摘要
考察了不同制备条件对 Pd- HSi W- Cr- Te/Si O2 催化剂性能的影响 ,并借助 XPS、XRD、BET、TEM等方法对催化剂进行了表征。结果表明 ,Si O2 经 60 0°C焙烧比 80 0°C焙烧效果更佳 ;合适的氯钯酸钠浸渍时间为 30 h;催化剂需经 C2 H4 、O2 和 N2 的混合气体在一定条件下活化。通过对这些制备条件的选择 ,催化剂的性能得到改善 ,此时乙烯的转化率达 4.0 % ,醋酸选择性 86.1 % ,醋酸时空收率为 1 85.0 g/( L· h)
In the research of direct oxidation of ethylene to acetic acid, the effect of manufacture conditions on the performance of Pd HSiW Cr Te/SiO 2 has been studied, and the catalyst was investigated by XRD, XPS, TEM techniques. It was found that SiO 2 calcining temperature, Na 2PdCl 4 maceration time and catalyst activating procedure were the prominent factors affecting the performance of the catalyst. The results were as follows: SiO 2 calcined at 600°C compared with 800°C, the former was preferred, which could provide suitable pore diameter and pore distribution. If Na 2PbCl 4 maceration time was not enough, the catalyst activity was bad, however, too long time was unfavorable for the selectivity of acetic acid. The appropriate maceration time was 30 hours. The catalyst must be activated with mixture gas of C 2H 4,O 2 and N 2. The composition of the activating gas was C 2H 4∶O 2∶N 2=71∶9∶20(mol ratio), and the activating temperature was 220°C. It must be noted that during the activating procedure the speed of temperature increase should be moderate. Too quick temperature increase would lead the active component to be agglutinated seriously. By choosing these conditions, the performance of the catalyst was improved. When the reaction conditions were as follows: T =190°C, p =0.80MPa, SV =4 000h -1 ,and the composition of reaction mixture gas was C 2H 4∶O 2∶N 2∶H 2O=50∶6∶14∶30(mol ratio), the conversion of C 2H 4 and the selectivity of acetic acid could reach 4.0% and 86.1% respectively, and the by products CO 2 and CH 3CHO decreased to 11.7% and 1.0%. The once through space time yield of acetic acid could reach 185.0g/ (L·h).
出处
《华东理工大学学报（自然科学版）》
CAS
CSCD
北大核心
2001年第3期230-233,237,共5页
Journal of East China University of Science and Technology
