JP2022047222A - Method for producing isocyanic acid - Google Patents
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- JP2022047222A JP2022047222A JP2020153007A JP2020153007A JP2022047222A JP 2022047222 A JP2022047222 A JP 2022047222A JP 2020153007 A JP2020153007 A JP 2020153007A JP 2020153007 A JP2020153007 A JP 2020153007A JP 2022047222 A JP2022047222 A JP 2022047222A
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- OWIKHYCFFJSOEH-UHFFFAOYSA-N Isocyanic acid Chemical compound N=C=O OWIKHYCFFJSOEH-UHFFFAOYSA-N 0.000 title claims abstract description 55
- XLJMAIOERFSOGZ-UHFFFAOYSA-N anhydrous cyanic acid Natural products OC#N XLJMAIOERFSOGZ-UHFFFAOYSA-N 0.000 title claims abstract description 55
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 37
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 162
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 claims abstract description 111
- 239000003054 catalyst Substances 0.000 claims abstract description 95
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 81
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 81
- 229910021529 ammonia Inorganic materials 0.000 claims abstract description 46
- 150000002681 magnesium compounds Chemical class 0.000 claims abstract description 21
- AXZKOIWUVFPNLO-UHFFFAOYSA-N magnesium;oxygen(2-) Chemical compound [O-2].[Mg+2] AXZKOIWUVFPNLO-UHFFFAOYSA-N 0.000 claims abstract description 13
- 239000000395 magnesium oxide Substances 0.000 claims abstract description 12
- CPLXHLVBOLITMK-UHFFFAOYSA-N magnesium oxide Inorganic materials [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 claims abstract description 12
- VTHJTEIRLNZDEV-UHFFFAOYSA-L magnesium dihydroxide Chemical compound [OH-].[OH-].[Mg+2] VTHJTEIRLNZDEV-UHFFFAOYSA-L 0.000 claims abstract description 10
- ZLNQQNXFFQJAID-UHFFFAOYSA-L magnesium carbonate Chemical compound [Mg+2].[O-]C([O-])=O ZLNQQNXFFQJAID-UHFFFAOYSA-L 0.000 claims abstract description 9
- 239000001095 magnesium carbonate Substances 0.000 claims abstract description 9
- 229910000021 magnesium carbonate Inorganic materials 0.000 claims abstract description 9
- 239000000347 magnesium hydroxide Substances 0.000 claims abstract description 9
- 229910001862 magnesium hydroxide Inorganic materials 0.000 claims abstract description 9
- 239000012948 isocyanate Substances 0.000 claims description 5
- 150000002513 isocyanates Chemical class 0.000 claims description 5
- 238000006243 chemical reaction Methods 0.000 description 55
- 239000007789 gas Substances 0.000 description 39
- 238000010521 absorption reaction Methods 0.000 description 20
- 238000000034 method Methods 0.000 description 19
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 14
- 239000007787 solid Substances 0.000 description 14
- 238000004566 IR spectroscopy Methods 0.000 description 12
- 235000012245 magnesium oxide Nutrition 0.000 description 11
- 230000000717 retained effect Effects 0.000 description 10
- 238000010438 heat treatment Methods 0.000 description 9
- 235000012254 magnesium hydroxide Nutrition 0.000 description 8
- 229910052786 argon Inorganic materials 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 7
- 235000014380 magnesium carbonate Nutrition 0.000 description 7
- 238000005259 measurement Methods 0.000 description 7
- 238000001228 spectrum Methods 0.000 description 7
- 238000000862 absorption spectrum Methods 0.000 description 6
- 238000006297 dehydration reaction Methods 0.000 description 6
- 230000006872 improvement Effects 0.000 description 6
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 6
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 description 5
- 238000002835 absorbance Methods 0.000 description 5
- 239000004202 carbamide Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- 230000009467 reduction Effects 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 4
- 239000002253 acid Substances 0.000 description 4
- 229910052749 magnesium Inorganic materials 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910021536 Zeolite Inorganic materials 0.000 description 3
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 3
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 3
- 239000011777 magnesium Substances 0.000 description 3
- 239000010457 zeolite Substances 0.000 description 3
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- 239000003153 chemical reaction reagent Substances 0.000 description 2
- 229910001873 dinitrogen Inorganic materials 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- -1 magnesium hydroxide Chemical compound 0.000 description 2
- 159000000003 magnesium salts Chemical class 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 235000010755 mineral Nutrition 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 125000004430 oxygen atom Chemical group O* 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000004611 spectroscopical analysis Methods 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910004298 SiO 2 Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052599 brucite Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 238000001354 calcination Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000003795 desorption Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000008187 granular material Substances 0.000 description 1
- 239000001307 helium Substances 0.000 description 1
- 229910052734 helium Inorganic materials 0.000 description 1
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- ZFSLODLOARCGLH-UHFFFAOYSA-N isocyanuric acid Chemical compound OC1=NC(O)=NC(O)=N1 ZFSLODLOARCGLH-UHFFFAOYSA-N 0.000 description 1
- YWXYYJSYQOXTPL-SLPGGIOYSA-N isosorbide mononitrate Chemical compound [O-][N+](=O)O[C@@H]1CO[C@@H]2[C@@H](O)CO[C@@H]21 YWXYYJSYQOXTPL-SLPGGIOYSA-N 0.000 description 1
- 238000000691 measurement method Methods 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000035484 reaction time Effects 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
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Abstract
Description
特許法第３０条第２項適用申請有り （１）令和元年９月１１日発行の第１２４回触媒討論会講演予稿集にて要旨を公開 （２）令和元年９月１９日に第１２４回触媒討論会にてポスター発表 （３）令和元年１１月１８日発行の第３５回近赤外フォーラム講演要旨集にて要旨を公開 （４）令和元年１１月２０日に第３５回近赤外フォーラムにてポスター発表 （５）令和２年３月１０日発行の第１２５回触媒討論会講演予稿集にて要旨を公開There is an application for application of Article 30, Paragraph 2 of the Patent Act (1) The abstract is published in the proceedings of the 124th Catalyst Discussion Meeting issued on September 11, 1st year of Reiwa (2) On September 19, 1st year of Reiwa Poster presentation at the 124th Catalyst Discussion Meeting (3) Abstract published at the 35th Near Infrared Forum Lecture Abstracts published on November 18, 1st year of Reiwa (4) On November 20th, 1st year of Reiwa Poster presentation at the 35th Near Infrared Forum (5) The abstract was published in the proceedings of the 125th Catalyst Discussion Meeting published on March 10, 2nd year of Reiwa.
本発明は、イソシアン酸の製造方法に関する。 The present invention relates to a method for producing isocyanic acid.
イソシアン酸は、尿素からアンモニアを生成する反応過程で生成する比較的不安定な中間生成物であり、例えば、自動車の排気ガス中の窒素酸化物を浄化する尿素ＳＣＲ触媒システム内で生成される化合物である。窒素酸化物の高精度な浄化予測モデルを構築するための一手段としてイソシアン酸の加水分解機構が検討されているところ、その検討を効率的に行うために、イソシアン酸を安定的に製造する技術が望まれる。
イソシアン酸を製造する技術として、例えば非特許文献１では、尿素から得られたシアヌル酸を更に熱分解して、イソシアン酸を生成する方法が開示されている。
Isocyanic acid is a relatively unstable intermediate product produced in the reaction process of producing ammonia from urea, for example, a compound produced in a urea SCR catalytic system that purifies nitrogen oxides in automobile exhaust gas. Is. The hydrolysis mechanism of isocyanic acid is being studied as a means to construct a highly accurate purification prediction model of nitrogen oxides, and in order to carry out the study efficiently, a technology for stably producing isocyanic acid. Is desired.
As a technique for producing isocyanic acid, for example, Non-Patent
しかし、非特許文献１の製造条件では、イソシアン酸の生成量を制御しにくかったり、イソシアン酸以外の副生成物が生成されたりして、イソシアン酸を安定的に製造することができない。また同文献の条件では、尿素などの前駆体を用いる必要があるので、製造工程が煩雑で製造コストが高くなってしまう。
However, under the production conditions of Non-Patent
そこで本発明の課題は、イソシアン酸を低コストで製造可能な製造方法を提供することにある。 Therefore, an object of the present invention is to provide a production method capable of producing isocyanic acid at low cost.
本発明は、マグネシウム化合物を触媒として用い、
前記触媒の存在下で、二酸化炭素とアンモニアとを反応させる工程を有する、イソシアン酸の製造方法を提供するものである。
The present invention uses a magnesium compound as a catalyst.
The present invention provides a method for producing isocyanate, which comprises a step of reacting carbon dioxide with ammonia in the presence of the catalyst.
本発明によれば、イソシアン酸を低コストで製造することができる。 According to the present invention, isocyanic acid can be produced at low cost.
本発明の好適な実施形態を以下に説明する。なお、本発明は以下の実施形態に限定されるものではない。以下の説明では、「Ｘ～Ｙ［Ｚ］」（Ｘ及びＹは任意の数字であり、［Ｚ］は単位である。）と記載した場合、特に断らない限り「Ｘ［Ｚ］以上Ｙ［Ｚ］以下」を意味する。 Suitable embodiments of the present invention will be described below. The present invention is not limited to the following embodiments. In the following description, when "X to Y [Z]" (X and Y are arbitrary numbers and [Z] is a unit) is described, "X [Z] or more Y [" unless otherwise specified. Z] or less.
本発明の製造方法は、Ｈ－Ｎ＝Ｃ＝Ｏの化学構造を有するイソシアン酸を主生成物として製造する方法である。本方法は、マグネシウム化合物を触媒として用い、該触媒の存在下に、二酸化炭素とアンモニアとを反応させる工程を有する。製造効率を高める観点から、触媒は粒状等の固体であることが好ましく、二酸化炭素及びアンモニアはそれぞれ独立して気体であることも好ましい。
以下の説明では、本方法の好適な態様として、触媒として固体のマグネシウム化合物を用い、また気体の二酸化炭素（二酸化炭素ガス）、及び気体のアンモニア（アンモニアガス）を用いた場合を例にとり説明する。
The production method of the present invention is a method for producing isocyanic acid having a chemical structure of HN = C = O as a main product. This method uses a magnesium compound as a catalyst and has a step of reacting carbon dioxide and ammonia in the presence of the catalyst. From the viewpoint of increasing the production efficiency, the catalyst is preferably a solid such as granules, and it is also preferable that carbon dioxide and ammonia are independent gases.
In the following description, as a preferred embodiment of this method, a case where a solid magnesium compound is used as a catalyst, and a gaseous carbon dioxide (carbon dioxide gas) and a gaseous ammonia (ammonia gas) are used will be described as an example. ..
本方法はマグネシウム化合物を触媒として用いることを特徴の一つとしている。本発明者は、比較的不安定な化合物であるイソシアン酸の製造にあたりマグネシウム化合物を触媒として用いることによって、二酸化炭素とアンモニアとの反応が容易に進行し、目的とするイソシアン酸が安定的に製造できることを見出した。以下の反応式（１）に示すように、二酸化炭素及びアンモニアの反応は脱水反応によるものであり、マグネシウム化合物はこの脱水反応を触媒するものである。 One of the features of this method is that a magnesium compound is used as a catalyst. By using a magnesium compound as a catalyst in the production of isocyanic acid, which is a relatively unstable compound, the present inventor facilitates the reaction between carbon dioxide and ammonia, and stably produces the target isocyanic acid. I found out what I could do. As shown in the following reaction formula (1), the reaction of carbon dioxide and ammonia is due to the dehydration reaction, and the magnesium compound catalyzes this dehydration reaction.
本方法に用いられるマグネシウム化合物としては、例えば、酸化マグネシウムなどのマグネシウムの酸化物、水酸化マグネシウムなどのマグネシウムの水酸化物、炭酸マグネシウムなどのマグネシウムの塩等が挙げられる。これらのマグネシウム化合物として、例えば、Ｃｕ等の遷移金属元素を担持させたものを用いてもよく、該遷移金属元素等の他の金属元素を担持しないものを用いてもよい。 Examples of the magnesium compound used in this method include magnesium oxides such as magnesium oxide, magnesium hydroxides such as magnesium hydroxide, and magnesium salts such as magnesium carbonate. As these magnesium compounds, for example, those carrying a transition metal element such as Cu may be used, or those not carrying other metal elements such as the transition metal element may be used.
これらのうち、マグネシウム化合物は、酸化マグネシウム、水酸化マグネシウム及び炭酸マグネシウムのうち少なくとも一種であることが好ましく、マグネシウム以外の金属元素が担持されていないことも好ましい。これらの化合物を用いることによって、触媒、二酸化炭素及びアンモニアの相互反応を良好に進行させることができ、イソシアン酸を効率的に且つ安定的に製造することができる。マグネシウム化合物として酸化マグネシウムを用いる場合には、水酸化マグネシウムや炭酸マグネシウムの表面を酸化させたものを用いてもよく、あるいは酸化マグネシウムそのものを用いてもよい。マグネシウム化合物の比表面積を高くして、二酸化炭素及びアンモニアの反応を効率的に進行させる観点から、水酸化マグネシウムや炭酸マグネシウムを焼成したものを用いることが好ましい。 Of these, the magnesium compound is preferably at least one of magnesium oxide, magnesium hydroxide and magnesium carbonate, and it is also preferable that no metal element other than magnesium is carried. By using these compounds, the mutual reaction between the catalyst, carbon dioxide and ammonia can be satisfactorily promoted, and isocyanic acid can be efficiently and stably produced. When magnesium oxide is used as the magnesium compound, magnesium hydroxide or a magnesium carbonate whose surface is oxidized may be used, or magnesium oxide itself may be used. From the viewpoint of increasing the specific surface area of the magnesium compound and efficiently advancing the reaction between carbon dioxide and ammonia, it is preferable to use a fired magnesium hydroxide or magnesium carbonate.
上述したマグネシウム化合物を用いることによってイソシアン酸の生成が良好に進行する理由について、本発明者は以下のように推測している。
図１に示すように、上述したマグネシウム化合物は、常温条件又は加熱条件下において、化学構造中にマグネシウム原子と結合している酸素原子や水酸基を有しており、化合物の表面が塩基となっている部位（塩基点）が存在する。このような化合物を触媒として用いることによって、塩基点としての酸素原子又は水酸基と、酸としての二酸化炭素分子とが反応する。その結果、触媒であるマグネシウム化合物の表面に二酸化炭素吸着種が生成する。その状態で、二酸化炭素吸着種とアンモニアとが反応することにより、二酸化炭素分子とアンモニア分子との間で脱水反応が進行し、イソシアン酸が生成する。
The present inventor speculates that the reason why the production of isocyanic acid proceeds satisfactorily by using the above-mentioned magnesium compound is as follows.
As shown in FIG. 1, the above-mentioned magnesium compound has an oxygen atom or a hydroxyl group bonded to a magnesium atom in a chemical structure under normal temperature conditions or heating conditions, and the surface of the compound becomes a base. There is a site (base point). By using such a compound as a catalyst, an oxygen atom or a hydroxyl group as a base point reacts with a carbon dioxide molecule as an acid. As a result, carbon dioxide adsorbed species are generated on the surface of the magnesium compound that is the catalyst. In that state, the reaction between the carbon dioxide adsorbed species and ammonia promotes a dehydration reaction between the carbon dioxide molecules and the ammonia molecules, and isocyanic acid is produced.
触媒がその表面に水酸基を有することは、例えば赤外分光法（ＩＲ）による測定において、３８００～３１００ｃｍ－１に吸収ピークが観察されることによって判定することができる。この吸収ピークが存在することは、触媒表面に酸化マグネシウムが存在していることと同視できる。
なお本明細書において「吸収ピークが観察される」とは、所定の波数の範囲内において、強度が極大値を示すピークの頂点（ピークトップ）を有することを意味する。またピークトップは、ベースラインの吸光度を基準としたときに、ベースラインの吸光度よりも０．０３より大きい吸光度の差が観察されたものを指す。
The fact that the catalyst has a hydroxyl group on its surface can be determined by observing an absorption peak at 3800 to 3100 cm -1 , for example, in a measurement by infrared spectroscopy (IR). The presence of this absorption peak can be equated with the presence of magnesium oxide on the catalyst surface.
In the present specification, "the absorption peak is observed" means that the peak has a peak (peak top) at which the intensity shows a maximum value within a predetermined wave number range. Further, the peak top refers to the one in which a difference in absorbance larger than 0.03 is observed from the absorbance at the baseline when the absorbance at the baseline is used as a reference.
また触媒表面に二酸化炭素が吸着して吸着種が生成したことは、例えばＩＲ測定において、２４００～２３００ｃｍ－１に吸収ピークが観察されることによって判定することができる。 Further, it can be determined that carbon dioxide is adsorbed on the catalyst surface to generate an adsorbed species, for example, by observing an absorption peak at 2400 to 2300 cm -1 in IR measurement.
触媒の比表面積は、反応効率の向上の観点からは高ければ高いほど好ましいが、反応効率の向上と原料コストの低減との両立を図る観点から、ＢＥＴ比表面積で表して、好ましくは６．０～４００ｍ２／ｇ、更に好ましくは９０～４００ｍ２／ｇである。このような比表面積を有することによって、二酸化炭素が吸着保持するための触媒表面を十分に確保することができ、イソシアン酸の生成効率が更に向上する。触媒の比表面積は、例えばＪＩＳ Ｚ８８３０：２０１３に準じて、ＢＥＴ１点法により測定することができる。 The higher the specific surface area of the catalyst is, the more preferable it is from the viewpoint of improving the reaction efficiency, but from the viewpoint of achieving both the improvement of the reaction efficiency and the reduction of the raw material cost, it is preferably 6.0 in terms of the BET specific surface area. It is ~ 400 m 2 / g, more preferably 90 ~ 400 m 2 / g. By having such a specific surface area, it is possible to sufficiently secure a catalyst surface for adsorbing and retaining carbon dioxide, and the efficiency of producing isocyanic acid is further improved. The specific surface area of the catalyst can be measured by the BET 1-point method according to, for example, JIS Z8830: 2013.
このような比表面積を有する触媒としては、例えば、海水法によって生成された水酸化マグネシウムや、天然鉱物の一種であるブルーサイトの粉砕物を用いることができる。また、マグネシウム塩水溶液に炭酸ナトリウムまたは炭酸カリウムを加えて生成した沈殿物を乾燥して得られる塩基性炭酸マグネシウムや、天然鉱物の一種であるマグネサイトの粉砕物を用いることもできる。
また、一例として特開２０２０－６３１８５号公報に記載されているような、水酸化マグネシウムを外熱式ロータリーキルンによって加熱焼成して得られた酸化マグネシウムを用いることもできる。加熱焼成の条件は、例えば４００～７５０℃で３０分未満とすることができる。
As the catalyst having such a specific surface area, for example, magnesium hydroxide produced by the seawater method or crushed brucite, which is a kind of natural mineral, can be used. Further, basic magnesium carbonate obtained by drying a precipitate produced by adding sodium carbonate or potassium carbonate to an aqueous magnesium salt solution, or a pulverized product of magnesite, which is a kind of natural mineral, can also be used.
Further, as an example, magnesium oxide obtained by heating and calcining magnesium hydroxide with an external heat type rotary kiln as described in Japanese Patent Application Laid-Open No. 2020-63185 can also be used. The heating and firing conditions can be, for example, 400 to 750 ° C. for less than 30 minutes.
本方法の触媒存在下での各種ガスの反応方法は、例えば、触媒として粉末状又は錠剤形等の所定形状のマグネシウム化合物を収容した容器に各種ガスを流通させたり、又は各種ガスが流通若しくは収容されている容器内に、マグネシウム化合物を導入したりすることによって行うことができる。流通させる各種ガスの濃度調整を行うために、ヘリウムやアルゴンなどの希ガスを反応系に共存させることは妨げられない。 In the reaction method of various gases in the presence of a catalyst of this method, for example, various gases are circulated in a container containing a magnesium compound having a predetermined shape such as powder or tablet as a catalyst, or various gases are circulated or contained. This can be done by introducing a magnesium compound into the container. In order to adjust the concentration of various gases to be circulated, it is not hindered to allow rare gases such as helium and argon to coexist in the reaction system.
触媒存在下での二酸化炭素ガスとアンモニアガスとの反応方法は、例えば触媒に対して、二酸化炭素及びアンモニアを同時に導入して反応させてもよい。また、触媒と二酸化炭素とを接触させて触媒に二酸化炭素を吸着させた後、吸着された状態にある二酸化炭素とアンモニアとを反応させてもよい。あるいは、アンモニアを触媒に吸着させた後、吸着された状態にあるアンモニアと二酸化炭素とを反応させてもよい。
これらのうち、触媒と二酸化炭素とを接触させて触媒表面に二酸化炭素を吸着させた後、触媒表面に吸着された状態にある二酸化炭素とアンモニアとを接触させて、イソシアン酸の生成反応を開始することが好ましい。このような順序を経て反応を開始することによって、塩基点を有する触媒の表面に二酸化炭素が十分に吸着保持されるので、二酸化炭素とアンモニアとを触媒表面及びその近傍で効率的に反応させることができる。その結果、イソシアン酸を低コストで且つより安定的に得ることができる。
As a method of reacting carbon dioxide gas and ammonia gas in the presence of a catalyst, for example, carbon dioxide and ammonia may be simultaneously introduced into the catalyst to react. Alternatively, the catalyst may be brought into contact with carbon dioxide to adsorb carbon dioxide to the catalyst, and then the adsorbed carbon dioxide may be reacted with ammonia. Alternatively, after adsorbing ammonia on the catalyst, the adsorbed ammonia may be reacted with carbon dioxide.
Of these, carbon dioxide is brought into contact with the catalyst to adsorb carbon dioxide on the surface of the catalyst, and then carbon dioxide adsorbed on the surface of the catalyst is brought into contact with ammonia to initiate an isocyanic acid production reaction. It is preferable to do so. By starting the reaction in such an order, carbon dioxide is sufficiently adsorbed and retained on the surface of the catalyst having a base point, so that carbon dioxide and ammonia can be efficiently reacted on or near the catalyst surface. Can be done. As a result, isocyanic acid can be obtained more stably at low cost.
本方法は、少なくとも反応開始時において、二酸化炭素とアンモニアとがともに加熱されていることが好ましい。これによって、二酸化炭素とアンモニアとの脱水反応が良好に進行し、イソシアン酸の生成をより効率的に行うことができる。上述した好適な反応順序において、触媒への二酸化炭素の吸着においては、常温で反応させてもよく、加熱下で反応させてもよい。温度制御を各工程で不要として、製造工程を少なくして生産性をより高める観点から、反応開始から反応終了まで、触媒、二酸化炭素及びアンモニアの全てが加熱されていることがより好ましい。 In this method, it is preferable that both carbon dioxide and ammonia are heated at least at the start of the reaction. As a result, the dehydration reaction between carbon dioxide and ammonia proceeds satisfactorily, and isocyanic acid can be produced more efficiently. In the above-mentioned suitable reaction sequence, in the adsorption of carbon dioxide to the catalyst, the reaction may be carried out at room temperature or under heating. From the viewpoint of eliminating the need for temperature control in each step and reducing the number of manufacturing steps to further increase productivity, it is more preferable that all of the catalyst, carbon dioxide and ammonia are heated from the start of the reaction to the end of the reaction.
より具体的には、触媒を含む反応容器を所定温度での加熱状態を維持しておき、該反応容器に対して、常温等の非加熱の二酸化炭素とアンモニアとを導入して、加熱状態で反応させてもよい。これに代えて、触媒を含む反応容器を所定温度での加熱状態を維持しておき、該反応容器に対して、所定温度に加熱した二酸化炭素とアンモニアとを反応させてもよい。あるいは、触媒としてのマグネシウム化合物を反応開始前に予め加熱して前処理を行った後で、所定温度での加熱状態が維持された触媒を含む反応容器内に、二酸化炭素及びアンモニアを非加熱又は加熱状態で導入して反応させてもよい。
特に、反応開始前に触媒を予め加熱しておくことによって、触媒表面に酸化マグネシウムを多く生成させることができ、またこれに伴って、塩基点をより多く形成させて、二酸化炭素の触媒表面への保持をより効率的に行うことができる。その結果、二酸化炭素とアンモニアとの脱水反応を一度の工程で効率的に進行させることができる点で有利である。
More specifically, the reaction vessel containing the catalyst is maintained in a heated state at a predetermined temperature, and unheated carbon dioxide and ammonia at room temperature or the like are introduced into the reaction vessel in a heated state. It may be reacted. Alternatively, the reaction vessel containing the catalyst may be kept heated at a predetermined temperature, and the reaction vessel may be reacted with carbon dioxide heated to the predetermined temperature and ammonia. Alternatively, carbon dioxide and ammonia are unheated or placed in a reaction vessel containing a catalyst maintained in a heated state at a predetermined temperature after pretreatment by preheating a magnesium compound as a catalyst before starting the reaction. It may be introduced in a heated state and reacted.
In particular, by preheating the catalyst before the start of the reaction, a large amount of magnesium oxide can be generated on the catalyst surface, and along with this, more base points are formed on the surface of the carbon dioxide catalyst. Can be held more efficiently. As a result, it is advantageous that the dehydration reaction between carbon dioxide and ammonia can be efficiently proceeded in one step.
本方法における加熱温度は、反応系全体として、好ましくは１００℃超６００℃以下、より好ましくは１５０～５００℃、更に好ましくは２００～４００℃に加熱した状態が維持されることが好ましい。このような温度範囲にあることによって、触媒に吸着保持された二酸化炭素の脱離を防止しつつ、熱による分子運動の向上に起因して二酸化炭素とアンモニアとの脱水反応を良好に進行させることができるので、イソシアン酸を安定的に生成させることができ、また生成効率が更に向上する。 The heating temperature in this method is preferably maintained at a temperature of more than 100 ° C. and 600 ° C. or lower, more preferably 150 to 500 ° C., and even more preferably 200 to 400 ° C. for the entire reaction system. By being in such a temperature range, it is possible to prevent the desorption of carbon dioxide adsorbed and retained by the catalyst, and to promote the dehydration reaction between carbon dioxide and ammonia satisfactorily due to the improvement of molecular motion due to heat. Therefore, isocyanic acid can be stably produced, and the production efficiency is further improved.
本方法における触媒、二酸化炭素ガス及びアンモニアガスの反応時間は、目的とするイソシアン酸が生成される限りにおいて適宜変更可能であるが、イソシアン酸の生産効率の向上と製造コストの低減との両立を図る観点から、上述した加熱温度の範囲において、好ましくは１分～２時間、より好ましくは１分～１．５時間、更に好ましくは１分～１時間である。 The reaction times of the catalyst, carbon dioxide gas, and ammonia gas in this method can be appropriately changed as long as the target isocyanic acid is produced, but both improvement of the production efficiency of isocyanic acid and reduction of the production cost are achieved. From the viewpoint, it is preferably 1 minute to 2 hours, more preferably 1 minute to 1.5 hours, and further preferably 1 minute to 1 hour in the above-mentioned heating temperature range.
触媒を予め加熱する場合、触媒の加熱温度は、好ましくは２００～１３００℃、更に好ましくは４００～８００℃である。このような温度で触媒を加熱処理することで、触媒表面に塩基点を更に多く形成させて、二酸化炭素の触媒表面への保持をより効率的に行うことができる。その結果、イソシアン酸の生成効率が更に向上する。 When the catalyst is preheated, the heating temperature of the catalyst is preferably 200 to 1300 ° C, more preferably 400 to 800 ° C. By heat-treating the catalyst at such a temperature, more base points can be formed on the catalyst surface, and carbon dioxide can be more efficiently retained on the catalyst surface. As a result, the production efficiency of isocyanic acid is further improved.
本方法における圧力条件は、大気圧下であってもよく、真空などの陰圧下において触媒表面の吸着ガスを脱離させ清浄した後、反応系内の気体として二酸化炭素ガス及びアンモニアガスのみが存在するように各ガスを導入してもよく、大気圧よりも高い圧力に加圧した陽圧下であってもよい。特別な製造設備を別途用意せずとも反応を良好に進行させて、製造コストを低減する観点から、本方法は、反応開始から反応終了まで、大気圧下で行うことが好ましい。
また本方法における雰囲気条件は、大気雰囲気であってもよく、窒素ガスや希ガス等の不活性ガス雰囲気であってもよく、水素ガス等の還元雰囲気であってもよい。製造コストを低減する観点から、反応開始から反応終了まで、大気雰囲気で行うことが好ましい。特に、大気雰囲気で行うことによって、大気中に存在する二酸化炭素を触媒表面に微量に吸着させることができるので、二酸化炭素を別途導入することと相まって、アンモニアとの反応が良好に進行し、イソシアン酸の生成効率が更に向上するという利点も奏される。
製造コストの低減と、イソシアン酸の生成効率の向上との高いレベルでの両立を図る観点から、本方法は、反応開始から反応終了まで、大気雰囲気且つ大気圧下で行うことが更に好ましい。
The pressure condition in this method may be under atmospheric pressure, and after desorbing and cleaning the adsorbed gas on the catalyst surface under negative pressure such as vacuum, only carbon dioxide gas and ammonia gas are present as gases in the reaction system. Each gas may be introduced as such, or may be under positive pressure pressurized to a pressure higher than the atmospheric pressure. From the viewpoint of satisfactorily proceeding with the reaction and reducing the manufacturing cost without separately preparing special manufacturing equipment, this method is preferably carried out under atmospheric pressure from the start to the end of the reaction.
Further, the atmospheric condition in this method may be an atmospheric atmosphere, an inert gas atmosphere such as nitrogen gas or a rare gas, or a reducing atmosphere such as hydrogen gas. From the viewpoint of reducing the manufacturing cost, it is preferable to carry out from the start of the reaction to the end of the reaction in an atmospheric atmosphere. In particular, by performing in an atmospheric atmosphere, carbon dioxide existing in the atmosphere can be adsorbed on the catalyst surface in a small amount, so that the reaction with ammonia proceeds well in combination with the introduction of carbon dioxide separately, and isocyanic acid. It also has the advantage of further improving the efficiency of acid production.
From the viewpoint of achieving both a reduction in production cost and an improvement in the production efficiency of isocyanic acid at a high level, it is more preferable that this method is carried out in an atmospheric atmosphere and at atmospheric pressure from the start to the end of the reaction.
反応時における二酸化炭素ガスの流量は、製造コストの低減と、イソシアン酸の生成効率の向上とを両立する観点から、例えば触媒質量３０ｍｇ当たり、好ましくは０．０２～１００ｍＬ／ｍｉｎであり、より好ましくは１～１００ｍＬ／ｍｉｎであり、更に好ましくは１～４０ｍＬ／ｍｉｎである。二酸化炭素ガスの流量は、２５℃、１気圧での値とする。 The flow rate of carbon dioxide gas during the reaction is, for example, preferably 0.02 to 100 mL / min per 30 mg of catalyst mass, more preferably, from the viewpoint of achieving both reduction of production cost and improvement of isocyanic acid production efficiency. Is 1 to 100 mL / min, more preferably 1 to 40 mL / min. The flow rate of carbon dioxide gas shall be a value at 25 ° C. and 1 atm.
また同様の観点から、反応時におけるアンモニアガスの流量は、製造コストの低減と、イソシアン酸の生成効率の向上とを両立する観点から、例えば触媒質量３０ｍｇ当たり、好ましくは０．０２～１００ｍＬ／ｍｉｎであり、より好ましくは０．０２～１０ｍＬ／ｍｉｎであり、更に好ましくは０．０２～２ｍＬ／ｍｉｎである。アンモニアガスの流量は、２５℃、１気圧での値とする。また、アンモニアガスが希ガスなどの他の気体によって希釈されて導入される場合、アンモニアガスの流量は、混合体積比に応じて算出された値とする。 From the same viewpoint, the flow rate of ammonia gas during the reaction is preferably 0.02 to 100 mL / min per 30 mg of catalyst mass, for example, from the viewpoint of achieving both reduction of production cost and improvement of isocyanic acid production efficiency. It is more preferably 0.02 to 10 mL / min, and even more preferably 0.02 to 2 mL / min. The flow rate of ammonia gas is a value at 25 ° C. and 1 atm. When the ammonia gas is diluted with another gas such as a rare gas and introduced, the flow rate of the ammonia gas shall be a value calculated according to the mixed volume ratio.
以上の工程を経て、イソシアン酸を製造することができる。生成したイソシアン酸は、典型的には触媒表面に存在するか、又は気体となって反応系中に存在する。イソシアン酸が生成したことは、例えばＩＲ測定において、２３００～２１００ｃｍ－１、より具体的には２２５０～２１５０ｃｍ－１に吸収ピークが観察されることによって判定することができる。またイソシアン酸の生成量は、ベースラインの吸光度を基準として、前記吸収ピークにおける吸光度（ピーク高さ）が大きければ大きいほど生成量が多いと推定される。 Isocyanic acid can be produced through the above steps. The generated isocyanate is typically present on the surface of the catalyst or in the form of a gas in the reaction system. The formation of isocyanic acid can be determined, for example, by observing an absorption peak at 2300 to 2100 cm -1 , more specifically 2250 to 2150 cm -1 in IR measurement. Further, it is estimated that the larger the absorbance (peak height) at the absorption peak, the larger the amount of isocyanic acid produced, based on the absorbance at the baseline.
以下、実施例により本発明を更に詳細に説明する。本発明の範囲は、かかる実施例に制限されない。
以下に示すＩＲ測定は、フーリエ変換赤外線吸収分光光度計（日本分光製、ＦＴ／ＩＲ－６６０Ｐｌｕｓ；以下、これを「ＦＴ－ＩＲ計」ともいう。）、及びＦＴ－ＩＲ計に接続された加熱拡散反射測定装置（日本分光製；以下これを「拡散反射装置」ともいう。）を用いて、分解能：４ｃｍ－１、スキャン：２５６回で試料（触媒）のＩＲ拡散反射スペクトルを測定したものである。バックグラウンド測定は、乾燥したＫＢｒ粉末を用いて測定前に予め行った。
Hereinafter, the present invention will be described in more detail by way of examples. The scope of the invention is not limited to such examples.
The IR measurements shown below are the heating connected to a Fourier-converted infrared absorption spectrophotometer (manufactured by Nippon Spectroscopy, FT / IR-660Plus; hereinafter also referred to as "FT-IR meter") and an FT-IR meter. The IR diffuse reflection spectrum of the sample (catalyst) was measured with a resolution of 4 cm -1 and scans of 256 times using a diffuse reflection measuring device (manufactured by Nippon Spectroscopy; hereinafter also referred to as "diffuse reflecting device"). be. Background measurement was performed in advance using dried KBr powder before measurement.
〔実施例１〕
３０ｍｇの水酸化マグネシウム（ナカライテスク社製、試薬特級）を錠剤成形して、直径約５ｍｍ及び高さ約１ｍｍの円盤状の固形物を得た。この固形物を、拡散反射装置の試料台に配置した。そして、該試料台に付属している温度コントローラを用いて、室温から６００℃に昇温し、大気雰囲気及び大気圧下にて６００℃にて固形物を１時間予め加熱処理し、表面に酸化マグネシウムを有する触媒を得た。
次いで、触媒を２００℃に降温して維持したあと、大気雰囲気及び大気圧下にて常温（２５℃）の二酸化炭素ガスを３０ｍＬ／ｍｉｎの流量で、マスフローコントローラ（コフロック製）を用いて、２００℃に維持された試料台内に２０分間流通させて、触媒表面に二酸化炭素を吸着保持させた。
そして、大気雰囲気及び大気圧下にて常温（２５℃）の１体積％アンモニアガス／９９体積％のアルゴンガスの混合ガスを２ｍＬ／ｍｉｎ（アンモニアガス：０．０２ｍＬ／ｍｉｎ）の流量で、マスフローコントローラ（コフロック製）を用いて、２００℃に維持された試料台内に６０分間流通させて、触媒表面に吸着保持された二酸化炭素とアンモニアとを加熱状態を維持して反応させて、イソシアン酸を得た。
本実施例において、反応終了後の触媒を対象として、ＩＲ拡散反射スペクトルを取得した結果を図２に示す。同図に示すように、本実施例では、二酸化炭素の流通によって２４００～２３００ｃｍ－１の範囲に二酸化炭素の吸収ピークが観察された。そして、アンモニアの流通後、２２０７ｃｍ－１及び２１９３ｃｍ－１にイソシアン酸に基づく吸収ピークが観測された。
[Example 1]
30 mg of magnesium hydroxide (manufactured by Nacalai Tesque, special grade reagent) was tablet-molded to obtain a disk-shaped solid having a diameter of about 5 mm and a height of about 1 mm. This solid matter was placed on the sample table of the diffuse reflector. Then, using the temperature controller attached to the sample table, the temperature is raised from room temperature to 600 ° C., and the solid substance is preheated for 1 hour at 600 ° C. under atmospheric atmosphere and atmospheric pressure, and the surface is oxidized. A catalyst with magnesium was obtained.
Then, after lowering the temperature of the catalyst to 200 ° C. and maintaining it, carbon dioxide gas at room temperature (25 ° C.) was applied at a flow rate of 30 mL / min under an atmospheric atmosphere and atmospheric pressure using a mass flow controller (manufactured by Cofflock) for 200. Carbon dioxide was adsorbed and held on the surface of the catalyst by circulating it in a sample table maintained at ° C for 20 minutes.
Then, a mixed gas of 1% by volume ammonia gas / 99% by volume argon gas at room temperature (25 ° C.) under atmospheric atmosphere and atmospheric pressure is mass flowed at a flow rate of 2 mL / min (ammonia gas: 0.02 mL / min). Using a controller (manufactured by Cofflock), the gas is circulated in a sample table maintained at 200 ° C. for 60 minutes, and the carbon dioxide adsorbed and retained on the surface of the catalyst and ammonia are reacted while maintaining a heated state to cause isocyanic acid. Got
In this example, FIG. 2 shows the results of acquiring the IR diffuse reflection spectrum of the catalyst after the reaction is completed. As shown in the figure, in this example, the absorption peak of carbon dioxide was observed in the range of 2400 to 2300 cm -1 due to the circulation of carbon dioxide. Then, after the circulation of ammonia, absorption peaks based on isocyanic acid were observed at 2207 cm -1 and 2193 cm -1 .
〔実施例２〕
実施例１と同様の条件で、錠剤成形した固形物を加熱処理して、表面に酸化マグネシウムを有する触媒を得た。次いで、触媒を３００℃に降温して維持したあと、大気雰囲気及び大気圧下にて常温（２５℃）の二酸化炭素ガスを、実施例１と同様の流量条件で３００℃に維持された試料台内に流通させ、触媒表面に二酸化炭素を吸着保持させた。そして、大気雰囲気及び大気圧下にて常温（２５℃）の１体積％アンモニアガス／９９体積％のアルゴンガスの混合ガスを実施例１と同様の流量条件で３００℃に維持された試料台内に流通させ、触媒表面に保持された二酸化炭素とアンモニアとを加熱状態を維持して反応させて、イソシアン酸を得た。
本実施例において、反応終了後の触媒を対象として、ＩＲ拡散反射スペクトルを取得した結果を図３に示す。同図に示すように、本実施例では、二酸化炭素の流通によって２４００～２３００ｃｍ－１の範囲に二酸化炭素の吸収ピークが観察された。そして、アンモニアの流通後、２２１４ｃｍ－１及び２１９３ｃｍ－１にイソシアン酸に基づく吸収ピークが観測された。
[Example 2]
The tablet-molded solid was heat-treated under the same conditions as in Example 1 to obtain a catalyst having magnesium oxide on the surface. Next, after the temperature of the catalyst was lowered to 300 ° C. and maintained, the carbon dioxide gas at room temperature (25 ° C.) was maintained at 300 ° C. under the same flow conditions as in Example 1 under the atmospheric atmosphere and atmospheric pressure. It was circulated inside and carbon dioxide was adsorbed and retained on the surface of the catalyst. Then, in the sample table, a mixed gas of 1% by volume ammonia gas / 99% by volume argon gas at room temperature (25 ° C.) was maintained at 300 ° C. under the same flow rate conditions as in Example 1 under the atmosphere and atmospheric pressure. The carbon dioxide retained on the surface of the catalyst and ammonia were reacted while maintaining a heated state to obtain isocyanic acid.
In this example, the result of acquiring the IR diffuse reflection spectrum for the catalyst after the reaction is shown in FIG. As shown in the figure, in this example, the absorption peak of carbon dioxide was observed in the range of 2400 to 2300 cm -1 due to the circulation of carbon dioxide. Then, after the circulation of ammonia, absorption peaks based on isocyanic acid were observed at 2214 cm -1 and 2193 cm -1 .
〔実施例３〕
実施例１と同様の条件で、錠剤成形した固形物を加熱処理して、表面に酸化マグネシウムを有する触媒を得た。次いで、触媒を４００℃に降温して維持したあと、大気雰囲気及び大気圧下にて常温（２５℃）の二酸化炭素ガスを、実施例１と同様の流量条件で４００℃に維持された試料台内に流通させ、触媒表面に二酸化炭素を吸着保持させた。そして、大気雰囲気及び大気圧下にて常温（２５℃）の１体積％アンモニアガス／９９体積％のアルゴンガスの混合ガスを実施例１と同様の流量条件で４００℃に維持された試料台内に流通させ、触媒表面に保持された二酸化炭素とアンモニアとを加熱状態を維持して反応させて、イソシアン酸を得た。
本実施例において、反応終了後の触媒を対象として、ＩＲ拡散反射スペクトルを取得した結果を図４に示す。同図に示すように、本実施例では、二酸化炭素の流通によって２４００～２３００ｃｍ－１の範囲に二酸化炭素の吸収ピークが観察された。そして、アンモニアの流通後、２２１２ｃｍ－１及び２１９２ｃｍ－１にイソシアン酸に基づく吸収ピークが観測された。
[Example 3]
The tablet-molded solid was heat-treated under the same conditions as in Example 1 to obtain a catalyst having magnesium oxide on the surface. Next, after the temperature of the catalyst was lowered to 400 ° C. and maintained, the carbon dioxide gas at room temperature (25 ° C.) was maintained at 400 ° C. under the same flow conditions as in Example 1 under the atmospheric atmosphere and atmospheric pressure. It was circulated inside and carbon dioxide was adsorbed and retained on the surface of the catalyst. Then, in the sample table, a mixed gas of 1% by volume ammonia gas / 99% by volume argon gas at room temperature (25 ° C.) was maintained at 400 ° C. under the same flow rate conditions as in Example 1 under the atmosphere and atmospheric pressure. The carbon dioxide retained on the surface of the catalyst and ammonia were reacted while maintaining a heated state to obtain isocyanic acid.
In this example, FIG. 4 shows the results of acquiring the IR diffuse reflection spectrum of the catalyst after the reaction is completed. As shown in the figure, in this example, the absorption peak of carbon dioxide was observed in the range of 2400 to 2300 cm -1 due to the circulation of carbon dioxide. Then, after the circulation of ammonia, absorption peaks based on isocyanic acid were observed at 2212 cm -1 and 2192 cm -1 .
〔実施例４〕
実施例１と同様の条件で、錠剤成形した固形物を加熱処理して、表面に酸化マグネシウムを有する触媒を得た。次いで、触媒を６００℃に維持したあと、大気雰囲気及び大気圧下にて常温（２５℃）の二酸化炭素ガスを４０ｍＬ／ｍｉｎの流量で１０分間、６００℃に維持された試料台内に流通させ、触媒表面に二酸化炭素を吸着保持させた。そして、大気雰囲気及び大気圧下にて常温（２５℃）の１体積％アンモニアガス／９９体積％のアルゴンガスの混合ガスを１０ｍＬ／ｍｉｎ（アンモニアガス：０．１ｍＬ／ｍｉｎ）の流量で１０分間、６００℃に維持された試料台内に流通させ、触媒表面に保持された二酸化炭素とアンモニアとを加熱状態を維持して反応させて、イソシアン酸を得た。
本実施例において、反応終了後の触媒を対象として、ＩＲ拡散反射スペクトルを取得した結果を図５に示す。同図に示すように、本実施例では、二酸化炭素の流通によって２４００～２３００ｃｍ－１の範囲に二酸化炭素の吸収ピークが観察された。そして、アンモニアの流通後、２２００ｃｍ－１にイソシアン酸に基づく吸収ピークが観測された。
[Example 4]
The tablet-molded solid was heat-treated under the same conditions as in Example 1 to obtain a catalyst having magnesium oxide on the surface. Next, after maintaining the catalyst at 600 ° C., carbon dioxide gas at room temperature (25 ° C.) was circulated in the sample table maintained at 600 ° C. for 10 minutes at a flow rate of 40 mL / min under atmospheric atmosphere and atmospheric pressure. , Carbon dioxide was adsorbed and retained on the catalyst surface. Then, under atmospheric atmosphere and atmospheric pressure, a mixed gas of 1% by volume ammonia gas / 99% by volume argon gas at room temperature (25 ° C.) was mixed at a flow rate of 10 mL / min (ammonia gas: 0.1 mL / min) for 10 minutes. , It was circulated in a sample table maintained at 600 ° C., and the carbon dioxide held on the surface of the catalyst and ammonia were reacted while maintaining a heated state to obtain isocyanic acid.
In this example, the result of acquiring the IR diffuse reflection spectrum for the catalyst after the reaction is shown in FIG. As shown in the figure, in this example, the absorption peak of carbon dioxide was observed in the range of 2400 to 2300 cm -1 due to the circulation of carbon dioxide. Then, after the circulation of ammonia, an absorption peak based on isocyanic acid was observed at 2200 cm -1 .
〔実施例５〕
３０ｍｇの塩基性炭酸マグネシウム（キシダ化学製、試薬特級）を錠剤成形して、実施例１と同様の寸法を有する円盤状の固形物を得た。この固形物を、拡散反射装置の試料台に配置した。そして、該試料台に付属している温度コントローラを用いて室温から５００℃に昇温し、大気雰囲気及び大気圧下にて、固形物を５００℃にて１時間加熱処理して、表面に酸化マグネシウムを有する触媒を得た。
次いで、触媒を５００℃に降温して維持したあと、大気雰囲気及び大気圧下にて常温（２５℃）の二酸化炭素ガスを４０ｍＬ／ｍｉｎの流量で１０分間、５００℃に維持された試料台内に流通させ、触媒表面に二酸化炭素を吸着保持させた。そして、大気雰囲気及び大気圧下にて常温（２５℃）の１体積％アンモニアガス／９９体積％のアルゴンガスの混合ガスを１０ｍＬ／ｍｉｎ（アンモニアガス：０．１ｍＬ／ｍｉｎ）の流量で１０分間、５００℃に維持された試料台内に流通させ、触媒表面に保持された二酸化炭素とアンモニアとを加熱状態を維持して反応させて、イソシアン酸を得た。
本実施例において、反応終了後の触媒を対象として、ＩＲ拡散反射スペクトルを取得した結果を図６に示す。同図に示すように、本実施例では、２１８４ｃｍ－１にイソシアン酸に基づく吸収ピークが観測された。
[Example 5]
30 mg of basic magnesium carbonate (manufactured by Kishida Chemical Co., Ltd., reagent special grade) was tablet-molded to obtain a disk-shaped solid having the same dimensions as in Example 1. This solid matter was placed on the sample table of the diffuse reflector. Then, the temperature is raised from room temperature to 500 ° C. using the temperature controller attached to the sample table, and the solid substance is heat-treated at 500 ° C. for 1 hour under atmospheric atmosphere and atmospheric pressure to oxidize the surface. A catalyst with magnesium was obtained.
Next, after the catalyst was cooled to 500 ° C. and maintained, carbon dioxide gas at room temperature (25 ° C.) was maintained at 500 ° C. for 10 minutes at a flow rate of 40 mL / min under atmospheric atmosphere and atmospheric pressure in the sample table. The carbon dioxide was adsorbed and retained on the surface of the catalyst. Then, under atmospheric atmosphere and atmospheric pressure, a mixed gas of 1% by volume ammonia gas / 99% by volume argon gas at room temperature (25 ° C.) was mixed at a flow rate of 10 mL / min (ammonia gas: 0.1 mL / min) for 10 minutes. , It was circulated in a sample table maintained at 500 ° C., and the carbon dioxide held on the surface of the catalyst and ammonia were reacted while maintaining a heated state to obtain isocyanic acid.
In this example, FIG. 6 shows the results of acquiring the IR diffuse reflection spectrum of the catalyst after the reaction is completed. As shown in the figure, in this example, an absorption peak based on isocyanic acid was observed at 2184 cm -1 .
〔比較例１〕
ナトリウム型ゼオライト（Ｎａ－ＺＳＭ－５、東ソー製、ＳｉＯ２／Ａｌ２Ｏ３質量比＝２３．８）をイオン交換して、ＮＨ４型ゼオライト（ＮＨ４－ＺＳＭ－５）を作製した。次いで、３０ｍｇのＮＨ４－ＺＳＭ－５を錠剤成形して、実施例１と同様の寸法を有する円盤状の固形物を得た。この固形物を、拡散反射装置の試料台に配置した。そして、該試料台に付属している温度コントローラを用いて室温から６００℃に昇温し、大気雰囲気及び大気圧下にて６００℃にて固形物を１時間加熱処理し、触媒としてのプロトン型ゼオライト（Ｈ－ＺＳＭ－５）を得た。この触媒は、表面が酸となっている部位（酸点）が存在しており、塩基点は形成されていない。
次いで、触媒を３００℃に降温して維持して、大気雰囲気及び大気圧下にて常温（２５℃）の二酸化炭素ガスを４０ｍＬ／ｍｉｎの流量で１０分間、３００℃に維持された試料台内に流通させた後、大気雰囲気及び大気圧下にて常温（２５℃）の１体積％アンモニアガス／９９体積％のアルゴンガスの混合ガスを１０ｍＬ／ｍｉｎ（アンモニアガス：０．１ｍＬ／ｍｉｎ）の流量で１０分間、３００℃に維持された試料台内に流通させた。
本比較例において、反応終了後の触媒を対象として、ＩＲ拡散反射スペクトルを取得した結果を図７に示す。同図に示すように、本比較例では、二酸化炭素の流通によって２４００～２３００ｃｍ－１の範囲に二酸化炭素の吸収ピークが観察されたが、アンモニアの流通後であっても、２３００～２１００ｃｍ－１の範囲にイソシアン酸に基づく吸収ピークが観測されなかった。したがって、本比較例ではイソシアン酸が生成されていないことが判る。
[Comparative Example 1]
A sodium-type zeolite (Na-ZSM-5, manufactured by Tosoh, SiO 2 / Al 2 O 3 mass ratio = 23.8) was ion-exchanged to prepare an NH 4 -type zeolite (NH 4 -ZSM-5). Then, 30 mg of NH 4 -ZSM-5 was tablet-molded to obtain a disk-shaped solid having the same dimensions as in Example 1. This solid matter was placed on the sample table of the diffuse reflector. Then, the temperature is raised from room temperature to 600 ° C. using the temperature controller attached to the sample table, and the solid matter is heat-treated at 600 ° C. for 1 hour under atmospheric atmosphere and atmospheric pressure, and the proton type as a catalyst is used. Zeolite (H-ZSM-5) was obtained. This catalyst has a site (acid point) whose surface is an acid, and no base point is formed.
Next, the temperature of the catalyst was lowered to 300 ° C. and maintained, and carbon dioxide gas at room temperature (25 ° C.) was maintained at 300 ° C. for 10 minutes at a flow rate of 40 mL / min under atmospheric atmosphere and atmospheric pressure. After circulating in the air atmosphere and atmospheric pressure, a mixed gas of 1% by volume ammonia gas / 99% by volume argon gas at room temperature (25 ° C.) was mixed at 10 mL / min (ammonia gas: 0.1 mL / min). It was circulated in a sample table maintained at 300 ° C. for 10 minutes at a flow rate.
In this comparative example, the result of acquiring the IR diffuse reflection spectrum for the catalyst after the reaction is shown in FIG. 7. As shown in the figure, in this comparative example, the absorption peak of carbon dioxide was observed in the range of 2400 to 2300 cm -1 due to the circulation of carbon dioxide, but even after the circulation of ammonia, 2300 to 2100 cm -1 was observed. No absorption peak based on isocyanic acid was observed in the range of. Therefore, it can be seen that isocyanic acid is not produced in this comparative example.
〔触媒のＢＥＴ比表面積測定〕
触媒のＢＥＴ比表面積は、Ｍｏｎｏｓｏｒｂ ＭＳ－２（ユアサアイオニクス製）を用いて、窒素吸着によるＢＥＴ１点法により測定した。その結果、実施例１～４の触媒のＢＥＴ比表面積は９１ｍ２／ｇであり、実施例５の触媒のＢＥＴ比表面積は１６３ｍ２／ｇであり、比較例１の触媒のＢＥＴ比表面積は３２０ｍ２／ｇであった。
[Measurement of BET specific surface area of catalyst]
The BET specific surface area of the catalyst was measured by the BET 1-point method by nitrogen adsorption using Monosorb MS-2 (manufactured by Yuasa Ionics). As a result, the BET specific surface area of the catalysts of Examples 1 to 4 was 91 m 2 / g, the BET specific surface area of the catalyst of Example 5 was 163 m 2 / g, and the BET specific surface area of the catalyst of Comparative Example 1 was 320 m. It was 2 / g.
以上のとおり、各実施例によれば、特別な装置を用意しなくとも、いずれの条件であってもイソシアン酸が低コストで製造できることが判る。特に、反応時において好適な温度条件にて加熱することによって、イソシアン酸に基づく吸収ピーク高さが大きくなり、イソシアン酸の生成量が多くなることも推定される。なお、比較例として示していないが、アンモニアガスに代えて、同流量及び温度条件での窒素ガスを流通させた場合には、２３００～２１００ｃｍ－１の範囲にイソシアン酸に基づく吸収ピークが観測されず、イソシアン酸が生成されないことを本発明者は確認している。
As described above, according to each embodiment, it can be seen that isocyanic acid can be produced at low cost under any condition without preparing a special device. In particular, it is presumed that the absorption peak height based on isocyanic acid increases and the amount of isocyanic acid produced increases by heating under suitable temperature conditions during the reaction. Although not shown as a comparative example, when nitrogen gas is circulated under the same flow rate and temperature conditions instead of ammonia gas, an absorption peak based on isocyanic acid is observed in the range of 2300 to 2100 cm -1 . However, the present inventor has confirmed that isocyanic acid is not produced.
Claims (6)
前記触媒の存在下で、二酸化炭素とアンモニアとを反応させる工程を有する、イソシアン酸の製造方法。 Using a magnesium compound as a catalyst
A method for producing isocyanate, which comprises a step of reacting carbon dioxide with ammonia in the presence of the catalyst.
前記触媒に吸着された二酸化炭素と、アンモニアとを反応させる、請求項１～３のいずれか一項に記載のイソシアン酸の製造方法。 In the step, the catalyst and carbon dioxide are brought into contact with each other to be adsorbed, and then after that,
The method for producing isocyanic acid according to any one of claims 1 to 3, wherein carbon dioxide adsorbed on the catalyst is reacted with ammonia.
The method for producing isocyanate according to claim 5, wherein the step is carried out in a state of being heated to more than 100 ° C. and 600 ° C. or lower.
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS497000B1 (en) * | 1968-12-26 | 1974-02-18 | ||
| JPS54153800A (en) * | 1978-05-25 | 1979-12-04 | Western Electric Co | Manufacture of cyanate compound |
| JPS5869719A (en) * | 1981-09-24 | 1983-04-26 | アメリカン・サイアナミド・カンパニ− | Manufacture of isocyanic acid by hydrogen cyanide heat insulating oxidation |
| JPH06171927A (en) * | 1992-08-13 | 1994-06-21 | Chem Linz Ag | Method of preparing isocyanic acid by decomposition of n, n-disubstituted urea |
| JP2019182705A (en) * | 2018-04-10 | 2019-10-24 | 国立大学法人茨城大学 | Method for generating highly pure isocyanic acid, apparatus for generating, built-in kit, gas-generating device, and method for analyzing |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JPS497000B1 (en) * | 1968-12-26 | 1974-02-18 | ||
| JPS54153800A (en) * | 1978-05-25 | 1979-12-04 | Western Electric Co | Manufacture of cyanate compound |
| JPS5869719A (en) * | 1981-09-24 | 1983-04-26 | アメリカン・サイアナミド・カンパニ− | Manufacture of isocyanic acid by hydrogen cyanide heat insulating oxidation |
| JPH06171927A (en) * | 1992-08-13 | 1994-06-21 | Chem Linz Ag | Method of preparing isocyanic acid by decomposition of n, n-disubstituted urea |
| JP2019182705A (en) * | 2018-04-10 | 2019-10-24 | 国立大学法人茨城大学 | Method for generating highly pure isocyanic acid, apparatus for generating, built-in kit, gas-generating device, and method for analyzing |
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| WANG, MING ET AL.: "Clean and Efficient Transformation of CO2 to Isocyanic Acid: The Important Role of Triatomic Cation", J. PHYS. CHEM. A, vol. 123, no. 27, JPN6022054658, 14 May 2019 (2019-05-14), US, pages 5762 - 5767, ISSN: 0004959168 * |
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