scholarly journals Nanofiber-Membrane-Supported TiO2as a Catalyst for Oxidation of Benzene to Phenol

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chanbasha Basheer
Keyword(s):  
Low Cost ◽  
Laboratory Scale ◽  
Gas Chromatography Mass Spectrometry ◽  
Nanofiber Membrane ◽  
Ambient Conditions ◽  
Glass Capillary ◽  
Reaction Conditions ◽  
Capillary Microreactor ◽  
Oxidation Of Benzene

We applied a simple, low-cost design of glass capillary microreactor for the catalytic oxidation of benzene to phenol at ambient conditions. Polyvinylchloride-nanofiber-membrane-supported titania nanoparticle (TiO2-PVC) as catalyst and in situ production of hydroxyl radicals as oxidant. The reaction was monitored by gas chromatography-mass spectrometry (GC-MS). The reaction conditions were optimized and the performance of the microreactor was then compared with the conventional laboratory scale reaction which used hydrogen peroxide as oxidant. The microreactor gave a better yield of 14% for phenol compared to 0.14% in the conventional laboratory scale reaction. Reaction conditions such as reaction time, reaction pH, and applied potential were optimized. With optimized reaction conditions selectivity of >37% and >88% conversion of benzene were obtained.

OXIDATION OF CYCLOHEXENE IN A SIMPLE CAPILLARY-MICROREACTOR

2005 ◽  
Vol 04 (04) ◽  
pp. 599-606 ◽  
Author(s):  
CHANBASHA BASHEER ◽  
MUTHALAGU VETRICHELVAN ◽  
AGAMPODI PROMODA P. PERERA ◽  
SURESH VALIYAVEETTIL ◽  
HIAN KEE LEE
Keyword(s):  
Gas Chromatography Mass Spectrometry ◽  
Reaction Yield ◽  
Oxidation Reactions ◽  
Reaction Products ◽  
Glass Capillary ◽  
Reaction Conditions ◽  
Catalyst Screening ◽  
Capillary Microreactor ◽  
Reduced Schiff Base ◽  
Reaction Performance

A simple glass capillary-microreactor for studying the epoxidation of cyclohexene is described in this paper. Reaction conditions were optimized to achieve high reaction yield. The microreactor is easy to fabricate, fast and easy way for reliable catalyst screening in studying homogeneous oxidation reactions. Four different catalysts (i.e. manganese(II) and copper(II) metal complexes of Schiff and reduced Schiff base ligands) were synthesized and used. The reaction products were monitored by gas chromatography/mass spectrometry. The reaction performance was compared with conventional (batch scale) reaction. In both cases, catalytic activities and the product yields were found to be relatively higher for the copper(II) complexes when compared with the conventional route.

Coagulation pretreatment of highly concentrated acrylonitrile wastewater from petrochemical plants

2014 ◽  
Vol 70 (2) ◽  
pp. 345-351 ◽  
Author(s):  
Dongju Zheng ◽  
Lin Qin ◽  
Tao Wang ◽  
Xiaojing Ren ◽  
Zhongguo Zhang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Energy Saving ◽  
Industrial Application ◽  
Low Cost ◽  
Laboratory Scale ◽  
Operational Cost ◽  
Reaction Conditions ◽  
Chemical Methods ◽  
Pretreatment Method

Acrylonitrile (AN) wastewater is a heavily polluted and a likely hazardous liquid that is generated during the production of AN. Several chemical methods for the pretreatment of AN wastewater are available in laboratory scale. However, the harsh reaction conditions and high operational cost make these methods undesirable. Until now, four-effect evaporation is the only pretreatment method used for AN wastewater in industry despite its huge energy consumption and high cost. It is difficult to find an energy-saving pretreatment technique from the perspective of industrial application. In this study, a safe and low-cost coagulation technique was developed for the pretreatment of AN wastewater. Three types of inorganic coagulant and three types of polymer coagulant were investigated for the coagulation treatment of highly concentrated AN wastewater from petrochemical plants. The effects of coagulant type, dosage, and coagulation conditions on the pretreatment efficiency of AN wastewater were investigated. The results show that a combination of inorganic and polymer coagulants is effective for the pretreatment of AN wastewater.

scholarly journals Portable, handheld, and affordable blood perfusion imager for screening of subsurface cancer in resource-limited settings

2022 ◽  
Vol 119 (2) ◽  
pp. e2026201119
Author(s):  
Arka Bhowmik ◽  
Biswajoy Ghosh ◽  
Mousumi Pal ◽  
Ranjan Rashmi Paul ◽  
Jyotirmoy Chatterjee ◽  
...  
Keyword(s):  
Low Cost ◽  
Medical Image Analysis ◽  
Blood Perfusion ◽  
Ambient Conditions ◽  
Noninvasive Diagnostics ◽  
Resource Limited ◽  
Double Blinded ◽  
User Friendly ◽  
Contact Free

Precise information on localized variations in blood circulation holds the key for noninvasive diagnostics and therapeutic assessment of various forms of cancer. While thermal imaging by itself may provide significant insights on the combined implications of the relevant physiological parameters, viz. local blood perfusion and metabolic balance due to active tumors as well as the ambient conditions, knowledge of the tissue surface temperature alone may be somewhat inadequate in distinguishing between some ambiguous manifestations of precancer and cancerous lesions, resulting in compromise of the selectivity in detection. This, along with the lack of availability of a user-friendly and inexpensive portable device for thermal-image acquisition, blood perfusion mapping, and data integration acts as a deterrent against the emergence of an inexpensive, contact-free, and accurate in situ screening and diagnostic approach for cancer detection and management. Circumventing these constraints, here we report a portable noninvasive blood perfusion imager augmented with machine learning–based quantitative analytics for screening precancerous and cancerous traits in oral lesions, by probing the localized alterations in microcirculation. With a proven overall sensitivity >96.66% and specificity of 100% as compared to gold-standard biopsy-based tests, the method successfully classified oral cancer and precancer in a resource-limited clinical setting in a double-blinded patient trial and exhibited favorable predictive capabilities considering other complementary modes of medical image analysis as well. The method holds further potential to achieve contrast-free, accurate, and low-cost diagnosis of abnormal microvascular physiology and other clinically vulnerable conditions, when interpreted along with complementary clinically evidenced decision-making perspectives.

scholarly journals Optimisation and Scale-up of the Synthesis of Gold Nanoparticle-Wool Fibre Composites

2021 ◽  
Author(s):  
◽  
Thomas Wade Nilsson
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Laboratory Scale ◽  
Metal Nanoparticle ◽  
Ex Situ ◽  
Wool Fibre ◽  
Reaction Conditions ◽  
Gold Colloids ◽  
Fibre Composites

<p>Gold nanoparticles are known for their remarkable optical properties; they exhibit localised surface plasmon resonance bands in the visible region of the electromagnetic spectrum. This has led to their use as luxury dyes for the colouring of wool fibres. Gold is associated with wealth and desire, and as such, gold nanoparticle-wool fibre composites may be fabricated into high-quality garments, apparel, textiles and carpets for international markets.  Novel proprietary approaches for the laboratory-scale synthesis of gold nanoparticle-wool fibre composites have previously been developed by Professor James Johnston and Dr Kerstin Lucas. The innovative nanotechnology utilises the affinity of gold for sulfur-containing cystine residues in wool fibres, to attract and bind the gold nanoparticles. One approach involves the absorption of gold ions by wool fibres and the nucleation of gold nanoparticles in-situ. In an alternative method, gold nanoparticle colloids are synthesised ex-situ, and are then used to colour wool fibres.  The reaction conditions of the in-situ and ex-situ approaches were optimised with respect to cost-effectiveness and scalability. The gold content of the in-situ composites was minimised, and the range of possible colours widened, via the use of heat and external reducing agents. In the ex-situ process, the formation and stability of the gold nanoparticle colloids was studied, and the reaction conditions of the synthesis were optimised. The rate of uptake of gold nanoparticles to wool was controlled by manipulating the pH, concentration, volume, and wool to liquor ratio of the gold colloids, and by introducing auxiliary agents into the dyeing reactions. A range of chemical treatments and alternative stabilising agents were investigated to improve the washfastness properties of ex-situ gold nanoparticle-wool fibre composites.  There are numerous size-controllable syntheses of gold nanoparticle colloids at the laboratory-scale. However, when the process is scaled-up, gold nanoparticle synthesis is no longer trivial. A barrel reactor with a high velocity mixer was utilised to achieve uniform mixing and heating in the synthesis of gold nanoparticle colloids of up to 90 L in volume. The ratios of gold to stabilising agents in the colloidal gold syntheses were optimised to result in more stable and reproducible gold colloids for subsequent dyeing reactions.  The uniform colouring of small quantities of wool is easily achieved in the laboratory, but preventing colour variation across a kilogram of wool is a significant challenge. Initial kilogram-scale dyeing reactions in static tank reactors resulted in unevenly coloured gold nanoparticle-wool fibre composites. To overcome this, conventional hank dyeing equipment was used to colour felted merino yarn, in collaboration with the wool dyeing industry. Modified hank dyeing procedures were recreated in the laboratory, and composites with remarkable colour uniformity were produced. Industrial package dyeing reactors were then used to colour fine merino yarn with gold nanoparticle colloids. The uptake of gold nanoparticles was controlled by manipulating the owrates, ow direction and amounts of auxiliary agents that were employed in the dyeing reactions.  Based upon the success of the industrial dyeing reactions, novel dyeing reactors were developed for the colouring of hanks of wool fibres and yarns in the laboratory. These reactors utilised rapid dye circulation and pressure to produce gold nanoparticle-wool fibre composites with remarkable colour uniformity. The composites were used to fabricate luxury apparel and carpets for international trade expositions.  The pathway from synthesis in the laboratory to pilot-scale production of gold nanoparticle-wool fibre composites is presented. The PhD research was an integral step in the successful commercialisation of this innovative nanotechnology, and will assist in scaling-up the synthesis of metal nanoparticle colloids and nanocomposites in the future.</p>

One-Pot Catalytic Epoxidation Reaction of Perfluoro-2-methyl-2-pentene with Tri-n-butylamine N-Oxide or N, N-Dimethylcyclohexylamine N-Oxide

2013 ◽  
Vol 685 ◽  
pp. 357-361 ◽  
Author(s):  
Min Sha ◽  
Ren Ming Pan ◽  
Biao Jiang
Keyword(s):  
Organic Chemistry ◽  
Hydrogen Peroxide ◽  
Low Cost ◽  
Reaction Conditions ◽  
One Pot ◽  
Catalytic Epoxidation ◽  
Epoxidation Reaction ◽  
Work Up ◽  
Better Than

Perfluoro epoxy compounds are important intermediates in organic chemistry, however, the methods for preparing them are scanty. We found that in situ generated tri-n-butylamine N-oxide and N,N-Dimethylcyclohexylamine N-oxide were found to be good reagents for the epoxidation of tri-substituted Perfluoro-2-methyl-2-pentene in good to excellent yields. Catalytic epoxidation methods were developed by coupling this reaction with the N-oxidation of tertiary amine by hydrogen peroxide or MCPBA. The advantages of these methods are easy work-up, mild reaction conditions, environmentally friendly and low cost. The reaction using MCPBA as a oxidant is better than hydrogen peroxide for it is fast and high yielding.

scholarly journals In Situ X-Ray Photoelectron Spectroscopy Studies of Gas-Solid Interfaces at Near-Ambient Conditions

MRS Bulletin ◽  
2007 ◽  
Vol 32 (12) ◽  
pp. 1022-1030 ◽  
Author(s):  
Hendrik Bluhm ◽  
Michael Hävecker ◽  
Axel Knop-Gericke ◽  
Maya Kiskinova ◽  
Robert Schlögl ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Lens System ◽  
Ambient Conditions ◽  
Reaction Conditions ◽  
X Ray ◽  
Heterogeneous Catalytic ◽  
Probing Depth ◽  
Gas Molecules ◽  
Spectroscopy Studies

AbstractX-ray photoelectron spectroscopy (XPS) is a quantitative, chemically specific technique with a probing depth of a few angstroms to a few nanometers. It is therefore ideally suited to investigate the chemical nature of the surfaces of catalysts. Because of the scattering of electrons by gas molecules, XPS is generally performed under vacuum conditions. However, for thermodynamic and/or kinetic reasons, the catalyst's chemical state observed under vacuum reaction conditions is not necessarily the same as that of a catalyst under realistic operating pressures. Therefore, investigations of catalysts should ideally be performed under reaction conditions, that is, in the presence of a gas or gas mixtures. Using differentially pumped chambers separated by small apertures, XPS can operate at pressures of up to 1 Torr, and with a recently developed differentially pumped lens system, the pressure limit has been raised to about 10 Torr. Here, we describe the technical aspects of high-pressure XPS and discuss recent applications of this technique to oxidation and heterogeneous catalytic reactions on metal surfaces.

scholarly journals Optimisation and Scale-up of the Synthesis of Gold Nanoparticle-Wool Fibre Composites

2021 ◽  
Author(s):  
◽  
Thomas Wade Nilsson
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Laboratory Scale ◽  
Metal Nanoparticle ◽  
Ex Situ ◽  
Wool Fibre ◽  
Reaction Conditions ◽  
Gold Colloids ◽  
Fibre Composites

<p>Gold nanoparticles are known for their remarkable optical properties; they exhibit localised surface plasmon resonance bands in the visible region of the electromagnetic spectrum. This has led to their use as luxury dyes for the colouring of wool fibres. Gold is associated with wealth and desire, and as such, gold nanoparticle-wool fibre composites may be fabricated into high-quality garments, apparel, textiles and carpets for international markets.  Novel proprietary approaches for the laboratory-scale synthesis of gold nanoparticle-wool fibre composites have previously been developed by Professor James Johnston and Dr Kerstin Lucas. The innovative nanotechnology utilises the affinity of gold for sulfur-containing cystine residues in wool fibres, to attract and bind the gold nanoparticles. One approach involves the absorption of gold ions by wool fibres and the nucleation of gold nanoparticles in-situ. In an alternative method, gold nanoparticle colloids are synthesised ex-situ, and are then used to colour wool fibres.  The reaction conditions of the in-situ and ex-situ approaches were optimised with respect to cost-effectiveness and scalability. The gold content of the in-situ composites was minimised, and the range of possible colours widened, via the use of heat and external reducing agents. In the ex-situ process, the formation and stability of the gold nanoparticle colloids was studied, and the reaction conditions of the synthesis were optimised. The rate of uptake of gold nanoparticles to wool was controlled by manipulating the pH, concentration, volume, and wool to liquor ratio of the gold colloids, and by introducing auxiliary agents into the dyeing reactions. A range of chemical treatments and alternative stabilising agents were investigated to improve the washfastness properties of ex-situ gold nanoparticle-wool fibre composites.  There are numerous size-controllable syntheses of gold nanoparticle colloids at the laboratory-scale. However, when the process is scaled-up, gold nanoparticle synthesis is no longer trivial. A barrel reactor with a high velocity mixer was utilised to achieve uniform mixing and heating in the synthesis of gold nanoparticle colloids of up to 90 L in volume. The ratios of gold to stabilising agents in the colloidal gold syntheses were optimised to result in more stable and reproducible gold colloids for subsequent dyeing reactions.  The uniform colouring of small quantities of wool is easily achieved in the laboratory, but preventing colour variation across a kilogram of wool is a significant challenge. Initial kilogram-scale dyeing reactions in static tank reactors resulted in unevenly coloured gold nanoparticle-wool fibre composites. To overcome this, conventional hank dyeing equipment was used to colour felted merino yarn, in collaboration with the wool dyeing industry. Modified hank dyeing procedures were recreated in the laboratory, and composites with remarkable colour uniformity were produced. Industrial package dyeing reactors were then used to colour fine merino yarn with gold nanoparticle colloids. The uptake of gold nanoparticles was controlled by manipulating the owrates, ow direction and amounts of auxiliary agents that were employed in the dyeing reactions.  Based upon the success of the industrial dyeing reactions, novel dyeing reactors were developed for the colouring of hanks of wool fibres and yarns in the laboratory. These reactors utilised rapid dye circulation and pressure to produce gold nanoparticle-wool fibre composites with remarkable colour uniformity. The composites were used to fabricate luxury apparel and carpets for international trade expositions.  The pathway from synthesis in the laboratory to pilot-scale production of gold nanoparticle-wool fibre composites is presented. The PhD research was an integral step in the successful commercialisation of this innovative nanotechnology, and will assist in scaling-up the synthesis of metal nanoparticle colloids and nanocomposites in the future.</p>

scholarly journals Absolute Configuration of In Situ Crystallized (+)-γ-Decalactone

Chemistry ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 578-584
Author(s):  
Michael Patzer ◽  
Nils Nöthling ◽  
Richard Goddard ◽  
Christian W. Lehmann
Keyword(s):  
Asymmetric Catalysis ◽  
Absolute Configuration ◽  
Pharmaceutical Research ◽  
Optical Rotatory Dispersion ◽  
Pure Liquid ◽  
Ambient Conditions ◽  
Glass Capillary ◽  
The Absolute

Knowledge about the absolute configuration of small bioactive organic molecules is essential in pharmaceutical research because enantiomers can exhibit considerably different effects on living organisms. X-ray crystallography enables chemists to determine the absolute configuration of an enantiopure compound due to anomalous dispersion. Here, we present the determination of the absolute configuration of the flavoring agent (+)-γ-decalactone, which is liquid under ambient conditions. Single crystals were grown from the liquid in a glass capillary by in situ cryo-crystallization. Diffraction data collection was performed using Cu-Kα radiation. The absolute configuration was confirmed. The molecule consists of a linear aliphatic non-polar backbone and a polar lactone head. In the solid state, layers of polar and non-polar sections of the molecule alternating along the c-axis of the unit cell are observed. In favorable cases, this method of absolute configuration determination of pure liquid (bioactive) agents or liquid products from asymmetric catalysis is a convenient alternative to conventional methods of absolute structure determination, such as optical rotatory dispersion, vibrational circular dichroism, ultraviolet-visible spectroscopy, use of chiral shift reagents in proton NMR and Coulomb explosion imaging.

Synthesis of Al2O3–SiC from kyanite precursor

2001 ◽  
Vol 16 (6) ◽  
pp. 1609-1613 ◽  
Author(s):  
A. Amroune ◽  
G. Fantozzi
Keyword(s):  
Low Cost ◽  
Molar Ratio ◽  
High Alumina ◽  
Main Reaction ◽  
Reaction Sequence ◽  
Reaction Conditions ◽  
High Alumina Content ◽  
Natural Aluminosilicate ◽  
Sic Whiskers

Carbothermal reduction of kyanite, a natural aluminosilicate with high alumina content (Al2O3 · SiO2), was used as a way to synthesize SiC–Al2O3 powder. Carbon black was mixed with the mineral precursor in a molar ratio of (C/SiO2) = 5.5. The Carbothermal reaction sequence was studied in the temperature range 1260–1550 °C. Completion of the reaction at 1550 °C gave β–SiC-whiskers and α–Al2O3 particles as final products. From observations, the impurities contained in the mineral precursor behave as catalysts for the vapor–liquid–solid whisker growth mechanism. When the specific surface area of the starting carbon was increased from 330 to 996 m2/g, the carbothermal reaction rate increased but the morphology of the SiC-whiskers became very irregular. This study aimed to identify the main reaction conditions for obtaining a favorable morphology of the synthesized powder for elaborating Al2O3–SiC-whisker composite materials by using low cost starting materials and a relatively simple in situ synthesis route in comparison to the conventional way of separately preparing the phases SiC (whiskers) and Al2O3 before elaborating composites.

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