蒸气浸渍法制备完全无氯CuY催化剂及其氧化羰基化性能

Preparation of chlorine-free CuY catalysts by vapour impregnation and their application for oxidative carbonylation

以具有升华性质且易分解的乙酰丙酮铜为铜源,NH4Y分子筛为载体,采用蒸气浸渍法制备了CuY催化剂,考察了其对甲醇氧化羰基化合成碳酸二甲酯的催化性能,并采用XRD、H2-TPR和NH3-TPD等表征手段研究了催化剂上铜物种的分散状态、催化活性中心的含量及催化剂的酸强度和浓度,发现铜物种在Y分子筛载体上高度分散,且Y分子筛载体的晶体结构保持完好。在N2∶H2=12∶1的气氛中,250℃还原得到的催化剂CuY/250催化活性中心含量最高,催化活性也达到了最佳,其甲醇转化率为11.1%,碳酸二甲酯的时空收率和选择性分别为200.5mg/(g·h)和60.3%。

CuY catalysts were prepared by vapour impregnation with copper acetylacetonate as the copper source and NH4Y zeolite as the support.The performance of the catalysts was evaluated by using direct vapor-phase oxidative carbonylation of methanol to dimethyl carbonate(DMC)as a model reaction.The surface dispersion,active component content,acid strength and concentration of the as-prepared catalysts were characterized by X-ray diffraction(XRD),H2-temperature programmed reduction(H2-TPR)and NH3-temperature programmed desorption(NH3-TPD),respectively.It was found that copper species were highly dispersed on the Y zeolite and the crystal structure of the Y zeolite remained intact.For the CuY/250 catalyst activated at 250℃and in the atmosphere of N2∶H2=12∶1,the active component content was the highest and the catalytic activity was excellent.The obtained methanol conversion,space time yield and selectivity of dimethyl carbonate were 11.1%,200.5mg/(g·h)and 60.3%respectively.