【作者】 李考学；

【导师】 金子林； 王艳华；

【作者基本信息】 大连理工大学 ， 精细化工， 2010， 博士

【摘要】 可溶性过渡金属纳米催化剂因其高活性、高选择性等特性正引起人们的广泛关注,但与经典均相催化过程相似,从工业应用考虑,仍存在如何有效地解决催化剂与产物的分离及循环使用的问题。本论文通过氢气还原法制备了以具有浊点(Cp)特性的温控膦配体Ph2P(CH2CH2O)nCH3(n=16)(L)为稳定剂的Rh纳米催化剂,并实现了其在水/1-丁醇两相体系中的温控相转移功能。即室温下,溶于水相的Rh纳米催化剂,在温度升高至浊点(60℃)以上时,Rh纳米催化剂从水相转移至上层1-丁醇相。当温度降至60℃以下时,Rh纳米催化剂又从1-丁醇相重返下层水相。基于该Rh纳米催化剂在水/1-丁醇两相体系中的温控相转移功能,本论文将其成功地用于高碳烯烃的加氢、氢甲酰化和氢氨甲基化反应,显示了催化剂易于分离并循环使用的特点。温控相转移Rh纳米催化剂在高碳烯烃加氢反应中显示了优异的催化活性及分离循环使用效果。对于环己烯加氢反应,在P/Rh=2(摩尔比),S/Rh=1000(摩尔比),T=60℃,PH2=1 MPa,t=1 h的优化反应条件下,环己烯转化率为100%,TOF达1000 h-1,催化剂循环使用6次,催化活性保持不变,催化剂平均流失量(质量百分比)为0.2%。对该催化剂在高碳烯烃氢甲酰化反应中的研究表明,在T=70℃,P/Rh=13(摩尔比),S/Rh=1000(摩尔比),P=5 MPa(CO/H2=1:1),反应时间6 h条件下,1-辛烯的转化率和醛收率分别达到98%和96%。反应结束后,催化剂和产物通过简单的相分离即可分开,催化剂连续使用3次,催化活性未见明显降低。首次将Rh纳米催化剂用于催化高碳烯烃氢氨甲基化反应,考察了催化剂的催化性能及分离回收效果。对于1-辛烯氢氨甲基化反应,在T=120℃,S/Rh=1000(摩尔比),P/Rh=2(摩尔比),P=6 MPa(CO/H2-1:1),t=4 h条件下,1-辛烯转化率和胺选择性分别达到99%和97%。催化剂连续使用3次,1-辛烯转化率保持不变,胺选择性保持在85%以上以上研究结果表明,Rh纳米催化剂的温控相转移功能,为可溶性过渡金属纳米催化剂的分离回收开辟了一条新途径。更多还原

【Abstract】 Soluble transition-metal nanoparticles in catalysis have drawn much attention due to their high efficiency and selectivity. However, very similar to traditional homogeneous catalysts, one of the main disadvantages of soluble nanoparticle catalysts is the problem of separation the catalyst from the products. In this paper, rhodium nanoparticles stabilized by thermoregulated ligand Ph2P(CH2CH2O)nCH3(n= 16)(L) were prepared by hydrogenation reduction. The rhodium nanoparticle catalyst stabilized by thermoregulated ligand L exhibited the thermoregulated phase-transfer property in the aqueous/1-butanol biphasic system, That is to say, the rhodium nanoparticle catalyst was in the lower water phase at room temperature, afterwards, when the temperature heated to 60℃, the rhodium nanoparticle catalyst transferred from the water phase into the upper 1-butanol phase, after cooling to room temperature, the rhodium nanoparticle catalyst could go back to the lower water phase from the upper 1-butanol phase.The thermoregulated phase-transfer property of rhodium nanoparticle catalyst stabilized by thermoregulated ligand L in the aqueous/1-butanol biphasic system and its catalytic effect on the hydrogenation, hydroformylation and hydroaminomethylation of higher olefins were investigated.The thermoregulated phase-transfer rhodium nanoparticle catalyst was used to catalyze hydrogenation of olefins. The catalytic activity and recycling efficiency of the catalyst were studied in detail. For the hydrogenation of cyclohexene catalyzed by the thermoregulated phase-transfer rhodium nanoparticle catalyst in the aqueous/1-butanol biphasic system, under the conditions of P/Rh= 2(molar ratio), S/Rh= 1000(molar ratio), T=60℃, PH2= 1 MPa and t= 1 h, the conversion of cyclohexene reached up to 100%and the TOF was 1000 h-1. Catalytic activity remained unchanged within six successive runs. The average leaching of rhodium to the product phase was 0.2 wt.%.We extended the application of the thermoregulated phase-transfer rhodium nanoparticle catalyst to the hydroformylation of higher olefins. Under the conditions of T= 70℃, P/Rh= 13(molar ratio), S/Rh=1000(molar ratio), P= 5 MPa(CO/H2= 1:1), t= 6 h, the conversion of 1-octene and yield of aldehyde were 98% and 96%, respectively. The catalyst could be easily separated from product by phase separation and used for three times without evident loss in activity.Rhodium nanoparticle catalyst was used to catalyze hydroaminomethylation of higher olefins for the first time. For the hydroaminomethylation of 1-octene, under the conditions of T = 120℃, S/Rh= 1000(molar ratio), P/Rh= 2(molar ratio), P= 6 MPa (CO/H2=1:1), t= 4 h, the conversion of 1-octene and the selectivity for amine were up to 99% and 97%, respectively. Moreover, the catalyst could be recycled at least three runs.In summary, the methodology of TRPTC of nanoparticle catalysis system is simple to realize and the catalyst is easy to separate from the product and recycle. Therefore, it opens up a new avenue for recovery and recycling of soluble transition-metal nanoparticle catalyst.更多还原