Pyrolysis Kinetic Analysis of Sequential Extract Residues from Hefeng Subbituminous Coal Based on the Coats-Redfern Method.

Sequential extract residues (R , = 1, 2, 3, 4, and 5) were obtained from Hefeng acid-washing coal (HF) by petroleum ether, carbon disulfide, methanol, acetone, and isometric carbon disulfide/acetone mixture, sequentially. Pyrolysis behavior of the residues was determined using thermogravimetry analysis. The Coats-Redfern method with different reaction orders was used to analyze the pyrolysis kinetic of each sample, and the kinetic parameters, including correlation coefficient ( ), activation energy (), and pre-exponential factor (), were calculated.

Analysis of Pyrolysis Performance and Molecular Structure of Five Kinds of Low-Rank Coals in Xinjiang Based on the TG-DTG Method.

Taking five coal samples (FCSs) in Xinjiang as the research object, characterizations such as proximate analysis, ultimate analysis, Fourier transform infrared (FTIR), and thermogravimetry-differential thermal analysis (TG-DTG) were carried out. The Coats-Redfern model was used to simulate pyrolysis kinetics of FCSs under different reaction orders (ROs). The results showed that except for HSBC, the of the other four coal samples are all higher than 0.

Chiral Phosphoric Acid-Catalyzed C6 Functionalization of 2,3-Disubstituted Indoles for Synthesis of Heterotriarylmethanes.

The direct regio- and enantioselective C6 functionalization of 2,3-disubstituted indoles with azadienes has been developed using chiral phosphoric acid as catalyst, providing a convenient approach to synthesize the optically active heterotriarylmethanes with excellent yields, broad substrate scope, and up to 98% ee. Mechanistic studies revealed that -alkylation of 2,3-disubstituted indoles with azadienes would be reversible, and enantioselective C6 functionalization could be enabled.