JP5709656B2 - Process for producing polychloropropane - Google Patents

Description

  The present invention relates to a process for producing polychloropropane. More specifically, carbon tetrachloride and ethylene that is unsubstituted or substituted with chlorine are used as raw materials. Using an iron-phosphate ester catalyst, polychloropropane is produced, and after removing the phosphate ester, aluminum chloride is added as a catalyst. And it is related with the manufacturing method which 2-position of the obtained polychloropropane converts into further chlorinated polychloropropane by making it react with chlorine.

  Polychloropropane is important as a raw material or intermediate for producing various products such as agricultural chemicals, pharmaceuticals, and CFC substitute materials. For example, starting from 1,1,1,2,3-pentachloropropane and via 1,1,2,3-tetrachloropropene, trichloroallyldiisopropylthiocarbamate useful as a herbicide can be produced.

As a method for producing such a chlorinated hydrocarbon, for example, a first reaction in which carbon tetrachloride is added to an unsaturated compound having 2 carbon atoms (unsubstituted or chlorine-substituted ethylene) to obtain chloropropane,
A three-stage reaction is known which comprises a second reaction for dehydrochlorinating the chloropropane to obtain chloropropene and a third reaction for further adding chlorine to the chloropropene to obtain the desired chloropropane.

  Of these, the first reaction is, for example, in Patent Document 1, in which an addition reaction between ethylene and carbon tetrachloride is carried out in the presence of an iron-phosphoryl compound-based catalyst to obtain 1,1,1,3-tetrachloropropane. Is described. As the second and third reactions, for example, Patent Document 1 discloses 1,1,3-trichloro obtained by dehydrochlorinating 1,1,1,3-tetrachloropropane with an alkaline aqueous solution and then separating the aqueous solution. An example is described in which chlorine is used in a mixture of propene and 3,3,3-trichloropropene to make 1,1,1,2,3-pentachloropropane.

  Regarding the dehydrochlorination reaction of the second reaction, for example, Patent Document 2 describes a method of using iron chloride as a catalyst at a high temperature.

  Furthermore, as a method of performing the second and third reactions in one step, iron chloride is used as a catalyst, and 1,1,1,3-tetrachloropropane is blown into 1,1,1,3-tetrachloropropane under heating at a stroke. A method for obtaining 2,3-pentachloropropane has been proposed (Patent Document 3).

Japanese Examined Patent Publication No. 2-47969 JP-A 49-66613 US Patent Publication No. 2009/216055

  In the methods described in Patent Documents 1 and 2 described above, it is necessary to obtain extremely high-purity polychloropropane by removing various impurities in the raw material polychloropropane in order to prevent side reactions. In addition, since the two steps of the second and third reactions are performed under completely different conditions, a plurality of facilities are required, and time is required, which is uneconomical.

  The method described in Patent Document 3 does not have such a problem because the second and third reactions can be performed in one step, but on the other hand, it needs to be heated to a high temperature, and the selectivity of the target product is insufficient. There is much room for improvement.

  Therefore, the present invention does not require a high degree of purification of polychloropropane obtained by performing the first reaction using an iron-phosphate ester catalyst as the first step, and performs the second and third reactions in one step. In addition to obtaining the target product polychloropropane with sufficient conversion and selectivity, respectively, it is possible to reduce the total reaction time, simplify the equipment, and reduce the energy used.

  As a result of intensive studies in view of the above problems, the present inventors have removed the phosphate ester by simple purification after the first reaction, and employ aluminum chloride instead of iron chloride described in Patent Document 3. Reduces the time required for the purification of the intermediate chloropropane, simplifies the equipment, and performs the second and third reactions in a single step, allowing the reaction to proceed rapidly at a low temperature and significantly improving the selectivity. The present invention has been completed.

That is, the present invention
(A) Using an iron-phosphate ester catalyst, the following formula (1)
CCl _(2-m) H _m = CCl _(2-n) H _n (1)
Carbon tetrachloride is added to the unsaturated compound represented by the following formula (2)
_{CCl 3 -CCl (2-m)} H m -CCl (3-n) H n (2)
(In the above formulas, m is 1 or 2, and n is an integer of 0 to 2)
A first step of obtaining a crude chloropropane containing chloropropane represented by
(B) a second step of removing the phosphate ester from the crude chloropropane obtained in the first step, and
(C) The chloropropane from which the phosphate ester obtained in the second step has been removed and anhydrous aluminum chloride are placed in a reactor, and chlorine is introduced into the reactor, whereby the chloropropane is represented by the following formula ( 3)
_{CCl 3 -CCl (3-m)} H (m-1) -CCl (3-n) H n (3)
(In the above formula, m and n are the same integers as in formula (1)).
The third step of converting to chloropropane having one more chlorine number, as shown in
A process for producing polychloropropane, comprising the steps of:

  According to the present invention, only the phosphate ester is removed from the reaction mixture containing chloropropane represented by the formula (2) obtained by adding the unsaturated compound represented by the formula (1) to carbon tetrachloride. Therefore, the equipment for purification can be simplified and the energy used can be reduced. Further, when converting the chloropropane represented by the above formula (2) to the chloropropane represented by the above formula (3), there are conventionally two steps. It is possible to make the reaction step required to be one step, and at a relatively low temperature (that is, with low energy), to carry out the reaction in a high yield, which is extremely useful industrially.

Hereinafter, the present invention will be described in detail. In the present invention, the compound represented by the following formula (1) as a raw material is
Following formula (1)
CCl _(2-m) H _m = CCl _(2-n) H _n (1)
(In the above formula, m is 1 or 2, n is an integer of 0-2)
An unsaturated compound having a double bond having 2 carbon atoms and carbon tetrachloride.

  Specific examples of the unsaturated compound having a double bond having 2 carbon atoms related to the present invention are ethylene, vinyl chloride, 1,1-dichloroethylene, 1,2-dichloroethylene, and 1,1,2-trichloroethylene. . When carbon tetrachloride is added by an iron-phosphate ester catalyst described later, a product (chloropropane) represented by the following formula (2) in which carbon of carbon tetrachloride is bonded to carbon having a relatively small number of chlorine atoms. ) Occurs.

_{CCl 3 -CCl (2-m)} H m -CCl (3-n) H n (2)
(In the above formula, m and n are the same integers as in formula (1)).
For example, when ethylene is used as the raw material compound, 1,1,1,3-tetrachloropropane is obtained, and when vinyl chloride is used, 1,1,1,3,3-pentachloropropane is obtained.

  An example of the operation of the addition reaction in the first step will be described in more detail as follows. First, carbon tetrachloride is put in a reaction vessel under a temperature and pressure condition in which the carbon tetrachloride exists as a liquid phase, and an unsaturated compound having 2 carbon atoms is continuously supplied thereto as a gas. At this time, the total amount of iron used as a catalyst may be put in the reaction vessel from the beginning, while the total amount of phosphate ester may be put in the reaction vessel from the beginning, and the progress of the reaction may be monitored. However, it may be added gradually. The reaction state (rate) can be monitored by the consumption rate of the unsaturated compound having 2 carbon atoms.

Examples of the iron to be used include metallic iron, pure iron, soft iron, carbon steel, ferrosilicon steel, and alloys containing iron (for example, stainless steel). As the shape of iron, for example, it can be any shape such as powder, granule, lump, rod, sphere, plate, fiber, etc., and metal pieces that are further processed using these, distillation filling A thing etc. may be sufficient. Examples of the processed metal pieces include coils, nets, steel wool, and other irregular shaped pieces; examples of the distilled filler include Raschig rings and helices. Any of these forms can be used, but from the viewpoint of ensuring a sufficient contact area with the phosphate ester and the reactant, it is preferably in the form of powder or fiber. From the same viewpoint, the specific surface area of iron measured by the BET method using nitrogen as an adsorbate is preferably 0.001 to ⁵ m ² / g.

  The phosphoric acid esters include trimethyl phosphate, triethyl phosphate, tripropyl phosphate, tributyl phosphate, diethyl phosphate, dibutyl phosphate, monophenyl phosphate, monobutyl phosphate, dimethylphenyl phosphate, diethylphenyl phosphate. Dimethylethyl phosphate, phenylethylmethyl phosphate, and the like. Of these, phosphoric acid trialkyl esters are preferable, and phosphoric acid trialkyl esters in which all alkyl groups are alkyl groups having 1 to 4 carbon atoms are particularly preferable.

  The amount of phosphate ester used is preferably 0.001 mol or more, and 0.002 mol or more with respect to 1 mol of carbon tetrachloride used, from the viewpoint of ensuring high conversion and high selectivity. More preferably. The upper limit of the amount of phosphate ester used is not particularly limited, but if the amount used is excessively large, it becomes difficult to control the reaction due to heat generation, and the amount of phosphate ester that is wasted without being involved in the reaction increases. Economic disadvantage. From this point of view, the amount of phosphate ester used is preferably 1 mol or less, more preferably 0.1 mol or less, and 0.05 mol or less with respect to 1 mol of carbon tetrachloride. May be.

  The reaction temperature of the addition reaction depends on the type of unsaturated compound represented by the formula (1) and other reaction conditions, but is 90 to 160 ° C. in order to achieve both high conversion and high selectivity. The temperature is preferably 105 to 130 ° C.

  The reaction pressure may be a pressure at which the reaction system (a mixture of carbon tetrachloride and a reaction product) can maintain a liquid phase at the above reaction temperature, but in order to achieve both high conversion and high selectivity, It is preferable that the partial pressure of the unsaturated compound represented by the formula (1) is within a certain range. When the unsaturated compound represented by the formula (1) is ethylene, the ethylene partial pressure converted to 25 ° C. is preferably 0.11 to 0.52 MPa (abs), and preferably 0.15 to 0.35 MPa ( abs). When this is converted into reaction temperature, for example, at 110 ° C., it can be set to 0.15 to 0.65 MPa, and preferably 0.20 to 0.0.45 MPa (abs). If the ethylene partial pressure converted to 25 ° C. is less than 0.11 MPa, the concentration of the raw material compound (unsaturated compound) in the liquid phase may be too low and the reaction addition rate may be insufficient. When the pressure is exceeded, the rate at which multimers are produced increases and the selectivity may be impaired.

  In the present invention, in the first step as described above, the total amount of iron and a part of the phosphate ester are added before the start of the reaction, and the remaining phosphate ester is additionally added during the progress of the addition reaction. Is preferable in that the controllability of the resin is good, the conversion rate and the selectivity are increased, and the amount of iron and phosphate used can be reduced. Here, “before the reaction” refers to a time point before the temperature of the reactor is raised to a temperature at which carbon tetrachloride and the unsaturated compound substantially react. For example, when the unsaturated compound is ethylene, the temperature when the iron-phosphate ester catalyst is used is 90 ° C. Accordingly, the total amount of iron and all or part of the phosphate ester are preferably added when the reaction system is less than 90 ° C., and more preferably added at room temperature (when not heated).

  The addition of the phosphate ester may be performed only once, may be divided into several times, or may be performed continuously. The number of additional additions in the case of dividing into several times is preferably 2 to 10 times, and preferably 2 to 6 times. Here, there is an advantage that the operation is simple when the additional addition of the phosphate ester is performed only once, and there is an advantage that the reaction is easily controlled when this is performed continuously.

  The total amount of phosphate ester used (total amount in one batch of addition before starting reaction and additional addition) is preferably 0.001 mol or more with respect to 1 mol of carbon tetrachloride used, In particular, the amount is preferably 0.002 mol or more. The total amount of phosphate ester added in the case of additional addition is not particularly limited. However, if the total amount of phosphate ester added is excessively increased, it is economically disadvantageous in that the amount of phosphate ester that is wasted without being involved in the reaction increases. From this point of view, the total amount of phosphate ester added is preferably 1 mol or less, more preferably 0.1 mol or less, based on 1 mol of carbon tetrachloride. .01 mol or less may be used.

  In the method of adding phosphoric acid ester, even if the amount of the phosphoric acid ester is less than that of the conventional technique, for example, the method described in Patent Document 1 (Japanese Patent Publication No. 2-47969), the target compound Can be efficiently produced at a higher conversion and a stable reaction rate.

  In the method of the present invention, even when the total amount of the phosphate ester is added after the temperature of the reaction system is raised to a temperature at which the carbon tetrachloride and the unsaturated compound having 2 carbon atoms substantially react, the addition reaction proceeds. To do. However, in order to start up the reaction stably, at least a part thereof is preferably added before the temperature rise (before the start of the reaction). The addition amount of the phosphoric acid ester before the start of the reaction is preferably 0.0001 mol or more, more preferably 0.0005 mol or more with respect to 1 mol of carbon tetrachloride to be used. The upper limit of the phosphate ester added before the start of the reaction is independent of the mode of additional addition (whether the additional addition is performed once, divided into several times, or performed continuously), and In the case of additional addition divided into several times, regardless of the number of additions, it is preferably 80% or less, more preferably 70% or less of the total amount of phosphate ester used. By making the amount of phosphate ester added before the start of the reaction within the above range, the reaction can be stably started up, the reaction can be easily controlled, and as a result, a high conversion rate can be achieved. Become.

  The amount of iron used in the case where phosphoric acid esters are added all at once before the start of the reaction is 0 with respect to 1 mol of carbon tetrachloride used from the viewpoint of achieving both high reaction conversion and high selectivity. The amount is preferably 0.001 mol or more, more preferably 0.005 mol or more, and particularly preferably 0.01 mol or more. The upper limit of the amount of iron used is not particularly limited. Even if the amount of iron used is increased, the activity and selectivity are hardly affected, but the absolute amount of raw material that can be introduced into the reaction can is reduced by an amount equivalent to the volume of iron, and it is wasted without being involved in the reaction. It becomes economically disadvantageous in that the amount of iron becomes larger. From this viewpoint, the amount of iron used is preferably 10 mol or less, preferably 5 mol or less, more preferably 1 mol or less, particularly 1 mol of carbon tetrachloride to be used. The amount is preferably 0.1 mol or less.

  The amount of iron when the phosphate ester is added in portions can be made lower than the above value as the lower limit of the amount of iron used when the phosphate ester is added all at once before the start of the reaction. The amount of iron used in this case is preferably 0.0005 mol or more, more preferably 0.001 mol or more, particularly 0.005 mol or more, relative to 1 mol of carbon tetrachloride used. It is preferable that The upper limit of iron usage is set from an economic point of view. In this case, the amount of iron used is preferably 1 mol or less, more preferably 0.1 mol or less, and 0.05 mol or less with respect to 1 mol of carbon tetrachloride used. Is more preferable.

  The addition reaction thus started is preferably performed while continuously monitoring the consumption rate of the unsaturated compound having 2 carbon atoms. This continuous monitoring of the consumption rate of unsaturated compounds is performed, for example, by examining the amount of unsaturated compounds supplied to the gas phase in order to maintain an appropriate reaction pressure in a liquid phase batch reaction in the presence of the gas phase. be able to.

  When the phosphate ester is added only once, the consumption rate of the unsaturated compound is preferably 5 to 50%, more preferably 10 to 40% of the average consumption rate in 60 minutes after the start of the reaction. In addition, the entire remaining amount of phosphate ester is added. By this additional addition, the consumption rate of the unsaturated compound once reduced is recovered, and thereafter, the residual addition reaction proceeds while the consumption rate gradually decreases again.

  When the addition of the phosphate ester is performed in several divided portions, the consumption rate is preferably 5 to 50%, more preferably 10 to 40% of the average consumption rate in 60 minutes after the start of the reaction. The first addition of phosphate ester is performed. By the first additional addition, the consumption rate of the unsaturated compound once reduced is recovered, and thereafter, the consumption rate gradually decreases again. Then, when the consumption rate of the unsaturated compound is preferably 5 to 50%, more preferably 10 to 40% of the average consumption rate in 60 minutes after the start of the reaction, the second and subsequent additions of phosphate ester are added. Addition is performed. With this additional addition, the consumption rate of the unsaturated compound is restored again. Thereafter, the consumption rate of the unsaturated compound having 2 carbon atoms can be continuously monitored, and the phosphate ester can be additionally added a predetermined number of times.

  In the case where the addition of the phosphoric acid ester is divided into several times, it is preferable that the divided addition amount be set equal to the addition amount for each time or be gradually increased as the number of times is increased.

When the addition of the phosphate ester is continuously performed, it may be performed immediately after the start of the reaction, or the consumption rate is preferably 5 to 50% of the average consumption rate in 60 minutes after the start of the reaction, more preferably 10 to 10%. Additional addition of phosphate ester may be initiated when 40% is reached. This continuous addition of phosphoric acid makes it difficult to control the reaction when the addition rate is high, and it is economically disadvantageous because more phosphoric acid ester is wasted without being involved in the reaction. Further, when the addition rate is low, the reaction becomes slow. From this point of view, it is preferable to carry out at a rate of 1.3 × 10 ^{−6 to} 6.6 × 10 ⁻³ mol / min of phosphate ester relative to 1 mol of carbon tetrachloride, and 6.6 × 10 ⁻⁶ to More preferably, it is carried out at a rate of 6.6 × 10 ⁻⁴ molmol / min. This continuous addition is carried out by adding phosphoric acid to 1 mol of carbon tetrachloride when the consumption rate of unsaturated compounds having 2 carbon atoms is reduced to 5 to 50% of the average consumption rate in 60 minutes after the start of the reaction. Ester 1.3 × 10 ^{−6 to} 6.6 × 10 ⁻³ mol / min is preferably performed at a rate of 6.6 × 10 ^{−6 to} 6.6 × 10 ⁻⁴ mol mol / min. The addition rate may be increased from the middle. This continuous addition is preferably continued until the carbon tetrachloride conversion is 30 to 100%, more preferably 80 to 98%. The conversion rate of carbon tetrachloride can be judged from the consumption of unsaturated compounds.

  In the addition reaction performed as described above, the total reaction time is preferably 1 to 12 hours, and more preferably 2 to 10 hours.

  In this first step, it is better that the resulting reaction mixture (crude chloropropane) contains more chloropropane represented by the formula (2). Specifically, the reaction is preferably performed until 50% or more of carbon tetrachloride as a raw material has reacted, more preferably 80% or more, and still more preferably 90% or more. On the other hand, it is of course preferable that the upper limit is 100%, but it is difficult to make it substantially 100% because the reaction rate becomes very slow in the later stage of the reaction. Well, 98% or less is sufficient from an industrial point of view.

  The reaction mixture (crude chloropropane) obtained by the above method has chloropropane represented by the above formula (2) as a main component, carbon tetrachloride which is an unreacted raw material as impurities, and the carbon number represented by the above formula (1). 2 unsaturated compounds, chlorinated hydrocarbons represented by formulas other than formula (1) or (2) generated by side reactions, phosphate esters, iron, ferric chloride and the like.

  In the second step of the present invention, phosphate ester is removed from the impurities in the crude chloropropane. If the phosphate ester is removed from the impurities, it is a feature of the present invention that other impurities can be used as raw materials for the third step. The reason why the phosphate ester needs to be removed is that the phosphate ester acts as a catalyst that inhibits the dehydrochlorination reaction described later.

  As a method for removing the phosphate ester in the second step, for example, methods such as distillation, adsorption, column separation, and phosphate ester deactivation can be appropriately applied. When removing the phosphate ester, there is no problem even if other impurities are removed together.

  When distilling is used to remove the phosphate ester, the boiling point of the chloropropane represented by the formula (2) is compared with the boiling point of the phosphate ester used to determine whether the chloropropane is on the high boiling point side or the low boiling point side. And a collection operation may be performed.

  For example, when the chloropropane represented by the formula (2) is 1,1,1,3-tetrachloropropane, and the phosphate ester used from 1,1,1,3-tetrachloropropane has a high boiling point, The phosphate ester can be removed by simple distillation that collects substances having a boiling point lower than the boiling point. Examples of such a high boiling phosphate ester include trimethyl phosphate, triethyl phosphate, triisopropyl phosphate, tributyl phosphate, triphenyl phosphate, and the like. Normally, the chloropropane represented by the formula (2) obtained in the first step of the present invention has a lower boiling point than most phosphoric esters.

  In the present invention, since only the phosphate ester needs to be removed as described above, for example, when the chloropropane represented by the formula (2) is recovered as a low-boiling side substance in the above-described distillation, it is lower than the phosphate ester. Boiling substances (such as unreacted raw materials and chlorinated hydrocarbons as by-products) can be recovered together with the chloropropane and used for the next third step without any problem. In other words, it is not necessary to perform fractional distillation in order to recover high-purity chloropropane, and simple distillation that only recovers chloropropane represented by formula (2) and a substance having a boiling point lower than that by simple distillation or the like. It is the feature of this invention that it can move to the following 3rd process by performing. The method for removing the phosphate ester is not limited to distillation. For example, in the case of column separation, the phosphate ester and the chloropropane represented by the formula (2) are separated from each other before the chloropropane. Or it is possible to use for a 3rd process in the state containing the component which flows out later. Similarly, when removing the phosphate ester by adsorption, it can be subjected to the third step while containing impurities that are not adsorbed by the adsorbent.

  More specifically, the removal of the phosphate ester by distillation will be described by taking as an example the case where the raw material in the first step is ethylene and the phosphate ester is triethyl phosphate. The boiling point of 1,1,1,3-tetrachloropropane, which is chloropropane obtained when the raw material is ethylene, is lower than that of triethyl phosphate. Therefore, triethyl phosphate having a higher boiling point than 1,1,1,3-tetrachloropropane can be removed by performing simple distillation to collect substances having a lower boiling point than triethyl phosphate. At this time, high-boiling impurities such as iron and ferric chloride are also removed.

  On the other hand, substances having lower boiling points than triethyl phosphate include 1,1,1,3-tetrachloropropane, which is the target product, unreacted carbon tetrachloride, which is the main impurity, and chlorine, such as chloroform, which is a byproduct. Although all the hydrocarbons are included, none of the substances directly adversely affects the next reaction, so all can be recovered together. In the third step of the present invention, even if such low-boiling substances (carbon tetrachloride, by-products) are contained, high-purity 1,1,1,3 not containing the low-boiling substances. -It can be carried out with the same conversion and selectivity as when tetrachloropropane is used.

  In addition, even if a substance having a lower boiling point than that of chloropropane represented by the formula (2) such as 1,1,1,3-tetrachloropropane is fractionated by distillation, an apparatus and time for fractional distillation are not required except for that. There is no particular problem.

  As the distillation column used for the distillation, those known in the art can be used without limitation, and a plate column or a packed column can be mentioned as a preferable one. The purpose of this distillation is to remove phosphate esters. For example, triethyl phosphate and 1,1,1,3-tetrachloropropane have sufficient boiling points, so that triethyl phosphate can be removed with a small number of stages. There is no limit to the number of stages of the column tower or the equivalent number of stages of the distillation column converted into a column tower, but if it is too much, the cost of the distillation equipment increases, so 1 to 20 stages are preferable, and 1 to 5 stages. Is more preferable.

  The distillation tower may be performed in one tower or several towers. As the above-mentioned column tower, a cross flow tray, a shower tray, or the like can be used.

  As a packing in the case of using a packed distillation apparatus, a known packing such as a Raschig ring or a Lessing ring may be used, and the material is not limited, and various metals can be used.

  There are no particular restrictions on the conditions for carrying out the distillation, and the distillation can be carried out at normal pressure (101 kPa), and the temperature at the top of the distillation column can be performed even near the boiling point of chloropropane represented by the formula (2). If the temperature is too high (the temperature at the bottom of the column also becomes high), the chloropropane of formula (2) tends to decompose, and if the temperature at the top of the distillation column is too low, the energy for cooling the top of the distillation column increases during distillation. Moreover, since the pressure must be very low, the cost of the equipment and the operating cost are high. Therefore, the temperature range at the bottom of the column during distillation is preferably 20 ° C to 200 ° C, more preferably 50 ° C to 150 ° C, and more preferably 70 ° C to 120 ° C. Regarding the pressure at the time of distillation, the chloropropane of the formula (2) is vaporized at the above temperature, and the pressure can reach the upper part of the distillation column. Although the pressure varies depending on the type of chloropropane represented by the formula (2) and the temperature at the top of the distillation column, the pressure is preferably 1 kPa to 110 kPa. For example, when the chloropropane represented by the formula (2) is 1,1,1,3-tetrachloropropane, the distillation can be performed at a temperature of about 87 ° C. at the top of the distillation column at 10 kPa. There is almost no decomposition of 3-tetrachloropropane. The pressure here is an absolute pressure.

  In the case of distillation, it is not particularly necessary to add an additive, but a stabilizer may be added to suppress decomposition. Examples of the stabilizer include various phenols, for example, phenols substituted with an alkoxy group and phenols substituted with an allyl group. Specific examples of phenols substituted with an allyl group include o-allylphenol, m-allylphenol, p-allylphenol, 4-allyl-2-methoxyphenol (eugenol), 2-methoxy-4- (1 -Propenyl) phenol (isoeugenol) and the like. These allyl-substituted phenols may be used alone or in combination.

  When distillation is performed under such conditions, phosphates and substances having a boiling point higher than that of chloropropane represented by formula (2) are removed.

  Although there is no restriction | limiting in particular in the purity of the chloropropane represented by Formula (2) obtained by this distillation, 50-100% is preferable, 80-99% is more preferable, 90-98% is further more preferable.

  The amount of the phosphate ester contained in the chloropropane represented by the formula (2) obtained by this distillation is preferably 10000 ppmw or less, more preferably 1000 ppmw or less, and even more preferably 100 ppmw or less.

  When the removal of phosphate ester is adsorption, the method is, for example, to put silica gel in the reaction solution after the first step and stir to adsorb the phosphate ester to silica gel, and remove the silica gel to remove phosphate. Esters can also be removed.

  The method for measuring the purity of chloropropane represented by the formula (2) and the amount of phosphate ester is not particularly limited. For example, gas chromatography is used for separation, and a flame ionization detector (FID) is used as a detector. Each can be quantified. In addition to FID, a thermal conductivity detector, a mass analyzer, or the like can be used, and there is no particular limitation. As for phosphate esters, the phosphorus concentration can be quantified by an inductively coupled plasma optical emission spectrometer (ICP-OES).

  In the third step, the chloropropane represented by the formula (2) from which the phosphate ester has been removed reacted with chlorine through the chloropropene intermediate in the presence of aluminum chloride, and the number of chlorine at the 2-position increased by one (following formula (2) It is converted to chloropropane shown in 3).

_{CCl 3 -CCl (3-m)} H (m-1) -CCl (3-n) H n (3)
(In the above formula, m and n are the same integers as in formula (1)).
The estimated reaction mechanism of the third step of the present invention is as follows. That is, the chloropropane represented by the formula (2) is dehydrochlorinated using aluminum chloride as a catalyst to produce an intermediate chloropropene represented by the following formula (4).

_{CCl 2 = CCl (2-m} ) H m-1 -CCl (3-n) H n (4)
(In the above formula, m and n are the same integers as in formula (1)).
Thereafter, the reaction of adding the supplied chlorine to the double bond of the intermediate chloropropene is compared with the chloropropane corresponding to the formula (3), that is, the chloropropane represented by the formula (2). Thus, it is converted into chloropropane represented by the above formula (3) with one more chlorine at the 2-position.

  Specifically, as an example of chloropropane represented by the above formula (2), 1,1,1,3-tetrachloropropane will be described. First, 1,1,1,3-tetrachloropropane placed in a reaction vessel and By reaction of aluminum chloride, 1,1,3-trichloropropene is produced as a reaction intermediate resulting from dehydrochlorination. Subsequently, it is presumed that chlorine is added to the double bond of the 1,1,3-trichloropropene to produce 1,1,1,2,3-pentachloropropane.

  The reaction in the third step will be described in detail as follows. In the first embodiment, chloropropane and anhydrous aluminum chloride as described above are placed in a reaction vessel, and then chlorine is introduced into the reactor. When anhydrous aluminum chloride is not used, the target reaction does not proceed selectively. Further, by using aluminum chloride, the desired reactant can be obtained at a much lower temperature and with a higher selectivity than when other metal chlorides such as iron chloride are used.

  When there is no dissolved aluminum chloride in the reaction system, the dehydrochlorination reaction to chloropropene represented by formula (4) by dehydrochlorination of chloropropane represented by formula (2) Since the substitution reaction of chlorine with chloropropane represented by 2) proceeds, for example, when the chloropropane represented by formula (2) is 1,1,1,3-tetrachloropropane, 1,1,1,3, By-products such as 3-pentachloropropane are generated, and the selectivity of the desired 1,1,1,2,3-pentachloropropane tends to decrease.

  Therefore, it is desirable to supply chlorine after at least a part of anhydrous aluminum chloride is dissolved and the dehydrochlorination reaction is started, and it is important to appropriately adjust the amount of dissolution of anhydrous aluminum chloride. Whether or not anhydrous aluminum chloride is dissolved can be confirmed by a change in the color tone of the reaction solution. For example, when it is dissolved in 1,1,1,3-tetrachloropropane, it becomes blue when it is almost colorless.

  As aluminum chloride to be used, anhydrous aluminum chloride is used. Aluminum chloride hexahydrate does not substantially dissolve in chloropropane represented by the formula (2). In addition, aluminum hydroxide produced by the reaction of aluminum chloride with water does not serve as a catalyst for the dehydrochlorination reaction. However, even if aluminum hydroxide or aluminum chloride hexahydrate is contained in the system, the reaction is not particularly adversely affected.

  When the amount of anhydrous aluminum chloride dissolved in the reaction system is too large, the chloropropenes represented by the formula (4) produced by the dehydrochlorination reaction of chloropropane represented by the formula (2) or the formula (4 The dimerization by the reaction of the chloropropene represented by the formula (2) and the chloropropane represented by the formula (2) proceeds, so that the selectivity of the target chloropropane represented by the formula (3) tends to decrease.

Therefore, the amount of anhydrous aluminum chloride used is preferably 2.0 × 10 ^{−5 to} 2.0 × 10 ⁻² mol, and more preferably 5.10 mol to 1 mol of chloropropane represented by the formula (2). It is 0 * 10 < ^-5 > -1.0 * 10 < ^-3 > mol. In other words, when the total amount of anhydrous aluminum chloride is dissolved, it is preferably used so that the concentration is in the above range.

As described above, anhydrous aluminum chloride reacts (hydrolyzes) with water to become aluminum hydroxide. Accordingly, the amount of the anhydrous aluminum chloride is an amount substantially present in the reaction system. In other words, when water is contained in chloropropane as a raw material, the water and anhydrous aluminum chloride react to produce aluminum hydroxide, and the equivalent amount of water (water 3 per 1 mole of anhydrous aluminum chloride). It is sufficient to add a large amount of anhydrous aluminum chloride by the amount of (mol), so that the above amount is obtained. More specifically, the amount of anhydrous aluminum chloride actually used is 2.0 × 10 ^{−5 to} 2.0 × 10 ⁻² mol per 1 mol of chloropropane in addition to the equivalent amount of water contained in chloropropane. Is more preferable, and it is 5.0 * 10 < ^-5 > -1.0 * 10 < ^-3 > mol.

  Either chloropropane or anhydrous aluminum chloride may be fed into the reactor first. In addition to the batch reaction and the continuous reaction, a predetermined amount may be supplied at a time at first, or may be arbitrarily divided or continuously supplied during the reaction. Furthermore, anhydrous aluminum chloride may be dissolved in chloropropane outside the reactor, and this solution may be introduced into the reactor.

  A second embodiment is a method of preparing a solution of aluminum chloride outside the reactor and placing it in the reactor to prepare a solution in which aluminum chloride is dissolved in chloropropane represented by the formula (2). . As the aluminum chloride source to be used, anhydrous aluminum chloride can be used as in the case of preparing in the reactor described above. Further, the solvent in this case is not particularly limited as long as it does not inhibit the reaction of the present invention and can dissolve aluminum chloride, but it is a reaction substrate in consideration of purification operations such as impurity removal after the completion of the reaction. Chloropropane represented by the formula (2) is preferred.

  Other usable solvents include aluminum chloride, chlorine, carbon-carbon double bonds, etc., considering the yield and recovery of the target product (polychloropropane represented by formula (3)) after completion of the reaction. A solvent that does not easily react and has a boiling point different from that of the target product is preferable. Specific examples include various solvents such as chloromethane such as carbon tetrachloride and chloroform, and ethers such as tetrahydrofuran, dioxane and diethyl ether.

  As another method for preparing the aluminum chloride solution outside the reactor, metallic aluminum is added to the solvent, and chlorine and / or hydrogen chloride is introduced into the solvent to convert the metallic aluminum into aluminum chloride. It is a method to prepare. The solvent to be used is the same as the method using anhydrous aluminum chloride. In this method, insoluble impurities may be generated depending on the purity of the metal aluminum. It is preferable to introduce such an insoluble substance into the reactor after removing the prepared aluminum chloride solution by filtration or the like.

  In the above-described method for preparing an aluminum chloride solution outside the reactor, the concentration of aluminum chloride is adjusted to a high concentration, and the mixture is mixed with the chloropropane represented by the formula (2) in the reactor. In general, the concentration of aluminum chloride falls within the above range.

  A third embodiment is a method for preparing a chloropropane solution of aluminum chloride from metal aluminum in a reactor. In the chlorination in this case, it is preferable to use hydrogen chloride because chlorine tends to cause a side reaction. Specifically, chloropropane represented by the above formula (2) and metal aluminum are put in a reactor, and hydrogen chloride is introduced into the chloropropane. In this case, it is preferable to use a dried hydrogen chloride. The amount of metal aluminum used may be an amount in which the aluminum chloride concentration falls within the above range when the total amount of the metal aluminum is converted into aluminum chloride.

  Moreover, you may implement combining said 1st thru | or 3rd method suitably. The first aspect is most preferable from the viewpoints of apparatus cost, operation time, purity of the obtained aluminum chloride solution, and ease of concentration control.

  In the presence of aluminum chloride, the dehydrochlorination reaction of chloropropane represented by the above formula (2) occurs. This reaction is promoted at higher temperatures. Here, when chlorine is not supplied into the reaction system, there is a tendency to dimerize the dehydrochlorinated compounds with each other, or to proceed to a by-product by further reaction. Therefore, after mixing chloropropane and anhydrous aluminum chloride, the temperature of the reaction solution is preferably kept within the range of 50 ° C. or less, and more preferably 40 ° C. or less until the supply of chlorine is started. On the other hand, if the temperature is too low, dissolution of anhydrous aluminum chloride or metal aluminum is slow, and the concentration of aluminum chloride in the reaction system tends to be difficult to enter the above-mentioned range, so 0 ° C or higher is preferable, and more preferably 10 ° C or higher. is there.

  In the first aspect, the whole amount of chloropropane and anhydrous aluminum chloride represented by the formula (2) used in the reactor is introduced, and preferably after the dissolution of the aluminum chloride is confirmed, chlorine is introduced into the reactor. Supply. In the second embodiment, if the insoluble matter is removed by filtration or the like, it is not necessary to confirm dissolution in the reactor. In the third aspect, it is preferable to introduce chlorine after introducing hydrogen chloride until the total amount of metallic aluminum is dissolved. As the chlorine, general industrial chlorine can be used.

  If chlorine is introduced in a state where the concentration of chloropropane represented by the formula (2) is high and the concentration of chloropropene represented by the formula (3) is low, in addition to the dehydrochlorination reaction of the chloropropane. Thus, a chlorine substitution reaction occurs in a competitive reaction.

  For example, when the raw material of the third step is 1,1,1,3-tetrachloropropane, the concentration of 1,1,3-trichloropropene (product of dehydrochlorination) in the reaction system is low, and in addition dechlorination When the rate of hydrogen reaction is slow (for example, when the concentration of aluminum chloride is low) and the amount of chlorine supplied to the reaction system is large, the concentration of chlorine in the reaction system increases. As a result, 1,1,1,3,3-pentachloropropane is likely to be generated by the chlorine substitution reaction.

  On the other hand, when the concentration of the chloropropene represented by the above formula (3) in the reaction system becomes too high, as described above, the reaction between the chloropropenes and the reaction production represented by the chloropropene and the above formula (2). Side reactions such as reaction with chloropropane, which is a product, tend to occur.

  Therefore, the production method of the present invention can be carried out at a higher selectivity by setting the concentration of aluminum chloride in the reaction system within the above range, and setting the timing and supply rate of chlorine supply to an appropriate range. it can. Specifically, the supply of chlorine is determined by the concentration of the formula (4) chloropropene (1,1,3-trichloropropene when the raw material is 1,1,3-trichloropropene) by dehydrochlorination reaction. , Preferably 0.1 wt% to 30 wt%, more preferably 0.5 wt% to 20 wt%. The conversion rate of chloropropane can be easily determined from gas chromatographic analysis, the total amount of hydrogen chloride discharged to the gas phase, or the temperature change of the reaction solution when the heat removal amount is constant. The concentration in the reaction system can be easily grasped from the amount of chlorine.

  In consideration of the reaction efficiency, the final supply amount of chlorine is preferably 0.9 mol or more, more preferably 1 mol or more with respect to 1 mol of chloropropane represented by the formula (2). More preferably, 1.1 mol or more is supplied. On the other hand, even if too much, useless chlorine that does not contribute to the reaction increases, so the amount is preferably 2.5 mol or less, more preferably 2.0 mol or less with respect to 1 mol of chloropropane.

  The chlorine supply method may be initially supplied at a time (introduced into the reactor), but in this case, since side reactions are likely to occur as described above, it is preferable to supply gradually over a certain period of time. Although this supply time depends on the reaction temperature, the size of the reactor, etc., it is generally 0.5 to 20 hours, preferably about 1 to 10 hours. Moreover, when supplying over time, you may supply continuously and may supply intermittently.

  More preferably, the chlorine supply rate is such that the proportion of the chloropropene represented by the formula (4) in the reaction system is preferably 30 wt% or less, more preferably 20 wt% or less, and even more preferably 10 wt% or less. Adjust. Further, it is preferable to adjust the chlorine supply rate so that the chlorine concentration in the reaction system is preferably 10 wt% or less, more preferably 5 wt% or less, further preferably 3 wt% or less, and particularly preferably 1 wt% or less.

  The optimum chlorine supply amount for maintaining the concentration of chloropropene and chlorine represented by the above formula (4) in the reaction system varies depending on each temperature. However, when the reaction temperature is 0 to 50 ° C., the raw material initially charged The amount is preferably 1 to 2000 ml / min, more preferably 5 to 1000 ml / min, and still more preferably 10 to 500 ml / min with respect to 1 mol of chloropropane. Furthermore, in order to set the chlorine concentration in the reaction system within the above range, it is also preferable to change the flow rate in the above range during the reaction.

  For example, anhydrous aluminum chloride requires time until it is dissolved in chloropropane represented by the formula (2), so that the concentration of aluminum chloride is low at the beginning of the reaction and the dehydrochlorination reaction is delayed. Therefore, it is preferable that the chlorine supply amount is small in the initial stage and the supply amount is increased in the middle of the reaction. On the other hand, the proportion of the raw material chloropropane decreased in the latter stage of the reaction, but if the chlorine concentration is high in that state, the chlorine substitution of the chloropropane represented by the formula (3) further proceeds and the amount of impurities increases because the impurities increase. It is preferable to reduce it. From these things, after starting the chlorine supply, when the raw material chloropropane is preferably 95 wt% or less, more preferably 90 wt% or less, the chlorine supply amount is increased, and the intended reaction proceeds, and the raw material in the reaction system When the concentration of chloropropane is 30% wt or less, more preferably 20 wt% or less, a method of reducing the supply amount of chlorine can be suitably employed.

  When introducing chlorine into the reactor, it may be introduced into the gas phase portion in the reactor, or may be carried out by inserting the introduction tube into the reaction solution and blowing it into the solution.

  The form of the present invention may be performed by a batch reaction, or it is possible to continuously supply polychloropropane as a raw material to a reactor and continuously extract the produced polychloropropane. In this case, since anhydrous aluminum chloride is also taken out, it is preferable to additionally supply so that the amount of anhydrous aluminum chloride in the reaction system falls within the above range. For additional supply, a concentrated anhydrous chloropropane solution of anhydrous aluminum chloride [which may be either formula (2) or formula (3)] is prepared separately, and the chloropropane used as a raw material and solid anhydrous aluminum chloride are added. However, the latter method is preferable because it does not cause unnecessary impurities.

  For the same reason as described above, the temperature during supply of chlorine is also preferably maintained within a range of 0 to 50 ° C, more preferably 0 to 40 ° C, and further preferably 10 to 40 ° C. . Of the reactions that occur in the production method of the present invention, the chlorine addition reaction is an exothermic reaction, and the reaction as a whole is an exothermic reaction. System cooling is required. As the cooling (temperature adjustment of the reaction system), a method known in chemical engineering can be employed without any particular limitation.

  When the reaction is carried out batchwise, it is preferable to hold at the above temperature for about 0.1 to 2 hours after the introduction of the entire amount of chlorine into the reactor.

  After completion of the reaction, the target chloropropane represented by the formula (2) can be purified by a known method if necessary. However, the chloropropane represented by the formula (2), which is the target product, can further undergo a dehydrochlorination reaction at high temperatures in the presence of aluminum chloride. Therefore, when performing purification requiring high temperature (for example, distillation), it is preferable to remove the anhydrous aluminum chloride or to lose the activity of anhydrous aluminum chloride against dehydrochlorination. Examples of the method for removing anhydrous aluminum chloride include a method of adding a small amount of water, a method of bubbling with a wet gas (for example, an inert gas such as water vapor or nitrogen containing water vapor), a method of removing with an adsorbent, and the like. It is done. As a method of deactivating anhydrous aluminum chloride, the solution after the reaction may be allowed to stand or other components may be added so as not to function as a dehydrochlorination catalyst.

  When purifying by distillation, it is preferable to distill after adding a stabilizer in addition to the removal and deactivation of the anhydrous aluminum chloride. Examples of the stabilizer include various phenols, for example, phenols substituted with an alkoxy group and phenols substituted with an allyl group. Specific examples of phenols substituted with an allyl group include o-allylphenol, m-allylphenol, p-allylphenol, 4-allyl-2-methoxyphenol (eugenol), 2-methoxy-4- (1 -Propenyl) phenol (isoeugenol) and the like. These allyl-substituted phenols may be used alone or in combination.

  Unreacted chlorine can be recovered and used again as raw material chlorine for this reaction, or it can be refined and used as a raw material for other reactions.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

  In addition, as the reaction apparatus of the third step, the apparatus shown in the schematic diagram of FIG. 1 is used, and chlorine gas is blown into the reaction solution, and the gas that has been left unreacted and is generated. The experiment was conducted so that hydrogen chloride was discharged out of the reaction vessel.

Example 1
Filled with SUS autoclave (internal volume 1,500 mL) with stirrer, ethylene gas inlet and gas outlet, carbon tetrachloride and iron addition port, phosphate ester addition port and liquid discharge port It was. The autoclave was charged with 1,560 g of carbon tetrachloride, 2.0 g of triethyl phosphate and 4.0 g of K100 (Joke Steel Co., Ltd. coke reduced iron powder), the temperature was set to 110 ° C., and the total pressure in the gas phase The addition reaction was performed by supplying ethylene so that the pressure became 0.5 MPa (abs). The ethylene partial pressure in the gas phase immediately after the total pressure in the gas phase reached 0.5 MPa (abs) was 0.25 MPa.

  From the time when the temperature reached 110 ° C. and the total pressure in the gas phase reached 0.5 MPa (abs), triethyl phosphate was continuously added at 0.02 ml / min until the reaction was completed.

  During the reaction, ethylene is supplied so that the total pressure in the gas phase is maintained at 0.5 MPa (abs), and the ethylene consumption rate (additional supply rate) is 0.1% of the initial amount of carbon tetrachloride. The reaction was judged to be complete when the mol% / min (200 ml / min) was reached, and the addition reaction was terminated.

  The liquid after the reaction was extracted and analyzed by gas chromatography (hereinafter abbreviated as GC). The conversion of carbon tetrachloride was 97% and the selectivity to 1,1,1,3-tetrachloropropane was 96%.

  1000 g of the extracted reaction liquid was put into a 1 L flask, the liquid temperature was set to 90 ° C., the pressure was set to 10 kPa (abs), and batch distillation was performed. The gas coming to the top of the column was cooled, and 910 g of liquid was recovered by condensation. The recovered liquid contained about 97% of 1,1,1,3-tetrachloropropane, about 2% of carbon tetrachloride, and about 1% of other substances. Triethyl phosphate was not detected.

  Of the recovered liquid containing 97% of 1,1,1,3-tetrachloropropane, 182 g was placed in a 200 ml four-necked eggplant flask. Thereto was further added 0.10 g of anhydrous aluminum chloride. The liquid temperature was set to 20 ° C. and stirred for 1 hour. After confirming that the liquid turned blue and the aluminum chloride was dissolved, chlorine was allowed to flow in at 120 ml / min while maintaining the liquid temperature at 20 ° C. After 4 hours, the inflow of chlorine was stopped and nitrogen was circulated to expel chlorine. The reaction solution was analyzed by GC. The conversion of 1,1,1,3-tetrachloropropane was 100%, and the selectivity of 1,1,1,3-tetrachloropropane to 1,1,1,2,3-pentachloropropane was 94% (third Process yield 94%).

  The amount of carbon tetrachloride after the first step and that after the second step do not completely coincide with each other in calculation, but this is because the vapor pressure of carbon tetrachloride was high and could not be completely condensed and recovered. This difference is condensed and recovered in the exhaust trap.

Example 2
The first step was performed in the same manner as in Example 1 to obtain a reaction solution containing 95% of 1,1,1,3-tetrachloropropane. Place 1000 g of the reaction liquid into a 1 L flask, set the pressure to 10 kPa (abs), perform batch distillation, The purity of 1,1,1,3-tetrachloropropane was 99.9%. Triethyl phosphate was not detected in the 1,1,1,3-tetrachloropropane.

  182 g of 1,1,1,3-tetrachloropropane was placed in a 200 ml four-necked eggplant flask. Thereto was further added 0.10 g of anhydrous aluminum chloride. The liquid temperature was set to 20 ° C. and stirred for 1 hour. After confirming that the liquid turned blue and the aluminum chloride was dissolved, chlorine was allowed to flow in at 120 ml / min while maintaining the liquid temperature at 20 ° C. After 4 hours, the inflow of chlorine was stopped and nitrogen was circulated to expel chlorine. The reaction solution was analyzed by GC. The conversion of 1,1,1,3-tetrachloropropane was 100%, and the selectivity of 1,1,1,3-tetrachloropropane to 1,1,1,2,3-pentachloropropane was 93%.

Claims (2)

(A) Using an iron-phosphate ester catalyst, the following formula (1)
CCl _(2-m) H _m = CCl _(2-n) H _n (1)
Carbon tetrachloride is added to the unsaturated compound represented by the following formula (2)
_{CCl 3 -CCl (2-m)} H m -CCl (3-n) H n (2)
(In the above formulas, m is 1 or 2, and n is an integer of 0 to 2)
A first step of obtaining a crude chloropropane containing chloropropane represented by
(B) a second step of removing the phosphate ester from the crude chloropropane obtained in the first step, and
(C) The chloropropane from which the phosphate ester obtained in the second step has been removed and anhydrous aluminum chloride are placed in a reactor, and chlorine is introduced into the reactor, whereby the chloropropane is represented by the following formula ( 3)
_{CCl 3 -CCl (3-m)} H (m-1) -CCl (3-n) H n (3)
(In the above formula, m and n are the same integers as in formula (1)).
The third step of converting to chloropropane having one more chlorine number, as shown in
A process for producing polychloropropane, comprising the steps of:   The method for producing polychloropropane according to claim 1, wherein the removal of the phosphate ester in the second step is by distillation.