A kind of preparation method of 3-bromo-1-propanol
By performing continuous reactions in the microchannel reactor, the reaction conditions such as temperature, molar ratio and reaction time are controlled, and the problems of 3-bromo-1-propanol in the prior art are solved, and the preparation effect of high efficiency and low by-products is achieved.
Patent Information
- Application Number
- CN202411912032.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-04-01
AI Technical Summary
The prior art has problems such as long reaction time, many by-products, low reaction selectivity and low yield when preparing 3-bromo-1-propanol, and the steps are complicated and not suitable for large-scale industrial production.
The continuous reaction was carried out using a microchannel reactor. By mixing the aqueous hydrobromic acid solution with a mixture of 1,3-propylene glycol and toluene in a batching kettle, the reaction temperature was controlled to be 80-110°C, the molar ratio of hydrobromic acid to 1,3-propylene glycol was 1:1-1.1, and the reaction time was 90-180s.
The efficient preparation of 3-bromo-1-propanol was achieved, with a yield of 96.3%, and a purity of up to 99.8%, which shortened the reaction time, improved the selectivity of the product, and reduced the generation of by-products.
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Figure CN119735486A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the field of chemical synthesis, and specifically relates to a method for preparing 3-bromo-1-propanol. Background Art
[0002] 3-Bromo-1-propanol is a 1,3-difunctionalized propane compound. It has a certain solubility in water and is miscible with common organic solvents. It has a variety of chemical reactivity and is mainly used as an organic synthesis intermediate. It can be used for the structural modification and synthesis of insect pheromones and propylene oxide functional organic molecules.
[0003] Chemical Reagents (Zhi Yonggang, Han Jie, Zhang Liangfu, Pan Weidong. Synthesis of 3-bromo-1-propanol [J]. Chemical Reagents, 2001, 23 (1): 46-47) discloses a synthesis of 3-bromo-1-propanol, and the synthetic route is as follows:
[0004]
[0005] Reagents and conditions: (a) HBr / HOAc, room temperature; (b) H + -Cation exchange resin, CH 3 OH reflux, 16h, yield 95%; this method uses 1,3-propylene glycol as raw material, acetic acid, methanol through bromination esterification, deesterification two-step reaction, although the yield is improved, but requires specific cation exchange resin, and the steps are cumbersome and time-consuming, which is not suitable for large-scale industrial production.
[0006] Patent CN 1543451 A discloses a method for synthesizing 3-bromo-1-propanol. In the presence of benzene as a solvent, 1,3-propanediol is reacted with hydrobromic acid to obtain 3-bromo-1-propanol. However, the reaction is time-consuming, produces many by-products, has low reaction selectivity, low reaction yield, and complicated post-processing.
[0007] In view of the shortcomings of the existing technology, the market needs a safe and efficient preparation method for producing 3-bromo-1-propanol. Summary of the invention
[0008] Purpose of the invention: The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art and provide a method for preparing 3-bromo-1-propanol. To achieve the above-mentioned purpose, the technical solution provided by the present invention is as follows:
[0009] The present application provides a method for preparing 3-bromo-1-propanol, which comprises the following steps:
[0010] Step 1: preparing a hydrobromic acid aqueous solution in a batching kettle;
[0011] Step 2: 1,3-propylene glycol and toluene are respectively transported to a continuous batching kettle by metering pumps to mix to obtain a mixed solution A;
[0012] Step 3: controlling the preheating temperature of the microchannel reactor, adjusting the flow rates of the hydrobromic acid aqueous solution and the mixed solution A, and pumping them into the microchannel reactor to react and form a reaction solution, the reaction temperature is 80 to 110° C., and the molar ratio of hydrobromic acid to 1,3-propylene glycol in the reaction solution is in the range of 1:1 to 1.1;
[0013] Step 4: After the reaction materials flow out of the microchannel reactor, post-treatment is performed to obtain 3-bromo-1-propanol.
[0014] In some embodiments, the flow rate of the reaction solution is calculated based on the molar ratio of hydrobromic acid to 1,3-propylene glycol in the reaction solution and the molar concentration of 1,3-propylene glycol in the mixed solution A.
[0015] In some embodiments, in step 2, the molar concentration of 1,3-propylene glycol in the mixed solution A is in the range of 0.5 to 2.5 mol / L.
[0016] In some embodiments, in step 3, the preheating temperature of the microchannel reactor is in the range of 80 to 110°C.
[0017] In some embodiments, in step 3, the reaction time is 90 to 180 seconds.
[0018] In some embodiments, in step 4, the post-treatment method is: distillation under reduced pressure, recovering toluene, and collecting 3-bromo-1-propanol.
[0019] In some embodiments, the conditions for recovering toluene are 37-38° C., 35 mmHg; the conditions for collecting 3-bromo-1-propanol are 80-81° C., 10 mmHg.
[0020] In some embodiments, in step 1, the concentration of the hydrobromic acid aqueous solution is 45-48 wt %, preferably 48 wt %.
[0021] In some embodiments, the metering pump is a peristaltic pump, a diaphragm pump, or a plunger pump.
[0022] In some embodiments, the material of the microchannel reactor is silicon carbide, PTFE, Hastelloy, Monel or titanium.
[0023] In some embodiments, the inner diameter of the microchannel reactor is 0.5-5 mm.
[0024] Beneficial effects: The present invention uses 1,3-propylene glycol and hydrobromic acid as raw materials, and continuously reacts in a microchannel reactor to prepare 3-bromo-1-propanol. Since the inner diameter of the microchannel reactor reaches the millimeter level, the specific surface area of contact between the materials is increased, and at the same time, it has a good heat transfer effect, shortens the reaction time, avoids the formation of by-products caused by inaccurate temperature control and long reaction time in conventional reactions, improves the selectivity of the product, and realizes the efficient preparation of 3-bromo-1-propanol. The reaction conditions for preparing 3-bromo-1-propanol by using a microchannel reactor are studied, and the reaction temperature is screened to be 80 to 1 When the temperature is 10°C, the molar ratio of hydrobromic acid:1,3-propylene glycol in the reaction solution is in the range of 1:1 to 1.1, the molar concentration of 1,3-propylene glycol is in the range of 0.5 to 2.5 moL / L, and the reaction time is in the range of 90 to 180 s, the yield of the prepared 3-bromo-1-propanol is as high as 96.3% compared with the yield of the conventional reactor, and the purity is as high as 99.8%. The central control test found that the use of a microchannel reactor and the reaction conditions not only increased the conversion rate of 1,3-propylene glycol, but also reduced the production of by-product dihalogenated compounds. At the same time, the reaction time is shortened, avoiding the formation of coupled impurities.
[0025] The abbreviations of the reaction reagents involved in the instructions are as follows:
[0026] HBr: hydrobromic acid;
[0027] HOAc: acetic acid;
[0028] CH 3 OH: methanol. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 This is a process flow chart for preparing compound I (3-bromo-1-propanol) in Example 1. DETAILED DESCRIPTION
[0030] The present invention is further illustrated below in conjunction with specific embodiments. The embodiments are implemented based on the technical solutions of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.
[0031] Example 1
[0032] Synthesis of compound I (3-bromo-1-propanol):
[0033]
[0034] 1,3-propylene glycol and toluene are respectively transported to a continuous batching kettle by a metering pump to mix and obtain a mixed solution A, wherein the molar concentration of 1,3-propylene glycol in the mixed solution A is 1.5 mol / L. A hydrobromic acid aqueous solution is prepared in the batching kettle, and the concentration of the hydrobromic acid aqueous solution is 48%. The microchannel reactor is controlled to have a certain preheating temperature, and the flow rate of the mixed solution A is adjusted to 50 mL / min, and the flow rate of the hydrobromic acid aqueous solution is adjusted to 4 mL / min. The molar ratio of 1,3-propylene glycol and hydrobromic acid is 1:1, and they are pumped into the microchannel reactor for mixing and reaction. A certain reaction temperature is maintained and a certain time is retained.
[0035] After the reaction material flows out of the microchannel reactor, it is sampled for GC central control detection, and distilled under reduced pressure. Toluene is recovered at 37-38°C (35 mmHg), and the fraction at 80-81°C (10 mmHg) is collected to obtain 3-bromo-1-propanol. The process flow is shown in Figure 1 As shown, the material of the microchannel reactor is silicon carbide, and the inner diameter of the microchannel reactor is 0.5-5 mm. The metering pump is a peristaltic pump, a diaphragm pump or a plunger pump. The results are shown in Tables 1 and 2 below:
[0036] Table 1 Examples of preparing compound I at different reaction temperatures and reaction times
[0037]
[0038] Table 2 Comparative Examples of Compound I Prepared at Different Reaction Temperatures
[0039]
[0040] It can be seen from 1-1 to 1-4 in Table 1 and Table 2 that, under the same reaction time, as the reaction temperature increases, the conversion rate of 1,3-propylene glycol (Y1) increases, the by-products I1 and I2 are effectively reduced, and the yield and purity of 3-bromo-1-propanol are improved. However, when the temperature is too high, the central control finds that the by-product I2 has an increasing trend. The reaction temperature is suitable at 80°C to 110°C, and the yield and selectivity of compound I are good. It can be seen from 1-2, 1-5 to 1-7 in Table 1 that shortening the reaction time will lead to a lower conversion rate of 1,3-propylene glycol (Y1).
[0041] Example 2
[0042] Synthesis of compound I (3-bromo-1-propanol):
[0043]
[0044] 1,3-propylene glycol and toluene are respectively transported to a continuous batching kettle by a metering pump to be mixed to obtain a mixed solution A, wherein the molar concentration of 1,3-propylene glycol in the mixed solution A is 1.5 mol / L. A hydrobromic acid aqueous solution is prepared in the batching kettle, and the concentration of the hydrobromic acid aqueous solution is 48%. The preheating temperature of the microchannel reactor is controlled to 90°C, and the flow rate of the mixed solution A is adjusted to 4 mL / min. A certain molar ratio of 1,3-propylene glycol and hydrobromic acid is controlled, and they are pumped into the microchannel reactor for mixing and reaction. The reaction temperature is maintained at 90°C and the retention time is 150s.
[0045] After the reaction material flows out of the microchannel reactor, the sample is taken for GC control detection, and the distillation is performed under reduced pressure. Toluene is recovered at 37-38°C (35 mmHg), and the fraction at 80-81°C (10 mmHg) is collected to obtain 3-bromo-1-propanol. The material of the microchannel reactor is silicon carbide, and the inner diameter of the microchannel reactor is 0.5-5 mm. The results are shown in Tables 3 and 4 below:
[0046] Table 31, the effect of the molar ratio of 3-propylene glycol to hydrobromic acid on the reaction
[0047]
[0048] Table 41, the effect of the molar ratio of 3-propylene glycol to hydrobromic acid on the reaction
[0049]
[0050] It can be seen from the results of Table 3 and Table 4 that when the molar ratio of hydrobromic acid: 1,3-propylene glycol is between 1:1 and 1.1, the yield and purity of compound I are high, and the selectivity is good. In the central control test, the content of by-products I1 and I2 is relatively small, but when 1,3-propylene glycol is a little more, the conversion rate decreases. However, when the equivalent of 1,3-propylene glycol is less than that of hydrobromic acid, it can be seen from the central control test that the content of dihalogenated compounds in the by-product compound I1 is significantly increased. Therefore, when the molar ratio of hydrobromic acid: 1,3-propylene glycol is between 1:1 and 1.1, the reaction effect is best.
[0051] Example 3
[0052] Synthesis of compound I (3-bromo-1-propanol):
[0053]
[0054] 1,3-propylene glycol and toluene are respectively transported to a continuous batching kettle by a metering pump to mix to obtain a mixed solution A, and the molar concentration of 1,3-propylene glycol in the mixed solution A is adjusted by the amount of toluene. A hydrobromic acid aqueous solution is prepared in the batching kettle, and the concentration of the hydrobromic acid aqueous solution is 48%. The preheating temperature of the microchannel reactor is controlled to 90°C, and the flow rate of the mixed solution A is adjusted to 4mL / min. The molar ratio of 1,3-propylene glycol and hydrobromic acid is 1.05:1, and they are pumped into the microchannel reactor for mixing and reaction. The reaction temperature is maintained at 90°C and the retention time is 150s.
[0055] After the reaction material flows out of the microchannel reactor, the sample is taken for GC control detection, and the distillation is performed under reduced pressure. Toluene is recovered at 37-38°C (35 mmHg), and the fraction at 80-81°C (10 mmHg) is collected to obtain 3-bromo-1-propanol. The process flow is shown in the figure. The material of the microchannel reactor is silicon carbide, and the inner diameter of the microchannel reactor is 0.5-5 mm. The results are shown in Table 5 below:
[0056] Table 51, the effect of the concentration of 3-propylene glycol on the reaction
[0057]
[0058] It can be seen from the results in Table 5 that when the molar concentration of 1,3-propylene glycol is small, the flow rate will increase in a short time, resulting in incomplete reaction and a lower conversion rate of 1,3-propylene glycol. When the molar concentration is too high, the corresponding flow rate slows down, resulting in the coupling of the product with impurity I1 to form impurity I2. The corresponding impurity I2 content increases during the intermediate control.
[0059] Comparative Example 4 (conventional reactor)
[0060] Synthesis of compound I (3-bromo-1-propanol):
[0061]
[0062] Into a four-necked flask, 100 g (1.314 mol, 1.05 eq) of 1,3-propylene glycol, 876 mL of toluene, and 211 g (1.252 mol, 1 eq) of 48% aqueous hydrobromic acid solution were added in sequence, stirring was started, and the mixture was heated to 90°C. The mixture was stirred and kept warm for 24 hours. GC control was performed for detection (Y1: 5.6%, I: 66.1%, I1: 21.5%, I2: 6.4%). The mixture was distilled under reduced pressure, toluene was recovered at 37-38°C (35 mmHg), and the fraction at 80-81°C (10 mmHg) was collected to obtain 77.6 g of 3-bromo-1-propanol with a GC purity of 91.5% and a yield of 40.8%. The results are shown in Table 6 below.
[0063] Table 6 Comparative Examples of Compound I Prepared by Conventional Reactor
[0064]
[0065] From the results in Table 6, it can be seen that when using a conventional reactor, even under the conditions of optimal parameters, the yield is only 40%, the selectivity is not good, and the contents of by-products I1 and I2 are high in the central control detection. At the same time, compared with conventional reactors, microchannel reactors have good temperature control, short reaction time, high product yield, and avoid the generation of more by-products.
[0066] The above specific implementation methods further illustrate the purpose, technical solutions and beneficial effects of the present application in detail. It should be understood that the above are only specific implementation methods of the present application and are not used to limit the protection scope of the present application. Any modifications, equivalent substitutions, improvements, etc. made on the basis of the technical solutions of the present application should be included in the protection scope of the present application.
Claims
1. A method for preparing 3-bromo-1-propanol, characterized in that: The following steps are involved: Step 1: preparing a hydrobromic acid aqueous solution in a batching kettle; Step 2: 1,3-propylene glycol and toluene are respectively transported to a continuous batching kettle by metering pumps to mix to obtain a mixed solution A; Step 3: controlling the preheating temperature of the microchannel reactor, adjusting the flow rates of the hydrobromic acid aqueous solution and the mixed solution A, and pumping them into the microchannel reactor to react and form a reaction solution, the reaction temperature is 80 to 110° C., and the molar ratio of hydrobromic acid to 1,3-propylene glycol in the reaction solution is in the range of 1:1 to 1.1; Step 4: After the reaction materials flow out of the microchannel reactor, post-treatment is performed to obtain 3-bromo-1-propanol.
2. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: In step 2, the molar concentration of 1,3-propylene glycol in the mixed solution A is in the range of 0.5 to 2.5 mol / L.
3. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: In step 3, the preheating temperature of the microchannel reactor is in the range of 80 to 110°C.
4. The method for preparing 3-bromo-1-propanol according to claim 1 or 3, characterized in that: In step 3, the reaction time is 90 to 180 seconds.
5. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: In step 4, the post-treatment method is: distillation under reduced pressure, recovering toluene, and collecting 3-bromo-1-propanol.
6. The method for preparing 3-bromo-1-propanol according to claim 5, characterized in that: The conditions for recovering toluene are 37-38° C. and 35 mmHg; the conditions for collecting 3-bromo-1-propanol are 80-81° C. and 10 mmHg.
7. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: In step 1, the concentration of the hydrobromic acid aqueous solution is 45-48 wt %.
8. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: The metering pump is a peristaltic pump, a diaphragm pump or a plunger pump.
9. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: The material of the microchannel reactor is silicon carbide, PTFE, Hastelloy, Monel or titanium.
10. The method for preparing 3-bromo-1-propanol according to claim 1, characterized in that: The inner diameter of the microchannel reactor is 0.5-5 mm.