Gas permeation processes in biogas upgrading: A short review

Biogas upgrading is a widely studied and discussed topic. Many different technologies have been employed to obtain biomethane from biogas. Methods like water scrubbing or pressure swing adsorption are commonly used and can be declared as well established. Membrane gas permeation found its place among the biogas upgrading methods some years ago. Here, we try to summarize the progress in the implementation of gas permeation in biogas upgrading. Gas permeation has been already accepted as a commercially feasible method for CO₂ removal. Many different membranes and membrane modules have been tested and also some commercial devices are available. On the other hand, utilization of gas permeation in other steps of biogas upgrading like desulfurization, drying, or VOC removal is still rather rare. This review shows that membrane gas permeation is able to compete with classical biogas upgrading methods and tries to point out the main challenges of the research.     

6-Iodo-2-isopropyl-4H-3,1-benzoxazin-4-one as building block in heterocyclic synthesis

As a part of ongoing studies in the synthesis of a variety of heterocycles of biological importance, we report here an efficient and convenient method for the synthesis of novel compounds from 6-iodo-2-isopropyl-4H-3,1-benzoxazin-4-one 1 as building block. The reaction of benzoxazinone 1 with various reagents such as diethylmalonate, sodium azide, and phosphorus pentasulfide yielded the compounds 2–5. The behavior of benzothiazin-4-thione 5 toward formamide and hydrazine hydrate was investigated, forming the compounds 6 and 7. The reaction of quinazolinone derivative 8 with β-D-glucose pentaacetate, ethyl 2-methyl-5-((1S,2R,3R)-1,2,3,4-tetrahydroxybutyl)furan-3-carboxylate, epichlorohydrin and benzenesulphonyl chloride afforded quinazolinone derivatives 9, 10, 12, and 13 respectively. The reaction of quinazolinone derivative 10 with acetic anhydride resulted in formation of the acylated compound 11. The behavior of quinazolinylacetohydrazide derivative 14 toward carbon electrophiles^[16 El-Hashash, M. A.; El-Naggar, A. M.; El-Bordany, E. A.; Marzouk, M. I.; Nawar, T. M. S. Regioselectivity and regiospecificity of benzoxazinone (2-isopropyl4H-3,1-benzoxazinone) derivatives toward nitrogen nucleophiles and evaluation of antimicrobial activity. Synth. Commun. 2016, 46(14), 1230–1241.[Taylor & Francis Online], [Web of Science ®] , [Google Scholar]^] has been investigated by its reaction with ethyl benzoylacetate, potassium thiocyanate, and phenyl isothiocyanate, affording the quinazolinone derivatives 15, 16, and 18, respectively. Treatment of compound 16 with sodium hydroxide followed by hydrochloric acid yielded the mercapto-triazole derivative 17. The structures of the newly synthesized compounds were confirmed by elemental analysis, infrared (IR), ¹H NMR, ¹³C NMR, and mass spectra. The antimicrobial activities of some of the synthesized compounds were preliminarily evaluated.     

Studies on transition metal murexide complexes

Iron, cobalt, nickel, copper, zinc, cadmium and mercury murexide complexes have been prepared and characterized. The thermal properties of these complexes are studied deeply by DTA technique where their thermal peaks are explained. The multi-stages thermal decomposition mechanism is proposed. The thermodynamic parameters of the decomposition steps are calculated. The entropy change values for all complexes are of the same magnitude and all transition states of the thermal reactions are more ordered than the reactants. The thermal reactions proceed in complicated mechanisms. The fractions appeared in the calculated orders of the thermal reactions confirmed that these reactions proceeded via complex mechanisms.     

New polyethyleneglycol-functionalized texaphyrins: synthesis and in vitro biological studies

The synthesis of four new analogues of motexafin gadolinium (MGd), a gadolinium(III) texaphyrin complex in clinical trials for its anticancer properties, is described. These new derivatives contain either 1,2-diaminobenzene or 2,3-diaminonaphthalene subunits as the source of the imine nitrogens and bear multiple 2-[2-(2-methoxyethoxy)ethoxy]ethoxy (PEG) groups, on either meso aryl or beta-pyrrolic substituents, to increase their water solubility. All four analogues were found to be more active in vitro than the parent system MGd as judged from cell proliferation assays using the PC3 and A549 cell lines.     

Sulfito- und Thiosulfato-Komplexe des Kobalts(III) mitα-Benzildioxim Überα-Dioximinkomplexe der Übergangsmetalle, 52. Mitt.

Some new ligand exchange reactions of [Co(diph·H)₂Cl(H₂O)] and [Co(diph·H)₂(SO₃)(H₂O)]^– complexes with N₃ ^–, S₂O₃ ^2– and with aromatic and heterocyclic amines were carried out. A series of derivatives of the types [Co(diph·H)₂(SO₃)X] ^n– (X=N₃ ^–, S₂O₃ ^2– oramine) and [Co(diph·H)₂(S₂O₃)₂]^3– were described and characterized. Some structural problems are resolved and discussed on the basis of UV and IR spectral data.     

Mössbauer and XRD study of pulse plated Fe–P and Fe–Ni thin layers

⁵⁷Fe conversion electron Mössbauer spectroscopy, X-ray diffraction, electrochemical and magnetic measurements were used to study pulse electroplated Fe–P and Ni–Fe coatings. XRD and ⁵⁷Fe CEMS measurements revealed the amorphous character of the novel pulse plated Fe–P alloys. CEM spectra indicated significant differences in the short range order and in the magnetic anisotropy between the Fe–P deposits pulse plated at medium long deposition time (t _on?=?2 ms), with short relaxation time (t _off?=?9 ms) and low current density (I _p?=?0.05 Acm^?2) or at short deposition time (t _on?=?1 ms) with long relaxation time (t _off?=?250 ms) and high current density (I _p?=?1.0 Acm^?2). The broad peaks centred around the fcc reflections in XRD of the pulse plated Ni-22 wt.% Fe deposit reflected a microcrystalline Ni–Fe alloy with a very fine, 5–8 nm, grain size. The CEM spectrum of the pulse plated Ni-22 wt.% Fe coating corresponded to a highly disordered solid solution alloy containing a minute amount of ferrihydrite. Extreme favourable soft magnetic properties were observed with these Ni–Fe and Fe–P pulse plated thin layers.     

New 1,2,3-Triazole-Coumarin-Glycoside Hybrids and Their 1,2,4-Triazolyl Thioglycoside Analogs Targeting Mitochondria Apoptotic Pathway: Synthesis,Anticancer Activity and Docking Simulation

Toxicity and resistance to newly synthesized anticancer drugs represent a challenging phenomenon of intensified concern arising from variation in drug targets and consequently the prevalence of the latter concern requires further research. The current research reports the design, synthesis, and anticancer activity of new 1,2,3-triazole-coumarin-glycosyl hybrids and their 1,2,4-triazole thioglycosides as well as acyclic analogs. The cytotoxic activity of the synthesized products was studied against a panel of human cancer cell lines. Compounds 8, 10, 16 and 21 resulted in higher activities against different human cancer cells. The impact of the hybrid derivative 10 upon different apoptotic protein markers, including cytochrome c, Bcl-2, Bax, and caspase-7 along with its effect on the cell cycle was investigated. It revealed a mitochondria-apoptotic effect on MCF-7 cells and had the ability to upregulate pro-apoptotic Bax protein and downregulate anti-apoptotic Bcl-2 protein and thus implies the apoptotic fate of the cells. Furthermore, the inhibitory activities against EGFR, VEGFR-2 and CDK-2/cyclin A2 kinases for 8, 10 and 21 were studied to detect the mechanism of their high potency. The coumarin-triazole-glycosyl hybrids 8 and 10 illustrated excellent broad inhibitory activity (IC₅₀= 0.22 ± 0.01, 0.93 ± 0.42 and 0.24 ± 0.20 μM, respectively, for compound 8), (IC₅₀ = 0.12 ± 0.50, 0.79 ± 0.14 and 0.15± 0. 60 μM, respectively, for compound 10), in comparison with the reference drugs, erlotinib, sorafenib and roscovitine (IC₅₀ = 0.18 ± 0.05, 1.58 ± 0.11 and 0.46 ± 0.30 μM, respectively). In addition, the docking study was simulated to afford better rationalization and put insight into the binding affinity between the promising derivatives and their targeted enzymes and that might be used as an optimum lead for further modification in the anticancer field.     

Redox-Neutral Metal-Free Three-Component Carbonylative Dearomatization of Pyridine Derivatives with CO2

The TBD (1,3,5-triazabicyclodec-5-ene) assisted three-component carbonylation of pyridine-2-methanamines is documented by means of CO₂ as a benign CO surrogate. The redox-neutral methodology enables the realization of densely functionalized imidazo-pyridinones in high yields (up to 93 %) and excellent chemoselectivity. Combined computational and experimental investigations revealed an unprecedented RCOCl/TBD concerted electrophilic activation of carbon dioxide.     

Design,Synthesis, and Evaluation of Some Novel Heterocycles Bearing Pyrazole Moiety as Potential Anticancer Agents

1,3‐Diphenylpyrazole‐4‐carboxylaldehyde and o‐hydroxyacetophenone were exploited as starting materials for the synthesis of novel substituted chalconated pyrazole derivative. The proclivity of this compound towards carbon and nitrogen nucleophiles such as malononitrile, diethyl malonate, ethyl cyanoacetate, ethyl acetoacetate, semicarbazide, thiosemicarbazide, and hydroxylamine has been investigated. The structures of all synthesized compounds were ascertained by analytical and spectral data. The antitumor activity of the target synthesized compounds was tested against a panel of two human tumor cell lines, namely, hepatocellular carcinoma (liver) HepG2 and mammary gland breast MCF‐7.     

Development of a differential pulse voltammetric method for the determination of Silymarin/Vitamin E acetate mixture in pharmaceuticals

Differential pulse voltammetric method was developed for determination of Silymarin (SMR)/Vitamin E acetate (VEA) mixture in pharmaceuticals. SMR and VE gave well-resolved diffusion-controlled anodic peaks at +756 and +444mV, respectively (versus Ag/AgCl) in Britton-Robinson buffer at pH 2.8. The solution conditions and instrumental parameters were optimized for their quantitative determination. The linear response was obtained in the range 0.1-4.0mgL(-1) with a detection limit of 0.03mgL(-1) for SMR and 0.05-4.0mgL(-1) with a detection limit of 0.01mgL(-1)for VEA.