640-67-5Relevant articles and documents
Preparation and thermal dehydration of manganese(II) dicarboxylate hydrates
Suzuki, Yukihiko
, p. 155 - 170 (1995)
Manganese(II) dicarboxylate hydrates Mn[OOC(CH2)nCOO] . xH2O have been prepared by the addition of MnCO3 powder or concentrated MnSO4 solution to aqueous solutions of the corresponding dicarboxylic acids. The crystalforms of the precipitated compounds were observed by optical microscopy . The crystals were obtained either as ellipsoidal, short rods or very small uneven particles. The crystals were different from those of the dicarboxylic acids. The dicarboxylates obtained were characterized by X-raydiffraction analysis and IR spectral measurement. The thermal dehydrati ons of the Mn(II) dicarboxylate hydrates were investigated by TG-DTA. The temperatures at which dehydration occured were taken as a measure of the strength of the Mn-OH2 bond, and these were found to vary with increasing number of CH2 groups in the dicarboxylic acid. The kinetic parameters for the dehydration were calculated by employing a computation method. The three-dimensional diffusion model is found to be the best for describing the kinetic results for the main reaction.
Thermal and electrical properties of manganese (II) oxalate dihydrate and cadmium (II) oxalate monohydrate
Nikumbh,Athare,Pardeshi
, p. 187 - 192 (1999)
The thermal decomposition of MnC2O4·2H2O and CdC2O4·H2O have been studied by two probe direct current electrical conductivity measurements under the atmospheres of static air, dynamic dry n
Dehydration reaction of manganese(II) oxalate dihydrate in the solid state: New method in the study of non-isothermal kinetics
Pan,Guan,Feng,Wu,Li
, p. 877 - 884 (1999)
A new method was proposed for determining the most probable mechanism function of a solid phase reaction. According to Coats-Redfern's integral equation Eβ→0 was calculated by extrapolating β to zero using a series of TG curves with different heating rates. Similarly, Eα→0 was calculated according to Ozawa's equation. The most probable mechanism function of the solid phase dehydration of manganese(II) oxalate dihydrate was confirmed to be G(α)=(1-α)1/2 by comparing Eα→0 with Eβ→0.
Point defects of tephroite. I: The electrical conductivity of Mn2SiO4
Stueber, Christoph,Laqua, Wolfgang
, p. 197 - 218 (1998)
The electrical conductivity σ of single crystalline Mn2SiO4 (tephroite) grown from the melt, was investigated by impedance spectroscopy between 1101 and 1197°C as function of oxygen activity within the range ～10-16 ≤ ao2 ≤ 0.21 (air). Mn2SiO4 is n-conducting within the low and p-conducting within the high oxygen-activity regime, independent whether the sample are buffered against MnO or MnSiO3. Based on our experimental results we propose a point-defect model the majority defects of which are vacancies in the manganese sublattice V″Mn, Mn3+-ions on Si-lattice sites Mn′Si, holes h' (= Mn'Mn) and electrons e′. Unlike Fe2SiO4 (fayalite), wherein according to thermogravimetric results of Nakamura and Schmalzried [1] associates {Fe'FeFe′Si}x exist, our defect model works without postulating the analogous species {MnMnMn′Si}x to exist in tephroite. We drew this conclusion from the 1/5.5-power law which is followed by our σ-ao2-plots measured on stoichiometric tephroite in the high-ao2, regime, whereas Nakamura and Schmalzried derived an 1/5.0 power law from their measurements in the range of similar oxygen activities on likewise stoichiometric fayalite. The equilibrium constants for formation reactions of the aforementioned defects, which emerged from our experiments were used to depict Kroeger-Vink diagrams ; they describe the dependence of defect concentrations on oxygen activities for both MnO resp. MnSiO3 buffered tephroite. by R. Oldenbourg Verlag, Muenchen 1998.
Textural and capacitive characteristics of MnO2 nanocrystals derived from a novel solid-reaction route
Yuan, Anbao,Wang, Xiuling,Wang, Yuqin,Hu, Jie
, p. 1021 - 1026 (2009)
Nanostructured manganese dioxide (MnO2) materials were synthesized via a novel room-temperature solid-reaction route starting with Mn(OAc)2·4H2O and (NH4)2C2O4·H2O raw
Very fast crystallisation of MFe2O4 spinel ferrites (M = Co, Mn, Ni, Zn) under low temperature hydrothermal conditions: A time-resolved structural investigation
Dolcet, Paolo,Diodati, Stefano,Zorzi, Federico,Voepel, Pascal,Seitz, Christoph,Smarsly, Bernd M.,Mascotto, Simone,Nestola, Fabrizio,Gross, Silvia
, p. 2257 - 2268 (2018/05/29)
MFe2O4 spinel ferrites (M = Co, Mn, Ni, Zn) were synthesised through a low-temperature aqueous route combining co-precipitation of oxalates and hydrothermal treatment at 135 °C. With the objective of gaining a deeper understanding of the structural evolution of the compounds to crystalline materials during the synthetic process, samples were prepared within different reaction times, showing in most cases a fully crystalline habit already after short treatment times. The resulting solids were characterised through several state-of-the-art analytical techniques, both on the atomic (XAS) and mesoscopic (XRPD, SAXS) scales. In parallel, temperature-programmed characterisation was carried out to investigate the evolution of the compounds during the heating process.
Catalyst-free microwave-promoted one pot synthesis of 2-aryl benzoxazoles using MnO2 nanoparticles as a convenient oxidant under mild condition
Naeimi, Hossein,Rouzegar, Zahra,Rahmatinejad, Soraya
, p. 4745 - 4758 (2017/07/22)
Abstract: An efficient and facile protocol for one pot synthesis of a series of 2-aryl benzoxazoles through coupling of o-aminophenol with aromatic aldehydes under microwave irradiation in the presence of MnO2 nanoparticles as oxidant reagent was demonstrated. The MnO2 nanoparticles were prepared via a solid-state chemical reaction technique. The structure of oxidant was assigned by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The target molecules were obtained in good to high yields, high purity and short reaction times. The pure products were identified and characterized by physical and spectral data such as; melting point, IR, 1H NMR and 13C NMR. Graphical Abstract: An efficient and facil protocol for one pot synthesis of a series of 2-aryl benzoxazoles through coupling of o-aminophenol with aromatic aldehydes under microwave irradiation in the precense of MnO2 nanoparticles as oxidant reagent was demonstrated.
