この作業は、共同プロジェクトのBOR4STORE（助成契約番号303428）およびインフラストラクチャのプログラムH2FC（助成契約番号FP7-284522）の下で、欧州燃料電池やHydruogen共同事業によってサポートされていました。

1.装置<ol><li>ガス供給、真空システム、センサー（温度、圧力）、および（浴中に浸漬することができます）サンプル環境：高圧ガス配管で接続された4つの主要コンポーネントで構成基本的な超臨界乾燥（SCD）装置を使用してください。建設は、高品質のステンレス鋼製バルブ、継手、および管であることを確認し、80〜300 Kの間の温度範囲内で少なくとも10 MPaのに圧力定格 注：概略図を図1に示されています。 </li><li>窒素SCD（NSCD）の治療のために、ガス供給は0-10 MPaの間の出口圧力制御のための圧力調整器を取り付けた研究純度（&gt; 99.999％）を窒素ガスであることを確認してください。装置に50 Lボトル（20 MPaで）を取り付け、使用する前に、純窒素で複数回、システムをパージします。 </li><li>真空システムは、0.1 Paの&lt;まで真空圧を達成することができるとして装置に接続されていることを確認微制御ニードルバルブ。好ましくは、オイルフリー粗引きポンプと直列に配置された分子ドラッグターボポンプを使用しています。 </li><li> 0.1〜7 Paの間の全測定可能な圧力範囲を達成するために、真空を測定するための低圧力センサと、高圧センサ：SCD処理時の圧力を正確に測定するための少なくとも2つの圧力センサを使用します。 </li><li>サンプルと熱的に接触しているセンサーと77から300 K（ 例えば 、Kタイプの熱電対）の間の正確な測定のために一次ガス投薬マニホールド内のセンサ：典型的なSCDの治療を行うのに必要な最小限の精度のために、少なくとも2つの温度センサを使用して。 </li><li>サンプルホルダーは、治療のために必要な試料の量を格納するための適切な内部容積を有しており、ステンレス鋼で構成されていることを確認してください。 注：バスと熱的に接触している長く円筒状のデザインを補助します。 </li><li>試料容器を閉じフィッティングがapproprであることを確認してください高い圧力と繰り返し使用iate（ 例えば 、Swagelok社VCR）。浴中に試料ホルダーを完全に浸漬するための配管の適切な長さ（浸漬管）を介して外部環境から隔離するためのバルブにサンプル容器の容量を接続します。 </li></ol><img alt="図1" src="/files/ftp_upload/52817/52817fig1.jpg" /> 。浴中の試料の浸漬後、周囲温度および（B）に（A）：図1超臨界窒素乾燥（NSCD）装置の典型的な実験室で使用するための単純化されたNSCD装置の概略図。この研究に記載された方法のためのガス供給は、窒素であるが、この一般的な装置は、CO 2のような温度及び圧力の実用的な範囲内にある臨界点を有する他のSCD流体に一般化です。コンポーネントは目との整合性のために標識されていますプロトコルは、本明細書に記載の電子。 <a href="https://www.jove.com/files/ftp_upload/52817/52817fig1highres.jpg" target="_blank">この図の拡大版を表示するには、こちらをクリックしてください。</a> 2.準備<ol><li>典型的には、アルゴングローブボックスのような不活性雰囲気中で、適当な条件下でロード試料0.2〜0.5グラム（湿式化学合成および標準乾燥方法以下の粉末状のγ-のMg（BH 4）2）試料ホルダーに、周囲温度で以下。フィルターガスケットで試料ホルダー（金具F2）を閉じて、バルブ（弁V4）を閉じます。装置に試料ホルダーを移し、（フィッティングF1）を取り付けます。 </li><li> V2を介して真空と避難する投薬マニホールドを開きます。オープンV3と避難。 V1を介して窒素で装置をパージし、V2を介して避難。オープンV4とシステム（&lt;0.1 ​​Pa）での最小圧力に到達するために、最大24時間、室温でサンプルを避難。 </li><li>サンプル槽を取り付けます（参照<stronG&gt;サンプルホルダーの周りに図2）。シザーリフト、または類似の機構上の位置に浴を上昇させることによって、これを実行します。 </li><li> 110 Kの（T Lを、ステップ3.1を参照してください）希望の未来液体の温度に加熱器を設定し、温度が平衡に達するまで装置を排気し続けます。 </li></ol><img alt="図2" src="/files/ftp_upload/52817/52817fig2.jpg" /> 図2.低温炉サンプルバース。NSCD処理中に試料ホルダーを収容するための適切なcryostatic温泉環境の概略図（左）と写真（右）、77から298 Kの間の試料温度の測定と制御を可能に<a href="https://www.jove.com/files/ftp_upload/52817/52817fig2highres.jpg" target="_blank">してください。この図の拡大版をご覧になるにはこちらをクリックしてください。</a> 3.超臨界窒素暴露<ol&gt; <li> γ-MG（BH 4）2、（このプロトコルでデモの対象）のNSCD処理のためにこれは中程度の液体溶剤の密度に相当する110 Kの液体温度（T L）を選択します（〜0.6グラムミリリットル-1） ;他のNSCD処理プロセスにこのプロトコルの適用のために必要に応じて調整します（下の注を参照）。 </li><li> V2を閉じて真空にシステムをオフに閉じます。圧力が相図の液体領域に増加することができ、ゆっくりと開いV1を絞ります。 2 MPaであり、T Lでシステムを平衡化します。 </li><li> 4時間のために液体N 2でサンプルを浸します。 </li><li>ランプ≤2K分-1で150 Kにヒーターを設定します。 （このP maxは ≥10MPaであるべきである）圧力が装置の最大定格圧力よりも高いが増加しないように許可します。必要に応じて、慎重にV2を介して真空に過剰な圧力を排出。 P maxと150 Kでシステムを平衡化します</li><li> SUPのサンプルを浸し1時間ercritical N 2。 </li></ol><img alt="図3" src="/files/ftp_upload/52817/52817fig3.jpg" /> 図3.窒素の相図。流体密度は、（線形グレースケールに示されている）、窒素、の詳細な相図はREFPROP（状態の変更されたウェッブ·ベネディクト·ルービンの式）を用いて算出される。一定の密度の41様々な線が表示されています紫で。固相境界と沸騰遷移線が赤で示されています。青い線は、N 2を用いて、乾燥や抽出処理に関連する相図の領域の境界を示している。 <a href="https://www.jove.com/files/ftp_upload/52817/52817fig3highres.jpg" target="_blank">この図の拡大版を表示するには、こちらをクリックしてください。</a> 注：他の材料にこのプロトコルのアプリケーションでは、適切なNSCD治療SCHEMを確立対象種の効果的な溶媒和のために必要な条件を選択することによって、電子。 図3に示すN 2の相図を参照してください。液相の高い流体密度を達成するために（ 例えば、0.8〜1がg ml -1の）、中程度の液体密度のために80〜90 KのT Lを選択します（ 例えば、0.6〜0.8グラムミリリットル-1）、90から115 KのT Lの試行錯誤的なアプローチを選択する必要があるかもしれません。 4.超臨界窒素リリース<ol><li>慎重に、V2を絞る圧力はできるだけゆっくり減少することを可能にすることによって、真空にシステムをクラック。繰り返し12〜24時間のおおよその時間スパンで高真空（&lt;0.1 ​​Pa）での緩やかな減少を達成するために、必要に応じて、より高い真空率にシステムをクラック。 </li><li>試料を完全に排気するサンプル槽と全開V2を削除します。 RTおよび高真空（&lt;0.1 ​​Pa）とで平衡化。 </li><li> dと、RTで試料を脱気し、&lt;1〜24時間、0.1 Paのesired。 </li></ol> 5.後処理<ol><li>開閉弁V3とV4、及び装置（フィッティングF1）から試料ホルダーを取り外します。 </li><li>例えば、アルゴンを充填したグローブボックスとして、処理するための不活性環境に試料ホルダーを転送します。以下、周囲温度または、密閉容器内の試料（F2フィッティング）ホルダーとストアからサンプルを削除します。 </li></ol>

<ol>
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P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+N2+Processing+as+a+Route+to+the+Clean+Dehydrogenation+of+Porous+Mg(BH4)2.">Supercritical N2 Processing as a Route to the Clean Dehydrogenation of Porous Mg(BH4)2.</a> J. Am. Chem. Soc. 136 (23), 8181-8184 (2014).</li><li>Borgschulte, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Impurity+Gas+Analysis+of+the+Decomposition+of+Complex+Hydrides.">Impurity Gas Analysis of the Decomposition of Complex Hydrides.</a> J. Phys. Chem. C. 115, 17220-17226 (2011).</li><li>Filinchuk, Y., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Porous+and+Dense+Magnesium+Borohydride+Frameworks:+Synthesis,+Stability,+and+Reversible+Absorption+of+Guest+Species.">Porous and Dense Magnesium Borohydride Frameworks: Synthesis, Stability, and Reversible Absorption of Guest Species.</a> Angew. Chem. Int. Ed. 50, 11162-11166 (2011).</li><li>Li, H. W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Dehydriding+and+rehydriding+processes+of+well-crystallized+Mg(BH4)2+accompanying+with+formation+of+intermediate+compounds.">Dehydriding and rehydriding processes of well-crystallized Mg(BH4)2 accompanying with formation of intermediate compounds.</a> Acta Mater. 56 (6), 1342-1347 (2008).</li><li>Sch&#252;th, F., Bogdanovic, B., Felderhoff, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Light+metal+hydrides+and+complex+hydrides+for+hydrogen+storage.">Light metal hydrides and complex hydrides for hydrogen storage.</a> Chem. Comm. , 2249-2258 (2004).</li><li>Vitillo, J. G., Groppo, E., Bardaj&#237;, E. G., Baricco, M., Bordiga, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fast+carbon+dioxide+recycling+by+reaction+with+&#947;-Mg(BH4)2.">Fast carbon dioxide recycling by reaction with &#947;-Mg(BH4)2.</a> Phys. Chem. Chem. Phys. 16, 22482-22486 (2014).</li><li>Paskevicius, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In-Situ+X-ray+Diffraction+Study+of+&#947;-Mg(BH4)2+Decomposition.">In-Situ X-ray Diffraction Study of &#947;-Mg(BH4)2 Decomposition.</a> J. Phys. Chem. C. 116, 15321-15240 (2012).</li><li>Lemmon, E. W., Huber, M. L., McLinden, M. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=NIST+standard+reference+database+23:+reference+fluid+thermodynamic+and+transport+properties.">NIST standard reference database 23: reference fluid thermodynamic and transport properties.</a> Standard Reference Data Program. , (2008).</li><li>Moquin, P. H. L., Temelli, F. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Kinetic+modeling+of+hydrolysis+of+canola+oil+in+supercritical+media.">Kinetic modeling of hydrolysis of canola oil in supercritical media.</a> J. Supercrit. Fluid. 45, 94-101 (2008).</li><li>Myers, M. N., Giddings, J. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ultra-High-Pressure+Gas+Chromatography+in+Micro+Columns+to+2000+Atmospheres.">Ultra-High-Pressure Gas Chromatography in Micro Columns to 2000 Atmospheres.</a> Sep. Sci. 1 (6), 761-776 (1966).</li><li>McLeary, E. E., Jansen, J. C., Kapteijn, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zeolite+based+films,+membranes+and+membrane+reactors:+Progress+and+prospects.">Zeolite based films, membranes and membrane reactors: Progress and prospects.</a> Microporous Mesoporous Mater. 90, 198-220 (2006).</li><li>Richter, B., Ravnsb&#230;k, D. B., Tumanov, N., Filinchuk, Y., Jensen, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Manganese+borohydride;+synthesis+and+characterization.">Manganese borohydride; synthesis and characterization.</a> Dalton Trans. , (2015).</li><li>Liang, S., Tilotta, D. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extraction+of+petroleum+hydrocarbons+from+soil+using+supercritical+argon.">Extraction of petroleum hydrocarbons from soil using supercritical argon.</a> Anal. Chem. 70 (3), 616-622 (1998).</li></ol>

著者らは、開示することは何もありません。

おそらく、その比較的低い臨界温度（126 K）に、N 2は、歴史的に効果的なSCD溶媒として見過ごされてきました。以前の報告では、3,17,42,43それは、それが（除いて、その相図のこの領域での低流体密度にわずかな溶媒和力を発揮する場合には、周囲温度またはより高い温度の処理のコンテキストでに示唆されています極めて高い圧力43）で。超臨界溶媒としてN 2...

超臨界流体抽出（SFE）と（SCD）の方法がよく、特に食品や石油産業における、だけでなく、化学合成、分析、および材料処理では、実用的なアプリケーションの広い範囲で確立されている乾燥。1-6乾燥の使用またはそれらの臨界点以上の条件で抽出媒体は、多くの場合、より速く、よりクリーンであり、より効率的な従来の（液体）技術よりも、高動作条件の僅かな調整により流体の溶媒和力に対して調整可能であるという追加の利点を有しています。3,7の簡単なSCD方式は、3つの基本的な手順で構成されています。最初のステップは、その高い密度が高い（そしておそらく選択的に対応し、その液体（または近超臨界液体）相に適切に選択されたSCD流体に対象不純物化合物を含む固体（あるいは液体）を出発原料を公開しています標的種に対して7）溶解力。 T彼は第二段階は、加熱流体とその溶解標的種を分離する可能性があり相境界を通過しないように密閉容器内に選択されたSCD流体の臨界点以上のシステムを圧縮されています。最後のステップはゆっくり相境界や道に沿って任意の有害な表面張力の影響に遭遇することなく、再度、脱出する標的種を含む液体溶液を可能にする、臨界温度以上の温度で真空にSCDの流体の圧力を低減します。 出発物質は、対象種が枯渇したままされ、必要に応じて繰り返し処理を施してもよいです。超臨界流体抽出の場合では、標的溶質種の所望の生成物であり、そしてさらなる使用のために溶液から回収される。他の場合には8,9、乾燥又は精製された出発物質は、所望の生成物であり、抽出された不純物を廃棄します。この後者のシナリオは、本明細書で言及しますSCDのアプローチとして、高表面積、例えば真空下での伝統的な熱処理方法は、多くの場合、毛穴をクリアで十分ではなく、有機金属構造体（MOF）、のような微孔性材料の前処理のための有効な戦略であることが発見されましたすべての不要なお客様、または孔の崩壊につながる。10二酸化炭素SCD（CSCD）処理の今のMOFためのルーチン合成後のプロセスであり、11は最大1000パーセント12の未処理の材料上に窒素がアクセス可能な表面積の増加につながるとこのような触媒活性のような他の改善、13その他の注目すべき超臨界流体の応用化学反応のために広く同調可能な媒体としては、14〜16超臨界流体クロマトグラフィー（SCFC）6,17,18とエアロゲルと先進複合材料の合成。19- 22 そののa）に近接：乾燥アプリケーションの場合、SCDの流体は2つの基準に基づいて選択されます標的種に対する条件周囲へ（便宜上およびエネルギーコストやプロセスの複雑さを低減するために）、およびb）その溶媒和力臨界点。二酸化炭素（CO 2）は、それが、非毒性、不燃性、および安価なあるため、多くの用途で便利なSCD液体であることが判明している、その近液に一般的な有機標的種の数に対して高い溶媒和力を発揮するように調整することができます。1-3,7-9他の一般的な超臨界溶媒（または共溶媒）（&lt;10 MPaのと273から323 Kの温度の圧力で）状態は、その周囲と超臨界状態の間の溶媒特性の著しい範囲に及ぶ（水、極性（プロトン性及び非プロトン性の）非極性、および周囲条件に比較的近い臨界点を有するからのスペクトルをカバーする23）、アセトン、エチレン、メタノール、エタノール、エタン、。 二酸化炭素は、これまでで使用される最も一般的なSCD流体です。確立CSCD方法において、反応性出発物質のCO 2は、非常に弱い反応性の臨界点近傍の温度であるため禁止要因ではありません。しかし、加熱下での（おそらく意図的に調整）不安定性に加えて、水またはCO 2の存在下で、彼らの強い反応に、いわゆる複合水素化物（ 例えば 、アラネートと水素化ホウ素）の取り扱いに存在する固有の課題のような物質の特定のクラス。24-26はまた、そこに高密度水素貯蔵化合物などの材料で大きな国際的関心がある27-30したがってまた、ナノ構造および/ ​​または多孔性の品種31-33。このような反応性、不安定な、およびナノ構造材料の効果的な精製の ​​ために、SCD法は、狭いキャビティ内への浸透のための適切な低分子直径を有し、またに対する高い溶媒和力を有する。34 A SCD流体を使用しなければならない有望な戦略でありますターゲットの不純物、WHIルを出発原料自体に向かって非反応残り。ここで、超臨界窒素（N 2）の使用は、抽出及び乾燥の用途のために特に有効な流体が提示されます。特定の超臨界窒素乾燥（NSCD）方法は、標的種はジボランとnブチル化合物（と似ているが、n個のブタン、具体的に識別できない）の両方を含むγ相マグネシウム、水素化ホウ素の精製の ​​ために説明します。以下のプロトコルは、簡単に他の超臨界窒素乾燥又は抽出プロセスに一般的な拡張のために変更することができます。

<table><tbody><tr><td>Compressed Nitrogen Gas</td><td>Messer Schweiz AG</td><td></td><td>50 L bottle, purity &gt; 99.999%, &amp;lt;3 ppmv H&lt;sub&gt;2&lt;/sub&gt;O</td></tr><tr><td>Liquid Nitrogen</td><td>Pan Gas AG</td><td></td><td>Bulk storage, on site</td></tr><tr><td>Custom Supercritical Drying Apparatus</td><td>Empa</td><td></td><td>Swagelok (compression fitting and VCR) components</td></tr><tr><td>Custom Cryogenic Furnace Bath</td><td>Empa</td><td></td><td></td></tr><tr><td>Custom Labview Interface</td><td>Empa</td><td></td><td></td></tr></tbody></table>

supercritical nitrogen processing for the purification of reactive porous materials

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. Herein, nitrogen is presented as a novel supercritical drying fluid for specialized applications such as in the processing of reactive porous materials, where carbon dioxide and other fluids are not appropriate due to their higher chemical reactivity. Nitrogen exhibits similar physical properties in the near-critical region of its phase diagram as compared to carbon dioxide: a widely tunable density up to ~1 g ml-1, modest critical pressure (3.4 MPa), and small molecular diameter of ~3.6 &#197;. The key to achieving a high solvation power of nitrogen is to apply a processing temperature in the range of 80-150 K, where the density of nitrogen is an order of magnitude higher than at similar pressures near ambient temperature. The detailed solvation properties of nitrogen, and especially its selectivity, across a wide range of common target species of extraction still require further investigation. Herein we describe a protocol for the supercritical nitrogen processing of porous magnesium borohydride.

アルカリおよびアルカリ土類金属のホウ水素化物が分解して水素ガスの大きいコンテンツを配信する可能性のある水素貯蔵材料である。例えば、ジボランなど27,29の他の分解生成物はまた、時々脱着ガス中に検出されているが、その起源は先験的に明らかではありません;それは純粋な相分解の産物であることが可能であるが、また、化学合成からの残りの不純物の反応不純物または?...

Watch this Scientific Journal Video about Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials at JoVE.com

Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

窒素は、その分子サイズが小さい、近超臨界液体領域で高密度、および化学的不活性に抽出または乾燥工程のための効果的な超臨界流体です。我々は、反応性、多孔性材料の精製処理のための超臨界窒素乾燥プロトコルを提示します。

反応性多孔質材料を精製するための超臨界窒素処理

Supercritical fluid extraction and drying methods are well established in numerous applications for the synthesis and processing of porous materials. ...

supercritical-nitrogen-processing-for-purification-reactive-porous

Research

JoVE Journal

Chemistry

14.7K ビュー.  Empa, Swiss Federal Laboratories for Materials Science and Technology. 窒素は、その分子サイズが小さい、近超臨界液体領域で高密度、および化学的不活性に抽出または乾燥工程のための効果的な超臨界流体です。我々は、反応性、多孔性材料の精製処理のための超臨界窒素乾燥プロトコルを提示します。 

ビデオ: Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

Synthesis and Functionalization of Nitrogen-doped Carbon Nanotube Cups with Gold Nanoparticles as Cork Stoppers

Nitrogen-doped carbon nanotubes consist of many cup-shaped graphitic compartments termed as nitrogen-doped carbon nanotube cups (NCNCs). These as-synthesized graphitic nanocups from chemical vapor deposition (CVD) method were stacked in a head-to-tail fashion held only through noncovalent interactions. Individual NCNCs can be isolated out of their stacking structure through a series of chemical and physical separation processes. First, as-synthesized NCNCs were oxidized in a mixture of strong acids to introduce oxygen-containing defects on the graphitic walls. The oxidized NCNCs were then processed using high-intensity probe-tip sonication which effectively separated the stacked NCNCs into individual graphitic nanocups. Owing to their abundant oxygen and nitrogen surface functionalities, the resulted individual NCNCs are highly hydrophilic and can be effectively functionalized with gold nanoparticles (GNPs), which preferentially fit in the opening of the cups as cork stoppers. These graphitic nanocups corked with GNPs may find promising applications as nanoscale containers and drug carriers.

We discussed the synthesis of individual graphitic nanocups using a series of techniques including chemical vapor deposition, acid oxidation and probe-tip sonication. By citrate reduction of HAuCl4, the graphitic nanocups were effectively corked with gold nanoparticles due to the chemically reactive edges of the cups.

コルク栓のように金ナノ粒子と窒素ドープカーボンナノチューブカップの合成と機能化

Nitrogen-doped carbon  nanotubes consist of many cup-shaped graphitic compartments termed as  nitrogen-doped carbon nanotube cups (NCNCs).  These ...

工学

Preparing Silica Aerogel Monoliths via a Rapid Supercritical Extraction Method

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The procedure requires 15-20 min of preparation time, during which a liquid precursor mixture is prepared and poured into wells of a metal mold that is placed between the platens of a hydraulic hot press, followed by several hours of processing within the hot press. The precursor solution consists of a 1.0:12.0:3.6:3.5 x 10-3 molar ratio of tetramethylorthosilicate (TMOS):methanol:water:ammonia. In each well of the mold, a porous silica sol-gel matrix forms. As the temperature of the mold and its contents is increased, the pressure within the mold rises. After the temperature/pressure conditions surpass the supercritical point for the solvent within the pores of the matrix (in this case, a methanol/water mixture), the supercritical fluid is released, and monolithic aerogel remains within the wells of the mold. With the mold used in this procedure, cylindrical monoliths of 2.2 cm diameter and 1.9 cm height are produced. Aerogels formed by this rapid method have comparable properties (low bulk and skeletal density, high surface area, mesoporous morphology) to those prepared by other methods that involve either additional reaction steps or solvent extractions (lengthier processes that generate more chemical waste).The rapid supercritical extraction method can also be applied to the fabrication of aerogels based on other precursor recipes.

This article describes a rapid supercritical extraction method for fabricating silica aerogels. By utilizing a confined mold and hydraulic hot press, monolithic aerogels can be made in eight hours or less.

急速な超臨界抽出方法によるシリカエアロゲルモノリスを準備

A procedure for the fabrication of monolithic silica aerogels in eight hours or less via a rapid supercritical extraction process is described. The ...

化学

Preparation of Highly Porous Coordination Polymer Coatings on Macroporous Polymer Monoliths for Enhanced Enrichment of Phosphopeptides

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous polymer monoliths. The developed approach is based on the preparation of a macroporous polymer containing carboxylic acid functional groups and the subsequent step-by-step solution-based controlled growth of a layer of a porous coordination polymer on the surface of the pores of the polymer monolith. The prepared metal-organic polymer hybrid has a high specific micropore surface area. The amount of iron(III) sites is enhanced through metal-organic coordination on the surface of the pores of the functional polymer support. The increase of metal sites is related to the number of iterations of the coating process.
The developed preparation scheme is easily adapted to a capillary column format. The functional porous polymer is prepared as a self-contained single-block porous monolith within the capillary, yielding a flow-through separation device with excellent flow permeability and modest back-pressure. The metal-organic polymer hybrid column showed excellent performance for the enrichment of phosphopeptides from digested proteins and their subsequent detection using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The presented experimental protocol is highly versatile, and can be easily implemented to different organic polymer supports and coatings with a plethora of porous coordination polymers and metal-organic frameworks for multiple purification and/or separation applications.

A procedure for the preparation of porous hybrid separation media composed of a macroporous polymer monolith internally coated by a high surface area microporous coordination polymer is presented.

リン酸化ペプチドの強化充実のためのマクロポーラスポリマーモノリスの高度に多孔性配位高分子コーティングの製造

We describe a protocol for the preparation of hybrid materials based on highly porous coordination polymer coatings on the internal surface of macroporous ...

Procedures of Laboratory Fumigation for Pest Control with Nitric Oxide Gas

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on fresh products and procedures for residue analysis and product quality evaluation. An airtight fumigation chamber containing fresh fruit and vegetables is first flushed with nitrogen (N2) to establish an ultralow oxygen (ULO) environment followed by injection of NO. The fumigation chamber is then kept at a low temperature of 2 - 5 &#176;C for a specified time period necessary to kill a target pest to complete a fumigation treatment. At the end of a fumigation treatment, the fumigation chamber is flushed with N2 to dilute NO prior to opening the chamber to ambient air to prevent the reaction between NO and O2, which produces NO2 and may damage delicate fresh products. At different times after NO fumigation, NO2 in headspace and nitrate and nitrite in liquid samples were measured as residues. Product quality was evaluated after 2 weeks of post-treatment cold storage to determine effects of NO fumigation on product quality. Keeping&#160;O2 from reacting with NO is critical to NO fumigation and is an important part of the protocols. Measuring NO levels is challenging and a practical solution is provided. Possible protocol modifications are also suggested for measuring NO levels in the fumigation chambers as well as residues. NO fumigation has the potential to be a practical alternative to methyl bromide fumigation for postharvest pest control on fresh and stored products. This publication is intended to assist other researchers in conducting NO fumigation research for postharvest pest control and accelerating the development of NO fumigation for practical applications.

This paper describes nitric oxide (NO) fumigation protocols for postharvest pest control. Fumigation chambers are flushed with nitrogen (N2) to establish ultralow oxygen conditions before NO is injected. At the end, chambers are flushed with N2 to dilute NO before exposing products to ambient air to prevent exposure to NO2.

窒素酸化物ガスで害虫駆除のため研究所くん蒸処理の手順

Nitric oxide (NO) is a newly discovered fumigant for postharvest pest control. This paper provides detailed protocols for conducting NO fumigation on ...

環境学

On-line Analysis of Nitrogen Containing Compounds in Complex Hydrocarbon Matrixes

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The composition of heavy crude oils and shale oils varies substantially depending on the origin of the mixture. In particular they contain an increased amount of nitrogen containing compounds compared to the conventionally used sweet crude oils. As nitrogen compounds have an influence on the operation of thermal processes occurring in coker units and steam crackers, and as some species are considered as environmentally hazardous, a detailed analysis of the reactions involving nitrogen containing compounds under pyrolysis conditions provides valuable information. Therefore a novel method has been developed and validated with a feedstock containing a high nitrogen content, i.e., a shale oil. First, the feed was characterized offline by comprehensive two-dimensional gas chromatography (GC &#215; GC) coupled with a nitrogen chemiluminescence detector (NCD). In a second step the on-line analysis method was developed and tested on a steam cracking pilot plant by feeding pyridine dissolved in heptane. The former being a representative compound for one of the most abundant classes of compounds present in shale oil. The composition of the reactor effluent was determined via an in-house developed automated sampling system followed by immediate injection of the sample on a GC &#215; GC coupled with a time-of-flight mass spectrometer (TOF-MS), flame ionization detector (FID) and NCD. A novel method for quantitative analysis of nitrogen containing compounds using NCD and 2-chloropyridine as an internal standard has been developed and demonstrated.

A method combining comprehensive two-dimensional gas chromatography with nitrogen chemiluminescence detection has been developed and applied to on-line analysis of nitrogen containing compounds in a complex hydrocarbon matrix.

オンライン複雑な炭化水素マトリックス中の窒素含有化合物の分析

The shift to heavy crude oils and the use of alternative fossil resources such as shale oil are a challenge for the petrochemical industry. The ...

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for Cu(II) Through Microwave Pre-Pyrolysis

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is proposed. Bagasse impregnated with phosphoric acid is utilized as the precursor. To pyrolyze the precursor, two separate heating modes are used: microwave pyrolysis and conventional electric-heating pyrolysis. The resulting bagasse-derived carbon samples are modified with nitrification and reduction modification. Nitrogen (N)/oxygen (O) functional groups are simultaneously introduced to the surface of activated carbon, enhancing its adsorption of Cu(II) by complexing and ion-exchange. Characterization and copper adsorption experiments are performed to investigate the physicochemical properties of four prepared carbon samples and determine which heating method favors the subsequent modification for doping of N/O functional groups. In this technique, based on analyzing data of nitrogen adsorption, Fourier transform infrared spectroscopy, and batch adsorption experiments, it is proven that microwave-pyrolyzed carbon has more defect sites and, therefore, time-saving effective microwave pyrolysis contributes more N/O species to the carbon, although it leads to a lower specific surface area. This technique offers a promising route to synthesis adsorbents with higher nitrogen and oxygen content and a higher adsorption capacity of heavy-metal ions in wastewater remediation applications.

Preparation of Biomass-based Mesoporous Carbon with Higher Nitrogen-/Oxygen-chelating Adsorption for CuII Through Microwave Pre-Pyrolysis

Here, we present a protocol to synthesize nitrogen/oxygen dual-doped mesoporous carbon from biomass by chemical activation in different pyrolysis modes followed by modification. We demonstrate that the microwave pyrolysis benefits the subsequent modification process to simultaneously introduce more nitrogen and oxygen functional groups on the carbon.

高い窒素-メソ孔炭素のバイオマス ベースの準備/電子レンジ前熱分解による銅 (ii) 酸素キレート吸着

An environment-friendly technique for synthesizing biomass-based mesoporous activated carbon with high nitrogen-/oxygen-chelating adsorption for Cu(II) is ...

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has been increasing because global nitrogen loads have dramatically increased following industrialization. Dissimilatory nitrate reduction to ammonium (DNRA) and denitrification are both microbial processes that use NO3&#8722; for respiration. Compared to denitrification, quantitative determinations of the DNRA activity have been carried out only to a limited extent. This has led to an insufficient understanding of the importance of DNRA in NO3&#8722; transformations and the regulating factors of this process. The objective of this paper is to provide a detailed procedure for the measurement of the potential DNRA rate in environmental samples. In brief, the potential DNRA rate can be calculated from the 15N-labeled ammonium (15NH4+) accumulation rate in 15NO3&#8722; added incubation. The determination of the 14NH4+ and 15NH4+ concentrations described in this paper is comprised of the following steps. First, the NH4+ in the sample is extracted and trapped on an acidified glass filter as ammonium salt. Second, the trapped ammonium is eluted and oxidized to NO3&#8722; via persulfate oxidation. Third, the NO3&#8722; is converted to N2O via an N2O reductase deficient denitrifier. Finally, the converted N2O is analyzed using a previously developed quadrupole gas chromatography&#8211;mass spectrometry system. We applied this method to salt marsh sediments and calculated their potential DNRA rates, demonstrating that the proposed procedures allow a simple and more rapid determination compared to previously described methods.

Measurement of the Potential Rates of Dissimilatory Nitrate Reduction to Ammonium Based on 14NH4+/15NH4+ Analyses via Sequential Conversion to N2O

A series of methods to determine the potential DNRA rate based on 14NH4+/15NH4+ analyses is provided in detail. NH4+ is converted into N2O via several steps and analyzed using quadrupole gas chromatography&#8211;mass spectrometry.

N2Oへの逐次変換による14NH4+/154+ 1415NH4++分析に基づくアンモニウムへの非シミラトリー硝酸還元の電位率の測定

The importance of understanding the fate of nitrate (NO3&#8722;), which is the dominant N species transferred from terrestrial to aquatic ecosystems, has ...

Surface Properties of Synthesized Nanoporous Carbon and Silica Matrices

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) with a 4.6 nm pore size, and ordered silica porous matrix, SBA-15, with a 5.3 nm pore size. This work describes the surface properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the differently ordered porous materials with similar pore sizes. For this purpose, OMC and SBA-15 with highly ordered nanoporous structures are synthesized via impregnation of the silica matrix by applying a carbon precursor and by the sol-gel method, respectively. The porous structure of investigated systems is characterized by an N2 adsorption-desorption analysis at 77 K. To determine the electrochemical character of the surface of synthesized materials, potentiometric titration measurements are conducted; the obtained results for OMC shows a significant pHpzc shift toward the higher values of pH, relative to SBA-15. This suggests that investigated OMC has surface properties related to oxygen-based functional groups. To describe the surface properties of the materials, the contact angles of liquids penetrating the studied porous beds are also determined. The capillary rise method has confirmed the increased wettability of the silica walls relative to the carbon walls and an influence of the pore roughness on the fluid/wall interactions, which is much more pronounced for silica than for carbon mesopores. We have also studied the melting behavior of D2O confined in OMC and SBA-15 by applying the dielectric method. The results show that the depression of the melting temperature of D2O in the pores of OMC is about 15 K higher relative to the depression of the melting temperature in SBA-15 pores with a comparable 5 nm size. This is caused by the influence of adsorbate/adsorbent interactions of the studied matrices.

Here we report the synthesis and characterization of ordered nanoporous carbon (with a 4.6 nm pore size) and SBA-15 (with a 5.3 nm pore size). The work describes the surface and textural properties of nanoporous molecular sieves, their wettability, and the melting behavior of D2O confined in the materials.

合成多孔性カーボンとシリカ マトリックスの表面特性

In this work, we report the synthesis and characterization of ordered nanoporous carbon material (also called ordered mesoporous carbon material [OMC]) ...

Ammonia Synthesis at Low Pressure

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in areas requiring ammonia for synthetic fertilizer. Such wind energy is often called &#34;stranded,&#34; because it is only available far from population centers where it can be directly used.
In the proposed low pressure process, nitrogen is made from air using pressure swing absorption, and hydrogen is produced by electrolysis of water. While these gases can react at approximately 400 &#176;C in the presence of a promoted conventional catalyst, the conversion is often limited by the reverse reaction, which makes this reaction only feasible at high pressures. This limitation can be removed by absorption on an ammine-like calcium or magnesium chloride. Such alkaline metal halides can effectively remove ammonia, thus suppressing the equilibrium constraints of the reaction. In the proposed absorption-enhanced ammonia synthesis process, the rate of reaction may then be controlled not by the chemical kinetics nor the absorption rates, but by the rate of the recycle of unreacted gases. The results compare favorably with ammonia made from a conventional small scale Haber-Bosch process.

Ammonia can be synthesized at low pressure by using a conventional catalyst and an ammonia selective absorbent.

低圧でのアンモニア合成

Ammonia can be synthesized at low pressure by the use of an ammonia selective absorbent. The process can be driven with wind energy, available locally in ...

生物工学

<meta charset="utf8"></head><body>ペプチド合成のための汎用性の高い自家製マイクロ波支援システム

An Inexpensive Adaptation of a Commercial Microwave Reactor for Solid Phase Peptide Synthesis

A home-built apparatus to perform solid phase peptide synthesis (SPPS), assisted by microwave irradiation and heating, is presented. In contrast to conventional SPPS reaction vessels, which drain solvent and byproducts via a frit located at the bottom of the vessel, the presented apparatus employs a gas dispersion tube under vacuum to remove solvent, byproducts, and excess reagents. The same gas dispersion tube supplies nitrogen gas agitation of the SPPS beads during the reaction steps of coupling and deprotection. Microwave heating is beneficial for SPPS couplings of sterically hindered residues, such as alpha-aminoisobutyric acid (Aib), an alpha,alpha-dialkylated amino acid residue. This home-built apparatus has been used to prepare, via manual Fmoc SPPS methods, heptameric and octameric peptides dominated by the Aib residue, which is notoriously difficult to couple under standard room temperature conditions and reagents. Further, typical commercial microwave SPPS reactors are dedicated exclusively to SPPS synthesis rendering them inaccessible to non-SPPS users. In contrast, the presented apparatus preserves the versatility of the microwave reactor for conventional microwave acceleration of chemical reactions, as the apparatus is trivially removed from the commercial microwave reactor.

<meta charset="utf8"></head><body>固相ペプチド合成のための商用マイクロ波反応器の安価な適応

A simple, inexpensive, and novel apparatus for performing solid phase peptide syntheses in a commercial microwave reactor is presented.

固相ペプチド合成のための商用マイクロ波反応器の安価な適応

A home-built apparatus to perform solid phase peptide synthesis (SPPS), assisted by microwave irradiation and heating, is presented. In contrast to ...

反応性多孔質材料を精製するための超臨界窒素処理

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