Résumé
This work presents the outcome of a research project to evaluate the rates of heavy metals deposition over the heaviest industrial area in Egypt. Heavy metals such as lead, cadmium, nickel and zinc were analysed in both soluble and insoluble fractions of dustfall. The results show high rates of heavy metals deposition over the area. The highest rates of heavy metals deposition were found at locations close to iron and steel company and lead and zinc smelter. One of the intersting findings of this work is that the ratio between water soluble and insoluble metals were significantly different from one location to the other and also between the different investigated metals. Several other conclusions are included
Sujets)
Industrie , Déchets industriels , Plomb , CadmiumRésumé
Although many reagents are available to affect the conversion of aldehydes to nitriles, the majority is electrophilic in character, or require acidic conditions. Recently, thermal d composition [Scheme 1] of aldehyde derivatives in a concerted way offers an alternative for this conversion, in cases where thermal liability or inviolability does not offer an additional obstacle. In the second reaction [B], reactions due to radical fragmentation were the main reasons for the decreased yield of nitriles, since these produce in addition ozines and consequently ethylene. In order to drive the reaction completely towards the concerted pathway, we investigated the thermal fragmentation of N[1] benzoylphenylhydrazones, where steric factors may give the correct orientation for the transition state required for the concerted pathway and that leading to the exclusive formation of nitriles and benzanilide [Scheme2] In this case, we found that the pyrrolysis of the hydrazones Ia-f yields as anticipated mainly the desired nitrile III and benzanilide, however the pyrrolysis occurred only above 260 degree [230 - 320degree] and the yields of the nitriles range from 50-70 percent