Specificity of the Reaction of 1,1‐Dimethylhydrazine with Phenyl Isocyanate.

Abstract

Urea derivatives Urea derivatives Q 0640Specificity of the Reaction of 1,1-Dimethylhydrazine with Phenyl Isocyanate. -The reaction of phenyl isocyanate with a large excess of 1,1-dimethylhydrazine gives 4-phenylsemicarbazide (III) as the major product. At other reactant ratios, biuret-like structures such as (IV) and (V) are formed. -(SAVEL'EV, Y. V.; KHRANOVSKII, V. A.; VESELOV, V. Y.; GREKOV, A. P.; SAVEL'EVA, O. A.; Russ.

Isothiocyanates as derivatization reagents in the determination of 1, 1-dimethylhydrazine by gas chromatography coupled with mass spectrometry

“…10 The chromatographic behavior is characterized by the efficient resolution of thiosemicarbazides and an excess of the derivatization reagents, which improves the quantita tive determination of DMH due to the increased measure ment accuracy of the peak areas of the DMH derivative, which is not overlapped with the chromatographic peak of the derivatization reagent (Fig. 1).…”

“…For instance, to obtain the equimolar addition product capa ble of acting as an analytical form, it is necessary to use a threefold excess of DMH. 10 Because of this fact and formation of oligoureas, PIC cannot be used in the deter mination of DMH. Another substantial disadvantage of PIC is its non selectivity to N and O nucleophiles, such as secondary amines, alcohols, thiols, carboxylic acids, hydroxylamines, and water, which impedes the determi nation.…”

Synthesis and structural peculiarities of 1,1‐dimethylhydrazine‐based polyurethanes

“…However, the treatment of PP with DMH at various nonequimolar ratios does not lead to crosslinking, and PUs soluble in organic solvents are formed 5. To explain these results, a model reaction of the formation of urethane between DMH and phenylisocyanate (PhIC) has been studied 6. This reaction should result in the formation of 1,1‐dimethyl‐4‐phenylsemicarbazide [Fig.…”

“…1(I)] in accordance with classical conceptions of the interactions of isocyanates with hydrazides (or amines). However, an investigation of the chemical structure of the reaction products (at various reagent ratios) by IR and NMR spectroscopy showed the fallacy of this assumption 6. The reaction of DMH and PhIC was not completed with 1,1‐dimethyl‐4‐phenylsemicarbazide as the main product, and compounds of biuretlike structures [Fig.…”

“…Only in the case of a considerable excess of DMH with respect to PhIC was 1,1‐dimethyl‐4‐phenylsemicarbazide [Fig. 1(I)] obtained as the main product 6…”