The Application Of Ag NPs/CTF-1 On The Carboxylation Of Terminal Alkynes

Great CO₂ emission amount is the main reason of global warming,therefore it has attracted people to pay a great effort to transform CO₂ into value-added product.Transforming terminal alkynes into carboxylic acid and carboxylic ester has been regarded as having a great application potential.In this paper,we construct a kind of porous organic frameworks called CTF(Covalent Triazine Framework),and add certain amount of Ag NPs onto the surface of CTF in order to synthesize Ag-x/CTF-1 and apply the synthetic system into the carboxylation of terminal alkynes.The support material,CTF-1,is synthesized by the polycondensation reaction of melamine and terephthalaldehyde and certain amount of Ag NPs is supported by the method of photoreduction or hydrothermal process.The morphology as well as the pore structure of synthesized catalyst are tested through the methods of SEM,TEM,XRD,BET,FTIR,SSNMR,CO₂-TPD and the stuff.It is discovered that at the actual Ag loading of 2.6%,the catalytic system reach a high yield with a low economic cost.The catalytic system,which is applied into the carboxylation reaction successfully at a low CO₂ pressure of 0.1 MPa,achieve the yield of 94%.The best catalytic condition is certified as 120 mg Ag NPs-2.6%/CTF-1,1 mmol substrate,1.5 mmol Cs₂CO₃,CO₂(0.1 Mpa)and DMF(5 m L),50 ^oC.This catalytic system can also be applied to different carboxylation reaction of terminal alkyens with different functional groups.The catalytic system has also been tested in the synthesis of carboxylic ester,and the best reaction condition is determined as 120 mg Ag NPs-2.6%/CTF-1,1 mmol substrate,1.5 mmol cinnamyl chloride,2 mmol Cs₂CO₃,CO₂(0.5 Mpa)and DMF(5 m L),60 ^oC,24 h and reach a yield of 93%.The cataytic system is reused for 6 times and no catalytic activity loss is found,indicating the good recycle property of this catalytic system.