Production system and method for continuous chlorination of chloromethyl chloroformate

Abstract

The present invention relates to a production system and method for continuous chlorination of chloromethyl chloroformate, including a chlorination kettle, wherein the upper feed port of the chlorination kettle is communicated with an overhead tank through a vertical first pipeline and a horizontal second pipeline, a chlorine gas inlet pipe is provided at the bottom of the chlorination kettle, and the upper part of the vertical first pipeline is also communicated with the first condenser, the first gas-liquid separator, the second condenser and the second gas-liquid separator in sequence through a pipeline, and the liquid recovery port at the bottom of the first gas-liquid separator and the second gas-liquid separator is communicated with the chlorination kettle through a pipeline respectively and inserted below the liquid level, and the upper part of the chlorination kettle is communicated with the first evaporating kettle, the second evaporating kettle and a crude product collecting tank in sequence through a pipeline. The present invention, continuous feeding, continuous discharging, continuous chlorination, feeding control according to the exclusion of material liquid level, the yield of chloromethyl chloroformate is more than 90%, the crude product purity is more than 97%, and no rectification kettle is required on the equipment, reducing manpower transportation operation.

Description

Technical Field

[0001] The invention relates to the technical field of chemical equipment, and in particular to a production system and method for continuous chlorination of chloromethyl chloroformate. Background Art

[0002] Chloromethyl chloroformate, CAS No.: 22128-62-7, molecular formula: C 2 H 2 Cl 2 O 2 , molecular weight: 128.9421, is an organic chemical raw material. The traditional synthesis process is to put methyl chloroformate into a chlorination kettle, heat it to 65-70℃, introduce chlorine, react until the content of chloromethyl chloroformate reaches 30-35%, stop the chlorination reaction, transfer the material to a distillation kettle for distillation, recover methyl chloroformate, return the recovered methyl chloroformate to the chlorination kettle for re-chlorination, and continue to distill the remaining material after distilling and recovering methyl chloroformate to obtain the product chloromethyl chloroformate. It cannot be carried out continuously, the operation is complicated, the process is multi-step, the energy consumption is large, and the production capacity is low. The main problems are as follows: First, it is difficult to control the end point, resulting in a yield that is too low by about 35%. Second, a distillation kettle is required on the equipment, and the equipment requirements are high. Third, the purity of the crude product is only 35-40%, and there are many by-products of dichloro and trichloro products. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a production system and method for continuous chlorination of chloromethyl chloroformate.

[0004] The technical solution adopted by the present invention is:

[0005] A production system for continuous chlorination of chloromethyl chloroformate comprises a chlorination kettle, wherein an upper feeding port of the chlorination kettle is connected with an elevated tank through a vertical first pipeline and a horizontal second pipeline, a chlorine gas inlet pipe is arranged at the bottom of the chlorination kettle, the upper part of the vertical first pipeline is also connected with a first condenser, a first gas-liquid separator, a second condenser and a second gas-liquid separator in sequence through a pipeline, liquid recovery ports at the bottoms of the first gas-liquid separator and the second gas-liquid separator are respectively connected with the top of the chlorination kettle through pipelines and inserted below the liquid level, and the upper part of the chlorination kettle is connected with a first evaporation kettle, a second evaporation kettle and a crude product collection tank in sequence through a pipeline.

[0006] Preferably, the liquid level of the chlorination kettle is 5-10 cm higher than the liquid level of the first evaporation kettle, and the liquid level of the first evaporation kettle is 5-10 cm higher than the liquid level of the second evaporation kettle.

[0007] Preferably, a distributor is provided in the upper portion of the vertical first pipeline.

[0008] Preferably, the gas outlet of the second gas-liquid separator is connected to the falling film absorption tower through a pipeline, the falling film absorption tower is connected to the alkali liquid absorption tower, and the alkali liquid absorption tower is connected to the vacuum pump.

[0009] Preferably, the top exhaust ports of the first evaporation kettle and the second evaporation kettle are respectively connected to the top feed ports of the third condenser and the fourth condenser through pipelines, and the bottom discharge ports of the third condenser and the fourth condenser are respectively connected to the chlorination kettle through pipelines.

[0010] Preferably, the ratio of the diameter to the depth of the chlorination kettle is 1:3-4, to ensure that the chlorine gas and methyl chloroformate react completely, the chlorine gas is introduced from the bottom, the gas and liquid are in contact for a long time, and the reaction is complete.

[0011] The system is used to produce a continuous chlorination process for chloromethyl chloroformate, the process comprising the following steps:

[0012] 1) Chloromethyl chloroformate is put into the chlorination kettle through the header tank, the second pipeline and the first pipeline, the first condenser and the second condenser are turned on, the temperature of the chlorination kettle is increased, the ultraviolet lamp is turned on, and the temperature is maintained while chlorine gas and methyl chloroformate are continuously introduced for chlorination;

[0013] 2) The hydrogen chloride gas produced by the reaction in the chlorination kettle passes through the first condenser and the second condenser, and then passes through the first gas-liquid separator and the second gas-liquid separator to separate the night phase, and the liquid phase is recovered to the chlorination kettle for chlorination;

[0014] 3) The materials after the reaction in the chlorination kettle overflow into the first evaporation kettle, stir, evaporate the unreacted methyl chloroformate, condense the materials through the third condenser and then recover them to the chlorination kettle;

[0015] 4) The material from the first evaporator overflows and enters the second evaporator, where it is stirred and the undistilled methyl chloroformate is evaporated again. The material is condensed by the fourth condenser and then recycled to the chlorination kettle. The remaining material is collected in a crude product collection tank.

[0016] Completed the continuous chlorination production of chloromethyl chloroformate.

[0017] Preferably, in step 1), the temperature of the chlorination kettle is raised to 65-70°C.

[0018] Preferably, in step 1), the gas phase separated by the first gas-liquid separator and the second gas-liquid separator enters a falling film absorption tower for absorption to produce hydrochloric acid, and an alkali liquid absorption tower is used after the falling film absorption tower to absorb the unreacted chlorine gas, and then a vacuum pump is used for evacuation to form a slight negative pressure of 0 to 10 mmHg in the system.

[0019] Preferably, in steps 3) and 4), the temperature of the first evaporator and the second evaporator is controlled at 90-105°C.

[0020] Beneficial effects of the present invention:

[0021] 1. The present invention adopts the method of reacting, chlorinating, recovering raw materials and evaporating them, and recovering them into the chlorination kettle, continuously feeding, discharging and chlorinating. The feeding is controlled according to the liquid level of the discharged material. The liquid level of the chlorination kettle is 5-10cm higher than the liquid level of the first evaporation kettle, and the liquid level of the first evaporation kettle is 5-10cm higher than the liquid level of the second evaporation kettle. After the reaction reaches a certain degree, it is directly transferred to the evaporation kettle, eliminating the manual feeding operation and saving manpower.

[0022] 2. A distributor is provided in the upper part of the first vertical pipeline. After the raw materials enter, they are evenly distributed in the gas phase pipe. The materials are fully contacted with the evaporated materials so that the evaporated materials are returned to the chlorination kettle to heat the incoming raw materials. The unreacted chlorine continues to react with the raw materials to consume the chlorine.

[0023] 3. The ratio of the diameter to the depth of the chlorination kettle is 1:3-4. The diameter is small and the depth is large. Chlorine is introduced from the bottom. The contact time between chlorine and materials is long, the reaction is sufficient, and the overall reaction time is reduced.

[0024] 4. Due to the difference in boiling points between chloromethyl chloroformate and methyl chloroformate, methyl chloroformate is evaporated and removed, and chloromethyl chloroformate remains inside. The material temperature of the first evaporator is controlled at 100-105°C, and the methyl chloroformate is evaporated and cooled by the third condenser, and then enters the chlorination kettle. The unevaporated methyl chloroformate enters the second evaporator again for evaporation, and then enters the chlorination kettle after being cooled by the fourth condenser, so that the content of chloromethyl chloroformate is increased and meets the standard requirements for discharge.

[0025] 5. In the process of chlorine rising, the distributor on the upper part of the first pipeline of the distributor is used to preheat the material, which can save energy. In the past, intermittent operation required about 0.5 tons of steam to produce one ton of chloromethyl chloroformate. After adopting this system, more than 40% of energy can be saved.

[0026] 6. The yield of chloromethyl chloroformate of the present invention is more than 90%, no rectification kettle is needed on the equipment, the equipment requirement is not high, the manpower transportation operation is reduced, and the crude product purity is more than 97%. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 : Schematic diagram of the structure of the present invention;

[0028] In the figure: chlorination kettle 1, first pipeline 2, second pipeline 3, high-level tank 4, chlorine gas inlet pipe 5, distributor 6, first condenser 7, first gas-liquid separator 8, second condenser 9, second gas-liquid separator 10, first evaporation kettle 11, second evaporation kettle 12, crude product collecting tank 13, third condenser 14, fourth condenser 15. DETAILED DESCRIPTION

[0029] Example 1

[0030] like Figure 1 As shown, a production system for continuous chlorination of chloromethyl chloroformate comprises a chlorination kettle 1, wherein an upper feed port of the chlorination kettle 1 is connected to an elevated tank 4 through a vertical first pipeline 2 and a horizontal second pipeline 3, a chlorine gas inlet pipe 5 is provided at the bottom of the chlorination kettle 1, and an upper portion of the vertical first pipeline 2 is also connected to a first condenser 7, a first gas-liquid separator 8, a second condenser 9 and a second gas-liquid separator 10 in sequence through a pipeline, liquid recovery ports at the bottoms of the first gas-liquid separator 8 and the second gas-liquid separator 10 are respectively connected to the top of the chlorination kettle 1 through pipelines and inserted below the liquid level, and an upper portion of the chlorination kettle 1 is connected to a first evaporation kettle 11, a second evaporation kettle 12 and a crude product collection tank 13 in sequence through a pipeline.

[0031] Preferably, the liquid level of the chlorination kettle 1 is 5-10 cm higher than the liquid level of the first evaporation kettle 11 , and the liquid level of the first evaporation kettle 11 is 5-10 cm higher than the liquid level of the second evaporation kettle 12 .

[0032] Preferably, a distributor 6 is provided in the upper portion of the vertical first pipeline 2 .

[0033] Preferably, the gas outlet of the second gas-liquid separator 10 is connected to the falling film absorption tower through a pipeline, the falling film absorption tower is connected to the alkali liquid absorption tower, and then connected to the vacuum pump.

[0034] Preferably, the top exhaust ports of the first evaporation kettle 11 and the second evaporation kettle 12 are respectively connected to the top feed ports of the third condenser 14 and the fourth condenser 15 through pipelines, and the bottom discharge ports of the third condenser 14 and the fourth condenser 15 are respectively connected to the chlorination kettle 1 through pipelines.

[0035] Preferably, the ratio of the diameter to the depth of the chlorination kettle 1 is 1:3-4.

[0036] Example 2

[0037] The production process of continuous chlorination of chloromethyl chloroformate carried out by the system of Example 1,

[0038] The liquid level of the chlorination kettle 1 is 10 cm higher than the liquid level of the first evaporation kettle 11 , and the liquid level of the first evaporation kettle 11 is 10 cm higher than the liquid level of the second evaporation kettle 12 .

[0039] The process comprises the following steps:

[0040] 1) Chloromethyl chloroformate is put into the chlorination kettle 1 through the header tank 4, the second pipeline 3 and the first pipeline 2, the first condenser 7 and the second condenser 9 are turned on, the chlorination kettle 1 is heated, the ultraviolet lamp is turned on, and the temperature is maintained while chlorine gas and methyl chloroformate are continuously introduced for chlorination;

[0041] 2) The hydrogen chloride gas produced by the reaction in the chlorination kettle 1 passes through the first condenser 7 and the second condenser 9, and then passes through the first gas-liquid separator 8 and the second gas-liquid separator 10 to separate the night phase, and the liquid phase is recovered to the chlorination kettle 1 for chlorination;

[0042] 3) The materials after the reaction in the chlorination kettle 1 overflow into the first evaporation kettle 11, where they are stirred to evaporate the unreacted methyl chloroformate, and the materials are condensed by the third condenser 14 and then recycled to the chlorination kettle 1;

[0043] 4) The material in the first evaporation kettle 11 overflows and enters the second evaporation kettle 12, where it is stirred and the undistilled methyl chloroformate is evaporated again. The material is condensed by the fourth condenser 15 and then recycled to enter the chlorination kettle 1. The remaining material is collected in the crude product collection tank 13;

[0044] Completed the continuous chlorination production of chloromethyl chloroformate.

[0045] Preferably, in step 1), the temperature of the chlorination kettle 1 is raised to above 65°C.

[0046] Preferably, in step 1), the gas phase separated by the first gas-liquid separator 8 and the second gas-liquid separator 10 enters a falling film absorption tower for absorption to produce hydrochloric acid, and an alkali liquid absorption tower is used after the falling film absorption tower to absorb the unreacted chlorine gas, and then a vacuum pump is used for evacuation to form a slight negative pressure of 5 mmHg in the system.

[0047] Preferably, in steps 3) and 4), the temperature of the first evaporation pot 11 and the second evaporation pot 12 is controlled at 95°C.

[0048] The yield of chloromethyl chloroformate in this embodiment is 92%, and the crude product purity is 97%.

[0049] Example 3

[0050] The production process of continuous chlorination of chloromethyl chloroformate carried out by the system of Example 1,

[0051] The liquid level of the chlorination kettle 1 is 5 cm higher than the liquid level of the first evaporation kettle 11 , and the liquid level of the first evaporation kettle 11 is 10 cm higher than the liquid level of the second evaporation kettle 12 .

[0052] The process comprises the following steps:

[0053] 1) Chloromethyl chloroformate is put into the chlorination kettle 1 through the header tank 4, the second pipeline 3 and the first pipeline 2, the first condenser 7 and the second condenser 9 are turned on, the chlorination kettle 1 is heated, the ultraviolet lamp is turned on, and the temperature is maintained while chlorine gas and methyl chloroformate are continuously introduced for chlorination;

[0054] 2) The hydrogen chloride gas produced by the reaction in the chlorination kettle 1 passes through the first condenser 7 and the second condenser 9, and then passes through the first gas-liquid separator 8 and the second gas-liquid separator 10 to separate the night phase, and the liquid phase is recovered to the chlorination kettle 1 for chlorination;

[0055] 3) The materials after the reaction in the chlorination kettle 1 overflow into the first evaporation kettle 11, where they are stirred to evaporate the unreacted methyl chloroformate, and the materials are condensed by the third condenser 14 and then recycled to the chlorination kettle 1;

[0056] 4) The material in the first evaporation kettle 11 overflows and enters the second evaporation kettle 12, where it is stirred and the undistilled methyl chloroformate is evaporated again. The material is condensed by the fourth condenser 15 and then recycled to enter the chlorination kettle 1. The remaining material is collected in the crude product collection tank 13;

[0057] Completed the continuous chlorination production of chloromethyl chloroformate.

[0058] Preferably, in step 1), the temperature of the chlorination kettle 1 is raised to 70°C.

[0059] Preferably, in the step 1), the gas phase separated by the first gas-liquid separator 8 and the second gas-liquid separator 10 enters a falling film absorption tower for absorption to produce hydrochloric acid, and an alkali liquid absorption tower is used after the falling film absorption tower to completely absorb the unreacted chlorine gas, and then a vacuum pump is used for evacuation to form a slight negative pressure of 10 mmHg in the system.

[0060] Preferably, in steps 3) and 4), the temperature of the first evaporation pot 11 and the second evaporation pot 12 is controlled at 105°C.

[0061] The yield of chloromethyl chloroformate in this embodiment is 94%, and the crude product purity is 98%.

[0062] Example 4

[0063] The production process of continuous chlorination of chloromethyl chloroformate carried out by the system of Example 1,

[0064] The liquid level of the chlorination kettle 1 is 8 cm higher than the liquid level of the first evaporation kettle 11 , and the liquid level of the first evaporation kettle 11 is 8 cm higher than the liquid level of the second evaporation kettle 12 .

[0065] The process comprises the following steps:

[0066] 1) Chloromethyl chloroformate is put into the chlorination kettle 1 through the header tank 4, the second pipeline 3 and the first pipeline 2, the first condenser 7 and the second condenser 9 are turned on, the chlorination kettle 1 is heated, the ultraviolet lamp is turned on, and the temperature is maintained while chlorine gas and methyl chloroformate are continuously introduced for chlorination;

[0067] 2) The hydrogen chloride gas produced by the reaction in the chlorination kettle 1 passes through the first condenser 7 and the second condenser 9, and then passes through the first gas-liquid separator 8 and the second gas-liquid separator 10 to separate the night phase, and the liquid phase is recovered to the chlorination kettle 1 for chlorination;

[0068] 3) The materials after the reaction in the chlorination kettle 1 overflow into the first evaporation kettle 11, where they are stirred to evaporate the unreacted methyl chloroformate, and the materials are condensed by the third condenser 14 and then recycled to the chlorination kettle 1;

[0069] 4) The material in the first evaporation kettle 11 overflows and enters the second evaporation kettle 12, where it is stirred and the undistilled methyl chloroformate is evaporated again. The material is condensed by the fourth condenser 15 and then recycled to enter the chlorination kettle 1. The remaining material is collected in the crude product collection tank 13;

[0070] Completed the continuous chlorination production of chloromethyl chloroformate.

[0071] Preferably, in step 1), the temperature of the chlorination kettle 1 is raised to 68°C.

[0072] Preferably, in step 1), the gas phase separated by the first gas-liquid separator 8 and the second gas-liquid separator 10 enters a falling film absorption tower for absorption to produce hydrochloric acid, and a vacuum pump is used to evacuate gas after the falling film absorption tower to form a slight negative pressure of 8 mmHg in the system.

[0073] Preferably, in steps 3) and 4), the temperature of the first evaporation kettle 11 and the second evaporation kettle 12 is controlled at 100°C.

[0074] The yield of chloromethyl chloroformate in this embodiment is 96%, and the crude product purity is 97%.

[0075] Example 5

[0076] The production process of continuous chlorination of chloromethyl chloroformate carried out by the system of Example 1,

[0077] The liquid level of the chlorination kettle 1 is 8 cm higher than the liquid level of the first evaporation kettle 11 , and the liquid level of the first evaporation kettle 11 is 7 cm higher than the liquid level of the second evaporation kettle 12 .

[0078] The process comprises the following steps:

[0079] 1) Chloromethyl chloroformate is put into the chlorination kettle 1 through the header tank 4, the second pipeline 3 and the first pipeline 2, the first condenser 7 and the second condenser 9 are turned on, the chlorination kettle 1 is heated, the ultraviolet lamp is turned on, and the temperature is maintained while chlorine gas and methyl chloroformate are continuously introduced for chlorination;

[0080] 2) The hydrogen chloride gas produced by the reaction in the chlorination kettle 1 passes through the first condenser 7 and the second condenser 9, and then passes through the first gas-liquid separator 8 and the second gas-liquid separator 10 to separate the night phase, and the liquid phase is recovered to the chlorination kettle 1 for chlorination;

[0081] 3) The materials after the reaction in the chlorination kettle 1 overflow into the first evaporation kettle 11, where they are stirred to evaporate the unreacted methyl chloroformate, and the materials are condensed by the third condenser 14 and then recycled to the chlorination kettle 1;

[0082] 4) The material in the first evaporation kettle 11 overflows and enters the second evaporation kettle 12, where it is stirred and the unevaporated methyl chloroformate is evaporated again. The material is condensed by the fourth condenser 15 and then recycled to enter the chlorination kettle 1. The remaining material is collected in the crude product collection tank 13;

[0083] Completed the continuous chlorination production of chloromethyl chloroformate.

[0084] Preferably, in step 1), the temperature of the chlorination kettle 1 is raised to 68°C.

[0085] Preferably, in step 1), the gas phase separated by the first gas-liquid separator 8 and the second gas-liquid separator 10 enters a falling film absorption tower for absorption to produce hydrochloric acid, and a vacuum pump is used to evacuate gas after the falling film absorption tower to form a slight negative pressure of 4 mmHg in the system.

[0086] Preferably, in steps 3) and 4), the temperature of the first evaporation pot 11 and the second evaporation pot 12 is controlled at 102°C.

[0087] The yield of chloromethyl chloroformate in this embodiment is 96%, and the crude product purity is 99%.

Claims

1. A production system for continuous chlorination of chloromethyl chloroformate, comprising a chlorination kettle (1), characterized in that: The upper feed port of the chlorination kettle (1) is connected to the high-level tank (4) through a vertical first pipeline (2) and a horizontal second pipeline (3). A chlorine gas inlet pipe (5) is provided at the bottom of the chlorination kettle (1). The upper part of the vertical first pipeline (2) is also connected to the first condenser (7), the first gas-liquid separator (8), the second condenser (9) and the second gas-liquid separator (10) in sequence through pipelines. The liquid recovery ports at the bottom of the first gas-liquid separator (8) and the second gas-liquid separator (10) are respectively connected to the top of the chlorination kettle (1) through pipelines and inserted into the liquid surface to The upper part of the chlorination kettle (1) is connected to the first evaporation kettle (11), the second evaporation kettle (12) and the crude product collection tank (13) in sequence through a pipeline; the liquid level of the chlorination kettle (1) is 5-10 cm higher than the liquid level of the first evaporation kettle (11), and the liquid level of the first evaporation kettle (11) is 5-10 cm higher than the liquid level of the second evaporation kettle (12); a distributor (6) is provided in the upper part of the vertical first pipeline (2); the gas outlet of the second gas-liquid separator (10) is connected to the falling film absorption tower through a pipeline, and the falling film absorption tower is connected to the vacuum pump; The top exhaust ports of the first evaporation kettle (11) and the second evaporation kettle (12) are respectively connected to the top feed ports of the third condenser (14) and the fourth condenser (15) through pipelines, and the bottom discharge ports of the third condenser (14) and the fourth condenser (15) are respectively connected to the chlorination kettle (1) through pipelines; The ratio of the diameter to the depth of the chlorination kettle (1) is 1:3-4.

2. The production process of continuous chlorination of chloromethyl chloroformate carried out by the production system according to claim 1, characterized in that: The process comprises the following steps: 1) methyl chloroformate is introduced into a chlorination kettle (1) through an overhead tank (4) via a second pipeline (3) and a first pipeline (2), a first condenser (7) and a second condenser (9) are turned on, the temperature of the chlorination kettle (1) is increased, an ultraviolet lamp is turned on, and chlorine gas and methyl chloroformate are continuously introduced to maintain the temperature for chlorination; 2) The hydrogen chloride gas generated by the reaction in the chlorination kettle (1) passes through the first condenser (7) and the second condenser (9), and then passes through the first gas-liquid separator (8) and the second gas-liquid separator (10) to separate the gas and liquid phases, and the liquid phase is recovered to the chlorination kettle (1) for chlorination; 3) the materials after the reaction in the chlorination kettle (1) overflow into the first evaporation kettle (11), where they are stirred to evaporate the unreacted methyl chloroformate, and the materials are condensed by the third condenser (14) and then recycled to the chlorination kettle (1); 4) The material in the first evaporator (11) overflows and enters the second evaporator (12), where it is stirred to evaporate the undistilled methyl chloroformate again. The material is condensed by the fourth condenser (15) and then recovered to the chlorination kettle (1). The remaining material is collected in a crude product collection tank (13); Completed the continuous chlorination production of chloromethyl chloroformate.

3. The production process according to claim 2, characterized in that: In the step 1), the temperature of the chlorination kettle (1) is raised to 65-70°C.

4. The production process according to claim 2, characterized in that: In step 2), the gas phase separated by the first gas-liquid separator (8) and the second gas-liquid separator (10) enters a falling film absorption tower for absorption to produce hydrochloric acid. After the falling film absorption tower, an alkali liquid absorption tower is installed to absorb the unreacted chlorine gas. A vacuum pump is then used to evacuate the gas so that a slight negative pressure of 4 to 10 mmHg is formed in the system.

5. The production process according to claim 2, characterized in that: In the steps 3) and 4), the temperature of the first evaporation kettle (11) and the second evaporation kettle (12) is controlled at 90-105°C.

Images