• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    PURPOSE:To recover acrylic acid efficiently by heat decomposition of acrylic acid dimer or polymer which is concentrated in the solution at the bottom of the acrylic acid distillation tower used in the last stage of the formation of an acrylic acid by the gaseous catalytic oxidation of, e.g. propylene. CONSTITUTION:The gas containing acrylic acid formed by the gaseous catalytic oxidation of propylene or acrolein is led into the distillation tower 2, and the solution at the bottom of the acrylic acid distillation tower is heated to distill out acrylic acid. Then the acrylic acid dimer existing in the residual solution and hydroquinone used as a polymerization inhibitor are heated at the evaporator 7 to decompose the acrylic acid dimer into acrylic acid. A part of the solution taken out is recycled into the evaporator and the remaining part is treated in the evaporator 16 of the second step in the same way as in the first step to separate hydroquenone and to recover acrylic acid. EFFECT:Considerably increases the yield of the purification of acrylic acid and lowers the cost of the expensive hydroquinone used as polymerization inhibitor.
    公开号:SU1169528A3
    申请号:SU792713493
    申请日:1979-01-18
    公开日:1985-07-23
    发明作者:Баба Масао；Окане Митито；Сато Такахиса
    申请人:Ниппон Шокубаи Кагаку Когио Ко.,Лтд (Фирма)；
    IPC主号:
    专利说明:

    This invention relates to an improved method for isolating acrylic acid, in particular, to isolating acrylic acid from a dinar or trimer of acrylic acid obtained in the process of producing acrylic acid, simultaneously with hydroquinone and associated with a method for isolating acrylic acid together with hydroquinone, according to which acrylic acid oligomers which are by-products in the production of acrylic acid by the reaction of catalytic oxidation in the vapor phase of propylene or acrolein and are concentrated to oic liquid rectification column to the last stage of acrylic acid is thermally decomposed for efficient regeneration of them to acrylic acid, together with hydroquinone, which is used as the polymerization in step and distillation is concentrated in the distillation bottoms lsidkosti colo us to recover acrylic acid.
    Acrylic acid is obtained by the catalytic vapor phase oxidation of propylene or acryleine with a gas containing molecular oxygen. This method consists of an oxidation stage, a stage of selection of the product of the reaction by oxidation by water absorption to obtain an aqueous solution of the product, a stage of removing water from the aqueous solution by extracting acrylic acid with an extracting solvent such as ethyl acetate, ethyl acrylate, and a stage of separating pacifier J of the secondary acetic acid stage stages of purification of acrylic acid L1 J
    Acrylic acid is known to polymerize easily. Therefore, at these stages, there is a tendency for the formation of its polymer in the apparatus, especially in the corresponding distillation columns, which often interferes with the operation of the apparatus and thus leads to a decrease in the yield of acrylic acid, which is a product of the process. To avoid this, the method of inhibiting the polymerization of acrylic acid, a method of adding inhibitors at certain stages, especially in absorption and distillation columns, is used. Hydroquinone is used as a typical polymerization inhibitor, usually in combination with another
    an effective polymethyst complexion and copper salicylate).
    Acrylic acid undergoes not only polymerization, but also oligomerization (dimerization and trimerization).
    The formation of acrylic acid dimer by dimerization of acrylic acid is significantly affected by temperature and contact time, and the fact that dimerization is almost always impossible to completely suppress by adding these polymerization inhibitors. That is, the formation of acrylic acid dimer depends on the temperature and time of contact. A decrease in the heating temperature or the contact time at the stage of the distillation of acrylic acid leads to the formation of 1-5 wt, acrylic acid dimer. (The acrylic acid dimer thus erupted and the added polymerization inhibitors are concentrated in the appropriate steps and collected in the last stage of the distillation column to levels that are 10-50 times higher than the initial concentrations, respectively.
    The release of bottom fluid containing acrylic acid dimer and polymerization inhibitors at such high concentrations is not very profitable from an economic point of view.
    Several methods are known for using bottom fluid to decompose an acrylic acid dimer into acrylic acid for further enhancement. A known method for the decomposition of polymeric materials for the isolation of acrylic acid by thermally treating a bottom liquid in the presence of a catalyst, such as a secondary amine, tertiary amine or tertiary phosphine.
    There is also known a method for separating acrylic acid by evaporating the bottoms of a distillation column in an evaporator with passing the resulting steam containing acrylic acid dimer through a heated steel pipe in which the dimer undergoes decomposition reaction. However, these methods are not satisfactory because the maximum degree is in the base. acid is 60-80 wt.%, even if the processes are carried out on a laboratory scale, and will be practically even lower, as a large amount of high viscous residue. The closest in technical essence to the present invention is a method for separating acrylic acid from the bottom liquid of a distillation column, in which the distillation column distillation column is evaporated in an evaporator to a level of 60-80% at a temperature above and an overpressure, and the polymerization inhibitor contained in distillates return the L 3 stage to the rectification stage. However, this method is not sufficiently effective in regenerating the polymerization inhibitor, - This is due to the fact that the residue emitted from Ithel still contains not only hydroquinone but also significant if:-operation other inhibitors polimeriza11 TS1I and a dimer or a trimer of acrylic acid and these components at the end kontsov- SELECT syvayuts. All this significantly complicates the process technology. The aim of the invention is to simplify the process technology. The goal is achieved by agreeing with the method of separating acrylic acid obtained by catalytic oxidation of propylene with gas containing oxygen in the vapor phase from the bottom liquid of the distillation column by destructive evaporation at elevated temperature, the evaporation of the bottom liquid was conducted at a pressure of 20100 mm Hg, temperature 120-220 0 to obtain a residue containing 6 wt.% Acrylic acid and: 10.5-47.5 wt.% Dimer acrylic acid, with a total amount of them in the reaction mixture 11.7-50%, followed by extraction residual water at The residue: water 1: ratio (1-10 at. Preferably the extraction residue is carried out at 20-60 ° C and the residue: water ratio 1: (3-6) is mass-based. The invention is applicable to any processes for producing acrylic acid. Processes Acrylic acid production includes the steps of contacting with water in the presence of hydroquinone, which serves as a polymerization inhibitor, a gaseous reaction product containing acrylic acid, which is obtained by catalytic vapor phase oxidation of an olefinic compound of the general formula CH CHCHR, where R is by k More than one member selected from the group consisting of CH and CHO, such as propylene and acrolein, with a gas containing oxygen molecules, such as air, thereby collecting acrylic acid in the form of an aqueous solution, and separating acrylic acid from the aqueous solution . The isolation of acrylic acid usually involves the step of removing water from the aqueous solution by extracting with an extracting solvent such as ethyl acetate, ethyl acrylate, etc., the step of separating the solvent, the step of separating the acetic acid by-product from the system, and the step of purifying acrylic acid. In some cases, the extractive step and the solvent separation step may be skipped, depending on the acrylic acid selection conditions used in the acrylic acid selection stage. In this case, only the stage of acrylic acid distillation (carried out by distillation or azeotropic distillation using the required number of distillation columns) is used for the separation of acrylic acid. The dimer of acrylic acid is obtained even in the collection stage and in the form of an aqueous solution which forms β-acrylic acid by an oxidation reaction, and will be extracted together with acrylic acid in the subsequent extraction, the dimer being fed to the final stage of the distillation column and finally collected in a distillation cube columns. Correspondingly, the cubic liquid of the distillation column contains acrylic acid, acrylic acid dimer, polymerization inhibitor, and other high-boiling substances. The composition of the bottom liquid is highly dependent on the conditions of the respective stages, but in general it represents 20-65% by weight of acrylic acid dimer, 5-15% by weight of polymerization inhibitor, such
    as hydroquinone, and less than 20% by weight of high boiling point substances.
    The bottom liquid is first subjected to evaporation so as to decompose only the dimer of acrylic acid, which is contained in the liquid, into acrylic acid so as to allow it to evaporate together with the acrylic acid, which was originally contained in the bottom liquid, for recovery in distillate, but also overtake and part of the dimer of acrylic acid. Unexpected; This is because dimer serves as a solvent, forming azeotropic mixtures, and makes it possible to simultaneously extract hydroquinone, which is used as a polymerization inhibitor and is concentrated in large quantities. The residue from the step of transformation is then subjected to extraction with water to extract acrylic acid, acrylic acid dimer and hydroquinone, while high-boiling substances, such as polymeric materials, are thrown out of the system as waste oil. In this case, it is necessary that the composition of the residue, which is fed to the extraction stage using water, consists of 1-25% by weight of acrylic acid, 9-19% by weight of acrylic acid dimer (and the total amount of acrylic acid and dimer of acrylic acid is in the region of 1050 wt.%) and accordingly 90-50 wt. other substances, such as high boiling substances and hydroquinone
    If the composition has an extremely high content of components, then high-boiling substances are not separated as an oil layer and are suspended in water, so that the separation and extraction of acrylic acid, its dimer and hydroquinone becomes difficult. In the case when the residue after evaporation is fed to the extraction stage with practically water, it is necessary to control the residue so that it has the indicated composition.
    Acrylic acid, acrylic dimer and hydroquinone, which are collected as a distillate at the evaporation stage, can be sent to the acrylic acid separation stage from the aqueous solution, which results in the separation of hydroquinone
    re-used as a polymerization inhibitor and acrylic acid helps to improve its recovery. In a separation step, the specified distillate can be recycled to KOTOV, can be any of the stages of solvent extraction, solvent separation, acetic acid separation, acetic acid distillation, and the like. Of these, the acetic acid separation step is most preferred.
    The residue after evaporation may, if necessary, be decomposed — to then sent back to the evaporation stage. During circulation, high-boiling substances should be collected in the system, with some of the decomposition product taken out and fed to the aqueous extraction stage. On the other hand, part of the decomposition product may be further evaporated to extract acrylic acid distillate, acrylic acid dimer and hydroquinone, followed by circulation to the acrylic acid separation stage, for example, the acrylic acid purification stage. and for the evaporation step). The remainder of this is further subjected to further installation and the necessary; (MOST decomposition and circulate to an evaporation stage, part of which is fed to the water extraction stage.
    The acrylic acid dimer formed in the system is decomposed into acrylic acid in evaporation and decomposition stages. The acrylic acid thus obtained is evaporated and recovered together with the dimer of acrylic acid and hydroquinone and reused by recycling into the purification system in the form of a solution of acrylic acid dimer with acrylic acid and hydroquinone. Further, the extracted acrylic acid, acrylic acid dimer and hydroquinone are regenerated in the extraction step with water as an extract and circulated as an aqueous solution for reuse in these steps, for example, in an acrylic acid collection step or in a solvent extraction step, preferably in a collection step. Thus, 80-98% of acrylic acid dimer, by-produced during the process of the proposed method.
    can be regenerated in the form of acrylic acid and 70-95% of hydroquinone and collected and reused as a polymerization inhibitor, which provides an increase in the net yield of acrylic acid and significantly reduces the cost of hydroquinone of the expensive polymerization inhibitor.
    Fig. 1 shows a device for carrying out the proposed method for isolating acrylic acid; in fig. 2 - the same, option.
    In the system shown in FIG. 1, propylene or acrolein, or a mixture thereof, supplied via line 1, is catalytically oxidized in the vapor phase by a gas containing molecular oxygen, such as air, supplied through line 2 to a reducer 3. Gaseous oxidation product containing acrylic acid , is fed through line 4 to the absorption column .5, in which it is countercurrently contacted with water in the presence of hydroquinone as a polymerization inhibitor, in order to obtain an aqueous solution. The aqueous solution containing acrylic acid thus obtained is fed through line 6 to an extraction column 7, in which the aqueous solution is subjected to extraction with an organic solvent, such as ethyl acetate, ethyl acrylate, etc., and water is discharged through line 8, while line 9 p column 10 separation of the solvent. The solvent, separated in the 10th column of the separation, is circulated in the water; The SRI 11 into the extraction column 7. Acrylic acid and other components are passed through line 12 to the column 13 of the acetic acid separation, where the acetic acid, which is a by-product of oxidation, is separated off, along the line 14, and the crude acrylic acid is fed through line 15 Acrylic acid distillation column 16 Acrylic acid is distilled from the top of rectification column 16
    And pass through the condensing device 17 to the tank 18. Part of the outgoing acrylic acid is fed back to the distillation column while refluxing, the residue is withdrawn. In the bottom part of the distillation column 16, the acrylic acid is collected, which /
    contains, in addition to the acid itself, concentrated acrylic acid dimer polymerization inhibitors, such as hydroquinone, and other high-boiling substances, such as polymeric materials. This -cubic fluid is fed through a pump 19 to the evaporator 21 of the acrylic acid dimer disintegrator 21 through line 20 and the evaporated substance is condensed in a condensing device 22 and accumulated in tank 23, followed by circulation through line 25 to the stage of separation of acrylic acid, for example Acetic acid separation column 13. Using an acrylic acid extraction pump 24, extracting acrylic acid dimer and hydroquinone. The accumulated liquid can be sent to the solvent extraction column 7, the solvent separation column 10 or the acrylic acid distillation column 16.
    On the other hand, the liquid discharged from the bottom of the column is passed through line 26 and accumulated in decomposition vessel 27, some of which is recycled through pump 28 and through line 29 to evaporator 21 to decompose to evaporate and recover acrylic acid decomposed in vessel 27 for decomposition. The other part of the accumulated liquid falls along line 30 into the extraction column 31. The decomposition evaporator 21 can be of any type, preferably a thin-layer evaporator, equipped with a jacket, it has, therefore, a design that can be heated by a surface heat carrier, such as steam. The evaporator is required to operate under reduced pressure in order to ensure the separation of acrylic acid from acrylic acid dimer, hydroquinone as a polymerization inhibitor and other high-boiling polymeric substances. The conditions of operation of the evaporator are 21 decomposition: heating temperature 120–220 ° C and operating pressure 20–100 mm Hg.
    When polymerization inhibitors, such as amine compounds and organic and inorganic copper compounds, are used in the separation and purification of acrylic acid in combination with hydroquinone, they serve as a decomposition catalyst for the conversion of the dymer of shfilic acid to acrylic acid.
    acid in order to ensure the predominant decomposition of the acrylic acid dimer at the lowest possible heating temperature (120180 o.
    Although in the distillation column the composition of the bottom liquid that is fed through line 20 to the decomposition evaporator 21 may vary widely depending on the operating conditions of the respective stages, it usually contains 20-65% by weight of acrylic acid, 3060 mco% of acrylic acid dimer, 5- 15% by weight of a hydroquinone polymerization inhibitor and less than 20% by weight of other high boiling point substances, most of which are composed of polymeric materials of acrylic acid. This liquid is decomposed and evaporated to a level of 40-80% by weight, condensed in a condensing device 22 and after condensation is distilled into a reservoir 23. The distillate has the composition: 20-99% by weight acrylic acid, 1.60% by weight acrylic dimer acid and 0.1-10 wt.% polymerization inhibitor. The liquid supplied through line 26 to cracking tank 27 has the following composition: 1.2-11.6% by weight of acrylic acid, 10.5-47.5% by weight of acrylic acid dimer, 5-30% by weight of hydroquinone and 85-25 wt.% other high-boiling polymeric substances ..
    Acrylic acid dimer is decomposed in a decomposition vessel 27. The vessel has such a design that provides heating and maintaining the temperature in the range of 120-220 0, preferably 150-200 C, for 1-8 hours, preferably 3-8 hours,
    The decomposition reaction of acrylic acid dimer to acrylic acid has an equilibrium ratio. In practice, other high-boiling substances contain a sample, tetramer, and other acrylic acid oligomers. Thus, the equilibrium ratio is established in a multicomponent system. Although the decomposition rate and equilibrium concentrations are not known, it can be assumed that the decomposition reaction does not occur at temperatures below — in this case dimerization occurs to produce an acrylic acid dimer and at temperatures above 120 ° C — the dimer (tetramer) of acrylic acid decomposes. With this in mind the evaporator 21
    decomposition and decomposition vessel 27 should be at a temperature. 120 C. In the decomposition evaporator 21, the temperature and pressure are controlled within the limits indicated so as to evaporate the acrylic acid and part of the acrylic acid dimer, but not to evaporate the polymer / type products, except for the dimer. Thus, in a controlled evaporator 21, acrylic acid dimer acts as a solvent, forming an azeotropic mixture with hydroquinone during distillation, which allows hydroquinone to be collected as a solution in an acrylic dimer.
    In the decomposition evaporator 21, the acrylic acid is quickly distilled into the external system after the decomposition reaction. Here, the equilibrium shifts to the preferred formation of acrylic acid, which causes the decomposition reaction to proceed smoothly. Thus, it is enough that the residence time in the system is short, about 10 minutes. However, acrylic acid decomposed in decomposition vessel 27 is not released into the external system. Therefore, its residence time here is 1-8 hours. Although the residence time depends on the temperature and composition of the liquid, in conditions of decomposition vessel 27, this requires 3-8 hours. A residence time of more than 10 hours does not provide any improvement in decomposition from established equilibrium, and thus economically unprofitable.
    In the case of supplying a part of the outgoing; LIQUID from the decomposition vessel 27 into the extraction column 31, when the total content of acrylic acid and its dimer in the liquid composition ejected from the decomposition vessel 27 exceeds 50% by weight due to either insufficient decomposition of the acrylic acid dimer in the evaporator 21 decomposition and decomposition vessel 27, or insufficient distillation of acrylic acid or its dimer from the above apparatus, the liquid exhibits such a property as the formation of a homogeneous phase with water in the extraction column, which results in extraction possibilities. On the other hand, when the decomposition of the acrylic acid dimer occurs excessively efficiently and the acrylic acid and its dimer is removed from the system.
    that the total amount of acrylic acid and its dimer in the liquid composition becomes no more. 10 wt.%, The liquid is solidified at normal temperature and extraction becomes impossible. In order to feed the exiting liquid from the decomposition vessel 27 to the extraction column 31, it is necessary to control the total amount of acrylic acid and its dimer in the liquid composition, which should be areas below 50 wt.% (typically 20-45 wt.%) of the liquid composition in question, supplied from the decomposition evaporator 21, and appropriately select the specified operating conditions.
    A solution of acrylic acid, dimer and hydroquinone, which is distilled from the decomposition evaporator 21, is circulated to the solvent separation stage and the acetic acid separation stage and then removed for. reuse as polymerization inhibitor. The liquid of the decomposition vessel 27 discharged from the decomposition evaporator 21 is supplied by a pump 28 and line 30 to the upper part of the extraction column 31. At the same time, water is supplied from the lower part of the extraction column through line 32 for efficiently conducting countercurrent extraction. The extract is recovered through line 33 in the form of an aqueous solution of acrylic acid, its dimer and hydroquinone, and is actually supplied to the acrylic acid collection stage in aqueous form (absorption column 5) and any stages between the extraction stage of acrylic acid and the solvent separation stage for use as a polymerization inhibitor Other high-boiling polymeric substances are discharged to the outside via line 34 and are considered used oil.
    The extraction column 31 can be of any type, it is preferable to use a rotating: disk column, since the extraction residue has a high viscosity and adheres.
    Extraction conditions: temperature, preferably 20-60 s and the ratio of extracting reagents, i.e. liquids discharged from the bottom of the column and water 1: (1-10) (parts), preferably 1: (3-6),
    The recovery of acrylic acid dimer and hydroquinone in the extraction column is 70-95 and 50-90% by weight, respectively. Even if large amounts of water are used (the ratio of extracting reagents is in the range of 1: 6 or higher), the recovery of dimer of acrylic acid or hydroquinone does not increase. But such use is economically disadvantageous, since either hydroquinone is extracted in the form of more dilute solutions. On the other hand, when an extracting ratio of 1: 3 or less is used to reduce water consumption, the recovery of the acrylic acid dimer is sharply reduced, and the recovery of hydroquinone is also reduced. If the ratio is in the range of 1: 1 or less, a homogeneous phase is formed and thus the extraction becomes impossible.
    According to the second embodiment of the device (Fig. 2), the liquid discharged from the first decomposition evaporator 21 is fed via line 26 to the decomposition vessel 27. Part of the liquid is recycled, to the decomposition evaporator 21 via line 35 and to the second evaporator 36. The evaporated substance is liquefied in the condenser 37 ,. accumulated in reservoir 38. and recovered for reuse as a solution of acrylic acid and hydroquinone in an acrylic acid dimer by feeding to the indicated stages. using a pump 39 and line 40. At the same time, the liquid discharged from the bottom of the evaporator 36 accumulates in the vessel 42 decomposition in line 41, with some of the liquid being recycled to the evaporator 36 by means of a pump 43 and line 44. Another part is passed through line 30 to the extraction column 31, Although the polarizer 36 can be of any type, usually an evaporator of the same type is used type, as the first evaporator 21 decomposition. The operating conditions of the second evaporator are the same as the operating conditions of the first evaporator 21 decomposition.
    As is clear from the foregoing, in the steps of the separation and purification of acrylic acid, hydroquinone must be added as an inhibitor. Not looking at completely suppressing the formation of acrylic acid dimer is not possible, by using the decomposition of dinar of acrylic acid decomposition vessels and extractor using evaporators 21 and 36, it is possible to recover added hydroquinone up to 70-95% and extracts of acrylic acid decomposition to 8098 wt.% from the formed acrylic acid dimer. At the same time, acrylic acid contained in the bottom liquid of the distillation column can be extracted up to 90 wt.% Or more, which substantially increases the net yield. If the extraction column is not used, then a solution of hydroquinone in the acrylic acid dimer, non-aqueous solution, containing acrylic acid dimer and hydroquinone. In this case, however, the recovery of the acrylic acid dimer or hydroquinone will be significantly lower. An important aspect of the invention is that acrylic acid and its dimer decompose and evaporate as much as this, and at the same time, treatment of hydroquinone for the same period without evaporation of high boiling point polymeric substances is performed either by increasing the heating temperature or decreasing working pressure in the evaporation stage, with decomposition. The total amount of acrylic acid and its dimer in the liquid composition, discharged from the bottom of the evaporator 21 or 36, will eventually be reduced to 10% by weight. Such a liquid cannot be subjected to extraction and is appropriately discarded as waste oil. Example 1. An acrylic acid apparatus is used which has an annual capacity of 25,000 tons, adapted to perform a catalytic vapor phase oxidation process using propylene as the starting material and hydroquinone as a polymerization inhibitor. The apparatus is equipped with a device of the thin film evaporator type for evaporation with decomposition of acrylic acid dimer, having a heat-conducting surface of 3 m and containing a decomposition vessel with a volume of 1 m and a subsequent 20-stage extraction column with rotating discs with an internal diameter of 400 mm. A gas mixture containing 5.0% by volume of propylene, 10% by volume of oxygen, 10% by volume of water vapor, 73.9% by volume of nitrogen, 0.75% by volume of carbon dioxide and 0.35% by volume of oxide carbon at 320t for 2.7. s is passed into the reactor, filled with 1 atalizatr of the following composition :. .bi), oi, to obtain a reaction mixture of the following composition: 4.3 vol.% acrolein, 0.3 vol. 7, acrylic acid, 0.2 vol.% propylene, 4.5 vol.% oxygen, 15 vol.% water vapor, 73.5% by volume of nitrogen, 1.09% by volume of carbon dioxide and 0.51% by volume of carbon monoxide. Then, the reaction gas mixture at a flow rate of 3000 hours is passed into a reactor filled with a catalyst of the following composition: Mo Vg Sr W 4 zi Conversion of the starting acrolein is 99.5%, selectivity for acrylic acid is 97.4% and yield of acrylic acid per pass 96, 9%. The evaporation apparatus with the arrangement is arranged to be heated with the help of steam with a temperature and the pressure in the system was. lowered to 0.066 atm (50 mm Hg). The decomposition tank heats up. Under these operating conditions, the bottoms liquid from the distillation column of the acrylic acid manufacturing apparatus is fed to the evaporator apparatus for decomposition. It was found that the amount of evaporating liquid reaches 76% by weight. 1 Raw materials, distillate, liquid discharged from the bottom of the evaporation apparatus with decomposition, and the liquid leaving the decomposition vessel have the compositions shown in Table 2. 1. The decomposition rate of acrylic acid dimer into acrylic acid and the recovery of hydroquinone in a decomposition evaporator and decomposition vessel is 48.9% (97.8% based on the dimer obtained) and 36.9%, respectively., After decomposition and evaporation, the liquid discharged from the apparatus is fed to the upper part of the extraction columns 1. The water supply is five times higher than the liquid supply from the bottom of the extraction column at 1511 normal temperature and thereby countercurrently extracts dimer of acrylic acid and hydroquinone-In ltate aqueous solution containing acrylic acid dimer and hydroquinone in amounts of 5 and 2 wt.%, respectively, is recovered from the top of the extraction column. The recovery is 90% for acrylic acid dimer and 80% for hydroquinone. About 50% of the oily residue, based on the feed liquid, is discharged from the bottom of the extraction column and discarded as waste oil. The total recovery rates for the acrylic acid dimer and hydroquinone are 94.9% by weight and 87.4% by weight, respectively. Acrylic acid and hydroquinone solution in acrylic acid dimer, extracted from the apparatus for evaporation with decomposition, are fed to the solvent separation stage and the acetic acid separation stage of the acrylic acid production unit. An aqueous solution of acrylic acid dimer and hydroquinone-extracted from extraction columns is passed through an acrylic acid collection step and an acrylic acid extraction step to a solvent separation step for reuse as a polymerization inhibitor. 6 months or more after the start of work, the apparatus for the production of acrylic acid works without any difficulties, such as. Concentration or deposition of high-boiling polymeric substances in the above stages; At the same time, the cost of hydroquinone is reduced by 1/5 compared with the processes that do not use the proposed method of regeneration of the pure 5th output of acrylic acid by 3%. 1 are given in table. 1. Table 1
    Example 2. The same apparatus and operating conditions are used as in Example 1, except that 45 extraction is carried out under such extraction conditions (relative extraction, reagents), when water is used in an amount twice the amount of feed liquids. 50 As a result, the degree of extraction of acrylic acid dimer and hydroquinone c. the extraction column is 60.1 and 70.3 May. 7, respectively.
    PRI me R 3. Use the same 55. The apparatus and conditions as in Example 1, except that hydroxion and copper diethyldithiocarbamate (0.1 wt.% based on copper in the liquid supplied by the kz evaporator with decomposition of the dimer) are used as polymerization inhibitor, the effect of decomposition and extraction, Similar to Example 1, obtained at decomposition temperature by the catalytic action of a copper compound.
    Example 4. —When using the same apparatus and conditions as in Example 1, except that the evaporation apparatus with decomposition of the acrylic acid dimer operates under heating conditions up to and a pressure of 20 mm Hg, overflow.
    85% of the feed fluid is chased. The new part, as well as the liquid, the output of the indicators of the liquid distilling from the decomposition vessel, and also the liquid discharged from the cubic table. 2 ,. 36.1 Discharge liquid 62.9 Distil t Liquid discharged from the bottom of the liquid Discharge from the decomposition vessel
    In the evaporation decomposition apparatus, the recovery due to the decomposition of the acrylic acid dimer is 36.6% (97%) based on the system capacity and the recovery of hydroquinone is 49.2%. The total recovery rates for acrylic acid dimer and hydroquinone are 84.1 and 92.4 wt%, respectively.
    Example 4. (comparative by a known method).
    When the same apparatus and conditions as in Example 1 are used, except that the bottom liquid from the distillation column of the acrylic acid production apparatus is directly fed into the extraction column without passing through the decomposition evaporation apparatus, a homogeneous phase is formed. Thus, the extraction is not possible. In this case, it is not possible to regenerate acrylic acid dimer and hydroquinone.
    Example 5. (comparative by a known method).
    When using the same apparatus and conditions as in Example 1, except that the extraction was carried out under such extraction conditions (ratio of extracting reagents), but using the amount of water 0.6 times less than the amount of feed liquid, then in the column a homogeneous phase is formed that makes
    table 2
    extraction is impossible. In this extraction process, it is not possible to extract either acrylic acid dimer or hydroquinone ..
    Example 6. An apparatus for carrying out the process is supplied with two series-connected apparatus for evaporation with decomposition of an acrylic acid dimer of the same type as used in Example 1. It is combined with a 20-stage extraction column with rotating discs and an inner diameter of 400 mm (FIG. 2).
    Both devices of evaporation with decomposition are arranged in such a way that the heater works with steam with a temperature of 180 ° C, the pressure in the 1st stage of the system is up to 300 mm, and in the second stage of the system up to 80 mm Hg. Each of the decomposition vessels is heated to 180s Under these conditions, the bottom liquid from the distillation column of the apparatus for the production of acrylic acid, as shown in Example 1, is fed to the first stage of the evaporation apparatus with decomposition. The amount of evaporating liquid reaches 55.0 wt.% In the first stage and 63.0 in the one-sided stage.
    Feed liquids, distillates and liquids discharged from the lower parts of the evaporation apparatuses with decomposition, as well as liquids leaving the vessels, decomposition, have the compositions 48, 486, 2 presented in table. 3, Total decomposition rate of dimer. acrylic acid to acrylic acid and the extraction of hydroquinone in these devices, the evaporation with decomposition in decomposition vessels amounts to wt.% (96 may.% based on the dimer produced) and 53.8 wt.%, respectively. After decomposition and evaporation, the liquid discharged from the decomposition vessel of the second stage of the system is fed to the upper part of the extraction column: HUj, while water in quantities five times higher than the feed liquid is supplied from the lower part of the extraction column at normal temperature 1 the same dimer acrylic acid and hydroquinone are extracted countercurrently. As a result, an aqueous solution containing acrylic dimer and hydroquinone in an amount of 5 and 2 wt.%, Respectively, is removed from the upper part of the extraction column. Extraction is 75 wt. 1 for dimer.
    Feed liquids of the first stage of the second stage
    Distil you.
    first stage second stage
    Donna liquid of the first stage of the second stage
    % 1 dc output decomposition vessel
    first stage second stage 11
    6.5
    9.5 14.0 25.7
    0.5 7.9
    14.0
    25.3 18.3 55.5
    14.0
    25.7 18.3 56.1 2820 acrylic acid - and 80 wt.% For hydroquinone. About 50% of the oily residue. In the calculation; the feed liquid is discharged from the bottom of the extraction column and. thrown away like waste oils. The total recovery rates for acrylic acid dimer and hydroquinone are 87.3 and 91.7%, respectively. Acrylic acid and hydroquinone solution in acrylic acid dimer, regenerated from the apparatus, decomposed with decomposition, are fed to the solvent separation stage and the acetic acid separation unit of the acrylic acid production apparatus, and the aqueous solution of acrylic acid dimer and hydroquinone regenerated from the extraction column is passed through through an acrylic acid collecting step and an acrylic acid extraction step and a solvent separation step for reuse as a polymerization inhibitor. Table 3
    21
    Example 7. The same apparatus and conditions were used as in Example 6, except that the second stage of the evaporation apparatus with decomposition of the dimer of acrylic acid was operated under conditions of heating to temperature and pressure.
    Feed liquids of the first stage of the second stage
    Distil you.
    first stage second stage
    Donna liquid, first stage, second stage
    Liquid - exit u out of the vessel decomposed
    first stage second stage
    The liquid discharged from the decomposition vessel of the second stage hardens at normal temperature, and neither the acrylic acid dimer nor hydroquinone can be recovered from the extraction column in the extraction column with the decomposition of the extraction of acrylic acid and hydroquinone dimer and decomposition.
    116952822
    100 mm Hg 85% of the feed fluid is distilled. The feed liquid, distillates, liquid discharged from the bottom part, and the liquid leaving the decomposition vessel have the compositions shown in Table 4.
    Table 4.
    6.5
    9.5 14.0
    25.7
    0.5
    0.5 6.3 9.1
    14.0
    25.3 22.9 69.9
    14.0
    25.7 67.6 22.9
    set at 54.1
    and 70.8% respectively,
    PRI me R s 8-13. The same equipment was used with the creation of the conditions described in Example 1, except that the extraction operation carried out under extraction conditions the proportion of the extraction agent and the temperature indicated in the table, 5,
    Example 14. By analogy with the same embodiment of the method as described in Example 6, the withdrawn VAT residue resulting from the distillation of 60.1% of the initial liquid of the 1st stage (before feeding into the decomposition vessel) is subjected to direct extraction water treatment at a proportion of extraction reagent 5 and a temperature of 20 ° C. The results are summarized in table. 6
    Table 6
    The content of the component, wt.% In the composition
    Acrylic acid
    Acrylic dimer
    acids
    Hydroquinone
    Other components
    Extraction ratio,%
    acrylic acid dimer
    hydroquinone
    Example 15. By the same variant, Table i
    Sob that described in example 7, abstracted VAT residue, - the resulting distillation of 82% of the original
    liquids of the 2nd stage (before being fed into the decomposition vessel), are subjected to extraction treatment directly with water at a ratio of extraction reagent 5 and temperature
    . Half-down results are summarized
    in tab. 7
    Table 7
    The content of the component, wt.%, In the composition
    1.5
    th
    10.0 22.0
    66.5
    Extraction ratio,%
    dimer acry72 lovoy acid
    51
    1IDROHINON
    Example 16. Using the same equipment as in example 1,
    and with the creation of the same conditions, except that in this case the composition of the initial liquid is changed, the discharged VAT residue obtained by distilling off 61% of the liquid (before serving
    Composition of the original
    A9 fluid
    The composition of the exhaust
    21.2 liquids
    Extraction ratio
    Example 17. The equipment is operated under the conditions of example 1 with the exception that destructive evaporation is carried out under conditions of nag, roaring up to 120 ° C at a pressure of 20 mm Hg. . 71.0% of the initial liquid is distilled off. In tab. 9 shows the data on - initial., Liquid, distillate, liquid otvodi-f
    Liquid discharged from the cube of the column
    Fluid removal from the apparatus for destruction
    Example 18 The conditions and conditions of the apparatus of example 1 are operated with the exception that destructive evaporation is carried out under heating conditions at a pressure of 100 mmHg, st. 80.0% of the initial liquid is distilled off. Data on the original fluid, distillate that.
    into decomposition vessel), is subjected to direct extraction with water at a proportion of extraction reactant 5 and a temperature of 20 ° C. The results are summarized in table 8,
    Table 8
    6.5
    35.0
    9.3
    36.6
    27.1 15.1
    90
    my from the cube, and the fluid that is removed from the apparatus for destruction,
    In a destructive evaporation apparatus, it was found that the destructive isolation of acrylic acid dimer is 40.7%, and the release of hydroquinone is 26.2%,
    Table 9
    42,8
    36.1
    16.6
    38.7
    16.6
    36.1
    liquid discharged from the cube, and the liquid discharged from the device for dest. The instructions are given in table. 10,
    In the apparatus for destructive decomposition, the destructive separation of the dimer of acrylic acid is 50.3% and the release of hyproquinone is 38.0%,
    Liquid discharged from the cube of the column
    The liquid discharged from the apparatus for the destruction of Example 19. The apparatus and conditions of Example 1 are used with the exception that they operate at a pressure of 50 mm Hg. without the use of an apparatus for destruction. I73.0% of the initial liquid is distilled off. Data on the initial liquid, distillate and liquid. Example 20. Apparatus and conditions of Example 6 with the exception that destructive reaming is carried out at a pressure of 20 mm Hg in the second stage. At the 2nd stage, 82% of the initial liquid is distilled off.
    Table 10
    46.5
    20.0
    32.3
    46.5
    20.0
    23.4
    The results are shown in Table. 12.
    In the apparatus for destructive evaporation, it was found that the destructive allocation of the acrylic acid dimer is 51.7%, and the release of hydroquinone is 58.5%. bones removed from the cube of the column are given in table. 11. In the apparatus for destructive decomposition, it was found that the destructive distribution of the acrylic acid dimer is 48.4%, and the distribution. hydrolnone - 31.7%. T a b l and c in 11
    Fluids discharged from the cube of the column
    1 stage 2 stage
    LIs liquid discharged from the apparatus for destroits "and
    1-stage 2-stage Example 21. In the preceding Examples 17-19, the extraction was carried out under the same conditions as in Example 1. The results given in Table 1 are obtained. 13 .. T..blice 13
    25.3 66.1
    25.7
    14.0 65.5 21.5 Prolong Table 13 Example 22. In the previous example 20, the extraction was carried out under the conditions of Example 6. The results given in Table 2 are obtained. 13. The advantage of the proposed method, which significantly simplifies the process technology, is the use of acrylic acid dimer, both as a solvent and as an extractant for the recovery of hydroquinone.
    权利要求:
    Claims (2)
    [1]
    1. METHOD FOR ISOLATING ACRYLIC ACID, obtained by catalytic oxidation of propylene by a gas containing oxygen, in the vapor phase from the bottom liquid of a distillation column by destructive evaporation at elevated temperature, characterized in that, in order to simplify the process technology, the evaporation of bottom liquid is carried out at a pressure of 20- 100 mmHg at 120-220 ° C to obtain a residue containing 1.2-11.6 wt.% acrylic acid and May 10.5-47.5.% acrylic acid dimer, with a total of 11 in the reaction mixture, 50%, followed by extraction of the residue with water at a mass ratio of residue and water 1: (1-10) at 5-90 ° C.
    [2]
    2. The method according to p. ^ Characterized in that the extraction of the residue is carried out at 20-60 ° C with a mass ratio of the residue and water 1: (3-6).
    SU <„, Π69528
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    同族专利:
    公开号 | 公开日
    JPS5498718A|1979-08-03|
    JPS6135977B2|1986-08-15|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US7786323B2|2003-11-28|2010-08-31|Mitsubishi Chemical Corporation|Method for collecting acrolein or acrylic acid and collecting device for the same|
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    US10703702B2|2015-07-31|2020-07-07|Novomer, Inc.|Production system/production process for acrylic acid and precursors thereof|JPS6059889B2|1977-09-28|1985-12-27|Nippon Shokubai Kagaku Kogyo Kk|JP4542214B2|1999-08-20|2010-09-08|株式会社日本触媒|Acrylic acid purification method|
    WO2003043968A1|2001-11-20|2003-05-30|Mitsubishi Chemical Corporation|Process for producing acrylic acid compounds|
    JP2005179352A|2003-11-28|2005-07-07|Mitsubishi Chemicals Corp|Method of purifying acrylic acid|
    DE102004008575A1|2004-02-19|2005-09-08|Stockhausen Gmbh|Cleavage of oligomericacrylic acid in the liquid phase under pressure|
    WO2009133813A1|2008-04-27|2009-11-05|株式会社日本触媒|Process for producing acrylic acid, and process for producing hydrophilic resin and process for producing water absorptive resin using the process|
    WO2016125631A1|2015-02-05|2016-08-11|株式会社日本触媒|Method for producing acrylic acid|
    KR20190037944A|2017-09-29|2019-04-08|삼성전자주식회사|Bubble generator and washing machine having the same|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    JP53003753A|JPS6135977B2|1978-01-19|1978-01-19|
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