CN114426473A - Method for preparing adipic acid by directly oxidizing cyclohexane - Google Patents
Method for preparing adipic acid by directly oxidizing cyclohexane Download PDFInfo
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Abstract
The invention relates to a method for preparing adipic acid by directly oxidizing cyclohexane, which mainly solves the problems of low conversion rate and low selectivity of a cyclohexane direct oxidation method for preparing adipic acid in the prior art, and the method for preparing the adipic acid by directly oxidizing cyclohexane comprises the following steps: 1) mixing oxygen-containing gas 1 with a catalyst, an auxiliary agent and acetic acid to obtain a liquid material 1; 2) the technical scheme of mixing the liquid material 1, cyclohexane and the oxygen-containing gas 2 for reaction to obtain the product mixture containing the adipic acid better solves the technical problem and can be used for the production of preparing the adipic acid by directly oxidizing the cyclohexane.
Description
Technical Field
The invention relates to a method for preparing adipic acid by directly oxidizing cyclohexane.
Background
The reaction mechanism for preparing adipic acid by air-direct oxidation of cyclohexane is generally divided into two steps, the first step, in which cyclohexane is oxidized into cyclohexanone and cyclohexanol under high temperature and pressure conditions by the action of a catalyst and an oxidant, and the second step, in which cyclohexanone and cyclohexanol are continuously oxidized into adipic acid, while side reactions, such as the formation of glutaric acid and succinic acid, and other peroxidation byproducts, occur. These side reactions reduce the selectivity of adipic acid on the one hand, and affect the efficiency of the catalyst on the other hand, leading to premature deactivation of the catalyst, reducing the conversion rate of cyclohexane, and further by-product impurities also add cost and difficulty to the separation of the oxidation reaction solution.
CN109092357A discloses a process for preparing adipic acid by introducing air into cyclohexane and acetic acid in a high-pressure reaction kettle for oxidation under the reaction pressure of 3MPa for 5h to obtain adipic acid, wherein the cyclohexane conversion rate is 54% and the adipic acid selectivity is 85%.
CN104109083A discloses a process for preparing adipic acid by oxidizing cyclohexane with a solvent, a free radical catalyst, a metal catalyst and a cocatalyst, wherein N-hydroxyphthalimide, polyethylene glycol and a cobalt-manganese catalyst are introduced into a high-pressure reaction kettle to react for 5 hours to obtain adipic acid, the cyclohexane conversion rate is 65%, and the adipic acid yield is 30%. The process also has the disadvantages of long reaction time and low overall economy.
CN110128260A discloses a process for oxidizing cyclohexane by directly introducing air into a reaction tower and then switching the cyclohexane into oxygen for continuous oxidation reaction, wherein a gas-liquid tower and a condensation tower are required to be arranged for separating reaction residual gas in the reaction tower, the yield of adipic acid is improved by 3%, the process equipment is complex, gas switching is required according to conditions, the operation is complex, and the reaction effect is not remarkably improved.
Therefore, accurate control of the depth of the cyclohexane oxidation reaction is the key to improving the adipic acid selectivity and the cyclohexane conversion rate. We have found through experimentation that if cyclohexane is directly deoxidized to prepare adipic acid using a low oxygen content gas instead of air, although the oxidation strength can be slowed, the experiments show that the cyclohexane conversion and adipic acid selectivity are not significantly increased. The reason for this analysis is that a simple change in the feed oxygen content deviates from the optimum reaction conditions, whereas a re-optimization of the reaction conditions requires extensive experimental studies and even changes in the reactor configuration. The inventor researches how to improve the efficiency of cyclohexane oxidation under the condition of not changing the reaction temperature, pressure and reactor, and finally finds a method for accurately controlling the oxidation depth.
Disclosure of Invention
The invention aims to solve the technical problems that a cyclohexane direct oxidation method in the prior art is low in cyclohexane conversion rate, low in adipic acid selectivity and difficult to refine more impurities in an oxidation reaction liquid, and provides a novel method for preparing adipic acid by directly oxidizing cyclohexane.
The second technical problem to be solved by the invention is the production device adopted by the method.
In order to solve one of the above technical problems, the technical solution of the present invention is as follows:
a method for preparing adipic acid by directly oxidizing cyclohexane comprises the following steps:
1) mixing oxygen-containing gas 1 with a catalyst, an auxiliary agent and acetic acid to obtain a liquid material 1;
2) the liquid material 1, cyclohexane and oxygen-containing gas 2 are mixed and reacted to obtain a product mixture containing adipic acid.
The conventional method for preparing adipic acid by directly air-oxidizing cyclohexane is to add cyclohexane, acetic acid, a catalyst and an auxiliary agent into a reactor and then directly feed air into the reactor for high-temperature high-pressure oxidation, so that the side reactions are more, the cyclohexane conversion rate is low, and the adipic acid selectivity is not high. However, we have found that the conversion and selectivity of the reaction can be greatly improved by separating cyclohexane from acetic acid, catalyst and auxiliary agent, first mixing the acetic acid solution of catalyst and auxiliary agent with oxygen-containing gas, and then adding oxygen-containing gas and cyclohexane to carry out the cyclohexane oxidation reaction.
In the above technical scheme, in the implementation mode of step 1), preferably, the catalyst, the auxiliary agent and the acetic acid are mixed to obtain an acetic acid solution, and then the oxygen-containing gas 1 is mixed with the acetic acid solution to obtain the liquid material 1.
In the above technical scheme, the mixing temperature in step 1) is preferably 25-65 ℃, such as but not limited to 30 ℃, 35 ℃, 40 ℃, 45 ℃, 50 ℃, 55 ℃ and the like.
In the above technical solution, the mixing pressure in step 1) is preferably 10 to 20MPa, such as but not limited to 11MPa, 12MPa, 13MPa, 14MPa, 15MPa, 16MPa, 17MPa, 18MPa, etc., more preferably 15 to 18 MPa.
In the above technical solution, the volume content of oxygen in the oxygen-containing gas 1 in step 1) and the oxygen-containing gas 2 in step 2) is preferably 10 to 21%, for example, but not limited to, the volume content of oxygen in the oxygen-containing gas 1 in step 1) and the oxygen-containing gas 2 in step 2) is 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 21%, and the like. The oxygen-containing gas 1 is more preferably 15 to 21%, most preferably 18 to 21%. The oxygen-containing gas 2 is more preferably 12 to 16%.
In the technical scheme, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid in the step 1) is preferably 500-2000. For example, but not limited to, the feed volume ratio of oxygen-containing gas 1 to acetic acid in step 1) is 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, etc.
The oxygen-containing gas 1 and the oxygen-containing gas 2 are gases inert to the reaction, such as, but not limited to, nitrogen, helium, argon, etc., except for the given amount of oxygen.
In the above technical scheme, the pressure of the reaction in the step 2) is preferably 1 to 1.5MPa, for example, but not limited to, the pressure of the reaction in the step 2) is 1.1MPa, 1.2MPa, 1.3MPa, 1.4MPa, and the like.
In the above technical scheme, the reaction temperature in step 2) is preferably 85-105 ℃, for example, but not limited to, the reaction temperature in step 2) is 86 ℃, 87 ℃, 88 ℃, 89 ℃, 90 ℃, 91 ℃, 92 ℃, 93 ℃, 94 ℃, 95 ℃, 96 ℃, 97 ℃, 98 ℃, 99 ℃, 100 ℃, 101 ℃, 102 ℃, 103 ℃, 104 ℃ and the like.
In the above technical solution, the volume ratio of the oxygen-containing gas 2 to the cyclohexane in the step 2) is preferably 500 to 2000, for example, but not limited to, the volume ratio of the oxygen-containing gas 2 to the cyclohexane is 600, 700, 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, 1600, 1700, 1800, 1900, and the like.
In the above technical scheme, the step 1) can be mixed in a continuous mode or in a batch mode.
When the step 1) is carried out in a continuous mode, the catalyst and the auxiliary agent are selected to be completely dissolved in acetic acid to obtain an acetic acid solution, and the acetic acid solution is continuously added into the first reactor; an oxygen-containing gas 1 is continuously fed into the first reactor (1). The volume space velocity of the feeding of the acetic acid solution is preferably 0.5-2 hours-1For example, but not limited to, 0.6 hour-10.7 hour-10.8 hour-10.9 hour-11.0 hour-11.1 hour-11.2 hours-11.3 hours-11.4 hours-11.5 hours-11.6 hours-11.7 hours-11.8 hours-11.9 hours-1And so on. And/or preferably the space velocity of the oxygen-containing gas 1 is 800 to 1800 hours-1Such as but not limited to 900 hours-11000 hours, 1-11100 hours, 1-11200 hours-11300 hours, 1300-11400 hours-11500 hours, respectively-11600 hours, 1600 hours-11700 hours-1And so on.
In the above technical scheme, step 2) can be carried out in a continuous mode or in a batch mode.
When step 2) is carried out in a continuous manner, step 2) is carried out in a second reactor, the first reactor liquid feed outlet (4) being fed into the second reactor (6). The volume space velocity of the preferable liquid material 1 is 0.7-3 hours-1For example, but not limited to, 0.8 hour-10.9 hour-11.0 hour-11.1 hour-11.2 hours-11.3 hours-11.4 hours-11.5 hours-11.6 hours-11.7 hours-11.8 hours-11.9 hours -12 hours, 2 hours-12.1 hours-12.2 hours-12.3 hours-12.4 hours-12.5 hours-12.6 hours-12.7 hours-12.8 hours-12.9 hours-1. Preferably, the feeding volume space velocity of the cyclohexane is 0.2-0.8 h-1For example, but not limited to, 0.3 hour-10.4 hour-10.5 hour-10.6 hour-10.7 hour-1And so on. The feeding volume space velocity of the oxygen-containing gas 2 is preferably 1000-1600 hours-1For example, but not limited to, 1100 hours-11200 hours-11300 hours, 1300-11400 hours-11500 hours, respectively-1And so on.
In the above technical solution, the feeding volume air-to-air ratio of the liquid material 1 and cyclohexane in step 2) is preferably 0.5 to 2.5, for example, but not limited to, the feeding volume air-to-air ratio of the liquid material 1 and cyclohexane in step 2) is 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, and the like.
In the above technical solutions, the step 1) and the step 2) are independent and preferably have a stirring operation.
In the above technical scheme, the catalyst is selected from one or more of cobalt, manganese and copper metal salts, and the auxiliary is selected from one or more of cyclohexanone, cyclohexanol, nitroxide free radical (N-hydroxyphthalimide (NHPI for short), N-acetylphthalimide (NAPI for short), N-hydroxysuccinimide (NHS for short), and N-acetylsuccinimide (NAS for short)).
In the above technical scheme, the concentration of cobalt in the acetic acid solution in step 1) is preferably 5-200 mg/L, for example, but not limited to, 25, 50, 75, 100, 125, 150, and 175.
In the above technical scheme, the concentration of manganese in the acetic acid solution in step 1) is preferably 5-200 mg/L, for example, but not limited to, 25, 50, 75, 100, 125, 150, and 175.
In the above technical solution, the concentration of copper in the acetic acid solution in step 1) is preferably 10-400 mg/L, for example, but not limited to, 50, 100, 150, 200, 250, 300, 350.
In the above technical scheme, the concentration of the auxiliary agent in the acetic acid solution in step 1) is preferably 100-5000 mg/L, such as, but not limited to, 500, 1000, 1500, 2000, 2500, 3000, 3500, 4000, 4500.
Defining the gas volume as the gas volume under the standard state (100KPa, 0 ℃); the liquid volume is defined as the liquid volume in the standard state (100KPa, 25 ℃).
The reactor volume space velocity, i.e. the ratio of the volumetric flow of material to the volumetric amount of liquid charged in the reactor, is defined in units of L/(h L), abbreviated to hours-1。
To solve the second technical problem, the technical solution of the present invention is as follows:
the device for preparing adipic acid by direct oxidation of cyclohexane comprises a first reactor (1) and a second reactor (6); the first reactor (1) is provided with an oxygen-containing gas inlet (2), an acetic acid solution feed inlet (10), a first reactor tail gas outlet (3) and a first reactor liquid material outlet (4); the second reactor (6) is provided with an oxygen-containing gas inlet (7), a cyclohexane feed inlet (11), a second reactor tail gas outlet (8) and a second reactor liquid outlet (12); the liquid material outlet (4) of the first reactor is input into the second reactor (6).
In the above technical solution, preferably, the apparatus for preparing adipic acid by direct oxidation of cyclohexane comprises an oxidation reaction liquid collection tank (9).
In the technical scheme, the liquid outlet (12) of the second reactor is preferably input into the oxidation reaction liquid collecting tank (9).
The invention is illustrated by the accompanying drawings and specific examples, which are not intended to limit the scope of the invention to the embodiments.
Drawings
FIG. 1 is a schematic diagram of an apparatus used in the method of the present invention.
In the figure:
1 is a first reactor;
2 is an oxygen-containing gas inlet 1;
3 is a tail gas outlet of the first reactor;
4 is a first reactor liquid material outlet;
6 is a second reactor;
7 is an oxygen-containing gas 2 inlet;
8 is a tail gas outlet of the second reactor;
9 is an oxidation reaction liquid collecting tank;
10 is an acetic acid solution feed inlet;
11 is a cyclohexane feed inlet;
12 is the second reactor liquid outlet.
Detailed Description
[ example 1 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 21% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 50 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the ratio of volume to air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2, the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 15%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after continuous reaction for 2 hours, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis, the cyclohexane conversion rate is 33.25%, and the selectivity of the adipic acid is 97.62%.
[ example 2 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid to obtain an acetic acid solution, feeding the acetic acid solution into a first reactor from an acetic acid solution feed inlet 10 in figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the reaction is performed in a ring mannerThe concentration of hexanone is 2000 mg/L; mixing oxygen-containing gas 1 with 21% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 50 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 10%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after 2 hours of continuous reaction, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis and composition, the cyclohexane conversion rate is calculated to be 30.17%, and the selectivity of the adipic acid is calculated to be 96.44%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 3 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 21% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 50 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 21%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after continuous reaction for 2 hours, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis and composition, the cyclohexane conversion rate is 34.51%, and the adipic acid selectivity is 95.21%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 4 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 15% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 50 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 15 percent, andand (3) discharging the reaction solution from a second reactor tail gas outlet 12 to a synthetic solution collecting tank 9 after the reaction is continuously carried out for 2 hours, sampling adipic acid oxidation reaction solution from the synthetic solution collecting tank, and analyzing the composition, wherein the cyclohexane conversion rate is 32.69% and the adipic acid selectivity is 96.37%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 5 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 21% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 25 ℃, the mixing pressure is 10MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 85 ℃, the oxygen content of the oxygen-containing gas 2 is 15%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after 2 hours of continuous reaction, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis and composition, the cyclohexane conversion rate is 31.43%, and the selectivity of the adipic acid is 96.97%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 6 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 20% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 65 ℃, the mixing pressure is 20MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 105 ℃, the oxygen content of the oxygen-containing gas 2 is 15%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after 2 hours of continuous reaction, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis and composition, the cyclohexane conversion rate is calculated to be 35.28%, and the selectivity of the adipic acid is calculated to be 95.53%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 7 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with oxygen content of 21% with the acetic acid solution from oxygen-containing gas 1 inlet 2 of the first reactor at 50 deg.C under 15MPaThe volume ratio of the acetic acid solution is 1500, wherein the volume space velocity of the acetic acid solution feeding is 1 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1Introducing an oxygen-containing gas 2 from an oxygen-containing gas 2 inlet of the second reactor, wherein the gas volume to cyclohexane volume ratio is 1000, and the volume flow of acetic acid fed into the first reactor is 1 to the cyclohexane fed into the second reactor; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 15%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after 2 hours of continuous reaction, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis, the cyclohexane conversion rate is 27.55%, and the selectivity of the adipic acid is 97.49%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 8 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 21% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 50 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.4 h-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1Oxygen-containing gas2, introducing oxygen-containing gas 2 from a second reactor into the reactor, wherein the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2.5; the reaction pressure of the second reactor is 1.3MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 15%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after 2 hours of continuous reaction, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis and composition, the cyclohexane conversion rate is 36.26%, and the selectivity of the adipic acid is 95.91%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 9 ]
1)1) dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and enabling an obtained acetic acid solution to enter a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 18% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 30 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.0MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 15 percent, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after continuous reaction for 2 hours, the adipic acid is sampled from the synthetic liquid collecting tankThe oxidation reaction solution was analyzed for composition, and the cyclohexane conversion was 35.37% and the adipic acid selectivity was 97.42% were calculated.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
[ example 10 ]
1) Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid, and feeding an obtained acetic acid solution into a first reactor from an acetic acid solution feeding port 10 in the figure 1, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, the concentration of copper in the acetic acid solution is 200mg/L, and the concentration of cyclohexanone in the acetic acid solution is 2000 mg/L; mixing oxygen-containing gas 1 with 21% oxygen content with the acetic acid solution from an oxygen-containing gas 1 inlet 2 of the first reactor, wherein the mixing temperature is 45 ℃, the mixing pressure is 15MPa, the feeding volume ratio of the oxygen-containing gas 1 to the acetic acid solution is 1500, and the volume space velocity of the acetic acid solution feeding is 0.5 hour-1And the mixed liquid material 1 continuously enters the second reactor from a first reactor liquid material outlet 4, and the gas part is discharged from a first reactor tail gas outlet 3.
2) Cyclohexane is continuously added into the second reactor from a cyclohexane feed inlet 11 of the second reactor, and the cyclohexane feeding volume space velocity is 1.0 hour-1The oxygen-containing gas 2 is introduced from an oxygen-containing gas 2 inlet of the second reactor, and the volume ratio of the gas to the cyclohexane is 1000; in the second reactor, the volume-to-air ratio of the feeding of the liquid material 1 to the feeding of cyclohexane is 2; the reaction pressure of the second reactor is 1.5MPa, the reaction temperature is 95 ℃, the oxygen content of the oxygen-containing gas 2 is 15%, the reaction tail gas is discharged from a tail gas outlet of the second reactor, the reaction liquid is discharged from a liquid outlet 12 of the second reactor to a synthetic liquid collecting tank 9, after 2 hours of continuous reaction, the adipic acid oxidation reaction liquid is sampled from the synthetic liquid collecting tank for analysis and composition, the cyclohexane conversion rate is 34.11%, and the selectivity of the adipic acid is 96.75%.
The procedure is as in example 1, and the operating conditions and results are shown in Table 1.
Comparative example 1
Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone in acetic acid to obtain an acetic acid solution, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese in the acetic acid solution is 200mg/L, and the concentration of copper in the acetic acid solution isThe temperature is 200mg/L, the concentration of cyclohexanone is 2000mg/L, oxygen-containing gas with 21 percent of oxygen content is added into a reactor together with acetic acid solution and cyclohexane for reaction, the reaction pressure is 1.3MPa, the reaction temperature is 95 ℃, and the volume space velocity of feeding the acetic acid solution is 2.0 hours-1Cyclohexane feed volume space velocity of 1.0 hour-1And the volume of the oxygen-containing gas is 4000 to the volume of the cyclohexane, after the continuous reaction is carried out for 2 hours, the adipic acid oxidation reaction liquid sampled from the synthetic liquid is taken for analysis to obtain the composition, and the cyclohexane conversion rate is 12.61 percent and the adipic acid selectivity is 74.35 percent.
It is shown that the reaction conversion rate of directly oxidizing cyclohexane with the same volume of oxygen-containing gas is not high (the volume space velocity of the acetic acid solution and cyclohexane is 2: 1. the volume ratio of the total oxygen-containing gas to cyclohexane is 1500 x 2+1000 to 4000, the same applies hereinafter) without mixing acetic acid, catalyst, auxiliary agent and cyclohexane with oxygen-containing gas, the catalyst is deactivated in advance, the side reaction is more, and the selectivity of adipic acid is not high.
Comparative example 2
Dissolving copper acetate, cobalt acetate, manganese acetate and cyclohexanone into acetic acid to obtain an acetic acid solution, wherein the concentration of cobalt in the acetic acid solution is 100mg/L, the concentration of manganese is 200mg/L, the concentration of copper is 200mg/L, the concentration of cyclohexanone is 2000mg/L, oxygen-containing gas with the oxygen content of 15 percent is added into a reactor together with the acetic acid solution and the cyclohexane for reaction, the reaction pressure is 1.3MPa, the reaction temperature is 95 ℃, and the volume space velocity of feeding the acetic acid solution is 2.0 hours-1Cyclohexane feed volume space velocity of 1.0 hour-1And the volume of the oxygen-containing gas is 4000 to the volume of the cyclohexane, after the continuous reaction is carried out for 2 hours, the adipic acid oxidation reaction liquid sampled from the synthetic liquid is taken for analysis to obtain the composition, the cyclohexane conversion rate is 13.29 percent, and the selectivity of the adipic acid is 78.62 percent.
Comparison of comparative example 2 with comparative example 1 shows that the increase in cyclohexane conversion and adipic acid selectivity is insignificant, although the occurrence of side reactions can be reduced to some extent, by merely adjusting the oxygen content in the oxygen-containing gas from 21% to 15% within the experimental range without separately mixing acetic acid, catalyst, promoter and cyclohexane with the oxygen-containing gas.
It should be noted that the above-mentioned embodiments are only for explaining the present invention, and do not constitute any limitation to the present invention. The present invention has been described with reference to exemplary embodiments, but the words which have been used herein are words of description and illustration, rather than words of limitation. The invention can be modified, as prescribed, within the scope of the claims and without departing from the scope and spirit of the invention. Although the invention has been described herein with reference to particular means, materials and embodiments, the invention is not intended to be limited to the particulars disclosed herein, but rather extends to all other methods and applications having the same functionality.
TABLE 1
Claims (9)
1. A method for preparing adipic acid by directly oxidizing cyclohexane comprises the following steps:
1) mixing oxygen-containing gas 1 with a catalyst, an auxiliary agent and acetic acid to obtain a liquid material 1;
2) the liquid material 1, cyclohexane and oxygen-containing gas 2 are mixed and reacted to obtain a product mixture containing adipic acid.
2. The method as set forth in claim 1, wherein the mixing temperature in the step 1) is 25 to 65 ℃.
3. The process according to claim 1, wherein the mixing pressure in step 1) is 10 to 20MPa, preferably 15 to 18 MPa.
4. The method according to claim 1, wherein the oxygen-containing gas 1 in step 1) and the oxygen-containing gas 2 in step 2) independently have an oxygen content of 10 to 21% by volume. The oxygen-containing gas 1 is more preferably 15-21%, most preferably 18-21%; and/or the oxygen-containing gas 2 is preferably 12 to 16%.
5. The method as set forth in claim 1, wherein the feed volume ratio of the oxygen-containing gas 1 to the acetic acid solution in the step 1) is 500 to 2000.
6. The method according to claim 1, wherein the pressure of the reaction in step 2) is 1 to 1.5 MPa. And/or the reaction temperature in the step 2) is 85-105 ℃.
7. The process as claimed in claim 1, wherein the volume ratio of oxygen-containing gas 2 to cyclohexane in step 2) is from 500 to 2000.
8. The method as set forth in claim 1, wherein the feed volume air-to-space ratio of the liquid material 1 to cyclohexane in the step 2) is 0.5 to 2.5.
9. The device for preparing adipic acid by direct oxidation of cyclohexane comprises a first reactor (1) and a second reactor (6); the first reactor (1) is provided with an oxygen-containing gas inlet (2), an acetic acid solution feed inlet (10), a first reactor tail gas outlet (3) and a first reactor liquid material outlet (4); the second reactor (6) is provided with an oxygen-containing gas inlet (7), a cyclohexane feed inlet (11), a second reactor tail gas outlet (8) and a second reactor liquid outlet (12); the liquid material outlet (4) of the first reactor is input into the second reactor (6).
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5547905A (en) * | 1994-07-27 | 1996-08-20 | Council Of Scientific & Industrial Research | Catalyst and a process for preparing carboxylic acids using the catalyst |
| WO2001000555A1 (en) * | 1999-06-25 | 2001-01-04 | Chemintel (India) Private Limited | A process for preparation of adipic acid |
| KR20160056210A (en) * | 2014-11-11 | 2016-05-19 | 롯데케미칼 주식회사 | Catalytic oxidation of cyclic ketone |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5547905A (en) * | 1994-07-27 | 1996-08-20 | Council Of Scientific & Industrial Research | Catalyst and a process for preparing carboxylic acids using the catalyst |
| WO2001000555A1 (en) * | 1999-06-25 | 2001-01-04 | Chemintel (India) Private Limited | A process for preparation of adipic acid |
| KR20160056210A (en) * | 2014-11-11 | 2016-05-19 | 롯데케미칼 주식회사 | Catalytic oxidation of cyclic ketone |
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