摘要
采用分步浸渍法制备了硼改性Cu/Al2O3催化剂,利用XRD、FTIR、UV-Vis、N2吸附、H2-TPR、NH3-TPD和N2O解离吸附等方法对其结构进行了表征,研究了硼改性对催化剂结构及其催化甘油氢解反应性能的影响。结果表明,先浸渍硼再浸渍Cu时,随硼含量提高,催化剂酸量和Cu分散度增加,Cu与硼物种的相互作用增强。先浸渍Cu后浸渍硼时,催化剂的酸量提高、Cu物种分散程度变化不明显。先浸渍硼明显提高了Cu/Al2O3活性及1,2-丙二醇选择性。在220℃、3 MPa、质量空速2.0 h-1及H2/甘油比为20的条件下,随硼含量提高,甘油转化率及1,2-丙二醇选择性呈现增大趋势,其中硼含量为2%的催化剂上甘油转化率及1,2-丙二醇选择性分别达到99.9%和96.2%。硼改性对Cu/Al2O3催化性能的促进作用与催化剂酸性提高及Cu与B之间的相互作用有关。
Boron modified Cu / Al2O3 catalysts were prepared by the stepwise impregnation method. The catalyst property was characterized by XRD,FTIR,UV-Vis,N2-sorption,H2-TPR,NH3-TPD and dissociative N2 O adsorption. The effects of the impregnation sequence and the boron content on the catalyst structure and performance were investigated. It was found that the addition of boron to Cu / Al2O3 can not only increase catalyst acidity but also enhance the Cu dispersion. It is obvious as the boron species was first introduced to the catalyst. Meanwhile,a strong interaction was formed between the boron and Cu species. However,the strong interaction reduced the number of the surface Cu atoms due to the coverage with the B species. This was more serious when the boron species was impregnated after Cu. In the hydrogenolysis of glycerol to 1,2-propanediol,the addition of boron before Cu more favored the performance of Cu / Al2O3. Under the condition of 220 ℃,3. 0 MPa,weight hourly space velocity of 2. 0 h- 1,and the H2/ glycerol ratio of 20,with increasing the boron mass content from 0 to 2%,the glycerol conversion and the selectivity to 1,2-PDO increased from 17. 1% to 99. 9% and from 83. 7% to 96. 2%,respectively. The promotion effect of boron was found to correlate with the increased acidity and the interaction between Cu and B species.
出处
《化学工业与工程》
CAS
CSCD
2015年第6期13-17,共5页
Chemical Industry and Engineering
关键词
甘油氢解
铜催化剂
硼
1
2-丙二醇
酸性
分散度
glycerol hydrogenolysis
copper catalyst
boron
1,2-propanediol
acidity
dispersion
