Integrated device for phosgene synthesis in laboratory

Abstract

The invention relates to the field of phosgene preparation, in particular to an integrated device for phosgene synthesis in a laboratory. Comprising a heat collection type constant-temperature heating magnetic stirrer, a three-neck flask is arranged in the heat collection type constant-temperature heating magnetic stirrer, and a mercurial thermometer, a constant-pressure dropping funnel and a first snakelike condensation pipe are inserted into three bottle mouths of the three-neck flask from left to right respectively; a top outlet of the first snakelike condensation pipe is sequentially connected with a first wide-mouth glass bottle, a second wide-mouth glass bottle and a collection bottle through pipelines, a second snakelike condensation pipe is further inserted into a bottle opening of the collection bottle, and a top outlet of the second snakelike condensation pipe is sequentially connected with a third wide-mouth glass bottle and a fourth wide-mouth glass bottle through pipelines; by adopting the constant-pressure separating funnel, the pressure stability of the device in the whole synthesis process is ensured, and the product yield is effectively improved while the safety of testers is ensured. The snake-shaped condensing pipe is additionally arranged at the upper end of the collecting device, so that the contact area of cooling liquid is increased, and the yield is improved.

Description

Technical Field

[0001] The invention relates to the field of phosgene preparation, and in particular to an integrated device for laboratory phosgene synthesis. Background Art

[0002] Phosgene (COCl2), also known as carbonyl chloride, is a highly toxic gas and a suffocating agent. Inhalation of phosgene can cause pulmonary edema, pneumonia, etc., which is dangerous and fatal. It was widely used in the Auschwitz concentration camp during World War II to kill prisoners of war and political prisoners. It can be used for evaluation tests of the protective performance of phosgene in protective equipment and adsorption materials. Secondly, phosgene is an important organic intermediate and a very active electrophilic reagent. It is widely used in the production of pesticides, dyes, medicines, fine chemicals and isocyanates (MDI).

[0003] The prior art has the following disadvantages: 1. The existing synthesis device is an ordinary funnel. During the synthesis process, the reaction is too fast, resulting in excessive pressure in the synthesis device. The separatory funnel cannot drip liquid, causing gas to rush out from the upper end of the separatory funnel, forcing the reaction to be interrupted, which poses certain safety hazards.

[0004] 2. The pressure in the existing synthesis device is unstable and the reaction rate cannot be controlled. The reaction rate fluctuates during the synthesis process, resulting in an extremely low phosgene gas yield.

[0005] 3. The original device has a small cooling liquid area during the collection process, and the temperature of the fume hood in winter is lower than the freezing point of impurities, resulting in low product purity and high impurities. Summary of the invention

[0006] The present invention provides an integrated device for laboratory phosgene synthesis to solve the technical problems that the synthesis process of the current phosgene synthesis device is easily interrupted, the reaction rate cannot be controlled, the product purity is low, and there are many impurities.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: an integrated device for laboratory phosgene synthesis, including a heat-collecting constant temperature heating magnetic stirrer, a three-necked flask is arranged in the heat-collecting constant temperature heating magnetic stirrer, and the three bottle mouths of the three-necked flask are respectively inserted with a mercury thermometer, a constant pressure dropping funnel and a first serpentine condenser from left to right, the inlet and outlet of the outer wall of the first serpentine condenser are connected to a first circulating water multi-purpose vacuum pump through a pipeline, and the top outlet of the first serpentine condenser is sequentially connected to a first wide-mouthed glass bottle, a second A wide-mouth glass bottle and a collecting bottle, wherein a low-temperature constant-temperature circulating water bath is placed on the outside of the collecting bottle, a second serpentine condenser is also inserted at the mouth of the collecting bottle, and a second circulating water-type multi-purpose vacuum pump is also connected to the inlet and outlet of the outer wall of the second serpentine condenser through a pipeline, and the top outlet of the second serpentine condenser is sequentially connected to a third wide-mouth glass bottle and a fourth wide-mouth glass bottle through a pipeline; wherein the first wide-mouth glass bottle, the second wide-mouth glass bottle and the third wide-mouth glass bottle are all used to hold 90% concentrated sulfuric acid, and the fourth wide-mouth glass bottle 13 is used to hold 20% NaOH.

[0008] As a further limitation of the technical solution of the present invention, the condensing medium used by the first serpentine condenser is condensed water, and the condensing medium used by the second serpentine condenser is cooling water, and the cooling water is a mixture of ethylene glycol and water in a volume ratio of 1:1.

[0009] As a further limitation of the technical solution of the present invention, the condensing medium of the low-temperature constant-temperature circulating water bath 8 is cooling water, and the cooling water is a mixture of ethylene glycol and water in a volume ratio of 1:1.

[0010] As a further limitation of the technical solution of the present invention, the lengths of the first serpentine condenser tube and the second serpentine condenser tube are both 400 mm.

[0011] Compared with the prior art, the present invention has the following beneficial effects: The present invention adopts a constant pressure dropping funnel to ensure the stability of the pressure of the device during the entire synthesis process, so that the liquid flow rate is always uniform during the entire reaction process, thereby ensuring the safety of the test personnel and effectively improving the product yield.

[0012] By adding a 400mm serpentine condenser at the upper end of the collection device, the coolant contact area was increased and the yield was improved; the laboratory temperature was controlled to be maintained above 16°C to avoid the crystallization of sulfur trioxide in the collection bottle, thus solving the problems of low yield and high impurities in the original synthesis device. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The figure is a schematic diagram of the structure of the integrated device for laboratory phosgene synthesis of the present invention.

[0014] The following are marked in the figure: 1-heat collecting constant temperature heating magnetic stirrer, 2-three-necked flask, 3-mercury thermometer, 4-constant pressure dropping funnel, 5-first serpentine condenser, 6-first circulating water multi-purpose vacuum pump, 7-collecting bottle, 8-low temperature constant temperature circulating water bath, 9-first wide-mouth glass bottle, 10-second wide-mouth glass bottle, 11-second serpentine condenser, 12-third wide-mouth glass bottle, 13-fourth wide-mouth glass bottle. DETAILED DESCRIPTION

[0015] The present invention is further described below in conjunction with specific embodiments. Example 1

[0016] An integrated device for laboratory phosgene synthesis comprises a heat-collecting constant-temperature heating magnetic stirrer 1, wherein a three-necked flask 2 is arranged in the heat-collecting constant-temperature heating magnetic stirrer 1, wherein three mouths of the three-necked flask 2 are respectively inserted with a mercury thermometer 3, a constant-pressure dropping funnel 4 and a first serpentine condenser 5 from left to right, wherein the inlet and outlet of the outer wall of the first serpentine condenser 5 are connected to a first circulating water multi-purpose vacuum pump 6 through a pipeline, and the top outlet of the first serpentine condenser 5 is sequentially connected to a first wide-mouthed glass bottle 9, a second wide-mouthed glass bottle 10 and a collecting bottle 7 through a pipeline, wherein the collecting A low-temperature constant-temperature circulating water bath 8 is placed on the outside of the collecting bottle 7, and a second serpentine condenser 11 is also inserted at the bottle mouth of the collecting bottle 7. The inlet and outlet of the outer wall of the second serpentine condenser 11 are also connected to a second circulating water-type multi-purpose vacuum pump through a pipeline, and the top outlet of the second serpentine condenser 11 is sequentially connected to a third wide-mouth glass bottle 12 and a fourth wide-mouth glass bottle 13 through a pipeline; wherein the first wide-mouth glass bottle 9, the second wide-mouth glass bottle 10 and the third wide-mouth glass bottle 12 are all used to hold 90% concentrated sulfuric acid, and the fourth wide-mouth glass bottle 13 is used to hold 20% NaOH.

[0017] Furthermore, the condensing medium used by the first serpentine condenser tube 5 is condensed water, and the condensing medium used by the second serpentine condenser tube 11 is cooling water, and the cooling water is a mixture of ethylene glycol and water in a volume ratio of 1:1.

[0018] Furthermore, the condensing medium of the low-temperature constant-temperature circulating water bath 8 is cooling water, and the cooling water is a mixture of ethylene glycol and water in a volume ratio of 1:1.

[0019] Furthermore, the lengths of the first serpentine condenser tube 5 and the second serpentine condenser tube 11 are both 400 mm.

[0020] The working process and principle of the device are as follows: the reaction reagent contained in the three-necked flask 2 is carbon tetrachloride, and the reaction reagent contained in the constant pressure dropping funnel is concentrated sulfuric acid. The generated phosgene passes through the 90% concentrated sulfuric acid in the first wide-mouthed glass bottle 9 and the second wide-mouthed glass bottle 10 to remove the impurity sulfur trioxide, and then enters the collecting bottle 7. By adding a 400mm second serpentine condenser at the upper end of the collecting bottle 7, the contact area of ​​the coolant is increased, and the phosgene yield is improved. The uncollected gas is absorbed by the 90% concentrated sulfuric acid in the third wide-mouthed glass bottle 12 at the end to absorb the overflowed sulfur trioxide gas and the 20% sodium hydroxide in the fourth wide-mouthed glass bottle 13 to absorb the overflowed phosgene.

[0021] The constant pressure dropping funnel 4 is used to keep the pressure in the reaction device stable during the entire synthesis process, so that the liquid flow rate is always uniform during the liquid separation process, which solves the safety problem that due to too fast reaction, the pressure in the reaction device is too high, the separating funnel cannot drip liquid, and the gas rushes out from the upper end of the separating funnel, forcing the reaction to be interrupted.

[0022] At the same time, the problem that the reaction rate fluctuates due to unstable pressure in the reaction device and the uncontrollable reaction rate, thereby making it impossible to collect the generated phosgene gas, is solved.

[0023] A 400mm serpentine condenser was added to the upper end of the collection device to increase the contact area between the coolant and the collected gas and control the laboratory temperature to be above 16°C. This solved the problem of the original device having a small cooling liquid area during the collection process and the fume hood temperature in winter being lower than the freezing point of impurities, resulting in low product yield and high impurities.

[0024] The purity of phosgene prepared by the above-mentioned device is 95%.

Claims

1. An integrated device for laboratory phosgene synthesis, characterized in that: The invention comprises a heat-collecting constant-temperature heating magnetic stirrer (1), wherein a three-necked flask (2) is arranged inside the heat-collecting constant-temperature heating magnetic stirrer (1), and the three necks of the three-necked flask (2) are respectively inserted with a mercury thermometer (3), a constant-pressure dropping funnel (4) and a first serpentine condenser (5) from left to right, and the inlet and outlet of the outer wall of the first serpentine condenser (5) are connected to a first circulating water multi-purpose vacuum pump (6) through a pipeline, and the top outlet of the first serpentine condenser (5) is connected to a first wide-mouthed glass bottle (9), a second wide-mouthed glass bottle (10) and a collecting bottle (7) in sequence through a pipeline, and the outer wall of the collecting bottle (7) is connected to a first wide-mouthed glass bottle (9), a second wide-mouthed glass bottle (10) and a collecting bottle (7) in sequence, and the outer wall of the collecting bottle (7) is connected to a first wide-mouthed glass bottle (9), a second wide-mouthed glass bottle (10) and a collecting bottle (7) in sequence. A low-temperature constant-temperature circulating water bath (8) is placed on the side, and a second serpentine condenser (11) is also inserted at the bottle mouth of the collecting bottle (7). The inlet and outlet of the outer wall of the second serpentine condenser (11) are also connected to a second circulating water multi-purpose vacuum pump through a pipeline. The top outlet of the second serpentine condenser (11) is connected to a third wide-mouth glass bottle (12) and a fourth wide-mouth glass bottle (13) in sequence through a pipeline; wherein the first wide-mouth glass bottle (9), the second wide-mouth glass bottle (10) and the third wide-mouth glass bottle (12) are all used to hold 90% concentrated sulfuric acid, and the fourth wide-mouth glass bottle (13) is used to hold 20% NaOH.

2. The integrated device for laboratory phosgene synthesis according to claim 1, characterized in that: The condensing medium used by the first serpentine condenser tube (5) is condensed water, and the condensing medium used by the second serpentine condenser tube (11) is cooling water, and the cooling water is a mixture of ethylene glycol and water in a volume ratio of 1:

1.

3. The integrated device for laboratory phosgene synthesis according to claim 1, characterized in that: The condensing medium of the low-temperature constant-temperature circulating water bath (8) is cooling water, and the cooling water is a mixture of ethylene glycol and water in a volume ratio of 1:

1.

4. The integrated device for laboratory phosgene synthesis according to claim 1, characterized in that: The lengths of the first serpentine condenser tube (5) and the second serpentine condenser tube (11) are both 400 mm.

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