JP2009148728A

JP2009148728A - Catalyst and method for producing methacrylic acid

Info

Publication number: JP2009148728A
Application number: JP2007330809A
Authority: JP
Inventors: Junya Yasukawa; 隼也安川; Masahide Kondo; 正英近藤
Original assignee: Mitsubishi Rayon Co Ltd
Current assignee: Mitsubishi Rayon Co Ltd
Priority date: 2007-12-21
Filing date: 2007-12-21
Publication date: 2009-07-09

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst for producing methacrylic acid stably in high yield by subjecting methacrolein to vapor-phase catalytic oxidation using molecular oxygen. <P>SOLUTION: The catalyst for producing methacrylic acid has the composition shown by formula (1): P<SB>a</SB>Mo<SB>b</SB>V<SB>c</SB>Cu<SB>d</SB>X<SB>e</SB>Y<SB>f</SB>Z<SB>g</SB>O<SB>h</SB>(wherein X is at least one element selected from the group consisting of Sb, Bi, As, Ge, Zr, Te, Se, Si, W and B; Y is at least one element selected from the group consisting of Fe, Zn, Cr, Mg, Ta, Co, Mn, Ba, Ga, Ce and La; Z is at least one element selected from the group consisting of K and Cs; a, b, c, d, e, f, g and h are each an atomic ratio of each element and when b=12, a=0.55-0.8, c=0.01-3, d=0.01-2, e=0-3, f=0-3, g=0.01-3 and h is the atomic ratio of the oxygen, which is required to satisfy the valence of each element). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明はメタクロレインを分子状酸素により気相接触酸化してメタクリル酸を製造するためのメタクリル酸製造用触媒およびこの触媒を用いるメタクリル酸の製造方法に関する。 The present invention relates to a catalyst for producing methacrylic acid for producing methacrylic acid by vapor-phase catalytic oxidation of methacrolein with molecular oxygen and a method for producing methacrylic acid using the catalyst.

従来、メタクロレインを気相接触酸化してメタクリル酸を製造するための触媒として数多くの提案がされている。例えば、特許文献１〜３には、リン、モリブデンおよびアルカリ金属を含有する触媒であって、触媒中のモリブデン対リンおよびアルカリ金属対リンのモル比がそれぞれ１２以下および１．２以下である触媒が例示されている。また、特許文献４には、リン、モリブデン、アルカリ金属および銀を含有し、触媒中のモリブデン対リンおよびアルカリ金属対リンのモル比がそれぞれ２０および１．７である触媒が例示されている。しかしながら、これらの特許文献に提案されている触媒は、更なる触媒性能の向上が望まれている。 Conventionally, many proposals have been made as catalysts for producing methacrylic acid by gas phase catalytic oxidation of methacrolein. For example, in Patent Documents 1 to 3, a catalyst containing phosphorus, molybdenum and an alkali metal, wherein the molar ratio of molybdenum to phosphorus and alkali metal to phosphorus in the catalyst is 12 or less and 1.2 or less, respectively. Is illustrated. Patent Document 4 exemplifies a catalyst containing phosphorus, molybdenum, alkali metal and silver, and having a molar ratio of molybdenum to phosphorus and alkali metal to phosphorus in the catalyst of 20 and 1.7, respectively. However, the catalyst proposed in these patent documents is desired to further improve the catalyst performance.

特開２００５−６６４７６号公報JP 2005-66476 A 特開平１１−２２８４８７号公報JP-A-11-228487 特開平１１−１７９２０９号公報Japanese Patent Laid-Open No. 11-179209 特開２００３−２５１１８８号公報JP 2003-251188 A

本発明は、メタクロレインを分子状酸素により気相接触酸化してメタクリル酸を高収率で製造し得る触媒およびこの触媒を用いるメタクリル酸の製造方法を提供することを目的とする。 An object of the present invention is to provide a catalyst capable of producing methacrylic acid in a high yield by gas phase catalytic oxidation of methacrolein with molecular oxygen and a method for producing methacrylic acid using the catalyst.

本発明の要旨とするところは、メタクロレインを分子状酸素により気相接触酸化してメタクリル酸を製造するための下記式（１）で表される組成を有するメタクリル酸製造用触媒を第一の発明とする。
Ｐ_aＭｏ_bＶ_cＣｕ_dＸ_eＹ_fＺ_gＯ_h （１）
式（１）中、Ｐ、Ｍｏ、Ｖ、ＣｕおよびＯは、それぞれリン、モリブデン、バナジウム、銅および酸素を示し、Ｘはアンチモン、ビスマス、砒素、ゲルマニウム、ジルコニウム、テルル、セレン、ケイ素、タングステンおよびホウ素からなる群より選ばれる少なくとも１種類の元素を示し、Ｙは鉄、亜鉛、クロム、マグネシウム、タンタル、コバルト、マンガン、バリウム、ガリウム、セリウムおよびランタンからなる群より選ばれる少なくとも１種類の元素を示し、Ｚはカリウム、およびセシウムからなる群より選ばれる少なくとも１種類の元素を示す。ａ、ｂ、ｃ、ｄ、ｅ、ｆ、ｇおよびｈは各元素の原子比率を表し、ｂ＝１２のとき、ａ＝０．５５〜０．８、ｃ＝０．０１〜３、ｄ＝０．０１〜２、ｅ＝０〜３、ｆ＝０〜３、ｇ＝０．０１〜３であり、ｈは前記各元素の原子価を満足するのに必要な酸素の原子比率である。
さらに前記式（１）で表される組成を有するメタクリル酸製造用触媒の存在下で、メタクロレインを分子状酸素により気相接触酸化するメタクリル酸の製造方法を第二の発明とする。 The gist of the present invention is that a catalyst for methacrylic acid production having a composition represented by the following formula (1) for producing methacrylic acid by vapor-phase catalytic oxidation of methacrolein with molecular oxygen is the first. Invention.
_{_{_{_{P a Mo b V c Cu d}}}} X e Y f Z g O h (1)
In the formula (1), P, Mo, V, Cu and O represent phosphorus, molybdenum, vanadium, copper and oxygen, respectively, X represents antimony, bismuth, arsenic, germanium, zirconium, tellurium, selenium, silicon, tungsten and Y represents at least one element selected from the group consisting of boron, and Y represents at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, cobalt, manganese, barium, gallium, cerium and lanthanum. Z represents at least one element selected from the group consisting of potassium and cesium. a, b, c, d, e, f, g and h represent the atomic ratio of each element. When b = 12, a = 0.55 to 0.8, c = 0.01 to 3, d = 0.01-2, e = 0-3, f = 0-3, g = 0.01-3, and h is the atomic ratio of oxygen necessary to satisfy the valence of each element.
Furthermore, a method for producing methacrylic acid in which methacrolein is subjected to gas phase catalytic oxidation with molecular oxygen in the presence of a catalyst for producing methacrylic acid having the composition represented by the formula (1) is a second invention.

本発明によれば、メタクロレインを分子状酸素により気相接触酸化してメタクリル酸を高収率で製造することができる。 According to the present invention, methacrolein can be produced in a high yield by subjecting methacrolein to gas phase catalytic oxidation with molecular oxygen.

本発明のメタクリル酸製造用触媒（以下、「触媒」という）は前記式（１）で表される組成を有し、各元素の原子比率として、ｂ＝１２としたとき、ａ＝０．５５〜０．８、ｃ＝０．０１〜３、ｄ＝０．０１〜２、ｅ＝０〜３、ｆ＝０〜３、ｇ＝０．０１〜３の範囲であるときメタクリル酸を高収率で製造できる。
また、本発明の触媒はメタクリル酸を高収率で製造できる点で、前記式（１）において、Ｚ対リンの原子比（ｇ／ａ）は１．６以上が好ましい。 The catalyst for producing methacrylic acid (hereinafter referred to as “catalyst”) of the present invention has a composition represented by the above formula (1), and when the atomic ratio of each element is b = 12, a = 0.55. -0.8, c = 0.01-3, d = 0.01-2, e = 0-3, f = 0-3, and g = 0.01-3. Can be manufactured at a rate.
In addition, in the above formula (1), the atomic ratio (g / a) of Z to phosphorus is preferably 1.6 or more because the catalyst of the present invention can produce methacrylic acid in a high yield.

本発明の触媒を調製する方法としては、成分の著しい偏在を伴わない範囲であれば特に限定されるものではなく、水、アルコール等を溶媒または分散媒として各触媒成分を溶解または分散混合した後に溶媒または分散媒を除去する蒸発乾固法、水、アルコール等を溶媒または分散媒として各触媒成分を溶解または分散混合した液から固形物を沈殿析出させる沈殿法、触媒成分の酸化物を混合する酸化物混合法等従来からよく知られている種々の方法を用いることができる。
上記で得られた固形物は、通常、室温〜１５０℃で乾燥され、その後空気雰囲気下等で約３００〜６００℃で熱処理され、触媒とされる。 The method for preparing the catalyst of the present invention is not particularly limited as long as the components are not significantly unevenly distributed. After each catalyst component is dissolved or dispersed and mixed using water, alcohol or the like as a solvent or dispersion medium. Evaporation to dryness to remove the solvent or dispersion medium, precipitation method to precipitate solids from a solution in which each catalyst component is dissolved or dispersed and mixed with water, alcohol, etc. as the solvent or dispersion medium, and oxides of the catalyst components are mixed Various conventionally well-known methods such as an oxide mixing method can be used.
The solid material obtained above is usually dried at room temperature to 150 ° C., and then heat-treated at about 300 to 600 ° C. in an air atmosphere or the like to be used as a catalyst.

触媒の調製に用いる原料としては特に限定はなく、各元素の硝酸塩、炭酸塩、酢酸塩、アンモニウム塩、酸化物、ハロゲン化物等を組み合わせて使用することができる。モリブデン原料としては、例えば、三酸化モリブデン、モリブデン酸およびパラモリブデン酸アンモニウム、ジモリブデン酸アンモニウム、テトラモリブデン酸アンモニウム等のモリブデン酸アンモニウムが挙げられる。リンの化合物としては、例えば、正リン酸、五酸化リン、およびリン酸アンモニウムが挙げられる。また、バナジウムの化合物としては、例えば、五酸化バナジウムおよびメタバナジン酸アンモニウムが挙げられる。また、リンおよびモリブデン並びにリン、モリブデンおよびバナジウムの化合物としてリンモリブデン酸、モリブドバナドリン酸、リンモリブデン酸アンモニウム等のヘテロポリ酸およびヘテロポリ酸塩を使用することもできる。これらの化合物は、各元素に対して１種を用いても、２種以上を併用してもよい。 The raw material used for preparing the catalyst is not particularly limited, and nitrates, carbonates, acetates, ammonium salts, oxides, halides and the like of each element can be used in combination. Examples of the molybdenum raw material include ammonium molybdate such as molybdenum trioxide, molybdic acid and ammonium paramolybdate, ammonium dimolybdate, and ammonium tetramolybdate. Examples of phosphorus compounds include orthophosphoric acid, phosphorus pentoxide, and ammonium phosphate. Examples of vanadium compounds include vanadium pentoxide and ammonium metavanadate. Moreover, heteropolyacids and heteropolyacid salts such as phosphomolybdic acid, molybdovanadolinic acid and ammonium phosphomolybdate can also be used as the compounds of phosphorus and molybdenum and phosphorus, molybdenum and vanadium. These compounds may use 1 type with respect to each element, or may use 2 or more types together.

本発明の触媒は担体無しで用いてもよいが、シリカ、アルミナ、シリカ・アルミナ、シリコーンカーバイト等の不活性担体に担持させるか、あるいはこれら不活性担体で希釈して用いてもよい。 The catalyst of the present invention may be used without a carrier, but it may be supported on an inert carrier such as silica, alumina, silica-alumina, silicone carbide or the like, or may be diluted with these inert carriers.

本発明の触媒は、反応条件および反応装置を考慮して、粉体状で用いても、あるいは球状、リング状、円柱状、中空状、フレーク状、星形状等に賦形して用いてもよい。
本発明においては、触媒の存在下で、メタクロレインを分子状酸素により気相接触酸化させてメタクリル酸を製造することができる。 The catalyst of the present invention may be used in the form of powder in consideration of the reaction conditions and the reaction apparatus, or may be used after being shaped into a spherical shape, ring shape, cylindrical shape, hollow shape, flake shape, star shape, or the like. Good.
In the present invention, methacrolein can be vapor-phase contact oxidized with molecular oxygen in the presence of a catalyst to produce methacrylic acid.

上記の方法において、反応原料のガス中のメタクロレインの濃度は広い範囲で変えることができるが、１〜２０容量％が好ましく、３〜１０容量％がより好ましい。使用されるメタクロレインは水、低級飽和アルデヒド等のメタクロレインの気相接触酸化反応に実質的な影響を与えない不純物を少量含んでいてもよい。 In the above method, the concentration of methacrolein in the reaction raw material gas can be varied within a wide range, but is preferably 1 to 20% by volume, more preferably 3 to 10% by volume. The methacrolein used may contain a small amount of impurities that do not substantially affect the gas phase catalytic oxidation reaction of methacrolein such as water and lower saturated aldehydes.

分子状酸素としては空気を用いるのが経済的に有利であるが、必要に応じて純酸素で富化した空気を用いてもよい。反応原料のガス中の酸素濃度はメタクロレインに対する酸素のモル比で規定され、そのモル比は０．３〜４が好ましく、０．４〜２．５がより好ましい。反応原料のガスは不活性ガスを加えて希釈してもよい。ここで、不活性ガスとは触媒の反応活性に影響を与えない気体のことをいい、例えば、窒素、水蒸気、二酸化炭素、ヘリウムおよびアルゴン等が挙げられる。 Although it is economically advantageous to use air as molecular oxygen, air enriched with pure oxygen may be used as necessary. The oxygen concentration in the reaction raw material gas is defined by the molar ratio of oxygen to methacrolein, and the molar ratio is preferably 0.3 to 4, more preferably 0.4 to 2.5. The reaction raw material gas may be diluted by adding an inert gas. Here, the inert gas refers to a gas that does not affect the reaction activity of the catalyst, and examples thereof include nitrogen, water vapor, carbon dioxide, helium, and argon.

メタクロレインの気相接触酸化反応の反応圧力は常圧から数気圧までが好ましい。反応温度は２３０〜４５０℃が好ましく、２５０〜４００℃がより好ましい。 The reaction pressure of the gas phase catalytic oxidation reaction of methacrolein is preferably from normal pressure to several atmospheres. The reaction temperature is preferably 230 to 450 ° C, more preferably 250 to 400 ° C.

以下、本発明を実施例および比較例により説明するが、本発明はこれらの実施例に限定されるものではない。なお、実施例および比較例中の「部」は質量部を意味する。 EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention, this invention is not limited to these Examples. In addition, "part" in an Example and a comparative example means a mass part.

実施例および比較例において、触媒の組成は触媒調製用の原料の仕込み量から求めた。またメタクリル酸の製造における反応原料のガスおよび生成物の分析にはガスクロマトグラフィーを用いた。得られた分析結果に基づき、メタクロレインの転化率（以下、「メタクロレイン転化率」という）、生成したメタクリル酸の選択率（以下、「メタクリル酸選択率」という）およびメタクリル酸の単流収率（以下、「メタクリル酸収率」という）を以下の式により求めた。
メタクロレイン転化率（％）＝（Ｂ／Ａ）×１００
メタクリル酸選択率（％）＝（Ｃ／Ｂ）×１００
メタクリル酸収率（％）＝（Ｃ／Ａ）×１００
ここで、Ａは供給したメタクロレインのモル数、Ｂは反応したメタクロレインのモル数およびＣは生成したメタクリル酸のモル数である。 In the examples and comparative examples, the composition of the catalyst was determined from the amount of the raw material for catalyst preparation. In addition, gas chromatography was used for analysis of reaction raw material gas and products in the production of methacrylic acid. Based on the analysis results obtained, the methacrolein conversion rate (hereinafter referred to as “methacrolein conversion rate”), the selectivity of the produced methacrylic acid (hereinafter referred to as “methacrylic acid selectivity”), and the single flow rate of methacrylic acid. The rate (hereinafter referred to as “methacrylic acid yield”) was determined by the following equation.
Conversion rate of methacrolein (%) = (B / A) × 100
Methacrylic acid selectivity (%) = (C / B) × 100
Methacrylic acid yield (%) = (C / A) × 100
Here, A is the number of moles of methacrolein supplied, B is the number of moles of reacted methacrolein, and C is the number of moles of methacrylic acid produced.

（実施例１）
三酸化モリブデン１３０部を攪拌状態の純水３００部に分散させた。この分散液を攪拌しながらメタバナジン酸アンモニウム３．５２部を加え、さらに純度８５質量％のリン酸６．６７部を加えて９５℃に昇温し、２時間攪拌を続けた。得られたスラリーを５０℃に降温し、純度６０質量％のヒ酸８．２２部を加え、さらに硝酸セシウム１１．２８部を純水２５部に溶解させた水溶液を加えて攪拌した。続いてこのスラリーを７０℃に昇温し、２８質量％アンモニア水３６．２８部を加えて１．５時間攪拌を続け、得られたスラリーに、硝酸銅１．４部を純水１５部に溶解させた水溶液と硝酸鉄１．１７部を純水１５部に溶解させた水溶液を加えた後、撹拌しながら蒸発乾固した。得られた固形物を１３０℃で１６時間乾燥後、加圧成型し、空気流通下、３８０℃で５時間熱処理し、触媒（１）を得た。 Example 1
130 parts of molybdenum trioxide was dispersed in 300 parts of stirred pure water. While stirring this dispersion, 3.52 parts of ammonium metavanadate was added, and 6.67 parts of phosphoric acid having a purity of 85% by mass was added, the temperature was raised to 95 ° C., and stirring was continued for 2 hours. The obtained slurry was cooled to 50 ° C., 8.22 parts of arsenic acid having a purity of 60% by mass was added, and an aqueous solution in which 11.28 parts of cesium nitrate was dissolved in 25 parts of pure water was added and stirred. Subsequently, the slurry was heated to 70 ° C., 36.28 parts of 28 mass% ammonia water was added and stirring was continued for 1.5 hours, and 1.4 parts of copper nitrate was added to 15 parts of pure water. A dissolved aqueous solution and an aqueous solution in which 1.17 parts of iron nitrate were dissolved in 15 parts of pure water were added and then evaporated to dryness with stirring. The obtained solid was dried at 130 ° C. for 16 hours, then pressure-molded, and heat-treated at 380 ° C. for 5 hours under air flow to obtain catalyst (1).

得られた触媒（１）の酸素以外の元素の組成は、Ｍｏ_１５．６Ｐ_１Ｖ_０.５２Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_１．０あった。
触媒（１）を反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of elements other than oxygen in the obtained catalyst (1) was Mo _15.6 P ₁ V _0.52 Cu _0.1 Fe _0.05 As _0.6 Cs _1.0 .
The catalyst (1) is filled in a reaction tube, and a reaction is performed by flowing a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. Went. The product was collected and analyzed by gas chromatography. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（実施例２）
三酸化モリブデンを１５０部およびメタバナジン酸アンモニウムを２．７１部使用したこと以外は実施例１と同様にして、触媒（２）を得た。 (Example 2)
A catalyst (2) was obtained in the same manner as in Example 1 except that 150 parts of molybdenum trioxide and 2.71 parts of ammonium metavanadate were used.

得られた触媒（２）の酸素以外の元素の組成は、Ｍｏ_1８．０Ｐ₁Ｖ_０．４Ｃｕ_０.１Ｆｅ_０.０５Ａｓ_０．６Ｃｓ_１．０であった。
触媒（２）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of elements other than oxygen in the obtained catalyst (2) was Mo _18.0 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _1.0 .
The catalyst (2) is charged into the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen is allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. Reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（実施例３）
三酸化モリブデンを１８０部使用したこと以外は実施例２と同様にして、触媒（３）を得た。 (Example 3)
A catalyst (3) was obtained in the same manner as in Example 2 except that 180 parts of molybdenum trioxide was used.

得られた触媒（３）の酸素以外の元素の組成は、Ｍｏ_２１．６Ｐ₁Ｖ_０．４Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_１．０であった。
触媒（３）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of elements other than oxygen in the obtained catalyst (3) was Mo _21.6 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _1.0 .
The catalyst (3) is filled in the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen is allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. Reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（実施例４）
硝酸セシウム１８．０５部を純水４０部に溶解させた水溶液を使用したこと以外は実施例３と同様にして、触媒（４）を得た。 Example 4
A catalyst (4) was obtained in the same manner as in Example 3 except that an aqueous solution in which 18.05 parts of cesium nitrate was dissolved in 40 parts of pure water was used.

得られた触媒（４）の酸素以外の元素の組成は、Ｍｏ_２１．６Ｐ₁Ｖ_０．４Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_１．６であった。
触媒（４）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of elements other than oxygen in the obtained catalyst (4) was Mo _21.6 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _1.6 .
The catalyst (4) is filled in the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen is allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. Reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（実施例５）
硝酸セシウム３３．８４部を純水７５部に溶解させた水溶液を使用したこと以外は実施例４と同様にして、触媒（５）を得た。 (Example 5)
A catalyst (5) was obtained in the same manner as in Example 4 except that an aqueous solution in which 33.84 parts of cesium nitrate was dissolved in 75 parts of pure water was used.

得られた触媒（５）の酸素以外の元素の組成は、Ｍｏ_２１．６Ｐ₁Ｖ_０．４Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_３．０であった。
触媒（５）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of elements other than oxygen in the obtained catalyst (5) was Mo _21.6 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _3.0 .
The catalyst (5) was filled in the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen was allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. Reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（比較例１）
三酸化モリブデン１００部を使用したこと以外は実施例２と同様にして、比較触媒（Ａ）を得た。 (Comparative Example 1)
A comparative catalyst (A) was obtained in the same manner as in Example 2 except that 100 parts of molybdenum trioxide was used.

得られた比較触媒（Ａ）の酸素以外の元素の組成は、Ｍｏ_１２．０Ｐ₁Ｖ_０．４Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_１．０であった。
比較触媒（Ａ）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of the element other than oxygen in the obtained comparative catalyst (A) was Mo _12.0 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _1.0 .
The comparative catalyst (A) is filled in the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen is allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. The reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（比較例２）
三酸化モリブデン１００部を使用したこと以外は実施例４と同様にして、比較触媒（Ｂ）を得た。 (Comparative Example 2)
A comparative catalyst (B) was obtained in the same manner as in Example 4 except that 100 parts of molybdenum trioxide was used.

得られた比較触媒（Ｂ）の酸素以外の元素の組成は、Ｍｏ_１２．０Ｐ₁Ｖ_０．４Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_１．６であった。
比較触媒（Ｂ）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 The composition of the elements other than oxygen in the obtained comparative catalyst (B) was Mo _12.0 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _1.6 .
The comparative catalyst (B) is filled in the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen is allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. The reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

（比較例３）
三酸化モリブデン１００部を使用したこと以外は実施例５と同様にして、比較触媒（Ｃ）を得た。 (Comparative Example 3)
A comparative catalyst (C) was obtained in the same manner as in Example 5 except that 100 parts of molybdenum trioxide was used.

得られた比較触媒（Ｃ）の酸素以外の元素の組成は、Ｍｏ_１２．０Ｐ₁Ｖ_０．４Ｃｕ_０．１Ｆｅ_０．０５Ａｓ_０．６Ｃｓ_３．０であった。
比較触媒（Ｃ）を前記反応管に充填し、メタクロレイン５容量％、酸素１０容量％、水蒸気２０容量％および窒素６５容量％の混合ガスを反応温度２８０℃および接触時間３．６秒で流して反応を行った。生成物を捕集し、ガスクロマトグラフィーで実施例１と同様に分析した。メタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率の結果を表１に示す。 Composition of elements other than oxygen of the obtained comparative catalyst (C) was Mo _12.0 P ₁ V _0.4 Cu _0.1 Fe _0.05 As _0.6 Cs _3.0 .
The comparative catalyst (C) is filled in the reaction tube, and a mixed gas of 5% by volume of methacrolein, 10% by volume of oxygen, 20% by volume of water vapor and 65% by volume of nitrogen is allowed to flow at a reaction temperature of 280 ° C. and a contact time of 3.6 seconds. The reaction was performed. The product was collected and analyzed by gas chromatography as in Example 1. The results of methacrolein conversion, methacrylic acid selectivity and methacrylic acid yield are shown in Table 1.

実施例１〜５および比較例１〜３のメタクロレイン転化率、メタクリル酸選択率およびメタクリル酸収率を一括して表１に示す。 Table 1 collectively shows the methacrolein conversion rate, methacrylic acid selectivity, and methacrylic acid yield of Examples 1 to 5 and Comparative Examples 1 to 3.

Claims

A catalyst for methacrylic acid production having a composition represented by the following formula (1) for producing methacrylic acid by vapor-phase catalytic oxidation of methacrolein with molecular oxygen.
_{_{_{_{P a Mo b V c Cu d}}}} X e Y f Z g O h (1)
(In the formula (1), P, Mo, V, Cu and O represent phosphorus, molybdenum, vanadium, copper and oxygen, respectively, and X represents antimony, bismuth, arsenic, germanium, zirconium, tellurium, selenium, silicon and tungsten. And at least one element selected from the group consisting of boron and Y, at least one element selected from the group consisting of iron, zinc, chromium, magnesium, tantalum, cobalt, manganese, barium, gallium, cerium and lanthanum Z represents at least one element selected from the group consisting of potassium and cesium, a, b, c, d, e, f, g, and h represent the atomic ratio of each element, and b = 12 Where a = 0.55-0.8, c = 0.01-3, d = 0.01-2, e = 0-3, f = 0-3, g = 0 Is from 01 to 3, h is an atomic ratio of oxygen required to satisfy the valence of each element.)

The catalyst according to claim 1, wherein the atomic ratio (g / a) of Z to phosphorus is 1.6 or more.

A method for producing methacrylic acid, comprising subjecting methacrolein to gas phase catalytic oxidation with molecular oxygen in the presence of the catalyst for producing methacrylic acid according to claim 1 or 2.