CN107540548B - Method for preparing dibutyl carbonate - Google Patents
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Abstract
The invention belongs to the technical field of chemical synthesis, and particularly relates to a method for preparing dibutyl carbonate. Preparing a reaction material solution from the cosolvent, n-butanol and urea, filling a Cu-Zn-Al catalyst, pumping the reaction material solution into a reactor by using a metering pump, and carrying out reaction in a continuous flow fixed bed to obtain the catalyst. The addition of the cosolvent can lead the reaction materials to be in a homogeneous system, the reaction can be continuously carried out in a large scale, and the catalyst and the product do not need to be separated.
Description
Technical Field
The invention belongs to the technical field of chemical synthesis, and particularly relates to a method for preparing dibutyl carbonate.
Background
Dibutyl carbonate is colorless transparent liquid, has mild smell and is insoluble in water, thus being an important solvent and an organic synthesis intermediate; the solvent can be used as the solvent of the electrolyte in the lithium ion battery, and has the advantages of improving the stability and safety of the battery compared with other solvents; it can also be used as the base material of lubricating oil for metal oil removal and leather treatment. Dibutyl carbonate and bisphenol A are used as raw materials, organic tin is used as a catalyst, and polycarbonate can be synthesized. The industrial synthesis method of dibutyl carbonate mainly includes phosgene method, oxidative carbonylation method and ester exchange method. Phosgene methods have the disadvantages of extremely toxic raw materials, long operation cycle, severe corrosion of equipment by-products and the like, and are being gradually eliminated. In the oxidative carbonylation method, noble metals such as palladium and compounds thereof are generally used as catalysts, and the catalysts are not easy to recycle. The transesterification method adopts dimethyl carbonate as a raw material, so that the raw material cost is high, and the reaction is a parallel series reaction, so that a reaction rectification method is required to improve the reaction yield.
The urea alcoholysis method is a technology for synthesizing alkyl carbonate which is emerging in recent years, and has strong competitiveness because urea which is one of raw materials belongs to a large amount of chemical raw materials, has wide sources and low price, and in addition, carbon dioxide is consumed in the urea preparation process, greenhouse gases are indirectly utilized in the reaction, carbon emission is reduced, the problems of resources and energy sources can be solved, and the environmental pressure is reduced. The process routes for preparing the related alkyl carbonates by reacting urea with methanol, ethanol and butanol are all reported.
CN102093221A discloses a method for synthesizing dibutyl carbonate, which takes butyl carbamate and n-butanol as raw materials, takes MgO as a catalyst, and CO2The reaction promoter and the ammonia absorbent react in a kettle type reactor, the conversion rate of the butyl carbamate reaches 99 percent, but the price of the butyl carbamate is higher than that of the dimethyl carbonate product. CN102557948A and CN102464588A adopt a reaction separation system consisting of a kettle reactor and a gas storage-condensation-carbamate amine catcher, and adopt a two-stage heating mode to control the reaction temperature, so as to obtain higher dibutyl carbonate yield, but still have the problems of complex process and higher molar ratio of butanol to urea. CN102093221A, CN102557948A and CN102464588A all have problems at the same time: the reaction is carried out intermittently, which limits the scale and continuity of production and simultaneously has the problem that the catalyst needs to be separated from the reaction system after the reaction is finished. The fixed bed reactor can better solve the problems of large scale and continuity of the reaction, and simultaneously, the problem of separation of the catalyst and the product does not exist, and CN101121659B reports that urea and methanol are used as raw materials, and the fixed bed reactor is adopted to synthesize the dimethyl carbonate.
As the carbon chain grows, the solubility of urea in monohydric alcohols C1, C2, C3 and C4 is gradually reduced, the solubility of urea in n-butyl alcohol is very low, 2mol of n-butyl alcohol and 1mol of urea are needed for generating 1mol of dibutyl carbonate according to a stoichiometric coefficient, and the measured dissolution test result shows that n-butyl alcohol and urea with the molar ratio of 2:1 still have a large amount of urea solid under the conditions of heating and ultrasonic oscillation. The urea is required to be dissolved in the butanol by adopting the fixed bed reactor, and the mixed solution is pumped into the reactor by adopting the delivery pump, so that the problem of the solubility of the urea in the butanol is limited, and no relevant report of the application of the fixed bed reactor in a route for preparing the dibutyl carbonate by the reaction of the urea and the n-butanol is found.
Disclosure of Invention
The invention aims to provide a method for preparing dibutyl carbonate, which solves the problem that urea is difficult to dissolve in n-butanol, the reaction can be carried out continuously and in large scale, and a catalyst and a product do not need to be separated.
The method for preparing the dibutyl carbonate comprises the steps of preparing a reaction material solution from a cosolvent, n-butanol and urea, filling a Cu-Zn-Al catalyst, pumping the reaction material solution into a reactor by using a metering pump, and carrying out reaction in a continuous flow fixed bed to obtain the dibutyl carbonate.
The cosolvent is one or more of dimethylformamide, sulfolane, N-methylpyrrolidone or dimethyl sulfoxide.
The mol ratio of the urea to the cosolvent is 1: 0.5-10.
The molar ratio of the n-butanol to the urea is 2.5-6: 1.
The Cu-Zn-Al catalyst is calculated by taking the weight of the catalyst as 100 percent,
CuO 25-60％
ZnO 25-60％
Al2O310-30％。
the Cu-Zn-Al catalyst is preferably 100 percent of the weight of the catalyst
CuO 30-50％
ZnO 30-50％
Al2O315-25％。
The preparation method of the Cu-Zn-Al catalyst comprises the steps of respectively preparing nitrates of Cu, Zn and Al into 0.1-1mol/L solutions, and mixing to obtain mother liquor; na (sodium sulfate)2CO3Preparing 0.1-1mol/L solution, dripping into mother liquor, filtering, precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 300-450 ℃ for 3-6 hours, adding graphite, tabletting and forming to obtain the Cu-Zn-Al catalyst.
The loading of the Cu-Zn-Al catalyst is 40 ml.
The airspeed of the reaction material solution is 0.8-5h-1。
The reaction temperature is 150-210 ℃, the reaction pressure is 0.03-0.8MPa, and the reaction time is 24-72 h.
The reaction pressure is controlled by continuously flowing CO2Maintenance of CO2The space velocity is 500-2000h-1。
The molar ratio of urea to co-solvent is preferably: 1:1-5, the molar ratio of n-butanol to urea is preferably: 3-5:1, and the preferred space velocity of the reaction mass solution is 1-4h-1，CO2The space velocity is preferably 800-1800h-1The reaction temperature is preferably 180-205 ℃, the reaction pressure is preferably 0.1-0.3MPa, and the reaction time is preferably 30-70 h.
Compared with the prior art, the invention has the following beneficial effects:
1. the addition of the cosolvent can lead the reaction materials to be in a homogeneous system, the reaction can be continuously carried out in a large scale, and the catalyst and the product do not need to be separated.
2. The preparation method of the catalyst is simple, and the used raw materials are all commercial products, so that the catalyst is suitable for industrial large-scale production.
Detailed Description
The present invention is further described below with reference to examples.
Example 1
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 211.4g, 293.8g and 367.7g are respectively prepared into 1mol/L aqueous solution and mixed to obtain mother liquor; 301.1gNa was weighed2CO3Preparing 0.5mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝35％：40％：25％。
Preparing a reaction material solution according to the molar ratio of the cosolvent dimethyl formamide to the urea to the n-butyl alcohol of 2:1:3, wherein the loading amount of the catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1h-1，CO2Space velocity of 900h-1The reaction temperature is 180 ℃, the reaction pressure is 0.1MPa, and the reaction is carried outThe time is 24 h. The urea conversion was 99% and the dibutyl carbonate yield was 75%.
Example 2
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 181.2g, 367.2g and 294.2g are respectively prepared into 1mol/L aqueous solution and mixed to obtain mother solution; weighing 335.1gNa2CO3Preparing 1mol/L aqueous solution, dripping the aqueous solution into mother solution, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝30％：50％：20％。
Preparing a reaction material solution according to the molar ratio of cosolvent dimethyl sulfoxide, urea and n-butanol of 3:1:4, wherein the loading amount of a catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1h-1，CO2The space velocity is 1000h-1The reaction temperature is 185 ℃, the reaction pressure is 0.2MPa, and the reaction time is 30 h. The urea conversion rate was 99% and the dibutyl carbonate yield was 80%.
Example 3
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 199.3g, 323.2g and 485.5g, which are respectively prepared into 0.8mol/L aqueous solution and mixed to obtain mother liquor; weighing 408.3gNa2CO3Preparing 1mol/L aqueous solution, dripping the aqueous solution into mother solution, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 400 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝30％：40％：30％。
Preparing a reaction material solution according to the molar ratio of cosolvent sulfolane, urea and n-butanol of 3:1:4, wherein the loading amount of a catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1h-1，CO2The space velocity is 1200h-1The reaction temperature is 190 ℃, the reaction pressure is 0.2MPa, and the reaction time is 40 h. The urea conversion was 97% and the dibutyl carbonate yield was 83%.
Example 4
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 241.6g, 293.8g and 294.2g are respectively prepared into 0.5mol/L aqueous solution and mixed to obtain mother liquor; weighing 335.4gNa2CO3Preparing 0.5mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝30％：40％：20％。
Preparing a reaction material solution according to the molar ratio of cosolvent N-methylpyrrolidone to dimethyl sulfoxide to urea to N-butanol of 1:2:1:3.5, wherein the loading amount of the catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1.5h-1，CO2Space velocity of 1400h-1The reaction temperature is 200 ℃, the reaction pressure is 0.28MPa, and the reaction time is 50 h. The urea conversion was 96% and the dibutyl carbonate yield was 75%.
Example 5
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 407.7g, 385.6g and 441.3g, which are respectively prepared into 0.8mol/L aqueous solution and mixed to obtain mother liquor; 503.3gNa was weighed out2CO3Preparing 0.8mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝45％：35％：20％。
Preparing a reaction material solution according to the mol ratio of cosolvent N-methyl pyrrolidone, sulfolane, urea and N-butanol of 1:3:1:4, wherein the loading amount of the catalyst is 40ml, and reactingIn a continuous flow fixed bed, the liquid space velocity is 2h-1，CO2The space velocity is 1000h-1The reaction temperature is 200 ℃, the reaction pressure is 0.3MPa, and the reaction time is 60 h. The urea conversion was 97% and the dibutyl carbonate yield was 81%.
Example 6
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 291.7g, 304.1g and 372.2g are respectively prepared into 0.5mol/L aqueous solution and mixed to obtain mother liquor; weighing 394.1gNa2CO3Preparing 0.5mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝42％：36％：22％。
Preparing a reaction material solution according to the molar ratio of cosolvent dimethyl formamide, dimethyl sulfoxide, urea and n-butanol of 1:3:1:4, wherein the loading amount of a catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1h-1，CO2The space velocity is 1200h-1The reaction temperature is 200 ℃, the reaction pressure is 0.3MPa, and the reaction time is 60 h. The urea conversion was 96.5% and the dibutyl carbonate yield was 79.5%.
Example 7
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 202.9g, 401.1g and 247.1g are respectively prepared into 0.4mol/L aqueous solution and mixed to obtain mother liquor; weighing 336.7g Na2CO3Preparing 0.4mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 400 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝32％：52％：16％。
As cosolvents N-methylpyrrolidone, urea and N-methyl pyrrolidoneThe mol ratio of butanol is 3:1:4, a reaction material solution is prepared, the loading amount of the catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1.3h-1，CO2Space velocity of 1300h-1The reaction temperature is 199 ℃, the reaction pressure is 0.25MPa, and the reaction time is 50 h. The urea conversion was 98% and the dibutyl carbonate yield was 87.5%.
Example 8
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 347.3g, 330.5g and 165.5g, respectively preparing 0.9mol/L aqueous solution, and mixing to obtain mother liquor; weighing 340.3gNa2CO3Preparing 0.9mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 440 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝46％：36％：18％。
Preparing a reaction material solution according to the mol ratio of cosolvent N-methyl pyrrolidone, urea and N-butanol of 4:1:4, wherein the loading amount of a catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 2h-1，CO2The space velocity is 1500h-1The reaction temperature is 190 ℃, the reaction pressure is 0.25MPa, and the reaction time is 60 h. The urea conversion was 95% and the dibutyl carbonate yield was 82.7%.
Example 9
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 190.3g, 330.5g and 198.6g are respectively prepared into 0.7mol/L aqueous solution and mixed to obtain mother liquor; weighing 285.4gNa2CO3Preparing 0.7mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝35％：50％：15％。
Preparing a reaction material solution according to the molar ratio of cosolvent sulfolane, dimethylformamide, urea and n-butanol of 1:3:1:5, wherein the loading amount of a catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1.5h-1，CO2Space velocity of 1400h-1The reaction temperature is 190 ℃, the reaction pressure is 0.15MPa, and the reaction time is 70 h. The urea conversion was 98.6% and the dibutyl carbonate yield was 89.4%.
Example 10
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 181.2g, 403.9g and 220.7g, which are respectively prepared into 0.5mol/L aqueous solution and mixed to obtain mother liquor; weighing 316.9gNa2CO3Preparing 0.5mol/L aqueous solution, dripping the aqueous solution into mother liquor, filtering and precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 450 ℃, adding graphite tablets for forming to obtain a phi 3 x 3Cu-Zn-Al catalyst, wherein the catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝30％：55％：15％。
Preparing a reaction material solution according to the molar ratio of cosolvent sulfolane, dimethyl sulfoxide, urea and n-butanol of 4:1:1:4.5, wherein the loading amount of a catalyst is 40ml, the reaction is carried out in a continuous flow fixed bed, and the liquid airspeed is 1.5h-1，CO2Space velocity of 1300h-1The reaction temperature is 195 ℃, the reaction pressure is 0.3MPa, and the reaction time is 65 hours. The urea conversion was 98.2% and the dibutyl carbonate yield was 88.9%.
Comparative example 1
Preparation of the catalyst: separately weighing Cu (NO)3)2.3H2O、Zn(NO3)2.6H2O、Al(NO3)3.9H2O: 407.7g, 385.6g and 441.3g, which are respectively prepared into 0.8mol/L aqueous solution and mixed to obtain mother liquor; 503.3gNa was weighed out2CO3Preparing 0.8mol/L aqueous solution, dripping into mother liquor, filtering, precipitating, drying at 120 deg.C, pulverizing to 200 mesh, calcining at 450 deg.C, adding graphite, tabletting to obtain phi 3 x 3Cu-Zn-Al catalystThe catalyst comprises the following components in percentage by weight: CuO: ZnO: al (Al)2O3＝45％：35％：20％。
The method comprises the steps of mixing two raw materials according to the molar ratio of 1:4 of urea to n-butanol without adding any cosolvent, heating at 60 ℃ for 4 hours under the condition of stirring, and still adding a large amount of undissolved urea, so that under the condition of not adding the cosolvent, a conveying pump cannot be adopted to pump the mixed solution of urea and butanol in a preset proportion into a reactor for reaction.
Claims (6)
1. A method for preparing dibutyl carbonate is characterized in that a cosolvent, n-butanol and urea are prepared into a reaction material solution, a Cu-Zn-Al catalyst is filled in the reaction material solution, the reaction material solution is pumped into a reactor by a metering pump, and the reaction is carried out in a continuous flow fixed bed to obtain the dibutyl carbonate;
the cosolvent is one or more of dimethylformamide, sulfolane, N-methylpyrrolidone or dimethyl sulfoxide;
the mol ratio of the urea to the cosolvent is 1: 0.5-10;
the Cu-Zn-Al catalyst is calculated by taking the weight of the catalyst as 100 percent,
CuO 25-60％
ZnO 25-60％
Al2O310-30％；
the preparation method of the Cu-Zn-Al catalyst comprises the steps of respectively preparing nitrates of Cu, Zn and Al into 0.1-1mol/L solutions, and mixing to obtain mother liquor; na (sodium sulfate)2CO3Preparing 0.1-1mol/L solution, dripping into mother liquor, filtering, precipitating, drying at 120 ℃, crushing to 200 meshes, roasting at 300-450 ℃ for 3-6 hours, adding graphite, tabletting and forming to obtain the Cu-Zn-Al catalyst.
2. The method for preparing dibutyl carbonate according to claim 1, characterized in that the molar ratio of n-butanol to urea is 2.5-6: 1.
3. The method for preparing dibutyl carbonate according to claim 1, characterized in that the loading of the Cu-Zn-Al catalyst is 40 ml.
4. The method for preparing dibutyl carbonate according to claim 1, characterized in that the space velocity of the reaction mass solution is 0.8-5h-1。
5. The method for preparing dibutyl carbonate according to claim 1, characterized in that the reaction temperature is 150-210 ℃, the reaction pressure is 0.03-0.8MPa, and the reaction time is 24-72 h.
6. The process for preparing dibutyl carbonate according to claim 5, characterized in that the reaction pressure is passed through the continuously flowing CO2Maintenance of CO2The space velocity is 500-2000h-1。
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1121659A (en) * | 1995-07-13 | 1996-05-01 | 曾光橦 | Method for realizing exceeding-normal coding |
| JP2001354624A (en) * | 2000-06-12 | 2001-12-25 | Mitsubishi Gas Chem Co Inc | Method for feeding iodine |
| CN101659616A (en) * | 2009-09-17 | 2010-03-03 | 河北工业大学 | Technology of preparing diethyl carbonate by urea alcoholysis method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1121659A (en) * | 1995-07-13 | 1996-05-01 | 曾光橦 | Method for realizing exceeding-normal coding |
| JP2001354624A (en) * | 2000-06-12 | 2001-12-25 | Mitsubishi Gas Chem Co Inc | Method for feeding iodine |
| CN101659616A (en) * | 2009-09-17 | 2010-03-03 | 河北工业大学 | Technology of preparing diethyl carbonate by urea alcoholysis method |
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