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    • 专利摘要:
    The invention relates to a method for recovering polymeric (meth) acrylic acid from a gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of a precursor of the (meth) acrylic acid, characterized in that it is carried out in an installation comprising at least two, preferably two, distillation columns in the absence of an organic solvent and in the presence of at least one treatment agent chemical. The (meth) acrylic acid obtained according to the invention meets high quality criteria allowing its use in the manufacture of acrylic polymers, particularly for the field of super absorbents. This grade is also known as glacial acrylic acid AAg.
    公开号:FR3041958A1
    申请号:FR1559493
    申请日:2015-10-06
    公开日:2017-04-07
    发明作者:Sandeep Jain；Michel Fauconet
    申请人:Arkema France SA；
    IPC主号:
    专利说明:

    Dans ce tableau, il apparaît que le rapport de concentration massique furfural /acroléine est bien inférieur à 3 dans le flux 3, et la qualité d’acide acrylique purifié obtenue en soutirage latéral de la colonne 17 (flux 5) n’est pas de qualité suffisante pour être utilisée dans une application requérant une qualité d’acide acrylique de grade polymère. En particulier, les concentrations de furfural et benzaldéhyde et acide / anhydride maléique sont trop importantes pour fabriquer des polymères de forte masse moléculaire répondant aux souhaits des applicateurs.
    Exemple 2 (référence)
    Un mélange synthétique représentatif du milieu obtenu en pied de colonne de déshydratation d’un procédé de purification d’acide acrylique n’utilisant pas de solvant organique externe est préparé. Ce flux synthétique a la composition suivante : Acide acrylique (85,20%), acide acétique (10%), eau (4,4%), acroléine (0,03%), furfural (0,011%), benzaldéhyde (0,015%), anhydride maléique (0,2%), phénothiazine (0,1%), hydroquinone (0,05%). 250g de ce mélange sont introduits dans un ballon en verre et le mélange est distillé dans un évaporateur rotatif à température de 90°C sous pression de 30 mbar, de façon à recueillir environ 80% de fraction distillée.
    Après évaporation, on recueille 201g de distillât incolore et limpide, titrant 0,01% furfural, 0,01% benzaldéhyde, 0,03% acroléine, 0,15% d’acide / anhydride maléique.
    Les résultats de cet essai reflètent la partition des impuretés dans les conditions de distillation flash, sans plateau de séparation. Il sert de référence aux essais suivants réalisés en présence d’agents chimiques de traitement des aldéhydes.
    Exemple 3 (selon l’invention)
    Le même traitement que l’essai 2 est répété à partir de 200g du même mélange synthétique, mais en ajoutant cette fois 0,35g d’hydrate d’hydrazine. En outre, le mélange est d’abord porté à 40°C pendant 60 minutes sous pression atmosphérique, puis distillé dans l’évaporateur rotatif à température de 90°C sous pression de 30 mbar.
    On récupère 154g (77%) de distillât incolore et limpide, titrant < lppm furfural, < lppm benzaldéhyde, < lppm acroléine, < lppm d’acide / anhydride maléique.
    Le résidu recueilli non distillé recueilli après évaporation est limpide et sans dépôt de solide.
    Exemple 4 (selon l’invention)
    Le même traitement que l’essai 3 est répété, à partir de 200g de mélange synthétique décrit dans l’essai 2, mais en ajoutant cette fois 0,31g de bicarbonate d’aminoguanidine.
    Après évaporation, on recueille 152g (76%) de distillât incolore et limpide, titrant < lppm furfural, < lppm benzaldéhyde, < lppm acroléine, 48ppm d’acide / anhydride maléique.
    Le résidu recueilli non distillé recueilli après évaporation est limpide et sans dépôt de solide.
    Exemple 5 (selon l’invention)
    Le même traitement que l’essai 3 est répété, à partir de 200g de mélange synthétique décrit dans l’essai 2, mais en ajoutant cette fois 0,47g de métaphénylènediamine.
    Après évaporation, on recueille 157g (78%) de distillât incolore et limpide, titrant < lppm furfural, 3ppm benzaldéhyde, < lppm acroléine, 7ppm d’acide / anhydride maléique.
    Le résidu recueilli non distillé recueilli après évaporation est limpide et sans dépôt de solide.
    Les exemples 3, 4 et 5 montrent qu’il est possible d’obtenir, à partir d’un flux représentatif de fond de colonne de déshydratation obtenu selon un procédé de récupération / purification sans addition de solvant, une qualité d’acide acrylique de grade polymère, sans étape de distillation supplémentaire, grâce à un traitement par un agent chimique.
    IMPROVED PROCESS FOR THE PRODUCTION OF POLYMERIC (METH) ACRYLIC ACID
    TECHNICAL AREA
    The present invention relates to the production of polymeric grade (meth) acrylic acid. The term "polymer grade" indicates that acrylic acid meets high quality criteria allowing its use in the manufacture of acrylic polymers, particularly for the field of super absorbents. This grade is also known as glacial acrylic acid AAg. The invention more particularly relates to a process for the recovery / purification of (meth) acrylic acid of polymer grade from a crude reaction mixture comprising (meth) acrylic acid, said process not using a solvent organic or crystallization treatment, and including treatment with a chemical agent. The invention also relates to an installation adapted for implementing said recovery / purification process, as well as to a process for producing (meth) acrylic acid of polymer grade.
    TECHNICAL BACKGROUND AND TECHNICAL PROBLEM Acrylic acid is essentially intended for the use by industrialists of polymerization processes (or copolymerization in the presence of other polymerizable monomers), either acrylic acid as such, or its derivatives in the form of salts (for example sodium acrylate), esters (alkyl acrylates) or amides (acrylamide). These processes are conducted in various forms, in bulk, in solution, in suspension or in emulsion.
    The polymerization and / or copolymerization processes involving acrylic acid can be very sensitive to the presence in the feed of certain impurities, such as unsaturated compounds or aldehydes, which can sometimes prevent the expected use value from being obtained. for example by limiting the conversion of monomer to polymer, limiting the chain length of the polymer, causing crosslinking reactions or modifying the reactivity of the reaction.
    Some of these impurities, such as saturated non-polymerizable compounds, can also be particularly troublesome in the final application of the polymer, by modifying the properties of the polymer, by conferring toxic or corrosive properties on the polymer, or by increasing the organic polluting discharges. during the manufacturing steps of the polymer and / or the finished product.
    As a result, users of acrylic acid or acrylic acid derivatives are demanding in terms of quality specifications of acrylic acid. It must meet strict thresholds for impurities.
    In addition, these users implement recipes for the production of their polymers that are adapted to a "standard" quality of acrylic acid or its derivatives. A modification of the recipes used by these users, in order to adapt them to a different quality of acrylic acid, would have significant disadvantages for these user societies.
    The quality (or the purity) of the acrylic acid, that is to say the content of different impurities, playing a big role in the polymerization processes, the manufacturers manufacturing this acrylic acid have been led to stake a whole a series of purification steps to obtain this "standard" acrylic acid usually referred to as polymer grade acrylic acid or glacial acrylic acid (AAg). This AAg does not meet officially recognized specifications and has a universal character, but means for each manufacturer the level of purity to reach in order to successfully conduct its polymerization in acid form or in the form of a derivative and obtain polymers compatible with their end uses.
    The acrylic acid recovery / purification methods described in the prior art are very complex when it comes to producing polymer grade acrylic acid and have many disadvantages.
    Indeed, the processes for synthesizing acrylic acid always lead to a gaseous reaction medium consisting of a complex mixture of impurities, generally classified according to their ability to be condensed into a liquid mixture or absorbed in a liquid mixture, or classified depending on their boiling point relative to that of acrylic acid (light compounds, or heavy compounds).
    It follows that the purification processes usually use a set of operations to separate and recover the acrylic acid contained in this gaseous effluent.
    Some of these operations use one or more organic solvents as absorption agents (gas-liquid exchanges) and / or as extraction agents in a liquid medium (liquid-liquid exchanges), and / or as separation agents by azeotropic distillation. These processes, which include in particular, in addition to the steps of separating the desired product, solvent recovery and purification treatment steps, necessarily involve a large number of distillation columns leading to a technical acrylic acid, wherein the The impurity content has been greatly reduced, but does not meet the specifications of a glacial acrylic acid necessary to obtain, for example, high molecular weight polymers. Other methods, such as, for example, that described in patent EP 2 066 613 B1, make it possible to simplify the recovery and purification of acrylic acid, by significantly reducing the number of unit operations required for obtaining the purified product. These processes are characterized by the fact that they do not involve any addition of organic solvent external to the process, and that they use a limited number of distillation columns, in particular less than 3 columns. These simplified processes make it possible to obtain a technical grade acrylic acid high purity, which can reach or exceed 99%, but still not sufficient for the most demanding applications of acrylic acid requiring polymers of high molecular masses, for which a quality of glacial acrylic acid (or polymer grade) is required.
    To reach a quality of glacial acrylic acid, it is necessary to remove up to a very high level (at most a few ppm), certain impurities still present in the technical acrylic acid obtained according to the aforementioned methods.
    These include certain aldehydes, such as furfuraldehyde, benzaldehyde and acrolein, or other impurities such as protoanemonin, a heavy compound generated during the synthesis of acrylic acid, or polymerization inhibitors. non-phenolics such as phenothiazine may have been introduced during the synthesis of (meth) acrylic acid.
    These impurities can be removed by an additional treatment step by fractional crystallization, as described for example in US 6,448,439 or EP 2,066,613 B1.
    Fractional crystallization is a well-known separation technique. It can be implemented in various forms, dynamic crystallization, static crystallization or suspension crystallization (US 5,504,247, US 5,831,124, US 6,482,981).
    However, the additional purification by fractional crystallization is costly in investment and energy required for successive cooling and heating phases. Therefore, additional purification processes by distillation are commonly used for the removal of impurities from technical acrylic acid. However, this elimination up to extremely low levels of a few ppm can not be obtained economically by simple distillation, partly because of their high concentrations relative to the threshold of their sensitivity to the polymerization reactivity and secondly the volatility of some of these compounds, too close to that of acrylic acid.
    To do this, manufacturers generally use processes combining a purification by distillation and a chemical treatment with a reagent which forms with the aldehydes heavy reaction products that are more easily separable from acrylic acid by distillation.
    Among the reagents that can be used, amines, compounds of the family of hydrazines or aminoguanidine, used as such or in the form of their salts, or in admixture (US Pat.
    The chemical treatments which are described in the prior art all have the drawback of generating water during the reaction of the aldehydes with the reagent. The presence of water in acrylic acid can also be harmful for the manufacture of certain polymers.
    For this reason, it has been proposed in JP 49-95,920 to perform this chemical treatment during a distillation step to remove the water and the light compounds at the head, before a distillation step of the acrylic acid intended for separate the heavy compounds.
    These various techniques combining purification of technical grade acrylic acid by distillation and chemical treatment are described in particular for the purification of technical acrylic acid obtained by conventional processes involving at least one external organic solvent. They have the disadvantage of requiring a complementary purification section, with at least one additional distillation column equipped with its annexes (reboiler, condenser, pumps, etc.), which has a negative impact on the cost of the industrial unit and also on energy consumption.
    In addition, the chemical treatment is generally accompanied by the formation of solids which accumulate gradually and require frequent cleaning of the equipment, negatively impacting the productivity of the installation.
    According to the acrylic acid purification process described in the Nippon Shokubai patent EP 1110940, it is necessary to adjust between 3 and 100 the concentration ratio of furfural to acrolein by weight present in the acrylic acid to be treated. , so as to improve the effectiveness of the aldehyde removal treatment with a chemical agent of the hydrazine type. Under these conditions, the amount of chemical agent to be introduced is reduced and the formation of polymers is limited.
    There is therefore still a need for a process for recovering / purifying acrylic acid leading to a quality of acrylic acid of polymer (or glacial) grade which is simplified, fast and easy to implement (having the least amount of 'possible steps), not requiring the intervention of organic solvent and / or azeotropic, or expensive energy technology or pollutant and which further does not generate formation of polymer fouling equipment.
    The inventors have now discovered that this need could be satisfied by implementing a purification section of a gaseous reaction mixture of acrylic acid without the addition of an external organic solvent, and without crystallization treatment, in particular in an installation comprising a column dehydration, and a finishing column (or purification column) fed with a portion of the foot flow of the dehydration column, and including a chemical agent treatment step, preferably performed at the inside the aforementioned purification section, or alternatively in a complementary purification section by distillation, and to lead directly to a quality of glacial acrylic acid.
    It has also appeared to the inventors that this invention could be applied to acrylic acid and methacrylic acid produced from different sources, as well as to these acids derived from renewable raw materials, which are likely to pose the same problems of purification.
    SUMMARY OF THE INVENTION
    The present invention relates to a process for recovering polymeric (meth) acrylic acid from a gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of an acid precursor (meth) acrylic, characterized in that it is carried out in an installation comprising at least two, preferably two, distillation columns in the absence of organic solvent and in the presence of at least one chemical treatment agent.
    More particularly, the process for recovering (meth) acrylic acid of the polymer grade according to the invention comprises at least the following steps: i) subjecting the gaseous reaction mixture to dehydration without using an azeotropic solvent in a first column of distillation known as a dehydration column, leading to a head flow of which at least a portion is condensed and returned to the dehydration column in the form of reflux, and to a foot flow; ii) at least partially submitting the dehydration column foot stream to a distillation in a second column called finishing column, leading to a head flow, and to a foot stream containing heavy compounds; iii) a flow of purified (meth) acrylic acid is recovered by lateral withdrawal from the finishing column.
    According to certain particular embodiments, the chemical treatment agent is introduced into the finishing column or at the bottom of the dehydration column, and the flow of purified (meth) acrylic acid withdrawn in step iii) is a flow. gaseous (meth) acrylic acid of polymer grade.
    According to other particular embodiments, the flow of purified (meth) acrylic acid withdrawn in step iii) is subjected to an additional treatment by distillation using one or two distillation column (s) and the introduction of the chemical treatment agent is carried out during said treatment, thus leading to a flow of (meth) acrylic acid of polymer grade.
    In the present invention, the term "(meth) acrylic" means "acrylic" or "methacrylic".
    The term "azeotropic solvent" denotes any organic solvent having the property of forming an azeotropic mixture with water.
    The term "non-condensable" or "non-condensable" refers to compounds whose boiling point is below the temperature of 20 ° C at atmospheric pressure.
    The term "light" qualifying by-product compounds refers to compounds whose boiling point is lower than that of (meth) acrylic acid under the working pressure in question, and by analogy, the term "heavy" refers to compounds whose boiling point is greater than that of (meth) acrylic acid.
    The process according to the invention may furthermore comprise other preliminary, intermediate or subsequent stages provided that they do not adversely affect the obtaining of (meth) acrylic acid of polymer grade.
    According to certain particular embodiments, the invention also has one or, preferably, several of the advantageous characteristics listed below: the chemical treatment agent is introduced into the finishing column via the feed stream said column; the chemical treatment agent is introduced directly into the finishing column at a section situated between the feed level of said column and the level of the side extraction tray of the purified (meth) acrylic acid; the chemical treatment agent is introduced at the bottom of the dehydration column, preferably into the liquid stream brought into contact with the reaction gas stream for the purpose of cooling it; the chemical treatment agent is introduced during an additional treatment by distillation of the stream withdrawn laterally from the finishing column. the chemical treatment agent is introduced into the installation via a mixing device comprising at least one capacity ensuring the intimate mixing of the chemical agent with the flow to be treated and providing the most appropriate conditions for effective treatment. In this mode of operation, the capacity ensures the mixing of the reagents with the flow of (meth) acrylic acid containing the aldehyde impurities to be removed, and the chemical treatment can be carried out under conditions of temperature and residence time allowing efficiency optimal; the finishing column is a conventional distillation column; the finishing column is a separating wall column fed on one side of the wall by the dehydration column foot flow and the lateral withdrawal of the stream of purified (meth) acrylic acid is carried out in the gaseous or liquid phase in the section on the other side of the divider wall. The flow of top of the finishing column is returned partly to the top of this column, in order to ensure a liquid reflux in the section delimited by the separating wall comprising the lateral withdrawal.
    According to one embodiment of the invention, the precursor of (meth) acrylic acid is acrolein.
    According to one embodiment of the invention, acrolein is obtained by oxidation of propylene or by oxyhydrogenation of propane.
    According to one embodiment of the invention, the precursor of (meth) acrylic acid is methacrolein.
    According to one embodiment of the invention, methacrolein is obtained by oxidation of isobutylene and / or tert-butanol.
    According to one embodiment of the invention, methacrolein is obtained from butane and / or isobutane oxidation hydrogenation.
    According to one embodiment of the invention, the gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of a precursor of (meth) acrylic acid comprises carbon of renewable origin.
    According to one embodiment of the invention, the (meth) acrylic acid precursor is derived from glycerol, 3-hydroxypropionic acid or 2-hydroxypropionic acid (lactic acid).
    According to a preferred embodiment of the invention, the gaseous reaction mixture comprises acrylic acid derived from propylene obtained by a two-stage oxidation process.
    The recovery process according to the invention produces a flow of (meth) acrylic acid of polymer grade, corresponding to a satisfactory quality to produce polymers of high molecular weight, used for example as superabsorbents. The process according to the invention does not require the use of an external organic solvent to remove the water contained in the gaseous reaction mixture comprising (meth) acrylic acid. The process according to the invention does not implement crystallization treatment. In a preferred mode of operation, the process according to the invention requires from the reaction gas mixture only a purification section based on two distillation columns including a treatment step using a chemical agent, carried out within said section.
    The present invention also relates to an installation for recovering (meth) acrylic acid of polymer grade, adapted to implement the method according to the invention. The plant according to the invention comprises at least: a) a dehydration column; b) a finish column fluidly connected to the bottom of said dewatering column; c) optionally at least one distillation column fluidly connected laterally to said finishing column; d) a mixing device ensuring the introduction, mixing and optimal reaction conditions of the chemical treatment agent in the dehydration column foot feed to the finishing column, optionally comprising an intermediate capacity.
    By "fluidic connection" or "fluidically connected", it is meant that there is connection by a pipe system capable of transporting a flow of material. This connection system can include valves, taps, heat exchangers or compressors.
    "Intermediate capacity" denotes an enclosure capable of containing a certain volume of liquid, supplied with a liquid stream passing intermediately in this capacity before being sent to the next stage of the process.
    "Mixing device" means a set of equipment in series ensuring the most effective dispersion of the chemical treatment agent in the flow to be treated and the conditions of residence time and temperature to obtain optimum efficiency. of the reaction.
    Another object of the invention is a process for producing (meth) acrylic acid of polymer grade comprising at least the following steps: A) is subjected to a gas phase oxidation at least one (meth) acrylic acid precursor to form a gaseous reaction mixture comprising (meth) acrylic acid; B) the gaseous reaction mixture is cooled; C) the cooled gaseous reaction mixture is subjected to the process of recovering the polymeric (meth) acrylic acid as defined above.
    The present invention makes it possible to produce polymeric grade (meth) acrylic acid in an overall process which does not involve the use of an organic solvent, thereby reducing the energy recovery costs and rejects compared to a conventional organic solvent process. The process according to the invention uses a simpler technology than fractional crystallization in batch mode or continuous crystallization in suspension.
    In its preferred mode of operation, that is to say without additional distillation column compared to the method of the prior art producing a grade of (meth) acrylic acid technical grade, the present invention also allows to reduce further investment and energy costs of purification to produce polymeric or glacial grade (meth) acrylic acid. Moreover, the formation of solid polymers fouling the equipment being avoided, the invention provides the possibility of producing by campaign, on the same plant, different qualities of (meth) acrylic acid, according to the implementation or not of the chemical treatment which ensures a certain operational flexibility for manufacturers. Other characteristics and advantages of the invention will emerge more clearly on reading the detailed description which follows, with reference to FIGS. 1 to 4, which show: FIG. 1: Installation adapted to the implementation of the recovery method of FIG. polymeric grade acrylic acid illustrating a preferred embodiment of the invention, using a conventional distillation column as a finishing column. - Figure 2: Installation adapted to the implementation of the polymer grade acrylic acid recovery process illustrating a second preferred embodiment of the invention, using a separating column distillation column as a finishing column. - Figure 3: Installation adapted to the implementation of the polymer grade acrylic acid recovery process using an additional purification section by distillation using a distillation column. - Figure 4: Installation adapted to the implementation of the polymer grade acrylic acid recovery process using an additional purification section by distillation using two distillation columns.
    DETAILED DESCRIPTION OF THE INVENTION
    For the sake of simplicity, the remainder of the presentation will refer to the production of acrylic acid, but also applies by analogy to the production of methacrylic acid. The invention aims to produce high purity acrylic acid and is based on the implementation of a treatment with a chemical agent to eliminate up to a very high level (at most a few ppm ), certain impurities still present in the technical acrylic acid obtained according to a process that does not use an external organic solvent. These include aldehydes whose presence even in trace amounts is detrimental to obtaining acrylic polymers of high molecular mass.
    According to a first aspect of the invention, the chemical treatment is integrated in a technical acrylic acid recovery process, thus directly leading to a grade of acrylic acid of polymer grade. The preferred embodiments are shown in Figures 1 and 2.
    Alternatively, according to a second aspect of the invention, the technical acrylic acid is subjected to a chemical treatment during a further treatment by distillation using one or two distillation columns, as shown in FIGS. 3 and 4.
    According to a first embodiment of the invention shown in Figure 1, a gaseous reaction mixture 1 comprising acrylic acid obtained by gas phase oxidation of a precursor of acrylic acid feeds a first distillation column 10. The gaseous reaction mixture comprising a mass ratio water / acrylic acid generally between 0.3 and 2 may be previously cooled before being subjected to dehydration according to step i) of the process according to the invention in column 10 called column dehydration.
    The reaction mixture comprises in addition to water and acrylic acid, incondensable light products such as nitrogen, oxygen, carbon monoxide and carbon dioxide, as well as various light or heavy by-products of different kinds. chemical, which may be light aldehydes such as acrolein, formaldehyde or acetaldehyde, heavy aldehydes such as furfuraldehyde or benzaldehyde, light acids such as formic acid, acetic acid or propionic acid, heavy acids such as maleic acid, benzoic acid or 2-butenoic acid.
    The dehydration column leads to a flow of the head 2, at least a part of which is condensed in a condenser 13 and returned to the dehydration column in the form of reflux 7 to absorb the acrylic acid, the other part 14/15 comprising the incondensable light compounds being generally sent partially or totally to a purification device or partly recycled to other stages of the acrylic acid production process, preferably in a stage situated upstream of the reactor for producing the reaction mixture 1.
    According to one embodiment, the entire head flow 2 of the dehydration column is sent into the head condenser 13.
    The purpose of the dehydration step i) is to remove in a head flow most of the water present in the reaction mixture, but also the incondensable light compounds and condensable light compounds. The dehydration column operates, at least partially, as a distillation column. It is fed in its lower part by the reaction mixture 1. It generates a head flow 2 comprising most of the water and light compounds, and acrylic acid and heavy compounds in a very small amount, and a Foot stream 16 depleted in light compounds comprising most of the acrylic acid with heavy byproducts.
    The dehydration column generally comprises from 5 to 50 theoretical plates, preferably from 20 to 30 theoretical plates. It is equipped with a heat exchanger whose main function, in the configuration shown in FIG. 1, is, depending on the temperature of the gas 1 entering the column, to cool or heat the liquid flow extracted from the column stand, before returning it to reflux in the lower part of the dehydration column. In another possible configuration not shown in FIG. 1, the gas stream 1 is pre-cooled in an external exchanger before entering the dehydration column, and / or the gas stream 1 is cooled and condensed at reflux of a portion of the liquid stream 16, in a heat exchanger located outside the dehydration column, before being introduced into this column.
    Advantageously, the dewatering column operates at atmospheric pressure or slightly higher, up to an absolute pressure of 1.5 105 Pa.
    Advantageously, the temperature in the upper part of the dehydration column is at least 40 ° C, preferably between 40 ° C and 80 ° C. The temperature of the foot flow of the dewatering column preferably does not exceed 120 ° C.
    According to the invention, most of the water present in the gaseous reaction mixture comprising acrylic acid is removed during step i) without there being excessive loss of acrylic acid in the reaction mixture. head flow 14/15.
    No azeotropic solvent is added to the dehydration column.
    The mass content of water in the foot flow of the dehydration column is generally less than 10%, preferably less than 7%. A typical mass composition of the foot stream of the dewatering column comprises essentially acrylic acid (84-90%), acetic acid (5-10%), water (3-6%).
    According to step ii) of the process according to the invention, the foot stream 16 of the dehydration column is sent at least partly (stream 3) at the head of a second distillation column 17, called the purification column or finishing column, in which a head flow 8 and a foot flow 9 are separated.
    According to one embodiment, a portion 20 of the liquid flow 16 of the foot of the dehydration column is sent into a heat exchanger 12 which may be a heater or a cooler and reinjected into the dehydration column, so as to constitute a loop of foot. Preferably, the portion 11 of the foot loop is reinjected between Γ supply of the reaction gas mixture and the dehydration head of the column. The remainder (stream 3) of the liquid stream 16 is fed to the finishing column 17.
    According to an optional variant of this embodiment, the flow 3 can be stored in an intermediate capacity 38 before being fed to the finishing column 17. In this option, it may be advantageous to cool the flow 3 by a heat exchanger located before the intermediate capacity, or in an exchanger located on a loop recirculation circuit in this capacity, and the cooled flow can then be reheated through an exchanger before being introduced into the purification column 17.
    The gaseous flow of the head 8 of the purification column is sent to a condenser 19. The outgoing liquid flow 4 is returned to the dehydration column, between the foot and the top of the column and preferably above the feed of the reaction gas mixture. According to one embodiment, as shown in Figure 1, it is mixed with the flow of the foot loop of the dehydration column.
    The finishing column 17 makes it possible to separate a flow of the head 8 comprising water and the condensable light by-products, a foot flow 9 comprising the bulk of the heavy by-products, in particular Michael adducts such as 3-acryloxypropionic acid, anhydride / maleic acid, benzoic acid, as well as polymerization inhibitors, and a side stream comprising purified acrylic acid in the form of liquid or vapor, gaseous preference.
    The finishing column 17 may be a conventional distillation column generally comprising from 5 to 30 theoretical plates, preferably from 8 to 20 theoretical plates. This distillation column is associated with at least one reboiler and a condenser.
    The temperature and pressure in the column 17 are not critical, and can be determined according to distillation methods known from the state of the art. However, preferably, the finishing column 17 operates at a pressure below atmospheric pressure, allowing operation at relatively low temperatures, thus avoiding the polymerization of the unsaturated products present, and minimizing the formation of heavy by-products.
    Advantageously, the finishing column operates under an absolute pressure ranging from 5 kPa to approximately 60 kPa, the temperature of the overhead stream being advantageously between 40 ° C. and approximately 90 ° C., and the temperature of the foot flow being between 60 ° C. ° C and 120 ° C.
    In the absence of the chemical treatment according to the invention, the flow of purified acrylic acid withdrawn laterally from the finishing column corresponds to a technical grade acrylic acid.
    According to a preferred configuration of the invention, a chemical agent 22 is introduced into the installation shown in FIG. 1, the introduction being able to be carried out in different ways:
    According to a first embodiment described in FIG. 1, the chemical treatment agent 22 is introduced into the finishing column 17, ie at a section located between the feed level of said column and the plateau level. lateral withdrawal, or preferably via the feed stream 3 of said column.
    According to a second embodiment not shown in FIG. 1, the chemical treatment agent is introduced into the lower part of the dewatering column at any point in the liquid flow circuit 11 returned to the column in order to cool and partially condense the hot reaction gas. The addition can be carried out upstream or downstream of the heat exchanger 12. Another option that is also possible is to send the chemical treatment agent into the stream 4 at the top of column 17 recycled to the dehydration column. The heavy products generated during the reaction of the chemical treatment agent with the aldehydes present in the flow feeding the dehydration column are removed first in the foot stream 3 of the dehydration column, then finally in the flow of dehydration. foot 9 of the finishing column, along with the other heavy by-products. The water produced by the formation reactions of these heavy products is removed partly at the top of the dewatering column, and partly at the top of the finishing column. The chemical treatment agent is a reagent which, together with the aldehydes present in the flow supplying the finishing column, forms heavy reaction products that are more easily separable from acrylic acid. The formation reactions of these heavy products produce water which is removed directly at the top of the finishing column, and the heavy products formed are removed in the bottom stream 9 of the finishing column with the other heavy by-products. .
    As a result, a stream 5 is withdrawn laterally from the finishing column in the form of a liquid stream, after condensation in an exchanger 37, of purified acrylic acid free of aldehydes, heavy compounds and non-phenolic polymerization inhibitors and also rid of water. It is therefore a flow of acrylic acid free of troublesome impurities for its subsequent polymerization, directly corresponding to a quality of acrylic acid of polymer or glacial grade, which can be used to produce the most sensitive polymer grades impurities, such as superabsorbents, without requiring additional purification, especially by fractional crystallization. This stream may then be supplemented with a polymerization inhibitor.
    The foot flow 9 of the finishing column 17 is partially returned in this column through the reboiler 18. The other part 6 can be sent to a concentration section (not shown in FIG. 1) in order to recover the residual monomeric acrylic acid contained in the stream 6, and / or sent to a cracking section to regenerate the acrylic acid from the Michael heavy addition compounds of the 3-acryloxypropionic acid type, and / or used as a raw material in an acrylic ester production unit.
    In an alternative embodiment, a second gas phase side draw is performed on the finishing column 17 (not shown in FIG. 1) at a position below the side draw off of purified acrylic acid of polymer grade. This stream, concentrated in acrylic acid, essentially free from the heavy products and reaction products of the chemical agent, may advantageously be recovered as a raw material of an esterification process for producing, for example, without limitation of choice. methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate.
    In this variant, the second stream withdrawn laterally corresponds to an ester-grade acrylic acid free of heavy byproducts which are concentrated in the foot stream 9 of the finishing column.
    According to a preferred embodiment of the invention (shown in FIG. 1), the mixture of the chemical treatment agent with the flow to be treated is produced upstream of the finishing column, in a mixing device 38 allowing the most effective dispersion of the chemical treatment agent in the flow. This device can in particular contain in series one or more capacities and one or more mixing equipment or heat exchange, so as to achieve the treatment at an optimum temperature and for a residence time. Non-exhaustively, the mixing equipment may include tools generally used by those skilled in the art for mixing liquids, such as agitated or recirculated containers or static mixers, but also any type of equipment allowing rapid dispersion. of the chemical treatment agent in the stream to be treated, such as axial jet, rotary jet, liquid jet ejectors, hydrojets, pumps, filters, etc.
    According to this embodiment, preferably, the foot flow of the dehydration column is cooled from 60-120 ° C to 30-80 ° C before or at the same time as the introduction of the chemical treatment agent. One possible device is that the foot flow of the dewatering column is cooled and stored intermediately in a stirred tank or recirculated through a pump and the introduction of the chemical treatment agent is carried out in this tank. The residence time in this intermediate capacity is generally from 5 to 120 min. Prior to feeding the finishing column with the liquid mixture from this intermediate capacity, the flow is preferably heated if necessary to a temperature of 70-90 ° C, in an in-line exchanger or a heated intermediate capacity.
    These various embodiments, and in particular that involving a mixing device, are particularly advantageous because they make it possible to reduce the amount of chemical treatment agent required and reduce the fouling of the equipment by optimizing the reactivity of the treatment agent. and thereby reducing the excess over the aldehydes to be removed.
    The chemical treatment agents that can be used in the invention can be those described in the prior art for processes combining purification by distillation and chemical treatment of aldehydes contained in a technical acrylic acid. It can be chemical agents used alone or mixed in all proportions.
    There may be mentioned in particular: • amines, such as, for example, without limitation, monoethanolamine, ethylene diamine glycine, diethylenetriamine, dipropylenetriamine, ortho-, para-, and meta-phenylenediamine., • compounds of the aniline family, such as, but not limited to, aniline, ortho-, para-, and meta-methylaniline; compounds of the hydrazine family, such as, without limitation, hydrazine and its salts, hydrazine hydrate, hydrazine sulfate, hydrazine carboxylates, hydrazine hydrochloride, phenylhydrazine, 4-nitrophenylhydrazine, and 2,4-dinitrophenylhydrazine, or aminoguanidine and its salts, such as aminoguanic hydrogen carbonate. Compounds of the family of hydrazides, such as, for example, without limitation, the hydrazides of carboxylic acids and their salts, such as the hydrazides of formic, acetic, propionic, butanoic, pentanoic and maleic acids and the dihydrazides of acids; adipic and succinic, or semicarbazide and its salts
    The chemical agents are introduced as such into the stream to be treated, or in solution in a solvent, for example in solution in acrylic acid. The chemical agent is introduced in a minimal amount to obtain a quality of glacial acrylic acid sufficiently freed of aldehyde impurities (in particular acrolein, furfuraldehyde and benzaldehyde) to meet the needs of customers. In general, the chemical agent is added in a molar ratio of from 0.5 to 10, preferably from 1 to 5, relative to all the aldehydes present in the medium to be treated.
    Referring to Figure 2 showing a variant of the invention, the finishing column 17 is replaced by a dividing wall column having two sections 35 and 36, the section 35 being fed by the foot flow 3 of the dehydration column and the polymer grade acrylic acid stream being withdrawn laterally from section 36.
    These separating columns are in particular marketed by the companies Sulzer or Montz.
    According to this embodiment, the chemical treatment agent 22 is introduced into the section 35 of the finishing column either via the feed stream 3 of said column or at a section located between the level of supplying said column in the section 35 and the bottom of this section, according to the different ways previously described in relation to a conventional column.
    The flow of the head 8 of this finishing column is condensed in the condenser 19 and returned partly to the top of the finishing column in order to ensure a liquid reflux in the section 36 delimited by the separating wall comprising the lateral withdrawal, the another part 4 being recycled in the foot loop of the dehydration column. According to this configuration, the lateral withdrawal of the flow of (meth) acrylic acid of polymer grade is carried out in gaseous phase, then is condensed in an exchanger 37 and added with polymerization inhibitor such as hydroquinone methyl ether (EMHQ). ) at a level of 200 +/- 20 ppm. Advantageously, one or more polymerization inhibitors is (are) introduced into the liquid mixture returned to reflux at the top of the column. Alternatively, the lateral withdrawal of the flow of acrylic acid of polymer grade is carried out in the liquid phase, and the purified stream is cooled in the exchanger 37. In this case, EMHQ is introduced into the liquid mixture returned to reflux. at the top of the column, in an amount such that the concentration of this inhibitor in the flow of acrylic acid of polymer grade does not exceed 220 ppm.
    According to a second aspect of the invention, no chemical treatment agent is introduced into the purification section comprising the dewatering column 10 and the finishing column 17, and the stream 5 withdrawn laterally from the finishing column in liquid form. or gaseous, then cooled or condensed in the exchanger 37, is a stream of purified acrylic acid corresponding to a technical quality.
    According to this aspect of the invention, some embodiments of which are shown in FIGS. 3 and 4, purification of technical acrylic acid from polymer-grade acrylic acid is carried out in an additional purification section comprising either a column of additional purification 21 equipped with a reboiler at the bottom and a condenser at the top (FIG. 3), ie two purification columns 29 and 21 equipped with a reboiler at the bottom and an overhead condenser (FIG. 4).
    In the configuration of FIG. 3, a chemical treatment agent 22 is introduced into the technical acrylic acid stream 5 supplying the purification column 21. The column 21 is equipped with a boiler 27 through which a part of the flow of foot of column is returned to the column, and a condenser 24 at the head. Part of the purified top stream is returned to reflux in column 21. This column is preferably operated under reduced pressure. The chemical treatment agent forms with the aldehydes present in the stream 5 heavy reaction products more easily separable from acrylic acid, which are removed in the foot stream 28 of the column 21. The water produced by the reactions The formation of these heavy products is entrained with acrylic acid in the overhead flow of the purification column 21. The overhead flow thus corresponds to a quality of glacial acrylic acid (or polymer grade) which meets the criteria of quality required for the production of polymers intended for applications for which water is not a troublesome impurity. This is the case for example for the manufacture of superabsorbents, which implement a preliminary step of dilution in water before partial neutralization and polymerization.
    In the configuration of Figure 4, the complementary purification is carried out from 2 successive columns, so as to obtain a quality of polymer grade acrylic acid having a low residual concentration of water.
    The condensed flow of technical acrylic acid is introduced into a first intermediate distillation column 29, at a location between the head and the bottom of the column, preferably at a plateau located in the upper half of column 29. The introduction of a chemical agent is carried out in the technical acrylic acid stream supplying this intermediate column 29, or at a point situated between the supply of said column and the column bottom. The water generated by the aldehyde treatment reaction is entrained with the overhead gas stream 30 of the column 29, which is then condensed in an exchanger 31 before being partly drawn off (stream 32) and partly returned to reflux. in the column.
    Stream 32 is composed essentially of acrylic acid and contains a low concentration of water. It can be returned upstream in the process or be used, for example for the manufacture of esters.
    The stream 33 obtained at the bottom of the column 29 is partly returned to the column through the boiler 34, the other part feeding a second purification column 21. At the top of this purification column 21, a liquid flow 25 is obtained. acrylic acid of polymer grade freed of water; after condensation in the exchanger 24, a portion of this liquid stream is returned to reflux in the column 21. The heavy products formed and heavy inhibitors are removed in the stream 28 at the bottom of the column 21.
    The 2 purification columns 29 and 21 are preferably operated under reduced pressure.
    The purification columns 21 and 29 may be of various configurations.
    Column 21 of the two embodiments illustrated in FIGS. 3 and 4 is a conventional distillation column generally comprising from 5 to 30 theoretical plates, preferably from 8 to 20 theoretical plates. This distillation column is associated with a reboiler and a condenser.
    The purification column 29 of the embodiment illustrated in FIG. 4 is a conventional distillation column generally comprising from 1 to 20 theoretical plates, preferably from 5 to 15 theoretical plates. This distillation column is associated with a reboiler and a condenser.
    Just like the embodiments in which the chemical treatment agent is introduced into the purification section comprising the dewatering column and the finishing column, the mixture of the flow to be treated and the chemical agent can be optionally carried out. in an intermediate capacity or a set of intermediate capacities in series, prior to its introduction in column 21 (Figure 3) or 29 (Figure 4).
    Similarly, like the particular embodiment of a purification carried out in a set comprising only two successive dehydration and finishing columns, it is possible to carry out a second lateral withdrawal in the gaseous phase on the finishing column. 17, at a position below the side draw of purified acrylic acid (technical grade). This flow corresponds to an ester grade acrylic acid free of heavy byproducts which are concentrated in the bottom stream 9 of the finishing column. It can advantageously be valorized as the raw material of an esterification process to produce different acrylic esters.
    Surprisingly, solids formation problems do not appear in the process according to the invention, whereas the mass concentration ratios of acrolein furfural present in acrylic acid streams in which chemical treatment agent is introduced, are different from those shown in EP 1110940 to prevent the generation of solid polymers. Without being bound by this explanation, the inventors believe that the chemical treatment agent is optimally introduced into a crude acrylic acid stream of composition better adapted to the solubilization of the reaction by-products (preferential embodiment carried out in an installation comprising only 2 distillation columns) or in a flow of technical acrylic acid of better quality than the technical grades available according to the conventional methods of the prior art (embodiment with chemical treatment of acrylic acid technical in an additional section).
    The process according to the invention in all its variants makes it possible to produce glacial acrylic acid or polymer grade, having a content of> 99% acrylic acid and the following impurity contents: total aldehydes <10 ppm protoanemonin <5 ppm maleic anhydride <100 ppm non-phenolic polymerization inhibitors <10 ppm The polymer grade acrylic acid purified by the process according to the invention will preferably have a content of: protoanemonin <3 ppm total aldehydes <3 ppm maleic anhydride <50 ppm non-phenolic polymerization inhibitors <3 ppm The plant according to the invention, adapted to implement the process for recovering the polymeric (meth) acrylic acid as described, comprises at least: a) a dehydration column; b) a finish column fluidly connected to the bottom of said dewatering column; c) optionally at least one distillation column fluidly connected laterally to said finishing column; d) a mixing device ensuring the introduction, mixing and optimal reaction conditions of a chemical treatment agent in the foot flow of the dewatering column feeding the finishing column, optionally comprising an intermediate capacity.
    As devices usable, there may be mentioned a stirred or recirculated container, or an in-line mixer, optionally associated with an intermediate storage capacity. The mixing device makes it possible to ensure a minimum residence time, generally between 5 minutes and 120 minutes, and to set an optimum temperature generally between 30 ° C. and 80 ° C., so that the reaction of the agent of treatment with impurities is the most effective, without causing solid deposition.
    Another subject of the invention relates to a method for producing (meth) acrylic acid of polymer grade comprising at least the following steps: A) is subjected to oxidation in the gas phase at least one precursor acid (meth) acrylic to form a gaseous reaction mixture comprising (meth) acrylic acid; B) the gaseous reaction mixture is cooled; C) the cooled gaseous reaction mixture is subjected to the (meth) acrylic acid recovery process as defined above.
    The precursor of the (meth) acrylic acid may be acrolein or methacrolein, and may be derived from renewable raw material thereby producing biosourced (meth) acrylic acid.
    Preferably, the (meth) acrylic acid is acrylic acid and the precursor of acrylic acid is acrolein obtained by catalytic oxidation of propylene.
    The oxidation reaction of step A), performed according to the state of the art, generally provides a gaseous reaction mixture, superheated at a temperature above 280 ° C.
    This mixture is advantageously cooled according to a stage B), in particular up to a temperature below 250.degree. C., preferably below 190.degree. C., to be subjected according to stage C) to the acid recovery process (meth ) acrylic without the use of an azeotropic solvent and including a chemical treatment for elimination of aldehydes. It can be cooled directly in the dewatering column, or can be cooled using a heat exchanger located upstream of the dewatering column.
    The process according to the invention provides a (meth) acrylic acid of polymer grade (or AAg) usable for preparing acrylic superabsorbents intended for the hygiene or cabling fields, or acrylic esters of high purity, or dispersants or acrylic flocculants with a low content of volatile organic compounds. The invention will now be illustrated by the following examples, which are not intended to limit the scope of the invention, defined by the appended claims.
    EXPERIMENTAL PART
    The percentages are expressed in percentages by mass.
    Example 1 (comparative)
    Simulations using the ASPEN software have been used to illustrate a method according to the prior art. It is in particular the process described in EP 2,066,613 B1 which provides side stream of the column 17, a purified flow of acrylic acid as shown in Figure 3.
    The flow rates, temperatures, pressures and compositions in main compounds of the flows are reported in the table below:
    In this table, it appears that the mass concentration ratio of furfural / acrolein is well below 3 in the stream 3, and the quality of purified acrylic acid obtained in lateral withdrawal of the column 17 (stream 5) is not of sufficient quality to be used in an application requiring a grade of polymer grade acrylic acid. In particular, the concentrations of furfural and benzaldehyde and acid / maleic anhydride are too important to manufacture polymers of high molecular weight meeting the wishes of the applicators.
    Example 2 (reference)
    A representative synthetic mixture of the medium obtained at the bottom of a dehydration column of an acrylic acid purification process that does not use an external organic solvent is prepared. This synthetic flux has the following composition: Acrylic acid (85.20%), acetic acid (10%), water (4.4%), acrolein (0.03%), furfural (0.011%), benzaldehyde (0.015%) ), maleic anhydride (0.2%), phenothiazine (0.1%), hydroquinone (0.05%). 250 g of this mixture are introduced into a glass flask and the mixture is distilled in a rotary evaporator at a temperature of 90 ° C. under a pressure of 30 mbar, so as to collect about 80% of distilled fraction.
    After evaporation, 201 g of colorless and clear distillate are collected, grading 0.01% furfural, 0.01% benzaldehyde, 0.03% acrolein, 0.15% acid / maleic anhydride.
    The results of this test reflect the partition of the impurities in the flash distillation conditions, without separation tray. It serves as a reference for the following tests carried out in the presence of chemical agents for the treatment of aldehydes.
    Example 3 (according to the invention)
    The same treatment as test 2 is repeated from 200 g of the same synthetic mixture, but this time adding 0.35 g of hydrazine hydrate. In addition, the mixture is first heated to 40 ° C for 60 minutes under atmospheric pressure, and then distilled in the rotary evaporator at a temperature of 90 ° C under a pressure of 30 mbar.
    154 g (77%) of colorless and clear distillate, recovering <lppm furfural, <lppm benzaldehyde, <lppm acrolein, <lppm acid / maleic anhydride.
    The undistilled collected residue collected after evaporation is clear and without solid deposition.
    Example 4 (according to the invention)
    The same treatment as test 3 is repeated, starting from 200 g of synthetic mixture described in test 2, but this time adding 0.31 g of aminoguanidine bicarbonate.
    After evaporation, 152 g (76%) of colorless and clear distillate, <lppm furfural, <lppm benzaldehyde, <lppm acrolein, 48ppm acid / maleic anhydride.
    The undistilled collected residue collected after evaporation is clear and without solid deposition.
    Example 5 (according to the invention)
    The same treatment as test 3 is repeated, starting from 200 g of synthetic mixture described in test 2, but this time adding 0.47 g of metaphenylenediamine.
    After evaporation, 157 g (78%) of colorless and clear distillate, titrant <lppm furfural, 3ppm benzaldehyde, <lppm acrolein, 7ppm acid / maleic anhydride.
    The undistilled collected residue collected after evaporation is clear and without solid deposition.
    Examples 3, 4 and 5 show that it is possible to obtain, from a representative flow of dehydration column bottom obtained according to a recovery / purification process without the addition of a solvent, a quality of acrylic acid of polymer grade, without additional distillation step, thanks to treatment with a chemical agent.
    权利要求:
    Claims (19)
    [1" id="c-fr-0001]
    1. Process for recovering (meth) acrylic acid of polymer grade * from a gaseous reaction mixture comprising (meth) acrylic acid obtained by gas phase oxidation of a precursor of (meth) acid acrylic, characterized in that it is implemented in an installation comprising at least two, preferably two, distillation columns in the absence of organic solvent and in the presence of at least one chemical treatment agent.
    [2" id="c-fr-0002]
    2. Process according to claim 1, characterized in that it comprises at least the following stages: i) the gaseous reaction mixture is subjected to dehydration without the use of an azeotropic solvent in a first distillation column called a dehydration column, leading to a head stream of which at least part is condensed and returned to the dehydration column as reflux, and a foot flow; ii) at least partially submitting the dehydration column foot stream to a distillation in a second column called finishing column, leading to a head flow, and to a foot stream containing heavy compounds; iii) recovering a flow of purified (meth) acrylic acid by lateral withdrawal from the finishing column;
    [3" id="c-fr-0003]
    3. Method according to claim 2 characterized in that the finishing column is a conventional distillation column operating at a pressure below atmospheric pressure.
    [4" id="c-fr-0004]
    4. Method according to claim 2 characterized in that the finishing column is a separating wall column supplied on one side of the wall by the dehydration column foot flow and the lateral withdrawal of the acid stream (meth) Purified acrylic is made in the section located on the other side of the separating wall.
    [5" id="c-fr-0005]
    5. Method according to any one of claims 2 to 4 characterized in that the chemical treatment agent is introduced into the finishing column at a section between the feed level of said column and the level of the side draw plate of purified (meth) acrylic acid.
    [6" id="c-fr-0006]
    6. Method according to any one of claims 2 to 4 characterized in that the chemical treatment agent is introduced into the finishing column through the feed stream of said column.
    [7" id="c-fr-0007]
    7. Method according to any one of claims 2 to 4 characterized in that the chemical treatment agent is introduced at the bottom of the dehydration column, preferably in the liquid stream brought into contact with the reaction stream for its cooling.
    [8" id="c-fr-0008]
    8. Process according to any one of Claims 2 to 7, characterized in that the flow of purified (meth) acrylic acid obtained in stage iii) is withdrawn in the form of a gaseous flow of (meth) acrylic acid. of polymer grade.
    [9" id="c-fr-0009]
    9. The method of claim 8 characterized in that the flow of purified (meth) acrylic acid withdrawn in step iii) is used to produce superabsorbent polymers, without requiring further purification, in particular by fractional crystallization.
    [10" id="c-fr-0010]
    10. Process according to any one of claims 2 to 4 characterized in that the flow of purified (meth) acrylic acid withdrawn in step iii) is subjected to an additional treatment by distillation, using a or two distillation columns and the introduction of the chemical treatment agent is performed during said treatment.
    [11" id="c-fr-0011]
    11. Process according to any one of the preceding claims, characterized in that the chemical treatment agent is introduced via a mixing device comprising at least one capacity ensuring the intimate mixing of the chemical agent with the flow. treat.
    [12" id="c-fr-0012]
    12. The method of claim 11 characterized in that the chemical treatment is carried out in the mixing device at a temperature between 30 ° C and 80 ° C, for a residence time ranging from 5 min to 120 min.
    [13" id="c-fr-0013]
    13. Process according to any one of the preceding claims, characterized in that the chemical treatment agent is chosen from: • amines, such as, for example, without limitation, monoethanolamine, ethylene diamine, glycine, diethylenetriamine, dipropylenetriamine, ortho-, para-, and meta-phenylenediamine. • compounds of the aniline family, such as, for example, without limitation, aniline, ortho-, para-, and meta-methylaniline; compounds of the hydrazine family, such as, but not limited to, hydrazine and its salts, hydrazine hydrate, hydrazine sulfate, hydrazine carboxylates, hydrochloride; hydrazine, phenylhydrazine, 4-nitrophenylhydrazine, and 2,4-dinitrophenylhydrazine, or alternatively aminoguanidine and its salts, such as aminoguanidine hydrogen carbonate. Compounds of the family of hydrazides, such as, for example, without limitation, the hydrazides of carboxylic acids and their salts, such as the hydrazides of formic, acetic, propionic, butanoic, pentanoic and maleic acids and the dihydrazides of acids; adipic and succinic, or semicarbazide and its salts; alone or their mixtures in all proportions.
    [14" id="c-fr-0014]
    14. Process according to any one of the preceding claims, characterized in that a second gas-phase withdrawal is carried out on the finishing column, at a position situated below the lateral withdrawal of the purified acrylic acid.
    [15" id="c-fr-0015]
    15. Process according to any one of the preceding claims, characterized in that the precursor of the (meth) acrylic acid is acrolein, obtained by oxidation of propylene or by oxyhydrogenation of propane.
    [16" id="c-fr-0016]
    16. Method according to any one of claims 1 to 14 characterized in that the precursor of (meth) acrylic acid is methacrolein obtained by oxidation of isobutylene and / or tert-butanol or from oxidation hydrogenation of butane and / or isobutane.
    [17" id="c-fr-0017]
    17. Method according to any one of claims 1 to 14 characterized in that the precursor of (meth) acrylic acid comprises carbon of renewable origin, and is derived from glycerol, 3-hydroxypropionic acid or 2-hydroxypropionic acid.
    [18" id="c-fr-0018]
    A process for producing polymeric grade (meth) acrylic acid comprising at least the following steps: A) at least one (meth) acrylic acid precursor is subjected to gas phase oxidation to form a gaseous reaction mixture comprising (meth) acrylic acid; B) the gaseous reaction mixture is cooled; C) the cooled gaseous reaction mixture is subjected to the (meth) acrylic acid recovery process as defined in any one of claims 1 to 17.
    [19" id="c-fr-0019]
    19. Installation for recovering polymer grade (meth) acrylic acid comprising at least: a) a dehydration column; b) a finish column fluidly connected to the bottom of said dewatering column; c) optionally at least one distillation column fluidly connected laterally to said finishing column; d) a mixing device ensuring the introduction, mixing and optimal reaction conditions of the chemical treatment agent in the dehydration column foot feed to the finishing column, optionally comprising an intermediate capacity.
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    同族专利:
    公开号 | 公开日
    FR3041958B1|2019-06-14|
    BR112018004525B1|2022-01-25|
    KR20180064432A|2018-06-14|
    JP2018531252A|2018-10-25|
    TW201730143A|2017-09-01|
    US20190071382A1|2019-03-07|
    WO2017060583A1|2017-04-13|
    CN108137469A|2018-06-08|
    JP6895954B2|2021-06-30|
    BR112018004525A2|2018-03-07|
    US10961179B2|2021-03-30|
    CN108137469B|2021-08-03|
    EP3359520A1|2018-08-15|
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    法律状态:
    2016-09-19| PLFP| Fee payment|Year of fee payment: 2 |
    2017-04-07| PLSC| Publication of the preliminary search report|Effective date: 20170407 |
    2017-09-18| PLFP| Fee payment|Year of fee payment: 3 |
    2018-09-13| PLFP| Fee payment|Year of fee payment: 4 |
    2019-09-13| PLFP| Fee payment|Year of fee payment: 5 |
    2020-09-14| PLFP| Fee payment|Year of fee payment: 6 |
    2021-09-13| PLFP| Fee payment|Year of fee payment: 7 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1559493A|FR3041958B1|2015-10-06|2015-10-06|IMPROVED PROCESS FOR THE PRODUCTION OF POLYMERICACRYLIC ACID|
    FR1559493|2015-10-06|FR1559493A| FR3041958B1|2015-10-06|2015-10-06|IMPROVED PROCESS FOR THE PRODUCTION OF POLYMERICACRYLIC ACID|
    BR112018004525-0A| BR112018004525B1|2015-10-06|2016-09-26|Improved process for recovering and producing polymer grade acrylic acid|
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    CN201680058532.8A| CN108137469B|2015-10-06|2016-09-26|Improved process for the preparation of polymer gradeacrylic acid|
    TW105131068A| TW201730143A|2015-10-06|2016-09-26|Improved process for the production of polymer-grade acrylic acid|
    PCT/FR2016/052434| WO2017060583A1|2015-10-06|2016-09-26|Improved process for producing polymer-grade acrylic acid|
    KR1020187011761A| KR20180064432A|2015-10-06|2016-09-26|Improved method of producing polymer gradeacrylic acid|
    EP16788151.5A| EP3359520A1|2015-10-06|2016-09-26|Improved process for producing polymer-grade acrylic acid|
    US15/765,496| US10961179B2|2015-10-06|2016-09-26|Process for producing polymer-grade acrylic acid|
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