CN114773188B - Continuous recovery method of methyl cardiac acid raffinate - Google Patents

Abstract

The invention discloses a method for continuous recovery of methyl pyretinate raffinate. The methyl pyretinate raffinate containing isopentenyl pyritinate and methanol are continuously passed through at least one group of catalysts filled with catalysts in series. The fixed-bed reactor is reacted to obtain the methyl peritinate, and the temperature of the first fixed-bed reactor to the last fixed-bed reactor in the plurality of fixed-bed reactors is controlled to decrease sequentially. The invention adopts a programmed cooling method, which can shorten the reaction time and increase the conversion rate of isopentenyl bentinate.

Description

A kind of continuous recovery method of methyl bentinate raffinate

technical field

The invention relates to a method for continuous recovery of methyl bentinate raffinate.

Background technique

The chemical name of methyl pyretinate is 3,3-dimethyl-4-pentenoic acid methyl ester, which is usually prepared by reacting isopentenol with trimethyl orthoacetate. The reaction process involves Claisen rearrangement, and there is a side reaction, and the by-product is prenyl berenate with a high boiling point. During the rectification and purification process of the crude product of methyl perineate, the by-product isopentenyl perinetinate exists in the bottom liquid of the tower bottom.

CN112479872A discloses carrying out the transesterification reaction between the isopentenyl pyretinate and methanol in the rectification raffinate of methyl pyretinate in the presence of the catalyst sodium methoxide, and the temperature is controlled at 70-75°C to obtain a higher mass fraction of However, the reaction is carried out under constant temperature conditions, the reaction time is longer, the conversion rate of isopentenyl perineate is not high enough, and sodium methoxide is a homogeneous catalyst, which is difficult to recycle in the follow-up, and the post-treatment is complicated.

CN1896044A discloses that isopentenyl pyretinate and methanol are reacted at 140° C. for 6 hours in the presence of catalyst sodium methoxide, and the conversion rate of isopentenyl pyritinate is 79.6%, which is relatively low; the patent It is also disclosed that prenyl pyritate and methanol are reacted at 152° C. for 7.5 h in the presence of catalyst tetraisopropyl titanate, and the conversion rate of isopentenyl pyritate is 94.2%, but in Reaction at high temperature may easily cause the color of the product methyl bentinate to change.

Contents of the invention

Aiming at the shortcomings and deficiencies of the prior art, the present invention provides an improved continuous recovery method of methyl pyreneate raffinate, which can shorten the reaction time and increase the conversion rate of isopentenyl pyreneate.

In order to achieve the above object, the technical scheme adopted in the present invention is as follows:

A method for continuous recovery of methyl pyretinate raffinate, the methyl pyretinate raffinate containing isopentenyl pyretinate and methanol are continuously passed through at least one set of fixed-bed reactors filled with catalysts in series Carrying out the reaction to obtain the methyl pyribinate, controlling the temperature from the first fixed-bed reactor to the last fixed-bed reactor in the plurality of fixed-bed reactors to decrease successively.

In some embodiments of the present invention, the temperature of the plurality of fixed-bed reactors is 50-130°C, and the temperature difference between two adjacent fixed-bed reactors is 15-30°C.

In some embodiments of the present invention, the temperature of the first fixed-bed reactor is 100-130° C.; the temperature of the second fixed-bed reactor among the plurality of fixed-bed reactors is 80-100° C. ; The temperature of the third fixed-bed reactor among the plurality of fixed-bed reactors is 50-80°C.

Preferably, the temperature of the first fixed-bed reactor is 100-110°C; the temperature of the second fixed-bed reactor is 80-90°C; the temperature of the third fixed-bed reactor is 60 ~70°C.

In some embodiments of the present invention, the mass percentage of isopentenyl picetinate in the rectification raffinate of methyl pyribinate is 65-70%.

In some embodiments of the present invention, the molar ratio of the isopentenyl pyretinate to methanol is 1:1-10.

In some embodiments of the present invention, the catalyst is selected from one or a combination of solid base catalysts and strongly basic ion exchange resins, and the solid base catalysts are selected from single-component metal oxides and supported One or a combination of two metal oxides.

Preferably, the single-component metal oxide is selected from one or more of CaO, ZnO and Na ₂ O in combination.

Preferably, the supported metal oxide is selected from one or more combinations of CaO supported on TiO ₂ , ZnO supported on ZrO ₂ , Na ₂ O supported on Al ₂ O ₃ and MgO supported on SiO ₂ .

Preferably, the strongly basic ion exchange resin is selected from one or more combinations of AmberLite HPR 900OH, Amberlyst A26OH, AmberLite FPA40 Cl and AmberLite FPA98 Cl.

The volume of the catalyst filling accounts for 1-30% of the volume of the fixed-bed reactor, and the volume percentage of the catalyst loaded in the adjacent fixed-bed reactor is 0-15% lower than that of the adjacent preceding fixed-bed reactor .

In some embodiments of the present invention, the volume of the catalyst packed in the first fixed-bed reactor accounts for 20-25% of the volume of the first fixed-bed reactor.

In some embodiments of the present invention, the volume of the catalyst loaded in the second fixed-bed reactor among the plurality of fixed-bed reactors accounts for 10-20% of the volume of the second fixed-bed reactor.

In some embodiments of the present invention, the volume of the catalyst loaded in the third fixed-bed reactor among the plurality of fixed-bed reactors accounts for 5-10% of the volume of the third fixed-bed reactor.

The raffinate of methyl carditinate refers to the raffinate after separation and purification when synthesizing methyl carditinate. In some embodiments of the present invention, the raffinate of methyl carditinate is the rectification and purification of methyl carditinate after the residue.

In some embodiments of the present invention, the rectification raffinate of methyl pyribinate and methanol are uniformly mixed in a premixer to obtain a raw material mixture, and the raw material mixture is passed into the first fixed bed in the reactor.

In some embodiments of the present invention, a buffer tank is provided between two adjacent fixed-bed reactors among the plurality of fixed-bed reactors.

In some embodiments of the present invention, the continuous recovery method further includes rectification and separation using a rectification tower.

In some embodiments of the present invention, the number of the plurality of fixed bed reactors is 3-7.

Further, the plurality of fixed-bed reactors is 3-5.

Further preferably, there are three fixed-bed reactors.

In the present invention, the isopentenyl pyretinate in the rectification raffinate of methyl pyretinate reacts with methanol to generate methyl pyretinate and prenyl alcohol, and the reaction formula is as follows:

The above-mentioned reaction is an exothermic reversible reaction, and lowering the reaction temperature can make the reversible reaction move to the direction of the forward reaction, thereby increasing the conversion rate of isopentenyl berenate. Lowering the reaction temperature generally lowers the reaction rate. The inventors have found through research that by adopting the programmed cooling method, the reaction is first carried out at a higher temperature, which can make the reaction reach the equilibrium state at this temperature quickly, and then carry out the cooling reaction, so that the reaction continues to reach a lower temperature. Equilibrium conversion rate during the temperature, so can take into account that reaction rate is faster and conversion rate is higher, and then realize that the present invention shortens reaction time, and improves the technical effect of the conversion rate of isopentenyl benzinate.

In some embodiments of the present invention, the continuous recovery method comprises the following steps:

1) the rectification raffinate of methyl pyribinate and methanol are uniformly mixed in a pre-mixer to obtain a raw material mixture, which is passed into the first fixed-bed reactor for reaction to obtain first reaction liquid;

2) passing the first reaction liquid into the second fixed-bed reactor among the plurality of fixed-bed reactors for reaction to obtain a second reaction liquid;

3) passing the second reaction liquid into the third fixed-bed reactor among the plurality of fixed-bed reactors for reaction to obtain a third reaction liquid;

4) Pass the third reaction solution into a rectification tower, and rectify and separate to obtain the methyl pyridate.

Further, the mass space velocity of the raw material mixed liquid is 0.1˜0.2 h ⁻¹ .

Further, the mass space velocity of the first reaction liquid is 0.2˜0.5 h ⁻¹ .

Further, the mass space velocity of the second reaction liquid is 0.2˜0.5 h ⁻¹ .

In some embodiments of the present invention, the mass percentage of isopentenyl picetinate in the third reaction liquid is less than 6%.

Preferably, the mass percentage of isopentenyl picetinate in the third reaction liquid is less than 4%.

In some embodiments of the present invention, the temperature of the first fixed-bed reactor is 100-130°C, and the pressure is 0.35-0.83MPa; the temperature of the second fixed-bed reactor is 80-100°C, and the pressure is 0.20-0.35MPa; the temperature of the third fixed-bed reactor is 50-80°C, and the pressure is 0.10-0.20MPa.

Preferably, the temperature of the first fixed-bed reactor is 100-110°C, and the pressure is 0.35-0.48MPa; the temperature of the second fixed-bed reactor is 80-90°C, and the pressure is 0.20-0.26MPa ; The temperature of the third fixed-bed reactor is 60-70° C., and the pressure is 0.10-0.13 MPa.

The boiling point of the reaction material increases under pressure, which is beneficial to adopt a higher reaction temperature.

After the raw material mixture is passed into the first fixed-bed reactor, it can reach the same temperature of the first fixed-bed reactor quickly; after the first reaction liquid is passed into the second fixed-bed reactor, it can also be relatively The same temperature of the second fixed-bed reactor can be quickly reached; after the second reaction liquid is passed into the third fixed-bed reactor, it can also be quickly reached the same temperature of the third fixed-bed reactor.

In some embodiments of the present invention, in the step 1), the rectification raffinate of methyl picentinate and methanol are uniformly mixed and preheated in a premixer to obtain the raw material mixture, and the preheated The hot temperature is 30-50°C.

The present invention further provides a production method of methyl perinetate, wherein the production method takes isopentenol and trimethyl orthoacetate as raw materials and reacts in the presence of a catalyst to obtain the crude product of methyl perinetate , the crude product of methyl pyridinate is purified to obtain a methyl pyridinate raffinate, and the production method also includes using the continuous recovery method of the aforementioned methyl carditinate raffinate liquid is recovered.

Compared with the prior art, the present invention has the following advantages:

In the present invention, the reaction is carried out under the condition of program cooling, which can realize the improvement of the reaction conversion rate while increasing the reaction rate and shortening the reaction time.

The invention adopts at least one set of fixed-bed reactors connected in series in series, can realize continuous reaction, is suitable for large-scale production, and the heat exchange area of the fixed-bed reactor is large, and the reaction temperature is easy to control.

In the invention, the catalyst is packed in a plurality of fixed-bed reactors, so that the catalyst does not need to be separated, the catalyst recovery cost is reduced, and the catalyst has good stability, and the activity of the catalyst remains basically unchanged after long-term operation.

The temperature of reaction of the present invention can not cause final methyl pyribinate product to change color.

Detailed ways

The present invention will be further described below in conjunction with embodiment. However, the present invention is not limited to the following examples. The implementation conditions adopted in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not indicated are the conventional conditions in this industry. The technical features involved in the various embodiments of the present invention may be combined with each other as long as they do not constitute conflicts with each other.

Example 1

The ZnO catalyzer of ZrO _load is loaded into first fixed-bed reactor, the second fixed-bed reactor, the 3rd fixed-bed reactor respectively, and the filling capacity of catalyst is respectively the total volume of the first fixed-bed reactor 20% of the total volume of the second fixed-bed reactor, 10% of the total volume of the third fixed-bed reactor, and 5% of the total volume of the third fixed-bed reactor.

The rectification raffinate (wherein, the mass fraction of isopentenyl pyridinate is 68%) and methanol are mixed homogeneously in the premixer and preheated to 40 ℃, to obtain a raw material mixture, wherein the molar ratio of isopentenyl bentinate to methanol is 1:5. The raw material mixture is continuously fed into the upper end of the first fixed-bed reactor for reaction to obtain the first reaction liquid. The mass space velocity of the raw material mixture is 0.125h ^-1 , the temperature of the first fixed bed reactor is 110°C, and the pressure is 0.48MPa. The first reaction liquid flows out from the discharge port of the first fixed-bed reactor, passes through the intermediate storage tank, and is continuously fed into the upper end of the second fixed-bed reactor for reaction to obtain the second reaction liquid. The mass space velocity of the first reaction liquid is 0.2h ^-1 , the temperature of the second fixed bed reactor is 90°C, and the pressure is 0.26MPa. The second reaction liquid flows out from the discharge port of the second fixed-bed reactor, passes through the intermediate storage tank, and is continuously fed into the upper end of the third fixed-bed reactor for reaction to obtain the third reaction liquid. The mass space velocity of the second reaction liquid is 0.25h ^-1 , the temperature of the third fixed bed reactor is 60°C, and the pressure is 0.1MPa. The third reaction solution was collected from the outlet of the third fixed-bed reactor, and a sample was taken for GC detection. The mass percentage of isopentenyl picentinate in the third reaction solution was 4.07%, and the reaction ended.

Then the third reaction solution is pumped into the rectification tower, and methyl pyritinate is obtained after rectification and separation. The conversion rate of isopentenyl pyritinate is 90.7%, and the purity of the product methyl pyritinate is 99.81%.

Example 2-8

Embodiment 2-8 is basically the same as embodiment 1, difference is that reaction raw material, catalyst type and loading amount, reaction process parameter are different, specifically as shown in table 1 and table 2 below, wherein, DPE refers to methyl cardylate, MBDP refers to Prenyl bentinate.

Table 1 Example 2-8 Reaction raw materials, catalyst type and loading amount

Table 2 embodiment 2-8 reaction process parameters

In the third reaction solution after the embodiment 2-8 reaction, the mass percent of isopentenyl pyribinate, the conversion rate and the purity of the final methyl pyribinate are shown in Table 3 below:

table 3

Example 9

Continue to run the recovery method in Example 1, the reaction conditions are the same as in Example 1, and the conversion rate and product purity under different operating hours are shown in Table 4 below. It can be seen that the catalyst of the present invention can run stably and continuously for more than 200 hours, and the catalyst activity does not decrease significantly.

Table 4

Running time/h The conversion rate of isopentenyl bentinate/% Purity of Methyl Benetinate/% 10 92.1% 99.81% 50 92.0% 99.81% 100 91.8% 99.80% 200 91.7% 99.82%

Comparative example 1

Basically the same as Example 1, the only difference is that the temperature of the first, second and third fixed bed reactors is 70°C, the mass space velocity of the first reaction solution is 0.125h ^-1 , the second reaction solution The mass space velocity is 0.125h ^-1 . The result is that the mass percentage of isopentenyl pyridinate is 8.75% in the third reaction liquid, and after rectifying tower rectification separates, the conversion rate of isopentenyl pyridinate is 80.7%, and the yield of methyl pyridinate product is The purity is 99.17%. It shows that under constant temperature reaction conditions, even if the reaction time in the second and third fixed-bed reactors is longer, the conversion rate of prenyl pyritate is still reduced.

Comparative example 2

Basically the same as in Example 1, the only difference is that the temperatures of the first, second and third fixed-bed reactors are all 110°C. The result is that the mass percent of isopentenyl pyridinate is 11.51% in the third reaction liquid, and after rectifying tower rectification separates, the transformation rate of isopentenyl pyridinate is 76.7%, and the methyl pyridinate product The purity is 99.23%.

The above-mentioned embodiments are only to illustrate the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly, and not to limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Neither the endpoints nor any values of the ranges disclosed herein are limited to such precise ranges or values, and these ranges or values are understood to include values approaching these ranges or values. For numerical ranges, between the endpoints of each range, between the endpoints of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, these values Ranges should be considered as specifically disclosed herein.

Claims (15)

1. a continuous recovery method of methyl pyritinate raffinate, is characterized in that: the methyl pyretinate raffinate containing isopentenyl pyritinate, methanol are continuously passed through at least one group of sequentially connected The fixed-bed reactor of catalyzer reacts, obtains described methyl perinetate, controls the first fixed-bed reactor in described multiple fixed-bed reactors to the temperature of last fixed-bed reactor to reduce successively; Said The temperature of multiple fixed-bed reactors is 50-130°C, and the temperature difference between two adjacent fixed-bed reactors is 15-30°C; the volume of the catalyst filling accounts for 1-30% of the fixed-bed reactor volume , The volume percentage of the catalyst loaded in the adjacent fixed-bed reactor is 0-15% lower than that in the adjacent preceding fixed-bed reactor. 2. the method for the continuous recovery of methyl bentinate raffinate according to claim 1, is characterized in that: described multiple fixed-bed reactors are 3～7. 3. the method for continuously recovering methyl bentinate raffinate according to claim 1, is characterized in that: described multiple fixed-bed reactors are 3～5. 4. the method for continuous recovery of methyl pyribinate raffinate according to claim 1, is characterized in that: described multiple fixed-bed reactors are 3. 5. the continuous recovery method of methyl perinetate raffinate according to claim 1, is characterized in that: described catalyzer is selected from the combination of one or both in solid base catalyst and strongly basic ion-exchange resin , the solid base catalyst is selected from one or a combination of single-component metal oxides and supported metal oxides. 6. the continuous recovery method of methyl pyribinate raffinate according to claim 5, is characterized in that: described single-component metal oxide is selected from one or more in CaO, ZnO and Na ₂ O and/or, the supported metal oxide is selected from one or more of TiO ₂ loaded CaO, ZrO ₂ loaded ZnO, Al ₂ O ₃ loaded Na ₂ O and SiO ₂ loaded MgO and/or, the strongly basic ion exchange resin is selected from the combination of one or more of AmberLite HPR 900OH, Amberlyst A26OH, AmberLite FPA40 Cl and AmberLite FPA98 Cl. 7. the continuous recovery method of methyl pyrenetate raffinate according to claim 1, is characterized in that: the mass percentage of isopentenyl pyrenetate in the described methyl pyretinate raffinate is 65～70% %; and/or, the molar ratio of the isopentenyl perineate to methanol is 1:1-10. 8. the continuous recovery method of methyl pyribinate raffinate according to claim 1, is characterized in that: described methyl pyribinate raffinate is the raffinate after methyl pyribinate rectification purification; With /or, the methyl pyribinate raffinate and methanol are uniformly mixed in a pre-mixer to obtain a raw material mixture, and the raw material mixture is passed into the first fixed-bed reactor; and/or, A buffer tank is arranged between two adjacent fixed-bed reactors among the plurality of fixed-bed reactors; and/or, the continuous recovery method further includes adopting a rectification tower for rectification and separation. 9. according to the continuous recovery method of the methyl pyribinate raffinate according to any one of claims 1 to 8, it is characterized in that: the continuous recovery method comprises the following steps: 1) Mix the methyl peripinate raffinate and methanol uniformly in a premixer to obtain a raw material mixture, and pass the raw material mixture into the first fixed-bed reactor for reaction to obtain the first a reaction solution; 2) passing the first reaction liquid into the second fixed-bed reactor among the plurality of fixed-bed reactors for reaction to obtain a second reaction liquid; 3) passing the second reaction liquid into the third fixed-bed reactor among the plurality of fixed-bed reactors for reaction to obtain a third reaction liquid; 4) Pass the third reaction solution into a rectification tower, and rectify and separate to obtain the methyl pyridate. 10. the continuous recovery method of methyl peripinate raffinate according to claim 9, is characterized in that: the volume of the catalyzer of packing in the described first fixed-bed reactor accounts for described first fixed-bed reaction 20-25% of the volume of the reactor; and/or, the volume of the catalyst packed in the second fixed-bed reactor among the plurality of fixed-bed reactors accounts for 10-20% of the volume of the second fixed-bed reactor %; and/or, the volume of the catalyst loaded in the third fixed-bed reactor among the multiple fixed-bed reactors accounts for 5-10% of the volume of the third fixed-bed reactor. 11. The method for continuous recovery of methyl bentinate raffinate according to claim 9, characterized in that: the mass space velocity of the raw material mixture is 0.1 to 0.2h ⁻¹ ; and/or, the first The mass space velocity of the first reaction liquid is 0.2-0.5 h ^-1 ; and/or, the mass space velocity of the second reaction liquid is 0.2-0.5 h ^-1 . 12. The continuous recovery method of methyl perineate raffinate according to claim 9, characterized in that: the mass percentage of isopentenyl perinetinate in the third reaction solution is less than 6%. 13. The continuous recovery method of methyl pyribinate raffinate according to claim 9, characterized in that: the mass percentage of isopentenyl pyribinate in the third reaction solution is less than 4%. 14. The method for continuous recovery of methyl bentinate raffinate according to claim 9, characterized in that: the temperature of the first fixed-bed reactor is 100-130° C., and the pressure is 0.35-0.83 MPa; The temperature of the second fixed-bed reactor is 80-100°C and the pressure is 0.20-0.35MPa; the temperature of the third fixed-bed reactor is 50-80°C and the pressure is 0.10-0.20MPa. 15. A production method of methyl pyribinate, said production method takes isopentenol and trimethyl orthoacetate as raw material, reacts in the presence of a catalyst, obtains methyl pyribinate crude product, said The methyl pyritinate crude product obtains the methyl pyretinate raffinate after purification, it is characterized in that: described production method also comprises adopting the continuous recovery of the methyl pyretinate raffinate described in any one of claims 1 to 14 The method recovers the methyl perinetinate raffinate.