钯(Ⅱ)催化CO/乙烯交替共聚反应机理——反应状态下钯/膦配位结构的原位^(31)P NMR研究

Mechanism of Palladium-Catalyzed Alternating Copolymerization of CO with Ethylene——In Situ 31P NMR Studies on Palladium-Phosphine Coordinate Structure under Reaction Conditions

应用加温加压原位核磁技术,考察了不同配比的钯/膦催化剂在共聚反应条件下(C_2H_4/CO=1:1,2.0MPa)的^(31)P NMR谱.实验表明,在C_2H_4/CO共聚反应条件下,DPPP(1,3-双二苯基膦丙烷)与Pd(OAc)_2生成比较稳定的六元环螯合物,没有发现游离DPPP的^(31)P NMR信号.当反应温度高于100℃时,螯合物即开始分解;反应温度高于260℃时,螯合物完全分解.DPPP/Pd(OAc)_2=1时,在反应条件下生成有活性的螯合物(DPPP)Pd(OCOCF_3)_2;DPPP/Pd(OAc)_2≥2时,在反应条件下生成无活性螯合物(DPPP)_2Pd(OCOCF_3)_2.

Palladium - phosphine catalyst with different DPPP/Pd(OAc)2 ratio has been studied with in situ 31P NMR spectroscopy under reaction conditions (C2H4/CO 1: 1, 2.0MPa) . The results showed that the reaction of DPPP with Pd(OAc)2 produced a stable six - membered ringcomplex which had efficient catalytic activity. When the reaction temperature was above 100℃,the complex began to decompose. When the reaction temperature was above 260 t, the complex decomposed completely. No free DPPP was found in the experiment. The active complex (DPPP) Pd(OCOCF3)2was formed when DPPP/Pd = 1.The unactive complex (DPPP)2Pd(OCOCF3)2was formed when DPPP/Pd≥2.