对美国化学学会石油研究基金的捐助者的承认是对这项研究的部分支持。我们感谢国家科学基金会 (CHE-0619275 和 CHE-0963165) 的革新和仪器赠款, 支持这项研究。

1. 从混合物中分离芳香醛的标准协议。例子: 从1:1 混合物与茴香醛分离丁酸苄酯。
<ol><li>将 175 ul 的茴香醛和 250 ul 的丁酸苄酯溶解在5毫升甲醇中, 并将溶液转移到部位漏斗上。 注意: 亚硫酸氢钠可以产生二氧化硫气体, 因此该协议应进行适当的通风, 如通风罩。</li>
	<li>加入1毫升饱和水亚硫酸氢钠, 并大力摇动大约三十年代。</li>
	<li>加入25毫升去离子水和25毫升10% 乙酸乙酯/hexanes, 并大力摇动。</li>
	<li>分隔图层。用无水硫酸镁干燥有机层。过滤解决方案, 以去除硫酸镁和集中在真空使用旋转蒸发器。</li>
</ol>2. 从混合物中分离脂肪醛和酮。例子: 从1:1 混合物与 Benzylacetone 分离丁酸苄酯。
<ol><li>在10毫升的甲基酰胺中溶解 213 ul 的 benzylacetone 和 250 ul 的丁酸苄酯, 并将溶液转移到部位漏斗上。 注意: 亚硫酸氢钠可以产生二氧化硫气体, 因此该协议应进行适当的通风, 如通风罩。</li>
	<li>加入25毫升饱和水亚硫酸氢钠, 并大力摇动大约三十年代。</li>
	<li>加入25毫升去离子水和25毫升10% 乙酸乙酯/hexanes, 并大力摇动。</li>
	<li>分隔图层。将水层返回部位漏斗, 加入25毫升10% 乙基醋酸盐/hexanes, 并大力摇动。排出水层, 将有机层留在部位漏斗中。将以前的有机层添加回部位漏斗。</li>
	<li>用去离子水洗三次组合的有机层 (每洗涤10毫升)。用无水硫酸镁干燥有机层。过滤解决方案, 以去除硫酸镁和集中在真空使用旋转蒸发器。</li>
</ol>3. 从含有烯烃的混合物中分离醛。例子: 从1:1 混合物与香茅醛物分离丁酸苄酯。
<ol><li>在10毫升的甲基酰胺中溶解 255 ul 的香茅醛物和 250 ul 的丁酸苄酯, 并将溶液转移到部位漏斗上。 注意: 亚硫酸氢钠可以产生二氧化硫气体, 因此该协议应进行适当的通风, 如通风罩。</li>
	<li>加入25毫升饱和水亚硫酸氢钠, 并大力摇动大约三十年代。</li>
	<li>加入25毫升去离子水和25毫升的 hexanes, 并大力摇动。</li>
	<li>分隔图层。将水层返回部位漏斗, 加入25毫升 hexanes, 用力摇动。排出水层, 将有机层留在部位漏斗中。将以前的有机层添加回部位漏斗。</li>
	<li>用去离子水洗三次组合的有机层 (每洗涤10毫升)。用无水硫酸镁干燥有机层。过滤解决方案, 以去除硫酸镁和集中在真空使用旋转蒸发器。</li>
</ol>4. 从混合物中重新分离醛类。例子: 从1:1 混合物中分离胡椒与丁酸苄酯。
<ol><li>在5毫升甲醇中溶解217毫克的胡椒和 250 ul 的丁酸苄酯, 并将溶液转移到部位漏斗上。 注意: 亚硫酸氢钠可以产生二氧化硫气体, 因此, 该协议应进行适当的通风, 如在油烟机。</li>
	<li>加入1毫升饱和水亚硫酸氢钠, 并大力摇动大约三十年代。</li>
	<li>加入25毫升去离子水和25毫升10% 乙酸乙酯/hexanes, 并大力摇动。</li>
	<li>分隔图层。将水层回流回部位漏斗。<ol>
<li>可选: 用25毫升10% 乙酸乙酯/hexanes 洗涤水层, 除去少量残留的丁酸苄酯。</li>
	</ol>
</li>
	<li>加入25毫升醋酸乙酯, 然后加入50% 氢氧化钠, 直到 ph 条指示 ph 值为12。用力摇动。 注意: 在这一步骤中已经观察到气体的演化, 并可能导致压力积聚。一定要正确地排出部位漏斗。扩大这一过程将使气体演化更加明显。请小心。</li>
	<li>分隔图层。将水层返回部位漏斗, 加入25毫升醋酸乙酯。用力摇动。</li>
	<li>分隔图层。从上一步将有机层与有机层结合起来。用无水硫酸镁将有机复合层干燥。过滤解决方案, 以去除硫酸镁和集中在真空使用旋转蒸发器。</li>
</ol>

<ol>
	<li>Boucher, M. M., Furigay, M. H., Quach, P. K., Brindle, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Liquid-Liquid+Extraction+Protocol+for+the+Removal+of+Aldehydes+and+Highly+Reactive+Ketones+from+Mixtures.">Liquid-Liquid Extraction Protocol for the Removal of Aldehydes and Highly Reactive Ketones from Mixtures.</a> Org. Process Res. Dev. 21 (9), 1394-1403 (2017).</li><li>Lauer, G. G., Pratt, R. S., Wilson, W. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Separation+of+Aldehydes+and+Ketones.">Separation of Aldehydes and Ketones.</a> , (1951).</li><li>Hsu, W. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Separation of Aldehydes from Ketones via Acid-Catalyzed Cyclotrimerization of the Aldehyde. , 4701561 (1987).</li><li>Schreiber, R. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Process+for+Separating+Aldehydes+and+Ketones.">Process for Separating Aldehydes and Ketones.</a> , (1942).</li><li>Bludworth, J. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Separation+of+Aldehyde-Ketone+Mixtures.">Separation of Aldehyde-Ketone Mixtures.</a> , (1944).</li><li>Masilamani, D., Manahan, E. H., Vitrone, J., Rogic, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organic+Reactions+of+Sulfur+Dioxide.+Reactions+with+Nucleophilic+Double+Bonds+Leading+to+the+Isomerization,+Aromatization,+Selective+Hydrogen-Deuterium+Exchange,+and+Electron-Transfer+Proceses.">Organic Reactions of Sulfur Dioxide. Reactions with Nucleophilic Double Bonds Leading to the Isomerization, Aromatization, Selective Hydrogen-Deuterium Exchange, and Electron-Transfer Proceses.</a> J. Org. Chem. 48 (25), 4918-4931 (1983).</li><li>Masilamani, D., Rogic, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Organic+Reactions+of+Sulfur+Dioxide.+4.+A+Facile+Regiospecific+Hydrogen-Deuterium+Exchange+in+Olefins.+Consequence+of+the+Intermediacy+of+Allylic+Sulfinic+Acids+in+the+Ene+Reaction+of+Sulfur+Dioxide+with+Double+Bonds.">Organic Reactions of Sulfur Dioxide. 4. A Facile Regiospecific Hydrogen-Deuterium Exchange in Olefins. Consequence of the Intermediacy of Allylic Sulfinic Acids in the Ene Reaction of Sulfur Dioxide with Double Bonds.</a> J. Am. Chem. Soc. 100 (14), 4634-4635 (1978).</li><li>Makitra, R. G., Kal'muk, S. D., Bryk, D. V., Polyuzhin, I. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Factors+Controlling+Sulfur+Dioxide+Solubilities+in+Organic+Solvents.">Factors Controlling Sulfur Dioxide Solubilities in Organic Solvents.</a> Russ. J. Inorg. Chem. 55 (8), 1322-1329 (2010).</li><li>van Dam, M. H. H., Lamine, A. S., Roizard, D., Lochon, P., Roizard, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Selective+Sulfur+Dioxide+Removal+Using+Organic+Solvents.">Selective Sulfur Dioxide Removal Using Organic Solvents.</a> Ind. Eng. Chem. Res. 36 (11), 4628-4637 (1997).</li><li>Li, H., Jiao, X., Chen, W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Solubility+of+Sulphur+Dioxide+in+Polar+Organic+Solvents.">Solubility of Sulphur Dioxide in Polar Organic Solvents.</a> Phys. Chem. Liq. 52 (2), 349-353 (2014).</li><li>Trost, B. M., Brindle, C. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Direct+Catalytic+Asymmetric+Aldol+Reaction.">The Direct Catalytic Asymmetric Aldol Reaction.</a> Chem. Soc. Rev. 39 (5), 1600 (2010).</li></ol>

作者没有什么可透露的。

最初尝试使用亚硫酸氢反应作为一种方法来去除醛使用典型的两相萃取, 导致极低的去除水平。我们假设, 反应是不够快, 在非常有限的时间内发生的两层接触。为了增加反应物之间的接触, 我们开发了一个两阶段萃取协议, 在这种条件下, 首先使用水混溶溶剂, 使反应物在引入不溶溶剂之前有足够的混合。引入不相容的溶剂, 然后允许分离的带电亚硫酸氢合物从带电有机成分。该协议的关键步骤是使...

混合物组分的分离对制备纯材料是必不可少的。本文介绍的方法允许从其他有机分子中简便地分离醛和 sterically 不受阻碍的循环和甲基酮1。该技术依赖亚硫酸氢与羰基基团的反应性, 创建一个可分离成水层的带电加合物, 而其他组分则分离成不相容的有机层。在亚硫酸氢和羰基之间实现反应性的关键是使用一种混溶溶剂, 这使得在分离之前的反应发生在不同的阶段。如果没有加入混溶溶剂的最小分离, 大概是由于亲水性亚硫酸氢和疏水性有机物之间的接触差。
这种分离方法的优点是能方便地进行纯化。液-液萃取是一种简单的操作, 可以大规模地进行。替代纯化技术, 如柱层析, 是昂贵得多, 耗时, 并具有挑战性的大规模执行, 需要充分的差异, 在极性方面的成分。通过再结晶或蒸馏提纯, 需要对混合物组分的溶解度或沸点进行充分的分异。由于亚硫酸氢提取依赖于醛和酮羰基基团反应性的差异, 具有相似溶解度、沸点或极性的化合物可以有效地分离。其他化学分离方法存在选择性地分离醛和酮从混合物, 例如, 选择性形成肟2, 循环缩醛产物3, 或缩4 形成。这些方法需要额外的步骤来分离形成的物种与混合物, 因为产品不是水溶性的, 因此不能用简单的萃取协议分离。醛氧化形成可移动羧酸是另一种报告的技术5, 但所需的氧化步骤是低于 chemoselective 的温和亚硫酸氢条件, 并要求使用氧气气体和钴催化剂。
此方法适用于不包含这些功能组的分子的分离醛 (图 1) 和 sterically 不受阻碍的循环和甲基酮 (图 2)。特别是反应性酮, 如α-酮酯也被删除使用这个过程。烷烃, 烯烃, 二烯烃, 炔烃, 酯, 酰胺, 羧酸, 烷基卤化物, 醇, 酚, 腈, 苄基氯化物, 环氧化合物, 苯胺, 缩醛产物, 和稍受阻, α, β不饱和, 或芳酮都不活跃在条件下并且可以与混合物中的醛或反应性酮组分 (图2和图形 3) 分开。例如, 乙基酮或α取代的循环酮受到了充分的阻碍, 因此可从醛类和更多反应性酮中分离出来。当使用烯烃时, 将己烷推荐为不溶溶剂, 以防止亚硫酸氢溶液中的二氧化硫造成不必要的分解。亚硫酸氢萃取协议的官能团相容性非常广泛, 因此适用于极宽范围的分离, 如果要从混合物中分离的羰基污染物要么是醛或不受阻碍甲基或循环酮。没有反应的酮在这些情况下不会与亚硫酸氢反应, 因此不被去除。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>sodium bisulfite</td>
			<td>Fisher</td>
			<td>AC419440010&#160;</td>
			<td>1 kg</td>
		</tr>
		<tr>
			<td>benzyl butyrate</td>
			<td>Fisher</td>
			<td>AAB2424130&#160;</td>
			<td>250 g</td>
		</tr>
		<tr>
			<td>anisaldehyde</td>
			<td>Fisher</td>
			<td>AC104801000&#160;</td>
			<td>100 mL</td>
		</tr>
		<tr>
			<td>magnesium sulfate</td>
			<td>Fisher</td>
			<td>M65-500&#160;</td>
			<td>500 g</td>
		</tr>
		<tr>
			<td>ethyl acetate</td>
			<td>Fisher</td>
			<td>E195-4&#160;</td>
			<td>4 L</td>
		</tr>
		<tr>
			<td>hexanes</td>
			<td>Fisher</td>
			<td>H292-4&#160;</td>
			<td>4 L</td>
		</tr>
		<tr>
			<td>methanol&#160;</td>
			<td>Fisher</td>
			<td>A456-1&#160;</td>
			<td>1 L</td>
		</tr>
		<tr>
			<td>dimethylformamide</td>
			<td>Fisher</td>
			<td>D119-1&#160;</td>
			<td>1 L</td>
		</tr>
		<tr>
			<td>citronellal</td>
			<td>Fisher</td>
			<td>AAL15753AE&#160;</td>
			<td>100 mL</td>
		</tr>
		<tr>
			<td>benzylacetone&#160;</td>
			<td>Fisher</td>
			<td>AC105832500&#160;</td>
			<td>250 mL</td>
		</tr>
		<tr>
			<td>deionized water</td>
			<td>Fisher</td>
			<td>BP28194&#160;</td>
			<td>4 L</td>
		</tr>
		<tr>
			<td>piperonal&#160;</td>
			<td>Sigma-Aldrich</td>
			<td>P49104-25G</td>
			<td>25 G</td>
		</tr>
		<tr>
			<td>sodium hydroxide</td>
			<td>Fisher</td>
			<td>S318-1&#160;</td>
			<td>1 kg</td>
		</tr>
		<tr>
			<td>separatory funnel with cap</td>
			<td>Fisher</td>
			<td>10-437-5B&#160;</td>
			<td>125 mL</td>
		</tr>
		<tr>
			<td>ring stand</td>
			<td>Fisher</td>
			<td>03-422-215</td>
			<td>3 aluminum rods</td>
		</tr>
		<tr>
			<td>ring clamp</td>
			<td>Fisher</td>
			<td>12-000-104&#160;</td>
			<td>5 cm</td>
		</tr>
		<tr>
			<td>cork ring</td>
			<td>Fisher</td>
			<td>07-835AA&#160;</td>
			<td>8 cm outer dimension</td>
		</tr>
		<tr>
			<td>round bottom flask</td>
			<td>Fisher</td>
			<td>31-501-107&#160;</td>
			<td>100 mL</td>
		</tr>
		<tr>
			<td>rotary evaporator with accessories</td>
			<td>Fisher</td>
			<td>05-000-461&#160;</td>
			<td>cold trap bondenser</td>
		</tr>
		<tr>
			<td>bump trap 14/20 joint</td>
			<td>Fisher</td>
			<td>CG132201</td>
			<td>14/20 joint</td>
		</tr>
		<tr>
			<td>funnel</td>
			<td>Fisher</td>
			<td>05-555-6&#160;</td>
			<td>organic solvent compatible</td>
		</tr>
		<tr>
			<td>cotton</td>
			<td>Fisher</td>
			<td>22-456-881</td>
			<td>non-sterile</td>
		</tr>
		<tr>
			<td>glass pipets</td>
			<td>Fisher</td>
			<td>13-678-20A&#160;</td>
			<td>borosilicate 5.75&#34;</td>
		</tr>
		<tr>
			<td>two 250 microliter syringes</td>
			<td>Fisher</td>
			<td>14-813-69&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>4 erlenmeyer flasks</td>
			<td>Fisher</td>
			<td>10-040D&#160;</td>
			<td>125 mL</td>
		</tr>
		<tr>
			<td>fume hood&#160;</td>
			<td>Fisher</td>
			<td>13-118-370&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>nitrile gloves</td>
			<td>Fisher</td>
			<td>19-149-863B&#160;</td>
			<td>medium</td>
		</tr>
		<tr>
			<td>safety goggles</td>
			<td>Fisher</td>
			<td>17-377-403&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>spatula</td>
			<td>Fisher</td>
			<td>14-357Q</td>
			<td></td>
		</tr>
		<tr>
			<td>balance</td>
			<td>Fisher</td>
			<td>01-912-403&#160;</td>
			<td>120 g capacity</td>
		</tr>
	</tbody>
</table>

separation of aldehydes and reactive ketones from mixtures using a bisulfite extraction protocol

有机化合物的提纯是常规合成作业的重要组成部分。通过生成带电结构将污染物移到水层中的能力提供了利用萃取作为一种简单的净化技术的机会。通过将混溶有机溶剂与饱和亚硫酸氢钠结合使用, 可以成功地将醛类和反应性酮转化为带电的亚硫酸氢加合物, 然后将其与混合物的其他有机成分分离。介绍一种不相容的有机层。在这里, 我们描述了一个简单的协议, 以去除醛, 包括 sterically 受阻的新戊二醛和一些酮, 从化学混合物。酮可以分离, 如果他们是 sterically 不受阻碍的循环或甲基酮。对于脂肪族醛类和酮类, 甲基酰胺被用作混溶溶剂, 以提高去除率。亚硫酸氢的加入反应可以通过碱化的水层来逆转, 从而使混合物的反应羰基组分重新分离。

用于醛去除的过程1用于芳香醛。过程2, 其中甲基酰胺用作混溶溶剂, 应用于脂肪族醛和酮。过程2还应用于不完全溶于甲醇的混合物。利用1H 核磁共振积分分析和质量恢复率分析了从每种协议获得的材料的纯度。典型的纯度和恢复大于 95% (图 1)。成功的分离取决于醛或酮组件 (图 4和...

Watch this Scientific Journal Video about Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol at JoVE.com

Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol

用亚硫酸氢萃取协议分离混合物中的醛和反应性酮

在这里, 我们提出了一个协议, 从混合物中去除醛和反应酮的液体-液体萃取协议直接与饱和亚硫酸氢钠在混溶溶剂。这个组合协议是快速和轻便的执行。醛或酮可以通过水层的碱化重新分离。

The purification of organic compounds is an essential component of routine synthetic operations. The ability to remove contaminants into an aqueous layer ...

separation-aldehydes-reactive-ketones-from-mixtures-using-bisulfite

Universidad de Cartagena UDEC

Research

Education

JoVE Journal

JoVE Core

Chemistry

Introduction: Matter and Measurement

SCIENTISTS IN ACTION

33.8K 次观看.  Trinity College. 在这里, 我们提出了一个协议, 从混合物中去除醛和反应酮的液体-液体萃取协议直接与饱和亚硫酸氢钠在混溶溶剂。这个组合协议是快速和轻便的执行。醛或酮可以通过水层的碱化重新分离。

视频: Separation of Aldehydes and Reactive Ketones from Mixtures Using a Bisulfite Extraction Protocol

A Simple and Rapid Protocol for Measuring Neutral Lipids in Algal Cells Using Fluorescence

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal fermentation processes and screening for new oil-rich strains requires a fast and reliable protocol for determination of intracellular lipid content. Current practices rely largely on gravimetric methods to determine oil content, techniques developed decades ago that are time consuming and require large sample volumes. In this paper, Nile Red, a fluorescent dye that has been used to identify the presence of lipid bodies in numerous types of organisms, is incorporated into a simple, fast, and reliable protocol for measuring the neutral lipid content of Auxenochlorella protothecoides, a green alga. The method uses ethanol, a relatively mild solvent, to permeabilize the cell membrane before staining and a 96 well micro-plate to increase sample capacity during fluorescence intensity measurements. It has been designed with the specific application of monitoring bioprocess performance. Previously dried samples or live samples from a growing culture can be used in the assay.

A simple protocol to determine the neutral lipid content of algal cells using a Nile Red staining procedure is described. This time-saving technique offers an alternative to traditional gravimetric-based lipid quantification protocols. It has been designed for the specific application of monitoring bioprocess performance.

一种简单快速的协议用荧光测量中性脂肪在藻细胞

Algae are considered excellent candidates for renewable fuel sources due to their natural lipid storage capabilities. Robust monitoring of algal ...

科研

化学

Confocal Imaging of Confined Quiescent and Flowing Colloid-polymer Mixtures

The behavior of confined colloidal suspensions with attractive interparticle interactions is critical to the rational design of materials for directed assembly1-3, drug delivery4, improved hydrocarbon recovery5-7, and flowable electrodes for energy storage8. Suspensions containing fluorescent colloids and non-adsorbing polymers are appealing model systems, as the ratio of the polymer radius of gyration to the particle radius&#160;and concentration of polymer control the range and strength of the interparticle attraction, respectively. By tuning the polymer properties and the volume fraction of the colloids, colloid fluids, fluids of clusters, gels, crystals, and glasses can be obtained9.&#160;Confocal microscopy, a variant of fluorescence microscopy, allows an optically transparent and fluorescent sample to be imaged with high spatial and temporal resolution in three dimensions. In this technique, a small pinhole or slit blocks the emitted fluorescent light from regions of the sample that are outside the focal volume of the microscope optical system. As a result, only a thin section of the sample in the focal plane is imaged. This technique is particularly well suited to probe the structure and dynamics in dense colloidal suspensions at the single-particle scale: the particles are large enough to be resolved using visible light and diffuse slowly enough to be captured at typical scan speeds of commercial confocal systems10. Improvements in scan speeds and analysis algorithms have also enabled quantitative confocal imaging of flowing suspensions11-16,37.&#160;In this paper, we demonstrate confocal microscopy experiments to probe the confined phase behavior and flow properties of colloid-polymer mixtures. We first prepare colloid-polymer mixtures that are density- and refractive-index matched. Next, we report a standard protocol for imaging quiescent dense colloid-polymer mixtures under varying confinement in thin wedge-shaped cells. Finally, we demonstrate a protocol for imaging colloid-polymer mixtures during microchannel flow.

Confocal microscopy is used to image quiescent and flowing colloid-polymer mixtures, which are studied as model systems for attractive suspensions. Image analysis algorithms are used to calculate structural and dynamic metrics for the colloidal particles that measure changes due to geometric confinement.

密闭静态和流动胶体聚合物混合物的共聚焦成像

The behavior of confined colloidal suspensions with attractive interparticle interactions is critical to the rational design of materials for directed ...

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.

Nitrogen is an effective supercritical fluid for extraction or drying processes due to its small molecular size, high density in the near-liquid supercritical regime, and chemical inertness. We present a supercritical nitrogen drying protocol for the purification treatment of reactive, porous materials.

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. ...

Preparation of Biopolymer Aerogels Using Green Solvents

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers (gelatin, agar, cellulose), only recently have biomasses been recognized as an abundant source of chemically diverse macromolecules for functional aerogel materials. Biopolymer aerogels (pectin, alginate, chitosan, cellulose, etc.) exhibit both specific inheritable functions of starting biopolymers and distinctive features of aerogels (80-99% porosity and specific surface up to 800 m2/g). This synergy of properties makes biopolymer aerogels promising candidates for a wide gamut of applications such as thermal insulation, tissue engineering and regenerative medicine, drug delivery systems, functional foods, catalysts, adsorbents and sensors. This work demonstrates the use of pressurized carbon dioxide (5 MPa) for the ionic cross linking of amidated pectin into hydrogels. Initially a biopolymer/salt dispersion is prepared in water. Under pressurized CO2 conditions, the pH of the biopolymer solution is lowered to 3 which releases the crosslinking cations from the salt to bind with the biopolymer yielding hydrogels. Solvent exchange to ethanol and further supercritical CO2 drying (10 - 12 MPa) yield aerogels. Obtained aerogels are ultra-porous with low density (as low as 0.02 g/cm3), high specific surface area (350 - 500 m2/g) and pore volume (3 - 7 cm3/g for pore sizes less than 150 nm).

A new way for the production of biopolymer-based aerogels by carbon dioxide (CO2) induced gelation is shown. The technique utilizes pressurized carbon dioxide (5 MPa) for the production of biopolymer hydrogels and supercritical CO2 (12 MPa) to convert gels into aerogels. The only solvents needed besides CO2 are water and ethanol.

生物聚合物气凝胶制备使用绿色溶剂

Although the first reports on aerogels made by Kistler1 in the 1930s dealt with aerogels from both inorganic oxides (silica and others) and biopolymers ...

Sulfate Separation by Selective Crystallization with a Bis-iminoguanidinium Ligand

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, 1,4-benzene-bis(iminoguanidinium) (BBIG), is demonstrated. The ligand is synthesized as the chloride salt (BBIG-Cl) by in situ imine condensation of terephthalaldehyde with aminoguanidinium chloride in water, followed by crystallization as the sulfate salt (BBIG-SO4). Alternatively, BBIG-Cl is synthesized ex situ in larger scale from ethanol. The sulfate separation ability of the BBIG ligand is demonstrated by selective and quantitative crystallization of sulfate from seawater. The ligand can be recycled by neutralization of BBIG-SO4 with aqueous NaOH and crystallization of the neutral bis-iminoguanidine, which can be converted back into BBIG-Cl with aqueous HCl and reused in another separation cycle. Finally, 35S-labeled sulfate and &#946; liquid scintillation counting are employed for monitoring the sulfate concentration in solution. Overall, this protocol will instruct the user in the necessary skills to synthesize a ligand, employ it in the selective crystallization of sulfate from aqueous solutions, and quantify the separation efficiency.

A protocol for in situ aqueous synthesis of a bis(iminoguanidinium) ligand and its utilization in selective separation of sulfate is presented.

分离硫酸选择性结晶用双 -  iminoguanidinium配体

A simple and effective method for selective sulfate separation from aqueous solutions by crystallization with a bis-guanidinium ligand, ...

Capillary Electrophoresis to Monitor Peptide Grafting onto Chitosan Films in Real Time

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. Compared to other analytical separation techniques, such as chromatography, CE is cheap, robust and effectively requires no sample preparation (for a number of complex natural matrices or polymeric samples). CE is fast and can be used to follow the evolution of mixtures in real time (e.g., chemical reaction kinetics), as the signals observed for the separated compounds are directly proportional to their quantity in solution.
Here, the efficiency of CE is demonstrated for monitoring the covalent grafting of peptides onto chitosan films for subsequent biomedical applications. Chitosan&#39;s antimicrobial and biocompatible properties make it an attractive material for biomedical applications such as cell growth substrates. Covalently grafting the peptide RGDS (arginine - glycine - aspartic acid - serine) onto the surface of chitosan films aims at improving cell attachment. Historically, chromatography and amino acid analysis have been used to provide a direct measurement of the amount of grafted peptide. However, the fast separation and absence of sample preparation provided by CE enables equally accurate yet real-time monitoring of the peptide grafting process. CE is able to separate and quantify the different components of the reaction mixture: the (non-grafted) peptide and the chemical coupling agents. In this way the use of CE results in improved films for downstream applications.
The chitosan films were characterized through solid-state NMR (nuclear magnetic resonance) spectroscopy. This technique is more time-consuming and cannot be applied in real time, but yields a direct measurement of the peptide and thus validates the CE technique.

Free solution capillary electrophoresis is a fast, cheap and robust analytical method that enables the quantitative monitoring of chemical reactions in real time. Its utility for rapid, convenient and precise analysis is demonstrated here through analysis of covalent peptide grafting onto chitosan films for improved cell adhesion.

毛细管电泳监视肽接枝壳聚糖膜实时

Free-solution capillary electrophoresis (CE) separates analytes, generally charged compounds in solution through the application of an electric field. ...

A Protocol for Safe Lithiation Reactions Using Organolithium Reagents

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents warrants proper technique, thorough training, and proper personal protective equipment. To aid in the training of researchers using organolithium reagents, a thorough, step-by-step protocol for the safe and effective use of tert-butyllithium on an inert gas line or within a glovebox is described. As a model reaction, preparation of lithium tert-butyl amide by the reaction of tert-butyl amine with one equivalent of tert-butyl lithium is presented.

The safe and proper use of organolithium reagents is described.

使用有机锂试剂的一个协议安全的锂化反应

Organolithium reagents are powerful tools in the synthetic chemist&#39;s toolbox. However, the extreme pyrophoric nature of the most reactive reagents ...

Fabrication and Testing of Catalytic Aerogels Prepared Via Rapid Supercritical Extraction

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three preparation methods are described: (a) the incorporation of metal salts into silica or alumina wet gels using an impregnation method; (b) the incorporation of metal salts into alumina wet gels using a co-precursor method; and (c) the addition of metal nanoparticles directly into a silica aerogel precursor mixture. The methods utilize a hydraulic hot press, which allows for rapid (&#60;6 h) supercritical extraction and results in aerogels of low density (0.10 g/mL) and high surface area (200-800 m2/g). While the work presented here focuses on the use of copper salts and copper nanoparticles, the approach can be implemented using other metal salts and nanoparticles. A protocol for testing the three-way catalytic ability of these aerogels for automotive pollution mitigation is also presented. This technique uses custom-built equipment, the Union Catalytic Testbed (UCAT), in which a simulated exhaust mixture is passed over an aerogel sample at a controlled temperature and flow rate. The system is capable of measuring the ability of the catalytic aerogels, under both oxidizing and reducing conditions, to convert CO, NO and unburned hydrocarbons (HCs) to less harmful species (CO2, H2O and N2). Example catalytic results are presented for the aerogels described.

Here we present protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms. Methods for preparing materials using copper salts and copper-containing nanoparticles are featured. Catalytic testing protocols demonstrate the effectiveness of these aerogels for three-way catalysis applications.

快速超临界萃取制备催化气凝胶的制备与试验研究

Protocols for preparing and testing catalytic aerogels by incorporating metal species into silica and alumina aerogel platforms are presented. Three ...

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species

&#945;-Functionalization of ketones via umpolung of enolates by hypervalent iodine reagents is an important concept in synthetic organic chemistry. Recently, we have developed a two-step strategy for ketone enolate umpolung that has enabled the development of methods for chlorination, azidation, and amination using azoles. In addition, we have developed C-C bond&#8211;forming arylation and allylation reactions. At the heart of these methods is the preparation of the intermediate and highly reactive enolonium species prior to addition of a reactive nucleophile. This strategy is thus reminiscent of the preparation and use of metal enolates in classical synthetic chemistry. This strategy allows the use of nucleophiles that would otherwise be incompatible with the strongly oxidizing hypervalent iodine reagents. In this paper we present a detailed protocol for chlorination, azidation, N-heteroarylation, arylation, and allylation. The products include motifs prevalent in medicinally active products. This article will greatly assist others in using these methods.

A two step one-pot protocol for the umpolung of ketone enolates to enolonium species and addition of a nucleophile to the &#945;-position is described. Nucleophiles include chloride, azide, azoles, allyl-silanes, and aromatic compounds.

Enolonium 种极性转换酮功能化的两步协议

&#945;-Functionalization of ketones via umpolung of enolates by hypervalent iodine reagents is an important concept in synthetic organic chemistry. ...

Reactive Inkjet Printing and Propulsion Analysis of Silk-based Self-propelled Micro-stirrers

In this study, a protocol for using reactive inkjet printing to fabricate enzymatically propelled silk swimmers with well-defined shapes is reported. The resulting devices are an example of self-propelled objects capable of generating motion without external actuation and have potential applications in medicine and environmental sciences for a variety of purposes ranging from micro-stirring, targeted therapeutic delivery, to water remediation (e.g., cleaning oil spills). This method employs reactive inkjet printing to generate well-defined small-scale solid silk structures by converting water soluble regenerated silk fibroin (silk I) to insoluble silk fibroin (silk II). These structures are also selectively doped in specific regions with the enzyme catalase in order to produce motion via bubble generation and detachment. The number of layers printed determines the three-dimensional (3D) structure of the device, and so here the effect of this parameter on the propulsive trajectories is reported. The results demonstrate the ability to tune the motion by varying the dimensions of the printed structures.

This protocol demonstrates the ability to utilize reactive inkjet printing to print self-motile biocompatible and environmentally friendly micro-stirrers for use in biomedical and environmental applications.

基于丝绸的自行式微搅拌器的反应式喷墨打印及推进分析

In this study, a protocol for using reactive inkjet printing to fabricate enzymatically propelled silk swimmers with well-defined shapes is reported. The ...