JPH1112201A - Production of methallyl chloride - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for stably producing methallyl chloride in high yield by homogeneously mixing chlorine gas with isobutylene gas, and homogeneously dispersing the mixed both gases into a solvent. SOLUTION: In a method for producing methallyl chloride by mixing chlorine gas with isobutylene gas and supplying into a solvent, supplying molar ratio of both gases (isobutylene/chlorine) is made to (0.9/1.1)-(1.1/0.9), and a static mixer is provided in a flowing path of the mixed both gases. The mixed gases are supplied through a dispersing device having many capillaries adjusted that each equivalent flow rate of the gases are ejected from the respective capillaries and any abnormally staying space of the gases is not generated in the inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing methallyl chloride. Methallyl chloride is a compound having a unique structure having both a highly reactive double bond and chlorine, and is used as a raw material or an intermediate of various chemical products. In particular, there is a great demand for a raw material of sodium methallyl sulfonate, which is a dyeing aid for acrylic fibers, and this compound has become a major use. It is also a useful substance as a raw material for various pesticides.

[0002]

2. Description of the Related Art Various methods for producing methallyl chloride have been reported, but a method for producing methallyl chloride from chlorine gas and isobutylene gas is generally used. For example, Japanese Patent Publication No. 53-3940
No. 2 discloses a method of supplying a mixture of both gases into a product liquid. In this publication, it is stated that, with respect to the mixing of both gases, it is sufficient just to join the supply pipes of both gases immediately before the inlet of the reactor to achieve the purpose, and no further specific technology is disclosed.

However, as a result of a detailed examination by the present inventors, the yield of methallyl chloride and the mixed state of both gases are closely related in the present reaction. It is indispensable to mix them very uniformly, and it has been found that the creation of technology for that is essential. As will be described later, if the reaction is carried out in an insufficiently mixed state, the ratio of side reactions such as the reaction between by-produced hydrogen chloride and isobutylene and the reaction between generated methallyl chloride and chlorine increases, and as a result, The yield of methallyl chloride decreases.

[0004] A simple method generally used for mixing two kinds of gases, for example, a simple double tube method, In
dustrial and engineering
Chemistry VOL. 31, NO. 11, p.
The branch pipe system shown in FIG. 1413 alone has a problem that it takes a very long distance to obtain a highly uniform mixed state required by the present invention. In this case, spatial and cost disadvantages arise. In order to solve such a problem, it is conceivable to install a baffle plate in the gas flow path. However, this does not only provide a sufficient effect, but also causes a dead space (abnormal stagnation space) to be generated due to the installation. Therefore, there was a problem that side reactions became apparent.

Japanese Patent Publication No. 53-24926 discloses an example of a method of mixing both gases. As a result of studies by the present inventors, especially on an industrial scale, even if this method is used, the gas can be mixed. Since the mixing was insufficient and an abnormal space where the mixed gas was generated, a good yield of methallyl chloride could not be obtained. Further, as a result of detailed examination by the present inventors, it is essential to uniformly disperse both mixed gases in a solvent in order to obtain a good yield of methallyl chloride and achieve industrially stable production. Met. In addition, since this reaction is accelerated by the presence of the liquid film, if a solvent enters the inside of the gas disperser, the reaction rapidly progresses locally there, causing disadvantages in both safety and reaction yield. . Therefore, it has been essential to create a disperser in which no solvent enters into the gas disperser and which can uniformly disperse the gas in the solvent. It is also indispensable not to create an abnormal residence space inside the disperser in order to obtain a good yield of methallyl chloride. However, hitherto, a technique for solving those problems has not been disclosed.

As described above, no suitable technique for uniformly mixing chlorine gas and isobutylene gas has been disclosed, and a barrier to industrially and stably mass-producing methallyl chloride from both gases has been identified. Had become. Further, when using a disperser as a method of dispersing a gas obtained by mixing a chlorine gas and an isobutylene gas in a solvent, a method for uniformly dispersing the gas in the solvent in a state where the gas does not enter the inside of the disperser. Was also not shown.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a method for stably producing methallyl chloride in a high yield by uniformly mixing a chlorine gas and an isobutylene gas and uniformly dispersing the mixed gases in a solvent. It is an object of the present invention to provide a manufacturing method.

[0008]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventors have found that a very uniform mixing state can be achieved by installing a stationary stirring mixer in a gas flow path as a method of mixing both gases. Was found, and since no dead space was generated, side reactions could be significantly suppressed.
Further, by blowing the mixed gas into the solvent through a disperser having a specific structure, uniform dispersion of the gas is achieved, and furthermore, the invasion of the solvent into the disperser is suppressed, and the methallyl chloride can be favorably collected. In addition to being able to manufacture safely at a high rate, instability factors such as entrainment due to gas injection were eliminated, and industrially stable production became possible.

That is, the present invention is as follows. 1) A method for producing methallyl chloride by mixing chlorine gas and isobutylene gas and supplying the mixed gas to a solvent, wherein the supply molar ratio of both gases (isobutylene / chlorine) is 0.9 to 1.
1. A method for producing methallyl chloride, wherein a static stirring mixer is provided in a flow path where both gases are combined.

2) A mixture of chlorine gas and isobutylene gas is supplied to a large number of holes whose diameters and arrangements are adjusted so that gas is discharged from each hole at a uniform flow rate and an abnormal gas stagnation space does not occur inside. 2. The method for producing methallyl chloride according to the above 1, wherein the methallyl chloride is supplied through a disperser having pores. 3) The method for producing methallyl chloride as described in 2 above, wherein the gas discharge holes of the disperser are arranged downward in the solvent.

Hereinafter, the present invention will be described in detail. In the production method of the present invention, the formation reaction of methallyl chloride is:
This is a reaction that proceeds very quickly by mixing chlorine gas and isobutylene gas in the gas phase and supplying the mixed gas into a solvent. As a result of experiments conducted by the present inventors by changing the supply molar ratio of chlorine gas and isobutylene gas and the mixing state of both gases, it was found that the supply molar ratio of both gases was strictly set and both gases were mixed very uniformly. Has been found to be essential in obtaining good yields of methallyl chloride. It is extremely important that the supply molar ratio of both gases is set to a specific range around 1.0.

When the supply molar ratio of chlorine to isobutylene (isobutylene / chlorine) is less than 0.9, that is, when the chlorine is excessive, a higher chlorinated product is produced by further chlorinating the produced methallyl chloride. Is conspicuous, and as a result, the yield of methallyl chloride decreases. On the other hand, when the molar ratio exceeds 1.1, that is, when isobutylene is excessive, not only the obvious disadvantage of lowering the yield of methallyl chloride to isobutylene occurs, but also the chloride produced as a by-product with isobutylene. The amount of t-butyl chloride produced by the reaction with hydrogen increases.
Since the boiling point of t-butyl chloride is close to that of methallyl chloride, an increase in the amount of by-products disadvantageously complicates the separation and purification process. Therefore, the preferable range of the supply molar ratio of chlorine and isobutylene is 0.9 to 0.9.
1.1, and a more preferred range is 0.95-1.
05.

As described above, if the molar ratio of the raw material gases to be supplied is not set strictly, disadvantages such as a pronounced side reaction occur, but even if the molar ratio is set strictly, both gases are extremely low. Unless the mixture is uniformly mixed, a portion deviating from the molar ratio at the time of supply is locally generated, which also causes a problem that a side reaction becomes apparent. In other words, it is essential that the molar ratio of the chlorine gas and the isobutylene gas at the time of supply be strictly controlled within a specific range, and that both gases be mixed very uniformly.

[0014] The stationary stirring mixer used in the present invention is a mixer which does not move by itself, and a good mixing state can be obtained at a very short distance by passing a fluid therethrough, and there is no abnormal stagnation space. It is. Only by installing the mixer in the flow path after the merging of the chlorine gas and the isobutylene gas, a highly uniform mixing state can be obtained, and methallyl chloride can be obtained at a high yield.

As the mixer, for example, “Advance in Chemical Engineering 24, Stirring / Mixing (edited by the Society of Chemical Engineers), p. 155-1
64 ”and“ Liquid mixing technology (Nikkan Kogyo Shimbun) ”p. 157
To 186 "can be used, but a Kenix type mixer is particularly preferable. For example, when this is used, the number of units of the mixer to be installed to uniformly mix both gases is, even under a condition in which the Reynolds number of the gas is less than 2,000, which is called a laminar flow region and is difficult to mix. A uniform mixing state required in the present reaction can be achieved by setting up to 6 units or less. Gas Reynolds number is 20
Under conditions of easy mixing called a turbulent region exceeding 00, the number of units may be further reduced, and 2 to 4 units may be provided. On an industrial scale, the reaction is usually carried out in a region where the Reynolds number of the gas exceeds 10,000, so that a sufficient mixing state can be obtained even with two units.

The method of mixing chlorine gas and isobutylene gas with a stationary stirring mixer is not particularly limited as long as there is no abnormal residence space, but a method using a double pipe or a method using a branch pipe is used. Is simple. FIGS. 1 and 2 show examples of the mode of installation of the stationary stirring mixer used in the present invention. FIG. 1 is a cross-sectional view of a double pipe in which four units of a Kenix-type stationary stirring mixer are installed in a flow path. FIG. 2 is a cross-sectional view of a branch pipe in which four units of a Kenix-type stationary stirring mixer are provided in a flow path. In FIG. 1, reference numerals 1 and 2 denote introduction portions for chlorine gas and isobutylene gas.
The method can be arbitrarily determined. In FIG. 2, reference numerals 3 and 4 denote chlorine gas and isobutylene gas introduction portions, and it is possible to arbitrarily determine which of the gas 3 and 4 is introduced. In FIGS. 1 and 2, reference numerals 5 and 6 denote right-handed and left-handed elements (unit structure) of the Kenix-type stationary stirring mixer, respectively.

In the present invention, the mixing section provided with the static mixer can be cooled by various methods for the purpose of removing the heat of reaction between chlorine and isobutylene. As the method, a general-purpose method such as air cooling or water cooling can be adopted, but a method in which the mixed portion is immersed in a solvent for carrying out the reaction and cooled using the latent heat of evaporation or sensible heat is preferable. It is.

The disperser according to the present invention is a disperser having a large number of pores whose diameter and arrangement are adjusted so that gas is discharged from each hole at a uniform flow rate and an abnormal gas stagnation space does not occur inside. It is. FIGS. 3 and 4 show side and bottom views of an example of the disperser, respectively. In FIGS. 3 and 4, reference numeral 7 denotes an inlet for a mixed gas of chlorine gas and isobutylene gas. Reference numerals 8 and 9 denote flow paths for the gas. Reference numeral 10 denotes a plurality of source gas discharge holes provided in the gas flow path, which are arranged so that the gas is discharged downward. With such a structure, uniform dispersion of the source gas in the solvent is achieved.

The disperser is very effective especially in an industrial scale reaction where the flow rate of the raw material gas is large. If it is not installed, the rate at which the raw material gas supplied into the solvent escapes unreacted from the solvent in the form of huge bubbles increases, and the yield of methallyl chloride is greatly reduced. In addition, there is a problem that the entrainment of the solvent into the supplied raw material gas becomes remarkable and stable operation becomes difficult.

In the present invention, the disperser is immersed in a solvent and supplies the raw material gas into the solvent. At this time, it is preferable that the disperser is installed so that the gas discharge holes of the disperser are arranged downward. preferable. Otherwise, the solvent enters the interior of the disperser during the reaction, and as a characteristic of the present reaction, a sudden reaction occurs locally, which is likely to cause problems in safety and reaction yield.

The solvent used in the present invention is not particularly limited, and a common organic solvent or water can be used. However, a substance which is inactive against chlorine and isobutylene, for example, hexachloro-1-methylbenzene , 3-butadiene and tetrachloroethylene are preferred. However, when such a solvent is used, it is necessary to separate the product from the product, which disadvantageously complicates the process. Therefore, a mixture mainly composed of methallyl chloride resulting from the reaction (hereinafter referred to as a product). Liquid) is most preferably used.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically and in detail based on embodiments. The analysis of the products in Examples and Comparative Examples was carried out using a gas chromatograph under the following conditions. The results are shown in yield (%) based on the supplied isobutylene. (Product analysis method) [Gas chromatograph] Shimadzu GC-14B, [Column]
Silicon DC-550, [oven] 60 ° C hold 5 minutes,
Temperature rise 5 ° C / min, hold at 210 ° C for 10 minutes, [injector, detector] 210 ° C

[0023]

Example 1 In a double tube system (system of FIG. 1) in which two units of a Kenix type static stirring mixer were installed in a channel having an inner diameter of 5 mm, chlorine 420 cc / min (0 ° C. conversion) and isobutylene 410 cc / min (In terms of 0 ° C.), and the mixture was supplied from a side surface of a reactor (φ35 × 100 mm) equipped with a reflux condenser into a product liquid in the reactor to carry out a reaction.

The product liquid was continuously withdrawn, and the amount of the product liquid in the reactor was always maintained at 40 cc. The temperature of the product liquid in the reactor was maintained at 60 ° C. The product liquid continuously extracted from the reaction liquid and the exhaust gas from the reflux cooler were introduced into water to absorb by-product hydrogen chloride. The product liquid and exhaust gas after absorption of hydrogen chloride were analyzed by gas chromatography to determine the reaction yield. The results are shown below.

84.6% of methallyl chloride, 1.0% of t-butyl chloride, 3.3 of isocrotyl chloride
%, 1,2-dichloroisobutane 5.5%, 1-chloro-2-chloromethyl-1-propene 1.5%, 3-chloro-2-chloromethyl-1-propene 2.3%, 1,
1.5% 2,3-trichloroisobutane, other 0.3
%.

Example 1 satisfies the essential requirements of the present invention, so that methallyl chloride is obtained in good yield.

[0027]

Example 2 A reaction was carried out under the same conditions as in Example 1 except that the number of units of the Kenix-type static stirring mixer provided in the flow path was changed to 4 units. The reaction yield is shown below. 85.6% methallyl chloride, t-butyl chloride 1.
0%, isocrotyl chloride 3.3%, 1,2-dichloroisobutane 5.4%, 1-chloro-2-chloromethyl-1-propene 1.3%, 3-chloro-2-chloromethyl-1 1.9% propene, 1.2% 1,2,3-trichloroisobutane, 0.2% other.

Example 2 satisfies the essential requirements of the present invention, and methallyl chloride is obtained in a good yield.

[0029]

Example 3 A reaction was carried out under the same conditions as in Example 1 except that the number of units of the Kenix type static stirring mixer provided in the flow path was changed to 6 units. The reaction yield is shown below. 85.6% methallyl chloride, t-butyl chloride 1.
0%, isocrotyl chloride 3.3%, 1,2-dichloroisobutane 5.4%, 1-chloro-2-chloromethyl-1-propene 1.2%, 3-chloro-2-chloromethyl-1 1.9% propene, 1.2% 1,2,3-trichloroisobutane, 0.2% other.

Example 3 satisfies the essential requirements of the present invention, so that methallyl chloride is obtained in good yield.

[0031]

Comparative Example 1 A reaction was carried out under the same conditions as in Example 1 except that no mixer was provided in the flow channel. The reaction yield is shown below. Methallyl chloride 55.2%, t-butyl chloride 10.2%, isocrotyl chloride 3.0
%, 1,2-dichloroisobutane 5.1%, 1-chloro-2-chloromethyl-1-propene 6.1%, 3-chloro-2-chloromethyl-1-propene 9.4%, 1,
6.9% of 2,3-trichloroisobutane, other 4.2
%.

In Comparative Example 1, since a stationary stirring mixer, which is an essential requirement of the present invention, was not installed, the mixing state of chlorine gas and isobutylene gas was poor, and the yield of methallyl chloride was poor. It is.

[0033]

Embodiment 4 In a double tube system (system of FIG. 1) in which 4 units of a Kenix type static stirring mixer are installed in a flow path having an inner diameter of 25 mm, chlorine 20.4 m ³ / Hr (converted to 0 ° C.) and isobutylene 20.0 m ³ / min (converted to 0 ° C.), and a reactor equipped with a reflux cooler (φ300 mm × 800 m) through a disperser of the type shown in FIG.
The reaction was carried out by feeding into the product liquid in m).

The product liquid was continuously withdrawn, and the amount of the product liquid in the reactor was always maintained at 0.06 m3. The temperature of the product liquid in the reactor was maintained at 60 ° C. The product liquid continuously extracted from the reaction liquid and the exhaust gas from the reflux cooler were introduced into water to absorb by-product hydrogen chloride. The product liquid and exhaust gas after absorption of hydrogen chloride were analyzed by gas chromatography to determine the reaction yield. The results are shown below.

85.2% of methallyl chloride, 0.8% of t-butyl chloride, 3.3 of isocrotyl chloride
%, 1,2-dichloroisobutane 5.3%, 1-chloro-2-chloromethyl-1-propene 1.5%, 3-chloro-2-chloromethyl-1-propene 2.3%, 1,
1.4% 2,3-trichloroisobutane, other 0.2
%.

Example 4 satisfies the essential requirements of the present invention, so that methallyl chloride is obtained in a good yield. In addition, stable operation without abnormal heat generation and abnormal reaction is realized.

[0037]

Comparative Example 2 The reaction was carried out under the same conditions as in Example 4 except that the raw material gas was supplied from the side of the reactor into the product liquid without installing a stationary stirring mixer and a disperser. did. The results are shown below. Methallyl chloride 43.2
%, T-butyl chloride 12.1%, isocrotyl chloride 3.0%, 1,2-dichloroisobutane 7.2
%, 1-chloro-2-chloromethyl-1-propene8.
3%, 3-chloro-2-chloromethyl-1-propene 1
1.2%, 1,2,3-trichloroisobutane 8.7
%, Others 6.3%.

In Comparative Example 2, since a stationary stirring mixer, which is an essential requirement of the present invention, was not installed, the mixing state of chlorine gas and isobutylene gas was poor, and the yield of methallyl chloride was poor. It is. Further, since no disperser is provided, the poor dispersion state of the raw material gas in the product liquid also causes a decrease in yield. Furthermore, since the disperser was not installed, the generated gas was significantly entrained by the raw material gas, and stable operation was often difficult.

[0039]

According to the present invention, it is possible to simultaneously obtain a good mixed state of chlorine gas and isobutylene gas and to uniformly disperse the mixed raw material gas in the product liquid. As a result, various chemical products can be obtained. It is possible to stably produce methallyl chloride, which is useful as a raw material or an intermediate of, on an industrial scale.

[Brief description of the drawings]

FIG. 1 is an example of an embodiment in which a stationary stirring mixer used in the present invention is installed in a flow path of a raw material gas.

FIG. 2 is an example of an embodiment in which a stationary stirring mixer used in the present invention is installed in a flow path of a raw material gas.

FIG. 3 is a side view of an example of the disperser used in the present invention.

FIG. 4 is a bottom view of an example of the disperser used in the present invention.

[Explanation of symbols]

1 Introducing section of chlorine gas and isobutylene gas 2 Introducing section of chlorine gas and isobutylene gas 3 Introducing section of chlorine gas and isobutylene gas 4 Introducing section of chlorine gas and isobutylene gas 5 Right-handed element of Kenix type static stirring mixer 6 Left-handed element of Kenix type static stirring mixer 7 Introduction section of mixed gas of chlorine gas and isobutylene gas 8 Flow path of mixed gas of chlorine gas and isobutylene gas 9 Flow path of mixed gas of chlorine gas and isobutylene gas 10 Raw material Gas outlet

Claims (3)

[Claims] 1. A method for producing methallyl chloride by mixing chlorine gas and isobutylene gas and supplying the mixed gas to a solvent, wherein the supply molar ratio of both gases (isobutylene / chlorine) is 0.9 to 1.1. A method for producing methallyl chloride, wherein a static stirring mixer is provided in a flow path where both gases are combined. 2. A gas mixture of a chlorine gas and an isobutylene gas is supplied to a plurality of holes whose diameters and arrangements are adjusted so that gas is discharged from each hole at a uniform flow rate and an abnormal gas stagnation space does not occur inside. The method for producing methallyl chloride according to claim 1, wherein the methallyl chloride is supplied through a disperser having pores. 3. The method for producing methallyl chloride according to claim 2, wherein the gas discharge holes of the disperser are arranged downward in the solvent.