Gaseous dimethylamine, (CH3)2NH, reacts in air with gaseous nitrous acid, HONO, to yield N-nitroso dimethylamine, (CH.LNNO. Long path infrared spectroscopy is used to monitor these reactions at concentration levels of partsper-million. The measured reaction rate shows that a small degree of nitrosation of dimethylamine vapor might take place during the night in a heavily polluted urban atmosphere. Nitrosation reactions would essentially cease after sunrise because the nitrous acid would be destroyed by photolysis. The N-nitroso dimethylamine vapor is also destroyed by sunlight, the half-life under full sun being about 30 min. By midday any nighttime accumulation of nitrosamine would be rather fully destroyed. Any N-nitroso dimethylamine detected in the air in the afternoon could not be the result of the reaction of precursors. It could only be the result of direct emissions of the pollutant.
The reactions of aminocyclotriphosphazatrienes with dihalogenotriphenyl-and trihalogenodiphenyl-phosphoranes (the Kirsanov reaction) in carbon tetrachloride, chloroform, and benzene have been investigated. By means of these reactions, phosphazen-I '-yl groups can be attached to cyclotriphosphazatriene rings. The co!-irse of the reaction is altered by both the nature of the halogen atoms, and the number of phenyl groups in the phosphorane.The possible mechanisms of these reactions are discussed and their application to the synthesis of a compound obtained by a ring-contraction reaction of octachlorocyclotetraphosphazatetraene with a Grignard reagent is described.
The fundamental objective of many experimental investigations is to characterize and measure the relationships between independent and dependent variables.* Usually, in the systems studied, a large number of factors (independent variables) influence the dependent variable. The customary approach to this type of problem has been to determine the effect of each independent variable one at a time while holding the other independent variables constant or to perform a set of experiments composed of specific combinations of the independent variables. These two techniques are known as the "univariate"' and "factorial" methods,2 3 respectively. However, the results so obtained are, in most cases, dependent on the conditions at which the other independent variables are held constant. One should be cognizant of these interactions when evaluating the results of such an experiment in which the univariate method is utilized. A more accurate appraisal of the interrelationships can be obtained if the effects of several independent variables are investigated simultaneously and in such a way that it is possible to estimate the specific effect of each factor, at different levels of each of the other factors considered in the investigation. Although techniques such as the univariate method and the factorial methods are capable of measuring these effects and interactions, they necessitate an experiment of considerable magnitude. In the last few years, however, a methodology that permits the experimental determination of the effects of several variables simultaneously and subsequent approximation of their response surface has been developed.t This technique has been described as the method of steepest ascent and was conceived and developed by G.E.P. In general, the procedure is as follows: first, the method of steepest ascent is used to determine the conditions for a maximal (or minimal) response of the dependent
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