Mobile Low-Field 1H NMR Spectroscopy Desktop Analysis of Biodiesel Production

2012 ◽  
Vol 44 (1-2) ◽  
pp. 41-53 ◽  
Author(s):  
Yamila Garro Linck ◽  
M. H. M. Killner ◽  
E. Danieli ◽  
B. Blümich
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Biodiesel Production ◽  
Low Field

Low-field 1H-NMR spectroscopy for compositional analysis of multicomponent polymer systems

The Analyst ◽  
2019 ◽  
Vol 144 (5) ◽  
pp. 1679-1686 ◽  
Author(s):  
Sneha B. Chakrapani ◽  
Michael J. Minkler ◽  
Bryan S. Beckingham
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Compositional Analysis ◽  
Polymer Systems ◽  
H Nmr ◽  
Low Field ◽  
Multicomponent Polymer

A low-field, 60 MHz, 1H NMR spectrometer yields quantitatively comparable results to 400 MHz spectrometers for the compositional analysis of multicomponent polymer systems.

Application of low-field and medium-resolution 1H NMR spectroscopy combined with chemometric methods for automotive gasoline quality control

Fuel ◽  
2020 ◽  
Vol 282 ◽  
pp. 118684
Author(s):  
Leticia Magalhães de Aguiar ◽  
Evandro Bona ◽  
Luiz Alberto Colnago ◽  
Jarbas J. Rodrigues Rohwedder ◽  
Mario Henrique M. Killner
Keyword(s):  
Quality Control ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Automotive Gasoline ◽  
Chemometric Methods ◽  
Low Field ◽  
Medium Resolution

scholarly journals Rapid Identification of Novel Psychoactive and Other Controlled Substances Using Low-Field 1H NMR Spectroscopy

ACS Omega ◽  
2019 ◽  
Vol 4 (4) ◽  
pp. 7103-7112 ◽  
Author(s):  
Lysbeth H. Antonides ◽  
Rachel M. Brignall ◽  
Andrew Costello ◽  
Jamie Ellison ◽  
Samuel E. Firth ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Rapid Identification ◽  
Controlled Substances ◽  
Low Field

scholarly journals Low-field 1H NMR spectroscopy for distinguishing between arabica and robusta ground roast coffees

2017 ◽  
Vol 216 ◽  
pp. 106-113 ◽  
Author(s):  
Marianne Defernez ◽  
Ella Wren ◽  
Andrew D. Watson ◽  
Yvonne Gunning ◽  
Ian J. Colquhoun ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Low Field

scholarly journals EVALUATION OF THE NA/NB2O5 SYSTEM IN THE TRANSESTERIFICATION OF SOYBEAN OIL FOR BIODIESEL PRODUCTION

2014 ◽  
Vol 39 (1) ◽  
pp. 35 ◽  
Author(s):  
Carlos Eduardo Garção de Carvalho ◽  
Nelson Consolin-Filho ◽  
Anelise Maria Regiani ◽  
Rogerio Antonio Sartori ◽  
Andréa Maria Duarte de Farias ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Soybean Oil ◽  
1H Nmr ◽  
Vegetable Oils ◽  
1H Nmr Spectroscopy ◽  
Heterogeneous Catalysts ◽  
Co2 Adsorption ◽  
Diesel Oil ◽  
Biodiesel Production ◽  
Structural Alterations

Biodiesel is considered an important substitute of diesel oil. Traditionally, it is obtained by the transesterification of vegetable oils with methanol or ethanol, catalyzed by NaOH or KOH. Heterogeneous catalysts have been studied with the aim at facilitating and diminishing costs with purification stages. In the present work, the Na/Nb2O5 system was evaluated on the reaction of soybean oil with ethanol. It was verified, by DRX and IR, that the niobia calcined at 500ºC and impregnated with sodium underwent greater structural alterations than that treated at 300°C. These modifications allowed the generation of basic properties on niobia surface (Hammett and CO2 adsorption /IR). This catalyst showed the highest conversion (30%) among the used materials. The method chosen for evaluating the catalysts yield was the 1H NMR spectroscopy.

Asymetrical Dimer - allyl-palladiu Complexes II. Data from Infrared Spectra and Chemical Behaviour

2008 ◽  
Vol 59 (7) ◽  
Author(s):  
Maria Maganu ◽  
Filip Chiraleu ◽  
Constantin Draghici ◽  
Gheorghe Mihai
Keyword(s):  
Carbon Monoxide ◽  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Infrared Spectra ◽  
Analytical Methods ◽  
1H Nmr Spectroscopy ◽  
Chemical Behaviour ◽  
The Asymmetry ◽  
Pd Complexes

The previous data obtained by 1H-NMR spectroscopy established the existence of an asymmetry of the bond between Pd and p-allylic groups, even in the p-allyl-Pd complexes dimers which are considered usually symmetric dimers. The asymmetry of the bond depends by the substitutes of the allylic group. Other analytical methods were investigated for additional proof of the obtained results. Thus, this paper discusses how this asymmetry would be reflected in the infrared spectra and in the reaction of the complexes with carbon monoxide.

Diastereoselective Reduction of Selected α-substituted β-keto Esters and the Assignment of the Relative Configuration by 1H-NMR Spectroscopy

2020 ◽  
Vol 07 ◽  
Author(s):  
Christian Trapp ◽  
Corinna Schuster ◽  
Chris Drewniok ◽  
Dieter Greif ◽  
Martin Hofrichter
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Selective Reduction ◽  
Reducing Agents ◽  
Relative Configuration ◽  
Curtius Rearrangement ◽  
Keto Esters ◽  
Hydroxy Esters ◽  
Diastereoselective Reduction

Background:: Chiral β-hydroxy esters and α-substituted β-hydroxy esters represent versatile building blocks for pheromones, β-lactam antibiotics and 1,2- or 1,3-aminoalcohols. Objective:: Synthesis of versatile α-substituted β-keto esters and their diastereoselective reduction to the corresponding syn- or anti-α-substituted β-hydroxy esters. Assignment of the relative configuration by NMR-spectroscopy after a CURTIUS rearrangement of α-substituted β-keto esters to 4-substituted 5-methyloxazolidin-2-ones. Method:: Diastereoselective reduction was achieved by using different LEWIS acids (zinc, titanium and cerium) in combination with complex borohydrides as reducing agents. Assignment of the relative configuration was verified by 1H-NMR spectroscopy after CURTIUS-rearrangement of α-substituted β-hydroxy esters to 4-substituted 5-methyloxazolidin-2-ones. Results:: For the syn-selective reduction, titanium tetrachloride (TiCl4) in combination with a pyridine-borane complex (py BH3) led to diastereoselectivities up to 99% dr. High anti-selective reduction was achieved by using cerium trichloride (CeCl3) and steric hindered reducing agents such as lithium triethylborohydride (LiEt3BH). After CURTIUS-rearrangement of each α-substituted β-hydroxy ester to the corresponding 4-substituted 5-methyloxazolidin-2-one, the relative configuration was confirmed by 1H NMR-spectroscopy. Conclusion:: We have expanded the procedure of LEWIS acid-mediated diastereoselective reduction to bulky α-substituents such as the isopropyl group and the electron withdrawing phenyl ring.

Sign in / Sign up

Export Citation Format

Share Document