JP2010241689A - Method for producing chlorohydrin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing chlorohydrin, by which the chlorohydrins can safely, industrially and efficiently be produced with a low cost and simple reactor. <P>SOLUTION: This method for producing the chlorohydrin, comprising reacting a 2 to 4C hydrocarbon having two or more hydroxy groups with hydrogen chloride in a liquid phase to substitute the hydroxy group of the hydrocarbon with chlorine, includes dispersing the hydrogen chloride in the liquid phase as fine bubbles having an average diameter of ≤1,000 μm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing chlorohydrin useful as an industrial intermediate.

  Chlorohydrin, which is a hydrocarbon having a chlorine atom and a hydroxyl group in the molecule, is an intermediate for producing polyether polyols, glycol ethers, epoxy compounds, or other useful substances, and is an industrially important compound. As a method for producing chlorohydrin, a method in which chlorine and water are reacted to produce hypochlorous acid, and the produced hypochlorous acid and a double bond-containing hydrocarbon are reacted is conventionally known. However, since a large amount of a halogen-containing compound is produced as a by-product in this method, a production method with less environmental load has been desired.

  In recent years, as a method for producing chlorohydrin, a reaction between a polyhydric alcohol such as glycerin obtained from renewable resources such as agricultural crops and hydrogen chloride has been proposed. However, this production method does not always satisfy the reaction rate, selectivity, reaction rate, and the like, and attempts have been made to solve the above problems for industrial applications. For example, in (a) Patent Document 1, the reaction is carried out while removing the water produced by the reaction between the polyhydric alcohol and hydrogen chloride, thereby moving the equilibrium to the production system and improving the reaction rate, reaction rate, etc. want to be. (B) In Patent Document 2, by increasing the partial pressure of hydrogen chloride in the system, the reaction rate is improved along with the reduction of impurities produced. (C) Furthermore, Patent Document 2 and Patent Document 3 disclose a method using a special catalyst.

  However, each of the above methods has the following problems.

  In the case of (a), in order to remove water generated in the reaction system, it is necessary to install a device such as a distillation tower directly connected to the reaction vessel. Alternatively, there is a method of installing an apparatus for removing water in the middle of carrying out the reaction in several stages, both of which are unpreferable for use in an industrial plant because of the equipment cost and operation cost of the process.

  In the case of (b), it is not necessary to remove water as in (b), but in order to obtain a sufficient yield, it is industrially satisfactory unless the pressure is at least 0.65 MPa (absolute pressure). You can't get results. In addition, it is necessary to use a pressure resistant device for both the supply equipment and reaction vessel for the hydrogen chloride as a raw material, which is not preferable from the viewpoint of safety as well as the equipment cost.

  In the case of (c), the production cost increases because the catalyst used is expensive. Although it is conceivable to recover and reuse the catalyst, a separate catalyst recovery step is required, which is not preferable from the viewpoint of process equipment cost and energy cost.

International Publication No. 2005/021476 Pamphlet International Publication No. 2006/020234 Pamphlet International Publication No. 2005/054167 Pamphlet

  In view of the above problems, an object of the present invention is to provide a method for industrially producing chlorohydrin safely and efficiently using an inexpensive and simple reaction apparatus.

  As a result of intensive studies to solve the above problems, the inventors of the present invention have made it possible to shorten chlorohydrin with high reaction rate and high selectivity by dispersing hydrogen chloride as fine bubbles having an average diameter of 1000 μm or less in the liquid phase. They found that they could be manufactured in time, and completed the invention.

That is, the following (1) to (9) of the present invention are provided.
(1) A method for producing chlorohydrin in which a hydrocarbon having 2 or more hydroxyl groups and a hydrocarbon having 2 to 4 carbon atoms and hydrogen chloride are reacted in a liquid phase to replace the hydroxyl group of the hydrocarbon with chlorine, A method for producing chlorohydrin, wherein the hydrogen chloride is dispersed as fine bubbles having an average diameter of 1000 μm or less.
(2) The method for producing chlorohydrin according to (1), wherein the liquid phase is a saturated solution of hydrogen chloride.
(3) The method for producing chlorohydrin according to (1) or (2), wherein the hydrocarbon having 2 to 4 carbon atoms having 2 or more hydroxyl groups is glycerin or monochloropropanediol.
(4) The method for producing chlorohydrin according to (3), wherein the chlorohydrin is 1,3-dichloro-2-propanol.
(5) The method for producing chlorohydrin according to any one of (1) to (4), wherein the reaction is performed in the presence of a catalyst.
(6) The method for producing chlorohydrin according to any one of (1) to (5), wherein the hydrogen chloride is dispersed by being introduced into the liquid phase through fine pores.
(7) The hydrogen chloride is dissolved in a hydrocarbon having 2 to 4 carbon atoms having two or more hydroxyl groups under pressure, supplied to a reaction vessel, and precipitated in the reaction vessel. The method for producing chlorohydrin according to any one of (1) to (6), wherein the method is dispersed.
(8) The method for producing chlorohydrin according to (1) to (7), wherein the hydrogen chloride contained in the fine bubbles is 0.01 to 10 times the hydrogen chloride dissolved in the liquid phase. .
(9) The method for producing a chlorohydrin according to any one of (1) to (8), further comprising a step of recovering and reusing hydrogen chloride from the solution after the reaction.

  The present invention provides a method for industrially producing chlorohydrin safely and efficiently using an inexpensive and simple reaction apparatus. In particular, in the present invention, since the pressure in the reaction vessel can be lowered, it is not necessary to use a large and multi-layer pressure-resistant device, which is preferable from the viewpoint of equipment cost.

  The C2-C4 hydrocarbon having two or more hydroxyl groups used in the present invention is a compound in which two or more hydrogen atoms of a C2-C4 hydrocarbon are substituted with hydroxyl groups. The hydrocarbon may be linear or branched and may contain a double bond.

  As for the C2-C4 hydrocarbon which has two or more of the said hydroxyl groups, a part of hydrogen may be substituted by chlorine. Hereinafter, the C2-C4 hydrocarbon having two or more hydroxyl groups is referred to as the present polyol.

  Examples of the polyol include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2,3-propanetriol (hereinafter also referred to as glycerin), 1,2-butanediol, Monochlorodipropanol such as 1,3-butanediol, 1,4-butanediol, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, and mixtures thereof . Among these, 3-chloro-1,2-propanediol, 2-chloro-1,3-propanediol, 1,2,3-propanetriol, 1,2-propanediol, and 1,3-propanediol Particularly preferred. Specifically, glycerin obtained as a by-product of biodiesel fuel is preferably exemplified.

  When the present invention is carried out using, for example, glycerin as the polyol, 3-chloro-1,2-propanediol or 2-chloro-1,3-propanediol (hereinafter referred to as monochrome) in which one of the hydroxyl groups is replaced with chlorine. 1,3-dichloro-2-propanol or 2,3-dichloro-1-propanol (hereinafter also referred to as dichlorohydrin) in which two of the hydroxyl groups are replaced by chlorine is obtained. In the production method of the present invention, glycerin to dichlorohydrin can be obtained in one step, but the production method of the present invention is adopted in the step of obtaining monochlorohydrin from glycerin or the step of obtaining dichlorohydrin from monochlorohydrin. You can also

  This polyol has at least two hydroxyl groups, and part or all of them may be ester groups. Moreover, even if all the hydroxyl groups are ester groups, they can be applied to the present invention when they are hydrolyzed to become hydroxyl groups in the reaction with hydrogen chloride described later. In addition, the said ester group is group which consists of a hydroxyl group and the carboxyl group of carboxylic acid. The ester group may be formed when carboxylic acid is used as a catalyst described later.

  In addition, when a part or all of the hydroxyl group is an ester group in the reaction product, it can be hydrolyzed by a usual method to obtain the target chlorohydrin.

  The hydrogen chloride used in the present invention is more likely to react as the water content is smaller, so the water content is preferably as small as possible. The water content is usually 50% by mass or less, preferably 10% by mass or less.

  Next, this reaction will be described. This reaction is a process for producing the target chlorohydrin by reacting the polyol and hydrogen chloride in a liquid phase.

  The chlorohydrin obtained by this reaction is a C2-C4 hydrocarbon containing at least one hydroxyl group and one chlorine atom in the molecule. Specifically, 1-chloro-2-ethanol, 1-chloro-2-propanol, 2-chloro-1-propanol, 3-chloro-1-propanol, 3-chloro-1,2-propanediol, 2- Chloro-1,3-propanediol, 2,3-dichloro-1-propanol, 1,3-dichloro-2-propanol, 1-chloro-2-butanol, 2-chloro-1-butanol, 1-chloro-3 -Butanol, 3-chloro-1-butanol, 4-chloro-1-butanol and the like are preferable, and 1,3-dichloro-2-propanol is particularly preferable. The hydroxyl group of the chlorohydrin may be an ester group. The ester group is a group consisting of a hydroxyl group and a carboxyl group of a carboxylic acid.

  This reaction may be carried out in the presence of a catalyst or in the absence of a catalyst, but addition of a catalyst is preferred from the viewpoint of shortening the reaction time. As the catalyst, known ones can be used. Specifically, carboxylic acid compounds such as formic acid, acetic acid, propionic acid and adipic acid, and carboxylic acid-containing polymers such as polyacrylic acid and acrylic acid-ethylene copolymer. And mixtures thereof. Among these, formic acid, acetic acid, propionic acid and the like are preferable. These are advantageous from an economic point of view. The purity for industrial use is sufficient, but for the same reason as hydrogen chloride, the water content is preferably as low as possible.

  The addition amount of the catalyst is 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the present polyol. When the amount is less than 0.1 parts by mass, the reaction time is long. When the amount is more than 20 parts by mass, the yield of by-products increases. The method for adding the catalyst is not particularly limited, but it is possible to add the whole amount from the beginning of the reaction or to add it in the middle of the reaction.

  The reaction temperature is usually 30 to 180 ° C, preferably 50 to 150 ° C, particularly preferably 80 to 120 ° C. When it is lower than 30 ° C., the reaction rate is slow, which is not preferable from an industrial viewpoint. When the temperature is higher than 180 ° C., the yield decreases due to thermal decomposition of the product chlorohydrin.

  Since the reaction rate increases as the pressure increases, the pressure is usually 0.05 MPa (absolute pressure) or higher, preferably 0.1 MPa (absolute pressure) or higher, more preferably 0.15 MPa (absolute pressure) or higher. The upper limit of the pressure is determined from the viewpoint of the apparatus, and usually 1.0 MPa (absolute pressure) or less, preferably 0.6 MPa (absolute pressure) or less is employed. When the pressure is greater than 1.0 MPa (absolute pressure), a multi-layer pressure-resistant facility is required.

  The amount of hydrogen chloride contained as fine bubbles in the liquid phase is usually 0.01 to 10 times, preferably 0.03 to 1 times that of hydrogen chloride dissolved in the liquid phase. When it is less than 0.01 times, there are almost no hydrogen chloride bubbles in the reaction vessel, and the reaction rate is slow. When it is more than 10 times, the amount of hydrogen chloride to be recovered increases, which is uneconomical. The amount of hydrogen chloride dissolved in the liquid phase can be determined by a known method.

  The optimum reaction time is appropriately determined depending on the supply amount of hydrogen chloride, the liquid phase composition, and the like, but in the case of a batch process, it is usually 1 to 10 hours, preferably 2 to 5 hours.

  In this reaction, the method of dispersing hydrogen chloride fine bubbles in the liquid phase is not particularly limited. <1> Method of introducing hydrogen chloride through fine pores, <2> Method of supersaturated precipitation, <3> Bubbles And a method using <4> turbulent stirring. These may be used alone or in combination of two or more. Among these, <1> a method of introducing through fine pores and <2> a method of supersaturated precipitation are preferable in that hydrogen chloride having a high concentration can be supplied as fine bubbles having a controlled size. Each method will be described in detail below.

  <1> The method of introducing hydrogen chloride through micropores is a method of supplying hydrogen chloride from the micropores into the reaction liquid phase as microbubbles. Specifically, a member having fine holes such as a net, a fine plate, or a porous object is attached to the tip of the nozzle, and hydrogen chloride is supplied into the system as fine bubbles through the nozzle. The diameter of the micropores is 0.05 to 100 μm, preferably 0.05 to 50 μm, and more preferably 0.05 to 1 μm. When it is smaller than 0.05 μm, a large pressure is applied to the introduction of hydrogen chloride. When it is larger than 100 μm, the obtained bubbles become large. Although the number of nozzles may be one or plural, it is preferable to arrange them in a positional relationship such that bubbles do not coalesce. The shape of the nozzle tip is not particularly limited, and examples thereof include a circular shape and an elliptical shape. The material of the member having fine holes may be any material that is not corroded by hydrogen chloride, and glass is particularly suitable.

  The supersaturated precipitation method <2> is a method in which hydrogen chloride is dissolved in the present polyol under pressure and supplied to a reaction vessel, and hydrogen chloride that has been excessively dissolved due to changes in temperature and pressure is generated as fine bubbles.

  The method of crushing bubbles in <3> is a method of cleaving and subdividing hydrogen chloride bubbles in a reaction liquid phase into fine bubbles using a known method such as ultrasonic waves.

  <4> The method using turbulent agitation is a method in which the liquid phase from which hydrogen chloride bubbles are released is jetted using a stirrer, swirling, etc., and the bubbles are crushed and fined by the shear force between the liquid and liquid. Or bubbles are pulverized and refined by collision with a vessel wall / protrusion or the like.

  The average diameter of hydrogen chloride fine bubbles is usually 1000 μm or less, preferably 500 μm, more preferably 1 μm. When the average diameter exceeds 1000 μm, the reaction rate decreases. The maximum diameter of the fine bubbles is 2000 μm or less, preferably 1000 μm or less. The number of fine bubbles having a diameter of 500 μm or less is preferably 50% or more of all fine bubbles. In addition, when a bubble is a flat spherical shape, let the major axis be the said diameter.

  The diameter of the fine bubbles can be determined by taking a photograph from a transparent window provided in a part of the reaction container (or an arbitrary place when the whole reaction container is transparent) and analyzing the photograph image. Alternatively, it can also be obtained by sampling the liquid in the reaction vessel, confining it in a transparent vessel, and observing under a microscope within 1 minute from the sampling. In addition, the said transparent window can be provided in the arbitrary places of reaction container. The average diameter of the fine bubbles is a value obtained by measuring the diameters of the fine bubbles in the photographic image and averaging the values. It is desirable that the number of fine bubbles measured to obtain the average value is as large as possible. In terms of reproducibility, the number of randomly selected fine bubbles is usually 10 or more, preferably 20 or more, more preferably 50 or more. As a typical example, at least two or more photographs are taken, the diameters of 1000 or more fine bubbles in each photographic image are measured, and the average value is obtained. The average diameter can be calculated by statistically processing an image with commercially available image processing software. The measurement lower limit of fine bubbles is usually 50 μm due to problems with the apparatus such as the resolution of photographs.

  The reaction vessel is not particularly limited, and a known reaction vessel can be used. Moreover, the reaction system is not particularly limited, and may be either batch type or continuous type. From the viewpoint of industrial use, the continuous type is preferred. Note that the reaction vessel only needs to secure a residence time necessary for the reaction, and it is not necessary to use an expensive apparatus provided with multi-layer pressure resistance.

  In the production method of the present invention, chlorohydrin can be produced with a high reaction rate and high selectivity in a very short time by dispersing hydrogen chloride as fine bubbles having an average diameter of 1000 μm or less. Although the details of the reason for this effect are unknown, it is considered that one of the reasons is that the surface area per unit volume of the fine bubbles is extremely large. In other words, since the dissolution of hydrogen chloride from the gas phase to the liquid phase is carried out through the interface between both phases, it is assumed that the dissolution of hydrogen chloride in the liquid phase was greatly promoted by increasing the surface area of the hydrogen chloride bubbles. Is done. Therefore, the reaction rate can be increased even when the pressure is not high, and the reaction can be carried out with an inexpensive and simple reaction apparatus. Note that, under the conditions of the prior art (Patent Documents 1, 2 and 3), it is presumed that almost no fine bubbles are generated in the reaction system, and the effect of the present invention cannot be obtained.

  The reaction rate and selectivity to chlorohydrin obtained by the production method of the present invention vary depending on the raw material composition, reaction conditions, etc., but typically the reaction rate is 90% or more, preferably 95% or more, more preferably 99% or more. The selectivity is 80 mol% or more, preferably 85 mol% or more, more preferably 90 mol% or more. The reaction rate and selectivity were calculated from the peak areas of each component obtained by gas chromatography analysis.

  Even in cases other than the method of <2> supersaturated precipitation, it is preferable to provide a step of absorbing hydrogen chloride into the polyol (hereinafter referred to as an absorption step) before the above-described reaction step. In particular, it is more preferable to obtain a saturated solution in which hydrogen chloride is dissolved to the saturation solubility by this step.

  The temperature in an absorption process is 0-150 degreeC normally, Preferably it is 20-100 degreeC. When the temperature is lower than 0 ° C., the viscosity of the liquid phase increases and the dissolution efficiency of hydrogen chloride decreases. When the temperature is higher than 150 ° C., the amount of dissolved hydrogen chloride decreases, and the reaction efficiency similarly decreases.

  The absorption step may be either in a solvent or in the absence of a solvent, but is preferably in the absence of a solvent from the viewpoint of simplification of the process. In addition, when using a solvent, ethylene dichloride etc. can be used, for example. The amount of the solvent used is appropriately selected depending on the reaction scale and the reaction apparatus.

  The apparatus in an absorption process is not specifically limited, Well-known things, such as a venturi, an ejector, a mixer, a pump, an absorption tower, are used. Examples of the absorption tower include a packed tower, a spray tower, a bubble tower, and a wet wall tower. Moreover, you may implement an absorption process and a reaction process with the same reaction container. The absorption process can be batch-wise or continuous, but the continuous method is industrially advantageous.

  It is desirable to select various conditions so that the saturated solubility of hydrogen chloride under the pressure and temperature conditions in the absorption process is higher than the saturated solubility of hydrogen chloride under the pressure and temperature conditions in the reaction process. By having this condition, the hydrogen chloride dissolved in this step is likely to appear as fine bubbles in the reaction step.

  In this invention, the process of pressurizing and heating the liquid phase obtained after the absorption process may be included as needed. The pressurizing pressure is usually 0.1 to 1.0 MPa (absolute pressure), preferably 0.2 to 0.6 MPa (absolute pressure). Desirably higher than the pressure in the reaction process. As the pressurizing method, a known method such as a pump can be used. The heating temperature is usually 30 to 150 ° C, preferably 80 to 120 ° C. In addition, it is desirable to pressurize to the pressure which can maintain the saturated state of hydrogen chloride under the heating conditions.

  In the present invention, if necessary, a part of the reaction solution obtained in the reaction step may be taken out and circulated to the absorption step. The amount of the reaction liquid to be circulated is appropriately selected depending on the implementation scale, the reaction apparatus, and the like. Part by mass. The temperature of the circulated reaction solution is usually 0 to 150 ° C, preferably 20 to 120 ° C. The supply speed of the circulated reaction liquid to the absorption step is appropriately selected depending on the implementation scale, the reaction apparatus, and the like. By circulating the reaction solution, the utilization rate of hydrogen chloride in the reaction step can be increased.

  In this invention, the process of collect | recovering unreacted hydrogen chloride from the reaction liquid obtained at the reaction process as needed, and reusing at an absorption process may be included. The method for recovering hydrogen chloride from the reaction solution is not particularly limited, and known methods such as distillation and extraction can be used. For example, unreacted hydrogen chloride dissolved by heating the reaction solution can be recovered. If hydrogen chloride can be recovered and reused, disposal costs can be reduced and the environmental burden can be reduced.

  The method for recovering the target chlorohydrin from the reaction solution is not particularly limited, and known methods such as distillation and solvent extraction can be used. In particular, a distillation operation is preferred. Although the kind of distillation tower is not specifically limited, For example, a packed tower, a plate tower, etc. are mentioned. The distillation may be either a batch type or a continuous type, but a continuous type is preferred industrially.

  The obtained chlorohydrin can be further purified to a high purity by a general method such as distillation, crystallization, or extraction, if necessary.

  The manufacturing process of the present invention will be described with reference to the drawings. FIG. 1 is a process schematic illustrating one embodiment of the present invention. Note that the present invention is not limited to this.

  The starting polyol is continuously fed from line 1 and hydrogen chloride from line 2A to hydrogen chloride absorption tower A. This polyol containing hydrogen chloride is withdrawn from line 3 as the bottom liquid of the hydrogen chloride absorption tower. A catalyst is supplied from the line 4 and mixed with the present polyol, and supplied from the line 5 to the reaction tower B by an absorption liquid pump. Hydrogen chloride is supplied to the reaction tower B from the line 2B. At this time, the nozzle is selected to generate hydrogen chloride fine bubbles to carry out the reaction. After completion of the reaction, a part of the reaction solution is circulated from the line 6 to the hydrogen chloride absorption tower. The reaction liquid is supplied to the hydrogen chloride recovery tower through line 7 and excess hydrogen chloride is extracted from line 8 at the top of the tower and reused in the hydrogen chloride absorption tower. The reaction liquid from which excess hydrogen chloride has been removed is supplied from line 9 to the distillation column. The target chlorohydrin is distilled from line 10. On the other hand, the distillation residue is extracted from the line 11.

  FIG. 2 is a process conceptual diagram showing another embodiment of the present invention. In FIG. 2, there is no hydrogen chloride absorption tower of FIG. 1, and hydrogen chloride is mixed with the present polyol and compressed immediately before the pump P. In this state, since the pressure is high, hydrogen chloride is dissolved in the polyol at a saturation concentration or higher at normal pressure. The polyol introduced into the low-pressure reaction vessel B from the line 5 is precipitated as fine bubbles in the reaction vessel B because hydrogen chloride is supersaturated.

  The present invention will be described in more detail with reference to the following examples, but the present invention is not limited by these examples.

  About Examples 1-6, it implemented with the apparatus shown next. A 1 L glass autoclave equipped with a stirrer, thermometer, pressure gauge, hydrogen chloride blowing nozzle into the liquid phase, pressure control valve, and liquid phase sampling nozzle was used. A heater is attached to the outer surface of the autoclave. The reaction temperature was controlled by the heater current of the temperature controller. The reaction pressure was controlled manually by a pressure control valve. A hydrogen chloride blowing nozzle and a liquefied hydrogen chloride cylinder (purity 99.7% or more) were connected, a hydrogen chloride rotor meter and a needle valve were installed in the middle, and the supply amount of hydrogen chloride was controlled by adjusting the needle valve. Porous glass was attached to the tip of the hydrogen chloride blowing nozzle. In addition, a reaction solution was appropriately collected from the liquid phase sampling nozzle during the reaction.

Example 1
300 g of glycerin (purity 99.9%) and 6 g of acetic acid were charged into an autoclave and sealed, and the stirrer was operated. Hydrogen chloride was introduced at 4 Nl / min for 1 hour to obtain a saturated solution of hydrogen chloride. The introduction of hydrogen chloride was temporarily stopped, the pressure in the reaction vessel was adjusted to 0.15 MPa (absolute pressure), and the temperature in the reaction vessel was raised to 100 ° C. in 30 minutes. When the temperature reached 100 ° C., hydrogen chloride was again introduced at 4 Nl / min. In addition, the reaction liquid is sampled from the liquid phase sampling nozzle every predetermined time with this time as the start of the reaction, and the reaction rate of glycerin and 1,3-dichloro-2-propanol which is the target substance by gas chromatography and The selectivity to 2,3-dichloro-1-propanol was analyzed. Moreover, when a photograph was taken from the outside of the autoclave, image analysis was performed and hydrogen chloride bubbles introduced into the reaction vessel were measured, the bubbles had a diameter of 50 to 1000 μm and an average diameter of 700 μm. The reaction rate and selectivity are shown in Table 1 and Table 2, respectively.

Example 2
Each operation was performed under the same conditions as in Example 1 except that the supply amount of hydrogen chloride was 6 Nl / min. The hydrogen chloride bubbles had a diameter of 50 to 1000 μm and an average diameter of 400 μm. The reaction rate and selectivity are shown in Table 1 and Table 2, respectively.

Example 3
Each operation was performed under the same conditions as in Example 1 except that the supply amount of hydrogen chloride was 6 Nl / min and the reaction pressure was 0.2 MPa (absolute pressure). The hydrogen chloride bubbles had a diameter of 50 to 1000 μm and an average diameter of 400 μm. The reaction rate and selectivity are shown in Table 1 and Table 2, respectively.

Example 4
When the operation for obtaining a saturated solution of hydrogen chloride was completed, the stirrer was stopped, and each operation was performed under the same conditions as in Example 3 except that the reaction was performed without restarting the stirrer. The hydrogen chloride bubbles had a diameter of 50 to 1000 μm and an average diameter of 500 μm. The reaction rate and selectivity are shown in Table 1 and Table 2, respectively.

Example 5
Each operation was carried out under the same conditions as in Example 2 without attaching porous glass to the hydrogen chloride blowing nozzle. The hydrogen chloride bubbles had a diameter of 500 to 8000 μm and an average diameter of 4000 μm. The reaction rate and selectivity are shown in Table 1 and Table 2, respectively.

Example 6
Each operation was carried out under the same conditions as in Example 3 without attaching porous glass to the hydrogen chloride blowing nozzle. The hydrogen chloride bubbles had a diameter of 500 to 5000 μm and an average diameter of 3000 μm. The reaction rate and selectivity are shown in Table 1 and Table 2, respectively.

反応率は、グリセリン及び反応中間体のモノクロロプロパノール消失量から求めた。なお、表中−印は測定していないことを意味する。 Table 1 (Reaction rate)

The reaction rate was calculated | required from the monochloropropanol disappearance amount of glycerol and the reaction intermediate. In the table, “-” means that measurement was not performed.

選択率はグリセリンが目的物である１，３−ジクロロ−２−プロパノールまたは２，３−ジクロロ−１−プロパノールに転換された割合（モル％）を表している。なお、表中−印は測定していないことを意味する。 Table 2 (selectivity)

The selectivity represents a ratio (mol%) in which glycerin is converted into 1,3-dichloro-2-propanol or 2,3-dichloro-1-propanol which is the target product. In the table, “-” means that measurement was not performed.

  In Tables 1 and 2, as shown in Examples 1 to 4, it was possible to obtain chlorohydrin which was the target product in a very short time and with high selectivity. In Examples 5 and 6 in which the average diameter of hydrogen chloride fine bubbles is large, the reaction proceeds but takes a long time, and the selectivity is low.

  Into a 5 L glass autoclave, 2,000 g of glycerin (purity 99.9%) and 40 g of acetic acid were charged, sealed, and a stirrer and a pump were operated. The 5 L autoclave was cooled with a jacket, and the content liquid temperature was controlled at 30 ° C. The pump was operated, and hydrogen chloride was introduced from the pump suction at a flow rate of 20 Nl / min for 1 hour. The pressure in the 5 L autoclave was adjusted to 0.6 MPa (absolute pressure) with a pressure control valve. Maintain the pressure at 0.6 MPa (absolute pressure) in a 1 liter autoclave (transparent and visible inside) in which glycerin in which hydrogen chloride is dissolved is previously pressurized to 0.6 MPa (absolute pressure) with hydrogen chloride. However, about 700 ml of liquid was fed with a pump. After completion of liquid feeding, the temperature of the content liquid of the 1 L autoclave was raised to 100 ° C. in 1 hour while maintaining the pressure at 0.6 MPa (absolute pressure). When the temperature reached 100 ° C., the pressure was reduced to 0.3 MPa (absolute pressure) in 2 hours using a pressure control valve provided in the gas layer. The microbubbles generated at this time were photographed from the outside of the 1 L autoclave and analyzed by image analysis. The diameter of the bubbles was 50 μm or less. Furthermore, after reacting at a temperature of 100 ° C. and a pressure of 0.3 MPa for 2 hours, the reaction rate of glycerin and 1,3-dichloro-2-propanol or 2,3-dichloro-1- When the selectivity of propanol was measured, the reaction rate was 99.9% and the selectivity was 93.1%.

  According to the present invention, chlorohydrin can be industrially produced safely and efficiently using an inexpensive and simple reaction apparatus. In particular, in the present invention, since hydrogen chloride having a low pressure can be used, it is not necessary to use a large and multi-layer pressure-resistant device, which is preferable from the viewpoint of construction cost.

FIG. 1 is a process schematic illustrating one embodiment of the present invention. FIG. 2 is a process schematic illustrating another aspect of the present invention.

Explanation of symbols

A. Hydrogen chloride absorption tower B. Reaction tower C.I. Hydrogen chloride recovery tower Distillation tower P.I. Pressurization equipment (absorption liquid pump)
1. Polyol supply line 2. Hydrogen chloride supply line 2A. Hydrogen chloride supply line 2B. To the hydrogen chloride absorption tower. Hydrogen chloride supply line to reaction tower 3. Hydrogen chloride absorbing solution extraction line 4. Catalyst supply line 5. Reaction tower supply line 6. Reaction liquid circulation line 7. Hydrogen chloride recovery tower supply line 8. Hydrogen chloride circulation line 9. Distillation Tower supply line 10. Chlorohydrin recovery line 11. Residue extraction line

Claims (9)

  A method for producing chlorohydrin, comprising reacting a hydrocarbon having 2 or more hydroxyl groups with 2 to 4 carbon atoms and hydrogen chloride in a liquid phase to replace the hydroxyl group of the hydrocarbon with chlorine, wherein the chloride is added in the liquid phase. A method for producing chlorohydrin in which hydrogen is dispersed as fine bubbles having an average diameter of 1000 μm or less.   The method for producing chlorohydrin according to claim 1, wherein the liquid phase is a saturated solution of hydrogen chloride.   The method for producing chlorohydrin according to claim 1 or 2, wherein the C2-C4 hydrocarbon having two or more hydroxyl groups is glycerin or monochloropropanediol.   The method for producing chlorohydrin according to claim 3, wherein the chlorohydrin is 1,3-dichloro-2-propanol.   The method for producing chlorohydrin according to any one of claims 1 to 4, wherein the reaction is performed in the presence of a catalyst.   The method for producing chlorohydrin according to any one of claims 1 to 5, wherein the hydrogen chloride is dispersed by introducing it into the liquid phase through fine pores.   Dissolving the hydrogen chloride in the liquid phase by dissolving it in a C2-C4 hydrocarbon having two or more hydroxyl groups under pressure, supplying it to a reaction vessel, and precipitating it in the reaction vessel The method for producing chlorohydrin according to any one of claims 1 to 6.   The method for producing chlorohydrin according to claim 1, wherein hydrogen chloride contained in the fine bubbles is 0.01 to 10 times the hydrogen chloride dissolved in the liquid phase.   The method for producing chlorohydrin according to claim 1, further comprising a step of recovering and reusing hydrogen chloride from the solution after the reaction.

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