Organotin carboxylate catalyst in urethane formation in a polar solvent: an experimental and computational study

RSC Advances ◽  
2015 ◽  
Vol 5 (60) ◽  
pp. 48935-48945 ◽  
Author(s):  
Ransi Devendra ◽  
Neil R. Edmonds ◽  
Tilo Söhnel
Keyword(s):  
Polar Solvent ◽  
Computational Study ◽  
Polar Solvents ◽  
Alkoxy Derivative ◽  
Urethane Formation

Organotin carboxylates catalyse aliphatic urethane reaction in polar solvents through an O-coordinated mechanism by forming an alkoxy derivative.

scholarly journals Recoverable Phospha-Michael Additions Catalyzed by a 4-N,N-Dimethylaminopyridinium Saccharinate Salt or a Fluorous Long-Chained Pyridine: Two Types of Reusable Base Catalysts

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1159
Author(s):  
Eskedar Tessema ◽  
Vijayanath Elakkat ◽  
Chiao-Fan Chiu ◽  
Jing-Hung Zheng ◽  
Ka Long Chan ◽  
...  
Keyword(s):  
Michael Addition ◽  
Polar Solvent ◽  
Addition Reaction ◽  
High Yield ◽  
Addition Reactions ◽  
Polar Solvents ◽  
Unsaturated Bond ◽  
Base Catalysts ◽  
Michael Additions

Phospha-Michael addition, which is the addition reaction of a phosphorus-based nucleophile to an acceptor-substituted unsaturated bond, certainly represents one of the most versatile and powerful tools for the formation of P-C bonds, since many different electrophiles and P nucleophiles can be combined with each other. This offers the possibility to access many diversely functionalized products. In this work, two kinds of basic pyridine-based organo-catalysts were used to efficiently catalyze phospha-Michael addition reactions, the 4-N,N-dimethylaminopyridinium saccharinate (DMAP·Hsac) salt and a fluorous long-chained pyridine (4-Rf-CH2OCH2-py, where Rf = C11F23). These catalysts have been synthesized and characterized by Lu’s group. The phospha-Michael addition of diisopropyl, dimethyl or triethyl phosphites to α, β-unsaturated malonates in the presence of those catalysts showed very good reactivity with high yield at 80–100 °C in 1–4.5 h with high catalytic recovery and reusability. With regard to significant catalytic recovery, sometimes more than eight cycles were observed for DMAP·Hsac adduct by using non-polar solvents (e.g., ether) to precipitate out the catalyst. In the case of the fluorous long-chained pyridine, the thermomorphic method was used to efficiently recover the catalyst for eight cycles in all the reactions. Thus, the easy separation of the catalysts from the products revealed the outstanding efficacy of our systems. To our knowledge, these are good examples of the application of recoverable organo-catalysts to the DMAP·Hsac adduct by using non-polar solvent and a fluorous long-chained pyridine under the thermomorphic mode in phospha-Michael addition reactions.

Evidences of Conformational Fluctuations of 2-methylaminofluorenone and 2-dimethylaminofluorenone in Polar Solvents

2004 ◽  
Vol 59 (3) ◽  
pp. 105-112 ◽  
Author(s):  
M. Józefowicza ◽  
J. R. Heldta ◽  
J. Heldta ◽  
J. Heldta
Keyword(s):  
Fluorescence Spectra ◽  
Polar Solvent ◽  
Reorganization Energy ◽  
Outer Sphere ◽  
Fluorescence Decay ◽  
Absorption And Fluorescence Spectra ◽  
Exponential Functions ◽  
Polar Solvents ◽  
Ground State Dipole Moment ◽  
Reorganization Energies

The absorption and fluorescence spectra of 2-methylaminofluorenone (2MAFl) and 2-dimethylaminofluorenone (2DMAFl) were determined at 293 K in a variety of solvents with different polarities. The spectral data were used, in combination with the 2MAFl and 2DMAFl ground state dipole moment (μg), to evaluate μe of the S1 state, to determine the outer-sphere solvent reorganization energy λouter, and the intramolecular reorganization energies: λ1 (associated with vibrations for which hv < kT) and λi(hv > kT). At 77 K the fluorescence spectra in a non-polar solvent are shifted to longer wavelengths. In polar solvents, for both molecules the behavior is opposite. The fluorescence decay data for 2MAFl and 2DMAFl in non-polar solvents are very well fitted by oneexponential functions, while in polar solvents by two-exponential functions. The spectroscopic data distinctly show that both studied molecules in polar solvents form an inhomogeneous emitting system.

Solvent structure. The use of internal pressure and cohesive energy density to examine contributions to solvent-solvent interactions

1975 ◽  
Vol 28 (8) ◽  
pp. 1643 ◽  
Author(s):  
MRJ Dack
Keyword(s):  
Energy Density ◽  
Internal Pressure ◽  
Cohesive Energy ◽  
Polar Solvent ◽  
Polar Solvents ◽  
Solvent Interactions ◽  
Cohesive Energy Density ◽  
Hexamethyl Phosphoramide ◽  
Internal Pressures ◽  
Solvent Solvent

Internal pressures, (∂U/∂V)T, have been obtained at 25� for the solvents dimethyl sulphoxide, propylene carbonate, formamide, dimethylformamide, acetonitrile, methanol and hexamethyl-phosphoramide by measurement of the thermal pressure coefficients. Data in the literature suggest that values of the internal pressure and the cohesive energy density, (ΔU/Vm), are similar for a non-polar solvent. The observed divergence of the two properties in the polar solvents under investigation is discussed in terms of the nature of the solvent-solvent interactions.

scholarly journals Synthesis, and studying effect of a solvent on the 1H-NMR chemical shifts of 4-Azido-N-(6-chloro-3-pyridazinyl)benzenesulfonamide

2021 ◽  
Vol 26 (3) ◽  
pp. 1-11
Author(s):  
Sadiq Hasan
Keyword(s):  
Chemical Shift ◽  
1H Nmr ◽  
Linear Correlation ◽  
Polar Solvent ◽  
Chemical Shifts ◽  
Marked Change ◽  
Dielectric Constants ◽  
Polar Solvents ◽  
Nmr Chemical Shifts ◽  
Small Chemical

  The compound 4-Azido-N-(6-chloro-3-pyridazinyl)benzenesulfonamide was synthesized and studied using FTIR, and 1H-NMR . The influence of a solvent on the experimental 1H-NMR chemical shifts of title compound is discussed. Small chemical shift Δδ < 0.1 ppm were observed when switching from DMSO-d6 to CD3OD. Record a marked change in chemical shifts valeues Δδ > 0.3 ppm when transform from high-polar solvents (DMSO-d6,and CD3OD)  to low-polar solvent (CDCl3). The 1H-NMR chemical shifts of C2-H and C6-H were shown to have excellent linear correlation with the dielectric constants of the solvents DMSO-d6, CD3OD,and CDCl3 (r = 0.995). The 1H-NMR chemical shifts of C18-H shows a perfect relationship with solvatochromic parameter β (r = 0.999).

scholarly journals The FA Polymerization Disruption by Protic Polar Solvent

2018 ◽  
Author(s):  
Guillaume Falco ◽  
Nathanael Guigo ◽  
Luc Vincent ◽  
Nicolas Sbirrazzuoli
Keyword(s):  
Activation Energy ◽  
Isopropyl Alcohol ◽  
Polar Solvent ◽  
Water System ◽  
Polar Solvents ◽  
Continuous Increase ◽  
Exponential Factor ◽  
Rubbery State ◽  
Higher Temperature ◽  
Lower Temperature

Furfuryl alcohol (FA) is a biobased monomer derived from lignocellulosic biomass. The present work describes its polymerization in presence of protic polar solvents, i.e. water or isopropyl alcohol (IPA), using maleic anhydride (MA) as acidic initiator. The polymerization was followed from the liquid to the rubbery state by combining DSC and DMA data. In the liquid state, IPA disrupts the expected reactions during all the FA polymerization due to a stabilization of the furfuryl carbenium center. This causes the initiation of the polymerization at higher temperature, which is also reflected by higher activation energy. In water system, the MA opening allows to start the reaction at lower temperature. A higher pre-exponential factor value is obtained in that case. The DMA study of final branching reaction occurring in the rubbery state has highlighted continuous increase of elastic modulus until 290 &deg;C. This increasing tendency of modulus was exploited to obtain activation energy dependences (E&alpha;) of FA polymerization in the rubbery state.

RESEARCH OF MICELLE FORMATION OF SOY LECITHINS PHOSPHOLIPIDS IN NON-POLAR SOLVENTS

2020 ◽  
Author(s):  
Е.П. Викторова ◽  
Е.В. Лисовая ◽  
М.Р. Жане ◽  
В.И. Мартовщук ◽  
Л.А. Марченко ◽  
...  
Keyword(s):  
Interfacial Tension ◽  
Polar Solvent ◽  
Critical Concentration ◽  
Micelle Formation ◽  
Quantitative Composition ◽  
Chemical Affinity ◽  
Soy Lecithin ◽  
Polar Solvents ◽  
The Difference ◽  
Model Oil

Исследован процесс мицеллообразования фосфолипидов соевых лецитинов в неполярных растворителях. Показано, что процесс мицеллообразования характеризуется двумя значениями критической концентрации мицеллообразования ККМ1 и ККМ2 для растворов фосфолипидов соевых лецитинов в модельном масле и CCl4. Отмечено, что межфазное натяжение растворов фосфолипидов в модельном масле при одной и той же концентрации и температуре ниже по сравнению с межфазным натяжением растворов фосфолипидов соевых лецитинов в CCl4, что объясняется большим химическим сродством молекул фосфолипидов и масла. Установлено в результате сравнения значений ККМ1 и ККМ2 фосфолипидов подсолнечных, рапсовых и соевых лецитинов в модельном масле и в CCl4, что способность к мицеллообразованию фосфолипидов соевых лецитинов в модельном масле и CCl4 ниже по сравнению с фосфолипидами подсолнечных и рапсовых лецитинов, что обусловлено различием в указанных лецитинах количественного состава отдельных групп фосфолипидов, в наибольшей степени способных к мицеллообразованию, а также большим содержанием в соевых лецитинах негидратируемых фосфолипидов, представленных комплексами с двух- и трехвалентными металлами. Отмечено, что проявление способности к мицеллообразованию фосфолипидами соевых лецитинов, как и фосфолипидами подсолнечных и рапсовых лецитинов, в CCl4 ниже, чем в модельном масле. Таким образом, подтверждена эффективность применения CCl4 в качестве неполярного растворителя, позволяющего снизить степень мицеллообразования фосфолипидов соевых лецитинов для разработки способа определения кислотного числа соевых лецитинов с применением импульсного метода ядерного магнитного резонанса. The process of micelle formation of soy lecithin phospholipids in non-polar solvents was studied. It is shown that the process of micelle formation is characterized by two values of the critical concentration of micelle formation KCM1 and KCM2 for solutions of soy lecithin phospholipids in model oil and CCl4. It is noted that the interfacial tension of phospholipid solutions in the model oil at the same concentration and temperature is lower compared to the interfacial tension of soy lecithin phospholipid solutions in CCl4, which is explained by the large chemical affinity of the phospholipids and oil molecules. As a result of comparing the KKM1 and KKM2 values of phospholipids of sunflower, rapeseed and soya lecithins in model oil and in CCl4, it was found that the ability to micelle formation of phospholipids of soya lecithins in both model oil and CCl4 is lower compared with sunflower and rape phospholipids, which the difference in the indicated lecithins in the quantitative composition of individual groups of phospholipids that are most capable of micelle formation, as well as the high content of non-hydratable phospholipids in soya lecithins, represented by complexes with bivalent and trivalent metals. It was noted that the manifestation of the ability to micelle formation by soy lecithin phospholipids, as well as sunflower and rapeseed lecithin phospholipids in CCl4 is lower than in model oil. Thus, the effectiveness of the use of CCl4 as a non-polar solvent has been confirmed, which allows to reduce the degree of micelle formation of soy lecithin phospholipids for the development of a method for determining the a

Ultraviolet Irradiation of Rubber

1940 ◽  
Vol 13 (3) ◽  
pp. 549-556 ◽  
Author(s):  
P. S. Srinivasan
Keyword(s):  
Ultraviolet Light ◽  
Ultraviolet Irradiation ◽  
Polar Solvent ◽  
Solvent Molecule ◽  
High State ◽  
Polar Solvents ◽  
Absorption Of Light ◽  
Before And After ◽  
Tentative Explanation ◽  
Absorption Phenomenon

Abstract The absorption of light by rubber when dissolved in polar and non-polar solvents was measured before and after exposing the solutions to ultraviolet light in the absence of air. It was found that irradiation with ultraviolet light makes rubber more transparent when in non-polar solvents and less transparent when in polar solvents. The state of rubber in solution is reviewed in the light of present-day knowledge, and a tentative explanation of the absorption phenomenon is suggested on the assumption that the rubber molecule in a polar solvent is depolymerized by the field of the solvent molecule and that ultraviolet light produces both polymerization and depolymerization of rubber, according as rubber initially is in a low or high state of polymerization. A probable support to this concept from measurements of viscosity is indicated.

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