JP5865107B2 - Cyclic carbonate synthesis catalyst and cyclic carbonate synthesis method - Google Patents

Description

  The present invention relates to a catalyst for synthesizing a cyclic carbonate compound or a cyclic thiocarbonate (sometimes collectively referred to as a cyclic carbonate compound) and a method for synthesizing a cyclic carbonate using the catalyst.

  Carbon dioxide (CO2) is contained in exhaust gas from combustion processes and reaction processes in factories and the like. Carbon dioxide is known to be a greenhouse gas that causes global warming due to the greenhouse effect. In order to realize a sustainable society with a low environmental burden or the chemical industry, it is desired to separate and recover carbon dioxide from exhaust gas, and to reuse it.

  Therefore, a method for separating and recovering carbon dioxide from exhaust gas has been studied, while the use of carbon dioxide as a raw material for synthesizing other valuable materials by chemical reaction has been studied. As such a chemical reaction, as described in Patent Document 1, there is a reaction in which an epoxy compound and carbon dioxide are reacted in the presence of a specific catalyst. The product described in Chemical Formula 1 is a cyclic carbonate (4- (unsubstituted) -1,3-dioxolan-2-one) has a strong polarity and a high boiling point. It is used in semiconductor manufacturing processes and lithography processes.

JP-T-2002-513787

  However, such a reaction between an epoxy compound and carbon dioxide requires high-purity carbon dioxide, or requires a reaction under high temperature and high pressure. There were huge problems. Therefore, combustion exhaust gas generated from a combustion process or reaction process in a factory or the like cannot be applied as it is as a reaction raw material with an epoxy compound, and use of atmospheric pressure carbon dioxide or combustion exhaust gas has not been achieved. In addition, when trying to apply combustion exhaust gas as a synthetic raw material, it requires a separate carbon dioxide purification process, especially when high pressure treatment is desired, and is energy consuming and not economical, making continuous treatment difficult. There were various problems, such as becoming, and it was not practical.

  Therefore, in view of the above situation, an object of the present invention is to provide a technique that makes it possible to use carbon dioxide in exhaust gas efficiently for synthesis of a cyclic carbonate compound or cyclic thiocarbonate under normal pressure. .

  As a result of intensive studies, the present inventors have found that an organic ionic compound having a terminal hydroxyl group is a catalyst for producing a cyclic carbonate compound or a cyclic thiocarbonate from the reaction of an epoxy compound or an episulfide (thiirane) compound with carbon dioxide. It has been found that it functions effectively and is useful for recovering carbon dioxide gas in exhaust gas, and has completed the present invention.

Ie, characterizing feature of the cyclic carbonate synthesis catalyst to produce a cyclic carbonate compound from an epoxy compound and carbon dioxide of the present invention is an organic ionic compounds with a terminal hydroxy group, said organic ionic compound Is at least one selected from N- (2-hydroxyethyl) pyridinium salt, N, N, N, N-tetra (2-hydroxyethyl) ammonium salt, N-methyl-N- (2-hydroxyethyl) pyrrolidinium salt It lies in you containing as an active ingredient a salt containing cations.

That is, in this invention, examples of the organic ionic compound, among the compounds shown in Chemical Formula 2 (B), (D) , Ru with (E).

Ie, the ionic compound B of the organic, D, in the case of using E, the synthesis reactions shown in Chemical Formula 1, utilizing a low concentration of carbon dioxide contained in the atmospheric gas as a synthetic raw material The carbonation reaction proceeds satisfactorily at a reaction temperature of about room temperature, and the corresponding cyclic carbonate product is obtained. As a result, under the reaction conditions close to the environmental conditions in which exhaust gas is generated, a chemical reaction using an epoxy compound and carbon dioxide as raw materials can be performed, and valuable materials can be produced while suppressing the emission of greenhouse gases. It became clear that The above reaction proceeds sufficiently at a low concentration of carbon dioxide due to the high activity of the catalyst, and proceeds at a low temperature of about room temperature. Therefore, the reaction can be proceeded simply and economically.

  The cyclic carbonate obtained here is used, for example, as a non-aqueous electrolyte for a lithium battery and as a solvent in a semiconductor manufacturing process or a lithography process.

These B, D, and E compounds are organic ionic compounds that are known to have particularly high heat stability and little volatilization, and exhibit extremely high stability and catalytic activity under the above reaction conditions. It is thought that it shows. Therefore, it is considered that high catalytic activity can be exhibited similarly by using an organic ionic compound as a catalyst.
In addition, an inorganic ionic compound (KBr, KI, etc.) may be used as a catalyst for synthesizing the cyclic carbonate shown in Chemical Formula 1, but with such an inorganic ionic compound, the solubility in an organic solvent is low. A cyclic carbonate cannot be obtained successfully. However, in the present invention, the solubility in organic solvents as compared with an inorganic ionic compound is using a significantly higher organic ionic compounds can be synthesized epoxy compound or found that the cyclic carbonates corresponding.

The organic ionic compounds B, D and E are characterized by having a terminal hydroxyl group at the same time as an ammonium cation species. Thereby, the carbonic acid half ester in the catalytic reaction is stabilized, and the cyclic carbonate can be synthesized efficiently. In Patent Document 1, since an ammonium salt having no terminal hydroxyl group is used, the activation of the raw material epoxy compound does not occur in the reaction mechanism shown in Chemical Formula 3, so that the cyclic carbonate reaction proceeds slowly. In addition, since the carbonic acid half ester intermediate produced in Step 3 is usually unstable, it returns to carbon dioxide and the ring-opened epoxy anion, making it difficult to produce the desired cyclic carbonate, thus moving the equilibrium toward the cyclic carbonate. Therefore, it is necessary to increase the carbon dioxide concentration.

  On the other hand, in the present invention, since an ammonium salt having a terminal hydroxyl group is used as a catalyst, the epoxy compound is activated by hydrogen bonding between the starting epoxy compound and the hydroxyl group at the end of the ammonium salt to form a cyclic carbonate. The reaction proceeds efficiently. Further, since the carbonic acid half ester intermediate produced by Step 3 shown in Chemical Formula 3 is stabilized by the terminal hydroxyl group of the ammonium salt, Step 4 efficiently proceeds to produce the desired cyclic carbonate, and the ammonium salt catalyst is regenerated. The Thus, by using an organic ionic compound having a terminal hydroxyl group as a catalyst, the partial pressure of carbon dioxide can be reduced, and even if carbon dioxide at normal pressure or carbon dioxide with low purity is used, cyclic carbonation reaction Progresses well.

In addition, as a catalyst for cyclic carbonate synthesis, an ammonium ionic compound may be contained as an active ingredient, and other auxiliary ingredients may be contained. In this application, if the specific component of a catalyst is contained in a ratio sufficient to assume a catalyst function, it shall be included as an active ingredient. For example, the B, D, when using the compounds of the E, for the epoxy compounds, preferable to function to a high activity as a catalyst if used about 0.1 to 10%.

Also, characteristic feature of the cyclic carbonate synthesis method of the present invention, in the presence of the cyclic carbonate synthesis catalyst, Ru near the point of reacting a gas containing carbon dioxide to the epoxy compound.

Also, gas containing pre SL carbon dioxide, is preferably a gas containing 3-10% of carbon dioxide.

Also, the epoxy compound is not particularly limited and exemplified for explanation, of 4 (a) can be used compounds of mule having ~ a glycidyl group (d), the these compounds It is confirmed that the corresponding cyclic carbonate can be obtained by performing the cyclic carbonate synthesis method of the present application using

In the presence of the upper Symbol cyclic carbonate synthesis catalyst, for example, when carbon dioxide gas containing such as the exhaust gas is reacted to an epoxy compound, cyclic Kabone it wants to correspond to said epoxy compound is produced. At this time, the carbon dioxide gas in the exhaust gas reacts sufficiently at a low concentration of about 3 to 10%, and can sufficiently maintain the reaction with the amount of heat possessed by the exhaust gas. It can be read that the reaction can be maintained. Therefore, it does not require a large reactor that requires high temperature and high pressure, can be easily applied as a facility associated with a combustion device that generates exhaust gas, and can produce a cyclic carbonate as a valuable material with a small capital investment, It can contribute to the reduction of greenhouse gases.

In the above reaction, when the epoxy compound is styrene oxide, styrene carbonate is obtained as a cyclic carbonate, and is used, for example, as an electrolyte of a lithium battery.
In addition, ethylene carbonate produced from ethylene oxide is used as a solvent for a capacitor or a battery electrolyte, and is also used as a solvent for a polymer compound and a reaction solvent for various chemical reactions.
Propylene carbonate produced from propylene oxide is also used in various applications such as an electrolyte for lithium batteries, a solvent, and a soil modifier.
The cyclic carbonate obtained in the present invention can be used as a flame retardant, and the cyclic carbonate compound itself is a flame retardant that does not ignite in the flame contact test. In another aspect, a hydrophilic polycarbonate or an oligomer thereof was obtained from a compound having a cyclic carbonate and a phenolic hydroxyl group.

Also, in the above configuration, the reaction temperature for reacting the gas containing carbon dioxide to the epoxy compound, the normal temperature ° C. or higher 200 ° C. or less, it is preferable to set the reaction pressure to atmospheric pressure ～760KPaG.

Ie, according to the cyclic carbonate synthesis catalyst, a wide range of reaction conditions can be carried out cyclic carbonate synthesis, for example, high temperature and high pressure as hydrogen gas in the hydrogen production apparatus for producing hydrogen gas (e.g. 200 ° C., about 760KPaG) Regardless of whether carbon dioxide containing exhaust gas or normal temperature and pressure carbon dioxide containing exhaust gas is applied, carbon dioxide containing exhaust gas in a wide concentration range from low concentration to high concentration (100%) is continuously produced in a mild reaction state. It can be used for cyclic carbonate synthesis.

Before SL reaction temperature is preferably at 50 ° C. or higher.

Na us, the reaction is to proceed be about room temperature has been confirmed, preferably not less than 50 ° C. The reaction temperature. In such a form, not only high-temperature exhaust heat such as combustion exhaust gas, but also wastewater from factories, sludge incineration, hot water from condensers for power generation and waste incineration, etc. can be used, so a lot of exhaust heat is extracted. Even when the cyclic carbonate synthesis process is incorporated into various industrial plants that cannot be performed, the reaction conditions can be set efficiently.

Before SL cyclic carbonate synthesis catalyst, it is preferred that at some with the reaction solvent 10g per 0.05mmol more.

Even if catalytic amount is relatively small, the reaction even at room temperature while slowly found to proceed, it is possible to realize a suitable reaction efficiency by adjusting the reaction time appropriately according to the carbon dioxide concentration, reaction temperature conditions . In particular, if it is 0.05 mmol or more per 10 g of the reaction solvent, it is clear that a rapid reaction proceeds at 80 ° C., and it can be said that the catalyst amount is suitable for setting suitable reaction conditions. Even if the amount of catalyst is large, there is no particular problem (for example, when the catalyst itself serves as a solvent, the content can be considered as ∞ g / solvent 10 g), and it can be used regardless of the upper limit.

Also, characteristic feature of the carbon dioxide fixation process of the present invention is a carbon dioxide containing exhaust gas is reacted with the epoxy compound to the point to be converted to cyclic carbonate.

Ie, because immobilizing carbon dioxide by utilizing the reaction for synthesizing the valuable substance by cyclic carbonate synthesis reactions, while achieving the reduction of greenhouse gases, it is possible to generate added value. Here, when applying the carbon dioxide immobilization method of the present invention to various carbon dioxide-containing exhaust gas generation sites, since the above reaction can maintain a gentle reaction under a wide range of conditions, the introduction environment is not easily restricted, In addition, there is an advantage that the introduction cost can be estimated low by the production of valuable materials.

Also, characteristic feature of the carbon dioxide immobilization device, the reaction solution comprising the cyclic carbonate synthesis catalyst dissolved together with the epoxy compound, a point having a reaction vessel and reacted with the supply of carbon dioxide-containing flue gas It is in.

Ie, the cyclic carbonate synthesis catalyst to the reaction solution obtained by dissolving both the said epoxy compound, by a simple device configuration of merely supplying carbon dioxide-containing flue gas, valuable materials while immobilization of carbon dioxide Can be produced.

Na us, in the above configuration, the carbon dioxide-containing flue gas is, the fuel gas may be a hydrogen production exhaust gas in the hydrogen production apparatus for producing hydrogen gas by reforming.

And the hydrogen production apparatus for producing hydrogen gas For example, the high-temperature high-pressure carbon dioxide containing exhaust gas as hydrogen gas, but the carbon dioxide containing exhaust gas of the normal temperature and pressure are generated, also the carbon dioxide fixation to any of these The production method can be applied, and valuable materials can be continuously produced in a mild reaction state.

  Therefore, it has become possible to efficiently produce cyclic carbonates while reducing greenhouse gases.

It is a flowchart of a hydrogen production apparatus It is the schematic of carbon dioxide fixation

The present invention will be described below according to specific embodiments. In addition, the following embodiment is illustrated in order to clarify this invention, Comprising: This invention is not limited to the following embodiment. In the following embodiments, descriptions relating to episulfide compounds are described for reference.

In the present invention, a cyclic carbonate compound is produced from an epoxy compound and carbon dioxide using a cyclic carbonate synthesis catalyst comprising an organic ionic compound.
For reference, a cyclic thiocarbonate can also be produced from an episulfide compound and carbon dioxide using a cyclic carbonate synthesis catalyst comprising an organic ionic compound. Below, the case where a cyclic thiocarbonate is used is described together with the case where an episulfide compound is used.

Examples of the organic ionic compound include A) 1-methyl-3- (2-hydroxyethyl) imidazolium salt, (B) N- (2-hydroxyethyl) pyridinium salt, (C) N, N, N- Triethyl-N- (2-hydroxyethyl) ammonium salt, (D) N, N, N, N-tetra (2-hydroxyethyl) ammonium salt, (E) N-methyl-N- (2-hydroxyethyl) pyrrolidinium Those containing a salt containing at least one cation selected from salts (see Chemical Formula 2) as an active ingredient are preferably used. As the counter ion, various anions such as halide ion, trifluoroacetate ion, bisfluorosulfonium imide ion can be applied.
In the present invention, among the above salts, the organic ionic compound is N- (2-hydroxyethyl) pyridinium salt, N, N, N, N-tetra (2-hydroxyethyl) ammonium salt, N-methyl. The same applies to the case where a salt containing at least one cation selected from —N- (2-hydroxyethyl) pyrrolidinium salt is used.

  In the presence of the cyclic carbonate synthesis catalyst, the combustion exhaust gas is reacted with an epoxy compound or an episulfide compound. This reaction can be performed by bringing the exhaust gas into contact with a liquid phase obtained by dissolving an epoxy compound or an episulfide compound together with the catalyst for synthesizing the cyclic carbonate. In order to increase the gas-liquid contact efficiency, it is effective to bubbling exhaust gas against the liquid phase or to allow the gas phase to circulate counter to the liquid phase that is circulated down to the contact material. Can also be carried out by stirring and mixing the liquid phase retained in the exhaust gas.

  As said exhaust gas, what contains 3-10% of carbon dioxide as a normal combustion exhaust gas is used suitably, and it can produce | generate a cyclic carbonate with high efficiency.

  In addition, such combustion exhaust gas usually reaches about 100 ° C. to 1000 ° C. and falls in the gas pipeline, but the reaction temperature is maintained in a suitable temperature range of about 100 ° C. by the heat of the exhaust gas. be able to.

  As the epoxy compound and episulfide compound, any compound having a glycidyl group or an epithio group can be used as shown in Chemical Formula 4, and these compounds exhibit similar reactivity to carbon dioxide, It is known that the above reaction converts it into a valuable material with high utility value.

Embodiment 1
0.50 mmol of the compound (C) in Chemical Formula 2 is added as an ammonium-based ionic compound (catalyst) to the flask, and 10.0 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. Further, 1.21 g (10 mmol) of styrene oxide (manufactured by Nacalai Tesque) is added to this solution.
The reaction vessel was attached to a reflux pipe, and introduced into the reaction solution for 20 minutes while flowing simulated exhaust gas having a carbon dioxide concentration of 5% (the remainder was Ar), and was bubbled at room temperature (20 ° C.) and normal pressure (101.3 kPa). . Next, the reaction bath was sealed with a ball plug, and then heated and stirred at 100 ° C. for 24 hours while flowing the simulated exhaust gas in a three-way cock at the top of the reflux tube.

The obtained reaction solution was analyzed by GC, and the conversion and selectivity in the reaction of Chemical Formula 1 were determined.
In addition, when calculating | requiring a conversion rate and a selectivity, after that, a reaction solution was put into 30 mL distilled water, and it extracted by ethyl acetate 30 mL x 1 time and 20 mL x 2 times. The extract was washed with distilled water 20 mL × 8 times, and the separated ethyl acetate solution was dried over anhydrous sodium sulfate. Anhydrous sodium sulfate was filtered off and ethyl acetate was distilled off to obtain a weighed product. This product was analyzed by gas chromatography. From the peak area, the area percentage of the contained compound (raw material styrene oxide and product styrene carbonate and by-product) was determined, and the conversion and selectivity were calculated.

Conversion rate: Conversion rate = 100− (area percentage of raw material styrene oxide)
As sought.
Selectivity is
Selectivity = (area percentage of styrene carbonate produced) / (conversion rate) × 100
As sought.

As a result, 95% of the raw material styrene oxide was converted to styrene carbonate from the peak area of styrene carbonate in the reaction solution (conversion rate 95%), and 5% of residual styrene oxide was detected in the reaction solution. No product was detected (selectivity 100%).
The 1H NMR (CDCl3) spectrum of the resulting styrene carbonate was 4.34 (dd, 1H), 4.80 (dd, 1H), 5.68 (m, 1H), 7.2-7.4 (m , 5H).

[Comparative Example 1]
In place of ammonium-based ionic compound (catalyst), sodium chloride was used, and the conversion rate and selectivity were determined in the same manner as in Embodiment 1. As a result, the conversion rate was 57% (selectivity 100%). It was found that the reaction efficiency was improved by using the compound (C) in Chemical Formula 2 as (catalyst).

[Embodiment 2]
0.10 mmol of each compound in Chemical Formula 2 is added to the flask as an organic ionic compound (catalyst), and 10.0 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. In addition, 1.21 g of styrene oxide (10 mmol) is added to this solution.
The reaction vessel was attached to a reflux tube, introduced into the reaction solution for 20 minutes while flowing a gas having a carbon dioxide concentration of 100%, and bubbled at room temperature. Next, after sealing the reaction bath with a ball stopper, the mixture was heated and stirred at 100 ° C. for 17 hours while flowing a gas having a carbon dioxide concentration of 100% through a three-way cock at the top of the reflux tube.

  The obtained reaction solution was analyzed by GC, and the conversion and selectivity in the reaction of Chemical Formula 1 were determined. In addition, for the ionic compounds, the counter ions were also variously changed and the catalytic activities were compared. The results are shown in Table 1. In Table 1, each row item indicates a cation species of an organic ionic compound, and each column item indicates an anion species.

  From Table 1, it was found that according to each organic ionic compound, styrene carbonate can be obtained from styrene oxide with high selectivity. Moreover, since this reaction can be performed continuously, it is considered that even if the conversion rate is low, it can contribute to the fixation of carbon dioxide with high efficiency.

[Embodiment 3]
Triglycidyl cyanurate (Nissan Chemical Co., Ltd.) 50.15 g, (169 mmol) is added to the flask, and N-methyl-2-pyrrolidone (NMP) (solvent) 508 g is added. Further, 8.49 mmol of the compound (C) in Chemical Formula 2 is added as an ammonium-based ionic compound (catalyst) to this solution. The reaction vessel was attached to a reflux tube, and stirred with heating at 100 ° C. for 24 hours while bubbling a gas having a carbon dioxide concentration of 100% into the reaction solution at normal pressure. After completion of the reaction, the white solid obtained by adding the reaction solution to 2 L of distilled water was filtered with a glass filter and washed with acetone to obtain 63.68 g of cyclic carbonate shown in Chemical formula 5 with a yield of 88%. It was.
The 1H NMR (CDCl ₃ ) spectrum of the obtained cyclic carbonate is 4.06 (dd, 3H), 4.19 (dd, 3H), 4.32 (dd, 3H), 4.56 (dd, 3H). , 4.94 (m, 3H).
Moreover, C = O stretching vibration (IR) of the obtained cyclic carbonate was 1786 cm-1.

[Embodiment 4]
A flask is charged with 50.75 g (125 mmol) of sorbitol polyglycidyl ether (manufactured by Nagase Chemtech), and 402 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. Further, 10.3 mmol of the compound (C) in Chemical Formula 2 is added as an ammonium-based ionic compound (catalyst) to this solution. The reaction vessel was attached to a reflux tube, and stirred with heating at 100 ° C. for 31 hours while bubbling a gas having a carbon dioxide concentration of 100% into the reaction solution at normal pressure. After completion of the reaction, the white suspension obtained by adding the reaction solution to 1 L of distilled water was extracted with 400 mL of ethyl acetate four times. The obtained ethyl acetate solution was washed with water, dried over anhydrous magnesium sulfate, and the ethyl acetate was distilled off to obtain 50.82 g of a yellow cyclic carbonate oily product represented by Chemical Formula 6 in a yield of 70%. It was.
The 1H NMR (CDCl3) spectrum of the obtained cyclic carbonate was 3.3-4.2 (m), 4.2-4.6 (m), and 4.7-5.0 (m).
Moreover, C = O stretching vibration (IR) of the obtained cyclic carbonate was 1786 cm-1.

[Embodiment 5]
52.09 g of Epicoat 828 (manufactured by Japan Epoxy Resin Co., Ltd.) (138 mmol) is placed in the flask, and 208 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. Moreover, 7.03 mmol of (C) compound in Chemical formula 2 is added to this liquid as an ammonium type ionic compound (catalyst). The reaction vessel was attached to a reflux tube, and stirred with heating at 100 ° C. for 21 hours while bubbling a gas having a carbon dioxide concentration of 100% into the reaction solution at normal pressure. After completion of the reaction, the white solid obtained by adding the reaction solution to 2 L of distilled water was filtered with a glass filter and washed with acetone to obtain 63.68 g of cyclic carbonate shown in Chemical formula 7 in a yield of 88%. It was.
1H NMR (DMSO-d6) spectrum of the obtained cyclic carbonate was 1.57 (s, 6H) 4.14 (dd, 2H), 4.23 (dd, 2H), 4.37 (dd, 2H). 4.61 (dd, 2H), 5.11 (m, 2H), 6.84 (d, 4H), 7.11 (d, 4H).
Moreover, C = O stretching vibration (IR) of the obtained cyclic carbonate was 1786 cm-1.

[Embodiment 6]
0.50 mmol of the compound (C) in Chemical Formula 2 is added as an ammonium-based ionic compound (catalyst) to the flask, and 10.0 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. In addition, 29.71 g of the above compound (B) (10- (2 ′, 5′-diglycidyl ether phenyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) was added to this liquid. 68.1 mmol) is added.
The reaction vessel was attached to a reflux tube, introduced into the reaction solution for 20 minutes while flowing carbon dioxide, and bubbled at room temperature and normal pressure. Next, the reaction bath was sealed with a ball plug, and then heated and stirred at 80 ° C. for 24 hours while flowing the simulated exhaust gas through a three-way cock at the top of the reflux tube.

After completion of the reaction, a white solid obtained by adding the reaction solution to 2 L of distilled water was filtered through a glass filter, whereby 32.20 g of a phosphinic acid ester compound having a cyclic carbonate structure as a product was obtained in a yield of 99%. Obtained.
1HNMR (CDCl3) spectrum of the obtained phosphinic acid ester compound having a cyclic carbonate structure is 8.3-6.2, m, (aromatic proton), 4.94, bs (proton of cyclic carbonate structure), 4.48, m, (cyclic carbonate structure proton), 4.2-2.8, m, (cyclic carbonate structure proton and oxymethylene proton), 1.82, s, (hydroxyl group proton) there were.
Moreover, the C = O stretching vibration (IR) of the obtained phosphinic acid ester compound having a cyclic carbonate structure was 1793 cm-1.
From these data, the obtained compound was 10- [4-di (2-oxo-1,3-dioxolylmethyloxy) phenyl] -9,10-dihydro-9-oxa-10-phosphaphenanthrene. It was confirmed that it was -10-carbonate.

[Embodiment 7]
1.50 g (10 mmol) of 1,2-epoxy-3-phenoxypropane is added to the flask, and 20 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. In addition, 0.20 mmol of the compound (C) in Chemical Formula 2 is added as an ammonium-based ionic compound (catalyst) to this solution. The reaction vessel was attached to a reflux tube, and stirred with heating at various temperatures for various times while bubbling a gas having a carbon dioxide concentration of 100% into the reaction solution at normal pressure.
The reaction solutions obtained at various temperatures and times were analyzed by GC, and the yield of the cyclic carbonate compound in the reaction of Chemical Formula 1 (conversion rate × selectivity) was determined.

  As a result, a cyclic carbonate compound was obtained in a yield shown in Table 2 from the GC peak area.

[Embodiment 8]
1.50 g (10 mmol) of 1,2-epoxy-3-phenoxypropane is added to the flask, and 20 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. In addition, 0.20 mmol of the compound (C) in Chemical Formula 2 is added as an ammonium-based ionic compound (catalyst) to this solution. The reaction vessel was attached to a reflux tube, and stirred with heating to 100 ° C. for 22 hours while bubbling a gas having a carbon dioxide concentration of 5% into the reaction solution at normal pressure.
The reaction solutions obtained at various times were analyzed by GC, and the yield of the cyclic carbonate compound in the reaction of Chemical Formula 1 was determined.

  As a result, a cyclic carbonate compound was obtained in a yield shown in Table 3 from the GC peak area. The result of the reaction rate almost the same as 100 ° C. in Embodiment 7 is obtained, that is, it can be expected that the reaction proceeds at a rate equivalent to that of pure carbon dioxide gas even with a carbon dioxide concentration gas contained in the combustion exhaust gas.

[Embodiment 9]
1.50 g (10 mmol) of 1,2-epoxy-3-phenoxypropane is added to the flask, and 20 g of N-methyl-2-pyrrolidone (NMP) (solvent) is added. Further, 1.00 mmol of the compound (C) in Chemical Formula 2 is added to this solution as an ammonium-based ionic compound (catalyst). The reaction vessel was attached to a reflux tube, and stirred with heating at 60 ° C. to 22 hr while bubbling a gas having a carbon dioxide concentration of 100% into the reaction solution at normal pressure.
The reaction solutions obtained at various times were analyzed by GC, and the yield of the cyclic carbonate compound in the reaction of Chemical Formula 1 was determined.

  As a result, a cyclic carbonate compound was obtained in a yield shown in Table 4 from the peak area of GC. The reaction rate is faster than 80 ° C. in Embodiment 7, and the practical range can be expected to expand to a lower temperature range by increasing the amount of catalyst.

[Summary]
The above embodiments are summarized in Table 5. From Table 5, it is considered that the reaction rate of cyclic carbonate synthesis varies depending on the reaction temperature and the amount of catalyst. On the other hand, it is considered that the kind of raw material epoxy compound and the carbon dioxide concentration do not significantly affect the reaction rate.

  That is, when the catalyst shown in Chemical Formula 2 is used as the catalyst, the carbonation reaction proceeds rapidly (more than the extent that a yield of 50% or more can be expected in 24 hours) at about 100 ° C. (Embodiments 2-5, and 7). . Even if the reaction temperature is low, the reaction proceeds sufficiently if a sufficient amount of catalyst is secured. (Embodiments 6 and 9 with respect to Embodiments 2 and 7)

When the amount of catalyst is large (about 0.5 mmol with respect to 10 g of NMP) and the reaction temperature is relatively high (about 100 ° C.), the reaction proceeds rapidly even if the carbon dioxide concentration is low (even about 5%). (Embodiment 1) On the other hand, even if the amount of catalyst is small, if the reaction temperature is sufficiently high, the reaction proceeds rapidly even if the carbon dioxide concentration is low (even about 5%). (Embodiment 8)
Therefore, it can be seen that if the reaction temperature is high, even a low concentration of carbon dioxide can be efficiently immobilized by use in the synthesis of cyclic carbonate.

  According to Table 5, regardless of the carbon dioxide concentration and the type of epoxy compound, if the reaction temperature is 80 ° C. or more, a rapid reaction occurs by using a catalyst amount of 0.10 mmol or more with respect to 10 g of the solvent (embodiment) 1-8) It can be considered that a sufficient reaction rate can be obtained even if the amount of the catalyst is further reduced to about 0.05 mmol. In addition, when prescribing the amount of catalyst, for example, the content when the catalyst itself serves as a solvent can be considered to be ∞ g / 10 g of solvent, and can be used regardless of the upper limit. Also, with respect to the carbon dioxide concentration, since a sufficiently high reaction rate is obtained with the carbon dioxide concentration (about 3 to 10%) contained in the combustion exhaust gas, the carbon dioxide concentration is lower (for example, about 0.1%). Even if it exists, it is thought that it can react reliably.

  Furthermore, when the amount of the catalyst is large (about 0.5 mmol with respect to 10 g of NMP), it can be read that the reaction proceeds quickly even when the temperature is low, and the reaction temperature is preferably 50 ° C. or higher (Embodiment 9). In such a form, not only high-temperature exhaust heat such as combustion exhaust gas, but also wastewater from factories, sludge incineration, hot water from condensers for power generation and waste incineration, etc. can be used, so a lot of exhaust heat is extracted. It will be possible to incorporate a cyclic carbonate synthesis process into an industrial plant that cannot.

  As shown in Embodiment 7, even when the amount of catalyst is relatively small, it can be seen that the reaction proceeds slowly even at room temperature, and it is preferable to appropriately adjust the reaction time according to the carbon dioxide concentration and reaction temperature conditions. It can be seen that a high reaction efficiency can be realized.

[Embodiment 10]
An example will be shown in which the cyclic carbonate synthesis method performed in the above embodiment is used to immobilize carbon dioxide in hydrogen production exhaust gas in the hydrogen production apparatus 100 that reforms fuel gas to produce hydrogen gas.

(Hydrogen production equipment)
As shown in FIG. 1, the hydrogen production apparatus 100 used in the present embodiment includes a desulfurizer 1 that desulfurizes natural gas as a fuel gas, and a reformer that reforms the natural gas desulfurized by the desulfurizer 1. 2, comprising a transformer 3 for reforming natural gas and oxidizing the carbon monoxide gas contained in the reformed gas mainly composed of hydrogen and carbon dioxide into carbon dioxide. The hydrogen PSA device 4 for purifying the reformed gas having passed through 3 by a PSA process (pressure fluctuation adsorption process) is provided, and the hydrogen gas obtained from the hydrogen PSA device 4 can be supplied as product hydrogen gas.

  In the hydrogen production apparatus 100, offgas (exhaust gas) from the hydrogen PSA apparatus 4 is temporarily stored in the offgas tank 5 and used as fuel for the heating burner 21 in the reformer 2.

With this configuration,
(A) the reformed gas supplied to the hydrogen PSA device 4, (B) the offgas temporarily stored in the offgas tank 5, and (C) the exhaust gas from the heating burner 21 in the reformer 2, respectively. Carbon dioxide is contained and can be handled as a carbon dioxide-containing exhaust gas in the carbon dioxide fixing device 200. Table 6 shows the properties of each carbon dioxide-containing exhaust gas.

(CO2 immobilizer)
The carbon dioxide immobilization apparatus 200 that performs the carbon dioxide immobilization method using the cyclic carbonate synthesis method of the present invention is provided in at least one of the supply paths (A) to (C) of the carbon dioxide-containing exhaust gas in the hydrogen production apparatus 100. As shown in FIG. 2, the cyclic carbonate synthesis catalyst is dissolved in NMP as a reaction solvent together with styrene oxide as the epoxy compound or episulfide compound (hereinafter referred to as raw material). A reaction tank 6 is provided for supplying and reacting the contained exhaust gas.

  The reaction tank 6 includes a raw material supply unit 61 that supplies the raw material and a catalyst supply unit 62 that supplies the cyclic carbonate synthesis catalyst, and is dissolved in an NMP solvent as a reaction solvent together with the cyclic carbonate synthesis catalyst. And a carbon dioxide-containing gas supply unit 63 for supplying and bubbling carbon dioxide-containing exhaust gas to the reaction solution. In addition, a heat exchanger 64 for maintaining a reaction temperature (here, about 50 ° C. to 80 ° C.) for performing the cyclic carbonate synthesis reaction is provided inside the reaction vessel 60. The reaction vessel 60 is provided in a plurality of stages as necessary, and is adjusted so that the cyclic carbonate synthesis reaction is sufficiently advanced while being sequentially transferred through the transfer path 65. Further, the reaction tank 6 is provided with a gas vent path 66 so that miscellaneous gases and the like by-produced by the synthesis reaction can be periodically discharged. In addition, the carbon dioxide-containing exhaust gas is configured to be repeatedly bubbled into the reaction tank via the resupply path 67 for the purpose of increasing the efficiency of gas-liquid contact.

  The reaction liquid after the completion of the cyclic carbonate synthesis reaction is supplied to the cyclic carbonate extraction tank 7 so as to collect the cyclic carbonate and to recover and reuse the extraction solvent.

  The cyclic carbonate extraction tank 7 includes a reaction liquid supply unit 71 for supplying the reaction liquid, and extraction liquid supply parts 72 and 73 for supplying water and ethyl acetate as extraction solvents. An extract collecting unit 74 (an aqueous layer collecting unit 74a and an organic layer collecting unit 74b) that separates and collects the product is provided. The extract recovered from the extract recovery unit 74 is separately supplied to the distillation purification unit 8 (catalyst recovery unit 81 and carbonate purification unit 82), and the extraction solvent, reaction solvent, and cyclic carbonate synthesis catalyst can be regenerated and supplied again. To. The distillation purification unit 8 is provided with a heat exchange device 9 for heating and distilling the extract.

The heat exchange device 9 includes a heat medium circulation path 92 that circulates the heat medium, a heat medium circulation pump 92 that receives heat supply, and an exhaust heat exchange unit 93, and the exhaust heat heat exchange unit 93 includes the reformer 2. The heat medium is heated by receiving exhaust heat from the heating burner 21 and the like, and the heat medium is circulated through the heat medium circulation path 91 by the heat medium circulation pump 92.
The heat medium is circulated through a heat exchanger 94 that allows water contained in the extract supplied to the catalyst recovery unit 81 to be distilled off as water vapor so that the catalyst can be recovered, and is further supplied to the carbonate purification unit 82. Ethyl acetate contained in the extract is evaporated and distilled, and the carbonate is circulated through a heat exchanger 95 that heats it so that it can be purified. Moreover, the heat medium which heated the distillation refinement | purification part 8 is further circulated to the heat exchanger 64 provided in the said reaction tank 6, and is heat-exchanged in order to maintain reaction temperature. The heat medium that is supplied with heat to each heat exchanger and is cooled is returned to the exhaust heat exchanger 93 by the heat medium circulation pump.

(Immobilization of carbon dioxide)
The carbon dioxide-containing exhaust gas of (A) to (C) in each flow path of the hydrogen production apparatus 100 is completely consumed by the carbon dioxide fixing apparatus 200 configured as described above in the reaction tank 6. And bubbling from the carbon dioxide-containing gas supply unit 63 under the above conditions, ethyl acetate is recovered from the carbonate purification unit 82 and water and the cyclic carbonate are recovered from the catalyst recovery unit 81 for any carbon dioxide-containing exhaust gas. It was found that the catalyst for synthesis and the reaction solvent can be recovered and recycled, and the carbon dioxide in the carbon dioxide-containing exhaust gas can be fixed and converted into a valuable substance while continuously producing a cyclic carbonate. .

  That is, according to the carbon dioxide immobilization apparatus 200, even about 40% of carbon dioxide containing exhaust gas in a pressurized state of about normal pressure to about 760 kPaG can be fixed under mild conditions and converted into a valuable material. It became so.

  In the carbon dioxide immobilization apparatus 200, NMP, ethyl acetate, water, or the like is used as a reaction solvent or an extraction solvent. However, these are examples that can be suitably used in the carbon dioxide immobilization apparatus. Depending on the type of raw material, the properties of the exhaust gas, etc.

  Further, the carbon dioxide-containing exhaust gas is not limited to the exhaust gas from the hydrogen production apparatus 100, and can be applied to the carbon dioxide-containing exhaust gas discharged from various production apparatuses and the like.

1: Desulfurizer 2: Reformer 21: Heating burner 3: Transformer 4: Hydrogen PSA device 5: Off-gas tank 6: Reaction tank 60: Reaction vessel 61: Raw material supply unit 62: Catalyst supply unit 63: Carbon dioxide contained Gas supply part 64: Heat exchanger 65: Sequential transfer path 66: Degassing path 67: Resupply path 7: Cyclic carbonate extraction tank 71: Reaction liquid supply part 72: Extract liquid supply part 74: Extract liquid recovery part 74a: Water Layer recovery unit 74b: Organic layer recovery unit 8: Distillation purification unit 81: Catalyst recovery unit 82: Carbonate purification unit 9: Heat exchange device 91: Heat medium circulation path 92: Heat medium circulation pump 93: Waste heat exchange unit 94: Heat exchanger 95: Heat exchanger 100: Hydrogen production device 200: Carbon dioxide fixing device

Claims (10)

A cyclic carbonate synthesis catalyst to produce a cyclic carbonate compound from an epoxy compound and carbon dioxide, an organic-based ionic compounds with a terminal hydroxy group, said organic ionic compound, N-(2-hydroxy Effectively a salt containing at least one cation selected from ethyl) pyridinium salt, N, N, N, N-tetra (2-hydroxyethyl) ammonium salt, N-methyl-N- (2-hydroxyethyl) pyrrolidinium salt cyclic carbonate synthesis catalyst containing as components. In the presence of a cyclic carbonate synthesis catalyst according to claim 1, the cyclic carbonate synthesis method of reacting a gas containing carbon dioxide to the epoxy compound. The cyclic carbonate synthesis method according to claim 2 , wherein the gas containing carbon dioxide is a gas containing 3 to 10% carbon dioxide. The epoxy compound is styrene oxide, triglycidyl cyanurate, bisphenol A diglycidyl ether, sorbitol polyglycidyl ether , 10- (2 ′, 5′-diglycidyl ether phenyl) -9,10-dihydro-9-oxa. The method for synthesizing a cyclic carbonate according to claim 2 or 3 , which is at least one selected from -10-phosphaphenanthrene-10-oxide and 1,2-epoxy-3-phenoxypropane. The cyclic carbonate according to any one of claims 2 to 4 , wherein a reaction temperature for reacting a gas containing carbon dioxide with an epoxy compound is from ordinary temperature to 200 ° C, and a reaction pressure is from atmospheric pressure to 760 kPaG. Synthesis method. The cyclic carbonate synthesis method according to claim 5 , wherein the reaction temperature is 50 ° C. or higher. The cyclic carbonate synthesis method according to claim 5 or 6 , wherein the cyclic carbonate synthesis catalyst is 0.05 mmol or more per 10 g of the reaction solvent. In the presence of a cyclic carbonate synthesis catalyst according to claim 1, carbon dioxide immobilization method of converting a carbon dioxide-containing flue gas is reacted with the epoxy compound to the cyclic carbonate. To the reaction mixture a cyclic carbonate synthesis catalyst obtained by dissolving both the said epoxy compound according to claim 1, the carbon dioxide fixing apparatus provided with a reaction vessel and reacted with supplying carbon dioxide containing exhaust gas. The carbon dioxide immobilization apparatus according to claim 9 , wherein the carbon dioxide-containing exhaust gas is a hydrogen production exhaust gas in a hydrogen production apparatus that reforms a fuel gas to produce hydrogen gas.

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