Name: millifluidics for chemical synthesis and time-resolved mechanistic studies
Uploaded: 2013-11-27T20:00:00
Description: Watch this Scientific Journal Video about Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies at JoVE.com

This research work is supported as part of the Center for Atomic Level Catalyst Design, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001058 and also supported by Board of Regents under grants award number LEQSF (2009-14)-EFRC-MATCH and LEDSF-EPS(2012)-OPT-IN-15. MRCAT operations are supported by the Department of Energy and the MRCAT member institutions. The use of the Advanced Photon Source at ANL is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. Financial support for JTM was provided as part of the Institute for Atom-efficient Chemical Transformations (IACT), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences.

Millifluidics set-up: Purchase a millifluidic chip (made of polyester terephthalate polymer) from Microplumbers Microsciences LLC, which has serpentine channels with dimensions of 2 mm (W) x 0.15 mm (H) x 220 mm (L). Use FEP Tubing &#160;with dimensions of 0.25 mm I.D., 1/16 in&#160;O.D., for connecting the chip to the pump. Use two different pumps for the two different experiments. Use P-Pump&#160;for the first experiment (copper nanoparticles) and the millifluidic device&#160;for the second experiment ...

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The UCNCs were formed by the reduction reaction of copper nitrate with sodium borohydride in the presence of the polymeric capping agent O-[2-(3-Mercaptopropionylamino)ethyl]-O&#39;-methylpolyethylene glycol (MW=5,000) [MPEG]. The reaction was performed within the millifluidic chip reactor at different flow-rates such as 6.8 ml/hr, 14.3 ml/hr, 32.7 ml/hr, and 51.4 ml/hr to study the effect of flow-rates on the UCNCs formed. The respective residence times for the above flow-rates are 47.49, 24.44, 16.56, and 9.02 sec. The...

Lab-on-a-chip (LOC) devices for chemical synthesis have demonstrated significant advantage in terms of increased mass and heat transfer, superior reaction control, high throughput and safer operation environment1. These devices can be broadly classified into chip based fluidics and nonchip based fluidic devices. Among the chip-based fluidics, microfluidics is well investigated and a topic well-covered in the literature2-5. Nonchip based LOC systems use tubular reactors6. Conventionally, microfluidic systems are used for precise control and manipulation of fluids that are geometrically constrained to submillimeter scale. We have recently introduced the concept of chip-based millifluidics, which can be used for manipulation of fluids in channels in millimeter scale (either width or depth or both of the channels are at least a millimeter in size)7-9. Furthermore, the millifluidic chips are relatively easy to fabricate while offering similar control over flow-rates and manipulation of reagents. These chips could also be operated at higher flow-rates, creating smaller residence times, thereby, offering the possibility for scale-up of controlled synthesis of nanoparticles with narrower size distribution. As an example, we have recently demonstrated the synthesis of ultra-small copper nanoclusters and characterized them using in situ X-ray absorption spectroscopy as well as TEM. Ability to obtain small residence times within millifluidic channels in combination with the use of MPEG, which is very efficient bidentate PEGylated stabilizing agent for the formation of stable colloids of copper nanoclusters7 .
In addition to the synthesis of chemicals and nanomaterials, the millifluidics could offer, due to higher volume and concentration at the probe area, a synthetic platform that is more generalized and efficient for time-resolved kinetic studies and also achieves better signal to noise ratio than microfluidic systems7,10. We show the use of millifluidic chip as an example for time resolved analysis of the growth of gold nanostructures from solution using in situ XAS with a time resolution as small as 5 msec11.
Also, majority of the micro reactors developed to date for catalysis applications are based on silicon12,13. Their expensive fabrication in addition to small volumes generated makes them unsuitable for large scale manufacturing. The two general methods for coating the channels with nanocatalysts - chemical and physical, often referred to as silicon coating procedures, are currently in vogue14,15 . In addition to expensive micro fabrication, clogging of the channels makes micro reactor catalysis may be unsuitable for large-scale manufacturing. Although microreactors have been used for heterogeneous catalysis in micro continuous flow-through processes earlier16-18 , the ability to control the dimension, and morphology of the embedded gold nanostructured catalysts within continuous flow channels was never explored before. We have recently developed a technology for coating the millifluidic channels with Au catalysts, having controlled nano morphology and dimensions (Figure 5)11, for carrying out catalysis of industrially important chemical reactions. As an example we have demonstrated conversion of 4-nitrophenol into 4-aminophenol catalyzed by nanostructured gold coated within the millifluidic channels. Considering that a single millifluidic reactor chip can produce flow-rates of 50-60 ml/hr,7 high-throughput and controlled synthesis of chemicals is possible either through continuous flow operation or parallel processing.
In order to capitalize on the possibilities the millifluidics offer, with few examples described as above, we also demonstrate a user-friendly millifluidic device that is portable and has the all the required components such as millifluidic chips, manifolds, flow controllers, pumps and electrical connections integrated. Such a millifluidic device, as shown in the Figure 7, is now available from the company Millifluidica LLC (<a href="http://www.millifluidica.com" target="_blank">www.millifluidica.com</a>). The manuscript also provides protocols using the hand-held millifluidic device, as described below, for controlled synthesis of nanomaterials, time-resolved analysis of reaction mechanisms and continuous flow catalysis.

<table border="1">
	<tbody>
		<tr>
			<td>Copper (II) nitrate hydrate</td>
			<td>Sigma-Aldrich</td>
			<td>13778-31-9</td>
			<td>99.999% pure</td>
		</tr>
		<tr>
			<td>O-[2-(3-mercaptopropionylamino)ethyl]-O&#8242;-methylpolyethylene glycol</td>
			<td>Sigma-Aldrich</td>
			<td>401916-61-8&#160;</td>
			<td>MW=5,000</td>
		</tr>
		<tr>
			<td>HAuCl4.3H2O (Chloroauric acid)</td>
			<td>Sigma-Aldrich</td>
			<td>27988-77-8&#160;</td>
			<td>99.999% pure</td>
		</tr>
		<tr>
			<td>meso-2,3-dimercaptosuccinic acid (DMSA)</td>
			<td>Sigma-Aldrich</td>
			<td>304-55-2</td>
			<td>~98% pure</td>
		</tr>
		<tr>
			<td>4-Nitrophenol</td>
			<td>Sigma-Aldrich</td>
			<td>100-02-7&#160;</td>
			<td>spectrophotometric grade</td>
		</tr>
		<tr>
			<td>4-Aminophenol</td>
			<td>Sigma-Aldrich</td>
			<td>123-30-8&#160;</td>
			<td>&#62;99% pure (HPLC grade)</td>
		</tr>
		<tr>
			<td>Sodium borohydride</td>
			<td>Sigma-Aldrich</td>
			<td>16940-66-2&#160;</td>
			<td>98% pure</td>
		</tr>
		<tr>
			<td>Sodium hydroxide pellets</td>
			<td>Sigma-Aldrich</td>
			<td>1310-73-2&#160;</td>
			<td>99.99% pure</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>[header]</td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>EQUIPMENT</td>
		</tr>
		<tr>
			<td>Millifluidic Chips</td>
			<td>Microplumbers Microsciences LLC</td>
			<td>SDC-01</td>
			<td>Made from polyester terephthalate polymer</td>
		</tr>
		<tr>
			<td>Pressure Pump</td>
			<td>Mitos P-Pump, Dolomite</td>
			<td>3200016</td>
			<td></td>
		</tr>
		<tr>
			<td>Automated Syringe Pump</td>
			<td>Cetoni Automation and Microsystems, GmbH</td>
			<td></td>
			<td>Syringe pump neMESYS</td>
		</tr>
		<tr>
			<td>UV-3600 UV-VIS-NIR Spectrophotometer</td>
			<td>Shimadzu</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Hand-held Millifluidic Device</td>
			<td>Millifluidica</td>
			<td>SCMD-1008</td>
			<td>Figure 7</td>
		</tr>
	</tbody>
</table>

millifluidics for chemical synthesis and time-resolved mechanistic studies

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the first, synthesis of ultra-small copper nanoclusters is described. The second example provides their utility for investigating time resolved kinetics of chemical reactions by analyzing gold nanoparticle formation using in situ X-ray absorption spectroscopy. The final example demonstrates continuous flow catalysis of reactions inside millifluidic channel coated with nanostructured catalyst.

Well dispersed and uniform sized copper nanoclusters with a narrow size distribution were obtained using the millifluidic chip setup (Fig. 1a). The different flow-rates used for synthesis did not have a significant effect on the size of the clusters. Nevertheless, with increase in the flow-rate, there is an observable improvement in the narrowing of the size distribution. UCNCs with a best narrow size distribution were obtained at a flow-rate of 32.7 mL/hr. The size of UCNCs formed at 32.7 mL/hr flow-rate has an average ...

Watch this Scientific Journal Video about Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies at JoVE.com

Millifluidics for Chemical Synthesis and Time-resolved Mechanistic Studies

Millifluidic devices are utilized for controlled synthesis of nanomaterials, time-resolved analysis of reaction mechanisms and continuous flow catalysis.

Procedures utilizing millifluidic devices for chemical synthesis and time-resolved mechanistic studies are described by taking three examples. In the ...

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