KR20070009104A - Co-production method of carboxylic acid and its ester compound - Google Patents

Abstract

Provided is a method for co-producing carboxylic acid and a ester compound, which enhances yield and selectivity of the ester compound by using alcohol as a catalyst and reactant and produces the products in a rapid, simple, and economical manner. The method for co-producing carboxylic acid and a ester compound comprises a step of subjecting a primary aldehyde compound to oxidation in the presence of an oxidizer and alcohol. The aldehyde compound has 1-20 carbon atoms. The oxidizer is oxygen. The alcohol has 1-10 carbon atoms. A mole number of the alcohol is 5-200% based on the mole number of the primary aldehyde compound. The reaction is performed at a temperature of 10-100‹C under a pressure of 1-10 atmospheres.

Description

Co-production method of carboxylic acid and its ester compound

1 is a process chart showing one embodiment of a method for producing a carboxylic acid and an ester compound by a conventional method.

Figure 2 is a process chart showing a method for producing a carboxylic acid and ester compound according to the production method of the present invention.

<Explanation of symbols for the main parts of the drawings>

10: aldehyde 11: oxygen

20: carboxylic acid 21: alcohol

31: ester compound 40: primary aldehyde compound

41: alcohol 42: oxidizing agent

44: water 48: carboxylic acid

52 ester compound 100 reactor

110: low boiling point impurity removal column 120: high boiling point impurity removal column

200: esterification reactor 210, 220, 230, 240: distillation column

300 reactor 350 reaction distillation column

400: primary low boiling point removal column 410: carboxylic acid cut column

420: secondary low boiling point removal column 430: ester compound distillation column

FIELD OF THE INVENTION The present invention relates to a process for the parallel production of carboxylic acid and ester compounds, and more particularly, to a process for producing carboxylic acid and ester compounds simultaneously, quickly and simply and more economically.

Carboxylic acid and ester compounds are used in a wide variety of applications in the chemical industry. For example, 2-ethylhexanoic acid, one of carboxylic acids, is used as a raw material for coating desiccants such as paints and inks, PVC heat stabilizers, and lubricants and plasticizers. In addition, the ester compound produced by reacting the 2-ethylhexanoic acid with an alcohol may be used as a plasticizer.

In general, ester compounds are obtained by separately purchasing alcohols and carboxylic acids from which the compounds can be prepared and reacting them, or by producing carboxylic acids on their own and reacting them with alcohols. However, even in this case, a process for producing a carboxylic acid and a process for preparing an ester compound should be provided separately.

A conventional general method is described with reference to FIG. 1 as follows. First, the appropriate aldehyde 10 and oxygen 11 are injected together into the reactor 100 for reaction, and then the reaction product 12 is passed through the low boiling point impurity removing column 110 and the high boiling point impurity removing column 120, respectively. The carboxylic acid 20 is obtained. The carboxylic acid 20 was added to the esterification reactor 200 together with the alcohol 21 to react with an ester compound, followed by several stages of purification columns 210, 220, 230, and 240, followed by ester of desired purity. Compound (31) is obtained.

Therefore, in the conventional manufacturing method as described above, an independent reaction apparatus and an independent purification process were required to prepare the carboxylic acid and its ester compound, and because of the high equipment cost and operating cost, and due to mutual interference of process variables, This inconvenience and difficult management was a disadvantage.

In 1994, Romania Patent No. 108,680 discloses 2-ethylhexanol and 2-ethylhexanoic acid in a molar ratio of 1: 1 to 1: 5, temperature of 120 ° C. to 170 ° C., and reaction time of 1% to 10 hours. It was disclosed that a yield of 95% to 98% was achieved through esterification with 10% sulfuric acid catalyst. However, this method also has a configuration in which carboxylic acid is supplied from the outside, so that carboxylic acid cannot be obtained as a product. In addition, the use of a water-soluble sulfuric acid catalyst, which is a strong acid, was not easy for industrial application due to the problem of corrosion of the reactor material and a large amount of waste water through the water, neutralization and washing process in the sulfuric acid catalyst.

Therefore, there is a high demand for a production method capable of simultaneously obtaining a carboxylic acid and its ester compound in a simple process, but there is no known method for such a production method.

The technical problem to be achieved by the present invention is to provide a method for producing a carboxylic acid and an ester compound at the same time quick, simple and more economical.

The present invention provides a method for combining carboxylic acid and ester compound comprising the step of oxidizing the primary aldehyde compound in the presence of an oxidizing agent and alcohol in order to achieve the above technical problem.

The number of moles of the alcohol is preferably 5% to 200% based on the number of moles of the aldehyde compound. Moreover, it is preferable that carbon number of the said alcohol is 1-10.

In addition, the oxidant is preferably oxygen.

In addition, the reaction is preferably carried out at a pressure of 1 to 10 atm at a temperature of 10 ℃ to 100 ℃.

It is preferable that the reaction product is further introduced into a distillation column, and further comprising the step of obtaining a carboxylic acid and an ester compound at the bottom by reaction distillation.

The number of stages or theoretical stages of the distillation column is preferably 3 to 30 stages.

The inlet temperature of the distillation column is preferably from 5 ° C to 150 ° C and the pressure is from 0.2 bar to 2 bar.

It is preferable that the temperature of the top of the said distillation column is 80 degreeC-120 degreeC, and it is preferable that the temperature of a tower bottom is 125 degreeC-240 degreeC. In addition, the absolute pressure of the column top and the column bottom is preferably 0.1 bar to 1.1 bar.

Hereinafter, the present invention will be described in more detail.

The present invention provides a process for the co-oxidation of carboxylic acid and ester compounds comprising the step of oxidizing a primary aldehyde compound in the presence of an oxidizing agent and an alcohol. That is, the present invention relates to a method of co-acidifying a carboxylic acid and an ester compound by oxidizing a primary aldehyde compound in the presence of an oxidizing agent and an alcohol.

In the reactor, the primary aldehyde compound is oxidized by an oxidizing agent to produce carboxylic acid, in which the alcohol compound catalyzes. The carboxylic acid produced in the oxidation reaction reacts with alcohol to produce an ester compound.

The primary aldehyde compound is an aldehyde compound having 1 to 20 carbon atoms, and the carbon to which the aldehyde functional group (-CHO) is attached does not have any other carbon (formaldehyde) or only one is attached, and is not particularly limited. Examples of such primary aldehyde compounds include formaldehyde, acetaldehyde, propionaldehyde, normal butyraldehyde, isobutyraldehyde, pentanal, hexanal, 2-ethylhexanal, normaloctanal, nonanal, and 2-propyl. Heptane or the like, but is not limited thereto.

The oxidant may be a substance which is itself reduced while oxidizing, and examples thereof include oxygen, but are not limited thereto. Pure oxygen may be used as the oxidant, or a mixed gas of oxygen and an inert gas may be used.

The alcohol is preferably an alcohol having 1 to 10 carbon atoms. The alcohol also acts as a solvent, but acts as a reaction catalyst to increase the selectivity of the oxidation reaction in the oxidation reaction of aldehyde by oxygen. The alcohol also functions to prevent sudden temperature changes.

The alcohol content may be 5% to 200% based on the number of moles of the primary aldehyde compound, preferably 10% to 80%. When the content of alcohol is less than 5% of the number of moles of the primary aldehyde compound, the action of promoting the oxidation reaction of the primary aldehyde compound is weak and its role as a solvent is insufficient. In addition, when the content of alcohol exceeds 200% of the number of moles of the primary aldehyde compound, the concentration of the reactant is too low, the reaction rate is slowed down and the energy required to raise the temperature of the reactant is uneconomical.

It is preferable that it is 10 degreeC-100 degreeC, and, as for the temperature of the said reaction, it is more preferable that it is 20 degreeC-80 degreeC. If the reaction temperature is less than 10 ℃ there is a disadvantage that the conversion rate is lowered, if the reaction temperature exceeds 100 ℃ oxygen does not dissolve well in the solution has a disadvantage that the reaction rate is slow and conversion and selectivity is low.

The pressure of the reaction is preferably from 1 atmosphere to 10 atmospheres, more preferably from 1 atmosphere to 8 atmospheres. If the reaction pressure is less than 1 atm, there is a disadvantage in that the carboxylic acid in the product is not sufficiently produced, if the reaction pressure exceeds 8 atm, the effect of improving the reaction production rate is saturated and uneconomical.

The reaction is preferably carried out for 1 to 10 hours, more preferably for 2 to 8 hours. If the reaction time is less than 1 hour, the reaction is insufficient to obtain a sufficient product. If the reaction time is more than 10 hours, the reaction is almost completed and the reaction is not proceeded further.

The reactor may be a batch reactor, may be a semi-batch reactor, or may be a continuous reactor. In particular, the continuous reactor may be a continuous stirred tank reactor (CSTR).

If the reactor is a batch reactor, the reactants are added at the same time as mentioned above, the inlet is sealed and reacted with stirring, and if the reactor is a continuous reactor, the reactants are introduced into the reactor as described above. The reaction is carried out continuously while feeding at a rate of flow rate.

In the result of the reaction, almost all of the primary aldehyde compound supplied as a raw material is converted into carboxylic acid, but the alcohol supplied as the raw material serves only as a catalyst and consumes little by the reaction. That is, the condensation reaction to the ester compound does not occur much because the temperature of the reactants is low, and therefore the content of water and ester compound is not so high. Therefore, in order to obtain an ester compound sufficiently, the reaction product must be continuously reacted under appropriate reaction conditions.

In order for the carboxylic acid and the alcohol compound to react to form an ester compound, not only a reaction temperature higher than the temperature in the reactor is required but also water must be effectively removed from the system to reduce the reaction rate due to the proximity of the reaction equilibrium. It can be prevented and a large amount of ester compound can be obtained in a short time.

Water is removed from the product and reacted using reactive distillation to cause further reactions.

Reaction distillation refers to a unit operation for increasing the conversion rate and yield of a reactant by simultaneously discharging the reaction product out of the system by distillation in a reversible reaction. In other words, the reaction product is removed through the distillation column at the same time as the reaction to prevent the reaction equilibrium is reached, thereby allowing the reactant to continue to convert to the product.

This reaction distillation method is mainly used for reactions in which a reversible reaction occurs. These reactions include esterification reactions in which an ester compound and water are produced by reaction of an acid and an alcohol compound, an acetal compound and an alcohol compound by reaction of an aldehyde compound and an alcohol compound. It can be used for the acetal reaction in which water is produced, and the reaction in which the sodium salt of the amine compound and the organic acid is formed by the reaction of the salt of amine, organic acid and sodium hydroxide (NaOH).

The reaction mixture in the reactor is introduced into a distillation column to cause this reactive distillation. The reaction mixture may be placed in the distillation column in gaseous form or in the distillation column in liquid form.

The distillation column may be a conventional distillation column commonly used in the distillation process. As a device for causing gas-liquid equilibrium, a tray may be provided inside, a packing may be provided, or both the tray and the packing may be provided. The tray may be a bubble cap tray, a valve tray, a sieve tray, or the like, but is not limited thereto. The packing may be random packing, structured packing or more preferably structured packing, but is not limited thereto.

The number of stages or theoretical stages of the tray or packing is preferably 3 to 30 stages. When the number of stages or theoretical stages is smaller than three stages, gas-liquid equilibrium is not well formed, and the separation and reaction of materials do not occur sufficiently. When the number of stages or theoretical stages is more than 30 stages, the size of the column is Larger than necessary, uneconomical.

The reaction mixture of the reactor may be introduced into the side of the distillation column, or may be introduced near the bottom of the distillation column.

The inlet temperature of the distillation column is preferably from 5 ° C to 150 ° C and the pressure is from 0.2 bar to 2 bar. If the inlet temperature of the column is less than 5 ° C., the reaction rate is too slow and the separation is difficult to occur. If the inlet temperature of the column exceeds 150 ° C., temperature reversal in the column may occur, which is not preferable. In addition, if the inlet pressure of the column is less than 0.2 bar, the temperature of the column bottom may be lowered, and the reaction rate may be slowed. If the inlet pressure of the column exceeds 2 bar, the temperature of the top of the column may be increased. Possible steam supply becomes difficult and the cost of the device rises.

The reaction mixture introduced into the distillation column moves some of the unreacted carboxylic acid and water to the top by gas-liquid equilibrium, and the ester compound, the product, to the bottom. The alcohol also moves to the bottom because the boiling point is high due to hydrogen bonding.

The gas collected at the top of the distillation column is condensed by cooling in a condenser as a mixture of water vapor and unreacted carboxylic acid and then separated by phase separation in an oil / water separator. In other words, since the condensed water and the unreacted carboxylic acid in the oil / water separator are separated into two phases, the water layer is discharged to the outside, and the unreacted carboxylic acid is refluxed to the column top. At this time, a part of the unreacted carboxylic acid may be discharged to the outside of the system in consideration of the material resin and the energy resin.

The temperature of the column top is preferably 80 ° C to 120 ° C, and the absolute pressure of the column top is preferably 0.1 bar to 1.1 bar. If the temperature of the tower top is less than 80 ° C., there is a fear that the water drops to the bottom. If the temperature of the tower top exceeds 120 ° C., the temperature is unnecessarily high and uneconomical. If the absolute pressure of the column top is less than 0.1 bar, the equipment cost is high. If the absolute pressure of the column top exceeds 1.1 bar, the investment cost and equipment cost are high as the pressure resistant design is required.

On the other hand, there is a carboxylic acid produced in the reactor at the bottom of the distillation column, including the bottom, the carboxylic acid and the alcohol reacts to produce the ester compound and water. In the distillation column, water is transferred to and removed from the column by distillation, so that the reactants of the reaction do not approach the reaction equilibrium and are quickly converted to the product by this thermodynamic effect.

For example, a Lewis acid catalyst such as tetra isopropyl titanate, tetra normal butyl titanate, or tetra 2-ethylhexyl titanate may be used for the reaction, that is, a reaction in which an alcohol and a carboxylic acid react to form an ester compound. It may be reacted without a Lewis acid catalyst as described above. As such, when the reaction is performed without a catalyst, a process of separating the catalyst later is unnecessary.

A reboiler may be further included at the bottom of the distillation column. The reboiler serves to supply energy for distillation to the distillation column by heating the reaction mixture at the bottom of the column.

It is preferable that the temperature of a column bottom is 125 degreeC-240 degreeC, and it is preferable that the absolute pressure of a column bottom is 0.1 bar-1.1 bar. If the temperature of the bottom of the column is lower than 125 ° C., the temperature of the entire column may be low and reaction and separation may be inefficiently performed. If the temperature of the column exceeds 240 ° C., the alcohol and ester compounds of the column may rise to the top of the column. It is not desirable. If the bottom pressure is less than 0.1 bar, the equipment cost is high, and if the top pressure is more than 1.1 bar, the investment pressure and equipment cost are high as the pressure resistant design is required.

Through this process, a mixture of carboxylic acid and ester compound is present at the bottom. Thus, in order to separate the carboxylic acid and the ester compound, a separate separation technique such as distillation can be used for the bottom product.

It is preferable that the selectivity of the primary aldehyde compound converted to the carboxylic acid and the ester compound according to the preparation method of the present invention is 93% to 99%. When the selectivity is lower than 93%, the amount of the carboxylic acid and ester compound obtained is small compared to the amount of the primary aldehyde compound to be added, which is economically disadvantageous. It is very difficult to produce the selectivity higher than 99%.

The selectivity may be calculated by the following Equation 1.

[Equation 1]

Selectivity (%) = (produced carboxylic acid and ester compound in moles) / (reacted primary aldehyde compound in moles) × 100.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the manufacturing method. However, this is illustrative and does not limit the scope of the present invention.

As shown in FIG. 2, the primary aldehyde compound 40, the oxidizing agent 42, and the alcohol 41 are introduced into the reactor 300. The reactor 300 may be a CSTR as shown in FIG. 2. The unreacted primary aldehyde compound 40, the alcohol, and the resulting carboxylic acid which have been reacted in the reactor 300 are fed to a distillation column 350 for reactive distillation (43).

High boiling ester compounds and alcohols descend with the carboxylic acid down the distillation column, and water and some carboxylic acids are evaporated to the top. This is by azeotropic distillation.

The water vapor and carboxylic acid gathered in the column top can be condensed in a condenser and then separated through phase separation in an oil / water separator. Water is discharged to the outside of the system to remove it, and the carboxylic acid is refluxed to the column top in consideration of the material resin and the energy resin. When the amount of the carboxylic acid is greater than the amount required for reflux to the column top, it may be circulated to the reactor or discharged to the outside of the system.

On the other hand, the alcohol descends to the bottom and continuously reacts with the unreacted carboxylic acid to form ester compounds with water. At this time, since the water has a relatively low boiling point, it evaporates rapidly and moves to the top of the column, thereby removing access to the reaction equilibrium, thereby maintaining the speed of the reaction rapidly.

On the way down to the bottom, all unreacted alcohol reacts and is converted into an ester compound. The tower bottom uses a reboiler to supply energy for the operation of the distillation column 350.

The carboxylic acid and ester compounds can be obtained using the bottom product 45, for example by separating them using separation techniques such as distillation. The separation method uses four separation devices as shown in FIG.

First, a material having a lower boiling point than the ester compound and the carboxylic acid is removed through the first low boiling point removal column 400 (46). The carboxylic acid is then separated off the column via carboxylic acid cut column 410 (48). Only the ester compound and impurities remain in the bottom product 49 of the carboxylic acid cut column 410. Therefore, the bottom product 49 of the carboxylic acid cut column 410 is placed in the second low boiling point removal column 420 to remove low boiling impurities (50), and the ester compound (52) through the ester compound distillation column (430). ) Will be produced.

Therefore, according to one embodiment of the present invention shown in FIG. 2, it is possible to simultaneously produce the carboxylic acid 46 and the ester compound 52.

In the above embodiment, the distillation columns 400, 410, 420, and 430 for separation may be reversed with each other in some cases, and may be separated using other methods than distillation, but are not limited thereto.

Hereinafter, the structure and effects of the present invention will be described in more detail with specific examples and comparative examples, but these examples are only intended to more clearly understand the present invention and are not intended to limit the scope of the present invention.

<Example 1>

110 g of 2-ethylhexanal and 55 g of 2-ethylhexanol were added to a 500 mL stainless steel 316 high-pressure reactor. When nitrogen was sufficiently flown to adjust the temperature of the reactor to 25 ° C, oxygen was released. The reaction was carried out by stirring while slowly injecting at 100 mL / min. As the reaction progressed, the pressure inside the reactor gradually increased. After about 6 hours, the internal pressure of the reactor became 8 bar and the reaction was terminated.

<Example 2>

300 g of 2-ethylhexanal and 50 g of 2-ethylhexanol were added to a 1000 mL glass reactor, and the reaction was performed while slowly injecting oxygen at 180 mL / min per minute while maintaining the reactor temperature at 25 ° C. As the reaction progressed, the pressure inside the reactor gradually increased. The reaction was terminated when the internal pressure of the reactor reached 6 bar.

<Example 3>

300 g of 2-ethylhexanal and 225 g of isobutanol were added to a 1000 mL glass reactor, and the reaction was performed by slowly injecting oxygen at a flow rate of 180 mL / min per minute while maintaining the reactor temperature at 25 ° C. As the reaction progressed, the pressure inside the reactor gradually increased. The reaction was terminated when the internal pressure of the reactor reached 6 bar.

<Example 4>

110 g of 2-ethylhexanal and 55 g of 2-ethylhexanol were added to a 500 mL stainless steel 316 high-pressure reactor. When nitrogen was sufficiently flown to adjust the temperature of the reactor to 25 ° C, oxygen was released. The reaction was carried out by stirring while slowly injecting at 100 mL / min. As the reaction progressed, the pressure inside the reactor gradually increased. After 3 hours had elapsed, the reaction temperature was raised to 80 ° C. When the total reaction time was about 6 hours, the internal pressure of the reactor became 8 bar and the reaction was terminated.

Example 5

55 g of 2-ethylhexanal and 110 g of 2-ethylhexanol were added to a 500 mL stainless steel 316 high-pressure reactor. When nitrogen gas was flowed sufficiently to adjust the temperature of the reactor to 25 ° C, oxygen was released. The reaction was carried out by stirring while slowly injecting at 100 mL / min. As the reaction progressed, the pressure inside the reactor gradually increased. After about 6 hours, the internal pressure of the reactor became 8 bar and the reaction was terminated.

Comparative Example 1

Into a 500 mL stainless steel 316 high pressure reactor, 165 g of 2-ethylhexanal was added with enough nitrogen to give a pressure of 4 bar and the reactor temperature was adjusted to 25 ° C. The reaction was carried out by stirring. As the reaction progressed, the pressure inside the reactor gradually increased. After about 5 hours, the internal pressure of the reactor became 8 bar and the reaction was terminated.

Comparative Example 2

Put 160 g of 2-ethylhexanal into 500 mL of stainless steel 316 high pressure reactor, and when nitrogen flows to 4 bar, set the temperature of the reactor to 25 ° C and slowly inject oxygen at 100 mL / min. The reaction was carried out by stirring. As the reaction progressed, the pressure inside the reactor gradually increased. After 4 hours, the reaction temperature was raised to 60 ° C. When the total reaction time was about 6 hours, the internal pressure of the reactor became 6 bar and the reaction was terminated.

Comparative Example 3

300 g of 2-ethylhexanal was added to a 1000 mL glass reactor, and the reaction was performed while slowly injecting oxygen at a flow rate of 180 mL / min per minute while maintaining the reactor temperature at 25 ° C. As the reaction progressed, the pressure inside the reactor gradually increased. The reaction was terminated when the internal pressure of the reactor reached 6 bar.

The reaction products of Examples 1 to 5 and Comparative Examples 1 to 3 were analyzed to obtain results as shown in Table 1 below.

TABLE 1

Reaction Product (%) % Conversion Selectivity (%) Aldehyde (g) Solvent (g) Alcohol Aldehyde Carboxylic acid Etc Example 1 2-ethylhexanal (110) 2-ethylhexanol (55) 32.50 1.06 62.10 4.34 98.4 93.2 Example 2 2-ethylhexanal (300) 2-ethylhexanol (50) 32.02 0.27 63.73 3.98 99.6 93.8 Example 3 2-ethylhexanal (300) Isobutanol (225) 40.18 1.15 55.37 3.30 98.1 93.9 Example 4 2-ethylhexanal (110) 2-ethylhexanol (55) 30.59 0.29 64.10 5.02 99.6 91.9 Example 5 2-ethylhexanal (55) 2-ethylhexanol (110) 64.40 4.15 30.71 0.74 88.3 97.7 Comparative Example 1 2-ethylhexanal (165) - 0.53 0.00 85.28 14.19 99.4 85.2 Comparative Example 2 2-ethylhexanal (160) - 0.51 14.30 72.33 12.86 85.7 84.4 Comparative Example 3 2-ethylhexanal (300) - 0.52 0.60 84.60 14.28 99.4 84.6

As can be seen in Table 1, in the case of Examples 1 to 5 reacted with alcohol, it can be seen that the conversion and the selectivity are very excellent. However, in the case of Comparative Examples 1 to 3 in which only aldehyde was reacted, it was found that the conversion rate was insufficient or the selectivity was inferior.

<Example 6>

The experiment was conducted using a 1000 mL glass reactor equipped with a reaction temperature control system and a distillation column with a diameter of 3 cm and a height of 21 cm at the top of the reactor. The distillation column was packed with 4 mm diameter and 4 mm high Rashik ring type packings. 156.3 g of 2-ethylhexanol and 422.9 g of isobutyric acid were added to the reactor, and the reaction was performed for 3 hours while heating the reaction temperature to 230 ° C.

<Example 7>

The reaction was carried out in the same manner as in Example 6, except that the reaction time was 6 hours.

<Comparative Example 4>

Experiments were performed by attaching only Dean-Stark apparatus to a 1000 mL glass reactor equipped with a reaction temperature control system but without a distillation column. 156.3 g of 2-ethylhexanol and 422.9 g of isobutyric acid were added to the reactor, and the reaction was performed for 6 hours while heating the reaction temperature to 230 ° C.

The reaction products of Examples 6 and 7, Comparative Example 4 were analyzed and the results are shown in Table 2 below.

TABLE 2

Example 6 Example 7 Comparative Example 4 Alcohol conversion rate (%) 95.8 99.3 90.5 Ester Yield (%) 95.8 99.3 90.5 Reaction product composition (%) Alcohol 1.99 0.36 4.08 Carboxylic acid 51.13 51.63 52.79 ester 46.88 48.01 17.83 Other 0.00 0.00 25.3

As can be seen in Table 2, in Examples 6 and 7 subjected to reactive distillation, the carboxylic acid was converted into an ester compound by reacting with alcohol without producing byproducts, whereas Comparative Example 4 was not subjected to reactive distillation. It can be seen that in some cases ester compounds have been produced but a significant amount of by-products occur together.

Although described in detail with respect to preferred embodiments of the present invention as described above, those of ordinary skill in the art, without departing from the spirit and scope of the invention as defined in the appended claims Various modifications may be made to the invention. Therefore, changes in the future embodiments of the present invention will not be able to escape the technology of the present invention.

The combined method of the carboxylic acid and the ester compound of the present invention enables not only to prepare the carboxylic acid and the ester compound in a single process but also to increase the yield and selectivity of the ester compound by using alcohol as a catalyst and a reactant. Therefore, there is an effect that allows the production of carboxylic acid and ester compounds quickly, simply and more economically.

Claims (16)

A method of co-addition of carboxylic acid and ester compound comprising the step of oxidizing the primary aldehyde compound in the presence of an oxidizing agent and alcohol. The method according to claim 1, wherein the aldehyde compound has 1 to 20 carbon atoms. The method according to claim 1, wherein the oxidant is oxygen. The method according to claim 1, wherein the alcohol has 1 to 10 carbon atoms. The method according to claim 1, wherein the molar number of the alcohol is 5% to 200% based on the mole number of the primary aldehyde compound. The method of claim 1, wherein the reaction is carried out at a temperature of 10 ℃ to 100 ℃ and a pressure of 1 to 10 atm. The method according to claim 1, wherein the reaction is carried out for 1 to 10 hours. The carboxylic acid and ester according to claim 1, further comprising introducing the oxidized reactant into a distillation column and obtaining carboxylic acid and ester compounds at the bottom by reactive distillation. Combined method of compound. The method according to claim 8, wherein the inlet temperature of the distillation column is 5 ° C to 150 ° C and the pressure is 0.2 bar to 2 bar. 9. The process according to claim 8, wherein the distillation column has a tray or packing therein. The method according to claim 8, wherein the number of stages or theoretical numbers of the distillation column is from 3 to 30 stages. The method according to claim 8, wherein the temperature of the column top of the distillation column is 80 ° C to 120 ° C and the pressure of the column top is 0.1 bar to 1.1 bar. The method according to claim 8, wherein the temperature of the bottom of the distillation column is 125 ° C to 240 ° C, and the pressure of the column bottom is 0.1 bar to 1.1 bar. 10. The method according to claim 8, wherein water is removed from the distillate of the top of the distillation column and the remaining distillate is refluxed to the top of the distillation column. The method according to claim 1, wherein the selectivity of the reactants converted to carboxylic acid and ester compounds is 93% to 99%. The method according to claim 1, further comprising the step of separating the carboxylic acid and the ester compound from the product, respectively.

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