It is known that the first lanthanide （Ln） catalyst used for stereospecific polymeriza-tion of conjugated diene is composed of LnCl3 and R3Al.It initiates stereospecific polymeri-zation of butadiene with a very high...It is known that the first lanthanide （Ln） catalyst used for stereospecific polymeriza-tion of conjugated diene is composed of LnCl3 and R3Al.It initiates stereospecific polymeri-zation of butadiene with a very high cis-1, 4 content（98%）, yet owns poor activity. This paper presents the new results obtained in our laboratory. By adding alcohol tothis binary system （LnCl3-R3Al）, the catalytic activity is greatly enhanced without any losson its high stereospecificity. It is shown that the catalytic activity is dependent on the ratioof its components and their order of addition. Furthermore, we have ascertained that itis the alcohol complex of LnCl3 with a definite composition LnCl3.R3OH, that turns out tobe an active catalyst when treated with R3Al.展开更多
China is rich in rare earth resources. Rare earth elements, also named lanthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coor...China is rich in rare earth resources. Rare earth elements, also named lanthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis-1,4-polybutatine rubber and cis-1,4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.展开更多
文摘It is known that the first lanthanide （Ln） catalyst used for stereospecific polymeriza-tion of conjugated diene is composed of LnCl3 and R3Al.It initiates stereospecific polymeri-zation of butadiene with a very high cis-1, 4 content（98%）, yet owns poor activity. This paper presents the new results obtained in our laboratory. By adding alcohol tothis binary system （LnCl3-R3Al）, the catalytic activity is greatly enhanced without any losson its high stereospecificity. It is shown that the catalytic activity is dependent on the ratioof its components and their order of addition. Furthermore, we have ascertained that itis the alcohol complex of LnCl3 with a definite composition LnCl3.R3OH, that turns out tobe an active catalyst when treated with R3Al.
文摘China is rich in rare earth resources. Rare earth elements, also named lanthanides, are number 58 to number 81 elements in the elemental periodic table. They have unique electronic structures and may form various coordination compounds. In the early 1960s, researchers at the Changchun Institute of Applied Chemistry, Chinese Academy of Sciences (CIAC) found the catalytic activities of lanthanide compounds in stereospecific polymerization of conjugated dienes, and published the first paper on this topic in 1964. On the basis of this finding, CIAC launched extensive research activities on lanthanide compounds as diene polymerization catalysts, from a series of fundamental research to the efforts of industrializing the rare earth catalyzed cis-1,4-polybutatine rubber and cis-1,4-polyisoprene rubber. This review aims to summarize the progress in this field in the past half century.
