JP2001002598A - Crystallization method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a target aromatic-substituted and chlorinated hydrocarbon compound of high purity in high yield by cooling a solution of a mixture of a plurality of aromatic-substituted and chlorinated hydrocarbons at a temperature reduction rate less than a specific value. SOLUTION: A solution of a mixture of the compounds represented by the formula: C6HkCl4-kR1R2 [R1 and R2 are each a group represented by the formula: C(CHmCl3-m) (CHnCl3-n) (Hp) (Cl1-p) (m and n are each 0-3; p is 0-1) for example, chlorination product of C6H4[CH(CH3)2]2) is cooled down at a cooling rate of <=1.0 deg.C/min, preferably 0.05-1.0 deg.C/min to crystallize out a compound of C6 HkCl4-kR3R4 [R3 and R4 are each a group represented by the formula: C(CHmCl3-m) (CHnCl3-n) [for example, 1,4-bis(1-chloro-methylethyl)benzene].

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to, for example, C ₆ H ₄ [C
From a mixture containing various aromatic substituted chlorinated hydrocarbons such as a chlorinated reaction product of H (CH ₃ ) ₂ ] ₂ , a target aromatic substituted chlorinated hydrocarbon is obtained in high yield and high purity. Related to the method of recovery.

[0002]

BACKGROUND OF THE INVENTION In general formula _{(3): C 6 H k} Cl 4-k R 3 R 4 (3) wherein, R ^3, R ⁴ are each formula _{(4): C (CH m} Cl 3- _m ) (CH _n Cl _3-n ) Cl (4) (wherein m and n are integers from 0 to 3), which may be the same or different. k is 0
4 is an integer. It has been known that the aromatic-substituted chlorinated hydrocarbon represented by the formula (1) can be used as a polymerization initiator when producing terminal-functional polyisobutylene.

[0003] Further, as a polymerization initiator for producing a terminal-functional polyisobutylene, C ₆ H ₄ [CCl (C
H _{3) 2] 2} are preferable, this C ₆ H ₄ [CH (C
It is also known that it can be synthesized by a chlorination reaction of H ₃ ) ₂ ] ₂ .

As a method for producing such a polymerization initiator, Fujisawa et al. Have proposed a method disclosed in JP-A-09-012616. However, when produced by this method, the purity of the target aromatic-substituted chlorinated hydrocarbon may be low. When a polymerization initiator having low purity is used, it becomes difficult to control the polymerization reaction, and as a result, there arises a problem that the molecular weight of the polymer is not uniform and the viscosity of the product is not stable.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for obtaining a desired aromatic-substituted chlorinated hydrocarbon compound from a mixture of various aromatic-substituted chlorinated hydrocarbon compounds in high purity and high yield. Is to provide.

[0006]

SUMMARY OF THE INVENTION The present invention has the general formula _{(1): C 6 H k} Cl 4-k R 1 R 2 (1) [wherein, R ^1, R ² are each the general formula (2) _{: C (CH m Cl 3-} m) (CH n Cl 3-n) (H p) (Cl 1-p) (2) ( wherein, m, n is an integer of from 0 to 3, p is 0-1 Is an integer.), And may be the same or different. k is an integer of 0-4. A solution of mixture of the compounds represented by], characterized by cooling so that the temperature drops at a rate of 1.0 ° C. / min or less, the general formula _{(3): C 6 H k} Cl 4-k R ³ R ⁴ (3) wherein R ³ and R ⁴ are each of the general formula (4): C (CH _m Cl _3-m ) (CH _n Cl _3-n ) Cl (4) , N is an integer of 0 to 3), and may be the same or different. k is 0
4 is an integer. A crystallization method for the compound represented by the formula:

[0007] The present invention also relates to C ₆ H ₄ [CH (CH ₃ ) ₂ ].
The mixed solution of the chlorination reaction product of No. ₂ was heated at a temperature of 1.0 ° C. /
The present invention relates to a method for crystallizing a compound represented by the above general formula (3), characterized in that the compound is cooled so as to decrease at a rate of not more than minutes.

Further, in the present invention, the compound represented by the general formula (1) or the chlorination reaction product of C ₆ H ₄ [CH (CH ₃ ) ₂ ] ₂ is converted into a hydrocarbon solvent and / or a halogen. After diluting with a chlorinated hydrocarbon solvent, it is preferable to isolate the crystals by performing cooling crystallization using a stirred crystallization tank.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The compound of the general formula (3) produced according to the present invention includes, for example, 1,4-bis (1-chloro-methylethyl) benzene [in the present specification, dicumyl chloride, p- DCC or DCC], 1- (1-chloro-methylethyl) -4- (1,
Examples thereof include 2-dichloro-methylethyl) benzene and 1,4-bis (1,2-dichloro-methylethyl) benzene, among which 1,4-bis (1-chloro-methylethyl) benzene is included. Is preferred.

The compound of the general formula (3) is a compound represented by C ₆ H
_It is preferably produced by a chlorination reaction of ₄ [CH (CH ₃ ) ₂ ] ₂ .

If the purity of the target product is low when p-DCC or the like is produced, the purity can be improved by a crystallization operation using an organic solvent. As the organic solvent used in the present invention, a halogenated hydrocarbon solvent or a hydrocarbon-based solvent having no halogen element can be used. Examples of the hydrocarbon-based solvent include pentane, n-hexane, cyclohexane, heptane, octane, methylcyclohexane, ethylcyclohexane, toluene, benzene, ethyl acetate, methyl isobutyl ketone, and mixtures thereof. Among them, as the solvent capable of obtaining the target compound as crystals in high yield, saturated hydrocarbons such as pentane, n-hexane, cyclohexane, heptane, octane, methylcyclohexane, ethylcyclohexane, and ethyl acetate are preferable.

Examples of the halogenated hydrocarbon include carbon tetrachloride, chloroform, methylene chloride, chloroethane, dichloroethane, propyl chloride, butyl chloride, monochlorobenzene, dichlorobenzene, ethyl chloride and the like, and mixtures thereof. .

The yield of the compound of the general formula (3) obtained by the crystallization method of the present invention is usually the same as that of the compound of the general formula (1) or the chlorination reaction of C ₆ H ₄ [CH (CH ₃ ) ₂ ] _2. It is at least 20% by weight, preferably at least 40% by weight, based on the amount of the product. The purity of the general formula (3) in the cake that can be recovered by filtering the crystal slurry of the general formula (3) obtained by the present invention is 75% by weight based on the weight of the cake.
However, it is preferably 85% by weight or more.

As the amount of the solvent, it is preferable to use the solvent described above in an amount of 0.5 to 20 times the weight of the aromatic-substituted chlorinated hydrocarbon represented by the general formula (3). A higher dilution ratio is better to obtain a high-purity target product,
If the dilution ratio is too large, the target substance also dissolves in the solvent, and the recovery rate decreases. Therefore, the dilution ratio is 0.1 in weight ratio.
More preferably, it is about 5 to 10 times.

[0015] In addition, since the purpose of such purification is to remove impurities, impurities in a mixture containing the target compound [ie, a compound represented by the general formula (1) and corresponding to the general formula (3)] Dilution ratio) can be set for the content of “No”. In this case, the dilution ratio is preferably about 1 to 20 times the weight of the impurities.

Although hydrocarbons and halogenated hydrocarbons can be used alone as solvents, however, various types of hydrocarbons and halogenated hydrocarbons are mixed to take advantage of the difference in the molecular structure of the target compound or impurity. By adjusting the polarity of the crystallization solvent, the purity and recovery of the target compound can be improved. Although the preferred mixing ratio varies depending on the target compound, for example, 1,4-bis (α-chloro-) is mixed in a mixed solvent of n-hexane and monochlorobenzene.
When isopropyl) benzene is crystallized, the weight ratio of n-hexane: monochlorobenzene is 0.95: 0.05.
To 0.6: 0.4.

The crystallization apparatus used in the present invention is not particularly limited. However, since many of the target compounds have an adhesive property, crystals are formed industrially and the crystals are efficiently recovered by filtration. An agitation-type crystallizer capable of performing the reaction is suitable. Regarding the shape of the apparatus, a vertically long crystallization tank having a ratio of tank diameter / tank height of 0.3 to 1.5 is preferable in order to increase the heat transfer area per liquid. As the stirring blade of the crystallization tank, the ratio of the blade diameter / tank diameter is 0.3 to 0.1 to avoid crushing the target crystal.
95 large wings, for example, Max Blend wings, full zone wings, Kaneka wings, H wings, anchor wings and the like can be used. Among them, in particular, the Max Blend blade, which is easy to control the crystal diameter and is expected to mix up and down the crystallization slurry,
It is preferable to use low-shear wings such as full zone wings and Kaneka wings. As the stirring speed in the tank, it is preferable to stir the required power per liquid amount at a relatively low speed within a range of 0.03 to 0.5 kW / m ³ .

In the present invention, it is preferable to crystallize and recover the target compound by a cooling operation using such a crystallization tank, but the cooling method may be any of self-evaporation, external circulation cooling, jacket cooling and the like. Is also effective. However, in the case of self-evaporation, the crystals become smaller, and in the case of external circulation cooling, crystals may adhere to the cooling surface. Therefore, jacket cooling is preferable.

Since the crystals are usually recovered by filtration,
In order to improve the filterability, the crystal size is preferably large, and the average particle size is preferably 100 μm or more. Under the conditions disclosed in the present invention, crystals having an average particle size of 100 to 400 μm are usually obtained.

In order to obtain a large crystal, it is necessary to reduce the number of crystal nuclei serving as crystal seeds and grow crystals around the crystal nuclei. Therefore, it is effective to keep the jacket temperature constant at the time of generation of crystal nuclei, thereby reducing the degree of supersaturation and reducing the number of generated crystal nuclei. The time to keep the temperature constant is usually 1-1.
00 minutes. Although the effect is exhibited even if the hold time is about 1 minute, it is preferable to set the hold time to 30 minutes or more in order to more effectively increase the crystal diameter.

In order to further grow the crystal, it is preferable to cool the crystallization liquid while keeping the degree of supersaturation low, and to suppress the generation of new crystal nuclei during cooling. When the cooling rate is 1.0 ° C./min or more, crystals tend to be generated rapidly, so that crystals having a small diameter tend to increase. for that reason,
It is preferable to cool so that the temperature decreases at a rate of 1.0 ° C./min or less.

The crystallization cooling end temperature (that is, the lowest temperature in the crystallization system) differs depending on the kind of the object and the solvent and the mixing ratio, but is a temperature at which impurities are hardly precipitated.
It is preferable to set the temperature in the range of −60 ° C.

After the crystallization is completed, the slurry is transferred to a filter and filtered. However, if the slurry is transferred immediately after the temperature at which the crystallization is completed, the slurry is not completely in a dissolution equilibrium state, so that the slurry is newly added in the filter. There is a concern that crystals will be generated, the number of fine particles will increase, and the filter will be blocked. Therefore, at the cooling end temperature (that is, the lowest temperature in the crystallization system), it is preferable to keep the jacket temperature constant for 1 to 180 minutes.

The recovery rate of the aromatic-substituted chlorinated hydrocarbon compound produced according to the method described in the present invention varies depending on the type of solvent, the mixing ratio thereof, the crystal concentration, and the cooling end temperature. It is 20 to 98% based on the charged amount. Industrially, a drop in recovery is a problem for profitability,
It is preferable to adjust the type of solvent, the mixture ratio thereof, the crystal concentration, and the cooling end temperature so as to obtain a recovery of 40% or more.

[0025]

According to the crystallization method of the present invention, an aromatic-substituted chlorinated hydrocarbon which is a cationic polymerization initiator can be obtained in high yield and high purity.

[0026]

The embodiments and effects of the present invention will be described below with reference to examples and comparative examples. However, the exemplification is for explanation, and the present invention is not limited by the examples. Preliminary Experiment 1 Using n-hexane (hydrocarbon) and chlorobenzene (halogenated hydrocarbon) as crystallization solvents, solvent composition and liquid temperature, and 1,4-bis (α-chloro-isopropyl) benzene (hereinafter referred to as p-DCC) ) Was investigated. The chlorination reaction solution of 1,4-diisopropylbenzene is analyzed by gas chromatography (hereinafter referred to as GC) to determine the weight percent of p-DCC and chlorobenzene (reactions other than p-DCC and chlorobenzene are determined). Consider by-products).

The chlorination reaction solution is mixed with a specified amount of n-hexane to form a crystallization solution. In this case, a representative value of the crystallization solvent composition is a hexane ratio, that is, n-hexane and a halogenated hydrocarbon (crystallized). Consider the weight ratio of chlorobenzene and the total amount of reaction by-products in the liquid.

50 g of the crystallized liquid is stirred in a 200 mL eggplant flask and cooled in an ethanol bath. After reaching each set temperature, a hold operation (holding the liquid temperature constant) is performed for 30 minutes. After the hold, the liquid is sampled while separating the crystals with a syringe equipped with a filter.

The solubility (% by weight) of p-DCC in the sampling solution was determined according to C. Was measured by Table 1 shows the results.

[0030]

[Table 1] Example 1 When the hexane ratio was 3, the solubility was measured when the weight ratio of p-DCC and the total amount of the solvent used (the total amount of n-hexane, chlorobenzene, and chlorination reaction by-products) was changed. The experimental method was the same as in Preliminary Experiment 1 except that pure p
-The concentration was adjusted by adding DCC, n-hexane, and chlorobenzene. The p-DCC weight% recovered as crystals from the p-DCC solubility was expressed as a percentage based on the charged p-DCC weight. The prepared pD shown in the results table
The CC concentration is a percentage by weight of p-DCC based on the total crystallization liquid. Table 2 shows the results.

[0031]

[Table 2] Comparative Example 1 Example 1 except that the charged concentration of p-DCC was 4% by weight.
The same operation as described above was performed. The p-DCC yield was 0% by weight. Example 2 The same operation as in Example 1 was performed except that the hexane ratio was 25.

The yield was estimated from the solubility of p-DCC. The yield was lower when the hexane ratio was 25 than when the hexane ratio was 3. Table 3 shows the results.

[0033]

[Table 3] Example 3 A crystallization liquid having a hexane ratio of 3 and a p-DCC concentration of 15% by weight was charged into a jacketed 1 L separable flask, the gas phase was replaced with nitrogen, and stirring was started. The stirring blade used was a Max Blend blade with (blade diameter) / (tank diameter) = 0.53, the stirring speed was 175 rpm, and the stirring power was 0.04 kW /
m is ^3. The tank has two baffles.

Ethanol, which can be cooled at a constant rate, is passed through the jacket by a temperature control device, and cooling is started at a predetermined rate from room temperature. When the crystallization liquid reaches −30 ° C., the liquid temperature is held for 30 minutes. Thereafter, the slurry is sampled, and the crystals are separated and collected by filtration. The obtained crystals are further subjected to solvent distillation and photographed under a microscope. The major axis of the crystal was measured from the photograph. In addition, G. C. The p-DCC purity of the crystals was measured by the method described above. Table 4 shows the results.

[0035]

[Table 4] Comparative Example 2 The same experiment as in Example 3 was performed at cooling rates of 3 ° C./min and 5 ° C./min. Table 5 shows the results.

[0036]

[Table 5] Example 4 Cooling was started under the same conditions as in Example 3, and after the crystallization was visually confirmed, the temperature of the crystallization liquid was kept constant by warming the jacket temperature until it became equivalent to the internal liquid. After holding for 1 hour, the jacket is cooled again at 0.3 ° C./min, and the crystallization liquid is cooled to −30 ° C.

The crystal diameter was measured in the same manner as in Example 3. Table 6 shows the results.

[0038]

[Table 6] Example 5 Under the same experimental conditions as in Example 3, the stirring speed and the stirring shaft torque at −30 ° C. were measured. The power required for stirring per unit volume of liquid was calculated from the stirring shaft torque. At the same time, the floating state of the crystals was visually observed at each stirring speed. Table 7 shows the results.

[0039]

[Table 7] Comparative Example 3 A similar experiment was performed at a lower stirring speed than in Example 5. Table 8 shows the results.

[0040]

[Table 8] Example 6 The same experiment as in Examples 3 and 5 was performed in a separable flask with a 5 L jacket having a similar shape to the crystallization tank used in Example 3. The weight of the crystallization liquid used was 3 kg,
The stirring speed during cooling to 30 ° C. is 125 rpm.
Table 9 shows the results.

[0041]

[Table 9] Comparative Example 4 A similar experiment was performed at a lower stirring speed than in Example 6. Table 10 shows the results.

[0042]

[Table 10] Example 7 Ethanol at -35 [deg.] C. was passed through a jacketed filter equipped with a filter area of 7 cm < ² > and filter paper or a filter cloth made of Teflon to precool. The slurry obtained under the same conditions as in Example 3 was discharged at a cooling rate of 0.3 ° C./min, and the pressure of the filter was increased to 0.02 MPa with nitrogen. The weight of the filtrate obtained 30 minutes after the start of pressurization was measured. The filtrate amount was 68% by weight based on the charged slurry, and the p-DCC purity of the cake was 75% by weight. Comparative Example 5 Example 3 except that the cooling rate during crystallization was 3 ° C./min.
Crystallization was carried out in the same manner as described above, followed by filtration in the same manner as in Example 7. The amount of the filtrate is 45% by weight based on the charged slurry,
The p-DCC purity of the cake was 62.5% by weight. Example 8 The slurry obtained under the same conditions as in Example 4 with a hold time of 1 hour was filtered in the same manner as in Example 7. The amount of the filtrate was 70% by weight based on the charged slurry, and the p-DCC purity of the cake was 76.5% by weight. Example 9 In the cake obtained in Example 8, hexane 22 at -30 ° C was added.
5 g was charged and the filter was pressurized to 0.02 MPa with nitrogen. After 30 minutes from the start of pressurization, the cake was distilled off, and the p-DCC content in the crystals was measured using G.C. C. Quantified by p-D
CC purity was 90% by weight. Comparative Example 6 The same operation as in Example 9 was performed on the cake obtained in Comparative Example 5. The p-DCC purity of the cake was 79.5% by weight. Example 10 The ratios of n-hexane and chlorobenzene in the crystallization solvent were changed, and the cooling rate was 0.3 ° C./min.
The experiment was performed in the same manner as in Example 9. Table 11 shows the results.

[0043]

[Table 11]

Claims (10)

[Claims] 1. A general formula _{(1): C 6 H k} Cl 4-k R 1 R 2 (1) [wherein, R ^1, R ² are each the general formula _{(2): C (CH m} Cl 3- Table in _{m) (CH n Cl 3-} n) (H p) (Cl 1-p) (2) ( wherein, m, n is an integer of 0 to 3, p is an integer of 0-1.) And may be the same or different. k is an integer of 0-4. A solution of mixture of the compounds represented by], characterized by cooling so that the temperature drops at a rate of 1.0 ° C. / min or less, the general formula _{(3): C 6 H k} Cl 4-k R ³ R ⁴ (3) wherein R ³ and R ⁴ are each of the general formula (4): C (CH _m Cl _3-m ) (CH _n Cl _3-n ) Cl (4) , N is an integer of 0 to 3), and may be the same or different. k is 0
4 is an integer. ] The crystallization method of the compound represented by these. 2. A mixed solution of a chlorination reaction product of C ₆ H ₄ [CH (CH ₃ ) ₂ ] ₂ is cooled so that the temperature decreases at a rate of 1.0 ° C./min or less. to the general formula _{(3): C 6 H k} Cl 4-k R 3 R 4 (3) wherein, R ^3, R ⁴ are each formula _{(4): C (CH m} Cl 3-m) (CH _n Cl _3-n ) Cl (4) (wherein m and n are integers from 0 to 3), which may be the same or different. k is 0
4 is an integer. ] The crystallization method of the compound represented by these. 3. A mixture of the compound represented by the general formula (1) is cooled by cooling the mixture at a rate of 0.05 to 1.0 ° C./min. At the time when the crystal of the compound represented by
The crystallization method according to claim 1, wherein the crystallization is held for 00 minutes. 4. After cooling the mixture of the compounds represented by the general formula (1), the mixture is cooled at the lowest temperature in the crystallization system.
The method according to claim 1, wherein the holding is performed for up to 180 minutes.
3. The crystallization method according to 3. 5. Cooling the mixture of chlorination reaction products of C ₆ H ₄ [CH (CH ₃ ) ₂ ] ₂ such that the temperature decreases at a rate of 0.05 to 1.0 ° C./min. By the time, when the crystal of the compound represented by the general formula (3) starts to be generated,
The crystallization method according to claim 2, wherein the liquid temperature is held for 1 to 100 minutes. 6. A method of cooling a mixture of chlorination reaction products of C ₆ H ₄ [CH (CH ₃ ) ₂ ] ₂ and holding the mixture at the lowest temperature in the crystallization system for 1 to 180 minutes. The crystallization method according to claim 2, wherein 7. A hydrocarbon-based solvent and / or a halogenated hydrocarbon-based solvent is used as a crystallization solvent, and the amount of the crystallization solvent used is based on the compound represented by the general formula (3). The crystallization method according to any one of claims 1, 2, 3, 4, 5, and 6, wherein the weight ratio is 0.5 to 20 times. 8. A compound represented by the general formula (1) wherein a hydrocarbon solvent and / or a halogenated hydrocarbon solvent is used as the crystallization solvent, and the amount of the crystallization solvent used is a compound represented by the general formula (1). 3. The composition according to claim 1, wherein the amount by weight is 1 to 20 times the amount of those not falling under the general formula (3).
3. The crystallization method according to 3, 4. 9. The ratio of blade diameter / tank diameter in the crystallization is from 0.3 to 0.3.
Using a stirring type crystallization tank equipped with a stirring blade of 0.95,
Power required for stirring per liquid amount is 0.03 to 0.5 kW / m
Crystallization method according to claim 5, 6, 7, 8, wherein the controlling the stirring speed such that the ^3. 10. A crystal having an average particle size of 100 to 400 μm obtained by the crystallization method according to claim 1.