Desorption products during linear heating of copper zeolites with pre-adsorbed methanol

A newly developed technique is employed for the production of carbon and silicon cluster beams starting from gaseous compounds. It is based on the CO 2-laser-induced decomposition of molecular gases containing carbon and silicon, such as CO 2H2 and SiH 4, in a flow reactor. In order to decompose acetylene, SF 6 is used as a sensitizer. By introducing a skimmer into the reaction zone, the generated silicon and carbon clusters are transferred to free molecular flow and analyzed with a time-of-flight mass spectrometer. It is shown that the technique can be efficiently employed to produce fullerenes C 60 and C 70 and, in the case of silicon, ultrapure nanosized particles of up to 3-nm diameter.

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New Insights into the Kinetics of the Gas-Phase Oxidation of Hexafluoropropene

Progress in Reaction Kinetics and Mechanism ◽

10.3184/174751916x14764433065222 ◽

2016 ◽

Vol 41 (4) ◽

pp. 418-427 ◽

Cited By ~ 1

Author(s):

David Lokhat ◽

Maciej Starzak ◽

Deresh Ramjugernath

Keyword(s):

Gas Phase ◽

Oxidation Process ◽

Flow Reactor ◽

Packed Column ◽

Phase Reaction ◽

Analytical Technique ◽

Tubular Flow Reactor ◽

Gas Phase Oxidation ◽

Tubular Flow ◽

Kinetics Of

The gas-phase reaction of hexafluoropropene and molecular oxygen was investigated in a tubular flow reactor at 450 kPa and within a temperature range of 463–493 K using HFP/O2 mixtures containing 20–67% HFP on a molar basis. Capillary and packed column chromatography served as the main analytical technique. The reaction yielded HFPO, COF2, CF3COF, C2F4 and c-C3F6 as gas-phase products. High molecular weight oligomers were also formed. The oligomers were found to have a polyoxadifluoromethylene structure according to elemental and 19F NMR analysis. At 493 K HFP is proposed to undergo oxygen-mediated decomposition to difluorocarbene radicals, yielding greater quantities of difluorocarbene recombination products. Kinetic parameters for a revised model of the oxidation process were identified through least squares analysis of the experimental data.

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Translucent nanoparticle-based aerogel monoliths as 3-dimensional photocatalysts for the selective photoreduction of CO2 to methanol in a continuous flow reactor

Materials Horizons ◽

10.1039/c7mh00423k ◽

2017 ◽

Vol 4 (6) ◽

pp. 1115-1121 ◽

Cited By ~ 26

Author(s):

Felix Rechberger ◽

Markus Niederberger

Keyword(s):

Gas Phase ◽

Continuous Flow ◽

Flow Reactor ◽

Gas Phase Reactions ◽

3 Dimensional ◽

Continuous Flow Reactor

A newly developed prototype of a flow reactor enables the exploitation of nanoparticle based aerogel monoliths as macroscopically sized photocatalysts in gas phase reactions.

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A method for studying chain gas-phase processes in a complete mixing flow reactor with recording reaction mixture radiation

Russian Journal of Physical Chemistry A ◽

10.1134/s0036024409100148 ◽

2009 ◽

Vol 83 (10) ◽

pp. 1712-1714 ◽

Cited By ~ 4

Author(s):

G. N. Sargsyan

Keyword(s):

Gas Phase ◽

Flow Reactor ◽

Mixture Radiation

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Pressure dependent low temperature kinetics for CN + CH3CN: competition between chemical reaction and van der Waals complex formation

Physical Chemistry Chemical Physics ◽

10.1039/c6cp01982j ◽

2016 ◽

Vol 18 (22) ◽

pp. 15118-15132 ◽

Cited By ~ 14

Author(s):

Chantal Sleiman ◽

Sergio González ◽

Stephen J. Klippenstein ◽

Dahbia Talbi ◽

Gisèle El Dib ◽

...

Keyword(s):

Low Temperature ◽

Complex Formation ◽

Gas Phase ◽

Rate Coefficient ◽

Flow Reactor ◽

Slow Flow ◽

Phase Reaction ◽

Gas Phase Reaction ◽

Low Temperature Kinetics ◽

Temperature And Pressure

The gas phase reaction between the CN radical and acetonitrile CH3CN was investigated experimentally with a CRESU apparatus and a slow flow reactor as well as theoretically to explore the temperature and pressure dependence of its rate coefficient from 354 K down to 23 K.

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Preparation of isocyanates by carbamates thermolysis on the example of butyl isocyanate

Butlerov Communications ◽

10.37952/roi-jbc-01/19-58-4-40 ◽

2019 ◽

Vol 58 (4) ◽

pp. 40-47

Author(s):

Ratmir R. Dashkin ◽

◽

Dmitry A. Gordeev ◽

Khusrav Kh. Gafurov ◽

Sergey N. Mantrov ◽

...

Keyword(s):

Gas Phase ◽

High Performance ◽

Gas Flow ◽

Flow Reactor ◽

Packed Column ◽

Biologically Active ◽

Dibutyltin Dilaurate ◽

Reaction Products ◽

Uv Detector ◽

Laboratory Setup

Butyl isocyanate is widely distributed as a precursor for the production of a number of biologically active substances: fungicides, preservatives, insecticides, personal care products, etc. Nowadays, there are a number of methods for the preparation of isocyanates, which can be divided into liquid phase and gas phase. One of the perspective methods for the production of isocyanates is the thermolysis of carbamate and/or the actions of various reaction activating agents, accompanied by the elimination of alcohol, but this process is reversible, which greatly complicates its use in industry. The paper presents the results of studies of non-catalytic thermal decomposition of N-alkylcarbamates with the formation of alkylisocyanates on the example of butylisocyanate in the gas phase, flow reactor in a wide temperature range (200 to 450 °C). In addition, a series of experiments was carried out using a catalyst, dibutyltin dilaurate, in order to reduce the thermolysis temperature and increase the yield of the final product. To implement the isocyanate production process, an experimental laboratory setup, consisting of a gas flow meter (argon) regulator, a packed column (for heating) and a sorption solution tank, was developed and tested. The thermolysis of N-n-butylcarbamate was carried out in two variations: the preparation of an individual n-butylisocyanate and the passage of reaction products through a sorption solution linking the n-butyl isocyanate to N-n-butyl-N '-(1-phenylethyl)urea, which allows to estimate the yield of the target n-butylisocyanate without additional losses. The analysis of the obtained substances was carried out by high performance liquid chromatography with a UV detector (target product) and a mass detector (analysis of by-products). According to the results of research, a modification of the laboratory facility was proposed, as well as n-butylisocyanate was obtained with a yield of 49% on the basis of a new technique.

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Gaseous, PM<sub>2.5</sub> Mass, and Speciated Emission Factors from Laboratory Chamber Peat Combustion

10.5194/acp-2019-456 ◽

2019 ◽

Cited By ~ 1

Author(s):

John G. Watson ◽

Junji Cao ◽

L.W. Antony Chen ◽

Qiyuan Wang ◽

Jie Tian ◽

...

Keyword(s):

Organic Carbon ◽

Gas Phase ◽

Flow Reactor ◽

Combustion Efficiency ◽

Emission Factors ◽

Water Soluble ◽

Atmospheric Aging ◽

High Vapor ◽

Southern Florida ◽

Northern Alaska

Abstract. Peat fuels representing four biomes of boreal (western Russia and Siberia), temperate (northern Alaska, U.S.A.), subtropical (northern and southern Florida, U.S.A), and tropical (Borneo, Malaysia) regions were burned in a laboratory chamber to determine gas and particle emission factors (EFs). Tests with 25 % fuel moisture were conducted with predominant smoldering combustion conditions (average modified combustion efficiency [MCE] = 0.82 ± 0.08). Average fuel-based EFCO2 (carbon dioxide) are highest (1400 ± 38 g kg−1) and lowest (1073 ± 63 g kg−1) for the Alaskan and Russian peats, respectively. EFCO (carbon monoxide) and EFCH4 (methane) are ~12 %‒15 % and ~0.3 %‒0.9 % of EFCO2, in the range of 157‒171 g kg−1 and 3‒10 g kg−1, respectively. EFs for nitrogen species are at the same magnitude of EFCH4, with an average of 5.6 ± 4.8 and 4.7 ± 3.1 g kg−1 for EFNH3 (ammonia) and EFHCN (hydrogen cyanide); 1.9 ± 1.1 g kg−1 for EFNOx (nitrogen oxides); as well as 2.4 ± 1.4 and 2.0 ± 0.7 g kg−1 for EFNOy (reactive nitrogen) and EFN2O (nitrous oxide). An oxidation flow reactor (OFR) was used to simulate atmospheric aging times of ~2 and ~7 days to compare fresh (upstream) and aged (downstream) emissions. Filter-based EFPM2.5 varied by >4-fold (14‒61 g kg−1) without appreciable changes between fresh and aged emissions. The majority of EFPM2.5 consists of EFOC (organic carbon), with EFOC/EFPM2.5 ratios in the range of 52 %‒98 % for fresh emissions, and ~15 % degradation after aging. Reductions of EFOC (~7‒9 g kg−1) after aging are most apparent for boreal peats with the largest degradation in organic carbon that evolves at <140 °C, indicating the loss of high vapor pressure semi-volatile organic compounds upon aging. The highest EFLevoglucosan is found for Russian peat (~16 g kg−1), with ~35 %‒50 % degradation after aging. EFs for water-soluble OC (EFWSOC) accounts for ~20 %‒62 % of fresh EFOC. The majority (>95 %) of the total emitted carbon is in the gas phase with 54 %‒75 % CO2, followed by 8 %‒30 % CO. Nitrogen in the measured species explains 24 %‒52 % of the consumed fuel nitrogen with an average of 35 ± 11 %, consistent with past studies that report ~one- to two-thirds of the fuel nitrogen measured in biomass smoke. The majority (>99 %) of the total emitted nitrogen is in the gas phase, with an average of 16.7 % fuel N emitted as NH3 and 9.5 % of fuel N emitted as HCN. N2O and NOy constituted 5.7 % and 2.9 % of consumed fuel N. EFs from this study can be used to refine current emissions inventories.

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