JP2003040818A - Solvent for extraction and solvent extraction process - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solvent for extraction excellent in chemical stability, having solvent power similar or superior to the conventional solvents for extraction such as halogenated aliphatic hydrocarbons or esters, having a proper boiling point, free from dangers of inhaling vapors of the solvent in solvent extraction process, easy to remove the solvent by vaporization, reducing problems of the environmental contamination, and to provide a solvent extraction method of an organic compound using the same. SOLUTION: This solvent for extraction comprises at least a kind of trifluoromethylbenzene compound expressed by general formula (1) (R is F or a trifluoromethyl group, n is 0, 1 or 2). And the solvent extraction method comprises extraction of the organic compound from a solid or liquid mixture including the organic solvent, has a process contacting the mixture with the solvent for extraction and then separating the solution of the solvent for extraction including the organic solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an extraction solvent comprising a trifluoromethylbenzene compound having at least one trifluoromethyl group in a benzene ring such as trifluoromethylbenzene, and an organic compound, particularly an organic compound having a polar group. Contacting the mixture containing the with the extraction solvent,
The present invention relates to a solvent extraction method for an organic compound, which has a step of separating an extraction solvent solution containing the organic compound.

[0002]

2. Description of the Related Art Solvent extraction methods for extracting a desired compound or composition from a raw material containing the compound or composition as a constituent part by using an appropriate extraction solvent are well known to those skilled in the art. Further, the extraction solvent used in the solvent extraction method has also conventionally been an aliphatic halogenated hydrocarbon such as dichloromethane or chloroform; an aliphatic hydrocarbon such as n-hexane or cyclohexane; an aromatic hydrocarbon such as benzene or toluene. Esters such as methyl acetate and ethyl acetate;
Various compounds such as ketones such as acetone and cyclohexanone; ethers such as diethyl ether and dipropyl ether are known.

As such an extraction solvent, generally,
It is inert under extraction conditions, has excellent solubility in the extract, has an appropriate boiling point, and there is little risk of sucking solvent vapor during solvent extraction operation, and solvent evaporation is easy to remove. , Those with few problems that pollute the environment are required.

However, most of the above-mentioned extraction solvents currently used satisfy all of these requirements. For example, halogenated hydrocarbons such as dichloromethane and chloroform are excellent in dissolving power for various organic compounds, and have a specific gravity of 1 or more. Therefore, when extracting a target solvent from an aqueous solution, it is a preferable extraction solvent in terms of work efficiency. However, since it is generally highly toxic and has a low boiling point, there is a problem that solvent vapor may be inhaled during the extraction work or volatilized to pollute the natural environment. In addition, esters such as ethyl acetate and aromatic hydrocarbons such as toluene are also versatile extraction solvents, but when the solubility for organic compounds having a medium polarity is insufficient and the extraction efficiency is poor. was there. Further, since the specific gravity of these solvents is less than 1, the extraction operation becomes complicated when the solvent is repeatedly extracted from the aqueous solution using these extraction solvents.
Therefore, there is a demand for the development of a new extraction solvent that satisfies the above-mentioned requirements (1) and is advantageous from the viewpoint of extraction work efficiency.

[0005]

DISCLOSURE OF THE INVENTION The present invention has excellent chemical stability and has a dissolving power equal to or higher than that of conventional extraction solvents such as aliphatic halogenated hydrocarbons and esters.
Use an extraction solvent that has an appropriate boiling point, does not have the risk of inhaling solvent vapor during solvent extraction operation, and is easy to evaporate and remove the solvent, and has little problem of polluting the environment. An object is to provide a solvent extraction method for an organic compound.

[0006]

As a result of searching for a new extraction solvent satisfying all the conditions required for the above-mentioned extraction solvent, the present inventors have found that tribenzene having 1 to 3 trifluoromethyl groups on the benzene ring. We have found that fluoromethylbenzene compounds are chemically stable, have an appropriate boiling point, have the same polarity as conventional extraction solvents, are less toxic, and can be an extraction solvent with less environmental pollution problems. ,
The present invention has been completed.

Thus, according to the first aspect of the present invention, the general formula (1)

[0008]

[Chemical 2]

(In the formula, R represents a fluorine atom or a trifluoromethyl group, n represents 0, 1 or 2. When n is 2, R may be the same or different.) There is provided an extraction solvent comprising at least one of the represented trifluoromethylbenzene compounds.

In the extraction solvent of the present invention, the trifluoromethylbenzene compound is preferably trifluoromethylbenzene or 1,3-bis (trifluoromethyl) benzene.

According to a second aspect of the present invention, there is provided a method for extracting an organic compound from a solid or liquid mixture containing the organic compound, which comprises contacting the mixture with an extraction solvent of the present invention, And a solvent extraction method for an organic compound, comprising the step of separating an extraction solvent solution containing the organic compound.

In the extraction method of the present invention, the mixture is preferably an aqueous solution containing an organic compound. Further, the organic compound is preferably an organic compound having a polar group in the molecule, and more preferably an amide compound or a carboxylic acid.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The first aspect of the present invention is an extraction solvent for an organic compound comprising at least one trifluoromethylbenzene compound represented by the general formula (1). In general formula (1), R represents a fluorine atom or a trifluoromethyl group. n is 0, 1 or 2
And when n is 2, R may be the same or different.

The trifluoromethylbenzene compound represented by the general formula (1) is chemically stable, immiscible with water, has a boiling point in the range of 100 to 120 ° C., and has a specific gravity. It is a compound in the range of 1.1 to 1.4.

Specific examples of the trifluoromethylbenzene compound represented by the general formula (1) include trifluoromethylbenzene (boiling point: 102 ° C., specific gravity: 1.199),
1,3-bis (trifluoromethyl) benzene (boiling point:
116 ° C., specific gravity: 1.378), 1,4-bis (trifluoromethyl) benzene (boiling point: 116 ° C., specific gravity: 1.
38), 1-trifluoromethyl-2-fluorobenzene (boiling point: 114 ° C./750 mmHg, specific gravity: 1.29)
3), 1-trifluoromethyl-3-fluorobenzene (boiling point: 101 ° C., specific gravity: 1.302), 1-trifluoromethyl-4-fluorobenzene (boiling point: 102-1)
05 ° C., specific gravity: 1.293) and the like. These can be used alone or in combination of two or more. Among these, in the present invention, availability,
From the viewpoint of solubility and a proper boiling point, trifluoromethylbenzene or 1,3-bis (trifluoromethyl) benzene is preferable.

Further, since the specific gravity of each of these trifluoromethylbenzene compounds is 1 or more, the layer (organic layer) of the trifluoromethylbenzene compound becomes a lower layer when the target substance is extracted from the aqueous solution. Therefore, in the extraction step, the organic layer containing the target substance only needs to be separated from the lower side, and the work efficiency of the extraction operation is good.

Many of the trifluoromethylbenzene compounds represented by the general formula (1) are known substances and are commercially available. In addition, the trifluoromethylbenzene compound represented by the general formula (1) is, for example, the Merck Index.
Twelfth Edition, 1142, Beil. , 5 (3), 853,
J. Fluorine Chem. , 55, 225 (1
991), J. Fluorine Chem. , 61,
279 (1993), J. Chem. Soc. Che
m. Commun. , (1989) 705, Japanese Patent Laid-Open Publication No.
It can also be produced by the methods described in JP-A-14711, JP-A-11-341542, JP-A-2000-34239 and the like.

Secondly, the organic compound is contacted with the extraction solvent of the present invention from a solid or liquid mixture containing the organic compound, and then the extraction solvent solution containing the organic compound is separated. It is the solvent extraction method of the organic compound which has a process. The solvent extraction method of the present invention can be preferably applied particularly to a step of separating and purifying a target organic compound from a reaction product of an organic synthetic chemical reaction.

The organic compound to be extracted is not particularly limited as long as it is soluble in the trifluoromethylbenzene compound represented by the general formula (1), but the extraction solvent of the present invention is a conventional extraction solvent. From the perspective of being an alternative
Organic compounds having good solubility in conventional extraction solvents such as aliphatic halogenated hydrocarbons, esters and aromatic hydrocarbons are preferred.

Examples of such organic compounds include organic compounds having a polar group in the molecule. Here, the polar group refers to a group containing an atom having a different electronegativity from a carbon atom such as an oxygen atom, a nitrogen atom, and a sulfur atom, for example, an amide group, a carboxyl group, an ester group, a hydroxyl group, a carbonyl group. , Amino group, nitro group, cyano group, alkoxy group, mercapto group, alkylthio group and the like.

Examples of the organic compound having a polar group in the molecule include natural products having one or more polar groups in the molecule, active ingredients such as pharmaceuticals and agricultural chemicals, industrial chemicals, fragrances and intermediates for producing these. Can be mentioned. The molecular weight of the organic compound is not particularly limited, but is usually 100 to 500, preferably 100 to 300.

In the present invention, among these organic compounds, the organic compound to be extracted is particularly preferably an amide compound having an amide bond in the molecule as a polar group or a carboxylic acid having a carboxyl group.

When the organic compound to be extracted has an asymmetric carbon in the molecule, the organic compound may be a mixture of optical isomers or one of the optical isomers. The racemization reaction does not proceed in the operation.

As a method of solvent extraction, for example, a solution in which an extraction solvent immiscible with the solvent is added to a solvent solution containing the organic compound, and the organic compound is transferred to the extraction solvent by utilizing the difference in partition coefficient. -Liquid extraction method, a solid-liquid extraction method in which an extraction solvent is added to a solid mixture containing an organic compound, and the organic compound is extracted with the extraction solvent. The present invention is particularly suitable when an organic compound is extracted with an aqueous solution containing an organic compound using the extraction solvent of the present invention.

As the liquid-liquid extraction method, more specifically,
(i) To an aqueous solution of an organic compound that is soluble in water and an organic solvent and is more soluble in an extraction solvent than water, after adding the extraction solvent of the present invention and thoroughly shaking it, let it stand still. To separate the water layer and the organic layer into two layers, and separate the organic layer, (ii)
To an aqueous solution of a salt of an acidic organic compound such as carboxylic acid or a salt of a basic organic compound, an acid is added to release the acidic compound in the case of the salt of the acidic compound, and a base is added in the case of the salt of the basic compound. Examples thereof include a method in which the basic compound is added to liberate the basic compound, and the liberated acidic organic compound or basic organic compound is extracted with the extraction solvent of the present invention. In this case, the extraction operation may be repeated several times. The extraction temperature is usually -20 ° C to 100 ° C, preferably 0 ° C to 90 ° C.
C., more preferably in the range of 20 to 50.degree.

When the liquid-liquid extraction method is used, a separatory funnel is used when it is carried out at a laboratory level, and a well-known separator (mixer settler), multistage is used when a large amount of treatment is carried out. A mixer / decanter type contactor, a gravity separation column type contactor, etc. can be used.

When a separating funnel is used, an appropriate amount of the extraction solvent of the present invention is added to an aqueous solution containing the compound to be extracted and shaken well. Then, the mixture is left standing to completely separate into two layers, an organic layer and an aqueous layer, and then the organic layer is separated.

Known liquid separating apparatus (mixer settler)
Uses a large separatory funnel, and can be performed according to the method using a separatory funnel at the laboratory level. A multi-stage mixer / decanter type contactor is a non-stirring type extraction device, and typically, a light liquid (such as an aqueous solution) having a smaller specific gravity from the lower side of the extraction column and a heavy liquid having a higher specific gravity from the upper side ( The extraction solvent of the present invention) is respectively supplied. In this device, the light liquid goes upwards,
Since the heavy liquids flow downwards, respectively,
Two liquids come into contact. Then, the components dissolved in the light liquid or the heavy liquid are distributed into each liquid phase according to the distribution coefficient.
In this case, when the porous plates are installed in multiple stages in the extraction tower, the light liquid rises as droplets from the small holes formed in the porous plate and comes into contact with the heavy liquid. A large number of droplets are further raised as droplets from the next small holes of the porous plate. By repeating the formation and coalescence of droplets in this way, it is possible to effectively bring the two liquids into contact with each other. Further, the gravity fractionation type contactor is an extraction device for performing mechanical agitation, and examples of the agitation method include a method of agitating with a stirring blade, a method of agitating by sending a pulse and the like.

As the solid-liquid extraction method, specifically, after the solid mixture containing the organic compound to be extracted and the extraction solvent of the present invention are sufficiently mixed, the desired organic compound is extracted. And a method of removing insoluble matter by a method such as filtration. Prior to the extraction, it is preferable to pulverize the solid mixture in order to further improve the extraction efficiency. The extraction solvent may be heated during extraction.

The extraction device used for the solid-liquid extraction is, for example, a type in which a filter cloth or a perforated plate is installed at the bottom, the solid containing the extract is allowed to stand still, and the extraction solvent of the present invention is circulated. A known extraction device such as the extraction device of the above can be used. Further, when a large amount of solid-liquid extraction treatment is performed, for example, the continuous extraction device described in JP-A-9-510913 can be used.

In any case, the extraction solvent layer (solution) of the present invention is separated and, if necessary, dried to remove the extraction solvent of the present invention. The obtained residue can be purified by a known purification method such as solvent washing, recrystallization, column chromatography, and distillation to isolate the desired product. If the extract is a heat-labile compound such as a natural product, it is necessary to remove the extraction solvent under reduced pressure or to inject steam to reduce the partial pressure of the solvent (steam stripping). There are some cases. Further, the extraction solvent of the present invention can be recovered by a solvent recovery device and, if necessary, subjected to a purification treatment such as distillation, and then used again as an extraction solvent.

[0032]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the following examples, and the type of the extraction solvent trifluoromethylbenzene compound and the subject of extraction are shown. The type of organic compound can be freely changed without departing from the gist of the present invention.

Example 1 Extraction of Amide Compounds of Moderate Polarity

[0034]

[Chemical 3]

6 g of the compound A represented by
It was dissolved in 1. Put this aqueous solution in a 500 ml separatory funnel, add 120 ml of trifluoromethylbenzene, and add 5
After sufficiently shaking for 1 minute, the mixture was allowed to stand and the organic layer (trifluoromethylbenzene layer) was separated. This extraction operation was repeated once more, the organic layers were collected, and the solvent was distilled off under reduced pressure. As a result of quantifying the obtained residue, it was found that 99% or more of Compound A was extracted into trifluoromethylbenzene.

EXAMPLE 2 Extraction of Amide Compounds of Moderate Polarity In Example 1, trifluoromethylbenzene 120
The extraction operation was performed in the same manner as in Example 1 except that 120 ml of 1,3-bis (trifluoromethyl) benzene was used instead of ml. It was found that 99% or more of Compound A was extracted into 1,3-bis (trifluoromethyl) benzene.

Compound A is an intermediate for the production of antihypertensive agents having an amide bond (amide group) in the molecule. That Rf
The value is 0.55 (developing solvent; methanol: ethyl acetate =
1:10) with moderate polarity. Conventionally, compound A was extracted from an aqueous solution of compound A by extracting with ethyl acetate three times. Example 1
According to 2 and 2, it was found that the compound A can be quantitatively extracted by two extractions.

Example 3 Extraction of Carboxylic Acid from Lower Carboxylate

[0039]

[Chemical 4]

3 g of the (+)-α-methylbenzylamine salt of compound B represented by the following is dissolved in 15 ml of 2M hydrochloric acid aqueous solution, the solution is put into a 200 ml separating funnel, and 60 ml of trifluoromethylbenzene is added. After sufficiently shaking for 5 minutes, the mixture was allowed to stand and the organic layer (trifluoromethylbenzene layer) was separated. As a result of quantifying the residue obtained by distilling off the solvent from the organic layer under reduced pressure, it was found that 99% or more of compound B was extracted into trifluoromethylbenzene.

Example 4 Extraction of Carboxylic Acid from Lower Carboxylate In Example 3, trifluoromethylbenzene 60 m
The extraction operation was performed in the same manner as in Example 1 except that 60 ml of 1,3-bis (trifluoromethyl) benzene was used instead of 1. It was found that 99% or more of Compound B was extracted into 1,3-bistrifluoromethylbenzene.

Compound B is a carboxylic acid and an intermediate in the production of certain antihypertensive agents. Its Rf value is 0.50
(Developing solvent; n-hexane: ethyl acetate = 3: 1) and has a medium polarity. Conventionally, compound B has been extracted by extracting twice with dichloromethane. According to Examples 3 and 4, it was found that Compound B can be quantitatively extracted by one extraction.

Comparative Example 1 Extraction of an Amide Compound of Moderate Polarity with Dichloromethane Example 1 except that 120 ml of dichloromethane was used instead of 120 ml of trifluoromethylbenzene in Example 1.
An extraction experiment was conducted in the same manner as in. After performing the extraction operation twice, the organic layer (dichloromethane layer) was collected, and the solvent was evaporated under reduced pressure. As a result of quantifying the obtained residue, it was found that 80% of compound A was extracted into dichloromethane.

As described above, the extraction solvent of the present invention is excellent in chemical stability and has a dissolving power equal to or higher than that of conventional extraction solvents such as aliphatic halogenated hydrocarbons and esters. However, it is a highly versatile extraction solvent that has a low risk of sucking solvent vapor during a solvent extraction operation, has a proper boiling point that allows the solvent to be easily distilled off, and has a small problem of polluting the environment. Further, according to the method for separating an organic compound of the present invention, various organic compounds, preferably an organic compound having a polar group in the molecule, more preferably an amidation compound having an amide group in the molecule and a carboxyl group in the molecule. A carboxylic acid having a group can be efficiently extracted.

Front page continuation (51) Int.Cl. ⁷ identification code FI theme code (reference) C07C 51/48 C07C 51/48 57/18 57/18 C07F 7/18 C07F 7/18 T 7/20 7/20

Claims (6)

[Claims] 1. A general formula (1): (In the formula, R represents a fluorine atom or a trifluoromethyl group, n represents 0, 1 or 2. When n is 2, R represents
May be the same or different. ) An organic compound extraction solvent comprising at least one trifluoromethylbenzene compound represented by 2. The extraction solvent for an organic compound according to claim 1, wherein the trifluoromethylbenzene compound is trifluoromethylbenzene or 1,3-bis (trifluoromethyl) benzene. 3. A method for extracting an organic compound from a solid or liquid mixture containing an organic compound, which comprises contacting the mixture with the extraction solvent according to claim 1 or 2, and then removing the organic compound from the mixture. A method for extracting a solvent of an organic compound, comprising a step of separating the contained extraction solvent solution. 4. The solvent extraction method according to claim 3, wherein the mixture is an aqueous solution containing an organic compound. 5. The solvent extraction method according to claim 3, wherein the organic compound is an organic compound having a polar group in the molecule. 6. The solvent extraction method according to claim 3, wherein the organic compound is an amide compound or a carboxylic acid.