Deoxygenation, Deaeration and Degassing: A Survey and Evaluation of Methods

Abstract

and classified according to their working principles. Consideration of these working principles reveals some inherent limitations of certain techniques and it may be concluded that the different methods complement each other in a number of aspects. Proton spin-lattice relaxation time measurements and polarographic analyses are used for evaluation of different deoxygenation methods.It is concluded that for most purposes the different methods yield satisfactory results if applied properly and within the inherent limitations of the techniques. When the presence of oxygen is very critical and its concentration must be reduced to very small amounts, a combination of methods appears advisable.Techniques for the removal of dissolved gases from liquids are reviewed

Synthesis of 3-Carbonyl Trisubstituted Furans via Pd-Catalyzed Aerobic Cycloisomerization Reaction: Development and Mechanistic Studies

“…To evaluate the effect of molecular oxygen in the reaction processing, a control experiment with system deoxygenation was performed using the freeze−pump−thaw deoxygenation technique, 24 resulting in 15% yield of 2a, while the absence of molecular sieves furnished the same product in 4% yield (Scheme 5A). This fact may be due to remaining O 2 being strongly adsorbed on the molecular sieves.…”

Conformational Effects of Regioisomeric Substitution on the Catalytic Activity of Copper/Calix[8]arene C−S Coupling

“…Toluene (Sigma-Aldrich, 99.5 %) was dried over Na/benzophenone, distilled under N 2 , and degassed via three freeze-pump-thaw cycles. [36] 1 H NMR spectra were recorded on a JEOL Eclipse spectrometer operating at 300 MHz and referenced to the residual solvent signal of C 2 D 2 Cl 4 (s, δ = 6.0 ppm). MALDI-TOF MS were acquired with a Bruker Microflex MALDI-TOF mass spectrometer using a 2,5-dihydroxybenzoic acid matrix.…”

“…Copper iodide (CuI), sodium thiophenolate (NaSC 6 H 5 ), bromobenzene (C 6 H 5 Br), 4‐fluorobromobenzene (BrC 6 H 4 F), 4‐bromobenzonitrile (BrC 6 H 4 CN), 4‐nitrobromobenzene (BrC 6 H 4 NO 2 ), iodobenzene (IC 6 H 5 ), 4‐nitroiodobenzene (IC 6 H 4 NO 2 ) and 4‐nitrochlorobenzene (ClC 6 H 4 NO 2 ) were purchased from Sigma‐Aldrich and used without further purification. Toluene (Sigma‐Aldrich, 99.5 %) was dried over Na/benzophenone, distilled under N 2 , and degassed via three freeze‐pump‐thaw cycles [36] . 1 H NMR spectra were recorded on a JEOL Eclipse spectrometer operating at 300 MHz and referenced to the residual solvent signal of C 2 D 2 Cl 4 (s, δ=6.0 ppm).…”

A multiscale X-ray phase-contrast tomography dataset of a whole human left lung

“…The sample mounting procedure involves alternated filling of the agar-ethanol mixture and gentle vacuum degassing to minimize the existing microbubbles from dissolved air in the solution environment and within the organ, thereby eliminating their interference with imaging. The degassing procedure used a membrane pump to directly pump 38 above the PET sample jar with the lid open in a sealed vacuum glass dryer. Prior to imaging, the PET jar containing the lung, ethanol solution, and agar embedding was placed in a custom-made sample holder to connect to the rotation stage at the synchrotron beamline 26 .…”