溴代烷烃与活性氮的反应发光研究

Chemiluminescence of Alkyl Bromides Reaction with Active Nitrogen

在流动余辉装置上,利用N2空心阴极放电制备活性氮,研究了活性氮与溴代烷烃(CHBr3、CH2Br2、C2H5Br、C4H9Br)反应的化学发光.上述所有反应中,在550～750nm波段均观察到了较强的NBr(b1Σ+→X3Σ-)跃迁发射谱.同时在活性氮与CHBr3和CH2Br2的反应中,在流动管下游还观察到了CN(A2仔,B2仔→X2撞+)的发射谱.验证性的实验表明,激发态NBr(b1Σ+)是由二步过程形成:N(4S)与溴代烷烃反应生成NBr(X3Σ-),再通过N2(A3Σu+)分子能量转移到激发态NBr(b1Σ+);而激发态的CN是通过N(4S)+CBr→CN(A,B)+Br过程形成的.

Active nitrogen has been prepared by hollow-cathode discharge of N-2 in a flowing afterglow system. Strong emission spectra of NBr(b(1)Sigma(+)-> X-3 Sigma(-)) have been observed when alkyl bromides (CHBr3, CH2Br2, C2H5Br, C4H9Br) are added to a stream of active nitrogen. In addition, weak CN(A(2)pi, B-2 pi -> X-2 Sigma(+)) emission spectra have been detected only in the case of CHBr3 or CH2Br2 as reagents. Some tentative experiments show that the electronically excited NBr(b(1)Sigma(+)) is formed by mechanism of metastable N-2(A(3)Sigma(+)(u)) electronic-to-electronic energy transfer from ground state NBr(X-3 Sigma(-)), which is from the reaction of N(S-4) with alkyl bromides. The excited CN (A(2)pi, B-2 pi) comes from the reaction of N(S-4) with CBr formed due to CHBr3(or CH2Br2) dissociation by N2 (A(3)Sigma(+)(u)).