JPH04112846A - Production of aldehyde - Google Patents

Abstract

PURPOSE:To advantageously obtain an aldehyde of high quality by efficiently and simply separating a specific aliphatic alcohol and the aforementioned aldehyde prepared from the alcohol according to dehydrogenation thereof with pseudo-moving beds using a specific adsorbent without requiring heating at high temperatures. CONSTITUTION:Both (A) an average 10-30C straight-chain/branched chain saturated/ unsaturated aliphatic alcohol and (B) an aliphatic aldehyde obtained by dehydrogenating the alcohol (A) are separated from a raw material mixture containing both to produce the aliphatic aldehyde (B). In the process, packed columns (C1) to (C12) filled with silica gel are connected in series in a liquid passage in an endless form and eluate feed ports (a), taking outlets (b) for the solution (A), raw material mixture solution feed ports (c) and taking outlets (d) for the purified liquid (B) are arranged in the above-mentioned order along the flow of the solution at a prescribed interval. Pseudo-moving beds intermittently and successively moving the ports (a) to (d) to the downstream side are used as an adsorber to bring the adsorbent into apparent countercurrent contact with the eluate and enable continuous operation. Thereby, treating efficiency is remarkably raised and the amounts of the adsorbent and the eluate are simultaneously reduced to advantageously afford the aldehyde (B) of high quality.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application 1] The present invention relates to a method for producing aliphatic aldehydes useful as fragrances or organic synthesis intermediates. In particular, the present invention relates to a method for producing aliphatic aldehydes that can be easily and efficiently purified to high purity without causing denaturation of aldehydes during purification.

[Prior Art] Aldehydes are useful as intermediates for organic synthesis, and several methods have been proposed for producing them.

Conventionally, the method commonly used is Rosenmund reduction of carboxylic acid chloride, but it is not used as an industrial production method because the reduction catalyst is easily poisoned and the treatment of hydrochloric acid as a by-product is a problem. That's difficult.

Therefore, a method using dehydrogenation of alcohol has been proposed. In the method of dehydrogenating alcohol, the conversion rate in the reaction is not high, so it is necessary to separate the aldehyde and unreacted alcohol after the reaction.

In the separation of aldehydes and alcohols, distillation is usually used, or when the number of carbon atoms in the alcohol and aldehyde is large, or when the aldehyde and alcohol are each a mixture of compounds with various carbon numbers, it is difficult to use distillation for the following reasons. It is very difficult to apply. If the number of carbon atoms is large, the viscosity will be high and the fluidity will be poor, so in order to perform distillation efficiently, it is necessary to increase the fluidity by heating to a high temperature and to reduce the pressure. These operations require large equipment costs and consume a large amount of energy, and when handling components with poor thermal stability,
This causes thermal denaturation of the aldehydes, leading to a decline in the quality of the produced aldehydes.

In addition, if it is a mixture of aldehydes and alcohols or compounds with various carbon numbers, the boiling points of aldehydes and alcohols with different carbon numbers often overlap, and in that case it is impossible to separate them by distillation. In addition to distillation methods, adsorption methods are also used, such as batch adsorption methods in which an adsorbent such as Norkaker is simply mixed and stirred with the raw material, or column chromatography using a single packed column packed with an adsorbent. The usage fees for the adsorbent and eluent are enormous, which poses an economic problem.

In addition, a method for separating alcohol and aldehyde using a pseudo-moving bed using X-type theolite as an adsorbent was reported in Japanese Patent Publication No. 1
Although this method is disclosed in Japanese Patent No. 30811, it is still not sufficient in terms of separation efficiency.

[Problems to be Solved by the Invention] The present invention provides a method for obtaining extremely high-quality aliphatic aldehydes by efficiently and simply removing alcohol, which is an impurity, without requiring high-temperature heating.

[Means for Solving the Problems] In order to solve the above problems, the inventors of the present invention have conducted intensive studies to separate aliphatic aldehydes and aliphatic alcohols using a pseudo-moving bed using a specific adsorbent. The inventors have discovered that the aliphatic aldehyde can be separated very efficiently and a high-quality aliphatic aldehyde can be obtained by doing so, and the present invention has been completed.

That is, the present invention is directed to linear or branched chains having an average carbon number of 10 to 3.
Saturated or unsaturated aliphatic alcohols having 0 (hereinafter referred to as
It's simply called alcohol. ) and aliphatic aldehyde (hereinafter simply referred to as aldehyde) obtained by dehydrogenating the alcohol. When producing aliphatic aldehyde by separating both from a raw material mixture, Silkakel was filled as an adsorption device. The packed towers are connected in series through a liquid passage, and the first packed tower and the last packed tower are also connected through a liquid passage to form an endless structure. A take-out port, a raw material mixture solution supply port, and an aldehyde purified liquid take-out port are arranged in this order at predetermined intervals along the flow direction of the solution, and at the same time the raw material mixture solution and eluent are supplied, the alcohol solution and the aldehyde purified liquid,
The present invention also provides a method for producing an aliphatic aldehyde, which is characterized in that a pseudo-moving bed is used by sequentially and intermittently moving these supply ports and take-out ports downstream.

In the present invention, a pseudo moving bed is used as an adsorption device. Using a pseudo-moving bed allows continuous operation by bringing the adsorbent and eluent into apparent countercurrent contact, dramatically improving processing efficiency and greatly reducing the amount of adsorbent and eluent used. I can do it.

The high-purity aldehyde obtained in the present invention is obtained by first synthesizing a mixture containing an aldehyde and an alcohol, and then purifying this mixture. The above mixture may be synthesized by a well-known method. That is, for example, a method of dehydrogenating alcohol in the presence of a catalyst may be used.

As the mixture containing aldehyde and alcohol according to the present invention, a raw material mixture containing an aliphatic alcohol having an average carbon number of 10 to 30 or less and an aldehyde obtained by dehydrogenating the alcohol is used. Preferably, the average number of carbon atoms is 12 to 20. Specific examples of alcohols include saturated If-chain aliphatic alcohols such as lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol, unsaturated straight-chain aliphatic alcohols such as oleyl alcohol, and saturated +o branched fatty alcohols such as instearyl alcohol. unsaturated branched aliphatic alcohols such as group alcohols and geraniol;
Not limited to these. Further, a mixture of these compounds having different numbers of carbon atoms, branch positions, etc., or a mixture of isomers may be used.

In the present invention, silica gel is used as an adsorbent.

Silica gel is a polar adsorbent that selectively adsorbs polar substances. Since alcohols and aldehydes have different polar groups, they have different adsorption properties on silica gel, and this difference can be used to separate the two. Specifically, M, S, GEL D-350-60A manufactured by Hansu Kagaku Kogyo Co., Ltd.
and D-350-120A1 Microbeads manufactured by Fuji Davison Chemical Co., Ltd./Rikakel MB-48 and ~IB-5D
Examples include, but are not limited to, the following:

The particle size of the adsorbent is not particularly limited, but in consideration of separation performance and operability, it is preferably 50 to 1000 μm, more preferably 100 to 800 μm. If the particle size is too small, the pressure drop within the packed column will increase, making operation difficult; if the particle size is too large, drifting will occur, reducing separation performance. Further, in order to prevent drifting, the particle size distribution is preferably small, and the particle shape is preferably spherical rather than irregularly crushed.

The pore size of the adsorbent is not particularly limited, or in consideration of separation performance, is preferably 30 to 300, more preferably 50 to 200. If the pore size is too small, the diffusion rate into the pores will decrease, resulting in a decrease in separation ability. In particular, if the molecular size of the substance to be separated is larger than the pore diameter, separation is impossible. If the pore size is too large, the amount of adsorption of the substance will be reduced. In addition, it is preferable that the pore size distribution is small, and as a polar adsorbent, activated alumina, silica gel pond, etc.
Considering the separability of aldehyde and alcohol, silica gel is the most suitable among these for the following reasons.

When performing adsorption operations, depending on the separation target,
It is necessary to select the most suitable adsorbent particle size, particle shape, pore size, pore volume, etc., but when separating aldehydes and alcohols, activated alumina and zeolite have a wide range of choices. Narrow and difficult to get the best one for separation. Activated alumina and zeolite are generally easily available as powders with a particle size of 100μl or less, or molded products with a particle size of 14x or more, and those in between.
Generally, particles with a particle size of In addition, activated alumina has a large distribution of pore diameters, which lowers the degree of separation, making it unsuitable.

Zeolite has the characteristic of having very uniform pore diameters, but the maximum pore diameter is approximately 10 pores, and it is difficult for substances with large molecular weights or substances with large steric exclusion to diffuse into the pores. Either this is not possible, or even if it is possible to diffuse into the pores, the diffusion rate within the pores is so low that separation is practically impossible. Against these, /Rikakel,
There are various particle sizes ranging from 50 to 1000 μm and pore sizes ranging from 10 to 300 μm, and their distribution is small and the particle shape is spherical, depending on the target substance to be separated. You can choose things.

In the present invention, the solvent used as the eluent is selected from a polarity suitable for each adsorbent, taking into consideration the adsorption properties of the aldehyde and alcohol to be separated. The solubility parameter is used as an indicator of the polarity of the solvent. Solubility parameters are C, M.

Hansen 7 (C, M, Hansen), J Paint Tech, 39.104 (19
67)). However, in the case of a mixture consisting of n components, calculation was performed using the following formula (2).

δ=Σ (φi・δi) (2) (In the formula, φi is the volume fraction of component i, and δ1 is the solubility parameter of component 1.) When the polarity of the eluent is increased, it becomes an adsorbent for aldehydes and alcohols. There is a tendency for the adsorption to be small, and therefore a solvent with relatively low polarity having a solubility parameter value of 7 to 12 is suitable as an eluent. Furthermore, in consideration of operability and separation efficiency, it is more preferable to use a solvent with a solubility parameter value of 7 to 9.

Specifically, as the solvent used in the eluent in this method,
Water or methanol, ethanol, propatool,
Alcohols such as isopropyl, phthanol, and imbutanol, ketones such as acetone, methyl ethyl ketone, and diethyl ketone, ethers such as diethyl ether, tetrahydrofuran, and oxane, esters such as ethyl acetate, n-hexane, n- Saturated aliphatic hydrocarbons such as butane, n-octane, 1so-octane, n-decane, cycloaliphatic hydrocarbons such as cyclohexane, cyclopenkune, and tecalin, aromatic hydrocarbons such as benzene, p-xylene, and chlorinated Examples include, but are not limited to, methylene, chloroform, acetonitrile, DMF, DMS○, carbon disulfide, carbon tetrachloride, petroleum ether, and mixtures thereof.

Note that the selection of a solvent for good separation of aldehyde and alcohol can be determined by determining the pulse response or breakthrough response using a single packed column.

The pseudo-moving layer used in this method will be described in detail below with reference to the drawings.

FIG. 1 shows an example of a pseudo moving layer device used in this method. At a certain time, the eluent supply port, alcohol solution (strongly adsorbed component solution) outlet, raw material mixture solution supply port, and altehyde purified solution (weakly adsorbed component solution e7
．． ) are respectively (a), (b), (c) and (
d). In addition to this, an eluent outlet (e) may be provided as necessary. When an eluent outlet (e) is provided, it is necessary to use, for example, a solenoid valve S to shut off the space between (e) and (a). These (a), (b), (e), (d
) and (e) are solenoid valves (D1-12, F7, 1□, E
1-12, R1-12, Efl, 12 and S11,2)
Alternatively, it may be moved intermittently and sequentially in the direction of liquid flow by known means, such as a valve opening/closing device or a rotary valve system. Incidentally, packed tower Cl-12 is filled with chlorine. The packed tower group has liquid supply and extraction ports (a)
, (b), (c) and (d). Packed columns 01-3 are in the first section, packed columns 04-6 are in the second section, packed columns C7-9 are in the third section, packed column C10-
12 is the fourth section. The number of packed columns in each zone is three, and this number can be appropriately determined depending on factors such as separation conditions. The first section acts on desorption of strongly adsorbed components, the second section desorbs weakly adsorbed components, the third section adsorbs strongly adsorbed components, and the fourth section acts on adsorption of weakly adsorbed components.

A concentration distribution of aldehyde and alcohol is formed in the liquid in the packed bed, and the concentration distribution moves downstream as the liquid flows down. Following this movement, the supply port for the raw material mixture solution, the supply port for the eluent, the take-out port for the alcohol solution, and the take-out port for the purified altehyde liquid are sequentially switched to the lower ones. The switching may be performed simultaneously for the four types of apertures, or may be performed for each aperture at different times. The time for which liquid is continued to be introduced or removed from the same opening varies depending on the size of the unit packed columns C1 to C2, the flow rate flowing down within the packed column group, etc., and is usually several minutes to several tens of minutes. .

By this switching, the positions of the four sections described above in the packed column group are moved from time to time. Accordingly, the concentration distribution of each component circulates through the packed column group while maintaining its size and relative position.

The degree of separation of aldehyde and alcohol is influenced by various factors, and the most important factors are the flow rate of the liquid in the packed column group and the duration of continuous supply or withdrawal of the liquid from the same opening. This is because moving the positions of the four types of openings downstream in the liquid flow is equivalent to moving the adsorbent upstream while keeping the opening positions constant, which changes the concentration distribution of each component in the packed bed. is formed by the interaction between the liquid flow and the adsorbent moving upstream. This moving speed is determined for each unit packed column C1-1. It corresponds to the length (L) of ', minus the time (T) for which liquid is continuously introduced or removed from the same opening (L/T). As is well known, in order to separate two components using a pseudo-moving bed, the moving speed of the weakly adsorbed component, that is, alcohol, in the packed bed is V.
1, V in the first section, >L/T, ■>L/T in the second section, V,>L/T in the third section,
In the fourth section, V, <L/T, and the moving speed V of the strongly adsorbed component, i.e., aldehyde, in the packed bed is V, >L/T in the first section, and V, <L in the second section. /T
, V, <L/T in the third section, and V, <L/T in the fourth section.

The moving speed V1 of the weakly adsorbed component in the packed bed and the moving speed V2 of the strongly adsorbed component in the packed bed are determined by the liquid flow rate in the packed bed, or are determined in advance using a batch-type packed column. It can be easily measured. Therefore, the flow rate of the liquid and the time for which the liquid is continuously supplied or removed from the same opening are necessarily determined from these relationships.

Next, the aldehyde fraction obtained as above is distilled at a temperature that does not cause thermal decomposition of the aldehyde. The purified aldehyde is obtained by removing the eluent.

2. Effects of the present invention According to the present invention, alcohol can be separated from a mixture of aldehyde and alcohol without thermal denaturation, etc.
High purity aldehydes can be produced easily and efficiently.

[Example j] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Reference Example A pulse response experiment was conducted to use as a guideline for selecting an eluent. 30jl1 of silica gel was placed in a packed tower with an inner diameter of 1.6cm.
2, and the eluent is kept at a constant space velocity (1 to 2 h').
It was distributed in Then, add 25% by weight of isostearyl aldehyde and instearyl alcohol as an eluent.
It was dissolved at a concentration of Measured by a detector.

Figure 2 shows a mixture of Silica Kel (M, S, GEL D-350-60Δ, manufactured by Shikai Kagaku Kogyo Co., Ltd., as an adsorbent) and hexane and acetone as an eluent at a ratio of 80"1% and 20% by weight, respectively. The value of solubility parameter is 77)
The pulse response curve is shown when using . The horizontal axis is the dimensionless elution time, which is the elution amount e introduced during the time from pulse introduction to elution divided by the adsorbent filling amount.

This shows that instearyl aldehyde and instearyl alcohol elute at dimensionless times of 0.6 and 0.9, respectively, indicating that both components are well separated.

FIG. 3 shows the dimensionless elution time when the polarity of the eluent is changed.

The polarity of the eluent was such that a mixture of hexane and acetone or ethanol/alcohol was used to obtain various solubility parameter values.

From this result, it can be seen that as the polarity of the eluent increases, the elution of instearyl aldehyde and isostearyl alcohol becomes faster.

These pulse response experiments are an effective means for selecting a combination of adsorbent and eluent suitable for use in the pseudo-moving bed in the present invention.

Example A dehydrogenation reaction was carried out using isostearyl alcohol produced from isostearic acid manufactured by Emery Co., Ltd. to obtain a raw material mixture containing 21% by weight of isostearyl alcohol and 66% by weight of isostearyl alcohol. about,
Using this as a raw material, aldehyde was purified.

As shown in Fig. 1, each end of 12 packed columns with an inner diameter of 1.6 cm and a length of 30Cπ is connected to the top of the next packed column by connecting electromagnetic valves S1 to S12 in an endless manner with piping. , liquid extraction pipe height having a solenoid valve upstream of each solenoid valve, R, E
An experimental apparatus was used in which three liquid supply pipes (D, F) with a solenoid valve were branched and connected downstream, and Norikakel (manufactured by Asahi Glass Co., Ltd., N1.F) was used as the adsorbent. S,
Gel D-350-60A) was used to fill each packed column with 6
It was filled with 0.7ρ.

The eluent is supplied from the liquid supply pipe, the raw material is supplied from the liquid supply pipe F, isostearyl alcohol with strong adsorption is taken out from the liquid take-out pipe E, and isostearyl aldehyde, which is weakly adsorbed, is taken out from the liquid take-out pipe R.

Switching of each liquid inlet and outlet at fixed time intervals is D, F, E, R.
This was done by moving the opening/closing positions of the electromagnetic valves , Ef to the downstream of the liquid flow. In this example, the space between (e) and (a) was blocked and an eluent outlet was provided. Therefore, this position also moved downstream of the liquid flow at regular intervals.

The raw material was supplied using a raw material mixture solution in which 50% by weight of the raw material mixture was dissolved in an eluent, and a mixture of hexane and acetone mixed at a ratio of 80% by weight and 20% by weight, respectively, was used as the eluent. was used.

The supply amount and take-out flow rate of each liquid are as follows: Raw material Ua temperature solution
05.45.22 for supply, eluent supply, removal of instearyl alcohol solution, removal of purified isostearyl aldehyde solution, and removal of eluent, respectively.
．． 1.8.1, OB/min, and the supply and removal ports were moved every 20 minutes.

FIG. 4 shows the amount contained in the purified isostearyl aldehyde liquid taken out. The figure shows changes in isostearyl aldehyde and isostearyl alcohol concentrations over time. FIG. 5 shows changes over time in the concentrations of isostearyl aldehyde and isostearyl alcohol contained in the taken out isostearyl alcohol solution. The purity of isostearylaldehyde in the isostearylaldehyde purified liquid in a steady state was 95% by weight, and the recovery rate was 98% by weight. Moreover, the purified isostearyl aldehyde obtained after distilling off the eluent was colorless (Gardner 1).

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of an example of a simulated moving bed device, Figure 2 is the change in elution concentration over time in a pulse response experiment, and Figure 3 is
The relationship between the solubility parameter of the eluent and the dimensionless elution time in the pulse response experiment, and FIGS. 4 and 5 are diagrams showing changes over time in the concentration of the pseudo-moving phase in the ejected solution. Figure 4

Claims (2)

[Claims] (1) A linear or branched saturated or unsaturated aliphatic alcohol having an average carbon number of 10 to 30 and an aliphatic aldehyde obtained by dehydrogenating the alcohol are separated from a raw material mixture. When producing group aldehydes, packed towers filled with silica gel are connected in series through a liquid passage as an adsorption device, and the first packed tower and the last packed tower are also connected through a liquid passage to form an endless structure, so that the solution flows in one direction. An eluent supply port, an alcohol solution takeout port, a raw material mixture solution supply port, and an aldehyde purified liquid takeout port are arranged in each packed tower in this order at predetermined intervals along the direction of the solution flow. However, at the same time as supplying the raw material mixture solution and eluent, an alcohol solution and a purified aldehyde solution are taken out, and a pseudo-moving bed is used, which is made by sequentially moving these supply ports and take-out ports downstream intermittently. Characteristic method for producing aliphatic aldehyde. (2) The solubility parameter value of the eluent is 7 or more and 12
The method for producing an aliphatic aldehyde according to claim 1, using the following solvent.