| 摘要: |
| 我国面临巨大HFCs制冷剂销毁压力，亟需探究高效且温和的HFCs制冷剂降解方法。本文结合实验与量子化学计算，以典型HFCs制冷剂HFC-134a为对象，以降解率为主要衡量标准，探究制冷剂降解的高效途径。从量子化学的角度，探究了HFC-134a自热分解与氧化热解条件下的反应路径，在两条路径下，均易产生CHF=CF2与HF等可检测到的稳定产物。自热分解过程中，第一步化学键的断裂是决速步骤。氧化热解路径相较自热分解路径，反应能垒低，有利于反应快速发生。从实验的角度，发现在240 - 360℃温度范围内，随温度的提高，HFC-134a的降解率由11%提高到66%，通过反应动力学常数拟合计算，得到HFC-134a的指前因子为7471.04 s-1，表观反应活化能为54.16 kJ/mol，与模拟计算所得化学反应能垒相吻合。 |
| 关键词: 反应能垒 表观反应活化能 氧化热解 密度泛函方法 HFC-134a |
| DOI： |
| 投稿时间：2022-08-10 修订日期：2022-08-30
录用日期：2022-08-31 |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| Mechanism and Experimental Studies of HFC-134a Oxidative Decomposition Mechanism |
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| Abstract: |
| There is a huge pressure of HFCs refrigerant destruction in China, therefore, it is urgent to explore efficient and mild HFCs refrigerant degradation methods. In this paper, combined with experiments and quantum chemical calculations, the typical HFCs refrigerant HFC-134a is taken as the object, and the degradation rate is the main criteria to explore the high-level pathway of refrigerant degradation. From the perspective of quantum chemistry, the reaction paths of HFC-134a under the conditions of pyrolysis and oxidative decomposition are explored. Under both paths, detectable stable products such as CHF=CF2 and HF are easily produced. During pyrolysis, the first step of chemical bond cleavage is the rate-determining step. Compared with the pyrolysis path, the oxidative decomposition path has a lower reaction energy barrier, which is conducive to the rapid occurrence of the reaction. From the experimental point of view, it was found that the degradation rate of HFC-134a increased from 11% to 66% in the temperature range of 240 - 360 °C with the increase of temperature. By fitting and calculating the kinetic constant of the reaction, the pre-exponential factor (A) of HFC-134a is 7471.04 s-1, and the activation energy (Ea) is 54.16 kJ/mol, which is consistent with the chemical reaction energy barrier calculated by the simulation. |
| Key words: the chemical reaction energy barrier the activation energy(s) oxidative decomposition DFT HFC-134a |
