Rhodium-Catalyzed [2+2+2] Cycloaddition of Diynes with Carbodiimides and Carbon Dioxide under Ambient Conditions

2014 ◽  
Vol 20 (8) ◽  
pp. 2169-2174 ◽  
Author(s):  
Masahiro Ishii ◽  
Fumiya Mori ◽  
Ken Tanaka
Keyword(s):  
Carbon Dioxide ◽  
Ambient Conditions

Efficient Carboxylation of Terminal Alkynes with Carbon Dioxide Catalyzed by Ligand‐Free Copper Catalyst under Ambient Conditions

2019 ◽  
Vol 8 (8) ◽  
pp. 1501-1505 ◽  
Author(s):  
Wan‐Hui Wang ◽  
Lihong Jia ◽  
Xiujuan Feng ◽  
Dingqiao Fang ◽  
Hongyu Guo ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Copper Catalyst ◽  
Terminal Alkynes ◽  
Ambient Conditions ◽  
Ligand Free

scholarly journals Zirconium-Based Metal Organic Frameworks for the Capture of Carbon Dioxide and Ethanol Vapour. A Comparative Study

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7620
Author(s):  
Meryem Saidi ◽  
Phuoc Hoang Ho ◽  
Pankaj Yadav ◽  
Fabrice Salles ◽  
Clarence Charnay ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Metal Organic Frameworks ◽  
Van Der Waals Interactions ◽  
Ambient Conditions ◽  
Ethanol Vapour ◽  
Metal Organic ◽  
Experimental Findings ◽  
Two Parameters ◽  
Low Coverage ◽  
Ethanol Adsorption

This paper reports on the comparison of three zirconium-based metal organic frameworks (MOFs) for the capture of carbon dioxide and ethanol vapour at ambient conditions. In terms of efficiency, two parameters were evaluated by experimental and modeling means, namely the nature of the ligands and the size of the cavities. We demonstrated that amongst three Zr-based MOFs, MIP-202 has the highest affinity for CO2 (−50 kJ·mol−1 at low coverage against around −20 kJ·mol−1 for MOF-801 and Muc Zr MOF), which could be related to the presence of amino functions borne by its aspartic acid ligands as well as the presence of extra-framework anions. On the other side, regardless of the ligand size, these three materials were able to adsorb similar amounts of carbon dioxide at 1 atm (between 2 and 2.5 µmol·m−2 at 298 K). These experimental findings were consistent with modeling studies, despite chemisorption effects, which could not be taken into consideration by classical Monte Carlo simulations. Ethanol adsorption confirmed these results, higher enthalpies being found at low coverage for the three materials because of stronger van der Waals interactions. Two distinct sorption processes were proposed in the case of MIP-202 to explain the shape of the enthalpic profiles.

scholarly journals Comparing the Use of High- to Low-Cost Black Carbon and Carbon Dioxide Sensors for Characterizing On-Road Diesel Truck Emissions

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6714
Author(s):  
Rebecca A. Sugrue ◽  
Chelsea V. Preble ◽  
Thomas W. Kirchstetter
Keyword(s):  
Carbon Dioxide ◽  
Black Carbon ◽  
Emission Factor ◽  
Lower Cost ◽  
Low Cost ◽  
Ambient Air ◽  
Source Characterization ◽  
Ambient Conditions ◽  
Heavy Duty Diesel ◽  
Carbon Dioxide Co2

The exhaust plume capture method is a commonly used approach to measure pollutants emitted by in-use heavy-duty diesel trucks. Lower cost sensors, if used in place of traditional research-grade analyzers, could enable wider application of this method, including use as a monitoring tool to identify high-emitting trucks that may warrant inspection and maintenance. However, low-cost sensors have for the most part only been evaluated under ambient conditions as opposed to source-influenced environments with rapidly changing pollutant concentrations. This study compared black carbon (BC) emission factors determined using different BC and carbon dioxide (CO2) sensors that range in cost from $200 to $20,000. Controlled laboratory experiments show that traditional zero and span steady-state calibration checks are not robust indicators of sensor performance when sampling short duration concentration peaks. Fleet BC emission factor distributions measured at two locations at the Port of Oakland in California with 16 BC/CO2 sensor pairs were similar, but unique sensor pairs identified different high-emitting trucks. At one location, the low-cost PP Systems SBA-5 agreed on the classification of 90% of the high emitters identified by the LI-COR LI-7000 when both were paired with the Magee Scientific AE33. Conversely, lower cost BC sensors when paired with the LI-7000 misclassified more than 50% of high emitters when compared to the AE33/LI-7000. Confidence in emission factor quantification and high-emitter identification improves with larger integrated peak areas of CO2 and especially BC. This work highlights that sensor evaluation should be conducted under application-specific conditions, whether that be for ambient air monitoring or source characterization.

A highly active copper catalyst for the hydrogenation of carbon dioxide to formate under ambient conditions

2020 ◽  
Vol 49 (9) ◽  
pp. 2994-3000
Author(s):  
Karan Chaudhary ◽  
Manoj Trivedi ◽  
D. T. Masram ◽  
Abhinav Kumar ◽  
Girijesh Kumar ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Copper Catalyst ◽  
Catalytic Conversion ◽  
Ambient Conditions ◽  
Turnover Number ◽  
Highly Active ◽  
Tin Metal ◽  
Hydrogenation Of Carbon Dioxide

Catalytic conversion of CO2via hydrogenation using in situ gaseous H2 (granulated tin metal and concentrated HCl) to produce the formate salt (HCO2−) with turnover number (TON) values of 326 to 1.065 × 105 in 12 h to 48 h of reaction at 25 °C to 80 °C has been reported.

Measurements of Laminar Flame Speeds of Alternative Gaseous Fuel Mixtures

2015 ◽  
Vol 137 (3) ◽  
Author(s):  
Ahmed S. Ibrahim ◽  
Samer F. Ahmed
Keyword(s):  
Carbon Dioxide ◽  
Alternative Fuels ◽  
Laminar Flame ◽  
Engine Performance ◽  
Fuel Mixture ◽  
Gaseous Fuel ◽  
Combustion Engines ◽  
Liquefied Petroleum Gas ◽  
Ambient Conditions ◽  
Fuel Mixtures

Global warming and the ever increasing emission levels of combustion engines have forced the engine manufacturers to look for alternative fuels for high engine performance and low emissions. Gaseous fuel mixtures such as biogas, syngas, and liquefied petroleum gas (LPG) are new alternative fuels that have great potential to be used with combustion engines. In the present work, laminar flame speeds (SL) of alternative fuel mixtures, mainly LPG (60% butane, 20% isobutane, and 20% propane) and methane have been studies using the tube method at ambient conditions. In addition, the effect of adding other fuels and gases such as hydrogen, oxygen, carbon dioxide, and nitrogen on SL has also been investigated. The results show that any change in the fuel mixture composition directly affects SL. Measurements of SL of CH4/LPG–air mixtures have found to be about 56 cm/s at ø = 1.1 with 60% LPG in the mixture, which is higher than SL of both pure fuels at the same ø. Moreover, the addition of H2 and O2 to the fuel mixtures increases SL notably, while the addition of CO2/N2 mixture to the fuel mixture, to simulate the EGR effect, decreases SL of CH4/LPG–air mixtures.

CO2 driven changes in leaf biochemistry may have influenced fire behaviour at the Triassic-Jurassic boundary

2020 ◽  
Author(s):  
Sarah Baker ◽  
Rebecca Dewhirst ◽  
Jennifer McElwain ◽  
Matthew Haworth ◽  
Claire Belcher
Keyword(s):  
Carbon Dioxide ◽  
Environmental Changes ◽  
Biochemical Properties ◽  
Flame Length ◽  
Gas Chromatography Mass Spectrometry ◽  
Atmospheric Conditions ◽  
Leaf Chemistry ◽  
Fire Behaviour ◽  
Ambient Conditions ◽  
Carbon Dioxide Concentrations

<p>The Triassic-Jurassic Boundary marks one of the largest mass extinction events of the Phanerozoic. Across the boundary, a rise in carbon-dioxide levels and global temperatures are hypothesized to have driven significant environmental changes inducing a major floral turnover, causing vegetation structure, composition and leaf morphology to alter, and inferred wildfire activity to increase.</p><p>An example of these changes can be observed at the Astartekløft site in East Greenland, where previous work identified a change in flora from broad-leaved conifer dominated to an assemblage dominated by narrow leaved conifers, coeval with a five-fold increase in charcoal abundances.</p><p>Variations in carbon-dioxide concentrations have been shown to be capable of influencing leaf chemistry. It could therefore be hypothesized that carbon-dioxide-driven climate changes across the Triassic-Jurassic boundary may have been capable of not only inducing changes in leaf morphological fuel properties, but also variations in biochemical properties that are both capable of altering wildfire behaviour.</p><p>In order to assess this, we selected three plant species that have ancient evolutionary origins and correspond to the dominant leaf morphotypes of litter-forming vegetation observed at the Astartekløft site across the Triassic-Jurassic boundary. We grew these species in current ambient and high carbon-dioxide (Triassic-Jurassic boundary) atmospheric conditions and analysed variations in the chemistry of the leaves, using gas chromatography mass spectrometry, and assessed aspects of their flammability using micro-calorimetry. These data were used to inform a fire behaviour model to produce estimates of variations in fire behaviour, such as surface fire spread, flame length and fireline intensity across the Triassic-Jurassic boundary at Astartekløft.</p><p>Our results reveal a change in leaf chemistry that is expressed as a suppression of volatile content in the three species grown under elevated carbon-dioxide concentrations, compared to those grown under ambient conditions. By accounting for these variations in a fire behaviour model, we estimate that fire behaviour was more extreme prior to the increase in carbon-dioxide across the boundary, suggesting a switch from a period of infrequent but intense fast-moving surface fires during the Triassic, to a period of frequent but low intensity and slow spreading fires during the earliest Jurassic. Our results indicate that that increases in carbon-dioxide concentrations may have impacted leaf chemistry and thus flammability, and may therefore have played an interesting role in determining fire behaviour characteristics during this marked period of Earth’s past.  </p>

scholarly journals Impact of seawater <i>p</i>CO<sub>2</sub> on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with <i>Ammonia tepida</i>

2010 ◽  
Vol 7 (1) ◽  
pp. 81-93 ◽  
Author(s):  
D. Dissard ◽  
G. Nehrke ◽  
G. J. Reichart ◽  
J. Bijma
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Benthic Foraminifera ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Planktonic Foraminifera ◽  
Ambient Conditions ◽  
Precipitated Calcium Carbonate ◽  
Shell Weight ◽  
Dissolved Carbon

Abstract. Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Hence, their response to an acidifying ocean may have important consequences for future inorganic carbon cycling. To assess the sensitivity of benthic foraminifera to changing carbon dioxide levels and subsequent alteration in seawater carbonate chemistry, we cultured specimens of the shallow water species Ammonia tepida at two concentrations of atmospheric CO2 (230 and 1900 ppmv) and two temperatures (10 °C and 15 °C). Shell weights and elemental compositions were determined. Impact of high and low pCO2 on elemental composition are compared with results of a previous experiment were specimens were grown under ambient conditions (380 ppvm, no shell weight measurements of specimen grown under ambient conditions are, however, available). Results indicate that shell weights decrease with decreasing [CO32−], although calcification was observed even in the presence of calcium carbonate under-saturation, and also decrease with increasing temperature. Thus both warming and ocean acidification may act to decrease shell weights in the future. Changes in [CO32−] or total dissolved inorganic carbon do not affect the Mg distribution coefficient. On the contrary, Sr incorporation is enhanced under increasing [CO32−]. Implications of these results for the paleoceanographic application of foraminifera are discussed.

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