Beijing University of Technology

About: Beijing University of Technology is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: Microstructure & Computer science. The organization has 31929 authors who have published 31987 publications receiving 352112 citations. The organization is also known as: Běijīng Gōngyè Dàxué & Beijing Polytechnic University.

Electrochemical Minisci-type trifluoromethylation of electron-deficient heterocycles mediated by bromide ions

Abstract: An electrochemical methodology for the Minisci-type trifluoromethylation of electron-deficient heterocycles mediated by cheap and easily available bromide ions has been developed. By virtue of the in situ generated sulfonyl hypobromite intermediate, the CF3 radical can be regulated and controlled at a low concentration, thereby improving the reaction efficiency over direct electrolysis. Also, this indirect electrochemical process is performed in a beaker-type undivided cell under galvanostatic conditions, without using external expensive supporting electrolytes. This protocol provides an alternative electrochemical trifluoromethylation methodology for the late-stage functionalization of biologically important molecules.

Free Radical Graft Copolymerization Strategy To Prepare Catechin-Modified Chitosan Loose Nanofiltration (NF) Membrane for Dye Desalination

Abstract: In this study, a novel free radical graft copolymerization strategy was applied to prepare the catechin-modified chitosan loose nanofiltration (NF) membrane for dye desalination. First, catechin, the eco-friendly natural material, was grafted onto chitosan through a free radical reaction and self-cross-linking. Second, the catechin-grafted-chitosan conjugates were assembled onto the surface of the hydrolyzed polyacrylonitrile (HPAN) ultrafiltration (UF) membrane. Finally, the prepared membrane was characterized by FT-IR, XPS, SEM, AFM, electrokinetic analyzer, and contact angle goniometer. The results showed that the prepared membrane exhibited a high rejection for dyes (i.e., 99.6% for congo red, 98.7% for acid fuchsin, and 98.5% for crystal violet) and a low retention for inorganic salts (i.e., 4.8% for Na2SO4, 12.5% for NaCl, 15.8% for MgSO4, and 16.2% for MgCl2). The Na2SO4 rejection, especially, was 2–3 times lower than that of the reported loose NF membranes. Meanwhile, a high removal rate of 82% fo...