A continuous method and apparatus for the synthesis of triphosgene
By employing temperature gradient control within a tower reactor and degassing tower treatment during the triphosgene synthesis process, the problems of low raw material utilization, low product purity, and insufficient safety in triphosgene synthesis have been solved, achieving efficient and safe continuous production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANDONG GENGCAI NEW MATERIALS TECHNOLOGY CO LTD
- Filing Date
- 2025-09-24
- Publication Date
- 2026-06-09
AI Technical Summary
Existing technologies for the synthesis of triphosgene suffer from problems such as low raw material utilization, low product purity, difficulty in controlling reactor temperature, insufficient safety, and high cost. In particular, how to ensure the safety and efficiency of the reaction during exothermic reactions has not yet been effectively resolved.
By optimizing reaction conditions and equipment design, a temperature gradient with gradually increasing temperature from bottom to top is adopted in the tower reactor. The reaction is initiated by an ultraviolet light source, and vacuum degassing is carried out in the degassing tower to control the reaction rate and temperature, avoid equipment blockage, and improve raw material utilization and product purity.
This enables efficient, safe, and continuous production of triphosgene, reducing costs, improving raw material utilization, minimizing byproduct generation, and ensuring the safety and efficiency of the reaction.
Smart Images
Figure CN121180993B_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of fine chemical production technology, and in particular relates to a method and apparatus for continuous synthesis of triphosgene. Background Technology
[0002] In the field of chemical preparation processes, continuous production has become an important trend for improving efficiency and reducing costs.
[0003] Chinese patent application CN111217705A discloses a method for the continuous synthesis of benzyl chloroformate using a microchannel reactor, effectively solving the problems of long production time, inability to produce continuously, low safety performance, and excessive waste associated with batch reactor production. However, when applied to the synthesis of triphosgene, this method still has room for improvement in raw material utilization and product purity.
[0004] Chinese patent application CN114409543A discloses a continuous process for the preparation of triphosgene. By adding a tail gas chlorination reaction device after multiple photocatalytic chlorination reactors, the utilization rate of raw materials is improved, with chlorine utilization reaching 99%. Nevertheless, this method still faces the challenge of controlling the reactor temperature in actual production, especially when handling exothermic reactions. Ensuring the safety and efficiency of the reaction, and further optimizing raw material consumption and reducing byproduct generation, remain urgent problems to be solved.
[0005] Chinese patent document CN114409543B discloses a continuous preparation process for triphosgene, specifically: during the reaction, dimethyl carbonate is passed in series through N photocatalytic chlorination reactors. In the initial stage, the dimethyl carbonate raw material concentration is high; excessively high temperatures can lead to overly vigorous reactions or even runaway reactions resulting in carbonization. As the material enters subsequent reactors, the dimethyl carbonate concentration continuously decreases. At this point, the reaction temperature can be increased to ensure a certain reaction efficiency. In the final reactor, since the raw material has been almost entirely converted into triphosgene, whose crystallization point is 78℃, increasing the temperature prevents crystallization. Therefore, different ultraviolet photocatalytic reactor temperatures are set to effectively improve triphosgene production efficiency. However, this process requires multiple reactor stages, resulting in high reaction costs.
[0006] To address the aforementioned technical shortcomings, this application proposes an innovative method and apparatus for the continuous synthesis of triphosgene, aiming to further reduce costs, improve raw material utilization, and decrease the generation of by-products by optimizing reaction conditions and equipment design, while ensuring the safety and efficiency of the reaction, thereby achieving efficient, safe, and continuous production of triphosgene.
[0007] Therefore, there is an urgent need for a continuous synthesis method of triphosgene to achieve a safe and controllable continuous synthesis reaction process of triphosgene, while reducing costs and improving the utilization rate of raw materials. Summary of the Invention
[0008] This application aims to at least partially solve one of the technical problems in the related art. To this end, this application provides a method and apparatus for the continuous synthesis of triphosgene, which, through optimization of reaction conditions and equipment design, can reduce costs, improve the utilization rate of raw materials, reduce the generation of by-products, and at the same time ensure the safety and efficiency of the reaction, thereby achieving efficient, safe, and continuous production of triphosgene.
[0009] To achieve the above objectives, in a first aspect, this application provides a method for continuous synthesis of triphosgene, comprising the following steps:
[0010] S1. Dimethyl carbonate is continuously fed to the lower part of the reactor, while chlorine gas is continuously introduced from the bottom of the reactor.
[0011] S2, dimethyl carbonate, and chlorine are mixed in the reactor and then irradiated with an ultraviolet light source with a wavelength of 295–395 nm to initiate a reaction, generating molten triphosgene and hydrogen chloride gas; wherein the temperature in the reactor gradually increases from bottom to top, exhibiting a temperature gradient;
[0012] S3. Molten triphosgene continuously overflows into the degassing tower to remove residual hydrogen chloride under vacuum. The degassed molten triphosgene product then enters the flake section.
[0013] Preferably, the bottom temperature of the reactor is 50-65°C to slow down the initial reaction rate; the top temperature of the reactor is 85-120°C to keep the phosgene products in a molten state and prevent them from solidifying and clogging the equipment.
[0014] Preferably, the reactor has a tower structure with three to eight reaction sections at different temperatures arranged from bottom to top.
[0015] Preferably, the reactor has a tower structure with five reaction sections at different temperatures arranged from bottom to top.
[0016] Preferably, different reaction sections are equipped with corresponding jackets, and the jackets contain heat transfer oils of different heat grades. The temperature of each reaction section is independently controlled by the heat transfer oil in the corresponding jacket.
[0017] Preferably, the mass ratio of dimethyl carbonate to chlorine in the feed is 1:4.72 to 9.50.
[0018] Preferably, in step S3, molten triphosgene is guided from the reactor to the degassing tower through an overflow pipeline, and then evenly distributed by a distributor set at the top of the degassing tower before being degassed.
[0019] Preferably, the degassing tower is a falling film tower, and a film-forming internal is provided inside the degassing tower. The molten triphosgene obtained from the overflow of the reactor is distributed by a distributor and then uniformly distributed on the film-forming internal, flowing from top to bottom.
[0020] Preferably, the degassing tower operates at a temperature of 85–120°C and an operating pressure of 30–80 kPa.
[0021] Secondly, this application provides a triphosgene continuous synthesis apparatus for implementing the above-described triphosgene continuous synthesis method, the apparatus comprising:
[0022] The reactor has dimethyl carbonate introduced into the lower part and chlorine gas introduced into the bottom for chlorination under the irradiation of an ultraviolet light source with a wavelength of 295–395 nm, generating molten triphosgene and hydrogen chloride gas; wherein the temperature inside the reactor gradually increases from bottom to top, exhibiting a temperature gradient;
[0023] The degassing tower, connected to the reactor via an overflow pipeline, is used to continuously overflow molten triphosgene into the degassing tower to remove residual hydrogen chloride under vacuum, so that the degassed molten triphosgene product can enter the flake section.
[0024] Based on the above technical solution, it can be seen that the continuous synthesis method of triphosgene in this application has at least one of the following beneficial effects compared with the prior art:
[0025] 1. The continuous synthesis method of triphosgene in this application, by controlling the temperature in the reactor to gradually increase from bottom to top in a temperature gradient, can slow down the reaction rate and the intensity of the reaction, thus achieving a safe and controllable continuous synthesis reaction process of triphosgene and avoiding the problem of solidification and equipment blockage.
[0026] 2. In this application, the bottom temperature of the reactor is 50-65℃ and the top temperature is 85-120℃. The reactor is a tower structure with three to eight reaction sections with different temperatures from bottom to top. The temperature of each reaction section is independently controlled by the heat transfer oil in the corresponding jacket. The reaction temperature is gradually increased. This control method and reaction conditions can further improve the reaction efficiency and the purity of the triphosgene products while ensuring the safety and controllability of the reaction process.
[0027] 3. The continuous synthesis method of triphosgene in this application, by uniformly distributing the product through a distributor set at the top of the degassing tower and then performing falling film degassing, can effectively remove residual hydrogen chloride and ensure the quality of the triphosgene product. Attached Figure Description
[0028] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0029] Figure 1 This is a flowchart of the continuous synthesis method of triphosgene provided in this application;
[0030] Figure 2 This is a structural diagram of the triphosgene continuous synthesis apparatus provided in this application.
[0031] In the diagram: 1. Reactor; 2. Ultraviolet light source; 3. Degassing tower; 4. Distributor; 5. Vacuum pump; 6. Overflow line. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0033] The terms “first,” “second,” “third,” “fourth,” “fifth,” “sixth,” “seventh,” and “eighth,” etc. (if present), in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a particular order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein.
[0034] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, apparatus, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.
[0035] Example 1
[0036] like Figure 1 As shown in the figure, this application provides a method for continuous synthesis of triphosgene, including the following steps:
[0037] S1. Dimethyl carbonate is continuously fed to the lower part of the reactor, while chlorine gas is continuously introduced from the bottom of the reactor.
[0038] S2, dimethyl carbonate, and chlorine are mixed in the reactor and then irradiated with an ultraviolet light source with a wavelength of 295–395 nm to initiate a reaction, generating molten triphosgene and hydrogen chloride gas; wherein the temperature in the reactor gradually increases from bottom to top, exhibiting a temperature gradient;
[0039] S3. Molten triphosgene continuously overflows into the degassing tower to remove residual hydrogen chloride under vacuum. The degassed molten triphosgene product then enters the flake section.
[0040] A certain amount of dimethyl carbonate is continuously fed to the bottom of the reactor, and a certain amount of chlorine gas is introduced from the bottom of the reactor through a pipeline. After the two raw materials are mixed in the reactor, they are irradiated by an ultraviolet light source installed in the reactor to initiate a reaction, which is violently exothermic and releases hydrogen chloride gas. The specific reaction formula for the chlorination reaction is as follows:
[0041] C3H6O3 + Cl2 → C3Cl6O3 + 6HCl. The molten triphosgene generated in the reactor continuously overflows into the degassing tower. The product flows from top to bottom, and after vacuum degassing, the molten solidified triphosgene enters the downstream triphosgene flake section. Acidic waste gas from the top of the reactor and after vacuum pump negative pressure operation is sent to a post-treatment facility. The continuous triphosgene synthesis method of this application, by controlling the temperature inside the reactor to gradually increase from bottom to top, forming a temperature gradient, can slow down the reaction rate and intensity, achieving a safe and controllable continuous triphosgene synthesis process and avoiding the problem of solidification and equipment blockage. Furthermore, this process is inherently safe, ensures complete material reaction, minimizes on-site fugitive emissions, and saves labor costs.
[0042] Preferably, the bottom temperature of the reactor is 50–65°C to slow down the initial reaction rate; the top temperature of the reactor is 85–120°C to keep the triphosgene products in a molten state and prevent solidification and equipment blockage. The reactor has a tower structure with three to eight reaction sections at different temperatures arranged from bottom to top. Each reaction section is equipped with a corresponding jacket, and the jacket contains heat transfer oil of different heat grades. The temperature of each reaction section is independently controlled by the heat transfer oil in the corresponding jacket, and the reaction temperature is gradually increased. This control method and reaction conditions can further improve the reaction efficiency and the purity of the triphosgene products while ensuring the safety and controllability of the reaction process.
[0043] Furthermore, the reactor is configured with three reaction sections at different temperatures from bottom to top: the bottom temperature is 50–65°C, the middle temperature is 65–85°C, and the top temperature is 85–120°C, with the temperature within the reactor increasing uniformly from bottom to top. Preferably, the bottom temperature is 65°C, the middle temperature is 80°C, and the top temperature is 95°C. To ensure the reactor temperature meets requirements, three different grades of heat transfer oil systems are used, resulting in a product with acceptable quality. Preferably, the reactor is configured with five reaction sections at different temperatures from bottom to top: 55–60°C, 65–70°C, 75–80°C, 85–90°C, and 95–120°C, with the temperature increasing uniformly from bottom to top. Preferably, the different temperatures are 55°C, 65°C, 75°C, 85°C, and 95°C. To ensure the reactor temperature meets requirements, five different grades of heat transfer oil systems are used, resulting in a product with acceptable quality.
[0044] Preferably, the reactor has eight reaction sections with different temperatures arranged from bottom to top, namely 50–55℃, 56–61℃, 62–67℃, 68–73℃, 74–79℃, 80–85℃, 86–91℃, and 92–97℃, with the temperature inside the reactor increasing uniformly from bottom to top. More preferably, the temperatures are 55℃, 61℃, 67℃, 73℃, 79℃, 85℃, 91℃, and 97℃. To ensure that the temperature inside the reactor meets the requirements, eight different grades of heat transfer oil systems are used, and the resulting product quality meets the requirements.
[0045] Experimental comparisons revealed that the more reaction sections with different temperatures, the shorter the residence time, the faster the reaction rate, and the higher the production load under the same reactor size conditions. Furthermore, more temperature sections resulted in a shorter melting range and better product quality. However, it should be noted that more reaction sections with different temperatures require more independent heat transfer oil systems, increasing the overall investment and operating costs. Therefore, it is preferable that the reactor have five reaction sections with different temperatures from bottom to top.
[0046] Preferably, the mass ratio of dimethyl carbonate to chlorine in the feed is 1:4.72 to 9.50.
[0047] Optionally, the mass ratio of dimethyl carbonate to chlorine in the feed is 1:5.19 to 9.50.
[0048] Preferably, in step S3, molten triphosgene is guided from the reactor to the degassing tower via an overflow pipeline. After being evenly distributed by a distributor at the top of the degassing tower, it undergoes degassing treatment. The degassing tower is a falling film tower, equipped with film-forming internals. The molten triphosgene obtained from the reactor overflow is distributed by the distributor and then evenly distributed on the film-forming internals, flowing from top to bottom. The degassing tower is equipped with a vacuum pump and operates under negative pressure. The resulting acidic waste gas is then sent for further treatment. The degassing tower body is equipped with an outer jacket, through which heat transfer oil with the highest heat grade is circulated. Its temperature is greater than or equal to the temperature at the top of the reactor, used for heat preservation of the device, while ensuring that the temperature inside the degassing tower is higher than the melting point of triphosgene.
[0049] The product overflow pipeline at the top of the reactor is set as a jacketed pipe. The temperature of the heat transfer oil in the jacketed pipe is 85-120℃, which is used to ensure the fluidity of the triphosgene reaction products in the pipeline and prevent the reaction products from solidifying and adhering to the pipe wall to form blockage.
[0050] Preferably, the degassing tower operates at a temperature of 85–120°C and an operating pressure of 30–80 kPaA. More preferably, the operating pressure is 50–75 kPaA, within which the purity of the triphosgene is relatively high.
[0051] Implementation Plan 1:
[0052] Taking a plant with a production capacity of 60 t / a of triphosgene and an annual operating time of 7200 h as an example, the flow rates of dimethyl carbonate and chlorine are 2.53 kg / h and 13.13 kg / h, respectively, the mass ratio of dimethyl carbonate to chlorine feed is 1:5.18, the reactor operating temperature is 55, 65, 75, 85 and 95℃ from bottom to top in five different reaction sections, the operating pressure is atmospheric pressure, the degassing tower operating pressure is 80 kPaA, the operating temperature is 90℃, the product flow rate after degassing is 8.51 kg / h, the acid gas flow rate at the reactor outlet is 5.57 kg / h, and the acid gas flow rate after the vacuum pump is 1.58 kg / h.
[0053] Implementation Plan 2:
[0054] Based on the device in Implementation Scheme 1, only the operating pressure of the degassing tower is adjusted to 70 kPaA, the flow rate of the degassed product is 8.42 kg / h, the flow rate of the acid gas at the reactor outlet is 5.57 kg / h, and the flow rate of the acid gas after the vacuum pump is 1.66 kg / h.
[0055] Implementation Scheme 2, based on Implementation Scheme 1, reduced the operating pressure of the degassing tower and increased the system vacuum, resulting in a significant decrease in the solubility of residual hydrogen chloride gas in the molten triphosgene. Consequently, the hydrogen chloride gas originally dissolved in the molten triphosgene was extracted, leading to an increase in the acid gas flow rate of the vacuum pump (the acid gas flow rate after the vacuum pump increased from 1.58 kg / h to 1.66 kg / h). This also directly resulted in an increase in the actual purity of the triphosgene product and a decrease in the total product mass (the product flow rate after degassing decreased from 8.51 kg / h to 8.42 kg / h).
[0056] Therefore, it is shown that appropriately reducing the operating pressure of the degassing tower within a certain operating pressure range helps to improve the purity of triphosgene products. However, it should be noted that the minimum operating pressure of the degassing tower is 30 kPaA. The lower the operating pressure, the lower the boiling point of triphosgene; if the operating pressure is below 30 kPaA, the volatilization loss of triphosgene will increase sharply.
[0057] Implementation Plan 3:
[0058] Taking a plant with a production capacity of 200 t / a of triphosgene and an annual operating time of 7200 h as an example, the flow rates of dimethyl carbonate and chlorine are 8.43 kg / h and 41.92 kg / h, respectively, the mass ratio of dimethyl carbonate to chlorine feed is 1:4.97, the reactor operating temperatures from bottom to top are 55, 65, 75, 85 and 95 °C, the operating pressure is atmospheric pressure, the degassing tower operating pressure is 65 kPaA, the operating temperature is 90 °C, the product flow rate after degassing is 27.89 kg / h, the acid gas flow rate at the reactor outlet is 18.13 kg / h, and the acid gas flow rate after the vacuum pump is 4.33 kg / h.
[0059] Implementation Plan 4:
[0060] Based on the device in Implementation Scheme 3, only the operating pressure of the degassing tower was adjusted to 75 kPaA, the flow rate of the degassed product was 27.98 kg / h, the flow rate of the acid gas at the reactor outlet was 18.13 kg / h, and the flow rate of the acid gas after the vacuum pump was 4.24 kg / h.
[0061] Implementation Scheme 4, based on Implementation Scheme 3, increases the operating pressure of the degassing tower and reduces the system vacuum, leading to an increase in the solubility of residual hydrogen chloride gas in the molten triphosgene. As a result, more hydrogen chloride gas dissolves in the molten triphosgene, thus reducing the acid gas flow rate of the vacuum pump (the acid gas flow rate after the vacuum pump decreases from 4.33 kg / h to 4.24 kg / h). This also directly leads to a decrease in the actual purity of the triphosgene product and an increase in the total product mass (the product flow rate after degassing increases from 27.89 kg / h to 27.98 kg / h).
[0062] Implementation Scheme 4, based on Implementation Scheme 3, increases the degassing tower operating pressure by 10 kPaA. The post-degassing product flow rate increases by 0.09 kg / h, essentially due to the retained hydrogen chloride impurities. However, increasing the degassing tower operating pressure by 10 kPaA achieves a significant reduction in energy consumption, saving costs, and also enhancing system stability. Therefore, this indicates that a degassing tower operating pressure in the range of 50–75 kPaA helps improve the purity of triphosgene products while ensuring system stability and cost savings.
[0063] Based on Implementation Plan 1, Implementation Plan 3 expands the synthesis scale of triphosgene and conducts scale verification, showing that the continuous synthesis method of triphosgene remains stable after scale-up, proving the scalability of the process.
[0064] Example 2
[0065] like Figure 2 As shown in the embodiment of this application, a continuous triphosgene synthesis apparatus for implementing the above-described continuous triphosgene synthesis method is provided. The apparatus includes:
[0066] Reactor 1 is introduced into the lower part with dimethyl carbonate (DMC) and into the bottom with chlorine gas, for chlorination reaction under the irradiation of ultraviolet light source 2 with a wavelength of 295–395 nm, to generate molten triphosgene and hydrogen chloride gas; wherein the temperature inside the reactor gradually increases from bottom to top, showing a temperature gradient;
[0067] The degassing tower 3 is connected to the reactor 1 via the overflow pipeline 6. It is used to continuously overflow molten triphosgene to the degassing tower 4 to remove residual hydrogen chloride, so that the degassed molten triphosgene product can enter the flake section.
[0068] Combined with appendix Figure 2 The main structure of a continuous phosgene synthesis apparatus of this application includes a reactor 1 equipped with several ultraviolet light sources 2, a degassing tower 3 equipped with a vacuum pump 5 and a distributor 4, and a jacketed overflow pipeline 6 connecting the two.
[0069] A certain amount of dimethyl carbonate is continuously fed to the lower part of reactor 1, and a certain amount of chlorine gas is introduced from the bottom of reactor 1 through a pipeline. After the two raw materials are mixed in reactor 1, they are irradiated by ultraviolet light source 2 installed in reactor 1 to initiate a reaction, which is violently exothermic and releases hydrogen chloride gas. A temperature gradient exists in reactor 1, with the bottom temperature at 55°C and the top temperature at 95°C. The temperature gradually increases from bottom to top, with different temperatures from bottom to top being 55°C, 65°C, 75°C, 85°C, and 95°C. The temperature of each section is controlled by the temperature of the heat transfer oil in the jacket of each section. From bottom to top, these are the heat transfer oil inlet and return circuits No. 1, No. 2, No. 3, No. 4, and No. 5. The operating pressure of reactor 1 is atmospheric pressure, and the mass ratio of dimethyl carbonate to chlorine gas feed is 1:0.15 to 0.30.
[0070] Molten triphosgene generated in reactor 1 continuously overflows from reactor 1 into degassing tower 3, with the product flowing from top to bottom. Degassing tower 3 operates at a temperature of 90℃ and a pressure of 30–95 kPaA. Molten triphosgene is guided from reactor 1 to degassing tower 3 via overflow line 6, and after being evenly distributed by distributor 4 at the top of degassing tower 3, it undergoes degassing treatment. Degassing tower 3 is a falling film tower, equipped with film-forming internals. The molten triphosgene overflowing from reactor 1 is distributed by distributor 4 and evenly distributed on the film-forming internals, flowing from top to bottom. Degassing tower 3 is equipped with a vacuum pump 5, operating under negative pressure, and the resulting acidic waste gas is treated separately. Degassing tower 3 has an outer jacket, through which heat transfer oil with the highest heat grade (corresponding to heat transfer oil inlet and return circuits 6) is circulated. Its temperature is greater than or equal to the temperature at the top of reactor 1, used for equipment insulation, and simultaneously ensuring that the temperature inside degassing tower 3 is higher than the melting point of triphosgene.
[0071] After vacuum degassing, the molten solidified gas enters the downstream three-phosgene agglomeration section, while the acidic waste gas from the top of reactor 1 and after vacuum pump 5 is sent for post-treatment.
[0072] In this application, the reactor bottom temperature is 50–65°C, and the reactor top temperature is 85–120°C. The reactor has a tower structure with three to eight reaction sections at different temperatures from bottom to top. The triphosgene continuous synthesis apparatus of this application, through uniform distribution by a distributor installed at the top of the degassing tower followed by falling film degassing, can effectively remove residual hydrogen chloride, ensuring the quality of the triphosgene product. The chlorination reaction formula is: C3H6O3 + Cl2 → C3Cl6O3 + 6HCl. This reaction releases a large amount of heat, and dimethyl carbonate is a Class A hazardous material. Therefore, the reaction process is very dangerous, with a high risk of fire or explosion, posing an extremely high safety hazard. The scheme proposed in this application, by controlling the temperature inside the reactor to gradually increase from bottom to top, forming a temperature gradient, can slow down the reaction rate and intensity, achieving a safe and controllable continuous synthesis reaction process of triphosgene, and also avoiding the problem of solidification and equipment blockage.
[0073] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0074] The foregoing has described specific embodiments of the present invention. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps described in the claims may be performed in a different order than that shown in the embodiments and may still achieve the desired results. Furthermore, the processes depicted in the drawings do not necessarily require the specific or sequential order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.
[0075] In the description of the embodiments of the present invention, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In the embodiments of the present invention, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, without contradiction, those skilled in the art can combine and integrate different embodiments or examples described in the embodiments of the present invention, as well as the features of different embodiments or examples.
[0076] The above embodiments are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for continuous synthesis of triphosgene, characterized in that, Includes the following steps: S1. Dimethyl carbonate is continuously fed to the lower part of the reactor, while chlorine gas is continuously introduced from the bottom of the reactor. S2, dimethyl carbonate, and chlorine are mixed in the reactor and then irradiated with an ultraviolet light source with a wavelength of 295–395 nm to initiate a reaction, generating molten triphosgene and hydrogen chloride gas; wherein the temperature in the reactor gradually increases from bottom to top, exhibiting a temperature gradient; S3. Molten triphosgene continuously overflows into the degassing tower to remove residual hydrogen chloride under vacuum. The degassed molten triphosgene product then enters the flake section. The reactor has a tower structure, with three to eight reaction sections at different temperatures arranged from bottom to top; Different reaction sections are equipped with corresponding jackets, and the jackets contain heat transfer oils of different heat grades. The temperature of each reaction section is independently controlled by the heat transfer oil in the corresponding jacket. The mass ratio of dimethyl carbonate to chlorine in the feed is 1:4.72 to 9.
50.
2. The method for continuous synthesis of triphosgene according to claim 1, characterized in that, The bottom temperature of the reactor is 50-65°C to slow down the initial reaction rate; the top temperature of the reactor is 85-120°C to keep the phosgene products in a molten state and prevent them from solidifying and clogging the equipment.
3. The method for continuous synthesis of triphosgene according to claim 2, characterized in that, The reactor has a tower structure with five reaction sections at different temperatures arranged from bottom to top.
4. The method for continuous synthesis of triphosgene according to claim 1, characterized in that, In step S3, molten triphosgene is guided from the reactor to the degassing tower through the overflow pipeline. After being evenly distributed by the distributor set at the top of the degassing tower, it is degassed.
5. The method for continuous synthesis of triphosgene according to claim 4, characterized in that, The degassing tower is a falling film tower, and a film-forming internal is installed inside the degassing tower. The molten triphosgene obtained from the overflow of the reactor is distributed by the distributor and then uniformly distributed on the film-forming internal, flowing from top to bottom.
6. The method for continuous synthesis of triphosgene according to claim 5, characterized in that, The degassing tower operates at a temperature of 85–120°C and a pressure of 30–80 kPa.
7. A continuous triphosgene synthesis apparatus for implementing the continuous triphosgene synthesis method according to any one of claims 1-6, characterized in that, The apparatus includes: a reactor, into which dimethyl carbonate is introduced at the bottom and chlorine gas is introduced at the bottom, for carrying out a chlorination reaction under irradiation with an ultraviolet light source with a wavelength of 295–395 nm to generate molten triphosgene and hydrogen chloride gas; wherein the temperature inside the reactor gradually increases from bottom to top, exhibiting a temperature gradient; and a degassing tower, connected to the reactor via an overflow pipeline, for continuously overflowing the molten triphosgene into the degassing tower to remove residual hydrogen chloride under vacuum, so that the degassed molten triphosgene product enters the flake section.