CN1277184A - Production process of aromatic binary carboxylic acid - Google Patents
Production process of aromatic binary carboxylic acid Download PDFInfo
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- CN1277184A CN1277184A CN 00115599 CN00115599A CN1277184A CN 1277184 A CN1277184 A CN 1277184A CN 00115599 CN00115599 CN 00115599 CN 00115599 A CN00115599 A CN 00115599A CN 1277184 A CN1277184 A CN 1277184A
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Abstract
The production process features that the same extractant as the reactant is used to separate solvent from water. Therefore, the production process has low production cost, high product quality, less investment and power consumption compared with available technology, and thus vast application range.
Description
The present invention relates to the production method of aromatic binary carboxylic acid, relate in particular to the separation method of solvent and water in terephthalic acid or the production process of terephthalic acid/m-phthalic acid.
Terephthalic acid and m-phthalic acid are a kind of important Organic Chemicals, and annual global output is about 4,000 ten thousand tons, is mainly used in the production of polyester.Its production method generally comprises the oxidizing reaction of raw material in solvent, separation and the solvent and the steps such as separating of water of product, and acetic acid is the solvent of using always.The effect of solvent is catalyst-solvent, increases and conduct heat and mass transfer, and helps the dispersion of aromatic acid xln.Generally speaking, the part by weight of solvent and reaction raw materials is 3～5.Acetate solvate recycles after separating.On the other hand, when generating aromatic carboxylic acid, go back by-product water.With the Production of Terephthalic Acid is example, 1 ton of about 0.22 ton of water of terephthalic acid by-product.Therefore, the partitioning cycle of solvent need experience two steps, and the one, with separating of solid terephthalic acid, generally adopt multiple crystallization to add the method for centrifugation, the 2nd, solvent separates with water.The separation efficiency of solvent and water will directly influence the quality of production cost and product, therefore many Patent publish this isolation technique.
U.S. Pat P4250330 and German Patent GB1576787 disclose respectively and have adopted isobutyl acetate and the n-butyl acetate azeotropic distillation as the heterogeneous azeotropic agent.Chinese patent 96112335.4 discloses a kind of method of improving above two kinds of methods.The disclosed technology of above-mentioned patent all adopt with production process in raw material and irrelevant the 3rd medium of product as extraction agent, not only cost an arm and a leg, and influence the quality of product;
Chinese patent 95104364.1 discloses a kind of extraction separation method that adopts the tri-alkoxy phosphine as extraction agent, and this method mainly is suitable for reclaiming acetic acid from the aqueous solution of low acetate concentration, and extraction agent costs an arm and a leg, and loss is bigger.
The objective of the invention is to disclose a kind of is the production method of aromatic binary carboxylic acid of the mixture of the separating acetic acid of extraction agent and water with the reaction raw materials.
Design of the present invention is such:
At aromatic acid, especially in the production of terephthalic acid or m-phthalic acid, raw material is respectively p-Xylol or m-xylene, and they and water do not dissolve each other.But Dichlorodiphenyl Acetate, dimethylbenzene or m-xylene but can be used as solvent.Therefore, the present invention adopts corresponding raw material p-Xylol or m-xylene as the extraction agent of acetic acid one water sepn, not only can reduce cost, and can improve the quality of products.
According to above-mentioned design, the contriver proposes to realize that the technical scheme of the object of the invention is as follows:
The preparation method of terephthalic acid or m-phthalic acid comprises following three steps:
1. dimethylbenzene or m-xylene in acetic acid with the oxidation reaction process of air, in this reaction process, dimethylbenzene or m-xylene are in acetum, in the presence of catalyzer, reaction generates terephthalic acid or m-phthalic acid;
2. the sepn process of terephthalic acid or m-phthalic acid, in this sepn process, terephthalic acid that 1. step generates or m-phthalic acid separate with aqueous acetic acid;
3. the sepn process of acetic acid and water, in this process, acetic acid separates with water.
In the above-mentioned steps, 1. p-Xylol or m-xylene are prior art with the reaction process of air and sepn process 2. in acetum, and the present invention repeats no more, and step 3. the sepn process of acetic acid and water may further comprise the steps:
Extraction agent p-Xylol or m-xylene enter extraction tower from the bottom of extraction tower, aqueous acetic acid by step sepn process 2. enters extraction tower from the top of extraction tower, because the proportion of p-Xylol or m-xylene is about 0.8, upwards flow, the proportion of aqueous acetic acid is about 1.0, then flows downward.After acetic acid and p-Xylol or m-xylene mixed, its proportion was called oil phase between 0.85～0.90, flowed out by the extraction tower top; Isolated water is gone out by tower bottom flow.Because water is all very low in the solubleness and the solubleness in the m-xylene of p-Xylol, the water-content in the cat head oil phase is very low, and weight percent is less than 0.1%, and the xylene content of aqueous phase is also very low at the bottom of the tower, and weight percent is less than 0.1%.Therefore, in extraction tower, separating of water and acetic acid is quite thorough, and number of theoretical plate is 10～25.
The service temperature of extraction tower is 50～120 ℃, and preferred temperature is 70～80 ℃.
The weight ratio of p-Xylol or m-xylene and aqueous acetic acid is: 1: (1～10), preferred ratio is 1: (2～4).
Enter the rectifying separation that rectifying tower carries out acetic acid and dimethylbenzene or m-xylene by the effusive acetic acid in extraction tower top and p-Xylol or m-xylene mixing solutions.The boiling point of p-Xylol is 144 ℃, and the boiling point of m-xylene is 138 ℃, and the boiling point of acetic acid is 118 ℃, and acetic acid and p-Xylol form azeotrope, and the normal pressure azeotropic point is 115 ℃, consists of acetic acid 70% (wt).Therefore, effusive from rectifying tower top is the mixture of acetic acid and p-Xylol or m-xylene, and directly Returning oxidation reactor recycles once more;
What come out at the bottom of the rectifying tower is p-Xylol or m-xylene, through cooling between 50～120 ℃, enters the extraction tower bottom behind additional dimethylbenzene or the m-xylene again.Generally speaking, the ratio of the weight of p-Xylol or m-xylene internal circulating load and add-on is between 3～10.The tower top temperature of rectifying tower is 113～116 ℃.
According to reaction quantitative relation formula, as can be known, 1 ton of p-Xylol acid consumes 0.6385 ton of p-Xylol, produces 0.22 ton of water.If entering the aqueous acetic acid water content of extraction tower is 30% (wt), then 0.22 ton of water is taken 0.513 ton of acetic acid out of.Like this, if the required p-Xylol of oxidation reactor all passes through extraction tower and rectifying tower, then the acetic acid content of rectifying tower top is that 44.55% (wt) promptly met the demands.Therefore, the separation task of rectifying tower is less.Under suitable reflux ratio situation, number of theoretical plate is 10～25.
Below will carry out detailed narration to technical scheme of the present invention by accompanying drawing.
Fig. 1 is the 3. schema of the sepn process of acetic acid and water of step of the present invention.
As seen from Figure 1, extractant dimethylbenzene or meta-xylene enter from the bottom of extraction tower 1 Extraction tower 1, the aqueous acetic acid by step separation process 2. is from the top of extraction tower 1 Enter extraction tower 1, dimethylbenzene or meta-xylene upwards flow, and aqueous acetic acid is then to dirty Moving. The mixed oil phase of acetic acid and dimethylbenzene or meta-xylene is flowed out by extraction tower 1 top; Isolated water is gone out by tower bottom flow.
The operating temperature of extraction tower is 50～120 ℃.
The weight ratio of paraxylene or meta-xylene and aqueous acetic acid is: 1: (1～10), preferred ratio is 1: (2～4).
The acetic acid that is flowed out by extraction tower 1 top and paraxylene or meta-xylene mixed solution advance Enter rectifying column 2 and carry out separating of acetic acid and dimethylbenzene or meta-xylene. From rectifying column 2 top streams The mixture for acetic acid and paraxylene or meta-xylene that goes out can directly return oxidation reaction Device recycles again;
What came out in 2 ends of rectifying column is paraxylene or meta-xylene, through circulating pump 3, cooling Device 4 cools between 50～120 ℃, enters extraction tower behind additional dimethylbenzene or the meta-xylene again 1 bottom. Generally speaking, the weight of paraxylene or meta-xylene internal circulating load and addition it Than between 3～10.
Cooling procedure has two kinds of methods, and the one, directly by water cooling, the 2nd, and enter rectifying column 2 Acetic acid and paraxylene or meta-xylene solution carry out heat exchange, like this, 2 ends of rectifying column The heat of fluid of higher temperature can further be utilized, be conducive to energy-conservation. Simultaneously, The paraxylene on rectifying column 2 tops or meta-xylene and vinegar stock also can be with the sides of vapour phase Formula deoxidation reactor also more is conducive to energy-conservation.
Structure and the form of extraction tower 1 of the present invention and rectifying column 2 are unrestricted. That extraction tower 1 can adopt is board-like, filler, rotating plate type or oscillatory type, and rectifying column 2 also can adopt Board-like and material filling type.
By above-mentioned disclosed technical scheme as seen, the said method of the present invention is because at solvent With adopted the extractant identical with reaction raw materials in the separation process of water, therefore, produce This is low, the product quality height, and simultaneously, equipment investment and energy consumption are also low than prior art.
Below will relevant details of the present invention be further described by embodiment.
Embodiment 1
The aqueous acetic acid inlet amount is 4500 kilograms/hour, and its water content is 30% (wt).Being equivalent to dehydrating amount is 1350 kilograms/hour, and the inlet amount of m-xylene is 4000 kilograms/hour, corresponding to one 4.5 ten thousand tons/year m-xylene acid production equipment.The extraction agent internal circulating load is 10000 kilograms/hour.Extraction tower is φ 300 * 25000mm, and packing tower, rectifying tower are 800 * 12000mm, also is packing tower.The service temperature of extraction tower is 69 ℃, and the rectifying tower tower top temperature is 113 ℃.The result obtains, and the m-xylene content in the water is 0.008% (wt).In the material of rectifying tower top, m-xylene consist of 56% (wt), can be used as the raw material of m-xylene oxidizer.
Embodiment 2
The aqueous acetic acid inlet amount is 28000 kilograms/hour, and its water content is 28% (wt).Being equivalent to dehydrating amount is 7700 kilograms/hour, and the inlet amount of p-Xylol is 23000 kilograms/hour, corresponding to one 250,000 tons/year p-Xylol acid production equipment.The extraction agent internal circulating load is 75000 kilograms/hour.Extraction tower is φ 800 * 25000mm, and tray column, rectifying tower are 1800 * 16000mm, also is tray column.The service temperature of extraction tower is 75 ℃, and the rectifying tower tower top temperature is 116 ℃.The result obtains, and the p-Xylol content in the water is 0.009% (wt).In the material of rectifying tower top, p-Xylol consist of 53.3% (wt), can be used as the raw material of p xylene oxidation device.
Claims (5)
1. the production method of an aromatic binary carboxylic acid, comprise p-Xylol or m-xylene in acetic acid with the sepn process of oxidation reaction process, terephthalic acid or the m-phthalic acid of air and the sepn process of acetic acid and water, it is characterized in that the sepn process of acetic acid and water comprises the steps:
1. p-Xylol or m-xylene enter from the bottom of extraction tower (1), and aqueous acetic acid enters from the top of extraction tower (1), and the mixed oil phase of acetic acid and p-Xylol or m-xylene is flowed out by extraction tower (1) top, and isolated water is gone out by tower bottom flow;
The service temperature of extraction tower is 50～120 ℃.
The weight ratio of p-Xylol or m-xylene and aqueous acetic acid is: 1: (1～10);
2. enter rectifying tower (2) by the effusive acetic acid in extraction tower (1) top and p-Xylol or m-xylene mixing solutions and carry out rectifying separation, effusive from rectifying tower (2) top is the mixture of acetic acid and p-Xylol or m-xylene, Returning oxidation reactor;
What came out in rectifying tower (2) end is p-Xylol or m-xylene, enters extraction tower (1) again behind additional dimethylbenzene or the m-xylene.
2. the method for claim 1 is characterized in that, the tower top temperature of rectifying tower (2) is 113～116 ℃, and the service temperature of extraction tower is 70～80 ℃, and the ratio of p-Xylol or m-xylene and aqueous acetic acid is 1: (2～4).
3. the method for claim 1 is characterized in that, p-Xylol or m-xylene internal circulating load are 3～10 with the ratio of the weight of add-on.
4. the method for claim 1 is characterized in that, the p-Xylol or the m-xylene that come out in rectifying tower (2) end are water-cooled to 50～120 ℃.
5. the method for claim 1 is characterized in that, p-Xylol or m-xylene that comes out in rectifying tower (2) end and the acetic acid that enters rectifying tower (2) and p-Xylol or m-xylene solution carry out heat exchange and is cooled to 50～120 ℃.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN00115599A CN1097576C (en) | 2000-05-09 | 2000-05-09 | Production process of aromatic binary carboxylic acid |
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|---|---|---|---|
| CN00115599A CN1097576C (en) | 2000-05-09 | 2000-05-09 | Production process of aromatic binary carboxylic acid |
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| CN1277184A true CN1277184A (en) | 2000-12-20 |
| CN1097576C CN1097576C (en) | 2003-01-01 |
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| CN00115599A Expired - Fee Related CN1097576C (en) | 2000-05-09 | 2000-05-09 | Production process of aromatic binary carboxylic acid |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100368370C (en) * | 2006-03-29 | 2008-02-13 | 中国石化仪征化纤股份有限公司 | Recovery system of suspended substance in para dimethyl benzene oxidation mother liquor |
| CN111747843A (en) * | 2020-06-24 | 2020-10-09 | 中国石油化工股份有限公司 | Method for recovering aromatic carboxylic acid from m-phthalic acid refining wastewater |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| IT1075317B (en) * | 1977-04-13 | 1985-04-22 | Montedison Spa | METHOD FOR SOLVENT ANHYDRIFICATION AND FOR THE RECOVERY OF THE BY-PRODUCT OF METHYL ACETATE IN A SYNTHESIS PROCESS OF TEREPHTHALIC ACID |
| JP3729284B2 (en) * | 1995-09-22 | 2005-12-21 | 三菱瓦斯化学株式会社 | Method for producing high purity terephthalic acid |
-
2000
- 2000-05-09 CN CN00115599A patent/CN1097576C/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100368370C (en) * | 2006-03-29 | 2008-02-13 | 中国石化仪征化纤股份有限公司 | Recovery system of suspended substance in para dimethyl benzene oxidation mother liquor |
| CN111747843A (en) * | 2020-06-24 | 2020-10-09 | 中国石油化工股份有限公司 | Method for recovering aromatic carboxylic acid from m-phthalic acid refining wastewater |
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| CN1097576C (en) | 2003-01-01 |
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