Comparison of in-line NIR, Raman and UV-visible spectrometries, and at-line NMR spectrometry for the monitoring of an esterification reaction

The Analyst ◽  
2002 ◽  
Vol 127 (2) ◽  
pp. 287-292 ◽  
Author(s):  
Colin A. McGill ◽  
Alison Nordon ◽  
David Littlejohn
Keyword(s):  
Esterification Reaction ◽  
Nmr Spectrometry ◽  
Uv Visible

scholarly journals Group 13 Lewis Acid Catalyzed Synthesis of Cu2O Nanocrystals via Hydroxide Transmetallation

2021 ◽  
Author(s):  
Noah Gibson ◽  
Alexandria R. C. Bredar ◽  
Byron Farnum
Keyword(s):  
Oleyl Alcohol ◽  
Copper Ions ◽  
Colloidal Synthesis ◽  
Esterification Reaction ◽  
Group 13 ◽  
Oleyl Oleate ◽  
Acid Catalyzed ◽  
Uv Visible ◽  
Continuous Injection ◽  
Injection Procedure

The colloidal synthesis of metal oxide nanocrystals (NCs) in oleyl alcohol requires the metal to catalyze an esterification reaction with oleic acid to produce oleyl oleate ester and M-OH monomers, which then condense to form MxOy solids. Here we show that the synthesis of Cu2O NCs by this method is limited by the catalytic ability of copper to drive esterification and thus produce Cu+ -OH monomers. However, inclusion of 1-15 mol% of a group 13 cation (Al3+, Ga3+ , or In3+) results in increased yields for the consumption of copper ions toward Cu2O formation and exhibits size/morphology control based on the nature of M3+ . Using a continuous-injection procedure where the copper precursor (Cu2+ -oleate) and catalyst (M3+ -oleate) are injected into oleyl alcohol at a controlled rate, we are able to monitor the reactivity of the precursor and M3+ catalyst using UV-visible and FTIR absorbance spectroscopies. These time-dependent measurements clearly show that M3+ catalysts drive esterification to produce M3+ -OH species, which then undergo transmetallation of hydroxide ligands to generate Cu+ -OH monomers required for Cu2O condensation. Ga3+ is found to be the “goldilocks” catalyst, producing NCs with the smallest size and a distinct cubic morphology not observed for any other group 13 metal. This is believed to be due to rapid transmetallation kinetics between Ga3+ -OH and Cu + -oleate. These studies introduce a new mechanism for the synthesis of metal oxides where inherent catalysis by the parent metal (i.e. copper) can be circumvented with the use of a secondary catalyst to generate -OH ligands.

scholarly journals Group 13 Lewis Acid Catalyzed Synthesis of Cu2O Nanocrystals via Hydroxide Transmetallation

2021 ◽  
Author(s):  
Noah Gibson ◽  
Alexandria R. C. Bredar ◽  
Byron Farnum
Keyword(s):  
Oleyl Alcohol ◽  
Copper Ions ◽  
Colloidal Synthesis ◽  
Esterification Reaction ◽  
Group 13 ◽  
Oleyl Oleate ◽  
Acid Catalyzed ◽  
Uv Visible ◽  
Continuous Injection ◽  
Injection Procedure

The colloidal synthesis of metal oxide nanocrystals (NCs) in oleyl alcohol requires the metal to catalyze an esterification reaction with oleic acid to produce oleyl oleate ester and M-OH monomers, which then condense to form MxOy solids. Here we show that the synthesis of Cu2O NCs by this method is limited by the catalytic ability of copper to drive esterification and thus produce Cu+ -OH monomers. However, inclusion of 1-15 mol% of a group 13 cation (Al3+, Ga3+ , or In3+) results in increased yields for the consumption of copper ions toward Cu2O formation and exhibits size/morphology control based on the nature of M3+ . Using a continuous-injection procedure where the copper precursor (Cu2+ -oleate) and catalyst (M3+ -oleate) are injected into oleyl alcohol at a controlled rate, we are able to monitor the reactivity of the precursor and M3+ catalyst using UV-visible and FTIR absorbance spectroscopies. These time-dependent measurements clearly show that M3+ catalysts drive esterification to produce M3+ -OH species, which then undergo transmetallation of hydroxide ligands to generate Cu+ -OH monomers required for Cu2O condensation. Ga3+ is found to be the “goldilocks” catalyst, producing NCs with the smallest size and a distinct cubic morphology not observed for any other group 13 metal. This is believed to be due to rapid transmetallation kinetics between Ga3+ -OH and Cu + -oleate. These studies introduce a new mechanism for the synthesis of metal oxides where inherent catalysis by the parent metal (i.e. copper) can be circumvented with the use of a secondary catalyst to generate -OH ligands.

Chimie des pigments anthocyaniques. 4. Spectre d’absorption UV-visible de la forme chalcone de la glucoside-3 malvidine

1979 ◽  
Vol 76 ◽  
pp. 273-276 ◽  
Author(s):  
R. Brouillard ◽  
B. Delaporte ◽  
J. M. EL Hage Chahine ◽  
J. E. Dubois
Keyword(s):  
Uv Visible

Infrared and UV-visible spectra of layer semiconductors Gas, GaSe and GaTe

1977 ◽  
Vol 38 (10) ◽  
pp. 1293-1299 ◽  
Author(s):  
U. Giorgianni ◽  
G. Mondio ◽  
P. Perillo ◽  
G. Saitta ◽  
G. Vermiglio
Keyword(s):  
Visible Spectra ◽  
Uv Visible

Investigation of Some Characterizations of Black TiO\(_2\) Nanotubes Via Spectroscopic Methods

2019 ◽  
Vol 29 (2) ◽  
pp. 189 ◽  
Author(s):  
Tho Truong Nguyen ◽  
Thi Minh Cao ◽  
Hieu Van Le ◽  
Viet Van Pham
Keyword(s):  
Water Splitting ◽  
Oxygen Vacancies ◽  
Light Response ◽  
Nanotube Arrays ◽  
Spectroscopic Methods ◽  
Visible Light Response ◽  
Uv Visible ◽  
Visible Reflectance ◽  
Splitting Effect ◽  
Anodization Method

The black TiO\(_2\) with substantial Ti\(^3+\) and oxygen vacancies exhibit an excellent photoelectrochemical water-splitting performance due to the improved charge transport the extended visible light response. In this study, black TiO\(_2\) nanotube arrays synthesized by the anodization method, and then, they have been investigated some characterizations by spectroscopic methods such as UV-visible reflectance (UV-vis DRS), Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, and photoluminescence spectrum. The results showed that some highlighted properties of the black TiO2 nanotube arrays and they could apply for water-splitting effect.

PEMBUATAN SURFAKTAN DARI ASAM OLEAT

2019 ◽  
Vol 1 (3) ◽  
pp. 68
Author(s):  
Puguh Setyopratomo ◽  
Edy Purwanto ◽  
H. Yefrico ◽  
H. Yefrico
Keyword(s):  
Oleic Acid ◽  
Optimum Condition ◽  
Reaction Temperature ◽  
Catalyst Concentration ◽  
Acid Number ◽  
Esterification Reaction ◽  
Number Density ◽  
Sample Analysis ◽  
Reaction Conversion ◽  
Glycerol Mono

The synthesis of glycerol mono oleic from oleic acid and glycerol is classified as an esterification reaction. This research is aimed to study the influent of reaction temperature and catalyst concentration on reaction conversion. During the experiment the temperature of reaction mixture was varied as 110 oC, 130 oC, and 150 oC, while the catalyst concentration of 1%, 3 %, and 5% was used. The batch experiment was conducted in a glass reactor equipped with termometer, agitator, and reflux condensor. The oleic acid – glycerol mol ratio of 1 : 2 was used as a mixture feed. To maintain the reaction temperature at certain level, the oil bath was used. After the temperature of reaction mixture was reached the expected value, then H2SO4 catalyst was added to the reactor.  To measure the extent of the reaction, every 30 minutes the sample was drawn out from the reactor vessel. The sample analysis include acid number, density, and viscosity measurement. From this research the optimum condition which is the temperature of reaction of 150 oC and 1% catalyst concentration was obtained. At this optimum condition the convertion reach 86% and the analysis of other physical properties of the product show the acid number of 24.12, the density of 0.922 g/cc, and the viscosity of 118.4 cp.

Biocompatibility of Silver Nano Bio-conjugates from Vitis vinifera Seeds and its Major Component Resveratrol

2016 ◽  
Vol 6 (3) ◽  
Author(s):  
R. Preethi ◽  
P. Padma
Keyword(s):  
Zeta Potential ◽  
Vitis Vinifera ◽  
Silver Ions ◽  
Seed Extract ◽  
Polydispersity Index ◽  
Potential Range ◽  
Visible Spectroscopy ◽  
Grape Seeds ◽  
X Ray ◽  
Uv Visible

The study focused on the green synthesis of silver nanobioconjugates (AgNPs) from phenolic-rich fruit source, Vitis vinifera seed extract and its major component phenolic, resveratrol respectively. Sunlight exposure for 20 minutes was the method of choice for the synthesis of AgNPs of the extract as well as the phenolic, resveratrol. The synthesized nanobioconjugates were characterized using UV-Visible spectroscopy, Transmission electron microscopy (TEM), Energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), Polydispersity index, Zeta potential and Fourier transform infrared spectroscopy (FTIR). The reduction of silver ions was confirmed by UV-visible spectroscopy with peaks at 440nm for both nanobioconjugates synthesized from seed extract and compound. The nanobioconjugates showed the spherical in shape with 14-35nm in size and crystalline in nature. The conjugates are well dispersed with 0.301 and 0.287 polydispersity index and the zeta potential range at -13.6 and -14.3mV for stability. The FTRI data proved that the components in grape seeds act as good reductants and stabilizers for the silver nanobioconjugate synthesis. All the synthesized nanobioconjugates exhibited steady and sustained release of the medicinal components conjugated, proving their druggability, and were biocompatible with human cells, demonstrating their safety. The findings of the study validate the anticancer properties of silver nanobioconjugates of Vitis vinifera and its active component resveratrol.

Liquid-liquid extraction of succinate using a dicopper cryptate

2020 ◽  
Author(s):  
Riccardo Mobili ◽  
Sonia La Cognata ◽  
Francesca Merlo ◽  
Andrea Speltini ◽  
Massimo Boiocchi ◽  
...  
Keyword(s):  
Aqueous Phase ◽  
Visible Spectrum ◽  
Tca Cycle ◽  
Residual Concentration ◽  
Waste Products ◽  
Liquid Liquid Extraction ◽  
The Tca Cycle ◽  
Quantitative Extraction ◽  
Uv Visible

<div> <p>The extraction of the succinate dianion from a neutral aqueous solution into dichloromethane is obtained using a lipophilic cage-like dicopper(II) complex as the extractant. The quantitative extraction exploits the high affinity of the succinate anion for the cavity of the azacryptate. The anion is effectively transferred from the aqueous phase, buffered at pH 7 with HEPES, into dichloromethane. A 1:1 extractant:anion adduct is obtained. Extraction can be easily monitored by following changes in the UV-visible spectrum of the dicopper complex in dichloromethane, and by measuring the residual concentration of succinate in the aqueous phase by HPLC−UV. Considering i) the relevance of polycarboxylates in biochemistry, as e.g. normal intermediates of the TCA cycle, ii) the relevance of dicarboxylates in the environmental field, as e.g. waste products of industrial processes, and iii) the recently discovered role of succinate and other dicarboxylates in pathophysiological processes including cancer, our results open new perspectives for research in all contexts where selective recognition, trapping and extraction of polycarboxylates is required. </p> </div>

Engine Performance with Diesel-Biodiesel Blends Fuel and Emission Characteristics

2020 ◽  
Vol 38 (5A) ◽  
pp. 779-788
Author(s):  
Marwa N. Kareem ◽  
Adel M. Salih
Keyword(s):  
Sulfur Content ◽  
Diesel Fuel ◽  
Engine Performance ◽  
Esterification Reaction ◽  
Biodiesel Fuel ◽  
Exhaust Gas ◽  
Gas Temperature ◽  
Biodiesel Blends ◽  
Fuel Blends ◽  
Hc Emissions

In this study, the sunflowers oil was utilized as for producing biodiesel via a chemical operation, which is called trans-esterification reaction. Iraqi diesel fuel suffers from high sulfur content, which makes it one of the worst fuels in the world. This study is an attempt to improve the fuel specifications by reducing the sulfur content of the addition of biodiesel fuel to diesel where this fuel is free of sulfur and has a thermal energy that approaches to diesel.20%, 30% and 50% of Biodiesel fuel were added to the conventional diesel. Performance tests and pollutants of a four-stroke single-cylinder diesel engine were performed. The results indicated that the brake thermal efficiency a decreased by (4%, 16%, and 22%) for the B20, B30 and B50, respectively. The increase in specific fuel consumption was (60%, 33%, and 11%) for the B50, B30, and B20 fuels, respectively for the used fuel blends compared to neat diesel fuel. The engine exhaust gas emissions measures manifested a decreased of CO and HC were CO decreased by (13%), (39%) and (52%), and the HC emissions were lower by (6.3%), (32%), and (46%) for B20, B30 and B50 respectively, compared to diesel fuel. The reduction of exhaust gas temperature was (7%), (14%), and (32%) for B20, B30 and B50 respectively. The NOx emission increased with the increase in biodiesel blends ratio. For B50, the raise was (29.5%) in comparison with diesel fuel while for B30 and B20, the raise in the emissions of NOx was (18%) and...

Sign in / Sign up

Export Citation Format

Share Document