simulation-early-earth-hydrothermal-chimneys-thermal-gradient

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment

Deep sea hydrothermal vents are self-organizing precipitates generated from geochemical disequilibria and have been proposed as a possible setting for the ...

The University of Tulsa

Following the expiration of the patents on fused-filament-fabrication (FFF), the availability and uses of this 3D-printing technology have exploded. Several recent reports describe how conductive composites can be used with FFF printers to generate 3D-printed electrodes (3DEs) for energy storage and electrochemical analysis. As printed materials, these electrodes have very high impedance values because of the high content of insulating thermoplastic required for FFF printers. To overcome this challenge, deposition of metals or activation with harsh chemicals has previously been employed. Here, a benign postprinting process was developed using the electrolysis of water to selectively remove the insulating thermoplastic (polylactic acid) via saponification. Optimization of the hydroxide-treatment process was found to reduce the impedance of 3DEs by 3 orders of magnitude in filaments from two manufacturers. This electrolysis-activation strategy offers a safe, accessible, and affordable means for improving the electrochemical performance of 3DEs. Here, the ability of these modified 3DEs to be used for electrochemical analysis and integrated into complex electrochemical cells is demonstrated.

Electrolysis Activation of Fused-Filament-Fabrication 3D-Printed Electrodes for Electrochemical and Spectroelectrochemical Analysis.

Ultraviolet-visible (UV-vis) spectroscopy represents one of the most popular analytical techniques in chemical research labs. A variety of vendors provide instruments that are suited for the analysis of liquid samples at moderate concentrations. However, to accommodate more specialized experiments, expensive accessories are required and often do not fit the specific needs of experimental scientists. In this work, we present a generalized adapter that can be 3D printed and used with existing spectrometers to enable a wide array of experiments to be performed. In the case of liquid samples, we provide a method for dramatically reducing the price of a quartz cuvette with minimal impact on performance. Through simple modification of the design, cuvettes with various path lengths can be prepared. Additionally, we illustrate the ability to turn any sample container into a working cuvette to simplify experimental protocols, prevent contamination risks, and further reduce costs. This strategy also enables gaseous and solid samples to be evaluated easily and reproducibly. Furthermore, we demonstrate how this concept can be extended to interface additional instrumentation with a commercial UV-vis spectrometer. All of the digital designs are provided under a creative commons license to enable other researchers to modify and adapt the designs for their unique experimental requirements.

3D Printed UV-Visible Cuvette Adapter for Low-Cost and Versatile Spectroscopic Experiments.

A variety of arenes and heteroarenes are brominated in good to excellent yields using -bromosuccinimide (NBS) under mild and practical conditions. According to mechanistic investigations described within, the reaction is speculated to proceed via activation of NBS through a visible-light photoredox pathway utilizing erythrosine B as a photocatalyst. A photo-oxidative approach effectively amplifies the positive polarization on the bromine atom of the NBS reagent. This increase in the electrophilic nature of NBS results in drastically reduced reaction times and diversion from competing light-promoted reactive pathways.

Organic Dye-Catalyzed, Visible-Light Photoredox Bromination of Arenes and Heteroarenes Using -Bromosuccinimide.

Seven FDA-certified food dyes have been investigated as organocatalysts. As a result, Fast Green FCF and Brilliant Blue FCF have been discovered as catalysts for the chlorination of a wide range of arenes and heteroarenes in moderate to excellent yields and high regioselectivity. Mechanistic investigations of the separate systems indicate that different modes of activation are in operation, with Fast Green FCF being a light-promoted photoredox catalyst that is facilitating a one-electron oxidation of -chlorosuccinimide (NCS) and Brilliant Blue FCF serving as a chlorine-transfer catalyst in its sulfonphthalein form with 1,3-dichloro-5,5-dimethylhydantoin (DCDMH) as stoichiometric chlorine source. Dearomatization of naphthol and indole substrates was observed in some examples using the Brilliant Blue/DCDMH system.

Gabriel LeBlanc

The University of Tulsa

Simulation of Early Earth Hydrothermal Chimneys in a Thermal Gradient Environment