Anion effects in the formation of the active catalyst in the Ruhrchemie – Rhône-Poulenc aqueous biphasic hydroformylation process. Are there any?

2005 ◽  
Vol 83 (6-7) ◽  
pp. 1033-1036 ◽  
Author(s):  
József Kovács ◽  
Ferenc Joó ◽  
Carl D Frohning
Keyword(s):  
Aqueous Solutions ◽  
Active Catalyst ◽  
Water Soluble ◽  
Catalyst Precursor ◽  
Solution Ph ◽  
Aqueous Biphasic ◽  
First Time ◽  
Close Analogue

The water soluble [Rh(OAc)(CO)(mtppms)2] containing monosulfonated triphenylphosphine ligands was prepared for the first time and its hydrogenation was studied in aqueous solutions. In the presence of additional mtppms, the reaction yielded [RhH(CO)(mtppms)3], a close analogue of [RhH(CO)(mtppts)3], the immediate catalyst precursor in the Ruhrchemie – Rhône-Poulenc aqueous biphasic hydroformylation process. The extent of the [Rh(OAc)(CO)(mtppms)2] → [RhH(CO)(mtppms)3] transformation strongly depended on the solution pH, similar to the case of the hydrogenation of [RhCl(CO)(mtppms)2] studied earlier. In this respect, RhCl3·aq and Rh(OAc)3·aq can be used equally well for the in situ preformation of [RhH(CO)(mtppts)3], although the latter is the preferred choice in the industrial process.Key words: rhodium, water-soluble, hydrides, sulfonated phosphines, biphasic.

scholarly journals Photo-transformation of aqueous nitroguanidine and 3-nitro-1,2,4-triazol-5-one : emerging munitions compounds

2021 ◽  
Author(s):  
Julie Becher ◽  
Samuel Beal ◽  
Susan Taylor ◽  
Katerina Dontsova ◽  
Dean Wilcox
Keyword(s):  
Aqueous Solutions ◽  
Degradation Products ◽  
Pure Water ◽  
Transformation Products ◽  
Water Soluble ◽  
Uv Exposure ◽  
Degradation Pathways ◽  
Solution Ph ◽  
Photo Degradation ◽  
Degradation Rates

Two major components of insensitive munition formulations, nitroguanidine (NQ) and 3-nitro-1,2,4-triazol-5-one (NTO), are highly water soluble and therefore likely to photo-transform while in solution in the environment. The ecotoxicities of NQ and NTO solutions are known to increase with UV exposure, but a detailed accounting of aqueous degradation rates, products, and pathways under different exposure wavelengths is currently lacking. We irradiated aqueous solutions of NQ and NTO over a 32-h period at three ultraviolet wavelengths and analyzed their degradation rates and transformation products. NQ was completely degraded by 30 min at 254 nm and by 4 h at 300 nm, but it was only 10% degraded after 32 h at 350 nm. Mass recoveries of NQ and its transformation products were >80% for all three wavelengths. NTO degradation was greatest at 300 nm with 3% remaining after 32 h, followed by 254 nm (7% remaining) and 350 nm (20% remaining). Mass recoveries of NTO and its transformation products were high for the first 8 h but decreased to 22–48% by 32 h. Environmental half-lives of NQ and NTO in pure water were estimated as 4 and 6 days, respectively. We propose photo-degradation pathways for NQ and NTO supported by observed and quantified degradation products and changes in solution pH.

scholarly journals Aqueous-biphasic hydroformylation of 1-hexene catalyzed by the complex HCo(CO)[P(o-C6H4SO3Na)]3

2017 ◽  
Vol 61 (2) ◽  
Author(s):  
María Modroño-Alonso ◽  
William Castro ◽  
Francisco Lopez-Linares ◽  
Merlín Rosales ◽  
Pablo Jose Baricelli
Keyword(s):  
Cobalt Complex ◽  
Nitrogen Atmosphere ◽  
Water Soluble ◽  
Catalyst Precursor ◽  
Reaction Conditions ◽  
Moderate Reaction ◽  
H Nmr ◽  
Reductive Carbonylation ◽  
Aqueous Biphasic ◽  
C Nmr

The water soluble cobalt complex HCo(CO)[P(<em>o</em>-C<sub>6</sub>H<sub>4</sub>SO-<sub>3</sub>Na)]<sub>3</sub> was used as catalyst precursor for the biphasic aqueous hydroformylation of 1-hexene. The complex was synthesized by reductive carbonylation of CoCl<sub>2</sub>.6H<sub>2</sub>O in the presence of <em>o</em>-TPPTS ([P(<em>o</em>-C<sub>6</sub>H<sub>4</sub>SO<sub>3</sub>Na)]<sub>3</sub>) under nitrogen atmosphere and characterized by FTIR, <sup>1</sup>H NMR and <sup>31</sup>P {1H} NMR, <sup>13</sup>C NMR, DEPT – 135, COSY, HSQC, MS (ESI). The catalytic activity of the complex in the biphasic hydroformylation reaction of 1-hexene was evaluated under moderate reaction conditions. The pressure and temperature were varied from 4137 – 7584 kPa (600-1100 psi) of syngas and from 353 – 383 K (80 – 110 °C), respectively. The 1-hexene concentration was varied from 0.021-0,11M and the catalyst from 4x10<sup>-4</sup> - 1.1x10<sup>-3</sup> M. The best conversion at 363 K and 7584 kPa and 7.5 h was 62% with selectivity towards aldehydes (heptanal and 2-methyl-hexanal) of 66% to with l/b ratio of 2.6. The recycling of the catalytic precursor after four successive times, did not show any loss on the activity, having selectivity towards aldehyde up to 60%.

Probing dissolved CO2(aq) in aqueous solutions for CO2 electro-reduction and storage

2022 ◽  
Author(s):  
Jiachen Li ◽  
Jinyu Guo ◽  
Hongjie Dai
Keyword(s):  
Aqueous Solutions ◽  
Co2 Capture ◽  
High Pressures ◽  
Dynamic Monitoring ◽  
State Transitions ◽  
Ir Absorption ◽  
Large Hysteresis ◽  
Co2 Electroreduction ◽  
First Time

CO2 dissolved in aqueous solutions is of wide ranging importance from CO2 capture, storage and photo-/electro-reduction in the fight against global warming, to CO2 analysis in various liquids including natural waterbodies and consumer drinking products. Here we developed micro-scale infrared (IR) spectroscopy for in-situ dynamic monitoring and quantitating CO2(aq) in aqueous solutions with high time resolutions under various conditions including CO2 gas bubbling and high pressures. The quantized CO2(g) rotational state transitions were observed to quench when dissolved in water to form CO2(aq) solvated by water molecules, accompanied by increased H2O IR absorption. An accurate CO2 molar extinction coefficient ε was derived for in-situ CO2(aq) quantification up to 58 atm. For the first time, we directly measured CO2(aq) concentrations in electrolytes under CO2(g) bubbling and high pressure conditions. In KHCO3 electrolytes with CO2(aq) > ~ 1 M, CO2 electroreduction (CO2RR) to formate reaches > 98% Faradaic efficiencies on copper (Cu2O/Cu) based electrocatalyst. Further, we probed CO2 dissolution/desolvation kinetics important to energy and environmental applications dynamically, revealing large hysteresis and ultra-slow reversal of CO2(aq) supersaturation in water, with implications to CO2 capture, storage and supersaturation phenomena in natural water bodies.

Synthesis of sodium polyacrylate–bentonite using in situ polymerization for Pb2+ removal from aqueous solutions

RSC Advances ◽  
2016 ◽  
Vol 6 (53) ◽  
pp. 48145-48154 ◽  
Author(s):  
Youjun He ◽  
Meishan Pei ◽  
Ni Xue ◽  
Luyan Wang ◽  
Wenjuan Guo
Keyword(s):  
Heavy Metal ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
In Situ Polymerization ◽  
Sodium Polyacrylate ◽  
First Time

A sodium polyacrylate–bentonite material (PAANa–Bent), as an adsorbent for heavy metal ions, is synthesized for the first time using in situ polymerization.

Novel structurally tuned DAMN receptor for “in situ” diagnosis of bicarbonate in environmental waters

The Analyst ◽  
2016 ◽  
Vol 141 (8) ◽  
pp. 2367-2370 ◽  
Author(s):  
Masood Ayoub Kaloo ◽  
Ramya Sunder Raman ◽  
Jeyaraman Sankar
Keyword(s):  
Water Soluble ◽  
Environmental Waters ◽  
First Time

A novel receptor for specific and prompt bicarbonate anion (HCO3−) recognition is presented. HCO3− triggers facile ICT, which provides “in situ” recognition of water soluble carbonates. For the first time, “on-site” estimation of HCO3− in environmental waters is demonstrated.

scholarly journals New insight on the simultaneous H2 and HNO2 production in concentrated HNO3 aqueous solutions under alpha radiation

RSC Advances ◽  
2021 ◽  
Vol 11 (20) ◽  
pp. 12141-12152
Author(s):  
Raluca M. Musat ◽  
Jean-Luc Roujou ◽  
Vincent Dauvois ◽  
Muriel Ferry ◽  
Carole Marchand ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Precise Determination ◽  
Alpha Radiation ◽  
System P ◽  
Set Up ◽  
First Time

For the first time ever, a specially designed set-up, coupled to the CEMHTI cyclotron allowed in situ monitoring of HNO2 and precise determination of H2 production in the external α radiolysis of HNO3 solution, while ensuring no perturbation of the investigated system.

scholarly journals An Investigation of the Adsorption of Xanthate on Bornite in Aqueous Solutions using an Atomic Force Microscope

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 906
Author(s):  
Jinhong Zhang
Keyword(s):  
Aqueous Solutions ◽  
Atomic Force Microscope ◽  
Force Measurement ◽  
Attenuated Total Reflection ◽  
Solution Ph ◽  
Substrate Adhesion ◽  
Atomic Force ◽  
Measurement Results ◽  
Industry Practice

An atomic force microscope (AFM) was applied to study of the adsorption of xanthate on bornite surfaces in situ in aqueous solutions. AFM images showed that xanthate, i.e., potassium ethyl xanthate (KEX) and potassium amyl xanthate (PAX), adsorbed strongly on bornite, and the adsorbate bound strongly with the mineral surface without being removed by flushing with ethanol alcohol. The AFM images also showed that the adsorption increased with the increased collector concentration and contact time. Xanthate adsorbed on bornite in a similar manner when the solution pH changed to pH 10. The AFM force measurement results showed that the probe–substrate adhesion increased due to the adsorption of xanthate on bornite. The sharp “jump-in” and “jump-off” points on force curve suggest that the adsorbate is not “soft” in nature, ruling out the existence of dixanthogen, an oily substance. Finally, the ATR-FTIR (attenuated total reflection-Fourier-transform infrared) result confirms that the adsorbate on bornite in xanthate solutions is mainly in the form of insoluble cuprous xanthate (CuX) instead of dixanthogen. This xanthate/bornite adsorption mechanism is very similar to what is obtained with the xanthate/chalcocite system, while it is different from the xanthate/chalcopyrite system, for which oily dixanthogen is the main adsorption product on the chalcopyrite surface. The present study helps clarify the flotation mechanism of bornite in industry practice using xanthate as a collector.

scholarly journals Determination of Cadmium (II) in Aqueous Solutions by In Situ MID-FTIR-PLS Analysis Using a Polymer Inclusion Membrane-Based Sensor: First Considerations

Molecules ◽  
2020 ◽  
Vol 25 (15) ◽  
pp. 3436 ◽  
Author(s):  
René González-Albarrán ◽  
Josefina de Gyves ◽  
Eduardo Rodríguez de San Miguel
Keyword(s):  
Aqueous Solutions ◽  
Analytical Sensitivity ◽  
Concentration Difference ◽  
Inclusion Membrane ◽  
Polymer Inclusion Membrane ◽  
Pls Analysis ◽  
First Time

Environmental monitoring is one of the most dynamically developing branches of chemical analysis. In this area, the use of multidimensional techniques and methods is encouraged to allow reliable determinations of metal ions with portable equipment for in-field applications. In this regard, this study presents, for the first time, the capabilities of a polymer inclusion membrane (PIM) sensor to perform cadmium (II) determination in aqueous solutions by in situ visible (VIS) and Mid- Fourier transform infrared spectroscopy (MID-FTIR) analyses of the polymeric films, using a partial least squares (PLS) chemometric approach. The influence of pH and metal content on cadmium (II) extraction, the characterization of its extraction in terms of the adsorption isotherm, enrichment factor and extraction equilibrium were studied. The PLS chemometric algorithm was applied to the spectral data to establish the relationship between cadmium (II) content in the membrane and the absorption spectra. Furthermore, the developed MID-FTIR method was validated through the determination of the figures of merit (accuracy, linearity, sensitivity, analytical sensitivity, minimum discernible concentration difference, mean selectivity, and limits of detection and quantitation). Results showed reliable calibration curves denoting systems’ potentiality. Comparable results were obtained in the analysis of real samples (tap, bottle, and pier water) between the new MID-FTIR-PLS PIM based-sensor and F-AAS.

Poly(ionic liquid)s as phase splitting promoters in aqueous biphasic systems

2015 ◽  
Vol 17 (41) ◽  
pp. 27462-27472 ◽  
Author(s):  
Karen G. João ◽  
Liliana C. Tomé ◽  
Mehmet Isik ◽  
David Mecerreyes ◽  
Isabel M. Marrucho
Keyword(s):  
Ionic Liquid ◽  
Aqueous Solutions ◽  
Aqueous Biphasic Systems ◽  
Aqueous Biphasic ◽  
Biphasic Systems ◽  
Poly Ionic Liquid ◽  
First Time

The ability of hydrophilic pyrrolidinium-based PILs to promote phase splitting in aqueous solutions of K3PO4 is disclosed in this work for the first time.

Probing the Dynamic Self-Assembly Behaviour of Photoswitchable Wormlike Micelles in Real Time

2018 ◽  
Author(s):  
Elaine A. Kelly ◽  
Judith E. Houston ◽  
Rachel Evans
Keyword(s):  
Real Time ◽  
Absorption Spectroscopy ◽  
Self Assembly ◽  
Uv Light ◽  
Wormlike Micelles ◽  
Tetraethylene Glycol ◽  
Light Illumination ◽  
First Time ◽  
Dependent Processes

Understanding the dynamic self-assembly behaviour of azobenzene photosurfactants (AzoPS) is crucial to advance their use in controlled release applications such as<i></i>drug delivery and micellar catalysis. Currently, their behaviour in the equilibrium <i>cis-</i>and <i>trans</i>-photostationary states is more widely understood than during the photoisomerisation process itself. Here, we investigate the time-dependent self-assembly of the different photoisomers of a model neutral AzoPS, <a>tetraethylene glycol mono(4′,4-octyloxy,octyl-azobenzene) </a>(C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>) using small-angle neutron scattering (SANS). We show that the incorporation of <i>in-situ</i>UV-Vis absorption spectroscopy with SANS allows the scattering profile, and hence micelle shape, to be correlated with the extent of photoisomerisation in real-time. It was observed that C<sub>8</sub>AzoOC<sub>8</sub>E<sub>4</sub>could switch between wormlike micelles (<i>trans</i>native state) and fractal aggregates (under UV light), with changes in the self-assembled structure arising concurrently with changes in the absorption spectrum. Wormlike micelles could be recovered within 60 seconds of blue light illumination. To the best of our knowledge, this is the first time the degree of AzoPS photoisomerisation has been tracked <i>in</i><i>-situ</i>through combined UV-Vis absorption spectroscopy-SANS measurements. This technique could be widely used to gain mechanistic and kinetic insights into light-dependent processes that are reliant on self-assembly.

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