WO2009130842A1 - Method for breaking down urea compounds - Google Patents

Method for breaking down urea compounds Download PDF

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Publication number
WO2009130842A1
WO2009130842A1 PCT/JP2009/001132 JP2009001132W WO2009130842A1 WO 2009130842 A1 WO2009130842 A1 WO 2009130842A1 JP 2009001132 W JP2009001132 W JP 2009001132W WO 2009130842 A1 WO2009130842 A1 WO 2009130842A1
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water
urea compound
residue
urea
isocyanate
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PCT/JP2009/001132
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French (fr)
Japanese (ja)
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古川睦久
小椎尾謙
本九町卓
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日本ポリウレタン工業株式会社
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Priority to JP2010509045A priority Critical patent/JP5240678B2/en
Publication of WO2009130842A1 publication Critical patent/WO2009130842A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C08J11/14—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by treatment with steam or water
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
    • C08J2375/02—Polyureas
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling

Definitions

  • the present invention relates to a method for decomposing a urea compound, in which polyurea is hydrolyzed in supercritical or subcritical carbon dioxide to recover the corresponding amine.
  • Polyurethane is a polymer material synthesized by polyaddition reaction of polyisocyanate and polyol. Polyurethane can be imparted with various physical properties by blending, formulation, molding method and the like. For this reason, it is used in a wide variety of forms such as foams, elastomers, paints, and adhesives.
  • Isocyanate which is a raw material of polyurethane, is obtained by reacting a corresponding amine with phosgene, but a urea residue is generated as a by-product at this time.
  • This residue is a tar-like substance that solidifies at room temperature and is difficult to handle, so that it has conventionally been a waste that is exclusively incinerated.
  • Patent Document 1 proposes a method of treating urea residue using supercritical or subcritical water.
  • An object of the present invention is to recover a reusable polyamine without adding a hydrolysis accelerator such as an alkali to a urea residue produced as a by-product at the time of producing an isocyanate, which until now has been disposed of, and a reactor. It is an object of the present invention to provide a method for decomposing a urea compound without causing the corrosive problem.
  • a hydrolysis accelerator such as an alkali
  • the present inventors have made it possible to hydrolyze the urea residue by-produced during the production of isocyanate in carbon dioxide in a supercritical state or subcritical state, thereby improving the efficiency of the polyamine.
  • the present invention has been completed by finding a suitable recovery and suitable conditions therefor. That is, the present invention is shown in the following (1) to (3).
  • a method for decomposing a urea compound comprising hydrolyzing a urea compound in carbon dioxide in a supercritical state or a subcritical state using water in a liquid or gaseous state and recovering the corresponding amine.
  • the urea compound is not particularly limited as long as it is a compound having a group -NH-CO-NH- (urea group), and includes those in which a part of the urea group is a biuret group.
  • a specific urea compound is mainly produced as a residue produced as a by-product during isocyanate production.
  • the term “residue” means a residue generated during the production of a compound having at least one —NCO group such as monoisocyanate and diisocyanate described below.
  • Examples of the monoisocyanate include aliphatic monoisocyanates and aromatic monoisocyanates represented by the general formula R—NCO (where R is an aliphatic group or an aromatic group).
  • aliphatic monoisocyanate examples include methyl isocyanate and n-butyl isocyanate.
  • aromatic monoisocyanate examples include phenyl isocyanate.
  • diisocyanate examples include aliphatic diisocyanates, aromatic diisocyanates, and alicyclic diisocyanates represented by the general formula OCN-R-NCO (R is the above group or alicyclic group).
  • aliphatic diisocyanate examples include hexamethylene diisocyanate.
  • aromatic diisocyanate examples include xylylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, and diphenylmethane diisocyanate.
  • alicyclic diisocyanate examples include isophorone diisocyanate and norbornene diisocyanate.
  • the urea compound used in the decomposition of the present invention may be generated in any step as long as it remains as a by-product during isocyanate production. Specifically, it is a residue produced as a by-product in any of an amine production process, an amine-phosgene reaction process, an isocyanate purification process, an isocyanate recovery process, and the like. These residues may be melted and dissolved in each step. In addition, it is not limited to the isocyanate manufactured using phosgene as a residue applicable to this invention, When manufacturing by a non-phosgene method, it can decompose
  • any residue may be used, but it is usually used after the residue generated in each step is separated from the liquid component by a solid-liquid separation step, a distillation step or the like. What passed through the refinement
  • purification process of isocyanate is preferable.
  • the distillation residue that is, a purification distillation step of the isocyanate
  • the one recovered from the distillation residue until it does not substantially contain a volatile component is particularly preferable.
  • the residue by-produced during the production of these isocyanates is a mixture mainly composed of thermal polycondensates such as amines and isocyanates.
  • the thermal polycondensate has groups or rings such as urea (urethane), biuret, carbodiimide, isocyanurate and the like. In particular, many compounds having a complicated structure having a plurality of these groups or rings are contained.
  • the urea compound such as the above residue is hydrolyzed to the corresponding amine in supercritical or subcritical carbon dioxide.
  • the pressure during hydrolysis is preferably 5 to 10 MPa from the viewpoint of decomposition efficiency.
  • the temperature during hydrolysis is preferably 170 ° C. or higher and lower than 374 ° C., particularly preferably 180 to 250 ° C.
  • the decomposition time of the urea compound is not particularly limited, but is 1 minute to 300 minutes, preferably 1 minute to 150 minutes after reaching a predetermined temperature.
  • the mixing and heating of water and the urea compound may be performed by any of the following methods, but 3) is preferable.
  • 1) Water and a urea compound are mixed at a predetermined temperature.
  • 2) Water is heated to a predetermined temperature when mixed with the urea compound, and the decomposition temperature is set by mixing the heated water and the urea compound.
  • 3) Water and a urea compound are mixed in advance at a predetermined concentration in a slurry preparation drum or the like to prepare a slurry, and then heated to a decomposition temperature.
  • the amine corresponding to the isocyanate is contained as a main component, and the corresponding amine can be easily obtained by a usual method such as distillation or extraction. Can be recovered. The recovered amine is further purified if necessary, and then recycled as a raw material to the isocyanate production process to be reacted with phosgene.
  • a light boiling component mainly composed of carbon dioxide is dissolved in the aqueous solution from which the amine is separated. After removing it by performing steam stripping or the like, it can be used for hydrolysis without removing it. It can also be recycled as water. Or it can also drain after carrying out normal wastewater treatment.
  • the distillation residue at the time of isocyanate production may be any distillation residue generated by distillation in any step of the isocyanate production facility. Usually, it is produced mainly by distillation of a reaction solution obtained in an amine production step or a step of reacting an amine with a carbonyl source such as phosgene.
  • this distillation residue is usually liquid and contains several tens of percent, for example, 10 to 50 wt% of volatile components.
  • examples of an apparatus for recovering from the above distillation residue to a state that does not substantially contain a volatile component include those used in a normal volatile recovery process such as a thin film evaporator, an apparatus having a stirring and heating means such as a kneader. .
  • a two-phase flow evaporator having piston flow properties it is particularly preferable to use a two-phase flow evaporator having piston flow properties.
  • the evaporation device having piston flow means a facility through which an evaporation target flows in a certain direction from upstream to downstream of the device.
  • the two-phase flow type evaporator is an evaporator having at least a gas-liquid or gas-solid two-phase flow, and gas-liquid-solid three phases may coexist.
  • Typical examples of these include kneaders and double tube heat exchangers.
  • a tubular evaporator that forms at least one of a wavy flow, a slag flow, an annular flow, and a spray flow is particularly preferable.
  • An apparatus in which the flow state is formed by a gas generated inside the evaporation apparatus is most preferable, and for example, a double tube heat exchanger or the like is suitably used.
  • FT-IR measurement condition equipment FTS3000 type FT-IR measurement device (manufactured by Bio-Rad) Measurement method: KBr method detector: MCT Measurement range: 400 to 4000 cm -1 Sensitivity: 2 Resolution: 4cm -1 Integration count: 32 times 1 H-NMR measurement conditions Solvent: CDCl 3 Measuring apparatus: Superconducting multi-nuclide magnetic resonance apparatus JNM-GC400 (manufactured by JEOL Ltd.) Integration count: 8 times
  • Examples 5 to 9 a graph with the vertical axis representing the decomposition rate and the horizontal axis representing the pressure is shown in FIG. From FIG. 4, Examples 6 to 8 were the best (decomposition rate 100%). Under a constant temperature, the density of carbon dioxide increases as the pressure of carbon dioxide increases. It is thought that the diffusion level of carbon dioxide is low at low pressure, and the diffusion level of water is low at high pressure. From this result, it was found that the optimum range of internal pressure was 5 to 10 MPa.
  • 1 is a 1 H-NMR chart of methanol-soluble matter. It is a decomposition

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  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
  • Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)

Abstract

Provided is a method for breaking down polyurea without adding a hydrolysis promoter such as alkali to the by-product urea residue obtained when producing isocyanate, material which has only been treated as waste in the past. Reusable polyamine can be recovered and there is no problem with corrosion of the reaction apparatus. The urea compound is broken down by hydrolysis in carbon dioxide in the super-critical state or the sub-critical state. The pressure during hydrolysis is preferably from 5 to 10 MPa and the water/reaction vessel volume ratio is preferably from 10/100 to 30/100.

Description

ウレア化合物の分解処理方法Method for decomposing urea compounds
　本発明は、超臨界状態又は亜臨界状態の二酸化炭素中でポリウレアを加水分解して対応するアミンを回収する、ウレア化合物の分解処理方法に関する。 The present invention relates to a method for decomposing a urea compound, in which polyurea is hydrolyzed in supercritical or subcritical carbon dioxide to recover the corresponding amine.
　ポリウレタンは、ポリイソシアネートとポリオールとの重付加反応により合成される高分子材料である。ポリウレタンは、配合、処方、成形方法等により、種々の物性を付与することが可能である。このため、フォーム、エラストマー、塗料、接着剤等多種多様に利用されている。 Polyurethane is a polymer material synthesized by polyaddition reaction of polyisocyanate and polyol. Polyurethane can be imparted with various physical properties by blending, formulation, molding method and the like. For this reason, it is used in a wide variety of forms such as foams, elastomers, paints, and adhesives.
　ポリウレタンの原料であるイソシアネートは、対応するアミンをホスゲンと反応させることにより得られているが、この際の副生成物として、ウレア残さが生成する。この残さは、常温下で固化するタール状の物質であり、ハンドリングが難しいため、従来はもっぱら焼却処理される廃棄物であった。 Isocyanate, which is a raw material of polyurethane, is obtained by reacting a corresponding amine with phosgene, but a urea residue is generated as a by-product at this time. This residue is a tar-like substance that solidifies at room temperature and is difficult to handle, so that it has conventionally been a waste that is exclusively incinerated.
　この残さを分解・回収する方法として、超臨界状態又は亜臨界状態の水を用いてウレア残さを処理する方法が特許文献１に提案されている。 As a method for decomposing and recovering this residue, Patent Document 1 proposes a method of treating urea residue using supercritical or subcritical water.
特開２０００－１３６２６４号公報JP 2000-136264 A
　しかしながら、特許文献１の方法では、超臨界状態又は亜臨界状態の水とするためには、高温（臨界温度＝３７４℃）・高圧（臨界圧力＝２２．１ＭＰａ）のという過酷な条件が必要であるため、重厚な設備を必要とする。また超臨界状態又は亜臨界状態の水は、金属腐食の問題を内包しており、反応容器他の装置の維持管理が煩雑となる。 However, the method of Patent Document 1 requires harsh conditions such as high temperature (critical temperature = 374 ° C.) and high pressure (critical pressure = 22.1 MPa) in order to obtain supercritical or subcritical water. Therefore, heavy equipment is required. Further, water in a supercritical state or a subcritical state contains a problem of metal corrosion, and the maintenance of the reaction vessel and other devices becomes complicated.
　本発明の目的は、これまで廃棄処分するしかなかったイソシアネート製造時に副生するウレア残さに、アルカリ等の加水分解促進剤を添加することなく、再利用可能なポリアミンを回収でき、また、反応装置の腐食性の問題を起こすことのないウレア化合物の分解処理方法を提供することにある。 An object of the present invention is to recover a reusable polyamine without adding a hydrolysis accelerator such as an alkali to a urea residue produced as a by-product at the time of producing an isocyanate, which until now has been disposed of, and a reactor. It is an object of the present invention to provide a method for decomposing a urea compound without causing the corrosive problem.
そこで本発明者らは上記課題を解決するべく鋭意検討した結果、イソシアネート製造時に副生するウレア残さを、超臨界状態又は亜臨界状態の二酸化炭素中にて、加水分解させることにより、ポリアミンの効率的な回収、及びそのための好適条件を見い出し、本発明を完成するに至った。すなわち本発明は、以下の（１）～（３）に示されるものである。 Thus, as a result of intensive studies to solve the above problems, the present inventors have made it possible to hydrolyze the urea residue by-produced during the production of isocyanate in carbon dioxide in a supercritical state or subcritical state, thereby improving the efficiency of the polyamine. The present invention has been completed by finding a suitable recovery and suitable conditions therefor. That is, the present invention is shown in the following (1) to (3).
（１）　ウレア化合物を超臨界状態又は亜臨界状態の二酸化炭素中、液体または気体状態の水を用いて加水分解して、対応するアミンを回収することを特徴とする、ウレア化合物の分解処理方法。 (1) A method for decomposing a urea compound, comprising hydrolyzing a urea compound in carbon dioxide in a supercritical state or a subcritical state using water in a liquid or gaseous state and recovering the corresponding amine. .
（２）　加水分解時の圧力が５～１０ＭＰａであることを特徴とする、前記（１）のウレア化合物の分解処理方法。 (2) The method for decomposing a urea compound according to (1) above, wherein the pressure during hydrolysis is 5 to 10 MPa.
（３）　水と反応容器との容積比が、水／反応容器＝１０／１００～３０／１００であることを特徴とする、前記（１）、（２）のウレア化合物の分解処理方法。 (3) The method for decomposing a urea compound according to (1) or (2) above, wherein the volume ratio of water to the reaction vessel is water / reaction vessel = 10/100 to 30/100.
（４）　回収されるアミンが、ジフェニルメタンジアミンであることを特徴とする、前記（１）～（３）のいずれかのウレア化合物の分解処理方法。 (4) The method for decomposing a urea compound according to any one of (1) to (3) above, wherein the recovered amine is diphenylmethanediamine.
　本発明の方法によれば、従来産業廃棄物として処分されていたイソシアネートの残さをアルカリ等の添加剤を使うことなく、残さに対応するアミンに効率よく変換することが可能となった。 According to the method of the present invention, it is possible to efficiently convert an isocyanate residue, which has been disposed of as industrial waste, into an amine corresponding to the residue without using an additive such as an alkali.
　本発明において、ウレア化合物とは、－ＮＨ－ＣＯ－ＮＨ－なる基（ウレア基）を有する化合物であれば特に制限はなく、また前記ウレア基の一部がビウレット基となっているものも含む。具体的なウレア化合物は、主にイソシアネート製造時に副生する残さとして生成するものである。また残さとは、下記モノイソシアネート、ジイソシアネート等の少なくとも一つの－ＮＣＯ基を有する化合物の製造時に発生する残さを意味する。 In the present invention, the urea compound is not particularly limited as long as it is a compound having a group -NH-CO-NH- (urea group), and includes those in which a part of the urea group is a biuret group. . A specific urea compound is mainly produced as a residue produced as a by-product during isocyanate production. The term “residue” means a residue generated during the production of a compound having at least one —NCO group such as monoisocyanate and diisocyanate described below.
　モノイソシアネートとしては、例えば一般式Ｒ－ＮＣＯ（Ｒは脂肪族基又は芳香族基）で示される脂肪族モノイソシアネート、芳香族モノイソシアネート等が挙げられる。 Examples of the monoisocyanate include aliphatic monoisocyanates and aromatic monoisocyanates represented by the general formula R—NCO (where R is an aliphatic group or an aromatic group).
　脂肪族モノイソシアネートの具体例としては、メチルイソシアネート、ｎ－ブチルイソシアネート等を挙げることができる。又芳香族モノイソシアネートの具体例としてはフェニルイソシアネート等を挙げることができる。 Specific examples of the aliphatic monoisocyanate include methyl isocyanate and n-butyl isocyanate. Specific examples of the aromatic monoisocyanate include phenyl isocyanate.
　ジイソシアネートとしては一般式ＯＣＮ－Ｒ－ＮＣＯ（Ｒは上記の基又は脂環基）で示される脂肪族ジイソシアネート、芳香族ジイソシアネート、脂環式ジイソシアネート等が挙げられる。 Examples of the diisocyanate include aliphatic diisocyanates, aromatic diisocyanates, and alicyclic diisocyanates represented by the general formula OCN-R-NCO (R is the above group or alicyclic group).
　脂肪族ジイソシアネートの具体例としてはヘキサメチレンジイソシアネート等を挙げることができる。芳香族ジイソシアネートとしては、キシリレンジイソシアネート、トリレンジイソシアネート、ナフチレンジイソシアネート、ジフェニルメタンジイソシアネート等を挙げることができる。脂環式ジイソシアネートとしては、イソホロンジイソシアネート、ノルボルネンジイソシアネート等を挙げることができる。上記イソシアネート以外、例えばトリイソシアネート等の３以上の－ＮＣＯ基を有するイソシアネート化合物の製造時に副生する残さをも用いることができる。本発明の分解に用いられるウレア化合物としてはイソシアネート製造時に副生する残さであればいずれの工程で発生したものでもよい。具体的には、アミン製造工程、アミンとホスゲンの反応工程、イソシアネート精製工程又はイソシアネートを回収する工程等のいずれかで副生する残さである。これら残さは各工程においては溶融、溶解していてもよい。なお本発明に適用できる残さとしてはホスゲンを用いて製造されるイソシアネートには限定されず、非ホスゲン法で製造する場合それらの各工程のいずれかの工程で副生する残さをも分解することができることは言うまでもない。 Specific examples of the aliphatic diisocyanate include hexamethylene diisocyanate. Examples of the aromatic diisocyanate include xylylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, and diphenylmethane diisocyanate. Examples of the alicyclic diisocyanate include isophorone diisocyanate and norbornene diisocyanate. In addition to the above isocyanates, residues produced as a by-product during the production of isocyanate compounds having three or more —NCO groups such as triisocyanate can also be used. The urea compound used in the decomposition of the present invention may be generated in any step as long as it remains as a by-product during isocyanate production. Specifically, it is a residue produced as a by-product in any of an amine production process, an amine-phosgene reaction process, an isocyanate purification process, an isocyanate recovery process, and the like. These residues may be melted and dissolved in each step. In addition, it is not limited to the isocyanate manufactured using phosgene as a residue applicable to this invention, When manufacturing by a non-phosgene method, it can decompose | disassemble the residue byproduced in any one of those processes. Needless to say, you can.
　残さとしてはいずれを用いても良いが通常、各工程で発生した残さを固液分離工程、蒸留工程等により液状成分と分離した後に用いられる。イソシアネートの精製工程を経たものが好ましい。特に蒸留によってイソシアネートを精製する場合はその蒸留残さ（即ちイソシアネートの精製蒸留工程）が好ましく、それらの蒸留残さから揮発成分を実質的に含有しないまでに回収したものが特に好ましい。 Any residue may be used, but it is usually used after the residue generated in each step is separated from the liquid component by a solid-liquid separation step, a distillation step or the like. What passed through the refinement | purification process of isocyanate is preferable. In particular, when the isocyanate is purified by distillation, the distillation residue (that is, a purification distillation step of the isocyanate) is preferable, and the one recovered from the distillation residue until it does not substantially contain a volatile component is particularly preferable.
　これらイソシアネート製造時に副生する残さは主としてアミン、イソシアネート等の熱重縮合物からなる混合物である。熱重縮合物は例えばウレア（ウレタン）、ビウレット、カルボジイミド、イソシアヌレート等の基又は環を有している。特にこれらの基又は環を
複数有する複雑な構造を有する化合物が多く含有されている。 The residue by-produced during the production of these isocyanates is a mixture mainly composed of thermal polycondensates such as amines and isocyanates. The thermal polycondensate has groups or rings such as urea (urethane), biuret, carbodiimide, isocyanurate and the like. In particular, many compounds having a complicated structure having a plurality of these groups or rings are contained.
　上記の残さのようなウレア化合物は、超臨界又は亜臨界状態の二酸化炭素中で、対応するアミンに加水分解される。加水分解時の圧力は、分解効率の点から５～１０ＭＰａであることが好ましい。また、加水分解時の温度は１７０℃以上３７４℃未満が好ましく、特に１８０～２５０℃が好ましい。 The urea compound such as the above residue is hydrolyzed to the corresponding amine in supercritical or subcritical carbon dioxide. The pressure during hydrolysis is preferably 5 to 10 MPa from the viewpoint of decomposition efficiency. The temperature during hydrolysis is preferably 170 ° C. or higher and lower than 374 ° C., particularly preferably 180 to 250 ° C.
　加水分解の際の水と反応容器との容積比は、分解効率の点から水／反応容器＝１０／１００～３０／１００であることが好ましい。水の量が少なすぎる場合は、ウレア化合物への水の拡散が不十分となり、水が多すぎる場合は二酸化炭素の拡散が不十分になると思われる。 The volume ratio of water to the reaction vessel during hydrolysis is preferably water / reaction vessel = 10/100 to 30/100 from the viewpoint of decomposition efficiency. If the amount of water is too small, the diffusion of water into the urea compound will be insufficient, and if there is too much water, the diffusion of carbon dioxide will be insufficient.
　また、ウレア化合物と水の質量比は、水／ウレア化合物＝２０／１～１６０／１が好ましく、特に４０／１～８０／１が特に好ましい。水の量が少なすぎる場合は、ウレア化合物への水の拡散が不十分となり、水が多すぎる場合は二酸化炭素の拡散が不十分になると思われる。 The mass ratio of the urea compound to water is preferably water / urea compound = 20/1 to 160/1, particularly preferably 40/1 to 80/1. If the amount of water is too small, the diffusion of water into the urea compound will be insufficient, and if there is too much water, the diffusion of carbon dioxide will be insufficient.
　ウレア化合物の分解時間は、特に制限されないが、所定温度に達した後、１分～３００分、好ましくは１分～１５０分の範囲で行う。 The decomposition time of the urea compound is not particularly limited, but is 1 minute to 300 minutes, preferably 1 minute to 150 minutes after reaching a predetermined temperature.
　水と、ウレア化合物の混合加熱は、以下のいずれの方法によってもよいが、３）が好ましい。
１）水とウレア化合物とを予め所定の温度にしておいて混合する。
２）水を、ウレア化合物と混合したときに所定温度になるように加熱しておき、加熱された水とウレア化合物とを混合することにより分解温度とする。
３）水とウレア化合物を予めスラリー調製ドラム等において所定濃度になるように混合してスラリーを調製した後、分解温度まで加熱する。 The mixing and heating of water and the urea compound may be performed by any of the following methods, but 3) is preferable.
1) Water and a urea compound are mixed at a predetermined temperature.
2) Water is heated to a predetermined temperature when mixed with the urea compound, and the decomposition temperature is set by mixing the heated water and the urea compound.
3) Water and a urea compound are mixed in advance at a predetermined concentration in a slurry preparation drum or the like to prepare a slurry, and then heated to a decomposition temperature.
　このようにしてウレア化合物を分解して得られた水溶液中には、イソシアネートに対応するアミンが主成分として含まれていることは言うまでもなく、対応するアミンを通常の蒸留や抽出等の方法によって容易に回収することができる。回収されたアミンは、必要によりさらに精製されたのち、イソシアネート製造工程に原料として循環され、ホスゲンと反応させられる。 In the aqueous solution obtained by decomposing the urea compound in this way, it goes without saying that the amine corresponding to the isocyanate is contained as a main component, and the corresponding amine can be easily obtained by a usual method such as distillation or extraction. Can be recovered. The recovered amine is further purified if necessary, and then recycled as a raw material to the isocyanate production process to be reacted with phosgene.
　アミンが分離された水溶液中には二酸化炭素を主成分とする軽沸点成分が溶解しているが、これをスチームストリッピング等を実施することにより除去したのち、あるいは除去することなく、加水分解用の水として循環使用することもできる。あるいは、通常の廃水処理をしたのち排水することもできる。 In the aqueous solution from which the amine is separated, a light boiling component mainly composed of carbon dioxide is dissolved. After removing it by performing steam stripping or the like, it can be used for hydrolysis without removing it. It can also be recycled as water. Or it can also drain after carrying out normal wastewater treatment.
　イソシアネート製造時の蒸留残さとは、イソシアネートの製造設備のいずれかの工程において蒸留することによって発生した蒸留残さであればいずれでもよい。通常、主にアミン製造工程又はアミンとカルボニル源例えばホスゲンとを反応する工程で得られた反応液を蒸留することにより生じる。 The distillation residue at the time of isocyanate production may be any distillation residue generated by distillation in any step of the isocyanate production facility. Usually, it is produced mainly by distillation of a reaction solution obtained in an amine production step or a step of reacting an amine with a carbonyl source such as phosgene.
　この蒸留残さの副生量はその製造方法によって異なるが、一般的には精製蒸留塔の塔頂部から抜き出されるイソシアネートに対して約１０ｗｔ％程度の量である。この蒸留残さは通常液状であり、揮発成分を数１０％、例えば１０～５０ｗｔ％含有している。 Although the amount of by-products of this distillation residue varies depending on the production method, it is generally about 10 wt% with respect to the isocyanate extracted from the top of the purification distillation column. This distillation residue is usually liquid and contains several tens of percent, for example, 10 to 50 wt% of volatile components.
　本発明において、上記蒸留残さから揮発成分を実質的に含有しない状態までに回収する装置としては薄膜蒸発器、ニーダー等攪拌及び加熱手段を有する装置等通常の揮発回収工程において用いられるものが挙げられる。これらの中で特にピストンフロー性を有する二
相流型蒸発装置を用いることが好ましい。 In the present invention, examples of an apparatus for recovering from the above distillation residue to a state that does not substantially contain a volatile component include those used in a normal volatile recovery process such as a thin film evaporator, an apparatus having a stirring and heating means such as a kneader. . Among these, it is particularly preferable to use a two-phase flow evaporator having piston flow properties.
　ピストンフロー性を有する蒸発装置とは、装置の上流から下流への一定方向に向かって被蒸発体が流れる設備のことを意味する。二相流型蒸発装置とは、少なくとも気液、気固のいずれかの二相の流れを有する蒸発装置であり、気液固の三相が共存してもよい。 The evaporation device having piston flow means a facility through which an evaporation target flows in a certain direction from upstream to downstream of the device. The two-phase flow type evaporator is an evaporator having at least a gas-liquid or gas-solid two-phase flow, and gas-liquid-solid three phases may coexist.
　これらの代表例としてはニーダーや二重管型熱交換器等が挙げられる。これらのなかでも波状流、スラグ流、環状流、噴霧流の少なくともいずれか一つの流動状態を形成する管型蒸発装置が特に好ましい。前記流動状態が蒸発装置内部で発生する気体により形成される装置が最も好ましく、例えば二重管型熱交換器等が好適に用いられる。 Typical examples of these include kneaders and double tube heat exchangers. Among these, a tubular evaporator that forms at least one of a wavy flow, a slag flow, an annular flow, and a spray flow is particularly preferable. An apparatus in which the flow state is formed by a gas generated inside the evaporation apparatus is most preferable, and for example, a double tube heat exchanger or the like is suitably used.
　以下実施例により本発明を更に詳細に説明するが、下記実施例は本発明を何等制限するものではない。 Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples do not limit the present invention in any way.
〔ウレア化合物の合成〕
　メカニカルスターラーをつけたセパラブルフラスコ中で、４，４′－ジフェニルメタンジイソシアネート（ＭＤＩ）を６８．７ｇをジメチルホルムアミド（ＤＭＦ）４０ｍｌに溶解させた。ＭＤＩのＤＭＦ溶液を撹拌しながら、蒸留水５．０ｇ／ＤＭＦ８０ｍｌの混合液を、滴下ロートを用いて、室温にて３０分かけてＭＤＩのＤＭＦ溶液に加えた。その後、８０℃のオイルバスにて１８時間、撹拌しながら加熱混合を続けた。加熱後、反応液は乳濁した沈殿物を生じた。これを濾過し、濾物をアセトンとメタノールにて数回洗浄した後、減圧乾燥して、白色粉末状のウレア化合物を得た。このウレア化合物は、ＤＭＦ、ジメチルスホキシド（ＤＭＳＯ）、メタノール、クロロホルムには溶解しなかった。 [Synthesis of urea compounds]
In a separable flask equipped with a mechanical stirrer, 68.7 g of 4,4′-diphenylmethane diisocyanate (MDI) was dissolved in 40 ml of dimethylformamide (DMF). While stirring the DMF solution of MDI, a mixed solution of 5.0 g of distilled water / 80 ml of DMF was added to the DMF solution of MDI using a dropping funnel over 30 minutes at room temperature. Thereafter, heating and mixing were continued with stirring in an oil bath at 80 ° C. for 18 hours. After heating, the reaction solution produced an emulsion precipitate. This was filtered, and the residue was washed several times with acetone and methanol and then dried under reduced pressure to obtain a white powdery urea compound. This urea compound did not dissolve in DMF, dimethyl sulfoxide (DMSO), methanol, or chloroform.
〔ウレア化合物の分解〕
実施例１～１２、比較例１
　マグネットスターラーを入れた容量：２００ｍｌのステンレス製オートクレーブに、前記ウレア化合物０．５ｇ及び所定量の水（比較例１は不使用）を仕込み、容器内を空気を二酸化炭素で置換した。その後、オートクレーブに液化炭酸ガスを仕込み、バンドヒーターを取り付けて１時間加熱し、所定の内圧及び温度に達したところで、所定の時間撹拌した。その後、氷浴にオートクレーブを浸けて、すばやく冷却した後、常圧に戻し、反応混合物をメタノールで濾過して、メタノールへの可溶物と不溶物に分けて回収した。実施例の結果（Ｒｕｎ１：実施例１、…Ｒｕｎ１２：実施例１２）を表１に示す。不溶物（濾物）をＦＴ－ＩＲ測定したところ（図１）、分解前のウレア化合物のチャートと大きな差は見られなかった。また、可溶物を 1Ｈ－ＮＭＲ測定したところ（図２）、当該物質は４，４′－ジフェニルメタンジアミンと同定できた。 [Decomposition of urea compounds]
Examples 1 to 12, Comparative Example 1
Capacity with magnet stirrer: A 200 ml stainless steel autoclave was charged with 0.5 g of the urea compound and a predetermined amount of water (not used in Comparative Example 1), and the air in the container was replaced with carbon dioxide. Thereafter, liquefied carbon dioxide gas was charged into the autoclave, a band heater was attached and heated for 1 hour, and when a predetermined internal pressure and temperature were reached, the mixture was stirred for a predetermined time. Thereafter, the autoclave was immersed in an ice bath and quickly cooled, and then returned to normal pressure. The reaction mixture was filtered with methanol, and separated into a soluble substance and an insoluble substance in methanol. The results of the examples (Run 1: Example 1,... Run 12: Example 12) are shown in Table 1. When an insoluble matter (filtered material) was measured by FT-IR (FIG. 1), no significant difference was found from the urea compound chart before decomposition. Further, 1 H-NMR measurement of the soluble material (FIG. 2) revealed that the substance was identified as 4,4′-diphenylmethanediamine.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
ＦＴ－ＩＲ測定条件
機器　　：ＦＴＳ３０００型ＦＴ－ＩＲ測定装置（Ｂｉｏ－Ｒａｄ社製）
測定法　：ＫＢｒ法
検出器　：ＭＣＴ
測定範囲：４００～４０００ｃｍ-1
感度　　：２
分解能　：４ｃｍ-1
積算回数：３２回
1Ｈ－ＮＭＲ測定条件
　溶媒　　：ＣＤＣｌ3
測定装置：超伝導多核種磁気共鳴装置ＪＮＭ－ＧＣ４００（日本電子社製）
　積算回数：８回 FT-IR measurement condition equipment: FTS3000 type FT-IR measurement device (manufactured by Bio-Rad)
Measurement method: KBr method detector: MCT
Measurement range: 400 to 4000 cm -1
Sensitivity: 2
Resolution: 4cm -1
Integration count: 32 times
1 H-NMR measurement conditions Solvent: CDCl 3
Measuring apparatus: Superconducting multi-nuclide magnetic resonance apparatus JNM-GC400 (manufactured by JEOL Ltd.)
Integration count: 8 times
　表１に示されている温度と圧力は、水の臨界条件（３７４℃、２２．１ＭＰａ）に達していないので、水は超臨界状態にはなっていないと判断できる。実施例１～１２の全てでウレア化合物の加水分解が確認できた。しかし比較例では、ウレア化合物の分解はされていない結果になった。 Since the temperature and pressure shown in Table 1 have not reached the critical condition of water (374 ° C., 22.1 MPa), it can be determined that the water is not in a supercritical state. In all of Examples 1 to 12, hydrolysis of the urea compound was confirmed. However, in the comparative example, the urea compound was not decomposed.
　実施例１～４について、縦軸に分解率、横軸に水添加量としたグラフを図３に示す。図３から、実施例３が最良（分解率１００％）となった。これは、水の量が少ない場合はウレア化合物の水への拡散レベルが低く、水が多いとウレア化合物の二酸化炭素への拡散レベルが低いと考えられる。この結果から、水と反応容器の好適容積比は、水／反応容器＝１０／１００～３０／１００、最適容積比は水／反応容器＝１５／１００～２５／１００であると言える。 For Examples 1 to 4, a graph with the vertical axis representing the decomposition rate and the horizontal axis representing the amount of water added is shown in FIG. From FIG. 3, Example 3 was the best (decomposition rate 100%). This is considered that the diffusion level of the urea compound into water is low when the amount of water is small, and the diffusion level of the urea compound into carbon dioxide is low when the amount of water is large. From this result, it can be said that the preferred volume ratio of water to the reaction vessel is water / reaction vessel = 10/100 to 30/100, and the optimum volume ratio is water / reaction vessel = 15/100 to 25/100.
　実施例５～９について、縦軸に分解率、横軸に圧力としたグラフを図４に示す。図４から、実施例６～８が最良（分解率１００％）となった。温度が一定のもとでは、二酸化炭素の圧力が大きいほど二酸化炭素の密度は高くなる。低圧では二酸化炭素の拡散レベルが低く、高圧では水の拡散レベルが低いと考えられる。この結果から、内部圧力の最適範囲は、５～１０ＭＰａであることが分かった。 For Examples 5 to 9, a graph with the vertical axis representing the decomposition rate and the horizontal axis representing the pressure is shown in FIG. From FIG. 4, Examples 6 to 8 were the best (decomposition rate 100%). Under a constant temperature, the density of carbon dioxide increases as the pressure of carbon dioxide increases. It is thought that the diffusion level of carbon dioxide is low at low pressure, and the diffusion level of water is low at high pressure. From this result, it was found that the optimum range of internal pressure was 5 to 10 MPa.
実施例１における、分解前のウレア化合物及び分解後の濾物のＦＴ－ＩＲチャートである。2 is an FT-IR chart of a urea compound before decomposition and a filtrate after decomposition in Example 1. メタノール可溶物の1Ｈ－ＮＭＲチャートである。 1 is a 1 H-NMR chart of methanol-soluble matter. 圧力一定下、水添加量を変化させたときのウレア化合物の分解結果である。It is a decomposition | disassembly result of a urea compound when changing the amount of water addition under fixed pressure. 温度一定下、圧力を変化させたときのウレア化合物の分解結果である。It is a decomposition | disassembly result of a urea compound when a pressure is changed under constant temperature.
符号の説明Explanation of symbols
１：分解前のウレア化合物のＦＴ－ＩＲチャートである。
２：分解後の濾物のＦＴ－ＩＲチャートである。 1: FT-IR chart of urea compound before decomposition.
2: FT-IR chart of the filtrate after decomposition.

Claims (4)

  1. 　ウレア化合物を超臨界状態又は亜臨界状態の二酸化炭素中、液体または気体状態の水を用いて加水分解して、対応するアミンを回収することを特徴とする、ウレア化合物の分解処理方法。 A method for decomposing a urea compound, wherein the urea compound is hydrolyzed in carbon dioxide in a supercritical state or subcritical state using water in a liquid or gaseous state to recover the corresponding amine.
  2. 　加水分解時の圧力が５～１０ＭＰａであることを特徴とする、請求項１記載のウレア化合物の分解処理方法。 The method for decomposing a urea compound according to claim 1, wherein the pressure during hydrolysis is 5 to 10 MPa.
  3. 　水と反応容器との容積比が、水／反応容器＝１０／１００～３０／１００であることを特徴とする、請求項１又は２記載のウレア化合物の分解処理方法。 3. The method for decomposing a urea compound according to claim 1, wherein the volume ratio of water to the reaction vessel is water / reaction vessel = 10/100 to 30/100.
  4. 　回収されるアミンが、ジフェニルメタンジアミンであることを特徴とする、請求項１から３のいずれか１項に記載のウレア化合物の分解処理方法。 The method for decomposing a urea compound according to any one of claims 1 to 3, wherein the amine to be recovered is diphenylmethanediamine.
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