化学化工专业英语.ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,*,单击此处编辑母版标题样式,*,*,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,*,化学化工专业英语,化学化工专业英语化学化工专业英语 As we all know chemical pollution is global problem，How to reducing chemical pollution？,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 progress could be made in organic reactions in water,which have great potential in reducing chemical pollution.,What is more,replacing the distilled water with tap water had no influence on the allylations,it supply a way to do the organic experiment in the water,Conclusion,In conclusion,the result demonstrated that an efficient and clean synthesis for allylation in distilled or tap water with high product yields can be developed.Nano-tin particles were applied in the allylations of aldehyde and ketone,and satisfactory results were obtained.,Thank you,谢谢大家！,结 语,