a practical and green method for the synthesis of 5h-dibenzo[b,i]xanthene-tetraones and spiro[dibenzo[b,i]xanthene-13,3'-indoline]-pentaones by the condensation of 2-hydroxynaphthalene-1,4-dione with aldehydes or isatins, respectively, in the presence of a catalytic amount of cellulose sulfuric acid (csa) under solvent-free conditions at 100 °c is described. the significant features of this pro...

Solvent-free technique was employed in this work in order to assess the influence of the calcination temperature on the activity of Al-promoted sulfated zirconia. The catalyst was analyzed by XRD and IR-spectrum method, and catalytic activity was examined by esterification reaction of oleic acid. XRD analysis revealed that a decline in the percentage of tetragonal phases of zirconia was observe...

In dentistry, zirconia has been used since the early 1990s for endodontic posts, more recently for implant abutments and frameworks for fixed dental prostheses. Zirconia is biocompatible and mechanically strong enough to serve as implant material for oral implants. Although several zirconia implant systems are available, currently the scientific and clinical data for zirconia implants are not s...

sulfuric acid ([3-(3-silicapropyl)sulfanyl]propyl]ester (saspspe) is employed as a recyclable catalyst for the silylation of hydroxyl groups. a good range of primary, secondary alcohols and phenolic hydroxyl groups were effectively converted into their corresponding trimethylsilyl ethers with hexamethyldisilazane in the presence of catalytic amounts of saspspe at room temperature with short rea...

strong sulfuric acid solutions, and can be measured by a fluorometer.1) Gotelli et al.2) and Shihabi et al.3) have used high-performance liquid chromatography (HPLC) to separate fluorescent derivatives, and have measured cortisol levels in serum and urine. Since the sulfuric acid-induced fluorescence is unstable, it is necessary to inject the reaction mixture into HPLC immediately after the for...

introduction: sugarcane (saccharum officinarum) is widely cultivated in south west of iran for production of sugar. after harvest, a lot of sugarcane tops remain on the farm that can be used to feed ruminants. the total digestible nutrients (tdn) and crude fiber of sugarcane top is about 72% and 39%, respectively. the digestibility of dry matter (54%) and crude protein (39%) of sugarcane top is...