EP1345882A2 - Procede de preparation d'acide (meth)acrylique - Google Patents

Procede de preparation d'acide (meth)acrylique

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Publication number
EP1345882A2
EP1345882A2 EP01985433A EP01985433A EP1345882A2 EP 1345882 A2 EP1345882 A2 EP 1345882A2 EP 01985433 A EP01985433 A EP 01985433A EP 01985433 A EP01985433 A EP 01985433A EP 1345882 A2 EP1345882 A2 EP 1345882A2
Authority
EP
European Patent Office
Prior art keywords
acrylic acid
stabilizer
meth
distillation apparatus
mixture
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP01985433A
Other languages
German (de)
English (en)
Inventor
Ulrich Hammon
Heinz-Friedrich Sutoris
Jürgen Schröder
Volker Schliephake
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BASF SE
Original Assignee
BASF SE
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BASF SE filed Critical BASF SE
Publication of EP1345882A2 publication Critical patent/EP1345882A2/fr
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/50—Use of additives, e.g. for stabilisation

Definitions

  • the present invention relates to a process for recycling stabilizers in the working up of (meth) acrylic acid.
  • hydroquinone or hydroquinone monomethyl ether in the presence of oxygen are listed as suitable inhibitors of the polymerization of acrylic acid in distillation columns.
  • the inhibitors used in the workup process are burned with the residue.
  • Japanese laid-open patent publication 53449/95 describes a process for inhibiting the polymerization of (meth) acrylic acid or (meth) acrylic acid esters, in which a combination of phenothiazine and hydroquinone with molecular oxygen is used in the distillation.
  • the prior art has the disadvantage that the polymerization inhibitors generally have to be added in large amounts, so that the polymerization is reduced in particular in the process steps in which (meth) acrylic acid are exposed to high temperatures.
  • a disadvantage of this recovery process is the need for an additional procedural step for the extraction.
  • DE-OS 29 01 783 describes a process for the simultaneous recovery of acrylic acid and hydroquinone, in which a bottom liquid containing predominantly acrylic acid dimer, polymerization inhibitor and high-boiling substances is subjected to degradation evaporation, in which the dimer or the acrylic acid split off from it is used as the fluid acts and so the inhibitor hydroquinone gets into the distillate.
  • the remaining residue is extracted with water to recover hydroquinone.
  • Degradation evaporation is carried out at a temperature of 120 to 220 ° C and a pressure of 2 to 50 mbar.
  • a disadvantage of this process is that in the examples the hydroquinone content in the distillate is significantly lower than in the feed liquid.
  • an extraction with water is necessary, which represents an additional procedural step.
  • stabilizers are compounds which delay and / or inhibit the polymerization of (meth) acrylic acid. These can be inhibitors, for example.
  • polymerization means an essentially radical polymerization of (meth) acrylic acid, which is essentially irreversible.
  • the polymerization can also be non-radical, e.g. anionic or cationic.
  • irreversible means that, under the reaction conditions, at most 10% by weight, often less than 5% by weight, of the polymer used is broken down into low-boiling components, e.g. Oligomers or monomers are split.
  • Polymers are those compounds that are formed by polymerization.
  • At least one stream containing stabilizer in its active form is separated from higher-boiling constituents, and this low-boiling stream is returned to a suitable point in the workup.
  • Low boilers here comprise the components which are removed in gaseous form in the distillation apparatus.
  • this stream can also contain any remaining (meth) acrylic acid and / or solvent, as well as other components such as Acrylic acid dimer included.
  • the high boilers which have been separated off can be subjected to this process a number of times, can be subjected to thermal disposal, for example, or can optionally be subjected to thermal or catalytic cleavage, the reaction output of which in turn can be subjected to the process according to the invention or disposed of.
  • the residual content of (meth) acrylic acid in the stream originating from the workup and fed to the distillation apparatus is generally at most 20% by weight, preferably at most 10% by weight and particularly preferably at most 5% by weight.
  • the solvent may have been used in a previous absorption and / or extraction and comprises the substances known to the person skilled in the art for this purpose, e.g. Water, acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid butyl ester, ethyl acetate, butyl acetate, biphenyl, diphenyl ether, orthophthalic acid dimethyl ester, orthophthalic acid diethyl ester, orthophthalic acid dibutyl ester or mixtures thereof.
  • the working up of (meth) acrylic acid comprises the absorptive, desorptive, extractive and distillative steps which are known to the person skilled in the art for separating impurities from the gas mixture of the production of (meth) acrylic acid.
  • Suitable gas mixtures are those reaction products which are formed in the catalytic gas phase oxidation of C 3 - or C 4 -alkanes, -alkenes, -alkanols and / or -alkanals and / or precursors thereof to acrylic acid or methacrylic acid by known processes.
  • the starting compounds which can be used are those from which the actual C 3 - / C 4 starting compound only forms as an intermediate during the gas phase oxidation. Examples include the production of methacrylic acid isobutyric acid or methyl tert. butyl ether.
  • the starting gases are generally diluted with inert gases such as nitrogen, C0, saturated Ci-C ö hydrocarbons and / or water vapor, in a mixture with oxygen at elevated temperatures (usually 200 to 450 ° C) and, if appropriate, increased pressure passed over transition-metallic, mixed oxide catalysts, for example containing Mo and V or Mo, W, Bi and Fe, and converted oxidatively into acrylic acid or methacrylic acid.
  • inert gases such as nitrogen, C0, saturated Ci-C ö hydrocarbons and / or water vapor
  • Particularly suitable processes for the production of methacrylic acid are those which start from methacrolein, in particular if the methacrolein is produced by gas-phase catalytic oxidation of tert-butanol, isobutane or isobutene or by reacting formaldehyde with propionaldehyde.
  • the resulting reaction gas mixture contains secondary components such as unreacted acrolein or
  • Methacrolein and / or propene or isobutene water vapor, carbon monoxide, carbon dioxide, nitrogen, oxygen, acetic acid, propionic acid, formaldehyde, further aldehydes and maleic anhydride.
  • the reaction gas mixture usually contains, based in each case on the total reaction gas mixture, 1 to 30% by weight of acrylic acid, 0.01 to 1% by weight of propene and 0.05 to 1% by weight of acrolein, 0 , 05 to 10 wt .-% oxygen, 0.01 to 3 wt .-% acetic acid, 0.01 to 2 wt .-% propionic acid, 0.05 to 1 wt .-% formaldehyde, 0.05 to 2 wt. % other aldehydes, 0.01 to 0.5% by weight of maleic acid and maleic anhydride and, as a residual amount, inert diluent gases.
  • such a gas mixture contains predominantly as a medium boiler fraction which essentially comprises the components which have a boiling point in the temperature interval in the case of acrylic acid, for example from 120 to 180 ° C., in particular in the range from, at normal pressure +/- 10 ° C around that of the product of value, ie about 131 to 151 ° C, condensed, other compounds in the high boiler and low boiler range as well as non-condensable components.
  • a medium boiler fraction which essentially comprises the components which have a boiling point in the temperature interval in the case of acrylic acid, for example from 120 to 180 ° C., in particular in the range from, at normal pressure +/- 10 ° C around that of the product of value, ie about 131 to 151 ° C, condensed, other compounds in the high boiler and low boiler range as well as non-condensable components.
  • the work-up includes the absorption of the reactor discharge with one of the solvents listed above, e.g. Biphenyl, diphenyl ether or phthalic acid ester or a mixture thereof, or water.
  • the solvents listed above e.g. Biphenyl, diphenyl ether or phthalic acid ester or a mixture thereof, or water.
  • acrylic acid is extracted with an organic solvent which may have a higher or lower boiling point than acrylic acid, e.g. Ethyl acetate, butyl acetate, ethyl acrylate, biphenyl and / or diphenyl ether.
  • the discharge of absorption can be subjected to desorption in which the absorption discharge is treated with gas in order to determine the content of volatile components, e.g. Lower acetaldehyde, propionaldehyde, acrolein or acetone.
  • volatile components e.g. Lower acetaldehyde, propionaldehyde, acrolein or acetone.
  • a distillative workup usually follows, in which acrylic acid is separated from troublesome impurities, secondary components or the solvent used. This can be one or more levels.
  • Absorption in a solvent is not absolutely necessary for the process according to the invention; it can also be used in the case of a previous fractional condensation of a reaction mixture, such as is e.g. is described in DE-A 197 40 253 or the older German application with the file number 100 53 086.9.
  • this work-up usually produces high-boiling streams, which usually contain the stabilizer (s) used in addition to polymers or oligomers.
  • Oligomers are those compounds which are formed by Michael reaction of (meth) acrylic acid with other components present in the system, e.g. diacrylic acid (3-acryloxypropionic acid), tri-, tetracrylic acid etc., di-, tri-, tetramethacrylic acid etc., 3 -Hydroxypropionic acid and hydroquinone (2 'carboxyethyl) ether.
  • Oligomers are generally at least partially, i.e. at least 20% by weight, preferably at least 30% by weight, can be split back into low-boiling components, e.g. by thermal treatment, if appropriate in the presence of a suitable catalyst, such as e.g. Benzenesulfonic acid, para-toluenesulfonic acid, xylenesulfonic acid, dodecylbenzenesulfonic acid or sulfuric acid.
  • a suitable catalyst such as e.g. Benzenesulfonic acid, para-toluenesulfonic acid, xylenesulfonic acid, dodecylbenzenesulfonic acid or sulfuric acid.
  • one or more such compounds can be used which are not volatile enough to be distillatively separated off together with the (meth) acrylic acid, i.e. those stabilizers whose content in the vapor phase under the distillation conditions is not more than 20%, preferably not more than 10%, particularly preferably not more than 5% of their content in the liquid phase supplied, but are volatile enough to be used in a suitable distillation step of contained high boilers to be separated, ie stabilizers whose content in the vapor phase under the distillation conditions is more than 5% of their content in the liquid phase supplied, preferably at least 10% and particularly preferably at least 20%.
  • these can be N-oxyls, e.g. 4-hydroxy-2, 2,6, 6-tetramethyl-piperidine-N-oxyl, 4-oxo-2, 2,6, 6-tetramethyl-piperidine-N-oxyl, 4-acetoxy-, 2 , 6, 6-tetramethyl-piperidine-N-oxyl, 2, 2, 6, 6-tetramethyl-piperidine-N-oxyl,
  • Suitable further N-oxyls are l-0xyl-2, 2, 6, 6-tetramethyl-4-methoxypiperidine, l-oxyl-2,2, 6, 6-tetramethyl-4-trimethylsilyloxypiperidine, l-0xyl -2, 2, 6, 6-tetramethyl-piperidin-4-yl-2-ethylhexanoate, l-0xyl-2, 2,6, 6-tetramethyl-piperidin-4-yl-stearate, l-0xyl-2, 2 , 6, 6-tetramethylpiperidin-4-yl-benzoate, l-oxyl-2,2, 6, 6-tetramethylpiperidin-4-yl- (4-tert-buty-dbenzoate, bis (l-oxyl-2, 2, 6, 6-tetramethyl-piperidin-4-yl) succinate, bis (l-oxyl-2, 2,6, 6-tetramethyl-piperidin-4-yl) adipate, 1, 10-decanedi
  • Suitable further phenols and naphthols are o-, m- or p-cresol (methylphenol), 2-tert-butyl-4-methylphenol, 6-tert-butyl-2,4-dimethyl-phenol, 2, 6-di-tert-butyl-4-methylphenol,
  • 1,1,4-tris (5'-tert. -Butyl-4'-hydroxy-2'-methylphen-1'-yl) utane, catechol (1,2-dihydroxybenzene), benzoquinone, 2-methyl- p-hydroquinone, 2, 3-dimethylhydroquinone, trimethylhydroquinone, 3-methylcatechol, 4-methylcatechol, tert-butylhydroc inone, 2-methoxyphenol (guaiacol, catechol monomethyl ether), 2-ethoxyphenol, 2-isopropoxyphenol -tert.-butyl-4-methoxyphenol, 4-ethoxyphenol, 4-butoxyphenol, hydroquinone monobenzyl ether, p-phenoxyphenol, 4,4'-oxydiphenyl, 3, -methylene-dioxydiphenol (sesamol), 3, 4-dimethylphenol , 3-hydroxy-4-methoxybenzyl alcohol, 2, 5-dimethoxy-4-hydroxybenzyl alcohol (Syringa alcohol), 4-
  • quinones are p-benzoquinone, tetramethyl-p-benzoquinone, diethyl-1, 4-cyclohexanedione-2, 5-dicarboxylate, phenyl-p-benzoquinone, 2, 5-dimethyl-3-benzyl-p-benzoquinone, 2 -Isopropyl-5-methyl-p-benzoquinone (Thy oquinone), 2,6-diisopropyl-p-benzoquinone, 2,5-dimethyl-3-hydroxy-p-benzoquinone, 2,5-dihydroxy-p-benzoquinone , Embelin, tetrahydroxy-p-benzoquinone, 2,5-dimethoxy-1, 4-benzoquinone, 2-arrtino-5-methyl-p-benzoquinone, 2,5-bisphenylamino-1, 4-benzoquinone, 5 , 8-Dihydroxy-l, 4-naph
  • Suitable further aromatic amines are, for example, nitrosodiethylaniline or irganox 5057 from Ciba Specialty Chemicals.
  • Suitable further phenylenediamines are N, N '-di-iso-butyl-p-phenylenediamine, N, N' -di-iso-propyl-p-phenylenediamine, p-phenylenediamine, N-phenyl-p-phenylenediamine, N , N '-diphenyl-p-phenylene-diamine, N-isopropyl-N-phenyl-p-phenylene diamine, N, N'-di-sec-butyl-p-phenylene diamine (Kerobit® BPD from BASF AG), N-phenyl -N '-isopropyl-p-phenylenediamine (Vulkanox® 4010 from Bayer AG), N- (1,3-dimethylbutyl) -N' -phenyl-p-phenylenediamine, diphenylamine, N-phenyl-2-naphthy
  • Tocopherols are also suitable, e.g. ⁇ -, ⁇ -, ⁇ -, ⁇ - and ⁇ -tocopherol, tocol, ⁇ -tocopherol hydroquinone, and 2,3-di-hydro-2,2-dimethyl-7-hydroxybenzofuran (2, 2-dimethyl-7-hydroxycu - maran).
  • these can also be degradation products or derivatives of stabilizers, for example the Michael adduct of (meth) acrylic acid and hydroquinone.
  • Stabilizers whose vapor pressures at 141 ° C. (boiling point of acrylic acid) at normal pressure are at least 15 hPa, preferably between 20 and 800 hPa, particularly preferably between 25 and 500 hPa, very particularly preferably between 25 and 250 hPa and in particular between 25, are particularly suitable and 160 hPa, and their mixtures.
  • these stabilizers can also be used in a mixture with practically non-volatile stabilizers, for example phenothiazine or inorganic salts, such as, for example, copper salts, such as, for example, copper diethyldithiocarbamate, copper diethyldithiocarbamate, copper dibutyldithiocarbamate or copper salicylate, or manganese salts, such as, for example, manganese acetate.
  • phenothiazine or inorganic salts such as, for example, copper salts, such as, for example, copper diethyldithiocarbamate, copper diethyldithiocarbamate, copper dibutyldithiocarbamate or copper salicylate, or manganese salts, such as, for example, manganese acetate.
  • stabilizer combinations such as those described in the simultaneous application "Process for the Production of Acrylic Acid” from BASF AG with the same filing date as the present application with the German file number 100 64 641.7, that is to say stabilizer combinations containing phenothiazine and at least one phenolic compound and optionally at least one metal salt which are introduced in the column head or in the region of the column head of the rectification or condensation column.
  • the fresh stabilizer added can be added individually or as a mixture in liquid, solid or dissolved form in a suitable solvent.
  • the addition can take place at any point in the workup process, for example with the quench liquid in the pre-quench or quench, in an absorption column, for example with the absorbent, the feed or at any point in the absorption column, or in a distillation column, for example with the feed, the reflux, in a cooling or quench circuit or directly in the column or at several points, such as described in WO 00/20594.
  • stabilizers can be added independently of one another at different points in the workup process. Preference is given to adding the stabilizer in distillation or absorption, particularly preferably in a distillation and very particularly preferably in a cooling or quench circuit in a distillation or metered in directly.
  • Radical polymerization is essentially reduced by the added stabilizer.
  • stabilizers can preferably act on those radicals in which the radical center is located on an oxygen atom, for example hydroquinone or hydroquinone monomethyl ether, or on those in which the radical center is on a carbon atom, for example in the case of N-oxylene or aromatic amines, or they can preferably eg decompose peroxides, eg stabilizers containing phosphorus or sulfur.
  • the process can be carried out both in the presence and in the absence of molecular oxygen (0). If it is carried out in the presence of oxygen, an oxygen-containing gas can be used in which the oxygen may be mixed with an inert gas such as carbon dioxide (C0 2 ), nitrogen (N 2 ) or noble gases such as helium or argon, or mixtures thereof is diluted. Nitrogen is preferably used for dilution.
  • an oxygen-containing gas such as carbon dioxide (C0 2 ), nitrogen (N 2 ) or noble gases such as helium or argon, or mixtures thereof is diluted. Nitrogen is preferably used for dilution.
  • the oxygen content of the oxygen-containing gas can be between 1 and 100 vol%, preferably between 2 and 80 vol%, particularly preferably between 5 and 50% and in particular between 10 and 30 vol%.
  • air is used as the oxygen-containing gas.
  • any of the inert gases listed above can be used individually or in a mixture. However, the process is preferably carried out in the presence of an oxygen-containing gas.
  • such workup streams are suitable in which the stabilizer is at least partially in its form which retards and / or inhibits the polymerization, here called the active form.
  • Such workup streams are particularly suitable in which the proportion of the stabilizer in its active form, based on the total amount of the stabilizer in its active and in its inactive form, is at least 10% by weight, particularly preferably at least 25% by weight and entirely particularly preferably at least 50% by weight.
  • the content of (active and inactive) stabilizer in the stream fed to the distillation apparatus is generally between 1 and 50,000 ppm (w / w), preferably between 5 and 30,000 ppm (w / w), particularly preferably between 20 and 20,000 ppm (f / w), very particularly preferably between 50 and 10,000 ppm (w / w) and in particular between 100 and 5000 ppm (w / w).
  • the residual content of (meth) acrylic acid in the stream fed to the distillation apparatus can be, for example, up to 50% by weight, preferably up to 40% by weight, particularly preferably up to 25% by weight and very particularly preferably up to 10% by weight.
  • Suitable distillation apparatus for the process according to the invention are all distillation apparatuses known to the person skilled in the art, e.g. Circulation evaporator, thin film evaporator, falling film evaporator, wiper blade evaporator, if necessary with attached rectification columns and stripping columns.
  • a stripping current can be applied, e.g. with nitrogen or an oxygen-containing gas, preferably with air.
  • the distillation apparatus can be at temperatures between 80 and 350 ° C, preferably between 100 and 280 ° C, particularly preferred
  • the stabilizer content in the low-boiling stream recirculated from the distillation apparatus to the work-up is generally at least 30% of the stabilizer content of the stream fed to the distillation apparatus, preferably at least
  • Suitable places for the recycling of the stream obtained from the distillation apparatus are such steps of the working up.
  • heating, evaporation, distillation, rectification or condensation for example in evaporators, distillers, condensers, quenching devices, absorbers, desorbers and return dividers.
  • a gaseous stream is recirculated from a thermal and / or catalytic fission of a high boiler stream in the same manner as a stream obtained from the still described.
  • a high-boiling stream suitable for the cleavage can be, for example, the high-boiling point of a condensation or rectification column or the distillation apparatus described above for the process according to the invention.
  • the temperature in the cleavage is generally 100 to 220 ° C, preferably 120 to 200 ° C, particularly preferably 140 to 180 ° C and in particular 150 to 180 ° C.
  • the low boilers can be separated off by passing a gas stream (stripping) which is essentially inert under the reaction conditions, e.g. Nitrogen, water vapor, but also an oxygen-containing gas, e.g. Air, are supported.
  • a gas stream e.g. Nitrogen, water vapor, but also an oxygen-containing gas, e.g. Air, are supported.
  • the remaining residue can, for example, be partially discharged, distilled or subjected to a further cleavage.
  • the gaseous stream obtained from the cleavage which in addition to low-boiling products of the cleavage, e.g. Acrylic acid, methacrylic acid or diacrylic acid, which may also contain a stabilizer, can, if appropriate after condensation and / or further cooling, be recycled to any point in the workup process, for example in quench or pre-quench, absorption, rectification or condensation column.
  • Low-boiling products of the cleavage e.g. Acrylic acid, methacrylic acid or diacrylic acid, which may also contain a stabilizer
  • the process according to the invention enables improved economy by reducing the consumption of stabilizer in the processing of (meth) acrylic acid, since the stabilizer which is still active is not disposed of, as was previously the case, but is reused in the processing, so that this process is not only economical , but also offers an ecological advantage.
  • Acrylic acid with a hydroquinone monomethyl ether content of 150 ppm by weight is distilled in a Sambay evaporator in such a way that the gas phase has a temperature as indicated in the table at the top pressure given in the table.
  • the gas phase is drained off, fully condensed and analyzed. It will be a Hydroquinone monomethyl ether (MEHQ) content found as indicated in the table.
  • MEHQ Hydroquinone monomethyl ether
  • hydroquinone monomethyl ether can be distilled together with a high-boiling solvent.
  • a mixture consisting of 99% by weight of a mixture of 75% by weight of diphenyl ether and 25% by weight of biphenyl, 1% by weight of acrylic acid and 150% by weight of hydroquinone monomethyl ether is at the same temperature as in Examples 1 to 3 in the same apparatus distilled.
  • the following contents are obtained in the condensed gas phase:
  • hydroquinone monomethyl ether can be distilled from a high-boiling solvent together with acrylic acid.
  • a mixture consisting of 99% by weight of a mixture of 75% by weight of diphenyl ether and 25% by weight of biphenyl, 1% by weight of acrylic acid and 150% by weight of phenothiazine (PTZ) is in at the same temperature as in Examples 1 to 3 distilled from the same apparatus.
  • the following contents are obtained in the condensed gas phase:
  • Comparative examples 4-6 show that phenothiazine cannot be distilled from acrylic acid from a high-boiling solvent.

Abstract

La présente invention concerne un procédé permettant la préparation d'acide (méth)acrylique en présence d'au moins un agent de stabilisation. Selon l'invention, un mélange contenant l'agent de stabilisation, sensiblement dépourvu d'acide (méth)acrylique, résultant de la préparation, est introduit dans un appareil de distillation et une courant à bas point d'ébullition contenant l'agent de stabilisation obtenu à partir dudit mélange, est réintroduit dans le processus de préparation.
EP01985433A 2000-12-22 2001-12-21 Procede de preparation d'acide (meth)acrylique Withdrawn EP1345882A2 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10064642 2000-12-22
DE10064642A DE10064642A1 (de) 2000-12-22 2000-12-22 Verfahren zur Herstellung von (Meth)acrylsäure
PCT/EP2001/015206 WO2002051786A2 (fr) 2000-12-22 2001-12-21 Procede de preparation d'acide (meth)acrylique

Publications (1)

Publication Number Publication Date
EP1345882A2 true EP1345882A2 (fr) 2003-09-24

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Country Status (7)

Country Link
US (1) US20040050679A1 (fr)
EP (1) EP1345882A2 (fr)
JP (1) JP2004516307A (fr)
CN (1) CN1215035C (fr)
BR (1) BR0116290A (fr)
DE (1) DE10064642A1 (fr)
WO (1) WO2002051786A2 (fr)

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TWI344469B (en) * 2005-04-07 2011-07-01 Nippon Catalytic Chem Ind Polyacrylic acid (salt) water-absorbent resin, production process thereof, and acrylic acid used in polymerization for production of water-absorbent resin
DE102005057894A1 (de) * 2005-12-02 2007-06-06 Basf Ag Stabilisierte polymerisierbare Mischungen
TWI394789B (zh) 2005-12-22 2013-05-01 Nippon Catalytic Chem Ind 吸水性樹脂組成物及其製造方法、吸收性物品
EP1837348B9 (fr) 2006-03-24 2020-01-08 Nippon Shokubai Co.,Ltd. Résine absorbant l'eau et son procédé de fabrication
DE102008000237A1 (de) 2007-02-06 2008-08-07 Basf Se Phenol-Imidazolderivate zur Stabilisierung von polymerisationsfähigen Verbindungen
CN102548654A (zh) 2009-09-29 2012-07-04 株式会社日本触媒 颗粒状吸水剂及其制造方法
DE102009058058A1 (de) * 2009-12-14 2011-06-16 Basf Se Verfahren zur Polymerisationsinhibierung von (Meth)acrylsäure und/oder Meth)acrylsäureestern
KR101760044B1 (ko) * 2014-12-09 2017-07-20 주식회사 엘지화학 (메트)아크릴산의 연속 회수 방법

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JPS506449B1 (fr) * 1969-06-24 1975-03-14
JPS6059889B2 (ja) * 1977-09-28 1985-12-27 株式会社日本触媒 ハイドロキノンの回収方法
US4317926A (en) * 1978-01-19 1982-03-02 Nippon Shokubai Kagaku Kogyo Co., Ltd. Process for preparing and recovering acrylic acid

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Publication number Publication date
WO2002051786A2 (fr) 2002-07-04
WO2002051786A3 (fr) 2003-01-23
US20040050679A1 (en) 2004-03-18
DE10064642A1 (de) 2002-06-27
CN1489571A (zh) 2004-04-14
JP2004516307A (ja) 2004-06-03
BR0116290A (pt) 2004-03-02
CN1215035C (zh) 2005-08-17

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