CN105801402A - Method for removing iodine ions in acetic acid - Google Patents
Method for removing iodine ions in acetic acid Download PDFInfo
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- CN105801402A CN105801402A CN201410851609.XA CN201410851609A CN105801402A CN 105801402 A CN105801402 A CN 105801402A CN 201410851609 A CN201410851609 A CN 201410851609A CN 105801402 A CN105801402 A CN 105801402A
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Abstract
The invention belongs to the technical field of separation and purification of acetic acid, and relates to a method for removing iodine ions in acetic acid. The method includes the steps: a deiodination agent and iodine ions contained in a first acetic acid stream in a first separation device are subjected to a reaction to generate methyl iodide, and the methyl iodide comes out from the first separation device and is circulated back to the first separation device and/or a production reactor; a second acetic acid stream obtained at the bottom of the first separation device enters a second separation device and is further separated and purified. According to the method, methanol is added in a light fraction removal tower, separation of various components in the light fraction removal tower is not affected, at the same time, the content of the iodine ions in the tower bottom acetic acid is reduced, iodomethane generated from reaction of methanol and the iodine ions and original iodomethane in a process stream are distilled off from the tower top at the same time and return to the device for circulation. The method does not need for addition of a new device in a conventional process for producing acetic acid, and not only can effectively remove the iodine ions, but also does not affect separation of acetic acid and other components in the original process.
Description
Technical field
The invention belongs to acetic acid separated technical field of purification, relate to a kind of removing the method for iodide ion in acetic acid.
Background technology
Acetic acid is a kind of important basic organic chemical industry raw material, is widely used in the industries such as chemical industry, pesticide, medicine, national defence, electronics.Methyl alcohol carbonyl synthetic method is to prepare the method employed up in process of acetic acid.This technique developed by Monsanto company uses rhodium system homogeneous catalyst, and iodomethane is as auxiliary agent.This technique is optimized by British Petroleum Company (BP) and Celanese companies, develops the AOPlus technique of the Cativa technique using metal iridium as major catalyst and low water content respectively, makes acetic acid production capacity increase substantially.Although the major catalyst of two kinds of techniques is different, but iodomethane all can be used to make auxiliary agent simultaneously, AOPlus technique is especially more the use of the lithium iodide of high concentration.Therefore acetate products inevitably contains ioda matter.And when using acetic acid as raw material production downstream product, iodide often result in many catalyst poisonings inactivation.Time such as with acetic acid and ethylene synthase vinyl acetate, metal acetate salt catalyst used is just very sensitive to iodide.Therefore a kind of economically viable method ioda matter to remove in acetic acid must be found.
Ioda matter be generally with iodomethane be representative organic iodine and iodide ion.Iodomethane differs relatively big with acetic acid boiling point, is therefore removed easily via rectification in follow-up separating technology, but the elimination of iodide ion is comparatively difficult.Monsanto company has invented in the process of acetic acid rectification in patent US4039395, adds one pure methanol stream in dehydrating tower, methanol and iodide ion react by elimination, the iodomethane of generation return in process units participate in circulation.
Traditional Monsanto technique has been improved by BP company and Celanese Corp..Celanese Corp. is proposed AOplus technique, the system of rhodium series catalysts adds the inorganic iodide (mainly lithium iodide) of high concentration, improve catalyst is stability, and from 13%-15%, water content is reduced to 4%-5%, has been maintained with higher carbonylation rate.BP company is proposed Cativa technique, uses iridium as major catalyst, uses rhenium, ruthenium, osmium etc. as auxiliary agent, and water content can be low to moderate 2%, has high space-time yield simultaneously.
While catalyst is improved by both the above technique, it is respectively directed to the feature of low water content, distillation process has been improved, for instance, 3 traditional tower rectification are all simplified as two-tower rectification by patent EP0616997A1 and CN1491199A.This improvement simplifies technological process, reduces energy consumption, decreases the use of noble metal equipment and materials.
The improvement of production technology means traditional addition methanol in dehydrating tower, and in reduction acetate products, the method for iodide ion content will be no longer applicable, is badly in need of developing a kind of de-iodine method under new process conditions.
Summary of the invention
The technical problem to be solved is for the deficiencies in the prior art, it is provided that a kind of remove the method for iodide ion in acetic acid.The method is in the distillation process of methyl alcohol carbonyl synthetic acetic acid, the logistics containing methanol is added in cut light tower, make methanol and iodide ion react generation iodomethane and return to production reaction unit from lightness-removing column top, obtain the acetic acid containing extremely low iodide ion He other heavy constituent at the bottom of tower, enter in weight-removing column and further separate purification.The method need not increase new equipment in the technique of existing acetic acid processed, can either efficient removal iodide ion, do not affect again separating of acetic acid and other components in original technique.
For this, the invention provides and a kind of remove the method for iodide ion in acetic acid, including:
Step L, the iodide ion making de-iodine preparation contained with the first acetic acid stream in the first segregation apparatus reacts generation iodomethane；
Step M, iodomethane out from the first segregation apparatus and loops back the first segregation apparatus and/or produces reaction unit；
Step N, the second acetic acid stream that the first separation unit bottoms obtains enters the second segregation apparatus.
According to the present invention, described first segregation apparatus is cut light tower.Described first acetic acid stream feed entrance point is positioned at from 20-30 column plate place at the bottom of tower.Feed entrance point containing the logistics of described de-iodine preparation is positioned at from 5-25 column plate place at the bottom of tower, and lower than the first at least one block, acetic acid stream position column plate.Preferably it is positioned at from 9-17 column plate place at the bottom of tower containing the feed entrance point of the logistics of described de-iodine preparation.
In certain embodiments of the present invention, the logistics containing described de-iodine preparation is through preheating rear feeding, and the temperature of described preheating is 30-50 DEG C.The temperature of preferred described preheating is 30 DEG C.
According to the present invention, containing methanol in described de-iodine preparation, and mol ratio >=10 of methanol and iodide ion.The mol ratio of preferred methanol and iodide ion is 90-120.
In the present invention, described de-iodine preparation is pure methanol or the mixed solution containing methanol.
In some embodiments of the invention, in described pure methanol methanol content more than 99.5wt%.
In other embodiments of the present invention, the described mixed solution containing methanol is made up of with one or more in acetic acid, iodomethane, methyl acetate and water methanol, wherein mass content >=50% of methanol.
In above-mentioned elimination acetic acid in the process of iodide ion, described first segregation apparatus is cut light tower, for separating acetic acid and iodomethane, methyl acetate, water, its raw material (the first acetic acid stream) comes from flash tank, light component is (containing major part iodomethane, methyl acetate, water and a small amount of acetic acid) distillate from tower top, after condensed, a part returns to cut light tower and refluxes as tower, another part loops back production reaction unit, obtain containing a small amount of water at the bottom of tower, the acetic acid of the heavy constituents such as propanoic acid is as the second acetic acid stream, the second segregation apparatus (de-heavy oil column) is gone to separate purification further.
Described second segregation apparatus is de-heavy oil column, is used for separating acetic acid and propanoic acid and other a small amount of heavy constituents, obtains qualified acetate products, and its raw material (the second acetic acid stream) comes from the first segregation apparatus (cut light tower).
In some embodiments of the invention, described first acetic acid stream contains in mass:
The fixed gas of surplus
Wherein, described fixed gas includes CO, CO2、H2、N2And methane.
In other embodiments of the present invention, mass content >=99% of acetic acid in the second acetic acid stream.
Accompanying drawing explanation
Below in conjunction with accompanying drawing, the present invention is described.
Fig. 1 removes the process flow diagram of iodide ion in acetic acid in embodiment 1；
In figure, the implication of accompanying drawing labelling is as follows: 101 cut light tower；1 pipeline 1；2 pipelines 2；3 pipelines 3；4 condensing units；5 pipelines 5；6 pipelines 6；7 pipelines 7；11 first charging apertures；22 second charging apertures.
Detailed description of the invention
For making the present invention easier to understand, describing the present invention in detail below in conjunction with embodiment and accompanying drawing, these embodiments only play illustrative effect, it is not limited to the range of application of the present invention.
Fig. 1 removes the process flow diagram of iodide ion in acetic acid in embodiment 1.As shown in Figure 1, the first acetic acid stream containing acetic acid, methyl acetate, iodomethane, water and iodide ion is entered into cut light tower (first segregation apparatus) 101 in through pipeline 1 by the first charging aperture from flash tank, in first acetic acid stream in mass, acetic acid content is 20%-80%, methyl acetate content is typically in 10%-40%, iodomethane content is 10%-25%, and water content, at 2%-15%, contains a small amount of CO, CO simultaneously2, the on-condensible gas such as methane, the content of iodide ion depends on whole carbonylic synthesis technology, is typically between 100～2000ppm.Methanol is entered in cut light tower (the first segregation apparatus) 101 by the second charging aperture through pipeline 6 as de-iodine preparation, and iodide ion contained with the first acetic acid stream in cut light tower (the first segregation apparatus) 101 reacts generation iodomethane.Light component containing major part iodomethane, methyl acetate, water and a small amount of acetic acid distillates at the tower top of cut light tower (the first segregation apparatus) 101 through pipeline 2, after the condensation of condensed device 4, a part returns in cut light tower (the first segregation apparatus) 101 through pipeline 3 and refluxes as tower, and another part loops back in production reaction unit (not shown) through pipeline 5.The acetic acid quality content thick acetic acid more than 99% is obtained as the second acetic acid stream at the bottom of the tower of cut light tower (the first segregation apparatus) 101, deliver to de-heavy oil column (the second segregation apparatus, not shown) rectification further through pipeline 7 and obtain acetate products.
The feed entrance point of described first acetic acid stream i.e. the first charging aperture 11 is determined by the separation case of each component and technological design, generally 20-30 column plate place at the bottom of from tower.
The feed entrance point of the logistics of described de-iodine preparation i.e. the second charging aperture 22 should lower than the feed entrance point of the first acetic acid stream i.e. 11 at least one blocks of column plates of the first charging aperture, for from 5-25 column plate place at the bottom of tower.
In one preferred embodiment, the feed entrance point of the logistics of described de-iodine preparation i.e. the second charging aperture 22 is positioned at from 9-17 column plate place at the bottom of tower.
Containing methanol in described de-iodine preparation, containing methanol in described de-iodine preparation, and mol ratio >=10 of methanol and iodide ion.The mol ratio of preferred methanol and iodide ion is 90-120.Studying discovery through the present inventor, if the mol ratio of methanol and iodide ion is lower than 90, de-iodine effect is bad, higher than the circulating load of 120 loads increasing rectifying column and whole technique.
Pure methanol that described de-iodine preparation can be single use or use by methanol and one or more mixed solutions containing methanol formed in acetic acid, iodomethane, methyl acetate and water.And this pure methanol or the mixed solution containing methanol can be introduced into a part of material benzenemethanol (pure methanol) and enter in lightness-removing column (the first segregation apparatus), or (i.e. the mixed solution containing methanol) containing methanol stream satisfactory in existing synthesis acetic acid technique is introduced in lightness-removing column (the first segregation apparatus).
When using iodine preparation de-with one or more mixed solutions containing methanol the formed work in acetic acid, iodomethane, methyl acetate and water by methanol, methanol weight/mass percentage composition in mixed solution should be greater than being equal to 50%.
Some preferred embodiment in, described methanol or the mixed solution containing methanol should pass into after preheating in rectifying column, and the temperature of described preheating is 30-50 DEG C.The temperature of preferred described preheating is 30 DEG C.
Heretofore described term " production reaction unit " refers to the reaction unit for methyl alcohol carbonyl synthetic acetic acid.
The invention provides and a kind of use methanol to reduce the method for iodide ion content in acetic acid, specifically in the distillation process of methyl alcohol carbonyl synthetic acetic acid, one logistics containing methanol is added in cut light tower (the first segregation apparatus), make methanol and iodide ion react generation iodomethane and return to process units from lightness-removing column (the first segregation apparatus) top, obtain the thick acetic acid (the second acetic acid stream) containing extremely low iodide ion He other heavy constituent at the bottom of tower, enter in weight-removing column (the second segregation apparatus) and further separate purification.
Existing technique is usually in dehydrating tower and adds methanol stripper iodide ion, after acetic acid entrance weight-removing column removes heavy constituent impurity further at the bottom of tower, obtains acetate products.Therefore for avoiding introducing impurity in acetate products, in US Patent No. 4039395, de-iodine reagent used is pure methanol.
But it is different from existing technique, technique in the present invention is to add methanol or the mixed solution containing methanol in lightness-removing column, this mixed solution can be made up of with one or more in acetic acid, iodomethane, methyl acetate and water methanol, and wherein the mass content of methanol should be greater than being equal to 50%.This mixed solution carries out rectification after passing into cut light tower together with solution original in tower, neither affect the separation of each component in lightness-removing column, reduce the content of iodide ion in acetic acid at the bottom of tower simultaneously, methanol and iodide ion react the iodomethane generated and distillate from tower top with original iodomethane in process-stream simultaneously, return in device and are circulated.This methanol or the mixed solution containing methanol can be introduced into a part of material benzenemethanol and enter in lightness-removing column, or introduces satisfactory in existing synthesis acetic acid technique in rectifying column containing methanol stream.In terms of existing technologies, above-mentioned technique all achieves beyond thought effect.The method need not increase new equipment in the technique of existing acetic acid processed, can either efficient removal iodide ion, do not affect again separating of acetic acid and other components in original technique.
Embodiment
Embodiment 1-4:
Using containing acetic acid 62%, methyl acetate 20%, water 8%, iodomethane 10%, iodide ion 100ppm mixed solution be passed into continuously in the rectifying column (the first segregation apparatus) that the number of plates is 65 as the first acetic acid stream, pass into position for from the bottom of tower 25 blocks of column plates.The bottom temperature of rectifying column (the first segregation apparatus) is 118～120 DEG C, and pressure is slightly above atmospheric pressure.Pure methanol as de-iodine preparation by from 9 column plates at the bottom of tower preheated after pass in rectifying column (the first segregation apparatus).The ratio of methanol and iodide ion is adjusted, in Table 1 by changing the feed rate of methanol.Difference continuous discharge at the bottom of tower top, tower, uses chromatography of ions (wearing peace ics1100, Dai An company, the U.S.) to analyze the content of iodide ion in thick acetate products at the bottom of tower (the second acetic acid stream), in order to investigate the de-iodine effect of de-iodine preparation methanol.Table 1 lists the iodide ion content in thick acetate products (the second acetic acid stream).
Embodiment 5-6:
Except the feed entrance point of de-iodine preparation methanol, other conditions, with embodiment 1, are analyzed result and are listed in table 1.
Embodiment 7:
Using the mixed solution containing methanol that 90% methanol and 10% methyl acetate are mixed to form as de-iodine preparation, other conditions, with embodiment 1, are analyzed result and are listed in table 1.
Embodiment 8:
Using the mixed solution containing methanol that 90% methanol and 10% water are mixed to form as de-iodine preparation, other conditions, with embodiment 1, are analyzed result and are listed in table 1.
Table 1
Above example shows, use methanol or the mixed solution containing methanol as de-iodine preparation in lightness-removing column (the first segregation apparatus), can effectively removing iodide ion, in the thick acetate products (the second acetic acid stream) obtained, iodide ion content is lower than 2ppm.Do not affect the separation of each component in lightness-removing column in existing technique, do not introduce other impurity simultaneously.
Meanwhile, (the second acetic acid stream) gas chromatographic analysis of the thick acetate products in above-described embodiment is it is shown that the mass content of acetic acid is up to more than 99% in above-mentioned second acetic acid stream.
The foregoing is only presently preferred embodiments of the present invention, not in order to limit the present invention, all within the spirit and principles in the present invention, any amendment of making, equivalent replacement, improvement etc., should be included within protection scope of the present invention.
Claims (10)
1. remove a method for iodide ion in acetic acid, including:
Step L, the iodide ion making de-iodine preparation contained with the first acetic acid stream in the first segregation apparatus reacts generation iodomethane；
Step M, iodomethane out from the first segregation apparatus and loops back the first segregation apparatus and/or produces reaction unit；
Step N, the second acetic acid stream that the first separation unit bottoms obtains enters the second segregation apparatus.
2. method according to claim 1, it is characterised in that
Described first segregation apparatus is cut light tower；
Described first acetic acid stream feed entrance point is positioned at from 20-30 column plate place at the bottom of tower；
Feed entrance point containing the logistics of described de-iodine preparation is positioned at from 5-25 column plate place at the bottom of tower, and lower than the first at least one block, acetic acid stream position column plate.
3. method according to claim 2, it is characterised in that the feed entrance point containing the logistics of described de-iodine preparation is positioned at from 9-17 column plate place at the bottom of tower.
4. method as claimed in any of claims 1 to 3, it is characterised in that the logistics containing described de-iodine preparation is through preheating rear feeding, and the temperature of described preheating is 30-50 DEG C.
5. method according to claim 4, it is characterised in that the temperature of described preheating is 30 DEG C.
6. method as claimed in any of claims 1 to 3, it is characterised in that containing methanol in described de-iodine preparation, and mol ratio >=10 of methanol and iodide ion；The mol ratio of preferred methanol and iodide ion is 90-120.
7. method according to claim 6, it is characterised in that described de-iodine preparation is pure methanol or the mixed solution containing methanol.
8. method according to claim 7, it is characterised in that the described mixed solution containing methanol is made up of with one or more in acetic acid, iodomethane, methyl acetate and water methanol, wherein mass content >=50% of methanol.
9. method as claimed in any of claims 1 to 3, it is characterised in that described first acetic acid stream contains in mass:
Wherein, described fixed gas includes CO, CO2、H2、N2And methane.
10. method as claimed in any of claims 1 to 3, it is characterised in that mass content >=99% of acetic acid in the second acetic acid stream.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201410851609.XA CN105801402A (en) | 2014-12-31 | 2014-12-31 | Method for removing iodine ions in acetic acid |
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| CN201410851609.XA CN105801402A (en) | 2014-12-31 | 2014-12-31 | Method for removing iodine ions in acetic acid |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4039395A (en) * | 1975-08-11 | 1977-08-02 | Monsanto Company | Purification of acetic acid |
| JPH0640999A (en) * | 1992-06-02 | 1994-02-15 | Bp Chem Internatl Ltd | Preparation of acetic acid |
| JP2009501129A (en) * | 2005-07-14 | 2009-01-15 | ダイセル化学工業株式会社 | Method for producing carboxylic acid |
| CN102471209A (en) * | 2009-07-07 | 2012-05-23 | 塞拉尼斯国际公司 | Acetic acid production by carbonylation with enhanced reaction and flash |
-
2014
- 2014-12-31 CN CN201410851609.XA patent/CN105801402A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4039395A (en) * | 1975-08-11 | 1977-08-02 | Monsanto Company | Purification of acetic acid |
| JPH0640999A (en) * | 1992-06-02 | 1994-02-15 | Bp Chem Internatl Ltd | Preparation of acetic acid |
| JP2009501129A (en) * | 2005-07-14 | 2009-01-15 | ダイセル化学工業株式会社 | Method for producing carboxylic acid |
| CN102471209A (en) * | 2009-07-07 | 2012-05-23 | 塞拉尼斯国际公司 | Acetic acid production by carbonylation with enhanced reaction and flash |
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