Reactions of Benzyl Aryl Sulfides with Excess Active Halogen Reagents

1,2,3-Tribromopyrrolo[1,2-b][1,2]benzothiazin-10-one (2) is produced from 2-[2-(benzylthio)benzoyl]pyrrole (1) when treated with excess (5 equiv) NBS in CHCl3. With NCS, a mixture is obtained in which di- and trichloropyrrolo[1,2-b][1,2]benzothiazin-10-ones are present. If ethanol is present in the NCS reaction, compound 4 is formed as the major product. Further, compound 3 is also formed by the reaction of compound 1 or the corresponding disulfide with excess SOCl2. A novel route to alkyl arenesulfinic esters is also reported. Treatment of a benzyl aryl sulfide with excess (5 equiv) NCS in the presence of an n-alkyl alcohol (7 equiv) produces an n-alkyl arenesulfinic ester in good yield. An arenesulfonyl chloride is the major product in the presence of benzyl alcohol

Media 1: Experimental observations of thermo-optical bistability and self-pulsation in silicon microring resonators

Originally published in JOSA B on 01 February 2014 (josab-31-2-201

High-Barrier Oxidized Cellulose Nanofibril/Chitosan Coating for Functional Food Packaging Materials

With the continuous introduction of plastic restriction policies by the government and the continuous enhancement of people’s awareness of environmental protection, the demand for food packaging materials has also continued to increase, and the research and development of biodegradable green packaging materials has become the frontier research direction in the field of food packaging materials. In this study, nanocellulose-based coating solution with high barrier properties was prepared from oxidized cellulose nanofibrils (OCNFs) via sodium periodate and compounded with chitosan solution (CTS) and then coated on the substrate paper. Experiments have found that when the mass fraction of the OCNF in the OCNF/CTS coating solution is 0.5%, the coated paper exhibits the optimum comprehensive performance. The oxygen transmission rate of the OCNF/CTS-coated paper dropped to 1.732 × 10–11 cm3·cm/cm2·s·Pa, and the water vapor transmission rate reduced to 2.236 × 10–12 g·cm/cm2·s·Pa. This is due to the fact that the OCNF cross-linking with CTS improves the compactness of the paper surface layer, which in turn enhances its barrier. These findings suggested that the OCNF/CTS-coated paper has great potential and prospect in the application of food packaging materials, which provide a possible positive example of barrier coating in the packaging field