JPH10151301A - Method for separating or purifying material from mixed solution by crystallization - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve recovery efficiency by controlling the concentration of a coexisting component in a crystallizing solution system to a specific value and crystallizing an objective material in the case of separating or purifying the objective material crystal from a mixed solution by crystallization at a higher temp. than the crystallization tamp. of a crystalline material to be separated or purified. SOLUTION: At the time of isolating and purifying resorcinol from the mixed solution obtained by the oxidation of diisopropylbenzene and containing the coexisting component, which is phase separated at the higher temp. than the crystallization temp. of resorcinol, by the crystallization, the objective material is crystallized by controlling the concentration of the coexisting component in the crystallizing solution system to <=1.5wt.%. A device for crystallizing in this way is constituted so as to add a distillate, an adjusting liquid and toluene into a crystallization vessel 1 with a jacket, to which a stirring blade 2 and a condenser 3 are attached, and after that, to pass a hot water in the jacket. And gaseous N2 is blown from a N2 blowing pipe 6 to entrain toluene/water in a vapor state and the toluene/water is condensed and stored in a liquid/liquid separating cylinder 5 to remove the separated water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently separating or purifying a high-purity compound or a crystalline substance such as a simple substance from a mixed solution by crystallization. In particular, it is suitable for a method for separating or purifying resorcinol from a reaction product mixture solution system, and furthermore, meta-dihydroperoxide (m-DH) obtained by oxidation of meta-diisopropylbenzene (m-DIPB).
The present invention relates to a purification method by crystallization, which is particularly suitable for isolating and purifying resorcinol from a mixed solution of an acid decomposition product of P).

[0002]

BACKGROUND OF THE INVENTION As a method for separating or purifying a substance such as a compound or a simple substance from a mixture system, various methods such as distillation, extraction, and sublimation are known. When it is difficult to apply other separation and purification means such as distillation, or it is difficult to implement industrially, or when it is expensive, if the substance is a crystallizable compound or a substance such as a simple substance, It is well known that crystallization is often applied for purification.

[0003] However, the state of the feed mixture system to be subjected to crystallization, ie, the type of the compound or the like for the purpose of separation or purification, the type of the coexisting components other than the target product, and the quantitative analysis of the content of those components Depending on the relationship, crystallization temperature, pressure,
In many cases, no matter how much the operating conditions such as the crystallization solvent are changed, the compound cannot be purified to the desired purity.

[0004] One example of such a case is the isolation and purification of resorcinol from a reaction mixture. That is, meta-diisopropyl peroxide (m-DHP) is obtained by oxidizing meta-diisopropylbenzene (m-DIPB) with molecular oxygen in the presence of a base. When this m-DHP is acid-decomposed, resorcinol and acetone are converted. It is well known that, when oxidatively decomposing an oxidation product containing m-DHP obtained by oxidation of m-DIPB, it is dissolved in a water-insoluble solvent such as aromatic hydrocarbons and dialkyl ketones. A method of extracting m-DHP and decomposing it by acid is also known. Further, from m-DIPB to m
There is also known a method of adding an aqueous hydrogen peroxide solution to the oxidation reaction product of m-DIPB to further oxidize the product in order to improve the conversion to -DHP (Japanese Patent Application Laid-Open No. 53-23939).

When an oxidation reaction product containing m-DHP obtained by oxidation of m-DIPB is acid-decomposed, m-isopropylphenol (hereinafter referred to as m-isopropylphenol) as a by-product in addition to the production of resorcinol and acetone. IP
P) and m-isopropenylphenol (hereinafter m-isopropenylphenol)
Olefins such as IPeP), m-hydroxy-α,
carbinols such as α-dimethylbenzyl alcohol (m-CP) and m-hydroxyacetophenone (hereinafter referred to as m-CP);
HA), m-isopropenylacetophenone (hereinafter m-isopropenylacetophenone)
High-boiling substances such as 4- (3-hydroxycumyl) resorcinol (hereinafter, CP-RS), in which ketones such as IPeA) or resorcinol and m-IPeP are further reacted, are also produced. As a method of recovering resorcinol from such an acid decomposition mixture, conventionally, acetone and water are removed in a deacetone tower and a dehydration tower, respectively, and then the water-insoluble solvent is removed in a desolvation tower.
Alternatively, after removing acetone, separating oil / water, removing water in a dehydration tower (JP-A-64-38), and purifying resorcin by distillation or crystallization.

However, in distillation, some of the high-boiling substances are decomposed into lower-boiling substances during the distillation, and some of the decomposed impurities have a boiling point similar to that of resorcinol, and some of the decomposed impurities have the same boiling point as resorcinol. There is a problem that it is difficult to efficiently obtain high-purity resorcinol in a high yield by ordinary distillation because a boiling system is formed.

On the other hand, when a purification method by crystallization is employed in order to avoid such inconvenience of the purification method by distillation, in this method, a crystallization solvent is used as a crystallization solvent in view of the purity of the obtained product, the resorcinol recovery rate, and the like. Non-water-soluble solvents such as aromatic hydrocarbons and dialkyl ketones are used. In this case, when the crystallization liquid system contains a certain amount of water or the like, the purity and recovery of resorcinol are often increased. An unfortunate situation occurs in which the temperature decreases. The present inventors have studied various methods for obtaining high-purity resorcinol with high yield in a stable manner by crystallization from a mixed liquid system containing resorcinol, unreacted raw materials, reaction by-products, impurities, solvents, water, and the like. In the course of experiments and studies, during the process of cooling the mixed liquid system to precipitate the target product, resorcin, before the temperature at which the resorcinol is crystallized, other components such as water are allowed to react. In a system that separates and produces, for example, turbidity, the crystallized resorcin obtained by further cooling such a mixed system has a high purity and such turbidity (phase separation) is observed. It was found that the purity was remarkably inferior to the purity of resorcinol crystallized from the system which did not exist, and the yield was low.

[0008] Based on this finding, and further studies on separating and purifying the target substance from various other mixed liquid systems by crystallization have been repeated. As a result, other than the above-mentioned resorcinol-containing systems,
In a mixed liquid system containing coexisting components such as water that separates from the crystallization system at a temperature higher than the crystallization temperature of the target product, the crystallization liquid system is used in the process of separating or purifying the target compound by crystallization. If the entire solution is cloudy (phase separation) instead of crystallizing at the temperature during cooling to the crystallization temperature of the product, the target substance crystallized by lowering the temperature further has its purity and recovery. Was found to be significantly lower than the purity and recovery of the crystallization of the system in the absence of turbidity.

Further, in such a crystallization system, the phase-separated substance in the system is removed by a means such as removing a phase-separated substance such as water before the temperature at which the target substance is crystallized. When the content is controlled to be 1.5% by weight or less, the inconvenience described above can be avoided.
Based on this finding, the present invention has been completed.

[0010]

Accordingly, an object of the present invention is to solve the above-mentioned problems when separating or purifying a target substance from a mixed solution by crystallization, and to obtain a high-purity target substance in good yield. An object of the present invention is to provide an improved crystallization method. In particular, as one embodiment of the above method, m-DIPB
An object of the present invention is to provide a method for purifying resorcinol which can obtain high-purity resorcinol at a high recovery rate by crystallization from an acid decomposition product obtained by acid-decomposition of m-DHP obtained by oxidizing m-DHP.

[0011]

According to the present invention, the target crystal is separated by crystallization from a mixed solution containing a coexisting component which is phase-separated at a temperature higher than the crystallization temperature of the crystalline substance to be separated or purified. Or a method of purifying, wherein the target substance is crystallized after controlling the concentration of the coexisting component in a crystallization treatment liquid system containing a crystallization solvent to 1.5% by weight or less. Is provided.

In the method of the present invention, the concentration of the phase-separated contaminants such as water is adjusted to 1.5% by weight or less in the system before the crystallization of the target crystal starts from the crystallization system. It is particularly important that the crystallization operation is sometimes performed in a state where impurities such as water do not cause phase separation.

Thus, as described above, the target compound and other substances can be isolated from the mixed liquid system with high purity. Even if the impurities such as water are removed after the crystallization of the target substance is started and the concentration in the system is 1.5% by weight or less, the effect of the present invention cannot be obtained.

[0014] The mechanism by which this effect of the method of the present invention is achieved is not yet fully understood. For example, in a typical case where the method of the present invention is applied. When resorcinol is crystallized and purified from a reaction mixture obtained by oxidation and acid decomposition of a certain meta-diisopropylbenzene (m-DIPB), water, m-isopropylphenol (m) together with acetone and resorcinol are contained in the reaction product solution. -IPP), m-isopropenylphenol (m-IPeP), m-hydroxy-a,
a-dimethylbenzyl alcohol (m-CP), m-hydroxyacetophenone (m-HA), m-isopropenylacetophenone (m-IPeA), 4- (3-hydroxycumyl) resorcinol (CP-RS), and many others. Contains by-product impurities.

Further, resorcin itself, which is a target product present in the system, has a good compatibility with water and has considerable compatibility, and among the by-product impurities, there is a large compatibility with water. Many compounds have the following formula:

Accordingly, the water present in the system exists as a mixed solution in a state of being compatible with these organic compounds. When a crystallization solvent is added to such a mixed system and the temperature is lowered to crystallize resorcinol as it is, an aqueous phase containing organic impurities having an affinity for water is formed in a dispersed state during crystallization, and this precipitates. Adsorbed or occluded by the resorcinol crystals. Organic impurities contained in the aqueous phase are weakly bonded to resorcinol by hydrogen bonding or the like, and some of the physical properties such as the boiling point are similar to those of resorcinol.
Once adsorbed, it is difficult to separate easily by ordinary means.

According to the present invention, in a system in which it is difficult to obtain a high-purity crystal of the target compound by such ordinary crystallization means, before the crystallization of the target compound is started, the crystal is separated from the crystal after the crystallization. The purity of the crystallized crystal is improved by removing the aqueous phase containing an organic impurity which is difficult to separate and remove to a specific concentration or less.

[0018]

The crystallization method of the present invention is applied to a mixed liquid system containing a coexisting component that separates phase at a temperature higher than the crystallization temperature of the target crystalline substance, and is incorporated into a processing liquid system containing a crystallization solvent. It is characterized by controlling the content of the co-existing component to 1.5% by weight or less to crystallize the target product. The target compound to be purified is an aromatic compound having at least one of a hydroxyl group, a carbonyl group, and a carboxyl group, or an aromatic compound having a combination of these substituents in the molecule, and other than the target compound. And a mixed liquid system containing water, an organic solvent and the like.

Specifically, for example, an aromatic compound having a phenolic substituent such as phenol, cresol, nitrophenol, aminophenol, hydroxybenzoic acid, hydroxybenzaldehyde, catechol, hydroquinone, or naphthol may be used in addition to the above-mentioned resorcinol. For example, a case of separation and purification from a reaction product mixture containing the compound can be mentioned.

Hereinafter, the present invention will be described by taking, as an example, the case where resorcinol is crystallized and purified from a reaction mixture obtained by oxidation and acid decomposition of meta-diisopropylbenzene (m-DIPB) to which the method of the present invention is most suitably applied. Will be described more specifically.

When acid-decomposing an oxidation reaction product containing meta-dihydroperoxide (m-DHP) obtained by oxidation of m-DIPB, m-DIPB is mixed with a water-insoluble solvent such as an aromatic hydrocarbon or dialkyl ketone. A method of extracting and acid-decomposing DIPB is generally performed. Furthermore, m-DI
M-D to improve the conversion of PB to m-DHP
It is also common practice to add aqueous hydrogen peroxide to the oxidation reaction product of IPB for further oxidation.

When the oxidation reaction product containing meta-dihydroperoxide (m-DHP) obtained by oxidation of m-DIPB is acid-decomposed, m-isopropylphenol and m-isopropylphenol are produced as by-products in addition to the formation of resorcinol and acetone. Alkyl-substituted phenols such as -isopropenylphenol, carbinols such as m-hydroxy-α, α-dimethylbenzyl alcohol, ketones such as m-hydroxyacetophenone and m-isopropenylacetophenone, and the alkyl-substituted phenols and resorcinol Various high-boiling impurities such as 4- (3-hydroxycumyl) resorcinol are simultaneously produced.

As a method on an industrial scale for recovering resorcinol from these acid decomposition mixtures, usually, first, acetone and water are separated and removed in a deacetone tower and a dehydration tower, respectively, and then a water-insoluble solvent is removed in a desolvation tower. After removing or removing acetone, oil / water separation is carried out by a separator, water is further removed by a dehydration tower, and then resorcin is purified and isolated by distillation or crystallization. . The present invention aims to obtain high-purity resorcinol at a high recovery rate by controlling the water concentration in the system at the time of crystallization in this crystallization step.

In the crystallization method of the present invention, a crystallization solvent is added during crystallization of the liquid to be treated,
Although not necessarily limited thereto, a water-insoluble organic solvent is used as a crystallization solvent. Suitable as such a crystallization solvent are aromatic hydrocarbon solvents such as benzene, toluene, xylene, ethylbenzene, and a mixed solvent thereof; and aliphatic hydrocarbons such as hexane, heptane, octane, and a mixed solvent thereof. Solvent, MEK, diethyl ketone, dipropyl ketone, dibutyl ketone, MIBK
Water-insoluble dialkyl ketone solvents, such as diethyl ether, dipropyl ether, dibutyl ether, and the like, and mixed solvents thereof.

Further, in addition to the above-mentioned solvent, a residual mother liquor (raffinate) after crystallization of the target product previously crystallized may be added.

In the present invention, the mixed solution to which the above-mentioned solvent, raffinate (crystallization residue mother liquor) and the like are added is used as a treatment liquid for crystallization, and the temperature of the liquid is gradually lowered. Before depositing the target crystal, it is necessary to control the water content of the crystallization system to 1.5% or less in advance before the crystal is deposited, preferably to 1% or less, particularly to 0.5% or less. It is preferable to control the water content in the crystallization system. The solvent concentration is 10 to 90%, preferably 30 to the total amount of the liquid fed to the crystallization tank and the crystallization mother liquor.
To 80%, more preferably 40 to 70%.

In the method of the present invention, as a method for controlling the water content of the crystallization system to 1.5% or less, specifically, the liquid to be treated for crystallization is distilled under reduced pressure to remove impurities such as water. A method of removing a phase separation component, a method of blowing an inert gas such as N ₂ into a liquid system to be treated and removing a component such as water into the gas in a vapor state, using a dehydrating agent such as molecular sieve or the like. Dehydration methods and the like can be exemplified. Among them, a method of removing water under reduced pressure and a method of blowing an inert gas into the liquid system to be treated are particularly preferable.

Examples 1 to 5 and Comparative Examples 1 to 3 m-diisopropylbenzene (m-DIPB) was oxidized with molecular oxygen in the presence of a base, and toluene was added to the resulting reaction mixture as a water-insoluble solvent. , Then wash with water to remove the base,
After obtaining m-dihydroperoxide containing m-hydroxyhydroperoxide (m-HHP), this is reoxidized with hydrogen peroxide in the presence of sulfuric acid, and the resulting reoxidized product is acid-decomposed by an acid catalyst. As a result, a crude resorcinol containing acetone, water, toluene and the like was obtained.

After removing the catalyst, acetone,
Water and toluene are distilled off, and then pyrolysis / distillation is performed to obtain 2
Various kinds of distillates (crystallization raw materials: Table 1) were obtained.

[0030]

[Table 1] Note: m-IPP m-isopropylphenol m-IPeP m-isopropenylphenol m-HA m-hydroxyacetophenone RS resorcinol CP-RS 4- (3-hydroxycumyl) resorcinol B Total The boiling point is lower than that of RS and represents the sum of substances other than water, m-IPP, m-IPeP and m-HA. H. B Total Higher boiling point than RS and represents the sum of substances other than CP-RS.

The crystallization solvent, together with the aromatic hydrocarbon, is shown in Table 2.
The residual mother liquor (raffinate) obtained after crystallization of the distillate obtained by pyrolysis / distillation having the composition shown in Table 2 was used (however, Table 2).
Is the same as the liquid composition of the raffinate.

[0032]

[Table 2]

The crystallization was carried out as follows using the apparatus shown in FIG. (I) The pyrolysis / distillation distillate shown in Table 1 (hereinafter referred to as distillate), the preparation shown in Table 2 and toluene are added to a 500-ml separable flask with a capacity shown in FIG. (Ii) After attaching the stirring blade, condenser, and thermowell, pour warm water through the jacket to reduce the temperature in the flask to 9
Increase to 5 ° C or higher. (Iii) Dissolve the distillate completely at a stirring speed of 500 rpm. (Iv) 1-20 L / m of N ₂ gas from the N ₂ blowing pipe
in at a flow rate of in, bubbling in the mixture,
Toluene / water is entrained in vapor form and led to a condenser, cooled in the condenser to condense toluene / water,
The condensate is collected in a liquid / liquid separation tube and the separated water is removed. (V) The above operation (iv) is continued until the water content in the flask content becomes 1.5% or less, and after the water content is sufficiently removed, the internal solution is cooled to 55 ° C. at a cooling rate of 0.3 ° C./min. Cool down to (Vi) Remove the stirring blade, condenser and thermowell, transfer the contents to a small centrifuge, and perform solid / liquid separation. (Vii) Distillate 1 was added to the centrifuged solid (cake).
Sprinkle and rinse 50 parts of toluene with 00 parts. (Viii) Drying is performed at room temperature under a vacuum of 30 mmHg for 4 hours. The resorcinol (RS) obtained as described above and N ₂ as a comparative example were not blown, and the water content in the inner solution was 1.5%.
%, And the results of each quality evaluation of RS obtained by the crystallization treatment in the same manner as described above, except that the content is not less than 0.1%.

[0034]

[Table 3] RS recovery rate: (RS amount in cake / RS amount before crystallization) × 100

[0035]

[Table 4] RS recovery rate: (RS amount in cake / RS amount before crystallization) × 100

From [0036] Tables 3 and 4, by reducing the water content before crystallization by blowing Examples 1-3 In N _2, N ₂
RS (resorcinol crystal cake) has a higher purity than Comparative Examples 1 to 3 under the same conditions except that
Also, it can be seen that the recovery rate is high. [Example 6, Comparative Example 4] R was prepared in the same manner as in Example 1 or Comparative Example 1 except that para-xylene was used for the solvent and the rinsing liquid.
Table 5 shows the results of evaluating S (Example 6, Comparative Example 4).

[0037]

[Table 5] RS recovery rate: (RS amount in cake / RS amount before crystallization) × 100

[0038]

According to the crystallization purification method of the present invention, by controlling the water concentration in the system in the crystallization tank, it is possible to remove a mixture system which is difficult to purify with high purity by the conventional ordinary crystallization method. A high-purity target substance can be obtained at a high recovery rate.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a crystallization apparatus (an experimental apparatus) used in the crystallization method of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Changsing tank (with jacket) 2 Stirrer blade 3 Condenser 4 Thermocouple 5 Liquid / liquid separation tube 6 Inert gas injection tube 7 Motor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C07C 39/08 C07C 39/08 (72) Inventor Masamitsu Matsuno 6-1-2, Waki, Waki-machi, Kuga-gun, Yamaguchi Prefecture Mitsui Petrochemical Inside the Industrial Co., Ltd. (72) Masayuki Takeda 1-2-1, Waki, Waki-machi, Kuga-gun, Yamaguchi Prefecture Inside Mitsui Petrochemical Industry Co., Ltd. No. 2 Inside Mitsui Petrochemical Industry Co., Ltd.

Claims (8)

[Claims] 1. A method for separating or purifying a target crystal by crystallization from a mixed solution containing a coexisting component which is phase-separated at a temperature higher than the crystallization temperature of a crystalline substance to be separated or purified, the method comprising the steps of: A method for separating or purifying a crystalline substance, comprising: controlling the concentration of the coexisting component in a crystallization treatment liquid system containing 1.5% by weight or less, and then crystallizing the target substance. 2. The method according to claim 1, wherein the control of the concentration of the coexisting component is achieved by adjusting the pressure of a crystallization system.
The described method. 3. The control of the concentration of the coexisting component is achieved by blowing a gas into the crystallization system, and discharging the coexisting component out of the system by entraining the coexisting component in the gas in a vapor form. Item 7. The method according to Item 1. 4. The crystalline substance to be separated or purified is an aromatic compound having at least one substituent selected from the group consisting of a hydroxyl group, a carbonyl group and a carboxyl group. 3. The method according to any one of claims 1 to 2. 5. The method according to claim 1, wherein the coexisting component for phase separation is water or an alcohol or a mixture thereof. 6. The method according to claim 1, wherein the crystallization solvent used for crystallization is an aromatic compound. 7. The method according to claim 6, wherein the crystalline substance to be separated or purified is resorcin, the crystallization solvent is toluene, and the coexisting component for phase separation is water. 8. The method according to claim 1, wherein resorcinol is isolated and purified from a reaction product mixture containing resorcinol obtained by oxidizing meta-diisopropylbenzene and acid-decomposing a generated peroxide. The described method.