A system and process for preparing tert-amyl alcohol from mixed C5 fractions as raw materials.

Abstract

This invention provides a system for preparing tert-amyl alcohol from mixed C5 fractions, comprising: a hydration reactor; a C5 removal tower with its inlet connected to the outlet of the hydration reactor; a solvent recovery tower with its inlet connected to the outlet of the C5 removal tower; a heavy phase removal tower with its inlet connected to the outlet of the solvent recovery tower; a phase separation tank with its inlet connected to the top outlet of the heavy phase removal tower; a water recovery tower with its inlet connected to the aqueous phase outlet of the phase separation tank; and a tert-amyl alcohol dehydration tower with its inlet connected to the oil phase outlet of the phase separation tank, wherein the tert-amyl alcohol dehydration tower includes a side stream for extracting high-purity tert-amyl alcohol product. This invention employs a continuous hydration process, which offers flexibility and, compared to intermittent hydration processes, provides more stable product quality. This process system produces tert-amyl alcohol with high purity, low impurity content, and low water content, and can be used for industrial continuous production.

Description

Technical Field

[0001] This invention belongs to the field of tert-amyl alcohol technology, specifically relating to a system and process for preparing tert-amyl alcohol from mixed C5 fractions. Background Technology

[0002] Tert-amyl alcohol is a basic organic chemical raw material used in the production of chemical products such as tert-amylbenzene, tert-amylanthraquinone, pinacolone, and tert-amyl peroxide; it is also a raw material for the synthesis of fragrances and colorants for color films; and it has wide applications in the preparation of plasticizers, antioxidants, non-ferrous metal flotation agents, and paint solvents.

[0003] Currently, the main industrial methods for producing tert-amyl alcohol are the acetone-acetylene process and the indirect hydration method for olefins. The acetylene-acetone process is a relatively traditional method for preparing tert-amyl alcohol. Using acetylene and acetone as raw materials, acetylene is first dissolved in liquid ammonia, then mixed with acetone and a catalyst, and fed into an acetylation reactor. The reaction solution is flash-evaporated to separate unreacted acetylene and ammonia, and then unreacted acetone is evaporated to obtain methylbutynol. Methylbutynol then enters a hydrogenation reactor to produce tert-amyl alcohol, which is then dehydrated and purified to obtain the tert-amyl alcohol product. This process has high raw material costs, a complex process flow, and generates industrial waste residue when using calcium carbide hydrolysis to produce acetylene, causing environmental pollution.

[0004] The indirect hydration process for olefins is currently the industrialized production process for tert-amyl alcohol in China. This method involves first absorbing olefins with sulfuric acid to form sulfate esters, which are then hydrolyzed, and finally purified to obtain a high-purity alcohol product. The advantages of the indirect hydration method are that it does not require high purity of the target olefin in the feedstock, making it applicable to feedstocks of almost any olefin purity, and it also has a relatively high conversion rate. The disadvantages include a complex process, low selectivity for tert-amyl alcohol, problems such as equipment corrosion and difficult waste acid treatment, high investment in the equipment, and the cumbersome operation due to its batch reactor nature.

[0005] With the further development and utilization of C5 resources, the process of producing tert-amyl alcohol by directly reacting isopentenylene with water has become a key development focus in recent years. In the presence of a catalyst, olefins react directly with water to produce alcohols without passing through ester intermediates. Compared with indirect hydration methods, this direct hydration method uses a solid acid catalyst, eliminates equipment corrosion problems, and can continuously produce high-purity tert-amyl alcohol.

[0006] Chinese patent CN110172013A relates to a process for the hydration of tert-amyl alcohol using a solvent-based catalytic distillation method based on C5 fraction. The process utilizes isopentenyl-rich C5 fraction and water as raw materials, and carries out the hydration reaction in a catalytic distillation column in the presence of the lipophilic and hydrophilic solvent ethylene glycol butyl ether, using a strongly acidic cation exchange resin as a catalyst, to obtain tert-amyl alcohol. Compared to a fixed-bed hydration process, this invention offers improved conversion rate and selectivity. However, it only addresses the catalytic distillation process for producing tert-amyl alcohol, without mentioning product separation, and the high water-to-olefin ratio increases energy consumption for subsequent product separation.

[0007] Chinese patent CN108017508A discloses a method for preparing tert-amyl alcohol by hydration of isopentenene. The method involves mixing an isopentenene component rich in 2-methyl-1-butene and 2-methyl-2-butene with water and acetone, and then introducing the mixture into a fixed-bed reactor containing a strongly acidic cation exchange resin catalyst for a hydration reaction to obtain tert-amyl alcohol. This invention only describes the fixed-bed hydration reaction and the selection of the organic solvent, without mentioning the separation of the product.

[0008] Chinese patent CN107879894A discloses a method for preparing tert-amyl alcohol. The method involves simultaneously mixing isopentene-rich materials, water, and a tetrabutylammonium bromide co-catalyst in a static mixer. The mixed material is then fed into a fixed-bed reactor containing a strongly acidic cation exchange resin for hydration. High-purity tert-amyl alcohol is obtained through distillation and rectification. This invention employs a solvent-free method with excess isopentene. Due to the presence of a large amount of isopentene, it undergoes polymerization under the action of the acidic resin catalyst, generating a large amount of heavy components. After separating the excess isopentene, the tert-amyl alcohol product is obtained from the bottom of the purification column. Because no heavy component removal treatment is performed, the tert-amyl alcohol product contains heavy components. Furthermore, this invention does not specify the water content of the final product.

[0009] Chinese patent CN111777490A discloses a method for producing tert-amyl alcohol from isopentenene, mainly addressing the problem of tert-amyl alcohol forming an azeotrope with water in existing technologies, making separation difficult. The reactants are isopentenene and excess water, with acetone as the solvent. This invention describes a relatively complete process flow for producing tert-amyl alcohol. However, this process flow only applies when the reactants are pure isopentenene. When the reactants are a mixture of C5 components containing isopentenene, the azeotropic reaction between the C5 components and acetone causes the remaining C5 components to carry away the solvent, resulting in a significant loss of acetone. Furthermore, the purity of the tert-amyl alcohol product obtained by this process is only greater than 95%, failing to reach the 99.5% purity required for the national standard premium grade. The invention also does not specify the water content of the final product.

[0010] As can be seen from the above-mentioned inventions for synthesizing tert-amyl alcohol, some existing direct hydration methods only describe the synthesis of tert-amyl alcohol without detailing the separation of reaction products or the final acquisition of the tert-amyl alcohol product. While some inventions describe a relatively complete process flow from reaction to separation, the purity of the obtained tert-amyl alcohol product cannot reach the national standard for superior grade (>99.5%) due to inadequate separation units. Furthermore, none of these inventions specify the water content of the product. Currently, there is no invention providing a complete process flow for producing tert-amyl alcohol from mixed C5 fractions as raw materials. Summary of the Invention

[0011] In view of this, the technical problem to be solved by the present invention is to provide a system and process for preparing tert-amyl alcohol from mixed C5 fractions as raw materials. The system provided by the present invention produces tert-amyl alcohol with high purity, low impurity content and low water content, and can be used for industrial continuous production.

[0012] This invention provides a system for preparing tert-amyl alcohol from a mixture of C5 fractions, comprising:

[0013] Hydration reactor;

[0014] A decarbonization tower with its inlet connected to the outlet of the hydration reactor;

[0015] A solvent recovery tower whose inlet is connected to the outlet of the decarbonization tower;

[0016] A deweighting tower whose inlet is connected to the outlet of the solvent recovery tower;

[0017] A phase separation tank whose inlet is connected to the top outlet of the deweight removal tower;

[0018] A water recovery tower with its inlet connected to the aqueous phase outlet of the phase separation tank;

[0019] A tert-amyl alcohol dehydration tower with its inlet connected to the oil phase outlet of the phase separation tank, the tert-amyl alcohol dehydration tower including a side stream for extracting high-purity tert-amyl alcohol product.

[0020] Preferably, the hydration reactor is two or more fixed-bed reactors connected in series; preferably, a cooling device is provided between adjacent fixed-bed reactors connected in series.

[0021] The system also includes a water washing tower, and the top of the C5 decarbonization tower is provided with a C5 component outlet, which is connected to the inlet of the water washing tower.

[0022] Preferably, the solvent recovery tower is provided with a circulating solvent outlet at the top;

[0023] Preferably, the bottom of the deweighting tower is provided with a reweight component outlet.

[0024] Preferably, the top of the water recovery tower is provided with an azeotrope outlet for tert-amyl alcohol and water, and the azeotrope outlet for tert-amyl alcohol and water is connected to the phase separation tank.

[0025] Preferably, the top of the tert-amyl alcohol dehydration tower is provided with an azeotrope of tert-amyl alcohol and water, and the azeotrope of tert-amyl alcohol and water is connected to the phase separation tank.

[0026] This invention also provides a process for preparing tert-amyl alcohol from mixed C5 fractions as raw materials, comprising the following steps:

[0027] A) The mixed C5 fraction, deionized water and circulating solvent are mixed and then fed into the hydration reactor. Under the action of the catalyst, the isopentenyl in the mixed C5 fraction reacts with water to produce tert-amyl alcohol.

[0028] B) The reaction product obtained in step A) enters the decarbonization tower 5 to obtain the bottom liquid of the decarbonization tower 5;

[0029] C) The bottom liquid of the decarbonization tower 5 enters the solvent recovery tower, and the bottom liquid of the solvent recovery tower enters the heavy removal tower;

[0030] D) Tertiary amyl alcohol and water collected from the top of the dehydration tower are separated into phases in a phase separation tank to obtain an aqueous phase and an oil phase. The aqueous phase enters the water recovery tower, and the oil phase enters the tertiary amyl alcohol dehydration tower, from which high-purity tertiary amyl alcohol product is collected by side stream.

[0031] Preferably, the mixed C5 fraction of the reaction raw materials is a C5 fraction rich in isopentenylene or a high-purity isopentenylene component; preferably, the isopentenylene content in the C5 fraction rich in isopentenylene is 10-100 wt%, more preferably, the isopentenylene content is 30-100 wt%, wherein the isopentenylene is selected from one or more of 2-methyl-1-butene and 2-methyl-2-butene;

[0032] The circulating solvent is selected from one or more of acetone, isopropanol, and methyl ethyl ketone; preferably, the circulating solvent is isopropanol or acetone.

[0033] The catalyst is selected from one or more of strong acid cation exchange resins, solid phosphoric acid, and aluminum silicate catalysts; preferably, the catalyst is a strong acid cation exchange resin catalyst.

[0034] Preferably, the hydration reactor is two or more fixed-bed reactors connected in series, and the operating conditions are: temperature 40-80℃, pressure 0.4-2.0 MPaG, and space velocity 0.3-2.0 h⁻¹. -1 The molar ratio of water to isopentene is 1-10:1, and the mass ratio of circulating solvent to water is 3-15:1. Preferably, the operating conditions of the fixed-bed reactor are: temperature 50-70℃, pressure 0.4-1.0 MPaG, and space velocity 0.5-1.0 h⁻¹. -1The molar ratio of water to isopentenene is 3-5:1, and the mass ratio of circulating solvent to water is 3-5:1.

[0035] The operating conditions of the five-tower decarbonization system are: top temperature 20-60℃, bottom temperature 80-120℃, pressure 0-0.2 MPaG, and reflux ratio 1-6; preferably, the top temperature is 35-50℃, bottom temperature is 85-102℃, pressure is 0-0.1 MPaG, and reflux ratio is 1-2.

[0036] The remaining C5 component collected from the top of the C5 removal tower enters the water washing tower. After washing to remove the small amount of solvent carried in the remaining C5, the water exits the unit. The water containing solvent in the bottom of the tower is returned to the reaction feed line. The operating conditions of the water washing tower are: top temperature 35-50℃, bottom temperature 35-50℃, and pressure 0.2-0.5 MPaG.

[0037] The operating conditions of the solvent recovery tower are: top temperature 65-110℃, bottom temperature 85-125℃, pressure 0-0.2 MPaG, and reflux ratio 1-6; preferably, top temperature 75-85℃, bottom temperature 95-105℃, pressure 0-0.1 MPaG, and reflux ratio 1-3.

[0038] Preferably, the operating conditions of the deweight removal tower are: top temperature 80-102℃, bottom temperature 105-135℃, pressure 0-0.2 MPaG, and reflux ratio 0.5-4; more preferably, top temperature 85-102℃, bottom temperature 108-130℃, pressure 0-0.1 MPaG, and reflux ratio 0.5-2.

[0039] The operating conditions of the water recovery tower are: top temperature 80-102℃, bottom temperature 105-123℃, and pressure 0-0.1 MPaG; preferably, top temperature 85-92℃, bottom temperature 100-108℃, and pressure 0-0.03 MPaG.

[0040] The operating conditions of the tert-amyl alcohol dehydration tower are: top temperature 80-102℃, bottom temperature 105-123℃, and pressure 0-0.1 MPaG; preferably, the top temperature is 85-92℃, the bottom temperature is 99-110℃, and the pressure is 0-0.03 MPaG.

[0041] Preferably, the high-purity tert-amyl alcohol product has a water content of less than 300 ppm and a purity of more than 99.9%.

[0042] Compared with existing technologies, this invention provides a system for preparing tert-amyl alcohol from mixed C5 fractions as raw materials, comprising: a hydration reactor; a C5 removal tower with its inlet connected to the outlet of the hydration reactor; a solvent recovery tower with its inlet connected to the outlet of the C5 removal tower; a heavy phase removal tower with its inlet connected to the outlet of the solvent recovery tower; a phase separation tank with its inlet connected to the top outlet of the heavy phase removal tower; a water recovery tower with its inlet connected to the aqueous phase outlet of the phase separation tank; and a tert-amyl alcohol dehydration tower with its inlet connected to the oil phase outlet of the phase separation tank, wherein the tert-amyl alcohol dehydration tower includes a side stream for extracting high-purity tert-amyl alcohol product. This invention employs a continuous hydration process, which offers flexibility and more stable product quality compared to batch hydration processes. This process system produces tert-amyl alcohol with high purity, low impurity content, and low water content, and can be used for industrial continuous production. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the system for preparing tert-amyl alcohol from mixed C5 fractions provided by the present invention;

[0044] Figure 2 The gas chromatogram of the tert-amyl alcohol product obtained in Example 1. Detailed Implementation

[0045] This invention provides a system for preparing tert-amyl alcohol from a mixture of C5 fractions, comprising:

[0046] Hydration reactor;

[0047] A decarbonization tower with its inlet connected to the outlet of the hydration reactor;

[0048] A solvent recovery tower whose inlet is connected to the outlet of the decarbonization tower;

[0049] A deweighting tower whose inlet is connected to the outlet of the solvent recovery tower;

[0050] A phase separation tank whose inlet is connected to the top outlet of the deweight removal tower;

[0051] A water recovery tower with its inlet connected to the aqueous phase outlet of the phase separation tank;

[0052] A tert-amyl alcohol dehydration tower with its inlet connected to the oil phase outlet of the phase separation tank, the tert-amyl alcohol dehydration tower including a side stream for extracting high-purity tert-amyl alcohol product.

[0053] See Figure 1 , Figure 1 This is a schematic diagram of the system for preparing tert-amyl alcohol from mixed C5 fractions provided by the present invention.

[0054] The system for preparing tert-amyl alcohol provided by this invention includes a hydration reactor, wherein the hydration reactor is two or more fixed-bed reactors connected in series. In this invention, a cooling device is provided between adjacent fixed-bed reactors connected in series to improve the overall conversion rate of the reaction.

[0055] The hydration reactor includes a mixed feed inlet, which includes a mixed C5 fraction, deionized water, and a circulating solvent.

[0056] The system for preparing tert-amyl alcohol provided by the present invention further includes a decarbonization tower whose inlet is connected to the outlet of the hydration reactor.

[0057] In some specific embodiments of the present invention, the system further includes a water washing tower, and the top of the C5 decarbonization tower is provided with a C5 component outlet, which is connected to the inlet of the water washing tower.

[0058] The remaining C5 components collected from the top of the C5 removal tower enter the water washing tower. After the water wash removes the small amount of solvent carried in the remaining C5, the water exits the device, and the water containing solvent in the bottom of the tower is returned to the reaction feed pipeline.

[0059] The system for preparing tert-amyl alcohol provided by the present invention further includes a solvent recovery tower whose inlet is connected to the outlet of the decarbonylation tower; the top of the solvent recovery tower is provided with a circulating solvent outlet, and the circulating solvent collected from the top of the tower is returned to the reaction feed pipeline.

[0060] The system for preparing tert-amyl alcohol provided by the present invention further includes a heavy component removal column whose inlet is connected to the outlet of the solvent recovery column. The top of the heavy component removal column has an outlet for a mixture of tert-amyl alcohol and water. A heavy component outlet is located at the bottom of the heavy component removal column.

[0061] The inlet is connected to the top outlet of the de-weighting tower, and the phase separation tank is provided with an aqueous phase outlet and an oil phase outlet.

[0062] Furthermore, the system for preparing tert-amyl alcohol provided by the present invention also includes a water recovery tower whose inlet is connected to the aqueous phase outlet of the phase separation tank; the top of the water recovery tower is provided with an outlet for tert-amyl alcohol and water azeotrope, which is connected to the phase separation tank, and the outlet of the water recovery tower is connected to a water washing tower.

[0063] The system for preparing tert-amyl alcohol provided by the present invention further includes a tert-amyl alcohol dehydration tower whose inlet is connected to the oil phase outlet of the phase separation tank. The top of the tert-amyl alcohol dehydration tower is provided with an outlet for a tert-amyl alcohol and water azeotrope, which is connected to the phase separation tank. The tert-amyl alcohol dehydration tower includes a side stream for extracting high-purity tert-amyl alcohol product.

[0064] This invention also provides a process for preparing tert-amyl alcohol from mixed C5 fractions as raw materials, comprising the following steps:

[0065] A) The mixed C5 fraction, deionized water and circulating solvent are mixed and then fed into the hydration reactor. Under the action of the catalyst, the isopentenyl in the mixed C5 fraction reacts with water to produce tert-amyl alcohol.

[0066] B) The reaction product obtained in step A) enters the decarbonization tower 5 to obtain the bottom liquid of the decarbonization tower 5;

[0067] C) The bottom liquid of the decarbonization tower 5 enters the solvent recovery tower, and the bottom liquid of the solvent recovery tower enters the heavy removal tower;

[0068] D) Tertiary amyl alcohol and water collected from the top of the dehydration tower are separated into phases in a phase separation tank to obtain an aqueous phase and an oil phase. The aqueous phase enters the water recovery tower, and the oil phase enters the tertiary amyl alcohol dehydration tower, from which high-purity tertiary amyl alcohol product is collected by side stream.

[0069] The present invention first mixes a mixed C5 fraction, deionized water, and a recycled solvent, wherein the mixed C5 fraction is a C5 fraction rich in isopentenene or a high-purity isopentenene component; preferably, the isopentenene content in the C5 fraction rich in isopentenene is 10-100 wt%, more preferably, the isopentenene content is 30-100 wt%, wherein the isopentenene is selected from one or more of 2-methyl-1-butene and 2-methyl-2-butene;

[0070] The circulating solvent is selected from one or more of acetone, isopropanol, and methyl ethyl ketone; preferably, the circulating solvent is isopropanol or acetone.

[0071] The catalyst is selected from one or more of strong acid cation exchange resins, solid phosphoric acid, and aluminum silicate catalysts; preferably, the catalyst is a strong acid cation exchange resin catalyst.

[0072] The mixed raw materials are fed into a hydration reactor. In this invention, the hydration reactor is two or more fixed-bed reactors connected in series. The operating conditions are: temperature 40-80℃, pressure 0.4-2.0 MPaG, and space velocity 0.3-2.0 h⁻¹. -1 The molar ratio of water to isopentene is 1-10:1, and the mass ratio of circulating solvent to water is 3-15:1. Preferably, the operating conditions of the fixed-bed reactor are: temperature 50-70℃, pressure 0.4-1.0 MPaG, and space velocity 0.5-1.0 h⁻¹. -1 The molar ratio of water to isopentenene is 3-5:1, and the mass ratio of circulating solvent to water is 3-5:1.

[0073] The mixed C5 fraction is mixed with deionized water and circulating solvent and then fed into a fixed-bed reactor. Under the action of a catalyst, isopentenylene in the C5 fraction undergoes a hydration reaction with water to produce tert-amyl alcohol.

[0074] After hydration, the reaction products enter the C5 removal tower to obtain the tower bottom liquid. The remaining C5 components collected from the top of the C5 removal tower enter the water washing tower to remove the small amount of solvent carried in the remaining C5 before exiting the unit. The water washing water containing solvent in the tower bottom is returned to the reaction feed line.

[0075] The operating conditions of the five-tower decarbonization system are: top temperature 20-60℃, bottom temperature 80-120℃, pressure 0-0.2 MPaG, and reflux ratio 1-6; preferably, the top temperature is 35-50℃, bottom temperature is 85-102℃, pressure is 0-0.1 MPaG, and reflux ratio is 1-2.

[0076] The operating conditions of the water washing tower are: top temperature 35-50℃, bottom temperature 35-50℃, and pressure 0.2-0.5 MPaG. Preferably, the operating conditions of the water washing tower are: top temperature 40-45℃, bottom temperature 40-45℃, and pressure 0.3-0.4 MPaG.

[0077] The bottom liquid of the decarbonization tower enters the solvent recovery tower, and the circulating solvent collected from the top of the tower is returned to the reaction feed pipeline.

[0078] The operating conditions of the solvent recovery tower are: top temperature 65-110℃, bottom temperature 85-125℃, pressure 0-0.2 MPaG, and reflux ratio 1-6; preferably, top temperature 75-85℃, bottom temperature 95-105℃, pressure 0-0.1 MPaG, and reflux ratio 1-3.

[0079] The bottom liquid from the decarbonization column 5 enters the heavy weight removal column. The operating conditions of the heavy weight removal column are: top temperature 80-102℃, bottom temperature 105-135℃, pressure 0-0.2 MPaG, and reflux ratio 0.5-4; preferably, the top temperature is 85-102℃, bottom temperature is 108-130℃, pressure is 0-0.1 MPaG, and reflux ratio is 0.5-2.

[0080] The tert-amyl alcohol and water collected from the top of the dehydration tower are fed into a phase separation tank to separate into an aqueous phase and an oil phase. The aqueous phase is fed into a water recovery tower, while the oil phase is fed into a tert-amyl alcohol dehydration tower, from which a high-purity tert-amyl alcohol product is collected via a side stream.

[0081] The aqueous phase is an aqueous solution containing a small amount of tert-amyl alcohol, and the oil phase is a tert-amyl alcohol phase containing a small amount of water.

[0082] The operating conditions of the water recovery tower are: top temperature 80-102℃, bottom temperature 105-123℃, and pressure 0-0.1 MPaG; preferably, top temperature 85-92℃, bottom temperature 100-108℃, and pressure 0-0.03 MPaG.

[0083] The operating conditions of the tert-amyl alcohol dehydration tower are: top temperature 80-102℃, bottom temperature 105-123℃, and pressure 0-0.1 MPaG; preferably, the top temperature is 85-92℃, the bottom temperature is 99-110℃, and the pressure is 0-0.03 MPaG.

[0084] Ultimately, the obtained high-purity tert-amyl alcohol product had a water content of less than 300 ppm and a purity of more than 99.9%.

[0085] This invention uses a fixed-bed reactor to mix C5 fraction with deionized water and a circulating solvent. Under the action of a catalyst, isopentenylene in the C5 fraction undergoes a hydration reaction with water to produce tert-amyl alcohol. The reaction product enters a C5 removal tower. The remaining C5 fraction collected from the top of the tower enters a water washing tower to remove trace amounts of solvent carried in the remaining C5 fraction before exiting the unit. The water containing solvent in the bottom of the tower is returned to the reaction feed line. The bottom liquid of the C5 removal tower enters a solvent recovery tower. The circulating solvent collected from the top of the solvent recovery tower is returned to the reaction feed line, and the bottom liquid enters a heavy phase removal tower. The tert-amyl alcohol and water collected from the top of the heavy phase removal tower enter a phase separation tank for phase separation. The aqueous phase is an aqueous solution containing a small amount of tert-amyl alcohol, and the oil phase is a tert-amyl alcohol phase containing a small amount of water. The aqueous phase enters a water recovery tower. The tert-amyl alcohol and water azeotrope collected from the top of the water recovery tower is returned to the phase separation tank. The bottom liquid is water, which is sent to a water washing tower to wash the remaining C5 fraction. The oil phase enters the tert-amyl alcohol dehydration tower. The tert-amyl alcohol and water azeotrope collected from the top of the tower is returned to the phase separation tank, while a side stream yields high-purity tert-amyl alcohol product. This invention employs a flexible continuous hydration process, offering more stable product quality compared to batch hydration processes. The use of solid acid instead of traditional protic acid avoids catalyst corrosion of reaction equipment and the difficulty in treating waste acid. This process produces tert-amyl alcohol with high purity, low impurity content, and low water content, making it suitable for continuous industrial production.

[0086] The beneficial effects of this invention are:

[0087] (1) The continuous production process is adopted, and the water recovered by the water recovery tower and the solvent in the solvent removal tower can be recycled and reused. The operation is simple and saves raw material costs.

[0088] (2) Solid acid catalysts are used, the equipment is non-corrosive, and there is no need to replace the equipment regularly or add protective measures, resulting in low investment.

[0089] (3) The direct hydration reaction has high selectivity and low raw material consumption per unit product.

[0090] (4) The process technology is environmentally friendly, with no wastewater or waste acid discharge; the reaction temperature is below 70℃, and the safety factor is high.

[0091] (5) Continuous production process results in high product purity, low water content, and stable product quality.

[0092] To further understand the present invention, the system and process for preparing tert-amyl alcohol from mixed C5 fractions are described below with reference to embodiments. The scope of protection of the present invention is not limited by the following embodiments.

[0093] Example 1

[0094] This embodiment provides a system for preparing tert-amyl alcohol from a mixture of C5 fractions as raw materials, including:

[0095] Hydration reactor;

[0096] A decarbonization tower with its inlet connected to the outlet of the hydration reactor;

[0097] A solvent recovery tower whose inlet is connected to the outlet of the decarbonization tower;

[0098] A deweighting tower whose inlet is connected to the outlet of the solvent recovery tower;

[0099] A phase separation tank whose inlet is connected to the top outlet of the deweight removal tower;

[0100] A water recovery tower with its inlet connected to the aqueous phase outlet of the phase separation tank;

[0101] A tert-amyl alcohol dehydration tower with its inlet connected to the oil phase outlet of the phase separation tank, the tert-amyl alcohol dehydration tower including a side stream for extracting high-purity tert-amyl alcohol product.

[0102] The hydration reactor consists of two fixed-bed reactors connected in series. In this invention, a cooling device is provided between the adjacent fixed-bed reactors connected in series.

[0103] The hydration reactor includes a mixing feed inlet.

[0104] The system also includes a water washing tower, and the top of the C5 decarbonization tower is provided with a C5 component outlet, which is connected to the inlet of the water washing tower.

[0105] The remaining C5 components collected from the top of the C5 removal tower enter the water washing tower. After the water wash removes the small amount of solvent carried in the remaining C5, the water exits the device, and the water containing solvent in the bottom of the tower is returned to the reaction feed pipeline.

[0106] The solvent recovery tower is equipped with a circulating solvent outlet at the top, and the circulating solvent collected at the top of the tower is returned to the reaction feed pipeline.

[0107] The top of the heavy component removal tower has an outlet for a mixture of tert-amyl alcohol and water. The bottom of the heavy component removal tower has an outlet for the heavy component.

[0108] The phase separation tank is equipped with an aqueous phase outlet and an oil phase outlet.

[0109] The water recovery tower has an outlet for tert-amyl alcohol and water azeotrope at its top, which is connected to the phase separation tank. The outlet of the water recovery tower is connected to the water washing tower.

[0110] The top of the tert-amyl alcohol dehydration tower is provided with an outlet for tert-amyl alcohol and water azeotrope, which is connected to the phase separation tank. The tert-amyl alcohol dehydration tower includes a side stream for extracting high-purity tert-amyl alcohol product.

[0111] Preparation Example 1

[0112] Tert-amyl alcohol was produced using the system shown in Example 1. The feedstock was C5 fraction with an isopentenyl content of 30% wt; the solvent was isopropanol; and the catalyst was a strongly acidic cation exchange resin. The operating conditions of the hydration reactor were: reaction temperature 60°C, reaction pressure 0.4 MPaG, and space velocity 1 h⁻¹. -1 The water-to-olefin molar ratio is 5:1, and the solvent-to-water mass ratio is 4:1. The operating conditions for the five decarbonization towers are: top temperature 42℃, bottom temperature 87℃, pressure 0.01 MPaG, and reflux ratio 1:1. The operating conditions for the water washing towers are: top temperature 40℃, pressure 0.3 MPaG. The operating conditions for the solvent recovery towers are: top temperature 81℃, bottom temperature 100℃, pressure 0.01 MPaG, and reflux ratio 2:1. The heavy metal removal tower operation... Operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 110℃, pressure is 0.01 MPaG, and reflux ratio is 0.5:1; Water recovery column operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 102℃, and pressure is 0.01 MPaG; Tertiary amyl alcohol dehydration column operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 105℃, and pressure is 0.01 MPaG; Tertiary amyl alcohol product is collected from the lower side stream of the tertiary amyl alcohol dehydration column.

[0113] See Figure 2 , Figure 2 The gas chromatogram of the tert-amyl alcohol product obtained in Example 1.

[0114] Analysis showed that the conversion rate of isopentene was 60%, and the selectivity of tert-amyl alcohol was 95%. The product, tert-amyl alcohol, had a water content of 80 ppm and a purity greater than 99.9%.

[0115] Preparation Example 2

[0116] Tert-amyl alcohol was produced using the system shown in Example 1. The feedstock was C5 fraction with an isopentenyl content of 30% wt; the solvent was isopropanol; and the catalyst was a strongly acidic cation exchange resin. The operating conditions of the hydration reactor were: reaction temperature 60°C, reaction pressure 0.4 MPaG, and space velocity 1 h⁻¹. -1The water-to-olefin molar ratio is 3:1, and the solvent-to-water mass ratio is 4:1. The operating conditions for the five decarbonization towers are: top temperature 42℃, bottom temperature 87℃, pressure 0.01 MPaG, and reflux ratio 1:1. The operating conditions for the water washing towers are: top temperature 40℃, pressure 0.3 MPaG. The operating conditions for the solvent recovery towers are: top temperature 81℃, bottom temperature 100℃, pressure 0.01 MPaG, and reflux ratio 2:1. The heavy metal removal tower operation... Operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 110℃, pressure is 0.01 MPaG, and reflux ratio is 0.5:1; Water recovery column operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 102℃, and pressure is 0.01 MPaG; Tertiary amyl alcohol dehydration column operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 105℃, and pressure is 0.01 MPaG; Tertiary amyl alcohol product is collected from the lower side stream of the tertiary amyl alcohol dehydration column.

[0117] Analysis showed that the conversion rate of isopentene was 57%, and the selectivity of tert-amyl alcohol was 95%. The product, tert-amyl alcohol, had a water content of 90 ppm and a purity greater than 99.9%.

[0118] Preparation Example 3

[0119] tert-amyl alcohol was produced using the system shown in Example 1. The raw material was pure isopentenene, the solvent was isopropanol, and the catalyst was a strongly acidic cation exchange resin. The operating conditions of the hydration reactor were: reaction temperature 60°C, reaction pressure 0.4 MPaG, and space velocity 1 h⁻¹. -1 The water-to-olefin molar ratio is 3:1, and the solvent-to-water mass ratio is 4:1. The operating conditions for the five decarbonization towers are: top temperature 42℃, bottom temperature 87℃, pressure 0.01 MPaG, and reflux ratio 1:1. The operating conditions for the water washing towers are: top temperature 40℃, pressure 0.3 MPaG. The operating conditions for the solvent recovery towers are: top temperature 81℃, bottom temperature 100℃, pressure 0.01 MPaG, and reflux ratio 2:1. The heavy metal removal tower operation... Operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 110℃, pressure is 0.01 MPaG, and reflux ratio is 0.5:1; Water recovery column operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 102℃, and pressure is 0.01 MPaG; Tertiary amyl alcohol dehydration column operating conditions: Top temperature of the column is 87℃, bottom temperature of the column is 105℃, and pressure is 0.01 MPaG; Tertiary amyl alcohol product is collected from the lower side stream of the tertiary amyl alcohol dehydration column.

[0120] Analysis showed that the conversion rate of isopentene was 69%, and the selectivity of tert-amyl alcohol was 95%. The product, tert-amyl alcohol, had a water content of 80 ppm and a purity greater than 99.9%.

[0121] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A system for preparing tert-amyl alcohol from mixed C5 fractions, characterized in that, include: Hydration reactor; A decarbonization tower with its inlet connected to the outlet of the hydration reactor; A solvent recovery tower whose inlet is connected to the outlet of the decarbonization tower; A deweighting tower whose inlet is connected to the outlet of the solvent recovery tower; A phase separation tank whose inlet is connected to the top outlet of the deweight removal tower; A water recovery tower with its inlet connected to the aqueous phase outlet of the phase separation tank; A tert-amyl alcohol dehydration tower with its inlet connected to the oil phase outlet of the phase separation tank, the tert-amyl alcohol dehydration tower including a side stream for extracting high-purity tert-amyl alcohol product.

2. The system according to claim 1, characterized in that, The hydration reactor is two or more fixed-bed reactors connected in series; The system also includes a water washing tower, and the top of the C5 decarbonization tower is provided with a C5 component outlet, which is connected to the inlet of the water washing tower.

3. The system according to claim 1, characterized in that, Cooling devices are installed between adjacent fixed-bed reactors connected in series.

4. The system according to claim 1, characterized in that, The solvent recovery tower is equipped with a circulating solvent outlet at the top; The bottom of the deweighting tower is provided with a reweight component outlet.

5. The system according to claim 1, characterized in that, The water recovery tower is equipped with a tert-amyl alcohol and water azeotrope outlet at the top, which is connected to the phase separation tank.

6. The system according to claim 1, characterized in that, The top of the tert-amyl alcohol dehydration tower is provided with an azeotrope outlet for tert-amyl alcohol and water, which is connected to the phase separation tank.

7. A process for preparing tert-amyl alcohol from mixed C5 fractions as raw materials, characterized in that, Includes the following steps: A) The mixed C5 fraction, deionized water and circulating solvent are mixed and then fed into the hydration reactor. Under the action of the catalyst, the isopentenyl in the mixed C5 fraction reacts with water to produce tert-amyl alcohol. B) The reaction product obtained in step A) enters the decarbonization tower 5 to obtain the bottom liquid of the decarbonization tower 5; C) The bottom liquid of the decarbonization tower 5 enters the solvent recovery tower, and the bottom liquid of the solvent recovery tower enters the heavy removal tower; D) Tertiary amyl alcohol and water collected from the top of the dehydration tower are separated into phases in a phase separation tank to obtain an aqueous phase and an oil phase. The aqueous phase enters the water recovery tower, and the oil phase enters the tertiary amyl alcohol dehydration tower, from which high-purity tertiary amyl alcohol product is collected by side stream.

8. The process according to claim 7, characterized in that, The mixed C5 fraction is a C5 fraction rich in isopentenene or a high-purity isopentenene component; the isopentenene is selected from one or more of 2-methyl-1-butene and 2-methyl-2-butene; The circulating solvent is selected from one or more of acetone, isopropanol, and methyl ethyl ketone; The catalyst is selected from one or more of the following: strong acid cation exchange resin, solid phosphoric acid, and aluminum silicate catalyst.

9. The process according to claim 8, characterized in that, The isopentenyl content in the C5 fraction rich in isopentenyl is 10-100 wt%.

10. The process according to claim 8, characterized in that, The isopentenyl content in the C5 fraction rich in isopentenyl is 30-100 wt%.

11. The process according to claim 8, characterized in that, The circulating solvent is selected from isopropanol or acetone.

12. The process according to claim 8, characterized in that, The catalyst is a strong acid cation exchange resin catalyst.

13. The process according to claim 7, characterized in that, The hydration reactor is two or more fixed-bed reactors connected in series, and the operating conditions are: temperature 40-80℃, pressure 0.4-2.0 MPaG, and space velocity 0.3-2.0 h⁻¹. -1 The molar ratio of water to isopentenene is 1-10:1, and the mass ratio of circulating solvent to water is 3-15:

1. The operating conditions for the five decarbonization towers are: top temperature 20-60℃, bottom temperature 80-120℃, pressure 0-0.2 MPaG, and reflux ratio 1-6. The remaining C5 component collected from the top of the C5 removal tower enters the water washing tower. After washing to remove the small amount of solvent carried in the remaining C5, the water exits the unit. The water containing solvent in the bottom of the tower is returned to the reaction feed line. The operating conditions of the water washing tower are: top temperature 35-50℃, bottom temperature 35-50℃, and pressure 0.2-0.5 MPaG. The operating conditions of the solvent recovery tower are: top temperature 65-110℃, bottom temperature 85-125℃, pressure 0-0.2 MPaG, and reflux ratio 1-6.

14. The process according to claim 13, characterized in that, The operating conditions for the fixed-bed reactor are: temperature 50-70℃, pressure 0.4-1.0 MPaG, and space velocity 0.5-1.0 h⁻¹. -1 The molar ratio of water to isopentenene is 3-5:1, and the mass ratio of circulating solvent to water is 3-5:

1.

15. The process according to claim 13, characterized in that, The operating conditions of the five decarbonization towers are: top temperature 35-50℃, bottom temperature 85-102℃, pressure 0-0.1 MPaG, and reflux ratio 1-2.

16. The process according to claim 13, characterized in that, The operating conditions of the solvent recovery tower are: top temperature 75-85℃, bottom temperature 95-105℃, pressure 0-0.1 MPaG, and reflux ratio 1-3.

17. The process according to claim 7, characterized in that, The operating conditions for the deweight removal tower are: top temperature 80-102℃, bottom temperature 105-135℃, pressure 0-0.2 MPaG, and reflux ratio 0.5-4. The operating conditions of the water recovery tower are: top temperature 80-102℃, bottom temperature 105-123℃, and pressure 0-0.1 MPaG. The operating conditions of the tert-amyl alcohol dehydration tower are: top temperature 80-102℃, bottom temperature 105-123℃, and pressure 0-0.1 MPaG.

18. The process according to claim 17, characterized in that, The operating conditions for the deweight removal tower are: top temperature 85-102℃, bottom temperature 108-130℃, pressure 0-0.1 MPaG, and reflux ratio 0.5-2.

19. The process according to claim 17, characterized in that, The operating conditions of the water recovery tower are: top temperature 85-92℃, bottom temperature 100-108℃, and pressure 0-0.03 MPaG.

20. The process according to claim 17, characterized in that, The operating conditions of the tert-amyl alcohol dehydration tower are: top temperature 85-92℃, bottom temperature 99-110℃, and pressure 0-0.03 MPaG.

21. The process according to claim 7, characterized in that, The high-purity tert-amyl alcohol product has a water content of less than 300 ppm and a purity of more than 99.9%.

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