JP6033027B2

JP6033027B2 - Method for producing catalyst for producing unsaturated aldehyde and unsaturated carboxylic acid, catalyst therefor, and method for producing unsaturated aldehyde and unsaturated carboxylic acid

Info

Publication number: JP6033027B2
Application number: JP2012216765A
Authority: JP
Inventors: 友厚河野; 安孝竹本; 直広福本; 谷本　道雄; 道雄谷本; 秀夫小野寺
Original assignee: Nippon Shokubai Co Ltd
Current assignee: Nippon Shokubai Co Ltd
Priority date: 2012-09-28
Filing date: 2012-09-28
Publication date: 2016-11-30
Anticipated expiration: 2032-09-28
Also published as: JP2014069128A

Description

本発明はプロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルからなる群より選ばれる少なくとも一種の化合物を、分子状酸素または分子状酸素含有ガスの存在下で接触気相酸化することにより、対応する不飽和アルデヒドおよび不飽和カルボン酸を製造するための複合酸化物触媒の製造方法とその製造方法によって得られた触媒、ならびにその触媒を用いる不飽和アルデヒドおよび不飽和カルボン酸の製造方法に関する。 The present invention performs catalytic gas phase oxidation of at least one compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether in the presence of molecular oxygen or a molecular oxygen-containing gas. The present invention relates to a method for producing a composite oxide catalyst for producing a corresponding unsaturated aldehyde and unsaturated carboxylic acid, a catalyst obtained by the method, and a method for producing unsaturated aldehyde and unsaturated carboxylic acid using the catalyst.

プロピレン、イソブチレン、ｔ−ブチルアルコールまたはメチル−ｔ−ブチルエーテルの気相接触酸化反応により対応する不飽和アルデヒドおよび不飽和カルボン酸を効率よく製造するための触媒に関して種々の製造方法が提案されている。その大部分はモリブデンおよびビスマスを主成分とするモリブデン−ビスマス系触媒である。 Various production methods have been proposed for catalysts for efficiently producing the corresponding unsaturated aldehydes and unsaturated carboxylic acids by the gas phase catalytic oxidation reaction of propylene, isobutylene, t-butyl alcohol or methyl-t-butyl ether. Most of them are molybdenum-bismuth catalysts mainly composed of molybdenum and bismuth.

たとえば、特許文献１には、複合酸化物触媒を、各成分元素の供給源化合物の水性系での一体化及び加熱を含む工程を経て製造する方法において、モリブデン、鉄、ニッケル又はコバルトの少なくとも一つ、及びシリカを含む原料塩水溶液又はこれを乾燥して得た乾燥物を加熱処理して触媒前駆体を製造する前工程、該触媒前駆体、モリブデン及びビスマス化合物とを水性溶媒とともに一体化し、乾燥、焼成する後工程を経て調製することを特徴とする複合酸化物触媒の製造方法が開示されている。特許文献２には、モリブデン、ビスマスおよび鉄を必須成分とする原料塩水溶液または水性スラリーを加熱処理して得られる触媒前駆体の減量率を調節することで活性、選択率および機械強度に優れた不飽和アルデヒドおよび／または不飽和カルボン酸合成用触媒を再現性よく製造するために好適な触媒の製造方法が開示されている。特許文献３には、該気相接触酸化の反応活性が異なる少なくともモリブデン、ビスマスおよび鉄を含む２種類以上の触媒粉を混合し、成形することを特徴とする不飽和アルデヒドおよび不飽和カルボン酸合成用触媒の製造方法が開示されている。 For example, in Patent Document 1, in a method for producing a composite oxide catalyst through a process including integration and heating of a source compound of each component element in an aqueous system, at least one of molybdenum, iron, nickel, or cobalt is disclosed. And a pre-process for producing a catalyst precursor by heat-treating a raw salt aqueous solution containing silica or a dried product obtained by drying the silica, integrating the catalyst precursor, molybdenum and a bismuth compound together with an aqueous solvent, There is disclosed a method for producing a composite oxide catalyst characterized by being prepared through a post-process of drying and firing. Patent Document 2 is excellent in activity, selectivity and mechanical strength by adjusting the weight loss rate of a catalyst precursor obtained by heat treatment of an aqueous raw salt solution or aqueous slurry containing molybdenum, bismuth and iron as essential components. A method for producing a catalyst suitable for reproducibly producing an unsaturated aldehyde and / or unsaturated carboxylic acid synthesis catalyst is disclosed. Patent Document 3 discloses the synthesis of an unsaturated aldehyde and an unsaturated carboxylic acid characterized in that two or more kinds of catalyst powders containing at least molybdenum, bismuth and iron having different reaction activities of gas phase catalytic oxidation are mixed and molded. A method for producing a catalyst is disclosed.

特開２００３−２２０３３５号公報JP 2003-220335 A 特開２００３−２５１１８３号公報JP 2003-251183 A 特開２００４−１３０２６１号公報JP 2004-130261 A

プロピレン、イソブチレン、ｔ−ブチルアルコールまたはメチル−ｔ−ブチルエーテルの気相接触酸化反応により対応する不飽和アルデヒドおよび不飽和カルボン酸を効率よく製造するための触媒は、工業的規模で製造した際の触媒活性、選択性などの触媒性能面において、触媒の製造方法による更なる改良が望まれている。 The catalyst for efficiently producing the corresponding unsaturated aldehyde and unsaturated carboxylic acid by the gas phase catalytic oxidation reaction of propylene, isobutylene, t-butyl alcohol or methyl-t-butyl ether is a catalyst produced on an industrial scale. Further improvements in catalyst performance such as activity and selectivity are desired by the catalyst production method.

工業的規模でアクロレインやメタクロレインのような不飽和アルデヒドを製造するには、数トンから数十トンという多量の触媒が充填された酸化反応器が使用される。一方、酸化反応に使用する触媒の製造量は、通常１回の製造（１ロット）につき数百ｋｇ〜数ｔ程度であるため、一つの酸化反応器に充填するためには複数ロットの触媒を製造する必要がある。製造ロット数が増すと、触媒製造中の各工程における条件の振れなどに起因する製造ロット間での触媒性能の再現性が低下する可能性がある。一方、製造ロット数を減らすために１回の製造スケールを大きくすると、同一製造ロット内での条件のバラつきが生じやすく、触媒全体の性能が低位になってしまうといった問題があった。 In order to produce unsaturated aldehydes such as acrolein and methacrolein on an industrial scale, an oxidation reactor packed with a large amount of catalyst of several tons to tens of tons is used. On the other hand, the production amount of the catalyst used for the oxidation reaction is usually about several hundred kg to several t per one production (one lot). Therefore, in order to fill one oxidation reactor, a plurality of lots of catalysts are used. It needs to be manufactured. When the number of production lots increases, the reproducibility of the catalyst performance between production lots due to fluctuations in conditions in each step during catalyst production may decrease. On the other hand, if the production scale is increased once in order to reduce the number of production lots, there is a problem that the conditions within the same production lot are likely to vary and the performance of the entire catalyst is lowered.

本発明の目的は、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルなどを、分子状酸素または分子状酸素含有ガスを用い接触気相酸化して、対応する不飽和アルデヒドおよび不飽和カルボン酸を製造するための触媒であって、機械的強度、触媒活性および収率が優れた触媒の安定した製造方法を提供することである。本発明の別の目的は、その製造方法で製造された触媒活性および収率が優れた触媒、ならびに該触媒の存在下に、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルから選ばれる少なくとも一種の化合物を、分子状酸素または分子状酸素含有ガスにより接触気相酸化して、対応する不飽和アルデヒドおよび不飽和カルボン酸を長期間安定して高収率で製造する方法を提供することである。 The object of the present invention is to catalytically vapor-oxidize propylene, isobutylene, t-butyl alcohol, methyl-t-butyl ether and the like using molecular oxygen or a molecular oxygen-containing gas to produce the corresponding unsaturated aldehyde and unsaturated carboxylic acid. The present invention provides a stable production method of a catalyst for producing an acid, which is excellent in mechanical strength, catalytic activity and yield. Another object of the present invention is selected from propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether in the presence of the catalyst having excellent catalytic activity and yield produced by the production method and the catalyst. To provide a method for stably producing a corresponding unsaturated aldehyde and unsaturated carboxylic acid for a long period of time in a high yield by catalytic vapor phase oxidation of at least one compound with molecular oxygen or a molecular oxygen-containing gas. It is.

本発明者は、かかる課題を解決するべく、触媒の各製造工程を詳細に鋭意検討した結果、大きなスケールで製造すると、触媒性能にばらつきが出やすい工程部分のスケールを小さくして、必要に応じて処理条件を変更することにより、機械的強度に優れ、長期間安定して高い活性および選択性を示す触媒が再現性よく製造できることを見出した。すなわち、触媒の製造工程として、触媒成分元素の出発原料を混合する原料混合工程、得られた出発原料混合物等を加熱処理し乾燥物を得る乾燥工程、得られた乾燥物を粉砕する粉砕工程、得られた粉砕物を成形する成形工程、および、得られた成形体を焼成する焼成工程を含む不飽和アルデヒドおよび不飽和カルボン酸製造用複合酸化物触媒の製造方法において、触媒性能にばらつきが出やすい乾燥工程、粉砕工程、成形工程、焼成工程の各工程で処理される出発原料混合物、乾燥物、粉砕物または成形体の少なくとも一つを２以上に分割して処理することで、機械的強度に優れ、長期間安定して高い活性および選択性を示す触媒が再現性よく製造できることを見出し本発明に至った。
また本発明は、上記方法にて製造された不飽和アルデヒドおよび不飽和カルボン酸製造用複合酸化物触媒である。
さらに本発明は、上記の複合酸化物触媒を用い、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルからなる群より選ばれる少なくとも一種の原料化合物の含有ガスを、分子状酸素または分子状酸素含有ガスの存在下で接触気相酸化する不飽和アルデヒドおよび不飽和カルボン酸の製造方法である。 As a result of detailed investigations of the catalyst production processes in detail in order to solve such problems, the present inventor has reduced the scale of the process part where the catalyst performance tends to vary when manufactured on a large scale, and if necessary, By changing the treatment conditions, it has been found that a catalyst having excellent mechanical strength, stable and long-term activity and selectivity can be produced with good reproducibility. That is, as a production process of the catalyst, a raw material mixing step of mixing the starting raw materials of the catalyst component elements, a drying step of heat-treating the obtained starting raw material mixture and the like to obtain a dried product, a pulverizing step of pulverizing the obtained dried product, In the method for producing a composite oxide catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid, comprising a forming step for forming the obtained pulverized product and a firing step for firing the obtained molded product, the catalyst performance varies. Mechanical strength is achieved by dividing at least one of the starting material mixture, dried product, pulverized product or molded product that is processed in each of the easy drying process, pulverizing process, molding process, and firing process into two or more. Thus, the inventors have found that a catalyst exhibiting excellent activity and selectivity stably for a long period of time can be produced with good reproducibility, leading to the present invention.
Moreover, this invention is the complex oxide catalyst for unsaturated aldehyde and unsaturated carboxylic acid manufacture which were manufactured by the said method.
Furthermore, the present invention uses the complex oxide catalyst described above, and contains a gas containing at least one raw material compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether, as molecular oxygen or molecular A process for producing unsaturated aldehydes and unsaturated carboxylic acids that undergo catalytic gas phase oxidation in the presence of an oxygen-containing gas.

本発明によれば、工業的規模において、機械的強度、活性および収率が優れた不飽和アルデヒドおよび不飽和カルボン酸合成用複合酸化物触媒を再現性よく製造することができ、その結果、高価な触媒の製造時のロスが大幅に削減できる。また、得られた触媒を用いて、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルなどを、分子状酸素または分子状酸素含有ガスにより気相接触酸化することにより、それぞれ対応する不飽和アルデヒドおよび不飽和カルボン酸を長期間安定して高収率で製造することができる。 According to the present invention, an unsaturated aldehyde and a composite oxide catalyst for synthesizing an unsaturated carboxylic acid having excellent mechanical strength, activity and yield can be produced with good reproducibility on an industrial scale. Loss during the production of a simple catalyst can be greatly reduced. Further, using the obtained catalyst, propylene, isobutylene, t-butyl alcohol, methyl-t-butyl ether, and the like are subjected to gas phase catalytic oxidation with molecular oxygen or a molecular oxygen-containing gas, thereby corresponding to the corresponding unsaturated compounds. Aldehydes and unsaturated carboxylic acids can be produced stably in a high yield for a long period of time.

以下、本発明について詳細に説明するが、本発明の範囲は以下の説明内容には制限されず、本発明の趣旨を損なわない範囲で適宜変更し実施することができる。 Hereinafter, the present invention will be described in detail. However, the scope of the present invention is not limited to the following description, and can be appropriately modified and implemented without departing from the spirit of the present invention.

本発明にかかる不飽和アルデヒドおよび不飽和カルボン酸合成用複合酸化物触媒の製造方法は、触媒成分元素の出発原料を混合する原料混合工程、得られた出発原料混合物等を加熱処理する乾燥工程、得られた乾燥物を粉砕する粉砕工程、得られた粉砕物を成形する成形工程、および、得られた成形体を焼成する焼成工程を含み、これら各工程のうち、乾燥工程、粉砕工程、成形工程または焼成工程の少なくとも一つの工程で、当該工程で処理に供される出発原料混合物、乾燥物、触媒前駆体または成形体の少なくとも一つを２以上に分割して処理することで達成される。また、乾燥工程、粉砕工程、成形工程および焼成工程の全ての工程を２分割して処理することでも達成されることは言うまでもない。
（１）原料混合工程
本発明において原料混合工程とは、不飽和アルデヒドおよび不飽和カルボン酸製造用触媒の各構成成分元素を単独あるいは複数含む出発原料を混合し、全ての触媒成分元素を含む出発原料混合物を得る工程である。 The method for producing a composite oxide catalyst for synthesizing an unsaturated aldehyde and unsaturated carboxylic acid according to the present invention includes a raw material mixing step of mixing starting materials of catalyst component elements, a drying step of heat-treating the obtained starting raw material mixture, etc. Including a pulverization step for pulverizing the obtained dried product, a molding step for molding the obtained pulverized product, and a firing step for firing the obtained molded body, and among these steps, the drying step, the pulverization step, and the molding This is achieved by dividing at least one of the starting raw material mixture, dried product, catalyst precursor or molded body to be processed in the step or at least one step of the calcination step into two or more. . Further, it goes without saying that all the processes of the drying process, the pulverizing process, the molding process, and the baking process are divided into two and processed.
(1) Raw material mixing step In the present invention, the raw material mixing step refers to a starting material containing all catalyst component elements by mixing a single starting material containing one or more constituent elements of the unsaturated aldehyde and unsaturated carboxylic acid production catalyst. This is a step of obtaining a raw material mixture.

本発明で使用することができる触媒成分元素の出発原料については特段の制限はなく、一般にこの種の触媒に使用される金属元素の酸化物、水酸化物、アンモニウム塩、硝酸塩、炭酸塩、硫酸塩、塩化物、有機酸塩などの塩類や、それらの水溶液、ゾルなど、あるいは、これらの混合物を組み合わせて用いることができる。中でも、アンモニウム塩や硝酸塩が好適に用いられる。 There are no particular restrictions on the starting materials of the catalyst component elements that can be used in the present invention, and generally oxides, hydroxides, ammonium salts, nitrates, carbonates, sulfuric acids of metal elements used in this type of catalyst. A salt such as a salt, chloride, or organic acid salt, an aqueous solution or sol thereof, or a mixture thereof can be used. Of these, ammonium salts and nitrates are preferably used.

出発原料混合物は、この種の触媒に一般に用いられている方法により調製すればよく、上記出発原料の各々を水などの溶媒に溶解あるいは懸濁させて溶液あるいはスラリーとし、これらを順次混合すればよい。また、一つの出発原料を複数の溶液あるいはスラリーとし分割して混合することもできる。出発原料の混合条件（混合順序、温度、圧力、ｐＨ等）については特に制限はない。続く乾燥工程における乾燥方法に適用させるように、得られた溶液あるいはスラリーを必要に応じ濃縮しケーキ状物質としてもよい。
（２）乾燥工程
本発明における乾燥工程とは、原料混合工程で得られた出発原料混合物、後述の粉砕工程で得られた粉砕物または後述の成形工程で得られた成形物の少なくとも一つを１００℃〜３００℃の範囲の温度で加熱処理する工程である。 The starting material mixture may be prepared by a method generally used for this type of catalyst. Each of the above starting materials is dissolved or suspended in a solvent such as water to form a solution or slurry, and these are sequentially mixed. Good. One starting material can be divided into a plurality of solutions or slurries and mixed. There are no particular restrictions on the starting material mixing conditions (mixing order, temperature, pressure, pH, etc.). The obtained solution or slurry may be concentrated as necessary to obtain a cake-like substance so as to be applied to the drying method in the subsequent drying step.
(2) Drying step The drying step in the present invention means at least one of the starting raw material mixture obtained in the raw material mixing step, the pulverized material obtained in the pulverization step described later, or the molded product obtained in the molding step described later. In this step, the heat treatment is performed at a temperature in the range of 100 ° C to 300 ° C.

原料混合工程で得られた出発原料混合物を加熱処理し乾燥物を得る乾燥工程においては、続く粉砕工程において粉砕可能な乾燥物が得られる方法であればよい。乾燥物を得るための加熱処理方法には特に限定はなく、出発原料混合物の形態に適用させるように適宜選択できる。例えば、出発原料混合物が溶液状またはスラリー状の場合、スプレードライヤー、ドラムドライヤー等を用いて顆粒状あるいは粉末状の乾燥物を得てもよいし、溶液やスラリーをバットなどに入れて箱型乾燥機で乾燥してもよい。出発原料混合物が溶液またはスラリーを濃縮して得られるケーキ状の場合は、箱型乾燥機、トンネル型乾燥機等を用いて、空気気流中や、窒素などの不活性ガス気流中など気体流通下あるいは雰囲気下で加熱処理してブロック状またはフレーク状の乾燥物を得てもよい。 In the drying process which heat-processes the starting raw material mixture obtained at the raw material mixing process, and obtains a dried material, what is necessary is just a method that can obtain a pulverized dry substance in the subsequent pulverization process. There is no particular limitation on the heat treatment method for obtaining the dried product, and it can be appropriately selected so as to be applied to the form of the starting material mixture. For example, when the starting material mixture is in the form of a solution or a slurry, a granular or powdery dried product may be obtained using a spray dryer, drum dryer or the like, or the solution or slurry is placed in a vat and box-shaped dried You may dry with a machine. When the starting material mixture is in the form of a cake obtained by concentrating the solution or slurry, use a box dryer, tunnel dryer, etc. in a gas stream such as in an air stream or in an inert gas stream such as nitrogen. Or you may heat-process in atmosphere and may obtain a block-shaped or flake-shaped dried material.

また、後述の粉砕工程で得られた粉砕物または後述の成形工程で得られた成形物を加熱処理する場合には、箱型乾燥機、トンネル型乾燥機等を用いて、空気気流中や、窒素などの不活性ガス気流中など気体流通下あるいは雰囲気下で加熱処理して乾燥物とすることができる。 In addition, when heat-treating the pulverized product obtained in the pulverization step described later or the molded product obtained in the molding step described later, using a box-type dryer, a tunnel-type dryer, etc. Heat treatment can be performed under a gas flow or atmosphere such as in an inert gas stream such as nitrogen to obtain a dry product.

出発原料混合物や粉砕物または成形物を２以上に分割して乾燥を行う方法としては、乾燥方法を変えて乾燥する方法、装置を変えて乾燥する方法、同じ装置で２回以上に分けて乾燥する方法などが採用できる。また、その際、乾燥条件を適宜変更し乾燥を行うこともできる。
たとえば、出発原料混合物を２分割して加熱処理する場合は、各々を、スプレードライヤーとドラムドライヤーとの組み合わせ、スプレードライヤーと箱型乾燥機との組み合わせ、あるいは、箱型乾燥機とトンネル型乾燥機との組み合わせ、等の様に異なる処理装置で乾燥する方法が採用できる。また、同じ種類の処理装置を二つ用意し、出発原料混合物を２分割してそれぞれ個別に加熱処理する方法や、一つの処理装置で、２分割した出発原料混合物をそれぞれ個別に加熱処理する方法が採用できる。その際、それぞれ異なる乾燥条件で乾燥してもよく、スプレードライヤーやドラムドライヤーなどで乾燥する場合、連続的に乾燥を行い、途中で乾燥条件を変更する方法でもよい。
乾燥処理に供する出発原料混合物や粉砕物または成形物を２以上に分割して乾燥を行う場合は、そのうちの少なくとも一つを１９０℃未満の温度および／または１００Ｌ／分（固形分重量１ｋｇあたり）の風量下で熱処理することが好ましい。
出発原料混合物を２以上に分割して乾燥を行った場合は、続く粉砕工程に先んじて、それらの乾燥物を混合するか、粉砕工程で乾燥物を混合しながら粉砕する。
（３）粉砕工程
本発明における粉砕工程とは、出発原料混合物の加熱処理により得られた乾燥物を粉砕する工程である。 The method of drying by dividing the starting material mixture, pulverized product or molded product into two or more is the method of drying by changing the drying method, the method of drying by changing the device, or the drying by dividing into two or more times in the same device. The method to do can be adopted. At that time, drying can be performed by appropriately changing the drying conditions.
For example, when the starting material mixture is divided into two parts and subjected to heat treatment, each is a combination of a spray dryer and a drum dryer, a combination of a spray dryer and a box dryer, or a box dryer and a tunnel dryer. A method of drying with a different processing apparatus such as a combination with the above can be adopted. Also, two processing devices of the same type are prepared, and the starting raw material mixture is divided into two parts and individually heated, or the starting raw material mixture divided into two parts is individually heated with one processing device. Can be adopted. In that case, you may dry on different drying conditions, and when drying with a spray dryer, a drum dryer, etc., the method of drying continuously and changing a drying condition in the middle may be used.
When the starting material mixture, pulverized product or molded product to be subjected to the drying treatment is divided into two or more and dried, at least one of them is at a temperature of less than 190 ° C. and / or 100 L / min (per 1 kg of solid content weight) It is preferable to perform the heat treatment under the air flow.
When the starting material mixture is divided into two or more and dried, these dried products are mixed prior to the subsequent pulverization step, or pulverized while mixing the dried product in the pulverization step.
(3) Pulverization step The pulverization step in the present invention is a step of pulverizing a dried product obtained by heat treatment of the starting raw material mixture.

粉砕工程においては、粉砕方法に特に限定はなく、乾燥物の形態に適用させるように選べばよい。例えば各種ハンマーミル、ジェットミル、ボールミル等を用いて乾燥物を粉砕し、続く成形工程において所望の粒子径を有する粉砕物を得ればよい。 In the pulverization step, the pulverization method is not particularly limited, and may be selected so as to be applied in the form of a dried product. For example, the dried product may be pulverized using various hammer mills, jet mills, ball mills, etc., and a pulverized product having a desired particle size may be obtained in the subsequent molding step.

乾燥物を２以上に分割して粉砕を行う場合は、粉砕装置を変えて粉砕する、同じ装置を二つ以上用意して粉砕する、同じ装置で２回以上に分けて粉砕する方法などが採用できる。
分割した乾燥物の形態が異なる場合は、粉砕条件を適宜変更し粉砕を行うことができる。たとえば、２分割した乾燥物が、サイズが異なる顆粒状物質の場合、粉砕機の種類、粉砕時間等の各条件を変更して粉砕してもよい。また、一つの粉砕装置を用いて連続的に粉砕を行い、途中で粉砕条件を変更して粉砕することもできる。 When pulverizing by dividing the dried product into two or more, a method of pulverizing by changing the pulverizing device, preparing two or more of the same devices, pulverizing in two or more times with the same device is adopted it can.
When the divided dried products have different forms, the pulverization can be performed by appropriately changing the pulverization conditions. For example, when the dried product divided into two is a granular material having a different size, it may be pulverized by changing various conditions such as the type of pulverizer and pulverization time. Moreover, it can also grind | pulverize continuously by using one grinder and changing a grinding condition on the way.

また、乾燥物を２以上に分割して粉砕を行う場合は、乾燥物の少なくとも一つを粒度５０〜１５０μｍの範囲となるまで粉砕することが好ましい。 Moreover, when grind | pulverizing by dividing a dried material into 2 or more, it is preferable to grind | pulverize at least one of the dried material until it becomes the range of the particle size of 50-150 micrometers.

さらに粉砕後に乾燥してもよく、その際２以上に分割して乾燥してもよい。 Further, it may be dried after pulverization, and in that case, it may be divided into two or more and dried.

出発原料混合物の加熱処理により得られた乾燥物を２以上に分割して粉砕を行った場合は、続く成形工程に先んじて、それらの粉砕物を混合する。
（４）成形工程
本発明における成形工程とは、粉砕工程で得られた粉砕物あるいは粉砕物を再度乾燥した乾燥物を触媒前駆体として一定の形状に成形、あるいは、一定の形状を有する不活性担体に担持する工程である。 When the dried product obtained by the heat treatment of the starting raw material mixture is divided into two or more and pulverized, these pulverized products are mixed prior to the subsequent molding step.
(4) Molding step The molding step in the present invention is a pulverized product obtained in the pulverization step or a dried product obtained by drying the pulverized product again to form the catalyst precursor into a certain shape, or an inert material having a certain shape. This is a step of supporting the carrier.

触媒の成形方法としては、前記触媒前駆体を押し出し成形法や打錠成形法などにより一定の形状に成形する方法、一定の形状を有する任意の不活性担体上に担持する担持法などがある。これらの方法は適宜選択し、組み合わせて使用することもできる。 Examples of the catalyst forming method include a method of forming the catalyst precursor into a fixed shape by an extrusion method or a tableting method, a support method of supporting the catalyst precursor on an arbitrary inert carrier having a fixed shape, and the like. These methods can be appropriately selected and used in combination.

また、触媒前駆体は粉体状の不活性物質と混合して成形工程に使用することもできる。 Further, the catalyst precursor can be mixed with a powdery inert substance and used in the molding process.

触媒形状に特に制限はなく、球状、円柱状、リング状、不定形などのいずれの形状でもよい。もちろん球状の場合、真球である必要はなく実質的に球状であればよく、円柱状およびリング状についても同様に断面形状は真円である必要は無く、実質的に円形であればよい。 The catalyst shape is not particularly limited, and may be any shape such as a spherical shape, a cylindrical shape, a ring shape, and an indeterminate shape. Of course, in the case of a spherical shape, it does not need to be a true sphere and may be substantially spherical, and the cross-sectional shape does not have to be a perfect circle in the same way for a cylindrical shape and a ring shape, and may be substantially a circular shape.

担持法としては、例えば、特開平６−３８１号公報および特開平１０−２８８７７号公報に記載の不活性担体に触媒活性成分を粉体状で担持させる方法などに準じて製造することができる。 As a supporting method, for example, it can be produced according to a method of supporting a catalytically active component in a powder form on an inert carrier described in JP-A-6-381 and JP-A-10-28877.

成形工程においては、成形性を向上させるための成形助剤やバインダーなどを用いることができる。具体例としては、エチレングリコール、グリセリン、プロピオン酸、マレイン酸、ベンジルアルコール、プロピルアルコール、ブチルアルコールまたはフェノール類の有機化合物や硝酸、硝酸アンモニウム、炭酸アンモニウムなどが挙げられる。 In the molding step, a molding aid or a binder for improving the moldability can be used. Specific examples include organic compounds such as ethylene glycol, glycerin, propionic acid, maleic acid, benzyl alcohol, propyl alcohol, butyl alcohol or phenols, nitric acid, ammonium nitrate, and ammonium carbonate.

また、本触媒には機械的強度を向上させる目的で、補強材として一般に知られているガラス繊維や、シリカ、アルミナ、炭化珪素、窒化珪素などの無機質繊維を添加してもよい。 In addition, for the purpose of improving mechanical strength, the present catalyst may be added with glass fibers generally known as reinforcing materials, and inorganic fibers such as silica, alumina, silicon carbide, silicon nitride and the like.

これらの無機質繊維の添加方法については、特に制限はなく、触媒中に無機質繊維が均一に分散、含有されるようにし得るものであれば、いずれの方法も用いることができる。たとえば、触媒活性成分の出発原料混合液に無機質繊維を添加しても、あるいは触媒活性成分の出発原料混合液を乾燥した後に得られる触媒前駆体に無機質繊維を添加してもよい。 The method for adding these inorganic fibers is not particularly limited, and any method can be used as long as the inorganic fibers can be uniformly dispersed and contained in the catalyst. For example, the inorganic fibers may be added to the starting material mixture of the catalytically active component, or the inorganic fibers may be added to the catalyst precursor obtained after drying the starting material mixture of the catalytically active component.

触媒前駆体を２以上に分割して成形を行う場合は、分割した触媒前駆体毎に、成形方法を変える、成形条件を適宜変更し成形することができる。たとえば、２分割した粉砕物が、粒度分布が異なる場合、バインダーや補強材の種類／量の各条件を変更して成形してもよい。 When the catalyst precursor is divided into two or more and molded, the molding method can be changed for each divided catalyst precursor, and the molding conditions can be changed as appropriate. For example, when the pulverized product divided into two has a different particle size distribution, it may be formed by changing the conditions of the kind / amount of the binder and the reinforcing material.

さらに成形後に乾燥してもよく、その際２以上に分割して乾燥してもよい。 Further, it may be dried after molding, and in that case, it may be divided into two or more and dried.

粉砕物を２以上に分割して成形を行った場合は、続く焼成工程に先んじて、それらの成形体を混合する。
（５）焼成工程
本発明において焼成工程とは、成形工程で得られた成形体あるいは担持体を高温で加熱処理し触媒とする工程である。 When the pulverized product is divided into two or more and molded, those molded bodies are mixed prior to the subsequent firing step.
(5) Firing step In the present invention, the firing step is a step in which the molded body or the support obtained in the molding step is heated at a high temperature to form a catalyst.

焼成工程で用いる焼成炉には特に制限はなく、一般的に使用される箱型焼成炉あるいはトンネル型焼成炉等を用いればよい。焼成温度としては３５０〜６００℃、好ましくは４００〜５５０℃、更に好ましくは４２０〜５００℃、焼成時間としては１〜１５時間、好ましくは２〜１０時間である。焼成雰囲気としては、酸化雰囲気であれば良いが、分子状酸素含有ガス雰囲気が好ましい。分子状酸素含有ガスとしては空気が好適に用いられる。 There are no particular limitations on the firing furnace used in the firing step, and a generally used box-type firing furnace or tunnel-type firing furnace may be used. The firing temperature is 350 to 600 ° C, preferably 400 to 550 ° C, more preferably 420 to 500 ° C, and the firing time is 1 to 15 hours, preferably 2 to 10 hours. The firing atmosphere may be an oxidizing atmosphere, but a molecular oxygen-containing gas atmosphere is preferred. Air is suitably used as the molecular oxygen-containing gas.

成形体あるいは担持体を２以上に分割して焼成を行う場合は、焼成装置を変えて焼成する、同じ装置を二つ以上用意して焼成する、同じ装置で２回以上に分けて焼成する方法などが採用できる。
分割した成形体あるいは担持体の形態が異なる場合は、焼成条件を適宜変更し焼成を行うことができる。たとえば、２分割した成形体あるいは担持体が、触媒サイズが異なる場合、焼成炉の種類、焼成温度、焼成時間などの条件を変更して焼成してもよい。 When firing by dividing the molded body or the carrier into two or more, a method of firing by changing the firing device, preparing two or more of the same device, firing in two or more times in the same device Etc. can be adopted.
When the form of the divided molded body or carrier is different, the firing conditions can be changed as appropriate to perform firing. For example, when the molded product or the carrier divided into two parts has a different catalyst size, it may be fired by changing conditions such as the type of firing furnace, the firing temperature, and the firing time.

成形体あるいは担持体を２以上に分割して焼成を行った場合は、それらの焼成品を混合するか、混合しながら一時的に保管するための容器に充填するか、あるいは混合しながら反応器の各反応管に充填するのに必要な量に小分けし、反応器に充填する。 When the molded body or the carrier is divided into two or more and fired, the fired products are mixed, filled into a container for temporary storage while mixing, or the reactor while mixing Divide into the amount necessary to fill each reaction tube and fill the reactor.

ここでいう混合とは、焼成品自体を混ぜ合わせること、あるいは焼成炉内における配置を変更することを意味し、その他同様の効果が得られる方法も含む。混合する方法としては、特に制限はなく、焼成品を、例えばホッパーなどに一度入れて混合するなど一般的な混合、あるいは、例えば、トレー等の容器に成形体あるいは担持体を入れて焼成する場合、そのトレーの位置を変更するなど焼成炉内の位置を変更すればよいが、好ましくは前者である。 The term “mixing” as used herein means mixing the fired product itself or changing the arrangement in the firing furnace, and includes other methods that can achieve the same effect. The mixing method is not particularly limited. For example, when the baked product is mixed in a hopper or the like once and mixed, or for example, a molded body or a carrier is put in a container such as a tray and baked. The position in the baking furnace may be changed by changing the position of the tray, but the former is preferable.

本発明の製造方法は、従来より公知の酸化物触媒の製造に使用することができる。具体的には、下記一般式（１）で表される触媒活性成分を有する酸化物触媒の製造に好適に使用できる。
Ｍｏ_１２Ｂｉ_ａＦｅ_ｂＡ_ｃＢ_ｄＣ_ｅＤ_ｆＯ_ｘ（１）
（ここで、Ｍｏはモリブデン、Ｂｉはビスマス、Ｆｅは鉄、Ａはコバルトおよびニッケルからなる群より選ばれる少なくとも一種の元素、Ｂはアルカリ金属、アルカリ土類金属およびタリウムからなる群より選ばれる少なくとも一種の元素、Ｃはタングステン、ケイ素、アルミニウム、チタンおよびジルコニウムからなる群より選ばれる少なくとも一種の元素、Ｄはリン、テルル、アンチモン、スズ、セリウム、鉛、ニオブ、マンガン、砒素および亜鉛からなる群より選ばれる少なくとも一種の元素、Ｏは酸素を表し、ａ、ｂ、ｃ、ｄ、ｅ、ｆおよびｘはそれぞれＢｉ、Ｆｅ、Ａ、Ｂ、Ｃ、Ｄ及びＯの原子比を表し、０＜ａ≦１０、０＜ｂ≦２０、２≦ｃ≦２０、０＜ｄ≦１０、０≦ｅ≦３０、０≦ｆ≦４であり、ｘは各元素の酸化状態により定まる値をとる。）
本発明においては、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルから選ばれる少なくとも一種の化合物を、分子状酸素または分子状酸素含有ガスにより接触気相酸化して、対応する不飽和アルデヒドおよび不飽和カルボン酸を製造するに際して、上記の方法で製造された触媒の存在下に行えるものであれば、用いる反応器については特段の制限はなく、固定床反応器、流動床反応器、移動床反応器のいずれも用いることができるが、本願発明においては、固定床反応器が好適に用いられる。 The production method of the present invention can be used for production of conventionally known oxide catalysts. Specifically, it can be suitably used for the production of an oxide catalyst having a catalytically active component represented by the following general formula (1).
_{_{_{_{Mo 12 Bi a Fe b A c}}}} B d C e D f O x (1)
(Where Mo is molybdenum, Bi is bismuth, Fe is iron, A is at least one element selected from the group consisting of cobalt and nickel, and B is at least selected from the group consisting of alkali metals, alkaline earth metals and thallium. One element, C is at least one element selected from the group consisting of tungsten, silicon, aluminum, titanium and zirconium, D is a group consisting of phosphorus, tellurium, antimony, tin, cerium, lead, niobium, manganese, arsenic and zinc At least one element selected from O, oxygen represents oxygen, a, b, c, d, e, f, and x represent atomic ratios of Bi, Fe, A, B, C, D, and O, and 0 < a ≦ 10, 0 <b ≦ 20, 2 ≦ c ≦ 20, 0 <d ≦ 10, 0 ≦ e ≦ 30, 0 ≦ f ≦ 4, and x depends on the oxidation state of each element. It takes a determined value.)
In the present invention, at least one compound selected from propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether is subjected to catalytic gas phase oxidation with molecular oxygen or a molecular oxygen-containing gas, and the corresponding unsaturated aldehyde is obtained. And the unsaturated carboxylic acid can be produced in the presence of the catalyst produced by the above method, there are no particular restrictions on the reactor used, and there are fixed bed reactor, fluidized bed reactor, transfer Any of the bed reactors can be used, but in the present invention, a fixed bed reactor is preferably used.

本発明で使用する反応原料は、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルから選ばれる少なくとも一種の化合物または該化合物含有ガスである。本発明は例えばプロピレンを出発原料とする２工程の接触気相酸化によるアクリル酸の製造における第１工程として重要であり、得られたアクロレイン含有の生成ガスをそのまま、あるいはアクロレインを分離し、必要に応じて、酸素、水蒸気その他のガスを添加して、第２工程のアクロレイン酸化に用いることもできる。 The reaction raw material used in the present invention is at least one compound selected from propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether or the compound-containing gas. The present invention is important as the first step in the production of acrylic acid by, for example, two-step catalytic gas phase oxidation using propylene as a starting material, and the obtained acrolein-containing product gas is used as it is or after separation of acrolein. Accordingly, oxygen, water vapor and other gases can be added and used for acrolein oxidation in the second step.

本発明における、プロピレン、イソブチレン、ｔ−ブチルアルコールおよびメチル−ｔ−ブチルエーテルから選ばれる少なくとも一種の化合物または該化合物含有ガスを反応原料とし、分子状酸素または分子状酸素含有ガスでの接触気相酸化による不飽和アルデヒドおよび不飽和カルボン酸を製造する方法においては、反応条件に特に制限はなく、この種の反応に一般に用いられている条件下に実施することができる。例えば、プロピレンからアクロレインおよびアクリル酸を製造する反応の定常状態での設定条件として、反応原料ガス組成として、１〜１５体積％好ましくは４〜１２体積％のプロピレン、０．５〜２５体積％好ましくは２〜２０体積％の分子状酸素、０〜３０体積％好ましくは０〜２５体積％の水蒸気、残部が窒素などの不活性ガスからなる混合ガスを２８０〜４３０℃、好ましくは２８０〜４００℃の温度範囲で０．１〜１．０ＭＰａの反応圧力下で、１００〜６００ｈｒ^−１（標準状態）、好ましくは１２０〜３００ｈｒ^−１（標準状態）のプロピレン空間速度で酸化触媒に接触させればよい。 In the present invention, at least one compound selected from propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether or a gas containing the compound is used as a reaction raw material, and catalytic gas phase oxidation with molecular oxygen or molecular oxygen-containing gas is performed. In the method for producing an unsaturated aldehyde and an unsaturated carboxylic acid according to the method, the reaction conditions are not particularly limited, and the reaction can be carried out under the conditions generally used for this kind of reaction. For example, as a setting condition in the steady state of the reaction for producing acrolein and acrylic acid from propylene, the reaction raw material gas composition is 1 to 15% by volume, preferably 4 to 12% by volume, preferably 0.5 to 25% by volume. Is a mixed gas composed of 2 to 20% by volume of molecular oxygen, 0 to 30% by volume, preferably 0 to 25% by volume of water vapor, and the balance being an inert gas such as nitrogen, 280 to 430 ° C., preferably 280 to 400 ° C. In the temperature range of 0.1 to 1.0 MPa under a reaction pressure of 100 to 600 hr ⁻¹ (standard state), preferably 120 to 300 hr ⁻¹ (standard state) at a propylene space velocity of contact with the oxidation catalyst. Good.

反応原料ガスとしての原料グレードについては特に制限はなく、例えば、原料としてプロピレンを用いる場合、ポリマーグレードやケミカルグレードのプロピレンなどを用いることができる。また、プロパンの脱水素反応や酸化脱水素反応によって得られるプロピレン含有の混合ガスも使用可能であり、この混合ガスに必要に応じ、空気または酸素などを添加して使用することもできる。 The raw material grade as the reaction raw material gas is not particularly limited. For example, when propylene is used as the raw material, polymer grade or chemical grade propylene can be used. Also, a propylene-containing mixed gas obtained by a propane dehydrogenation reaction or an oxidative dehydrogenation reaction can be used. If necessary, air or oxygen can be added to the mixed gas.

以下に、実施例を挙げて本発明を具体的に説明するが、本発明はこれにより何ら限定されるものではない。なお、以下では、便宜上、「質量部」を単に「部」、と記すことがある。
［触媒性能評価］
転化率および収率は以下の式により算定した。
転化率（モル％）
＝｛（反応した出発原料のモル数）／（供給した出発原料のモル数）｝×１００
収率（モル％）
＝｛（生成した不飽和アルデヒドおよび不飽和カルボン酸のモル数）／（供給した出発原料のモル数）｝×１００
［触媒強度測定方法］
内径２５ｍｍ、長さ５０００ｍｍのステンレス製反応管を鉛直方向に設置し、該反応管の下端を厚さ１ｍｍのステンレス製受け板で塞ぐ。約５０ｇの触媒を評量し、該反応管の上端から反応管内に落下させた後、反応管下端のステンレス製受け板を外し、反応管から触媒を静かに抜き出す。抜き出した触媒を目開き５ｍｍの篩でふるい、篩上に残った触媒の質量を計量した。
触媒強度（質量％）
＝｛（篩上に残った触媒の質量）／（反応管上端から落下させた触媒の質量）｝×１００
＜実施例１＞
［触媒の調製］
蒸留水２０００部を加熱攪拌しつつモリブデン酸アンモニウム５００部を溶解した（Ａ液）。別に５００部の蒸留水に硝酸コバルト３９８部および硝酸ニッケル１１７部を溶解させ（Ｂ液）、さらに別途、３５０部の蒸留水に濃硝酸（６５ｗｔ％）３０部を加えて酸性とした溶液に硝酸第二鉄１０５部および硝酸ビスマス１４９部を溶解させた（Ｃ液）。Ａ液にこれらの硝酸塩溶液（Ｂ液、Ｃ液）を滴下した。引き続き、硝酸カリウム１．９部を５０部の蒸留水に溶解した液を加えた。このようにして得られた懸濁液を濃縮し、粘土状になるまで攪拌した後放置し、ケーキ状の固形物を得た。得られた固形物をトンネル型乾燥機に搬入し、空気雰囲気下１８０℃で１４時間乾燥後に、粒径が３００μｍ以下になるようにハンマーミルで粉砕した。転動造粒機に平均粒径５．２ｍｍのアルミナ球状担体５５０部を投入し、次いで結合剤として２０質量％の硝酸アンモニウム水溶液とともに、得られた粉砕物を徐々に投入して担体に担持させた。得られた担持体を、１４４枚の焼成用トレーに各トレーにつきほぼ同一量となるように入れ、１段につきトレー１２枚を挿入できる１２段積みの箱型焼成炉２台を使用して、各々空気雰囲気下４７０℃で６時間焼成した。焼成した触媒を混合し触媒１−１を得た。同じ操作を繰り返しもう１ロット触媒を調製し触媒１−２を得た。これらの触媒はいずれも担持率は約１１０質量％であり、担体および酸素を除く金属元素組成は原子比で次のとおりであった。
Ｍｏ_１２Ｂｉ_１．３Ｆｅ_１．１Ｃｏ_５．８Ｎｉ_１．７Ｋ_０．０８
なお、担持率は下記式により求めた。
担持率（質量％）＝｛（触媒の質量−使用した担体の質量）／（使用した担体の質量）｝×１００
触媒１−１および触媒１−２の触媒強度およびプロピレンの酸化反応の結果を表１に示す。なお、プロピレンの酸化反応は以下の様に行った。
［反応器］
全長３０００ｍｍ、内径２５ｍｍの鋼鉄製の反応管と、これを覆う熱媒体を流すためのシェルとからなる反応器を鉛直方向に用意した。反応管上部より触媒を落下させて、反応帯の層長が２９００ｍｍとなるように充填した。
［酸化反応］
熱媒体温度を３２０℃に保ち、触媒を充填した反応管に、プロピレン８．０容量％、酸素１５．２容量％、水蒸気９．８容量％、残りは窒素等の不活性ガスからなる混合ガスを、プロピレン空間速度１２５ｈｒ^−１（標準状態）で導入し、プロピレン酸化反応を行った。＜実施例２＞
実施例１において、得られた担持体を、１４４枚の焼成用トレーに各トレーにつきほぼ同一量となるように入れ、１段につきトレー１２枚を挿入できる１２段積みの箱型焼成炉を使用して、得られた担持体の半量ずつを２回に分けて各々空気雰囲気下４７０℃で６時間焼成し、焼成した触媒を混合した以外は実施例１と同様に触媒を２ロット調製し、触媒２−１および触媒２−２を得た。これらの触媒の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒２−１および触媒２−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜比較例１＞
実施例１において、得られた担持体を、２８８枚の焼成用トレーに各トレーにつきほぼ同一量となるように入れ、１段につきトレー２０枚を挿入できる１５段積みの箱型焼成炉を使用して、担持体全量を一度に空気雰囲気下４７０℃で６時間焼成した以外は実施例１と同様に触媒を２ロット調製し、触媒３−１および触媒３−２を得た。これらの触媒の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒３−１および触媒３−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜実施例３＞
実施例１において、得られた担持体を、その平均粒径が６．５ｍｍを超える担持体とそれ以下のものに２分割し、平均粒径が６．５ｍｍを超える担持体を空気雰囲気下４７５℃で６時間焼成し、平均粒径が６．５ｍｍ以下の担持体を空気雰囲気下４６５℃で６時間焼成し、焼成した触媒を混合した以外は実施例１と同様に触媒を２ロット調製し、触媒４−１および触媒４−２を得た。これらの触媒の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒４−１および触媒４−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜実施例４＞
［触媒の調製］
蒸留水２０００部を加熱攪拌しつつモリブデン酸アンモニウム５００部を溶解した（Ａ液）。別に５００部の蒸留水に硝酸コバルト４８１部を溶解させ（Ｂ液）、さらに別途、３５０部の蒸留水に濃硝酸（６５ｗｔ％）３０部を加えて酸性とした溶液に硝酸第二鉄１４３部および硝酸ビスマス２０６部を溶解させた（Ｃ液）。Ａ液にこれらの硝酸塩溶液（Ｂ液、Ｃ液）を滴下した。引き続き、硝酸カリウム１．２部を５０部の蒸留水に溶解した液を加えた。このようにして得られた懸濁液を濃縮し、粘土状になるまで攪拌した後放置し、ケーキ状の固形物を得た。得られた固形物を空気雰囲気下１８５℃で１２時間乾燥後に、粒径が５００μｍ以下になるようにハンマーミルで粉砕した。その際、粉砕は連続的に実施したが、全体の半分程度粉砕した後、一度粉砕機を停止しフィルターなどを清掃した。粉砕物は粉砕機を停止する前後で２分割し、粉砕の前半で得られた粉砕物に、粉砕物１００部あたりに対してバインダーとして５０質量％の硝酸アンモニウム水溶液２１部および補強材として平均繊維径１０μｍ、平均繊維長５００μｍの無アルカリガラス繊維２部を加えて混練した後、外径６．５ｍｍ、内径２ｍｍ、長さ７ｍｍのリング状に押し出し成形した。粉砕の後半で得られた残りの半量の粉砕物へのバインダーとしての硝酸アンモニウム水溶液の添加量は、粉砕の前半で得られた粉砕物へのバインダー添加量の１割減とし、それ以外は同様にして成形した。次いでこれら成形体を混合し、２８８枚の焼成用トレーに各トレーにつきほぼ同一量となるように入れ、１段につきトレー２０枚を挿入できる１５段積みの箱型焼成炉を使用して、空気雰囲気下４７０℃で６時間焼成して触媒５−１を得た。同じ操作を繰り返しもう１ロット触媒を調製し触媒５−２を得た。これらの触媒のガラス繊維と酸素を除く金属元素組成は次のとおりであった。
Ｍｏ_１２Ｂｉ_１．８Ｆｅ_１．５Ｃｏ_７Ｋ_０．０５
これらの触媒５−１および触媒５−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜比較例２＞
実施例４において、得られた粉砕物を２分割せずに、また、バインダー添加量も変更しなかった以外は、実施例４と同様に触媒を２ロット調製し、触媒６−１および触媒６−２を得た。これらの触媒のガラス繊維と酸素を除く金属元素組成は実施例４と同じであった。得られた触媒６−１および触媒６−２の触媒強度、および、実施例４と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜実施例５＞
実施例１において、乾燥物をトンネル型乾燥機より搬出する際、粉砕機に投入する前に、乾燥機の搬出口に目開きが２０ｍｍの網目篩いを設置して、篩いを通過する小さな乾燥物と篩いを通過しない大きな乾燥物に２分割した。小さな乾燥物は粉砕物の粒度が３００μｍ以下の範囲となるまでハンマーミルで粉砕をおこなった。続いて大きな乾燥物は、粉砕条件を変更したり、一度粉砕したものを再度粉砕したりして、粉砕物の粒度が５０〜１５０μｍの範囲となるまでハンマーミルで粉砕した。得られた二つの粉砕物を混合して担持に使用した以外は、実施例１と同様に触媒を２ロット調製し、触媒７−１および触媒７−２を得た。これらの触媒の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒７−１および触媒７−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜実施例６＞
実施例１において、得られたケーキ状の原料混合物を乾燥機に搬入する際、原料混合物を目開きが２０ｍｍの網目篩いで篩い分け、大きいものと小さいものとに２分割した。篩いを通過する小さな原料混合物は箱型乾燥機に搬入し、空気雰囲気下２００℃で５時間乾燥し、大きな原料混合物はトンネル型乾燥機に搬入し、空気雰囲気下１８０℃で１４時間乾燥した。得られた乾燥物を混合して粉砕した。それ以外は、実施例１と同様に触媒を２ロット調製し、触媒８−１および触媒８−２を得た。これらの触媒の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒８−１および触媒８−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜実施例７＞
実施例１において、原料混合物は懸濁液を濃縮する前に、その半分量を表面温度１４０℃のドラムドライヤーで乾燥し、残りの懸濁液は濃縮しケーキ状の固形物とした後、トンネル型乾燥機に搬入し、空気雰囲気下１８０℃で１４時間乾燥した。得られた乾燥物を混合して粉砕した。それ以外は、実施例１と同様に触媒を２ロット調製し、触媒９−１および触媒９−２を得た。これらの触媒９の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒９−１および触媒９−２の触媒強度、および、実施例１と同条件でプロピレンの酸化反応を行った結果を表１に示す。
＜実施例８＞
実施例１において、原料混合物は懸濁液を濃縮する前に、その半分量を１５０℃のスプレードライヤーで乾燥し、残りの懸濁液は濃縮しケーキ状の固形物とした後、箱型乾燥機に搬入し、空気雰囲気下２００℃で５時間乾燥し、得られた乾燥物を混合して粉砕したこと、および成形で得られた担持体を、２８８枚の焼成用トレーに各トレーにつきほぼ同一量となるように入れ、１段につきトレー２０枚を挿入できる１５段積みの箱型焼成炉を使用して、担持体全量を一度に空気雰囲気下４７０℃で６時間焼成した以外は実施例１と同様に触媒を２ロット調製し、触媒１０−１および触媒１０−２を得た。触媒１０−１および触媒１０−２の担持率、担体および酸素を除く金属元素組成は実施例１と同じであった。得られた触媒１０−１および触媒１０−２の触媒強度、および、実施例１と同条件で酸化反応を行った結果を表１に示す。
・ Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. Hereinafter, for convenience, “parts by mass” may be simply referred to as “parts”.
[Catalyst performance evaluation]
Conversion and yield were calculated by the following formula.
Conversion rate (mol%)
= {(Mole number of reacted starting material) / (Mole number of supplied starting material)} × 100
Yield (mol%)
= {(Mole number of unsaturated aldehyde and unsaturated carboxylic acid produced) / (Mole number of supplied starting material)} × 100
[Catalyst strength measurement method]
A stainless steel reaction tube having an inner diameter of 25 mm and a length of 5000 mm is installed in the vertical direction, and the lower end of the reaction tube is closed with a stainless steel receiving plate having a thickness of 1 mm. About 50 g of the catalyst is weighed and dropped into the reaction tube from the upper end of the reaction tube, and then the stainless steel receiving plate at the lower end of the reaction tube is removed, and the catalyst is gently extracted from the reaction tube. The extracted catalyst was sieved with a sieve having an opening of 5 mm, and the mass of the catalyst remaining on the sieve was weighed.
Catalyst strength (mass%)
= {(Mass of catalyst remaining on the sieve) / (mass of catalyst dropped from the upper end of the reaction tube)} × 100
<Example 1>
[Preparation of catalyst]
While heating and stirring 2000 parts of distilled water, 500 parts of ammonium molybdate was dissolved (solution A). Separately, 398 parts of cobalt nitrate and 117 parts of nickel nitrate were dissolved in 500 parts of distilled water (Liquid B), and nitric acid was added to a solution made acidic by adding 30 parts of concentrated nitric acid (65 wt%) to 350 parts of distilled water. 105 parts of ferric iron and 149 parts of bismuth nitrate were dissolved (solution C). These nitrate solutions (B solution and C solution) were added dropwise to the A solution. Subsequently, a solution prepared by dissolving 1.9 parts of potassium nitrate in 50 parts of distilled water was added. The suspension thus obtained was concentrated, stirred until it became a clay, and allowed to stand to obtain a cake-like solid. The obtained solid was carried into a tunnel dryer, dried in an air atmosphere at 180 ° C. for 14 hours, and then pulverized with a hammer mill so that the particle size was 300 μm or less. 550 parts of an alumina spherical carrier having an average particle diameter of 5.2 mm were put into a rolling granulator, and then the obtained pulverized product was gradually put together with a 20 mass% ammonium nitrate aqueous solution as a binder to be supported on the carrier. . Put the obtained carrier in 144 baking trays so that each tray has almost the same amount, and use two 12-layer box type baking furnaces that can insert 12 trays per stage, Each was fired at 470 ° C. for 6 hours in an air atmosphere. The calcined catalyst was mixed to obtain catalyst 1-1. The same operation was repeated to prepare another lot of catalyst to obtain catalyst 1-2. All of these catalysts had a loading rate of about 110% by mass, and the metal element composition excluding the carrier and oxygen was as follows in terms of atomic ratio.
Mo ₁₂ Bi _1.3 Fe _1.1 Co _5.8 Ni _1.7 K _0.08
The loading rate was determined by the following formula.
Loading rate (mass%) = {(mass of catalyst−mass of used carrier) / (mass of used carrier)} × 100
Table 1 shows the catalyst strength of catalyst 1-1 and catalyst 1-2 and the results of the oxidation reaction of propylene. In addition, the oxidation reaction of propylene was performed as follows.
[Reactor]
A reactor consisting of a steel reaction tube having a total length of 3000 mm and an inner diameter of 25 mm and a shell for flowing a heat medium covering the tube was prepared in the vertical direction. The catalyst was dropped from the upper part of the reaction tube and filled so that the layer length of the reaction zone was 2900 mm.
[Oxidation reaction]
A mixed gas composed of 8.0% by volume of propylene, 15.2% by volume of oxygen, 9.8% by volume of water vapor, and the remainder of an inert gas such as nitrogen in a reaction tube filled with a catalyst while maintaining the heat medium temperature at 320 ° C. Was introduced at a propylene space velocity of 125 hr ⁻¹ (standard state) to carry out a propylene oxidation reaction. <Example 2>
In Example 1, the obtained carrier was placed in 144 baking trays so that each tray had almost the same amount, and a 12-stage box-type baking furnace capable of inserting 12 trays per stage was used. Then, half of the obtained support was divided into two portions, each was calcined at 470 ° C. for 6 hours in an air atmosphere, and two lots of the catalyst were prepared in the same manner as in Example 1 except that the calcined catalyst was mixed. Catalyst 2-1 and catalyst 2-2 were obtained. The supporting rate of these catalysts, the metal element composition excluding the carrier and oxygen were the same as those in Example 1. Table 1 shows the catalyst strength of the obtained catalyst 2-1 and catalyst 2-2, and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Comparative Example 1>
In Example 1, the obtained carrier was placed in 288 baking trays so that each tray had almost the same amount, and a 15-stage box type baking furnace in which 20 trays could be inserted per stage was used. Then, two lots of catalysts were prepared in the same manner as in Example 1 except that the entire amount of the support was calcined at 470 ° C. for 6 hours at a time in an air atmosphere to obtain Catalyst 3-1 and Catalyst 3-2. The supporting rate of these catalysts, the metal element composition excluding the carrier and oxygen were the same as those in Example 1. Table 1 shows the catalyst strength of the obtained catalyst 3-1 and catalyst 3-2 and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Example 3>
In Example 1, the obtained carrier was divided into a carrier having an average particle size exceeding 6.5 mm and a carrier having an average particle size exceeding 6.5 mm, and the carrier having an average particle size exceeding 6.5 mm was 475 in an air atmosphere. Two lots of catalyst were prepared in the same manner as in Example 1 except that the carrier having an average particle size of 6.5 mm or less was calcined at 465 ° C. for 6 hours in an air atmosphere and the calcined catalyst was mixed. Catalyst 4-1 and catalyst 4-2 were obtained. The supporting rate of these catalysts, the metal element composition excluding the carrier and oxygen were the same as those in Example 1. Table 1 shows the catalyst strength of the obtained catalyst 4-1 and catalyst 4-2, and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Example 4>
[Preparation of catalyst]
While heating and stirring 2000 parts of distilled water, 500 parts of ammonium molybdate was dissolved (solution A). Separately, 481 parts of cobalt nitrate was dissolved in 500 parts of distilled water (Liquid B), and 143 parts of ferric nitrate were added to a solution made acidic by adding 30 parts of concentrated nitric acid (65 wt%) to 350 parts of distilled water. And 206 parts of bismuth nitrate were dissolved (solution C). These nitrate solutions (B solution and C solution) were added dropwise to the A solution. Subsequently, a solution prepared by dissolving 1.2 parts of potassium nitrate in 50 parts of distilled water was added. The suspension thus obtained was concentrated, stirred until it became a clay, and allowed to stand to obtain a cake-like solid. The obtained solid was dried in an air atmosphere at 185 ° C. for 12 hours, and then pulverized with a hammer mill so that the particle size was 500 μm or less. At that time, pulverization was carried out continuously, but after pulverizing about half of the whole, the pulverizer was stopped once and the filter and the like were cleaned. The pulverized product was divided into two parts before and after stopping the pulverizer, and the pulverized product obtained in the first half of the pulverization was divided into 21 parts of a 50% by weight ammonium nitrate aqueous solution as a binder and an average fiber diameter as a reinforcing material per 100 parts of the pulverized product. After adding 2 parts of alkali-free glass fiber having an average fiber length of 10 μm and kneading and kneading, it was extruded into a ring shape having an outer diameter of 6.5 mm, an inner diameter of 2 mm, and a length of 7 mm. The amount of ammonium nitrate aqueous solution added as the binder to the remaining half of the pulverized product obtained in the latter half of the pulverization was reduced by 10% of the amount of binder added to the pulverized product obtained in the first half of the pulverization. And molded. These compacts are then mixed and placed in 288 firing trays so that each tray has approximately the same amount, using a 15-stage box firing furnace in which 20 trays can be inserted per stage. The catalyst 5-1 was obtained by calcining at 470 ° C. for 6 hours in an atmosphere. The same operation was repeated to prepare another lot of catalyst to obtain catalyst 5-2. The metal element composition excluding glass fiber and oxygen of these catalysts was as follows.
Mo ₁₂ Bi _1.8 Fe _1.5 Co ₇ K _0.05
Table 1 shows the catalyst strengths of these catalysts 5-1 and 5-2, and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Comparative example 2>
In Example 4, two lots of catalysts were prepared in the same manner as in Example 4 except that the obtained pulverized product was not divided into two and the amount of addition of the binder was not changed, and Catalyst 6-1 and Catalyst 6 were prepared. -2 was obtained. The metal element composition of these catalysts excluding glass fibers and oxygen was the same as in Example 4. Table 1 shows the catalyst strength of the obtained catalyst 6-1 and catalyst 6-2 and the results of the oxidation reaction of propylene under the same conditions as in Example 4.
<Example 5>
In Example 1, when the dried product is carried out from the tunnel-type dryer, before being put into the pulverizer, a mesh sieve having a mesh opening of 20 mm is installed at the outlet of the dryer, and the small dried product that passes through the sieve. And divided into two large dried products that did not pass through a sieve. The small dried product was pulverized with a hammer mill until the pulverized product had a particle size of 300 μm or less. Subsequently, the large dried product was pulverized with a hammer mill until the pulverized product had a particle size in the range of 50 to 150 μm by changing the pulverization conditions or pulverizing the pulverized product again. Two lots of catalysts were prepared in the same manner as in Example 1 except that the obtained two pulverized products were mixed and used for loading to obtain Catalyst 7-1 and Catalyst 7-2. The supporting rate of these catalysts, the metal element composition excluding the carrier and oxygen were the same as those in Example 1. Table 1 shows the catalyst strengths of the obtained catalyst 7-1 and catalyst 7-2 and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Example 6>
In Example 1, when the obtained cake-like raw material mixture was carried into a drier, the raw material mixture was sieved with a mesh sieve having an opening of 20 mm, and divided into two, large and small. The small raw material mixture passing through the sieve was carried into a box-type dryer and dried at 200 ° C. for 5 hours in an air atmosphere, and the large raw material mixture was carried into a tunnel-type dryer and dried at 180 ° C. for 14 hours in an air atmosphere. The obtained dried product was mixed and pulverized. Otherwise, two lots of catalyst were prepared in the same manner as in Example 1 to obtain Catalyst 8-1 and Catalyst 8-2. The supporting rate of these catalysts, the metal element composition excluding the carrier and oxygen were the same as those in Example 1. Table 1 shows the catalyst strength of the obtained catalyst 8-1 and catalyst 8-2 and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Example 7>
In Example 1, before concentrating the suspension, half of the raw material mixture was dried with a drum dryer having a surface temperature of 140 ° C., and the remaining suspension was concentrated to a cake-like solid, followed by tunneling. It was carried into a mold dryer and dried at 180 ° C. for 14 hours in an air atmosphere. The obtained dried product was mixed and pulverized. Otherwise, 2 lots of catalyst were prepared in the same manner as in Example 1 to obtain Catalyst 9-1 and Catalyst 9-2. The supporting rate of these catalysts 9, the metal element composition excluding the carrier and oxygen were the same as in Example 1. Table 1 shows the catalyst strength of the obtained catalyst 9-1 and catalyst 9-2, and the results of the oxidation reaction of propylene under the same conditions as in Example 1.
<Example 8>
In Example 1, half of the raw material mixture is dried with a spray dryer at 150 ° C. before concentrating the suspension, and the remaining suspension is concentrated to a cake-like solid, followed by box drying. The resulting dried product was mixed and pulverized, and the carrier obtained by molding was placed on 288 baking trays for each tray. Example in which all the support was fired at 470 ° C. for 6 hours at a time in an air atmosphere using a 15-stage box firing furnace in which 20 trays can be inserted per stage. Two lots of catalysts were prepared in the same manner as in Example 1 to obtain Catalyst 10-1 and Catalyst 10-2. The loading ratio of catalyst 10-1 and catalyst 10-2, the metal element composition excluding the carrier and oxygen were the same as in Example 1. Table 1 shows the catalyst strengths of the obtained catalyst 10-1 and catalyst 10-2, and the results of the oxidation reaction under the same conditions as in Example 1.
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Claims

Catalytic gas phase oxidation of propylene, isobutylene, t-butyl alcohol or methyl-t-butyl ether using molecular oxygen to produce molybdenum, bismuth and iron for producing the corresponding unsaturated aldehyde and unsaturated carboxylic acid respectively. A method for producing a composite oxide catalyst as an essential component, comprising a raw material mixing step of mixing starting raw materials of catalyst component elements, a drying step of heat-treating the obtained starting raw material mixture, and a pulverization of pulverizing the obtained dry matter Including a step, a molding step for molding the obtained pulverized product, and a firing step for firing the obtained molded body. Among these steps, at least one of a drying step, a pulverization step or a molding step, the starting material mixture to be supplied to step in the process, dry matter or pulverized unsaturated aldehydes, characterized in that processing is divided into two or more Method of manufacturing and the composite oxide catalyst for the production of unsaturated carboxylic acids.

When the starting material mixture, dried product or pulverized product to be processed in at least one of the drying step, pulverizing step or molding step is divided into two or more, it is processed under different conditions. The method for producing a composite oxide catalyst for producing an unsaturated aldehyde and an unsaturated carboxylic acid according to claim 1.

By catalytic vapor phase oxidation of a gas containing at least one raw material compound selected from the group consisting of propylene, isobutylene, t-butyl alcohol and methyl-t-butyl ether in the presence of molecular oxygen or molecular oxygen-containing gas, In the method for producing an unsaturated aldehyde and an unsaturated carboxylic acid corresponding to the raw material compound, the composite oxide catalyst obtained by the production method according to claim 1 or 2 is used. A method for producing a saturated carboxylic acid.