7 research outputs found
Green Synthesis of Novel Polyesterurethane Materials from Epoxides and Carbon Dioxide by New Set of One-Dimensional Coordination Polymer Catalyst
Two
novel polyesterurethane materials, PEU1 and PEU2, were synthesized via nontoxic and isocyanate-free route
by simple conversion of two epoxides 1,2-epoxy-3-phenoxy propane (2) and styrene epoxide (3) utilizing CO2. Epoxides 2 and 3 were converted to the
respective cyclic carbonates 4 and 5 by
a new set of cobalt-based catalyst 1a in the presence
of 10 bar of CO2 and 80 °C temperature without using
cocatalyst tetrabutylammonium bromide (TBAB). The mechanistic pathway
of the catalysis reaction for the cycloaddition of epoxides with CO2 to generate the cyclic carbonates was investigated by several
spectroscopic techniques and utilizing analogous zinc-based 1D coordination
polymer 1b, which does not act as an efficient catalyst
in the absence of TBAB. Cyclic carbonates 4 and 5 were converted to the respective polyesterurethanes PEU1 and PEU2 sequentially by first synthesizing
the ring-opened diols 6 and 7 reacting with
ethylenediamine and subsequently annealing the respective diols 6 and 7 at 120 °C in the presence of terepthalyl
chloride and triethylamine. The polyesterurethanes PEU1 and PEU2 were characterized by multinuclear NMR and
FTIR. PEU1 was also characterized by MALDI-TOF mass spectrometry.
The thermal studies of PEU1 and PEU2 showed
the stability up to 200–270 °C. The number-average and
weight-average molecular weights were determined for PEU1 and PEU2 by GPC analysis. The weight-average molecular
weight for PEU1 was found to be 5948 with a polydispersity
of 1.1, and PEU2 showed the weight-average molecular
weight as 4224 with a polydispersity of 1.06
Interfacial and Self-Aggregation of Binary Mixtures of Anionic and Nonionic Amphiphiles in Aqueous Medium
Interfacial and bulk properties of sodium dodecyl sulfate (SDS), polyoxyethylene (20) sorbitan monooleate (Tween-80), and their binary mixtures in aqueous medium have been investigated using surface tension, conductance, and fluorescence measurements at different temperatures. The critical micelle concentration (CMC), counterion binding, polarity index, aggregation number, thermodynamics of interfacial adsorption, and micellization are evaluated. The entropic contribution is found to be the predominant factor in micelle formation. The aggregation number and the polarity index of the micelle interior estimated by the pyrene fluorescence technique show interesting temperature dependence. The size and composition of the mixed micelles vary with the total concentration. The micellar compositions, activities of the individual components in the mixed species, and intersurfactant interactions are also estimated following regular solution theory, excess thermodynamic functions, and a molecular thermodynamic model. The surfactant mixtures are found to be nonideal with a lower degree of counterion binding compared to the individual members. Mixed micelles are nonspherical in nature at all temperatures when the mole fraction (α) of the ionic part in mixtures is high but transform to spherical when αSDS is ≤0.50
New Set of Multicomponent Crystals as Efficient Heterogeneous Catalysts for the Synthesis of Cyclic Carbonates
Three new multicomponent
crystals 1a–1c of
Zn(II), Mn(II), and Co(II), respectively, were synthesized by the
reaction of 2,6-bis(hydroxymethyl)pyridine, the respective metal salts,
and sodium benzoate in a 1:1:2 ratio. One component of these multicomponent
crystals 1a–1c is the dicationic 2,6-bis(hydroxymethyl)pyridine
metal complex and the other component is the dianionic tetrabenzoate
complex of the same metal. The complexes were fully characterized
by single-crystal X-ray structure determination. The X-ray structure
of these compounds 1a–1c reveals the formation
of 1D supramolecular chain parallel to the crystallographic b axis via H-bonding interactions between the dicationic
and dianionic parts of the respective compound. The Mn(II) (1b) and Co(II) (1c) complexes show antiferromagnetic
coupling between the two associated metal centers via the H-bonding
interaction pathway. All the three compounds 1a–1c were tested as heterogeneous catalytic systems for the successful
conversion of epoxides to cyclic carbonates in solvent-free condition
under approximately 10 bar of pressure of CO2 and temperature
ranging between 60 and 80 °C along with tetrabutyl ammonium bromide
acting as a cocatalyst. All the three compounds 1a–1c were found to have turnover number more than 1000 for the respective
epoxides except for the conversion of cyclohexene oxide to cyclohexene
carbonate
New Set of Multicomponent Crystals as Efficient Heterogeneous Catalysts for the Synthesis of Cyclic Carbonates
Three new multicomponent
crystals 1a–1c of
Zn(II), Mn(II), and Co(II), respectively, were synthesized by the
reaction of 2,6-bis(hydroxymethyl)pyridine, the respective metal salts,
and sodium benzoate in a 1:1:2 ratio. One component of these multicomponent
crystals 1a–1c is the dicationic 2,6-bis(hydroxymethyl)pyridine
metal complex and the other component is the dianionic tetrabenzoate
complex of the same metal. The complexes were fully characterized
by single-crystal X-ray structure determination. The X-ray structure
of these compounds 1a–1c reveals the formation
of 1D supramolecular chain parallel to the crystallographic b axis via H-bonding interactions between the dicationic
and dianionic parts of the respective compound. The Mn(II) (1b) and Co(II) (1c) complexes show antiferromagnetic
coupling between the two associated metal centers via the H-bonding
interaction pathway. All the three compounds 1a–1c were tested as heterogeneous catalytic systems for the successful
conversion of epoxides to cyclic carbonates in solvent-free condition
under approximately 10 bar of pressure of CO2 and temperature
ranging between 60 and 80 °C along with tetrabutyl ammonium bromide
acting as a cocatalyst. All the three compounds 1a–1c were found to have turnover number more than 1000 for the respective
epoxides except for the conversion of cyclohexene oxide to cyclohexene
carbonate
New Set of Multicomponent Crystals as Efficient Heterogeneous Catalysts for the Synthesis of Cyclic Carbonates
Three new multicomponent
crystals 1a–1c of
Zn(II), Mn(II), and Co(II), respectively, were synthesized by the
reaction of 2,6-bis(hydroxymethyl)pyridine, the respective metal salts,
and sodium benzoate in a 1:1:2 ratio. One component of these multicomponent
crystals 1a–1c is the dicationic 2,6-bis(hydroxymethyl)pyridine
metal complex and the other component is the dianionic tetrabenzoate
complex of the same metal. The complexes were fully characterized
by single-crystal X-ray structure determination. The X-ray structure
of these compounds 1a–1c reveals the formation
of 1D supramolecular chain parallel to the crystallographic b axis via H-bonding interactions between the dicationic
and dianionic parts of the respective compound. The Mn(II) (1b) and Co(II) (1c) complexes show antiferromagnetic
coupling between the two associated metal centers via the H-bonding
interaction pathway. All the three compounds 1a–1c were tested as heterogeneous catalytic systems for the successful
conversion of epoxides to cyclic carbonates in solvent-free condition
under approximately 10 bar of pressure of CO2 and temperature
ranging between 60 and 80 °C along with tetrabutyl ammonium bromide
acting as a cocatalyst. All the three compounds 1a–1c were found to have turnover number more than 1000 for the respective
epoxides except for the conversion of cyclohexene oxide to cyclohexene
carbonate
New Set of Multicomponent Crystals as Efficient Heterogeneous Catalysts for the Synthesis of Cyclic Carbonates
Three new multicomponent
crystals 1a–1c of
Zn(II), Mn(II), and Co(II), respectively, were synthesized by the
reaction of 2,6-bis(hydroxymethyl)pyridine, the respective metal salts,
and sodium benzoate in a 1:1:2 ratio. One component of these multicomponent
crystals 1a–1c is the dicationic 2,6-bis(hydroxymethyl)pyridine
metal complex and the other component is the dianionic tetrabenzoate
complex of the same metal. The complexes were fully characterized
by single-crystal X-ray structure determination. The X-ray structure
of these compounds 1a–1c reveals the formation
of 1D supramolecular chain parallel to the crystallographic b axis via H-bonding interactions between the dicationic
and dianionic parts of the respective compound. The Mn(II) (1b) and Co(II) (1c) complexes show antiferromagnetic
coupling between the two associated metal centers via the H-bonding
interaction pathway. All the three compounds 1a–1c were tested as heterogeneous catalytic systems for the successful
conversion of epoxides to cyclic carbonates in solvent-free condition
under approximately 10 bar of pressure of CO2 and temperature
ranging between 60 and 80 °C along with tetrabutyl ammonium bromide
acting as a cocatalyst. All the three compounds 1a–1c were found to have turnover number more than 1000 for the respective
epoxides except for the conversion of cyclohexene oxide to cyclohexene
carbonate
New Set of Multicomponent Crystals as Efficient Heterogeneous Catalysts for the Synthesis of Cyclic Carbonates
Three new multicomponent
crystals 1a–1c of
Zn(II), Mn(II), and Co(II), respectively, were synthesized by the
reaction of 2,6-bis(hydroxymethyl)pyridine, the respective metal salts,
and sodium benzoate in a 1:1:2 ratio. One component of these multicomponent
crystals 1a–1c is the dicationic 2,6-bis(hydroxymethyl)pyridine
metal complex and the other component is the dianionic tetrabenzoate
complex of the same metal. The complexes were fully characterized
by single-crystal X-ray structure determination. The X-ray structure
of these compounds 1a–1c reveals the formation
of 1D supramolecular chain parallel to the crystallographic b axis via H-bonding interactions between the dicationic
and dianionic parts of the respective compound. The Mn(II) (1b) and Co(II) (1c) complexes show antiferromagnetic
coupling between the two associated metal centers via the H-bonding
interaction pathway. All the three compounds 1a–1c were tested as heterogeneous catalytic systems for the successful
conversion of epoxides to cyclic carbonates in solvent-free condition
under approximately 10 bar of pressure of CO2 and temperature
ranging between 60 and 80 °C along with tetrabutyl ammonium bromide
acting as a cocatalyst. All the three compounds 1a–1c were found to have turnover number more than 1000 for the respective
epoxides except for the conversion of cyclohexene oxide to cyclohexene
carbonate
