JP3757267B2

JP3757267B2 - Rapid search method for multi-component solid catalysts

Info

Publication number: JP3757267B2
Application number: JP2001221134A
Authority: JP
Inventors: 建彦伊藤; 基佐々木
Original assignee: National Institute of Advanced Industrial Science and Technology AIST
Current assignee: National Institute of Advanced Industrial Science and Technology AIST
Priority date: 2001-07-23
Filing date: 2001-07-23
Publication date: 2006-03-22
Anticipated expiration: 2021-07-23
Also published as: JP2003033667A

Description

【０００１】
【発明の属する技術分野】
本発明は、多元系固体触媒の有効性を迅速に探索する方法に関するものであり、更に詳しくは、調製段階で所定の固体触媒粒子からなる触媒群（混合物）を直接調製し、ついで該触媒群に含まれる固体触媒を種類ごとに分離することなく、該触媒群（混合物）のままその有効性を判別評価することにより、多元系固体触媒の有効性を迅速に探索する方法に関するものである。
【０００２】
【従来の技術】
従来より、各種の化学品の合成、燃料の合成および各種排気ガスの浄化等で非常に多くの触媒が使用されているが、近年、環境問題やエネルギー問題からの要請により、触媒の特性や効率を更に上げるために新たな高性能触媒の迅速な開発が望まれている。
この触媒探索の迅速化はエネルギー・環境問題の改善に貢献できる極めて重要な技術となっている。特に多元系の固体触媒では各成分の組み合わせの数も膨大になり、例えば、５成分系の触媒で互いに異なる１０種ずつの元素を組み合わせたとすると、単なる組み合わせの数だけでも１０万種近くの触媒があることになり、さらには濃度等の組み合わせを含めると更に膨大な数となるため触媒探索の迅速化がどうしても必要となる。
【０００３】
これら多元系の固体触媒の探索にはこれまでのところ適当な迅速化方法がないため、触媒の探索は過去に蓄積したデータや知識から推定して探索範囲を一部に絞り込んで行われており、範囲を絞らない全面的な探索は困難と考えられている。一方、近年、コンビナトリアルケミストリーとして医薬品等を並列的に多数作
る方法が行われている。しかし、固体触媒の場合には、固体そのもの又は固体に担持した成分が特に特定の化合物を作るでもなく触媒特性を持つという特有な問題があるため、通常のコンビナトリアルケミストリーで、固相上に固定した基に対し反応を選択的に繰り返し、固相ごとに分離して最後に生成物を切り出すという、手数が非常に節約でき且つスマートな方法である”いわゆる固相合成法”の適用は困難であると言われている。
更に、固体触媒の分野においては、一般に、調製した触媒についての全ての有効性すなわちその反応性能評価を行う必要があり、求める性能の優劣を示す有効なデータを得るためにはこの部分にも非常に時間がかかるため大量の試料の試験が簡単に行える状況ではない。
実際、固体触媒の調製自体を考えても、先に示したように多元系では、組み合わせの数が極めて多く、調製すべき試料の数も膨大になり、通常の方法により一つづつを並行して独立に作る方法では広範な探索は殆ど不可能である。さりとて何らかの方法で混合物として調製されたものでは各粒子に標識をつけることも困難であり、通常は各粒子ごとに成分分析をするしか区別方法が無いため、簡単にはその分離ができずその結果として種類別の性能評価ができない。
【０００４】
また、通常の触媒調製では、各成分を同時に混合すると、加えた成分が直接相互作用を持った単一組成で、異なった性能を持つ触媒が一種類だけ生成してしまい、予め設定した成分を持つ多種の触媒の混合物はできない。そしてこの場合には活性を向上させる成分と、低下させる成分とが同時に存在する可能性があるためため各成分単独での有効性の評価は困難となる。
このように、触媒探索において最も問題となるのは探索範囲内に有効な触媒が有るか否かが判らないと言うことである。もし、有効な触媒がその範囲にない場合は膨大な数の個別の触媒の調製と評価を含む全ての探索が無駄になる。広範な触媒探索では、具体的にどの組み合わせのどんな組成の触媒が有効かを知る前に、この探索範囲には有効な触媒が存在するか否かを大略知ることが最も効果的である。現在の技術では、有効な触媒が特定のグループの中に存在することが明らかになればそこから個々の触媒を絞り込み最適化することは比較的容易である。
従って、何らかの工夫により簡単に多数の種類の触媒を作り、少ない回数の反応試験を行うことで、ある範囲の成分の組み合わせから成る有効な触媒の存在を明らかにできる方法を見いだせれば、特に新しい分析法や機器を、また特殊な調製法や装置を考案しなくとも既存の方法で有効な触媒の探索の迅速化が可能になる。
しかし、この課題における問題は、これまでに効率的に組成の明らかな多数の触媒を創り出す簡便な方法が無いことと、そこで調製した触媒の中に有効な触媒が有るか否かを短時間で知る方法がないことである。
【０００５】
【発明が解決しようとする課題】
本発明は、上記した問題を解決するためになされたものであって、その目的は、多種の触媒混合物の効率的な簡便調製法と、そこで調製した触媒混合物に関して少ない回数の反応性能評価から探索範囲内での有効な触媒の存在の有無と、有効な触媒構成成分の大略とを明らかにすることを基本とする多元系固体触媒の迅速探索方法を提供することにある。
【０００６】
【問題を解決するための手段】
本発明者らは、種々の触媒調製法や評価方法を検討した結果、複数の固体触媒成分からなる多元系固体触媒の探索において、個々の固体触媒成分を異なる粒子間で相互に干渉させずに混合し予め設定した成分を持つ多種の触媒群（混合物）を調製し、ついで、該触媒群（混合物）をそれに含まれる各固体触媒に各別に分離することなく、そのままたとえば同時に調製される基準となる無処理の混合物と比較・評価することにより、非常に少ない評価回数で有効な触媒の有無を知ることができ、大幅に触媒調製及び評価の手数が省かれることを見いだし本発明を完成するに至った。
【０００７】
すなわち、この出願によれば、以下の発明が提供される。
（１）複数の固体触媒成分からなる多元系固体触媒の迅速探索方法であって、担体上に各触媒成分を段階的に担持する触媒調製法を含み、その第１段階においては、担体を第１段階で担持したい触媒成分数＋１の部分に分割し、その１つを無処理のまま残し、その他の部分にはそれぞれ異なる触媒成分を担持させ、これらを無処理の部分も含め全て混合し、第２段階においては、この混合物を第２段階で担持したい触媒成分数＋１の部分に分割し、このうち１つを無処理のまま残し、その他の部分には、第１段階と同様にしてそれぞれに異なる触媒成分を担持し、第３段階以降、同様な操作を必要な段階まで繰り返すことにより、多種の多元固体触媒粒子からなる触媒群を調製し、ついで該触媒群に含まれる固体触媒の有効性を該触媒群を構成する個々の固体触媒に各別に分離することなく評価することを特徴とする多元系固体触媒の迅速探索方法。
（２）触媒成分の担持を含浸法により行うことを特徴とする上記（１）に記載の多元系固体触媒の迅速探索方法。
（３）含浸法での溶液の量を、担体の細孔容積よりも少なくし、担体粒子間での成分の移動・混合を防止することを特徴とする上記（２）に記載の多元系固体触媒の迅速探索方法。
（４）最終段階の触媒群を評価して有効な触媒群を確定し、引き続きその前の段階で調製した触媒群の有効性についても同様な評価を行い、以降、同様な操作を有効な触媒群が存在する限り遡ることを特徴とする請求項１乃至３の何れかに記載の多元系固体触媒の迅速探索方法。
（５）触媒成分の担持順を変え、全ての触媒成分の担持が一度づつ最終段階で行われることにより得られる触媒群を用い、かつ何れの場合も最終段階で得られた触媒群についてのみその有効性を無処理のものと対比評価することを特徴とする上記（１）乃至（３）の何れかに記載の多元系固体触媒の迅速探索方法。
【０００８】
【発明の実施の形態】
以下、本発明を更に詳細に説明する。
先に示したように、例えば、３０種類の異なる成分を１０種づつのグループに分け、そこから一つずつ成分を選ぶ３成分系の触媒を探索する場合、通常であれば１成分および２成分のものも含め１３３０個の触媒を個別に作り評価しなくてはならない。
【０００９】
これに対して、本発明方法によれば、各々１３３個の触媒を含む１０の触媒混合物として調製でき、各触媒混合物ごとの反応性能評価から有効な触媒の有無と大略の有効成分を探索することができ、触媒調製と評価の手間を大幅に低減することが可能となる。
【００１０】
また、多元系固体触媒の調製に際して、通常の方法により触媒を構成する各成分を同時に担持すると各成分の混合が起こり成分が制御された混合物としては調製できないが、本発明方法により触媒の成分を一段階ずつ多段階に分けて担持することにより、調製時において共存する多種触媒間の成分の混合を防止し予め設定した成分を持つ多種触媒の混合物を簡単に調製することができる。
【００１１】
本発明における重要な知見の第一は、通常、担持型固体触媒の混合物では触媒粒子がある程度の大きさを持っており、粒子内はほぼ均一の組成の触媒であり、種類は粒子を単位として変わるが、これは粒子内で成分が混合した触媒とは異なり、定まった組成の各粒子においては互いに独立してその粒子特有の反応が起こり触媒の混合の影響が大きくでることは少ないという点である。
第二は、混合の影響がでる例は、反応生成物の二次反応が非常に速く、その反応に有効な触媒が混合物の中に含まれる場合にみられるが、この場合でも主反応は進行しているため有効触媒の探索上では大きな障害とならないということである。
第三は、まれに水素の活性化等が関連する反応で、水素の活性化能力を持つものが別に存在し単独では見いだせない活性を示すことがあるが、この様な混合物で新規な反応が起これば新たな発見となりここでの触媒探索を特に妨げるものとはならないということである。
【００１２】
次に、本発明方法において好ましく採用される、触媒調製の自動化等にも適し、機械的・簡便な多元系固体触媒の探索方法を説明する。
【００１３】
この方法は、多元系固体触媒の調製に際して、先ず、第１段階で担持したい成分の数＋１だけに最初の担体等を分割し、１つを残して残り全部に各成分を担持固定したのち、無処理の部分も含め全て混合することにより、第１段階で原理的に調製可能な全ての種類の触媒群（混合物）が調製される。尚、この混合操作の前に各部分から小量の試料を採取しておくことで、有効触媒がこの探索範囲に含まれていることが明らかになった場合に有効触媒の成分の特定が容易となる。
【００１４】
次にこの触媒群（混合物）を第１段階と同様に第２段階で担持する成分＋１に分割し、１つを残して各々の部分に各成分を固定担持する。この操作により可能な全ての異なる２成分、１成分の組み合わせを持つ触媒群（混合物）が簡単に調製でき、それが２段階目の処理成分ごとに無処理の部分も含め（２段階目の成分数＋１）のグループに分けられていることになる。更に混合、分割、成分担持を繰り返すことで更に多段の触媒調製が可能となり、予め設定された成分を持つ原理的に調製可能な全ての触媒群（混合物）を直接に得ることができる。
【００１５】
本発明方法においては、触媒群（混合物）中の各触媒の反応性能は反応評価から直接には求めず、たとえば最終担持の段階で得られる触媒群（混合物）の反応性能を担体や無処理の混合物と比較することにより、この探索範囲内の有効な触媒の有無が判別される。
さらに、本発明方法においては、調製での順序を変え最終段階に調べたい成分が担持されるようにすればその成分が有効か否かが判定でき、実際には担持の順序を変え全ての成分を一度は最終段階に持っていくことにより有効な成分を推定できる。
【００１６】
本発明において、多元触媒の混合物を簡便に調製する方法は、多元触媒間の成分の移動・混合なしに直接に多種の多元触媒の混合物が作れる方法であれば特に制限はない。
通常、最初の出発物質にシリカゲルなどの多孔性担体粒子を用いるのが最も単純であるが、その他、各種の構造規則性物質やアルミナ、ジルコニア等の各種の酸化物系担体の使用も可能である。また、はじめに各種塩類の加水分解等により調製した共沈物等を用いることも可能である。
【００１７】
これらに、各種の触媒成分を担持する方法は、一般的に、固定法との関連で前段で担持した成分が触媒間で移動しない限りにおいては、各種塩溶液の含浸による方法すなわち含浸法、スプレードライ法の他イオン交換法や気相担持法も含め液相、気相など担持方法に特に制限はないが、含浸法が最も簡便であり好ましい。
【００１８】
含浸法により逐次担持する方法においては、吸着性の弱い担体の場合、担体への固定処理が乾燥のみの場合には次の成分の担持において成分の再溶解が起こり、粒子間で前に担持した成分の移動が起こることがあるので、固定処理として焼成や水素還元を行い成分の移動を防止しておくことが好ましい。
【００１９】
また、各々の触媒成分の相互作用が小さくなる場合には乾燥のみで固定し次の担持で再溶解させることが好ましい。
更に、通常の含浸法の場合には、各粒子間で以前に担持した成分の移動混合が起こり易いので、本発明方法においては、これを防止する方法として溶液量を細孔容積よりやや少なくしておくことが好ましい。このような方法を採ると、シリカゲルのような吸着性の弱い担体でも前段で乾燥固定された可溶性の塩の溶出移動を押さえることができ、含浸後乾燥のみでも各触媒成分の混合が抑制され所定の触媒群（混合物）の調製が可能となる。なお、同一成分を複数回に分けて担持乾燥を行えば更に確実に移動を抑えることができるが手数が増える。
【００２０】
また、含浸時の溶液の担体に対する添加は、前に加えた成分の移動を抑えるために振とうしつつなるべく小さい水滴で加えることが好ましい。特に成分の移動を嫌う場合は添加成分を含む溶液を噴霧する事により必要量を吸収させる方法が有効である。この場合にも粒子内に吸収させる水分量は細孔容積よりも少なくしておくことが望ましい。尚、溶媒量が少ないとそこで添加したい成分が添加されない又は濃度の低い部分が生ずる可能性があるが、本発明方法においては、その先の段階に無処理のものとの混合もあり、触媒は常に各種の混合物として存在するため、特に問題とはならない。
【００２１】
本発明方法において、目的とする各触媒成分を予定しないところに移動・混合することなく担持するには基本的には１成分ごとに多段階で担持するのが最も容易であるが、同じ成分が含まれているのであれば、一段階で１成分ずつでなくいくつかの成分を同時に担持することも可能である。
【００２２】
また、簡単な手順で考え得る限りの多種の触媒の混合物を効率よく創り出すには、先ず最初の担体を（１段目で担持しようとしている成分数＋１）に分割し、各成分を分割された異なる部分に各々担持固定したのち無処理の部分も含めて混合し、ついでこれを（２段目で担持しようとしている成分数＋１）に再度分割し、再び次の成分を分割された異なる部分に各々担持固定した後、無処理の部分も含めてまた混合すると言う手順を繰り返すと最も機械的・効率的に無担持から多成分まで考えられる組み合わせの種類を持つ触媒群（混合物）を調製することができる。
【００２３】
なお、探索効率がやや下がることを問題としない場合は、途中で全てを混合せず一部づつを混合する方法を組み合わせることなど各種の方法が利用でき、その方法に特に制限はない。
【００２４】
本発明方法で利用できる触媒粒子の大きさとしては担持が均一にできれば特に制限はないが、当然のことながら粒子が大きい場合は担体の粒子の数が触媒の種類の数より十分に大きいことが必要である。
実際には液の添加と振とうの容易さも含め、１００メッシュより小さい場合は取扱いや、成分の移動が起こり易いなどの理由であまり適当ではない。また、粒子の形状としては球状が扱いやすいが、振とう含浸に問題の無いものであれば破砕状等特に制限はない。
【００２５】
使用する溶媒は水が最も一般的であるが、使用する塩類が溶解するものであればアルコールなど特に制限は無い。
担持する成分の濃度は溶液にでき担体に担持できる範囲では特に制限はない。
【００２６】
評価で使用する触媒の形状に関しては通常はそのままの粒子で用いるが、手間を問題にしないのであれば得られた触媒混合物を成形することや、ハニカムニに塗布するなど特に制限はない。
【００２７】
評価する反応としては固体触媒の評価装置で評価できる範囲では特に制限は無い。触媒性能の評価に際しては、混合物のまま性能評価を行うのであればその方法に特に制限はない。
しかし、その目的とするところにより、評価用の１試料に含まれる触媒の種類を、調製段階での成分の数や繰り返しの段数を調節することなどにより選ぶことが望ましい。活性の確認が容易な特異的な反応では多くの種類をその中に含ませることができ、分析可能な範囲で有ればその数に特に制限はない。なお、活性があまり変わらないものの組み合わせでは、その数をあまり多くすると活性の高いものを確認することが難しくなる。
【００２８】
本発明方法において、触媒群の活性評価をどのような手順で行うかは省力化に大きな影響がある。最も簡単な方法は、最終段階の担持の後さらに無処理の部分も含め全てを混合しこれを評価に用いる方法であり、一度で考えられる全ての組み合わせの触媒の評価ができる。
この方法は活性の有無だけを見ることになり、通常は起こり難い即ち通常は活性のあるものが殆どない反応に特異的に有効な触媒を探索する場合には適しており、大略ではあるが１回の評価で広い範囲の探索ができる。
【００２９】
通常、最も効果的な方法は、最終段で生成した触媒混合物をそのまま最後に処理した成分グループごとに評価し、どれかのグループで有効な触媒の存在が推定された時点で予め取り分けておいたその前の段階の試料について調べて行く方法であり、これで大まかな有効成分の範囲が絞れる。
【００３０】
一方、新たに成分の担持順序を変えて、最後に処理する成分が全て変わるようにして調製すると、未処理の混合物の活性と比較することにより、最後の処理で活性の上がった成分が有効触媒の構成成分である可能性が高くなり、多元系触媒成分の特定ができる。
【００３１】
【実施例】
次に本発明を、メタノールの一酸化炭素と水素への分解触媒の探索に例を取り、実施例及び比較例にによりさらに詳細に説明するが、本発明はこの実施例によって限定されない。また、実施例および比較例の実験におけるガス組成の分析はガスクロマトグラフ法で行った。
【００３２】
実施例１
シリカゲル（３２ー４２メッシュ）３ｇを取りこれを３つの部分に等分割する、この内の一つの部分には担持したときの金属パラジウムの濃度が３％となるよう
に濃度を調節したシリカゲルの細孔容積よりやや少ない塩化パラジウム水溶液を減圧下で含浸し、乾燥する。他の一つには担持したときの金属白金の濃度が３％となるように濃度を調節したシリカゲルの細孔容積よりやや少ない硝酸白金アンモニウム水溶液を減圧下で含浸し乾燥する。最後の一つは何もせずに残す。ここまでが表２での第１段で担体のみも含め３種の触媒が生成したことになる。
この３つの部分から評価用の試料を各々０．１ｇづつ抜き取り残りを良く混合し３分割する。この内の一つの部分に硝酸セリウムの担持後酸化した後で酸化セリウムとして担体の５％に相当する量を、シリカゲル細孔容積よりやや少ない量の水に溶解し、含浸し、乾燥する。もう一つの部分には、硝酸鉄の担持後酸化した後で酸化鉄として担体の５％に相当する量を、シリカゲル細孔容積よりやや少ない量の水に溶解し、含浸し、乾燥する。残りの一つは何も処理せずにそのままにしておく。ここまでが表２での第２段で、担体も含め９種の触媒が生成したことになる。この３つの部分から評価用の試料を各々０．１ｇ抜き取り残りを良く混合し再び３つに等分割する。この内の一つに硝酸ジルコニルの、担持後酸化した後で酸化ジルコニウムとして担体の５％に相当する量を細孔容積よりやや少ない量の水に溶解し、含浸し、乾燥する。次いでこれを３５０℃で焼成し、その後同じ温度で水素還元し約１ｇの触媒を得た（これをＣＡＴ−Ｚｒとする）。もう一つの部分には、硝酸ナトリウムの酸化ナトリウムとして担体の３％に相当する量を細孔容積よりやや少ない量の水に溶解し、含浸し、乾燥する。次いでこれを３５０℃で焼成し、その後同じ温度で水素還元し約１ｇの触媒を得た（これをＣＡＴ−Ｎａとする）。残りの一つは何も処理せずに３５０℃で焼成し、その後同じ温度で水素還元し約１ｇの触媒を得た（これをＣＡＴ−ＲＥＦ１とする）。ここまでが表２の第３段で担体も含め２７種の触媒が生成したことになる。ついで第１段階および第２段階で抜き取った試料も同様な操作で焼成・還元した。（各々Ｐｄ−ＳｉＯ２，Ｐｔ−ＳｉＯ２，ＳｉＯ２、ＭＯＤ−Ｃｅ，ＭＯＤーＦｅ，ＭＯＤ−ＲＥＦ０とする。）
前記の方法で調製した触媒の内０．１ｇを０．１ｇのシリカゲルと混合し、触媒の活性評価用常圧流通式反応装置に充填し、２５０℃で１時間水素還元し１５０℃まで冷却した後、メタノール：ヘリウム：アルゴン＝２：９３：５の混合ガスを２００ｍｌ／分の速度で供給した。そして、触媒層温度を１５０℃に１時間保持した後１７５℃に上げるようにして触媒層温度を１５０、１７５、２００、２２５および２５０℃に１時間ずつ保持し、各温度に１時間保持した後の生成ガスをサンプリングして分析した。反応生成物は９７％以上が一酸化炭素と水素であった。この操作をメタノール濃度２，４，１０，２０％で繰り返した。メタノール濃度２０％、温度２００℃で反応を行った場合の一酸化炭素の収量（ＣＯ収量）（ミリモル／グラムー触媒毎時）を表１に示す。
なお、実施例１での調製手順と生成触媒をまとめたものを参考のため表２に示す。表２の（）は生成した触媒の種類を示す。
【００３３】
実施例２
実施例２の操作手順を表３に示す（ただし表３では混合物に含まれる触媒の種類は示してない）。
シリガゲル６ｇを新たに取り、これを３分割したものに実施例１述べたと同様の方法により第１段としてＺｒまたはＮａを担持し、一部は無処理のまま３者を良く混合し、２分割し、その一方を更に３分割する。
この３分割した各々の部分に第２段として実施例１と同様にしてＣｅまたはＦｅを担持し一部は無処理のままとし、上記と同様に混合したのち３分割する。第３段として各々の部分にＰｄまたはＰｔを担持し、一部は無処理のままとする。それぞれを前記触媒と同様に３５０℃で焼成後同じ温度で水素還元する事によりそれぞれ約１ｇの触媒を得た。各々をＣＡＴ−Ｐｄ、ＣＡＴ−Ｐｔ，ＣＡＴ−ＲＥＦ２とする。
次に、先に第１段目の担持後２分割した残りの部分を更に３分割する。これらに先に示した順とは逆に２段目でＰｄまたはＰｔを担持し、次に３段目でＣｅまたはＦｅを担持し１部は無処理のまま、それぞれ前記触媒と同様に３５０℃で焼成後同じ温度で水素還元しそれぞれ約１ｇの触媒を得た。各々をＣＡＴ−Ｃｅ，ＣＡＴ−Ｆｅ，ＣＡＴ−ＲＥＦ３とする。このようにして得られた触媒を実施例１と同様にして反応特性を評価した。結果を表１に示した。
尚、実施例１のＣＡＴ−Ｚｒ，ＣＡＴ−Ｎａ、ＣＡＴ−ＲＥＦ１と実施例２のＣＡＴ−Ｐｄ，ＣＡＴ−Ｐｔ，ＣＡＴ−ＲＥＦ２，ＣＡＴ−Ｃｅ，ＣＡＴ−Ｆｅ，ＣＡＴ−ＲＥＦ３で使用した成分が全て最後の段階で担持された触媒とその原料触媒が調製でき評価されたことになる。
【００３４】
比較例１
実施例１に示した触媒に含まれる多成分触媒は担体ＳｉＯ２、Ｐｄ／ＳｉＯ２，Ｐｔ／ＳｉＯ２，Ｃｅ／Ｐｄ／ＳｉＯ２，Ｃｅ／Ｐｔ／ＳｉＯ２、Ｆｅ／Ｐｄ／ＳｉＯ２，Ｆｅ／Ｐｔ／ＳｉＯ２、Ｚｒ／Ｃｅ／Ｐｄ／ＳＩＯ２，Ｚｒ／Ｃｅ／Ｐｔ／ＳｉＯ２，Ｚｒ／Ｆｅ／Ｐｄ／ＳｉＯ２，Ｚｒ／Ｆｅ／Ｐｔ／ＳｉＯ２，Ｎａ／Ｃｅ／Ｐｄ／ＳｉＯ２，Ｎａ／Ｃｅ／Ｐｔ／ＳｉＯ２，Ｎａ／Ｆｅ／Ｐｄ／ＳｉＯ２，Ｎａ／Ｆｅ／Ｐｔ／ＳｉＯ２を初めとする２７種であるが、ここでは比較のためＰｄ／ＳｉＯ２，Ｐｔ／ＳｉＯ２，Ｐｄ／Ｃｅ／ＳｉＯ２，Ｐｄ／Ｎａ／ＳｉＯ２，Ｐｄ／Ｚｒ／ＳｉＯ２を調製した。Ｐｔ（３％）−ＳｉＯ２は実施例１と同様な方法で、Ｐｄ（３％）−ＳｉＯ２は焼成を省いた以外は実施例１と同様な方法で、Ｐｄ（３％）−Ｎａ（３％）−ＳｉＯ２についてはＰｄ−ＳｉＯ２に後から硝酸ナトリウムを含浸し、還元する方法で、Ｐｄ（３％）−Ｃｅ（５％）−ＳｉＯ２とＰｄ（３％）−Ｚｒ（５％）−ＳｉＯ２については予めシリカゲルに酸化セリウムまたは酸化ジルコニウムを担持した後、塩化パラジウム溶液を含浸し、乾燥後水素還元して触媒を得た。Ｐｄ−Ｎａ−ＳｉＯ２については実施例１と同様の方法で、その他については触媒量を０．２ｇとしシリカゲルを加えずに反応性能の評価を実施例１と同様の方法で行った。メタノール濃度４％反応温度２００℃の結果を表１に示した。
【００３５】
比較例２
塩化パラジウム、硝酸白金アンモニウム、塩化鉄、硝酸セリウム、硝酸ジルコニル、硝酸ナトリウムをそれぞれ担持後に金属または酸化物として３％、３％，５％，５％，５％，３％となるようにとり、細孔容積とほぼ同量の水で溶解しシリカゲルに含浸担持した。乾燥後、３５０℃で焼成したのち同温度で水素還元し、触媒を得た。これを０．１ｇ取り、実施例１の方法と同様の方法により、反応性能を評価した。メタノール濃度２０％反応温度２００℃での結果を表１に示した。
【００３６】
【表１】

【００３７】
【表２】

【００３８】
【表３】

【００３９】
［実験結果の考察］
表１に示した実施例１のＭＯＤ−ＲＥＦ０の活性はＰｄ−ＳｉＯ２とＰｔ−ＳｉＯ２の活性の合計とほぼ等しくなっており、もう１つ混合したＳｉＯ２は活性がないことを考えると、触媒の混合により特に変わったことも起こらずここでは各触媒の活性の加算がほぼ成立していることがわかる。
表１に示した実施例１のＣＡＴ−Ｚｒ，ＣＡＴ−Ｎａ、ＣＡＴ−ＲＥＦ１の３件の反応性能評価結果を見ると無処理のＣＡＴ−ＲＥＦ１に較べＺｒで処理したものの活性が大きく上がっており、Ｎａで処理したものは活性が下がっていることが明らかになり、有効な触媒の存在と、有効成分としてＺｒが示唆される。この結果は異なる方法で調製した比較例１で見られるＺｒの有効性とＮａの妨害性とも一致しており、この様に活性な触媒の有無だけを調べるのであれば通常は２６件の評価を行わなければならないのに対して本件では僅か３件の評価で結果が得られることを示している。更にＺｒやＮａなど触媒構成成分の効果に関しても有効な知見が得られており、本発明方法の有効性が裏付けられている。
【００４０】
有効な触媒の存在が明らかになった後では、実施例１に示した１段目、２段目の処理で得た試料（Ｐｄ−ＳｉＯ２、Ｐｔ−ＳｉＯ２，ＳｉＯ２、ＭＯＤ−Ｃｅ、ＭＯＤ−Ｆｅ，ＭＯＤ−ＲＥＦ０）を評価し無処理のものと比較することにより、おのおのＣｅ，Ｐｄの有効性が示唆されＺｒ・Ｃｅ・Ｐｄ／ＳｉＯ２系が詳細な調査候補触媒として上がってくることになり、この場合でも少ない手数で触媒の絞り込みが可能である。
更に、活性を向上させる有効成分を明らかにしたい場合は、有効性を確認した実施例１の３件（ＣＡＴ−Ｚｒ，ＣＡＴ−Ｎａ，ＣＡＴ−ＲＥＦ１）の評価後、実施例２で示した調製法を行うことで最終段、即ち、３段目で処理する成分が調製で用いた全ての成分を網羅することになり、実施例１の最終段でＺｒの有効性とＮａの妨害を見たと同様にして、表１のＣＡＴ−Ｐｄ、ＣＡＴ−Ｐｔ，ＣＡＴ−ＲＥＦ２の比較から活性はＰｄ＞ＰｔでありＰｄ又はＰｔは触媒成分として必須であること、およびＣｅとＦｅの効果も分かり、全ての成分についてその効能がおおよそ明らかになり、有効触媒の組成の推定ができる。但し、この場合、評価すべき試料の数は（全成分数＋処理の段数）と成り、成分数が少なく処理段数も少ない場合は特に効果的ではないが、成分数や処理段数が増えると有効な方法となる。
【００４１】
なお評価に必要な反応性能評価実験点数と探索方法との関係は、全ての成分が異なり各段階は同じ成分数として、一段成分数ｍ、組み合わせ段数ｒとし、担体のみの評価も含めると、理論値は次のようになる。

【００４２】
実際に計算すると、必要な反応性能評価実験点数と探索方法との関係は次のようになり、成分数や組み合わせ段数の多い場合の本発明の有効性が実証される。

【００４３】
なお、触媒の成分を初めから混合した触媒では比較例２に示したように活性はＰｄ−ＳｉＯ２とＰｔ−ＳｉＯ２の活性の合計の３分の２となり金属単独の活性よりも低下しており、Ｐｄ−Ｚｒ−ＳｉＯ２などの高活性な触媒の存在が推定できないためこの方法は触媒探索には適していない。
【００４４】
【発明の効果】
本発明方法によれば、所定の固体触媒粒子の集まりからなる触媒群を予め調製しておき、ついで該触媒群に含まれる固体触媒の有効性を該触媒群を構成する個々の固体触媒に各別に分離することなく判別するだけで、有効な多元系固体触媒を迅速に探索できる。従って、個々に多元系固体触媒を調製しておき、その都度その触媒の有効性を判定する従来法に比べ、極めて少ない回数の反応性能評価から探索範囲内での有効な触媒の存在の有無と、有効な触媒構成成分の大略の組み合わせを飛躍的に迅速に探索することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for rapidly searching for the effectiveness of a multi-component solid catalyst, and more specifically, a catalyst group (mixture) composed of predetermined solid catalyst particles is directly prepared in a preparation stage, and then the catalyst group. The present invention relates to a method for quickly searching for the effectiveness of a multi-component solid catalyst by discriminating and evaluating the effectiveness of the catalyst group (mixture) without separating the solid catalyst contained in the catalyst.
[0002]
[Prior art]
Conventionally, a large number of catalysts have been used in the synthesis of various chemicals, the synthesis of fuels, and the purification of various exhaust gases. However, in recent years, due to demands from environmental and energy problems, the characteristics and efficiency of the catalyst have been increased. In order to further improve the performance, rapid development of a new high performance catalyst is desired.
This rapid search for catalysts is an extremely important technology that can contribute to the improvement of energy and environmental problems. In particular, the number of combinations of each component is enormous in a multi-component solid catalyst. For example, if ten different elements are combined in a five-component catalyst, nearly 100,000 types of catalysts can be obtained by a simple combination. In addition, if the combination of concentration and the like is included, the number becomes even larger, so it is necessary to speed up the catalyst search.
[0003]
So far, there is no appropriate expediting method to search for these multi-component solid catalysts, so the search for catalysts has been carried out with a limited search range estimated from data and knowledge accumulated in the past. A full search without narrowing the scope is considered difficult. On the other hand, in recent years, as a combinatorial chemistry, a large number of drugs have been created in parallel.
There is a way to do it. However, in the case of a solid catalyst, there is a particular problem that the solid itself or the component supported on the solid has a catalytic property as well as not producing a specific compound. Therefore, the solid catalyst is fixed on the solid phase by ordinary combinatorial chemistry. It is difficult to apply “so-called solid-phase synthesis method”, which is a smart method that saves time and effort, by selectively repeating the reaction on the group, separating each solid phase, and finally cutting out the product. It is said.
Furthermore, in the field of solid catalysts, it is generally necessary to evaluate all the effectiveness of the prepared catalyst, that is, its reaction performance, and this part is also very useful for obtaining effective data showing the superiority or inferiority of the required performance. It takes a long time to test a large number of samples.
In fact, even if the preparation of the solid catalyst itself is considered, the multi-component system as shown above has a very large number of combinations and the number of samples to be prepared becomes enormous. A broad search is almost impossible with the independent method. It is difficult to label each particle if it is prepared as a mixture by some method, and there is usually only a component analysis for each particle, so it is not possible to separate it easily. As a result, performance evaluation by type is not possible.
[0004]
In addition, in normal catalyst preparation, when each component is mixed at the same time, the added component has a single composition with direct interaction, and only one type of catalyst with different performance is generated. It cannot be a mixture of various catalysts. In this case, since there is a possibility that a component that improves the activity and a component that decreases the activity are present at the same time, it is difficult to evaluate the effectiveness of each component alone.
Thus, the biggest problem in the catalyst search is that it is not known whether there is an effective catalyst within the search range. If an effective catalyst is not in that range, all searches including the preparation and evaluation of a vast number of individual catalysts are wasted. In a broad catalyst search, it is most effective to know roughly whether or not there is an effective catalyst in this search range before knowing which composition and what composition of catalyst is effective. With current technology, it is relatively easy to narrow down and optimize individual catalysts once it becomes clear that effective catalysts exist within a particular group.
Therefore, if a method can be found that makes it possible to clarify the existence of an effective catalyst consisting of a combination of components in a certain range by making a large number of types of catalysts easily by some device and conducting a small number of reaction tests, it is particularly new. It is possible to expedite the search for an effective catalyst by an existing method without devising an analytical method and equipment, and a special preparation method and apparatus.
However, the problem in this problem is that there is no simple method for efficiently creating a large number of catalysts with clear compositions so far, and whether there is an effective catalyst among the prepared catalysts in a short time. There is no way to know.
[0005]
[Problems to be solved by the invention]
The present invention has been made to solve the above-described problems, and its object is to search from an efficient and simple method for preparing various catalyst mixtures and a small number of reaction performance evaluations on the catalyst mixtures prepared there. An object of the present invention is to provide a rapid search method for a multi-component solid catalyst based on clarifying the presence / absence of an effective catalyst within the range and the outline of effective catalyst components.
[0006]
[Means for solving problems]
As a result of examining various catalyst preparation methods and evaluation methods, the present inventors have found that, in searching for multi-component solid catalysts composed of a plurality of solid catalyst components, individual solid catalyst components do not interfere with each other between different particles. A mixture of various catalyst groups (mixtures) having pre-set components is prepared, and then the catalyst groups (mixtures) are prepared as they are, for example, at the same time without being separated into solid catalysts contained therein. By comparing and evaluating with an untreated mixture, it is possible to know the presence or absence of an effective catalyst with a very small number of evaluations, and to find out that the number of steps for catalyst preparation and evaluation is greatly reduced and to complete the present invention. It came.
[0007]
That is, according to this application, the following invention is provided.
(1) A rapid search method for a multi-component solid catalyst composed of a plurality of solid catalyst components, including a catalyst preparation method in which each catalyst component is supported stepwise on a support. Divide into parts of the number of catalyst components +1 to be supported in one stage, leave one of them untreated, and load the other catalyst components in the other parts, mix them all including untreated parts, In the second stage, this mixture is divided into parts of the number of catalyst components +1 to be supported in the second stage, one of which is left untreated, and the other parts are respectively the same as in the first stage. A catalyst group consisting of various multi-element solid catalyst particles is prepared by repeating the same operation from the third stage to the necessary stage after the third stage, and then the effectiveness of the solid catalyst contained in the catalyst group is prepared. The catalyst group Quick method of searching multi-component solid catalyst and evaluating without separating into each other in each of the solid catalyst.
(2) The rapid search method for a multi-component solid catalyst according to (1) above, wherein the catalyst component is supported by an impregnation method.
(3) The multi-component solid as described in (2) above, wherein the amount of the solution in the impregnation method is smaller than the pore volume of the carrier to prevent the movement and mixing of components between the carrier particles A rapid search method for catalysts.
(4) The final catalyst group is evaluated to determine an effective catalyst group, and subsequently the same evaluation is performed for the effectiveness of the catalyst group prepared in the previous stage. The rapid search method for a multi-component solid catalyst according to any one of claims 1 to 3, wherein the process goes back as long as a group exists.
(5) Using a catalyst group obtained by changing the loading order of the catalyst components and carrying all the catalyst components once in the final stage, and in each case only the catalyst group obtained in the final stage The rapid search method for a multi-component solid catalyst according to any one of the above (1) to (3), wherein the effectiveness is evaluated by comparison with an untreated one.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in more detail.
As shown above, for example, when searching for a three-component catalyst in which 30 different components are divided into 10 groups and components are selected one by one, usually one component and two components 1330 catalysts, including those, must be made and evaluated individually.
[0009]
On the other hand, according to the method of the present invention, it can be prepared as 10 catalyst mixtures each containing 133 catalysts, and search for the presence or absence of effective catalysts and the approximate effective components from the reaction performance evaluation for each catalyst mixture. Thus, it is possible to greatly reduce the labor for catalyst preparation and evaluation.
[0010]
In addition, when preparing the multi-component solid catalyst, if each component constituting the catalyst is simultaneously supported by a usual method, the components are mixed and cannot be prepared as a controlled component. However, the catalyst component can be prepared by the method of the present invention. By carrying the catalyst in multiple stages one by one, it is possible to easily prepare a mixture of multi-catalysts having preset components by preventing mixing of the components between the co-existing multi-catalysts during the preparation.
[0011]
The first important finding in the present invention is that the catalyst particles usually have a certain size in the mixture of the supported solid catalyst, and the inside of the particles is a catalyst having a substantially uniform composition. However, this is different from the catalyst in which the components are mixed in the particles, in that each particle having a defined composition is independent from each other and the influence of the mixing of the catalyst is rarely increased. is there.
Secondly, an example where the influence of mixing occurs is when the secondary reaction of the reaction product is very fast and a catalyst effective for the reaction is contained in the mixture, but even in this case, the main reaction proceeds. Therefore, it does not become a major obstacle in searching for an effective catalyst.
The third is a reaction that involves the activation of hydrogen in rare cases, and there are other things that have the ability to activate hydrogen and may show an activity that cannot be found alone. If it happens, it will be a new discovery and will not interfere with the catalyst search here.
[0012]
Next, a method for searching for a mechanical and simple multi-component solid catalyst that is preferably employed in the method of the present invention and that is suitable for automation of catalyst preparation and the like will be described.
[0013]
In this method, in the preparation of the multi-component solid catalyst, first, the first carrier and the like are divided into only the number of components to be supported + 1 in the first stage, and each component is supported and fixed on the rest, leaving one. By mixing all the untreated parts, all kinds of catalyst groups (mixtures) that can be prepared in principle in the first stage are prepared. In addition, by collecting a small amount of sample from each part before this mixing operation, it is easy to identify the components of the effective catalyst when it becomes clear that the effective catalyst is included in this search range. It becomes.
[0014]
Next, this catalyst group (mixture) is divided into components +1 to be supported in the second stage in the same manner as in the first stage, and each component is fixedly supported on each part except one. By this operation, a catalyst group (mixture) having all the possible combinations of two components and one component can be easily prepared, including the untreated portion for each second-stage treated component (second-stage component). It is divided into groups of number +1). Further, by repeating mixing, dividing, and component loading, it is possible to prepare a multistage catalyst, and it is possible to directly obtain all catalyst groups (mixtures) that can be prepared in principle with preset components.
[0015]
In the method of the present invention, the reaction performance of each catalyst in the catalyst group (mixture) is not directly determined from the reaction evaluation. For example, the reaction performance of the catalyst group (mixture) obtained in the final loading stage is determined based on the carrier and the untreated. By comparing with the mixture, the presence or absence of an effective catalyst within this search range is determined.
Furthermore, in the method of the present invention, it is possible to determine whether or not a component is effective by changing the order in preparation and loading the component to be examined in the final stage. The effective component can be estimated by bringing the to the final stage once.
[0016]
In the present invention, the method for easily preparing a mixture of multi-way catalysts is not particularly limited as long as it is a method that can directly make a mixture of various multi-way catalysts without transferring and mixing the components between the multi-way catalysts.
Usually, it is simplest to use porous carrier particles such as silica gel as the first starting material, but it is also possible to use various structural regular substances and various oxide-based carriers such as alumina and zirconia. . It is also possible to use coprecipitates prepared by hydrolysis of various salts at the beginning.
[0017]
In these methods, various catalyst components are generally supported by a method by impregnation with various salt solutions, that is, an impregnation method, a spray, as long as the component supported in the previous stage does not move between the catalysts in connection with the fixing method. There are no particular limitations on the loading method such as liquid phase and gas phase, including dry exchange, ion exchange method and vapor phase loading method, but the impregnation method is the simplest and preferred.
[0018]
In the method of sequentially supporting by the impregnation method, in the case of a carrier having a weak adsorptivity, when the fixing process to the carrier is only drying, the component is redissolved in the loading of the next component, and is previously supported between the particles. Since the movement of the component may occur, it is preferable to prevent the movement of the component by performing baking or hydrogen reduction as the fixing treatment.
[0019]
Moreover, when the interaction of each catalyst component becomes small, it is preferable to fix only by drying and to re-dissolve by the next carrying.
Furthermore, in the case of the normal impregnation method, the components previously carried between the particles are likely to be moved and mixed between the particles. Therefore, in the method of the present invention, the amount of the solution is slightly less than the pore volume as a method for preventing this. It is preferable to keep it. By adopting such a method, it is possible to suppress the elution movement of the soluble salt dried and fixed in the previous stage even with a weakly adsorptive carrier such as silica gel, and the mixing of each catalyst component is suppressed by only drying after impregnation. The catalyst group (mixture) can be prepared. If the same component is divided into a plurality of times and carried and dried, the movement can be more reliably suppressed, but the number of operations increases.
[0020]
In addition, the addition of the solution to the carrier during the impregnation is preferably performed with as small water droplets as possible while shaking to suppress the movement of the previously added components. In particular, when the movement of the component is disliked, a method of absorbing the necessary amount by spraying a solution containing the added component is effective. Also in this case, it is desirable that the amount of water absorbed in the particles is smaller than the pore volume. In addition, if the amount of the solvent is small, there is a possibility that a component to be added there may not be added or a portion having a low concentration may be generated, but in the method of the present invention, there is also a mixture with an untreated one in the previous stage, and the catalyst is Since it always exists as various mixtures, it is not a problem.
[0021]
In the method of the present invention, it is basically easiest to carry each target catalyst component without moving or mixing it in an unscheduled place. If included, it is possible to carry several components simultaneously instead of one component at a time.
[0022]
Moreover, in order to efficiently create a mixture of various kinds of catalysts that can be conceived by a simple procedure, first, the first support was divided into (number of components to be supported in the first stage + 1), and each component was divided. After loading and fixing to each different part, mix it including the unprocessed part, and then divide this again into (number of components to be carried in the second stage + 1), and again the next component into the divided different parts After each supporting and fixing, the catalyst group (mixture) having the kind of combination that can be considered from unsupported to multi-component is most mechanically and efficiently prepared by repeating the procedure of mixing again including the untreated part. Can do.
[0023]
In addition, when it does not matter that the search efficiency is slightly lowered, various methods can be used such as a method of mixing parts one by one without mixing them all in the middle, and the method is not particularly limited.
[0024]
The size of the catalyst particles that can be used in the method of the present invention is not particularly limited as long as the support can be made uniform, but it is a matter of course that when the particles are large, the number of support particles is sufficiently larger than the number of types of catalyst. is necessary.
In practice, including the ease of addition of liquid and shaking, if it is smaller than 100 mesh, it is not very suitable for reasons such as easy handling and transfer of components. In addition, although the spherical shape is easy to handle as the particle shape, there is no particular limitation such as a crushed shape as long as there is no problem with shaking impregnation.
[0025]
The solvent to be used is most commonly water, but is not particularly limited as long as the salt to be used is soluble.
The concentration of the component to be supported is not particularly limited as long as it can be made into a solution and supported on the carrier.
[0026]
The shape of the catalyst used in the evaluation is usually used as it is, but there is no particular limitation such as shaping the obtained catalyst mixture or applying it to the honeycomb as long as labor is not a problem.
[0027]
The reaction to be evaluated is not particularly limited as long as it can be evaluated by the solid catalyst evaluation apparatus. When evaluating the performance of the catalyst, there is no particular limitation on the method as long as the performance is evaluated in the form of a mixture.
However, depending on the purpose, it is desirable to select the type of catalyst contained in one sample for evaluation by adjusting the number of components in the preparation stage and the number of repeated stages. In a specific reaction in which the activity can be easily confirmed, many types can be included therein, and the number is not particularly limited as long as it can be analyzed. In addition, in the combination of those whose activity does not change so much, if the number is increased too much, it becomes difficult to confirm the high activity.
[0028]
In the method of the present invention, the procedure for evaluating the activity of the catalyst group has a great influence on labor saving. The simplest method is a method in which all the components including the untreated portion are mixed and used for evaluation after the final stage of loading, and all combinations of catalysts considered at a time can be evaluated.
This method looks only at the presence or absence of activity, and is suitable when searching for a catalyst that is particularly unlikely to occur, that is, normally effective in a reaction that hardly has activity, and is roughly 1 A wide range of searches can be performed with each evaluation.
[0029]
In general, the most effective method is to evaluate the catalyst mixture produced in the final stage as it is for each component group that has been treated as it is, and to preliminarily determine the existence of an effective catalyst in any group. This is a method of examining the sample in the previous stage, and this can narrow down the range of rough active ingredients.
[0030]
On the other hand, if the loading order of the components is newly changed so that all the components to be processed last are changed, the active component is increased by the last treatment by comparing with the activity of the untreated mixture. Therefore, the multicomponent catalyst component can be specified.
[0031]
【Example】
Next, the present invention will be described in more detail with reference to examples and comparative examples by searching for a catalyst for decomposition of methanol into carbon monoxide and hydrogen, but the present invention is not limited to these examples. Moreover, the analysis of the gas composition in the experiment of an Example and a comparative example was performed by the gas chromatograph method.
[0032]
Example 1
Take 3g of silica gel (32-42 mesh) and equally divide it into three parts. One of these parts has a metal palladium concentration of 3% when supported.
The solution is impregnated with an aqueous palladium chloride solution slightly less than the pore volume of the silica gel whose concentration is adjusted under reduced pressure and dried. The other is impregnated with an aqueous solution of ammonium platinum nitrate, which is slightly smaller than the pore volume of silica gel, the concentration of which is adjusted so that the concentration of the platinum metal when supported is 3%, and is dried. Leave the last one without doing anything. Up to this point, the first stage in Table 2 has produced three types of catalysts including the carrier alone.
Samples for evaluation are extracted from each of these three portions by 0.1 g, and the remainder is mixed well and divided into three. One portion of this is oxidized after supporting cerium nitrate, and then dissolved in an amount of cerium oxide corresponding to 5% of the carrier in water slightly smaller than the silica gel pore volume, impregnated, and dried. In the other part, after oxidation after supporting iron nitrate, an amount corresponding to 5% of the support as iron oxide is dissolved in an amount of water slightly smaller than the silica gel pore volume, impregnated, and dried. The other one is left unprocessed. This is the second stage in Table 2, and nine types of catalysts including the carrier have been generated. From each of these three parts, 0.1 g of the sample for evaluation is extracted, and the remainder is mixed well and again divided into three equal parts. One of them is zirconyl nitrate, which is oxidized after loading, and then dissolved in a quantity of water equivalent to 5% of the support as zirconium oxide in water slightly smaller than the pore volume, impregnated and dried. Next, this was calcined at 350 ° C., and then hydrogen reduced at the same temperature to obtain about 1 g of catalyst (this is referred to as CAT-Zr). In the other part, an amount equivalent to 3% of the support as sodium oxide of sodium nitrate is dissolved in an amount of water slightly smaller than the pore volume, impregnated and dried. Next, this was calcined at 350 ° C., and then reduced with hydrogen at the same temperature to obtain about 1 g of catalyst (this is referred to as CAT-Na). The remaining one was calcined at 350 ° C. without any treatment, and then reduced with hydrogen at the same temperature to obtain about 1 g of catalyst (this is designated as CAT-REF1). Up to this point, the 27th catalyst including the carrier has been produced in the third stage of Table 2. Subsequently, the samples extracted in the first stage and the second stage were also fired and reduced in the same manner. (Pd-SiO2, Pt-SiO2, SiO2, MOD-Ce, MOD-Fe, and MOD-REF0, respectively)
0.1 g of the catalyst prepared by the above method was mixed with 0.1 g of silica gel, charged in a normal pressure flow reactor for evaluating the activity of the catalyst, hydrogen reduced at 250 ° C. for 1 hour and cooled to 150 ° C. Thereafter, a mixed gas of methanol: helium: argon = 2: 93: 5 was supplied at a rate of 200 ml / min. The catalyst layer temperature was maintained at 150 ° C. for 1 hour and then increased to 175 ° C., and the catalyst layer temperature was maintained at 150, 175, 200, 225 and 250 ° C. for 1 hour, and held at each temperature for 1 hour. The product gas was sampled and analyzed. More than 97% of the reaction products were carbon monoxide and hydrogen. This operation was repeated at methanol concentrations of 2, 4, 10, and 20%. Table 1 shows the carbon monoxide yield (CO yield) (mmol / gram catalyst per hour) when the reaction was conducted at a methanol concentration of 20% and a temperature of 200 ° C.
A summary of the preparation procedure and the produced catalyst in Example 1 is shown in Table 2 for reference. () In Table 2 indicates the type of catalyst produced.
[0033]
Example 2
The operating procedure of Example 2 is shown in Table 3 (however, Table 3 does not show the type of catalyst contained in the mixture).
A new 6 g of silica gel is taken, and this is divided into 3 parts, and Zr or Na is supported as the first stage by the same method as described in Example 1, and the three are mixed well without any treatment, and divided into 2 parts. One of them is further divided into three.
In each of the three divided parts, Ce or Fe is carried as the second stage in the same manner as in Example 1, and a part is left untreated, mixed in the same manner as described above, and then divided into three. As the third stage, Pd or Pt is supported on each part, and a part is left untreated. Each was calcined at 350 ° C. in the same manner as the catalyst, and then reduced with hydrogen at the same temperature to obtain about 1 g of each catalyst. Let each be CAT-Pd, CAT-Pt, and CAT-REF2.
Next, the remaining part that has been divided into two parts after the first stage support is further divided into three parts. Contrary to the above-described order, Pd or Pt is supported in the second stage, then Ce or Fe is supported in the third stage, and one part is left untreated at 350 ° C. in the same manner as the catalyst. After baking, hydrogen reduction was performed at the same temperature to obtain about 1 g of each catalyst. Let each be CAT-Ce, CAT-Fe, and CAT-REF3. The reaction characteristics of the catalyst thus obtained were evaluated in the same manner as in Example 1. The results are shown in Table 1.
The components used in CAT-Zr, CAT-Na, and CAT-REF1 of Example 1 and CAT-Pd, CAT-Pt, CAT-REF2, and CAT-Ce, CAT-Fe, and CAT-REF3 of Example 2 were used. All of the catalysts supported at the final stage and their raw material catalysts were prepared and evaluated.
[0034]
Comparative Example 1
The multi-component catalyst contained in the catalyst shown in Example 1 is a carrier SiO2, Pd / SiO2, Pt / SiO2, Ce / Pd / SiO2, Ce / Pt / SiO2, Fe / Pd / SiO2, Fe / Pt / SiO2, Zr. / Ce / Pd / SIO2, Zr / Ce / Pt / SiO2, Zr / Fe / Pd / SiO2, Zr / Fe / Pt / SiO2, Na / Ce / Pd / SiO2, Na / Ce / Pt / SiO2, Na / Fe 27 types including / Pd / SiO2, Na / Fe / Pt / SiO2, but here, for comparison, Pd / SiO2, Pt / SiO2, Pd / Ce / SiO2, Pd / Na / SiO2, Pd / Zr / SiO2 was prepared. Pt (3%)-SiO2 is the same method as Example 1, and Pd (3%)-SiO2 is the same method as Example 1 except that the firing is omitted. Pd (3%)-Na (3% ) -SiO2, Pd-SiO2 is impregnated later with sodium nitrate and reduced to reduce Pd (3%)-Ce (5%)-SiO2 and Pd (3%)-Zr (5%)-SiO2. Was previously loaded with cerium oxide or zirconium oxide on silica gel, impregnated with a palladium chloride solution, dried and then reduced with hydrogen to obtain a catalyst. For Pd—Na—SiO 2, the reaction performance was evaluated in the same manner as in Example 1 except that the catalyst amount was 0.2 g and silica gel was not added. The results at a methanol concentration of 4% and a reaction temperature of 200 ° C. are shown in Table 1.
[0035]
Comparative Example 2
After loading palladium chloride, platinum ammonium nitrate, iron chloride, cerium nitrate, zirconyl nitrate, and sodium nitrate, the metal or oxide is taken to be 3%, 3%, 5%, 5%, 5%, and 3%. It was dissolved in approximately the same amount of water as the pore volume and impregnated and supported on silica gel. After drying, firing at 350 ° C. and hydrogen reduction at the same temperature gave a catalyst. 0.1 g of this was taken, and the reaction performance was evaluated by the same method as in Example 1. The results at a methanol concentration of 20% and a reaction temperature of 200 ° C. are shown in Table 1.
[0036]
[Table 1]

[0037]
[Table 2]

[0038]
[Table 3]

[0039]
[Consideration of experimental results]
Considering that the activity of MOD-REF0 of Example 1 shown in Table 1 is almost equal to the sum of the activities of Pd-SiO2 and Pt-SiO2, and that the other mixed SiO2 has no activity. It can be seen that the addition of the activity of each catalyst is almost established here, with no particular change caused by mixing.
When the reaction performance evaluation results of three cases of CAT-Zr, CAT-Na, and CAT-REF1 of Example 1 shown in Table 1 are seen, the activity of those treated with Zr is greatly increased as compared with the untreated CAT-REF1. , Na treated with Na was found to have decreased activity, suggesting the presence of an effective catalyst and Zr as an active ingredient. This result is consistent with the effectiveness of Zr and the interference with Na seen in Comparative Example 1 prepared by different methods. If only the presence or absence of such an active catalyst is examined, usually 26 evaluations are made. This case shows that the results can be obtained with only 3 evaluations. Furthermore, effective knowledge has been obtained regarding the effects of catalyst components such as Zr and Na, confirming the effectiveness of the method of the present invention.
[0040]
After the presence of an effective catalyst was clarified, the samples (Pd—SiO 2, Pt—SiO 2, SiO 2, MOD—Ce, MOD—Fe obtained in the first step and the second step shown in Example 1 were used. , MOD-REF0) and comparing it with the untreated one, the effectiveness of Ce and Pd is suggested, and the Zr · Ce · Pd / SiO 2 system will be raised as a detailed investigation candidate catalyst. Even in this case, it is possible to narrow down the catalyst with a small number of steps.
Furthermore, when it is desired to clarify the active ingredient that improves the activity, the preparation shown in Example 2 was conducted after evaluation of three cases (CAT-Zr, CAT-Na, CAT-REF1) in Example 1 in which the effectiveness was confirmed. By performing the method, the components processed in the final stage, that is, the third stage, cover all the components used in the preparation, and in the final stage of Example 1, the effectiveness of Zr and the interference of Na were observed. Similarly, from the comparison of CAT-Pd, CAT-Pt, and CAT-REF2 in Table 1, the activity is Pd> Pt, Pd or Pt is essential as a catalyst component, and the effects of Ce and Fe are also found. The effectiveness of these components becomes almost clear, and the composition of the effective catalyst can be estimated. However, in this case, the number of samples to be evaluated is (total number of components + number of processing stages), and it is not particularly effective when the number of components is small and the number of processing stages is small, but it is effective when the number of components and the number of processing stages increases. Method.
[0041]
The relationship between the number of reaction performance evaluation experiments required for evaluation and the search method is such that all components are different, each stage has the same number of components, the number of single-stage components is m, and the number of combination stages is r. The values are as follows:

[0042]
When actually calculated, the relationship between the required number of reaction performance evaluation experiments and the search method is as follows, and the effectiveness of the present invention when the number of components and the number of combination stages is large is demonstrated.

[0043]
In the catalyst in which the components of the catalyst were mixed from the beginning, as shown in Comparative Example 2, the activity was 2/3 of the total activity of Pd—SiO 2 and Pt—SiO 2, which was lower than the activity of the metal alone, This method is not suitable for catalyst search because the existence of a highly active catalyst such as Pd—Zr—SiO 2 cannot be estimated.
[0044]
【The invention's effect】
According to the method of the present invention, a catalyst group composed of a set of predetermined solid catalyst particles is prepared in advance, and then the effectiveness of the solid catalyst contained in the catalyst group is determined for each individual solid catalyst constituting the catalyst group. An effective multi-component solid catalyst can be searched quickly only by discriminating without separate separation. Therefore, compared with the conventional method in which a multi-component solid catalyst is prepared individually and the effectiveness of the catalyst is determined each time, the presence or absence of an effective catalyst within the search range is evaluated based on a very small number of reaction performance evaluations. Thus, it is possible to dramatically and rapidly search for an effective combination of effective catalyst components.

Claims

A method for rapidly searching a multi-component solid catalyst comprising a plurality of solid catalyst components, comprising a catalyst preparation method in which each catalyst component is supported stepwise on a support. In the first step, the support is added in the first step. Divide into parts with the number of catalyst components to be loaded + 1 and leave one of them untreated, and load the other parts with different catalyst components and mix them all, including the untreated parts. In the second stage, the mixture is divided into the number of catalyst components +1 to be supported in the second stage, one of them is left untreated, and the other parts are different from each other in the same manner as in the first stage. By carrying the components and repeating the same operation from the third stage to the necessary stage, a catalyst group consisting of various multi-element solid catalyst particles is prepared, and then the effectiveness of the solid catalyst contained in the catalyst group is improved. Configure the catalyst group Quick method of searching multi-component solid catalyst and evaluating without separating into each other in the people of the solid catalyst.

2. The rapid search method for a multi-component solid catalyst according to claim 1, wherein the catalyst component is supported by an impregnation method.

The rapid search method for a multi-component solid catalyst according to claim 2, wherein the amount of the solution in the impregnation method is less than the pore volume of the support.

Evaluate the catalyst group at the final stage to determine the effective catalyst group, and continue to conduct the same evaluation on the effectiveness of the catalyst group prepared in the previous stage. The rapid search method for a multi-component solid catalyst according to any one of claims 1 to 3, wherein the method is traced as far as possible.

Use the catalyst group obtained by changing the loading order of the catalyst components and loading all the catalyst components once in the final stage, and in each case, only the catalyst group obtained in the final stage is effective. The rapid search method for a multi-component solid catalyst according to any one of claims 1 to 3, wherein the evaluation is made in comparison with an untreated one.