阅读说明：本技术 一种异戊二烯基异戊烯基醚的制备方法 (Preparation method of prenyl isopentenyl ether ) 是由 张硕磊 张红涛 何光文 杨国忠 刘英俊 李广琼 方子来 马运果 纪善振 伊健 王 于 2020-07-22 设计创作，主要内容包括：一种异戊二烯基异戊烯基醚的制备方法,所述方法使用底部设有利用氮气对反应液进行混合、气提的氮气混合装置的精馏塔,该方法对从精馏塔底部采出的物料进行闪蒸,并将蒸出的抑制剂的一部分用作冲洗介质,另一部分循环使用。本发明的方法能够显著减少异戊二烯基异戊烯基醚在高温条件下的停留时间,从而减少重组分产生量,还能够实现在线清洗塔内件,减少聚合物在塔内件上的积累。(A process for preparing prenyl isopentenyl ether features that a rectifying tower with nitrogen mixer at its bottom for mixing and stripping the reaction liquid is used, the raw material from the bottom of rectifying tower is flashed, and the inhibitor is used as flushing medium and the rest is cyclically used. The method can obviously reduce the retention time of the prenyl ether under the high-temperature condition, thereby reducing the generation amount of heavy components, realizing the on-line cleaning of the internal parts of the tower and reducing the accumulation of polymers on the internal parts of the tower.)

1. A preparation method of prenyl ether is characterized in that a rectifying tower (C100) is used for preparing the prenyl ether, the rectifying tower (C100) is sequentially provided with a reaction zone (C110), a stripping zone (C120), a rectifying zone (C130) and a tower top (C140) from the tower bottom to the tower top, a tower body of the rectifying tower is provided with a feed inlet and a circulating liquid return opening, the feed inlet is arranged between the stripping zone (C120) and the rectifying zone (C130), the circulating liquid return opening is arranged in the rectifying zone (C130), and a nitrogen mixing device (M100) for mixing and stripping reaction liquid by using nitrogen is arranged in the reaction zone (C110);

wherein the method comprises the steps of:

(1) mixing 3-methyl-2-butene-1-aldehyde diisopentenyl acetal as stream 1 with an inhibitor as stream 2 to obtain stream 3;

(2) mixing said stream 3 with a mixture of catalyst and said inhibitor as stream 5 to obtain stream 4, heating and passing it through said feed inlet into said rectification column (C100) for a cracking reaction, subjecting the resulting reaction product to a nitrogen stripping in said reaction zone by said nitrogen mixing device (M100), withdrawing from the top of said rectification column (C100) a product stream containing prenyl ether as stream 10, withdrawing from the bottom of said rectification column (C100) a stream 7 containing heavy components produced by polymerization, said catalyst and said inhibitor;

(3) the stream 7 is flashed through an evaporator, the stream 11 containing the heavies and catalyst is discharged from the bottom of the evaporator as waste liquid, a portion of the inhibitor distilled off from the evaporator enters the rectification column (C100) as stream 8 from the recycle liquid return port for use as a flushing medium, and another portion is recycled as stream 9 to the stream 2.

2. The preparation method according to claim 1, wherein the nitrogen mixing device (M100) comprises a plurality of coils (M110) and a nitrogen inlet communicated with the plurality of coils, nitrogen enters the coils of the nitrogen mixing device (M100) through the nitrogen inlet, and the top of the coils is provided with a plurality of air outlets (M130) so that nitrogen is ejected from the coils and is mixed and stripped for the reaction liquid in the reaction zone;

preferably, the air outlet (M130) is an air outlet formed at the top of the coil in an inclined manner, so that an included angle alpha between a nitrogen injection direction and a horizontal plane is 5-85 degrees, and preferably alpha is 30-60 degrees;

preferably, the size of the air outlet (M130) is 0.01mm-10mm, preferably 0.03mm-5 mm; the distance between the air outlet holes (M130) is 1cm-50cm, preferably 2cm-15 cm;

preferably, the nitrogen gas injection directions of the coils of adjacent turns are opposite; the spacing between adjacent coils is 1cm to 50cm, preferably 3cm to 15 cm.

3. The preparation method according to claim 1 or 2, wherein the shell of the reaction zone (C110) is a double-layer structure comprising an inner shell (C111) and an outer shell (C112), a hollow cavity (C113) for accommodating a heating medium is formed between the inner shell (C111) and the outer shell (C112), the bottom of the reaction zone (C110) is provided with a feed liquid outlet, the nitrogen mixing device (M100) is arranged at the lower part of the reaction zone, and the distance from the feed liquid outlet is more than 10cm, preferably 20cm-50 cm;

preferably, the inner shell (C111) of the reaction zone is of reduced diameter structure with respect to the other vertical shell parts of the rectification column.

4. A preparation process according to any one of claims 1 to 3, characterized in that in the stream 4 the mass ratio of the 3-methyl-2-butene-1-aldehyde diisopentenyl acetal to the inhibitor is (0.1-0.9):1, preferably (0.2-0.5): 1.

5. The production method according to any one of claims 1 to 4, wherein the catalyst is two or more of nitric acid, phosphoric acid, sulfuric acid, propionic acid, isopentenoic acid, sulfate, phosphate, preferably a mixture of phosphoric acid and propionic acid, wherein the mass ratio of phosphoric acid to propionic acid is (0.1-10):1, preferably (0.5-5):1, wherein the concentration of the catalyst in the stream 4 is 1ppm to 50000ppm, preferably 100ppm to 20000 ppm; wherein in said stream 5 said catalyst is in the range of from 0.0001 wt% to 10 wt%, preferably from 0.0005 wt% to 4 wt%, more preferably from 0.005 wt% to 1.5 wt%, based on the weight of the mixture of said catalyst and said inhibitor.

6. Preparation process according to any one of claims 1 to 5, characterized in that the feed temperature of stream 4 is between 80 and 180 ℃, preferably between 100 and 150 ℃;

the reaction temperature in the reaction zone C110 is 80-180 ℃, preferably 100-150 ℃;

the absolute pressure in the rectification column is 0.1-15kPa (A), preferably 0.2-10kPa (A);

preferably, the temperature of the tower top (C140) is 50-90 ℃.

7. The method according to any one of claims 1 to 6, wherein the inhibitor is an ester, preferably one or more of tert-butyl formate, tert-butyl acetate, tert-butyl isovalerate, trityl acetate, trityl isovalerate, dimethyl isophthalate.

8. The production process according to any one of claims 1 to 7, characterized in that the inhibitor in the stream 8 constitutes from 5% to 40% by weight, preferably from 15% to 30% by weight, of the inhibitor evaporating from the evaporator, the temperature of the stream 8 being from 20 to 80 ℃, preferably from 30 to 70 ℃.

9. The preparation method according to any one of claims 1 to 8, wherein trays selected from one or more of flow-through plates, bubble caps, rotating discs, float valves and sieve plates are arranged in the stripping zone (C120), and the number of trays is 2 to 50, preferably 6 to 30;

said rectification zone (C130) is loaded with packing, said rectification zone (C130) having a theoretical plate number of from 2 to 50, preferably from 6 to 30; the circulating liquid return port is located at 0 to 10 theoretical plates, preferably 2 to 7 theoretical plates.

10. The method according to any one of claims 1 to 9, wherein nitrogen is heated and then introduced into the nitrogen mixing device (M100), and the nitrogen is heated to 80-180 ℃, preferably 100-150 ℃; the nitrogen flow rate is from 1 to 20m/s, preferably from 3 to 15 m/s.

Technical Field

The invention relates to a preparation method of prenyl isopentenyl ether.

Background

The prenyl ether is an important intermediate for synthesizing citral by an isobutene method, and the citral product produced by the method is economic, high in atom utilization rate, high in product yield and strong in competitiveness.

In patent US4288636, the preparation of prenyl ether as intermediate of citral is disclosed, wherein 3-methyl-2-butene-1-aldehyde diisoprenyl acetal is subjected to thermal cracking to obtain prenyl ether and prenol, and the prenol is continuously distilled off to obtain prenyl ether.

Patent WO2008037693 also uses 3-methyl-2-butene-1-aldehyde diisopentenyl acetal obtained by acetalization as a raw material, and obtains prenyl isopentenyl ether and isopentenol through thermal cracking reaction and subsequent reduced pressure distillation, and the ether intermediate is rearranged to obtain citral.

However, the above methods still have the same problems: the prenyl ether is easy to generate rearrangement reaction at a high temperature for a long time to generate citral, prenol generated after the thermal cracking of 3-methyl-2-butene-1-aldehyde diisopentenyl acetal and the citral are subjected to condensation reaction to generate heavy components, the waste liquid rate is up to more than 3%, the yield of the citral product is influenced, and the generated heavy components are easy to accumulate on tower internals and influence the long-period operation of the device.

Therefore, there is a need for a method for producing prenyl ethers with reduced by-products, which can reduce the waste liquid rate, increase the citral yield, and realize long-term operation of the apparatus.

Disclosure of Invention

The invention provides a method for preparing prenyl isopentenyl ether by utilizing 3-methyl-2-butene-1-aldehyde diisopentenyl acetal cleavage. The method utilizes a nitrogen mixing device to mix and strip the reaction liquid, can obviously reduce the retention time of the prenyl isopentenyl ether under the high-temperature condition, thereby reducing the generation amount of heavy components and reducing the waste liquid rate to be below 3 percent, and simultaneously can realize the on-line cleaning of the internal parts of the tower and reduce the accumulation of polymers on the internal parts of the tower.

In order to achieve one aspect of the above object, the invention adopts the following technical scheme:

a preparation method of prenyl ether, said method uses the rectifying column C100 to prepare said prenyl ether, said rectifying column C100 is equipped with reaction zone C110, stripping zone C120, rectifying zone C130 and top of the tower C140 sequentially from bottom to top of the tower, there are feed inlets and circulating liquid to return to the mouth on the tower body of the said rectifying column, the said feed inlet is set up between said stripping zone C120 and said rectifying zone C130, the said circulating liquid returns to the mouth and sets up in the said rectifying zone C130, there is a nitrogen mixing device M100 that utilizes nitrogen to mix, strip the reaction liquid in the said reaction zone C110;

wherein the method comprises the steps of:

(1) mixing 3-methyl-2-butene-1-aldehyde diisopentenyl acetal as stream 1 with an inhibitor as stream 2 to obtain stream 3;

(2) mixing the material flow 3 with a mixture of a catalyst and an inhibitor as a material flow 5 to obtain a material flow 4, heating the material flow and then entering the rectifying tower C100 from the feeding hole for cracking, carrying out nitrogen stripping on the obtained reaction products under the action of the nitrogen mixing device (M100) in the reaction zone, taking out a mixture of isopentenol and prenyl isopentenyl ether as a material flow 10 from the top of the rectifying tower C100, and taking out a material flow 7 containing heavy components generated by polymerization, the catalyst and the inhibitor from the bottom of the rectifying tower C100;

(3) the stream 7 is flashed by means of an evaporator W100, for example a thin film evaporator, from the bottom of which a stream 11 comprising the heavy components and catalyst is discharged as waste liquid, a portion of the inhibitor distilled off by the evaporator W100 being passed as stream 8 from the circulating liquid return to the rectification column C100 for use as flushing medium, and another portion being recycled as stream 9 to the stream 2.

Wherein, the reaction equation for preparing the prenyl isopentenyl ether from the 3-methyl-2-butene-1-aldehyde diisopentenyl acetal is as follows:

in one embodiment, the nitrogen mixing device M100 includes a plurality of coils M110 and a nitrogen inlet communicated with the plurality of coils, nitrogen enters the coils of the nitrogen mixing device M100 through the nitrogen inlet, and a plurality of air outlets M130 are formed at the top of the coils, so that nitrogen is ejected from the pipeline and mixes and strips the reaction solution in the reaction zone. Preferably, the air outlet M130 is an air outlet formed at the top of the coil in an inclined manner, so that an included angle α between the nitrogen injection direction and a horizontal plane is 5 ° to 85 °, and preferably, α is 30 ° to 60 °. Preferably, the size of the air outlet M130 is 0.01mm-10mm, preferably 0.03mm-5 mm. The spacing between the air outlets M130 is 1cm to 50cm, preferably 2cm to 15 cm. Preferably, the nitrogen gas injection directions of the coils of the adjacent circles are opposite, for example, the air outlet holes arranged on the coil of the first circle (the coil of the outermost circle) are oppositely opened with the air outlet holes arranged on the coil of the second circle (the coil of the outermost circle), and the included angle is larger than 0 degrees and smaller than 180 degrees, and preferably 60-120 degrees. The spacing between adjacent coils is 1cm to 50cm, preferably 3cm to 15 cm.

Preferably, the nitrogen mixing device M100 can be adjusted according to the actual application, and the number of turns or the size of the coil pipe is set accordingly.

In the present invention, the size of the air outlet means the diameter of a circle having the same area as the hole.

In one embodiment, the shell of the reaction zone C110 is a double-layer structure including an inner shell C111 and an outer shell C112, a hollow cavity C113 for accommodating a heating medium is formed between the inner shell C111 and the outer shell C112, and a feed liquid outlet is formed at the bottom of the reaction zone C110. Preferably, the inner shell C111 may be integrally formed with the shell of the other part of the rectifying tower. The nitrogen mixing device M100 is disposed at the lower part of the reaction zone, for example, detachably disposed at the lower part of the reaction zone, and the nitrogen mixing device M100 is located at a distance of 10cm or more, preferably 20cm to 50cm, for example, 25cm, 30cm or 40cm from the feed liquid outlet. Preferably, the shell of the reaction zone C110 is further provided with a heating medium inlet and a heating medium outlet, so that the heating medium enters or exits the hollow cavity C113.

In the present invention, in order to make the liquid holding capacity of the reaction zone C110 small and thereby reduce the residence time of prenyl ethers under high temperature conditions, the inner shell C111 of the reaction zone is of a reduced diameter structure with respect to the other vertical shell parts of the rectification column, and has a diameter ratio of 0.5 to 0.9, preferably 0.6 to 0.85.

In one embodiment, the mass ratio of 3-methyl-2-butene-1-aldehyde diisopentenyl acetal to the inhibitor in the stream 4 is (0.1-0.9):1, preferably (0.2-0.5): 1.

Herein, the inhibitors in stream 2 include freshly added inhibitors and inhibitors recycled from stream 9 to stream 2, and the amount of freshly added inhibitors may be greater than or equal to zero.

In one embodiment, the catalyst is two or more of nitric acid, phosphoric acid, sulfuric acid, propionic acid, isopentenoic acid, sulfate, phosphate, preferably a mixture of phosphoric acid and propionic acid, wherein the mass ratio of phosphoric acid to propionic acid (0.1-10):1, preferably (0.5-5):1, wherein the concentration of catalyst in the stream 4 is from 1ppm to 50000ppm, preferably from 100ppm to 20000ppm, such as 100ppm, 300ppm, 500ppm, 1000ppm, 5000ppm, or 10000 ppm; wherein in said stream 5 said catalyst is in the range of from 0.0001 wt% to 10 wt%, preferably from 0.0005 wt% to 4 wt%, more preferably from 0.005 wt% to 1.5 wt%, based on the weight of the mixture of said catalyst and said inhibitor.

In one embodiment, the feed temperature of stream 4 is from 80 to 180 ℃, preferably 100 ℃ and 150 ℃; the reaction temperature is 80-180 ℃, preferably 100-150 ℃.

In the process of the present invention, the absolute pressure in the rectification column, in particular the operating pressure at the top of the column, is from 0.1 to 15kPa (A), preferably from 0.2 to 10kPa (A).

In one embodiment, the inhibitor is an ester, preferably one or more of tert-butyl formate, tert-butyl acetate, tert-butyl isovalerate, trityl acetate, trityl isovalerate, dimethyl isophthalate. The inhibitor can effectively reduce the polymerization of citral and prenol, and can well dissolve heavy components generated by the polymerization of citral and prenol.

In one embodiment, the inhibitor in stream 8 comprises from 5 wt% to 40 wt%, preferably from 15 wt% to 30 wt%, for example 20 wt%, of the inhibitor evaporating from the evaporator at a temperature of from 20 to 80 ℃, preferably from 30 to 70 ℃.

In one embodiment, trays selected from one or more of flow-through plates, bubble caps, rotating discs, float valves and sieve plates are arranged in the stripping zone C120, and the number of the trays is 2 to 50, preferably 6 to 30; the rectification zone C130 is loaded with packing having a theoretical plate number of from 2 to 50, preferably from 6 to 30, which may be random packing or structured packing, preferably structured packing, such as Raschig ring packing. The circulating liquid return port is positioned at the 1 st to 10 th theoretical plates from bottom to top in the packing area, and preferably at the 2 nd to 7 th theoretical plates.

The temperature of the top C140 of the rectifying tower is 50-90 ℃. The tower top temperature and the corresponding operating pressure are beneficial to reducing the occurrence of polymerization reaction in the rectification process.

In the invention, the nitrogen mixing device can enable materials in the reaction kettle to form a boiling state, and can stir the materials at the bottom of the rectifying tower through nitrogen airflow, so that the materials at the bottom of the system are prevented from being mixed and heated unevenly, and meanwhile, the nitrogen plays a role in gas stripping on products in a reaction zone and a rectifying zone in the rising process.

In one embodiment, nitrogen is heated and then introduced into the nitrogen mixing device (M100), and the temperature of the heated nitrogen is 80-180 ℃, preferably 100-150 ℃; the nitrogen flow rate is from 1 to 20m/s, preferably from 3 to 15 m/s.

The invention has the positive effects that:

1. by using the nitrogen mixing device at the bottom, the reaction liquid is mixed by using nitrogen, so that the bottom materials are in a boiling state, and the bottom materials are distributed more uniformly; meanwhile, the nitrogen also plays a role in stripping the materials in the system, so that the retention time of the product in the system is reduced;

2. the main reaction takes place in the rectifying column bottom, and bottom reation kettle is less, and the tower cauldron can carry out the undergauge and handle, can reduce dwell time by a wide margin.

3. The inhibitor is circularly applied, and one part of the inhibitor is used as a flushing medium and enters the rectifying tower, so that heavy components produced in flushing rectification can be dissolved, the accumulation of the heavy components on internal parts of the tower is reduced, the rectification effect is prevented from being reduced, the temperature in the tower can be further reduced, and the residence time of the isoprenyl isopentenyl ether under the high-temperature working condition is reduced.

Drawings

FIG. 1 is a process flow diagram of a continuous reactive distillation method for prenyl ethers according to one embodiment of the present invention.

FIG. 2 is a schematic side view of the structure of a reaction zone of a rectification column according to one embodiment of the present invention.

Fig. 3 is a schematic top view of a nitrogen mixing apparatus according to an embodiment of the present invention.

Fig. 4 is a schematic view of the distribution of air holes on a nitrogen mixing device according to an embodiment of the present invention.

FIG. 5 is a schematic cross-sectional view of a coil of a nitrogen mixing device according to one embodiment of the present invention.

Detailed Description

The following describes the preparation method of prenyl ether crude product provided by the present invention in further detail with reference to the accompanying drawings, but the present invention is not limited thereto.

The rectifying tower C100 is sequentially provided with a reaction zone C110, a stripping zone C120, a rectifying zone C130 and a tower top C140 from the tower bottom to the tower top, a tower tray is arranged in the stripping zone C120, and a filler is loaded in the rectifying zone C130; a feed inlet is arranged on the tower body between the stripping zone C120 and the rectifying zone C130, and a circulating liquid return opening is arranged on the tower body of the rectifying zone C130.

Referring to fig. 2, the shell of the reaction zone C110 is a double-layer structure including an inner shell C111 and an outer shell C112, a hollow cavity C113 for accommodating a heating medium is formed between the inner shell C111 and the outer shell C112, a heating medium inlet and a heating medium outlet for allowing the heating medium to enter or exit the hollow cavity C113 are disposed on the outer shell of the reaction zone C110, and a feed liquid outlet is disposed at the bottom of the reaction zone C110. The lower part of the reaction zone C110 is provided with a nitrogen mixing device M100, and the distance between the nitrogen mixing device M100 and the feed liquid outlet is more than 10cm, so as to prevent the gas binding of the circulating pump.

As shown in fig. 3, the nitrogen mixing device M100 includes a plurality of coils M110 and a nitrogen inlet communicated with the plurality of coils, and a plurality of outlet holes M130 for injecting nitrogen are formed at the top of the coils, where the outlet holes M130 are inclined at the top of the coils, so that an included angle α between the nitrogen injection direction and the horizontal plane is 5 ° to 85 °. The size of the air outlet M130 is 0.01mm-10 mm. The distance between the air outlet holes M130 is 1cm-50 cm.

In one embodiment, adjacent turns of the coil have opposite nitrogen injection directions with an included angle greater than 0 ° and less than 180 °, preferably 60-120 °. The distance between adjacent coils is 1cm-50cm, preferably 3cm-15 cm.

In one embodiment, a part of the coil pipe of the nitrogen mixing device M100 extends out of the rectifying tower body, and the nitrogen inlet is disposed on the part of the pipe extending out of the rectifying tower body, specifically, it may be a nitrogen inlet pipe connected with a nitrogen source, and the nitrogen inlet pipe is connected with the coil pipe for supplying nitrogen.

Specifically, a mounting port for mounting the nitrogen inlet pipe may be provided on the shell of the reaction zone C110, i.e., the nitrogen inlet pipe may extend into the reaction zone through the mounting port and be connected with the coil pipe.

Referring to fig. 1, the continuous reactive distillation method of isoprenyl isopentenyl ether of the invention comprises the steps of fully mixing a material flow 1 of 3-methyl-2-butene-1-aldehyde diisopentenyl acetal with a material flow 2 of an inhibitor in a mixing tank D100 to obtain a material flow 3, mixing the material flow 3 with a material flow 5 of a catalyst and inhibitor mixture in a static mixer S100, and then feeding the mixture into a heater E100, wherein the heater E100 is arranged at a position as close to a rectifying tower C100 as possible, heating the mixture in the heater E100 to a reaction temperature, feeding the mixture into the rectifying tower C100 as a material flow 4 for reaction, raising light components generated by the reaction to the top of the tower, and taking out a material flow 10 as a product; after being heated by a heater E200, the nitrogen gas flow 6 enters a reaction zone at the bottom of a rectifying tower C100 from a nitrogen mixing device M100, the nitrogen gas flow stirs materials at the bottom of the rectifying tower, and meanwhile, the nitrogen gas lifts light components to the top of the rectifying tower in the rising process; the catalyst, the inhibitor and the heavy components generated by the side reaction are discharged from the bottom of the rectifying tower C100 as a material flow 7, enter the thin film evaporator W100 through a circulating pump P100 for flash evaporation, a material flow 11 containing the heavy components and the catalyst is obtained from the bottom of the thin film evaporator W100 and is taken as a waste liquid discharge system, the inhibitor which is flashed out is discharged from the upper part or the top of the thin film evaporator W100, one part of the inhibitor which is obtained by flash evaporation is circulated to the material flow 2 as a material flow 9, the other part of the inhibitor is taken as a material flow 8 and enters the middle part (namely a rectifying zone) of the rectifying tower from a circulating liquid return port, the polymerization reaction in the rectifying zone C130 is inhibited through middle-section reflux, and the.

The invention will now be further illustrated by means of specific examples.

The gas chromatography conditions in the present invention are as follows:

a chromatographic column: agilent HP-5 (specification of 30m × 0.32mm × 0.25mm)

Sample inlet temperature: 280 deg.C

The split ratio is as follows: 30:1

Column flow rate: 1.5ml/min

Column temperature: 0.5min at 100 DEG C

Increasing the temperature to 260 ℃ at 15 ℃/min and keeping the temperature for 8min

Detector temperature: 280 ℃, H2 flow: 35ml/min

Air flow rate: 350ml/min

And (3) reagent sources:

phosphoric acid and propionic acid are from Xiong science corporation

Other reagents were from Aladdin reagents (Shanghai) Co., Ltd