CN1318376C - Method for mfg.terephthalic acid - Google Patents
Method for mfg.terephthalic acid Download PDFInfo
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- CN1318376C CN1318376C CNB2004100982251A CN200410098225A CN1318376C CN 1318376 C CN1318376 C CN 1318376C CN B2004100982251 A CNB2004100982251 A CN B2004100982251A CN 200410098225 A CN200410098225 A CN 200410098225A CN 1318376 C CN1318376 C CN 1318376C
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
- C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/42—Separation; Purification; Stabilisation; Use of additives
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C63/00—Compounds having carboxyl groups bound to a carbon atoms of six-membered aromatic rings
- C07C63/14—Monocyclic dicarboxylic acids
- C07C63/15—Monocyclic dicarboxylic acids all carboxyl groups bound to carbon atoms of the six-membered aromatic ring
- C07C63/26—1,4 - Benzenedicarboxylic acid
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- Oil, Petroleum & Natural Gas (AREA)
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Abstract
To provide a method for producing terephthalic acid, capable of reusing discharged water from a process of purifying crude terephthalic acid as the water for purifying the crude terephthalic acid and further capable of improving the yield of terephthalic acid. This method for producing the terephthalic acid is provided by dissolving the crude terephthalic acid obtained by oxidizing p-xylene by heating under pressure, evaporating water by reducing the pressure to crystallize the terephthalic acid, bringing condensed water obtained by condensing the evaporated water in contact with p-xylene, then separating the water and reusing in any of the processes of the production of the terephthalic acid. Also, the condensed water is reused as a water for dissolving the crude terephthalic acid. It is preferable to evaporate 30-70 wt.% water necessary for dissolving the crude terephthalic acid from a crystallization vessel by adjusting the crystallization condition and to remove impurity from the evaporated water by a p-xylene extraction.
Description
Technical field
The present invention relates to a kind of when making terephthalic acid employed water solvent utilize method again.
Background technology
The preparation method of highly purified terephthalic acid is for to put into water with crude terephthalic acid, carry out rising temperature for dissolving adding to depress, in the presence of hydrogen, make it with catalyzer, for example contact with palladium, to be reduced to the paratolunitrile of being removed by partial crystallization easily as the oxidation intermediates 4-carboxyl benzaldehyde of major impurity in the crude terephthalic acid, after removing impurity with partial crystallization again, make by solid-liquid separation.The water that use as solvent this moment is because of containing a lot of impurity, and it is discarded to be used as waste water, thereby the large-scale wastewater treatment equipment of needs.
From this water, remove the method for impurity, open in No. 2899927, patent for example.This method is to carry out water after the solid-liquid separation for the above-mentioned terephthalic acid that carries out behind the partial crystallization, uses p-Xylol to carry out extractive method.But, in this method, as for the refining and water that utilize again of crude terephthalic acid, fail impurity is removed purity to necessity.
In addition, as the device of partial crystallization terephthalic acid, can use the device that makes the hurried cooling of water by decompression.The vaporize water that produces in this operation, because of not containing contained high-boiling-point impurity in the waste water after the solid-liquid separation, therefore think that condensed water can be got back to and handle in the partial crystallization groove and directly take out, directly use once more as the water that is used for refining crude terephthalic acid.But therefore, owing to contain a large amount of paratolunitriles in the vaporize water, adopt the concentration of paratolunitrile in the finished product of this method to uprise.Therefore, must be by reducing the concentration of the 4-carboxyl benzaldehyde in the crude terephthalic acid in advance, keeping concentration as paratolunitrile among the high purity terephthalic acid of the finished product, thus the problem that causes the manufacturing cost of crude terephthalic acid to increase.
Summary of the invention
In the method with extracting impurity the waste water of p-Xylol after solid-liquid separation, after the p-Xylol extracting, still have a lot of impurity in the waste water at present, can not use once more as the water of refining crude terephthalic acid.In addition, in the later on direct round-robin method of the vaporize water condensation that produces in the operation with the partial crystallization crude terephthalic acid, for keeping high purity terephthalic acid's purity, must reduce the concentration of the 4-carboxyl benzaldehyde in the crude terephthalic acid, the problem that therefore exists the manufacturing cost of crude terephthalic acid to increase.
Further the problem that exists is, this not only causes the paratolunitrile and the waste water that can become the finished product terephthalic acid through oxidation together to be dropped, but also must have large-scale wastewater treatment equipment.
The invention provides a kind of method, can be utilized as for example water of refining crude terephthalic acid once more, further improve the yield of terephthalic acid making with extra care the waste water of discharging in the operation of crude terephthalic acid.
The present invention relates to a kind of manufacture method of terephthalic acid, be the crude terephthalic acid that to obtain after the oxidation of p-xylene after adding that depressing heats up and making it be dissolved in water, make terephthalic acid generation partial crystallization by reduction vaporization moisture, the water of condensation that the vaporize water condensation that produces this moment is obtained is with after p-Xylol contacts, and the water of condensation that separation obtains is recycling in any manufacturing process of terephthalic acid.
The present invention also provide a kind of with water of condensation as the method utilized once more of water of dissolving crude terephthalic acid and by with crude terephthalic acid under 5MPa-G or the pressure more than the 5MPa-G, be warming up to after temperature more than 225 ℃ or 225 ℃ dissolves, through the decompression of one-level formula or multi-stage type, evaporate 30～70 weight % be used for dissolving crude terephthalic acid water method and make condensing temperature reach method more than 70 ℃ or 70 ℃ in the condensation operation of condensation evaporation water.
Water of condensation behind the water condensation that evaporates is contacted with p-Xylol down at 40～200 ℃.
The present invention also provides a kind of and separates the method that the water of condensation obtain carries out bubbling after making the contact p-Xylol with gas shape material.Gas shape material preferably uses nitrogen or water vapour.
In addition, the present invention also provide a kind of will with water of condensation contact after separate the p-Xylol that obtains and be supplied to oxidation operation, the method of using as the raw material of making crude terephthalic acid or the p-Xylol that contains in the gas shape material behind the bubbling is supplied to oxidation operation is as the method for the raw material of making crude terephthalic acid.
By using p-Xylol as the raw material of terephthalic acid as extractant, needn't carry out usually must main equipment and the extractant of energy utilize operation again, can make abandon at present as waste water, must be with large-scale wastewater treatment equipment waste water that handle, that from the refining step of crude terephthalic acid, produce, the water as refining crude terephthalic acid utilizes again once more.
And, the paratolunitrile in the waste water that abandons can be converted into the target product terephthalic acid and reclaim.
Description of drawings
Fig. 1 illustrates the explanatory view that waste water of the present invention is carried out one of purified implementation method example.(embodiment 1)
[drawing reference numeral explanation]
1, crude terephthalic acid supply passageway
2, purified terephthalic
3, condenser
4, waste water
5, partial crystallization operation vaporize water
6, p-Xylol
7, oxidation operation
8, heating for dissolving operation
9, hydrogenation process
10, partial crystallization operation
11, solid-liquid separation process
12, drying process
13, extracting operation
13-1, the 1st grade of stirring
13-2, the 1st grade of standing separation
13-3, the 2nd grade of stirring
13-4, the 2nd grade of standing separation
14, water
15, distilled water
16, stripping tower
17, lower-boiling impurity
18, p-Xylol
Embodiment
P-Xylol is placed in the acetate solvate, uses cobalt compound and manganic compound, bromine compounds, under 160～260 ℃ of reaction pressure 0.4～5MPa-G, temperature of reaction, in air, carry out oxidation and make crude terephthalic acid as catalyzer.Major impurity in this crude terephthalic acid is as 4-carboxyl benzaldehyde 500～5000 ppm by weight of oxidation intermediates and paratolunitrile 100～1000ppm weight.The lower-boiling impurity that other impurity has high-boiling-point impurity that phenylformic acid, hydroxymethyl-benzoic acid, m-phthalic acid etc. and they obtain with bound in various forms or decomposition to obtain.
With the crude terephthalic acid that obtains thus, at 5MPa-G or more than the 5MPa-G, be preferably under the pressure of 7～9MPa-G, be warming up to more than 225 ℃ or 225 ℃, preferably be warming up to 250 ℃～310 ℃, it is dissolved in the water.P-phthalic acid at concentration in this moment water is adjusted to 10～40 weight %, is preferably in the scope of 20～35 weight %.If the concentration of terephthalic acid is lower, then the water yield of Shi Yonging increases, and causes followingly being used for the device that water utilizes again and becoming big, and is therefore not preferred.And the concentration of terephthalic acid is when higher, and as described below, when Jiang Shui evaporated 30～70 weight %, impurity concentration increased in the mother liquor that does not evaporate, and the impurity concentration among the finished product high purity terephthalic acid increases, and is therefore not preferred.
Then, in the presence of hydrogen with catalyzer for example palladium contact, will be reduced to as the oxidation intermediates 4-carboxyl benzaldehyde of major impurity in the crude terephthalic acid and be easy to the paratolunitrile that partial crystallization is removed, then, with one-level formula or multi-stage type, preferably reduce pressure, evaporate moisture with 3～7 grades of formulas.
Among the present invention, though utilize and the bigger steam output of preferred employing for the water after the evaporation is made with extra care again, but the concentration of impurity uprises in the mother liquor that does not evaporate when steam output is excessive, and the concentration as impurity among the high purity terephthalic acid of finished product is increased, and is therefore not preferred.Therefore, it is 30～70 weight % of water that the adjustment decompression operation makes steam output, is preferably 35～60 weight %.Vaporization heat by evaporation makes temperature be reduced to 100～175 ℃, separates out terephthaldehyde's acid crystal.5～50 weight % of paratolunitrile are transferred in the water that evaporates, and all the other nearly all impurity remain in the mother liquor.In addition, though the lower-boiling impurity that trace exists also be transferred in the water that evaporates, can be by the water that will evaporate more than 70 ℃ or 70 ℃, preferably under 80～100 ℃ temperature condensation to remove these materials.For removing lower-boiling impurity, though preferred higher condensing temperature, in order under atmospheric pressure to carry out the operation of following extracting and bubbling with cheap device, preferred upper temperature limit is 100 ℃.
The major impurity of having removed thus in the water of condensation of high-boiling-point impurity and lower-boiling impurity is a paratolunitrile, and its concentration is 100～5000 ppm by weight.With respect to this water of condensation of 100 weight parts, make itself and 3～200 weight parts, be preferably 5～100 weight parts, more preferably the p-Xylol of 10～35 weight parts contacts, to remove the paratolunitrile in the water of condensation.The amount of p-Xylol is many more, paratolunitrile to remove efficient high more, therefore preferred.But, because the raw material as crude terephthalic acid after the p-Xylol extracting is used, so the upper limit of p-Xylol amount must depend on whole balance.
The temperature that water of condensation is contacted with p-Xylol is generally 40～200 ℃, is preferably 60～150 ℃, more preferably 80～100 ℃.
Because can improve the rate of removing of paratolunitrile, so preferably adopt 2～10 grades, 2～4 grades counter-flow multi-level extracting more preferably by the counter-flow multi-level extracting.Needn't remove paratolunitrile fully among the present invention, for example remove more than 70% or 70% and get final product.Extracting progression is enough below 10 grades or 10 grades.In addition, increase extracting progression for the amount that reduces extraction solvent usually, but, therefore do not need the needed extractant re-use device of common extraction procedure because the raw material that can be used as crude terephthalic acid as the p-Xylol of extractant among the present invention uses.With respect to 100 weight part water of condensation, can use the above p-Xylol of 10 or 10 weight parts as extractant, extracting progression just can reach the rate of removing fully below 4 grades or 4 grades.For example, countercurrent extraction progression is 2 grades, uses 25 weight part p-Xylol with respect to 100 weight part water of condensation, can remove the paratolunitrile in the above water of condensation of 90 weight % or 90 weight %.
Condensation water quantity can reach 50t/hr or more than the 50t/hr, not adopt large-scale single tower structure for avoiding the bias current problem in the extraction tower, but handle side by side better with the multitower structure in the production plant of large-scale terephthalic acid.Therefore, the amount of water of condensation reaches 50t/hr or 50t/hr when above in large-scale Production of Terephthalic Acid factory, and the mixing machine distractor-type device that can preferably be connected in series and be constituted by stirrer and standing separation device carries out the multi-stage type extracting.The wing tip speed of agitator blades is 0.25m/ second or 0.25m/ more than second, is preferably 0.5～5m/ second.High-speed stirring can improve extraction efficiency and implement device miniaturization, and is therefore preferred, but stirring velocity is when too fast, prolong because p-Xylol generation micronize causes being separated into 2 layers time of repose, so speed is preferably 5m/ second or 5m/ below second.The wing tip speed of blade of stirrer is that the time of repose of 0.5～5m/ during second is 1～30 minute in the intermediate stage of adverse current multistage extraction, is preferably 2～5 minutes, and level is 2～60 minutes at the two ends of adverse current multistage extraction, is preferably 5～15 minutes.
Be to reclaim residual p-Xylol in the water that the final level of adverse current multistage extraction discharges, carry out bubbling with the water of gas shape material after to extracting.At this moment,,, from nitrogen, reclaim relatively difficulty of p-Xylol, preferably use water vapor to reclaim p-Xylol by condensation though can use nitrogen as gas shape material.This moment water vapor amount, relative 100 weight part water of condensation are 0.05～10 weight part, are preferably 0.5～5.0 weight part, more preferably 1.0～2.0 weight parts.The rate of removing of the many more p-Xylol of the amount of water vapor is high more, even but a small amount of remaining quality that also can not have influence on as the high purity terephthalic acid of finished product is arranged, the p-Xylol more than 95% or 95% of sneaking into evaporates in the partial crystallization groove, return extraction plant then, so the water of condensation of relative 100 weight parts, the amount of water vapor is to get final product more than 0.5 weight part or 0.5 weight part.In addition, with respect to 100 weight part water of condensation, the amount of water vapor is 1.0 weight parts or 1.0 weight parts when above, need not to be provided for removing the special ventage of p-Xylol stink, and is therefore preferred.
In addition, also can use coalescing agent in order to remove p-Xylol.As coalescing agent, have for example Japanese Pall Co., Ltd. as coalescing agent fluorine-type resin, commodity Phasesep by name.At this moment, owing to may there be the situation that contains the terephthalic acid of following the spittle, therefore the velocity of evaporation that is necessary the water surface of evaporation by making partial crystallization is per unit square metre 30.00kg/hr or below the 30.00kg/hr, be preferably 2.000kg/hr or below the 2.000kg/hr, follow the amount of the terephthalic acid of the spittle with reduction, simultaneously, make the temperature that adds before the coalescing agent more than 70 ℃ or 70 ℃, be preferably 90～100 ℃, so that terephthalic acid is not separated out.
The p-Xylol that goes out behind the impurity because of extracting does not contain high-boiling-point impurity, does not influence quality, does not use as raw material so can not change condition when producing crude terephthalic acid.
Below put down in writing embodiments of the invention, but the present invention is not limited to following embodiment.
[embodiment 1]
Fig. 1 illustrates one of embodiments of the invention example.Crude terephthalic acid 1 with water 14 and distilled water 15, in heating for dissolving operation 8, is warming up to 300 ℃ and dissolves under 10MPa-G.The relative 1.0 weight part crude terephthalic acids of the total amount of water are 3.0 weight parts.After the dissolving, in hydrogenation process 9, the 4-carboxyl benzaldehyde in the crude terephthalic acid is reduced to paratolunitrile, separates out terephthalic acid in partial crystallization operation 10.At this moment, making the pressure of final partial crystallization groove is 0.5MPa-G, makes the 50 weight % evaporation of water.The terephthalic acid of separating out is separated in solid-liquid separation process 11, and dried finished products is taken out as high purity terephthalic acid 2 in drying process 12.
Partial crystallization operation vaporize water 5 is transported to condenser 3 95 ℃ of following condensations.The concentration of the paratolunitrile in the water of condensation is 700 ppm by weight at this moment.Be transported to extracting operation 13 then, carry out 2 stage countercurrent extraction procedure.That is,, make it in the 1st grade of stirrer 13-1, contact 2 minutes with 25 weight part p-Xylol corresponding to 100 weight part water of condensation.In the 1st grade of standing separation machine 13-2, leave standstill then and separated in 3 minutes, make 100 weight part water of condensation in the 2nd grade of stirrer 13-3, contact 2 minutes once more, separate after in the 2nd grade of standing separation machine 13-4, leaving standstill 5 minutes with the p-Xylol of 25 weight parts.This moment, p-Xylol flowed with respect to the mode of water with adverse current.Stirrer has the blade of 4 inclinations, and blade is that 3.0m/ is rotated second with wing tip speed.
Paratolunitrile concentration in the water that obtains thus is 30 ppm by weight, and the concentration of p-Xylol is 500 ppm by weight.It is transported to stripping tower 16, carries out bubbling with the water vapor amount of 1.0 weight parts with respect to 100 weight parts waters.The concentration of paratolunitrile is 30 ppm by weight or below 30 ppm by weight in the water behind this bubbling, and the concentration of p-Xylol is 1 ppm by weight or below 1 ppm by weight.
P-Xylol after the extracting is transported in the oxidation operation 7 with p-Xylol with the oxidation raw material from p-Xylol supply passageway 18, uses as the raw material of making crude terephthalic acid.
By this operation, can not reduce the concentration of impurity in the crude terephthalic acid in advance, can be with 50% utilizing again of being used for the water of crude terephthalic acid after refining.
Industrial applicability
Do not consume mass energy ground refined wastewater, make it be in the state that can recycle, make order Before the paratolunitrile that always goes out of use can be converted into the final products terephthalic acid (TPA) and carry out Reclaim.
Claims (8)
1. the manufacture method of a terephthalic acid, it is characterized by, depressing heats up is dissolved in the water it to the crude terephthalic acid that oxidation of p-xylene is obtained adding, make that P-phthalic acid at concentration is 10 weight %～40 weight % in the water, in the presence of hydrogen, the 4-carboxyl benzaldehyde is reduced to paratolunitrile then, next in operation by decompression partial crystallization terephthalic acid, the water of condensation that obtains behind the water of condensation evaporation is contacted with p-Xylol, and the water of condensation after will separating then is used in arbitrary operation of making terephthalic acid again.
2. the manufacture method of terephthalic acid as claimed in claim 1 is characterized by, and the water of the water of condensation after separating as the above-mentioned crude terephthalic acid of dissolving is utilized again.
3. the manufacture method of terephthalic acid as claimed in claim 1 or 2, it is characterized by, crude terephthalic acid is warming up to more than 225 ℃ or 225 ℃ under 5MPa-G or the pressure more than the 5MPa-G, after it is dissolved in the water, by 1 grade or multi-step pressure reduction, be used in water evaporation 30～70 weight % of dissolving crude terephthalic acid.
4. the manufacture method of terephthalic acid as claimed in claim 1 or 2 is characterized by, and in the operation of condensation evaporation water, condensing temperature is reached more than 70 ℃ or 70 ℃.
5. the manufacture method of terephthalic acid as claimed in claim 1 or 2 is characterized by, and makes resulting water of condensation behind the water condensation of evaporation, contacts with p-Xylol down at 40～200 ℃.
6. the manufacture method of terephthalic acid as claimed in claim 1 or 2 is characterized by, will with p-Xylol contact after separate the water of condensation that obtains and carry out bubbling with gas shape material.
7. the manufacture method of terephthalic acid as claimed in claim 6 is characterized by, and the gas shape material that is used for bubbling is nitrogen or water vapour.
8. the manufacture method of terephthalic acid as claimed in claim 1 or 2 is characterized by, will with water of condensation contact after separate the p-Xylol that obtains and be used for oxidation operation, as the raw material of making crude terephthalic acid.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP421776/2003 | 2003-12-19 | ||
| JP2003421776 | 2003-12-19 |
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| Publication Number | Publication Date |
|---|---|
| CN1651393A CN1651393A (en) | 2005-08-10 |
| CN1318376C true CN1318376C (en) | 2007-05-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB2004100982251A Active CN1318376C (en) | 2003-12-19 | 2004-11-30 | Method for mfg.terephthalic acid |
Country Status (3)
| Country | Link |
|---|---|
| KR (1) | KR100650536B1 (en) |
| CN (1) | CN1318376C (en) |
| TW (1) | TWI266764B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009141968A1 (en) * | 2008-05-20 | 2009-11-26 | 株式会社日立プラントテクノロジー | Method for treating separated mother liquor from terephthalic acid refinement |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04279550A (en) * | 1991-03-07 | 1992-10-05 | Mitsui Petrochem Ind Ltd | Treatment of mother solution of purified terephthalic acid |
| CN1264360A (en) * | 1997-07-16 | 2000-08-23 | 纳幕尔杜邦公司 | Improved process for recovering hydrogen in producing pure terephthalic acid |
| CN1374937A (en) * | 1999-09-21 | 2002-10-16 | 纳幕尔杜邦公司 | Process for producing pure terephthalic acid with improved recovery of precursors, solvent and mentyl acetate |
| WO2002098836A1 (en) * | 2001-06-04 | 2002-12-12 | Eastman Chemical Company | Process for the production of purified terephthalic acid |
-
2004
- 2004-10-25 KR KR1020040085175A patent/KR100650536B1/en active IP Right Grant
- 2004-11-09 TW TW093134052A patent/TWI266764B/en active
- 2004-11-30 CN CNB2004100982251A patent/CN1318376C/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH04279550A (en) * | 1991-03-07 | 1992-10-05 | Mitsui Petrochem Ind Ltd | Treatment of mother solution of purified terephthalic acid |
| CN1264360A (en) * | 1997-07-16 | 2000-08-23 | 纳幕尔杜邦公司 | Improved process for recovering hydrogen in producing pure terephthalic acid |
| CN1374937A (en) * | 1999-09-21 | 2002-10-16 | 纳幕尔杜邦公司 | Process for producing pure terephthalic acid with improved recovery of precursors, solvent and mentyl acetate |
| WO2002098836A1 (en) * | 2001-06-04 | 2002-12-12 | Eastman Chemical Company | Process for the production of purified terephthalic acid |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1651393A (en) | 2005-08-10 |
| TWI266764B (en) | 2006-11-21 |
| KR20050062360A (en) | 2005-06-23 |
| TW200530175A (en) | 2005-09-16 |
| KR100650536B1 (en) | 2006-11-27 |
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