Processing technology for preparing isopentenol by isomerizing methyl butenol

Abstract

The invention discloses a processing technology for preparing isopentenol through isomerization of methyl butenol, and relates to the technical field of organic chemical preparation. The method at least comprises the following steps: S1, stirring a reactor, adding methyl butenol with a certain water content, a catalyst and a cocatalyst into the stirring reactor, and then heating under a stirring condition; s2, the dosage of the main catalyst and the dosage of the cocatalyst are determined, the wt% of the main catalyst in a reaction system is 0.5%-2.0%, and the wt% of the cocatalyst is 0.5%-2.0% of that of the main catalyst. According to the present invention, the water-containing methyl butenol is adopted as the raw material, the ammonium metavanadate is adopted as the catalyst, and the small amount of the nitrogen-containing compound is adopted as the ligand to perform the isomerization reaction to obtain the isopentenol 321, such that the new process is provided based on the deficiency of the early stage production process, the problem of the preparation of the isopentenol 321 through the isomerization of the methyl butenol is systematically solved, the continuous and stable production of the production device is ensured, and the production cost is reduced. The product yield is increased, the energy consumption is greatly reduced, and the wastewater discharge amount is greatly reduced.

Description

Technical Field

[0001] The invention relates to the technical field of organic chemical preparation, in particular to a processing technology for isomerizing methylbutenol to prepare isopentenol. Background Art

[0002] Isopentenol is an organic compound with the chemical formula C5H 10 O, a colorless transparent liquid, has two isomers 321 and 331, which can be converted into each other under appropriate conditions. Isopentenol 321 is an important raw material for synthetic fragrances, medicines and pesticide intermediates. Representative products include citral, isophytol, DV pyrethroids, vitamin A, vitamin E, etc. Isopentenol 331 is mainly used to synthesize the third generation of cement water reducers, namely the TPEG series of polycarboxylic acid water reducer raw materials.

[0003] At present, there are three main synthetic routes for isopentenol, depending on the reaction raw materials: the Prince method, the isoprene method, and the methylbutenol isomerization method. Each of the three synthetic routes has its own advantages and disadvantages, which mainly depends on the source of raw materials, downstream product applications, etc., and the main products obtained by different routes are different.

[0004] In the Prince process, isobutylene / formaldehyde generates isopentanol 331 as the main product under high temperature, high pressure and suitable catalyst (Wang Ju, Xu Jie, Wu Xianli, et al. Vapor-liquid equilibrium of two binary systems containing isopentanol under reduced pressure [J]. Journal of Chemical Engineering of Colleges and Universities, 2021, 35(02): 223-228.). If isopentanol 321 is required, isopentanol 331 needs to be further isomerized. Related processes or catalysts are disclosed in patents such as WO2008037693, CN103254036, and CN112430178A. The process has complex catalysts and requires high temperature and high pressure. The reaction conditions are very harsh, the equipment investment is large, and there are certain safety risks.

[0005] In the isoprene method, the product obtained by the direct hydration of isoprene is a mixture of isopentenol 321 and isopentenol 331 (Yang Zhi, Qiu Guisheng, Cheng Jianfang. Research on the Synthesis Process of Isopentenol [J]. Chemical Industry Journal, 2012, 26(06): 24-26+58.). Patent CN101070271 discloses a method for preparing isopentenol by hydrating isopentenol using solid proton acid as a catalyst. This method requires separation of the product, and then further isomerization of isopentenol 331 to obtain isopentenol. 321; isoprene / hydrochloric acid addition will produce two isomeric chlorides, and the product obtained after hydrolysis is a mixture of isopentanol 321 and 331 (Xia Meifang, Zhai Dewei, Huo Hongfei, et al. Preparation of isopentanol by efficient chlorination [J]. Zhejiang Chemical Industry, 2021, 52(03): 23-27+32.), and the production process is disclosed in patents such as CN102584519, CN107082740B, CN105175219B, and CN111187146B. However, the product of this process also needs to be separated and isomerized to obtain isopentanol 321, and it will bring a large amount of salt-containing wastewater.

[0006] From the existing literature survey, the literature reports of the synthesis of isopentenol by methylbutenol isomerization method are less, mainly a small amount of patent literature, such as patent CN102391073B discloses a production method of 2-methyl-3-butene-2-ol converted into isopentenol under the action of phosphoric acid, the conversion rate is only about 20%, the catalyst needs to be neutralized, the three wastes are generated in large amounts, etc. Patent CN101381283A provides a method for producing isopentenol from solvent-free 2-methyl-3-butene-2-ol under the action of baht, tungsten, and vanadium catalysts, which has high requirements for raw material moisture, high reaction temperature and pressure, and this type of catalyst is expensive. Patent CN107840781B discloses a method for converting 2-methyl-3-butene-2-ol into isopentenol with acidic ion exchange resin, the reaction has low per-pass conversion rate, and the resin is prone to aging. Patent US3925485 reacts under linalyl vanadate catalysis, and conversion rate is only 25.6%, selectivity 83%, and points out that this isomerization reaction needs to be carried out under anhydrous environment to avoid catalyst hydrolysis. In our early patent CN105967978, the methyl butenol containing 0.5%-6.5% water can effectively isomerize and synthesize isopentanol, but the catalyst ammonium metavanadate can be dissolved in a small amount in solutions such as hot water and alcohol, causing subsequent separation system to scale easily, affecting the continuous operation of production equipment, and the catalyst water resistance is still poor. In addition, methyl butenol, isopentanol 331, isopentanol 321 and water all have azeotropic phenomenon, causing subsequent separation process complexity, and cost is high. Based on the above-mentioned shortcomings, further optimize catalyst and improve production technology, intend to solve the difficult problem of existing methyl butenol isomerization and isopentanol. Summary of the invention

[0007] The purpose of the present invention is to provide a processing technology for isomerizing methyl butenol to prepare isopentenol, improve the catalytic system in the Chinese patent application number CN105967978, propose a reaction process, and intend to solve the technical problems raised in the background technology.

[0008] To achieve the above object, the present invention provides the following technical solution: a processing technology for isomerizing methylbutenol to prepare isopentenol, comprising at least the following steps:

[0009] S1: stirring reaction, adding methylbutenol with a certain water content, a catalyst and a co-catalyst into a stirring reactor, and then heating under stirring conditions;

[0010] S2: Determine the dosage of the main catalyst and the co-catalyst. The main catalyst is one or more compounds such as ammonium metavanadate, potassium metavanadate, sodium metavanadate, etc., preferably ammonium metavanadate; the co-catalyst is one or more alcoholamine compounds, such as methyl alcoholamine, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, etc., preferably diethanolamine. The main catalyst wt% in the reaction system is 0.5% to 2.0% (wt), and the co-catalyst is 0.5% to 2.0% (wt) of the main catalyst;

[0011] S3: The material from the stirred reactor undergoes secondary settling to remove the catalyst;

[0012] S4: sending the material after secondary sedimentation and catalyst removal to the scraper evaporator;

[0013] S5: The gaseous material from the scraper evaporator is sent to a coarse fractionation tower. The top of the coarse fractionation tower is partially condensed. The light component of the gas phase is sent to the tail gas incineration system. The liquid phase is sent to a membrane dehydration separator for dehydration. The dehydrated material is sent to a raw material recovery tower. The top material of the raw material recovery tower is sent back to the stirred reactor. The bottom material of the raw material recovery tower is isopentanol 331.

[0014] S6: The bottom material from the crude fraction tower is sent to the product tower for separation by atmospheric distillation. Isopentenol 321 is obtained at the top of the product tower, and the heavy component is obtained at the bottom of the product tower and sent to the incineration system as waste liquid.

[0015] Furthermore, the reaction temperature in S1 is 140° C. to 200° C., and the residence time is 100 minutes to 180 minutes.

[0016] Furthermore, the water content of the methyl butenol in S1 is 2% to 10%.

[0017] Furthermore, the secondary sedimentation and catalyst removal in S3 at least comprises the following steps:

[0018] The material from the stirred reactor is sent to the second settling tank after the first settling tank to remove the catalyst tank. In order to ensure the precipitation of the catalyst, the material stays in the first settling tank and the second settling tank for 5min to 10min;

[0019] The lower layer material with catalyst particles is re-sent into the stirred reactor through a centrifugal pump. In order to ensure the stability of the catalyst and co-catalyst in the system, the catalyst and co-catalyst are supplemented to the stirred reactor through the catalyst supplement tank and sent into the stirred reactor together with the circulating catalyst.

[0020] Furthermore, the residence time of the first settling tank for removing the catalyst is 5 minutes.

[0021] Furthermore, the S4 at least includes the following steps:

[0022] The material from the upper part of the second settling tank contains a small amount of soluble catalyst. The material from the upper part of the second settling tank will scale and clog the distillation tower during the subsequent separation process. The scraper evaporator is used to remove the soluble catalyst from the material from the upper part of the second settling tank.

[0023] Furthermore, the scraper evaporator has an evaporation temperature of 150°C to 180°C, and a liquid phase outlet temperature of 160°C to 180°C.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] 1. The present invention systematically solves the problem of isomerization of water-containing methylbutenol to prepare isopentenol 321, further increases the water content of methylbutenol to 10%, ensures continuous and stable production of the production device, and increases product yield;

[0026] 2. The present invention improves the catalyst system and enhances the water resistance of the catalyst;

[0027] 3. The present invention adopts sedimentation to remove catalyst, scraper evaporation to desalinate, and membrane separation to dehydrate, which ensures the stable operation of the production device, improves the reaction efficiency, and reduces the production energy consumption;

[0028] 4. The present invention adopts a scraper evaporator to remove the catalyst and inorganic salts in the process flow, which solves the scaling problem of subsequent equipment and ensures the continuous and stable operation of the process;

[0029] 5. The present invention utilizes membrane separation technology for dehydration, thereby solving the azeotropic problem of water, methylbutenol and isopentenol 331, and reducing production energy consumption;

[0030] 6. The present invention adopts supplementary catalyst and co-catalyst to ensure the stable operation of the reaction system. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0032] Figure 1 The present invention is a schematic flow chart of a novel process for preparing isopentenol by isomerization of methylbutenol.

[0033] 1. Stirred reactor; 2. First sedimentation tank; 3. Second sedimentation tank; 4. Scraper evaporator; 5. Coarse fractionation tower; 6. Product tower; 7. Membrane dehydration separator; 8. Raw material recovery tower; 9. Catalyst replenishing tank; 10. Centrifugal pump. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0035] See also Figure 1 , a processing technology for isomerizing methylbutenol to prepare isopentenol, the following embodiments are proposed:

[0036] Embodiment 1:

[0037] Methyl butenol, ammonium metavanadate and diethanolamine containing 2% water are added to the stirred reactor 1, so that the catalyst wt% in the reaction system is 1.5%, and the co-catalyst is 1% of the catalyst mass fraction, and an isomerization reaction is carried out in the stirred reactor 1, the reaction temperature is 150°C, and the residence time is 180 minutes. The material from the reactor is removed from the catalyst in the first settling tank 2, the residence time is 5 minutes, and then enters the second settling tank 3 to remove the catalyst, and the residence time is 8 minutes. The supernatant from the second settling tank 3 is sent to the scraper evaporator 4, and the catalyst and inorganic salt are removed in the scraper evaporator 4. The gas phase outlet temperature of the scraper evaporator 4 is 150°C to 160°C, and the liquid phase outlet temperature is 160°C to 170°C. The gas phase material of the scraper evaporator 4 is distilled at normal pressure in the coarse fractionation tower 5. The top of the coarse fractionation tower 5 adopts a semi-condenser, and the gas phase discharge is sent to the tail gas treatment system. The liquid phase discharge at the top of the coarse fractionation tower 5 is sent to the membrane dehydration separator 7. The dehydrated material is sent to the raw material recovery tower 8. In the raw material recovery tower 8, methyl butenol is extracted from the top of the raw material recovery tower 8, and the methyl butenol is sent back to the stirring reactor 1. The bottom of the raw material recovery tower 8 obtains isopentanol 331. The bottom material of the coarse fractionation tower 5 is sent to the product tower 6, and atmospheric distillation is adopted. In the product tower 6, the product, i.e., isopentanol 321, is extracted from the top of the product tower 6, and the bottom of the product tower 6 is a reboiler, which is sent to the incineration system. The purity of the isopentanol 321 product is wt 99.5%, and the product yield is wt 93.5% based on methyl butenol.

[0038] Embodiment 2:

[0039] Methyl butenol, ammonium metavanadate and diisopropanolamine containing 3% water are added to the stirred reactor 1, so that the catalyst wt% in the reaction system is 0.8%, and the promoter is 1.5% of the catalyst mass fraction, and an isomerization reaction is carried out in the stirred reactor 1, the reaction temperature is 160°C, and the residence time is 120 minutes. After the material from the stirred reactor 1 passes through the first settling tank 2 and the second settling tank 3, the supernatant is sent to the scraper evaporator 4, and the catalyst and inorganic salt are removed in the scraper evaporator 4, the scraper gas phase outlet temperature is 160°C to 170°C, and the liquid phase outlet temperature is 170°C to 180°C. The gas phase material of the scraper evaporator 4 is distilled at normal pressure in the coarse fractionation tower 5. The top of the coarse fractionation tower 5 adopts a semi-condenser, and the gas phase discharge is sent to the tail gas treatment system, and the liquid phase discharge is sent to the membrane dehydration separator 7. The dehydrated material is sent to the raw material recovery tower 8. In the raw material recovery tower 8, methyl butenol is extracted from the top of the raw material recovery tower 8, and the methyl butenol is sent back to the stirring reactor 1. The bottom of the raw material recovery tower 8 obtains isopentanol 331. The bottom material of the coarse fractionation tower 5 is sent to the product tower 6, and atmospheric distillation is adopted. In the product tower 6, the product, i.e., isopentanol 321, is extracted from the top of the product tower 6, and the bottom of the product tower 6 is a reboiler. The purity of the isopentanol 321 product is wt 99.5%, and the product yield is wt 90.1% based on methyl butenol.

[0040] Embodiment 3:

[0041] Methyl butenol, ammonium metavanadate and triisopropanolamine containing 5% water are added to the stirred reactor 1, so that the catalyst wt% in the reaction system is 2.0%, and the co-catalyst is 2% of the catalyst mass fraction, and an isomerization reaction is carried out in the stirred reactor 1, the reaction temperature is 170°C, and the residence time is 100 minutes. After the material from the stirred reactor 1 passes through the first settling tank 2 and the second settling tank 3, the supernatant is sent to the scraper evaporator 4, and the catalyst and inorganic salt are removed in the scraper evaporator 4, the scraper gas phase outlet temperature is 150°C to 160°C, and the liquid phase outlet temperature is 170°C to 180°C. The gas phase material of the scraper evaporator 4 is distilled at normal pressure in the coarse fractionation tower 5. The top of the coarse fractionation tower 5 adopts a semi-condenser, and the gas phase discharge is sent to the tail gas treatment system, and the liquid phase discharge is sent to the membrane dehydration separator 7. The dehydrated material is sent to the raw material recovery tower 8. In the raw material recovery tower 8, methyl butenol is extracted from the top of the raw material recovery tower 8, and the methyl butenol is sent back to the stirring reactor 1. The bottom of the raw material recovery tower 8 obtains isopentanol 331. The bottom material of the coarse fractionation tower 5 is sent to the product tower 6, and atmospheric distillation is adopted. In the product tower 6, the product, i.e., isopentanol 321, is extracted from the top of the product tower 6, and the bottom of the product tower 6 is a reboiler. The purity of the isopentanol 321 product is wt 99.5%, and the product yield is wt 88.3% based on methyl butenol.

[0042] Embodiment 4:

[0043] Methyl butenol, sodium metavanadate and triisopropanolamine containing 10% water are added to the stirred reactor 1, so that the catalyst wt% in the reaction system is 1.5%, and the co-catalyst is 1% of the catalyst mass fraction, and an isomerization reaction is carried out in the stirred reactor 1, the reaction temperature is 200°C, and the residence time is 120 minutes. After the material from the stirred reactor 1 passes through the first settling tank 2 and the second settling tank 3, the supernatant is sent to the scraper evaporator 4, and the catalyst and inorganic salt are removed in the scraper evaporator 4, the scraper gas phase outlet temperature is 155°C to 165°C, and the liquid phase outlet temperature is 165°C to 175°C. The gas phase material of the scraper evaporator 4 is distilled at normal pressure in the coarse fractionation tower 5. The top of the coarse fractionation tower 5 adopts a semi-condenser, and the gas phase discharge is sent to the tail gas treatment system, and the liquid phase discharge is sent to the membrane dehydration separator 7. The dehydrated material is sent to the raw material recovery tower 8. In the raw material recovery tower 8, methyl butenol is extracted from the top of the raw material recovery tower 8, and the methyl butenol is sent back to the stirring reactor 1. The bottom of the raw material recovery tower 8 obtains isopentanol 331. The bottom material of the coarse fractionation tower 5 is sent to the product tower 6, and atmospheric distillation is adopted. In the product tower 6, the product, i.e., isopentanol 321, is extracted from the top of the product tower 6, and the bottom of the product tower 6 is a reboiler. The purity of the isopentanol 321 product is wt 98.3%, and the product yield is wt 80.5% based on methyl butenol.

[0044] Embodiment 5:

[0045] Methyl butenol, potassium metavanadate and triisopropanolamine containing 8% water are added to the stirred reactor 1, so that the catalyst wt% in the reaction system is 2.0%, and the promoter is 0.5% of the catalyst mass fraction, and an isomerization reaction is carried out in the stirred reactor 1, the reaction temperature is 140°C, and the residence time is 180 minutes. After the material from the stirred reactor 1 passes through the first settling tank 2 and the second settling tank 3, the supernatant is sent to the scraper evaporator 4, and the catalyst and inorganic salt are removed in the scraper evaporator 4, the scraper gas phase outlet temperature is 160°C to 170°C, and the liquid phase outlet temperature is 170°C to 180°C. The gas phase material of the scraper evaporator 4 is distilled at normal pressure in the coarse fractionation tower 5. The top of the coarse fractionation tower 5 adopts a semi-condenser, the gas phase discharge is sent to the tail gas treatment system, the liquid phase discharge is sent to the membrane dehydration separator 7, and the dehydrated material is sent to the raw material recovery tower 8. In the raw material recovery tower 8, methyl butenol is extracted from the top of the raw material recovery tower 8, and the methyl butenol is sent back to the stirring reactor 1. The bottom of the raw material recovery tower 8 obtains isopentanol 331. The bottom material of the coarse fractionation tower 5 is sent to the product tower 6, and atmospheric distillation is adopted. In the product tower 6, the product, i.e., isopentanol 321, is extracted from the top of the product tower 6, and the bottom of the product tower 6 is a reboiler. The purity of the isopentanol 321 product is wt 99.0%, and the product yield is wt 75.7% based on methyl butenol.

[0046] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A process for isomerizing methylbutenol to prepare isopentenol, characterized in that: At least the following steps are included: S1: stirring the reaction, adding methylbutenol with a certain water content, a catalyst and a co-catalyst into a stirring reactor (1), and then heating the reactor under stirring conditions; S2: Determine the amount of the main catalyst and the co-catalyst, the main catalyst in the reaction system is 0.5% to 2.0% (wt), and the co-catalyst is 0.5% to 2.0% of the main catalyst; S3: the material from the stirred reactor (1) is subjected to secondary sedimentation to remove the catalyst; S4: sending the material after the secondary settling and removal of the catalyst into the plate evaporator (4); S5: The gaseous material from the scraper evaporator (4) is sent to the coarse fractionation tower (5), the top of the coarse fractionation tower (5) is partially condensed, the light component of the gas phase is sent to the tail gas incineration system, the liquid phase is sent to the membrane dehydration separator (7) for dehydration, and the dehydrated material is sent to the raw material recovery tower (8), the top material of the raw material recovery tower (8) is sent back to the stirred reactor (1), and the bottom material of the raw material recovery tower (8) is isopentanol 331; S6: The bottom material from the crude fraction tower (5) is sent to the product tower (6) and separated by atmospheric distillation. Isopentanol 321 is obtained at the top of the product tower (6), and the heavy component is obtained at the bottom of the product tower (6) and sent to the incineration system as waste liquid.

2. The process for preparing isopentenol by isomerization of methylbutenol according to claim 1, characterized in that: The reaction temperature in S1 is 140° C. to 200° C., and the residence time is 100 minutes to 180 minutes.

3. The process for preparing isopentenol by isomerization of methylbutenol according to claim 1, characterized in that: The water content of the methylbutenol in S1 is 2% to 10%.

4. The process for preparing isopentenol by isomerization of methylbutenol according to claim 1, characterized in that: The main catalyst in S2 includes at least one or more of ammonium metavanadate, potassium metavanadate and sodium metavanadate; the co-catalyst includes at least one or more of alcoholamine compounds, and the alcoholamine compounds include at least methylolamine, monoethanolamine, diethanolamine, triethanolamine, diisopropanolamine and triisopropanolamine.

5. The process for preparing isopentenol by isomerization of methylbutenol according to claim 1, characterized in that: The secondary sedimentation catalyst removal in S3 at least comprises the following steps: The material from the stirred reactor (1) is sent from the first settling tank (2) to the second settling tank (3) to remove the catalyst. In order to ensure the precipitation of the catalyst, the material stays in the first settling tank (2) and the second settling tank (3) for 5 minutes to 10 minutes; The lower layer material with catalyst particles is re-sent into the stirred reactor (1) through a centrifugal pump (10). In order to ensure the stability of the catalyst and the co-catalyst in the system, the catalyst and catalyst supplement configured in the catalyst supplement tank (9) are sent to the stirred reactor (1) together with the circulating catalyst.

6. The process for preparing isopentenol by isomerization of methylbutenol according to claim 4, characterized in that: The residence time of the first settling tank (2) for removing the catalyst is 5 minutes.

7. The process for preparing isopentenol by isomerization of methylbutenol according to claim 4, characterized in that: The S4 at least comprises the following steps: The material from the upper part of the second settling tank (3) contains a small amount of soluble catalyst. The material from the upper part of the second settling tank (3) will form scale and clog the distillation tower during the subsequent separation process. The scraper evaporator (4) is used to remove the material from the upper part of the second settling tank (3).

8. The process for preparing isopentenol by isomerization of methylbutenol according to claim 6, characterized in that: The scraper evaporator (4) has an evaporation temperature of 150°C to 180°C, and a liquid phase outlet temperature of 160°C to 180°C.

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