这项工作是由欧洲燃料电池和Hydruogen联合执行下的合作项目BOR4STORE（批准号:303428协定）和基础设施项目H2FC（赠款协​​议号FP7-284522）的支持。

1.仪器<ol><li>使用由通过高压气体配管连接的四个主要部件的基本超临界干燥（SCD）装置:气体供应，真空系统，传感器（温度和压力），和样品环境（其可在浴中浸没）。确保建设优质不锈钢阀门，管件和管道，额定压力为至少10兆帕80-300 K之间的温度范围内 注意:示意图示于图1。 </li><li>对于氮理学博士（NSCD）处理，确保气源的纯度研究装有0-10兆帕之间的出口压力控制压力调节器（&gt; 99.999％）的氮气。附加一个50升瓶（20兆帕）的装置，并在使用前冲洗系统用纯氮气多次。 </li><li>保证真空系统能够实现真空压力下降到&lt;0.1帕的并且被连接到该装置与一精细控制针阀。优选地，使用无油粗抽泵和一个分子拖动涡轮泵，串联放置。 </li><li>使用至少两个压力传感器对压力的精确测量期间理学治疗:真空测量和高压力传感器的低压压力传感器来实现0.1-10 7帕之间的总测的压力范 ​​围。 </li><li>使用至少两个温度传感器，用于必要的最小的精度来执行典型理学治疗:与样品和77-300 K的主要气体计量歧管用于精确测量内的传感器热接触的传感器（ 例如 ，K型热电偶） 。 </li><li>检查该样本保持器必须包含必要的样品用于治疗的量的适当的内部容积，并且由不锈钢制成。 注:加长的圆柱形设计有助于同浴热接触。 </li><li>确保封闭该样本容器的嵌合是appropr黄昏时分的高压和重复使用（ 例如 ，世伟洛克VCR）。通过管道的适当长度（汲取管），用于样品支架的完全浸没入熔池连接样本容器容积的阀从外部环境隔离。 </li></ol><img alt="图1" src="/files/ftp_upload/52817/52817fig1.jpg" /> 在环境温度和（B）（A）中，在浴中的试样浸入后: 图1.超临界氮气干燥（NSCD）一种用于在典型的实验室使用简化NSCD装置的示意图。气体供应在这项工作中所描述的方法是氮，但是这一般装置推广到其他理学流体与一个临界点躺着的温度和压力，如CO 2的实用范围内。组件被标记为与第一致Ë这里所描述的协议。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/52817/52817fig1highres.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 2.准备工作<ol><li>负载0.2-0.5克样品（γ-Mg系（BH 4）2，粉末形式，以下湿式化学合成和标准的干燥方法）到样本保持在适当条件下，通常在惰性气氛如氩气手套箱，在环境温度下或更低。关闭样品保持器（嵌合F2）与过滤器垫圈，然后关闭阀（阀V4）。样品架传送到装置和连接（嵌合F1）。 </li><li>打开计量歧管通过V2真空和撤离。打开V3和疏散。由V1用氮气净化的装置和经由V2撤离。开放V4和撤离样品在RT达24小时，以达到系统（&lt;0.1帕）的最小压力。 </li><li>安装示例浴（见<strong&gt;的图2）的样品架周围。通过提高浴到位上剪叉式升降机，或类似的机制执行此。 </li><li>设定加热到所需未来液体温度（T L，见步骤3.1）的110 K，并继续撤离设备直至温度达到平衡。 </li></ol><img alt="图2" src="/files/ftp_upload/52817/52817fig2.jpg" /> 图2.低温炉样品浴一个示意图（左）和一个cryostatic热浴环境照片（右）相应于含有NSCD处理期间的样品架，允许测量和77-298 K之间的样品温度控制<a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/52817/52817fig2highres.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 3.超临界氮曝光<ol&gt; <li>对于γ-Mg系（BH 4）2，（示范的在这个协议中的主题）的NSCD处理选择的110 K的液体温度（T L）这对应于一个中等的液体溶剂密度（〜0.6克毫升-1） ;在必要时获得本协议的其他NSCD治疗过程中的应用调整（见下面的注释）。 </li><li>通过关闭V2封闭该系统至真空。油门开V1慢，使压力提高到相图的液相区。平衡系统在2兆帕和T L。 </li><li>浸泡试样在液体N 2 4小时。 </li><li>与斜坡≤2，K MIN -1设置加热器150开。允许的压力增加不高于该装置的最大额定压力（此{P MAX应≥10兆帕）;如果必要的话，仔细地发泄过剩的压力，通过V2真空。平衡系统以P max和150 K. </li><li>泡在SUP样本ercritical N 2 1小时。 </li></ol><img alt="图3" src="/files/ftp_upload/52817/52817fig3.jpg" /> 图3.氮相图氮，这里的流体密度（如图线性灰度）详细的相图使用REFPROP（状态的修正韦伯-笃-鲁宾公式）计算。41多种线密度不变的示紫色。固相边界和沸腾过渡线被显示为红色。蓝线表示的相图是有关使用N 2干燥或提取加工的区域的边界。 <a href="https://jove.unicartagenaproxy.elogim.com/files/ftp_upload/52817/52817fig3highres.jpg" target="_blank">请点击此处查看该图的放大版本。</a> 注意:对于此协议的其他材料的应用，建立适当的治疗NSCD舍姆Ë通过选择所需的目标物种的有效溶解的条件。指的是N 2的相图，在图3中所示，为了实现高的流体密度在液相（ 例如，0.8-1克·毫升-1），选择80-90 K.一件T l对于中等的液体密度（ 例如，0.6-0.8克·毫升-1），选择90-115 K的试错法一个T L可能是必要的。 4.超临界氮素释放<ol><li>仔细节流V2，使压力尽可能慢减少破解系统至真空。反复破解系统根据需要实现12-24小时的大致时间跨度逐渐下降到高真空（&lt;0.1 ​​Pa）的高真空率。 </li><li>取下样品浴缸和全开V2完全撤离样品。平衡在室温和高真空（&lt;0.1帕）。 </li><li>脱气样品在RT和&lt;0.1帕为1-24小时，为desired。 </li></ol> 5.后处理<ol><li>关闭阀门V3和V4，和从（嵌合F1），该装置移动样品支架。 </li><li>样品架传送到惰性环境进行处理，如在氩气填充的手套箱中。在密封容器中在环境温度下或低于除去从样品保持器（嵌合F2），并存储该样本。 </li></ol>

<ol>
	<li>McHugh, M. A., Krukonis, V. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Supercritical Fluid Extraction. , (1986).</li><li>Schneider, G. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Physicochemical+Principles+of+Extraction+with+Supercritical+Gases.">Physicochemical Principles of Extraction with Supercritical Gases.</a> Angew. Chem. lnt. Ed. 17, 716-727 (1978).</li><li>Williams, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Extraction+with+Supercritical+Gases.">Extraction with Supercritical Gases.</a> Chem. Eng. Sci. 36 (11), 1769-1788 (1981).</li><li>Eckert, C. A., Knutson, B. I., Debenedetti, P. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+fluids+as+solvents+for+chemical+and+materials+processing.">Supercritical fluids as solvents for chemical and materials processing.</a> Nature. 383, 313-318 (1996).</li><li>Cooper, A. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Polymer+synthesis+and+processing+using+supercritical+carbon+dioxide.">Polymer synthesis and processing using supercritical carbon dioxide.</a> J. Mater. Chem. 10, 207-234 (2000).</li><li>Klesper, E., Corwin, A. H., Turner, D. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+pressure+gas+chromatography+above+critical+temperatures.">High pressure gas chromatography above critical temperatures.</a> J. Org. Chem. 27, 700-701 (1962).</li><li>Tucker, S. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solvent+Density+Inhomogeneities+in+Supercritical+Fluids.">Solvent Density Inhomogeneities in Supercritical Fluids.</a> Chem. Rev. 99 (2), 391-418 (1999).</li><li>Hubert, P., Vitzthum, O. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fluid+Extraction+of+Hops,+Spices,+and+Tobacco+with+Supercritical+Gases.">Fluid Extraction of Hops, Spices, and Tobacco with Supercritical Gases.</a> Angew. Chem. Int. Ed. 17 (10), 710-715 (1978).</li><li>Zosel, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Separation+with+Supercritical+Gases:+Practical+Applications.">Separation with Supercritical Gases: Practical Applications.</a> Angew. Chem. Int. Ed. 17 (10), 702-709 (1978).</li><li>Nelson, A. P., Farha, O. K., Mulfort, K. L., Hupp, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+Processing+as+a+Route+to+High+Internal+Surface+Areas+and+Permanent+Microporosity+in+Metal&#8722;Organic+Framework+Materials.">Supercritical Processing as a Route to High Internal Surface Areas and Permanent Microporosity in Metal&#8722;Organic Framework Materials.</a> J. Am. Chem. Soc. 131, 458-460 (2009).</li><li>Liu, B., Wong-Foy, A. G., Matzger, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Rapid+and+enhanced+activation+of+microporous+coordination+polymers+by+flowing+supercritical+CO2.">Rapid and enhanced activation of microporous coordination polymers by flowing supercritical CO2.</a> Chem. Commun. 49, 1419-1421 (2013).</li><li>Cooper, A. I., Rosseinsky, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Metal&#8211;organic+frameworks:+improving+pore+performance.">Metal&#8211;organic frameworks: improving pore performance.</a> Nat. Chem. 1, 26-27 (2009).</li><li>Totten, R. K., 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=Enhanced+Catalytic+Activity+through+the+Tuning+of+Micropore+Environment+and+Supercritical+CO2+Processing:+Al(Porphyrin)-Based+Porous+Organic+Polymers+for+the+Degradation+of+a+Nerve+Agent+Simulant.">Enhanced Catalytic Activity through the Tuning of Micropore Environment and Supercritical CO2 Processing: Al(Porphyrin)-Based Porous Organic Polymers for the Degradation of a Nerve Agent Simulant.</a> J. Am. Chem. Soc. 135, 11720-11723 (2013).</li><li>Savage, P. E., Gopalan, S., Mizan, T. I., Martino, C. J., Brock, E. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reactions+at+supercritical+conditions:+Applications+and+fundamentals.">Reactions at supercritical conditions: Applications and fundamentals.</a> AIChE J. 41 (7), 1723-1778 (1995).</li><li>Baiker, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+Fluids+in+Heterogeneous+Catalysis.">Supercritical Fluids in Heterogeneous Catalysis.</a> Chem. Rev. 99 (2), 453-474 (1999).</li><li>Jessop, P. G., Ikariya, T., Noyori, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Homogeneous+Catalysis+in+Supercritical+Fluids.">Homogeneous Catalysis in Supercritical Fluids.</a> Chem. Rev. 99 (2), 475-494 (1999).</li><li>Giddings, J. C., Myers, M. N., McLaren, L., Keller, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=High+Pressure+Gas+Chromatography+Of+Nonvolatile+Species.">High Pressure Gas Chromatography Of Nonvolatile Species.</a> Science. 162 (3849), 67-73 (1968).</li><li>Gere, D. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+Fluid+Chromatography.">Supercritical Fluid Chromatography.</a> Science. 222, 253-259 (1983).</li><li>Kistler, S. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coherent+Expanded+Aerogels+and+Jellies.">Coherent Expanded Aerogels and Jellies.</a> Nature. 127, 741-741 (1931).</li><li>Biener, J., 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=Advanced+carbon+aerogels+for+energy+applications.">Advanced carbon aerogels for energy applications.</a> Energy Environ. Sci. 4, 656-667 (2011).</li><li>Mor&#232;re, J., 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=Deposition+of+Pd+into+mesoporous+silica+SBA-15+using+supercritical+carbon+dioxide.">Deposition of Pd into mesoporous silica SBA-15 using supercritical carbon dioxide.</a> J. Supercrit. Fluids. 56 (2), 213-222 (2011).</li><li>Sathish, M., Mitani, S., Tomai, T., Honma, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Supercritical+fluid+assisted+synthesis+of+N-doped+graphene+nanosheets+and+their+capacitance+behavior+in+ionic+liquid+and+aqueous+electrolytes.">Supercritical fluid assisted synthesis of N-doped graphene nanosheets and their capacitance behavior in ionic liquid and aqueous electrolytes.</a> J. Mater. Chem. A. 2, 4731-4738 (2014).</li><li>Toews, K. L., Shroll, R. M., Wai, C. M., Smart, N. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=pH-Defining+Equilibrium+between+Water+and+Supercritical+CO2.+Influence+on+SFE+of+Organics+and+Metal+Chelates.">pH-Defining Equilibrium between Water and Supercritical CO2. Influence on SFE of Organics and Metal Chelates.</a> Anal. Chem. 67 (22), 4040-4043 (1995).</li><li>Barbaras, G., Barbaras, G. D., Finholt, A. E., Schlesinger, H. I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cause+Of+Explosions+Occasionally+Observed+During+Evaporation+Of+Solutions+Of+Aluminum+Hydride+And+Related+Compounds.">Cause Of Explosions Occasionally Observed During Evaporation Of Solutions Of Aluminum Hydride And Related Compounds.</a> J. Am. Chem. Soc. 70, 877 (1948).</li><li>Burr, J. G., Brown, W. G., Heller, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Reduction+of+Carbon+Dioxide+to+Formic+Acid.">The Reduction of Carbon Dioxide to Formic Acid.</a> J. Am. Chem. Soc. 72 (6), 2560-2562 (1950).</li><li>Hugelshofer, C. L., 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=Gas&#8722;Solid+Reaction+of+Carbon+Dioxide+with+Alanates.">Gas&#8722;Solid Reaction of Carbon Dioxide with Alanates.</a> J. Phys. Chem. C. 118, 15940-15945 (2014).</li><li>Orimo, S. I., Nakamori, Y., Eliseo, J. R., Z&#252;ttel, A., Jensen, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Complex+Hydrides+for+Hydrogen+Storage.">Complex Hydrides for Hydrogen Storage.</a> Chem. Rev. 107 (10), 4111-4132 (2007).</li><li>Gross, K. J., Thomas, G. J., Jensen, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Catalyzed+alanates+for+hydrogen+storage.">Catalyzed alanates for hydrogen storage.</a> J. Alloys Compd. 330-332, 683-690 (2002).</li><li>Li, H. W., Yan, Y., Orimo, S. I., Z&#252;ttel, A., Jensen, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Recent+Progress+in+Metal+Borohydrides+for+Hydrogen+Storage.">Recent Progress in Metal Borohydrides for Hydrogen Storage.</a> Energies. 4 (1), 185-214 (2011).</li><li>Frankcombe, T. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Proposed+Mechanisms+for+the+Catalytic+Activity+of+Ti+in+NaAlH4.">Proposed Mechanisms for the Catalytic Activity of Ti in NaAlH4.</a> Chem. Rev. 112, 2164 (2012).</li><li>Vajo, J. J., Olson, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrogen+storage+in+destabilized+chemical+systems.">Hydrogen storage in destabilized chemical systems.</a> Scr. Mater. 56, 829 (2007).</li><li>Zhang, 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=LiBH4+nanoparticles+supported+by+disordered+mesoporous+carbon:+Hydrogen+storage+performances+and+destabilization+mechanisms.">LiBH4 nanoparticles supported by disordered mesoporous carbon: Hydrogen storage performances and destabilization mechanisms.</a> Int. J. Hyd. Energ. 32 (16), 3976-3980 (2007).</li><li>Christian, M. L., Aguey-Zinsou, K. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Core&#8211;Shell+Strategy+Leading+to+High+Reversible+Hydrogen+Storage+Capacity+for+NaBH4.">Core&#8211;Shell Strategy Leading to High Reversible Hydrogen Storage Capacity for NaBH4.</a> ACS Nano. 6 (9), 7739-7751 (2012).</li><li>Stadie, N. 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>

作者什么都没有透露。

这可能是由于其相对较低的临界温度（126 K），N 2 -历来被忽视作为有效理学溶剂。在早先的报告，3,17,42,43它仅被暗示在等于或高于室温，在那里它显示只有少量的溶剂化功率加工温度的范围内，由于其低的流体密度在其相图的这个区域（除在极高的压力，43）。在实现的N 2的实际效用作为超临界溶剂的关键步骤是在维持处理温度在临界点附近，那里的密度（因此?...

超临界流体萃取（SFE）和干燥（SCD）方法被很好地建立在广泛的实际应用，特别是在食品工业和石油工业，也可在化学合成，分析和材料的加工。1-6使用干燥或提取介质在高于其临界点条件往往是更快，更清洁和更有效的比传统的（液体）的技术，并具有可通过操作条件稍作调整相对于高度可调的流体的溶剂化功率的额外优点3,7一种简单的方法理学包括三个基本步骤。第一步是露出其包含在其液体中的目标杂质化合物来适当选择理学流体的固体（或者液体）的原料（或接近液体超临界相），在那里它的高密度对应于高（也许选择性7）溶剂功率相对于所述靶物种。 Ť他第二步骤加热和压缩上述所选理学流体的临界点，系统中的封闭容器，以使流体和其溶解靶物种不通过相界这可能导致分离。最后一步是缓慢降低理学流体的真空压力在高于临界温度的温度下，使含有目标物种逃脱，再次没有遇到一个相界或沿途的任何有害的表面张力作用的流体溶液。 起始原料为左耗尽目标物种的，并且可以进行迭代处理，如果有必要的。在超临界流体萃取的情况下，目标溶质种类是所需产物，并从供进一步使用的解决方案。8,9-收集在其他情况下，将干燥的或纯化的起始材料是期望的产物，并将所提取的杂质被丢弃。这后一种情况下，这里所指作为理学方法，被发现是一种有效的策略，高表面积，微孔材料，如金属 - 有机骨架（MOFs），其中，在真空下传统的热处理方法在许多情况下，在清除孔不充分的预处理所有的不速之客，或导致孔隙坍塌。10二氧化碳理学博士（CSCD）处理现在是一个常规的后期合成的过程MOFs材料，11导致增加氮可接触的表面面积比高达1000％未经处理的材料12其他的改进，如在催化活性。13其他值得注意的超临界流体的应用是作为一种广泛可调谐介质进行化学反应，14-16超临界流体色谱（SCFC）6,17,18和合成气凝胶和先进复合材料。19- 22 对于干燥应用，理学博士流体是基于两个标准来选择:一）接近它的临界点到环境的条件（为方便起见，并降低能源成本或处理复杂性）和b）其溶剂化功率相对于所述靶物种。二氧化碳（CO 2）已被证明是在许多应用中方便理学流体，因为它是无毒的，不可燃的，并且价格便宜，并且可以进行调节，以表现出高的溶剂化功率朝向一些普通的有机靶物种在其近液体的状态（在&lt;10兆帕的压力和温度273-323 K）1-3,7-9其他常见的超临界溶剂（或共溶剂）包括水（跨越一个显着的其环境和超临界状态之间溶剂性能范围23），丙酮，乙烯，甲醇，乙醇，和乙烷，覆盖从极性（质子和非质子传递）到非极性的，并具有对环境条件相对临界点附近的频谱。 二氧化碳是迄今为止最常用理学流体。在建立CSCD方法中，反应性的原料不是抑制因子，因为二氧化碳是只有非常弱的温度接近它的临界点的反应。然而，由于其在水或CO 2存在强的反应，除了在加热下其（可能故意量身定做）不稳定某些类的材料，如所谓的复合氢化物（ 例如 ，铝氢化物和硼氢化物）在处理本独特的挑战24-26此外，还有在这样的材料如高密度的储氢化合物，27-30极大国际兴趣，因此，可以在纳米结构和/或多孔的品种31-33。对于这样的反应性的，不稳定的，纳米结构材料的有效的净化，理学的方法是有前途的策略。34所述理学流体必须使用具有适用于穿入窄空腔分子直径小并且还具有高的溶剂化功率朝向目标杂质，WHI勒剩余朝向起始材料本身不反应。这里，利用超临界氮气（N 2）作为用于这种提取和特别干燥应用提供有效的流体呈现。具体超临界氮气干燥（NSCD）方法是下面描述的γ相镁硼氢化其中目标种类包括二硼烷和正丁基的化合物（类似但不专门识别为正丁烷）的纯化。下面的协议可以很容易地修改一般扩展到其他超临界氮气干燥或提取过程。

<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.

碱金属和碱土金属硼氢化物是潜在的储氢材料，其在分解。27,29其他分解产物递送气态氢的含量大，如乙硼烷也有时被解吸的气体中检测到，但其来源没有先验明确;有可能它们是纯相的分解产品，但也可以是杂质的杂质反应或产物剩从化学合成。35镁硼氢化的多孔相（γ-Mg系（BH 4）2）表现出既具有高比表面积（&gt; 1,000米2 g -1）以上和氢。36及其脱?...

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

氮气是用于萃取或干燥过程的有效的超临界流体，由于其小的分子尺寸，高密度在近液体超临界状态，和化学惰性。我们提出了一个超临界氮气干燥协议用于净化处理的反应性的，多孔的材料。

超临界氮处理的活性多孔材料的净化

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

Universidad de Cartagena UDEC

Research

JoVE Journal

Chemistry

14.7K 次观看.  Empa, Swiss Federal Laboratories for Materials Science and Technology. 氮气是用于萃取或干燥过程的有效的超临界流体，由于其小的分子尺寸，高密度在近液体超临界状态，和化学惰性。我们提出了一个超临界氮气干燥协议用于净化处理的反应性的，多孔的材料。 

视频: Supercritical Nitrogen Processing for the Purification of Reactive Porous Materials

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.

通过快速超临界萃取法制备二氧化硅气凝胶巨石

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

科研

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.

对磷酸增强富集制备高度多孔配位聚合物涂层的孔聚合物石柱的

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.

一氧化氮气体防治害虫实验室熏蒸程序

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

环境科学

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.

在线含硫化合物在复杂油气矩阵氮分析

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.

微波热解法制备了更高氮素/氧螯合吸附的生物物质基介孔碳对 cu (ii) 的研究

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.

基于14NH 4 + /4+ 15NH 4= 通过顺序转换为 N2O 的分析，测量异化硝酸盐降低至铵的潜在率

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.

合成纳米碳和二氧化硅矩阵的表面性能

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

High-Temperature and High-Pressure In situ Magic Angle Spinning Nuclear Magnetic Resonance Spectroscopy

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There exists a drive to characterize materials under conditions relevant to the chemical process of interest. To address this, in situ high-temperature, high-pressure MAS NMR methods have been developed to enable the observation of chemical interactions over a range of pressures (vacuum to several hundred bar) and temperatures (well below 0 &#176;C to 250 &#176;C). Further, the chemical identity of the samples can be comprised of solids, liquids, and gases or mixtures of the three. The method incorporates all-zirconia NMR rotors (sample holder for MAS NMR) which can be sealed using a threaded cap to compress an O-ring. This rotor exhibits great chemical resistance, temperature compatibility, low NMR background, and can withstand high pressures. These combined factors enable it to be utilized in a wide range of system combinations, which in turn permit its use in diverse fields as carbon sequestration, catalysis, material science, geochemistry, and biology. The flexibility of this technique makes it an attractive option for scientists from numerous disciplines.

The molecular structures and dynamics of solids, liquids, gases, and mixtures are of critical interest to diverse scientific fields. High-temperature, high-pressure in situ MAS NMR enables detection of the chemical environment of constituents in mixed phase systems under tightly controlled chemical environments.

高温高压原位魔角旋转核磁共振光谱

Nuclear magnetic resonance (NMR) spectroscopy represents an important technique to understand the structure and bonding environments of molecules. There ...

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.

低压氨合成

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 ...

生物工程

Versatile Home-Built Microwave-Assisted System for Peptide Synthesis

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.

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

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