JP2006199767A - Method for producing radically polymerized polymer and microreactor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for efficiently and smoothly producing a radically polymerized polymer of narrow molecular weight distribution in a short time by radical polymerization of a radically polymerizable monomer, and to provide a microreactor that is manufacturable easily. <P>SOLUTION: The method for producing the radically polymerized polymer comprises the following process: A radical polymerization initiator and a radically polymerizable monomer are introduced into reaction tubes each ≤2 mm in inner diameter with the sectional area enlarged stepwise in the reaction liquid flow direction and a polymerization reaction is conducted in a flow type in a homogeneous liquid state in the reaction tubes. The microreactor includes a jacket through which a temperature-controlling fluid can be made to flow and the plurality of reaction tubes arranged in parallel in the jacket each ≤2 mm in inner diameter with the sectional area enlarged stepwise in the reaction liquid flow direction. In this microreactor, by making the temperature-controlling fluid flow through the jacket, the reaction temperatures in the plurality of reaction tubes can be controlled. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a radical polymer and a fine chemical reaction apparatus. More specifically, the present invention performs polymerization of a radical polymerizable monomer in a flow mode in a reaction tube having an inner diameter of 2 mm or less and a cross-sectional area gradually expanding in the flow direction of the reaction solution. , A method for efficiently and smoothly producing a radical polymer with a narrow molecular weight distribution in a short time, and a fine chemical reaction apparatus that can be manufactured without using advanced processing techniques using easily available members. is there.

Recently, interest in microreactors has increased greatly. This microreactor generally refers to a device that performs a reaction in a microchannel having an internal structure of about 1 μm to 1 mm, and is expected to have a great potential to change the chemical industry.
From the organic synthesis surface, the microreactor can, for example, (1) be synthesized in a minute amount, (2) have a large surface area per unit volume (flow rate), and (3) temperature control is extremely easy. (4) Efficient reaction at the interface, (5) Reduction of time, cost, and environmental load, (6) Reaction in a sealed system is possible, so toxic and dangerous compounds are safe (7) Contamination protection by small scale, closed system is possible. (8) Utilization of laminar flow peculiar to microchannel makes it applicable to efficient mixing, product separation and purification. It has the characteristics such as.

In industrial applications, it is also possible to increase the production volume by (a) increasing the number without changing the size of the microchannel (numbering up) (conventional experiment). (This eliminates the intermediate trial steps required when transferring the results obtained in the laboratory to the factory.) (B) It is possible to start production early at low cost. ) It is possible to quickly transfer the experimental results to production. In addition, (d) there is an advantage that a plant for industrial production can be small.
Examples of the chemical reaction using such a microreactor include a method for performing a chemical reaction (for example, see Patent Document 1), production of aldols using a microstructured reaction system (for example, see Patent Document 2), stationary Nitration in a micro-mixer (for example, see Patent Document 3), a method for producing arylboron and alkylboron compounds in a microreactor (for example, see Patent Document 4), and the like are disclosed.

As for the polymerization reaction, for example, an ethylene polymerization reaction in a pressurized system using a metallocene catalyst under a laminar flow condition in a flow channel having a diameter of 1.27 mm has been reported (for example, Non-Patent Document 1). reference). However, this reaction is a coordination polymerization using a metallocene catalyst, and is a radically different technique from the radical polymerization according to the present invention. Furthermore, the radical polymerizable monomer and the polymerization initiator are mixed by a micromixer that mixes them using a fine flow path, and then polymerization is performed to suppress the generation of high molecular weight components in the resulting polymer. A method for producing a radical polymer that avoids formation of a precipitate in a tubular polymerization reactor is disclosed (see, for example, Patent Document 5). However, in this technique, a monomer and a polymerization initiator are mixed in a fine space, and a tubular reactor having a diameter of the order of cm is used as a reactor for performing a polymerization reaction.
Radical polymerization is an important technique widely used in industry as a means for producing various polymers because it can polymerize an extremely large number of monomers. However, in this radical polymerization, large reaction heat is generated at the time of polymerization. Therefore, regardless of whether the reaction method is a batch type or a continuous type, the reaction heat is slowly removed under mild reaction conditions to remove the reaction heat. It is usually performed over time, and there is a problem that production efficiency is poor. In addition, in the conventional polymerization methods, the polymerization temperature in the reaction field tends to be non-uniform due to the heat of reaction, and in the case of a continuous type, the reaction solution is unlikely to become a laminar flow. There is also a problem that a difference occurs, and as a result, the obtained polymer tends to be a mixture of polymers having various molecular weights.

In the radical polymerization, the inventors of the present invention can perform high-efficiency temperature control and obtain a polymer with a narrow molecular weight distribution by performing a polymerization reaction under laminar flow conditions in a flow channel having a diameter of 1 mm and 2 mm, and It has been found that the smaller the inner diameter of the flow path, the narrower the molecular weight distribution. However, reducing the inner diameter of the flow path causes an increase in pressure loss and a risk of blockage of the flow path.
In the production of micro chemical reactors (microreactors), advanced processing techniques such as photolithography, etching, and precision machining are generally required for the production of microchannels. Therefore, chemical reactions using microreactors are not possible. It was difficult to carry out simply.

JP-T-2001-521816 JP 2002-155007 A Special table 2003-506340 gazette Japanese Patent Laid-Open No. 2003-128677 Japanese translation of PCT publication No. 2002-512272 “Anal. Chem.”, 74, 3112 (2002)

  Under such circumstances, the present invention provides a method for efficiently and smoothly producing a radical polymer having a narrow molecular weight distribution in a short time in radical polymerization of a radical polymerizable monomer using a fine chemical reactor, and an easy It is an object of the present invention to provide a fine chemical reaction apparatus that can be manufactured without using a high-level processing technique by using a member that can be obtained.

  As a result of intensive research to achieve the above object, the present inventors, as a reactor, are fine reaction tubes having a diameter equal to or less than a certain value, and the cross-sectional area is expanded stepwise in the reaction liquid flow direction. By using a reaction tube, the heat exchange efficiency is extremely high, temperature control is easy, the flow is dominated by laminar flow, the residence time can be strictly controlled, the pressure loss increases and the flow path In a jacket capable of obtaining a radical polymer having a distribution state of a desired molecular weight in a short time and without causing a risk of blockage of the water, and a jacket capable of circulating a temperature control fluid, It has been found that an apparatus in which fine reaction tubes are arranged in parallel can be adapted to its purpose as a fine chemical reaction apparatus. The present invention has been completed based on such findings.

That is, the present invention
(1) A radical polymerization initiator and a radical polymerizable monomer are introduced into a reaction tube having an inner diameter of 2 mm or less and a cross-sectional area gradually expanding in the reaction solution flow direction. A method for producing a radical polymer, characterized in that a polymerization reaction is carried out in a liquid state by a flow mode;
(2) The method for producing a radical polymer according to (1) above, wherein the radical polymerization initiator and the radical polymerizable monomer are mixed before being introduced into the reaction tube and introduced into the reaction tube,
(3) The method for producing a radical polymer according to (1) or (2), wherein the inner diameter of the reaction tube is 1 mm or less,
(4) A jacket capable of circulating a temperature control fluid, and a plurality of reaction tubes which are arranged in parallel in the jacket and have an inner diameter of 2 mm or less and whose cross-sectional area gradually expands in the reaction liquid flowing direction. A fine chemical reaction apparatus capable of controlling the temperature of the reaction in the plurality of reaction tubes by circulating a temperature control fluid through the jacket,
(5) The fine chemical reaction device according to (4) above, wherein the jacket body and the reaction tube portion are detachable.
Is to provide.

According to the present invention, the polymerization of the radical polymerizable monomer is carried out in a flow mode using a fine reaction tube having an inner diameter of 2 mm or less whose cross-sectional area gradually increases in the flow direction of the reaction solution. Since the inner diameter of the reaction tube is small at the beginning of the reaction with a large polymerization exotherm, the efficiency of heat exchange is extremely high, accurate temperature control is easy, and the cross-sectional area of the reaction tube is reduced after the middle of the reaction when the reaction volume decreases. Therefore, a radical polymer with a narrow molecular weight distribution can be efficiently produced without accompanying risks such as an increase in pressure loss and blockage of the flow path.
Further, according to the present invention, it is possible to provide a fine chemical reaction apparatus that can be manufactured using a member that can be easily obtained without requiring an advanced processing technique.

  In the method for producing a radical polymer of the present invention, a reactor is a fine reaction tube having an inner diameter of 2 mm or less, preferably 1 mm or less, more preferably 10 to 500 μm, and its cross-sectional area is stepwise in the reaction solution flow direction. A microreactor that is expanded to Although there is no restriction | limiting in particular about the length of this reactor, Usually, 0.01-100m, Preferably it is 0.05-50m, More preferably, it is the range of 0.1-10m. In addition, the fact that the cross-sectional area of the reaction tube gradually increases in the reaction liquid flow direction has at least a smaller starting portion of the cross-sectional area and a larger end portion of the cross-sectional area, and is smaller in the middle than the previous portion. A reaction tube that does not have a cross-sectional area.

In the present invention, a radical polymerization initiator and a radical polymerizable monomer are introduced into the fine reaction tube, and a polymerization reaction is carried out in a uniform liquid state in the reaction tube in a flow mode.
The raw material radical polymerizable monomer is not particularly limited as long as it is a radical polymerizable monomer, and various monomers can be used. Examples of the monomer capable of radical polymerization include olefins such as ethylene, propylene, and isobutylene; unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid; and unsaturated monomers such as maleic acid, fumaric acid, maleic anhydride, and itaconic acid. Saturated polycarboxylic acids and acid anhydrides; methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, 2-hydroxyethyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid (Meth) acrylic acid esters such as butyl, 2-ethylhexyl methacrylate, dodecyl methacrylate, 2-hydroxyethyl methacrylate; dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl acrylate hydrochloride, methacrylic acid The Dialkylaminoalkyl (meth) acrylates and addition salts thereof such as tilaminoethyl hydrochloride, dimethylaminoethyl acrylate p-toluenesulfonate, dimethylaminoethyl methacrylate p-toluenesulfonate; acrylamide, methacrylamide, N Acrylamide monomers such as methylolacrylamide, N, N-dimethylacrylamide, acrylamide-2-methylpropanesulfonic acid and its sodium salt; styrene, α-methylstyrene, p-styrenesulfonic acid and its sodium salt, potassium salt Styrenic monomers such as allylamine and addition salts thereof, vinyl acetate, acrylonitrile, methacrylonitrile, N-vinylpyrrolidone, further vinyl fluoride, vinylidene fluoride, tetrafluoroethylene And oil-soluble or water-soluble monomers such as fluorine-containing monomers. These monomers may be used individually by 1 type, and may be used in combination of 2 or more type.

In the present invention, a polymerization solvent can be used as desired in order to carry out the polymerization reaction in a uniform liquid state in the fine reaction tube. This polymerization solvent is appropriately selected from aqueous solvents and various organic solvents according to the type of radical polymerizable monomer used. As an aqueous solvent, water or water and an organic solvent miscible with it (organic acids such as formic acid, acetic acid and propionic acid, esters such as methyl acetate and ethyl acetate; acetone, methyl ethyl ketone, diethyl ketone and methyl isobutyl ketone) Ketones; alcohols such as methanol, ethanol and propanol; dimethyl sulfoxide, dimethylformamide and the like).
On the other hand, examples of the organic solvent include water-miscible organic solvents; other esters, ketones, alcohols; ethers such as diethyl ether and tetrahydrofuran; aliphatics and fats such as hexane, cyclohexane, heptane, and octane. Cyclic hydrocarbons; aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; chlorinated hydrocarbons such as methylene chloride, dichloroethane, chloroform, carbon tetrachloride, chlorobenzene and dichlorobenzene. These organic solvents may be used individually by 1 type, and may be used in combination of 2 or more types.

The radical polymerization initiator is not particularly limited and is appropriately selected from known radical polymerization initiators conventionally used in radical polymerization according to the type of the radical polymerizable monomer or polymerization solvent used as a raw material. Can be used. Examples of such radical polymerization initiators include organic peroxides, azo compounds, disulfide compounds, redox initiators, persulfates, and the like. In general, when the polymerization solvent is an aqueous medium, water-soluble organic peroxides, water-soluble azo compounds, redox initiators, persulfates, and the like are preferably used, and the polymerization solvent is an organic solvent. For this, oil-soluble organic peroxides and oil-soluble azo compounds are preferably used.
Examples of the water-soluble organic peroxide include t-butyl hydroperoxide, cumene hydroperoxide, diisopropylbenzene hydroperoxide, p-menthane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1 , 3,3-tetramethyl hydroperoxide and the like. Examples of water-soluble azo compounds include 2,2′-diamidinyl-2,2′-azopropane monohydrochloride, 2,2′-diamidinyl-2,2′-azobutane monohydrochloride, 2,2 Examples include '-diamidinyl-2,2'-azopentane monohydrochloride and 2,2'-azobis (2-methyl-4-diethylamino) butyronitrile hydrochloride.

Examples of redox initiators include a combination of hydrogen peroxide and a reducing agent. In this case, as the reducing agent, divalent iron ions, copper ions, zinc ions, cobalt ions, vanadium ions and other metal ions, ascorbic acid, reducing sugars and the like are used. Examples of the persulfate include ammonium persulfate and potassium persulfate.
One of these water-soluble radical polymerization initiators may be used alone, or two or more thereof may be used in combination.
On the other hand, examples of oil-soluble organic peroxides include diacyl peroxides such as dibenzoyl peroxide, di-3,5,5-trimethylhexanoyl peroxide, and dilauroyl peroxide, diisopropyl peroxydicarbonate, and di-sec-butylperoxy. Peroxydicarbonates such as dicarbonate and di-2-ethylhexylperoxydicarbonate; peroxyesters such as t-butylperoxypivalate and t-butylperoxyneodecanoate; or acetylcyclohexylsulfonyl peroxide and disuccinic acid peroxide Is mentioned. Examples of oil-soluble azo compounds include 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis (2,4-dimethylvalero). Nitrile) and the like. These oil-soluble radical polymerization initiators may be used alone or in combination of two or more.

In the present invention, the amount of the radical polymerization initiator used is appropriately selected according to the kind of the radical polymerizable monomer and radical polymerization initiator used as the raw material used, the desired molecular weight of the polymer to be obtained, etc. It is selected in the range of 0.0001 to 0.5 parts by mass, preferably 0.001 to 0.1 parts by mass with respect to 100 parts by mass of the radical polymerizable monomer.
In the present invention, a chain transfer agent can be used as necessary. The chain transfer agent is not particularly limited as long as it does not inhibit the polymerization reaction and can adjust the molecular weight of the polymer to be produced. Mercaptans, α-methylstyrene dimer, etc. are preferably used. It is done. Here, as mercaptans, for example, 1-butanethiol, 2-butanethiol, 1-octanethiol, 1-dodecanethiol, 2-methyl-2-heptanethiol, 2-methyl-2-undecanethiol, 2- Examples thereof include methyl-2-propanethiol, mercaptoacetic acid and its ester, 3-mercaptopropionic acid and its ester, 2-mercaptoethanol and its ester. These chain transfer agents may be used individually by 1 type, and may be used in combination of 2 or more type.

The present invention is characterized in that radical polymerization is performed using a fine reaction tube having an inner diameter of 2 mm or less and a cross-sectional area gradually expanding in the reaction solution flow direction as one uniform reaction zone. In other words, the reaction tube has a large reaction amount and a large polymerization exotherm, and the inner diameter of the reaction tube is small. Therefore, the efficiency of heat exchange is extremely high and temperature control is easy. ) And the temperature of the entire reaction zone can be kept uniform, so that a radical polymer having a narrow molecular weight distribution can be obtained. In addition, the cross-sectional area of the reaction tube gradually increases after the middle of the reaction when the amount of polymer increases and the viscosity of the reaction solution is large, which may involve risks such as increased pressure loss and blockage of the flow path. Absent.
As a mode of introduction of the radical polymerization initiator and the radical polymerizable monomer into the fine reaction tube, the radical polymerization initiator and the radical polymerizable monomer are mixed immediately before introduction into the fine reaction tube, It is preferable to introduce into a fine reaction tube. As a raw material liquid, a radical polymerization initiator, a radical polymerizable monomer, and a polymerization medium and a chain transfer agent used as necessary can be mixed in advance and introduced into a fine reaction tube. A part of the monomer may undergo a polymerization reaction to form a polymer, and as a result, a broad peak may occur in the molecular weight distribution.

As a reaction apparatus for carrying out such a method of the present invention, for example, the reaction apparatus shown in FIG. 1 can be used. The reactor 10 includes a first reactor unit 4a that houses a branch pipe 3 that branches the raw material liquid fed from the inlet 2 into the jacket 1a into eight channels, and each jacket (1b, 1c, 1d). The second to fourth reactor units (4b, 4c, 4d) having a structure in which eight fine reaction tubes (5b, 5c, 5d) having an inner diameter of 2 mm or less and sequentially increasing in the reaction solution flow direction are installed in parallel. In the jacket 1e, the flow path is bundled into one, and the fifth reactor unit 4e that accommodates the converging pipe 7 that stops polymerization by cooling and reaches the outlet 6 is connected to each reaction tube and the like 8 × 4 pieces It is a parallel microreactor consisting of unions.
Then, a radical polymerization initiator, a radical polymerizable monomer, and a polymerization medium and a chain transfer agent used as necessary are introduced from the inlet 2 and branched into eight flow paths, and the fine reaction tubes 5b, 5c, The polymerization reaction is performed through 5d, and the polymerization solution is converged and discharged from the outlet 6. On the other hand, the temperature of a temperature control fluid (hereinafter also referred to as a heat medium) flowing in each jacket is controlled to a high temperature at which the jackets 1b, 1c, and 1d can perform a polymerization reaction, and in the jackets 1a and 1e, It is controlled to a low temperature at which the polymerization reaction does not occur / or the polymerization reaction is stopped.

The present invention also provides a jacket capable of circulating a temperature control fluid and an inner diameter arranged in parallel in the jacket of 2 mm or less, and its cross-sectional area is expanded stepwise in the reaction solution flow direction. There is provided a fine chemical reaction apparatus that has a plurality of fine reaction tubes and that can control the temperature of the reaction in the plurality of fine reaction tubes by circulating a temperature control fluid through the jacket.
An example of such a fine chemical reaction apparatus is a reaction apparatus having a structure as shown in FIG. The fine chemical reaction apparatus can be easily manufactured using a circular tube having an inner diameter of 2 mm or less, which is available as a commercial product, without requiring advanced processing techniques such as photolithography, etching, and precision machining. As the material of the circular tube, for example, various metals, alloys, glass, plastics, and the like are used.
Further, as shown in FIG. 1, the jacket in the fine chemical reaction apparatus of the present invention is divided into a plurality along the length direction of the fine reaction tube, and the temperature control fluid is independently supplied to each of the divided jackets. You may have the structure which can be distribute | circulated.
Furthermore, in the fine chemical reaction apparatus of the present invention, it is preferable to have a structure in which the jacket body and the fine reaction tube part can be attached and detached. This makes it possible to replace the fine reaction tube when clogging occurs inside the fine reaction tube or when the inner diameter of the fine reaction tube is changed.
In the fine chemical reaction apparatus of the present invention, the tube shape, arrangement, number, etc. of the fine reaction tubes are not particularly limited as long as the effects of the present invention can be obtained. The shape of the jacket is the same.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Comparative Example 1
1.15 g of 2,2′-azobisisobutyronitrile was dissolved in 100 ml of toluene to prepare a radical polymerization initiator solution. Toluene used was a dehydrated grade bubbled with argon for 30 minutes or more. The butyl acrylate used was washed with 1 mol / liter sodium hydroxide aqueous solution three times and with distilled water three times, dried over sodium sulfate, filtered through sodium sulfate, and then subjected to argon bubbling for 30 minutes or more. A radical polymerization initiator solution and butyl acrylate were filled in separate syringe pumps in an argon atmosphere, and combined with a union tee at a volume ratio of 1: 1, and then a stainless steel reaction with an inner diameter of 1.76 mm. It was introduced into the tube. The reaction tube has a length of 1.3m, the first 0.8m is immersed in a thermostatic bath to bring the temperature of the thermostatic bath to 100 ° C, the remaining 0.5m is immersed in an ice bath, and a graduated cylinder is placed at the outlet of the tube. The polymerization solution was recovered.
The radical polymerization initiator solution and butyl acrylate are introduced into the reaction tube by syringe pumps in equal amounts, and the reaction solution is circulated at a flow rate of 2 minutes in the reaction part. 2.5 mL of the polymerization solution was recovered. The solvent and unreacted butyl acrylate were distilled off from the recovered solution to obtain 0.82 g of a solid containing a butyl acrylate polymer. When the mass obtained was divided by the sum of the mass of the butyl acrylate circulated (calculated with a specific gravity of 0.894 g / mL) and the mass of the polymerization initiator as a yield, it was 74%. there were.
Number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) were determined by gel permeation chromatography (GPC) measurement. Two GPC galam LF-804 made by Shodex are placed in series, calibration is performed using a commercially available methyl methacrylate polymer as a standard sample with an RI detector using tetrahydrofuran as a developing solvent at 40 ° C, and the sample is measured. ,analyzed. Moreover, the pressure gauge was installed in the exit of the syringe pump, and the pressure at the time of reaction (pressure loss of a reaction system) was measured. The results are shown in Table 1.

Comparative Example 2
In Comparative Example 1, the same procedure as in Comparative Example 1 was conducted, except that the reaction solution was passed at a flow rate such that the residence time in the reaction part was 3 minutes, and 2.6 ml of the polymerization solution was recovered in 4 minutes. 0.94 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Comparative Example 3
In Comparative Example 1, a stainless steel reaction tube having an inner diameter of 1.0 mm and a length of 3.0 m was used, the first 2.5 m was immersed in a thermostatic bath, the temperature of the thermostatic bath was set to 100 ° C., and the remaining 0.5 m was It was carried out in the same manner as in Comparative Example 1 except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 2 minutes by dipping in an ice bath and 4.9 ml of the polymerization solution was recovered in 5 minutes. 1.58 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Comparative Example 4
In Comparative Example 3, the same procedure was performed as in Comparative Example 3, except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 3 minutes, and 5.2 ml of the polymerization solution was recovered in 8 minutes. 1.87 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Comparative Example 5
In Comparative Example 1, a stainless steel reaction tube having an inner diameter of 0.5 mm and a length of 10.5 m was used, the first 10 m was immersed in a thermostatic bath, the temperature of the thermostatic bath was set to 100 ° C., and the remaining 0.5 m was ice bathed Was carried out in the same manner as Comparative Example 1 except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 2 minutes, and 4.9 ml of the polymerization solution was recovered in 5 minutes. 1.81 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Comparative Example 6
In Comparative Example 5, the same procedure was performed as in Comparative Example 5, except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 3 minutes, and 5.2 ml of the polymerization solution was recovered in 8 minutes. 2.11 g of a solid containing butyl acrylate polymer was obtained. The results are shown in Table 1.

Comparative Example 7
In Comparative Example 1, a stainless steel reaction tube having an inner diameter of 0.25 mm and a length of 10.5 m was used, the first 10 m was immersed in a thermostatic bath, the temperature of the thermostatic bath was set to 100 ° C., and the remaining 0.5 m was ice bathed Was carried out in the same manner as Comparative Example 1 except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 2 minutes, and 2.0 ml of the polymerization solution was recovered in 8 minutes. 0.70 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Comparative Example 8
In Comparative Example 7, the same procedure was performed as in Comparative Example 7, except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 3 minutes, and 2.1 ml of the polymerization solution was recovered in 13 minutes. 0.78 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Example 1
In Comparative Example 1, two stainless steel reaction tubes having an inner diameter of 0.25 mm and a length of 2 m, stainless steel reaction tubes having an inner diameter of 0.5 mm and a length of 2 m, and stainless steel reaction tubes having an inner diameter of 1.0 mm and a length of 2.5 m are provided. Connected in series by a single union, 6m from the inner diameter of 0.25mm side is immersed in the thermostatic bath to set the temperature of the thermostatic bath to 100 ° C, and the remaining 0.5m of the inner diameter 1.0mm reaction tube is placed in an ice bath. It was carried out in the same manner as in Comparative Example 1 except that the reaction solution was circulated at a flow rate at which the residence time in the reaction part was 2 minutes, and 2.1 ml of the polymerization solution was recovered in 2 minutes. 0.69 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Example 2
In Example 1, it carried out similarly to Example 1 except having distribute | circulated the reaction liquid at the flow rate used as the residence time in a reaction part for 3 minutes, and collect | recovered 2.1 milliliters of polymerization solutions in 3 minutes. 0.81 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

Example 3
Radical polymerization was carried out using a reactor unit in which eight flow paths were arranged in parallel as shown in FIG. In the reactor unit, five jackets capable of circulating a temperature control fluid are connected by 8 × 4 unions connecting reaction tubes and the like. In the first jacket, one flow path is branched into eight, and radical polymerization is performed in the reaction tube from the second jacket to the fourth jacket. The reaction tube of the second jacket has an inner diameter of 0.25 mm and a length of 2 m, the reaction tube of the third jacket has an inner diameter of 0.5 mm and a length of 2 m, and the reaction tube of the fourth jacket has an inner diameter of 1.0 mm and a length of 2 m. The configuration of the reaction tube in Examples 1 and 2 is the same. In the last jacket, the flow paths are bundled into one and the polymerization is stopped by cooling.
A toluene solution of a polymerization initiator prepared in the same manner as in Comparative Example 1 and butyl acrylate were combined with a union tee at a volume ratio of 1: 1, and then introduced into the above-described flow path paralleled reactor unit to perform polymerization. did. The first jacket was supplied with a temperature control fluid of 25 ° C, the second to fourth jackets were 100 ° C, and the fifth jacket was 0 ° C. The reaction part (second to fourth jacket) was allowed to flow at a flow rate of 2 minutes, and 4.0 mL of the reaction solution was collected from the tube connected to the outlet in 30 seconds.
The solvent and unreacted butyl acrylate were distilled off from the recovered solution to obtain 1.42 g of a solid containing a butyl acrylate polymer. The value obtained by dividing the mass of the obtained solid content by the sum of the mass of butyl acrylate circulated (calculated by a specific gravity of 0.894 g / mL) and the mass of the polymerization initiator was calculated as 78%. there were. Similar to Comparative Example 1, molecular weight and molecular weight distribution were measured. The results are shown in Table 1.

Example 4
In Example 3, the same procedure as in Example 3 was performed except that the reaction solution was circulated at a flow rate such that the residence time in the reaction part was 3 minutes, and 5.4 ml of the polymerization solution was recovered in 1 minute. 2.06 g of a solid containing a butyl acrylate polymer was obtained. The results are shown in Table 1.

As is apparent from Table 1, a polymer having a smaller molecular weight distribution can be obtained as the inner diameter of the reaction tube is reduced. However, it is considered that the pressure loss increases and the risk of clogging due to contamination by foreign substances increases. On the other hand, in Examples 1 and 2, it is apparent that a polymer having a small molecular weight distribution can be obtained while suppressing an increase in pressure loss.
Further, in Examples 3 and 4, in which eight flow paths are arranged in parallel and the volume of the reaction tube is expanded to eight times that of Examples 1 and 2, yields, molecular weights, and molecular weight distributions equivalent to those in Examples 1 and 2 are obtained. This indicates that productivity can be improved without changing the reaction results.

According to the method for producing a radical polymer of the present invention, polymerization of a radical polymerizable monomer is carried out using a fine reaction tube having an inner diameter of 2 mm or less and a cross-sectional area gradually expanding in the reaction liquid flow direction. A radical polymer having a narrow molecular weight distribution can be efficiently produced in a short time by carrying out the flow system and precisely controlling the polymerization temperature to a predetermined temperature.
Further, according to the present invention, it is possible to provide a fine chemical reaction apparatus that can be manufactured using a member that can be easily obtained without requiring an advanced processing technique.

It is a schematic sectional drawing of an example of the reaction apparatus for enforcing the method of this invention.

Explanation of symbols

1a, 1b, 1c, 1d, 1e Jacket 2 Inlet for raw material liquid 3 Branch pipe for raw material liquid 4a, 4b, 4c, 4d, 4e Reactor unit 5b, 5c, 5d Fine reaction tube 6 Outlet for polymerization liquid 7 Converging tube 10 Reactor

Claims (5)

  A radical polymerization initiator and a radical polymerizable monomer are introduced into a reaction tube having an inner diameter of 2 mm or less and a cross-sectional area gradually expanding in the direction of flow of the reaction solution. A method for producing a radical polymer, wherein a polymerization reaction is carried out in a flow form.   The method for producing a radical polymer according to claim 1, wherein the radical polymerization initiator and the radical polymerizable monomer are mixed before being introduced into the reaction tube and introduced into the reaction tube.   The method for producing a radical polymer according to claim 1 or 2, wherein the inner diameter of the reaction tube is 1 mm or less.   A jacket capable of circulating a temperature control fluid, and a plurality of reaction tubes which are arranged in parallel in the jacket and have an inner diameter of 2 mm or less and whose cross-sectional area gradually expands in the reaction liquid flowing direction A fine chemical reaction apparatus capable of controlling the temperature of the reaction in the plurality of reaction tubes by circulating a temperature control fluid through the jacket. The fine chemical reaction device according to claim 4, wherein the jacket main body and the reaction tube portion are detachable.

Images