619-97-6

Kinetics of nitrosation of aniline by N2O4 in donor non-aqueous solvents, e.g. acetonitrile, ethylacetate and a 1:1 v/v mixture of both, have been studied.The reaction is first-order with respect to N2O4 and zero-order with respect to aniline in each of the donor solvents added.The average observed order of k values is ethylacetate (7.195xE-3) > acetonitrile (4.773xE-3) > 1.1 v/v acetonitrile + ethylacetate mixture (3.216xE-3S-1).The variation of k values in the different solvents is interpreted in terms of solvation ability of the solvents.Conductivity measurements and u.v. studies of N2O4 solutions are reported.Both the initial and integral rate methods show that rate-determining step is the one which involves the formation of the nitrosating agent, NO+, from N2O4.Accordingly a mechanism of nitrosation is proposed.

Aryl urea reacts with dioxane-NO2 adduct to give dry aryl diazonium nitrate in high purity and yield.

Gas-solid and solid-solid techniques allow for waste-free and quantitative syntheses in the chemistry of diazonium salts. Five techniques for diazotations with the reactive gases NO2, NO and NOCl are studied. Two types are mechanistically investigated with atomic force microscopy (AFM) and are interpreted on the basis of known crystal packings. The same principles apply to the cascade reactions that had been derived from one-step reactions. Solid diazonium salts couple quantitatively with solid diphenylamine and anilines to give the triazenes. Azo couplings are achieved with quantitative yields by cautious co-grinding of solid diazonium salts with β-naphthol and C-H acidic heterocycles, such as barbituric acids or pyrazolinones. Solid diazonium salts may be more easily applied in a stoichiometric ratio for couplings in solution. Co-grinding of solid diazonium salts with KI gives quantitative yields of various solid aryl iodides. The unavoidable coupling products in salt reactions are completely separated from the insoluble products in a highly benign manner. The solid-state reactions compare favourably with similar solution reactions that produce much waste. The structures of the products are elucidated with IR and NMR spectroscopy and mass spectrometry, while the tautomeric properties of the compounds are studied with density functional calculations at the B3LYP/6-31G* and BLYP/6-31G** levels.

Amines react with PEG-NO2 adduct in nonaqueous condition to give dry arenediazonium nitrates in high purity and high yield.

Amines react with DMF-NO2 adduct under nonaqueous condition to give solid aryl diazonium nitrate in high purity and excellent yield.

Aromatic amines reacted with TBP-NO2 adduct to give dry aryl diazonium nitrate in high purity and yield.

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