Karakanov Edward A, Zolotukhina Anna V, Ivanov Andrey O, Maximov Anton L
Department of Petroleum Chemistry and Organic Catalysis Moscow State University 119991 Moscow Russian Federation.
A.V. Topchiev Institute of Petrochemical synthesis RAS 119991 Moscow Russian Federation.
ChemistryOpen. 2019 Mar 28;8(3):358-381. doi: 10.1002/open.201800280. eCollection 2019 Mar.
Heterogeneous Pd-containing nanocatalysts, based on poly (propylene imine) dendrimers immobilized in silica pores and networks, obtained by co-hydrolysis in situ, have been synthesized and examined in the hydrogenation of various unsaturated compounds. The catalyst activity and selectivity were found to strongly depend on the carrier structure as well as on the substrate electron and geometric features. Thus, mesoporous catalyst, synthesized in presence of both polymeric template and tetraethoxysilane, revealed the maximum activity in the hydrogenation of various styrenes, including bulky and rigid stilbene and its isomers, reaching TOF values of about 230000 h. Other mesoporous catalyst, synthesized in the presence of polymeric template, but without addition of Si(OEt), provided the -cyclooctene formation with the selectivity of 90-95 %, appearing as similar to homogeneous dendrimer-based catalysts. Microporous catalyst, obtained only on the presence of Si(OEt), while dendrimer molecules acting as both anchored ligands and template, demonstrated the maximum activity in the hydrogenation of terminal linear alkynes and conjugated dienes, reaching TOF values up to 400000 h. Herein the total selectivity on alkene in the case of terminal alkynes and conjugated dienes reached 95-99 % even at hydrogen pressure of 30 atm. The catalysts synthesized can be easily isolated from reaction products and recycled without significant loss of activity.
通过原位共水解制备了基于固定在二氧化硅孔和网络中的聚（丙烯亚胺）树枝状大分子的多相含钯纳米催化剂，并对其在各种不饱和化合物氢化反应中的性能进行了研究。发现催化剂的活性和选择性强烈依赖于载体结构以及底物的电子和几何特征。因此，在聚合物模板和四乙氧基硅烷同时存在的情况下合成的介孔催化剂，在各种苯乙烯的氢化反应中表现出最高活性，包括体积庞大且刚性的芪及其异构体，其TOF值达到约230000 h⁻¹。在聚合物模板存在但未添加Si(OEt)₄的情况下合成的其他介孔催化剂，生成环辛烯的选择性为90 - 95%，表现得与基于均相树枝状大分子的催化剂相似。仅在Si(OEt)₄存在下获得的微孔催化剂，同时树枝状大分子分子既作为锚定配体又作为模板，在末端线性炔烃和共轭二烯的氢化反应中表现出最高活性，TOF值高达400000 h⁻¹。在此，即使在30 atm的氢气压力下，末端炔烃和共轭二烯的烯烃总选择性也达到95 - 99%。合成的催化剂可以很容易地从反应产物中分离出来并循环使用，而活性不会有明显损失。
