摘要
合成了多个基于钴氰化锌的双金属氰化络合物(DMC)催化剂,并对催化剂的结晶形态进行了表征.考察了制备过程中,有机配体及其引入方式,温度,搅拌速度对DMC催化剂形态的影响.其中有机配体对DMC催化剂形态的影响是最主要的.有机配体中富电子原子的电负性的强弱和数量共同影响着DMC催化剂的形态.该类原子的电负性越强,得到的DMC催化剂的结晶性越差,无定型部分的比例越高,并且单个原子的电负性强弱比该类原子的数量在此间的影响更大.而在有机配体预先存在的情况下,该沉淀体系则更有利于无定型部分的产生.在30℃左右的沉淀反应温度下,得到的DMC催化剂的无定型部分比例最高.在有机配体存在的情况下,搅拌速度对DMC催化剂形态的影响有限.并且发现存在于有机配体中的DMC催化剂随着时间的推移,形态会发生变化.初步揭示了DMC催化剂的形态与其催化活性间的关系.而无定型态的DMC催化剂更有利于PO的聚合.
A number of double metal cyanide (DMC) complexes based on Zn_3[Co(CN)_6]_2 were prepared, and their morphologies were characterized by XRD. Effects of different organic ligands and their complexing ways, temperature and shear stirring rate in DMC complexes preparation on their morphologies were studied in this paper. Among those factors, organic ligand was the most important matter influencing the morphology of DMC complex. The results showed that the electronegativity of atom with affluent electrons and the number of such atoms in organic ligands together influence the morphologies of DMC complexes. The stronger the electronegativity of such atom is, the lower is the crystallinity of DMC complex prepared. It was proved that the strength of the electronegativity of such single atom is more effective than the number of such atoms on the morphology of DMC complex. Amorphous DMC complex was favorably formed in this reaction system if the organic ligand exists before precipitation. The proper precipitation reaction temperature is about 30℃ so that the crystallinity of DMC complex prepared is the lowest. The effect of shear stirring rate on the morphology of DMC complex in its preparation was limited when existing organic ligand exists before precipitation. Another important factor in our research is that the morphology of DMC complex in organic ligand is not stable, it changes with time. At last, the relationship between the morphology of DMC complex and its catalytic activity was presented. It was found that amorphous DMC catalyst is more active to PO polymerization.
出处
《浙江大学学报（理学版）》
CAS
CSCD
2004年第1期74-78,共5页
Journal of Zhejiang University（Science Edition）
