CN1245171A - Process for preparing sym-phenyltetraformic dianhydride - Google Patents
Process for preparing sym-phenyltetraformic dianhydride Download PDFInfo
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- CN1245171A CN1245171A CN 98116910 CN98116910A CN1245171A CN 1245171 A CN1245171 A CN 1245171A CN 98116910 CN98116910 CN 98116910 CN 98116910 A CN98116910 A CN 98116910A CN 1245171 A CN1245171 A CN 1245171A
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- acid anhydride
- pyromellitic acid
- catalyzer
- carrier
- production method
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- Heterocyclic Carbon Compounds Containing A Hetero Ring Having Oxygen Or Sulfur (AREA)
Abstract
A process for preparing pyromellitic acid dianhydride (PMDA) as main monomer for synthesizing polyimide, a refractory insulating material, or as the solidifying agent of epoxy resin and polyester resin, or as assistant of powder paint features use of sym-tetratoluene or 5-isopropyl metatritoluene as raw material. Its advantages include low single consumption and high purity of product and output rate. The catalyst used in the process features higher selectivity, thermal stability and mechanical strength, resulting in high-load capacity of catalyst, high output rate, and long service life.
Description
The present invention relates to a kind of production method of pyromellitic acid anhydride, belong to the organic chemical industry field.
Pyromellitic acid anhydride, english abbreviation is PMDA, is the main synthon as high-temperature insulation material-polyimide, is widely used in fields such as space flight, aviation, electromechanics and electronics, simultaneously, also be important Resins, epoxy and the solidifying agent of alkyd resin and the auxiliary agent of powder coating.At present, refining pyromellitic acid anhydride adopts hot gas flow to carry method.It is raw material that this method only is confined to the durol, and the unit consumption height; Product purity is low, only is 96%, and device can only be produced pyromellitic acid anhydride, and support of the catalyst is single.
The invention provides a kind of new pyromellitic acid anhydride production method that unit consumption is low, product purity is high, yield is high.
Concrete production method of the present invention is:
With durol or 5-isopropyl pseudocumene is raw material, vaporize under 180 ℃～200 ℃ temperature through vaporizer, with air by 0.0023～0.35: 1 volume ratio is mixed, enter and carry out oxidizing reaction in the shell and tube reactor that is filled with catalyzer, catalyzer is following to air-activated 8-10 hour at 450 ℃ during this time, reactor links to each other with the fused salt groove, reacting by heating or carry out the reaction liberated heat, generate pyroreaction gas, enter first through interchanger, two, three traps carry out classification and capture, and sublimate into the solids crude product of pyromellitic acid anhydride, tail vapour enters water wash column, after organic acid is absorbed, discharges through water wash column top.
Thick all anhydride products that one, two, three traps are obtained are by thick acid anhydride: water: activated carbon=1: 4～6: 0.05～0.08 weight ratio proportioning is put into reactor, the hydrolysis decolouring, be heated to 85～95 ℃, stirred one hour, and carried out heat filtering, filtrate is put into cooling pool, crystallization, filter cake mixes in the coal to be burnt, and filtrate is chilled to the room temperature centrifuge dripping, obtains the Pyromellitic Acid of water content 15-30%.
Process for purification: moisture Pyromellitic Acid is put into bateau, bateau is put into dehydration still, reduced vacuum dehydration, emptying taking-up bateau again, puts into silica gel in the bateau, puts into the distillation still again, vacuum-sublimation, emptying are taken out the pyromellitic acid anhydride of purity＞98.5% still from distillation.
Catalyzer of the present invention is made of carrier and active substance.Wherein carrier can be α-Al
2O
3, also can adopt SiC ball type carrier or circular vectors.The ball type carrier size is φ 4-6mm, and the annular carrier size can be inner diameter, ID=4mm, external diameter OD=6mm, length L=6mm or inner diameter, ID=4mm, external diameter OD=7mm, length L=7mm.The catalyst activity material can be two kinds (A and B), and the A kind is by NH
4VO
3, TiCl
4, Na
3PO
4, (NH
4)
2MOO
3, H
2C
2O
4, H
2The O composition constitutes, and its part by weight is: 1: 0.04～0.05: 0.30～0.40: 0.04～0.1: 2～2.5: 5～5.5; The B kind is by NH
4VO
3, TiCl
4, (NH
4) H
2PO
4, KOH, CSNO
3, SiN, H
2C
2O
4, H
2The O composition constitutes, and its mol ratio is :=1: 0.20～0.35: 0.05～0.2: 0.05～0.1: 0.04: 0.08: 2.0～3.0: 35～40.
Catalyst Production technology: the active substance that will form in proportion is mixed with spray coating liquor, its method is that distilled water and oxalic acid are put into still, stirring is warming up to 80-90 ℃, after oxalic acid all dissolves, solution is chilled to 50-70 ℃, slowly add ammonium meta-vanadate, under temperature 75-85 ℃, continue to be stirred to ammonium meta-vanadate and all dissolve.Add tertiary sodium phosphate, ammonium molybdate or Secondary ammonium phosphate, potassium hydroxide, cesium nitrate, silicon nitride.Be chilled to 30-40 ℃, slowly add titanium tetrachloride under stirring, promptly be mixed with spray solution.Carrier is put into rotary drum, be warming up to 230-300 ℃, under rotating, evenly spray on the carrier, active substance weightening finish 5-10% with spray gun.Put into High Temperature Furnaces Heating Apparatus, be warming up to 450 ℃ with 100 ℃/hour speed, constant temperature 4 hours continues to be warming up to 500-580 ℃, and constant temperature 8-10 hour, naturally cool to 100 ℃, can come out of the stove, catalyzer is stand-by.
The production method unit consumption of pyromellitic acid anhydride provided by the present invention is low, product purity is high, yield is high, catalyst system therefor in this production method has higher selectivity, and thermostability and physical strength can improve catalyst loading significantly, improve equal acid anhydride yield, prolonged work-ing life.
Specific embodiment:
1, with the durol be raw material:
Adopting B kind Catalyst Production device is 150 liters, air speed: 4000 liters/liters per hour, catalyst loading 70 grams per liters hour, 430-450 ℃ of hot(test)-spot temperature of reaction, temperature of molten salt 380-385 ℃, 1750 kilograms of durol charging capacitys (durol content＞95%), smart anhydride product: 948.2 kilograms, promptly unit consumption is 1.85 tons of durol/tons.
2, with the durol be raw material:
Adopting A kind Catalyst Production device is 466 liters, air speed: 3800-4200 liter/liters per hour, catalyst loading 65 grams per liters hour, 4 30-450 ℃ of reaction hot(test)-spot temperatures, temperature of molten salt 375-380 ℃, durol throwing amount material: 1357.25 kilograms (durol content＞95%), smart acid anhydride: 712.6 kilograms, promptly unit consumption is 1.91 tons of durol/tons.
3, adopting the 5-isopropyl pseudocumene is raw material:
Adopting A kind Catalyst Production device is 100 liters, air speed: 7000-8000 liter/liters per hour, catalyst loading 70 grams per liters hour, hot(test)-spot temperature: 435-440 ℃, 165 kilograms of 5-isopropyl pseudocumene (content＞65%), 60.5 kilograms of smart all anhydride products, promptly smart acid anhydride rate: 36.7%.
Claims (3)
1, the invention provides a kind of pyromellitic acid anhydride production method, it is characterized in that with durol or 5-isopropyl pseudocumene be raw material, after the vaporization, mix by the 0.0023-0.35 volume ratio with air, enter the shell and tube reactor that is filled with catalyzer, under 430 ℃-450 ℃, Catalytic Oxygen changes into pyroreaction gas, through interchanger, the classification trap obtains the thick product of pyromellitic acid anhydride, with the thick product of pyromellitic acid anhydride by thick acid anhydride: water: the gac weight ratio is 1: 4～6: 0.05～0.08 to be heated to 85～95 ℃, dissolving, decolouring, filter, be cooled to room temperature, centrifuge dripping promptly gets Pyromellitic Acid, and again through vacuum hydro-extraction, vacuum-sublimation obtains the smart pyromellitic acid anhydride of purity＞98.5%.
2, pyromellitic acid anhydride production method as claimed in claim 1 is characterized in that catalyzer is made up of carrier and active substance, and carrier can be α-Al
2O
3Or SiC ball-type carrier (φ 5-6mm) or circular vectors, its active substance can be by NH
4VO
3, TiCl
4, Na
3PO
4, (NH
4)
2MOO
3, H
2C
2O
4And H
2The O composition constitutes, and its part by weight is 1: 0.04～0.05: 0.30～0.40: 0.04～0.1: 2～2.5: 5～5.5; Also can be by NH
4VO
3, TiCl
4, (NH
4) H
2PO
4, KOH, CSNO
3, SiN, H
2C
2O
4And H
2O constitutes, and its mole ratio is 1: 0.20～0.35: 0.05～0.2: 0.05～0.1: 0.04: 0.08: 2.0～3.0: 35～40.
3, pyromellitic acid anhydride production method as claimed in claim 1, it is characterized in that method for preparing catalyst is as follows: the proportioning by catalyst activity substance A, B kind is made spray coating liquor, under 230 ℃-260 ℃, spray on the carrier active substance weightening finish 5-10%.The catalyzer that spray is good is placed in the High Temperature Furnaces Heating Apparatus and is heated to 450 ℃ with 100 ℃/hour, and constant temperature 4 hours continues to be warming up to 500～580 ℃, constant temperature 8-10 hour, naturally cool to 100 ℃ of taking-ups, catalyzer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 98116910 CN1245171A (en) | 1998-08-17 | 1998-08-17 | Process for preparing sym-phenyltetraformic dianhydride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 98116910 CN1245171A (en) | 1998-08-17 | 1998-08-17 | Process for preparing sym-phenyltetraformic dianhydride |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1245171A true CN1245171A (en) | 2000-02-23 |
Family
ID=5225259
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 98116910 Pending CN1245171A (en) | 1998-08-17 | 1998-08-17 | Process for preparing sym-phenyltetraformic dianhydride |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1245171A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106423237A (en) * | 2016-02-03 | 2017-02-22 | 如皋市乐恒化工有限公司 | Benzene tetramethyl acid dianhydride catalyst and preparation method thereof |
| CN107722273A (en) * | 2017-10-27 | 2018-02-23 | 济南隆凯能源科技有限公司 | A kind of low cost polyimide Moulding powder produces chain |
| CN108586227A (en) * | 2018-04-24 | 2018-09-28 | 鹏辰新材料科技股份有限公司 | A kind of preparation method of the Pyromellitic Acid based on porous black phosphorus alkene catalyst |
| CN109666032A (en) * | 2018-12-11 | 2019-04-23 | 沾化大荣化工科技有限公司 | A kind of preparation method of pyromellitic dianhydride |
-
1998
- 1998-08-17 CN CN 98116910 patent/CN1245171A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106423237A (en) * | 2016-02-03 | 2017-02-22 | 如皋市乐恒化工有限公司 | Benzene tetramethyl acid dianhydride catalyst and preparation method thereof |
| CN106423237B (en) * | 2016-02-03 | 2019-03-15 | 如皋市乐恒化工有限公司 | A kind of catalyst and preparation method thereof for producing pyromellitic acid anhydride |
| CN107722273A (en) * | 2017-10-27 | 2018-02-23 | 济南隆凯能源科技有限公司 | A kind of low cost polyimide Moulding powder produces chain |
| CN107722273B (en) * | 2017-10-27 | 2020-06-09 | 潍坊弘润新材料有限公司 | Low-cost production method of polyimide molding powder |
| CN108586227A (en) * | 2018-04-24 | 2018-09-28 | 鹏辰新材料科技股份有限公司 | A kind of preparation method of the Pyromellitic Acid based on porous black phosphorus alkene catalyst |
| CN108586227B (en) * | 2018-04-24 | 2020-10-20 | 鹏辰新材料科技股份有限公司 | Preparation method of pyromellitic acid based on porous black phosphorus catalyst |
| CN109666032A (en) * | 2018-12-11 | 2019-04-23 | 沾化大荣化工科技有限公司 | A kind of preparation method of pyromellitic dianhydride |
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