1,801 results match your criteria hydrogen separations

Exploring the Potential Application of Matrimid and ZIFs-Based Membranes for Hydrogen Recovery: A Review.

Polymers (Basel) 2021 Apr 15;13(8). Epub 2021 Apr 15.

Departamento de Ingenierías Química y Biomolecular, ETSIIyT, Universidad de Cantabria, Avda. de Los Castros s/n, 39005 Santander, Spain.

Hydrogen recovery is at the center of the energy transition guidelines promoted by governments, owing to its applicability as an energy resource, but calls for energetically nonintensive recovery methods. The employment of polymeric membranes in selective gas separations has arisen as a potential alternative, as its established commercial availability demonstrates. However, enhanced features need to be developed to achieve adequate mechanical properties and the membrane performance that allows the obtention of hydrogen with the required industrial purity. Read More

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Divorce in the two-component BVMO family: the single oxygenase for enantioselective chemo-enzymatic Baeyer-Villiger oxidations.

Org Biomol Chem 2021 Apr;19(15):3441-3450

Aix Marseille Univ, CNRS, Centrale Marseille, iSm2 UMR 7313, Marseille, France.

Two-component flavoprotein monooxygenases consist of a reductase and an oxygenase enzyme. The proof of functionality of the latter without its counterpart as well as the mechanism of flavin transfer remains unanswered beyond doubt. To tackle this question, we utilized a reductase-free reaction system applying purified 2,5-diketocamphane-monooxygenase I (2,5-DKCMO), a FMN-dependent type II Baeyer-Villiger monooxygenase, and synthetic nicotinamide analogues (NCBs) as dihydropyridine derivatives for FMN reduction. Read More

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Gas Separation by Mixed Matrix Membranes with Porous Organic Polymer Inclusions within -Hydroxypolyamides Containing -Terphenyl Moieties.

Polymers (Basel) 2021 Mar 18;13(6). Epub 2021 Mar 18.

Surfaces and Porous Materials (SMAP), Associated Research Unit to CSIC, Faculty of Science, University of Valladolid, Paseo Belén 7, 47011 Valladolid, Spain.

A hydroxypolyamide (HPA) manufactured from 2,2-bis(3-amino-4-hydroxy phenyl)-hexafluoropropane (APAF) diamine and 5'-terbutyl--terphenyl-4,4''-dicarboxylic acid chloride (tBTpCl), and a copolyimide produced by stochiometric copolymerization of APAF and 4,4'-(hexafluoroisopropylidene) diamine (6FpDA), using the same diacid chloride, were obtained and used as polymeric matrixes in mixed matrix membranes (MMMs) loaded with 20% (/) of two porous polymer networks (triptycene-isatin, PPN-1, and triptycene-trifluoroacetophenone, PPN-2). These MMMs, and also the thermally rearranged membranes (TR-MMMs) that underwent a thermal treatment process to convert the o-hydroxypolyamide moieties to polybenzoxazole ones, were characterized, and their gas separation properties evaluated for H, N, O, CH, and CO. Both TR process and the addition of PPN increased permeability with minor decreases in selectivity for all gases tested. Read More

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Modulating solvation interactions of deep eutectic solvents formed by ammonium salts and carboxylic acids through varying the molar ratio of hydrogen bond donor and acceptor.

J Chromatogr A 2021 Apr 18;1643:462011. Epub 2021 Feb 18.

Ames Laboratory-USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States. Electronic address:

Deep eutectic solvents (DESs) have gained increasing popularity in separation science due to the fact that their physico-chemical properties can be easily fine-tuned by varying the type or ratio of hydrogen bond acceptor (HBA) and hydrogen bond donor (HBD). While it is well-known that the molar ratio of HBA/HBD affects the melting point of a eutectic mixture, much less is understood regarding its effect on the magnitude of individual solvation interactions. This is largely due to the fact that established solvatochromic dye methods lack sensitivity when the HBA/HBD ratio is varied slightly in a eutectic mixture. Read More

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Preparation and characterization of poly(3-mercaptopropyl)methylsiloxane functionalized silica particles and their further modification for silver ion chromatography and enantioselective high-performance liquid chromatography.

J Chromatogr A 2021 Apr 15;1643:462069. Epub 2021 Mar 15.

Institute of Pharmaceutical Sciences, Pharmaceutical (Bio-)Analysis, University of Tübingen, Auf der Morgenstelle 8, 72076 Tübingen, Germany. Electronic address:

The present work reports on the preparation of polythiol-functionalized silica particles by thermally and photo-initiated radical addition reactions using poly(3-mercaptopropyl)methylsiloxane (PMPMS) as sulfhydryl group-rich surface modification reagent. Prior to surface modification with PMPMS, the silica was vinylized with vinyl trimethoxysilane. Finally, the usefulness of the thiolated silica particles was demonstrated by their further modification for various HPLC applications such as argentation chromatography and chiral separations. Read More

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Protein-induced conformational change in glycans decreases the resolution of glycoproteins in hydrophilic interaction liquid chromatography.

J Sep Sci 2021 Apr 31;44(8):1581-1591. Epub 2021 Mar 31.

Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana, USA.

An understanding of why hydrophilic interaction liquid chromatography gives a higher resolution for glycans than for glycoproteins would facilitate column improvements. Separations of the glycoforms of ribonuclease B compared to its released glycans were studied using a commercial hydrophilic interaction liquid chromatography column. The findings were used to devise a new hydrophilic interaction liquid chromatography column. Read More

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Limited Proteolysis and Gel Electrophoresis in the Presence of Metal Cations: Au(III)-binding Luminescent Domain in Serum Albumins.

J Vis Exp 2021 01 21(167). Epub 2021 Jan 21.

Department of Physics and Optical Science, Center for Biomedical Engineering & Science, The University of North Carolina;

The purpose of the presented protocols is to determine the domain of Au(III) binding in BSA. The BSA-Au(III) compound exhibits ultraviolet (UV)-excitable red luminescence (λem = 640 nm), with unusual Stokes shifts compared to the innate UV/blue fluorescence arising from the aromatic residues. Red-luminescent complexes are formed in highly alkaline conditions above pH 10 and require a conformation change within the protein to occur. Read More

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January 2021

Carbon hollow fiber membranes for a molecular sieve with precise-cutoff ultramicropores for superior hydrogen separation.

Nat Commun 2021 01 11;12(1):268. Epub 2021 Jan 11.

State Key Laboratory of Engines, School of Mechanical Engineering, and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, 300072, Tianjin, China.

Carbon molecular sieve (CMS) membranes with rigid and uniform pore structures are ideal candidates for high temperature- and pressure-demanded separations, such as hydrogen purification from the steam methane reforming process. Here, we report a facile and scalable method for the fabrication of cellulose-based asymmetric carbon hollow fiber membranes (CHFMs) with ultramicropores of 3-4 Å for superior H separation. The membrane fabrication process does not require complex pretreatments to avoid pore collapse before the carbonization of cellulose precursors. Read More

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January 2021

Surface properties of stationary phases with embedded polar group based on secondary interaction, zeta potential measurement and linear solvatation energy relationship studies.

J Chromatogr A 2021 Jan 27;1637:461853. Epub 2020 Dec 27.

Chair of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarin St., PL- 87-100 Toruń, Poland.

The chromatographic properties of six non-commercially available stationary phases with ester or phosphodiester functional groups embedded into alkyl chain were studied. Zeta potential values of stationary phases suspended in water, organic solvent and their mixtures were measured. Moreover, the selectivity coefficients were calculated on the basis of the retention factor for the test solutes. Read More

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January 2021

Arrays of Microscale Linear Ridges with Self-Cleaning Functionality for the Oxygen Evolution Reaction.

ACS Appl Mater Interfaces 2021 Jan 6;13(2):2399-2413. Epub 2021 Jan 6.

Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby, British Columbia V5A 1S6, Canada.

Gas management during electrocatalytic water splitting is vital for improving the efficiency of clean hydrogen production. The accumulation of gas bubbles on electrode surfaces prevents electrolyte access and passivates the electrochemically active surface area. Electrode morphologies are sought to assist in the removal of gas from surfaces to achieve higher reaction rates at operational voltages. Read More

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January 2021

High-throughput hydrogen deuterium exchange mass spectrometry (HDX-MS) coupled with subzero-temperature ultrahigh pressure liquid chromatography (UPLC) separation for complex sample analysis.

Anal Chim Acta 2021 Jan 21;1143:65-72. Epub 2020 Nov 21.

Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK, 73019, USA. Electronic address:

Hydrogen deuterium exchange coupled with mass spectrometry (HDX-MS) is a powerful technique for the characterization of protein dynamics and protein interactions. Recent technological developments in the HDX-MS field, such as sub-zero LC separations, large-scale data analysis tools, and efficient protein digestion methods, have allowed for the application of HDX-MS to the analysis of multi protein systems in addition to pure protein analysis. Still, high-throughput HDX-MS analysis of complex samples is not widespread because the co-elution of peptides combined with increased peak complexity after labeling makes peak de-convolution extremely difficult. Read More

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January 2021

Characterizing Olefin Selectivity and Stability of Silver Salts in Ionic Liquids Using Inverse Gas Chromatography.

ACS Omega 2020 Dec 23;5(48):31362-31369. Epub 2020 Nov 23.

Ames Laboratory-USDOE and Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States.

Separation systems utilizing silver(I) ion-olefin complexation have limitations since silver(I) ions can be poisoned or reduced to metallic silver. Ionic liquids (ILs) are used as solvents for silver(I) ions to facilitate separations since their physico-chemical properties can be easily tuned. To develop separation systems with sustainable olefin selectivity, factors that affect silver(I) ion stability need to be understood. Read More

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December 2020

Deep eutectic solvents in separations: Methods of preparation, polarity, and applications in extractions and capillary electrochromatography.

J Chromatogr A 2020 Dec 11;1633:461613. Epub 2020 Oct 11.

Ames Laboratory-USDOE and Department of Chemistry, Iowa State University, Ames, IA 50011, USA. Electronic address:

Deep eutectic solvents (DESs) have emerged as alternatives to conventional organic solvents and ionic liquids (ILs). Their tunable and designer physio-chemical properties, low cost, and ease of preparation make them attractive solvent systems for use in extractions and additives to chromatographic separations. However, due to the diverse range of hydrogen bond acceptors and donors that comprise DESs, choosing the appropriate solvent for separations can be challenging. Read More

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December 2020

Hydrophobic functional liquids based on trioctylphosphine oxide (TOPO) and carboxylic acids.

Phys Chem Chem Phys 2020 Nov 27;22(42):24744-24763. Epub 2020 Oct 27.

The QUILL Research Centre, School of Chemistry and Chemical Engineering, Queen's University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK.

Trioctylphosphine oxide (TOPO) is a hydrophobic extracting agent used in a number of commercially important separations of valuable solutes from aqueous streams (with examples ranging from lanthanides, through gallium, to carboxylic acids). TOPO is traditionally used as a solute in kerosene, its extraction efficiency limited by its solubility in the organic diluents. In this work, eighteen hydrogen bond donors (HBDs) were screened for their capacity to liquefy TOPO, employing strategies used to design deep eutectic solvents (DES). Read More

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November 2020

Gas-sieving zeolitic membranes fabricated by condensation of precursor nanosheets.

Nat Mater 2021 Mar 5;20(3):362-369. Epub 2020 Oct 5.

Laboratory of Advanced Separations (LAS), École Polytechnique Fédérale de Lausanne (EPFL), Sion, Switzerland.

The synthesis of molecular-sieving zeolitic membranes by the assembly of building blocks, avoiding the hydrothermal treatment, is highly desired to improve reproducibility and scalability. Here we report exfoliation of the sodalite precursor RUB-15 into crystalline 0.8-nm-thick nanosheets, that host hydrogen-sieving six-membered rings (6-MRs) of SiO tetrahedra. Read More

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Quantum effects and H NMR chemical shifts of a bifurcated short hydrogen bond.

J Chem Phys 2020 Sep;153(11):114301

Department of Chemistry and Chemical Biology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey 08854, USA.

The monoprotonated compound N,N',N''-tris(p-tolyl)azacalix[3](2,6)pyridine (TAPH) contains an intramolecular hydrogen bond that is formed from three N atoms in its cavity. Constrained by the macrocyclic molecular structure, the separations between the N atoms in this bifurcated hydrogen bond are about 2.6 Å, considerably shorter than those typically observed for hydrogen bonded systems in the condensed phases. Read More

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September 2020

Key Applications and Potential Limitations of Ionic Liquid Membranes in the Gas Separation Process of CO, CH, N, H or Mixtures of These Gases from Various Gas Streams.

Molecules 2020 Sep 18;25(18). Epub 2020 Sep 18.

Center for Advanced Materials, Qatar University, Doha P.O. Box 2713, Qatar.

Heightened levels of carbon dioxide (CO) and other greenhouse gases (GHGs) have prompted research into techniques for their capture and separation, including membrane separation, chemical looping, and cryogenic distillation. Ionic liquids, due to their negligible vapour pressure, thermal stability, and broad electrochemical stability have expanded their application in gas separations. This work provides an overview of the recent developments and applications of ionic liquid membranes (ILMs) for gas separation by focusing on the separation of carbon dioxide (CO), methane (CH), nitrogen (N), hydrogen (H) or mixtures of these gases from various gas streams. Read More

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September 2020

A Polymorphic Azobenzene Cage for Energy-Efficient and Highly Selective p-Xylene Separation.

Angew Chem Int Ed Engl 2020 Nov 2;59(48):21367-21371. Epub 2020 Oct 2.

Smart Hybrid Materials (SHMs) Laboratory, Advanced Membranes and Porous Materials Center, Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.

Developing the competence of molecular sorbents for energy-saving applications, such as C8 separations, requires efficient, stable, scalable, and easily recyclable materials that can readily transition to commercial implementation. Herein, we report an azobenzene-based cage for the selective separation of p-xylene isomer across a range of C8 isomers in both vapor and liquid states with selectivity that is higher than the reported all-organic sorbents. The crystal structure shows non-porous cages that are separated by p-xylene molecules through selective CH-π interactions between the azo bonds and the methyl hydrogen atoms of the xylene molecules. Read More

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November 2020

Glycine-modified organic polymer monolith featuring zwitterionic functionalities for hydrophilic capillary electrochromatography.

J Chromatogr A 2020 Oct 19;1629:461497. Epub 2020 Aug 19.

Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Hubei Province Engineering and Technology Research Center for Fluorinated Pharmaceuticals, and Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China; State Key Laboratory of Transducer Technology, Chinese Academy of Sciences, Beijing 10080, China. Electronic address:

Allylglycine, a conventional amino acid derivative, possesses typical zwitterionic and hydrophilic functionalities deriving from the carboxyl and amino groups in its structure. A novel monolithic column poly(allylglycine-co-1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine) (AGly-co-TAT) with powerful hydrophilic selectivity and obvious zwitterionic feature was synthesized successfully with the monomer allyglycine and the cross-linker 1, 3, 5-triacryloylhexahydro-1, 3, 5-triazine through in-situ copolymerization for capillary electrochromatography. The obtained monolithic column has good permeability. Read More

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October 2020

Development of an Online 2D Ultrahigh-Pressure Nano-LC System for High-pH and Low-pH Reversed Phase Separation in Top-Down Proteomics.

Anal Chem 2020 10 1;92(19):12774-12777. Epub 2020 Sep 1.

Department of Chemistry and Biochemistry, University of Oklahoma, 101 Stephenson Parkway, Norman, Oklahoma 73019, United States.

The development of novel high-resolution separation techniques is crucial for advancing the complex sample analysis necessary for high-throughput top-down proteomics. Recently, our group developed an offline 2D high-pH RPLC/low-pH RPLC separation method and demonstrated good orthogonality between these two RPLC formats. Specifically, ultrahigh-pressure long capillary column RPLC separation has been applied as the second dimensional low-pH RPLC separation for the improvement of separation resolution. Read More

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October 2020

Single isomer cyclodextrins as chiral selectors in capillary electrophoresis.

J Chromatogr A 2020 Sep 5;1627:461375. Epub 2020 Jul 5.

Department of Pharmacognosy, Semmelweis University, Budapest, H-1085 Üllői út 26, Hungary. Electronic address:

Since decades, cyclodextrins are one of the most powerful selectors in chiral capillary electrophoresis for the enantioseparation of diverse organic compounds. This review concerns papers published over the last decade (from 2009 until nowadays), dealing with the capillary electrophoretic application of single isomer cyclodextrin derivatives in chiral separations. Following a brief overview of their synthetic approaches, the inventory of the neutral, negatively and positively charged (including both permanently ionic and pH-tunable ionizable substituents) and zwitterionic CD derivatives is presented, with insights to underlying structural aspects by NMR spectroscopy and molecular modeling. Read More

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September 2020

Impact of the column on effluent pH in cation exchange pH gradient chromatography, a practical study.

J Chromatogr A 2020 Aug 17;1626:461350. Epub 2020 Jun 17.

Institute of Pharmaceutical Sciences of Western Switzerland, University of Geneva, CMU-Rue Michel Servet 1, 1211 Geneva 4, Switzerland. Electronic address:

In ionexchange chromatography, the pH gradient mode becomes more and more popular today for the analysis of therapeutic proteins as this mode can provide higher or alternative selectivity to the commonly used salt gradient mode. Ideally, a linear pH response is expected when performing linear gradients. However up to now, only a very few buffer systems have been developed and are commercially available which can perform nearly linear pH responses when flowing through a given column. Read More

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Microporous polymer microspheres with amphoteric character for the solid-phase extraction of acidic and basic analytes.

J Chromatogr A 2020 Aug 16;1626:461348. Epub 2020 Jun 16.

Department of Analytical Chemistry and Organic Chemistry, Universitat Rovira I Virgili, Sescelades Campus, Marcel•lí Domingo s/n, 43007 Tarragona, Spain.

Solid-phase extraction (SPE) is a widely-used and very well-established sample preparation technique for liquid samples. An area of on-going focus for innovation in this field concerns the development of new and improved SPE sorbents that can enhance the sensitivity and/or the selectivity of SPE processes. In this context, mixed-mode ion-exchange sorbents have been developed and commercialised, thereby allowing enhanced capacity and selectivity to be offered by one single material. Read More

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Small lightning flashes from shallow electrical storms on Jupiter.

Nature 2020 08 5;584(7819):55-58. Epub 2020 Aug 5.

School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, GA, USA.

Lightning flashes have been observed by a number of missions that visited or flew by Jupiter over the past several decades. Imagery led to a flash rate estimate of about 4 × 10 flashes per square kilometre per year (refs. ). Read More

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Cellulose-Based Carbon Molecular Sieve Membranes for Gas Separation: A Review.

Molecules 2020 Aug 1;25(15). Epub 2020 Aug 1.

LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.

In the field of gas separation and purification, membrane technologies compete with conventional purification processes on the basis of technical, economic and environmental factors. In this context, there is a growing interest in the development of carbon molecular sieve membranes (CMSM) due to their higher permeability and selectivity and higher stability in corrosive and high temperature environments. However, the industrial use of CMSM has been thus far hindered mostly by their relative instability in the presence of water vapor, present in a large number of process streams, as well as by the high cost of polymeric precursors such as polyimide. Read More

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Method for evaluation of ionic interactions in liquid chromatography.

J Chromatogr A 2020 Aug 3;1625:461301. Epub 2020 Jun 3.

Waters Corporation, 34 Maple Street, Milford, MA 01757, USA. Electronic address:

In this work we utilized basic and acidic analytes to investigate the ionic interaction participation in retention behavior of selected reversed-phase and polar columns. The test analytes included nitrate, benzenesulfonate and trimethylphenylammonium ions. The fully aqueous mobile phase comprising 10 mM dichloroacetic acid buffered with ammonia solution to desirable pH was used for retention experiments. Read More

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Molecular Dynamics Insights and Water Stability of Hydrophobic Deep Eutectic Solvents Aided Extraction of Nitenpyram from an Aqueous Environment.

J Phys Chem B 2020 08 17;124(34):7405-7420. Epub 2020 Aug 17.

Department of Chemical Engineering, Indian Institute of Technology Guwahati Guwahati-781039, Assam, India.

In recent times, deep eutectic solvents (DES) have received attention as an extractive media for separations. In this work, the water stability of eight menthol-based DESs and two tetrabutylammonium chloride (NCl) based DESs with organic acid-based hydrogen bond donors (HBD) at a temperature of 298.15 K and atmospheric pressure were studied. Read More

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2,2'-(Disulfanedi-yl)di-benzoic acid ,-di-methyl-formamide monosolvate: crystal structure, Hirshfeld surface analysis and computational study.

Acta Crystallogr E Crystallogr Commun 2020 Jul 26;76(Pt 7):1150-1157. Epub 2020 Jun 26.

Research Centre for Crystalline Materials, School of Science and Technology, Sunway University, 47500 Bandar Sunway, Selangor Darul Ehsan, Malaysia.

The title 1:1 solvate, CHOS·CHNO, features a twisted mol-ecule of 2,2'-di-thiodi-benzoic acid (DTBA), with the central C-S-S-C torsion angle being -88.57 (6)°, and a mol-ecule of di-methyl-formamide (DMF). The carb-oxy-lic acid groups are, respectively, close to co-planar and twisted with respect to the benzene rings to which they are connected as seen in the CO/C torsion angles of 1. Read More

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Development of Thin-Film Composite Membranes from Aromatic Cardo-Type Co-Polyimide for Mixed and Sour Gas Separations from Natural Gas.

Glob Chall 2020 Jul 12;4(7):1900107. Epub 2020 Mar 12.

Research & Development Center Saudi Aramco P.O. Box 62 Dhahran 31311 Saudi Arabia.

The consumption of natural gas (NG) is rapidly increasing worldwide as it is becoming the second largest fuel source after coal. However, many of the world gas reserves contain high levels of subquality NG including the presence of carbon dioxide (CO), hydrogen sulfide (HS), nitrogen (N), benzene/toluene/xylene (BTX) etc., in varying amounts (up to 50% v/v in some reserves), which constitute several problems. Read More

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High-Voltage Paper Electrophoresis (HVPE).

Stephen C Fry

Methods Mol Biol 2020 ;2149:1-31

The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh, UK.

HVPE is an excellent and often overlooked method for obtaining objective and meaningful information about cell-wall "building blocks" and their metabolic precursors. It provides not only a means of analysis of known compounds but also an insight into the charge and/or mass of any unfamiliar compounds that may be encountered. It can be used preparatively or analytically. Read More

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