JP2002187946A - Solution preparation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution preparation method which dispenses with a crushing work before charging and is not substantially accompanied by the evaporation of a low-boiling-point organic solvent, such as methylene chloride, in dissolving into the solvent, a compound, such as 2,2-di-(4-hydroxyphenyl) propane or 4-tert-butylphenol, which is solid at normal temperature and has a softening point higher than the boiling point of the solvent by at least 30 deg.C. SOLUTION: A single or mixed solvent is mixed with a single or mixed compound in a molten state which is solid at 30 deg.C or lower and has a softening point at least 30 deg.C higher than the boiling point of the solvent. The resultant solution is cooled to the boiling point of the solvent or lower so that boiling under normal pressure does not occur during or after passing through a line mixer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for preparing a raw material for a reaction used in various chemical reactions or a method for preparing a solution of a chemical substance in an organic solvent used for various uses. The present invention relates to a method for preparing reaction raw materials, which is carried out during the production of

[0002]

2. Description of the Related Art Generally, when a chemical reaction is carried out, the reaction system is converted into a solution in order to control the reaction speed, the viscosity of the reaction system, etc. to a desired state, or to exert an extraction effect by using a solvent. Is often done. In addition, solution preparation is often carried out for industrial reasons such as to make it easy to add reaction raw materials or to easily adjust the amount of reaction raw materials to be added. Further, depending on the use of the obtained reactant, it may be necessary to form a solution to adjust physical properties such as viscosity.

[0003] In such a case, when the reaction raw materials and reactants are in a solid state at room temperature, it is common practice to mix a solvent and a solid compound and to dissolve the mixture by stirring if necessary. It is a target. There is also an example of mixing a solvent and a solid compound in a molten state in a tank, but when the melting point of the solid compound exceeds the boiling point of the solvent, equipment for condensing the vapor of the solvent is necessary because boiling of the solvent occurs. When the melting point of the solid compound exceeds the boiling point of the solvent by 30 ° C. or more, equipment for condensing the vapor of the solvent becomes large-scale, which is extremely disadvantageous from an industrial viewpoint.

[0004]

On the other hand, when a solid compound is dissolved in a solvent, the following problems are likely to occur. That is, since the handling is performed not in a molten state but in a solid state, there is a limit in automation of the handling operation, and there is always a problem that it is difficult to reduce the labor burden of an operator. Further, among the compounds which are in a solid state at normal temperature, agglomeration between small pieces occurs during storage in the form of small pieces such as powders, granules or flakes, and often involves a crushing operation before charging. Furthermore, many of the compounds in the form of small pieces exhibit harmful properties 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. In addition, depending on the flash point of the solvent and the value of the explosion limit, it is necessary to install safety measures to prevent work accidents and disasters.

For example, a promising method is to produce a polycarbonate resin by subjecting a dihydric phenol and phosgene to a condensation reaction in the presence of an alkali and a monohydric phenol as a molecular weight regulator. It is necessary to prepare a methylene chloride solution of both or one of dihydric phenol and monohydric phenol in advance. The melting point of 2,2-di- (4-hydroxyphenyl) propane, which is the most frequently used dihydric phenol as a raw material for polycarbonate resin, is 155 ° C., and 4-tertiary, which is also the most frequently used monohydric phenol. Since butylphenol has a melting point of 100 ° C., each has a considerably higher melting point than 40 ° C., which is the boiling point of methylene chloride. The current preparation method is to methylene chloride,
Room temperature 2,2-di- (4-hydroxyphenyl) propane and / or 4-tert-butylphenol were added and dissolved by stirring. This is because methylene chloride evaporates at a relatively low temperature, so that it is not necessary to heat or it is easy to dissolve it with a minimum amount of heating in terms of equipment design.

However, powdery 2,2-di- (4
(Hydroxyphenyl) propane and 4-tert-butylphenol are liable to aggregate during storage, and this phenomenon is particularly remarkable in 4-tert-butylphenol. For this reason, crushing work is often required. In addition, 2,2-di- (4-hydroxyphenyl) propane and 4-tert-butylphenol have corrosive properties on the skin, and the working environment is deteriorated due to generation of dust during crushing work or charging work in methylene chloride. In order to prevent this, effective mixing work improvement has been required.

In order to solve the above problems, a method has been proposed in which a solid compound is brought into contact with a solvent in a molten state instead of being handled at room temperature, that is, in a state of powder, granules or flakes. In order to increase the temperature of the mixed solution and to evaporate the solvent, equipment for condensing the solvent vapor was required. In addition, if the melting temperature of the solid compound is higher than the boiling point of the solvent, large-scale equipment is required to condense the solvent vapor, and extreme care must be taken to prevent the generation of a large amount of solvent vapor at one time. A dissolution operation had to be performed. In particular, when the melting point of the solid compound exceeds the boiling point of the solvent by 30 ° C. or more, the equipment for condensing the vapor of the solvent needs to be extremely large, which is disadvantageous from an industrial viewpoint.

[0008]

Means for Solving the Problems In view of the above problems, the present inventors have conducted intensive studies, and as a result, have found that a low boiling organic solvent such as methylene chloride is 30 ° C. lower than its boiling point.
2,2-di- (4-hydroxyphenyl)
When adding and dissolving a compound that shows a solid state at room temperature, such as propane or 4-tert-butylphenol, crushing work before dosing is unnecessary, and dosing work and dissolving work can be automated. The present inventors have found a dissolving method that does not generate dust associated with the above and does not substantially involve the vaporization of a low-boiling organic solvent such as methylene chloride during the dissolving operation.

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 to omit the conventionally required crushing work before charging. Or, the dusting caused by the charging operation can be eliminated, and the melting operation can be automated by handling in a liquid state. At that time, it is also possible to prevent the vaporization of the organic solvent by supplying the organic solvent together with the organic solvent to a closed line mixer and cooling the organic solvent to a temperature below the boiling point of the organic solvent while passing through the line mixer. This is a solution preparation method.

The present invention will be described in detail as follows. That is, the present invention relates to a single or mixed solvent (A) which shows a solid state at a temperature of 30 ° C. or lower and has a melting point higher than the boiling point of the solvent (A) by 30 ° C. or more. In the operation of mixing one or a mixed compound (B), a compound (B) in a molten state is added to the solvent (A) to prepare a mixed solution of the solvent (A) and the compound (B). Using a mixer, the solvent (A) and the compound (B) are mixed immediately before or in the line mixer.
And the compound (B) are uniformly mixed, and cooled to a temperature lower than the boiling point of the solvent (A) so that boiling at normal pressure does not occur during or after passing through the line mixer to obtain a uniform solution. How to

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 in a molten state by heating.
Is supplied to the inlet of the line mixer 5 by the pumps 3 and 4, respectively. At this 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, but depending on the types of the solvent (A) and the compound (B) to be used, a simple line mixer is used without using a line mixer. You may mix and dissolve in a piping.

Even if the compound (B) in a high temperature state is mixed with the solvent (A) at a temperature close to room temperature, the solvent (A) does not boil because the so-called closed line is used in the example shown in FIG. (B) and is sent to the inlet of the line mixer 5. Since the temperature of the mixed solution is high, the temperature of the mixed solution is cooled by passing the mixed solution through the heat exchanger 7. After a desired mixed solution is obtained by such an operation, the valve 8 is closed,
The liquid may be sent to the next step by opening the valve 9.

As another method, the valve 9 is closed and the valve 8 is opened.
The compound (B) in the molten state is mixed with the solvent (A) little by little and supplied to the inlet of the line mixer 5, and while the mixed solution is repeatedly circulated to the line mixer 5 via the tank 1, The dissolution ratio of the compound (B) was gradually increased, and when the desired dissolution ratio was reached, the supply of the compound (B) was stopped, the valve 8 was closed, the valve 9 was opened, and the mixed solution was supplied from the valve 9 to the next. It can also be sent to the manufacturing process. This method is a particularly effective mixing method for suppressing a temperature rise in a line mixer when the temperature difference between the boiling point of the solvent (A) and the melting point of the compound (B) is large.

Further, in order to continue the above-mentioned mixing method, when the desired concentration is reached, both the valves 8 and 9 are opened, and at the same time, the amount of the solvent corresponding to the supply amount of the compound (B) is adjusted. (A) may be supplied to the tank 1. In addition, the conceptual diagram shown here is an example shown in order to facilitate the description of the present invention.
The specification may be changed as needed.

The solvent (A) in the present invention does not need to be described in a limited manner because it is determined depending on the purpose of the present invention, but among various solvents, the so-called solvent (A) having a boiling point lower than 65 ° C. The effect of the present invention is remarkably exhibited in a low boiling point solvent. 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, a mixed solvent having a boiling point higher than 65 ° C. individually, such as ethyl alcohol and hexane, which shows an azeotropic point lower than 65 ° C. when mixed, may also be used.

Among them, for example, for the production of polycarbonate resin, 2,2-di- (4-hydroxyphenyl)
For the purpose of dissolving propane or 4-tert-butylphenol, methylene chloride is generally used.

The compound (B) which shows a solid state at normal temperature in the present invention need not be described in a limited manner because it is determined depending on the purpose of the present invention. The effect of the present invention is remarkably exhibited in a solid compound having a temperature higher than 95 ° C. Examples of the solid compound having a melting point of 95 ° C. or more include hydrocarbons such as naphthalene and anthracene, in addition to various phenol compounds described below,
Carboxylic acids such as benzoic acid, phthalic acid, isophthalic acid, and adipic acid, or have a softening point of 95 ° or more, though not showing a clear melting point, and have a substantially molten state unless the temperature is 95 ° C or more. Compounds not shown include, for example, polycondensation compounds such as polystyrene, polyamide, polyethylene terephthalate, and 2,2-di- (4-hydroxydiphenylpropane) / epichlorohydrin co-condensed epoxy resin having a molecular weight of 2,000 or more. It is not limited.

For example, in the case of a raw material for a polycarbonate resin, monocyclic dihydric phenols such as hydroquinone, resorcinol and pyrocatechol, 1,4-dihydroxynaphthalene, 1,6-dihydroxynaphthalene,
Dihydroxynaphthalene compounds such as 3-dihydroxynaphthalene and 2,7-dihydroxynaphthalene;
-Hydroxyphenyl) methane, 2,2-di- (4-hydroxyphenyl) propane, 1,1-di- (4-hydroxyphenyl) cyclohexane, 1,1,1,3,
Bisphenols such as 3,3-hexafluoro-2,2-di- (4-hydroxyphenyl) propane; dihydric phenols such as di (hydroxynaphthyl) methane, biphenol, and binaphthol; 4-tert-butylphenol; Secondary butylphenol, 4-tert-amylphenol, 4-tert-octylphenol, 4-cumylphenol, 1-naphthol, 2
Examples thereof include monohydric phenols such as -naphthol, and among them, 2,2-di- (4-hydroxyphenyl) propane and 4-tert-butylphenol are often used. The above compounds may be used alone or in combination.

Next, as the line mixer in the present invention, the compound (B) melted during line mixing is used.
Any line mixer may be used as long as it has a cooling system for removing heat radiated from the device and a pressure-resistant specification when the temperature rises above the boiling point of the solvent (A). Depending on the combination with (B), a simple hollow pipe may be used, but it is desirable to have a filler inside in order to enhance the mixing effect. Examples of the line mixer having the filler include a static mixer (Noritake Co., Ltd.), a static mixing element (Sulzer),
Square mixer (Sakura Seisakusho), Hi-Mixer (Toray), Comax mixer (Komax Systems)
Co., Ltd., Lightning Inliner (Mixing Eq.)
uipment company) and the like, but is not limited thereto. Hereinafter, examples which demonstrate the effects of the present invention will be described. However, these are merely examples, and do not limit the scope of the present invention.

[0020]

(Example 1) A 50-liter tank 1 provided with a stirrer, an inert gas introduction pipe, and a thermometer, and the tank 1
And a circulation pipe for circulating the contents from the lower part to the upper part. A line mixer 5 (N40 type manufactured by Noritake Co., Ltd.) is provided in the middle of the circulation pipe, and a pipe for supplying a molten compound to the inlet of the line mixer 5 is provided. Is established,
An apparatus as shown in FIG. 1 was used, which was provided with a pump 4 and a valve 6 capable of supplying a fixed amount of a molten compound to the pipe, and a heat exchanger 7 at an outlet of a line mixer 5. A 50-liter tank 1 was charged with 30 kg of methylene chloride, and the circulation pipe including the line mixer 5 was filled with methylene chloride. At this time, the valve 8 is open and the valve 9 is closed. The methylene chloride was circulated by the pump 3 at a flow rate of 150 liters per hour while being heated to a liquid temperature of 30 ° C. and stabilized at 30 ° C.

The circulating liquid of methylene chloride is supplied from the pipe of the valve 6 at a flow rate of 10 kg per hour at 120 ° C.
And 7.5 kg of 4-tert-butylphenol heated and kept in a molten state. After passing this mixed solution through the line mixer 5, it is cooled by the heat exchanger 7,
The temperature at the heat exchanger outlet was adjusted to 30 ° C.

A small amount of a sample was collected from the 50-liter tank at any time, and the concentration of 4-tert-butylphenol in the methylene chloride solution was measured by gas chromatography. The supply was stopped.

Example 2 7.5 kg of 4-tert-butylphenol heated to 120 ° C. and kept in a molten state
, Except that the supply amount was 20 kg per hour.
Dissolution was performed in the same manner as in Example 1.

(Embodiment 3) Stirrer, inert gas introduction pipe,
It consists of a 50-liter tank 1 provided with a thermometer, and a circulation pipe for circulating the contents from the lower part to the upper part of the tank 1. A line mixer 5 (N40 type manufactured by Noritake Co., Ltd.) is provided in the middle of the circulation pipe. , A pipe for supplying a molten compound is provided at an inlet of the line mixer 5,
An apparatus as shown in FIG. 1 was used, which was provided with a pump 4 and a valve 6 capable of supplying a fixed amount of a molten compound to the pipe, and a heat exchanger 7 at an outlet of a line mixer 5. A 50-liter tank 1 was charged with 30 kg of methylene chloride, and the circulation pipe including the line mixer 5 was filled with methylene chloride. At this time, the valve 8 is open and the valve 9 is closed. The methylene chloride was circulated by the pump 3 at a flow rate of 150 liters per hour while being heated to a liquid temperature of 30 ° C. and stabilized at 30 ° C.

The circulating liquid of methylene chloride is supplied from the pipe of the valve 6 at a flow rate of 40 kg per hour at 120 ° C.
And 7.5 kg of 4-tert-butylphenol heated and kept in a molten state. After passing this mixed solution through the line mixer 5, it is cooled by the heat exchanger 7,
The temperature at the heat exchanger outlet was adjusted to 30 ° C.

When the 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-tert-butylphenol in the methylene chloride solution is measured by gas chromatography. As a result of measurement by a togram, it was confirmed that the concentration was 20% by weight as set.

REFERENCE EXAMPLE A 50-liter container provided with a stirrer, an inert gas inlet tube, and a thermometer, and a device provided with a nozzle at the top of the container capable of supplying a fixed amount of a molten compound 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. 7.5 kg of 4-tert-butylphenol heated to 120 ° C. and kept in a molten state was supplied from the nozzle at a flow rate of 5 kg per hour.

As a result, the vaporization of methylene chloride was observed immediately after starting the supply of 4-tert-butylphenol, and the vaporization of methylene chloride became remarkable when 4 kg was supplied, and the solution was brought into a boiling state. Abandoned. Due to the supply stop, the desired 20% by weight 4-tert-butylphenol solution could not be obtained.

[0029]

As described above, according to the solution preparation method of the present invention, a compound in a molten state heated to a temperature higher than the boiling point of the solvent by 30 ° C. or more is dissolved in a solvent, and the compound is dissolved in a so-called closed line. Since the mixed solution is prepared, the operation of crushing the solid compound is not required, and no large-scale equipment for condensing the solvent vapor is required, and the automation of the mixing operation is easy.

[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

Continued on the front page (72) Inventor Shigenobu Kida 951-20-102, Wakamatsu-cho, Wakaba-ku, Chiba-shi, Chiba (72) Inventor Yukihiko Ito 5893-1-410, Goi, Ichihara-shi, Chiba F-term (reference) 4G035 AB37 AB54 AC01 AC51 AE13 AE15 4G037 CA02 EA01 4J029 AA09 AB04 BB04A BB05A BB09A BB12A BB13A BC06A BD09A BG08X CA06 CB04A CB05A FB07 HC01 JB023 JB043 JB063 JB123 JB143 JB153 J04153

Claims (7)

[Claims] A single or mixed solvent (A) immediately before or in a line mixer, and 3
A single or mixed molten compound (B) having a solid state at a temperature of 0 ° C. or lower and a melting point higher than the boiling point of the solvent (A) by 30 ° C. or more is mixed, The compound (B) is uniformly dissolved in the solvent (A) during the passage through the mixer, and the solution is kept at or below the boiling point of the solvent (A) during or after passing through the line mixer so that boiling at normal pressure does not occur. A solution preparation method. 2. A new molten compound (B) is continuously supplied to the line mixer while circulating the mixed homogeneous solution to the line mixer, and the compound (B) is gradually added to the solvent (A). The solution preparation method according to claim 1, wherein the dissolution ratio is increased. 3. The solution preparation method according to claim 1, wherein the solvent (A) is a solvent having a boiling point of 65 ° C. or lower. 4. The method according to claim 3, wherein the solvent (A) is methylene chloride. 5. The method according to claim 1, wherein the compound (B) has a melting point of 95 ° C. or higher. 6. The compound (B) is a phenol,
A solution preparation method according to claim 5. 7. The compound (B) is one or more selected from the group consisting of 2,2-di- (4-hydroxyphenyl) propane, 4-tert-butylphenol, and 4-cumylphenol. 7. The solution preparation method according to 6.