Abstract: STUDIES ON REACTION KINETKTICS OF NITROUS ACID WITH n-BUTYLALDEHYDE AND Ap（Ⅵ）WU YUPING ;LIN ZHANGJI; CHEN YAOZHONG（China Institute of Atomic Energy,P.O. Box 275（26），Beijing 102413）ABSTRACT The kinetics of the reaction of nitrous acd with n-butylaldehyde and neptunium（Ⅵ）is studied and the results in different reaction systems are obained：（1）in system of nitrous acid withn-butylaldehyde，when t=20℃ and ion strengh I=2．0mol/kg，the rate constant k_1=0．761~2／（mol~2·min ）；（2） in system of nitrous acid withNp（Ⅵ），when and I=1．0mol/kg，theapparent rate constant；（3）in system of nitrous acid and n-butylaldehydewith Np（Ⅵ），when and I=1．0mol/kg，the apparent rate constant ．The results show that the nitrous acid has abigger reaction rate with Np（Ⅵ）than with n-butylaldehyde or n-butylaldehyde with Np（Ⅵ）. Key words Nitrous acid n－Butylaldehyde Neptunium Kinetics of reduction