JP4592945B2 - Solution preparation method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for preparing a reaction raw material used in various chemical reactions, or a method for preparing an organic solvent solution of a chemical substance used in various applications, and is particularly carried out during the production of a polycarbonate resin. The present invention relates to a method for preparing a reaction raw material.
[0002]
[Prior art]
In general, when a chemical reaction is performed, the reaction system is often made into a solution in order to control the reaction rate, the viscosity of the reaction system, or the like to a desired state or to exhibit an extraction effect by using a solvent. Moreover, in order to make it easy to add a reaction raw material, or for industrial reasons, such as easy to adjust the addition amount of a reaction raw material, solution preparation is often performed. Furthermore, depending on the use of the obtained reaction product, it may be necessary to adjust the physical properties such as viscosity by forming a solution.
[0003]
In such a case, when the reaction raw materials and reactants are in a solid state at room temperature, it is common to mix the solvent and the solid compound and dissolve them by adding an operation such as stirring as necessary. . In some cases, the solvent and the solid compound in the molten state are mixed in the tank. However, when the melting point of the solid compound exceeds the boiling point of the solvent, equipment for condensing the solvent vapor is necessary because boiling of the solvent occurs. In the case where the melting point of the solid compound exceeds the boiling point of the solvent by 30 ° C. or more, the equipment for condensing the solvent vapor becomes large, which is extremely disadvantageous from an industrial viewpoint.
[0004]
[Problems to be solved by the invention]
On the other hand, when the solid compound is dissolved in a solvent, the following problems are likely to occur. That is, since it is handled not in a molten state but in a solid state, there is a limit to the automation of handling work, and there is always a problem that it is difficult to reduce the labor burden on the worker. Further, among compounds showing a solid state at normal temperature, aggregation between small pieces occurs during storage in small pieces such as powder, granules or flakes, and often involves a crushing operation before charging. In addition, some of the compounds in the small piece state exhibit harmful effects such as skin corrosion and inhalation toxicity, such as phenols and organic acids, which may lead to deterioration of the working environment due to dust generated during crushing and charging operations. There are many.
Also, depending on the flash point of the solvent and the value of the explosion limit, it is necessary to install safety measures in order to prevent work accidents and disasters, and industrial disadvantages are unavoidable.
[0005]
For example, a polycarbonate resin is an effective method for producing a divalent phenol and phosgene by subjecting them to a condensation reaction in the presence of an alkali and a monovalent phenol as a molecular weight regulator. It is necessary to prepare in advance a methylene chloride solution of both or one of phenol and monohydric phenol. The melting point of 2,2-di- (4-hydroxyphenyl) propane, which is the most frequently used divalent phenol as a raw material for polycarbonate resin, is 155 ° C, and 4-tertiary is also the most frequently used monovalent phenol. Since the melting point of butylphenol is 100 ° C., all of them have a considerably high melting point as compared with 40 ° C. which is the boiling point of methylene chloride. In the present preparation method, normal temperature 2,2-di- (4-hydroxyphenyl) propane and / or 4-tertiary butylphenol is added to methylene chloride and dissolved by stirring. This is because methylene chloride is vaporized at a relatively low temperature, so that it is not necessary to heat or it is easy to dissolve with a minimum degree of heating in terms of facility design.
[0006]
However, powdered 2,2-di- (4-hydroxyphenyl) propane and 4-tertiary butylphenol tend to aggregate during storage, and the phenomenon is particularly remarkable in 4-tertiary butylphenol. Therefore, the actual situation is that crushing work is often required. In addition, 2,2-di- (4-hydroxyphenyl) propane and 4-tertiary butylphenol are corrosive to the skin, and the working environment deteriorates due to the generation of dust during crushing or charging into methylene chloride. Therefore, effective mixing work improvement has been demanded.
[0007]
In order to solve the above-mentioned problems, instead of handling a solid compound at room temperature, that is, in the form of powder, granules or flakes, a method in which a compound in a molten state is contacted with a solvent is used. Equipment was needed to condense the solvent vapor in order to bring about a temperature rise and to vaporize the solvent. Furthermore, if the melting temperature of the solid compound exceeds the boiling point of the solvent, a large-scale facility is required to condense the solvent vapor, and great care is taken to prevent a large amount of solvent vapor from being generated at one time. It was necessary to perform a melting operation.
In particular, when the melting point of the solid compound exceeds the boiling point of the solvent by 30 ° C. or more, it is necessary to make the equipment for condensing the solvent vapor very large, which is disadvantageous from an industrial viewpoint.
[0008]
[Means for Solving the Problems]
As a result of intensive studies in view of the above problems, the present inventors have found that 2,2-di-, which is higher by 30 ° C. or more than its boiling point, with respect to an organic solvent having a low boiling point such as methylene chloride. When adding and dissolving a compound that shows a solid state at room temperature, such as (4-hydroxyphenyl) propane and 4-tertiary butylphenol, crushing work before charging is unnecessary, and automation of charging and dissolving work is possible. The present inventors have found a dissolution method that is possible, does not generate dust accompanying the charging operation, and does not substantially vaporize a low boiling organic solvent such as methylene chloride during the melting operation.
[0009]
That is, by supplying the solid compound (B) having a melting point equal to or higher than the boiling point of the solvent (A) to the melting equipment in a molten state, it is possible not only to eliminate the crushing work that has been conventionally required but also to add It is possible to eliminate the generation of dust accompanying the work input work, and it is possible to automate the melting work by handling in the liquid state. At that time, it is also possible to prevent vaporization of the organic solvent by supplying it together with the organic solvent to the sealed line mixer and cooling it to below the boiling point of the organic solvent while passing through the line mixer. This is a solution preparation method.
[0010]
The present invention is described in detail as follows. That is, the present invention is one or more selected from the group consisting of a solvent (A) that is methylene chloride , 2,2-di- (4-hydroxyphenyl) propane, 4-tertiarybutylphenol, and 4-cumylphenol. In the work of mixing the compound (B), a line mixer was used to prepare the mixed solution of the solvent (A) and the compound (B) by adding the compound (B) in the molten state to the solvent (A). The solvent (A) and the compound (B) are mixed immediately before the line mixer or in the line mixer, and the solvent (A) and the compound (B) are uniformly mixed while passing through the line mixer. It is a method characterized in that after passing through the mixer, the solution is cooled to below the boiling point of the solvent (A) so that boiling at normal pressure does not occur to obtain a uniform solution.
[0011]
Hereinafter, the present invention will be described in more detail with reference to the drawings.
In the conceptual diagram shown in FIG. 1, the solvent (A) in the tank 1 and the compound (B) in the tank 2 that is heated and melted are supplied to the inlet of the line mixer 5 by the pumps 3 and 4, respectively. . At that time, the supply ratio of the solvent (A) to the compound (B) may be set so as to be a desired dissolution ratio of the mixed solution to be obtained. Further, a valve 6 is provided to supply the compound (B) in a molten state to the inlet of the line mixer 5 after the solvent (A) is circulated in the piping system.
In this conceptual diagram, it is particularly preferable to use a line mixer for efficient dissolution. However, depending on the type of the solvent (A) and the compound (B) to be used, it is not necessary to use a line mixer. You may mix and dissolve in piping.
[0012]
Even if the high temperature compound (B) is mixed with the solvent (A) at a temperature close to normal temperature, the solvent (A) does not boil in the example shown in the figure because it is a so-called closed line. And sent to the inlet of the line mixer 5. Since this mixed solution is in a high temperature state, the temperature of the mixed solution is cooled by passing it through the heat exchanger 7. After the desired mixed solution is obtained by such an operation, the valve 8 is closed, the valve 9 is opened, and the solution may be fed to the next step.
[0013]
As another method, in the state where the valve 9 is closed and the valve 8 is opened in the figure, the molten compound (B) is mixed little by little with the solvent (A) by the valve 6 and the line mixer 5 is mixed. The mixture solution is repeatedly circulated through the tank 1 to the line mixer 5 while gradually increasing the dissolution ratio of the compound (B) in the mixed solution, and when the desired dissolution ratio is reached. The supply of the compound (B) is stopped, the valve 8 is closed, the valve 9 is opened, and the mixed solution can be sent from the valve 9 to the next manufacturing process. This method is a particularly effective mixing method for suppressing the temperature rise in the line mixer when the temperature difference between the boiling point of the solvent (A) and the melting point of the compound (B) is large.
[0014]
In order to continue the above mixing method, both the valve 8 and the valve 9 are opened when the desired concentration is reached, and at the same time, the solvent (A) in an amount corresponding to the supply amount of the compound (B). May be supplied to the tank 1.
In addition, the conceptual diagram shown here is an example shown for facilitating the description of the present invention, and specification changes as necessary, such as setting of valves and increase / decrease of line piping, may be included.
[0015]
The solvent (A) in the present invention does not need to be described in a limited manner because it is determined by what purpose the present invention is used. Among various solvents, a so-called low boiling point solvent having a boiling point lower than 65 ° C. The effect of the present invention is remarkably exhibited. Examples of the solvent having a boiling point of 65 ° C. or lower include methylene chloride, acetone, tetrahydrofuran, dimethyl ether, pentane, methyl alcohol, and the like, but are not limited thereto, and may be a mixed solvent thereof.
Furthermore, the solvent which has an azeotropic point lower than 65 degreeC by mixing with the solvent which has individual boiling point exceeding 65 degreeC, such as ethyl alcohol and hexane, is mentioned, for example.
[0016]
Among them, for example, methylene chloride is generally used for the purpose of dissolving 2,2-di- (4-hydroxyphenyl) propane and 4-tertiary butylphenol for the production of polycarbonate resin.
[0017]
The compound (B) which shows a solid state at room temperature in the present invention is not necessarily limited to be described because it depends on what purpose the present invention is used, but among various solid compounds, the melting point is 95 °. The effect of the present invention remarkably appears in a solid compound higher than C. Solid compounds having a melting point of 95 ° C. or more include various phenolic compounds described later, hydrocarbons such as naphthalene and anthracene, carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, and adipic acid, Although it does not show a melting point, it has a softening point of 95 ° or more and does not show a molten state unless it is at a temperature of 95 ° C. or more, such as polystyrene, polyamide, polyethylene terephthalate, 2,2 having a molecular weight of 2000 or more. Examples thereof include polycondensation compounds such as -di- (4-hydroxydiphenylpropane) / epichlorohydrin co-condensation type epoxy resin, but are not limited thereto.
[0018]
For example, in the case of a polycarbonate resin raw material, monocyclic dihydric phenols such as hydroquinone, resorcinol and pyrocatechol, 1,4-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,7 -Dihydroxynaphthalene compounds such as dihydroxynaphthalene, di- (4-hydroxyphenyl) methane, 2,2-di- (4-hydroxyphenyl) propane, 1,1-di- (4-hydroxyphenyl) cyclohexane, 1,1 , 1,3,3,3-hexafluoro-2,2-di- (4-hydroxyphenyl) propane and other bisphenols, di (hydroxynaphthyl) methane, biphenol, binaphthol and other dihydric phenols, Libutylbutyl, 4-secondary butylphenol Examples include monohydric phenols such as diol, 4-tertiary amylphenol, 4-tertiary octylphenol, 4-cumylphenol, 1-naphthol, and 2-naphthol. Among them, 2,2-di- (4-hydroxy Phenyl) propane and 4-tertiary butylphenol are often used.
The above compounds may be used alone or in combination.
[0019]
Next, as the line mixer in the present invention, the temperature rose above the boiling point of the cooling equipment for removing heat radiated from the compound (B) melted during the line mixing and the solvent (A). Any line mixer may be used as long as it has the pressure resistance specifications, and depending on the combination of the solvent (A) and the compound (B), it may be a simple hollow pipe, but in order to enhance the mixing effect. It is desirable to have a filling inside. As a line mixer having a filler, a static mixer (Noritake Company Limited), a static mixing element (Sulzer), a square mixer (Sakai Seisakusho), a Hi-Mixer (Toray), a Comax mixer (Komax Systems), a lightning -Inliner (Mixing Equipment) etc. are mentioned, However, it is not limited to them.
Examples of demonstrating the effects of the present invention will be given below, but these are only examples and do not limit the scope of the present invention.
[0020]
【Example】
Example 1
It consists of a 50 liter tank 1 equipped with a stirrer, an inert gas introduction pipe and a thermometer, and a circulation pipe that circulates the contents from the lower part to the upper part of the tank 1, and a line mixer 5 (Noritake Company) in the middle of the circulation pipe Limited type N40 type), a pipe for supplying the molten compound to the inlet of the line mixer 5, a pump 4 and a valve 6 capable of supplying the molten compound quantitatively to the pipe, and an outlet of the line mixer 5 An apparatus as shown in FIG. 1 equipped with a heat exchanger 7 was used. A 50-liter tank 1 was charged with 30 kg of methylene chloride, and the circulation piping including the line mixer 5 was filled with methylene chloride. At this time, the valve 8 is open and the valve 9 is closed.
While this methylene chloride was circulated by the pump 3 so as to have a flow rate of 150 liters per hour, the liquid temperature was increased to 30 ° C. and stabilized at 30 ° C.
[0021]
7.5 ml of 4-tertiary butylphenol which was heated to 120 ° C. and kept in a molten state was supplied to the circulating liquid of methylene chloride from the pipe of the valve 6 at a flow rate of 10 kg per hour. The mixed solution was allowed to pass through the line mixer 5 and then cooled by the heat exchanger 7 so that the temperature at the outlet of the heat exchanger was adjusted to 30 ° C.
[0022]
Collect a small amount of sample from a 50 liter tank at any time, measure the concentration of 4-tertiary butylphenol in the methylene chloride solution using a gas chromatogram, and stop supplying 4-tertiary butylphenol when the concentration reaches 20% by weight. did.
[0023]
(Example 2)
Dissolution was performed in the same manner as in Example 1 except that 7.5 kg of 4-tertiary butylphenol maintained at a molten state by heating to 120 ° C. was changed to a flow rate of 20 kg per hour.
[0024]
(Example 3)
It consists of a 50 liter tank 1 equipped with a stirrer, an inert gas introduction pipe and a thermometer, and a circulation pipe that circulates the contents from the lower part to the upper part of the tank 1, and a line mixer 5 (Noritake Company) in the middle of the circulation pipe Limited type N40 type), a pipe for supplying the molten compound to the inlet of the line mixer 5, a pump 4 and a valve 6 capable of supplying the molten compound quantitatively to the pipe, and an outlet of the line mixer 5 An apparatus as shown in FIG. 1 equipped with a heat exchanger 7 was used. A 50-liter tank 1 was charged with 30 kg of methylene chloride, and the circulation piping including the line mixer 5 was filled with methylene chloride. At this time, the valve 8 is open and the valve 9 is closed.
While this methylene chloride was circulated by the pump 3 at a flow rate of 150 liters per hour, the liquid temperature was increased to 30 ° C. and stabilized at 30 ° C.
[0025]
To this circulating liquid of methylene chloride, 7.5 kg of 4-tertiary butylphenol kept at a molten state by heating to 120 ° C. was supplied from the piping of the valve 6 at a flow rate of 40 kg per hour. The mixed solution was allowed to pass through the line mixer 5 and then cooled by the heat exchanger 7 so that the temperature at the outlet of the heat exchanger was adjusted to 30 ° C.
[0026]
When this mixed solution reaches the branch point between the valve 8 and the valve 9, the valve 8 is closed and the valve 9 is opened, a sample is taken, and the concentration of 4-tertiary butylphenol in the methylene chloride solution is measured by a gas chromatogram. As a result, it was confirmed that the concentration was 20% by weight as set.
[0027]
(Reference example)
A 50 liter container provided with a stirrer, an inert gas introduction tube, and a thermometer, and an apparatus provided with a nozzle capable of quantitatively supplying the molten compound at the top of the container were used. A 50 liter container was charged with 30 kg of methylene chloride, heated to a liquid temperature of 30 ° C., and stabilized at 30 ° C.
From this nozzle, 7.5 kg of 4-tertiary butylphenol heated to 120 ° C. and kept in a molten state was supplied at a flow rate of 5 kg per hour.
[0028]
As a result, the vaporization of methylene chloride was recognized immediately after the start of the supply of 4-tertiary butylphenol, and when 4 kg was supplied, the vaporization of methylene chloride became significant and the solution was in a boiling state. The desired 20 wt% 4-tertiary butylphenol solution could not be obtained by stopping the supply.
[0029]
【The invention's effect】
As described above, according to the solution preparation method of the present invention, a mixed solution is prepared in a so-called closed line by dissolving a molten compound heated to a temperature higher by 30 ° C. or more than the boiling point of the solvent in the solvent. Therefore, the crushing operation of the solid compound is unnecessary, and no large-scale solvent vapor condensing facility is required, and the mixing operation can be automated easily.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing an embodiment of the present invention.
[Explanation of symbols]
1 Tank 2 Tank 3 Pump 4 Pump 5 Line mixer 6 Valve 7 Heat exchanger 8 Valve 9 Valve

Claims (2)

Immediately before or in the line mixer , from the solvent (A) which is methylene chloride , and 2,2-di- (4-hydroxyphenyl) propane, 4-tertiarybutylphenol, 4-cumylphenol in the molten state One or more compounds (B) selected from the group consisting of the above are mixed, and the compound (B) is uniformly dissolved in the solvent (A) while passing through the line mixer. A method for preparing a solution, wherein the solution is cooled to the boiling point of the solvent (A) or less so that boiling under pressure does not occur. A request to continuously supply a new molten compound (B) to the line mixer while circulating the homogeneous solution after mixing to the line mixer, and gradually increase the dissolution ratio of the compound (B) in the solvent (A). Item 2. A method for preparing a solution according to Item 1.

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