CN1268627C

CN1268627C - Process for preparing 1.8-diazadicyclo [5,4,0] -7 undecene

Info

Publication number: CN1268627C
Application number: CN 200310115849
Authority: CN
Inventors: 马震; 马斌; 杨文库; 李全忠; 刘忠慧; 孙德彦
Original assignee: JILIN PETROCHEMICAL DESIGN AND RESEARCH INST
Current assignee: JILIN PETROCHEMICAL DESIGN AND RESEARCH INST
Priority date: 2003-12-01
Filing date: 2003-12-01
Publication date: 2006-08-09
Anticipated expiration: 2023-12-01
Also published as: CN1546492A

Abstract

The present invention belongs to a method for preparing 1.8-dinitrogen bicyclo (5, 4, 0)-7 undecene (DBU). In the method, caprolactam and acrylonitrile are used as initial raw materials to carry out addition reaction, hydrogenation reaction and cyclization reaction, a catalyst containing Al, Ni, Fe and Cr is used as a hydrogenation catalyst, and a bubbling bed type hydrogenation reactor is used. The present invention has the advantages that reaction pressure is lowered from the original 9.0 to 9.5MPa to 1.0 to 3.0Mpa, DBU total yield is improved from 30.2% to 70%, requirements to reaction equipment is reduced, production period is shortened, and 'three wastes' are reduced.

Description

Process for the preparation of 1, 8-diazabicyclo [5, 4, 0]undec-7-enes

Technical Field

The invention belongs to a method for preparing 1, 8-diazabicyclo [5, 4, 0]undec-7-ene (DBU).

Background

DBU is amidine with a diheterocyclic structure, is an important organic synthesis intermediate, can be widely applied to various reactions such as elimination, isomerization, condensation, esterification, cyclization, polymerization and the like, and has a structural formula as follows:

the relative molecular weight is 152.24, the boiling point is 259-260 ℃, the density is 1.0192, and the liquid is colorless or light yellow oily liquid. The preparation of DBU adopts a caprolactam method at home and abroad, namely, the DBU product is prepared by taking caprolactam and acrylonitrile as raw materials through three steps of reactions of addition, hydrogenation and cyclization, and the specific reaction process is as follows:

however, the total yield level of the reaction is greatly different due to the adoption of different catalysts and different process conditions adopted in each step of the reaction, and Wuyi nationality et al is in the journal of Chinese medicine industry, 1997, 28 (12): 556 discloses that Raney Ni-potassium borohydride is adopted as a reducing agent in the hydrogenation reaction, products in each step need to be refined and then converted in the next step of synthesis process, the total reaction yield is 30.3%, and the product cost is high; the Shanghai pharmaceutical industry institute, Yuyun, etc. adopts Raney Ni as a catalyst in hydrogenation reaction, the hydrogenation pressure is up to 9.0-10.0MPa, and products in each step can be transferred into the next synthesis procedure after being refined, and the total reaction yield is 48.4%. Therefore, the prior preparation processes have the problems of low yield, high requirement on reaction equipment and the like.

Disclosure of Invention

The invention aims to provide a preparation method of 1, 8-diazabicyclo [5, 4, 0]undec-7-ene.

The method is mainly characterized in that firstly, Al, Ni, Fe and Cr catalysts are adopted in hydrogenation reaction, the hydrogenation reaction pressure is only 1.0-2.5MPa, secondly, due to the adoption of proper process conditions, products in each reaction step can be directly transferred into the next synthesis process without refining treatment, so that intermediate operation links are reduced, thirdly, the reaction yield is higher and can reach 70%, the production cost is reduced, and the difficulty of the post-treatment process is reduced.

The invention realizes a method for preparing DBU by addition, hydrogenation and cyclization reactions of caprolactam and acrylonitrile. The specific synthesis process is as follows:

addition reaction: adding 25-40 wt% of toluene into caprolactam, adding 0.5-2 wt% of alkali as a catalyst, wherein the alkali is sodium hydroxide or potassium hydroxide, dropwise adding acrylonitrile at the temperature of 50-60 ℃,and the using amount of the acrylonitrile is 1-1.2 times of that of the caprolactam, evaporating to remove a solvent after the dropwise adding is finished, and cooling and filtering to obtain a crude product of intermediate cyanoethyl caprolactam;

hydrogenation reaction: taking Al, Ni, Fe and Cr alloy catalyst, the mass percent is 50: 40: 7: 3, adding 10-15 times of distilled water, stirring and heating to 85 ℃, beginning to drip alkali liquor, wherein the alkali liquor is sodium hydroxide or potassium hydroxide aqueous solution, the alkali dosage is 1-1.5 times of the weight of the alloy, one half of the alkali liquor is prepared into 10-15 wt% alkali liquor, the other half of the alkali liquor is prepared into 20-25 wt% alkali liquor, controlling the reaction temperature to be 85-90 ℃, firstly dripping alkali liquor with low concentration, then dripping alkali liquor with high concentration, after all alkali liquor is dripped, heating to 90-95 ℃, reacting for 1hr, cooling, pouring supernatant, sequentially washing for three times by using distilled water and absolute ethyl alcohol respectively, and obtaining the hydrogenation catalyst; mixing the prepared hydrogenation catalyst, the cyanoethyl caprolactam crude product and ethanol according to the mass ratio of 2-10: 100: 80-120, pumping the mixture into a bubbling bed type hydrogenation reactor, starting a hydrogen circulator after gas replacement to bubble and blow hydrogen from the bottom of the reactor to perform high-pressure hydrogenation reaction, wherein the reaction pressure is 1.5-2.5Mpa, the reaction temperature is 90-120 ℃, the reaction time is 1-2hr, emptying the reactor after the reaction is finished, settling and separating the catalyst, and continuously using the catalyst, and removing ethanol from the reaction liquid to obtain an intermediate aminopropylcaprolactam;

and (3) cyclization reaction: adding 0.5-2 wt% of catalyst antimony trioxide into the prepared intermediate aminopropyl caprolactam, reacting for 20-30hr at the temperature of 150-160 ℃ until no water is generated, and refining to obtain the finished product DBU.

Detailed Description

Example 1

200g of caprolactam and 75g of toluene are added into a 500ml four-mouth bottle, the temperature is raised to 55 ℃, 1g of sodium hydroxide catalyst is added under stirring, 98g of acrylonitrile is added dropwise, the reaction temperature is controlled to be 57 +/-2 ℃, after the reaction is finished, the toluene is steamed, the temperature is reduced and the intermediate cyanoethyl caprolactam crude product is obtained after filtration, the yield is 93 percent (calculated by caprolactam), and the caprolactam conversion rate is 99 percent;

adding 600ml of distilled water into a 2000ml four-mouth bottle, adding 50g of four-component catalyst raw powder, stirring, heating to 90 ℃, beginning to dropwise add sodium hydroxide solution with the initial concentration of 15 percent, dropwise adding 200ml in total, dropwise adding 140ml of 25 percent sodium hydroxide solution, controlling the temperature to 88 +/-2 ℃, heating to 94 +/-1 ℃ after all the sodium hydroxide solution is completely dripped, reacting for 1hr, cooling, pouring out supernatant, sequentially washing with distilled water and absolute ethyl alcohol for three times respectively to obtain a hydrogenation catalyst;

mixing the prepared hydrogenation catalyst, cyanoethyl caprolactam and ethanol according to the proportion of 5: 100, pumping into a hydrogenation reactor, replacing gas, starting a hydrogen circulator to perform high-pressure hydrogenation reaction at the reaction pressure of 2.5Mpa and the reaction temperature of 100 +/-5 ℃ for 1hr, emptying after the reactionis finished, settling and separating the catalyst, and continuously using the catalyst, thereby obtaining an intermediate aminopropyl caprolactam after dealcoholization of reaction liquid, wherein the yield is 95%.

A1000 ml four-mouth bottle is added with a reflux condenser and a water separator, 360g of aminopropyl caprolactam and 3.6g of antimony trioxide are added, the reaction is carried out at the temperature of 155 +/-5 ℃ for 20 hours until no water is generated, and a finished product DBU is obtained by refining, wherein the total yield is 70%.

Example 2

Adding 200g of caprolactam and 75g of toluene into a 500ml four-mouth bottle, heating to 55 ℃, adding 1g of potassium hydroxide catalyst while stirring, simultaneously dropwise adding 94g of acrylonitrile, controlling the reaction temperature to be 57 +/-2 ℃, and after the reaction is finished, evaporating the toluene, cooling and filtering to obtain an intermediate cyanoethyl caprolactam crude product, wherein the yield is 89% calculated by caprolactam, and the caprolactam conversion rate is 96%;

adding 600ml of distilled water into a 2000ml four-mouth bottle, adding 50g of four-component catalyst raw powder, stirring and heating to 85 ℃, beginning to dropwise add a potassium hydroxide solution, controlling the concentration of the initial potassium hydroxide solution to be 15%, dropwise adding 200ml in total, dropwise adding 140ml of 25% alkali liquor, controlling the temperature to be 85 +/-2 ℃, after all the potassium hydroxide solution is completely dripped, heating to 90 +/-1 ℃, reacting for 1hr, cooling, pouring out supernatant, sequentially washing with distilled water and absolute ethyl alcohol for three times respectively to obtain a hydrogenation catalyst;

mixing the prepared hydrogenation catalyst, cyanoethyl caprolactam and ethanol according to the ratio of 2: 100:80, pumping into a hydrogenation reactor, performing gas replacement, starting a hydrogen circulator to perform high-pressure hydrogenation reaction at the reaction pressure of 1.5Mpa and the reaction temperature of 115 +/-5 ℃ for 2hr, emptying after the reaction is finished, settling and separating the catalyst, and continuously using the catalyst, thus obtaining an intermediate aminopropyl caprolactam after dealcoholization of reaction liquid, wherein the yield is 93%;

a1000 ml four-mouth bottle is added with a reflux condenser and a water separator, 360g of aminopropyl caprolactam and 5.4g of antimony trioxide are added, the reaction is carried out at the temperature of 155 +/-5 ℃ for 20 hours until no water is generated, and a finished product DBU is obtained by refining, wherein the total yield is 64%.

Example 3

Adding 200g of caprolactam and 75g of toluene into a 500ml four-mouth bottle, heating to 50 ℃, adding 1g of sodium hydroxide catalyst while stirring, simultaneously dropwise adding 104g of acrylonitrile, controlling the reaction temperature to be 52 +/-2 ℃, and after the reaction is finished, evaporating the toluene, cooling and filtering to obtain an intermediate cyanoethyl caprolactam crude product, wherein the yield is 90 percent (calculated by caprolactam), and the caprolactam conversion rate is 99 percent;

adding 600ml of distilled water into a 2000ml four-mouth bottle, adding 50g of four-component catalyst raw powder, stirring and heating to 90 ℃, beginning to dropwise add sodium hydroxide solution, wherein the initial concentration of the sodium hydroxide solution is 10%, dropwise adding 310ml in total, dropwise adding 140ml of 25% sodium hydroxide solution, controlling the temperature to 88 +/-2 ℃, after all the sodium hydroxide solution is completely dripped, heating to 94 +/-1 ℃, reacting for 1hr, cooling, pouring out supernatant, and sequentially washing with distilled water and absolute ethyl alcohol for three times respectively to obtain a hydrogenation catalyst;

mixing the prepared hydrogenation catalyst, cyanoethyl caprolactam and ethanol according to the proportion of 8: 100: 120, pumping into a hydrogenation reactor, performing gas replacement, starting a hydrogen circulator to perform high-pressure hydrogenation reaction at the reaction pressure of 1.0Mpa and the reaction temperature of 110 +/-5 ℃ for 1.5hr, emptying after the reaction is finished, settling and separating the catalyst, and continuously using the catalyst, wherein the yield of the intermediate aminopropyl caprolactam is 94 percent after dealcoholization of reaction liquid;

a1000 ml four-mouth bottle is added with a reflux condenser and a water separator, 360g of aminopropyl caprolactam and 2.5g of antimony trioxide are added, the reaction is carried out at the temperature of 155 +/-5 ℃ for 25 hours until no water is generated, and a finished product DBU is obtained by refining, wherein the total yield is 66%.

Claims

1. A preparation method of 1, 8-diazabicyclo [5, 4, 0]undec-7-ene comprises the following steps:

caprolactam and acrylonitrile are subjected to addition, hydrogenation and cyclization reactions, and the synthesis method is characterized in that Al, Ni, Fe and Cr catalysts are adopted, and the specific synthesis process is as follows:

addition reaction: adding 25-40 wt% of toluene into caprolactam, adding 0.5-2 wt% of alkali as a catalyst, dropwise adding acrylonitrile at the temperature of 50-60 ℃, wherein the using amount of the acrylonitrile is 1-1.2 times of that of the caprolactam, evaporating to remove a solvent after the dropwise adding is finished, and cooling and filtering to obtain a crude product of intermediate cyanoethyl caprolactam;

hydrogenation reaction: taking Al, Ni, Fe and Cr alloy catalyst, the mass percent is 50: 40: 7: 3, adding 10-15 times of distilled water, stirring and heating to 85 ℃, beginning to drip alkali liquor, wherein the alkali liquor is sodium hydroxide or potassium hydroxide aqueous solution, the alkali dosage is 1-1.5 times of the weight of the alloy, one half of the alkali liquor is prepared into 10-15 wt% alkali liquor, the other half of the alkali liquor is prepared into 20-25 wt% alkali liquor, controlling the reaction temperature to be 85-90 ℃, firstly dripping alkali liquor with low concentration, then dripping alkali liquor with high concentration, after all alkali liquor is dripped, heating to 90-95 ℃, reacting for 1hr, cooling, pouring supernatant, sequentially washing for three times by using distilled water and absolute ethyl alcohol respectively, and obtaining the hydrogenation catalyst; mixing the prepared hydrogenation catalyst, the cyanoethyl caprolactam crude product and ethanol according to the mass ratio of 2-10: 100: 80-120, pumping into a bubbling bed hydrogenation reactor, performing gas replacement, starting a hydrogen circulator to perform high-pressure hydrogenation reaction at the reaction pressure of 1.5-2.5Mpa and the reaction temperature of 90-120 ℃ for 1-2hr, emptying after the reaction is finished, continuously using the catalyst after settling separation, and removing ethanol from the reaction liquid to obtain an intermediate aminopropylcaprolactam;

and (3) cyclization reaction: adding 0.5-2wt% of catalyst antimony trioxide into the prepared intermediate aminopropylcaprolactam, reacting for 20-30hr at the temperature of 150 ℃ and 160 ℃ until no water is generated, and refining to obtain the finished product of 1, 8-diazabicyclo [5, 4, 0]undec-7-ene.