A device and method for continuously preparing triphosgene

Abstract

The present invention provides a device and method for continuously preparing triphosgene. The device comprises a reactor and an ultraviolet light emitting device arranged outside the reactor. The number of the reactors is at least two. The reactor comprises a packing layer and an adjustable flow material receiving device arranged in sequence from top to bottom. The bottom of the adjustable flow material receiving device is provided with a solenoid valve. The device occupies a small area and has a high degree of automation. The method has a short reaction time and can realize continuous preparation of triphosgene.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical synthesis, and in particular to a device and method for continuously preparing triphosgene. Background Art

[0002] Triphosgene (BTC), also known as solid phosgene, is an important synthetic intermediate used in the synthesis of chloroformates, isocyanates, polycarbonates, and acyl chlorides. It is also used in the synthesis of azlocillin, mezlocillin, piperacillin, enalapril, and other antihypertensive drugs. It can also be used in the manufacture of carbamate pesticides, urea herbicides, synthetic herbicides, and insecticides. Triphosgene is also a key intermediate in the production of antibiotics and other drugs, and a crucial raw material for the synthesis of polyurethane foam plastics.

[0003] Synthetic triphosgene is synthesized from dimethyl carbonate (DMC) and chlorine through a chlorination reaction initiated by light, heat or an initiator. The synthesis process mainly includes carbon tetrachloride solvent method and dimethyl carbonate bulk method. However, the raw material carbon tetrachloride in the carbon tetrachloride solvent method is extremely destructive to the atmospheric ozone layer. The Montreal Protocol has designated it as a banned substance. Therefore, the development of non-carbon tetrachloride solvent method to prepare solid phosgene is a general trend. The dimethyl carbonate bulk method is divided into two types according to the different initiation methods: (1) using peroxides and azo initiators to initiate the reaction; (2) using ultraviolet light to initiate the reaction. However, the use of peroxides and azo initiators requires particularly high control conditions such as the amount of initiator, addition rate and reaction temperature. Furthermore, the initiator will remain in the product, affecting the product quality. Using ultraviolet light as an initiator will not cause pollution to the synthetic product, so it has great advantages over using organic matter as an initiator.

[0004] Domestic triphosgene synthesis processes primarily utilize glass reactors and enameled kettles as reaction vessels. When the enameled glass reactor falls off, metals contained within the reactor shell can promote the decomposition of solid phosgene, posing a significant safety hazard. Batch glass reactors increase production capacity by increasing the number of reactor sets. However, their drawbacks include large floor space, low automation, and cumbersome manual operation.

[0005] CN205367743U discloses a device for generating phosgene for synthesizing difluorobenzophenone, including an anti-corrosion blower, a purifier and a phosgene generator; the phosgene generator includes a housing, a gas mixing chamber, a catalyst layer and a phosgene collecting chamber; the gas mixing chamber is located in the upper half of the housing, the phosgene collecting chamber is located in the lower half of the housing, and the catalyst layer is located between the gas mixing chamber and the phosgene collecting chamber. The generating device changes the traditional shell and tube reaction mode to a mode of directly mixing the reaction using a phosgene generator, so that carbon monoxide gas and chlorine gas are fully mixed in the gas mixing chamber and then generate difluorobenzophenone when passing through the catalyst layer, with a simple structure and high efficiency. However, the generating device needs to be separately provided with a purifier to purify phosgene, and the cost of phosgene generation is high.

[0006] CN109395683A discloses a solid phosgene synthesis device and method. The device comprises multiple reactors connected in series, each reactor comprising: a reactor shell, equipped with a liquid material feed port, a gas material feed port, a material discharge port, and an exhaust gas discharge port. The discharge port of the upper reactor is connected to the liquid material feed port of the lower reactor connected in series, and the height of the discharge port of the upper reactor is not lower than that of the lower reactor; a reactor liner provided on the inner wall of the reactor shell; a heat conduction system provided in the reactor cavity; a gas distributor provided at the bottom of the reactor cavity; and an ultraviolet light source provided at the top of the reactor shell. This device continuously synthesizes solid phosgene while ensuring safety. However, the intermittent material transfer between the serial reactors in this device results in a long reaction time and a large floor space.

[0007] CN106984253A discloses a solid phosgene synthesis device, which includes three reactors connected in series from left to right, with the height of the three reactors decreasing from left to right. Each reactor includes a reactor shell, a liquid feed port, a gas feed port, a material discharge port, and an exhaust gas discharge port provided in the reactor shell, a heat transfer system for controlling the temperature of the reactor's inner cavity, and an ultraviolet light source with adjustable wavelength and power installed in the reactor's inner cavity, wherein the wavelength of the ultraviolet light source is 200 to 400 nm. The device has the advantages of reasonable design, simple structure, and easy use. However, the solid phosgene synthesis device has the problems of large chlorine consumption and long reaction time.

[0008] Therefore, it is of great significance to develop an apparatus and method for producing high-purity phosgene in a continuous, stable and rapid manner with minimal footprint and while ensuring safety. Summary of the Invention

[0009] In view of the problems existing in the prior art, the present invention provides a device and method for continuously preparing triphosgene. The device adopts a multi-stage direct series reactor, has a small footprint, a high degree of automation, and can realize the continuous preparation of triphosgene. The method adopts a dimethyl carbonate bulk method and uses ultraviolet light to initiate the reaction, and the reaction time is short.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In the first aspect, the present invention provides a device for continuously preparing triphosgene, which includes a reactor and an ultraviolet light emitting device arranged outside the reactor. The number of the reactors is at least two, and the reactor includes a packing layer and an adjustable flow receiving device arranged in sequence from top to bottom, and a solenoid valve is provided at the bottom of the adjustable flow receiving device.

[0012] The device for continuously preparing triphosgene described in the present invention uses multi-stage reactors directly connected in series, without the need for pipeline connection in the middle, and the device occupies a small area; an adjustable flow receiving device provided at the bottom of the reactor can not only store the generated intermediate, but also strictly control the flow of the intermediate entering the next reactor through a solenoid valve provided at the bottom, thereby achieving continuous, rapid and stable preparation of high-purity and high-yield triphosgene.

[0013] Preferably, the reactor is made of quartz glass.

[0014] Preferably, the height-to-diameter ratio of the reactor is 10:1 to 40:1, for example, it can be 10:1, 12:1, 15:1, 20:1, 25:1, 30:1, 35:1, 37:1 or 40:1.

[0015] When at least two reactors are connected in series in the present invention, to ensure complete conversion of the feedstock and maximize the reaction yield, the aspect ratio of the lower reactor should be greater than that of the upper reactor. Considering both reaction energy consumption and equipment cost, it is preferred that the reactors in series have the same aspect ratio.

[0016] Preferably, the outside of the reactor is provided with a jacket.

[0017] Preferably, the medium introduced into the jacket includes any one of water or heat transfer oil.

[0018] Preferably, the medium is water.

[0019] In the present invention, the medium introduced into the jacket is preferably water, because the maximum temperature of the chlorination reaction of the present invention does not exceed 90° C., and the reactor can reach this temperature by using water as the medium introduced into the jacket. Compared with using heat transfer oil as the medium introduced into the jacket, it can save the cost of preparing triphosgene and simplify the operation.

[0020] Preferably, the material of the filler in the filler layer includes quartz glass.

[0021] Preferably, the shape of the filler in the packing layer includes any one of spring shape, spherical shape or wire mesh shape or a combination of at least two of them, wherein typical but non-limiting combinations include a combination of spring shape and spherical shape, a combination of spring shape and wire mesh shape, a combination of spherical shape and wire mesh shape or a combination of spring shape, spherical shape and wire mesh shape.

[0022] Preferably, the height of the packing layer is 200-400 mm, for example, 200 mm, 230 mm, 250 mm, 300 mm, 350 mm, 370 mm or 400 mm.

[0023] Preferably, a filler barrier device is provided at the bottom of the filler layer.

[0024] Preferably, the material of the filler barrier device includes quartz glass.

[0025] Preferably, the distance between the adjustable flow receiving device and the packing layer is 30-100 mm, for example, 30 mm, 40 mm, 50 mm, 80 mm, 90 mm, 97 mm or 100 mm.

[0026] The present invention preferably has a spacing of 30 to 100 mm between the adjustable flow receiving device and the packing layer, providing sufficient storage space for the generated intermediates without contact between the intermediates generated in the continuous preparation process and the packing layer, thereby greatly reducing the reaction space between the raw intermediates and chlorine.

[0027] When at least two reactors are connected in series in the present invention, the shape of the packing in each reactor packing layer, the height of the packing layer and the distance between the adjustable flow receiving device and the packing layer can be the same or different.

[0028] Preferably, the distance between the ultraviolet light emitting device and the reactor is 80-120 mm, for example, 80 mm, 90 mm, 100 mm, 110 mm or 120 mm.

[0029] Preferably, the ultraviolet light emitting device includes an ultraviolet lamp.

[0030] Preferably, a feed port is provided at the top of the reactor.

[0031] Preferably, a product discharge port is provided at the bottom of the reactor.

[0032] In the present invention, the connected reactors are directly connected in series from top to bottom, that is, the product discharge port of the upper reactor is connected to the feed port of the next reactor, and no pipeline connection is required in between. The device for continuously preparing triphosgene according to the present invention is preferably used as a laboratory instrument.

[0033] Preferably, a chlorine gas outlet and a heat preservation medium outlet are respectively provided on the upper portion of the side wall of the reactor.

[0034] Preferably, a chlorine gas inlet and a heat preservation medium inlet are respectively provided at the lower portion of the side wall of the reactor.

[0035] Preferably, the chlorine inlet is arranged at the lower part of the packing layer.

[0036] In a second aspect, the present invention further provides a method for continuously preparing triphosgene, which is carried out using the apparatus for continuously preparing triphosgene described in the first aspect.

[0037] The method for continuously preparing triphosgene described in the present invention first allows the liquid raw material dimethyl carbonate and the gaseous raw material chlorine to synthesize a first intermediate under the induction of ultraviolet light. The first intermediate is then accumulated in an adjustable flow receiving device. After a certain amount of the first intermediate has accumulated, the solenoid valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor, where it continues to react with chlorine to synthesize the second intermediate. The chemical reaction mechanism of the dimethyl carbonate bulk method for synthesizing triphosgene is that triphosgene can be obtained by adding six chlorine atoms to the dimethyl carbonate molecular structure. However, after a single reaction in the organic synthesis reaction, dimethyl carbonate cannot be completely converted into the product triphosgene, and a certain amount of intermediate is produced. Only by continuously reacting the intermediate with chlorine and regulating the molar ratio and temperature of the intermediate to chlorine can the product triphosgene with high purity and high yield be obtained. The method of the present invention determines whether qualified triphosgene with high purity is obtained by measuring the content of triphosgene in the second intermediate, and determines whether a further synthesis reaction is required. The flow rate of the intermediate is controlled by a solenoid valve provided at the bottom of an adjustable flow receiving device, thereby achieving continuous and automatic preparation of triphosgene, short reaction time, and high degree of automation.

[0038] Preferably, the method comprises the following steps:

[0039] (1) When the electromagnetic valve in the first reactor is closed, dimethyl carbonate and chlorine enter the reactor, and a first chlorination reaction occurs in the packing layer under the triggering of ultraviolet light to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the adjustable flow receiving device accumulates the first intermediate, the electromagnetic valve at the bottom of the adjustable flow receiving device of the first reactor is opened, so that the first intermediate continuously enters the second reactor;

[0040] (2) Initiated by ultraviolet light, the first intermediate undergoes a second chlorination reaction with chlorine to obtain a second intermediate;

[0041] (3) Determine the content of triphosgene in the second intermediate. If the content of triphosgene in the second intermediate is greater than 99%, qualified triphosgene is obtained. Otherwise, the second intermediate continuously enters the third reactor and repeats step (2) until qualified triphosgene is obtained.

[0042] The content of triphosgene in the second intermediate of the present invention is greater than 99%, for example, it can be 99.1%, 99.3%, 99.5%, 99.7% or 99.9%.

[0043] In the present invention, since hydrogen chloride gas is generated during the chlorination reaction, gas entrainment may occur, and the yield of qualified triphosgene may be lower than the 99% content of triphosgene in the intermediate.

[0044] Preferably, the molar ratio of dimethyl carbonate to chlorine is 1:2 to 1:4, for example, 1:2, 1:2.5, 1:3, 1:3.5, 1:3.7 or 1:4.

[0045] In the present invention, dimethyl carbonate enters the reactor through a metering pump, and chlorine enters the reactor through a flow meter, thereby achieving accurate metering of the raw materials dimethyl carbonate and chlorine, strictly controlling the molar ratio of dimethyl carbonate to chlorine, and further realizing continuous preparation of triphosgene.

[0046] Preferably, the molar ratio of the second intermediate to chlorine does not exceed the molar ratio of dimethyl carbonate to chlorine.

[0047] The mol ratio of the preferred second intermediate of the present invention and chlorine is no more than the mol ratio of dimethyl carbonate and chlorine, because according to organic synthesis reaction mechanism, after dimethyl carbonate and chlorine carry out the first chlorination reaction, a certain number of chlorine atoms have been increased in the molecular structure of dimethyl carbonate, there is the intermediate having increased 1, 2, 3, 4, 5 or 6 chlorine atoms in the first intermediate, so in the processes such as the second follow-up chlorination reaction, the third chlorination reaction, too much chlorine is not needed. In the multi-stage direct series reactor in the present invention, reaction obtains qualified triphosgene, and in each reactor, the mol ratio sum between liquid raw material dimethyl carbonate and the intermediate generated and the gaseous raw material chlorine should be greater than 1:6, that is, raw material chlorine should be excessive. When the number of reactor is more, the mol ratio between liquid raw material and the gaseous raw material is more close to 1:6, that is, reaction number of times is more, and the consumption of chlorine is less, and then saves the cost of preparing triphosgene.

[0048] Preferably, the temperature of the first chlorination reaction is 10-40°C, for example, 10°C, 13°C, 15°C, 20°C, 25°C, 30°C, 35°C, 38°C or 40°C.

[0049] Preferably, the temperature of the second chlorination reaction is 50-90°C, for example, 50°C, 52°C, 55°C, 60°C, 65°C, 70°C, 80°C, 85°C or 90°C.

[0050] Preferably, the time for obtaining qualified triphosgene is 1 to 10 minutes, for example, 1 minute, 3 minutes, 5 minutes, 7 minutes, 9 minutes or 10 minutes.

[0051] Preferably, the wavelength of the ultraviolet light is 190-400 nm, for example, 190 nm, 200 nm, 230 nm, 250 nm, 300 nm, 350 nm or 400 nm.

[0052] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0053] As a preferred technical solution of the present invention, the method comprises the following steps:

[0054] (1) When the solenoid valve in the first reactor is closed, dimethyl carbonate and chlorine gas in a molar ratio of 1:2 to 1:4 enter the reactor, and a first chlorination reaction occurs in the packing layer under the conditions of ultraviolet light with a wavelength of 190 to 400 nm and a temperature of 10 to 40° C. to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the first intermediate is accumulated in the adjustable flow receiving device, the solenoid valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor;

[0055] (2) triggering by ultraviolet light having a wavelength of 190 to 400 nm, the first intermediate undergoes a second chlorination reaction with chlorine at a temperature of 10 to 40° C. to obtain a second intermediate; the molar ratio of the second intermediate to the chlorine does not exceed the molar ratio of dimethyl carbonate to the chlorine;

[0056] (3) Determine the content of triphosgene in the second intermediate. If the content of triphosgene in the second intermediate is greater than 99%, qualified triphosgene is obtained. Otherwise, the second intermediate continuously enters the third reactor and repeats step (2) until qualified triphosgene is obtained. The time for obtaining qualified triphosgene is 1 to 10 minutes.

[0057] Compared with the prior art, the present invention has at least the following beneficial effects:

[0058] (1) The continuous triphosgene preparation device provided by the present invention has a small footprint and a high level of automation, thereby improving the working environment and labor intensity of workers;

[0059] (2) The method for continuously preparing triphosgene provided by the present invention has a short reaction time and can realize continuous preparation of triphosgene. The yield of triphosgene can reach more than 97.2%, and can reach more than 98% under better conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a structural schematic diagram of the reactor in the device for continuously preparing triphosgene provided by the present invention.

[0061] In the figure: 1-feed port; 2-insulation medium outlet; 3-chlorine outlet; 4-filler barrier device; 5-chlorine inlet; 6-adjustable flow receiving device; 7-insulation medium inlet; 8-product outlet. DETAILED DESCRIPTION

[0062] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific implementation methods.

[0063] The structural diagram of the reactor in the device for continuous preparation of triphosgene provided by the present invention is as follows Figure 1 As shown, the reactor includes, from top to bottom, a packing layer and an adjustable flow material receiving device 6. A solenoid valve is provided at the bottom of the adjustable flow material receiving device 6, and a packing baffle 4 is provided at the bottom of the packing layer. A feed inlet 1 is provided at the top of the reactor; a product discharge port 8 is provided at the bottom of the reactor; a chlorine outlet 3 and an insulation medium outlet 2 are provided at the upper portion of the reactor sidewall; a chlorine inlet 5 and an insulation medium inlet 7 are provided at the lower portion of the reactor sidewall; the chlorine inlet 5 is provided at the lower portion of the packing layer.

[0064] The present invention is further described in detail below. However, the following examples are merely simplified examples of the present invention and do not represent or limit the scope of protection of the present invention. The scope of protection of the present invention shall be subject to the claims.

[0065] Those skilled in the art should understand that the present invention must include necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main invention point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0066] Example 1

[0067] This embodiment provides a device for continuously preparing triphosgene, which includes a reactor and an ultraviolet lamp arranged outside the reactor, and the distance between the ultraviolet lamp and the reactor is 100 mm.

[0068] The reactor is provided with a feed inlet at the top; a product discharge port at the bottom; a chlorine gas outlet and a heat preservation medium outlet at the upper sidewall of the reactor; a chlorine gas inlet and a heat preservation medium inlet at the lower sidewall of the reactor; and the chlorine gas inlet is located below the packing layer. There are two reactors, a first reactor and a second reactor. The product discharge port at the bottom of the first reactor is connected in series with the feed port at the top of the second reactor.

[0069] The reactor comprises, arranged from top to bottom, a packing layer, a packing baffle, and an adjustable flow rate material receiving device. A solenoid valve is installed at the bottom of the adjustable flow rate material receiving device. The reactor is made of quartz glass. A jacket is provided on the outside of the reactor; water flows into the jacket. The packing in the packing layer is made of quartz glass, and the packing baffle is also made of quartz glass.

[0070] The first reactor and the second reactor are identical, with a height-to-diameter ratio of 40:1; the shapes of the packings in the packing layer are all spring-shaped; the height of the packing layer is 300 mm; and the distance between the adjustable flow receiving device and the packing layer is 100 mm.

[0071] Example 2

[0072] This embodiment provides a device for continuously preparing triphosgene, which includes a reactor and an ultraviolet lamp arranged outside the reactor, and the distance between the ultraviolet lamp and the reactor is 80 mm.

[0073] The reactor is provided with a feed inlet at the top; a product discharge port at the bottom; a chlorine outlet and an insulation medium outlet at the upper sidewall of the reactor; a chlorine inlet and an insulation medium inlet at the lower sidewall of the reactor; and the chlorine inlet is provided at the lower portion of the packing layer. There are three reactors, namely the first reactor, the second reactor, and the third reactor. The product discharge port at the bottom of the first reactor is connected in series with the feed port at the top of the second reactor, and the product discharge port at the bottom of the second reactor is connected in series with the feed port at the top of the third reactor.

[0074] The reactor comprises, arranged from top to bottom, a packing layer, a packing baffle, and an adjustable flow rate material receiving device. A solenoid valve is installed at the bottom of the adjustable flow rate material receiving device. The reactor is made of quartz glass. A jacket is provided on the outside of the reactor; water flows into the jacket. The packing in the packing layer is made of quartz glass, and the packing baffle is also made of quartz glass.

[0075] The first reactor, the second reactor and the third reactor are identical, with a height-to-diameter ratio of 30:1; the shape of the packing in the packing layer is spring-shaped; the height of the packing layer is 400 mm; and the distance between the adjustable flow receiving device and the packing layer is 30 mm.

[0076] Example 3

[0077] This embodiment provides a device for continuously preparing triphosgene, which includes a reactor and an ultraviolet lamp arranged outside the reactor, and the distance between the ultraviolet lamp and the reactor is 120 mm.

[0078] The reactor is provided with a feed inlet at the top; a product discharge port at the bottom; a chlorine outlet and a heat preservation medium outlet are provided at the upper sidewall of the reactor; a chlorine inlet and a heat preservation medium inlet are provided at the lower sidewall of the reactor; and the chlorine inlet is provided at the lower portion of the packing layer. There are four reactors, namely the first reactor, the second reactor, the third reactor, and the fourth reactor. The product discharge port at the bottom of the first reactor is connected in series with the feed port at the top of the second reactor, the product discharge port at the bottom of the second reactor is connected in series with the feed port at the top of the third reactor, and the product discharge port at the bottom of the third reactor is connected in series with the feed port at the top of the fourth reactor.

[0079] The reactor comprises, arranged from top to bottom, a packing layer, a packing baffle, and an adjustable flow rate material receiving device. A solenoid valve is installed at the bottom of the adjustable flow rate material receiving device. The reactor is made of quartz glass. A jacket is provided on the outside of the reactor; water flows into the jacket. The packing in the packing layer is made of quartz glass, and the packing baffle is also made of quartz glass.

[0080] The first reactor, the second reactor, the third reactor and the fourth reactor are identical, with a height-to-diameter ratio of 10:1; the shape of the packing in the packing layer is spring-shaped; the height of the packing layer is 200 mm; and the distance between the adjustable flow receiving device and the packing layer is 50 mm.

[0081] Example 4

[0082] This embodiment provides a device for continuously preparing triphosgene, which includes a reactor and an ultraviolet lamp arranged outside the reactor, and the distance between the ultraviolet lamp and the reactor is 90 mm.

[0083] The reactor is provided with a feed inlet at the top; a product discharge port at the bottom; a chlorine gas outlet and a heat preservation medium outlet at the upper sidewall of the reactor; a chlorine gas inlet and a heat preservation medium inlet at the lower sidewall of the reactor; and the chlorine gas inlet is located below the packing layer. There are two reactors, a first reactor and a second reactor. The product discharge port at the bottom of the first reactor is connected in series with the feed port at the top of the second reactor.

[0084] The reactor comprises, arranged from top to bottom, a packing layer, a packing baffle, and an adjustable flow rate material receiving device. A solenoid valve is installed at the bottom of the adjustable flow rate material receiving device. The reactor is made of quartz glass. A jacket is provided on the outside of the reactor; water flows into the jacket. The packing in the packing layer is made of quartz glass, and the packing baffle is also made of quartz glass.

[0085] The first reactor has a height-to-diameter ratio of 20:1, spring-shaped packing in the packing layer, a height of 200 mm, and a 40 mm distance between the adjustable flow receiving device and the packing layer. The second reactor has a height-to-diameter ratio of 35:1, wire mesh-shaped packing in the packing layer, a height of 300 mm, and a 90 mm distance between the adjustable flow receiving device and the packing layer.

[0086] Example 5

[0087] This embodiment provides an apparatus for continuously preparing triphosgene. The apparatus is the same as that of Example 1 except that the height-to-diameter ratio of the first reactor and the second reactor is replaced from 40:1 to 5:1.

[0088] Example 6

[0089] This embodiment provides an apparatus for continuously preparing triphosgene. The apparatus is the same as that of Example 1 except that the height-to-diameter ratio of the first reactor and the second reactor is replaced from 40:1 to 50:1.

[0090] Comparative Example 1

[0091] This comparative example provides a device for continuously preparing triphosgene. The number of reactors in the device is one, and the rest are the same as those in Example 1.

[0092] Application Example 1

[0093] This application example provides a method for continuously preparing triphosgene, which is performed using the apparatus for continuously preparing triphosgene provided in Example 1. Specifically, the method includes the following steps:

[0094] (1) With the electromagnetic valve in the first reactor closed, dimethyl carbonate enters the reactor through a metering pump, and chlorine enters the reactor through a flow meter, and the molar ratio of dimethyl carbonate to chlorine is controlled to be 1:4; a first chlorination reaction occurs in the packing layer under the conditions of ultraviolet light with a wavelength of 300 nm and a temperature of 10 to 20° C. to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the first intermediate accumulates in the adjustable flow receiving device, the electromagnetic valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor;

[0095] (2) triggering by ultraviolet light with a wavelength of 200 nm, the first intermediate and chlorine gas undergo a second chlorination reaction at a temperature of 80 to 90° C. to obtain a second intermediate; the molar ratio of the second intermediate to the chlorine gas is 1:3;

[0096] (3) Determine the content of triphosgene in the second intermediate. If the content of triphosgene in the second intermediate is greater than 99%, qualified triphosgene is obtained.

[0097] Application Example 2

[0098] This application example provides a method for continuously preparing triphosgene, which is performed using the apparatus for continuously preparing triphosgene provided in Example 2. Specifically, the method includes the following steps:

[0099] (1) When the electromagnetic valve in the first reactor is closed, dimethyl carbonate enters the reactor through a metering pump, and chlorine enters the reactor through a flow meter, and the molar ratio of dimethyl carbonate to chlorine is controlled to be 1:3; under the conditions of ultraviolet light with a wavelength of 190 nm and a temperature of 20 to 30° C., a first chlorination reaction occurs in the packing layer to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the first intermediate is accumulated in the adjustable flow receiving device, the electromagnetic valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor;

[0100] (2) triggering by ultraviolet light with a wavelength of 250 nm, at a temperature of 70 to 80° C., the first intermediate and chlorine undergo a second chlorination reaction to obtain a second intermediate; the molar ratio of the second intermediate to the chlorine is 1:2;

[0101] (3) measuring the triphosgene content in the second intermediate; the triphosgene content in the second intermediate is no more than 99%, and continuously introducing the second intermediate into a third reactor. The second intermediate undergoes a third chlorination reaction with chlorine gas at a temperature of 80 to 90° C., triggered by ultraviolet light having a wavelength of 200 nm, to obtain a third intermediate; the molar ratio of the second intermediate to the chlorine gas is 1:1.8;

[0102] (4) Determine the content of triphosgene in the third intermediate. If the content of triphosgene in the third intermediate is greater than 99%, qualified triphosgene is obtained.

[0103] Application Example 3

[0104] This application example provides a method for continuously preparing triphosgene, which is performed using the apparatus for continuously preparing triphosgene provided in Example 3. Specifically, the method includes the following steps:

[0105] (1) When the electromagnetic valve in the first reactor is closed, dimethyl carbonate enters the reactor through a metering pump, and chlorine enters the reactor through a flow meter, and the molar ratio of dimethyl carbonate to chlorine is controlled to be 1:2; under the conditions of ultraviolet light with a wavelength of 400 nm and a temperature of 30 to 40° C., a first chlorination reaction occurs in the packing layer to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the first intermediate accumulates in the adjustable flow receiving device, the electromagnetic valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor;

[0106] (2) initiating a second chlorination reaction between the first intermediate and chlorine gas at a temperature of 50 to 60° C. under ultraviolet light with a wavelength of 200 nm to obtain a second intermediate; the molar ratio of the second intermediate to the chlorine gas is 1:2;

[0107] (3) measuring the content of triphosgene in the second intermediate; the content of triphosgene in the second intermediate is no more than 99%, and the second intermediate continuously enters the third reactor. The second intermediate is triggered by ultraviolet light with a wavelength of 190 nm and a temperature of 80 to 85° C. to undergo a third chlorination reaction with chlorine to obtain a third intermediate; the molar ratio of the second intermediate to the chlorine is 1:2;

[0108] (4) measuring the content of triphosgene in the third intermediate; the content of triphosgene in the third intermediate is no more than 99%, and the third intermediate continuously enters the fourth reactor. The third intermediate is triggered by ultraviolet light with a wavelength of 190 nm and a temperature of 85 to 90° C., and a fourth chlorination reaction occurs between the third intermediate and chlorine to obtain a fourth intermediate; the molar ratio of the third intermediate to the chlorine is 1:0.6;

[0109] (5) Determine the content of triphosgene in the fourth intermediate. If the content of triphosgene in the fourth intermediate is greater than 99%, qualified triphosgene is obtained.

[0110] Application Example 4

[0111] This application example provides a method for continuously preparing triphosgene, which is performed using the apparatus for continuously preparing triphosgene provided in Example 4. Specifically, the method includes the following steps:

[0112] (1) When the electromagnetic valve in the first reactor is closed, dimethyl carbonate enters the reactor through a metering pump, and chlorine enters the reactor through a flow meter, and the molar ratio of dimethyl carbonate to chlorine is controlled to be 1:4; under the conditions of ultraviolet light with a wavelength of 230 nm and a temperature of 20 to 40° C., a first chlorination reaction occurs in the packing layer to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the adjustable flow receiving device accumulates the first intermediate, the electromagnetic valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor;

[0113] (2) triggering by ultraviolet light with a wavelength of 230 nm, at a temperature of 80 to 90° C., the first intermediate undergoes a second chlorination reaction with chlorine to obtain a second intermediate; the molar ratio of the second intermediate to the chlorine is 1:3;

[0114] (3) Determine the content of triphosgene in the second intermediate. If the content of triphosgene in the second intermediate is greater than 99%, qualified triphosgene is obtained.

[0115] Application Example 5

[0116] This application example provides a method for continuously preparing triphosgene. The method is carried out using the apparatus for continuously preparing triphosgene provided in Example 5. The method is the same as that in Application Example 1.

[0117] Application Example 6

[0118] This application example provides a method for continuously preparing triphosgene. The method is carried out using the apparatus for continuously preparing triphosgene provided in Example 6. The method is the same as that in Application Example 1.

[0119] Comparative Application Example 1

[0120] This comparative example provides a method for continuously preparing triphosgene. The method is carried out using the apparatus for continuously preparing triphosgene provided in comparative example 1. The method is the same as that in application example 1.

[0121] The qualified triphosgene content in the above application examples and comparative application examples was determined by chemical titration, and the qualified triphosgene yield was calculated. The results are shown in Table 1.

[0122] Table 1

[0123]

[0124] From Table 1 we can see that:

[0125] (1) As can be seen from Examples 1 to 6, the continuous preparation method of triphosgene provided by the present invention can obtain a high yield of triphosgene in a relatively short time. The yield of triphosgene can reach more than 97.2%, and can reach more than 98% under optimal conditions.

[0126] (2) From the perspective of Application Example 1 and Application Examples 5 to 6, it can be seen that Application Example 1 is carried out using the apparatus for continuously preparing triphosgene provided in Example 1, and the aspect ratio of the first reactor to the second reactor is 40:1. Compared with Application Example 5, which is carried out using the apparatus for continuously preparing triphosgene provided in Example 5, and the aspect ratio of the first reactor to the second reactor is 5:1, and Application Example 6, which is carried out using the apparatus for continuously preparing triphosgene provided in Example 6, and the aspect ratio of the first reactor to the second reactor is 50:1, the total reaction residence time in the reactor of Application Example 1 is 2.5 min, and the yield of triphosgene is 98.1%. In Application Example 5, due to the first reactor being 100% higher than ... The height-diameter ratio of the first reactor and the second reactor is relatively small, the total reaction residence time in the reactor is relatively short, which is 1.4 min, the reaction is incomplete, and the second intermediate is not fully converted into the qualified product triphosgene. Therefore, the yield of triphosgene is low, which is 97.2%. In Application Example 6, the height-diameter ratio of the first reactor and the second reactor is relatively large, the total reaction residence time in the reactor is relatively long, which is 3.2 min, and the yield of triphosgene is also improved to 98.3%. However, the height-diameter ratio is large, and the reaction energy consumption and equipment cost will increase significantly. This shows that the present invention limits the height-diameter of the reactor to within a specific range, which can not only obtain a high yield of triphosgene, but also save preparation costs;

[0127] (3) From the comprehensive application example 1 and the application comparative example 1, it can be seen that the application example 1 is carried out using the apparatus for the continuous preparation of triphosgene provided by the application example 1, and the number of reactors is two. Compared with the application comparative example 1, the application comparative example 1 is carried out using the apparatus for the continuous preparation of triphosgene provided by the application comparative example 1, and the number of reactors is one. The total reaction residence time in the reactor of the application example 1 is 2.5 min, and the yield of triphosgene is 98.1%. However, the application comparative example 1 has only one reactor, and the total reaction residence time of the raw materials dimethyl carbonate and chlorine in the reactor is greatly reduced to only 1.2 min. The shorter the residence time, the more incomplete the chlorination reaction, and the intermediate cannot be fully converted into the product qualified triphosgene. The yield of triphosgene is only 96.7%. This shows that the number of reactors in the apparatus for the continuous preparation of triphosgene provided by the present invention is at least two, which can provide sufficient reaction time for the raw materials dimethyl carbonate and chlorine, so that the intermediate can be converted into the product qualified triphosgene as much as possible, thereby improving the yield of triphosgene.

[0128] In summary, the device and method for continuously preparing triphosgene provided by the present invention can achieve continuous preparation of triphosgene with high yield in a short reaction time. In addition, the device occupies a small area and has a high degree of automation, which greatly reduces the labor intensity of workers.

[0129] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A device for continuously preparing triphosgene, characterized in that: The device includes a reactor and an ultraviolet light emitting device arranged outside the reactor, the number of the reactors is at least two, the reactor includes a packing layer and an adjustable flow material receiving device arranged in sequence from top to bottom, and a solenoid valve is provided at the bottom of the adjustable flow material receiving device; The height-to-diameter ratio of the reactor is 10:1 to 40:1; and the distance between the adjustable flow receiving device and the packing layer is 30 to 100 mm.

2. The device according to claim 1, characterized in that The material of the reactor includes quartz glass.

3. The device according to claim 1, characterized in that The outside of the reactor is provided with a jacket.

4. The device according to claim 3, characterized in that The medium introduced into the jacket includes any one of water and heat transfer oil.

5. The device according to claim 4, characterized in that The medium is water.

6. The device according to claim 1, characterized in that The material of the filler in the filler layer includes quartz glass.

7. The device according to claim 1, characterized in that The shape of the filler in the filler layer includes any one of a spring shape, a spherical shape or a wire mesh shape, or a combination of at least two of them.

8. The device according to claim 1, characterized in that The height of the packing layer is 200-400 mm.

9. The device according to claim 1, characterized in that A packing baffle is provided at the bottom of the packing layer.

10. The device according to claim 9, characterized in that The material of the filler barrier device includes quartz glass.

11. The device according to claim 1, characterized in that The distance between the ultraviolet light emitting device and the reactor is 80 to 120 mm.

12. The device according to claim 1, characterized in that A feed port is provided on the top of the reactor.

13. The device according to claim 1, characterized in that A product discharge port is provided at the bottom of the reactor.

14. The device according to claim 1, characterized in that The upper part of the side wall of the reactor is respectively provided with a chlorine gas outlet and a heat preservation medium outlet.

15. The device according to claim 1, characterized in that A chlorine gas inlet and a heat preservation medium inlet are respectively provided at the lower portion of the side wall of the reactor.

16. The device according to claim 15, characterized in that The chlorine inlet is arranged at the lower part of the packing layer.

17. A method for continuously preparing triphosgene, characterized in that: The method is carried out using the device for continuously preparing triphosgene according to any one of claims 1 to 16.

18. The method according to claim 17, characterized in that The method comprises the following steps: (1) When the electromagnetic valve in the first reactor is closed, dimethyl carbonate and chlorine enter the reactor, and are triggered by ultraviolet light to cause a first chlorination reaction in the packing layer to obtain a first intermediate, which then enters a material receiving device with an adjustable flow rate; After the first intermediate is accumulated in the adjustable flow receiving device, the solenoid valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously flow into the second reactor; (2) Initiated by ultraviolet light, the first intermediate undergoes a second chlorination reaction with chlorine to obtain a second intermediate; (3) Determine the content of triphosgene in the second intermediate. If the content of triphosgene in the second intermediate is greater than 99%, qualified triphosgene is obtained. Otherwise, the second intermediate continuously enters the third reactor and repeats step (2) until qualified triphosgene is obtained.

19. The method according to claim 18, characterized in that The molar ratio of dimethyl carbonate to chlorine is 1:2 to 1:

4.

20. The method according to claim 18, wherein The molar ratio of the second intermediate to chlorine does not exceed the molar ratio of dimethyl carbonate to chlorine.

21. The method according to claim 18, wherein The temperature of the first chlorination reaction is 10-40°C.

22. The method according to claim 18, wherein The temperature of the second chlorination reaction is 50-90°C.

23. The method according to claim 18, wherein The time for obtaining qualified triphosgene is 1 to 10 minutes.

24. The method according to claim 18, wherein The wavelength of the ultraviolet light is 190-400 nm.

25. The method according to claim 18, wherein The method comprises the following steps: (1) When the solenoid valve in the first reactor is closed, dimethyl carbonate and chlorine gas in a molar ratio of 1:2 to 1:4 enter the reactor, and a first chlorination reaction occurs in the packing layer under the conditions of ultraviolet light with a wavelength of 190 to 400 nm and a temperature of 10 to 40° C. to obtain a first intermediate, and the intermediate enters the adjustable flow receiving device; when the first intermediate is accumulated in the adjustable flow receiving device, the solenoid valve at the bottom of the adjustable flow receiving device of the first reactor is opened to allow the first intermediate to continuously enter the second reactor; (2) triggering by ultraviolet light having a wavelength of 190 to 400 nm, the first intermediate undergoes a second chlorination reaction with chlorine at a temperature of 10 to 40° C. to obtain a second intermediate; the molar ratio of the second intermediate to the chlorine does not exceed the molar ratio of dimethyl carbonate to the chlorine; (3) Determine the content of triphosgene in the second intermediate. If the content of triphosgene in the second intermediate is greater than 99%, qualified triphosgene is obtained. Otherwise, the second intermediate continuously enters the third reactor and repeats step (2) until qualified triphosgene is obtained. The time for obtaining qualified triphosgene is 1 to 10 minutes.

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