阅读说明：本技术 1,3-环己二酮的结晶方法 (Crystallization method of 1, 3-cyclohexanedione ) 是由 曹璐 王磊 吴坤 倪肖元 李辛夷 汪韬 于 2019-11-28 设计创作，主要内容包括：本发明涉及结晶领域,公开了一种1,3-环己二酮的结晶方法,该方法包括：1)在40-48℃下,使1,3-环己二酮粗品溶解在有机溶剂中；2)在搅拌下,使溶解有1,3-环己二酮粗品的溶液降温至第一温度,并在所述第一温度下保温；3)在搅拌下,使保温后的溶液降温至第二温度,并在所述第二温度下保温,其中,相对于1g的1,3-环己二酮粗品,所述有机溶剂的用量为1-6ml,且所述有机溶剂选自甲苯、煤油、二氯乙烷和环己烷中的一种或多种；所述第一温度为20-30℃,降温至第一温度的降温速度为8-18℃/h；所述第二温度为3-10℃,降温至第二温度的降温速度为4-13℃/h。通过本发明的方法,其结晶收率高、晶体颗粒度大,并且简便易操作、成本低廉、废水量较少。(The invention relates to the field of crystallization, and discloses a crystallization method of 1, 3-cyclohexanedione, which comprises the following steps: 1) dissolving the 1, 3-cyclohexanedione crude product in an organic solvent at 40-48 ℃; 2) cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to a first temperature under stirring, and preserving heat at the first temperature; 3) cooling the heat-preserved solution to a second temperature under stirring, and preserving the heat at the second temperature, wherein the using amount of the organic solvent is 1-6ml relative to 1g of the 1, 3-cyclohexanedione crude product, and the organic solvent is selected from one or more of toluene, kerosene, dichloroethane and cyclohexane; the first temperature is 20-30 ℃, and the cooling speed for cooling to the first temperature is 8-18 ℃/h; the second temperature is 3-10 ℃, and the cooling speed for cooling to the second temperature is 4-13 ℃/h. The method has the advantages of high crystallization yield, large crystal granularity, simple and easy operation, low cost and less wastewater.)

1. A method for crystallizing 1, 3-cyclohexanedione, which comprises the steps of,

1) dissolving the 1, 3-cyclohexanedione crude product in an organic solvent at 40-48 ℃;

2) under the first stirring condition, cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to a first temperature, and preserving the heat at the first temperature for 0.5-2 hours;

3) under the second stirring condition, the temperature of the solution after heat preservation is reduced to a second temperature, and the solution is preserved for 0.5 to 3 hours at the second temperature,

wherein, in the step 1), the dosage of the organic solvent is 1-6ml relative to 1g of the crude product of the 1, 3-cyclohexanedione, and the organic solvent is selected from one or more of toluene, kerosene, dichloroethane and cyclohexane; in the step 2), the first temperature is 20-30 ℃, and the cooling speed for cooling to the first temperature is 8-18 ℃/h; in the step 3), the second temperature is 3-10 ℃, and the cooling speed for cooling to the second temperature is 4-13 ℃/h.

2. The method according to claim 1, wherein the organic solvent is used in an amount of 1 to 5ml per 1g of the crude 1, 3-cyclohexanedione in step 1).

3. The process according to claim 1, wherein in step 1), the crude 1, 3-cyclohexanedione is dissolved in toluene at 42-45 ℃.

4. The method according to any one of claims 1 to 3, wherein in step 2), the first temperature is 25 to 30 ℃ and the temperature is maintained at the first temperature for 0.8 to 1.5 hours.

5. A method according to any one of claims 1-3, wherein the first stirring speed in step 2) is 15-20 r/min.

6. The method according to any one of claims 1 to 3, wherein the cooling rate to the first temperature in step 2) is 10 to 15 ℃/h.

7. The method according to any one of claims 1 to 3, wherein in step 3), the second temperature is 4 to 8 ℃ and the temperature is maintained at the second temperature for 0.5 to 2 hours.

8. A method according to any one of claims 1-3, wherein in step 3) the second stirring speed is 10-20 r/min.

9. The method according to any one of claims 1 to 3, wherein the cooling rate to the second temperature in step 3) is 5 to 12.5 ℃/h.

10. The method according to any one of claims 1 to 3, wherein the 1, 3-cyclohexanedione content of the crude 1, 3-cyclohexanedione is from 90 to 92% by weight;

preferably, the method also comprises the step of carrying out solid-liquid separation on the crystallization liquid obtained in the step 3);

preferably, the method further comprises using a crystallization mother liquor obtained by solid-liquid separation as the organic solvent in step 1).

Technical Field

The invention relates to the field of crystallization, and particularly relates to a crystallization method of 1, 3-cyclohexanedione.

Background

The 1, 3-cyclohexanedione is used as a pharmaceutical intermediate for organic synthesis, and the 1, 3-cyclohexanedione is an important intermediate of herbicides sulcotrione and mesotrione. The 1, 3-cyclohexanedione is prepared by using resorcinol as a starting material, and performing hydrogenation reduction, acidification and recrystallization on the resorcinol to obtain a product, wherein the specific synthetic steps are shown as follows.

The prior 1, 3-cyclohexanedione product is usually crystallized by water, but the 1, 3-cyclohexanedione has better solubility in water, so that more products can be lost in a crystallization mother liquor, and high-salinity wastewater is increased along with the product, thereby bringing great pressure to wastewater treatment.

Disclosure of Invention

The invention aims to solve the problems of low crystallization yield and more high-salinity wastewater generation in the prior art, and provides a novel method for crystallizing 1, 3-cyclohexanedione, which has the advantages of high crystallization yield, large crystal granularity, simplicity, easiness in operation, low cost and less wastewater.

In order to achieve the above object, the present invention provides a method for crystallizing 1, 3-cyclohexanedione, which comprises the steps of,

1) dissolving the 1, 3-cyclohexanedione crude product in an organic solvent at 40-48 ℃;

2) under the first stirring condition, cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to a first temperature, and preserving the heat at the first temperature for 0.5-2 hours;

3) under the second stirring condition, the temperature of the solution after heat preservation is reduced to a second temperature, and the solution is preserved for 0.5 to 3 hours at the second temperature,

wherein, in the step 1), the dosage of the organic solvent is 1-6ml relative to 1g of the crude product of the 1, 3-cyclohexanedione, and the organic solvent is selected from one or more of toluene, kerosene, dichloroethane and cyclohexane; in the step 2), the first temperature is 20-30 ℃, and the cooling speed for cooling to the first temperature is 8-18 ℃/h; in the step 3), the second temperature is 3-10 ℃, and the cooling speed for cooling to the second temperature is 4-13 ℃/h.

Preferably, in the step 1), the amount of the organic solvent is 1 to 5ml relative to 1g of the crude 1, 3-cyclohexanedione.

Preferably, the crude 1, 3-cyclohexanedione is dissolved in toluene at from 42 to 45 ℃.

Preferably, in step 2), the first temperature is 25-30 ℃, and the temperature is kept at the first temperature for 0.8-1.5 hours.

Preferably, in the step 2), the speed of the first stirring is 15-20 r/min.

Preferably, in the step 2), the cooling rate of the temperature to the first temperature is 10-15 ℃/h.

Preferably, in the step 3), the second temperature is 4-8 ℃, and the temperature is kept at the second temperature for 0.5-2 hours.

Preferably, the second stirring speed is 10-20 r/min.

Preferably, in the step 3), the cooling rate of the second temperature is 5-12.5 ℃/h.

Preferably, the 1, 3-cyclohexanedione content of the crude 1, 3-cyclohexanedione product is from 90 to 92% by weight.

Preferably, the method further comprises the step of carrying out solid-liquid separation on the crystallization liquid obtained in the step 3).

Preferably, the method further comprises using a crystallization mother liquor obtained by solid-liquid separation as the organic solvent in step 1).

According to the crystallization method provided by the invention, the method has the advantages of high crystallization yield, large crystal granularity, simplicity, easiness in operation, low cost and less wastewater. And the mother liquor after crystallization can be produced indiscriminately, the discharge is further reduced, and the method is suitable for continuous production and is very suitable for industrial production.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

The invention provides a crystallization method of 1, 3-cyclohexanedione, which comprises the following steps,

1) dissolving the 1, 3-cyclohexanedione crude product in an organic solvent at 40-48 ℃;

2) under the first stirring condition, cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to a first temperature, and preserving the heat at the first temperature for 0.5-2 hours;

3) under the second stirring condition, the temperature of the solution after heat preservation is reduced to a second temperature, and the solution is preserved for 0.5 to 3 hours at the second temperature,

wherein, in the step 1), the dosage of the organic solvent is 1-6ml relative to 1g of the crude product of the 1, 3-cyclohexanedione, and the organic solvent is selected from one or more of toluene, kerosene, dichloroethane and cyclohexane; in the step 2), the first temperature is 20-30 ℃, and the cooling speed for cooling to the first temperature is 8-18 ℃/h; in the step 3), the second temperature is 3-10 ℃, and the cooling speed for cooling to the second temperature is 4-13 ℃/h.

According to the present invention, the content of 1, 3-cyclohexanedione in the crude 1, 3-cyclohexanedione product may be 90% by weight or more, preferably 90 to 95% by weight, more preferably 90 to 92% by weight.

Preferably, the crude 1, 3-cyclohexanedione product contains impurities of one or more of resorcinol, condensation impurities and sodium chloride.

The crude 1, 3-cyclohexanedione is particularly preferably a crude 1, 3-cyclohexanedione obtained by hydrogenating resorcinol as a starting material, acidifying, and removing the solvent.

According to the invention, the organic solvent is selected from one or more of toluene, kerosene, dichloroethane and cyclohexane. From the viewpoint of further improving the crystallization yield, crystal particle size and purity, it is preferable that the organic solvent is toluene.

According to the present invention, from the viewpoint of further improving the crystallization yield and purity, it is preferable that the amount of the organic solvent used in step 1) is 1 to 5ml relative to 1g of the crude 1, 3-cyclohexanedione.

According to the present invention, the crude 1, 3-cyclohexanedione is dissolved in an organic solvent, preferably at 42 to 45 ℃; more preferably, the crude 1, 3-cyclohexanedione is dissolved in toluene at 42-45 ℃.

According to the invention, preferably, in step 2), the first temperature is 25 to 30 ℃ and the temperature is maintained at the first temperature for 0.8 to 1.5 hours.

According to the invention, preferably, in step 2), the first stirring speed is 15-20 r/min. Through carrying out first stirring, it is big to have the granularity, wraps up the advantage that impurity is few.

According to the present invention, it is preferable that the cooling rate of the temperature to the first temperature in the step 2) is 10 to 15 deg.C/h from the viewpoint of further improving the crystallization yield, the crystal granularity and the purity.

According to the invention, preferably, in step 3), the second temperature is between 4 and 8 ℃ and the temperature is maintained at the second temperature for 0.5 to 2 hours.

According to the invention, the second stirring speed is preferably between 10 and 20 r/min. Through carrying out the second stirring, have that the granularity is big, the advantage that parcel impurity is few.

According to the present invention, it is preferable that the cooling rate of the temperature to the second temperature in the step 3) is 5 to 12.5 ℃/h from the viewpoint of further improving the crystallization yield, the crystal granularity and the purity.

According to the present invention, preferably, the method further comprises subjecting the crystallized liquid obtained in step 3) to solid-liquid separation. The method of the solid-liquid separation is not particularly limited, and for example, a method such as centrifugation or filtration can be used.

According to the present invention, preferably, the method further comprises using a crystallization mother liquor obtained by solid-liquid separation as the organic solvent in step 1) (i.e., recycling the crystallization mother liquor).

The number of applications of the crystallization mother liquor may be, for example, 20 to 30 times, preferably 15 to 30 times.

The present invention will be described in detail below by way of examples, but the present invention is not limited to the following examples.

In the following examples and comparative examples, the 1, 3-cyclohexanedione crude product was obtained by using resorcinol as a starting material, and subjecting the resorcinol to hydrogenation reduction, acidification and solvent removal, wherein the 1, 3-cyclohexanedione content in the 1, 3-cyclohexanedione crude product was 90 wt%.

Example 1

1) 50g of crude 1, 3-cyclohexanedione was dissolved in 250ml of toluene at 40 ℃ in a 500ml reaction flask;

2) under the stirring condition of 15r/min, cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to 30 ℃ at the cooling speed of 15 ℃/h, and preserving the heat for 1 hour at the temperature;

3) under the stirring condition of 10r/min, cooling the heat-preserved solution to 5 ℃ at the cooling speed of 12.5 ℃/h, and preserving the heat for 2 hours at the second temperature;

4) and 3) carrying out centrifugal separation on the crystallization liquid after heat preservation in the step 3) to obtain 1, 3-cyclohexanedione crystals with the purity of 98 weight percent and the yield of 96 percent, wherein the crystals are granular and have the particle size of DN 90-200 mu m.

Example 2

1) 50g of crude 1, 3-cyclohexanedione were dissolved in 55ml of toluene at 45 ℃ in a 500ml reaction flask;

2) under the stirring condition of 20r/min, cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to 25 ℃ at the cooling speed of 15 ℃/h, and preserving the heat for 1 hour at the temperature;

3) under the stirring condition of 20r/min, cooling the heat-preserved solution to 5 ℃ at the cooling speed of 5 ℃/h, and preserving the heat for 1 hour at the second temperature;

4) and 3) carrying out centrifugal separation on the crystallization liquid after heat preservation in the step 3) to obtain 1, 3-cyclohexanedione crystals with the purity of 99 wt% and the yield of 96%, wherein the crystals are granular and have the particle size of DN 90-200 mu m.

Example 3

1) 50g of crude 1, 3-cyclohexanedione was dissolved in 50ml of toluene at 42 ℃ in a 500ml reaction flask;

2) under the stirring condition of 20r/min, cooling the solution dissolved with the 1, 3-cyclohexanedione crude product to 25 ℃ at the cooling speed of 10 ℃/h, and preserving the heat for 1 hour at the temperature;

3) under the stirring condition of 20r/min, cooling the heat-preserved solution to 5 ℃ at the cooling speed of 5 ℃/h, and preserving the heat for 0.5 hour at the second temperature;

4) and 3) carrying out centrifugal separation on the crystallization liquid after heat preservation in the step 3) to obtain 1, 3-cyclohexanedione crystals with the purity of 99 wt% and the yield of 96%, wherein the crystals are granular and have the particle size of DN 90-200 mu m.

Example 4

The procedure was carried out as in example 1, except that kerosene was used as the solvent in step 1), and 1, 3-cyclohexanedione crystals were obtained in the same manner and had a purity of 98% by weight and a yield of 95%, the crystals were in the form of granules having a particle size of DN90 ═ 170 μm.

Example 5

The procedure was carried out as in example 1, except that dichloroethane was used as the solvent in step 1), and 1, 3-cyclohexanedione crystals were obtained in the same manner, with a purity of 98% by weight and a yield of 93%, in the form of granules having a particle size of DN90 ═ 180 μm.

Example 6

The procedure was carried out as in example 1, except that cyclohexane was used as the solvent in step 1), and 1, 3-cyclohexanedione crystals were obtained in the same manner and had a purity of 98% by weight and a yield of 95%, the crystals were in the form of granules having a particle size of DN90 ═ 180 μm.

Example 7

The procedure was carried out as in example 1, except that the solvent in step 1) was used in the mother liquor for crystallization obtained by centrifugation in example 1, and 1, 3-cyclohexanedione crystals were similarly obtained in a purity of 99% by weight in a yield of 96%, the crystals were in the form of granules having a particle size of DN90 ═ 200 μm.

In addition, the crystallization mother liquor obtained by centrifugal separation is repeatedly applied for 30 times, the purity of the obtained 1, 3-cyclohexanedione crystal is more than 98 weight percent, and the yield is more than 96 percent.

Comparative example 1

The procedure was carried out as in example 1, except that ethyl acetate was used as the solvent in step 1), and 1, 3-cyclohexanedione crystals were obtained in the same manner, with the purity of 98% by weight and the yield of 85%, in the form of granules having a particle size of DN90 ═ 180 μm.

Comparative example 2

The procedure was carried out as in example 1, except that chlorobenzene was used as the solvent in step 1), and 1, 3-cyclohexanedione crystals were obtained in the same manner with a purity of 97% by weight and a yield of 88% in the form of granules having a particle size of DN90 ═ 150 μm.

Comparative example 3

The procedure was followed as in example 1, except that the temperature decreasing rate in step 2) was 20 ℃/h, and 1, 3-cyclohexanedione crystals were obtained in the same manner, with a purity of 90% by weight and a yield of 93%, in the form of granules having a particle size of DN90 ═ 100 μm.

Comparative example 4

The procedure was followed as in example 1, except that the temperature decreasing rate in step 2) was 3 ℃/h, and 1, 3-cyclohexanedione crystals were obtained in the same manner, with a purity of 90% by weight and a yield of 92%, in the form of granules having a particle size of DN90 ═ 200 μm.

Comparative example 5

The procedure was followed as in example 1, except that the solvent in step 3) was water, and 1, 3-cyclohexanedione crystals were obtained in the same manner, with a purity of 98% by weight and a yield of 85%, in the form of granules having a particle size of DN90 ═ 100 μm.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.