氘反同位素效应是合理阐明过渡金属催化剂上氨合成催化反应机理的重要实验依据之一.在N_2/H_2(或D_2)体积比1/3,0.2MPa,633~733K和GHSV=24 000或12 000h~(-1)的条件下,检测到了Ru基(纯Ru,Ru/γ-Al_2O_3,K-Ru/γ-Al_2O_3,Ru/MgO,K-Ru/MgO和Ba-Ru/MgO)和Fe基(纯Fe和A110-3)催化剂上强的氘反同位素效应(r_D/r_H)≈2),其数值随催化剂和反应温度的变化而变化.这可能是动力学同位素效应与热力学同位素效应二者相互强竞争的结果.
The deuterium mverse isotopic effect (DHE) is important for the clarification of the ammonia synthesis mechanism over transition metal catalysts. We investigated the DIIE over Ru-based and Fe-based catalysts including pure Fe, multi-promoted fused Fe, pure Ru, Ru/γ-Al_2O_3, K-Ru/γ-Al_2O_3, Ru/MgO, K-Ru/MgO, and Ba-Ru/MgO under the reaction conditions of N_2/H_2 (or D_2) volume ratio = 1/3, 0.2 MPa, 633-733 K, and GHSV = 24 000 and 12 000 h~(-1). A strong DIIE (r_D/r_h of about 2) was observed over the above catalysts. The trend of the DHE with catalysts and temperature indicated a strong competition between the dynamic and thermodynamic factors.
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