KR101293818B1 - METHOD FOR PREPARING α, β-UNSATURATED ALDEHYDE - Google Patents

Abstract

The present invention relates to a method for producing α, β-unsaturated aldehydes in which the production of C9-aldehyde is maximized. More specifically, n-butanal and C5-aldehyde (linear and branched aldehyde mixture having 5 carbon atoms) are 1: Aldol-condensation of C9-aldehyde, characterized in that the Aldol-condensation reaction at 60 to 130 ℃ under a base catalyst at a weight ratio of 1 to 5: 1 (n-butanal: C5-aldehyde) It relates to a manufacturing method.
According to the present invention, there is an effect of providing a method for preparing α, β-unsaturated aldehyde including a mixed aldolic reaction to maximize the production of C9-aldehyde by controlling the type and ratio of mixed aldehydes as starting materials. .

Description

METHOD FOR PREPARING α, β-UNSATURATED ALDEHYDE}

The present invention relates to a method for producing α, β-unsaturated aldehydes in which the production of C9-aldehyde is maximized, and more specifically, to control the type and ratio of mixed aldehydes, which are starting materials, to control the production of C9-aldehyde. It relates to a method for producing α, β-unsaturated aldehyde including a maximized hybrid aldol reaction.

The aldol-condensation reaction is a general reaction of aldehydes with α-hydrogen atoms under a base catalyst, which produces α, β-unsaturated aldehydes with greatly increased carbon number.

The aldol-condensation reaction is generally divided into two aldehyde reacting symmetrical aldol-condensation reaction and two aldehyde mixed aldol-condensation reaction, the symmetric aldol-condensation reaction is one kind A product is obtained, but the hybrid aldol-condensation reaction yields four or more products.

For example, when a mixture of acetaldehyde and propanal is reacted under a base catalyst, a problem arises in that a complex mixture containing two symmetric aldol products and two hybrid aldol products is produced.

US Pat. No. 6,482,972 discloses a hybrid aldol-condensation reaction of n-butanal and pentanal, but C10-aldehyde is obtained as a main product, and Korean Patent Publication No. 2001-0080555 discloses a basic alkali metal compound. A method of producing unsaturated aldehyde by an aldol-condensation reaction by contact with a granular catalyst comprising a cellulose is disclosed, but it does not mention a method of obtaining a hybrid aldol product in high yield or producing C9-aldehyde.

In order to solve the problems of the prior art as described above, the present invention is to adjust the type and ratio of the mixed aldehydes (starting material) and the ratio of α, β-unsaturated aldehyde including a hybrid aldol reaction to maximize the production of C9-aldehyde An object of the present invention is to provide a manufacturing method.

The above and other objects of the present invention can be achieved by the present invention described below.

In order to achieve the above object, the present invention provides a weight ratio (n-butanal: C5-aldehyde) of n-butanal and C5-aldehyde (linear and branched aldehyde mixture having 5 carbon atoms) of 1: 1 to 5: 1. It provides a method for producing α, β-unsaturated aldehyde maximized the production of C9-aldehyde, characterized in that the Aldol-condensation reaction at 60 to 130 ℃ under a base catalyst.

As described above, according to the present invention, a method for preparing α and β-unsaturated aldehydes including hybrid aldehyde reactions in which the production of mixed aldehydes, which are starting materials, and the ratio thereof are maximized to maximize the production of C9-aldehydes. It is effective to provide.

Hereinafter, the present invention will be described in detail.

In the method for producing α, β-unsaturated aldehyde in which the production of C9-aldehyde of the present invention is maximized, the weight ratio of n-butanal and C5-aldehyde (a linear and branched aldehyde mixture having 5 carbon atoms) of 1: 1 to 5: 1 (n-butanal: C5-aldehyde) is characterized in that the aldol-condensation reaction at 60 to 130 ℃ under a base catalyst.

The weight ratio of n-butanal and C5-aldehyde may be more preferably 2: 1 to 4: 1. Within this range, the production of C8- and C10-aldehydes is suppressed and the production of C10-aldehydes is maximized. It works.

The C5-aldehyde is preferably composed of n-pentanal, 2-methyl butyraldehyde and 3-methyl butyraldehyde.

The n-pentanal is 25 to 45 wt%, 2-methyl butyraldehyde is 25 to 45 wt%, and 3-methyl butyraldehyde is preferably 20 to 40 wt%.

The base catalyst may be an alkali metal carbonate, an alkali metal hydroxide or an amine, preferably an alkali metal hydroxide, and more preferably NaOH or KOH.

The base catalyst is preferably included in the range of 0.01 to 0.1 mol based on a total of 1 mole of n-butanal and C5-aldehyde, the rate of aldol reaction is fast within this range, the amount of unreacted aldehyde is small, C12 or more heavy It has the effect of lowering the production of heavy substances.

The solvent of the aldol-condensation reaction is an aqueous solution or alcohol containing a base catalyst, and preferably an aqueous solution in which the base catalyst is dissolved. In this case, an organic product is easily separated by a density difference.

The solvent is preferably used in a weight ratio of 1: 0.5 to 1: 3 based on the total weight of n-butanal and C5-aldehyde. If the solvent is less than 0.5, the reaction does not occur well. Relatively small, there is a problem that the amount of product decreases with the reaction time.

The aldol-condensation reaction is more preferably carried out at 60 to 130 ℃, if the reaction is less than 60 ℃ within this range there is a problem that the amount of the base catalyst to increase a lot, if it exceeds 130 ℃ C12 There is a problem that the production amount of the above heavy components is increased.

The pressure of the aldol-condensation reaction is not particularly limited when it is equal to or more than the vapor pressure at the reaction temperature of the reactant n-butanal, but may be performed at 1 to 10 barg, and preferably at 2 to 4 barg.

The aldol-condensation reaction may be carried out for 0.2 (12 minutes) to 2 hours. If the reaction time is short, unreacted aldehydes remain, and if the reaction time is long, the amount of heavy component of C12 or more is increased. there is a problem.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the present invention. Such variations and modifications are intended to be within the scope of the appended claims.

[Example]

Example 1

The experiment was conducted using a 1L Pyrex Jacket reactor. The reaction temperature was controlled using a circulator, and the reaction was stirred using a mechanical stirrer. During the reaction, nitrogen was continuously purged to block contact with air, and the reaction proceeded at normal pressure, and a condenser was mounted to reflux the aldehyde component flowing out into the gas phase. This aldol condensation reaction proceeded using NaOH as a catalyst. NaOH was first fed into the reactor in aqueous solution at a concentration of 2% by weight. 200 g of reactant n-butanal and 200 g of C5-aldehyde (a mixture consisting of 35% by weight of n-pentanal, 35% by weight of 2-methyl butyraldehyde, and 30% by weight of 3-methyl butyraldehyde) were added. After raising to 70 ° C., the solution was poured into the upper portion of NaOH aqueous solution. The reaction time was reacted at 70 ° C. for 1 hour, and then the reaction temperature was raised to 90 ° C., followed by another reaction for 1 hour. After completion of the reaction, the product was separated from NaOH aqueous solution and analyzed by gas chromatography (GC) for its composition.

Example 2

266.7 g of n-butanal as a reactant in Example 1 was used, and C5-aldehyde (a mixture consisting of 35% by weight of n-pentanal, 35% by weight of 2-methyl butyraldehyde, and 30% by weight of 3-methyl butyraldehyde) was used. It carried out in the same manner as in Example 1, except that 133.3 g (weight ratio 2: 1) was used.

Example 3

In Example 1, 300.0 g of n-butanal as a reactant was used, and C5-aldehyde (a mixture consisting of 35% by weight of n-pentanal, 35% by weight of 2-methyl butyraldehyde, and 30% by weight of 3-methyl butyraldehyde) was used. The same procedure as in Example 1 was carried out except that 100.0 g (weight ratio 3: 1) was used.

Example 4

In Example 1, 320.0 g of n-butanal as a reactant was used, and C5-aldehyde (a mixture consisting of 35% by weight of n-pentanal, 35% by weight of 2-methyl butyraldehyde, and 30% by weight of 3-methyl butyraldehyde) was used. The same procedure as in Example 1 was carried out except that 80.0 g (weight ratio 4: 1) was used.

Comparative Example 1

133.3 g of n-butanal as a reactant in Example 1 was used, and C5-aldehyde (a mixture consisting of 35% by weight of n-pentanal, 35% by weight of 2-methyl butyraldehyde, and 30% by weight of 3-methyl butyraldehyde) was used. The same procedure as in Example 1 was carried out except that 266.7 g (weight ratio 0.5: 1) was used.

Comparative Example 2

342.9 g of n-butanal as a reactant in Example 1 was used, and C5-aldehyde (a mixture consisting of 35% by weight of n-pentanal, 35% by weight of 2-methyl butyraldehyde, and 30% by weight of 3-methyl butyraldehyde) was used. The same procedure as in Example 1 was carried out except that 57.1 g (weight ratio 6: 1) was used.

[Test Example]

The composition and content of the α, β-unsaturated aldehydes prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were measured and analyzed by gas chromatography (Hewlett-Packard company model 5890GC, column HP-1). Is shown in Table 1 below

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 product C8-aldehyde (% by weight) 40.3 50.0 55.0 64.5 32.2 74.3 C9-aldehyde 23.1 28.1 34.5 27.3 6.6 19.0 C10-aldehyde 20.5 10.4 1.5 1.2 40.1 1.5 Unreacted C5-aldehyde 12.1 8.0 6.0 4.8 16.1 3.2 C-12 or higher components 4.0 3.5 3.0 2.2 5.0 2.0

As shown in Table 1, the α, β-unsaturated aldehyde mixture (Examples 1 to 4) prepared by the method for preparing α, β-unsaturated aldehyde of the present invention contains 23 wt% or more of C9-aldehyde as a main product. However, when the weight ratio of n-butanal and C5-aldehyde mixture is 0.5: 1 (Comparative Example 1) and 6: 1 (Comparative Example 2), the prepared α, β-unsaturated aldehyde mixture is composed of C9 as a main product. It was confirmed that the excessive amount of C8-aldehyde or C10-aldehyde that is not.

Claims (7)

Aldol-condensation of n-butanal and C5-aldehyde (a mixture of linear and branched pentanal) at 60-130 ° C. under a base catalyst in a weight ratio (n-butanal: C5-aldehyde) of 1: 1 to 5: 1. Reaction to give C9-aldehyde as the main product,
Here, the C5-aldehyde is 25 to 45% by weight of n-pentanal, 25 to 45% by weight of 2-methyl butyraldehyde, and 20 to 3-methyl butyraldehyde. Characterized in that 40 wt%
A process for producing an alpha, beta-unsaturated aldehyde.
The method of claim 1,
The weight ratio of n-butanal and C5-aldehyde is characterized in that 2: 1 to 4: 1
Method for producing α, β-unsaturated aldehyde. The method of claim 1,
The base catalyst is characterized in that the alkali metal carbonate, alkali metal hydroxide or amine
Method for producing α, β-unsaturated aldehyde. The method of claim 1,
The base catalyst is characterized in that 0.01 to 0.1 mole based on 1 mole of n-butanal and a total of C5-aldehyde.
Method for producing α, β-unsaturated aldehyde. The method of claim 1,
The aldol-condensation reaction is carried out using water as a solvent in a weight ratio of 1: 0.5 to 1: 3 based on the total weight of n-butanal and C5-aldehyde.
Method for producing α, β-unsaturated aldehyde. delete delete