Method for preparing dibutyl phthalate synthesis catalyst through temperature programming
The method of preparing polyacid catalysts through program heating has solved the problems of low catalytic yield and serious corrosion in the existing DBP synthesis methods, and achieved efficient and environmentally friendly DBP synthesis, improving yield and product quality.
Patent Information
- Application Number
- CN202411576885.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-06
- Publication Date
- 2025-02-14
AI Technical Summary
The existing DBP synthesis methods have problems such as low catalytic yield, serious corrosion and three waste pollution.
The method of preparing a polyacid catalyst is adopted by procedural heating. Through thermal analysis and dynamic atmosphere heating, the product with the best thermal decomposition effect is selected as the catalyst, and the catalyst is used during the synthesis process.
It significantly improves the yield of DBP, reduces the generation of corrosive by-products, reduces equipment maintenance costs and environmental pollution, and improves product quality and market competitiveness.
Smart Images
Figure CN119425748A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of catalyst processing, in particular to a method for preparing a dibutyl phthalate synthesis catalyst by programmed temperature increase. Background Art
[0002] Dibutyl phthalate (DBP) is a good plasticizer, and its usage and output rank first among plasticizers. DBP has the advantages of light color, low toxicity, good electrical properties, low volatility, low temperature resistance and low odor. It is widely used in polyvinyl chloride processing, which can make the products have good softness; for nitrocellulose coatings, DBP has excellent stability and softening effect, and also has good flex resistance, adhesion and waterproof properties. In addition, DBP can also be used as a plasticizer for alkyd resins, vinyl acetate, chloroprene rubber and ethyl cellulose, and is used in the manufacture of paints, artificial fibers, adhesives, printing inks, dyes, celluloid, safety glass and other products.
[0003] With the rapid development of my country's economy, DBP, as a commonly used plasticizer, has been widely studied and made some progress under the background of rapid development of science and technology and increasing environmental awareness. At present, the commonly used DBP synthesis method in China is to esterify phthalic anhydride and n-butanol under the action of sulfuric acid. Although sulfuric acid is cheap, the process is mature and the product yield is high, this method is prone to side reactions, serious corrosion, three wastes pollution and difficult to control product quality.
[0004] Therefore, the present invention proposes a method for preparing a dibutyl phthalate synthesis catalyst by programmed temperature to solve the deficiencies of the prior art. Summary of the invention
[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing a dibutyl phthalate synthesis catalyst by programmed temperature increase, aiming to solve the problems of low catalytic yield and severe corrosion of the existing catalyst in the process of catalyzing the preparation of dibutyl phthalate, and provides a method for preparing a polyacid catalyst for catalyzing dibutyl phthalate by programmed temperature increase with simple and rapid operation, thereby improving the traditional preparation method.
[0006] To achieve the above object, the present invention is implemented by the following technical scheme: A method for preparing a polyacid catalyst by programmed temperature increase, characterized in that it comprises the following steps:
[0007] S1. Conduct thermal analysis on phosphotungstic acid, phosphomolybdic acid and silicotungstic acid respectively;
[0008] S2. In a dynamic atmosphere, heating phosphotungstic acid, phosphomolybdic acid and silicotungstic acid in a temperature range of 25°C to 1000°C at a heating rate of 5°C / min to 20°C / min;
[0009] S3. Select the product with the best thermal decomposition effect as the catalyst at different heating rates.
[0010] Preferably, the phosphotungstic acid, phosphomolybdic acid and silicotungstic acid are ground using an agate mortar before the experiment.
[0011] Preferably, the dynamic atmosphere is an air atmosphere.
[0012] Preferably, the S3 step includes:
[0013] a) collecting the thermal decomposition products at each heating rate;
[0014] b) evaluating the catalytic performance of each thermal decomposition product, wherein the evaluation criteria include but are not limited to activity test and selectivity test;
[0015] c) Based on the catalytic performance evaluation results, the product with the highest catalytic activity and / or selectivity is selected as the final catalyst.
[0016] The invention also provides a polyacid catalyst used in the synthesis of dibutyl phthalate, and the catalyst is prepared by the preparation method.
[0017] Preferably, the catalyst is a thermal decomposition product of phosphotungstic acid, phosphomolybdic acid or silicotungstic acid.
[0018] The present invention also provides a method for synthesizing dibutyl phthalate using the catalyst, comprising the following steps:
[0019] 1) mixing phthalic anhydride, n-butanol and benzene with the catalyst;
[0020] 2) heating and stirring the reaction mixture at a temperature range of 70° C. to 120° C. until solid phthalic anhydride disappears;
[0021] 3) Raise the temperature to 90°C-130°C and reflux for several hours until the reaction is complete.
[0022] Preferably, the heating step comprises gradually increasing the temperature to 85°C to 95°C and maintaining the temperature therein for about 5 to 15 minutes.
[0023] Preferably, the reflux time is 2 to 4 hours.
[0024] Preferably, the method further comprises washing the crude product with a 4% to 6% sodium carbonate aqueous solution, then washing the organic layer with a saturated saline solution, and finally drying with anhydrous magnesium sulfate until clear.
[0025] The invention provides a method for preparing a dibutyl phthalate synthesis catalyst by programmed temperature increase.
[0026] It has the following beneficial effects:
[0027] 1. The method provided by the present invention is reasonably designed, the entire preparation process is simple and clear, and does not require complicated operation steps or expensive equipment, which is suitable for large-scale industrial production. The experimental operation is easy to master, which significantly reduces the technical threshold and is convenient for factory promotion and application.
[0028] 2. The present invention effectively controls the thermal decomposition process and the catalytic reaction by means of programmed temperature increase, and the reaction time is significantly shortened. The long reaction time in the traditional method is greatly compressed, the production efficiency is improved, and the demand for high efficiency and speed in industrial production is met.
[0029] 3. The polyacid catalyst prepared by the present invention has a higher catalytic performance than the traditional catalyst after optimization treatment. Specifically, under the same conditions, it can significantly improve the yield of dibutyl phthalate. The experimental results show that the catalyst prepared by the method of the present invention exhibits excellent catalytic activity and stability under various reaction conditions.
[0030] 4. Sulfuric acid is often used as a catalyst in traditional methods. Although it can achieve a higher yield, it will produce corrosive byproducts, causing serious corrosion damage to production equipment. The method of the present invention effectively reduces the generation of corrosive byproducts by using a polyacid catalyst, prolongs the service life of the equipment, and reduces maintenance costs.
[0031] 5. The method of the present invention reduces the generation of three wastes in the traditional method, including waste liquid, waste gas and waste residue, and significantly reduces the pollution to the environment. The entire reaction process complies with the principles of green chemistry, reduces the emission of harmful substances, is more environmentally friendly, and helps enterprises achieve sustainable development goals.
[0032] 6. Due to the advantages of simple operation, rapid reaction and reduced equipment corrosion, the method of the present invention reduces production costs while improving the market competitiveness of the product. The high-yield and high-quality dibutyl phthalate product meets the high-standard requirements of the market and brings significant economic benefits to the enterprise. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 The present invention is a flow chart of the method for preparing dibutyl phthalate synthesis catalyst by programmed temperature. DETAILED DESCRIPTION
[0034] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0035] Embodiment 1:
[0036] Please refer to the attached Figure 1 :
[0037] The experimental item phosphotungstic acid (H3[P(W3O10)4]·XH2O) was subjected to thermal analysis. The sample was carefully ground with an agate mortar before the experiment to make the sample uniform. The sample was placed in an Al2O3 crucible using a DTG-60 synchronous thermal analyzer (Mettler-Toledo Instruments, Switzerland) and the thermal analysis experiment was carried out under a dynamic atmosphere with a gas flow rate of 20 ml / min and air as the selected gas. The measured temperature range was 25-1000°C, and the heating rates were 20°C / min, 15°C / min, 10°C / min, and 5°C / min, respectively. The products at different heating rates were obtained, and the product with the best thermal decomposition effect was selected as the catalyst.
[0038] The process of evaluating and selecting the optimal heating rate is as follows:
[0039] Thermal decomposition product collection: After completing the thermal analysis at each heating rate, the respective thermal decomposition products were collected.
[0040] Catalytic performance evaluation:
[0041] Activity test: Each thermal decomposition product is subjected to a standardized catalytic activity test to determine the rate at which it catalyzes a reaction under specific conditions.
[0042] Selectivity test: Evaluate the product selectivity of each thermal decomposition product when catalyzing a specific reaction, that is, the ratio of the target product to the by-product.
[0043] According to the results of the activity test and the selectivity test, the products at each heating rate are comprehensively evaluated. The thermal decomposition products at the heating rate that exhibit the highest catalytic activity and / or the best selectivity are selected. In this embodiment, the thermal decomposition products of phosphotungstic acid obtained at a heating rate of 10°C / min exhibit the best catalytic performance, so the products at this heating rate are selected as the final catalyst.
[0044] In a three-necked flask, add excess n-butanol (6mg) and phthalic anhydride (4mg), benzene (5.5ml) and thermally decomposed phosphotungstic acid (P2O5+WO3) catalyst (0.3mg), and then add a few zeolites, and fill the water separator with n-butanol. First heat at a temperature below 100℃ and start the stirrer. After about 9 minutes, the temperature rises to about 90℃, and all the solid phthalic anhydride disappears, that is, the alcoholysis reaction of phthalic anhydride is over. Control the temperature at 110℃ and reflux for 3 hours until no water drops evaporate, and the reaction is over.
[0045] After the reactants are cooled, the crude product is transferred to a separatory funnel and washed with a 5% sodium carbonate aqueous solution to remove the catalyst and trace amounts of unreacted phthalic anhydride. The organic layer is then washed with saturated brine, the water layer is separated, and then dried with anhydrous magnesium sulfate until the organic layer is clear, and the clear liquid is taken. The solvent is first evaporated under normal pressure, and then distilled under reduced pressure to obtain a colorless liquid, which is the product dibutyl phthalate. The mass of the product is 5.385 g, and the yield is 71.6%.
[0046] Embodiment 2:
[0047] The experimental item phosphomolybdic acid (24MoO3·P2O5·3H2O) was subjected to thermal analysis. The sample was carefully ground with an agate mortar before the experiment to make the sample uniform. The sample was placed in an Al2O3 crucible using a DTG-60 synchronous thermal analyzer (Mettler-Toledo Instruments, Switzerland) and the thermal analysis experiment was carried out under a dynamic atmosphere with a gas flow rate of 20 ml / min and air as the selected gas. The measured temperature range was 25-1000°C, and the heating rates were 20°C / min, 15°C / min, 10°C / min, and 5°C / min, respectively. The products at different heating rates were obtained, and the product with the best thermal decomposition effect was selected as the catalyst.
[0048] The process of evaluating and selecting the optimal heating rate is as follows:
[0049] Thermal decomposition product collection: After completing the thermal analysis at each heating rate, the respective thermal decomposition products were collected.
[0050] Catalytic performance evaluation:
[0051] Activity test: Each thermal decomposition product is subjected to a standardized catalytic activity test to determine the rate at which it catalyzes a reaction under specific conditions.
[0052] Selectivity test: Evaluate the product selectivity of each thermal decomposition product when catalyzing a specific reaction, that is, the ratio of the target product to the by-product.
[0053] According to the results of the activity test and the selectivity test, the products at each heating rate are comprehensively evaluated. The thermal decomposition products at the heating rate that exhibit the highest catalytic activity and / or the best selectivity are selected. The thermal decomposition products of phosphomolybdic acid obtained at a heating rate of 15°C / min in this embodiment exhibit the best catalytic performance, so the products at this heating rate are selected as the final catalyst.
[0054] In a three-necked flask, add excess n-butanol (6mg) and phthalic anhydride (4mg), benzene (5.5ml) and thermally decomposed phosphomolybdic acid (MoO3+H3PO4) catalyst (0.3mg), and then add a few zeolites, and fill the water separator with n-butanol. First heat at a temperature below 100℃ and start the stirrer. After about 9 minutes, the temperature rises to about 90℃, and all the solid phthalic anhydride disappears, that is, the alcoholysis reaction of phthalic anhydride is over. Control the temperature at 110℃ and reflux for 3 hours until no water drops evaporate, and the reaction is over.
[0055] After the reactants are cooled, the crude product is transferred to a separatory funnel and washed with a 5% sodium carbonate aqueous solution to remove the catalyst and trace amounts of unreacted phthalic anhydride. The organic layer is then washed with saturated brine, the water layer is separated, and then dried with anhydrous magnesium sulfate until the organic layer is clear, and the clear liquid is taken. The solvent is first evaporated under normal pressure, and then distilled under reduced pressure to obtain a colorless liquid, which is the product dibutyl phthalate. The mass of the product is 4.1 g, and the yield is 54.5%.
[0056] Embodiment 3:
[0057] The experimental item silicotungstic acid (H4[Si(W3O10)4]·xH2O) was subjected to thermal analysis. The sample was carefully ground with an agate mortar before the experiment to make the sample uniform. The sample was placed in an Al2O3 crucible using a DTG-60 synchronous thermal analyzer (Mettler-Toledo Instruments, Switzerland) and thermal analysis experiments were performed under a dynamic atmosphere with a gas flow rate of 20 ml / min and air as the selected gas. The measured temperature range was 25-1000°C, and the heating rates were 20°C / min, 15°C / min, 10°C / min, and 5°C / min, respectively. The products at different heating rates were obtained, and the product with the best thermal decomposition effect was selected as the catalyst.
[0058] The process of evaluating and selecting the optimal heating rate is as follows:
[0059] Thermal decomposition product collection: After completing the thermal analysis at each heating rate, the respective thermal decomposition products were collected.
[0060] Catalytic performance evaluation:
[0061] Activity test: Each thermal decomposition product is subjected to a standardized catalytic activity test to determine the rate at which it catalyzes a reaction under specific conditions.
[0062] Selectivity test: Evaluate the product selectivity of each thermal decomposition product when catalyzing a specific reaction, that is, the ratio of the target product to the by-product.
[0063] Data analysis and decision making:
[0064] According to the results of the activity test and the selectivity test, the products at each heating rate are comprehensively evaluated. The thermal decomposition products at the heating rate that exhibit the highest catalytic activity and / or the best selectivity are selected. In this embodiment, the thermal decomposition products of silicotungstic acid obtained at a heating rate of 10°C / min exhibit the best catalytic performance, so the products at this heating rate are selected as the final catalyst.
[0065] In a three-necked flask, add excess n-butanol (6mg) and phthalic anhydride (4mg), benzene (5.5ml) and thermally decomposed silicotungstic acid (SiO2+4WO3) catalyst (0.3mg), and then add a few zeolites, and fill the water separator with n-butanol. First heat at a temperature below 100℃ and start the stirrer. After about 9 minutes, the temperature rises to about 90℃, and all the solid phthalic anhydride disappears, that is, the alcoholysis reaction of phthalic anhydride is over. Control the temperature at 110℃ and reflux for 3 hours until no water drops evaporate, and the reaction is over.
[0066] After the reactants are cooled, the crude product is transferred to a separatory funnel and washed with a 5% sodium carbonate aqueous solution to remove the catalyst and trace amounts of unreacted phthalic anhydride. The organic layer is then washed with saturated brine, the water layer is separated, and then dried with anhydrous magnesium sulfate until the organic layer is clear, and the clear liquid is taken. The solvent is first evaporated under normal pressure, and then distilled under reduced pressure to obtain a colorless liquid, which is the product dibutyl phthalate. The mass of the product is 5.189 g, and the yield is 69%.
[0067] Comparative Example 1:
[0068] In a three-necked flask, add excess n-butanol (6 mg), phthalic anhydride (4 mg), benzene (5.5 ml) and phosphotungstic acid (H3[P(W3O10)4]·XH2O) catalyst, and then add a few zeolites. The water separator is filled with n-butanol. First, heat at a temperature below 100°C and start the stirrer. After about 9 minutes, the temperature rises to about 90°C, and all the solid phthalic anhydride disappears, which means that the alcoholysis reaction of phthalic anhydride is over. Control the temperature at 110°C and reflux for 3 hours until no water drops evaporate, and the reaction is over.
[0069] After the reactants are cooled, the crude product is transferred to a separatory funnel and washed with a 5% sodium carbonate aqueous solution to remove the catalyst and trace amounts of unreacted phthalic anhydride. The organic layer is then washed with saturated brine, the water layer is separated, and then dried with anhydrous magnesium sulfate until the organic layer is clear, and the clear liquid is taken. The solvent is first evaporated under normal pressure, and then distilled under reduced pressure to obtain a colorless liquid, which is the product dibutyl phthalate. The mass of the product is weighed to be 3.077g, and the yield is 40.9%.
[0070] Comparative Example 2:
[0071] In a three-necked flask, add excess n-butanol (6 mg), phthalic anhydride (4 mg), benzene (5.5 ml), phosphomolybdic acid (24MoO3·P2O5·3H2O) catalyst, and then add a few zeolites. The water separator is filled with n-butanol. First, heat at a temperature below 100°C and start the stirrer. After about 9 minutes, the temperature rises to about 90°C, and all the solid phthalic anhydride disappears, which means that the alcoholysis reaction of phthalic anhydride is over. Control the temperature at 110°C and reflux for 3 hours until no water drops evaporate, and the reaction is over.
[0072] After the reactants are cooled, the crude product is transferred to a separatory funnel and washed with a 5% sodium carbonate aqueous solution to remove the catalyst and trace amounts of unreacted phthalic anhydride. The organic layer is then washed with saturated brine, the water layer is separated, and then dried with anhydrous magnesium sulfate until the organic layer is clear, and the clear liquid is taken. The solvent is first evaporated under normal pressure, and then distilled under reduced pressure to obtain a colorless liquid, which is the product dibutyl phthalate. The mass of the product is weighed to be 2.937g, and the yield is 39%.
[0073] Comparative Example 3:
[0074] In a three-necked flask, add excess n-butanol (6 mg), phthalic anhydride (4 mg), benzene (5.5 ml), silicotungstic acid (H4[Si(W3O 10 )4]·xH2O) raw material catalyst, and then add a few zeolites, and fill the water separator with n-butanol. First heat it at a temperature below 100°C and start the stirrer. After about 9 minutes, the temperature rises to about 90°C, and all the solid phthalic anhydride disappears, that is, the phthalic anhydride alcoholysis reaction is over. Control the temperature at 110°C and reflux for 3 hours until no water drops evaporate, and the reaction is over.
[0075] After the reactants are cooled, the crude product is transferred to a separatory funnel and washed with a 5% sodium carbonate aqueous solution to remove the catalyst and trace amounts of unreacted phthalic anhydride. The organic layer is then washed with saturated brine, the water layer is separated, and then dried with anhydrous magnesium sulfate until the organic layer is clear, and the clear liquid is taken. The solvent is first evaporated under normal pressure, and then distilled under reduced pressure to obtain a colorless liquid, which is the product dibutyl phthalate. The mass of the product is weighed to be 2.378g, and its yield is 31.6%.
[0076] Comparison of experimental results:
[0077] Under the same conditions and the same dosage, the effect of catalyst on product yield is shown in the following table:
[0078] Table 1:
[0079] catalyst Phosphotungstic acid (original sample) Phosphotungstic acid (after thermal decomposition) Yield (mg) 3.077 5.385 Yield (%) 40.9 71.6
[0080] Table 2:
[0081] catalyst Silicotungstic acid (original sample) Silicotungstic acid (after thermal decomposition) Yield (mg) 2.378 5.189 Yield (%) 31.6 69
[0082] Table 3:
[0083] catalyst Phosphomolybdic acid (original sample) Phosphomolybdic acid (after thermal decomposition) Yield (mg) 2.937 4.1 Yield (%) 39 54.5
[0084] It can be seen from the above table that the polyacid catalyst for catalyzing dibutyl phthalate prepared by the present invention has higher catalytic performance than the original sample. Among the different samples, the catalytic performance of phosphotungstic acid is better than that of phosphomolybdic acid and silicotungstic acid.
[0085] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a polyacid catalyst by programmed temperature, characterized in that: The following steps are involved: S1. Conduct thermal analysis on phosphotungstic acid, phosphomolybdic acid and silicotungstic acid respectively; S2. In a dynamic atmosphere, heating phosphotungstic acid, phosphomolybdic acid and silicotungstic acid in a temperature range of 25°C to 1000°C at a heating rate of 5°C / min to 20°C / min; S3. Select the product with the best thermal decomposition effect as the catalyst at different heating rates.
2. The method for preparing a polyacid catalyst by programmed temperature increase according to claim 1, characterized in that: The phosphotungstic acid, phosphomolybdic acid and silicotungstic acid were ground using an agate mortar before the experiment.
3. The method for preparing a polyacid catalyst by programmed temperature increase according to claim 1, characterized in that: The dynamic atmosphere is an air atmosphere.
4. The method for preparing a polyacid catalyst by programmed temperature increase according to claim 1, characterized in that: The S3 step includes: a) collecting the thermal decomposition products at each heating rate; b) evaluating the catalytic performance of each thermal decomposition product, wherein the evaluation criteria include but are not limited to activity test and selectivity test; c) Based on the catalytic performance evaluation results, the product with the highest catalytic activity and / or selectivity is selected as the final catalyst.
5. A polyacid catalyst used in the synthesis of dibutyl phthalate, characterized in that: The catalyst is prepared by the method according to any one of claims 1 to 4.
6. The polyacid catalyst used in the synthesis of dibutyl phthalate according to claim 5, characterized in that The catalyst is a thermal decomposition product of phosphotungstic acid, phosphomolybdic acid or silicotungstic acid.
7. A method for synthesizing dibutyl phthalate using the catalyst according to claim 5 or 6, characterized in that: The following steps are involved: 1) mixing phthalic anhydride, n-butanol and benzene with the catalyst; 2) heating and stirring the reaction mixture at a temperature range of 70° C. to 120° C. until solid phthalic anhydride disappears; 3) Raise the temperature to 90°C-130°C and reflux for several hours until the reaction is complete.
8. The method according to claim 7, characterized in that The heating step includes gradually increasing the temperature to 85° C. to 95° C. and maintaining the temperature for about 5 to 15 minutes.
9. The method according to claim 7, characterized in that: The reflux time is 2 to 4 hours.
10. The method according to claim 7, characterized in that The method further comprises washing the crude product with a 4% to 6% sodium carbonate aqueous solution, then washing the organic layer with a saturated saline solution, and finally drying with anhydrous magnesium sulfate to clarify.