Method and device for recovering methanol and hydrolyzing undecylenic acid methyl ester

Abstract

The present application relates to a kind of methyleleostearate hydrolysis reaction and methanol recovery method, raw material methyleleostearate and water occur hydrolysis reaction under the condition of 190~215 ℃, 1.5~2.2 MPa, and methyleleostearate is generated eleostearic acid and methanol;10-methyleleostearate and water mass fraction ratio is 1:(0.5~4).Methyleleostearate hydrolysis preparation eleostearic acid, methyleleostearate hydrolysis reaction and reaction product methanol recovery coupling, recover methanol while hydrolysis reaction, promote the reaction to positive direction, shorten reaction time, improve methyleleostearate conversion rate and eleostearic acid yield, simultaneously obtain high concentration methanol solution, simplify process flow, reduce energy consumption, save production cost.

Description

Technical Field

[0001] This invention belongs to the field of long-chain nylon production technology, specifically relating to a method and apparatus for the hydrolysis reaction of undecenoic acid methyl ester and methanol recovery. Background Technology

[0002] Undecenoic acid (10-undecenoic acid), CAS No.: 112-38-9, Molecular formula: C 11 H 20 O2, molecular weight: 184.3, molecular formula:

[0003]

[0004] Undecenoic acid is an important raw material for the synthesis of fragrances, such as γ-undecyl lactone, polycyclopentadecanol, muscone, nonanal, and nonanol. It can also be used as a raw material for antibiotics and drugs for treating dermatophytes.

[0005] Undecenoic acid (UDA) is primarily derived from castor oil. Castor oil undergoes transesterification with methanol to produce methyl ricinoleate, which is then cracked to produce methyl undecenoate and heptanal. Methyl undecenoate is then saponified and acidified to obtain undecenoic acid. In this method, the preparation of undecenoic acid from methyl undecenoate using a saponification-acidification process involves large amounts of strong acids and bases such as sodium hydroxide and sulfuric acid, increasing the difficulty of wastewater treatment. Furthermore, the resulting solid salts can only be treated as hazardous waste, leading to resource waste and increased costs. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies by providing a method and apparatus for the hydrolysis reaction of undecenoic acid methyl ester and methanol recovery that improves the conversion rate of undecenoic acid methyl ester and the yield of undecenoic acid.

[0007] The purpose of this invention is to provide a method for the hydrolysis reaction of methyl undecenoate and the recovery of methanol. The raw material methyl undecenoate undergoes a hydrolysis reaction with water at 190-215°C and 1.5-2.2 MPa to produce undecenoic acid and methanol. The mass ratio of methyl undecenoate to water is 1:(0.5-4).

[0008] Furthermore, the mass concentration of the methanol is 90-99%.

[0009] Furthermore, the mass ratio of the raw material undecenoic acid methyl ester to water is 1:(1-3).

[0010] Furthermore, the raw material undecenoic acid methyl ester, water, and internally circulating water are continuously added to the hydrolysis reactor for hydrolysis reaction. The top gas phase outlet of the hydrolysis reactor is connected to the lower gas phase inlet of the methanol recovery tower, and the bottom liquid phase outlet of the methanol recovery tower is connected to the upper liquid phase inlet of the hydrolysis reactor.

[0011] Methanol vapor at the top of the methanol recovery tower is cooled by a cooler, and the cooled methanol water flows back into the methanol recovery tower. The methanol vapor that is not cooled by the cooler is condensed by a methanol water condenser to obtain a methanol-water solution. The hydrolysis reaction liquid discharged from the bottom of the hydrolysis reactor enters the hydrolysis flash tank. The top of the hydrolysis flash tank discharges methanol-containing water vapor, and the liquid at the bottom of the hydrolysis flash tank flows by gravity to the oil-water separator. In the oil-water separator, oil and water are separated. The oil phase is sent to subsequent processes for processing, and the aqueous phase is returned to the hydrolysis reactor after being pressurized by a water circulation pump.

[0012] Furthermore, the bottom temperature of the methanol recovery tower is 180–220°C and the top temperature is 140–170°C.

[0013] Furthermore, the oil-water separator operates at the same pressure as the hydrolysis flash tank.

[0014] An apparatus for the hydrolysis reaction and methanol recovery method of undecenoic acid methyl ester as described above is also provided, comprising a hydrolysis reactor, a methanol recovery tower, a methanol-water condenser, a hydrolysis flash tank, and an oil-water separator; the top gas phase outlet of the hydrolysis reactor is connected to the lower gas phase inlet of the methanol recovery tower, and the bottom liquid phase outlet of the methanol recovery tower is connected to the upper liquid phase inlet of the hydrolysis reactor; a cooler is provided at the top steam outlet of the methanol recovery tower, and the steam outlet of the cooler is connected to the steam inlet of the methanol-water condenser; the bottom liquid outlet of the hydrolysis reactor is connected to the liquid inlet of the hydrolysis flash tank, and the bottom liquid outlet of the hydrolysis flash tank is connected to the liquid inlet of the oil-water separator; the aqueous phase outlet of the oil-water separator is connected to the upper inlet of the hydrolysis reactor via a water circulation pump.

[0015] Furthermore, the lower gas phase inlet of the methanol recovery tower is higher than the bottom liquid phase outlet, and the bottom liquid phase outlet of the methanol recovery tower is higher than the upper liquid phase inlet of the hydrolysis reactor.

[0016] Furthermore, the hydrolysis flash tank is located above the oil-water separator.

[0017] Furthermore, the hydrolysis reactor is equipped with an internal heater and a stirrer, with the stirrer blades arranged below the horizontal center of the internal heater.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention uses the hydrolysis of undecenoic acid methyl ester to prepare undecenoic acid, and couples the hydrolysis reaction of undecenoic acid methyl ester with the recovery of methanol as a reaction product. Methanol is recovered at the same time as the hydrolysis reaction, which promotes the reaction in the forward direction, shortens the reaction time, improves the conversion rate of undecenoic acid methyl ester and the yield of undecenoic acid, and obtains a high concentration of methanol solution. This simplifies the process flow, reduces energy consumption, and saves production costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the process of the undecenoic acid methyl ester hydrolysis reaction and methanol recovery device of the present invention. Detailed Implementation

[0020] The apparatus and process of the present invention will be further described in detail below with reference to the accompanying drawings:

[0021] The hydrolysis of undecenoic acid methyl ester refers to the reaction of undecenoic acid methyl ester with water under certain temperature and pressure to produce undecenoic acid and methanol. The reaction equation is as follows:

[0022] C 12 H 22 O2 + H2O → C 11 H 20 O2+CH3OH

[0023] This reaction requires the continuous removal of methanol to proceed completely, therefore, both the hydrolysis reaction and methanol recovery need to be considered simultaneously.

[0024] This invention employs, as follows Figure 1The undecenoic acid methyl ester hydrolysis reaction and methanol recovery device shown includes a hydrolysis reactor 1, a methanol recovery tower 2, a methanol-water condenser 3, a hydrolysis flash tank 4, and an oil-water separator 5. The top gas phase outlet 1-1 of the hydrolysis reactor 1 is connected to the lower gas phase inlet 2-1 of the methanol recovery tower 2, and the bottom liquid phase outlet 2-2 of the methanol recovery tower 2 is connected to the upper liquid phase inlet 1-2 of the hydrolysis reactor 1. The lower gas phase inlet 2-1 of the methanol recovery tower 2 is higher than the bottom liquid phase outlet 2-2. Simultaneously, the methanol recovery tower 2 is positioned higher than the hydrolysis reactor 1, ensuring that the liquid in the bottom of the methanol recovery tower 2 can be normally returned to the hydrolysis reactor. In reactor 1, a cooler 2-3 is installed at the top steam outlet of methanol recovery tower 2. The steam outlet of cooler 2-3 is connected to the steam inlet of methanol water condenser 3. The bottom liquid outlet of hydrolysis reactor 1 is connected to the liquid inlet of hydrolysis flash tank 4. The bottom liquid outlet of hydrolysis flash tank 4 is connected to the liquid inlet of oil-water separator 5. The aqueous phase outlet of oil-water separator 5 is connected to the upper inlet of hydrolysis reactor 1 via water circulation pump 6. Hydrolysis flash tank 4 is located above oil-water separator 5, so that the liquid at the bottom of hydrolysis flash tank 4 flows by gravity into oil-water separator 5.

[0025] In this embodiment, the hydrolysis reactor 1 is equipped with an internal heater and a stirrer. The heater provides heat for the hydrolysis reaction, and the stirrer increases the mixing intensity of methyl undecenoate and water, which is beneficial to the hydrolysis reaction. The blades of the stirrer are arranged at a position slightly below the horizontal center of the internal heater of the hydrolysis reactor. The stirrer is arranged at this position to increase the flow velocity of the liquid in the heat exchange tube. The increased flow velocity in the tube can improve the heat transfer efficiency of the heat exchanger and reduce the heat exchange area.

[0026] The hydrolysis reaction of methyl undecenoate and the methanol recovery method are as follows:

[0027] The raw material undecenoic acid methyl ester, water, and internally circulated water are continuously added to the hydrolysis reactor 1 for hydrolysis reaction. The raw material undecenoic acid methyl ester and water undergo hydrolysis reaction under the conditions of 190-215℃ and 1.5-2.2MPa, and the mass ratio of undecenoic acid methyl ester to water is 1:(0.5-4), preferably 1:(1-3).

[0028] The top gas phase outlet 1-1 of the hydrolysis reactor 1 is connected to the lower gas phase inlet 2-1 of the methanol recovery tower 2, and the bottom liquid phase outlet 2-2 of the methanol recovery tower 2 is connected to the upper liquid phase inlet 1-2 of the hydrolysis reactor 1.

[0029] Methanol vapor at the top of methanol recovery tower 2 is cooled by cooler 2-3 to increase methanol concentration. The cooled methanol-water mixture flows back into methanol recovery tower 2. Methanol vapor that is not cooled by cooler 2-3 is condensed by methanol-water condenser 3 to obtain a high-concentration methanol-water solution. The hydrolysis reaction liquid discharged from the bottom of hydrolysis reactor 1 enters hydrolysis flash tank 4. Water vapor containing trace amounts of methanol is discharged from the top of hydrolysis flash tank 4. The liquid at the bottom of hydrolysis flash tank 4 flows by gravity to oil-water separator 5, where oil and water are separated. The oil phase (mainly containing undecenoic acid) is sent to subsequent processes, while the aqueous phase is pressurized by water circulation pump 6 and returned to hydrolysis reactor 1, realizing water circulation within the system. The bottom temperature of methanol recovery tower 2 is 180-220℃, the top temperature is 140-170℃, and the pressure of oil-water separator 5 and hydrolysis flash tank 4 are the same.

[0030] Example 1

[0031] Methyl undecenoate and water are continuously added to hydrolysis reactor 1 at a mass ratio of methyl undecenoate to water of 1:3. The temperature of hydrolysis reactor 1 is controlled at 210℃ and the pressure at 1.89MPa. Methyl undecenoate and water react in hydrolysis reactor 1, and the generated methanol and water are vaporized into steam, which enters methanol recovery tower 2. The bottom temperature of methanol recovery tower 2 is controlled at 208℃ and the top temperature at 165℃. The liquid at the bottom of methanol recovery tower 2 flows by gravity back to hydrolysis reactor 1, and part of the steam at the top of methanol recovery tower 2 is cooled by coolers 2-3. The cooled methanol-water is then returned to the methanol recovery tower. Inside tower 2, the methanol water vapor that is not cooled by coolers 2-3 is condensed by methanol water condenser 3 to obtain high-concentration methanol water with a methanol mass concentration of 94.0%. The hydrolysis reaction liquid discharged from the bottom of hydrolysis reactor 1 enters hydrolysis flash tank 4. The pressure of hydrolysis flash tank 4 is controlled at 1.5 MPa. Water vapor containing trace amounts of methanol is discharged from the top of hydrolysis flash tank 4. The liquid at the bottom of hydrolysis flash tank 4 flows by gravity to oil-water separator 5. The pressure of oil-water separator 5 is controlled to be the same as that of hydrolysis flash tank 4. The aqueous phase is pressurized by water circulation pump 6 and returned to hydrolysis reactor 1. The oil phase mainly contains undecenoic acid and is sent to subsequent processes for processing.

[0032] Gas chromatography analysis of the oil phase discharged from oil-water separator 5 showed that the undecenoic acid content was 96.1%, and the conversion rate of undecenoic acid methyl ester was calculated to be 99.1%.

[0033] Example 2

[0034] Differences from Example 1:

[0035] The temperature of hydrolysis reactor 1 was controlled at 200℃ and the pressure at 1.5MPag. The bottom temperature of methanol recovery tower 2 was controlled at 199℃ and the top temperature at 159℃, resulting in high-concentration methanol-water with a methanol mass concentration of 94.3%. The oil phase discharged from oil-water separator 5 was analyzed by gas chromatography, and the undecenoic acid mass content was 95.5%. The conversion rate of undecenoic acid methyl ester was calculated to be 98.2%.

[0036] Example 3

[0037] Differences from Example 1:

[0038] The temperature of hydrolysis reactor 1 was controlled at 215℃ and the pressure at 2.1MPag. The bottom temperature of methanol recovery tower 2 was controlled at 214℃ and the top temperature at 170℃. High-concentration methanol-water with a methanol mass concentration of 93.6% was obtained. The oil phase discharged from oil-water separator 5 was analyzed by gas chromatography, and the undecenoic acid mass content was 94.7%. The conversion rate of undecenoic acid methyl ester was calculated to be 99.4%.

[0039] Example 4

[0040] Differences from Example 1:

[0041] The mass ratio of undecenoic acid methyl ester to water was 1:2, resulting in a high-concentration methanol-water mixture with a methanol mass concentration of 94.0%. The oil phase discharged from oil-water separator 5 was analyzed by gas chromatography, and the undecenoic acid mass content was 95.7%. The conversion rate of undecenoic acid methyl ester was calculated to be 98.5%.

[0042] Comparative Example 1

[0043] Differences from Example 1:

[0044] The methanol recovery tower 2 and methanol-water condenser 3 were removed, and the hydrolysis reactor 1 did not discharge gas. The oil phase discharged from the oil-water separator 5 was analyzed by gas chromatography, and the undecenoic acid mass content was 82.6%. The conversion rate of undecenoic acid methyl ester was calculated to be 88.0%.

Claims

1. A method for the hydrolysis reaction of methyl undecenoate and the recovery of methanol, characterized in that: The raw material, methyl undecenoate, undergoes a hydrolysis reaction with water at 190~215℃ and 1.5~2.2MPa to produce undecenoic acid and methanol; the mass ratio of methyl undecenoate to water is 1:(0.5~4). The raw material undecenoic acid methyl ester, water, and internally circulating water are continuously added to the hydrolysis reactor (1) for hydrolysis reaction. The top gas phase outlet (1-1) of the hydrolysis reactor (1) is connected to the lower gas phase inlet (2-1) of the methanol recovery tower (2), and the bottom liquid phase outlet (2-2) of the methanol recovery tower (2) is connected to the upper liquid phase inlet (1-2) of the hydrolysis reactor (1). The methanol water vapor at the top of the methanol recovery tower (2) is cooled by the cooler (2-3), and the cooled methanol water flows back into the methanol recovery tower (2). The methanol water vapor that is not cooled by the cooler (2-3) is condensed by the methanol water condenser (3) to obtain a methanol aqueous solution. The hydrolysis reaction liquid discharged from the bottom of the hydrolysis reactor (1) enters the hydrolysis flash tank (4). The top of the hydrolysis flash tank (4) discharges methanol-containing water vapor, and the liquid at the bottom of the hydrolysis flash tank (4) flows by gravity into the oil-water separator (5). In the oil-water separator (5), the oil and water are separated. The oil phase is sent to the subsequent process for processing, and the water phase is returned to the hydrolysis reactor (1) after being pressurized by the water circulation pump (6). The bottom temperature of the methanol recovery tower (2) is 180~220℃ and the top temperature is 140~170℃; the pressure of the oil-water separator (5) is the same as that of the hydrolysis flash tank (4).

2. The method for hydrolysis of undecenoic acid methyl ester and methanol recovery according to claim 1, characterized in that: The mass concentration of the methanol is 90-99%.

3. The method for hydrolysis reaction and methanol recovery of undecenoic acid methyl ester according to claim 1, characterized in that: The mass ratio of the raw material undecenoic acid methyl ester to water is 1:(1~3).

Images