介孔调变对CuY催化剂甲醇氧化羰基化反应活性的影响

发布时间：2018-08-05 20:38

【摘要】：碱溶液处理NaY分子筛形成的介孔有利于反应物及产物分子的扩散,调节碱溶液浓度可控制Y分子筛中的介孔结构,通过溶液离子交换法制备CuY催化剂,研究了NaY分子筛介孔结构调变对CuY催化剂催化甲醇氧化羰基化反应活性的影响。通过BET、~(29)Si-NMR、XRD、NH_3/CO-TPD、H_2-TPR和TEM等表征及催化活性分析表明,在碱溶液处理过程中,NaY分子筛骨架中的Si(0Al)和Si(1Al)原子被优先脱除,且笼结构坍塌使得临近超笼连接,逐步形成直径为3.47~3.66 nm,孔容介于0.142~0.226cm~3·g~(-1)的介孔,在提高反应物分子和产物分子扩散性能的同时,提高了活性物种的可接近性。随着碱液浓度的增加,CuY催化剂的催化活性先升高后降低。当碱液浓度为0.2 mol·L~(-1)时,NaY分子筛介孔直径为3.47 nm,孔容达到最大(0.226 cm~3·g~(-1)),相应CuY催化剂DMC的时空收率、选择性和甲醇转化率分别达到204.0 mg·g~(-1)·h~(-1)、67.8%和14.0%,活性最佳。
[Abstract]:The mesoporous formation of NaY molecular sieve treated with alkali solution is beneficial to the diffusion of reactants and product molecules. The mesoporous structure in Y molecular sieve can be controlled by adjusting the concentration of alkali solution. The CuY catalyst is prepared by solution ion exchange method. The effect of mesoporous structure modification of NaY molecular sieve on the catalytic activity of CuY catalyst for oxidative carbonylation of methanol was studied. The characterization and catalytic activity analysis of BET29Si-NMR-XRDX NH3 / CO-TPDN H2-TPR and TEM show that the Si (0Al) and Si (1Al) atoms in the skeleton of nay molecular sieve are removed preferentially during alkali solution treatment, and the collapse of cage structure leads to close supercage connection. A mesoporous medium with a diameter of 3.47 ~ 3.66 nm and pore volume of 0.142~0.226cm~3 g ~ (-1) was gradually formed. The diffusion properties of reactants and products were improved, and the accessibility of active species was improved. The catalytic activity of CuY catalyst firstly increased and then decreased with the increase of alkali concentration. The mesoporous diameter of nay molecular sieve was 3.47 nm when the concentration of alkali solution was 0.2 mol L ~ (-1), and the pore volume reached the maximum (0.226 cm~3 g ~ (-1),) CuY catalyst DMC yield, selectivity and methanol conversion reached 204.0 mg g ~ (-1) h ~ (-1) and 14.0 g ~ (-1), respectively.
【作者单位】：太原理工大学煤科学与技术教育部和山西省重点实验室;
【基金】：国家自然科学基金(No.U1510203,No.21276169) 山西省青年科技研究基金(No.2015021030)资助项目
【分类号】：O621.251

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