Chemical Kinetics of Disproportionation Decomposition of tert-Butyl Hydroperoxide Catalyzed by Buserite-type Manganese Oxides

LU Shu-Pei, FENG Li-Li, QI Lin, WANG Li-Li, QI Xing-Yi
2016 Journal of Inorganic Materials  
摘 要: 以 MnSO 4 ·H 2 O 为锰源, K 2 S 2 O 8 为氧化剂, 制备了 4 种含有不同层间阳离子(Me, Me  Mg 2+ 、 Co 2+ 、 Ni 2+ 、 Cu 2+ ) 的 buserite 型氧化锰(Me-buserites)。采用 X 射线衍射(XRD)、电感耦合等离子体原子发射(ICP-AES)和 N 2 吸附-脱 附(BET)对制成 Me-buserites 的晶相结构、元素组成和比表面积进行了表征。采用 25 mL 间歇式玻璃反应器, 考察 了 Me-buserites 催化叔丁基过氧化氢歧化分解反应动力学。反应动力学分析表明: 反应底物叔丁基过氧化氢浓度项 反应级数为 2, Me-buserites 形式浓度项反应级数为 1, 总反应级数为 3; 表观活化能为 56~125 kJ/mol。与动力学拟 合结果相一致的反应机理是由前置平衡和速控两个反应步骤组成。基于 338 K 反应温度准二级速率常数和 0.5 h 反应时 间累积 O 2 体积决定的活性顺序为
more » ... erite; 在选定反应条件下, 所有 Mebuserites 的叔丁醇选择性均为 100%。 关 键 词: Buserite 型氧化锰; 叔丁基过氧化氢; 叔丁醇; 歧化分解; 反应动力学 中图分类号: O643 文献标识码: A Abstract: The series of four buserite-type layered manganese oxides (Me-buserites) with different interlayer cations (Me, Me  Mg 2+ , Co 2+ , Ni 2+ , Cu 2+ ) were synthesized by using both MnSO 4 ·H 2 O as Mn source and K 2 S 2 O 8 as oxidant. The as-synthesized Me-buserites were characterized by X-ray diffraction (XRD), inductively coupled plasma-atomic emission spectrometry (ICP-AES) and N 2 adsorption-desorption (BET), in order to determine their crystal phases, elemental compositions and specific surface areas, respectively. In a 25 mL batch glass reactor, the disproportionation decomposition of tert-butyl hydroperoxide was kinetically investigated with the above Me-buserites as catalysts. The kinetic analyses show that the rate law established herein is second order in tert-butyl hydroperoxide, first order in Me-buserites and then third order overall, and that the apparent activation energy ranges from 56 kJ/mol to 125 kJ/mol. In accordance with the kinetic fittings, the proposed mechanism comprises two elementary reaction steps: pre-equilibrium step and rate-determining step. In terms of the pseudo-second-order rate constant and the half an hour-accumulated O 2 volume (both obtained at 338 K), the activity follows the order of Cu-buserite > Mg-buserite > Ni-buserite > Co-buserite. And a 100% selectivity towards tert-butyl alcohol is achieved over all the Me-buserites un-第 1 期 卢书培, 等: Buserite 型氧化锰催化叔丁基过氧化氢歧化分解反应动力学 15 der selected reaction conditions.
doi:10.15541/jim20150295 fatcat:puxz7sopwzh3xlzxz4pm37iani