JP4465731B2 - Method for producing ε-caprolactam - Google Patents
Method for producing ε-caprolactam Download PDFInfo
- Publication number
- JP4465731B2 JP4465731B2 JP05556399A JP5556399A JP4465731B2 JP 4465731 B2 JP4465731 B2 JP 4465731B2 JP 05556399 A JP05556399 A JP 05556399A JP 5556399 A JP5556399 A JP 5556399A JP 4465731 B2 JP4465731 B2 JP 4465731B2
- Authority
- JP
- Japan
- Prior art keywords
- caprolactam
- acid
- cyclohexanone oxime
- catalyst
- amorphous silica
- Prior art date
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- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims description 46
- 238000004519 manufacturing process Methods 0.000 title claims description 11
- VEZUQRBDRNJBJY-UHFFFAOYSA-N cyclohexanone oxime Chemical compound ON=C1CCCCC1 VEZUQRBDRNJBJY-UHFFFAOYSA-N 0.000 claims description 58
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 57
- 239000011949 solid catalyst Substances 0.000 claims description 19
- 238000006243 chemical reaction Methods 0.000 claims description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 15
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 11
- 125000004432 carbon atom Chemical group C* 0.000 claims description 3
- 125000002723 alicyclic group Chemical group 0.000 claims 1
- 125000001931 aliphatic group Chemical group 0.000 claims 1
- 238000010574 gas phase reaction Methods 0.000 claims 1
- 239000003054 catalyst Substances 0.000 description 24
- 229910052814 silicon oxide Inorganic materials 0.000 description 19
- 239000007789 gas Substances 0.000 description 14
- 239000012071 phase Substances 0.000 description 14
- 238000006237 Beckmann rearrangement reaction Methods 0.000 description 13
- 239000002253 acid Substances 0.000 description 13
- 238000000034 method Methods 0.000 description 13
- 229910021536 Zeolite Inorganic materials 0.000 description 11
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 11
- 239000010457 zeolite Substances 0.000 description 11
- 239000007864 aqueous solution Substances 0.000 description 10
- 230000000052 comparative effect Effects 0.000 description 10
- 238000010306 acid treatment Methods 0.000 description 9
- 239000000377 silicon dioxide Substances 0.000 description 8
- 229910004298 SiO 2 Inorganic materials 0.000 description 7
- 230000002378 acidificating effect Effects 0.000 description 7
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 7
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 6
- 230000000694 effects Effects 0.000 description 6
- 125000005372 silanol group Chemical group 0.000 description 6
- 239000000203 mixture Substances 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 3
- 238000006555 catalytic reaction Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000002243 precursor Substances 0.000 description 3
- 238000006462 rearrangement reaction Methods 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- AMQJEAYHLZJPGS-UHFFFAOYSA-N N-Pentanol Chemical compound CCCCCO AMQJEAYHLZJPGS-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 2
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- BTANRVKWQNVYAZ-UHFFFAOYSA-N butan-2-ol Chemical compound CCC(C)O BTANRVKWQNVYAZ-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 239000008367 deionised water Substances 0.000 description 2
- 229910021641 deionized water Inorganic materials 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- ZSIAUFGUXNUGDI-UHFFFAOYSA-N hexan-1-ol Chemical compound CCCCCCO ZSIAUFGUXNUGDI-UHFFFAOYSA-N 0.000 description 2
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 description 2
- 150000007522 mineralic acids Chemical class 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- 229910002027 silica gel Inorganic materials 0.000 description 2
- 239000000741 silica gel Substances 0.000 description 2
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- 238000001157 Fourier transform infrared spectrum Methods 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 1
- QXAITBQSYVNQDR-UHFFFAOYSA-N amitraz Chemical compound C=1C=C(C)C=C(C)C=1N=CN(C)C=NC1=CC=C(C)C=C1C QXAITBQSYVNQDR-UHFFFAOYSA-N 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000002425 crystallisation Methods 0.000 description 1
- 230000008025 crystallization Effects 0.000 description 1
- 238000004821 distillation Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000005342 ion exchange Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 150000003856 quaternary ammonium compounds Chemical class 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- LIVNPJMFVYWSIS-UHFFFAOYSA-N silicon monoxide Chemical class [Si-]#[O+] LIVNPJMFVYWSIS-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- HIFJUMGIHIZEPX-UHFFFAOYSA-N sulfuric acid;sulfur trioxide Chemical compound O=S(=O)=O.OS(O)(=O)=O HIFJUMGIHIZEPX-UHFFFAOYSA-N 0.000 description 1
- 238000005979 thermal decomposition reaction Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts
Description
【0001】
【発明の属する技術分野】
本発明は、固体触媒存在下、気相状態のシクロヘキサノンオキシムのベックマン転位反応によるε−カプロラクタムの製造用固体触媒およびこれを用いてなるε−カプロラクタムの製造方法に関する。
【0002】
【従来の技術】
ε−カプロラクタムはナイロン等の重要な原料であり、現在、工業的には発煙硫酸または濃硫酸を使ってシクロヘキサノンオキシムを液相においてベックマン転位させる方法で主として製造されている。この方法の欠点は硫酸を中和するためにアンモニアを必要とし、ε−カプロラクタム1トン当たり約1.7トンの硫酸アンモニウムが副生することである。
【0003】
デュポン社がシクロヘキサノンオキシム蒸気を約200℃〜500℃の温度でシリカゲル等の触媒に流通させる方法を提案(米国特許第2234566号公報)して以来、望まれない副生成物である硫酸アンモニウムの発生を避けるために、固体触媒の存在下でのシクロヘキサノンオキシムの気相ベックマン転位反応を達成するための数々の努力が払われてきた。
【0004】
これらに適用される固体触媒としては、例えば、ホウ酸触媒(ドイツ特許第2641381号公報、ドイツ特許第1195318号公報等)、シリカアルミナ触媒(英国特許第831972号公報)、固体リン酸触媒(英国特許第881926号公報)、結晶性ゼオライト触媒(ジャーナル オブ キャタリシス、6巻、247頁、1966年、米国特許第4359421号公報、米国特許第4709024号公報)等が提案されている。
【0005】
【発明が解決しようとする課題】
しかしながら、これら触媒はそれぞれ優れた活性、選択性を有するものの触媒の製造方法が複雑であったり高価であることより、本発明者等は、廉価で入手しやすい固体触媒を見出すべく鋭意検討した結果、従来シクロヘキサノンオキシムの気相ベックマン転位反応によるε−カプロラクタム生成には不満足な触媒活性しか示さないと考えられていた酸化ケイ素、通常、非晶質シリカに特定の処理を行う場合には、廉価で且つ 活性に優れた触媒となし得ることを見出し、本発明を完成するに至った。
【0006】
【課題を解決するための手段】
即ち、本発明は固体触媒の存在下、シクロヘキサノンオキシムの気相ベックマン転位反応によるε−カプロラクタムを製造する方法において、固体触媒としてpHが1〜6である酸性水溶液で処理してなる酸化ケイ素を用いることを特徴とするε−カプロラクタムの製造方法を提供するものである。
さらに本発明は酸化ケイ素がビシナルシラノールを有することを特徴とする気相ベックマン転位に使用するための固体触媒を提供するものである。
【0007】
【発明の実施の形態】
以下、本発明方法を更に詳細に説明する。
本発明方法の実施に際しては、気相ベックマン転位反応に固体触媒としてpHが1〜6である酸性水溶液で処理してなる酸化ケイ素を用いる。
【0008】
前記酸化ケイ素としては、通常、非晶質シリカ単独、あるいは非晶質シリカを含有する物質、具体例としては気相ベックマン転位反応に使用される公知の触媒構成物質、例えばゼオライトやシリカアルミナ等と非晶質シリカを混合してなる非晶質シリカ含有物質等が挙げられる。酸化ケイ素としては触媒としての適用時に酸化ケイ素であればよく、製造方法や前駆形態は特に問わない。それゆえ、市販の非晶質シリカの他、シリカゾルやシリカゲルなどを酸化ケイ素の前駆体として適用することもできる。
【0009】
非晶質シリカと混合して用いる他の物質がゼオライトの場合、これに使用し得るゼオライトとしては、例えばMFI、MEL及びBEAが挙げられる。ゼオライトはSi/Me原子比が50またはそれ以上、好ましくは500以上である。ここでMeはB、Al、Ga、Fe、Ti及びZrからなる郡より選ばれた少なくとも1種の金属である。尚、Me/Si原子比は、原子吸光分析、蛍光X線分析及びその他方法により測定することができる。
ゼオライトの製造方法は特に制限されるものではないが、例えばシリカ源、水、第4級アンモニウム化合物必要に応じて金属源の混合物をオートクレーブ中で水熱合成反応した後、得られた結晶を焼成し、アンモニウム塩等の水溶液でイオン交換し、乾燥し、次いで、得られた乾燥品に非晶質シリカの前駆体(例えば、シリカゾル)を添加混合した後、成形、乾燥する方法等が挙げられる。尚、非晶質シリカの添加量は、特に制限されるものではなく、廉価な触媒を供給することを主目的とする場合には、非晶質シリカ量を多量に、触媒としてのゼオライトの特性を生かす場合にはゼオライトを多量に用いればよく、具体的にはゼオライトに対し非晶質シリカの添加量は約0.1重量倍〜約10重量倍である。
【0010】
本発明において、酸化ケイ素の酸処理方法は、特に制限されるものではなく、処理対象物である酸化ケイ素全体が十分に酸性水溶液中で酸と接触できる方法であればよく、容器中に酸化ケイ素を投入し、次いでこの容器中に酸性水溶液を注ぎ、攪拌下に浸漬する方法、あるいはカラム等に充填した状態で酸性水溶液を通過させる方法等が挙げられる。より具体的な一方法としては、例えば非晶質シリカ等の酸化ケイ素を酸、好ましくは無機酸の水溶液と混合し、得られた混合物を温度約20℃〜約100℃で約1時間〜約50時間リフラックスした後、固体触媒を濾過し、脱イオン水により洗浄し、約100℃で約1〜10時間乾燥する方法で行えばよい。無機酸としては塩酸、フッ酸、硫酸又は硝酸が挙げられ、就中、塩酸の使用が推奨される。酸のpHは約1〜約6、好ましくは約1.5〜約3、最適には約2である。酸のpHが約1より低い場合には、得られる固体触媒を気相ベックマン転位反応に適用した時、シクロヘキサノンオキシムの転化率が低下する傾向にある。酸のpHが約6より高い場合には、得られる固体触媒を気相ベックマン転位反応に適用した時、ε−カプロラクタムの選択率が低下する傾向にある。
【0011】
酸処理に付す酸化ケイ素は、粉末或いは触媒としての所望形状に成形した成形体のいずれであってもよい。また、担体上にこれら酸化ケイ素を被覆し触媒として適用してもよい。尚、本明細書において酸化ケイ素なる表現は特に断りのない限り非晶質シリカ単独および非晶質シリカとゼオライトの他、シリカ・アルミナ等の気相ベックマン転位反応用触媒として公知の触媒構成物質を混合した非晶質シリカ含有物質を包含するものである。
【0012】
このようにして得られた酸処理後の酸化ケイ素は、通常の固体触媒と同様に、シクロヘキサノンオキシムの転位反応に供される。
反応は通常公知の固定床方式または流動床方式の気相接触反応により行う。原料シクロヘキサノンオキシムは気体状態で触媒層に導入される。反応温度は通常約250℃〜約450℃の範囲である。温度が約250℃未満の場合には、反応速度が十分ではなく、かつε−カプロラクタムの選択性も低下する傾向がある。一方、温度が約450℃を超えるとシクロヘキサノンオキシムの熱分解が無視できなくなり、ε−カプロラクタムの選択率が低下する傾向がある。特に、好ましい温度範囲は約300℃〜約400℃である。また反応圧力は特に限定されるものではなく、通常約5kPa〜約10MPa、好ましくは約5kPa〜0.5MPaである。
【0013】
原料シクロヘキサノンオキシムの空間速度は、通常WHSV=約0.1h−1〜約20h−1、(すなわち触媒1kg当たりのシクロヘキサノンオキシムの供給速度が約0.1kg/h〜約20kg/h)、好ましくは約0.2h−1〜約10h−1の範囲から選ばれる。
【0014】
またシクロヘキサノンオキシムの転位反応に際し、反応系にシクロヘキサノンオキシムとともに炭素数1〜6の低級アルコールを共存させることも可能である。炭素数1〜6の低級アルコールとしては、例えばメタノール、エタノール、n−プロパノール、イソプロパノール、n―ブタノール、sec―ブタノール、イソブタノール、n−アミルアルコール、n−ヘキサノール、等が挙げられ、こららの1種または2種以上が用いられる。中でもメタノール、エタノールの使用が推奨される。
低級アルコールを用いる場合、その存在量はシクロヘキサノンオキシムに対して重量比で、通常約0.1〜約20倍が適当であり、好ましくは約0.2〜約10倍の範囲がよい。
これら低級アルコールの使用はε―カプロラクタムの選択率および触媒寿命に効果を示す。
【0015】
反応混合物からのεーカプロラクタムの分離は、通常の方法で実施できる。例えば、反応生成ガスを冷却して凝縮させ、次いで抽出、蒸留あるいは晶析等により精製されたεーカプロラクタムを効率的に製造できる。
【0016】
従来、酸化ケイ素(シリカ)はそのままでは十分な活性がなく、シクロヘキサノンオキシムの気相ベックマン転位反応によるε−カプロラクタム製造用の固体触媒として適していないことが知られていた(Hoelderich,W.F.,Roesler,J.,Heitmann,G.,Liebens,A.T.,キャタリシス ツディ 37巻,353頁,1997年,表4)。しかしながら、上記した如く、本発明者らは酸化ケイ素を希塩酸等の酸で処理する場合には、それをシクロヘキサノンオキシムの気相ベックマン転位反応用触媒として使用した場合、シクロヘキサノンオキシムの転化率やε−カプロラクタムの選択性が向上することを見出したものである。
【0017】
この活性化作用が発現するメカニズムについては、非晶質シリカをpHが1〜6である酸性水溶液で処理することにより、該非晶質シリカ表面のケイ素原子が一部取り除かれ、表面に多くの新しいシラノール基[ビシナルシラノール(vicinal silanol)]が生成することに起因するものと考える。このことは、本発明者等が、酸で処理していないSiO2物質(比較例2で用いた非晶質シリカ)と、実施例2の酸処理したSiO2とをFT−IRで分析したところ、図1に示す如く、いずれのスペクトルにも、シリカ表面のシラノール基に関連する3740cm−1近傍に鋭いピークが見られるが酸処理を行ったSiO2は、酸処理なしのSiO2には見られないビシナルシラノールを表す3680cm−1近傍に著しく大きなピークが見られることより、酸処理によるこのビシナルシラノールの発現がSiO2表面の新しい活性点となって触媒性能の向上に寄与しているものと考察する次第である。
【0018】
【発明の効果】
以上詳述した如く、本発明は単に特定濃度の酸性水溶液で処理するという極めて簡単な操作で、従来シクロヘキサノンオキシムの気相ベックマン転位反応によるε−カプロラクタムの製造用固体触媒としてはわずかな触媒活性しか示さないと考えられていた非晶質シリカを、廉価で且つ 活性に優れた触媒となし得ることを見出したもので、その産業上の効果は極めて大なるものである。
【0019】
【実施例】
本発明を実施例により更に詳細に説明するが、本発明は以下の実施例により制限されるものではない。
【0020】
比較例1
非晶質シリカ(商品名:D11−10、BASF社製)5gと1M塩酸100gとを混合し、得られた混合物を100℃で24時間リフラックスすることによって酸処理した後、濾過して、シリカを得た。得られたシリカを脱イオン水で洗浄し、110℃で4時間乾燥し、固体触媒を得た。
【0021】
このようにして得た固体触媒1.5gを内径6mmの管型反応器に充填し(高さ約40mm)、これにシクロヘキサノンオキシムに対し溶媒としてエタノールを9重量倍混合した溶液を予備蒸発器にて気化し、キャリヤーガスと混合して、反応管に供給して反応させた。この時のシクロヘキサノンオキシムの空間速度WHSVは0.33h−1であり、触媒層の温度(反応温度)は300℃、反応圧力は10kPaであった。反応生成物は液体窒素で冷却した低温トラップに捕集した後、解凍してガスクロマトグラフィーにより分析した。その結果、転化率は20.2%であり、選択率は78.8%であった。
【0022】
尚、ここにシクロヘキサノンオキシムの空間速度WHSVは次式で算出し、またシクロヘキサノンオキシムの転化率およびε−カプロラクタムの選択率もそれぞれ次式で算出した。
WHSV(hr−1)=O/C
シクロヘキサノンオキシムの転化率(%)=[(X−Y)/X]×100
ε−カプロラクタムの選択率(%)=[Z/(X−Y)]×100
また、O、C、X、YおよびZはそれぞれ次の通りとおりである。
O=シクロヘキサノンオキシム供給速度(kg/hr)
C=触媒重量(kg)
X=供給した原料シクロヘキサノンオキシムのモル数
Y=未反応のシクロヘキサノンオキシムのモル数
Z=生成物中のε−カプロラクタムのモル数
【0023】
実施例2−3、比較例3(旧実施例1)、比較例4(旧実施例4)
比較例1において、酸処理時の酸濃度を表1に示す様に変えた以外は同様にして行った。その結果を表1に示す。
【0024】
【表1】
【0025】
比較例2
比較例1において、塩酸水溶液による処理を行わなかった以外は比較例1と同様にしてシクロヘキサノンオキシムの転位反応を行った。その結果、転化率は12.8%であり、選択率は65.4%であった。
【0026】
実施例5
実施例2において、酸処理の温度100℃を40℃に変えた以外は実施例2と同様にして行った。その結果、転化率は35.7%であり、選択率は70.5%であった。
【0027】
比較例5(旧実施例6)
実施例2において、酸処理に用いた塩酸を硫酸に変えた以外は実施例2と同様にして行った。その結果を表2に示す。
【0028】
比較例6(旧実施例7)
実施例2において、酸処理に用いた塩酸を硝酸に変えた以外は実施例2と同様にして行った。その結果を表2に示す。
【0029】
【表2】
【図面の簡単な説明】
【図1】 本発明方法の酸水溶液で処理した酸化ケイ素SiO2(酸処理)と未処理の酸化ケイ素SiO2(未処理)のFT−IRスペクトルを示す。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a solid catalyst for producing ε-caprolactam by Beckmann rearrangement reaction of cyclohexanone oxime in a gas phase in the presence of a solid catalyst, and a method for producing ε-caprolactam using the same.
[0002]
[Prior art]
ε-Caprolactam is an important raw material such as nylon, and is currently produced mainly in the industry by a method in which cyclohexanone oxime is rearranged in the liquid phase using fuming sulfuric acid or concentrated sulfuric acid. The disadvantage of this method is that ammonia is required to neutralize the sulfuric acid and about 1.7 tons of ammonium sulfate is by-produced per ton of ε-caprolactam.
[0003]
Since DuPont proposed a method of circulating cyclohexanone oxime vapor through a catalyst such as silica gel at a temperature of about 200 ° C. to 500 ° C. (US Pat. No. 2,234,566), generation of ammonium sulfate, an unwanted by-product, has been generated. To avoid, numerous efforts have been made to achieve the gas phase Beckmann rearrangement reaction of cyclohexanone oxime in the presence of a solid catalyst.
[0004]
Examples of the solid catalyst applied to these include a boric acid catalyst (German Patent No. 2641381, German Patent No. 1195318, etc.), a silica alumina catalyst (UK Patent No. 831972), and a solid phosphoric acid catalyst (UK). Patent No. 881926), crystalline zeolite catalyst (Journal of Catalysis, Vol. 6, p. 247, 1966, U.S. Pat. No. 4,359,421, U.S. Pat. No. 4,709,024) have been proposed.
[0005]
[Problems to be solved by the invention]
However, although these catalysts have excellent activity and selectivity, the method for producing the catalysts is complicated and expensive. As a result, the present inventors have intensively studied to find an inexpensive and easily obtainable solid catalyst. However, silicon oxide, which was previously considered to have only unsatisfactory catalytic activity for the formation of ε-caprolactam by the gas phase Beckmann rearrangement reaction of cyclohexanone oxime, is usually inexpensive when performing specific treatment on amorphous silica. In addition, the present inventors have found that the catalyst can be excellent in activity and have completed the present invention.
[0006]
[Means for Solving the Problems]
That is, the present invention uses silicon oxide treated with an acidic aqueous solution having a pH of 1 to 6 as a solid catalyst in a method for producing ε-caprolactam by a gas phase Beckmann rearrangement reaction of cyclohexanone oxime in the presence of a solid catalyst. A method for producing ε-caprolactam is provided.
Furthermore, the present invention provides a solid catalyst for use in gas phase Beckmann rearrangement characterized in that silicon oxide has vicinal silanol.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the method of the present invention will be described in more detail.
In carrying out the method of the present invention, silicon oxide formed by treatment with an acidic aqueous solution having a pH of 1 to 6 is used as a solid catalyst in the gas phase Beckmann rearrangement reaction.
[0008]
As the silicon oxide, usually amorphous silica alone or a substance containing amorphous silica, specifically, a known catalyst constituent used for gas phase Beckmann rearrangement reaction, such as zeolite and silica alumina, etc. Examples thereof include amorphous silica-containing materials obtained by mixing amorphous silica. The silicon oxide may be silicon oxide at the time of application as a catalyst, and the production method and precursor form are not particularly limited. Therefore, in addition to commercially available amorphous silica, silica sol, silica gel, or the like can be applied as a precursor of silicon oxide.
[0009]
When the other substance used by mixing with amorphous silica is zeolite, examples of zeolite that can be used for this include MFI, MEL, and BEA. Zeolite has a Si / Me atomic ratio of 50 or more, preferably 500 or more. Here, Me is at least one metal selected from the group consisting of B, Al, Ga, Fe, Ti and Zr. The Me / Si atomic ratio can be measured by atomic absorption analysis, fluorescent X-ray analysis, and other methods.
The method for producing the zeolite is not particularly limited. For example, a mixture of a silica source, water, and a quaternary ammonium compound is optionally hydrothermally reacted in an autoclave, and then the obtained crystals are calcined. Then, ion exchange is performed with an aqueous solution of an ammonium salt and the like, followed by drying. Then, a precursor of amorphous silica (for example, silica sol) is added to and mixed with the obtained dried product, followed by molding and drying. . The amount of amorphous silica added is not particularly limited. When the main purpose is to supply an inexpensive catalyst, the amount of amorphous silica is large, and the characteristics of the zeolite as a catalyst. In order to make the best use of the zeolite, a large amount of zeolite may be used. Specifically, the amount of amorphous silica added is about 0.1 to about 10 times by weight to the zeolite.
[0010]
In the present invention, the acid treatment method of silicon oxide is not particularly limited, and any method can be used as long as the entire silicon oxide as a treatment target can be sufficiently brought into contact with an acid in an acidic aqueous solution. Then, an acidic aqueous solution is poured into this container and immersed in stirring, or a method of passing the acidic aqueous solution in a state where it is packed in a column or the like. As a more specific method, for example, silicon oxide such as amorphous silica is mixed with an aqueous solution of an acid, preferably an inorganic acid, and the resulting mixture is heated at a temperature of about 20 ° C. to about 100 ° C. for about 1 hour to about 100 ° C. After refluxing for 50 hours, the solid catalyst may be filtered, washed with deionized water, and dried at about 100 ° C. for about 1 to 10 hours. Examples of inorganic acids include hydrochloric acid, hydrofluoric acid, sulfuric acid, and nitric acid, and the use of hydrochloric acid is recommended. The pH of the acid is about 1 to about 6, preferably about 1.5 to about 3, and optimally about 2. When the pH of the acid is lower than about 1, when the obtained solid catalyst is applied to the gas phase Beckmann rearrangement reaction, the conversion of cyclohexanone oxime tends to decrease. When the pH of the acid is higher than about 6, the selectivity of ε-caprolactam tends to decrease when the obtained solid catalyst is applied to the gas phase Beckmann rearrangement reaction.
[0011]
The silicon oxide to be subjected to the acid treatment may be either a powder or a molded body formed into a desired shape as a catalyst. Further, these silicon oxides may be coated on a support and applied as a catalyst. In the present specification, unless otherwise specified, the expression silicon oxide represents amorphous silica alone, amorphous silica and zeolite, as well as catalyst constituents known as catalysts for gas phase Beckmann rearrangement reactions such as silica and alumina. Including mixed amorphous silica-containing material.
[0012]
The acid-treated silicon oxide thus obtained is subjected to a cyclohexanone oxime rearrangement reaction in the same manner as an ordinary solid catalyst.
The reaction is usually carried out by a known fixed bed type or fluidized bed type gas phase catalytic reaction. The raw material cyclohexanone oxime is introduced into the catalyst layer in a gaseous state. The reaction temperature is usually in the range of about 250 ° C to about 450 ° C. When the temperature is less than about 250 ° C., the reaction rate is not sufficient, and the selectivity of ε-caprolactam tends to decrease. On the other hand, when the temperature exceeds about 450 ° C., thermal decomposition of cyclohexanone oxime cannot be ignored, and the selectivity of ε-caprolactam tends to decrease. In particular, the preferred temperature range is from about 300 ° C to about 400 ° C. The reaction pressure is not particularly limited, and is usually about 5 kPa to about 10 MPa, preferably about 5 kPa to 0.5 MPa.
[0013]
The space velocity of the raw material cyclohexanone oxime is usually WHSV = about 0.1 h −1 to about 20 h −1 (that is, the supply rate of cyclohexanone oxime per kg of catalyst is about 0.1 kg / h to about 20 kg / h), preferably It is selected from the range of about 0.2 h −1 to about 10 h −1 .
[0014]
In the rearrangement reaction of cyclohexanone oxime, a lower alcohol having 1 to 6 carbon atoms can coexist with the cyclohexanone oxime in the reaction system. Examples of the lower alcohol having 1 to 6 carbon atoms include methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, n-amyl alcohol, n-hexanol, and the like. 1 type (s) or 2 or more types are used. Of these, methanol and ethanol are recommended.
When a lower alcohol is used, its abundance is usually from about 0.1 to about 20 times, preferably from about 0.2 to about 10 times the weight ratio of cyclohexanone oxime.
Use of these lower alcohols has an effect on ε-caprolactam selectivity and catalyst life.
[0015]
Separation of ε-caprolactam from the reaction mixture can be carried out by a usual method. For example, the reaction product gas can be cooled and condensed, and then ε-caprolactam purified by extraction, distillation or crystallization can be efficiently produced.
[0016]
Conventionally, it has been known that silicon oxide (silica) does not have sufficient activity as it is and is not suitable as a solid catalyst for the production of ε-caprolactam by the gas phase Beckmann rearrangement reaction of cyclohexanone oxime (Hoelderich, WF, Roesler, J., Heitmann, G., Liebens, AT, Catalysis Tudy 37, 353, 1997, Table 4). However, as described above, when the present inventors treat silicon oxide with an acid such as dilute hydrochloric acid, when it is used as a catalyst for the gas phase Beckmann rearrangement reaction of cyclohexanone oxime, the conversion rate of cyclohexanone oxime or ε- It has been found that the selectivity of caprolactam is improved.
[0017]
Regarding the mechanism by which this activation action is expressed, by treating amorphous silica with an acidic aqueous solution having a pH of 1 to 6, a part of silicon atoms on the surface of the amorphous silica is removed, and a lot of new on the surface. This is considered to be caused by the formation of a silanol group [vicinal silanol]. This is because the present inventors analyzed SiO 2 material not treated with acid (amorphous silica used in Comparative Example 2) and acid treated SiO 2 of Example 2 by FT-IR. where, as shown in FIG. 1, the none of the spectrum, SiO 2 sharp peaks near 3740cm -1 associated with the silanol groups of the silica surface is seen but subjected to acid treatment, the SiO 2 without acid treatment Since a remarkably large peak is observed in the vicinity of 3680 cm −1 representing vicinal silanol which is not seen, the expression of this vicinal silanol by acid treatment becomes a new active site on the SiO 2 surface and contributes to the improvement of the catalyst performance. It is up to you to consider.
[0018]
【The invention's effect】
As described in detail above, the present invention is an extremely simple operation of simply treating with an acidic aqueous solution of a specific concentration, and the conventional solid catalyst for producing ε-caprolactam by the gas-phase Beckmann rearrangement reaction of cyclohexanone oxime has little catalytic activity. The present inventors have found that amorphous silica, which was considered not to be shown, can be made into an inexpensive and highly active catalyst, and its industrial effect is extremely great.
[0019]
【Example】
The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.
[0020]
Comparative Example 1
A mixture of 5 g of amorphous silica (trade name: D11-10, manufactured by BASF) and 100 g of 1M hydrochloric acid was acid-treated by refluxing the resulting mixture at 100 ° C. for 24 hours, followed by filtration. Silica was obtained. The resulting silica was washed with deionized water and dried at 110 ° C. for 4 hours to obtain a solid catalyst.
[0021]
1.5 g of the solid catalyst thus obtained was charged into a tubular reactor having an inner diameter of 6 mm (height: about 40 mm), and a solution obtained by mixing 9 times by weight ethanol with cyclohexanone oxime as a solvent was added to the pre-evaporator. Vaporized, mixed with a carrier gas, and supplied to the reaction tube for reaction. At this time, the space velocity WHSV of cyclohexanone oxime was 0.33 h −1 , the temperature of the catalyst layer (reaction temperature) was 300 ° C., and the reaction pressure was 10 kPa. The reaction product was collected in a cryogenic trap cooled with liquid nitrogen, then thawed and analyzed by gas chromatography. As a result, the conversion rate was 20.2% and the selectivity was 78.8%.
[0022]
Here, the space velocity WHSV of cyclohexanone oxime was calculated by the following equation, and the conversion rate of cyclohexanone oxime and the selectivity of ε-caprolactam were also calculated by the following equations.
WHSV (hr −1 ) = O / C
Conversion of cyclohexanone oxime (%) = [(XY) / X] × 100
Selectivity of ε-caprolactam (%) = [Z / (XY)] × 100
O, C, X, Y and Z are as follows.
O = Cyclohexanone oxime supply rate (kg / hr)
C = Catalyst weight (kg)
X = number of moles of raw material cyclohexanone oxime supplied Y = number of moles of unreacted cyclohexanone oxime Z = number of moles of ε-caprolactam in the product
Example 2-3, comparative example 3 (old example 1), comparative example 4 (old example 4)
In Comparative Example 1, the same procedure was performed except that the acid concentration during the acid treatment was changed as shown in Table 1. The results are shown in Table 1.
[0024]
[Table 1]
[0025]
Comparative Example 2
In Comparative Example 1, a rearrangement reaction of cyclohexanone oxime was performed in the same manner as in Comparative Example 1 except that the treatment with the aqueous hydrochloric acid solution was not performed. As a result, the conversion rate was 12.8% and the selectivity was 65.4%.
[0026]
Example 5
In Example 2, it carried out like Example 2 except having changed the temperature of acid treatment 100 degreeC into 40 degreeC. As a result, the conversion rate was 35.7% and the selectivity was 70.5%.
[0027]
Comparative example 5 (old example 6)
In Example 2, it carried out like Example 2 except having changed the hydrochloric acid used for acid treatment into sulfuric acid. The results are shown in Table 2.
[0028]
Comparative example 6 (old example 7)
In Example 2, it carried out like Example 2 except having changed hydrochloric acid used for acid treatment into nitric acid. The results are shown in Table 2.
[0029]
[Table 2]
[Brief description of the drawings]
FIG. 1 shows FT-IR spectra of silicon oxide SiO 2 (acid-treated) and untreated silicon oxide SiO 2 (untreated) treated with an acid aqueous solution of the method of the present invention.
Claims (2)
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DE10010189A DE10010189A1 (en) | 1999-03-03 | 2000-03-02 | Production of caprolactam, used in nylon manufacture, comprises gas-phase rearrangement of cyclohexanone oxime on a silica or zeolite catalyst treated or reactivated with acid |
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