| CuY制备方法对其催化甲醇氧化羰基化活性中心的影响 |
| Effect of Preparation Method on Catalytic Active Center of CuY for Oxidative Carbonylation of Methanol |
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| 摘要: 以Cu(NO3)2为铜源，以NaY和HY分子筛为载体，通过溶液离子交换法和等体积浸渍法制备了不同的无氯CuY催化剂，并进行了气相甲醇氧化羰基化催化活性研究。通过浸渍法制备的催化剂Cu含量为10%，而以NaY和铜氨溶液离子交换制备的催化剂Cu含量只有6.3%，但其催化活性和选择性均较好。通过催化剂的Cu元素分析、低温氮吸附-脱附、XRD、H2-TPR、XPS和TPD等表征表明，溶液离子交换法制备的催化剂，Cu物种以离子的形式高度分散于分子筛骨架结构中，较好地保持了分子筛晶体结构，并对甲醇有较强的吸附能力，催化活性较高，而将等体积浸渍Cu(NO3)2溶液后的HY或NaY分子筛，在400 ℃焙烧过程中，发生了固体离子交换反应，形成了连接于分子筛骨架的Cu2+，但以HY为载体更容易进行固体离子交换，未交换的铜物种以CuO的形式分散到分子筛表面。在600 ℃高温活化中，催化剂中Cu2+可部分还原为活性物质Cu+，但以NaY和铜氨溶液离子交换制备的催化剂Cu2+自还原能力最大。 |
| 关键词: CuY催化剂 制备方法 甲醇 氧化羰基化 |
| 基金项目: |
| Abstract: CuY catalysts were prepared from Cu(NO3)2 solution and NaY/HY zeolite by solution ion-exchange or incipient-wetness impregnation method. Compared to the catalysts with 10% Cu mass prepared by incipient-wetness impregnation, CuY catalyst prepared by ion-exchange of NaY zeolite with copper ammonia solution exhibited the highest catalytic activity and selectivity for the oxidative carbonylation of methanol to dimethyl carbonate. Based on the characterization of CuY catalysts by XRD, Low temperature adsorption-desorption, XPS, TPD, H2-TPR and copper elementary analysis indicate that Cu2+ when exchanged into zeolite framework is likely to be auto reduced to Cu+ and is dispersed more uniquely and the zeolite structure is maintained during high temperature treatment for the catalyst prepared by solution ion-exchange method. Solid-state ion-exchange takes place on the catalyst prepared by impregnation of Cu(NO3)2 on HY or NaY during calcination at temperature of 400 ℃, and HY zeolite is more likely to undergo solid-ion-exchange with Cu2+ than NaY. The unexchanged copper species disperse on zeolite surface as CuO. Some Cu2+ loaded in the catalyst would be auto-reduced to Cu+ when it is calcined at temperature of 600 ℃, but Cu2+ in the catalyst by ion-exchange of NaY zeolite with copper ammonia solution is the easiest one to form Cu+ and the catalyst has very good catalytic activity for oxidative carbonylation of methanol. |
| Keywords: CuY catalyst preparation method methanol oxidative carbonylation |
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| 李 忠,付廷俊,郑华艳.CuY制备方法对其催化甲醇氧化羰基化活性中心的影响[J].无机化学学报,2011,27(8):1483-1490. |
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