Industrial preparation method of methyl nadic anhydride

Abstract

The invention relates to an industrial preparation method of methyl nadic anhydride, which comprises the following steps: (1) feeding a solvent into an addition reaction kettle, mixing the solvent with maleic anhydride and an isomerization catalyst which are added through a spiral feeder, and then feeding methyl cyclopentadiene into the addition reaction kettle for addition reaction; (2) feeding the material after the addition reaction from the middle lower part of a filter, filtering out unreacted maleic anhydride and an isomerization catalyst from the bottom, feeding the material at the top of the filter into a desolventizing tower, returning a solvent obtained at the tower top to the addition reaction kettle, and obtaining crude methyl nadic anhydride at the tower bottom; and (3) feeding the methyl nadic anhydride into a refining tower, extracting by-products from the tower top, and obtaining the methyl nadic anhydride from the tower bottom. The method is simple to operate, low in cost, low in requirements on used equipment and suitable for large-scale production, and the purity of the obtained methyl nadic anhydride is greater than 99%.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of epoxy resin, and particularly relates to an industrialized preparation method of methyl nadic anhydride. BACKGROUND

[0002] Methyl nadic anhydride is an excellent anhydride type epoxy resin curing agent, which has the characteristics of low curing exothermicity, small curing volume shrinkage, light color of resin after curing, small moisture absorption and excellent arc resistance, and is widely used in electrical insulation materials, especially large electrical appliances. At present, there are few reports on methyl nadic anhydride in China, and the demand for methyl nadic anhydride depends on imports. The methyl nadic anhydride will have a broad development prospect in the domestic market in the future. Its reaction formula is as follows:

[0003] .

[0004] CN101165060A discloses a method for modifying methyl nadic anhydride, which is modified into heat-resistant and toughened methyl nadic anhydride by using heat-resistant anhydride, toughening agent and catalyst. The method only mentions the method for modifying methyl nadic anhydride. JP6032788A discloses a synthesis method of methyl nadic anhydride, and the methyl nadic anhydride product obtained by the above method has low purity. SUMMARY

[0005] The technical problem to be solved by the present application is to provide an industrialized preparation method of methyl nadic anhydride, which has the advantages of simple operation, low cost, low requirement for equipment and suitability for large-scale production, and the purity of the obtained methyl nadic anhydride is greater than 99%.

[0006] The present application provides an industrialized preparation method of methyl nadic anhydride, which comprises the following steps:

[0007] (1) the solvent is fed into an addition reaction kettle and mixed with maleic anhydride and isomerization catalyst added through a screw feeder, and then methylcyclopentadiene is fed into the addition reaction kettle for addition reaction;

[0008] (2) the material after the addition reaction is fed from the middle and lower parts of a filter, the unreacted maleic anhydride and isomerization catalyst are filtered out from the bottom, and the material at the top of the filter is fed into a desolventizing tower, the solvent obtained at the top of the tower is returned to the addition reaction kettle, and the crude methyl nadic anhydride is obtained at the bottom of the tower;

[0009] (3) the crude methyl nadic anhydride is fed into a refining tower, the by-product is collected at the top of the tower, and the methyl nadic anhydride is obtained at the bottom of the tower.

[0010] Preferably, in step (1), the solvent is 50-60 parts by weight, maleic anhydride is 20-25 parts, methylcyclopentadiene is 20-25 parts, and isomerization catalyst is 5-15 parts.

[0011] Preferably, the solvent is one or more of benzene, toluene, and xylene.

[0012] Preferably, the isomerization catalyst is Raney nickel.

[0013] Preferably, the addition reaction process parameters in step (1) are: reaction temperature of 55~70℃, residence time of 0.5~2.5h, and system pressure of 0.02~0.2MPa. More preferably, the reaction temperature is 55~60℃ and the residence time is 1.0~1.5h.

[0014] Preferably, the parameters of the solvent removal column in step (2) are: the temperature at the top of the column is 30~60℃, the temperature at the bottom of the column is 80~130℃, the system pressure is 7.50~18.40KPa, and the reflux ratio is 1~4. More preferably, the temperature at the top of the column is 40~50℃, the temperature at the bottom of the column is 90~110℃, the system pressure is 7.50~10.00KPa, and the reflux ratio is 1~2.

[0015] Preferably, the purification column parameters in step (2) are: a temperature at the top of the column of 80~110℃, a temperature at the bottom of the column of 100~130℃, a system pressure of 7.50~18.40KPa, and a reflux ratio of 1~4. More preferably, the temperature at the top of the column of 90~100℃, the temperature at the bottom of the column of 100~110℃, the system pressure of 7.50~10.00KPa, and the reflux ratio of 3~4.

[0016] This invention involves adding methylcyclopentadiene, produced by the cleavage of methylcyclopentadiene dimer, to a solvent and reacting it with maleic anhydride in the presence of an isomerization catalyst to produce methylnadic anhydride. Using solvents such as benzene, toluene, or xylene for dilution of the addition reaction reduces the self-dimerization of methylcyclopentadiene during the reaction, thus increasing the product yield. Using Raney nickel as the isomerization catalyst significantly improves the selectivity of the methylnadic anhydride addition reaction, maximizing the addition of methylcyclopentadiene to maleic anhydride and increasing the product yield to over 95%.

[0017] This invention recovers the isomerization catalyst and unreacted maleic anhydride by filtering them through a filter, which can improve the utilization rate of raw materials, save costs, and reduce the generation of by-products.

[0018] This invention uses a two-stage purification process for methylnadic anhydride. The solvent is removed and recovered in a solvent removal tower for reuse. The purification tower removes byproducts produced during the addition reaction (such as methylcyclopentadiene dimer). Through this purification method, the purity of methylnadic anhydride is greater than 99%.

[0019] Beneficial effects

[0020] This invention is simple to operate, low in cost, and requires minimal equipment, making it suitable for large-scale production. The resulting methylnadic anhydride has a selectivity greater than 98%, a yield greater than 95%, and a purity greater than 99%. Attached Figure Description

[0021] Figure 1 This is a flowchart of the apparatus and process of the present invention;

[0022] X1 is a screw feeder, R1 is an addition reactor (with agitator and jacket), R2 is a filter, E1, E3, and E4 are coolers, E2 and E5 are reboilers, T1 is a solvent removal tower, T2 is a purification tower, P1, P2, P3, P4, and P5 are material transfer pumps; F1~F10 are the materials involved in this invention: F1 is solvent, F2 is methylcyclopentadiene, F3 is maleic anhydride, F4 isomerization catalyst, F5 is unreacted maleic anhydride and recovered isomerization catalyst, F6 is crude methyl nadic anhydride with solvent remaining after addition, F7 is recovered solvent, F8 is crude methyl nadic anhydride after solvent removal, F9 is high-purity methyl nadic anhydride product, and F10 is the removed by-product (methylcyclopentadiene dimer, etc.); V1 and V2 are receiving tanks. Detailed Implementation

[0023] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0024] The process flow of each embodiment is attached. Figure 1 As shown.

[0025] Example 1

[0026] 17.32 kg toluene, 8.66 kg maleic anhydride, and 1.732 kg Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg methylcyclopentadiene was added. The reaction temperature was 55 °C, and the reaction was carried out for 1 hour with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, entered the desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 kPa. a. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is detected by gas chromatography. The results are shown in Table 1.

[0027] Example 2

[0028] 17.32 kg of toluene, 8.66 kg of maleic anhydride, and 1.732 kg of Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg of methylcyclopentadiene was added. The reaction temperature was 60 °C, and the reaction was carried out for 1 hour with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, entered the desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 kPa. a. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is detected by gas chromatography. The results are shown in Table 1.

[0029] Example 3

[0030] 17.32 kg toluene, 8.66 kg maleic anhydride, and 1.732 kg Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg of methylcyclopentadiene was added. The reaction temperature was 65 °C, and the reaction was carried out for 1 hour with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, entered the desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 kPa. a. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is detected by gas chromatography. The results are shown in Table 1.

[0031] Example 4

[0032] 17.32 kg toluene, 8.66 kg maleic anhydride, and 1.732 kg Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg methylcyclopentadiene was added. The reaction temperature was 70 °C, and the reaction was carried out for 1 hour with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, entered the desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 kPa. a. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is detected by gas chromatography. The results are shown in Table 1.

[0033] Example 5

[0034] 17.32 kg toluene, 8.66 kg maleic anhydride, and 1.732 kg Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg methylcyclopentadiene was added. The reaction temperature was 55 °C, and the reaction was carried out for 0.5 h with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, entered the desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 K. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is determined by gas chromatography. The results are shown in Table 1.

[0035] Example 6

[0036] 17.32 kg toluene, 8.66 kg maleic anhydride, and 1.732 kg Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg methylcyclopentadiene was added. The reaction temperature was 55 °C, and the reaction was carried out for 1.5 h with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, entered the desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 K. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is determined by gas chromatography. The results are shown in Table 1.

[0037] Example 7

[0038] 17.32 kg toluene, 8.66 kg maleic anhydride, and 1.732 kg Raney nickel (maleic anhydride and Raney nickel were added via screw feeder X1) were added to a 50 L addition reactor R1. The mixture was heated until the maleic anhydride was completely dissolved, and then 6.928 kg methylcyclopentadiene was added. The reaction temperature was 55 °C, and the reaction was carried out for 2 hours with stirring. The resulting material was cooled to below 50 °C via cooler E1 and filtered through filter R2 to remove unreacted maleic anhydride and recovered Raney nickel F5. The crude methylnadic anhydride F6, still containing solvent after addition, obtained from the top of the filter, was fed into a desolventizing tower T1. The top temperature of the desolventizing tower was 40 °C, the temperature of the tower bottom was 100 °C, and the system pressure was 7.50 kPa. a. The reflux ratio is 1. The toluene obtained from the top of the column is cooled by cooler E3 and returned to the addition reactor R1. The bottom material of column T1 is returned to the desolventizing column T1 through reboiler E2. The crude methylnadic anhydride F8 from the bottom of the column enters the purification column T2. ​​The top temperature of the purification column is 90°C, the bottom temperature is 120°C, the system pressure is 7.50 kPa, and the reflux ratio is 4. The by-product (methylcyclopentadiene dimer, etc.) F10, which has been cooled by cooler E4, is collected from the top of the column. The bottom material of column T2 is returned to the purification column T2 through reboiler E5. High-purity methylnadic anhydride F9 is obtained from the bottom of the column. The purity of the collected methylnadic anhydride is detected by gas chromatography. The results are shown in Table 1.

[0039] Table 1 Results of each embodiment

[0040]

[0041] Note:

[0042] 1. MNA selectivity refers to the percentage of added methylcyclopentadiene that is converted into methylnadic anhydride.

[0043] 2. MNA yield refers to the percentage of the final methylnadic anhydride product obtained relative to the sum of the added methylcyclopentadiene and the reacted maleic anhydride.

[0044] 3. MNA purity refers to the amount of MNA in the product.

Claims

1. An industrial-scale preparation method for methylnadic anhydride, characterized in that, Includes the following steps: (1) The solvent is fed into the addition reactor and mixed with maleic anhydride and isomerization catalyst added through a screw feeder. Then, methylcyclopentadiene is fed into the addition reactor to carry out the addition reaction. (2) The material after the above addition reaction is fed from the middle and lower part of the filter. The unreacted maleic anhydride and isomerization catalyst are filtered out from the bottom. The material at the top of the filter is sent to the desolventizing tower. The solvent obtained at the top of the tower is returned to the addition reaction vessel. Crude methyl nadic anhydride is obtained at the bottom of the tower. (3) The above crude methyl nadic anhydride is fed into a refining column, the by-product is collected at the top of the column, and methyl nadic anhydride is obtained at the bottom of the column.

2. The preparation method according to claim 1, characterized in that: In step (1), by weight, the solvent is 50-60 parts, maleic anhydride is 20-25 parts, methylcyclopentadiene is 20-25 parts, and isomerization catalyst is 5-15 parts.

3. The preparation method according to claim 1 or 2, characterized in that: The solvent is one or more of benzene, toluene, and xylene.

4. The preparation method according to claim 1 or 2, characterized in that: The isomerization catalyst is Raney nickel.

5. The preparation method according to claim 1, characterized in that: The addition reaction process parameters in step (1) are: reaction temperature of 55~70℃, residence time of 0.5~2.5h, and system pressure of 0.02~0.2MPa.

6. The preparation method according to claim 1, characterized in that: The parameters of the solvent removal tower in step (2) are as follows: the temperature at the top of the tower is 30~60℃, the temperature at the bottom of the tower is 80~130℃, the system pressure is 7.50~18.40KPa, and the reflux ratio is 1~4.

7. The preparation method according to claim 1, characterized in that: The parameters of the refining column in step (2) are: the temperature at the top of the column is 80~110℃, the temperature at the bottom of the column is 100~130℃, the system pressure is 7.50~18.40KPa, and the reflux ratio is 1~4.

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