常压和真空下CS2的光氧化反应

利用原位FTIR、XPS 和GC-MS等技术手段,研究了常温紫外光辐照下常压及真空状态中,CS₂的光氧化反应.结果表明,常压及真空状态下CS₂光氧化反应的产物均为COS、SO₂、CO 和 CO₂,反应均遵循表观一级反应动力学规律,但中间产物COS的浓度变化有较大的差异.常压下COS浓度先迅速增大,然后减少; 真空条件下COS浓度增加到常压下COS浓度的 1/10后基本持平,然后逐渐减小,整个变化趋势缓慢; 2种条件下CS₂的半衰期分别为31.6 s和39.8 s, 中间产物COS降解 98% 所需时间分别为 55 min和22 min.在相同的光照条件下,O₂浓度的增加有助于CS₂光氧化反应的进行.以CS₂光氧化中间产物COS为初始物的光氧化反应主要产物为CO₂和SO₂,后者可以进一步被氧化为SO2-4.适量增加O₂的浓度可以促进COS光氧化反应的进行,但O₂的浓度增加至一定程度后反应速率基本保持恒定.以上结论对揭示CS₂和COS的源和汇以及全球S物质循环具有重要价值.

Photooxidation of CS2 Under Ambient Pressure and Vacuum Condition

With the radiation of UV light, the photooxidation of CS₂ was studied under ambient pressure and vacuum condition.By means of in-situ FTIR,XPS and GC-MS, it is confirmed that the products of the reaction are COS,SO₂,CO and CO₂. The reaction is apparent first-order. Under ambient pressure and vacuum condition the concentration of the intermediate product COS varies tremendously.Under ambient pressure the concentration of COS increases sharply and then decreases gently.While under vacuum condition COS rose only up to 1/10 that of the ambient pressure, and remained invariable until finally vanished slowly.Under ambient pressure and vacuum condition, the half life time of CS₂ was 31.6 s and 39.8 s, and it took 55 min and 22 min to degrade 98% of COS respectively.Oxygen promotes CS₂ photooxidation.The main products of the photooxidation of COS, which is an important intermediate of the photooxdiation of CS₂, are CO₂ and SO₂.In addition, SO₂ could be further oxidized into SO₄^2-.Increasing appropriate amount of oxygen could promote the photooxidation activity of COS. However, the rate constant remains invariable when the oxygen is overloaded.