CN1012954B - Process for separating residue from industrial p-phthalic acid - Google Patents
Process for separating residue from industrial p-phthalic acidInfo
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- CN1012954B CN1012954B CN 88105551 CN88105551A CN1012954B CN 1012954 B CN1012954 B CN 1012954B CN 88105551 CN88105551 CN 88105551 CN 88105551 A CN88105551 A CN 88105551A CN 1012954 B CN1012954 B CN 1012954B
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- acid
- terephthalic acid
- washing
- phthalic acid
- residue
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Abstract
The present invention relates to a method for separating industrial terephthalic acid residues. When terephthalic acid is prepared by oxidizing paraxylene, residues acting as an oxidation by-product contain various mono-acid and isomery binary-acid. The method of the present invention comprises the following steps: firstly, washing oxidation residues by water; then, carrying out a selective reaction at high temperature and under the condition that salt of weak acid exists in order to lead terephthalic acid and m-phthalic acid to be separated; in the next place, extracting the mixture by a solvent in order to lead the terephthalic acid and the m-phthalic acid to be respectively separated by the mono-acid mixed. The method of the present invention can be adopted to reduce use level of the extraction solvent, reduce energy consumption, avoid an apparatus from corroding, prevent from pollution and improve security. C07D491/04, C07D495/04, C07D521/00, C07D413/04, C07D417/04.
Description
The present invention is the separation method of relevant industrial terephthaldehyde acid residue, and specifically the residue that is produced when making terephthalic acid by p xylene oxidation carries out isolating method.
Terephthalic acid is the raw material of preparation polyester, at present general all with p-Xylol under acetate solvate and catalyst action, make through high temperature or low-temperature oxidation.Oxidation mother liquor is after solvent and catalyst recovery, and remaining oxidized byproduct and impurity just are sent to incinerator as residue and burn but.This oxidation residua contains the isomery double base acid of the unit acid of phenylformic acid (BA), paratolunitrile (P-TA), terephthalaldehydic acid (4-CBA) and so on and m-phthalic acid (iPA), terephthalic acid (TPA), phthalic acid (OPA) and so on.Wherein mixed cell acid is used as encapsulant manufacturing Synolac paint at the industrial phenylformic acid that replaces; M-phthalic acid is to be used to make modified unsaturated polyester and the only raw material of polyester coating; Terephthalic acid can be used to make the softening agent of polyvinyl chloride cable material usually.
Japan is from the seventies, and the separation method research that arises from oxidation residua is active day by day, has proposed many patent applications in succession, as the public clear 46-43222 of spy, spy open clear 48-541, the spy opens clear 48-542 etc.Its main separation method roughly has: solvent extraction process, and with oxidation translocation reaction method and nitric acid oxidation separation method.Though these separation methods have reached under certain conditions with the isolating purpose of residue, but but there are many problems respectively in industrial application, big such as the low boiling point organic solvent consumption, the energy consumption height of oxidation translocation reaction, nitric acid are to seriously corroded of equipment etc.
The objective of the invention is to provide a kind of novel method of separation industries terephthaldehyde's acid residue.Specifically before adopting solvent extraction, earlier residue is washed pre-treatment, under the condition that high temperature, salt of weak acid exist, carry out selective reaction then, make to be difficult to the acid of isolating isomery double base and at first to be separated; Adopt a small amount of solvent that mixed cell acid is separated with terephthalic acid, a benzene two single acid respectively at last.This technology can reduce the consumption of organic low boiling point solvent in a large number, reduces the energy consumption of reaction, avoids the corrosion of equipment.
Separation method of the present invention is finished in such a way.
At first the catalyzer and the small amounts of ortho phthalic acid that residue in the residue are removed by washing.Washing is to carry out in the washing still, and residue under agitation feeds intake, and the ratio of residue and water was generally 1: 3.After stirring washing in 1 hour, centrifuging, it is standby that solid phase (washing slag) enters feed bin, and water lotion flows into sewage lagoon.Through washing, can remove trace catalyst contained in the residue and small amounts of ortho phthalic acid, but also have a small amount of phenylformic acid to run off.Therefore in water washing process, need not heating, and need under certain acidic conditions (pH=2.0), to carry out, to suppress benzoic loss.The changing conditions of residue component concentration sees Table 1 before and after the washing pre-treatment.
Removed trace catalyst and small amounts of ortho phthalic acid by washing after, the most difficult isolating be m-phthalic acid, this a pair of component of terephthalic acid.Because its physics is very close with chemical property, even reach fractionation by distillation through esterification reaction of organic acid also difficulty.Therefore industrial calcium salt method commonly used comes compartment phthalic acid and terephthalic acid.Yet this calcium salt method can only not have just to reach effective separation in the presence of the 3rd component, and operation is longer, is not suitable for the separation of residue.
The present invention according to the improvement Heng Geerfa the acid out principle, i.e. more molten easy disassociation of the benzene carboxylic acid that the benzene carboxylic acid that solubleness is bigger in the water is littler than solubleness, its dissociative hydrogen ion just can carry out acid precipitation reaction, makes another benzene carboxylic acid salt by acid out.Owing to contain a large amount of phenylformic acid in the commercial terephthalic acid residue, and m-phthalic acid salt has bigger solvability than terephthalate in water.Therefore as long as adding a certain amount of alkali in reaction system just can reach and make m-phthalic acid salt be dissolved in the purpose of liquid phase, and terephthalic acid still is present in solid phase with the form of acid, thereby reaches isolating purpose.
This selectivity acid-base reaction method must have the benzene carboxylic acid salt of solubility to exist.The effect that the buffer pH value changes is played in the effect of the existing acid out agent of the phenylformic acid in the reaction system again, selectivity acid-base reaction between m-phthalic acid and the terephthalic acid is remained in certain pH value scope carry out.
The pH value scope of above-mentioned selectivity acid-base reaction is generally pH(4.0～5.0), preferably between (4.2～4.5).The pH value rises, and the amount of bringing terephthalic acid in the liquid phase into is increased; The pH value descends, and then the residual content of m-phthalic acid increases in the solid phase.The pH value is directly added the influence of alkali number simultaneously, and adds the content of how many knacks of alkali number m-phthalic acid in residue.The present invention has determined that through experiment screening repeatedly with m-phthalic acid neutralization equivalent coefficient 1.2～1.5 be optimum coefficient.
To add NaOH is example, and its calculating formula is as follows:
The NaOH(kilogram)=G * ipA% ÷ 83 * 40 * η
G in the formula: the charging capacity of commercial terephthalic acid residue (kilogram)
83: the m-phthalic acid kilogram equivalent
40: the sodium hydroxide kilogram equivalent
η: optimum coefficient
The temperature of the soda acid selective reaction among the present invention is generally 130 ℃, and in 2 hours reaction times, be 1 through the residue (washing slag) of washing and the ratio of water: 3(weight), the concentration of used NaOH is about 10%.
After the reaction, m-phthalic acid enters in a large number and is neutralized dissolving after the solid m material (m-phthalic acid that contains unit acid) of acid out only has about 5% to be present in not by the solid I material of alkali neutral.90 ℃ of acid hot wash secondaries of available pH2.0 are promptly separated out unit acid and m-phthalic acid after the resulting washing lotion cooling at this moment, merge with solid m material.Solid (washing) material main ingredient that stays is terephthalic acid and other unit acid.Washing slag component concentration and the solid m after the selectivity acid-base reaction, solid I material component content see Table 2.
Solid (washing) material component content and solid I material component content after the acid hot wash see Table 3.
Mainly contain mixed cell acid and m-phthalic acid through the resulting solid m material of above-mentioned selective reaction, the present invention adopts the benzene of organic low boiling point solvent to carry out the extracting separation, the benzene solvent extracting is to carry out in airtight extracting still, makes unit acid dissolving under certain temperature and pressure condition.The present invention adopts the extracting of secondary benzene solvent, primary solid m/ benzene=1/4(weight), be 1/3 for the second time.Extraction temperature is 125 ℃, pressure 5.5Kg/ square centimeter, and extracting was filtered under normal pressure after 2 hours, and the gained solid-phase material is m-phthalic acid.Liquid phase flows into the solvent evaporation still, with vapor distillation benzene is steamed, and recycles after the condensation, and the solid of separating out is mixed cell acid.
Gu (washing) material mainly contains mixed cell acid and terephthalic acid, the present invention adopts methyl alcohol as extraction solvent.Sepn process is similar with separating of solid m material, and just temperature of reaction is 80 ℃, and the liquid phase after the filtration need be through decolouring, and solid phase also needs to clean impurity through hot water.The purity of the mixed cell acid that obtains after the above-mentioned extracting of process, m-phthalic acid, terephthalic acid sees Table 4.
Adopt commercial terephthalic acid process for separating residue provided by the present invention, owing at first residue is washed pre-treatment, carry out the soda acid selective reaction then, terephthalic acid and m-phthalic acid have been separated, so when last solvent extraction, the consumption of organic low boiling point solvent can significantly reduce.In addition, the reaction conditions gentleness of soda acid selective reaction need not strong acid, highly basic, so can effectively cut down the consumption of energy, avoids the corrosion of equipment, and separation costs is descended significantly.Therefore method provided by the present invention is for separation of great value improvement beyond doubt of commercial terephthalic acid residue.
Embodiment:
300Kg process water (being adjusted to pH=2.0 with sulfuric acid) is joined in the washing still in advance, under agitation drop into commercial terephthalic acid residue 100Kg.Wash blowing after a hour, filter, dry through ψ 600mm tripod pendulum type batch centrifugal.Washing lotion is gone into sewage lagoon, and it is standby that the washing slag enters feed bin.
In the selective reaction still, add a certain amount of water in advance, under agitation drop into 50Kg washing slag (being converted to butt), and be adjusted to solid-liquid=1/3.Be warmed up to 130 ℃, inject 10% NaOH58.9Kg gradually with volume pump, injection in about 2 hours finishes, and keeps 130 ℃ to be cooled to 50 ℃ then in 1 hour, and blowing, filtration (suction filtration) are with hot water injection's reactor perisporium.Filtrate and washing lotion flow into mother liquor tank in the lump, 50 ℃ through decolorizing with activated carbon, flow into crystallizer.Liquid phase in the crystallizer is heated to 90 ℃, adds 10% sulfuric acid gradually, acid out is incubated 4 hours with pH value of solution 2.0, cools off then, filters.Filtrate enters sour water basin (for cycling use of water), and solid is solid m material.Then with the solid I material after the aforementioned filtration,, wash and get thing and separate out washing more than 90 ℃ 2 times with pH2.0 sour water (cycling use of water) through cooling, merge with solid m material.The solid that stays is solid (washing) material.
The solid m material (butt) of 25Kg is put in the extracting still, added the benzene of 100Kg.Stir in confined conditions and be warmed up to 125 ℃, be incubated 1 hour, be cooled to 85 ℃ then, stop to stir.Treat solid-liquid two phase stratification in the still, utilize to press in the residue liquid phase is extruded from siphon pipe, flow into the solvent evaporation still.Again add 75Kg benzene again, repeat aforesaid operations.Then material is put into strainer, the filtration of bleeding, and use the steaming out filter cake, residual benzene eliminates in material, promptly obtains m-phthalic acid.Filtrate and steam flow into the solvent evaporation still in the lump, with vapor distillation method benzene are steamed, and send into the benzene solvent jar after the condensation and reuse, and water in the evaporating kettle and material promptly obtain mixed cell acid after filtration.
Solid (washing) material (butt) of 25Kg is put in the solvent extraction still, add methyl alcohol 100Kg, stir in confined conditions, be warmed up to 80 ℃, be incubated 1 hour, be cooled to 65 ℃ then, stop to stir and treat in the still behind the solid-liquid two phase stratification, utilize to press in the residue liquid phase is extruded from siphon pipe, flow into bleacher (activated carbon or carclazyte), flow into the solvent evaporation still again.Again add methyl alcohol 75Kg, repeat aforesaid operations.Then material is put into strainer, the filtration of bleeding, and use the steaming out filter cake, alcohol residual in material eliminates.At last filter cake is washed several times (removing the painted thing of part) under 100 ℃ of hot water, promptly obtain terephthalic acid.Filtrate and water flow into the solvent evaporation still in the lump, and methyl alcohol is sent into the repeated use of methanol solvate basin after distilling, and water in the evaporating kettle and material promptly obtain mixed cell acid after filtration.The material composition of each operation process becomes to see Table 5 with group of products.
Table 1
Numbered samples B component A P-TA 4.CBA iPA TPA OPA
1 washing preceding 40.1 19.86 3.18 18.03 17.83 0.87
Washing back 38.92 20.37 3.32 18.79 18.56
2 washings preceding 36.12 25.47 7.07 16.86 13.88 0.55
Washing back 34.13 26.87 6.89 17.47 14.59
3 washings preceding 36.22 19.17 4.23 19.36 19.49 1.21
Washing back 34.75 19.39 4.2 20.6 20.98
Table 2 %
Numbered samples B component A P-TA 4.CBA iPA TPA
1 washing slag 38.92 20.37 3.32 18.79 18.56
Gu I 26.5 26.02 3.73 11.8 31.95
Gu m 42.72 6.87 2.32 47.07 1.01
2 washing slags 34.13 26.87 6.89 17.47 14.59
Gu I 26.93 44.74 5.51 3.82 19.54
Gu m 37.08 6.79 2.79 51.81 1.34
3 washing slags 34.75 19.39 4.2 20.6 20.98
Gu I 37.93 28.39 2.53 5.1 25.94
Gu m 22.74 5.35 1.6 69.18 1.13
4 washing slags 49.91 12.27 0.88 26.18 10.75
Gu I 58.46 18.83 1.03 1.49 20.19
Gu m 46.86 4.62 1.23 47.16 0.14
Table 3 %
Numbered samples B component A P-TA 4.CBA iPA TPA
1 solid I 26.5 26.02 3.73 11.8 31.95
(Gu washing) 16.7 38.82 8.11 0.67 35.7
2 solid I 37.93 28.39 2.53 5.1 25.94
(Gu washing) 23.1 39.43 4.51 0.65 32.21
3 solid I 26.93 44.74 5.51 3.28 19.54
(Gu washing) 16.84 47.05 5.6 1.2 29.31
4 solid I 58.46 18.83 1.03 1.49 20.19
(Gu washing) 40.02 24.85 1.87 0.32 32.94
Table 4 %
Numbered samples B component A P-TA 4.CBA iPA TPA
1 iPA 1.99 0.78 0.86 95.3 1.07
Mixed cell acid 78.44 17.16 2.1 1.36 0.76
2 iPA 1.97 0.67 0.32 95.73 1.24
Mixed cell acid 77.25 16.29 4.15 1.93 0.38
3 TPA 0.17 2.55 0.55 0.98 95.75
Mixed cell acid 29.37 61.74 7.3 1.19 0.33
4 TPA 0.43 2.6 0.54 0.97 95.46
Mixed cell acid 30.52 59.85 7.98 0.96 0.42
Table 5 %
Numbered samples B component A P-TA 4.CBA iPA TPA OPA
1 residue 36.12 25.47 7.07 16.86 13.88 0.55
2 washing slags 34.13 26.87 6.89 17.47 14.59
3 solid m 22.74 5.35 1.6 69.18 1.13-
4 solid I 34.18 28.53 2.33 3.45 31.48-
5 solid (washing) 23.87 31.94 4.16 0.72 39.31-
6 iPA 1.75 0.58 0.81 95.23 1.63 -
7 TPA 0.43 2.44 1.58 0.34 95.21 -
8 mixed cells acid 54.51 37.8 5.53 1.57 0.35-
Charging capacity 50Kg, yield 47.16Kg, the rate of recovery reaches 94.32%.
Claims (2)
1, a kind of separation method of commercial terephthalic acid residue, it is characterized in that through washing pretreated crude terephthalic acid residue, under the condition of 120～150 ℃ high temperature and salt of weak acid existence, carry out selective reaction, adding a certain amount of alkali in this reaction system, is 4.0～5.0 with the range regulation of pH value, and terephthalic acid is separated with m-phthalic acid, carry out extracting with solvent then, mixed cell acid is separated with terephthalic acid, m-phthalic acid respectively.
2, the separation method of commercial terephthalic acid residue according to claim 1 is characterized in that adopting benzene as extraction solvent when mixed cell acid separates with m-phthalic acid; When separating with terephthalic acid, mixed cell acid adopt methyl alcohol as extraction solvent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88105551 CN1012954B (en) | 1988-07-19 | 1988-07-19 | Process for separating residue from industrial p-phthalic acid |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88105551 CN1012954B (en) | 1988-07-19 | 1988-07-19 | Process for separating residue from industrial p-phthalic acid |
Publications (2)
| Publication Number | Publication Date |
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| CN1034363A CN1034363A (en) | 1989-08-02 |
| CN1012954B true CN1012954B (en) | 1991-06-26 |
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| CN 88105551 Expired CN1012954B (en) | 1988-07-19 | 1988-07-19 | Process for separating residue from industrial p-phthalic acid |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103121938B (en) * | 2011-11-18 | 2015-10-21 | 中国石油化工股份有限公司 | The treatment process of the m-phthalic acid after hydrofining |
| CN104098463B (en) * | 2014-06-16 | 2015-11-11 | 北京化工大学 | A kind of separation method of benzene polycarboxylic acid's isomers |
| CN104844445B (en) * | 2015-03-27 | 2017-06-20 | 中国昆仑工程有限公司 | The method of recovery of acetic acid from PTA thin film evaporator blanking residues |
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