高等学校化学学报
高等學校化學學報
고등학교화학학보
CHEMICAL JOURNAL OF CHINESE UNIVERSITIES
2014年
7期
1559-1564
,共6页
张丹枫%李森%于文%孟兼冈
張丹楓%李森%于文%孟兼岡
장단풍%리삼%우문%맹겸강
后过渡金属催化剂%α-二亚胺镍配合物%甲基丙烯酸甲酯%聚合
後過渡金屬催化劑%α-二亞胺鎳配閤物%甲基丙烯痠甲酯%聚閤
후과도금속최화제%α-이아알얼배합물%갑기병희산갑지%취합
Late transition metal catalyst%α-Diimine nickel complex%Methyl methacrylate%Polymerization
以4种不同结构的α-二亚胺镍(Ⅱ)催化剂[( t-Bu)-N CH-CH N-( t-Bu)] NiBr2( C1),[C6 H5-N C ( Me)-C ( Me) N-C6 H5] NiBr2( C2),[(2,6-C6 H3( Me )2)-N (Me) N-(2,6-C6 H3(Me)2)]NiBr2(C3)和[(2,6-C6 H3(i-Pr)2)-N C(An)-C( An) N-(2,6-C6 H3(i-Pr)2)]NiBr2(An=acenaphthyl)(C4),在甲基铝氧烷(MAO)作用下,对甲基丙烯酸甲酯(MMA)进行催化聚合.以 C2为模型催化剂系统研究了 Al/ Ni 摩尔比、单体浓度、聚合温度、聚合时间和反应溶剂对催化活性及聚合物分子量的影响.在较适合的聚合条件(催化剂用量为1.6μmol, Al/ Ni 摩尔比为800, MMA 浓度为2.9 mol/ L,甲苯为溶剂,聚合温度为60℃,聚合时间为4 h)下,讨论了催化剂结构对催化活性和聚合物分子量的影响.研究发现,催化剂 C1~ C3催化 MMA 聚合均得到富含间规结构的聚甲基丙烯酸甲酯(PMMA).催化剂结构中空间位阻增大导致催化活性降低,空间位阻最小的 C1催化活性最高[达107.8 kg/(mol Ni· h)]；而空间位阻最大的 C4催化活性仅为7.8 kg/(mol Ni·h).催化剂结构中给电子效应增加有利于催化活性及聚合物分子量的增加. C2催化活性为62.5 kg/(mol Ni·h),所得聚合物的分子量为5.0×104；而具有较强给电子效应的 C3催化活性达到96.9 kg/(mol Ni·h),并得到更高分子量的聚合物(7.6×104).
以4種不同結構的α-二亞胺鎳(Ⅱ)催化劑[( t-Bu)-N CH-CH N-( t-Bu)] NiBr2( C1),[C6 H5-N C ( Me)-C ( Me) N-C6 H5] NiBr2( C2),[(2,6-C6 H3( Me )2)-N (Me) N-(2,6-C6 H3(Me)2)]NiBr2(C3)和[(2,6-C6 H3(i-Pr)2)-N C(An)-C( An) N-(2,6-C6 H3(i-Pr)2)]NiBr2(An=acenaphthyl)(C4),在甲基鋁氧烷(MAO)作用下,對甲基丙烯痠甲酯(MMA)進行催化聚閤.以 C2為模型催化劑繫統研究瞭 Al/ Ni 摩爾比、單體濃度、聚閤溫度、聚閤時間和反應溶劑對催化活性及聚閤物分子量的影響.在較適閤的聚閤條件(催化劑用量為1.6μmol, Al/ Ni 摩爾比為800, MMA 濃度為2.9 mol/ L,甲苯為溶劑,聚閤溫度為60℃,聚閤時間為4 h)下,討論瞭催化劑結構對催化活性和聚閤物分子量的影響.研究髮現,催化劑 C1~ C3催化 MMA 聚閤均得到富含間規結構的聚甲基丙烯痠甲酯(PMMA).催化劑結構中空間位阻增大導緻催化活性降低,空間位阻最小的 C1催化活性最高[達107.8 kg/(mol Ni· h)]；而空間位阻最大的 C4催化活性僅為7.8 kg/(mol Ni·h).催化劑結構中給電子效應增加有利于催化活性及聚閤物分子量的增加. C2催化活性為62.5 kg/(mol Ni·h),所得聚閤物的分子量為5.0×104；而具有較彊給電子效應的 C3催化活性達到96.9 kg/(mol Ni·h),併得到更高分子量的聚閤物(7.6×104).
이4충불동결구적α-이아알얼(Ⅱ)최화제[( t-Bu)-N CH-CH N-( t-Bu)] NiBr2( C1),[C6 H5-N C ( Me)-C ( Me) N-C6 H5] NiBr2( C2),[(2,6-C6 H3( Me )2)-N (Me) N-(2,6-C6 H3(Me)2)]NiBr2(C3)화[(2,6-C6 H3(i-Pr)2)-N C(An)-C( An) N-(2,6-C6 H3(i-Pr)2)]NiBr2(An=acenaphthyl)(C4),재갑기려양완(MAO)작용하,대갑기병희산갑지(MMA)진행최화취합.이 C2위모형최화제계통연구료 Al/ Ni 마이비、단체농도、취합온도、취합시간화반응용제대최화활성급취합물분자량적영향.재교괄합적취합조건(최화제용량위1.6μmol, Al/ Ni 마이비위800, MMA 농도위2.9 mol/ L,갑분위용제,취합온도위60℃,취합시간위4 h)하,토론료최화제결구대최화활성화취합물분자량적영향.연구발현,최화제 C1~ C3최화 MMA 취합균득도부함간규결구적취갑기병희산갑지(PMMA).최화제결구중공간위조증대도치최화활성강저,공간위조최소적 C1최화활성최고[체107.8 kg/(mol Ni· h)]；이공간위조최대적 C4최화활성부위7.8 kg/(mol Ni·h).최화제결구중급전자효응증가유리우최화활성급취합물분자량적증가. C2최화활성위62.5 kg/(mol Ni·h),소득취합물적분자량위5.0×104；이구유교강급전자효응적 C3최화활성체도96.9 kg/(mol Ni·h),병득도경고분자량적취합물(7.6×104).
Four α-diimine nickel( Ⅱ) complexes: [( t-Bu)-N CH-CH N-( t-Bu)] NiBr2 ( C1), [C6 H5-N C ( Me-C ( Me) N-C6 H5 ] NiBr2 ( C2), [(2,6-C6 H3 ( Me) 2 )-N C ( Me)-C · (Me) N-(2,6-C6 H3(Me) 2 )]NiBr2(C3) and [(2,6-C6 H3 ( i-Pr) 2 )-N C ( An)-C ( An) N-(2,6-C6 H3(i-Pr) 2 )]NiBr2 (An =acenaphthyl)(C4), in the presence of methylaluminoxane(MAO) as cocat-alyst, were applied in the polymerization of methyl mathacrylate(MMA). The influence of polymerization pa-rameters, such as molar ratio of Al/ Ni, monomer concentration, polymerization temperature and time, as well solvents were studied with complex C2 / MAO system. Based on these results, all nickel complexes were com-pared under optimized polymerization conditions{1. 6 μmol catalyst, n( Al) / n( Ni) = 800, [ MMA] = 2. 9 mol/ L, toluene as solvent, 60 ℃ for 4 h}. In each case, syndiotactic enriched polymer was obtained. The complexes with more bulky frame work exhibit lower catalytic activities, for example, C1 with the smallest bulky frame work gives the highest activity, 107. 8 kg / (mol Ni·h) while C4 with the biggest bulky frame work gives the lowest activity, 7. 8 kg / (mol Ni·h); The complexes with more electronic donor substituents exhibit higher activities and molecular weight of PMMA. The activity of C2 is 62. 5 kg / (mol Ni·h), and the molecular weight of PMMA is 5. 0×104 , while that of C3 is 96. 9 kg / (mol Ni·h) and produce higher molecu-lar weight of PMMA(7. 6×104 ).
