.

According to the present invention, alkali metals and organic acid salts remaining after the synthesis of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate can be effectively removed, and isobutyl aldehyde which is an unreacted raw material can be efficiently recovered. As a result, the yield of the entire process can be increased.

Description

Method for recovering aliphatic aldehyde and method for preparing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate using the same (2,2,4-TRIMETHYL-1,3-RECOVERY METHOD OF ALIPHATIC ALDEHYDE AND METHOD FOR PREPARING) PENTANEDIOL MONOISOBUTYRATE USING THE SAME}

The present invention relates to a method for recovering aliphatic aldehydes and a method for preparing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate using the same, more particularly isobutylaldehyde (isobutyraldehyde) and a variety of aliphatic aldehydes Method for recovering aliphatic aldehyde recovering unreacted isobutyl aldehyde generated when preparing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate using sodium hydroxide and 2,2,4 using the same It relates to a process for producing -trimethyl-1,3-pentanediol monoisobutyrate.

Glycol monoesters are widely used in the field of inks and coatings, as well as solvents for plasticizers, and are known to exhibit excellent physical properties as adhesives in the field of latex paints. Such glycol monoester is prepared through an aldol condensation reaction using an alkali metal hydroxide catalyst using aliphatic aldehyde having alpha hydrogen as a raw material. Aliphatic aldehydes with alpha hydrogen have a structural formula of RR'CHCHO, where R and R 'are lower alkyl groups of 1 to 4 carbon atoms, respectively. Examples of suitable aldehydes are isobutyl aldehyde, 2-methylbutyl aldehyde, 2-ethylbutyl aldehyde, 2-methylpentene aldehyde, 2-ethylpentene aldehyde, 2-ethylhexene aldehyde, 2-pentylpropion aldehyde, 2-cyclo Hexyl propion aldehyde and the like can be used. In addition, examples of alkali metal hydroxide catalysts include sodium hydroxide and potassium hydroxide.

The isobutylaldehyde is highly reactive and easily oxidized in air, producing various byproducts. Therefore, the isobutyl aldehyde, which is a reactant in the synthesis of the glycol monoester, is not converted to the glycol monoester, and the reaction is performed to obtain the maximum conversion rate at the time of minimizing the production of by-products. Alkali metal hyoxide used as a catalyst with various kinds of salts such as sodium salt or organic acid salt among the by-products generated after the reaction reacts with other substances at high temperature in the refining process to produce new by-products. In order to prevent the formation of these by-products, water has been added in the distillation process for recovering isobutylaldehyde. However, in this case, there is a loss of isobutyl aldehyde, which is a raw material, at the bottom of the column. Also, when a small amount of catalyst or salt is not removed and the next purification process is carried out, isobutyl aldehyde and by-products are continuously generated during the distillation by the catalyst or salt. Will affect the purity and yield. In addition, there is a further need for the process of removing the added water again before proceeding to the next purification process.

Conventionally known methods for recovering isobutyl aldehyde in 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate manufacturing process are as follows.

In order to recover isobutylaldehyde, U.S. Patent No. 5,180,847 distilled while maintaining the temperature at the bottom of the column at 95 ° C. and the temperature at the top of the column at 70 to 75 ° C. under reduced pressure of 20 torr. After distillation in the above method, the isobutylaldehyde at the top of the column is sent to an isobutylaldehyde supply tank, the material of the bottom is separated through the decanter, the water layer is separated, the organic layer is washed with water, and then the decanter is separated. Enter into the tablets. At this time, the water layer separated from the decanter is concentrated by using a packed column to recover the top bottom material (sodium isobutyrate) containing isobutyl aldehyde and sodium salt contained in the water layer. The method washed the organic material at the bottom of the column once after recovering isobutylaldehyde, which was purified in the next distillation process. However, the purity of the produced 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate product was found to be low as 91.5% by weight, and 7.3% by weight of 2,2,4-trimethyl-1 , 3-pentanediol diisobutyrate, 0.9 weight of 2,2,4-trimethyl-1,3-pentanediol and 0.3 weight percent of other impurities were included. The purity of the product was lowered because sufficient washing was not performed before the purification process, and various salts remaining in the organic layer acted as a catalyst at a high temperature during the purification process to decompose some products.

US Patent No. 4,883,906 discloses a method for recovering unreacted isobutylaldehyde after a reaction using a tubular reactor using a 40-stage distillation column. The process recovers isobutylaldehyde, which does not contain water, from the middle stage of the distillation column and recovers it, and some of the isobutylaldehyde contained in the water is sent to the top of the distillation column for disposal. In addition, 4 to 5.5% by weight of isobutyl aldehyde is not recovered at the bottom of the distillation column, and is transferred to the next step for disposal. However, in this method, the loss of isobutyl aldehyde which is a raw material in the isobutyl aldehyde recovery process, and 0.04% by weight of isobutyl aldehyde in the final product may cause odor.

US Patent No. 3,718,689 discloses a method in which a concentration of unreacted isobutylaldehyde reaches 32 to 75% by weight depending on experimental conditions after the reaction using a tubular reactor. In this method, unreacted isobutyl aldehyde was recovered from the column top using a distillation process. However, this method uses a method in which isobutylaldehyde trimer is generated during the distillation of isobutyl aldehyde, and vaporized water is injected into the distillation column for decomposition of this impurity. In addition, water containing sodium isobutyrate was obtained from the bottom of the isobutyl aldehyde distillation step, which was discarded, and a product from which the isobutyl aldehyde was removed at the middle of the distillation column was obtained. The method used a decanter separator to remove water from the final product, washed with water to remove various salts, and after separating the water with a decanter separator after washing, the remaining water and isobutyl aldehyde and The same small amount of low boiling point material was separated. Thereafter, 2,2,4-trimethyldi (isobutanoyloxy) pentane was separated by a flash column, diol by-products were removed from the purified column, and the final product was obtained from the purified column. However, the method did not mention the overall yield, and there is a disadvantage in that a further purification process is required for removing water and impurities contained in the product after washing by washing after isobutylaldehyde recovery process.

U.S. Patent No. 3,291,821 discloses an isobutylaldehyde recovery method in which 20% by weight of the reaction product from the reactor is an aqueous layer, which is separated in the first decanter. The remaining 80% by weight of the organic layer of the reaction product except the 20% by weight of the water layer contains 60% by weight of unreacted isobutyl aldehyde, which is recovered from the process of distilling isobutyl aldehyde. However, it has been pointed out that the aqueous layer contains water-soluble organic acid salts, including catalysts, most of which are sent back to the reactor, causing accumulation and side reactions of these salts. In the above method, various impurities including aldol and isobutylaldehyde trimer were synthesized during the distillation process, and water was added to the distillation process for the decomposition of the impurities, and azeotropic distillation of isobutylaldehyde with water was used. The patent on the process no longer mentions the purification part.

SUMMARY OF THE INVENTION In view of the problems of the prior art as described above, an object of the present invention is to provide a method for recovering aliphatic aldehyde, which does not lose isobutylaldehyde as a raw material and can prevent a decrease in yield by a catalyst and various salts after the reaction. do.

It is another object of the present invention to efficiently remove unreacted isobutylaldehyde by effectively removing alkali metals and organic acid salts remaining after the synthesis of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. It is to provide a recovery method of aliphatic aldehydes.

Another object of the present invention is to provide a method for preparing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate using the recovery method.

In order to achieve the above object, the present invention is a 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate that occurs during the manufacturing process of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate In the method of recovering aliphatic aldehyde comprising the step of recovering unreacted isobutyl aldehyde by distilling a mixture of water-soluble by-products,

It provides a method for recovering aliphatic aldehyde comprising the step of removing the alkali metal and organic acid salt by washing the water-soluble by-products with washing water before distillation of the mixture.

In addition, the present invention

(a) Washing the mixture of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and water-soluble by-products generated during the preparation of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate Washing with water to remove alkali metals and organic acid salts, followed by distillation to recover unreacted isobutylaldehyde; And

b) distilling and purifying the resultant obtained in step a).

It provides a method for producing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate comprising a.

Hereinafter, the present invention will be described in detail.

The present invention provides a method for efficiently recovering unreacted aliphatic aldehyde generated during the manufacturing process of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate without the loss of isobutyl aldehyde as a raw material, and 2 It is to provide a method for producing 2,4-trimethyl-1,3-pentanediol monoisobutyrate.

In general, when synthesizing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate using a base catalyst containing isobutylaldehyde and an alkali metal or an alkaline earth metal, various by-products are produced together with the reaction product after the reaction. The mixture is distilled to obtain the product 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate. As the base catalyst, sodium hydroxide is mainly used in consideration of economical efficiency. When sodium hydroxide is used as a catalyst, the by-products after the reaction are an unreacted raw material isobutylaldehyde, a by-product of unreacted catalyst sodium hydroxide, sodium salt, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, And other materials produced by denaturation of isobutylaldehyde. Therefore, in order to obtain only pure 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate as a product from the reaction product and the by-product mixture, a purification process for removing the by-product through distillation is required.

However, the order of purification becomes an important factor for efficient purification at this time. That is, it is desirable to first obtain a high purity product through a product purification process after the distillation process of recovering isobutyl aldehyde, which is a raw material, and alkali metals and organic acid salts such as sodium hydroxide and sodium salt. . At this time, the alkali metal and organic acid salt must be removed first because the residual catalyst and various salts react with the product to decompose the product when the solution containing them is distilled at a high temperature. The sodium hydroxide and salts are water soluble and can be removed from the reaction solution using water.

Therefore, in the present invention, the unreacted isobutylaldehyde can be efficiently recovered by removing the water-soluble by-products by using the wash water before the distillation process of the unreacted isobutylaldehyde.

Water is used as the washing water, and the amount of water used is preferably 5 to 50% by weight, more preferably 10 to 30% by weight based on the reaction solution.

In addition, the washing is not a one-time batch washing, but two or more divided washings, more preferably two to four washings, the concentration of sodium ions after washing is less than 100 ppm, preferably 1 to 100 ppm, more Preferably it is 1-20 ppm.

The wash water is fed to a mixed phase separator for separating the organic and water layers connected to the reactor, where the mixed phase separator is connected to an isobutylaldehyde distillation column.

When the unreacted isobutylaldehyde is distilled off, since the water-soluble by-products are removed, the unreacted isobutylaldehyde can be efficiently recovered without supplying additional water. The unreacted isobutyl aldehyde distillation column used in the present invention may use a 20-stage Oldshawshaw column connected to a pipe that recovers isobutyl aldehyde to the top and transfers other materials to the bottom. It is not limited. In addition, distillation conditions may be carried out while maintaining the temperature of the bottom of the column at 180 to 210 ° C, the top of the column at 40 to 50 ° C under reduced pressure of 450 torr, but is not limited thereto.

Therefore, when the above-mentioned method of recovering aliphatic aldehyde is used during the production process of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate, there is no isobutyraldehyde as a raw material and 2,2,4-trimethyl Very low content of -1,3-pentanediol, 2,2,4-trimethyl-1,3-pentanediol diisobutyrate and other organic components, up to 1% by weight, 2,2,4-trimethyl-1 A high purity product can be obtained in which the content of, 3-pentanediol monoisobutyrate is at least 99.0% by weight and at least 99.5% by weight.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following Examples are intended to illustrate the present invention, but are not limited thereto.

EXAMPLE

Example 1

10% by weight of wash water was added to the reaction solution based on 1000 g of the reaction solution containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and unreacted isobutylaldehyde, followed by stirring and standing. The washing process of separating the sodium hydroxide and sodium salts, which are the unreacted catalyst, separated by 3 was repeated three times. Sodium ions in the organic layer were measured using Orion's 960 model ion analyzer. As a result, the concentration of sodium ions was removed to 8 ppm after three washes.

Then, in order to recover isobutylaldehyde, which is a raw material in the organic layer obtained after washing, the reaction solution from which the sodium salt was removed was added to a distillation apparatus. The distillation column was a 20-stage Oldershaw column.

As a result of distillation while maintaining the temperature at the bottom of the column at 180 to 210 ° C. and the temperature at the top of the column at 40 to 50 ° C. under reduced pressure (450 torr), 100% by weight of the unreacted isobutyl aldehyde was reacted to the top of the column. The bottoms material was recovered and sent to the next refining process without the need for a decanter because the column bottoms did not contain water.

Comparative Example 1

40 wt% of wash water was added at a time based on 1000 g of the reaction solution containing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and unreacted isobutyl aldehyde after the reaction, followed by stirring and standing. As a result of measuring sodium ion in the inside, 100 ppm or more of sodium ion existed.

Thereafter, the washed organic layer was put in a distillation apparatus to recover isobutylaldehyde. At this time, as a result of distilling isobutyl aldehyde under the conditions of Example 1, impurities such as aldol and isobutyl aldehyde trimer were greatly increased, it was impossible to recover 100% by weight of isobutylaldehyde, and 3 to 5% by weight of There was a loss.

As described above, according to the present invention, alkali metals and organic acid salts remaining after the synthesis of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate can be effectively removed, and isobutyl aldehyde is an unreacted raw material. It can be efficiently recovered, thereby increasing the yield of the entire process.

Claims (5)

Unreacted by distilling a mixture of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and water-soluble byproducts generated during the preparation of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate In the method for recovering aliphatic aldehyde comprising the step of recovering the isobutyl aldehyde, Washing the water-soluble by-products with wash water before distillation of the mixture to remove the alkali metal and organic acid salt. The method of claim 1, wherein the washing is carried out until the concentration of sodium ions is 1 to 100 ppm. The method for recovering aliphatic aldehyde according to claim 1, wherein the washing water is divided into 2 to 4 times at 5 to 50 wt% based on the reaction solution. The method of claim 1, wherein said distillation is carried out without additional water supply. a) A mixture of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate and water-soluble by-products generated during the preparation of 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate is washed with water. Washing to remove alkali metals and organic acid salts, followed by distillation to recover unreacted isobutylaldehyde; And b) distilling and purifying the product of the bottom part of the distillation column obtained after distillation for recovering unreacted isobutylaldehyde in step a). Method for producing 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate comprising a.