| 摘要 |
(H2NCONH)2(I) useful as blowing agent was prepd. in -97% yield by the reaction of excess urea(II) with hydrazine hydrate(III) in ag. soln. at 105-140≦̸C and 1.2-3.5 bar. Thus, e.g., 1634g I, 648.5g II, and 980g H2O were reacted in an autoclave at 122≦̸C, 2.8-2.2 bar for 4hr to give I. During the reaction, by-product NH2 and 5660g H2O vapor were withdrawn, and the H2O was continuously replaced.
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