化学化工专业英语分析.ppt

09级化学类 演讲人：周国新 Theme：Application of Tin and Nanometer Tin in Allylation of Carbonyl Compounds in Tap Water As we all know chemical pollution is global problem ，How to reducing chemical pollution？ Introduction With the development of industrialization, organic chemists have been confronted with a new challenge of finding novel methods in organic synthesis that can reduce and finally eliminate the impact of volatile organic solvents and hazardous toxic chemicals on the environment. So, using aqueous media to perform organic reactions has attracted considerable interest recently because water is considered to be a safe and environmentally benign solvent The first of experiment step Firstly ,to initiate the experiment, a mixture of benzaldehyde, allyl bromide, and the metal powder in 3 mL of distilled or tap water without any coreagent or cosolvent was stirred at room temperature. The second of experiment step After about 24 h, the reaction was monitored by TLC, and the reaction mixture was extracted with ether; subsequently, the ether extract was washed with water and dried with magnesium sulfate The third of experiment step After removal of the solvent, the crude product was obtained. The yield of the allylation product was measured by 1H NMR The metals used varied from Fe to Sn, and the reaction results are listed in Table 1. This study demonstrated that the unusual phenomenon of nanometer tin-mediated allylation was caused by properties of nanometer tin particles. The smaller the radius of tin nanometer particles, the greater the ratio of surface to volume, which leads to a large increase of atoms on the surface and an abundance of suspended and unsaturated bonds and so on, affected by the unsaturated coordination. All these make the surface of the tin nanometer particle more active and enhance the reaction selectivity. What is more, replacing the distilled water with tap water had no influence on the allylations. Our work showed us that substantial p