CN113053463A - Modeling method of dynamic model of aromatic oxidation reaction and dynamic model - Google Patents
Modeling method of dynamic model of aromatic oxidation reaction and dynamic model Download PDFInfo
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- 239000007800 oxidant agent Substances 0.000 claims description 8
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- 238000013461 design Methods 0.000 abstract description 4
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- 230000003647 oxidation Effects 0.000 description 28
- GPSDUZXPYCFOSQ-UHFFFAOYSA-N m-toluic acid Chemical compound CC1=CC=CC(C(O)=O)=C1 GPSDUZXPYCFOSQ-UHFFFAOYSA-N 0.000 description 20
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Abstract
The invention relates to a modeling method and a kinetic model of an aromatic oxidation reaction kinetic model, wherein the modeling method comprises the following steps: in the process of preparing IPA or PTA by adopting MX or PX, a chain initiation reaction rate constant k is obtained by experimental fitting1 fit(ii) a Will k1 fitSubstituted into the kinetic model as k1Searching the minimum value of the function S by using an lsqnolin function, and calculating model parameters alpha and beta; substituting the calculated model parameters alpha and beta and different catalyst concentrations under actual production conditions into the kinetic model, and calculating to obtain the chain initiation reaction rate constant k in actual production1 cal. The dynamic model established by the invention can quantitatively describe the influence of the concentration and the proportion of the catalyst on the oxidation reaction process at the industrial temperature and the solvent ratio, and guide the design of an industrial reactor, the optimization of production operation conditions and production engineeringAnd (4) optimizing the process.
Description
Technical Field
The invention relates to a model modeling method and a corresponding model in a chemical production process, in particular to a dynamic model modeling method and a dynamic model for aromatic hydrocarbon oxidation reaction.
Background
Isophthalic Acid (IPA) and terephthalic Acid (PTA) are fast-developing organic chemical intermediate raw materials. Terephthalic acid is used primarily as a monomer in PET polyester feedstocks. The isophthalic acid is mainly used as a modified monomer of the PET resin to improve the processing and product performance of the PET resin; the method is used for replacing phthalic anhydride to produce high-strength chemical-corrosion-resistant unsaturated resin; replace phthalic anhydride to produce alkyd resin with high performance and high solid content. IPA has been widely used abroad, and its development prospect is promising, and many large companies are preparing to expand the production capacity and build new IPA apparatuses. With the continuous expansion of the device scale, the cost of the device is continuously reduced, and the application field and the market share are continuously expanded. The application of IPA in China has a certain foundation, and IPA is applied to the fields of bottle-grade polyester resin, polyester cation dyeable fiber, unsaturated resin and alkyd resin high-grade paint at present, but the source of IPA is mainly solved by import. As many large foreign companies expand their production capacity using advanced technology and create new IPA devices, the competitiveness of these devices will be a major problem. The reaction process is fully known, and the establishment of a kinetic model of the reaction process has extremely important significance for guiding the production of the isophthalic acid and the terephthalic acid, and the competitiveness of enterprises can be improved.
In industrial production, PX/MX oxidation reaction follows a radical chain oxidation mechanism, and many intermediate products exist in the reaction, for example, p- (m) -methylbenzaldehyde (hereinafter, referred to as p (m) -TALD), p- (m) -methylbenzoic acid (hereinafter, referred to as p (m) -TA), p- (m) -carboxybenzaldehyde (hereinafter, referred to as 4(3) -CBA), and the like. It is generally believed that the two methyl groups of PX/MX are oxidized sequentially to alcohol, aldehyde, acid in the oxidation process, and the whole process is a serial, irreversible process:
in the prior art, although the catalytic reaction mechanism in the PX/MX oxidation process has been simplified to some extent, the PX/MX oxidation reaction still comprises 30 reaction steps. In a PX/MX oxidation reaction system, the concentrations of only 5 main components (PX, p-TALD, p-TA, 4-CBA, PTA and MX, m-TALD, m-TA, 3-CBA and IPA) can be accurately obtained by sampling and liquid chromatography analysis. Since the free base generated during the reaction is unstable, the concentration of the free radicals is difficult to detect quantitatively. Estimating 30 model parameters with 5 observed variables, the estimated parameters are unreliable due to large randomness, which is called overfitting, and therefore it is necessary to further reduce the model parameters to avoid overfitting. At present, many scholars establish a reaction kinetic model, and the model can well reflect the change of reactant concentration along with time and can predict the influence of reaction temperature on the reaction. However, the influence of the concentration and the proportion of the catalyst on the reaction is very complex, and no suitable model for reflecting and predicting the influence of the concentration and the proportion of the catalyst on the reaction exists so far, so that the optimization of an industrial reactor, production operation conditions and a production process is limited.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides a dynamic model modeling method and a dynamic model for aromatic hydrocarbon oxidation reaction, which can quantitatively describe the influence of catalyst concentration and proportion on the oxidation reaction process.
The technical scheme for realizing the aim of the invention is as follows: the modeling method of the dynamic model of the aromatic oxidation reaction comprises the following steps:
s1: in the process of preparing IPA or PTA by adopting MX or PX, a chain initiation reaction rate constant k1 is obtained by experimental fittingfit(kinetic reaction rate constant without added catalyst concentration);
s2: will k1 fitSubstituted into the following formula as k1And searches for the minimum value of the function S using the lsqnolin function, calculates model parameters alpha and beta,
when MX is used, the formula used is:
when PX is used, the formula used is:
wherein [ Co ]]、[Mn]And [ Br]Relative concentrations of cobalt catalyst, manganese catalyst and bromine promoter, k, respectively, in the catalyst1Is the chain initiation reaction rate constant (min-1);
s3: the calculated model parameters alpha and beta and the [ Co ] different under the actual production condition]、[Mn]And [ Br]Substituting the concentration into the formula (1) or (2), and calculating to obtain the chain initiation reaction rate constant k in actual production1 cal。
Due to the difference in reactivity of the alkyl groups on PX and MX, PX reacts 1.69 times faster than MX. Therefore, when fitting a PX oxidation chain initiation reaction rate constant model, only alpha and beta need to be obtained from the MX oxidation system, and k of MX is calculated1Calculated value (k)1 cal) Multiplying by 1.69 to obtain the chain initiation reaction rate constant k of PX oxidation under the same reaction condition and operation1Calculated value (k)1 cal) I.e. the same reaction conditions and operation, k of PX1 calK of 1.69 × MX1 cal。
The lsqnolin function can be an lsqnolin function conventional in the art, preferably an lsqnolin function in MATLAB, and has the formula:
wherein k is1,i calAnd k1,i fitRespectively, the chain initiation reaction rate constants determined by the formula and experimental fitting, m is the total number of experiments, and the ordinal numbers i are 1 to m.
Preferably, in the S1, k is obtained by experimental fitting1 fitFor the obtained k calculated by the following formula1：
When the aromatic hydrocarbon is MX, the formula is adopted as follows:
C＝(k2CMX+k3Cm-TALD+k4Cm-TA+k5C3-CBA) (15)
wherein [ O ]]MX、[O]m-TALD、[O]m-TA、[O]3-CBAAre peroxy radicals derived from MX, m-TALD, m-TA, 3-CBA, respectively, Ci-O4-jWherein i and j independently represent an alkyl group or an acyl group;
when the aromatic hydrocarbon is PX, respectively replacing MX, m-TALD (m-tolualdehyde), m-TA (m-toluic acid), 3-CBA (3-carboxybenzaldehyde), and IPA in formulas (4) - (15) with PX, p-TALD, p-TA, 4-CBA, and PTA;
c independently represents a molar mass ratio concentration (mol/kg) of the corresponding component in the reaction system, for example, the concentration of the substance MX is Cm-MXm-TALD concentration of Cm-TALDm-TA concentration of Cm-TA3-CBA concentration of C3-CBAIPA concentration of CIPAThe concentration of PX is CPXp-TALD concentration of Cp-TALDp-TA concentration of Cp-TAThe concentration of 4-CBA is C4-CBAPTA concentration of CPTA；
dC/dt represents the reaction rate [ mol/(min. kg) ]each step]And k1 denotes the chain initiation reaction rate constant (min)-1)，k2-5Represents the chain transfer reaction rate constant [ kg/(mol. min) ]]，k6Represents a chain termination reaction rate constant [ kg2/(mol2·min)]。
Further, the reaction rate constant k1-k6Obtained by reducing the sum of squared residuals by the following formula:
wherein m is the total number of experiments, i is 1 to m, i is the number of experiments, j is 1 to 5, is a component MX, m-TALD, m-TA, 3-CBA and IPA, or is a component PX, p-TALD, p-TA, 4-CBA and PTA,
and
respectively, the calculated value and the measured value of the jth component concentration. In the calculation, the concentrations C of the respective components are respectively substituted into those of the formula (16)
And (4) finishing.
Preferably, in the preparation of IPA or PTA, the solvent is a mixture of acetic acid and water, the catalyst is a ternary composite Co-Mn-Br catalyst, and the oxidant is air, in the solvent, under the catalytic action of the catalyst, MX (m-xylene) or PX (p-xylene) and the oxidant undergo the following catalytic oxidation reaction:
the mass ratio of the cobalt catalyst to the manganese catalyst in the catalyst is 1:2-2:1 (e.g., 1:2, 1:1 or 2:1), and/or the mass ratio of the sum of the cobalt catalyst and the manganese catalyst to the bromine promoter is 1:2-3:1 (e.g., 1:2, 1:1.5, 1:1, 3:2, 2:1 or 3:1), and/or the mass ratio concentration of the bromine promoter in the reaction system is 350-1800ppm (e.g., 350ppm, 400ppm, 600ppm, 700ppm, 800ppm, 1200ppm, 1400ppm or 1800 ppm).
The concentrations (ppm) and proportions of the cobalt catalyst, the manganese catalyst and the bromine promoter can be 800/400/1200, 1200/600/1800, 400/800/1200, 400/400/1200, 800/400/400, 350/700/700, 700/350/700 and 350/350/1400.
Preferably, the concentration of water in the solvent is 1% to 15% by mass, such as 1%, 2%, 5%, 8%, 10%, 12% or 15%.
Further, the concentration of water in the reaction system is 6% to 8% by mass, for example, 6%, 7% or 8%, preferably 8%.
Preferably, the mass ratio of MX or PX to the solvent is from 1:5 to 1:3, such as 1:5, 1:4 or 1: 3.
Preferably, the reaction temperature for preparing IPA or PTA is 448.2-466.2K, such as 448.2K, 450.2K, 453.15K, 456.2K, 458.2K, 463.2K, 465K or 466.2K, preferably 453.15K (180 ℃), and the reaction pressure is 1.1-1.3MPa, such as 1.1MPa, 1.2MPa or 1.3MPa (the reaction pressure is maintained at a vapor pressure, and when the reaction pressure is greater than the critical value, the reaction pressure has no effect on the oxidation reaction, and when the reaction pressure is less than the critical value, the reaction pressure has an effect on the oxidation reaction).
Preferably, the flow rate of the oxidant in the production of IPA or PTA is 10-12L/min, such as 10L/min, 11L/min or 12L/min, preferably 12L/min. There is a critical value for the oxygen concentration in the reaction, above which there is no effect on the oxidation reaction, only below which there is an effect on the oxidation reaction. Therefore, the air flow rate ensures that the oxygen concentration is greater than the critical value, and the consumption of the reaction is met, namely the influence of the oxygen concentration is eliminated.
The catalytic oxidation of MX or PX can be carried out in a reaction vessel conventional in the art for such reactions, such as a semi-continuous reaction vessel. The stirring speed of the reaction vessel during the reaction can be a speed conventional in this type of reaction in the art, for example, 800 rpm.
The kinetic model of any aromatic hydrocarbon oxidation reaction disclosed by the invention can be obtained by adopting the kinetic model modeling method of any aromatic hydrocarbon oxidation reaction disclosed by the invention.
A kinetic model of the oxidation reaction of aromatic hydrocarbons,
when the aromatic hydrocarbon is MX, the model formula is as follows:
when the aromatic hydrocarbon is PX, the model formula is:
wherein [ Co ]]、[Mn]And [ Br]Relative concentrations of cobalt catalyst, manganese catalyst and bromine promoter, k, respectively, in the catalyst1Is the chain initiation reaction rate constant (min)-1) And α and β are model parameters.
Preferably, the model parameters α and β are obtained by fitting experiments to obtain chain initiation reaction rate constants, and the chain initiation reaction rate constants are substituted into the model formula as k1And is calculated by searching for the minimum of the function S using the lsqnolin function of
Wherein k is1,i calAnd k1,i fitRespectively, the chain initiation reaction rate constants determined by the model formula and experimental fitting, m is the total number of experiments, and the ordinal number i is 1 to m.
The kinetic model may be applied using procedures conventionally used in the art, for example, using the chain-initiated reaction rate constant k1 obtained by the modeling methodcalPerforming kinetic model calculation, specifically, obtaining kinetic parameters by laboratory experiment, and obtaining kinetic parameters by obtained motionMechanical parameters allow for different size commercial reactor designs (e.g., reactor design parameters of 80 cubic, 100 cubic, etc.) giving operating conditions (suitable temperature, catalyst concentration, etc.) for different terephthalic or isophthalic acid yield conditions.
The invention has the beneficial effects that: the dynamic model established by the invention can quantitatively describe the influence of the concentration and the proportion of the catalyst on the oxidation reaction process under the industrial temperature and the solvent ratio, guide the design of an industrial reactor, the optimization of production operation conditions and the optimization of a production process, solve the problem that the free radical dynamic model is difficult to describe the influence of catalyst factors on the oxidation reaction in the prior art, improve the advancement of the oxidation reaction dynamic model in the prior art and have great guiding significance on the industrial MX/PX liquid phase oxidation process. The modeling method is suitable for establishing liquid phase oxidation kinetic models of different alkyl aromatic hydrocarbons and has wide applicability.
Drawings
FIG. 1 is a graph comparing experimental values with calculated values of MX oxidation reactant and product concentrations at a Co/Mn/Br concentration (ppm) of the catalyst of 800/400/1200 in example 1 of the present invention;
FIG. 2 is a graph comparing experimental values with calculated values of PX oxidation reactant and product concentrations under the condition that the catalyst Co/Mn/Br concentration (ppm) is 350/700/700 in example 2 of the present invention;
FIG. 3 is a graph comparing experimental values with calculated values of PX oxidation reactant and product concentrations under the condition that the catalyst Co/Mn/Br concentration (ppm) is 700/350/700 in example 2 of the present invention;
FIG. 4 is a graph comparing experimental values with calculated values of PX oxidation reactant and product concentrations under the condition that the catalyst Co/Mn/Br concentration (ppm) in example 2 of the present invention is 350/350/1400.
Detailed Description
Example 1:
(1) acquisition of Experimental data
The method is characterized in that a Co-Mn-Br ternary complex system serving as a catalyst is adopted in the high-temperature catalytic oxidation process of industrial m-xylene (MX), acetic acid-water (mixture of acetic acid and water) serving as a solvent and air serving as an oxidant are carried out in a semi-continuous stirring bubbling kettle under the conditions that the reaction temperature is 180 ℃ (453.15K) and the reaction pressure is 1.2 Mpa.
The catalyst mixture ratio is shown in table 1, the air flow rate is 12L/min, the material MX and the solvent (acetic acid-water) are 1:5 (mass ratio), and the stirring speed of the reaction kettle is 800 rpm. The mass percent concentration of water is 8%, the mass percent concentration of MX is 1/6 × 100%, and the mass percent concentration of acetic acid is (1-8% -1/6 × 100%).
The experiment is a batch reaction process, and the reaction time is 20 min. MX, m-TALD, m-TA, 3-CBA and IPA concentrations were obtained by sampling at different times (1min, 3min, 5min, 7min, 12min, 15min and 20min) during the experiment. For example, fig. 1 shows the experimental results under the conditions of 453.15K, [ Co ]/[ Mn ]/[ Br ] ═ 800/400/1200 ppm. Where the points represent concentration experimental values and the lines represent concentration fitted values, the other concentration data are similar.
TABLE 1 Experimental reaction conditions for MX catalytic Oxidation Process
| Batches of | Temperature (K) | Reactants | H2O concentration (% by mass) | Co/Mn/Br concentration (ppm) |
| 1 | 453.15 | MX | 8 | 400/400/1200 |
| 2 | 453.15 | MX | 8 | 400/800/1200 |
| 3 | 453.15 | MX | 8 | 1200/600/1800 |
| 4 | 453.15 | MX | 8 | 500/250/750 |
| 5 | 453.15 | MX | 8 | 800/600/1200 |
| 6 | 453.15 | MX | 8 | 800/400/1200 |
(2) Dynamic model construction
The differential equation of the change of the concentration of each component and the corresponding component free radical with the reaction time in the semi-continuous reaction experiment is shown in the formulas (4) to (13):
wherein:
C＝(k2CMX+k3Cm-TALD+k4Cm-TA+k5C3-CBA) (15)
concentration values of inlet materials of all components:
t＝0,CMX＝CO MX,Cm-TALD＝0,Cm-TA＝0,C3-CBA＝0,CIPA＝0,
in the above formula, CiDenotes the concentration (mol/kg), dC, of the corresponding componentiThe reaction rates of the respective steps [ mol/(min. kg)]，k1Represents the rate constant (min) of the chain initiation reaction-1)，k2-5Represents the chain transfer reaction rate constant [ kg/(mol. min) ]]，k6Represents a chain termination reaction rate constant [ kg2/(mol2·min)]。
(3) Determining the kinetic parameters of each step of reaction, and selecting a target function
Carrying out parameter fitting on the acquired experimental data by using a kinetic model based on free radical chain reaction, wherein the reaction rate constant k1-k6Is obtained by reducing the sum of squared residuals by the following equation:
wherein the content of the first and second substances,
respectively represents the calculated value and the experimental value of a certain component, 1-5 respectively represents MX, m-TALD, m-TA, 3-CBA and IPA, and m represents the total experiment times.
From the obtained concentration data, calculation by the above fittingObtained k1-k6As shown in table 2.
TABLE 2 Rate constant fitting values for MX catalytic oxidation process with corresponding confidence interval Table (confidence 95%)
Thus, the parameters that can be shared, i.e., k, are listed in Table 22To k is6And only k1As the only variable parameter. As can be seen from table 1, all confidence intervals are at least 1 order of magnitude smaller than the corresponding rate constants, indicating that the rate constants are deterministic and reliable. Furthermore, the chain propagation step proceeds faster than the chain initiation and termination steps, which is characteristic of typical free radical chain reactions. In particular, the rate constant of the chain initiation step is 10-5Orders of magnitude, more sensitive to temperature variations. Clearly there is very good agreement between the experimental data and the model calculations from reactants to intermediates to the main product.
(4) Model including catalyst influencing factor, and parameter calculation
The model formula is as follows:
wherein, the [ Co ], [ Mn ] and [ Br ] respectively represent the relative concentration of each element in the Co-Mn-Br catalyst.
The initiation rate constant k between the calculated value and the experimental fitting value is calculated by the least square method1The sum of squared differences of (a) is minimized. The function used is as follows:
wherein k is1,i calAnd k1,i fitRespectively representing the chain initiation rate constants determined by a model formula and a fitting experiment; m-8 (representing experiment)Total number of times). And the lsqnolin function (equation (3)) in MATLAB is used to search for the minimum value of the function S.
The final values of α and β were calculated to be 0.0022 and 0.0003, respectively.
(5) Authentication
A comparison of the chain initiation rate constants for MX oxidation between the calculation method (model equation) and the fitting experiment is shown in table 3:
TABLE 3 comparison of the chain initiation rate constants for MX oxidation obtained using different methods
Model parameters: α is 0.0022 and β is 0.0003.
Temperature: 453.15K.
It can be shown that the model formula and the modeling method thereof predict the experiment k of MX catalytic oxidation1The fitting value of (1).
Example 2:
(1) acquisition of Experimental data
The high-temperature catalytic oxidation process of industrial Paraxylene (PX) adopts a Co-Mn-Br ternary complex system as an oxidant, and takes acetic acid-water (mixture of acetic acid and water) as a solvent and air as the oxidant in a semi-continuous stirring bubbling kettle under the conditions of a reaction temperature of 180 ℃ (453.15K) and a reaction pressure of 1.1MPa-1.3 MPa.
The catalyst mixture ratio is shown in table 4, the air flow rate is 12L/min, the material raw material PX and the solvent (acetic acid-water) are 1:5 (mass ratio), and the stirring speed of the reaction kettle is 800 rpm. The mass percent concentration of water is 8%, the mass percent concentration of PX is 1/6 × 100%, and the mass percent concentration of acetic acid is (1-8% -1/6 × 100%).
The experiment is a batch reaction process, and the reaction time is 20 min. In the experimental process, PX, p-TALD, p-TA, 4-CBA and PTA concentrations are obtained by sampling at different times (1min, 3min, 5min, 7min, 12min, 15min and 20 min).
TABLE 4 Experimental reaction conditions Table for PX catalytic Oxidation Process
| Batches of | Temperature (K) | Reactants | H2O concentration (% by mass) | Co/Mn/Br concentration (ppm) |
| 1 | 453.15 | PX | 8 | 700/350/700 |
| 2 | 453.15 | PX | 8 | 350/700/700 |
| 3 | 453.15 | PX | 8 | 350/350/1400 |
(2) Constructing a dynamic model, determining dynamic parameters of each step of reaction, and selecting a target function
Experimental procedure for PX Components MX, m-TA in formulas (4) to (15) and (17) in example 1Replacing LD, m-TA, 3-CBA and IPA with PX, p-TALD, p-TA, 4-CBA and PTA, and making reaction rate constant k1-k6Obtained by calculation of formula (16).
K calculated from the obtained concentration data by the above fitting1-k6As shown in table 5.
TABLE 5 Rate constant fitting values for PX catalytic oxidation process with corresponding confidence interval Table (confidence 95%)
(3) Model including catalyst influencing factor, and parameter calculation
Wherein, the [ Co ], [ Mn ] and [ Br ] respectively represent the relative concentration of each element in the Co-Mn-Br catalyst.
The initiation rate constant k between the calculated value and the experimentally fitted value was determined by the least squares method using the formula (3) in example 11The sum of squared differences of (a) is minimized.
The final values of α and β were calculated to be 0.0022 and 0.0003, respectively.
(4) Authentication
Due to the difference in reactivity of the alkyl groups on PX and MX, PX reacts 1.69 times faster than MX. Therefore, when fitting a PX oxidation chain initiation constant model, only alpha and beta are obtained from a MX oxidation system and multiplied by 1.69, so that the chain initiation rate constant k of PX oxidation can be estimated1。
As shown in table 6, the model predicted values and the experimental fitted values have very good consistency, and the α and β values of MX oxidation process can be successfully applied to PX oxidation process. The accuracy and transferability of the kinetic model of the invention are verified.
TABLE 6 comparison of the chain initiation rate constants for PX oxidation obtained using different methods
Model parameters: α is 0.0022 and β is 0.0003.
Temperature: 453.15K.
Referring to fig. 2-4, the PX liquid phase oxidation process also has good fitting accuracy, further illustrating the adaptability of the constructed kinetic model, and the established kinetic model containing the catalyst concentration can well predict the influence of the catalyst concentration and the proportion on the reaction, and can effectively guide and optimize the industrial production process.
Claims (10)
1. A modeling method of a kinetic model of aromatic hydrocarbon oxidation reaction is characterized by comprising the following steps:
s1: in the process of preparing IPA or PTA by adopting MX or PX, a chain initiation reaction rate constant k is obtained by experimental fitting1 fit；
S2: will k1 fitSubstituted into the following formula as k1And searches for the minimum value of the function S using the lsqnolin function, calculates model parameters alpha and beta,
when MX is used, the formula used is:
when PX is used, the formula used is:
wherein [ Co ]]、[Mn]And [ Br]Relative concentrations of cobalt catalyst, manganese catalyst and bromine promoter, k, respectively, in the catalyst1Is a chainAn initiation reaction rate constant;
s3: the calculated model parameters alpha and beta and the [ Co ] different under the actual production condition]、[Mn]And [ Br]Substituting the concentration into the formula, and calculating to obtain the chain initiation reaction rate constant k in actual production1 cal。
2. The method of modeling a kinetic model of an aromatic oxidation reaction as set forth in claim 1 wherein said lsqnolin function is
Wherein k is1,i calAnd k1,i fitRespectively, the chain initiation reaction rate constant determined by the formula and experimental fitting, and m is the total number of experiments.
3. The method for modeling a kinetic model of an aromatic oxidation reaction according to claim 1 or 2, wherein when IPA or PTA is prepared, the solvent is a mixture of acetic acid and water, the catalyst is a Co-Mn-Br three-component composite catalyst, the oxidant is air, the mass ratio of the cobalt catalyst to the manganese catalyst in the catalyst is 1:2-2:1, and/or the mass ratio of the sum of the mass of the cobalt catalyst and the mass of the manganese catalyst to the mass of the bromine promoter is 1:2-3:1, and/or the mass ratio concentration of the bromine promoter in the reaction system is 350-.
4. The method of modeling a kinetic model of an aromatic oxidation reaction as set forth in claim 3, wherein the concentration of water in said solvent is between 1% and 15% by mass.
5. The method for modeling a kinetic model of an oxidation reaction of aromatic hydrocarbons according to claim 4 wherein the concentration of water in the reaction system is 6% to 8% by mass.
6. The method of modeling a kinetic model of an aromatic oxidation reaction as set forth in claim 3, wherein the mass ratio of MX or PX to said solvent is from 1:5 to 1: 3.
7. The method of claim 3, wherein the reaction temperature is 448.2-466.2K and the reaction pressure is 1.1-1.3MPa when IPA or PTA is prepared.
8. The method of claim 3, wherein the flow rate of the oxidizing agent during the production of IPA or PTA is 10-12L/min.
9. A kinetic model of aromatic oxidation reaction is characterized in that
When the aromatic hydrocarbon is MX, the model formula is as follows:
when the aromatic hydrocarbon is PX, the model formula is:
wherein [ Co ]]、[Mn]And [ Br]Relative concentrations of cobalt catalyst, manganese catalyst and bromine promoter, k, respectively, in the catalyst1For the chain-initiated reaction rate constants, α and β are model parameters.
10. A kinetic model of an oxidation reaction of aromatic hydrocarbons as claimed in claim 9, characterized in that the model parameters α and β are substituted into the model formula as k by fitting experiments to obtain chain initiation reaction rate constants1And is calculated by searching for the minimum of the function S using the lsqnolin function of
Wherein k is1,i calAnd k1,i fitAre respectively disclosed by the modelEquation and the rate constant of chain initiation reaction determined by experimental fitting, m being the total number of experiments.
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| US4354037A (en) * | 1978-03-07 | 1982-10-12 | Teijin Limited | Process for preparing benzenecarboxylic acids |
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| US4354037A (en) * | 1978-03-07 | 1982-10-12 | Teijin Limited | Process for preparing benzenecarboxylic acids |
| CN1417192A (en) * | 2002-12-10 | 2003-05-14 | 扬子石油化工股份有限公司 | Establishing method of dynamic model of liquid phase catalytic paraxylene oxidizing reaction |
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