Bulletin of the Korean Chemical Society

Korean Chemical Society (대한화학회)
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Kinetic and Molecular Orbital Stuides on the Reaction of 5-nitrofurfural Hydrazone Formation

  • Lee, Kyung-Hee (Department of Chemistry, Teacher's College, Kyungpook National University) ;
  • Jee, Jong-Gi (Department of Chemistry, Teacher's College, Kyungpook National University)
  • Published : 1985.10.20
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Abstract

Kinetic measurements of the 5-nitrofurfural-hydrazine reaction in various pH ranges of aquous solution were carried out by ultraviolet spectrophotometry at $25^{\circ},\;35^{\circ}\;and\;45^{\circ}C$. The observed rate of the reaction varies with the change in pH, which gives characteristic "bell-type" rate acidity profile. The maximum rate is shown in the vicinity of pH 4. This reaction procceds with rate-determining attack of hydrazine on the 5-nitrofurfural at low pH and undergoes a change in rate-determining step to dehydration of the addition intermediate as pH increases. The reaction has a "reactant-like transition state" which precedes intermediate in low pH and "product-like transition state" which follows it in neutral pH. The geometry of 5-nitrofurfural-hydrazine intermediate was estimated with PCILO method associated with CNDO/2 scheme.

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