METHOD OF PREPARING 3 (5) METHYLPYRAZOLE Russian patent published in 1997 - IPC

FIELD: agriculture. SUBSTANCE: present invention describes method of preparing 3 (5) methylpyrazole derivatives of general formulae 1a and 1b given in the claims, wherein R is hydrogen, alkyl containing 1-6 carbon atoms, unsubstituted or substituted phenyl by reacting diacetylene with hydrazine of general formula II: RHN-NH₂ (II), wherein R is as defined above, or hydrate thereof. The claimed method comprises reacting diacetylene containing stream separated by absorption from the resulting from cracking gas formed in the production of acetylene with hydrazine of formula II or hydrate thereof. Said 3 (5) methylpyrazole derivatives are useful as inhibitors of nitrification of ammonium-containing fertilizers. EFFECT: more efficient preparation method. 15 cl