Method for producing α-chloroethylbenzyl chloride and method for producing chloromethylstyrene

Abstract

A method for producing α-chloroethylbenzyl chloride in high yield is provided. The production method of the present invention is a method for producing α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow system, in which the gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine is flat, and the liquid phase of α-chloroethyltoluene is inclined relative to the horizontal plane, causing it to flow due to gravity. A method for producing chloromethylstyrene from methylstyrene is also provided.

Description

Technical Field

[0001] The present invention relates to a method for producing α-chloroethylbenzyl chloride. The present invention also relates to a method for producing chloromethylstyrene via α-chloroethylbenzyl chloride.

Background Art

[0002] Chloromethylstyrene is useful as a raw material for producing functional resins such as ion exchange resins, conductive resins, redox resins, and photosensitive resins, and further for applications such as water-soluble photocurable elastomers and polymer-bonded photosensitizers dispersed in water.

[0003] Conventionally, as methods for producing chloromethylstyrene, a gas-phase method and a liquid-phase method are known. The liquid-phase method for solving the drawbacks of the gas-phase method has attracted attention.

[0004] A method for producing chloromethylstyrene using the liquid-phase method has been proposed. Patent Document 1 (U.S. Patent No. 3,927,117) discloses a method for producing chloromethylstyrene by chloromethylating ethylbenzene with paraformaldehyde and hydrogen chloride, brominating the α-position of the ethyl group, and then dehydrobrominating using an amine base. Patent Document 2 (European Patent No. 345,478) discloses a method for producing chloromethylstyrene by chloromethylating phenethyl bromide with paraformaldehyde and hydrogen chloride and then dehydrobrominating with potassium hydroxide in an alcohol solvent.

[0005] Patent Documents 3 (Japanese Patent Laid-Open No. 2001-072619) and Patent Document 4 (Japanese Patent Laid-Open No. 2001-072621) disclose a method for producing α-chloroethylbenzyl chloride by chlorinating the methyl group of α-chloroethyltoluene at a conversion rate of 30 to 80% under liquid-phase conditions at a reaction temperature of 0 to 120°C.

Prior Art Documents

Patent Documents

[0006] [Patent Document 1] U.S. Patent No. 3,927,117 [Patent Document 2] European Patent No. 345,478 [Patent Document 3] Japanese Patent Publication No. 2001-072619 [Patent Document 4] Japanese Patent Publication No. 2001-072621 [Overview of the project] [Problems that the invention aims to solve]

[0007] The object of the present invention is to provide a method for producing α-chloroethyl benzyl chloride from α-chloroethyltoluene that can produce α-chloroethyl benzyl chloride in high yield. Another object of the present invention is to provide a method for producing chloromethylstyrene that can produce chloromethylstyrene in high yield. [Means for solving the problem]

[0008] The present invention relates to a method for producing α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow manner. It is preferable that the gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine is planar. It is preferable that the liquid phase of α-chloroethyltoluene is sheet-like and inclined with respect to the horizontal plane, so that the α-chloroethyltoluene flows due to gravity.

[0009] Furthermore, the present invention relates to a method for producing chloromethylstyrene from methylstyrene, (1) A step of reacting methylstyrene with hydrogen chloride to obtain α-chloroethyltoluene, (2) The above method, which involves a photoreaction of α-chloroethyltoluene with chlorine in a flow manner to obtain α-chloroethylbenzyl chloride. (3) A step to obtain chloromethylstyrene by dehydrochlorinating α-chloroethylbenzyl chloride. The present invention provides a manufacturing method comprising [the specified element].

[0010] Preferred embodiments of the present invention are as follows: [1] A method for producing α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow manner, A manufacturing method in which the gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine is planar, and the liquid phase of α-chloroethyltoluene is inclined with respect to the horizontal plane and flows due to gravity. [2] Regarding the liquid phase of α-chloroethyltoluene, the thickness is 0.1 to 5 cm, the width is 0.3 to 300 cm, and the length in the longitudinal direction (flow direction) is 5 to 300 cm. The manufacturing method described in item [1], wherein the planar gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine has a width of 0.3 to 300 cm and a length in the longitudinal direction (flow direction) of 5 to 300 cm.

[0011] [3] The manufacturing method according to item [1] or [2], wherein the migration rate of the liquid phase of α-chloroethyltoluene is 0.1 to 50 cm / second and the migration rate of the gas phase of chlorine is 0.1 to 100 cm / second. [4] The manufacturing method according to any one of the items [1] to [3], wherein the irradiation time of chlorine with light is 0.01 to 1000 seconds. [5] The method for producing α-chloroethyltoluene according to any one of the items [1] to [4], wherein the liquid phase of α-chloroethyltoluene is a monochannel or a multichannel in which the channels are separated in the width direction.

[0012] [6] Flow-type photoreactions are carried out using a flow reactor, which is either a mono-channel or multi-channel flow reactor. A multi-channel flow reactor, A reaction case for reacting while flowing a liquid, and a support base that supports the reaction case while inclining it so that the liquid flows by its own weight, comprising: The reaction case is a flow path portion having a flow path groove for flowing the liquid, comprising a gas flow portion for flowing gas so as to contact the flow path groove, At the upstream end of the reaction case, a liquid supply portion for supplying liquid to the flow path groove and a gas supply portion for supplying gas to the gas phase flow portion are provided, At the downstream end of the reaction case, a liquid discharge portion for discharging the liquid that has flowed through the flow path groove and a gas discharge portion for discharging the gas that has flowed through the gas phase flow portion are provided, The liquid supply portion is configured to supply while storing the liquid and overflowing it with respect to the upstream end of the flow path groove. The production method according to any one of items [1] to [5].

[0013] [7] A method for producing chloromethylstyrene from methylstyrene, comprising: (1) A step of reacting methylstyrene with hydrogen chloride to obtain α-chloroethyltoluene, [[ID=XX]](2) A step of subjecting α-chloroethyltoluene to a photoreaction with chlorine in a flow type to obtain α-chloroethylbenzyl chloride, which is the method according to any one of items [1] to [6]. (3) A step of dehydrochlorinating α-chloroethylbenzyl chloride to obtain chloromethylstyrene The production method comprising the above steps. [[ID=XX]]

[0014] [[ID=XX]] [8] The production method according to item [7], wherein the solvent in the dehydrochlorination step (3) contains N,N-dimethylformamide (DMF). [9] A reaction product containing α-chloroethylbenzyl chloride obtained by subjecting α-chloroethyltoluene to a photoreaction with chlorine in a flow type, where the conversion rate of α-chloroethyltoluene is 82% or more, and is a reaction product for producing chloromethylstyrene.

[10] The reaction product according to item [9], wherein the yield of α-chloroethylbenzyl chloride is 45% or more.

[11] For the production of chloromethylstyrene, use of a reaction product obtained by photoreacting α-chloroethyltoluene with chlorine in a flow manner, wherein the conversion rate of α-chloroethyltoluene is 82% or more and the yield of α-chloroethylbenzyl chloride is 45% or more. [Effects of the Invention]

[0015] The present invention provides a method for producing α-chloroethylbenzyl chloride, which allows for the efficient chlorination of α-chloroethyltoluene even at room temperature. It enables a high conversion rate of α-chloroethyltoluene. Even with a high conversion rate, α-chloroethylbenzyl chloride can be obtained with high selectivity. The chlorination reaction can be performed with a short reaction time, high yield, and low by-product yield. In particular, it allows for a higher conversion rate and lower by-product yield compared to batch reactors. The chlorination reaction can be easily controlled. Furthermore, there is no need to isolate α-chloroethyltoluene from the product mixture obtained from the α-chloroethyltoluene manufacturing process; the product mixture can be directly subjected to the α-chloroethylbenzyl chloride manufacturing process. α-chloroethylbenzyl chloride can be manufactured with high conversion rates and high selectivity without isolating α-chloroethyltoluene. According to the method for producing chloromethylstyrene in the present invention, chloromethylstyrene can be produced in high yield using a simple apparatus. [Brief explanation of the drawing]

[0016] [Figure 1] This is a side view of a multi-channel flow reactor that can be used in the present invention. [Figure 2] This is a schematic diagram showing how a liquid flows through a flow reactor. [Figure 3]This is a plan view of the reaction case in a flow reactor. [Figure 4] This is a cross-sectional view of XX in Figure 3. [Figure 5] This is a cross-sectional view from XI-XI in Figure 4. [Figure 6] This is a cross-sectional view from line XII-XII in Figure 4. [Figure 7] This is a perspective view schematic of the upstream portion of the reaction case. [Modes for carrying out the invention]

[0017] A method for producing chloromethylstyrene from methylstyrene is: (1) A step of reacting methylstyrene with hydrogen chloride to obtain α-chloroethyltoluene, (2) A step of obtaining α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow manner, (3) A step to obtain chloromethylstyrene by dehydrochlorinating α-chloroethylbenzyl chloride. It holds.

[0018] [Process (1)] TIFF0007883250000001.tif2066

[0019] Step (1) is a step in which methylstyrene (liquid) is reacted with hydrogen chloride gas to obtain α-chloroethyltoluene. Step (1) is a hydrogen chloride addition reaction step in which hydrogen chloride is added to methylstyrene. Methylstyrene has isomers called o-methylstyrene, m-methylstyrene, and p-methylstyrene, depending on the substitution position of the methyl group relative to the vinyl group. Generally, depending on the chloromethylstyrene being produced, o-methylstyrene, m-methylstyrene, p-methylstyrene, or mixtures thereof are used as methylstyrene. Since p-chloromethylstyrene is important for applications such as non-isocyanate lens material monomers, cationic ion exchange resins, and components of modified polymers (photocurable elastomers, photosensitizers), p-methylstyrene is preferred.

[0020] To protect the vinyl group when introducing chlorine to the methyl group of methylstyrene, α-chloroethyltoluene is produced by adding hydrogen chloride to the vinyl group of methylstyrene. This hydrogen chloride addition reaction may be carried out by contacting methylstyrene with hydrogen chloride gas or by using hydrochloric acid. From the viewpoint of conversion rate and post-treatment, the reaction carried out by contacting methylstyrene with hydrogen chloride gas is preferred.

[0021] The hydrogen chloride addition reaction is preferably carried out in the presence of an iron masking agent, such as triphenylphosphine oxide [(C6H5)3P=O] or tributylphosphine oxide [[CH3(CH2)3]3P=O]. The use of an iron masking agent effectively suppresses the formation of a Friedel-Crafts type condensate of the resulting α-chloroethyltoluene, thereby improving the yield of α-chloroethyltoluene.

[0022] The reaction temperature for the hydrogen chloride addition reaction is usually 0 to 100°C, for example, 30 to 70°C. The reaction time may be 0.5 to 24 hours, for example, 6 to 9 hours. Since the starting material, methylstyrene, is a liquid at room temperature (20°C), the reaction may be carried out without a solvent. Alternatively, to improve the utilization rate of hydrogen chloride, methylstyrene may be dissolved in an organic solvent such as carbon tetrachloride, methylene chloride, or chloroform. Hydrogen chloride gas may be used as is, or it may be diluted with an inert gas such as nitrogen gas to suppress by-product formation.

[0023] [Process (2)] TIFF0007883250000002.tif2483

[0024] Step (2) is a process to produce α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene (liquid) with chlorine gas in a flow manner. Chlorine is introduced to the methyl group of α-chloroethyltoluene to produce α-chloroethylbenzyl chloride. α-Chloroethyltoluene is generally the reaction product obtained in step (1). Before proceeding with step (2), the reaction product from step (1) may be purified by distillation or other means, or it may not be purified. Even without purifying the reaction product, a high conversion rate, high selectivity, and high yield are obtained. This process involves a reaction between a liquid phase and a gas phase, and can therefore be classified as a gas-liquid reaction.

[0025] The reaction to introduce chlorine to the methyl group of α-chloroethyltoluene, that is, the reaction to chlorinate the benzyl position, is carried out in a flow manner under light irradiation. The liquid phase of α-chloroethyltoluene is generally sheet-like. "Sheet-like" means a shape in which the area (main surface formed by width and length) or length (or width and length) is sufficiently large compared to the thickness. "Sheet-like" also includes rod-like forms in which the width of the α-chloroethyltoluene liquid phase is reduced.

[0026] The liquid phase of α-chloroethyltoluene preferably has a thickness of 0.1 to 5 cm, for example 0.5 to 2 cm, a width of 0.3 to 300 cm, for example 3 to 30 cm, and a length in the longitudinal direction (flow direction) of 5 to 300 cm, for example 10 to 100 cm. The gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine is preferably planar. The gas-liquid interface is preferably 0.3 to 300 cm wide, for example 3 to 30 cm, and has a length of 5 to 300 cm in the longitudinal direction (flow direction), for example 10 to 100 cm.

[0027] Preferably, the liquid phase migration speed of α-chloroethyltoluene is 0.1 to 50 cm / sec or 0.1 to 30 cm / sec, for example 0.5 to 25 cm / sec, particularly 1 to 10 cm / sec, and the gas phase migration speed of chlorine is 0.1 to 100 cm / sec, 0.5 to 100 cm / sec, or 0.1 to 60 cm / sec, for example 1 to 50 cm / sec or 1 to 20 cm / sec, particularly 2 to 40 cm / sec. The liquid phase migration speeds of α-chloroethyltoluene and chlorine may be the same or different. The liquid phase migration speed of α-chloroethyltoluene may be slower or faster than the gas phase migration speed of chlorine.

[0028] Preferably, the α-chloroethyltoluene liquid phase is separated in the width direction, and the α-chloroethyltoluene liquid phase is multi-channel. In the multi-channel configuration, it is preferable that the width of each channel is the same and the flow rate in each channel is approximately the same. The number of channels is, for example, 2 to 50, preferably 2 to 40, more preferably 2 to 20, and particularly preferably 3 to 15. The width of the channels is, for example, 1 mm to 70 mm, preferably 2 mm to 50 mm, and more preferably 3 mm to 30 mm.

[0029] In a flow-type chlorination reaction, the reaction temperature is preferably -30 to 100°C, for example 0 to 60°C, particularly 10 to 40°C, and especially room temperature (20°C), and the reaction time is preferably 0.1 to 1000 seconds, for example 0.5 to 100 seconds, and particularly 1 to 60 seconds.

[0030] Flow-type photoreactions may be carried out using a flow reactor, which may be a mono-channel or multi-channel flow reactor. The flow reactor It comprises a reaction case in which a liquid is allowed to flow and a support stand that tilts and supports the reaction case so that the liquid flows by its own gravity. The reaction case is, A flow channel section having a flow channel groove for flowing liquid, It is equipped with a gas flow section that allows gas to flow in contact with the flow channel groove, The reaction case is equipped with a liquid supply unit that supplies liquid to the flow channel groove and a gas supply unit that supplies gas to the gas phase flow section at its upstream end. At the downstream end of the reaction case, there is a liquid discharge section for discharging the liquid that has flowed through the flow channel groove, It is equipped with a gas discharge section that discharges the gas that has flowed through the gas phase circulation section, The liquid supply unit is preferably configured to store the liquid and supply it while allowing it to overflow to the upstream end of the flow channel groove.

[0031] A multi-channel flow reactor, A reaction case in which a reaction occurs while a liquid is flowing, A support stand that tilts and supports the reaction case so that the liquid flows by its own gravity, It is equipped with, The reaction case is, A flow channel section having multiple parallel flow channel grooves for flowing liquid, A gas flow section that allows gas to flow in contact with the flow channel groove, A liquid supply unit is connected to the upstream end of the flow channel and supplies liquid to the flow channel groove. A liquid discharge section is connected to the downstream end of the flow channel and discharges the liquid that has flowed through the flow channel groove. It is equipped with, The liquid supply unit is preferably configured to supply the liquid in equal amounts to each channel groove.

[0032] The wavelength of the irradiated light can be 100-800 nm, for example, 200-600 nm. The light intensity is not limited, but should be between 1 and 10,000 mW / cm². 2 For example, 5-1000 mW / cm² 2 It may be the case that the irradiation time of light to α-chloroethyltoluene and chlorine is preferably 0.01 to 1000 seconds or 0.01 to 30 seconds, for example 0.5 to 750 seconds or 0.05 to 10 seconds, particularly 1 to 500 seconds.

[0033] The chlorination reaction may be carried out in the presence of a radical initiator. Specific examples of radical initiators include azobisisobutyronitrile and benzoyl peroxide. In chlorination reactions, when using chlorine gas, dilution of the chlorine gas is optional. Dilution can be performed using noble gases and inert gases such as nitrogen gas.

[0034] The conversion rate of α-chloroethyltoluene (raw material) in the chlorination reaction is 50% or more, preferably 75% or more, for example 80% or more, particularly 82% or more, and especially 85-99.9%. According to the present invention, α-chloroethylbenzyl chloride can be produced in high yield even with a high conversion rate. The yield of α-chloroethylbenzyl chloride (product) in the chlorination reaction is preferably 30% or more, more preferably 40% or more, for example 45% or more, and particularly preferably 50% or more. The upper limit of the yield may be 90%, 70%, or 65%.

[0035] Step (2) is preferably carried out using a multi-channel flow reactor as disclosed in Patent Application No. 2018-110336 (WO2019 / 235582A1) (the disclosure of this application is incorporated into this specification by reference).

[0036] A multi-channel flow reactor is, A reaction case in which a reaction occurs while a liquid is flowing, A support stand is provided to tilt and support the reaction case so that the liquid flows under its own weight, It is equipped with, The aforementioned reaction case is A flow channel section having multiple parallel flow channel grooves for flowing liquid, A gas flow section for circulating gas so as to be in contact with the aforementioned flow channel groove, A liquid supply unit is connected to the upstream end of the aforementioned flow channel and supplies liquid to the aforementioned flow channel groove, A liquid discharge section is connected to the downstream end of the aforementioned flow channel and discharges the liquid that has flowed through the flow channel groove, It is equipped with, The liquid supply unit is configured to store the liquid and supply it while simultaneously overflowing it to the upstream ends of the plurality of flow channels. It is characterized by the following.

[0037] Figures 1-5 show a multi-channel flow reactor.

[0038] Figure 1 is a side view (partially transparent side view) of a flow reactor. In Figure 1, the right side is the "upstream" and the left side is the "downstream". The flow reactor 100 comprises a reaction case 10, a support base 20 that supports the reaction case 10, and a light source 30.

[0039] Figure 2 is a schematic diagram showing how the liquid flows through the flow reactor. The stored liquid overflows from the storage chamber 15 and flows downstream due to gravity.

[0040] Figure 3 is a plan view of the reaction case. Figure 4 is a cross-sectional view of XX in Figure 3. Figure 5 is a cross-sectional view taken along line XI-XI in Figure 4. Figure 6 is a cross-sectional view taken along line XII-XII in Figure 4. Figure 7 is a schematic perspective view of the upstream portion of the reaction case.

[0041] The reaction case 10 consists of a substrate 1, a lid 2 that covers the substrate 1, and a holding frame 3 that surrounds and grips the substrate 1 and the lid 2. In the reaction case 10, liquid is introduced into each storage chamber 15 from the liquid inlet 151, overflows, and flows into each flow channel groove 13. Gas is introduced from the gas inlet 141 and flows through the space 5. The liquid overflows from the liquid supply section and flows into the flow channel section by gravity. The longitudinal dimension of the substrate 1 may be, for example, 5 cm to 300 cm, preferably 7 to 200 cm, and more preferably 10 to 100 cm. The width dimension of the substrate 1 may be, for example, 0.3 cm to 300 cm, preferably 1 to 200 cm, and more preferably 3 to 30 cm.

[0042] In Figures 1-7, 5 is space, 10A is the flow path section, 10B is the gas flow section, 10C is the liquid supply section, 10D is the liquid discharge section 10D, 13 is the flow path groove, 15 and 16 are the storage chambers, 21 is the upstream vertical frame, 22 is the downstream vertical frame, 23 is the horizontal frame, 25 is the through hole, 26 is the hinge mechanism, 31 is the light source support base, 122 and 155 are partition walls, 141 is the gas inlet, 142 is the gas outlet, 151 is the liquid inlet, 152 is the liquid outlet, 241 and 244 are wing bolts, 242 is a screw, and 243 is a fastener.

[0043] The apparatus shown in Figure 1 allows for the production of α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow manner.

[0044] [Process (3)] TIFF0007883250000003.tif1975

[0045] Step (3) is a step in which α-chloroethylbenzyl chloride is dehydrochlorinated to obtain chloromethylstyrene. Generally, the reaction product produced in step (2) is dehydrochlorinated. Before performing step (3), the reaction product from step (2) may be purified by distillation or other means, or it may not be necessary to purify it. Step (3) can be performed without the need to purify the reaction product from step (2).

[0046] The dehydrochlorination reaction may be carried out in a solvent, using a base, and optionally in the presence of a phase transfer catalyst. Examples of solvents include alcohols such as methanol, ethanol, propanol, butanol, s-butanol, t-butanol (t-BuOH), pentanol, hexanol, and phenol; hydrocarbons such as hexane, heptane, octane, nonane, benzene, toluene, xylene, and mesitylene; ketones such as acetone, 2-butanone, 2-pentanone, and 3-pentanone; ethers such as diethyl ether, diisopropyl ether, cyclopentyl methyl ether, methyl-t-butyl ether, diphenyl ether, tetrahydrofuran (THF), 1,4-dioxane, and tetrahydropyran; nitriles such as acetonitrile, propionitrile, and benzonitrile; and N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide. N,N-dimethylformamide (DMF) is particularly preferred.

[0047] Examples of bases include alkali metals (e.g., potassium, sodium, cesium) and alkaline earth metals (e.g., magnesium, calcium, strontium, barium) and alkoxides (alkoxides with e.g., 1 to 10 carbon atoms), salts, carbonates, or bicarbonates, such as potassium t-butoxide (t-BuOK), potassium ethoxide, potassium methoxide, sodium t-butoxide, sodium ethoxide, sodium methoxide, sodium carbonate, sodium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, magnesium carbonate, sodium bicarbonate, and potassium bicarbonate. Examples of phase-transfer catalysts include tetrabutylammonium bromide (TBAB) and tetrabutylammonium chloride.

[0048] Alternatively, the dehydrochlorination reaction may be carried out by heated dehydrochlorination distillation under chloromethylstyrene distillation conditions at a temperature of 100-200°C.

[0049] The reaction temperature for the dehydrochlorination reaction is preferably in the range of 120 to 180°C, particularly 150 to 170°C, and the reaction time is preferably 0.5 to 24 hours. A polymerization inhibitor may be added to suppress the polymerization of the resulting chloromethylstyrene and thereby increase the yield. Heat-induced dehydrochlorination distillation is advantageous in terms of manufacturing costs and the purification of chloromethylstyrene.

[0050] By carrying out the dehydrochlorination reaction of α-chloroethylbenzyl chloride using this heated dehydrochlorination distillation, chloromethylstyrene is separated by distillation simultaneously with the dehydrochlorination reaction, and a primary fraction mainly composed of methylstyrene and α-chloroethyltoluene and a secondary fraction mainly composed of chloromethylstyrene and α-chloroethylbenzyl chloride are usually obtained.

[0051] The main fraction obtained by the dehydrochlorination reaction, which consists mainly of chloromethylstyrene and α-chloroethylbenzyl chloride, is purified by vacuum distillation in the presence of a polymerization inhibitor to obtain chloromethylstyrene with a purity of usually 95% by weight or more, preferably 99% by weight or more, as the rectified fraction.

[0052] Examples of polymerization inhibitors include t-butylcatechol, 2,4-dinitrophenol, hydroquinone, N-nitrosophenylhydroxyamine, ammonium salt, N-nitrosophenylhydroxyamine aluminum salt, nitromethane, phenothiazine, or mixtures of two or more of these. The amount of polymerization inhibitor used is usually in the range of 500 to 2000 ppm, preferably 500 to 1000 ppm. Furthermore, vacuum distillation in this process may be carried out under reduced pressure of usually 1 to 300 mmHg, preferably 3 to 200 mmHg, with a reflux ratio of 0.2 to 7, preferably 0.2 to 5, and a distillation temperature of 50 to 120°C, preferably 60 to 100°C.

[0053] Preferred embodiments of the present invention will be specifically described below based on the examples provided. In the examples, parts, percentages, or ratios refer to parts by weight, weight percentages, or weight ratios unless otherwise specified. In the examples, step (2) (a step to produce α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow manner) was performed using a multi-channel flow reactor as shown in Figures 1 to 5.

[0054] Example 1 (1) Hydrogen chloride addition reaction (Step 1): Methylstyrene (liquid) and hydrogen chloride (liquid) were placed in a reaction vessel, and a hydrogen chloride addition reaction was carried out. In a reaction vessel equipped with a condenser and an exhaust gas trap, 101 g (0.86 mol) of liquid methylstyrene and 221 g (2.1 mol, 2.5 equivalents of methylstyrene) of 35% liquid hydrogen chloride were charged. The reaction was carried out by stirring for 6 hours while maintaining the reaction temperature at 65°C to perform the hydrogen chloride addition reaction of methylstyrene. After the reaction was complete, the organic layer was separated from the reaction mixture, neutralized and washed with saturated sodium bicarbonate aqueous solution, then dehydrated with anhydrous magnesium sulfate, and filtered. Gas chromatography (GC) analysis revealed that the proportion of α-chloroethyltoluene in the obtained crude product (mixture) was 86%. This value was calculated using the GC area percentage.

[0055] (2) Photochlorination reaction (step 2): A mixture containing α-chloroethyltoluene obtained by the above hydrogen chloride addition reaction step and chlorine gas were introduced into reaction case 10, and the photochlorination reaction of α-chloroethyltoluene (step 2) by light irradiation from a light source was carried out in a flow system in a multi-channel flow reactor 100.

[0056] Prior to the reaction, the temperature of the reactor's upstream, midstream, and downstream was adjusted to 23°C by circulating water at 23°C through reaction case 10. Next, the α-chloroethyltoluene mixture was introduced into reaction case 10 at a flow rate of 20 mL / min (113.3 mmol / min) and chlorine gas was continuously introduced into reaction case 10 at a flow rate of 4.1 L / min (183.0 mmol / min). The charge ratio (equivalent ratio) of chlorine / chloroethyltoluene was 1.6, and the chlorine gas transfer rate was 17.1 cm / second. Reaction case 10 was irradiated with light from light source 30 (wavelength: 365 nm) at a light intensity of 120 W, and the photochlorination reaction in the flow system was carried out in reaction case 10. Analysis by GC (gas chromatography) showed that the conversion rate of α-chloroethyltoluene was 52.9%, the selectivity of α-chloroethylbenzyl chloride was 63.0%, and the yield of α-chloroethylbenzyl chloride was 33.4%. These values ​​were calculated using GC area percentage.

[0057] (3) Dehydrochlorination reaction (step 3): The dehydrochlorination reaction of α-chloroethylbenzyl chloride obtained by the above photochlorination reaction was carried out in a benzonitrile solution in the presence of a polymerization inhibitor and with potassium carbonate as the base. 81.7 g of α-chloroethylbenzyl chloride (68% by weight) was placed in a reaction vessel equipped with a condenser, and 120 g of potassium carbonate, 757 mg of t-butylcatechol, and 216 mL of benzonitrile were added. These conditions correspond to 294 mmol of α-chloroethylbenzyl chloride, 868 mmol of potassium carbonate (3.0 equivalents of α-chloroethylbenzyl chloride), and 4.6 mmol of t-butylcatechol (1.6 mol% of α-chloroethylbenzyl chloride). The dehydrochlorination reaction was carried out for 10 hours while stirring the solution and maintaining the temperature at 165°C. After the reaction was complete, analysis by GC (gas chromatography) revealed that the conversion rate of α-chloroethylbenzyl chloride was 53.1%, and the yield of chloromethylstyrene was 41.1%.

[0058] Example 2 Photochlorination reaction (step 2): The procedure was repeated in the same manner as the photochlorination reaction (step 2) in Example 1, except that the flow rate of the α-chloroethyltoluene mixture was changed to 5 mL / min (28.2 mmol / min) and the flow rate of chlorine gas was changed to 2.1 L / min (93.8 mmol / min). The charging ratio (equivalent ratio) of chlorine / chloroethyltoluene was 3.3, and the chlorine gas transfer rate was 8.8 cm / second. Analysis by area percentage using gas chromatography (GC) revealed that the conversion rate of α-chloroethyltoluene was 89.8%, the selectivity of α-chloroethylbenzyl chloride was 54.8%, and the yield of α-chloroethylbenzyl chloride was 49.2%.

[0059] Example 3 Photochlorination reaction (step 2): Using α-chloroethyltoluene purified by distillation, the same procedure as in Example 1 (step 2) was repeated, except that the flow rate of α-chloroethyltoluene was changed to 5 mL / min (32.3 mmol / min) and the flow rate of chlorine gas was changed to 2.1 L / min (93.8 mmol / min). Analysis by area percentage using gas chromatography (GC) revealed that the conversion rate of α-chloroethyltoluene was 90.0%, the selectivity of α-chloroethylbenzyl chloride was 48.3%, and the yield of α-chloroethylbenzyl chloride was 43.5%.

[0060] Example 4 Dehydrochlorination reaction (step 3): A reaction vessel equipped with a thermometer, magnetic stirrer, and reflux condenser was charged with a mixture (152.3 g) containing α-chloroethylbenzyl chloride (55.9 g) and chloroethylbenzene (96.4 g), N,N-dimethylformaldehyde (200 ml), 2,6-dinitro-p-cresol (1.6 g), and tetrabutylammonium chloride (11.2 g). The mixture in the reaction vessel was heated and reacted at 150°C for 3.5 hours. A portion of the reaction solution was withdrawn and analyzed by gas chromatography. The conversion rate of α-chloroethylbenzyl chloride was 98.2%, the yield of chloromethylstyrene was 89.3% relative to α-chloroethylbenzyl chloride, and the molar ratio of m-chloromethylstyrene to p-chloromethylstyrene was 51:49. [Industrial applicability]

[0061] Chloromethylstyrene is useful as a raw material for the manufacture of functional resins such as ion exchange resins, conductive resins, oxidation-reduction resins, and photosensitive resins, and as a modifier for various resins and rubbers. In addition, chloromethylstyrene is also useful as a raw material for various industrial applications, such as water-soluble photocurable elastomers, water-dispersible polymer-bonded photosensitizers, and silane coupling agents.

[0062] Other aspects of the present invention are as follows: [1] A method for producing α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine in a flow manner, A manufacturing method in which the gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine is planar, the liquid phase of α-chloroethyltoluene is in the form of a sheet, and the liquid phase of α-chloroethyltoluene is inclined with respect to the horizontal plane and flows due to gravity. [2] Regarding the liquid phase of α-chloroethyltoluene, the thickness is 0.1 to 5 cm, the width is 0.3 to 300 cm, and the length in the longitudinal direction (flow direction) is 5 to 300 cm. The manufacturing method according to item [1], wherein the gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine is planar, has a width of 0.3 to 300 cm, and a length in the longitudinal direction (flow direction) of 5 to 300 cm.

[0063] [3] The manufacturing method according to item [1] or [2], wherein the migration rate of the liquid phase of α-chloroethyltoluene is 0.1 to 10 cm / second and the migration rate of the gas phase of chlorine is 0.1 to 20 cm / second. [4] The method for producing α-chloroethyltoluene and chlorine in any of the following items [1] to [3], wherein the irradiation time of light to α-chloroethyltoluene and chlorine is 0.01 to 30 seconds. [5] A method for producing α-chloroethyltoluene according to any one of the items [1] to [4], wherein the liquid phase of α-chloroethyltoluene is separated in the width direction and the liquid phase of α-chloroethyltoluene is multichannel.

[0064] [6] Flow-type photoreactions are performed using a multi-channel flow reactor. A multi-channel flow reactor, A reaction case in which a reaction occurs while a liquid is flowing, A support stand that tilts and supports the reaction case so that the liquid flows by its own gravity, It is equipped with, The reaction case is, A flow channel section having multiple parallel flow channel grooves for flowing liquid, A gas flow section that allows gas to flow in contact with the flow channel groove, A liquid supply unit is connected to the upstream end of the flow channel and supplies liquid to the flow channel groove. A liquid discharge section is connected to the downstream end of the flow channel and discharges the liquid that has flowed through the flow channel groove. It is equipped with, The manufacturing method according to any one of items [1] to [5], wherein the liquid supply unit is configured to supply liquid in equal amounts to each flow channel groove.

[0065] [7] A method for producing chloromethylstyrene from methylstyrene, (1) A step of reacting methylstyrene with hydrogen chloride to obtain α-chloroethyltoluene, (2) A step which is a method according to any of the items [1] to [6], in which α-chloroethyltoluene is photoreacted with chlorine in a flow formula to obtain α-chloroethylbenzyl chloride, (3) A step to obtain chloromethylstyrene by dehydrochlorinating α-chloroethylbenzyl chloride. A manufacturing method comprising [the specified element].

[0066] [8] A reaction product containing α-chloroethylbenzyl chloride, obtained by photoreacting α-chloroethyltoluene with chlorine in a flow manner, A reaction product for the production of chloromethylstyrene, having a conversion rate of α-chloroethyltoluene of 82% or more. [9] The reaction product according to item [8], wherein the yield of α-chloroethylbenzyl chloride is 45% or more.

[10] For the production of chloromethylstyrene, use of a reaction product obtained by photoreacting α-chloroethyltoluene with chlorine in a flow manner, wherein the conversion rate of α-chloroethyltoluene is 82% or more and the yield of α-chloroethylbenzyl chloride is 45% or more. [Explanation of Symbols]

[0067] 1 circuit board 2 Lid 3. Holding slots 10 reaction cases 10A Flow channel section 10B Gas flow section 10C Liquid supply section 10D Liquid drain 13 Flow channel groove 15, 16 Storage chamber 30 light source 100 Flow Reactor

Claims

1. A method for producing α-chloroethylbenzyl chloride by photoreacting α-chloroethyltoluene with chlorine gas in a flow manner under light irradiation, The liquid phase of α-chloroethyltoluene is a multi-channel system in which the channels are separated in the width direction. The gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine gas is planar and inclined. The liquid phase of α-chloroethyltoluene stored in the storage chamber branches off from the storage chamber and overflows in each channel, flowing downstream by gravity. The chlorine gas flows downstream along the sheet-like liquid phase, and A manufacturing method in which the liquid phase of α-chloroethyltoluene containing α-chloroethylbenzyl chloride, which is produced by a photoreaction, is inclined with respect to a horizontal plane and flows due to gravity.

2. Regarding the liquid phase of α-chloroethyltoluene, the thickness is 0.1 to 5 cm, the width is 0.3 to 300 cm, and the length in the longitudinal direction (flow direction) is 5 to 300 cm. The manufacturing method according to claim 1, wherein the planar gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine gas has a width of 0.3 to 300 cm and a length in the longitudinal direction (flow direction) of 5 to 300 cm.

3. The manufacturing method according to claim 1 or 2, wherein the migration speed of the liquid phase of α-chloroethyltoluene is 0.1 to 50 cm / second, and the migration speed of the gas phase of chlorine gas is 0.1 to 100 cm / second.

4. The manufacturing method according to any one of claims 1 to 3, wherein the irradiation time of light to chlorine gas is 0.01 to 1000 seconds.

5. Flow-type photoreactions are carried out using a multi-channel flow reactor. The flow reactor It comprises a reaction case in which a liquid is allowed to flow and a support stand that tilts and supports the reaction case so that the liquid flows by its own gravity. The reaction case is, A flow channel section having a flow channel groove for flowing liquid, It is equipped with a gas flow section that allows gas to flow in contact with the flow channel groove, The upstream end of the reaction case is equipped with a liquid supply unit that supplies liquid to the flow channel groove and a gas supply unit that supplies gas to the gas phase flow section. At the downstream end of the reaction case, there is a liquid discharge section for discharging the liquid that has flowed through the flow channel groove, It is equipped with a gas discharge section that discharges the gas that has flowed through the gas phase circulation section, The manufacturing method according to any one of claims 1 to 4, wherein the liquid supply unit is configured to store liquid and supply it while overflowing it to the upstream end of the flow channel groove.

6. A method for producing chloromethylstyrene from methylstyrene, (1) A step of reacting methylstyrene with hydrogen chloride to obtain α-chloroethyltoluene, (2) A step according to any one of claims 1 to 5, wherein α-chloroethyltoluene is photoreacted with chlorine gas in a flow manner to obtain α-chloroethylbenzyl chloride. (3) A step to obtain chloromethylstyrene by dehydrochlorinating α-chloroethylbenzyl chloride. A manufacturing method comprising [the specified element].

7. The manufacturing method according to claim 6, wherein the solvent in the dehydrochlorination step (3) is N,N-dimethylformamide (DMF).

8. A method for producing α-chloroethylbenzyl chloride, comprising the step of photoreacting α-chloroethyltoluene with chlorine gas in a flow manner under light irradiation to obtain a reaction product, The liquid phase of α-chloroethyltoluene is a multi-channel system in which the channels are separated in the width direction. The gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine gas is in contact with a planar, inclined surface. The liquid phase of α-chloroethyltoluene stored in the storage chamber branches off from the storage chamber and overflows in each channel, flowing downstream by gravity. The chlorine gas flows downstream along the sheet-like liquid phase. The liquid phase of α-chloroethyltoluene containing α-chloroethylbenzyl chloride, which is produced by a photoreaction, is inclined with respect to a horizontal plane and flows due to gravity. A method for producing α-chloroethyltoluene in which the reaction product obtained directly from the reaction has a conversion rate of 82% or more.

9. The production method according to claim 8, wherein the yield of α-chloroethylbenzyl chloride is 45% or more.

10. The liquid phase of α-chloroethyltoluene is a multi-channel system in which the channels are separated in the width direction, the gas-liquid interface between the liquid phase of α-chloroethyltoluene and the gas phase of chlorine gas is in a planar, inclined contact, the liquid phase of α-chloroethyltoluene stored in the storage chamber branches and overflows from the storage chamber in each channel and flows downstream by gravity, the chlorine gas flows downstream along the sheet-like liquid phase, The liquid phase of α-chloroethyltoluene containing α-chloroethylbenzyl chloride, which is produced by a photoreaction, is inclined to a horizontal plane and flows by gravity. The α-chloroethyltoluene is photoreacted with chlorine gas in a flow manner under light irradiation, and the conversion rate of α-chloroethyltoluene is 82% or more, and the yield of α-chloroethylbenzyl chloride is 45% or more. The reaction product obtained from this reaction is used directly for the production of chloromethylstyrene.

Images