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A comprehensive chemostratigraphic study, including evaluation of rare earth elements and trace elements, was conducted to explain the paleoenvironments of the northern margin of the Upper Yangtze Platform. Trace elements, like Ba, U, V, Cu, and Zn, tended to be more abundant in these formations than in the upper continental crust. The authigenic abundances of Al-normalized U and V, as well as the Th/U and V/Sc ratios, were used as indicators of the redox circumstances. In the Nanjiang area, the redox circumstances of the bottom water during the Ordovician–Silurian transition changed from oxic in the Late Katian to slightly anoxic in the Hirnantian and then gradually became anoxic in the Early Rhuddanian. In the Chengkou area, the redox circumstances of the bottom water during the Ordovician–Silurian transition abruptly changed from oxic in the Late Katian to strongly anoxic in the Hirnantian and continued to become more anoxic until the Rhuddanian. The total organic carbon concentrations were well correlated with the redox circumstances of the bottom water. We conclude that the transient hydrothermal activity was not widely distributed during the Late Ordovician–Early Silurian transition, and it might also have been only a local event in the Upper Yangtze Platform. The enrichment in organic matter was mostly sourced from the photic zone and was governed by the redox circumstances of the bottom water.

The kinetics of condensation reaction of methoxyacetone with 2-methyl-6-ethyl aniline catalyzed by NKC-9 cation exchange resin was studied for the first time. The reaction temperature of Schiff base synthesis was determined in the range of 367.15 to 401.15 K by the batch experiments, and influences of reactant molar ratio, temperature, catalyst dosage, and particle size on the ultimate conversion were also studied. The dynamic data were used to be relevant with PH, ER(1), ER(2), and Langmuir Hinshelwood Hougen Watson homogeneity models. Model parameters, including reaction equilibrium constants, activation energy, enthalpy change, entropy change, and rate constants, were solved. The accuracy of the model was validated by means of both experimental proofs and standard deviation between the predicted and experimental data. Finally, a series of characterization tests such as Fourier transform infrared spectroscopy, X-ray diffraction, and polarizing microscopy were performed to investigate the structure and properties of NKC-9.