JP2008279348A - Crystallization method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crystallization method which enables the crystallization of a substance dissolved in water and does not give rise to a scaling phenomenon. <P>SOLUTION: This crystallization method includes: the aqueous solution preparation process of preparing an aqueous solution containing a substance intended for crystallization and water; the mixed solution preparation process to mix an organic solvent which does not dissolve the substance, neither does mix with water and can cause azeotropy with water, with the aqueous solution obtained by the aqueous solution preparation process; and the crystallization process to crystallize the substance by performing the azeotropic distillation of water and the organic solvent from the mixture solution obtained by the mixture solution preparation process. In the crystallization process, the water and the organic solvent are azeotropically distilled from the mixture solution in the presence of a water-insoluble particle which has hydrophilic nature in at least the surface, in a crystallization tank 2 of the crystallization device 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a material crystallization method, for example, an organic compound evaporation crystallization method.

  Conventionally, as an evaporation crystallization method for taking out crystals of an organic compound, a compound dissolved or dispersed in an organic solvent is dropped into water, and the organic solvent and water in the obtained suspension are azeotroped. A method is known in which a compound in a suspension is extracted as crystals by distillation.

  For example, in Patent Document 1, a solution obtained by dissolving or dispersing an organic compound in an organic solvent is supplied to water having a temperature condition that is equal to or higher than the boiling temperature of the organic solvent and equal to or lower than the melting point of the organic compound. It is a method of agitating them and evaporating the organic solvent (azeotropic distillation with water) to crystallize the organic compound, and in particular, an evaporating crystal that supplies a solution or suspension of the organic compound below the water surface The analysis method is shown.

  In Patent Document 2, a solution obtained by dissolving or suspending an organic compound in an organic solvent is supplied to water having a temperature condition that is equal to or higher than the boiling temperature of the organic solvent and equal to or lower than the melting point of the organic compound. This is a method of crystallizing an organic compound by stirring them and evaporating the organic solvent. In particular, evaporation in which a solution or suspension of the organic compound is supplied in the water near the stirring blade and in the direction of water flow. A crystallization method is shown.

In Patent Document 3, a solution obtained by dissolving or suspending an organic compound in an organic solvent is supplied to water having a temperature condition not lower than the boiling point of the organic solvent and not higher than the melting point of the organic compound. Furthermore, they are stirred and the organic solvent is evaporated to crystallize the organic compound. In particular, the amount of liquid in the stirring vessel is adjusted so that the stirring power per unit volume (kW / m ³ ) is constant. A crystallization method is shown in which the rotation speed of the stirring blade is controlled in accordance with the fluctuation.

  By the way, as an acid generator that gives a resist having an excellent pattern shape, for example, Patent Document 4 discloses an acid generator represented by the general formula (2).

(In the formula, Q ₁ and Q ₂ each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, X represents —OH or —Y—OH, and Y represents a straight chain having 1 to 6 carbon atoms. Represents a chain or branched alkylene group, n represents an integer of 1 to 9, and A ⁺ represents an organic counter ion.)
As an intermediate of the acid generator, for example, Patent Document 4 discloses an organic compound represented by the general formula (1). Specifically, the fluorosulfonyl carboxylic acid methyl ester of the organic compound represented by the general formula (1) is hydrolyzed with sodium hydroxide to obtain an aqueous solution, and the carboxylic acid is esterified with the aqueous solution. It is disclosed.

(In the formula, Q ₁ and Q ₂ each independently represent a fluorine atom or a C 1-6 perfluoroalkyl group, and M represents Li, Na, K, or Ag.)
However, as described above, a method for extracting an organic compound as a crystal from an aqueous solution in which the organic compound is dissolved in water has not been known.
Japanese Patent Laid-Open No. 11-290601 (released on October 26, 1999) JP 2001-104703 A (published April 17, 2001) JP 2004-209434 A (published July 29, 2004) JP 2006-257078 A (published September 28, 2006)

  When an organic compound represented by the general formula (1), which is an example of an aqueous solution in which an organic compound is dissolved in water, is esterified as it is without taking it out as crystals, the aqueous solution of the organic compound represented by the general formula (1) is directly esterified. Since the capacity is large, there is a problem that the volumetric efficiency is low, which is not preferable industrially.

  Then, when the present inventors took out the organic compound represented by General formula (1) as a crystal | crystallization, and examined the improvement of volumetric efficiency, in the evaporation crystallization method and the crystallization method which are shown to patent documents 1-3. The problem of the phenomenon of crystals adhering to the wall of the agitation tank (hereinafter referred to as “scaling”) became clear.

  The present invention has been made in view of the above-mentioned conventional problems, and the object thereof is to crystallize a substance dissolved in water, and at the same time, crystallization without causing scaling. It is to provide a way to do.

  As a result of intensive studies in view of the above problems, the present inventor has made the substance to be crystallized an aqueous solution, and in the process of evaporating water within a temperature range where the evaporation temperature of water and the precipitation temperature of the substance overlap, By evaporating water, particles having at least the surface hydrophilicity and capable of retaining the shape in water coexist with the aqueous solution to crystallize a substance having a desired particle size without causing scaling. The inventors have found out that they can be analyzed, and have completed the present invention.

  That is, the crystallization method of the present invention includes an aqueous solution preparation step for preparing an aqueous solution containing a substance to be crystallized and water, an organic substance that does not dissolve the substance, is not miscible with water, and is azeotropic with water. From the mixed solution preparation step of mixing the solvent and the aqueous solution obtained in the aqueous solution preparation step, and from the mixed solution obtained in the mixed solution preparation step, water and the organic solvent are azeotropically distilled to crystallize the substance. In the crystallization step, water and the organic solvent are co-existed from the mixed solution in the presence of particles having at least a hydrophilic surface and insoluble in water. It is characterized by boiling.

  According to the invention, an aqueous solution preparation step for preparing an aqueous solution containing a substance to be crystallized and water, an organic solvent that does not dissolve the substance, is not miscible with water, and is azeotropic with water, and By including the mixed solution preparation step of mixing the aqueous solution obtained in the aqueous solution preparation step, the water droplets of the aqueous solution of the substance can be made smaller than in the case where the mixed solution preparation step is not included. Moreover, the said substance can be crystallized by including the crystallization process which carries out the azeotropic distillation of water and the said organic solvent from the mixed solution obtained at the said mixed solution preparation process, and crystallizes the said substance. Further, in the crystallization step, water and the organic solvent are azeotropically distilled from the mixed solution in the presence of particles having at least a surface having hydrophilicity and insolubility in water. Since the water adsorbs on the particles, the substance can be made into finer crystals. Further, by performing crystallization of the substance in the presence of the particles, the particle density in the azeotropic distillation tank is increased, so that the crystals of the substance are difficult to approach the wall surface of the azeotropic distillation tank. As a result, the crystallization method of the present invention can prevent scaling after the substance is crystallized. This is presumably because the aqueous solution in which the substance is dissolved adsorbs on the particle surface because the particle surface is hydrophilic and does not adhere to the wall surface of the tank.

  Furthermore, according to the invention, by including the mixed solution preparation step, water droplets of the aqueous solution of the substance can be made smaller than in the case where the aqueous solution of the substance is crystallized without being mixed with an organic solvent. Can do. As a result, in the crystallization method of the present invention, when water and the organic solvent are azeotropically distilled from the mixed solution in the crystallization step, the surface area per unit volume of the substance is increased, so that the reaction yield is increased. The rate can be improved.

  In the crystallization method of the present invention, in the mixed solution preparation step, the aqueous solution obtained in the aqueous solution preparation step is supplied to the organic solvent, and the aqueous solution is micronized in the organic solvent. It is preferable to prepare a mixed solution as

  Thereby, since the aqueous solution is made into a suspension obtained by micronizing the organic solvent, water droplets of the aqueous solution of the substance can be further reduced.

  In the crystallization method of the present invention, in the mixed solution preparing step, the mixed solution is prepared as a suspension by passing the aqueous solution obtained in the aqueous solution preparing step through the porous membrane and supplying the organic solvent. It is preferable to do. Furthermore, in the crystallization method of the present invention, in the mixed solution preparation step, the aqueous solution obtained in the aqueous solution preparation step is allowed to pass through the inner surface of the porous membrane and supplied to the organic solvent on the outer surface of the porous membrane. preferable.

  Thereby, the crystallization method of this invention can suspend the aqueous solution and organic solvent of the said substance using the hole of a porous film.

  In the crystallization method of the present invention, the pore diameter of the porous film is preferably in the range of 0.05 μm or more and 10 μm or less.

  Thereby, the crystallization method of this invention can make the aqueous solution of the said substance minute. As a result, in the crystallization method of the present invention, water is rapidly distilled off. Furthermore, the crystallization method of the present invention can reliably control the crystal grain size of the substance.

  In the crystallization method of the present invention, at least a fluororesin is preferably used as the material of the porous film.

  Thereby, the porous film can be used for suspending various substances due to the heat resistance and chemical resistance of the fluororesin. As a result, the crystallization method of the present invention can be used for crystallization of various substances.

  In the crystallization method of the present invention, in the mixed solution preparation step, the flow rate of the organic solvent is 0.8 to 20 parts by volume with respect to 1 part by volume of the aqueous solution obtained in the aqueous solution preparation step. It is preferable to supply the aqueous solution to an organic solvent.

  Thereby, since the flow rate of the organic solvent is 0.8 volume part or more with respect to 1 volume part of the flow rate of the aqueous solution of the substance, water is rapidly distilled off. On the other hand, since the flow rate of the organic solvent is 20 parts by volume or less with respect to 1 part by volume of the aqueous solution of the substance, the volume efficiency in the crystallization process tends to be excellent.

  In the crystallization method of the present invention, in the crystallization step, water and the organic solvent are preferably azeotropically distilled from the mixed solution in a distiller.

  Thereby, the crystallization method of the present invention facilitates azeotropic distillation when water and the organic solvent are azeotropically distilled from the mixed solution in the crystallization step.

  In the crystallization method of the present invention, the distiller is an azeotropic distillation tank containing the organic solvent and the particles, and the mixed solution in the azeotropic distillation tank is substantially azeotropic with water. It is preferable to azeotropically distill water and the organic solvent from the mixed solution in the azeotropic distillation tank.

  Thereby, the organic solvent in the azeotropic distillation tank is adjusted to a substantially azeotropic temperature with water, so that the substance can be crystallized by azeotropic distillation of water and the organic solvent.

  In the crystallization method of the present invention, in the distiller, water and the organic solvent are azeotropically distilled from the mixed solution while stirring the mixed solution, and the stirring in the distiller is performed by a rotary blade. In addition, the rotational speed of the rotor blade is expressed by the following equation (1):

(Where n represents the number of revolutions required for floating the particles, D represents the diameter of the azeotropic distillation tank, dp represents the diameter of the particles, ρc represents the solution density, and Δρ represents the particle true density and the solution. Η represents the viscosity of the organic solvent, Vp ′ represents the bulk volume of the particle, Vp represents the true volume of the particle, K represents the shape of the azeotropic distillation tank, the shape of the stirring blade, the baffle It represents a constant determined by the presence or absence of.

  Accordingly, water can be surely adsorbed on the particles, so that scaling after the substance is crystallized is reliably prevented. As a result, the crystallization method of the present invention can reliably control the crystal grain size of the substance.

  In the crystallization method of the present invention, the substance is an organic compound that dissolves in water, and its melting point is equal to or higher than the boiling point of water, the boiling point of the organic solvent, and the azeotropic temperature. preferable.

  As a result, the substance does not melt even when the temperature is higher than the boiling point of water, the boiling point of the organic solvent, and the azeotropic temperature, and continues to exist as crystals.

  In the crystallization method of the present invention, the substance is represented by the general formula (1).

(Wherein Q ₁ and Q ₂ each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group, and M represents Li, Na, K, or Ag). It is preferable.

Thereby, the compound obtained by the crystallization method of the present invention can be easily taken out as a crystal despite being a substance that is easily scaled in an azeotropic distillation tank. The organic solvent is at least selected from the group consisting of hydrocarbons having 5 to 12 carbon atoms, halogenated hydrocarbons having 5 to 12 carbon atoms, ketone solvents having 4 to 12 carbon atoms, and ether solvents having 4 to 12 carbon atoms. One organic solvent is preferred.

  Thereby, the organic solvent does not dissolve the substance, is not miscible with water, and azeotropes with water. Therefore, the crystallization method of the present invention can make water droplets of the aqueous solution of the substance smaller. .

  In the crystallization method of the present invention, the particles are preferably at least one particle selected from the group consisting of silica gel, alumina, titania, zeolite, borax, talc, clay, and wood flour.

  As a result, since the particles are easily adsorbed with water, the crystallization method of the present invention can further prevent scaling after the material is crystallized, and can further control the crystal particle size of the material. it can.

  According to the present invention, it is possible to take out a substance dissolved in water as crystals, and to crystallize it while suppressing scaling.

  The following description is based on FIGS. 1 and 2 which are one embodiment of the present invention.

(I) Substances to be crystallized in the present invention, materials used in the present invention, etc. The crystallization method of the present invention comprises an aqueous solution preparation step for preparing an aqueous solution containing a substance to be crystallized and water, and the above substances Obtained in the mixed solution preparation step, and the mixed solution preparation step in which the organic solvent that is not miscible with water and azeotropic with water and the aqueous solution obtained in the aqueous solution preparation step are mixed. A crystallization step of azeotropically distilling water and the organic solvent from the mixed solution to crystallize the substance. In the crystallization step, at least the surface is hydrophilic and insoluble in water. Water and the organic solvent are azeotropically distilled from the mixed solution in the presence of particles having. In the crystallization method of the present invention, in the mixed solution preparation step, the aqueous solution obtained in the aqueous solution preparation step is supplied to the organic solvent, and the aqueous solution is micronized in the organic solvent. It is preferable to prepare a mixed solution as

  In the crystallization method of the present invention, in the crystallization step, water and the organic solvent are preferably azeotropically distilled from the mixed solution in a distiller. In the crystallization method of the present invention, the distiller is an azeotropic distillation tank containing the organic solvent and the particles, and the mixed solution in the azeotropic distillation tank is substantially azeotropic with water. It is preferable to azeotropically distill water and the organic solvent from the mixed solution in the azeotropic distillation tank.

  Here, the term “miniaturization” means that the aqueous solution of a substance to be crystallized has water droplets having a particle diameter of 0.01 μm or more and 1000 μm or less. The azeotropic distillation means that when the boiling point of the mixture containing water and the organic solvent is lower than the boiling points of water and the organic solvent, the water and the organic solvent are distilled at the boiling point of the mixture. An aqueous solution (water droplet) of a substance to be crystallized is mixed with an organic solvent, water is distilled from the aqueous solution together with the organic solvent, and the substance to be crystallized does not dissolve in the organic solvent, so that it can be taken out as crystals. it can.

  Thereby, the obtained crystal has a particle size in the order of 10 μm, more specifically, the particle size is in the range of 1 μm to 1000 μm, preferably 10 μm to 500 μm.

<Crystal>
Crystallization means that a substance to be crystallized is precipitated as crystals. Specifically, for example, a method of performing crystallization by distilling off water by azeotropic distillation while stirring an aqueous solution containing a substance to be crystallized in an azeotropic distillation tank in which particles and an organic solvent described below are present, Examples include a method of mixing the suspension in a thin film continuous evaporator in which an organic solvent adjusted to an azeotropic temperature or higher and particles described below flow.

  The crystallized substance can be taken out using means such as filtration, centrifugation, and drying.

<Substance to be crystallized>
In the crystallization method of the present invention, the substance to be crystallized is usually an organic compound that dissolves in water and has an melting point of 100 ° C. or higher.

  Specifically, it is an organic compound having 2 to 20 carbon atoms, and in the molecule of the compound, an acidic hydrophilic group such as a carboxylic acid group, a sulfonic acid group or a phosphoric acid group, or a basic group such as an amino group. Or a compound containing a hydrophilic group such as a hydroxyl group. Among these, an acidic hydrophilic group is preferable because it is easy to crystallize.

  When the substance to be crystallized is a compound containing an acidic hydrophilic group, it is usually dissolved in water using a cation such as lithium, potassium, sodium or silver as a counter ion. The aqueous solution in which the compound containing a group is dissolved is adjusted to be basic with the cation hydroxide or the like.

  In particular, if the substance to be crystallized is an organic compound represented by the formula (1), the compound obtained by the present crystallization method is a crystal even though it is a substance that can be easily scaled in an azeotropic distillation tank. It is preferable because it can be easily taken out.

Here, Q ₁ and Q ₂ are each independently a fluorine atom or a C 1-6 perfluoroalkyl group, and preferably a fluorine atom.

<Suspension>
The suspension of the present invention means that an aqueous solution containing a substance to be crystallized is dispersed or emulsified in an organic solvent that does not dissolve the substance. In the crystallization method of the present invention, considering the dispersibility of the aqueous solution in the organic solvent, for example, dispersion using a dispersant, emulsification using an emulsifier, dispersion or emulsification using a surfactant, porous Examples thereof include dispersion or emulsification using a membrane, dispersion or emulsification using a material having pores other than the porous membrane, dispersion or emulsification using a spray, and dispersion or emulsification using a homomixer. Among them, dispersion or emulsification using a porous film, dispersion or emulsification using a material with pores other than the porous film, because it can be suspended regardless of what the substance to be crystallized is. Dispersion or emulsification using a spray or dispersion or emulsification using a homomixer is preferred. Further, for the reason that the diameter of the substance in the suspension can be controlled, dispersion or emulsification using a porous membrane is more preferable, and in particular, emulsification, dispersion using a porous material without using a surfactant or Suspension is preferred because the resulting material to be crystallized does not contain such agents.

  In the crystallization method of the present invention, in the mixed solution preparation step, for example, the aqueous solution obtained in the aqueous solution preparation step may be supplied through a porous material in a standing organic solvent, The aqueous solution obtained in the aqueous solution preparation step may be supplied through the porous material in the flowing organic solvent. Especially, it is preferable that the flow rate of the organic solvent is 0.8 to 20 parts by volume with respect to 1 part by volume of the aqueous solution obtained in the aqueous solution preparation step, and the aqueous solution is supplied to the organic solvent. If it is 0.8 part by volume or more, water is preferably distilled off rapidly, and if it is 20 parts by volume or less, it is preferable because volume efficiency in the crystallization process tends to be excellent. Moreover, it is preferable that the flow rate of the organic solvent is 3 parts by volume or more with respect to 1 part by volume of the aqueous solution of the substance because water is rapidly distilled off.

  When a porous membrane is used in the suspension preparation step, the solvent is preferably 1 part by weight or more and 1 part by weight or less of the aqueous solution and less than the azeotropic composition of water and the solvent. In the case of a porous membrane, since the interval between the obtained fine aqueous solutions (water droplets) is small, the suspension can be stabilized by quickly suspending it using many organic solvents of 1 part by weight or more. Is preferable. In addition, if a solvent with a larger amount than the azeotropic composition of water and solvent is used, when water evaporates in the crystallization process, the solvent accumulates in the crystallization container, which requires a large container and lowers volumetric efficiency. To do. Therefore, the amount of the solvent is preferably not more than the azeotropic composition of water and the solvent.

  In the crystallization method of the present invention, a substance to be crystallized is suspended in water to form a suspension, and an organic solvent may be further added to the suspension.

  Suspension (dispersion or emulsification) using a porous membrane is carried out as a suspension by passing the aqueous solution obtained in the aqueous solution preparation step through the porous membrane and supplying it to the organic solvent in the mixed solution preparation step. It is preferable to prepare a mixed solution. That is, it is performed by passing an aqueous solution containing the above substance through the porous membrane. Thereby, a suspension can be prepared. In preparing the suspension, the method and conditions for allowing the mixture of the substance and water to pass through the porous membrane are preferably the continuous passage of the aqueous solution containing the substance through the porous membrane. Further, in the mixed solution preparation step, the aqueous solution obtained in the aqueous solution preparation step is passed through the inner surface of the porous membrane and supplied to the organic solvent on the outer surface of the porous membrane, thereby miniaturizing the substance. Is preferred.

  A porous membrane refers to a membrane having many pores, and the material of the membrane, the area of the membrane, the thickness of the membrane, the strength of the membrane, the number of pores, as long as it allows the mixture of the substance and water to pass through. The diameter of the pores and the like can be appropriately changed depending on the method or conditions for allowing the mixture of the substance and water to pass through the porous membrane.

  For example, the material of the porous film may be an organic film or an inorganic film. Here, the organic film refers to a film using a polymer or the like. An inorganic film refers to a film using an inorganic material such as ceramics. Among them, for the reason of excellent heat resistance and chemical resistance, it is preferable that at least a fluororesin is used in the porous film, and further, it is not affected by almost all organic solvents, acids, and alkalis, that is, From the reason that the corrosion resistance is excellent, polytetrafluoroethylene is more preferably used for the porous film. In particular, when the porous film is immersed in an organic solvent, the porous film is more preferably made of polytetrafluoroethylene having resistance to organic solvents. Thereby, the said porous membrane can be used for suspension of more substances. As a result, the crystallization method of the present invention can be used for crystallization of more substances.

  Further, the shape of the porous film may be, for example, a planar shape, a column shape, a tube shape, or the like. Moreover, it is preferable that the hole diameter of a porous film is 0.05 micrometer-10 micrometers, and it is more preferable that it is 0.1 micrometer-2 micrometers. Further, the pore diameter is preferably 0.05 μm or more, because the liquid passing time tends to be shortened and the pressure necessary for passing water droplets tends to be reduced, and the pore diameter is preferably 10 μm or less. This is preferable because the phenomenon of the crystal scaling to the tank wall tends to be reduced.

<Particle>
Specific examples of the particles having hydrophilicity and insolubility in water include silica gel, alumina, titania, zeolite, borax, talc, clay, wood powder and the like. Among these, silica gel is preferable because it easily adsorbs water.

  The size of the particles is preferably 40 μm or more and 120 μm or less. When it is 40 μm or more, it is preferable because the obtained crystal is miniaturized to 0.01 μm to 1000 μm, which is easy to handle. Moreover, it is preferable for it to be 120 μm or less because the resulting crystals are easily dispersed in the azeotropic distiller, and the resulting crystals are reduced to 0.01 μm to 1000 μm, which is easy to handle.

  The content ratio of the particles is preferably 1% by weight or more and 1000% by weight or less, more preferably 1% by weight or more and 100% by weight or less, and particularly preferably 1% by weight or more and 10% by weight with respect to the crystallization target substance. % Or less. It is preferable that the content ratio of the particles is 1% by weight or more because scaling after the substance is crystallized tends to be prevented. On the other hand, it is preferable that the amount is 1000% by weight or less because the obtained crystal is miniaturized to 0.01 μm to 1000 μm which is easy to handle.

  The particle may be added at the beginning of the reaction crystallization, during the reaction crystallization, or may be added to both of them. Moreover, it is preferable to add before the aqueous solution of the substance to be crystallized is mixed in the azeotropic distillation apparatus.

<Organic solvent>
Examples of organic solvents that do not dissolve the substance to be crystallized, are not miscible with water, and azeotrope with water include, for example, benzene, toluene, xylene, n-heptane, n-hexane, cyclohexane, n-octane, and the like. C 5-12 hydrocarbons; C 5-12 halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride, chloroform, chlorobenzene, dichlorobenzene and trichlorobenzene; 4 carbon atoms such as methyl ethyl ketone and methyl isobutyl ketone -12 ketones; ethers having 4 to 12 carbon atoms such as tetrahydrofuran, diethyl ether, dioxane, methyl cellosolve and the like. Here, “not miscible with water” means not compatible with water.

<Crystal obtained>
In the crystallization method of the present invention, the crystal grain size of the substance can be 0.01 μm or more and 1000 μm or less. Further, the crystallization method of the present invention can crystallize the crystals of the above substances with a high yield and high purity of 99% to 100%. When calculating the yield, the method for calculating the amount of crystals obtained includes, for example, a method for measuring the amount of crystals deposited after the crystallization step, and a concentration of the above substance with respect to water evaporated in the crystallization step. A calculation method or the like may be used.

(II) Crystallization method of the present invention <Crystallization method>
The crystallization method of the present invention comprises an aqueous solution preparation step for preparing an aqueous solution containing a substance to be crystallized and water, an organic solvent that does not dissolve the substance, is not miscible with water, and is azeotropic with water, And the mixed solution preparation step of mixing the aqueous solution obtained in the aqueous solution preparation step, and water and the organic solvent are azeotropically distilled from the mixed solution obtained in the mixed solution preparation step to crystallize the substance. In the crystallization step, azeotropic distillation of water and the organic solvent from the mixed solution in the presence of particles having at least a hydrophilic surface and insoluble in water. It is a method to make it. In the mixed solution preparation step, the aqueous solution obtained in the aqueous solution preparation step is supplied to the organic solvent, and the mixed solution is prepared as a suspension obtained by micronizing the aqueous solution in the organic solvent. preferable.

  In the crystallization method of the present invention, in the crystallization step, water and the organic solvent are preferably azeotropically distilled from the mixed solution in a distiller. In the crystallization method of the present invention, the distiller is an azeotropic distillation tank containing the organic solvent and the particles, and the mixed solution in the azeotropic distillation tank is substantially azeotropic with water. It is preferable to azeotropically distill water and the organic solvent from the mixed solution in the azeotropic distillation tank.

  Examples of the distiller include a reaction tank type azeotropic distillation tank in which the inside of the container can be heated with a heat transfer medium, a thin film continuous evaporator in which a suspension flows on a plate adjusted to an azeotropic temperature or higher, etc. Is mentioned.

  The organic solvent in the distiller and the organic solvent in the suspension preparation step may be the same or different, but are preferably the same species because the solvent can be easily recovered.

  In the crystallization method of the present invention, if the crystallization method is classified into steps, the suspension preparation step and the crystallization step can be classified. Hereinafter, the crystallization method will be described in detail based on the classification of the above steps and the apparatus configuration for carrying out the crystallization method.

<Suspension preparation process>
In the suspension preparation step, if necessary, a dispersant, an emulsifier, and a surfactant are added to one or both of the aqueous solution and the solvent, and the suspension is prepared by porous membrane, stirring, spraying, or the like. .

  For example, the preparation of a suspension using a porous membrane is performed by passing a mixture containing the substance and water, and optionally the organic solvent, through the porous membrane. Among them, a method of preparing a suspension by continuously passing the mixture through a porous membrane is preferable because fine crystals such as a dispersant, an emulsifier, and a surfactant can be obtained.

  The suspension preparation step using a porous membrane is performed by operations such as continuous operation (single pass format), batch concentration operation, diafiltration, feed and bleed, and the like. Here, the continuous operation refers to a form in which a stock solution is continuously supplied by a pump to continuously obtain a retentate (liquid that has not passed through the porous membrane) and a passing liquid (liquid that has passed through the porous membrane). Furthermore, the operation of stopping the retentate side is called a dead end type continuous operation. The batch-type concentration operation refers to a form in which the stock solution is continuously supplied by a pump, the retentate is returned to the stock solution tank, and the passing solution is taken out of the system. Diafiltration is a type in which the stock solution is continuously supplied by a pump, the retentate is returned to the stock solution tank, the passing solution is taken out of the system, and the solvent is added to the stock solution tank. The feed and bleed is a type that involves circulation of the retentate in a continuous operation.

  In addition, for example, the suspension is prepared by stirring by stirring the substance and water, and in some cases, the organic solvent with a stirring device. As a stirring apparatus, a homomixer etc. are mentioned, for example.

  In addition, for example, the suspension is prepared by spraying by spraying an aqueous solution of the above substance and, optionally, a mixture containing the organic solvent.

<Crystal crystallization process>
In the crystallization step, the temperature of the suspension is not less than the temperature at which water boils, and not more than the melting point of the substance, preferably not more than the boiling point of the organic solvent. For example, when the organic solvent is monochlorobenzene, it is usually preferably 110 ° C. or higher and 135 ° C. or lower.

  Azeotropically distilled water and organic solvents are usually condensed by a condenser. If the organic solvent can be separated from water, the organic solvent can be reused.

  The temperature of the suspension may be heated by, for example, a mantle heater, a throwing heater, a hot plate, or the like. Furthermore, the set temperature may be controlled by a sensor or the like.

  In the crystallization method of the present invention, in the crystallization step, it is further preferable to evaporate water from the suspension while stirring the suspension or the organic solvent. In the crystallization method of the present invention, in the distiller, water and the organic solvent are azeotropically distilled from the mixed solution while stirring the mixed solution, and the stirring in the distiller is performed by a rotary blade. In addition, the rotational speed of the rotor blade is expressed by the following equation (1):

(Where n represents the number of revolutions required for floating the particles, D represents the diameter of the azeotropic distillation tank, dp represents the diameter of the particles, ρc represents the solution density, and Δρ represents the particle true density and the solution. Η represents the viscosity of the organic solvent, Vp ′ represents the bulk volume of the particle, Vp represents the true volume of the particle, K represents the shape of the azeotropic distillation tank, the shape of the stirring blade, the baffle It represents a constant determined by the presence or absence of. The rotation speed is usually 3000 rotations / minute or less.

  It is preferable that n is greater than or equal to this value because the particles float uniformly in the distillation tank and scaling tends to be suppressed.

  Here, the true density means a density in which only the volume occupied by the substance itself is a volume for density calculation. The true volume means the volume occupied by the substance itself. The bulk volume refers to the internal volume when a substance of a certain volume is fully filled. Moreover, a baffle means a partition plate.

  In the suspension preparation step, the flow rate of the organic solvent is usually 0.8 to 20 parts by volume, preferably 3 to 10 volumes with respect to 1 part by volume of the aqueous solution of the substance when being supplied to the organic solvent. Part. It is preferable that the flow rate of the organic solvent is 0.8 parts by volume or more because water tends to be rapidly distilled off. Moreover, it is preferable that the flow rate of the organic solvent is 20 parts by volume or less because the volume efficiency in the crystallization process tends to be excellent.

<Apparatus configuration for carrying out the crystallization method>
The apparatus configuration for carrying out the crystallization method of the present invention will be described below with reference to FIGS.

  FIG. 1 is a diagram for explaining an apparatus configuration for performing a crystallization method according to an embodiment of the present invention. As shown in FIG. 1, a crystallization apparatus 1 mainly includes a crystallization tank (azeotropic distillation tank, reaction vessel) 2, an aqueous solution supply container 3, a liquid feed pump 4, a pipe 5, an organic solvent supply container 6, and a liquid feed. A pump 7, a stirring blade (rotary blade) 8, a heat exchanger 9, a liquid separation tank 10, a tank 11 for extracting water, a pipe 12, a porous film 13, and a pipe 14 are provided.

  An aqueous solution containing a substance to be crystallized is discharged from the aqueous solution supply container 3 by the liquid feed pump 4, and is supplied to the pipe 12 by allowing the aqueous solution to pass through the pipe 5 from the inner surface of the porous film 13. At that time, the organic solvent having poor solubility in the substance and water is discharged from the organic solvent supply container 6 by the liquid feed pump 7 and supplied to the outer surface of the porous film 13 in the pipe 12 through the pipe 14. deep. This adjusts the suspension. The suspension is supplied from the pipe 12 to the crystallization tank 2. The crystallization tank 2 is supplied in advance with an organic solvent that is sparingly soluble in the above substances and water.

  And, from the suspension supplied to the crystallization tank 2, at least the surface is hydrophilic and in the presence of particles that are insoluble in water, the temperature is equal to or higher than the boiling temperature of water, and Water and an organic solvent are evaporated under a temperature condition that is equal to or lower than a temperature at which the substance is solidified to crystallize the substance. When stirring the suspension and the organic solvent, the suspension is stirred by the stirring blade 8. Thereafter, the water and the organic solvent evaporated by the heat exchanger 9 are cooled, and the water and the organic solvent are separated by the separation tank 10. Thereafter, water is removed by a tank 11 for extracting water, and the organic solvent is returned to the crystallization tank 2. Thereby, the crystal | crystallization of the said substance can be taken out. The crystals of the substance in the crystallization tank 2 can be taken out using means such as filtration, centrifugation, and drying.

  Moreover, FIG. 2 is a figure explaining the other apparatus structure for performing the crystallization method concerning one Embodiment of this invention. As shown in FIG. 2, the crystallizer 20 is mainly composed of a mixing tank (mixing container) 21, an aqueous solution supply container 22, a liquid feed pump 23, a pipe 24, an organic solvent supply container 25, a liquid feed pump 26, a homomixer ( Stirring blade) 27, liquid feed pump 28, piping 29, piping 30, crystallization tank (azeotropic distillation tank, reaction vessel) 31, stirring blade (rotary blade) 33, heat exchanger 34, liquid separation tank 35, water A tank 36 is provided.

  The aqueous solution containing the substance to be crystallized is discharged from the aqueous solution supply container 22 by the liquid feed pump 23 and supplied to the mixing tank 21 through the pipe 24. At that time, the organic solvent which is hardly soluble in the substance and water is discharged from the organic solvent supply container 25 by the liquid feed pump 26 and supplied to the mixing tank 21 through the pipe 30.

  The mixing tank 21 includes a homomixer (stirring blade) 27, and a suspension can be prepared by stirring the above substance, water, and an organic solvent. The suspension is discharged from the mixing tank 21 by the liquid feed pump 28 and supplied to the crystallization tank 31 through the pipe 29. The crystallization tank 31 is previously supplied with an organic solvent that is hardly soluble in the above substances and water.

  And, from the suspension supplied to the crystallization tank 31, at least the surface is hydrophilic and in the presence of particles that are insoluble in water, the temperature is equal to or higher than the boiling temperature of water, and Water and an organic solvent are evaporated under a temperature condition that is equal to or lower than a temperature at which the substance is solidified to crystallize the substance. When stirring the suspension and the organic solvent, the suspension is stirred by the stirring blade 33. Thereafter, the water and the organic solvent evaporated by the heat exchanger 34 are cooled, and the water and the organic solvent are separated by the liquid separation tank 35. Thereafter, water is removed by a tank 36 for extracting water, and the organic solvent is returned to the crystallization tank 31. Thereby, the crystal | crystallization of the said substance can be taken out. The crystals of the substance in the crystallization tank 31 can be taken out using means such as filtration, centrifugation, and drying.

  In addition, when supplying the suspension to the crystallization tank 31, a method is installed in which the tip of the pipe 29 is always positioned below the liquid surface of the organic solvent or suspension in the crystallization tank 31. It may be used. The suspension is supplied continuously or intermittently, but may be supplied into an organic solvent or suspension in the vicinity of the stirring blade 33. Moreover, when supplying the said suspension below the liquid level of an organic solvent or suspension, you may use a well-known dispersing agent in order to improve the dispersibility in a liquid.

  1 and 2, the crystallization tanks 2 and 31 include those having stirring blades 8 and 33 such as paddle blades, turbine blades, and retreat blades. In addition to the stirring blades 8 and 33, the crystallization tanks 2 and 31 may have baffles. Examples of the baffle include a plate baffle, a finger baffle, a beaver tail baffle, and the like.

  Further, as the pipes 5, 14, 24, 29, and 30, for example, a stainless pipe, a Teflon (registered trademark) pipe (a product name of DuPont), a glass pipe, or the like is used.

  Further, the distance from the pipe 29 to the organic solvent or suspension in the crystallization tank 31 may be 1 m or less from the solvent side tip of the pipe 29 to the liquid surface of the organic solvent or suspension. The pipe 29 may be immersed in the organic solvent or suspension in the crystallization tank 31. Moreover, it is preferable that said distance is 1 m or less, and it is more preferable that it is 0.85 m or less. When the distance is 1 m or less, the micronized aqueous solution is immediately mixed with the organic solvent to give a stable suspension.

  The water is evaporated under reduced pressure, pressure or atmospheric pressure. When water forms an azeotrope with an organic solvent, the boiling temperature of water is azeotropic.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[Example 1]
<Preparation of aqueous solution containing substances to be crystallized>
65 parts by weight of sodium carboxy (difluoro) methanesulfonate as a substance to be crystallized was collected in a container, and 296 parts by weight of water was added to the mixing container to prepare an aqueous solution.

<Crystal removal>
6 parts by weight of silica gel (manufactured by Kanto Chemical Co., Inc.) and 635 parts by weight of monochlorobenzene were added to a glass reaction vessel (cylindrical shape having a bottom half half ellipse) equipped with a stirring blade (three receding blades). Collected and added the aqueous solution. Then, using a heat exchanger for cooling the evaporated water and monochlorobenzene, a separation tank for separating water and monochlorobenzene, and a tank (Daikan) for extracting water, Chlorobenzene was removed, and crystals of sodium carboxy (difluoro) methanesulfonate were taken out.

<Physical properties of crystals>
Thereafter, the grain size and yield of the crystal were measured, and no scaling was observed when the crystal was taken out.

[Example 2]
<Suspension preparation>
From a container containing 35 parts by weight of an aqueous solution containing 6.3 parts by weight of sodium carboxy (difluoro) methanesulfonate represented by the general formula (1), the aqueous solution was placed in a dead end type Teflon (registered trademark). Material is continuously supplied inside the porous film (trade name: “Porefluorocarbon tube”, manufactured by Sumitomo Electric Industries, Ltd.), and 420 parts by weight of monochlorobenzene (manufactured by Kureha) is continuously supplied outside the porous film. The aqueous solution was permeated through the porous membrane to prepare a suspension outside the porous membrane.

<Crystal removal>
0.8 parts by weight of silica gel and 90 parts by weight of monochlorobenzene were placed in a container (having a cylindrical shape with a half semi-elliptic bottom) having a stirrer blade (three receding blades) and made of Hastelloy C22. The above suspension was added. Then, using a heat exchanger for cooling the evaporated water and monochlorobenzene, a separation tank for separating water and monochlorobenzene, and a tank (Daikan) for extracting water, Chlorobenzene was removed, and crystals of sodium carboxy (difluoro) methanesulfonate were taken out.

[Comparative Example 1]
<Preparation of aqueous solution containing substances to be crystallized>
65 parts by weight of sodium carboxy (difluoro) methanesulfonate as a substance to be crystallized was collected in a glass mixing container, and 296 parts by weight of water was added to the mixing container to prepare an aqueous solution.

<Crystal removal>
635 parts by weight of monochlorobenzene was collected in a reaction vessel (a cylindrical shape having a half-elliptical bottom) having a stirring blade (three receding blades) and made of glass, and the above aqueous solution was added thereto. And using a heat exchanger for cooling the evaporated water and monochlorobenzene, a separation tank for separating water and monochlorobenzene, and a tank for extracting water, water and monochlorobenzene are removed, Crystals of sodium carboxy (difluoro) methane sulfonate were taken out.

<Physical properties of crystals>
Thereafter, the grain size and yield of the crystal were measured, and scaling was observed when the crystal was taken out.

  Table 1 summarizes the crystal grain sizes and yields obtained in Example 1, Example 2, and Comparative Example 1, and the presence or absence of scaling. In Example 1, the crystal grain size is 300 to 1000 μm, and in Example 2, the crystal grain size is 1 to 10 μm. In Comparative Example 1, the crystal grain size is 1000 to 10,000 μm, and silica gel is used. By adding, the grain size of the crystal could be reduced. In Example 1, the crystal yield was 50%, and in Example 2, the crystal yield was 70%. In Comparative Example 1, the crystal yield was 25%, and silica gel was added. By doing so, crystals could be obtained in high yield. Furthermore, in Example 1 and Example 2, scaling did not occur, whereas in Comparative Example 1, scaling occurred, and scaling could be suppressed by adding silica gel. In Example 1 and Example 2, the crystals were attached to most silica gel surfaces. Furthermore, in Example 1 and Example 2, after the crystal adhered to the silica gel surface, the crystal was peeled off.

  Thereby, in Example 1, the particle size of the crystal | crystallization of sodium carboxy (difluoro) methanesulfonate was controlled, and it resulted in not causing scaling. In other words, it was revealed that by adding silica gel in the crystallization step, the particle size of the crystal obtained by crystallization is controlled and scaling does not occur.

  In the present invention, a substance having a desired particle size can be crystallized without causing scaling. Therefore, the present invention can be widely applied in the fields of chemicals such as pharmaceuticals, agricultural chemicals, additives, pigments, electronic industrial chemicals, and paints.

It is a top view explaining the apparatus structure for performing the crystallization method concerning one Embodiment of this invention. It is a top view explaining the apparatus structure for performing the crystallization method concerning one Embodiment of this invention.

Explanation of symbols

1 Crystallizer 2 Crystallization tank (azeotropic distillation tank, reaction vessel)
3 Aqueous solution supply container 4 Liquid feed pump 5 Piping 6 Organic solvent supply container 7 Liquid feed pump 8 Stirring blade (rotary blade)
DESCRIPTION OF SYMBOLS 9 Heat exchanger 10 Separation tank 11 Water extraction tank 12 Piping 13 Porous membrane 14 Piping 20 Crystallizer 21 Mixing tank (mixing vessel)
22 Aqueous solution supply container 23 Liquid feed pump 24 Piping 25 Organic solvent supply container 26 Liquid feed pump 27 Homomixer (stirring blade)
28 Liquid feed pump 29 Piping 30 Piping 31 Crystallization tank (azeotropic distillation tank, reaction vessel)
33 Stirring blade (rotary blade)
34 Heat exchanger 35 Separation tank 36 Tank for extracting water

Claims (14)

An aqueous solution preparation step for preparing an aqueous solution containing a substance to be crystallized and water;
An organic solvent that does not dissolve the substance, is not miscible with water, and can be azeotroped with water, and a mixed solution preparation step of mixing the aqueous solution obtained in the aqueous solution preparation step;
From the mixed solution obtained in the mixed solution preparation step, including crystallization step of crystallizing the substance by azeotropic distillation of water and the organic solvent,
In the crystallization step, water and the organic solvent are azeotropically distilled from the mixed solution in the presence of particles having at least a hydrophilic surface and insolubility in water. Analysis method.   In the mixed solution preparation step, the aqueous solution obtained in the aqueous solution preparation step is supplied to the organic solvent, and the mixed solution is prepared as a suspension obtained by micronizing the aqueous solution in the organic solvent. The crystallization method according to claim 1.   The mixed solution preparation step is characterized in that the mixed solution is prepared as a suspension by passing the aqueous solution obtained in the aqueous solution preparation step through a porous membrane and supplying the solution to the organic solvent. The crystallization method as described.   4. The crystal according to claim 3, wherein in the mixed solution preparing step, the aqueous solution obtained in the aqueous solution preparing step is passed through the inner surface of the porous membrane and supplied to the organic solvent on the outer surface of the porous membrane. Analysis method.   The crystallization method according to claim 3 or 4, wherein the pore diameter of the porous membrane is in the range of 0.05 µm or more and 10 µm or less.   The crystallization method according to any one of claims 3 to 5, wherein at least a fluororesin is used as a material of the porous film.   In the mixed solution preparation step, the flow rate of the organic solvent is 0.8 to 20 parts by volume with respect to 1 part by volume of the aqueous solution obtained in the aqueous solution preparation step, and the aqueous solution is supplied to the organic solvent. The crystallization method according to any one of claims 2 to 6, wherein the method is a crystallization method.   In the said crystallization process, water and the said organic solvent are azeotropically distilled from the said mixed solution in a distiller, The crystallization method of any one of Claims 1-7 characterized by the above-mentioned.   The distiller is an azeotropic distillation tank containing the organic solvent and the particles, the mixed solution in the azeotropic distillation tank is adjusted to a substantially azeotropic temperature with water, and in the azeotropic distillation tank The crystallization method according to claim 8, wherein water and the organic solvent are azeotropically distilled from the mixed solution. In the distiller, while stirring the mixed solution, water and the organic solvent are azeotropically distilled from the mixed solution,
The stirring in the distiller is performed by a rotor blade, and the rotational speed of the rotor blade is expressed by the following formula (1)

(Where n represents the number of revolutions required for floating the particles, D represents the diameter of the azeotropic distillation tank, dp represents the diameter of the particles, ρc represents the solution density, and Δρ represents the particle true density and the solution. Η represents the viscosity of the organic solvent, Vp ′ represents the bulk volume of the particle, Vp represents the true volume of the particle, K represents the shape of the azeotropic distillation tank, the shape of the stirring blade, the baffle Represents a constant determined by the presence or absence of
The crystallization method according to claim 8 or 9, wherein the number of rotations is not less than the number of revolutions specified by the formula (1).   The said substance is an organic compound which melt | dissolves in water, Comprising: The melting | fusing point is more than the boiling point of water, the boiling point of the said organic solvent, and the highest temperature of an azeotropic temperature, The any one of Claims 1-10 characterized by the above-mentioned. The crystallization method according to claim 1. The substance is represented by the general formula (1)

(Wherein Q ₁ and Q ₂ each independently represents a fluorine atom or a C 1-6 perfluoroalkyl group, and M represents Li, Na, K, or Ag). The crystallization method according to any one of claims 1 to 11, wherein:   The organic solvent is selected from the group consisting of hydrocarbons having 5 to 12 carbon atoms, halogenated hydrocarbons having 5 to 12 carbon atoms, ketone solvents having 4 to 12 carbon atoms, and ether solvents having 4 to 12 carbon atoms. It is at least 1 sort (s) of organic solvent, The crystallization method of any one of Claims 1-12 characterized by the above-mentioned.   The said particle | grains are at least 1 sort (s) of particle | grains chosen from the group which consists of a silica gel, an alumina, a titania, a zeolite, a borax, a talc, clay, and a wood powder, The any one of Claims 1-13 The crystallization method according to item.

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