Abstract:

Metal catalysis plays a crucial role in the Heck reaction, but it is prone to issues such as metal residue. In response to this issue, this article has developed a new way of encapsulating metal catalysts, which involves uniformly mixing the metal catalyst with organic silicone adhesive or uniformly mixing the metal catalyst with Fe₃O₄ and organic silicone adhesive. The resulting supported catalysts or magnetic supported catalysts are less prone to fragmentation, maintain good catalytic activity, and are easier to weigh and transfer, while also being readily filterable and recoverable. Experiments show that after 7 cycles of use, the organic silicone gel supported palladium catalyst （Pd/C@Glue） can still achieve a product yield of 85% in the Heck reaction, indicating that Pd/C@Glue has a high catalytic cycling efficiency in the Heck reaction. In addition, Pd/C@Glue is cycled 7 times in the Heck reaction, and the residual palladium content in the reaction solution is all below 26 ppm, indicating a low amount of metal leaching in the reaction solution. In order to achieve magnetic recovery of catalysts, a novel magnetic supported catalyst is obtained by simultaneously loading Fe₃O₄ and palladium catalysts onto organic silicone gel （Pd/C-Fe₃O₄@Glue） in this paper. Experiments show that the magnetic catalyst has good catalytic effect after multiple cycles of use.

Key words: organosilicone gel, catalyst support, catalysis, Heck reaction, metal residue, recovery