We thank the H.O.G. group at Arizona State University for developing the initial methodology of these hydrothermal experiments, and in particular, we thank I. Gould, E. Shock, L. Williams, C. Glein, H. Hartnett, K. Fecteau, K. Robinson, and C. Bockisch, for their guidance and helpful assistance. Z. Yang and X. Fu were funded by startup funds from Oakland University to Z. Yang.

1. Prepare the Sample for Hydrothermal Experiment
<ol>
	<li>Choose the size of the quartz or silica glass tubes, e.g., 2 mm inner diameter (ID) x 6 mm outer diameter (OD) or 6 mm ID x 12 mm OD, and determine the amounts of organic compounds and minerals to use. In this work, the amounts of nitrobenzene and magnetite (Fe3O4) to load into the silica tube (e.g., 2 mm ID x 6 mm OD) are 3.0 &#181;L and 13.9 mg, respectively. 
	NOTE: The large diameter tubes allow easier loading o...

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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=Microbial+diversity+in+the+deep+sea+and+the+underexplored+"rare+biosphere".">Microbial diversity in the deep sea and the underexplored "rare biosphere".</a> Proceedings of the National Academy of Sciences. 103 (32), 12115 (2006).</li><li>McCollom, T. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laboratory+Simulations+of+Abiotic+Hydrocarbon+Formation+in+Earth's+Deep+Subsurface.">Laboratory Simulations of Abiotic Hydrocarbon Formation in Earth's Deep Subsurface.</a> Reviews in Mineralogy and Geochemistry. 75 (1), 467-494 (2013).</li><li>Foustoukos, D. I., Seyfried, W. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hydrocarbons+in+Hydrothermal+Vent+Fluids:+The+Role+of+Chromium-Bearing+Catalysts.">Hydrocarbons in Hydrothermal Vent Fluids: The Role of Chromium-Bearing Catalysts.</a> Science. 304 (5673), 1002 (2004).</li><li>Bell, J. L. S., Palmer, D. A., Pittman, E. D., Lewan, M. D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=10.1007/978-3-642-78356-2_9.">10.1007/978-3-642-78356-2_9.</a> Organic Acids in Geological Processes. , 226-269 (1994).</li><li>Palmer, D. A., Drummond, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+decarboxylation+of+acetate.+Part+I.+The+kinetics+and+mechanism+of+reaction+in+aqueous+solution.">Thermal decarboxylation of acetate. Part I. The kinetics and mechanism of reaction in aqueous solution.</a> Geochimica et Cosmochimica Acta. 50 (5), 813-823 (1986).</li><li>Yang, Z., Gould, I. R., Williams, L. B., Hartnett, H. E., Shock, E. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+central+role+of+ketones+in+reversible+and+irreversible+hydrothermal+organic+functional+group+transformations.">The central role of ketones in reversible and irreversible hydrothermal organic functional group transformations.</a> Geochimica et Cosmochimica Acta. 98, 48-65 (2012).</li><li>McCollom, T. M., Ritter, G., Simoneit, B. R. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Lipid+Synthesis+Under+Hydrothermal+Conditions+by+Fischer-+Tropsch-Type+Reactions.">Lipid Synthesis Under Hydrothermal Conditions by Fischer- Tropsch-Type Reactions.</a> Origins of life and evolution of the biosphere. 29 (2), 153-166 (1999).</li><li>Bell, J. L. S., Palmer, D. A., Barnes, H. L., Drummond, S. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Thermal+decomposition+of+acetate:+III.+Catalysis+by+mineral+surfaces.">Thermal decomposition of acetate: III. Catalysis by mineral surfaces.</a> Geochimica et Cosmochimica Acta. 58 (19), 4155-4177 (1994).</li><li>Yang, Z., 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=Hydrothermal+Photochemistry+as+a+Mechanistic+Tool+in+Organic+Geochemistry:+The+Chemistry+of+Dibenzyl+Ketone.">Hydrothermal Photochemistry as a Mechanistic Tool in Organic Geochemistry: The Chemistry of Dibenzyl Ketone.</a> The Journal of Organic Chemistry. 79 (17), 7861-7871 (2014).</li><li>Yang, Z., Hartnett, H. E., Shock, E. L., Gould, I. 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K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Peptide+Synthesis+in+Early+Earth+Hydrothermal+Systems.">Peptide Synthesis in Early Earth Hydrothermal Systems.</a> Astrobiology. 9 (2), 141-146 (2009).</li><li>Byrappa, K., Yoshimura, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Handbook of Hydrothermal Technology. , (2001).</li><li>Johnson, J. W., Oelkers, E. H., Helgeson, H. 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In this study, we used nitrobenzene with mineral magnetite as an example to demonstrate how to evaluate mineral effects on hydrothermal organic reactions. Although the experiments are carried out in small silica glass tubes, highly reproducible results are observed in the magnetite experiments, i.e., 30.3 &#177; 1.4% in nitrobenzene conversion, which suggests the effectiveness and the reliability of this hydrothermal protocol. In the no-mineral experiments, the conversion of nitrobenzene is 5.2 &#177; 2.1%, whic...

Hydrothermal environments (i.e., aqueous media at elevated temperatures and pressures) are ubiquitous on Earth. The hydrothermal chemistry of organic compounds plays an essential role in a wide range of geochemical settings, such as organic sedimentary basins, petroleum reservoirs, and the deep biosphere1,2,3. Organic carbon transformations in hydrothermal systems occur not only in pure aqueous medium but also with dissolved or solid inorganic materials, such as Earth-abundant minerals. Minerals have been found to dramatically and selectively influence the hydrothermal reactivity of various organic compounds,1,4,5 but how to identify the mineral effects in complex hydrothermal systems still remains as a challenge. The goal of this study is to provide a relatively simple experimental protocol for studying mineral effects on hydrothermal organic reactions.
The laboratory studies of hydrothermal reactions traditionally use robust reactors that are made of gold, titanium, or stainless steel6,7,8,9. For example, gold bags or capsules have been favorably used, because gold is flexible, and it allows the sample pressure to be controlled by pressurizing water externally, which avoids generating a vapor phase inside the sample. However, these reactors are expensive and could be associated with potential metal catalytic effects10. Hence, it is imperative to find an alternative method with low cost but high reliability for these hydrothermal experiments.
In recent years, reaction tubes made of quartz or fused silica glass have been more frequently applied to hydrothermal experiments11,12,13. Compared to precious gold or titanium, quartz or silica glass is considerably cheaper but also the strong material. More importantly, quartz tubes have shown little catalytic effects and can be as inert as gold for the hydrothermal reactions11,14. In this protocol, we describe a general method for conducting small-scale hydrothermal organic-mineral experiments in thick-walled silica tubes. We present an example experiment using a model compound (i.e., nitrobenzene) in the presence/absence of an iron-oxide mineral (i.e., magnetite) in a 150 &#176;C hydrothermal solution, in order to show the mineral effect, as well as to demonstrate the effectiveness of this method.

<table>
	<tbody>
		<tr>
			<td>Chemicals:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dichloromethane</td>
			<td>VWR</td>
			<td>BDH23373.400</td>
			<td></td>
		</tr>
		<tr>
			<td>Dodecane</td>
			<td>Sigma-Aldrich</td>
			<td>297879</td>
			<td></td>
		</tr>
		<tr>
			<td>Nitrobenzene</td>
			<td>Sigma-Aldrich</td>
			<td>252379</td>
			<td></td>
		</tr>
		<tr>
			<td>Fe2O3</td>
			<td>Sigma-Aldrich</td>
			<td>310050</td>
			<td></td>
		</tr>
		<tr>
			<td>Fe3O4</td>
			<td>Sigma-Aldrich</td>
			<td>637106</td>
			<td></td>
		</tr>
		<tr>
			<td>Supplies:</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Silica tube</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum pump</td>
			<td>WELCH</td>
			<td>2546B-01</td>
			<td></td>
		</tr>
		<tr>
			<td>Vacuum line</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Oven</td>
			<td>Hewlett Packard</td>
			<td>5890</td>
			<td></td>
		</tr>
		<tr>
			<td>Thermocouple</td>
			<td>BENETECH</td>
			<td>GM1312</td>
			<td></td>
		</tr>
		<tr>
			<td>Gas chromatography</td>
			<td>Agilent</td>
			<td>7820A</td>
			<td></td>
		</tr>
	</tbody>
</table>

an experimental protocol for studying mineral effects on organic hydrothermal transformations

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the deep ocean. Roles of minerals are critical in many hydrothermal organic geochemical processes. Traditional hydrothermal methodology, which includes using reactors made of gold, titanium, platinum, or stainless-steel, is usually associated with the high cost or undesired metal catalytic effects. Recently, there is a growing tendency for using the cost-effective and inert quartz or fused silica glass tubes in hydrothermal experiments. Here, we provide a protocol for carrying out organic-mineral hydrothermal experiments in silica tubes, and we describe the essential steps in the sample preparation, experimental setup, products separation, and quantitative analysis. We also demonstrate an experiment using a model organic compound, nitrobenzene, to show the effect of an iron-containing mineral, magnetite, on its degradation under a specific hydrothermal condition. This technique can be applied to study complex organic-mineral hydrothermal interactions in a relatively simple laboratory system.

To demonstrate how to use this approach to study hydrothermal organic-mineral interactions, a simple experiment using a model compound, nitrobenzene, was conducted with mineral magnetite (Fe3O4) at a hydrothermal condition of 150 &#176;C and 5 bars for 2 h. To show the mineral effect, an experiment of nitrobenzene without mineral was also performed under the same hydrothermal condition. As shown in Figure 1a, two silica tubes were made f...

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An Experimental Protocol for Studying Mineral Effects on Organic Hydrothermal Transformations

Earth-abundant minerals play important roles in the natural hydrothermal systems. Here, we describe a reliable and cost-effective method for the experimental investigation of organic-mineral interactions under hydrothermal conditions.

Organic-mineral interactions are widely occurring in hydrothermal environments, such as hot springs, geysers on land, and the hydrothermal vents in the ...

This method can help answer key questions in the organic chemistry field such as how earth abundant minerals influence organic molecules in deep ocean hydrothermal systems. The main advantage of this technique is that it is low cost, easy to use, and reliable. Though this method can provide insight into organic mineral interactions in natural hydrothermal systems, it can also be applied to other areas such as hydrothermal treatment of organic glutens or biofused hydrothermal synthesis in green chemistry.Demonstrating the procedure will be Dr.Xuan Fu from my lab. To begin this procedure, choose a tube size and material and determine the amounts of organic compounds and minerals to use, as outlined in the text protocol. This demonstration will be carried out using nitrobenzene and magnetite loaded into a silicon tube with an inner diameter of two millimeters and an outer diameter of six millimeters.Using a tube cutter, cut the tubing into small pieces about 30 centimeters in length. Then, use an oxyhydrogen torch with an appropriate flame head to seal one end of the tube closed. If any of the starting organic compounds are liquid, use a microliter syringe to transfer it into the tube.Using a pasteur pipette, add the pre-weighed materials. Then, add deionized and deoxygenated water. Connect the tube to a vacuum line with a closed valve.Use a clamp to tightly hold the tube and immerse it in a dewar flask filled with liquid nitrogen. Leave the tube in the liquid nitrogen for approximately three minutes until the organics and water are completely frozen. While the tube is still immersed in liquid nitrogen, open the vacuum valve to remove the air from the headspace of the tube.After this, switch off the valve. Remove the tube from the liquid nitrogen and let the tube warm up to room temperature. When it has warmed, gently tap the bottom of the tube to release any remaining air bubbles from the solution into the head space.Repeat this freeze, pump, thaw cycle twice more. Then, while the tube is still immersed in liquid nitrogen, close the vacuum line and use the oxyhydrogen torch to seal the open end of the tube. After the tube has been sealed, transfer it into a small steel pipe equipped with screw caps.Seal the screw caps loosely to prevent any damage from pressure build up or tube failure. Place the pipe inside a temperature controlled furnace or oven and heat it to the desired temperature. Use a thermocouple inside the oven to monitor the temperature throughout the hydrothermal reaction.As soon as the reaction time is reached, remove the pipe from the oven and put the tube into a cold water bath to quench the experiment. First, make dichloromethane extraction solution that contains 8.8 micromolar dodecane, as an internal standard for gas chromatography. Transfer three milliliters of the extraction solution into a 10 milliliter glass vial.Then, use a tube cutter to open the tube and use a pasteur pipette to quickly transfer all of the product into the glass vial. Next, vortex the solution for one minute. Let the mineral particles settle for five minutes.After this, use a pasteur pipette to carefully transfer approximately one milliliter of the sample from the dichloromethane layer into a GC vial. Using a polycapillary column and a flame ionization detector, analyze the product distribution by gas chromatography as outlined in the text protocol. Build the GC calibration curves and use them to quantify the organic products.Then, calculate the reaction conversion as outlines in the text protocol. Use these conversions to determine if the mineral facilitates or slows down the hydrothermal organic transformations. This approach to study hydrothermal organic mineral interactions is demonstrated here using nitrobenzene with the mineral magnetite at a hydrothermal condition of 150 degrees Celsius and five bars for two hours.After the hydrothermal process, the tube containing no magnetite showed no color change, while the tube that did contain magnetite turned a brown color. This implies that an oxidation reaction took place, with magnetite being converted into hematite. Gas chromatography analysis is then performed to determine the amount of magnetite on nitrobenzene conversion.In the no mineral experiment, the calculated conversion for nitrobenzene is seen to be 5.2%However, in the presence of magnetite, the nitrobenzene conversion is 30.3%an increase by a factor of six. This suggests that magnetite can significantly promote the reaction of nitrobenzene at the utilized hydrothermal conditions. While attempting this procedure, it's important to remember to follow the SOP of using the oxyhydrogen torch.So following this procedure, other analytical methods like scan electron microscopy and gas chromatography mass spectroscopy can be performed in order to answer additional questions, like whether there's morphology change of the minerals and what are the molecules masses of unknown organic products. After its development, this technique paved the way for researchers in the field of hydrothermal organic chemistry to explore organic mineral interactions in natural hydrothermal systems.

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5.6K vistas.  Oakland University. This method can help answer key questions in the organic chemistry field such as how earth abundant minerals influence organic molecules in deep ocean hydrothermal systems. The main advantage of this technique is that it is low cost, easy to use, and reliable. Though this method can provide insight into organic mineral interactions in natural hydrothermal systems, it can also be applied to other areas such as hydrothermal treatment of organic glutens or biofused hydrothermal synthesis in gree...