scholarly journals A DEVELOPMENT OF AN EFFECTIVE METHOD FOR THE SYNTHESIS OF 2-(5-OXO-4,5-DIHYDRO-1,2,4-OXADIAZOL-3-YL)BENZOIC ACID

2020 ◽  
pp. 51-54
Author(s):  
V. Tkachuk ◽  
T. Lyubchuk ◽  
T. Tkachuk ◽  
O. Hordiyenko
Keyword(s):  
Benzoic Acid ◽  
Room Temperature ◽  
Total Yield ◽  
Partial Hydrolysis ◽  
Diethyl Carbonate ◽  
Aromatic Acids ◽  
Sodium Ethylate ◽  
Anhydrous Ethyl Acetate ◽  
Naoh Solution ◽  
Related Compounds

2-(5-Oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was synthesized using a new effective method – thermal heterocyclization of 3-(hydroxyimino)isoindolin-1-one, which occurs as a result of its interaction with 1,1'-carbonyldiimidazole (CDI) and subsequent base-promoted cycleopening of the obtained intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione. Direct cyclization of 3-(hydroxyimino)isoindolin-1-one by the reaction with diethyl carbonate in the presence of sodium ethylate in ethanol at room temperature and under heating was unsuccessful. The same result was observed when using triphosgene in the presence of triethylamine in dichloromethane. Treating 3-(hydroxyimino)isoindolin-1-one with methyl chloroformate gave 3-(((methoxycarbonyl)oxy)-imino)isoindolin-1-one which was thermally stable and was not cyclized into the desired acid by boiling in toluene and o-xylene for 24 hours. The reflux of the excess of CDI with 3-(hydroxyimino)isoindolin-1-one in anhydrous ethyl acetate and subsequent alkaline hydrolysis gave the desired 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid in a total yield of 90%. An attempt to stop the process at the stage of formation of the intermediate 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione by carrying out the reaction in the absence of a base failed. Its partial hydrolysis took place during the reaction, and especially at the stage of isolation, and as a result a mixture of 3H,5H-[1,2,4]oxadiazolo[3,4-a]isoindole-3,5-dione and 2-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)benzoic acid was formed in a ratio of about 2:3. The obtained substance after mixing with aqueousmethanolic NaOH solution and subsequent acidification with 1M HCl was quantitatively converted into the pure desired acid. The developed method allows the use of 3-(hydroxyimino)isoindolin-1-ones as convenient starting materials for the preparation of vic-(5-oxo-4,5-dihydro-1,2,4-oxadiazol-3-yl)aromatic acids and subsequently related compounds, in particular isomeric vic-carbamimidoyl(hetero)aromatic carboxylic acids, which cannot be obtained by other currently known methods. All the compounds obtained during the development of the method were studied by means of NMR spectroscopy.

Intrinsic doping limit and defect-assisted luminescence in Cs4PbBr6

2019 ◽  
Author(s):  
Young-Kwang Jung ◽  
Joaquin Calbo ◽  
Ji-Sang Park ◽  
Lucy D. Wahlley ◽  
Sunghyun Kim ◽  
...  
Keyword(s):  
First Principles ◽  
Room Temperature ◽  
Stokes Shift ◽  
Green Luminescence ◽  
Counter Ions ◽  
Self Consistent ◽  
Deep Ultraviolet ◽  
Halide Perovskite ◽  
Related Compounds ◽  
Level Analysis

Cs<sub>4</sub>PbBr<sub>6 </sub>is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr<sub>6</sub><sup>4-</sup> octahedra with Cs<sup>+</sup> counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs<sub>4</sub>PbBr<sub>6</sub>. We find a heavily compensated system where the room-temperature carrier concentrations (< 10<sup>9</sup> cm<sup>-3</sup>) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br<sub>3</sub>) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission. <br>

Intrinsic doping limit and defect-assisted luminescence in Cs4PbBr6

2019 ◽  
Author(s):  
Young-Kwang Jung ◽  
Joaquin Calbo ◽  
Ji-Sang Park ◽  
Lucy D. Wahlley ◽  
Sunghyun Kim ◽  
...  
Keyword(s):  
First Principles ◽  
Room Temperature ◽  
Stokes Shift ◽  
Green Luminescence ◽  
Counter Ions ◽  
Self Consistent ◽  
Deep Ultraviolet ◽  
Halide Perovskite ◽  
Related Compounds ◽  
Level Analysis

Cs<sub>4</sub>PbBr<sub>6 </sub>is a member of the halide perovskite family that is built from isolated (zero-dimensional) PbBr<sub>6</sub><sup>4-</sup> octahedra with Cs<sup>+</sup> counter ions. The material exhibits anomalous optoelectronic properties: optical absorption and weak emission in the deep ultraviolet (310 - 375 nm) with efficient luminescence in the green region (~ 540 nm). Several hypotheses have been proposed to explain the giant Stokes shift including: (i) phase impurities; (ii) self-trapped exciton; (iii) defect emission. We explore, using first-principles theory and self-consistent Fermi level analysis, the unusual defect chemistry and physics of Cs<sub>4</sub>PbBr<sub>6</sub>. We find a heavily compensated system where the room-temperature carrier concentrations (< 10<sup>9</sup> cm<sup>-3</sup>) are more than one million times lower than the defect concentrations. We show that the low-energy Br-on-Cs antisite results in the formation of a polybromide (Br<sub>3</sub>) species that can exist in a range of charge states. We further demonstrate from excited-state calculations that tribromide moieties are photoresponsive and can contribute to the observed green luminescence. Photoactivity of polyhalide molecules is expected to be present in other halide perovskite-related compounds where they can influence light absorption and emission. <br>

scholarly journals Effect of Olive-Pine Bottom Ash on Properties of Geopolymers Based on Metakaolin

2019 ◽  
Author(s):  
Eduardo Bonet-Martínez ◽  
Pedro García-Cobo ◽  
Luis Pérez-Villarejo ◽  
Eulogio Castro ◽  
Dolores Eliche-Quesada
Keyword(s):  
Room Temperature ◽  
Bottom Ash ◽  
Raw Material ◽  
Climatic Chamber ◽  
General Terms ◽  
Saturated Atmosphere ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Water Saturated ◽  
Potential Use

In this research, the feasibility of using bottom ashes generated by the combustion of biomass (olive pruning and pine pruning) as a source of aluminosilicates (OPBA) has been studied, replacing the metakaolin precursor (MK) in different proportions (0, 25, 50, 75 and 100 wt. % substitution) for the synthesis of geopolymers. As alkaline activator an 8 M NaOH solution and a Na2SiO3 have been used. The geopolymers were cured 24 hours in a climatic chamber at 60 &deg; C in a water-saturated atmosphere, subsequently demoulded and cured at room temperature for 28 days. The results indicated that the incorporation of OPBA waste, which have 19.7 wt. % of Ca, modifies the characteristics of the products formed after alkaline activation. In general terms, the incorporation of increasing amounts of calcium-rich ashes results in geopolymers with higher bulk density. The compressive strength increases with the addition of up to 50 wt. % of OPBA with respect to the control geopolymers, contributing the composition of the residue to the acquisition of a better behaviour mechanical. The results indicate the potential use of these OPBA waste as raw material to produce unconventional cements with 28-day curing strengths greater than 10 MPa, and thermal conductivities less than 0.35 W/mK.

Effect of Corrosive Medium on the Corrosion Resistance of FeCrMoCB Amorphous Alloy Coating

2011 ◽  
Vol 291-294 ◽  
pp. 65-71 ◽  
Author(s):  
Qing Jun Chen ◽  
Lin Li Hu ◽  
Xian Liang Zhou ◽  
Xiao Zhen Hua ◽  
Ying Jun Yang
Keyword(s):  
Corrosion Resistance ◽  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Equivalent Circuit Model ◽  
Alloy Coating ◽  
Potentiodynamic Polarization Curves ◽  
Naoh Solution ◽  
Oxygen Fuel

The purpose of this study is to investigate the electrochemical properties of Fe44Cr16Mo16C18B6amorphous alloy coating fabricated using high velocity oxygen fuel (HVOF) technology in 2.0M HCl and NaOH solution at room temperature(25°C). Based on the potentiodynamic polarization curves and Electrochemical Impedance Spectroscopy(EIS) testing results of coating in aqueous solutions of HCl and NaOH, the corrosion resistance of Fe44Cr16Mo16C18B6amorphous alloy coating in HCl solution was superior to that in NaOH solution. The icorrwas 1.487×10-5A·cm-2in HClsolution and 1.107×10-4A·cm-2in NaOH solution, while the Rtreach to 5.789×104Ω·cm2and 9780Ω·cm2, respectively. On the other hand, these corrosion phenomenon could be better interpreted by R(Q(R(RQW)))(RL) and R(RL)(Q(R(CW))) equivalent circuit model, which were different from that of other Fe-based amorphous alloys in HCl and NaOH solution, respectively.

Synthesis and Crystal Structure of a Cadmium(II) Complex with 2-(4΄-Chlorine-Benzoyl)-Benzoic Acid and 1,10-Phenanthroline

2011 ◽  
Vol 339 ◽  
pp. 313-316
Author(s):  
Xiu Mei Li ◽  
Zhi Tao Wang ◽  
Qing Wei Wang
Keyword(s):  
Benzoic Acid ◽  
Room Temperature ◽  
Supramolecular Network ◽  
X Ray Diffraction ◽  
Organic Complex ◽  
Orthorhombic Space Group ◽  
Synthesis And Crystal Structure ◽  
X Ray ◽  
Metal Organic Complex ◽  
Metal Organic

A new metal-organic complex Cd2(cbba)4(phen)2 (Hcbba = 2-(4΄-chlorine-benzoyl)- benzoic acid, phen = 1,10-phenanthroline) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, fluorescence spectrum and single-crystal X-ray diffraction. The compound crystallizes in orthorhombic, space group Pbcn with a = 12.0976(4), b = 18.0925(6), c = 31.6829(10) Å, V = 6934.6(4) Å3, C80H48Cd2Cl4N4O12, Mr = 1623.82, Dc = 1.555 g/cm3, μ(MoKα) = 0.8365 mm1, F(000) = 3264, Z = 4, the final R = 0.0396 and wR = 0.0960 for 5372 observed reflections (I > 2(I)). It exhibits a 3D supramolecular network through π-π interactions and shows green luminescent property at room temperature.

ChemInform Abstract: New Aspects of the Chemistry of 2,4,6-Tris(trifluoromethyl)benzoic Acid and Related Compounds.

ChemInform ◽  
2010 ◽  
Vol 23 (3) ◽  
pp. no-no
Author(s):  
R. FILLER ◽  
W. K. GNANDT ◽  
W. CHEN ◽  
S. LIN
Keyword(s):  
Benzoic Acid ◽  
Related Compounds

scholarly journals An Isocratic Reversed-Phase High-Performance Liquid Chromatographic Method for the Simultaneous Determination of Benzoyl Peroxide and the Related Compounds Benzoic Acid, Benzaldehyde, Ethyl Benzoate, Methylparaben, and Propylparaben in Dermal Preparations

2008 ◽  
Vol 91 (5) ◽  
pp. 1025-1036 ◽  
Author(s):  
Mohammed Shahid Ali ◽  
Syed Rafiuddin ◽  
Muhammad Imran Munir ◽  
Mohsin Ghori ◽  
Aamer Roshanali Khatri
Keyword(s):  
Benzoic Acid ◽  
High Performance ◽  
Chromatographic Method ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Ethyl Benzoate ◽  
Liquid Chromatographic Method ◽  
Liquid Chromatographic ◽  
Related Compounds

Abstract A reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of benzoyl peroxide and the related compounds benzoic acid (BA), methylparaben, benzaldehyde, propylparaben, and ethyl benzoate. The compounds are separated on a column containing octadecyl silane chemically bonded to porous silica particles. The mobile phase is acetonitrilebuffer (45 + 55, v/v). Solutions are injected into the chromatographic system under isocratic conditions at a constant flow rate of 1.5 mL/min with UV detection at 235 nm. Analysis of stability samples showed rapid accumulation of BA by thermal degradation. A rationale has been established for the acceptable limit of BA in the formulation, which already contains BA (0.2) as a preservative. The proposed method is efficient and determines the active compound and 5 related compounds in a run time of 20 min. The method was validated according to the guidelines of the International Conference on Harmonization and demonstrated good agreement with the validation requirements.

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