A method for preparing tert-butyl bromoacetate by combining microchannels with molecular distillation
By combining microchannel and molecular distillation processes, the problems of low reaction efficiency and resource waste in the synthesis of tert-butyl bromoacetate have been solved, achieving efficient, safe and environmentally friendly production of tert-butyl bromoacetate and improving product yield and purity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGXI SUNWAY CHEM CO LTD
- Filing Date
- 2026-03-11
- Publication Date
- 2026-06-09
AI Technical Summary
Existing methods for synthesizing tert-butyl bromoacetate suffer from problems such as cumbersome reaction procedures, resource waste, high costs, serious environmental pollution, and safety hazards, making it difficult to achieve efficient, safe, and environmentally friendly industrial production.
A combined microchannel and molecular distillation process was employed, in which bromoacetic acid and isobutylene underwent a rapid reaction via a microchannel reactor, and the products were separated and the raw materials were recovered using molecular distillation equipment, thus achieving a closed-loop reaction.
It improved reaction speed and product yield, reduced energy consumption and production costs, ensured reaction consistency and product purity, and achieved green production.
Smart Images
Figure CN122167286A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of chemical technology, and in particular to a synthetic method for preparing tert-butyl bromoacetate by combining microchannel and molecular distillation. Background Technology
[0002] Tert-Butyl bromoacetate, as a key organic synthetic intermediate, has demonstrated extremely wide application value in various fields such as pharmaceuticals and fine chemicals. Its unique mechanism of action makes it indispensable in the synthesis of amino acids and peptides. Furthermore, tert-Butyl bromoacetate also holds an irreplaceable position in high-end chemical fields such as the preparation of cyclic polyamine and polycarboxylic acid contrast agents, the synthesis of cephalosporin antibiotics, and the development of receptor antagonists. Given its broad application prospects, research on efficient synthetic methods for tert-Butyl bromoacetate is particularly urgent and important.
[0003] Currently, there are two main methods for synthesizing tert-butyl bromoacetate. The first method involves the direct reaction of bromoacetic acid with isobutylene under solid acid catalysis, and this route has become the main approach for industrial production. However, this synthetic route has significant drawbacks, such as the cumbersome single-pot synthesis process and the high rate of non-recoverable raw materials during product separation, leading to resource waste and increased costs. The other method involves the synthesis of bromoacetyl bromide with tert-butanol under pyridine or triethylamine as an acid-binding agent. Although this method is theoretically feasible, it faces numerous practical challenges, such as the high toxicity of bromoacetyl bromide, frequent side reactions during the reaction, and difficulties in separating it from the product, resulting in low product content and yield.
[0004] More significantly, both of the aforementioned synthetic methods have stringent requirements regarding reaction equipment and production process conditions. The second method, in particular, suffers from severe corrosion of equipment due to thionyl chloride, and generates large quantities of difficult-to-treat wastewater and exhaust gases. Furthermore, the acid-binding agents used are extremely polluting to the environment, increasing production costs, consuming significant labor time, and making post-processing operations cumbersome and complex, hindering large-scale production. More importantly, these production processes pose substantial safety hazards, threatening the health and safety of operators. Therefore, developing an efficient, safe, environmentally friendly, and industrially viable process for synthesizing tert-butyl bromoacetate is of crucial practical significance for promoting the sustainable development of related fields. Summary of the Invention
[0005] In order to at least solve one of the above-mentioned technical problems, the present invention aims to provide a synthetic method for preparing tert-butyl bromoacetate by combining microchannel and molecular distillation, thereby improving production efficiency, reducing production costs, and simplifying the process.
[0006] To achieve the above objectives, the present invention provides the following technical solution:
[0007] A method for synthesizing tert-butyl bromoacetate using a combination of microchannel and molecular distillation, characterized by the following steps:
[0008] Step (1): Bromoacetic acid and isobutylene are fed into the microchannel reactor via metering pumps for reaction; the reaction temperature and reaction pressure are controlled by an external controller;
[0009] Step (2): Collect the reaction liquid flowing out of the microchannel reactor and input it into the molecular distillation equipment through a metering pump to obtain the product tert-butyl bromoacetate after separation.
[0010] Preferably, in step (1), the feed molar ratio of bromoacetic acid and isobutylene is 1:2 to 7.
[0011] Preferably, in step (1), the feed mass flow rate of bromoacetic acid is 98 to 18 times that of isobutylene.
[0012] Preferably, in step (2), the feed rate of the reaction liquid entering the molecular distillation equipment is 1 g / min to 10 g / min.
[0013] Preferably, in step (1), the residence time of bromoacetic acid and isobutylene in the microchannel reactor is 5s to 30s; the reaction temperature is 60°C to 90°C; and the reaction pressure is 1MPa to 5MPa.
[0014] Preferably, in step (2), the reaction liquid flowing out of the microchannel reactor is fed into the molecular distillation equipment by a metering pump, and the molecular distillation temperature is set to 60°C to 90°C; the unreacted isobutylene is recovered from the light components of the molecular distillation and returned to the microchannel reaction system for recycling by a pump.
[0015] Preferably, the synthesis method corresponds to a synthesis apparatus;
[0016] The synthesis apparatus includes a feeding module, a reaction module, a separation and purification module, a product collection module, and a temperature control module;
[0017] The feeding module includes a bromoacetic acid raw material tank, an isobutylene raw material tank, metering pump A, metering pump B, flow regulating valve A, and flow regulating valve B;
[0018] The reaction module includes a microchannel reactor, wherein the inner diameter of the microchannel is 10 mm to 0 mm and the length of the microchannel is 5 m to 50 m.
[0019] The separation and purification module includes a molecular distillation device, whose inlet is connected to the outlet of a microchannel reactor via a metering pump C.
[0020] The product collection module includes a product collection tank, which is connected to the main fraction outlet of the molecular distillation equipment.
[0021] The feed connection is as follows: the bromoacetic acid feed tank is connected to the first feed port of the microchannel reactor in sequence through metering pump A and flow regulating valve A, and the isobutylene feed tank is connected to the second feed port of the microchannel reactor in sequence through metering pump B and flow regulating valve B.
[0022] The temperature control module includes a PLC controller, and temperature controller A and temperature controller B connected to the controller; wherein, temperature controller A is used to control the temperature of the microchannel reactor, and temperature controller B is used to control the distillation temperature of the molecular distillation equipment.
[0023] Preferably, the microchannel reactor is provided with a back pressure valve at the outlet, which is used to regulate the reaction pressure inside the microchannel reactor.
[0024] The present invention has the following beneficial effects:
[0025] I. Increased Reaction Rate and Reduced Energy Consumption: The reactants complete the mixing reaction in a very short time within the microchannel reactor, significantly increasing the reaction rate. Due to the rapid reaction rate of bromoacetic acid and isobutylene, the efficient mass and heat transfer performance of the microreactor channels makes reaction conditions easier to control, allowing the reactants to react quickly. Compared to traditional single-stage synthesis, the reaction time is significantly shortened, thereby substantially reducing energy consumption. For example, in the embodiments, under suitable feed rate, molar ratio, temperature, and pressure conditions, the reactants react rapidly within the microchannel reactor, improving overall production efficiency and reducing energy consumption.
[0026] II. Improved Product Yield, Selectivity, and Purity: The product and reactants can be effectively separated after the reaction, effectively inhibiting the dimerization of isobutylene. Precise control of reaction conditions in the microchannel reactor reduces byproduct formation, resulting in significantly improved product yield, selectivity, and purity. Data from the examples show that the yield of tert-butyl bromoacetate can reach up to 92% under different conditions. Compared to traditional methods with low product content and low yield, this technical solution offers significant advantages.
[0027] III. Ensuring Reaction Consistency and Production Economy: Precise temperature and pressure control ensures reaction consistency and product quality. Accurate control of the reaction temperature and pressure within the microchannel reactor via an external controller allows the reaction to proceed in a stable environment, guaranteeing consistent quality for each batch. Furthermore, it enables safe and stable long-term reactions and post-processing, reducing raw material waste and defective products caused by reaction instability, thus lowering production costs and ensuring economic viability.
[0028] IV. Raw Material Recycling and Green Production: Molecular distillation allows for better separation of raw materials and products, enabling the recycling of isobutylene and bromoacetic acid, and achieving a closed-loop reaction. In this embodiment, the liquid in the storage tank is pumped into the molecular distillation equipment via a metering pump. The lighter component is tert-butyl bromoacetate, the heavier component is bromoacetic acid, and the gaseous isobutylene is reintroduced into the reaction system, making the reaction more economical and environmentally friendly. This raw material recycling method reduces raw material waste, lowers production costs, and reduces waste emissions, meeting environmental protection requirements.
[0029] V. Synergistic effect of microchannel reactor and molecular distillation: The microchannel reactor provides an efficient and controllable environment for the reaction of bromoacetic acid and isobutylene, which can quickly complete the reaction and obtain a preliminary product mixture. Molecular distillation further separates the product mixture, which not only yields high-purity tert-butyl bromoacetate, but also recovers unreacted bromoacetic acid and isobutylene, allowing them to participate in the reaction again and improving the utilization rate of raw materials. This synergistic effect cannot be achieved by a single device.
[0030] VI. Combination of precise control and closed-loop reaction: By precisely controlling parameters such as reaction temperature, pressure, feed rate and molar ratio, the high selectivity and high yield of the reaction are ensured; while molecular distillation enables the recycling of raw materials to form a closed-loop reaction, further enhancing the economy and environmental friendliness of the entire process. This combination of precise control and closed-loop reaction is the unique advantage of this technical solution. Attached Figure Description
[0031] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a process flow diagram of an embodiment of the present invention. Detailed Implementation
[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0034] like Figure 1As shown, the device mainly consists of a feeding module, a reaction module, a product collection module, a distillation module, and a temperature control module. The specific structure and connection method of each module are as follows:
[0035] The feeding module includes a bromoacetic acid feed tank and an isobutylene feed tank, each equipped with a metering pump and a flow control valve. The bromoacetic acid feed tank is connected to the first inlet of the microchannel reactor via a metering pump and piping, while the isobutylene feed tank is similarly connected to the second inlet of the microchannel reactor via a metering pump and flow control valve. The metering pumps and flow control valves allow for precise control of the feed rate and flow rate of bromoacetic acid and isobutylene, ensuring the reaction proceeds in a predetermined ratio.
[0036] The core component of the reaction module is a microchannel reactor, with microchannel inner diameters designed to be 0.10-2.0 mm and microchannel lengths ranging from 5-50 m. This microchannel structure provides a large specific surface area, enhancing mass and heat transfer, allowing reactants to react rapidly and fully within the microchannels. The microchannel reactor has a first inlet and a second inlet for introducing bromoacetic acid and isobutylene, respectively. The outlet is connected to a product storage tank via a pipe and a back pressure valve, which maintains stable pressure within the reaction system.
[0037] The product collection module is mainly a product storage tank, used to collect the reaction product tert-butyl bromoacetate solution flowing out of the outlet of the microchannel reactor.
[0038] The distillation module employs a molecular distillation apparatus, which can effectively separate the light component (tert-butyl bromoacetate), heavy component (bromoacetic acid), and gaseous isobutylene from the product based on the differences in boiling points of different substances.
[0039] The temperature control module consists of a PLC controller and a temperature controller connected to the PLC controller. The temperature controller is installed on the bromoacetic acid feed tank and the microchannel reactor to monitor and control the temperature of bromoacetic acid and the reaction temperature inside the microchannel reactor in real time. The PLC controller precisely regulates the temperature controller according to the set temperature parameters to ensure that the reaction proceeds under suitable temperature conditions.
[0040] The raw materials and reagents used in the following examples are all commercially available. The technical effects of the present invention are verified through experiments under different conditions.
[0041] Example 1
[0042] Raw material preparation and feeding
[0043] Weigh 500g of bromoacetic acid and place it in the bromoacetic acid raw material tank; at the same time, prepare isobutylene and place it in the isobutylene raw material tank.
[0044] Turn on the metering pump corresponding to the bromoacetic acid feed tank and feed bromoacetic acid into the microchannel reactor at a feed rate of 1.00 g / min; turn on the metering pump corresponding to the isobutylene feed tank and feed isobutylene into the microchannel reactor at a feed rate of 0.20 ml / min. The calculated molar ratio of bromoacetic acid to isobutylene at this point is 1:1.1.
[0045] Reaction process control
[0046] The temperature control module is used to precisely control the reaction temperature in the microchannel reactor at 80°C, while the pressure is maintained at 0.3 MPa by the pressure regulating device.
[0047] By adjusting factors such as the flow rate and pipe length of the microchannel reactor, the residence time of the reactants in the microchannel reactor is ensured to be 40 seconds, allowing bromoacetic acid and isobutylene to fully react and produce tert-butyl bromoacetate.
[0048] Product collection
[0049] After the reaction is complete, the resulting tert-butyl bromoacetate solution flows into the product storage tank through the outlet of the microchannel reactor under pressure.
[0050] Distillation Separation and Recycling
[0051] Turn on the metering pump corresponding to the product storage tank and pump the liquid in the tank into the molecular distillation equipment at an appropriate flow rate.
[0052] In molecular distillation equipment, substances are separated based on their differences in boiling points. The lighter component, tert-butyl bromoacetate, is distilled off, while the heavier component, bromoacetic acid, remains at the bottom of the distillation equipment. Gaseous isobutylene is then reintroduced into the reaction system through a specific pipeline, achieving the recycling of isobutylene.
[0053] After separation and collection, 603g of the product tert-butyl bromoacetate was obtained. Based on the theoretical yield, the yield of this example can reach 86%.
[0054] Example 2
[0055] Raw material preparation and feeding
[0056] Similarly, weigh 500g of bromoacetic acid and place it in the bromoacetic acid raw material tank, and prepare isobutylene and place it in the isobutylene raw material tank.
[0057] Turn on the metering pump and feed bromoacetic acid into the microchannel reactor at a feed rate of 1.00 g / min. Feed isobutylene into the microchannel reactor at a feed rate of 0.25 ml / min. At this time, the feed molar ratio of bromoacetic acid to isobutylene is 1:1.4.
[0058] Reaction process control
[0059] The reaction temperature is set to 80℃ using a temperature control module, and the reaction pressure is maintained at 0.3MPa using a pressure regulating device.
[0060] The residence time of the reactants in the microchannel reactor was controlled to be 40 seconds to ensure that the reaction proceeded fully.
[0061] Product collection
[0062] After the reaction was completed, the tert-butyl bromoacetate solution flowed into the product storage tank.
[0063] Distillation Separation and Recycling
[0064] The liquid in the product storage tank is pumped into the molecular distillation equipment using a metering pump.
[0065] During molecular distillation, the light component tert-butyl bromoacetate, the heavy component bromoacetic acid, and gaseous isobutylene are effectively separated, and the gaseous isobutylene is recycled back to the reaction system.
[0066] The final product obtained was 624g of tert-butyl bromoacetate, and the yield of this example can be calculated to be 89%.
[0067] Example 3
[0068] Raw material preparation and feeding
[0069] Weigh 500g of bromoacetic acid and prepare isobutylene and place them in the corresponding raw material tanks.
[0070] Bromoacetic acid was fed into the microchannel reactor at a feed rate of 1.00 g / min, and isobutylene was fed into the microchannel reactor at a feed rate of 0.25 ml / min, with a feed molar ratio of 1:1.4.
[0071] Reaction process control
[0072] Unlike the previous two embodiments, this embodiment increases the reaction temperature to 90°C while maintaining the reaction pressure at 0.3 MPa.
[0073] The residence time of the reactants was controlled to 40 seconds to promote the reaction.
[0074] Product collection
[0075] After the reaction was completed, the tert-butyl bromoacetate solution flowed into the product storage tank.
[0076] Distillation Separation and Recycling
[0077] The liquid in the product storage tank is pumped into the molecular distillation equipment for separation using a metering pump.
[0078] After separation, 645g of tert-butyl bromoacetate was obtained. The yield of this example was calculated to be 92%.
[0079] Example 4
[0080] Raw material preparation and feeding
[0081] Weigh 500g of bromoacetic acid and prepare isobutylene and place them in the raw material tank respectively.
[0082] Bromoacetic acid was fed into the microchannel reactor at a feed rate of 1.00 g / min, and isobutylene was fed into the microchannel reactor at a feed rate of 0.30 ml / min. At this time, the feed molar ratio of bromoacetic acid and isobutylene was 1:1.7.
[0083] Reaction process control
[0084] The reaction temperature was set to 80℃ and the reaction pressure to 0.3MPa using the temperature control module.
[0085] The residence time of the reactants in the microchannel reactor was controlled to be 40 s.
[0086] Product collection
[0087] After the reaction was completed, the tert-butyl bromoacetate solution flowed into the product storage tank.
[0088] Distillation Separation and Recycling
[0089] The liquid in the product storage tank is pumped into the molecular distillation equipment using a metering pump.
[0090] After separation, 638g of tert-butyl bromoacetate was obtained, and the yield of this example was calculated to be 91%.
[0091] Example 5
[0092] Raw material preparation and feeding
[0093] Weigh 1 kg of bromoacetic acid and place it in the bromoacetic acid raw material tank. Prepare isobutylene and place it in the isobutylene raw material tank.
[0094] Bromoacetic acid was fed into the microchannel reactor at a feed rate of 1.00 g / min, and isobutylene was fed into the microchannel reactor at a feed rate of 0.25 ml / min, with a feed molar ratio of 1:1.4.
[0095] Reaction process control
[0096] In this embodiment, the reaction temperature is set to 70°C and the reaction pressure is 0.3 MPa.
[0097] Extend the residence time of reactants in the microchannel reactor to 50 s to ensure a complete reaction.
[0098] Product collection
[0099] After the reaction was completed, the tert-butyl bromoacetate solution flowed into the product storage tank.
[0100] Distillation Separation and Recycling
[0101] The liquid in the product storage tank is pumped into the molecular distillation equipment for separation using a metering pump.
[0102] The final product, tert-butyl bromoacetate, was obtained in 512g. Calculations show that the yield of this example can reach 73%.
[0103] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions, or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.
Claims
1. A method for synthesizing tert-butyl bromoacetate using a combination of microchannel and molecular distillation, characterized in that: Includes the following steps: Step (1): Bromoacetic acid and isobutylene are fed into the microchannel reactor via metering pumps for reaction; the reaction temperature and reaction pressure are controlled by an external controller; Step (2): Collect the reaction liquid flowing out of the microchannel reactor and input it into the molecular distillation equipment through a metering pump to obtain the product tert-butyl bromoacetate after separation.
2. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 1, characterized in that, In step (1), the feed molar ratio of bromoacetic acid and isobutylene is 1:2 to 1.
7.
3. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 2, characterized in that, In step (1), the feed mass flow rate of bromoacetic acid is 0.98 to 1.18 times that of isobutylene feed mass flow rate.
4. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 3, characterized in that, In step (2), the feed rate of the reaction liquid entering the molecular distillation equipment is 1 g / min to 10 g / min.
5. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 4, characterized in that, In step (1), the residence time of bromoacetic acid and isobutylene in the microchannel reactor is 5s to 30s; the reaction temperature is 60°C to 90°C; and the reaction pressure is 0.1MPa to 0.5MPa.
6. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 5, characterized in that, In step (2), the reaction liquid flowing out of the microchannel reactor is sent into the molecular distillation equipment by a metering pump, and the molecular distillation temperature is set to 60°C to 90°C; the unreacted isobutylene is recovered from the light components of the molecular distillation and returned to the microchannel reaction system for recycling by a pump.
7. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 6, characterized in that, The synthesis method corresponds to a synthesis apparatus; The synthesis apparatus includes a feeding module, a reaction module, a separation and purification module, a product collection module, and a temperature control module; The feeding module includes a bromoacetic acid raw material tank, an isobutylene raw material tank, metering pump A, metering pump B, flow regulating valve A, and flow regulating valve B; The reaction module includes a microchannel reactor, wherein the inner diameter of the microchannel is 0.10 mm to 2.0 mm and the length of the microchannel is 5 m to 50 m. The separation and purification module includes a molecular distillation device, whose inlet is connected to the outlet of a microchannel reactor via a metering pump C. The product collection module includes a product collection tank, which is connected to the main fraction outlet of the molecular distillation equipment. The feed connection is as follows: the bromoacetic acid feed tank is connected to the first feed port of the microchannel reactor in sequence through metering pump A and flow regulating valve A, and the isobutylene feed tank is connected to the second feed port of the microchannel reactor in sequence through metering pump B and flow regulating valve B. The temperature control module includes a PLC controller, and temperature controller A and temperature controller B connected to the controller; wherein, temperature controller A is used to control the temperature of the microchannel reactor, and temperature controller B is used to control the distillation temperature of the molecular distillation equipment.
8. The method for synthesizing tert-butyl bromoacetate by combining microchannel and molecular distillation according to claim 7, characterized in that, The microchannel reactor is equipped with a back pressure valve at its outlet, which is used to regulate the reaction pressure inside the microchannel reactor.