CN1872830A - Method for purifying methacrylic acid - Google Patents
Method for purifying methacrylic acid Download PDFInfo
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- CN1872830A CN1872830A CN 200610028499 CN200610028499A CN1872830A CN 1872830 A CN1872830 A CN 1872830A CN 200610028499 CN200610028499 CN 200610028499 CN 200610028499 A CN200610028499 A CN 200610028499A CN 1872830 A CN1872830 A CN 1872830A
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- methacrylic acid
- discoloring agent
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- aldehyde
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Abstract
This invention provides a method for purifying methacrylic acid. The method can effectively remove microcontent impurities such as Cu and aldehyde, thus realizing the purification and decoloring of methacrylic acid. The method comprises adding a decoloring agent during methacrylic acid purification process, which can react with the impurities to form high boiling point substances that can be removed with the heavy weight components. The color degree of the product is lower than 10.
Description
Technical field
The present invention relates to a kind of method of from the crude methacrylic acid that catalytic gas phase oxidation iso-butylene or the trimethyl carbinol obtain, removing impurity such as aldehyde, ketone, reach and purify and the purpose of decolouring.
Background technology
The method of catalytic gas phase oxidation iso-butylene or trimethyl carbinol production methacrylic acid is on the books in some patents, this method is compared with traditional acetone cyanohydrin method, have advantages such as raw material sources are wide, the three wastes are few, production cost is low, have remarkable economic efficiency.Utilize in the reactant gases product that this synthetic method obtains except that the target product methacrylic acid, also contain a certain amount of by product, acetaldehyde, 1 for example, 4-dimethyl diketone, furfural, phenyl aldehyde, toxilic acid, propionic acid, isopropylformic acid, phenylformic acid, terephthalic acid, acetic acid and vinylformic acid etc.These impurity can influence the purity and the colourity of product, and particularly wherein micro-furfural and 1, foreign pigments such as 4-dimethyl diketone make the methacrylic acid product appearance be yellow, utilize traditional rectificating method can not remove these micro-foreign pigments effectively.
Solve at present that crude methacrylic acid is purified and the method for decolouring mainly be by add some can with the compound of impurity generation chemical reactions such as the aldehyde of trace and ketone, reach the purpose of purifying and decolouring, for example add a certain amount of aromatic diamine (CN 88104811.9), hydrosulphite (JP 252446/1985), mercaptan (JP6635/1985) or Resorcinol, naphthyl alcohol compounds such as (JP 130546/1985), yet effect is unsatisfactory.The removal of impurity effect of aromatic diamine is general, and costs an arm and a leg, and toxicity is big, is unfavorable for a large amount of uses.The removal of impurity poor effect of hydrosulphite and mercaptan must be used in a large number, and such discoloring agent can cause pollution for the second time, makes purification process complicated more.In addition, phenols such as Resorcinol and naphthyl alcohol discoloring agent only just has the effect of impurity such as removing aldehyde and ketone in the presence of strong acid material such as sulfuric acid or hydrochloric acid.
The invention provides a kind of methacrylic acid product is played and purify and the method for decolouring, this method can be removed impurity such as the micro-aldehyde that contains in the crude methacrylic acid, ketone simply and effectively, makes colourimetric number＜10 of methacrylic acid product.
Summary of the invention
The present invention is achieved through the following technical solutions:
With the iso-butylene or the trimethyl carbinol is raw material through the methacrylic acid that generates after the two-stage catalytic oxidation and the gaseous mixture of other by product, absorb through supercooled water, with solvent the methacrylic acid in the aqueous solution is extracted again, enter the rectification and purification device of methacrylic acid then.Refining purifying plant of the present invention comprises the desolventizing tower, takes off light component tower, takes off the heavy component tower.
In treating process, add at least a oxammonium hydrochloride, oxammonium sulfate, the Padil, 1 of being selected from, 2-quadrol, 1,2-propylene diamine, 1,3-propylene diamine, hydrazine hydrate, methyl hydrazine and 2-monoethanolamine discoloring agent, the impurity generation chemical reactions such as aldehyde, ketone by discoloring agent and trace reach purifies and the purpose of decolouring.Discoloring agent excessive in the rectifying will generate solid residue with the methacrylic acid-respons, and for continuous rectification, the amount of tower still solid residue certainly will be cumulative, and final influence is normal produces.The present invention is by bubbling air or oxygen continuously in the tower still bottom that adds discoloring agent, make it with the discoloring agent acting in conjunction in tower bottoms, can eliminate or reduce the generation of tower still solid residue, thus carrying out smoothly of guaranteeing to produce.
When the present invention makes with extra care the purification crude methacrylic acid, add in the charging of any rectifying tower that discoloring agent can be in rectification flow, but in order to reach the ideal refining effect, reduce the consumption that adds discoloring agent simultaneously, add in the charging of taking off heavies column preferably that (this feed liquid has been removed light component, for example acetaldehyde, acetone, acetic acid, vinylformic acid and isopropylformic acid etc.), take off heavy component Tata still temperature and remain on 80～100 ℃, impurity such as discoloring agent and aldehyde, ketone can be finished chemical reaction at short notice like this.In addition, in order to prevent polymerization, need to add stoppers such as quinhydrones or thiodiphenylamine in the crude methacrylic acid treating process.
Description of drawings
Fig. 1 is the process flow diagram of the method for purification of methacrylic acid of the present invention.Number in the figure is represented: 1-desolventizing tower, 2-take off light component tower, and 3-takes off the heavy component tower.
Embodiment
The purification process of the methacrylic acid that the present invention narrated is: at first utilize organic solvent that the methacrylic acid in the methacrylic aqueous acid is extracted, the gained extraction phase enters desolventizing tower [1], removes most solvent; The feed liquid of desolventizing tower [1] tower still enters takes off light component tower [2], removes remaining light component in taking off light component tower [2]; The discoloring agent that takes off light component tower [2] tower bottoms and adding enters together and takes off heavy component tower [3], impurity such as the aldehyde under the condition of heating in discoloring agent and the feed liquid, ketone react, simultaneously bubbling air or oxygen continuously in the still liquid are with the generation of insolubles at the bottom of the minimizing still.The high boiling substance that the reaction of impurity such as discoloring agent and aldehyde, ketone generates is discharged with the heavy component in tax heavy component tower [3] the tower still, and the methacrylic acid product is by the cat head extraction.
To be illustrated implementation process of the present invention with specific embodiment below, but scope of invention is not so limited.In these embodiments, per-cent all is meant weight ratio, except as otherwise noted.
Embodiment 1～4 (batch distillation)
The resulting reactant gases of the catalytic gas phase oxidation trimethyl carbinol obtains the methacrylic aqueous acid, again with carrying out rectifying after the solvent extraction after overcooling, absorption.Getting 500g respectively, to take off light component tower [2] tower still feed liquid be raw material, adds the discoloring agent that accounts for raw material total amount 0.1%, mixture entered take off heavy component tower [3] and carry out rectification under vacuum, and tower still temperature is 90 ℃, before and after the distillation in the feed liquid foreign matter content as shown in table 1.Distillation back product colourity is greater than 50 when not adding discoloring agent.After adding the discoloring agent distillation, can remove impurity such as aldehyde nearly all in the crude methacrylic acid, ketone, the colourimetric number of product＜10.
Table 1 adds foreign matter content and product colourity (unit: ppm) in the feed liquid of different discoloring agent distillations front and back
| Title | Raw material | Comparative example 1 | Embodiment 1 | Embodiment 2 | Embodiment 3 | Embodiment 4 |
| Impurity | Crude methacrylic acid | Do not add discoloring agent | 1 | 1, the 2-propylene diamine | 1, the 3-propylene diamine | Hydrazine hydrate |
| Acetaldehyde | 20 | 17 | ≤1 | ≤1 | ≤1 | ≤1 |
| Acetone | 38 | 35 | 2 | 3 | 3 | 2 |
| 1, the 4-dimethyl diketone | 50 | 30 | ≤1 | ≤1 | ≤1 | ≤1 |
| Propenal | 88 | 80 | ≤1 | ≤1 | ≤1 | ≤1 |
| Furfural | 47 | 52 | 2 | 3 | 2 | 2 |
| Phenyl aldehyde | 50 | 55 | ≤1 | ≤1 | ≤1 | 2 |
| Isopropylformic acid | 280 | 310 | 280 | 260 | 250 | 257 |
| The high boiling point component | 6112 | 270 | 260 | 240 | 250 | 270 |
| Level of residue, g | - | 2.53 | 4.1 | 4.3 | 4.2 | 4.3 |
| Product colourity | - | ＞50 | ＜10 | ＜10 | ＜10 | ＜10 |
Embodiment 5～8 (batch distillation)
Carry out rectification under vacuum by embodiment 1 identical method, difference is to change in the rectifying consumption (the discoloring agent consumption is the multiple of total impurities such as aldehyde, ketone) of discoloring agent 1, and the content of impurity is as shown in table 2 in the feed liquid of distillation front and back.
The data of comparison sheet 2 as can be known, the amount that adds discoloring agent is during greater than 10 times of total impurities such as aldehyde, ketone, can remove impurity such as aldehyde in the product, ketone substantially fully, product colourimetric number＜10.
Table 2 discoloring agent 1 consumption is to the influence (unit: ppm) of foreign matter content and product colourity in the feed liquid before and after the distillation
| Title | Raw material | Comparative example 1 | Embodiment 5 | Embodiment 6 | Embodiment 7 | Embodiment 8 |
| Impurity | Crude methacrylic acid | Do not add discoloring agent | 1 times | 5 times | 10 times | 20 times |
| Acetaldehyde | 20 | 17 | 10 | 5 | ≤1 | ≤1 |
| Acetone | 38 | 35 | 25 | 10 | 3 | 2 |
| 1, the 4-dimethyl diketone | 50 | 30 | 20 | 10 | ≤1 | ≤1 |
| Propenal | 88 | 80 | 50 | 20 | ≤1 | ≤1 |
| Furfural | 47 | 52 | 30 | 10 | 2 | 2 |
| Phenyl aldehyde | 50 | 55 | 30 | 13 | ≤1 | 2 |
| Isopropylformic acid | 280 | 310 | 275 | 265 | 255 | 257 |
| The high boiling point component | 6112 | 270 | 260 | 245 | 254 | 270 |
| Level of residue, g | - | 2.53 | 2.8 | 3.5 | 4.2 | 5.3 |
| Product colourity | - | ＞50 | 30 | 20 | ＜10 | ＜10 |
Embodiment 9～12 (batch distillation)
Carry out rectification under vacuum by embodiment 1 identical method, difference is to change takes off heavy component tower [3] tower still temperature, and the content of impurity is as shown in table 3 in the feed liquid of distillation front and back.
The data of comparison sheet 3 when tower still temperature during greater than 80 ℃, can be removed impurity such as aldehyde in the product, ketone, product colourimetric number＜10 as can be known substantially fully.Along with the rising of tower still temperature, the polymerization of still liquid tendency increases, so tower still temperature should be less than 100 ℃.
Table 3 tower still temperature is to the influence (unit: ppm) of foreign matter content in the feed liquid before and after the distillation
| Title | Raw material | Comparative example 1 | Embodiment 9 | Embodiment 10 | Embodiment 11 | Embodiment 12 |
| Impurity | Crude methacrylic acid | Do not add discoloring agent | 75℃ | 80℃ | 90℃ | 100℃ |
| Acetaldehyde | 20 | 17 | 15 | ≤1 | ≤1 | ≤1 |
| Acetone | 38 | 35 | 20 | 3 | 2 | 2 |
| 1, the 4-dimethyl diketone | 50 | 30 | 15 | 2 | ≤1 | ≤1 |
| Propenal | 88 | 80 | 45 | ≤1 | ≤1 | ≤1 |
| Furfural | 47 | 52 | 40 | 3 | 2 | 2 |
| Phenyl aldehyde | 50 | 55 | 35 | 2 | ≤1 | ≤1 |
| Isopropylformic acid | 280 | 310 | 275 | 260 | 251 | 257 |
| The high boiling point component | 6112 | 270 | 220 | 245 | 254 | 272 |
| Level of residue, g | - | 2.53 | 4.0 | 4.1 | 4.2 | 4.3 |
Embodiment 13～16 (batch distillation)
Carry out rectification under vacuum by embodiment 1 identical method, difference is toward taking off bubbling air at the bottom of the still of heavy component tower [3], corresponding to embodiment 1～4, before and after the distillation in the feed liquid content of impurity as shown in table 4.
The data of comparison sheet 4 as can be known, add behind the discoloring agent again bubbling air then level of residue almost do not increase, and can remove impurity such as aldehyde nearly all in the crude methacrylic acid, ketone, product colourimetric number＜10 equally.
Foreign matter content (unit: ppm) in the feed liquid before and after table 4 distillation
| Title | Raw material | Comparative example 1 | Embodiment 13 | Embodiment 14 | Embodiment 15 | Embodiment 16 |
| Impurity | Crude methacrylic acid | Do not add discoloring agent | 1 | 1, the 2-propylene diamine | 1, the 3-propylene diamine | Hydrazine hydrate |
| Acetaldehyde | 20 | 17 | ≤1 | ≤1 | ≤1 | ≤1 |
| Acetone | 38 | 35 | 3 | 3 | 2 | 2 |
| 1, the 4-dimethyl diketone | 50 | 30 | 2 | 2 | ≤1 | ≤1 |
| Propenal | 88 | 80 | ≤1 | ≤1 | ≤1 | ≤1 |
| Furfural | 47 | 52 | 2 | 3 | 2 | 2 |
| Phenyl aldehyde | 50 | 55 | ≤1 | ≤1 | ≤1 | 1 |
| Isopropylformic acid | 280 | 310 | 275 | 265 | 260 | 267 |
| The high boiling point component | 6112 | 270 | 250 | 247 | 255 | 258 |
| Level of residue, g | - | 2.53 | 2.51 | 2.57 | 2.53 | 2.52 |
| Product colourity | - | ＞50 | ＜10 | ＜10 | ＜10 | ＜10 |
Embodiment 17～20 (continuous still battery)
Carry out rectification under vacuum by embodiment 1 identical method, difference is to carry out continuous rectification, and the charging flow velocity is 1kg/hr, takes off continuous discharging at the bottom of the cat head, tower of heavy component tower [3], and the composition of feed liquid impurity is as shown in table 5 in the continuous process of distillation.Obviously, by adding discoloring agent, under the situation of continuous rectification, can reach the purpose of purification, decolouring equally.
The composition of feed liquid impurity and product colourity (unit: ppm) in table 5 continuous still battery
| Title | Raw material | Comparative example 1 | Embodiment 17 | Embodiment 18 | Embodiment 19 | Embodiment 20 |
| Impurity | Crude methacrylic acid | Do not add discoloring agent | 1 | 1, the 2-propylene diamine | 1, the 3-propylene diamine | Hydrazine hydrate |
| Acetaldehyde | 20 | 17 | ≤1 | ≤1 | ≤1 | ≤1 |
| Acetone | 38 | 35 | 1 | 2 | 3 | 2 |
| 1, the 4-dimethyl diketone | 50 | 30 | 1 | 2 | ≤1 | ≤1 |
| Propenal | 88 | 80 | ≤1 | ≤1 | ≤1 | ≤1 |
| Furfural | 47 | 52 | 2 | 2 | 3 | 2 |
| Phenyl aldehyde | 50 | 55 | ≤1 | ≤1 | ≤1 | 2 |
| Isopropylformic acid | 280 | 310 | 270 | 265 | 268 | 263 |
| The high boiling point component | 6112 | 270 | 250 | 245 | 255 | 265 |
| Product colourity | - | ＞50 | ＜10 | ＜10 | ＜10 | ＜10 |
Claims (4)
1, a kind of method of purification of methacrylic acid, it is characterized in that methacrylic acid gaseous mixture by catalytic gas phase oxidation iso-butylene or trimethyl carbinol production, through obtaining crude methacrylic acid liquid after water absorption and the extraction, the stopper quinhydrones or the phenothiazine that add 200ppm, and then this thick product made with extra care purification, and will be selected from oxammonium hydrochloride, oxammonium sulfate, Padil, 1, the 2-quadrol, 1, the 2-propylene diamine, 1, the 3-propylene diamine, hydrazine hydrate, at least a discoloring agent in methyl hydrazine or the 2-monoethanolamine joins in the charging of arbitrary rectifying tower, impurity aldehyde and ketone and the discoloring agent high boiling substance that generates that reacts is stayed the tower still, and cat head obtains the methacrylic acid product of high purity and colourimetric number＜10.
2, method according to claim 1 is characterized in that being present in impurity aldehyde and ketone in the crude methacrylic acid with respect to 1mol, adds discoloring agent by the amount of 10～50mol.
3, method according to claim 1 is characterized in that carrying out decompressing and continuous or batch fractionating after discoloring agent joins in the crude methacrylic acid, and tower still temperature is 80～100 ℃.
4, method according to claim 1 need be toward continuous bubbling air or oxygen in the tower still feed liquid that adds discoloring agent when it is characterized in that rectifying, and the inhibition tower bottoms produces insolubles because of the adding of discoloring agent.
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| CNB2006100284992A CN100554237C (en) | 2006-06-30 | 2006-06-30 | A kind of method of purification of methacrylic acid |
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| CNB2006100284992A CN100554237C (en) | 2006-06-30 | 2006-06-30 | A kind of method of purification of methacrylic acid |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104557511A (en) * | 2015-01-24 | 2015-04-29 | 淄博市兴鲁化工有限公司 | Method for recovering acrylic acid from acrylic acid water |
| CN111333490A (en) * | 2020-04-13 | 2020-06-26 | 江西天新药业股份有限公司 | Method for removing butyraldehyde impurities in ethanol |
| CN113512014A (en) * | 2021-08-06 | 2021-10-19 | 中触媒新材料股份有限公司 | Method for purifying epoxypropane containing aldehyde impurities |
-
2006
- 2006-06-30 CN CNB2006100284992A patent/CN100554237C/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104557511A (en) * | 2015-01-24 | 2015-04-29 | 淄博市兴鲁化工有限公司 | Method for recovering acrylic acid from acrylic acid water |
| CN111333490A (en) * | 2020-04-13 | 2020-06-26 | 江西天新药业股份有限公司 | Method for removing butyraldehyde impurities in ethanol |
| CN111333490B (en) * | 2020-04-13 | 2023-01-03 | 江西天新药业股份有限公司 | Method for removing butyraldehyde impurities in ethanol |
| CN113512014A (en) * | 2021-08-06 | 2021-10-19 | 中触媒新材料股份有限公司 | Method for purifying epoxypropane containing aldehyde impurities |
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| CN100554237C (en) | 2009-10-28 |
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Effective date of registration: 20170209 Address after: 201424 Fengxian District Cang Road, lane, Lane 357, room 100, room 295 Patentee after: Shanghai Hua Yi new material Co., Ltd Address before: 200137 Pudong North Road, Shanghai, No. 2031, No. Patentee before: Shanghai Huayi Acrylic Acid Co., Ltd. |
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