CN118206423A - Synthesis method of 2-bromopentane - Google Patents
Synthesis method of 2-bromopentane Download PDFInfo
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- bromopentane
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- LGAJYTCRJPCZRJ-UHFFFAOYSA-N 2-bromopentane Chemical compound CCCC(C)Br LGAJYTCRJPCZRJ-UHFFFAOYSA-N 0.000 title claims abstract description 78
- 238000001308 synthesis method Methods 0.000 title claims abstract description 9
- 238000006243 chemical reaction Methods 0.000 claims abstract description 69
- YYROPELSRYBVMQ-UHFFFAOYSA-N 4-toluenesulfonyl chloride Chemical compound CC1=CC=C(S(Cl)(=O)=O)C=C1 YYROPELSRYBVMQ-UHFFFAOYSA-N 0.000 claims abstract description 56
- 239000002904 solvent Substances 0.000 claims abstract description 53
- JUJWROOIHBZHMG-UHFFFAOYSA-N Pyridine Chemical compound C1=CC=NC=C1 JUJWROOIHBZHMG-UHFFFAOYSA-N 0.000 claims abstract description 52
- HQSHAZLGVDYADJ-UHFFFAOYSA-N pentan-2-yl 4-methylbenzenesulfonate Chemical compound CCCC(C)OS(=O)(=O)C1=CC=C(C)C=C1 HQSHAZLGVDYADJ-UHFFFAOYSA-N 0.000 claims abstract description 47
- AOJFQRQNPXYVLM-UHFFFAOYSA-N pyridin-1-ium;chloride Chemical compound [Cl-].C1=CC=[NH+]C=C1 AOJFQRQNPXYVLM-UHFFFAOYSA-N 0.000 claims abstract description 46
- BBFCIBZLAVOLCF-UHFFFAOYSA-N pyridin-1-ium;bromide Chemical compound Br.C1=CC=NC=C1 BBFCIBZLAVOLCF-UHFFFAOYSA-N 0.000 claims abstract description 29
- 238000000034 method Methods 0.000 claims abstract description 26
- UMJSCPRVCHMLSP-UHFFFAOYSA-N pyridine Natural products COC1=CC=CN=C1 UMJSCPRVCHMLSP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 230000002194 synthesizing effect Effects 0.000 claims abstract description 21
- JYVLIDXNZAXMDK-UHFFFAOYSA-N pentan-2-ol Chemical compound CCCC(C)O JYVLIDXNZAXMDK-UHFFFAOYSA-N 0.000 claims description 46
- 239000012074 organic phase Substances 0.000 claims description 28
- 239000002994 raw material Substances 0.000 claims description 24
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 230000035484 reaction time Effects 0.000 claims description 10
- ZDYVRSLAEXCVBX-UHFFFAOYSA-N pyridinium p-toluenesulfonate Chemical compound C1=CC=[NH+]C=C1.CC1=CC=C(S([O-])(=O)=O)C=C1 ZDYVRSLAEXCVBX-UHFFFAOYSA-N 0.000 claims description 9
- 238000003756 stirring Methods 0.000 claims description 8
- 238000001914 filtration Methods 0.000 claims description 5
- XVMSFILGAMDHEY-UHFFFAOYSA-N 6-(4-aminophenyl)sulfonylpyridin-3-amine Chemical compound C1=CC(N)=CC=C1S(=O)(=O)C1=CC=C(N)C=N1 XVMSFILGAMDHEY-UHFFFAOYSA-N 0.000 claims description 4
- 230000001476 alcoholic effect Effects 0.000 claims description 4
- 239000003021 water soluble solvent Substances 0.000 claims description 4
- 239000012071 phase Substances 0.000 claims description 2
- 239000006227 byproduct Substances 0.000 abstract description 17
- VTOQFOCYBTVOJZ-UHFFFAOYSA-N 3-bromopentane Chemical compound CCC(Br)CC VTOQFOCYBTVOJZ-UHFFFAOYSA-N 0.000 abstract description 11
- 238000003786 synthesis reaction Methods 0.000 abstract description 11
- 238000006317 isomerization reaction Methods 0.000 abstract description 9
- -1 para-toluenesulfonic acid pyridine salt Chemical class 0.000 abstract description 9
- 238000000746 purification Methods 0.000 abstract description 5
- 239000000047 product Substances 0.000 description 31
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 21
- 230000015572 biosynthetic process Effects 0.000 description 9
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- 239000008346 aqueous phase Substances 0.000 description 6
- 238000004128 high performance liquid chromatography Methods 0.000 description 5
- 230000007935 neutral effect Effects 0.000 description 5
- 238000002360 preparation method Methods 0.000 description 5
- 238000006467 substitution reaction Methods 0.000 description 5
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- 239000012065 filter cake Substances 0.000 description 4
- 238000011065 in-situ storage Methods 0.000 description 4
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- FIQMHBFVRAXMOP-UHFFFAOYSA-N triphenylphosphane oxide Chemical compound C=1C=CC=CC=1P(C=1C=CC=CC=1)(=O)C1=CC=CC=C1 FIQMHBFVRAXMOP-UHFFFAOYSA-N 0.000 description 4
- RIOQSEWOXXDEQQ-UHFFFAOYSA-N triphenylphosphine Chemical compound C1=CC=CC=C1P(C=1C=CC=CC=1)C1=CC=CC=C1 RIOQSEWOXXDEQQ-UHFFFAOYSA-N 0.000 description 4
- 238000005406 washing Methods 0.000 description 4
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 description 3
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- 238000006677 Appel reaction Methods 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
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- ZAEQTGTVGUJEFV-UHFFFAOYSA-N phenylmethanesulfonate;pyridin-1-ium Chemical compound C1=CC=[NH+]C=C1.[O-]S(=O)(=O)CC1=CC=CC=C1 ZAEQTGTVGUJEFV-UHFFFAOYSA-N 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
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- Pyridine Compounds (AREA)
Abstract
The invention discloses a synthesis method of 2-bromopentane, and belongs to the technical field of organic synthesis. The synthesis method of the 2-bromopentane comprises the following steps: 2-amyl alcohol, p-toluenesulfonyl chloride and pyridine are reacted in a first solvent, and pentane-2-yl 4-methylbenzenesulfonate is synthesized and separated; reacting pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, synthesizing and separating to obtain 2-bromopentane. The method effectively suppresses isomerization of 2-bromopentane to 3-bromopentane. The by-product pyridine hydrochloride and the para-toluenesulfonic acid pyridine salt generated in the reaction process are easy to separate, and the environment is not polluted, so that the 2-bromopentane has high yield and high purity. The separated pyridine hydrochloride and the separated para-toluenesulfonic acid pyridine salt can meet the sales standard through simple and convenient purification treatment, and are convenient to sell or recycle, so that the full utilization of resources is realized.
Description
Technical Field
The invention relates to the technical field of organic synthesis, in particular to a synthesis method of 2-bromopentane.
Background
At present, 2-pentanol is generally used as a synthesis raw material in the synthesis of 2-bromopentane, wherein substitution of hydroxyl groups in 2-pentanol by an acidic brominating agent is a main route for synthesizing 2-bromopentane, however, 2-bromopentane is inevitably partially isomerized to 3-bromopentane under the synthesis conditions of the acidic brominating agent. Because the molecular structure and physical and chemical properties of the 2-bromopentane and the 3-bromopentane are highly similar, the two are difficult to separate by a traditional method, and the acquisition difficulty of the high-purity 2-bromopentane is remarkably increased.
To avoid isomerization of 2-bromopentane to 3-bromopentane, the related art has attempted to apply an Appel reaction to the preparation of 2-bromopentane, the 2-pentanol reacting in the environment of triphenylphosphine and CBr 4 to yield the product 2-bromopentane and by-products triphenylphosphine oxide and HCBr 3.
However, although this can effectively avoid isomerization of 2-bromopentane to 3-bromopentane, the by-product triphenylphosphine oxide is difficult to thoroughly remove from the reaction system, which affects both the yield and purity of 2-bromopentane, and the by-product HCBr 3 is extremely liable to cause environmental pollution.
Disclosure of Invention
In view of the above, the invention provides a method for synthesizing 2-bromopentane, which can solve the problems of high difficulty, high cost, easy environmental pollution and the like in the synthesis of high-purity 2-bromopentane in the related technology.
Specifically, the method comprises the following technical scheme:
A method for synthesizing 2-bromopentane, wherein the method for synthesizing 2-bromopentane comprises the following steps:
2-amyl alcohol, p-toluenesulfonyl chloride and pyridine are reacted in a first solvent, and pentane-2-yl 4-methylbenzenesulfonate is synthesized and separated;
Reacting the pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, synthesizing and separating to obtain the 2-bromopentane.
In some possible implementations, the reacting 2-pentanol, p-toluenesulfonyl chloride and pyridine in a first solvent, synthesizing and isolating pentane-2-yl 4-methylbenzenesulfonate, comprises:
Sequentially dissolving the tosyl chloride and the pyridine in the first solvent to obtain a first raw material system;
adding the 2-amyl alcohol into the first raw material system, and reacting for a first reaction time at a first reaction temperature to obtain a first product system;
Filtering the first product system and separating to obtain a first organic phase containing the pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrochloride;
Desolventizing the first organic phase to obtain the pentan-2-yl 4-methylbenzenesulfonate.
In some possible implementations, the 2-pentanol, the p-toluenesulfonyl chloride, and the pyridine are reacted in the first solvent under dry anhydrous conditions.
In some possible implementations, the first reaction temperature is 10 ℃ to 15 ℃.
In some possible implementations, the first solvent is a polar non-alcoholic solvent; and/or the number of the groups of groups,
The second solvent is a polar water-soluble solvent.
In some possible implementations, the pentan-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide are reacted in a second solvent under a weak base environment.
In some possible implementations, the weak alkaline environment is maintained by adding pyridine to the reaction system.
In some possible implementations, the reacting the pentan-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, synthesizing and isolating the 2-bromopentane, comprises:
Dissolving the pentane-2-yl 4-methylbenzenesulfonate and the pyridine hydrobromide in the second solvent to obtain a second raw material system;
Reacting the second raw material system for a second reaction time at a second reaction temperature to obtain a second product system;
Adding water into the second product system, stirring, standing for layering, and separating to obtain a second organic phase containing the 2-bromopentane and a water phase containing pyridine p-toluenesulfonate;
And rectifying the second organic phase to obtain the 2-bromopentane.
In some possible implementations, the mass ratio of the water to the pyridine hydrobromide is 1-2:1.
In some possible implementations, the second reaction temperature is 55 ℃ to 65 ℃.
The technical scheme provided by the embodiment of the invention has the beneficial effects that at least:
In the embodiment of the invention, 2-bromopentane is synthesized by a two-step method, firstly, 2-pentanol and p-toluenesulfonyl chloride are subjected to in-situ substitution reaction in the presence of weak alkaline pyridine, and an intermediate product pentane-2-yl 4-methylbenzenesulfonate and a first byproduct pyridine hydrochloride are synthesized. Then, weakly acidic and even neutral pyridine hydrobromide is further subjected to in-situ substitution reaction with pentane-2-yl 4-methylbenzenesulfonate to synthesize 2-bromopentane and a second byproduct pyridine p-toluenesulfonate, so that the synthesis of 2-bromopentane is always carried out in a neutral to weakly alkaline environment, and the isomerization of 2-bromopentane to 3-bromopentane is effectively inhibited. Meanwhile, the by-product pyridine hydrochloride and the para-toluenesulfonic acid pyridine salt generated in the reaction process are easy to separate, and the environment is not polluted, so that the 2-bromopentane has high yield and high purity. The separated pyridine hydrochloride and the separated para-toluenesulfonic acid pyridine salt can meet the sales standard through simple and convenient purification treatment, and are convenient to sell or recycle, so that the full utilization of resources is realized.
Detailed Description
In order to make the technical scheme and advantages of the present invention more apparent, the following detailed description of the embodiments of the present invention will be provided.
In order to avoid isomerization of 2-bromopentane to 3-bromopentane in the preparation of 2-bromopentane, the related art attempted to apply an Appel reaction to the preparation of 2-bromopentane, 2-pentanol was reacted under triphenylphosphine and CBr 4 to produce 2-bromopentane as a product and triphenylphosphine oxide and HCBr 3 as by-products.
However, although this can effectively avoid isomerization of 2-bromopentane to 3-bromopentane, the by-product triphenylphosphine oxide is difficult to thoroughly remove from the reaction system, which affects both the yield and purity of 2-bromopentane, and the by-product HCBr 3 is extremely liable to cause environmental pollution.
Aiming at the technical problems existing in the related technology, the embodiment of the invention provides a method for synthesizing 2-bromopentane, which comprises the following steps:
2-amyl alcohol, p-toluenesulfonyl chloride and pyridine are reacted in a first solvent, and pentane-2-yl 4-methylbenzenesulfonate is synthesized and separated. Reacting pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, synthesizing and separating to obtain 2-bromopentane.
In the embodiment of the invention, 2-bromopentane is synthesized by a two-step method, firstly, 2-pentanol and p-toluenesulfonyl chloride are subjected to in-situ substitution reaction in the presence of weak alkaline pyridine, and an intermediate product pentane-2-yl 4-methylbenzenesulfonate and a first byproduct pyridine hydrochloride are synthesized. Then, weakly acidic and even neutral pyridine hydrobromide is further subjected to in-situ substitution reaction with pentane-2-yl 4-methylbenzenesulfonate to synthesize 2-bromopentane and a second byproduct pyridine p-toluenesulfonate, so that the synthesis of 2-bromopentane is always carried out in a neutral to weakly alkaline environment, and the isomerization of 2-bromopentane to 3-bromopentane is effectively inhibited. Meanwhile, the by-product pyridine hydrochloride and the para-toluenesulfonic acid pyridine salt generated in the reaction process are easy to separate, and the environment is not polluted, so that the 2-bromopentane has high yield and high purity. The separated pyridine hydrochloride and the separated para-toluenesulfonic acid pyridine salt can meet the sales standard through simple and convenient purification treatment, and are convenient to sell or recycle, so that the full utilization of resources is realized.
In some embodiments, 2-pentanol, p-toluenesulfonyl chloride and pyridine are reacted in a first solvent, synthesized and isolated to obtain pentan-2-yl 4-methylbenzenesulfonate, further comprising the steps of:
step S11, sequentially dissolving p-toluenesulfonyl chloride and pyridine in a first solvent to obtain a first raw material system.
And step S12, adding 2-amyl alcohol into the first raw material system, and reacting for a first reaction time at a first reaction temperature to obtain a first product system.
And S13, filtering the first product system, and separating to obtain a first organic phase containing pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrochloride.
And step S14, desolventizing the first organic phase to obtain pentane-2-yl 4-methylbenzenesulfonate.
Step S11 may be implemented by:
And respectively adding the p-toluenesulfonyl chloride and the first solvent into a reactor, uniformly stirring at room temperature until the p-toluenesulfonyl chloride is completely dissolved, then continuously adding pyridine into the reaction vessel, and uniformly stirring at room temperature to obtain a first raw material system.
Wherein, the room temperature related by the embodiment of the invention can be any temperature between 15 ℃ and 30 ℃,
In some examples, the first solvent is a polar non-alcoholic solvent, for example, including but not limited to: one or more of dichloromethane, propionitrile, n-valeronitrile, isobutyronitrile, toluene and xylene.
Non-alcoholic solvents are selected as the first solvent to avoid the reaction of alcoholic solvents with p-toluenesulfonyl chloride to produce undesirable byproducts.
In some examples, the mass ratio of the first solvent to the p-toluenesulfonyl chloride is 1-5:1, e.g., 3-5:1, including but not limited to: 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc., such that the first feedstock system has a suitable reaction concentration.
In some embodiments, 2-pentanol, p-toluenesulfonyl chloride, and pyridine are reacted in a first solvent under dry anhydrous conditions.
That is, the reaction of 2-pentanol, p-toluenesulfonyl chloride and pyridine is carried out with the need to ensure that the reactor is dry and anhydrous, thereby reducing the occurrence of side reactions.
Step S12 may be implemented by:
2-amyl alcohol is added to the first raw material system in the reactor, for example, 2-amyl alcohol is added in a dropwise manner, so that the reaction process is stable and controllable.
In the process of dropwise adding 2-amyl alcohol into a first raw material system in a reactor, the temperature in the reactor is always kept to be a first reaction temperature, and then the first reaction time is reacted at the first reaction temperature, so that a first product system is obtained.
Further, before 2-pentanol is added dropwise into the reactor, the temperature of the first raw material system is controlled to be 0 ℃ -10 ℃ (i.e., the reaction vessel is cooled to 0 ℃ -10 ℃), and then 2-pentanol is added dropwise into the first raw material system. Through the cooling operation, the temperature of the reaction system is ensured to be less than or equal to 15 ℃, and the overtemperature of the reaction system caused by too fast reaction heat release in the dripping process is avoided.
In some examples, the first reaction temperature is from 10 ℃ to 15 ℃, for example, including but not limited to 10 ℃, 11 ℃, 12 ℃, 13 ℃, 14 ℃,15 ℃, and the like.
At the first reaction temperature, the reaction of 2-amyl alcohol, p-toluenesulfonyl chloride and pyridine can be ensured to be smoothly carried out and is always stable and controllable.
In some examples, the first reaction time is 3-4 days, that is, after the 2-pentanol is added dropwise, the internal temperature of the reactor is controlled to 10-15 ℃ and the reaction is kept at a temperature for 3-4 days to ensure that the reaction is sufficiently complete.
The chemical equation for the reaction of 2-pentanol, p-toluenesulfonyl chloride and pyridine is shown below:
From the above equation, there is a clear precipitation of pyridine hydrochloride during the reaction. In some embodiments, the end of the reaction is determined by detecting whether 2-pentanol is still remaining in the first product system by gas chromatography (Gas Chromatography, GC) and the reaction is ended when no 2-pentanol is detected remaining.
In some examples, the molar ratio of 2-pentanol to p-toluenesulfonyl chloride is 1 (1-1.1); the molar ratio of 2-amyl alcohol to pyridine is 1 (1-1.2); further, the molar ratio of 2-amyl alcohol, p-toluenesulfonyl chloride and pyridine is more preferably (1-1.1): (1-1.05): (1-1.1), so that the generation of side reaction products can be effectively avoided on the premise of ensuring that 2-amyl alcohol is fully and thoroughly reacted.
Step S13 may be implemented by:
The first product system is filtered and separated to obtain a first organic phase containing pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrochloride.
The first product system is filtered at 10-15 ℃ to obtain a first organic phase containing the target intermediate (pentane-2-yl 4-methylbenzenesulfonate) and a filter cake (pyridine hydrochloride).
In some embodiments, the filter cake is rinsed with a first solvent, the rinsed rinse is combined with the first organic phase for subsequent desolventizing treatment while also precipitating a pyridine hydrochloride filter cake that, after purification treatment, can meet sales criteria, either as a by-product for export, or for continued recycling.
In some embodiments, the mass ratio of the first solvent to 2-pentanol used to flush the filter cake is (1-2): 1, and a small number of flushes may be used to obtain a better flushing effect.
Step S14 may be implemented by:
the organic phase is desolventized under the conditions of 10 ℃ to 15 ℃ and vacuum degree of-0.03 MPa to 0.05MPa to obtain pentane-2-yl 4-methylbenzenesulfonate, and simultaneously, the first solvent is completely removed and collected.
In some embodiments, the stripped first solvent is subjected to a rectification process to achieve a purity level sufficient for recycling.
In some embodiments, the reaction of the pentan-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, the synthesis and isolation of 2-bromopentane, comprises the steps of:
and S21, dissolving pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent to obtain a second raw material system.
And S22, reacting the second raw material system for a second reaction time at a second reaction temperature to obtain a second product system.
And S23, adding water into the second product system, stirring, standing for layering, and separating to obtain a second organic phase containing 2-bromopentane and an aqueous phase containing pyridine p-toluenesulfonate.
And step S24, rectifying the second organic phase to obtain 2-bromopentane.
Step S21 may be implemented by:
And sequentially adding pentane-2-yl 4-methylbenzenesulfonate, pyridine hydrobromide and a second solvent into another clean reaction container, and slowly stirring to be uniform to obtain a second raw material system.
In the embodiment of the invention, the pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide are reacted in a second solvent in a weak base environment, so that the isomerization of 2-bromopentane to 3-bromopentane is basically inhibited.
In some embodiments, the weakly basic environment is maintained by adding pyridine to the reaction system, that is, by further adding pyridine to the reaction vessel.
In some embodiments, the second solvent is a polar water-soluble solvent including, but not limited to, one or more of methanol, ethanol, propanol, isopropanol, n-butanol.
The polar water-soluble solvent is selected as the second solvent to ensure that the pentane-2-yl 4-methylbenzenesulfonate and the pyridine hydrobromide can be dissolved in the second solvent and fully react, and simultaneously, the separation of the water-insoluble product and the water-soluble byproducts is facilitated.
In some embodiments, the molar ratio of pyridine hydrobromide to 2-pentanol is (1-1.2): 1, further (1-1.1): 1; the mass ratio of the second solvent to the pyridine hydrobromide is (1-5): 1, further (2-4): 1.
If pyridine is used to maintain a weakly basic environment, the molar ratio of pyridine to 2-pentanol is (0-0.1): 1, further (0.05-0.10): 1. Thus, on the premise of ensuring that pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide are fully and thoroughly reacted, the generation of side reaction products can be effectively avoided.
Step S22 may be implemented by:
the reactor is heated to a second reaction temperature (for example, slowly heated) so that the pyridine hydrobromide is gradually dissolved and completely dissolved, and the temperature of the reactor is controlled at the second reaction temperature for a second reaction time so that the pentane-2-yl 4-methylbenzenesulfonate and the pyridine hydrobromide are fully and thoroughly reacted.
In some examples, the second reaction temperature is 55 ℃ to 65 ℃, e.g., including, but not limited to, 55 ℃, 56 ℃, 57 ℃, 58 ℃, 59 ℃, 60 ℃, 61 ℃, 62 ℃, 63 ℃, 64 ℃, 65 ℃, and the like.
At the second reaction temperature, the reaction of pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide can be ensured to be carried out smoothly and always stably and controllably.
In some examples, the second reaction time is 24 hours to 36 hours, thereby ensuring the reaction is complete.
In some embodiments, the end of the reaction is determined by high performance liquid chromatography (High Performance Liquid Chromatography, HPLC) to determine if there is still any pentan-2-yl 4-methylbenzenesulfonate remaining in the second product system, and the reaction is terminated after the detection of no pentan-2-yl 4-methylbenzenesulfonate remaining.
The chemical reaction equation of pentane-2-yl 4-methylbenzenesulfonate with pyridine hydrobromide is shown below:
step S23 may be implemented by:
And (3) reducing the temperature of the reactor to 25-35 ℃, adding pure water into the reactor, fully stirring for a certain time, standing for a certain time (for example, fully stirring for 1h, standing for 1 h), and layering to obtain a second organic phase containing the target product 2-bromopentane and an aqueous phase containing pyridine p-toluenesulfonate, wherein the second solvent is also present in the aqueous phase.
In some embodiments, the aqueous phase containing the second solvent, pyridinium p-toluenesulfonate, is concentrated and purified to obtain a pyridinium toluenesulfonate product that meets sales standards, either for sale or for recycling. Meanwhile, the water after concentration and recovery can be reused.
The water used in step S23 may be pure water, and the mass ratio of water to pyridine hydrobromide is 1 to 2:1, for example, 1:1, 1.2:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1, 2:1, etc.
The water content is within the above range, a good concentration effect can be obtained, and the cost of concentration and crystallization does not increase greatly.
For step S24, rectifying the second organic phase to obtain the product 2-bromopentane with expected purity.
Based on the synthesis method provided by the embodiment of the invention, the purity of the 2-bromopentane after rectification treatment is more than or equal to 95%, and the effective conversion rate of the 2-bromopentane is more than 90%.
In summary, the synthesis method of 2-bromopentane provided by the embodiment of the invention has at least the following advantages:
First, by allowing the synthesis of 2-bromopentane to proceed in a neutral to weakly basic environment at all times, isomerization of 2-bromopentane to 3-bromopentane is effectively suppressed.
Secondly, the by-product pyridine hydrochloride and the para-toluenesulfonic acid pyridine salt generated in the reaction process are easy to separate, and the environment is not polluted, so that the 2-bromopentane has high yield and high purity. The separated pyridine hydrochloride and the separated para-toluenesulfonic acid pyridine salt can meet the sales standard through simple and convenient purification treatment, and are convenient to sell or recycle, so that the full utilization of resources is realized.
Thirdly, the used raw materials are low in price and easy to obtain, the solvent can be recycled in the reaction process, and three wastes are not generated basically, so that the synthesis cost of 2-bromopentane is reduced, and the method is more environment-friendly, and the synthesis method of 2-bromopentane provided by the embodiment of the invention is suitable for large-scale and continuous production.
Preferred embodiments of the present invention will be described in more detail below. While the preferred embodiments of the present invention are described below, it should be understood that the present invention may be embodied in various forms and should not be limited to the embodiments set forth herein. The specific techniques or conditions are not identified in the examples and are performed according to techniques or conditions described in the literature in this field or according to the product specifications. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention. In the examples below, "%" refers to weight percent, unless explicitly stated otherwise.
Example 1
This example 1 provides a synthetic method of 2-bromopentane, the preparation scheme is as follows:
572.97g of dichloromethane and 190.99g of p-toluenesulfonyl chloride are respectively added into a three-port reaction bottle with 1000mL, uniformly stirred at room temperature until the p-toluenesulfonyl chloride is completely dissolved, then 82.86g of pyridine is added into the reaction bottle, and uniformly stirred at room temperature, thus obtaining a first raw material system.
The temperature of the reactor is reduced to 5 ℃, 88.15g of 2-amyl alcohol is slowly dripped into a reaction bottle, the internal temperature of the reaction bottle is controlled between 10 ℃ and 15 ℃ in the dripping process, the internal temperature of the reaction bottle is kept between 13 ℃ and 15 ℃ after the dripping is finished, the temperature is kept for 3 days, no residue of 2-amyl alcohol is detected by GC, and the reaction is finished, thus obtaining a first product system.
The first product system was subjected to filtration to separate out the precipitated pyridine hydrochloride cake, the pyridine hydrochloride cake was washed with 88.15g of fresh methylene chloride, and simultaneously filtered to obtain a washing liquid, and the washing liquid and the filtrate were combined to obtain 884.44g of a first organic phase. At the same time 138.18g of pyridine hydrochloride wet cake were obtained.
The combined first organic phases were completely stripped of dichloromethane solvent at 10℃and vacuum of-0.02 MPa to give 239.5g of the target intermediate pentan-2-yl 4-methylbenzenesulfonate.
239.5G of pentan-2-yl 4-methylbenzenesulfonate is added into a reactor, 168.01g of pyridine hydrobromide is added into the reactor at one time, and 336.02g of ethanol solution is added into the reactor, and the mixture is slowly stirred until the mixture is fully dissolved, so as to obtain a second raw material system.
The internal temperature of the reactor is controlled to be 60-65 ℃, the reaction is carried out for 30 hours under the heat preservation, and whether pentane-2-yl 4-methylbenzenesulfonate remains in the second reaction product system is detected by HPLC until no residue exists, and the reaction is finished.
The internal temperature of the reactor was lowered to 30 ℃, 160.01g of pure water was added to the reactor, stirred sufficiently for 1 hour, allowed to stand for 1 hour, then layered, and after separation, the organic phase was taken out to obtain 148.05g of a second organic phase containing the target product and 755.49g of an aqueous phase containing pyridine p-toluenesulfonate.
And rectifying the second organic phase to obtain 136.7g of high-purity 2-bromopentane product, wherein the purity of the rectified 2-bromopentane product is 95.1% through GC detection.
Example 2
This example 2 provides a synthetic method of 2-bromopentane, the preparation scheme of which is shown as follows:
572.97g of dichloromethane and 190.99g of p-toluenesulfonyl chloride are respectively added into a three-port reaction bottle with 1000mL, uniformly stirred at room temperature until the p-toluenesulfonyl chloride is completely dissolved, then 82.86g of pyridine is added into the reaction bottle, and uniformly stirred at room temperature, thus obtaining a first raw material system.
The temperature of the reactor is reduced to 10 ℃, 88.15g of 2-amyl alcohol is slowly dripped into a reaction bottle, the internal temperature of the reaction bottle is controlled to be between 10 and 15 ℃ in the dripping process, after the dripping is finished, the internal temperature of the reaction bottle is kept at 12 to 14 ℃, the temperature is kept for 4 days, no residue of 2-amyl alcohol is detected by GC, and the reaction is finished, thus obtaining a first product system.
The first product system was subjected to filtration to separate out the precipitated pyridine hydrochloride cake, the pyridine hydrochloride cake was washed with 88.15g of fresh methylene chloride, and simultaneously filtered to obtain a washing liquid, and the washing liquid and the filtrate were combined to obtain 884.44g of a first organic phase. At the same time 138.18g of pyridine hydrochloride wet cake were obtained.
The combined first organic phases were completely stripped of dichloromethane solvent at 15℃and 0.05MPa vacuum to give 239.5g of the target intermediate pentan-2-yl 4-methylbenzenesulfonate.
239.5G of pentan-2-yl 4-methylbenzenesulfonate and 4.41g of pyridine are added into a reactor, 168.01g of pyridine hydrobromide are added into the reactor at one time, and 336.02g of ethanol solution are added into the reactor and stirred slowly until the materials are fully dissolved, so that a second raw material system is obtained.
The internal temperature of the reactor is controlled to be 63-65 ℃, the reaction is carried out for 30 hours under the heat preservation, and whether pentane-2-yl 4-methylbenzenesulfonate remains in the second reaction product system is detected by HPLC until no residue exists, and the reaction is finished.
The internal temperature of the reactor was lowered to 25 ℃, 160.01g of pure water was added to the reactor, the mixture was stirred sufficiently for 1 hour, the mixture was allowed to stand for 1 hour, the layers were separated, and an organic phase was taken after separation, so as to obtain 147.89g of a second organic phase containing the objective product and 759.13g of an aqueous phase containing pyridine p-toluenesulfonate.
And rectifying the second organic phase to obtain 136.7g of high-purity 2-bromopentane product, wherein the purity of the rectified 2-bromopentane product is 99.5% through GC detection.
In embodiments of the present invention, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" refers to two or more, unless explicitly defined otherwise.
The foregoing description is only for the convenience of those skilled in the art to understand the technical solution of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The synthesis method of 2-bromopentane is characterized by comprising the following steps of:
2-amyl alcohol, p-toluenesulfonyl chloride and pyridine are reacted in a first solvent, and pentane-2-yl 4-methylbenzenesulfonate is synthesized and separated;
Reacting the pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, synthesizing and separating to obtain the 2-bromopentane.
2. The method for synthesizing 2-bromopentane according to claim 1, wherein the 2-pentanol, p-toluenesulfonyl chloride and pyridine are reacted in a first solvent to synthesize and isolate pentan-2-yl 4-methylbenzenesulfonate, comprising:
Sequentially dissolving the tosyl chloride and the pyridine in the first solvent to obtain a first raw material system;
adding the 2-amyl alcohol into the first raw material system, and reacting for a first reaction time at a first reaction temperature to obtain a first product system;
Filtering the first product system and separating to obtain a first organic phase containing the pentane-2-yl 4-methylbenzenesulfonate and pyridine hydrochloride;
Desolventizing the first organic phase to obtain the pentan-2-yl 4-methylbenzenesulfonate.
3. The method for synthesizing 2-bromopentane according to claim 2, wherein the 2-pentanol, the p-toluenesulfonyl chloride and the pyridine are reacted in the first solvent under dry anhydrous conditions.
4. The method for synthesizing 2-bromopentane according to claim 2, wherein the first reaction temperature is 10℃to 15 ℃.
5. The method for synthesizing 2-bromopentane according to claim 1, wherein the first solvent is a polar non-alcoholic solvent; and/or the number of the groups of groups,
The second solvent is a polar water-soluble solvent.
6. The method for synthesizing 2-bromopentane according to any one of claims 1 to 5, wherein the pentan-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide are reacted in a second solvent under a weak alkaline environment.
7. The method for synthesizing 2-bromopentane according to claim 6, wherein said weakly alkaline environment is maintained by adding pyridine to the reaction system.
8. The method for synthesizing 2-bromopentane according to claim 6, wherein said reacting said pentan-2-yl 4-methylbenzenesulfonate and pyridine hydrobromide in a second solvent, synthesizing and separating to obtain said 2-bromopentane comprises:
Dissolving the pentane-2-yl 4-methylbenzenesulfonate and the pyridine hydrobromide in the second solvent to obtain a second raw material system;
Reacting the second raw material system for a second reaction time at a second reaction temperature to obtain a second product system;
Adding water into the second product system, stirring, standing for layering, and separating to obtain a second organic phase containing the 2-bromopentane and a water phase containing pyridine p-toluenesulfonate;
And rectifying the second organic phase to obtain the 2-bromopentane.
9. The method for synthesizing 2-bromopentane according to claim 8, wherein the mass ratio of the water to the pyridine hydrobromide is 1-2:1.
10. The method for synthesizing 2-bromopentane according to claim 8, wherein the second reaction temperature is 55℃to 65 ℃.
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