Noi riconosciamo con gratitudine il sostegno finanziario fornito dal National Key Research & Development Program di Ministero della scienza e della tecnologia della Cina (2016YFB0600305), Fondazione nazionale di scienze naturali della Cina (nn. 21573031 e 21373038), programma per talenti eccellenti nella città di Dalian (2016RD09) e Istituto tecnologico e alta formazione di Hong Kong (THEi SG1617105 e THEi SG1617127).

Attenzione: Per la corretta manipolazione metodi, proprietà e tossicità dei prodotti chimici descritti in questa carta, fare riferimento alle schede di dati di sicurezza materiale (MSDS). Alcune delle sostanze chimiche utilizzate sono tossici e cancerogene e speciali cure devono essere prese. Nanomateriali potenzialmente possono rappresentare rischi per la sicurezza e gli effetti sulla salute. Inalazione e contatto dovrebbe essere evitato. Precauzione di sicurezza deve essere esercitato, ad esempio eseguendo la sintesi catalizzatore nella valutazione fume hood e catalizzatore delle prestazioni con reattori di autoclave. Dispositivi di protezione individuale devono essere indossati.
1. preparazione del Ni0,97Nb0.03catalizzatori O dove i rapporti molari Nb:(Ni+Nb) pari a 0,03
<ol><li>0,161 g di idrato di ossalato di niobio (V) si combinano con 2,821 g di nitrato di nichel in 100 mL di acqua deionizzata in un pallone da 250 mL a collo tre fondo tondo dotata di una barra per l'agitazione.</li>
	<li>Mescolare la soluzione a 50 rpm e 70 ° C per sciogliere i composti fino alla scomparsa del precipitato con un riscaldamento agitatore magnetico.</li>
	<li>Aumentare la temperatura rapidamente a 80 ° C a una velocità di 2 ° C/min.</li>
	<li>Aggiungere goccia a goccia una soluzione mista di base [acquosa di idrossido di ammonio (50 mL, 1.0 M) e idrossido di sodio (50 mL, 0,2 M)] nella miscela di reazione fino a quando il pH della soluzione Ni/Nb raggiunge 9.0.</li>
	<li>Agitando la miscela di reazione, alzare la temperatura fino a 120 ° C a 2 ° C/min.</li>
	<li>Mescolare la miscela di reazione durante la notte a 50 giri/min a 120 ° C fino alla completa scomparsa del colore verde della soluzione.</li>
	<li>Eseguire emissione ottica al plasma accoppiato induttivamente (ICP-OES) spettrometria per la soluzione valutare la concentrazione di Ni rimanenti2 + e Nb5 + ioni nella soluzione e garantire la completa precipitazione di nichel rimanenti nitrato.</li>
	<li>Raccogliere il solido mediante filtrazione utilizzando beuta Büchner. Lavare il solido aggiungendo acqua 2L deionizzata ripetutamente entro 20 min per rimuovere il residuo catione Na+ .</li>
	<li>Raccogliere il solido in un vetro da orologio. Asciugare il solido a 110 ° C per 12 h in forno secco.</li>
	<li>Calcine riscaldando i solidi in aria sintetica (20 mL/min O2 e 80 mL/min N2) a 450 ° C per 5 h in forno tubolare. Controllare tutta la cristalleria per difetto prima dell'uso l'alta temperatura di reazione.</li>
	<li>Dopo la calcinazione, ottenere 1 g di Ni0,97catalizzatore0,03O Nb. Utilizzare adeguati dispositivi di protezione come occhiali di sicurezza, guanti, camice da laboratorio e cappa aspirante per eseguire la reazione di nanocristallo a causa di potenziali rischi per la sicurezza e la salute dei nanomateriali.</li>
</ol>2. preparazione del Ni0.92Nb0,08O catalizzatori dove rapporti molari Nb:(Ni+Nb) pari a 0,08.
<ol><li>Questa procedura è simile a quella di 1 tranne che per i primi due passaggi:<ol>
<li>Sciogliere 0,43 g di idrato di ossalato di niobio (V) in 100 mL di acqua deionizzata.</li>
		<li>Separatamente, sciogliere 2,675 g di nitrato di nichel in 100 mL di acqua deionizzata.</li>
	</ol>
</li>
</ol>3. preparazione di Ni0,85Nb0.15catalizzatori O dove i rapporti molari Nb:(Ni+Nb) pari a 0,15
<ol><li>La procedura è simile a quella di 1 tranne che per i primi due passaggi:<ol>
<li>Sciogliere 0,807 g di idrato di ossalato di niobio (V) in 100 mL di acqua deionizzata.</li>
		<li>Separatamente, sciogliere 2,472 g di nitrato di nichel in 100 mL di acqua deionizzata.</li>
	</ol>
</li>
</ol>4. preparazione di Ni0.80Nb0,20O catalizzatori dove rapporti molari Nb:(Ni+Nb) pari a 0.20
<ol><li>La procedura è simile a quella di 1 tranne che per i primi due passaggi:<ol>
<li>Sciogliere 1,076 g di idrato di ossalato di niobio (V) in 100 mL di acqua deionizzata.</li>
		<li>Separatamente, sciogliere 2,326 g di nitrato di nichel in 100 mL di acqua deionizzata.</li>
	</ol>
</li>
</ol>5. preparazione di Nb2O5 utilizzando il metodo di precipitazione chimica
<ol><li>Calcine acido niobic (Nb2O5·nH2O) in aria sintetica per 5h a 450 ° C per ottenere puro Nb2O5 particelle. Nota: Confermare il completamento della reazione usando analisi di diffrazione (XRD) di polvere dei raggi x, dove Nb2O5·nH2O è amorfa e Nb2O5 è cristallina. Secondo l'analisi, la calcinazione per 5h a 450 ° C è stato sufficiente per completare la reazione.</li>
</ol>6. sintesi di lignina β-O-4 modello composto, 2-(2-methoxyphenoxy)-1-phenylethan-1-one
<ol><li>Sciogliere bromoacetophenone (9,0 g, 45 mmol) e 2-metossifenolo (6,6 g, 53 mmol) in 200 mL di dimetilformammide (DMF) in una beuta da 500 mL con un agitatore magnetico. Utilizzare appropriato cappuccio protettivo dei fumi e di apparecchiature per eseguire la reazione utilizzando reagenti e prodotti chimici corrosivi e cancerogeni.</li>
	<li>Miscelare la soluzione DMF sopra con idrossido di potassio (3,0 g, 53 mmol) e mescolare il composto durante la notte a 50 giri/min a temperatura ambiente utilizzando agitatori magnetici.</li>
	<li>Estrarre il prodotto con la soluzione di miscela di 200 mL di H2O e 600 mL di etere etilico (1:3, v/v) usando l'imbuto separatore. Ottenere lo strato di etere etilico superiore della soluzione.</li>
	<li>Aggiungere MgSO4 (10 g) per assorbire l'umidità della soluzione di etere etilico. Filtrare il MgSO4 per ottenere la soluzione di etere etilico utilizzando carta da filtro e imbuto.</li>
	<li>Dopo la rimozione della soluzione di etere etilico sotto pressione ridotta a 0,08 MPa mediante evaporatore rotante, disciogliere il residuo in 5 mL di etanolo.</li>
	<li>Evaporare il solvente di etanolo per ricristallizzare il prodotto in un becher da 10 mL. Ottenere il prodotto (11,5 g) come polvere giallastra e la resa del prodotto è basato su bromoacetophenone il 90%. Da 1analisi H NMR, 1H NMR (DMSO): δ 3.78 (s, 3 H, OCH3), 5,54 (s, 2 H, CH2), ppm 6,82-8.01 (m, H 9, aromatico). 17
</li>
</ol>7. Hydrodeoxygenation di lignina-derivati aromatici Ether
Nota: L'etere di aromatica selezionata lignina-derivato è anisolo in questo esperimento e il catalizzatore è Ni0.92Nb0,08adeguati dispositivi di protezione O. uso e cappa per eseguire la reazione utilizzando reagenti cancerogeni.
<ol><li>Equipaggiare un reattore autoclave di acciaio inox da 50 mL con una stufa e un agitatore magnetico.</li>
	<li>Ridurre il Ni0.92catalizzatore di0,08O Nb (1 g) ottenuto dal passaggio 2 nel reattore autoclave in atmosfera di2 H a 400 ° C per 2 h e quindi passivare il catalizzatore sotto Argon (50 mL/min) durante la notte.</li>
	<li>Sciogliere anisolo (g 1,1712, 8% in peso) in n-decano (20 mL) con l'uso di n-dodecano (0,2928 g, 2% in peso) come standard interno per l'analisi quantitativa gas cromatografia (GC).</li>
	<li>Introdurre i catalizzatori ridotti (0,1 g) nel reattore autoclave rapidamente per evitare il tempo di esposizione lungo con aria (< 5 minuti).</li>
	<li>Sigillare il reattore autoclave, purge con H2 più volte (3 volte, a 3 MPa pressione) per eliminare aria e quindi la miscela di reazione alla pressione dell'atmosfera.</li>
	<li>Impostare la velocità di agitazione a 700 rpm.</li>
	<li>Dopo il riscaldamento alla temperatura desiderata a 160-210 ° C a 2 ° C/min, pressurizzare il reattore autoclave a 3 MPa e impostare il punto di zero-tempo (t = 0). Nota: La gamma di temperatura di 160-210 ° C è opportuno in questo rapporto.</li>
	<li>Successivamente, raffreddare immediatamente la miscela a temperatura ambiente compresa tra 10 ° C/min e analizzare i prodotti deossigenati mediante gascromatografia con rivelatore di massa selettivo. 17
</li>
	<li>Determinare la conversione del modello di lignina composto secondo la seguente equazione: <img alt="Equation 1" src="/files/ftp_upload/56987/56987eq1.jpg">
</li>
	<li>Determinare la selettività di prodotto secondo la seguente equazione: <img alt="Equation 2" src="/files/ftp_upload/56987/56987eq2.jpg">
</li>
</ol>

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Non abbiamo nulla di divulgare.

Uno dei metodi comuni per preparare le nanoparticelle di ossido di niobio nichel-drogato alla rinfusa è metodo di evaporazione rotante. 9 impiegando varie condizioni di pressione e temperatura durante il processo di evaporazione rotativa, la precipitazione del commercio di particelle Ni-Nb-O con la lenta rimozione del solvente. In contrasto con il metodo di evaporazione rotativa, il metodo di precipitazione chimica riferito in questo studio ha ricevuto crescente attenzione per preparare le nanopa...

La preparazione dei nanocompositi ha ricevuto l'attenzione aumentante dovuto la loro applicazione cruciale in vari campi. Per preparare nanoparticelle di ossido di Ni-Nb-O miscelato,1,2,3,4,5,6 diversi metodi sono stati sviluppati come metodo di miscelazione a secco,7, metodo di evaporazione di 8 ,9,10,11,12,13 sol gel metodo, metodo di decomposizione termica di14 ,15 e auto-combustione. 16 in un tipico evaporazione metodo9, soluzioni acquose contenenti la giusta quantità di precursori metallo, nichel nitrato esaidrato e ammonio ossalato di niobio sono stati riscaldati a 70 ° C. Dopo la rimozione del solvente e ulteriore essiccazione e calcinazione, l'ossido misto è stata ottenuta. Questi catalizzatori di ossido mostrano eccellente attività catalitica e selettività verso la deidrogenazione ossidativa (ODH) di etano, imparentato con il riarrangiamento di elettronico e strutturale indotto dall'incorporazione di cationi di niobio nel reticolo NiO . 11 l'inserimento di Nb diminuisce drasticamente le specie elettrofile dell'ossigeno, che è responsabile per le reazioni di ossidazione di etano12. Di conseguenza, le estensioni di questo metodo sono state fatte sulla preparazione di diversi tipi di ossidi misti di Ni-Me-O, dove mi = Li, Mg, Al, Ga, Ti e Ta. 13 si trova che la variazione di droganti metallo potrebbe alterare i radicali dell'ossigeno non selettiva ed elettrofila di NiO, così sistematicamente sintonizzare l'ODH attività e selettività nei confronti di etano. Tuttavia, generalmente la superficie di questi ossidi è relativamente piccolo (< 100 m2/g), a causa della segregazione di fase estesa e la formazione di grandi cristalliti Nb2O5 e così ostacolato loro usi in altri catalitica applicazioni.
Secco di miscelazione metodo, noto anche come il metodo di rettifica a stato solido, è un altro metodo comunemente usato per preparare i catalizzatori di ossidi misti. Poiché i materiali catalitici sono ottenuti in modo privo di solventi, questo metodo fornisce una promettente alternativa verde e sostenibile per la preparazione di ossidi misti. La più alta superficie ottenuta con tale metodo è 172 m2/g per Ni80Nb20 temperatura calcinazione di 250 ° C. 8 tuttavia, questo metodo a stato solido non è affidabile come reagenti non sono ben miscelati su scala atomica. Di conseguenza, per un migliore controllo di omogeneità chimica e distribuzione granulometrica specifici e morfologia, altri metodi adatti per preparare Ni-Nb-O mescolato ossido nanoparticelle ancora stanno cercande. 7
Tra le varie strategie nello sviluppo delle nanoparticelle, precipitazione chimica serve come uno dei metodi promettenti per sviluppare la nanocatalisi, in quanto permette la completa precipitazione degli ioni del metallo. Inoltre, le nanoparticelle di aree di superficie superiore comunemente sono preparate utilizzando questo metodo. Per migliorare le proprietà catalitiche di Ni-Nb-O nanoparticelle, qui segnaliamo il protocollo per la sintesi di una serie di catalizzatori di ossido Ni-Nb-O mescolato con elevata superficie di metodo di precipitazione chimica. Abbiamo dimostrato che il rapporto molare di Nb:Ni è un fattore cruciale nel determinare l'attività catalitica degli ossidi verso il hydrodeoxygenation di composti organici derivati da lignina. Con rapporto di alta Nb:Ni sopra 0,087, inattivi specie NiNb2O6 sono stati formati. NI0.92Nb0,08O, che ha avuto la più grande area di superficie (173 m2/g), esposizioni nanosheets piega-come strutture e ha mostrato la migliore attività e selettività verso il hydrodeoxygenation di anisolo a cicloesano.

<table>
	<tbody>
		<tr>
			<td>Niobium(V) oxalate hydrate, 98%</td>
			<td>Alfa</td>
			<td>L04481902</td>
			<td></td>
		</tr>
		<tr>
			<td>Nickel nitrate hexahydrate, 99%</td>
			<td>Aladdin</td>
			<td>N108891</td>
			<td></td>
		</tr>
		<tr>
			<td>Sodium hydroxide, 98%</td>
			<td>Aladdin</td>
			<td>S111501</td>
			<td></td>
		</tr>
		<tr>
			<td>Ammonium hydroxide, 23-25%</td>
			<td>Aladdin</td>
			<td>A112077</td>
			<td></td>
		</tr>
		<tr>
			<td>Anisole, 99%</td>
			<td>Sinopharm</td>
			<td>81001728</td>
			<td></td>
		</tr>
		<tr>
			<td>Diphenyl ether, 98%</td>
			<td>Aladdin</td>
			<td>D110644</td>
			<td></td>
		</tr>
		<tr>
			<td>Phenol, 98%</td>
			<td>Sinopharm</td>
			<td>100153008</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Methoxyphenol, 98%</td>
			<td>Sinopharm</td>
			<td>30114526</td>
			<td></td>
		</tr>
		<tr>
			<td>Vanillin, 99.5%</td>
			<td>Sinopharm</td>
			<td>69024316</td>
			<td></td>
		</tr>
		<tr>
			<td>Potassium hydroxide, AR</td>
			<td>Aladdin</td>
			<td>P112284</td>
			<td></td>
		</tr>
		<tr>
			<td>N,N-Dimethylformamide, 99.5%</td>
			<td>Sinopharm</td>
			<td>40016462</td>
			<td></td>
		</tr>
		<tr>
			<td>2-Bromoacetophenone,98%</td>
			<td>Aladdin</td>
			<td>B103328</td>
			<td></td>
		</tr>
		<tr>
			<td>Diethyl ether,99.5%</td>
			<td>Sinopharm</td>
			<td>10009318</td>
			<td></td>
		</tr>
		<tr>
			<td>Decane,98%</td>
			<td>Aladdin</td>
			<td>D105231</td>
			<td></td>
		</tr>
		<tr>
			<td>Dodecane,99%</td>
			<td>Aladdin</td>
			<td>D119697</td>
			<td></td>
		</tr>
		<tr>
			<td>Niobic acid</td>
			<td>CBMM</td>
			<td>1313968</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating and Drying Oven</td>
			<td></td>
			<td></td>
			<td>DHG Series (shanghai jinghong laboratory instrument co. ltd)</td>
		</tr>
		<tr>
			<td>Autoclave Reactor</td>
			<td></td>
			<td></td>
			<td>CJF-0.05&#8212;0.1L (Dalian Tongda Equipment Technology Development Co., Ltd)</td>
		</tr>
		<tr>
			<td>Tube&#160;furnace</td>
			<td></td>
			<td></td>
			<td>SK2-1-10/12 (Luoyang Huaxulier Electric Stove Co., Ltd)</td>
		</tr>
		<tr>
			<td>Heating magnetic stirrer</td>
			<td></td>
			<td></td>
			<td>DF-101 (Yu Hua Instrument Co. Ltd.)</td>
		</tr>
		<tr>
			<td>Rotary evaporator</td>
			<td></td>
			<td></td>
			<td>RE-3000A (Shanghai Yarong Biochemical Instrument Factory)</td>
		</tr>
		<tr>
			<td>Synthetic air</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hydrogen gas</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Argon gas</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

chemical precipitation method for the synthesis of nb2o5 modified bulk nickel catalysts with high specific surface area

Dimostriamo un metodo per la sintesi di NixNb1-xO catalizzatori con nanostrutture spugnoso e piega-like. Variando il rapporto di Nb:Ni, una serie di NixNb1-xO nanoparticelle di varia composizione atomiche (x = 0,03, 0,08 e 0,15 0,20) sono state preparate da precipitazione chimica. Questi catalizzatori di1-xO NbxNi sono caratterizzati da diffrazione di raggi x, spettroscopia fotoelettronica a raggi x e microscopia elettronica. Lo studio ha rivelato l'aspetto spugnoso e piega-come di Ni0,97Nb0.03O e Ni0.92Nb0,08O sulla superficie NiO e la più grande superficie di questi catalizzatori di1-xO NixNb, confrontato con la maggior parte NiO. Superficie massima di 173 m2/g può essere ottenuta per catalizzatori O di Ni0.92Nb0,08. Inoltre, sono stati studiati gli idrotrattamento catalitico di lignina derivata composti utilizzando i sintetizzato Ni0.92Nb0,08O catalizzatori.

Modelli di diffrazione di raggi x (XRD) (Figura 1 e Figura 2), scommessa aree superficiali, temperatura programmata riduzione dell'idrogeno con l'idrogeno (H2- TPR), microscopia elettronica (SEM) equipaggiato con un energia-dispersiva dei raggi x (EDX ) analizzatore, spettroscopia fotoelettronica a raggi x (XPS) sono stati raccolti per le nanoparticelle NiO, Ni-Nb-O e Nb2O5 ossidi<sup class="xref"...

Watch this Scientific Journal Video about Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area at JoVE.com

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

Un protocollo per la sintesi di spugnoso e piega-come Ni1-xNbxO nanoparticelle di precipitazione chimica è presentato.

Modificare il metodo di precipitazione chimica per la sintesi di Nb2O5 catalizzatori di nichel Bulk con elevata superficie specifica

We demonstrate a method for the synthesis of NixNb1-xO catalysts with sponge-like and fold-like nanostructures. By varying the Nb:Ni ratio, a series of ...

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Research

JoVE Journal

Chemistry

Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

11.7K Views.  Dalian University of Technology. Un protocollo per la sintesi di spugnoso e piega-come Ni1-xNbxO nanoparticelle di precipitazione chimica è presentato.

Video: Chemical Precipitation Method for the Synthesis of Nb2O5 Modified Bulk Nickel Catalysts with High Specific Surface Area

Gyroid Nickel Nanostructures from Diblock Copolymer Supramolecules

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, have high porosity, high surface-to-volume and strength-to-weight ratio. Unfortunately, common approaches for preparation of metallic nanostructures render materials with highly disordered architecture, which might have an adverse effect on their mechanical properties. Block copolymers have the ability to self-assemble into ordered nanostructures and can be applied as templates for the preparation of well-ordered metal nanofoams. Here we describe the application of a block copolymer-based supramolecular complex - polystyrene-block-poly(4-vinylpyridine)(pentadecylphenol) PS-b-P4VP(PDP) - as a precursor for well-ordered nickel nanofoam. The supramolecular complexes exhibit a phase behavior similar to conventional block copolymers and can self-assemble into the bicontinuous gyroid morphology with two PS networks placed in a P4VP(PDP) matrix. PDP can be dissolved in ethanol leading to the formation of a porous structure that can be backfilled with metal. Using electroless plating technique, nickel can be inserted into the template&#39;s channels. Finally, the remaining polymer can be removed via pyrolysis from the polymer/inorganic nanohybrid resulting in nanoporous nickel foam with inverse gyroid morphology.

This article describes the preparation of well-ordered nickel nanofoams via electroless metal deposition onto nanoporous templates obtained from self-assembled diblock copolymer based supramolecules.

Gyroid Nickel Nanostrutture da diblock Copolimero supramolecole

Nanoporous metal foams possess a unique combination of properties - they are catalytically active, thermally and electrically conductive, and furthermore, ...

Ricerca

Chimica

A Method to Manipulate Surface Tension of a Liquid Metal via Surface Oxidation and Reduction

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where interfacial tension is a dominant force. A variety of methods exist for controlling the interfacial tension of aqueous and organic liquids on this scale; however, these techniques have limited utility for liquid metals due to their large interfacial tension.
Liquid metals can form soft, stretchable, and shape-reconfigurable components in electronic and electromagnetic devices. Although it is possible to manipulate these fluids via mechanical methods (e.g., pumping), electrical methods are easier to miniaturize, control, and implement. However, most electrical techniques have their own constraints: electrowetting-on-dielectric requires large (kV) potentials for modest actuation, electrocapillarity can affect relatively small changes in the interfacial tension, and continuous electrowetting is limited to plugs of the liquid metal in capillaries.
Here, we present a method for actuating gallium and gallium-based liquid metal alloys via an electrochemical surface reaction. Controlling the electrochemical potential on the surface of the liquid metal in electrolyte rapidly and reversibly changes the interfacial tension by over two orders of magnitude ( &#820;500 mN/m to near zero). Furthermore, this method requires only a very modest potential (&#60; 1 V) applied relative to a counter electrode. The resulting change in tension is due primarily to the electrochemical deposition of a surface oxide layer, which acts as a surfactant; removal of the oxide increases the interfacial tension, and vice versa. This technique can be applied in a wide variety of electrolytes and is independent of the substrate on which it rests.

We present a method to control the interfacial energy of a liquid metal in an electrolyte via electrochemical deposition (or removal) of a surface oxide layer. This simple method can control the capillary behavior of gallium-based liquid metals by tuning the interfacial energy rapidly, significantly, and reversibly using modest voltages.

Un metodo per manipolare Tensione superficiale di un metallo liquido tramite ossidazione superficiale e riduzione

Controlling interfacial tension is an effective method for manipulating the shape, position, and flow of fluids at sub-millimeter length scales, where ...

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of trifluoromethoxylated aromatic compounds remains a formidable challenge in organic synthesis. Conventional approaches often suffer from poor substrate scope, or require use of highly toxic, difficult-to-handle, and/or thermally labile reagents. Herein, we report a user-friendly protocol for the synthesis of methyl 4-acetamido-3-(trifluoromethoxy)benzoate using 1-trifluoromethyl-1,2-benziodoxol-3(1H)-one (Togni reagent II). Treating methyl 4-(N-hydroxyacetamido)benzoate (1a) with Togni reagent II in the presence of a catalytic amount of cesium carbonate (Cs2CO3) in chloroform at RT afforded methyl 4-(N-(trifluoromethoxy)acetamido)benzoate (2a). This intermediate was then converted to the final product methyl 4-acetamido-3-(trifluoromethoxy)benzoate (3a) in nitromethane at 120 &#176;C. This procedure is general and can be applied to the synthesis of a broad spectrum of ortho-trifluoromethoxylated aniline derivatives, which could serve as useful synthetic building blocks for the discovery and development of new pharmaceuticals, agrochemicals, and functional materials.

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives

An operationally simple procedure for the synthesis of ortho-trifluoromethoxylated aniline derivatives via a two-step sequence of O-trifluoromethylation of N-aryl-N-hydroxyacetamide followed by thermally induced intramolecular OCF3-migration is reported.

Protocollo per la sintesi di<em&gt; Ortho</em&gt; Derivati ​​all&#39;anilina -trifluoromethoxylated

Molecules bearing trifluoromethoxy (OCF3) group often show desired pharmacological and biological properties. However, facile synthesis of ...

Facile Synthesis of Worm-like Micelles by Visible Light Mediated Dispersion Polymerization Using Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins with the synthesis of a hydrophilic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA) homopolymer using reversible addition-fragmentation chain-transfer (RAFT) polymerization. Under mild visible light irradiation (&#955; = 460 nm, 0.7 mW/cm2), this macro-chain transfer agent (macro-CTA) in the presence of a ruthenium based photoredox catalyst, Ru(bpy)3Cl2 can be chain extended with a second monomer to form a well-defined block copolymer in a process known as Photoinduced Electron Transfer RAFT (PET-RAFT). When PET-RAFT is used to chain extend POEGMA with benzyl methacrylate (BzMA) in ethanol (EtOH), polymeric nanoparticles with different morphologies are formed in situ according to a polymerization-induced self-assembly (PISA) mechanism. Self-assembly into nanoparticles presenting POEGMA chains at the corona and poly(benzyl methacrylate) (PBzMA) chains in the core occurs in situ due to the growing insolubility of the PBzMA block in ethanol. Interestingly, the formation of highly pure worm-like micelles can be readily monitored by observing the onset of a highly viscous gel in situ due to nanoparticle entanglements occurring during the polymerization. This process thereby allows for a more reproducible synthesis of worm-like micelles simply by monitoring the solution viscosity during the course of the polymerization. In addition, the light stimulus can be intermittently applied in an ON/OFF manner demonstrating temporal control over the nanoparticle morphology.

This article describes a process for producing polymeric self-assembled nanoparticles using visible light mediated dispersion polymerization. Using low energy visible light to control the polymerization allows for the reproducible formation of self-assembled worm-like micelles at high solids content.

Sintesi facile di micelle vermiforme dalla luce visibile mediata polimerizzazione in dispersione Utilizzando Photoredox Catalyst

Presented herein is a protocol for the facile synthesis of worm-like micelles by visible light mediated dispersion polymerization. This approach begins ...

Synthesis and Testing of Supported Pt-Cu Solid Solution Nanoparticle Catalysts for Propane Dehydrogenation

A convenient method for the synthesis of bimetallic Pt-Cu catalysts and performance tests for propane dehydrogenation and characterization are demonstrated here. The catalyst forms a substitutional solid solution structure, with a small and uniform particle size around 2 nm. This is realized by careful control over the impregnation, calcination, and reduction steps during catalyst preparation and is identified by advanced in situ synchrotron techniques. The catalyst propane dehydrogenation performance continuously improves with increasing Cu:Pt atomic ratio.

A convenient method for the synthesis of 2 nm supported bimetallic nanoparticle Pt-Cu catalysts for propane dehydrogenation is reported here. In situ synchrotron X-ray techniques allow for the determination of the catalyst structure, which is typically unobtainable using laboratory instruments.

Sintesi e test di sostanza solida Pt-Cu sostenuta Catalizzatori di nanoparticelle per la deidrogenazione del propano

A convenient method for the synthesis of bimetallic Pt-Cu catalysts and performance tests for propane dehydrogenation and characterization are ...

Synthesis of Platinum-nickel Nanowires and Optimization for Oxygen Reduction Performance

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen reduction reaction. Spontaneous galvanic displacement was used to deposit Pt layers onto Ni nanowire substrates. The synthesis approach produced catalysts with high specific activities and high Pt surface areas. Hydrogen annealing improved Pt and Ni mixing and specific activity. Acid leaching was used to preferentially remove Ni near the nanowire surface, and oxygen annealing was used to stabilize near-surface Ni, improving durability and minimizing Ni dissolution. These protocols detail the optimization of each post-synthesis processing step, including hydrogen annealing to 250 &#176;C, exposure to 0.1 M nitric acid, and oxygen annealing to 175 &#176;C. Through these steps, Pt-Ni nanowires produced increased activities more than an order of magnitude than Pt nanoparticles, while offering significant durability improvements. The presented protocols are based on Pt-Ni systems in the development of fuel cell catalysts. These techniques have also been used for a variety of metal combinations, and can be applied to develop catalysts for a number of electrochemical processes.

&#160; The protocol describes the synthesis and electrochemical testing of platinum-nickel nanowires. Nanowires were synthesized by the galvanic displacement of a nickel nanowire template. Post-synthesis processing, including hydrogen annealing, acid leaching, and oxygen annealing were used to optimize nanowire performance and durability in the oxygen reduction reaction.

Sintesi di nanofili di platino-nichel e ottimizzazione per le prestazioni di riduzione di ossigeno

Platinum-nickel (Pt-Ni) nanowires were developed as fuel cell electrocatalysts, and were optimized for the performance and durability in the oxygen ...

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and porous metal-dithiolene network in the highly ordered single crystalline state. Unlike the highly reactive free-standing thiols, which tend to decompose and complicate the crystallization of metal-thiolate open frameworks, the thioester reacts in situ to provide the thiol species, serving to mitigate the reaction between the mercaptan units and the metal centers, and to improve crystallization consequently. Specifically, the thioester was synthesized in a one-pot procedure: an aromatic bromide (hexabromotriphenylene) reacted with excess sodium thiomethoxide under vigorous conditions to first form the thioether intermediate product. The thioether was then demethylated by the excess thiomethoxide to provide the thiolate anion that was acylated to form the thioester product. The thioester was conveniently purified by standard column chromatography, and then used directly in the framework synthesis, wherein NaOH and ethylenediamine serve to revert in situ the thioester to the thiol linker for assembling the single-crystalline Pb(II)-dithiolene network. Compared with other methods for thiol synthesis (e.g., by cleaving alkyl thioether using sodium metal and liquid ammonia), the thioester synthesis here uses simple conditions and economical reagents. Moreover, the thioester product is stable and can be conveniently handled and stored. More importantly, in contrast to the generic difficulty in accessing crystalline metal-thiolate open frameworks, we demonstrate that using the thioester for in situ formation of the thiol linker greatly improves the crystallinity of the solid-state product. We intend to encourage broader research efforts on the technologically important metal-sulfur frameworks by disclosing the synthetic protocol for the thioester as well as the crystalline framework solid.

Here, we present a one-pot, transition-metal-free synthesis of thiols and thioesters from aromatic halides and sodium thiomethoxide, followed by the preparation of single crystals of a metal-dithiolene network using thiol species generated in situ from the more stable and tractable thioester.

Sintesi di un tiolo Building Block per la cristallizzazione di un quadro di Gyroidal metallo-zolfo ossidi semiconduttori

We present a method for preparing thioester molecules as the masked form of the thiol linkers and their utilization for accessing a semiconducting and ...

Synthesis of Substrate-Bound Au Nanowires Via an Active Surface Growth Mechanism

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a challenge, as it requires asymmetric growth of symmetric crystals. Here, we report a distinctive synthesis of substrate-bound Au nanowires. This template-free synthesis employs thiolated ligands and substrate adsorption to achieve the continuous asymmetric deposition of Au in solution at ambient conditions. The thiolated ligand prevented the Au deposition on the exposed surface of the seeds, so the Au deposition only occurs at the interface between the Au seeds and the substrate. The side of the newly deposited Au nanowires is immediately covered with the thiolated ligand, while the bottom facing the substrate remains ligand-free and active for the next round of Au deposition. We further demonstrate that this Au nanowire growth can be induced on various substrates, and different thiolated ligands can be used to regulate the surface chemistry of the nanowires. The diameter of the nanowires can also be controlled with mixed ligands, in which another &#34;bad&#34; ligand could turn on the lateral growth. With the understanding of the mechanism, Au nanowire-based nanostructures can be designed and synthesized.

We report a solution-based method to synthesize substrate-bound Au nanowires. By tuning the molecular ligands used during the synthesis, the Au nanowires can be grown from various substrates with different surface properties. Au nanowire-based nanostructures can also be synthesized by adjusting the reaction parameters.

Sintesi di nanofili Au associato a substrato tramite un meccanismo di crescita superficiale attiva

Advancing synthetic capabilities is important for the development of nanoscience and nanotechnology. The synthesis of nanowires has always been a ...

Synthesis and Characterization of 1,2-Dithiolane Modified Self-Assembling Peptides

This report focuses on the synthesis of an N-terminus 1,2-dithiolane modified self-assembling peptide and the characterization of the resulting self-assembled supramolecular structures. The synthetic route takes advantage of solid-phase peptide synthesis with the on-resin coupling of the dithiolane precursor molecule, 3-(acetylthio)-2-(acetylthiomethyl)propanoic acid, and the microwave-assisted thioacetate deprotection of the peptide N-terminus before final cleavage from the resin to yield the 1,2-dithiolane modified peptide. After the high-performance liquid chromatography (HPLC) purification of the 1,2-dithiolane peptide, derived from the nucleating core of the A&#946; peptide associated with Alzheimer&#39;s disease, the peptide is shown to self-assemble into cross-&#946; amyloid fibers. Protocols to characterize the amyloid fibers by Fourier-transform infrared spectroscopy (FT-IR), circular dichroism spectroscopy (CD) and transmission electron microscopy (TEM) are presented. The methods of N-terminal modification with a 1,2-dithiolane moiety to well-characterized self-assembling peptides can now be explored as model systems to develop post-assembly modification strategies and explore dynamic covalent chemistry on supramolecular peptide nanofiber surfaces.

A protocol for the synthesis of a 1,2-dithiolane modified peptide and the characterization of the supramolecular structures resulting from the peptide self-assembly.

Sintesi e caratterizzazione di 1,2-Dithiolane per volta peptidi autoassemblanti

This report focuses on the synthesis of an N-terminus 1,2-dithiolane modified self-assembling peptide and the characterization of the resulting ...

Synthesis and Bioconjugation of Thiol-Reactive Reagents for the Creation of Site-Selectively Modified Immunoconjugates

Maleimide-bearing bifunctional probes have been employed for decades for the site-selective modification of thiols in biomolecules, especially antibodies. Yet maleimide-based conjugates display limited stability in vivo because the succinimidyl thioether linkage can undergo a retro-Michael reaction. This, of course, can lead to the release of the radioactive payload or its exchange with thiol-bearing biomolecules in circulation. Both of these processes can produce elevated activity concentrations in healthy organs as well as decreased activity concentrations in target tissues, resulting in reduced imaging contrast and lower therapeutic ratios. In 2018, we reported the creation of a modular, stable, and easily accessible phenyloxadiazolyl methyl sulfone reagent &#8212; dubbed &#8216;PODS&#8217; &#8212; as a platform for thiol-based bioconjugations. We have clearly demonstrated that PODS-based site-selective bioconjugations reproducibly and robustly create homogenous, well-defined, highly immunoreactive, and highly stable radioimmunoconjugates. Furthermore, preclinical experiments in murine models of colorectal cancer have shown that these site-selectively labeled radioimmunoconjugates exhibit far superior in vivo performance compared to radiolabeled antibodies synthesized via maleimide-based conjugations. In this protocol, we will describe the four-step synthesis of PODS, the creation of a bifunctional PODS-bearing variant of the ubiquitous chelator DOTA (PODS-DOTA), and the conjugation of PODS-DOTA to the HER2-targeting antibody trastuzumab.

In this protocol, we will describe the synthesis of PODS, a phenyoxadiazolyl methyl sulfone-based reagent for the site-selective attachment of cargos to the thiols of biomolecules, particularly antibodies. In addition, we will describe the synthesis and characterization of a PODS-bearing bifunctional chelator and its conjugation to a model antibody.

Sintesi e Bioconjugation di tiolo-reattive reagenti per la creazione del sito-selettivamente per volta efattori

Maleimide-bearing bifunctional probes have been employed for decades for the site-selective modification of thiols in biomolecules, especially antibodies. ...

Modificare il metodo di precipitazione chimica per la sintesi di Nb₂O₅ catalizzatori di nichel Bulk con elevata superficie specifica

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