Pharmaceuticals degradation by UV and UV/H2O2 treatments

2002 ◽  
Vol 2 (2) ◽  
pp. 19-26 ◽  
Author(s):  
A. Bozzi ◽  
A. Lopez ◽  
G. Mascolo ◽  
G. Tiravanti
Keyword(s):  
Room Temperature ◽  
Parent Compound ◽  
Molar Ratio ◽  
Mercury Lamp ◽  
H2o2 Treatment ◽  
Carbon And Nitrogen ◽  
Thiadiazole Ring ◽  
Sequential Transformation ◽  
Pharmaceuticals Degradation ◽  
By Products

The degradation by UV and UV/H2O2 treatments of the pharmaceutical intermediate 5-methyl-1,3,4-thiadiazole-2-methylthiol (MMTD-Me) has been investigated and compared to that of its parent compound [5-methyl-1,3,4-thiadiazole-2-thiol (MMTD)] previously studied. The investigation has been carried out with a 17 W low pressure mercury lamp, at room temperature, with an initial MMTD-Me concentration of 1 mg/l and with a molar ratio H2O2/substrate of 100/1. The results show that: (i) the complete MMTD-Me removal is achieved within 60 and 20 minutes by UV and UV/H2O2 treatment respectively; (ii) the UV only irradiation does not cause any MMTD-Me mineralization; (iii) the UV/H2O2 treatment, after 4 hours, leads to a complete mineralization of MMTD-Me organic sulfur and to a partial mineralization of carbon and nitrogen (79 and 16% respectively). Degradation by-products identification, performed by HPLC-UV-MS, revealed that the UV only irradiation gives rise to the sequential transformation of MMTD-Me into two by-products one of which, the last one, accumulates in the solution. Conversely, the UV/H2O2 treatment leads to the formation of two intermediate by-products that undergo further degradation with the breakdown of the thiadiazole ring. These results confirm the effectiveness of UV based processes, alone or in combination with H2O2, in degrading pharmaceutical intermediates.

scholarly journals Calcium Phosphate Powder Synthesized from Calcium Acetate and Ammonium Hydrophosphate for Bioceramics Application

Ceramics ◽  
2018 ◽  
Vol 1 (2) ◽  
pp. 375-392 ◽  
Author(s):  
Tatiana Safronova ◽  
Valery Putlayev ◽  
Yaroslav Filippov ◽  
Tatiana Shatalova ◽  
Evgeny Karpushkin ◽  
...  
Keyword(s):  
Phase Composition ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Calcium Acetate ◽  
Molar Ratio ◽  
Composite Ceramics ◽  
Phosphate Powder ◽  
Starting Solution ◽  
By Products ◽  
Ammonium Hydrophosphate

Calcium phosphate powder was synthesized at room temperature from aqueous solutions of ammonium hydrophosphate and calcium acetate without pH adjusting at constant Ca/P molar ratio 1.5. Phase composition of the as-synthesized powder depended on the precursors concentration: At 2.0 M of calcium acetate in the starting solution, poorly crystallized hydroxyapatite was formed, 0.125 M solution of calcium acetate afforded brushite, and the powders synthesized from 0.25–1.0 M calcium acetate solutions were mixtures of the mentioned phases. Firing at 1100 °C led to complete elimination of the reaction by-products, yet the phase composition of the annealed compacted samples was the following: When 2.0 M solution of calcium acetate was used, the obtained ceramics consisted of β-Ca3(PO4)2, whereas at 0.125 to 1.0 M of calcium acetate, the ceramics was a mixture of β-Ca3(PO4)2 and β-Ca2P2O7. Synthesized calcium phosphate powders can be used as the powdered precursors for biocompatible bioresorbable composite ceramics production.

Synthese von Silicium-Phosphor-Ringen - Struktur eines cis-2.2.4.4-Tetrakis(silylamino)-1.3-diphospha-2.4-disilacyclobutans / Synthesis of Silicon-Phosphorus-Rings - Structure of a cis-2,2,4,4-Tetrakis(silylamino)-1,3-diphospha-2,4-disilacyclobutane

1983 ◽  
Vol 38 (12) ◽  
pp. 1557-1562 ◽  
Author(s):  
Uwe Klingebiel ◽  
Norbert Vater ◽  
William Clegg ◽  
Martin Haase ◽  
George M. Sheldrick
Keyword(s):  
Crystal Structure ◽  
Nmr Spectra ◽  
Room Temperature ◽  
Molar Ratio ◽  
Trans Isomers ◽  
Cis And Trans Isomers ◽  
Cis And Trans ◽  
By Products ◽  
Cis Isomer

Fluorosilylphosphanes of the type R2SiFPHR′ (R = CHMe2, CMe3, NMeSiMe3; R′ = H, C6H5; 1-4) are obtained in the reaction of difluorosilanes with lithiated phosphanes in a molar ratio 1:1. Diphosphasilanes (5, 6) and a difluorosilylphosphane (7) are isolated as by-products. 1-4 react with n-C4H9Li to give cyclic silylphosphanes, LiF, and C4H10 (8-11). Dilithiated 5 reacts with F2PN(CMe3)SiMe3 to form of a four-membered SiP3-ring 12. The 31P NMR spectra of 9 and 11 show signal coalescence for the cis-and trans-isomers at room temperature. The crystal structure of the cis-isomer of 11 has been determined. The substituted ring 13 is prepared in the reaction of lithiated 9 and Me2SiF2

scholarly journals Pure hydroxyapatite synthesis originating from amorphous calcium carbonate

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Michika Sawada ◽  
Kandi Sridhar ◽  
Yasuharu Kanda ◽  
Shinya Yamanaka
Keyword(s):  
Calcium Carbonate ◽  
Calcium Phosphate ◽  
Room Temperature ◽  
Molar Ratio ◽  
Final Phase ◽  
Amorphous Calcium Carbonate ◽  
Phosphate Compound ◽  
Synthesis Strategy ◽  
Phosphorylation Reaction ◽  
Subsequent Calcination

AbstractWe report a synthesis strategy for pure hydroxyapatite (HAp) using an amorphous calcium carbonate (ACC) colloid as the starting source. Room-temperature phosphorylation and subsequent calcination produce pure HAp via intermediate amorphous calcium phosphate (ACP). The pre-calcined sample undergoes a competitive transformation from ACC to ACP and crystalline calcium carbonate. The water content, ACC concentration, Ca/P molar ratio, and pH during the phosphorylation reaction play crucial roles in the final phase of the crystalline phosphate compound. Pure HAp is formed after ACP is transformed from ACC at a low concentration (1 wt%) of ACC colloid (1.71 < Ca/P < 1.88), whereas Ca/P = 1.51 leads to pure β-tricalcium phosphate. The ACP phases are precursors for calcium phosphate compounds and may determine the final crystalline phase.

scholarly journals Crystal structure of the new hybrid material bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate

2015 ◽  
Vol 71 (11) ◽  
pp. 1384-1387
Author(s):  
Marwen Chouri ◽  
Habib Boughzala
Keyword(s):  
Crystal Structure ◽  
Aqueous Solution ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Molar Ratio ◽  
Water Molecules ◽  
Site Symmetry ◽  
Two Dimensional ◽  
Slow Evaporation ◽  
Solution Ph

The title compound bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate, (C6H14N2)2[Bi2Cl10]·2H2O, was obtained by slow evaporation at room temperature of a hydrochloric aqueous solution (pH = 1) containing bismuth(III) nitrate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio. The structure displays a two-dimensional arrangement parallel to (100) of isolated [Bi2Cl10]4−bioctahedra (site symmetry -1) separated by layers of organic 1,4-diazoniabicyclo[2.2.2]octane dications [(DABCOH2)2+] and water molecules. O—H...Cl, N—H...O and N—H...Cl hydrogen bonds lead to additional cohesion of the structure.

Efficient synthesis of pyrido[2,3-d]pyrimidine-7-carboxylic acids catalyzed by a TiO2/SiO2 nanocomposite in aqueous media at room temperature

2018 ◽  
Vol 73 (9) ◽  
pp. 641-645 ◽  
Author(s):  
Sepehr Sadegh-Samiei ◽  
Shahrzad Abdolmohammadi
Keyword(s):  
Heterogeneous Catalyst ◽  
Carboxylic Acids ◽  
Room Temperature ◽  
Aqueous Media ◽  
Reaction Times ◽  
Molar Ratio ◽  
Efficient Synthesis ◽  
Reaction Conditions ◽  
Moderate Reaction ◽  
Recyclable Heterogeneous Catalyst

AbstractA novel and efficient synthesis of eight 5-aryl-1,3-dimethyl-2,4-dioxo-1,2,3,4,5,8-hexahydropyrido[2,3-d]pyrimidine-7-carboxylic acids using a TiO2/SiO2 nanocomposite with a molar ratio of 1:1 as a recyclable heterogeneous catalyst is described. The desired products, five of which are new, are formed in short reaction times (2–3 h) with high to excellent yields (94%–98%) under very moderate reaction conditions (room temperature, aqueous media).

scholarly journals Chemical Cleaning of Ultrafiltration Membrane Fouled by Humic Substances: Comparison between Hydrogen Peroxide and Sodium Hypochlorite

2019 ◽  
Vol 16 (14) ◽  
pp. 2568 ◽  
Author(s):  
Kai Li ◽  
Shu Li ◽  
Tinglin Huang ◽  
Chongzhe Dong ◽  
Jiawei Li ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Humic Substances ◽  
Sodium Hypochlorite ◽  
Alkaline Condition ◽  
Chemical Cleaning ◽  
H2o2 Treatment ◽  
Cleaning Agent ◽  
Cleaning Agents ◽  
Cleaning Efficacy ◽  
By Products

Chemical cleaning is indispensable for the sustainable operation of ultrafiltration (UF) system in water and wastewater treatment. Sodium hypochlorite (NaClO) is an established cleaning agent for membranes subject to organic and microbial fouling, but concerns have been raised about the generation of toxic halogenated by-products during NaClO cleaning. Hydrogen peroxide (H2O2) is a potential “green” cleaning agent that can avoid the formation of halogenated by-products. In this work, cleaning efficacy of H2O2 and NaClO for UF membrane fouled by humic substances (HS) was evaluated under a wide pH range, and change of HS’s properties due to reaction with cleaning agents was examined. The cleaning efficacy of H2O2 was lower than that of NaClO at pH 3–9, but it increased to a level (91.4%) comparable with that of NaClO at pH 11. The extents of changes in properties and fouling potential of HS due to reacting with cleaning agents were consistent with their cleaning efficacy. H2O2 treatment at pH 11 significantly increased negative charge of HS molecules, decomposed high-MW molecules, and reduced its fouling potential. Therefore, considering treatment/disposal of cleaning waste and cleaning efficacy, H2O2 cleaning under strong alkaline condition can be a good choice for HS-fouled membrane.

scholarly journals Initial Investigation into the Leaching of Manganese from Nodules at Room Temperature with the Use of Sulfuric Acid and the Addition of Foundry Slag—Part I

Minerals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 565 ◽  
Author(s):  
Norman Toro ◽  
Nelson Herrera ◽  
Jonathan Castillo ◽  
Cynthia Torres ◽  
Rossana Sepúlveda
Keyword(s):  
Particle Size ◽  
Sulfuric Acid ◽  
Acid Concentration ◽  
Room Temperature ◽  
Sulfuric Acid Concentration ◽  
Extraction Rate ◽  
Molar Ratio ◽  
Independent Variables ◽  
Initial Investigation ◽  
Optimization Methodology

In this study, the surface optimization methodology was used to assess the effect of three independent variables—time, particle size and sulfuric acid concentration—on Mn extraction from marine nodules during leaching with H2SO4 in the presence of foundry slag. The effect of the MnO2/Fe ratio and particle size (MnO2) was also investigated. The maximum Mn extraction rate was obtained when a MnO2 to Fe molar ratio of 0.5, 1 M of H2SO4, −320 + 400 Tyler mesh (−47 + 38 μm) nodule particle size and a leaching time of 30 min were used.

scholarly journals Synthesis, Characterization and Antifungal Studies of Adducts of p- Ethylphenyldithiocarbonates of Copper(II)

2019 ◽  
Vol 31 (8) ◽  
pp. 1819-1824
Author(s):  
Shivangi Sharma ◽  
Renu Sachar ◽  
G.D. Bajju ◽  
Vikas Sharma
Keyword(s):  
Magnetic Susceptibility ◽  
Electron Spin Resonance ◽  
Room Temperature ◽  
Molar Conductance ◽  
Octahedral Geometry ◽  
Molar Ratio ◽  
Spectral Studies ◽  
Distorted Octahedral Geometry ◽  
Distorted Octahedral ◽  
Spin Resonance

A series of adducts of p-ethylphenyldithiocarbonates of copper(II) [(p-C2H5C6H4OCS2)2Cu] with ethyl pyridines and chloro pyridines have been synthesized in 1:2 molar ratio. They were characterized by elemental analysis, magnetic susceptibility and molar conductance measurements, infrared, electronic, electron spin resonance and mass spectroscopy, NMR and thermogravimetric analysis. In addition, antifungal studies of these adducts were also performed. The results revealed that the adducts have 1:2 stoichiometry, non-electrolytic and paramagnetic at room temperature. On the basis of spectral studies, a distorted octahedral geometry is proposed around copper(II) ion. ESR studies depicted elongated axial symmetry of Cu(II)adducts with nitrogen donors. Moreover, the adducts also showed potential antifungal activity against Fusarium oxysporium.

scholarly journals Low-temperature transport properties of n-type layered homologous compounds Bi8−xSbxSe7

2020 ◽  
Vol 8 (40) ◽  
pp. 14037-14048
Author(s):  
Pavan Kumar-Ventrapati ◽  
Shantanu Misra ◽  
Gaëlle Delaizir ◽  
Anne Dauscher ◽  
Bertrand Lenoir ◽  
...  
Keyword(s):  
Low Temperature ◽  
Transport Properties ◽  
Thermoelectric Materials ◽  
Room Temperature ◽  
Parent Compound ◽  
New Class ◽  
Highly Efficient ◽  
Homologous Compounds

The n-type chalcogenide Bi8Se7 is the parent compound of a new class of highly-efficient thermoelectric materials for near-room-temperature thermoelectric applications.

Desulfurization from Gasoline by Polymer Resin at Room Temperature and Atmospheric Pressure

2011 ◽  
Vol 396-398 ◽  
pp. 1283-1286
Author(s):  
Jian Peng Zhu ◽  
Chun Hu Li ◽  
Jia Ling Chen ◽  
Ying Wei Luo
Keyword(s):  
Reaction Time ◽  
Sulfur Content ◽  
Atmospheric Pressure ◽  
Room Temperature ◽  
Oxidative Desulfurization ◽  
Sulfur Compounds ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Polymer Resin ◽  
Mild Conditions

Abstract. Investigation of polymer resin as catalyst in the oxidative desulfurization (ODS) process has revealed that the method can be applied to make a relative high removal of sulfur compounds. The reaction conditions, including temperature, amount of oxidant and reaction time were studied. The best result occurs under mild conditions with respect to room temperature and atmospheric pressure, to remove 75.54% of the totle sulfur content in the presence of H2O2 with an O/S molar ratio of 17. Possible mechanism is also disscussed.

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