PDMS Sponge Loading Visible Light Catalyst And Its Application In CDC Reaction

Photocatalytic reaction is a kind of green cleaning reaction,usually with visible light as an energy source to induce the chemical reaction.Visible light induced REDOX reaction strategy has been widely applied in the synthesis of organic small molecules.By photochemical reaction,chemists have realized the substitution reaction of aldehyde ketone carbonyl alpha bits,cycloaddition,alpha amino carbon free radical reaction,aromatics and olefins trifluoro methylation,imine cations as intermediate reaction and so on,successfully constructed C-C key,C-O,C-P keys,C-N key.This paper introduces the visible light catalytic research progress in cross dehydrogenation coupling reaction,and the relevant study around the visible light catalytic: first,we choose a good pervious to light and stability polydimethylsiloxane(PDMS)as organic sponge.Surface modification technology(air plasma)was used to the introduction of the hydroxyl groups on the sponge surface,then combined with 2-propylene acyl methyl ethyl trimethyl ammonium chloride(METAC).Finally,by radical polymerization and ion exchange technology,loading organic dye(Rose Bengal,RB)on PDMS-MATAC sponge,to get the organic photocatalyst PDMS-RB.Through SEM and EDS methods to qualitative analysis PDMS-RB sponge photocatalyst materials,and quantitative characterization by 1H NMR to confirm the RB on the PDMS-RB sponge photocatalyst is 0.01mmol/g.Applications,at the presence of the PDMS-RB sponge photocatalyst for tetrahydroisoquinoline derivatives with nitromethane,acetone,ethyl acetate class diazo reaction has universal applicability,expected to the catalytic effect is obtained.Compared with traditional silica,polymer,metal organic framework and graphene heterogeneous solid catalyst carrier need by filtering,the centrifugal method to realize the catalyst recycling,PDMS sponge carrier catalyst only by simple and easy operation,when reaction was finished the sponge grab directly to the reaction system can achieve the catalyst recycling.In addition to the recycling of the catalyst was studied,with N-phenyl tetrahydroquinoline and nitromethane as model reaction,catalyst recycle number 15 times or more(85% yield),and the catalytic activity was not significantly reduced.For further validation of PDMS-RB light catalyst in industry should be the feasibility of sponge,through a continuous flow reaction device(including a peristaltic pump,a glass tube and a lamp).In the test to N-phenyl tetrahydroquinoline with nitromethane put a lot of response for the model,only 48 hours have achieved 88% efficiency of column chromatography,at this time the dosage of the catalyst was only 1.4 mol %.This is a simple device,easy to build a simple organic chemistry laboratory can set up the device to do large-scale synthesis reaction.In addition,we found a new reaction type of RB visible catalyst,the N phenyl tetrahydroisoquinoline and maleic anhydride derivatives [3+ 2] cycloaddition reaction.The RB combined with transition metal salt is first applied in the tertiary amine α C-H bond ene reaction.PDMS sponge through covalent modification,glutamate,RB and proline were succeeful connected on PDMS sponge,hydrophobic bifunctional catalyst was prepared.With tetrahydroisoquinoline and aryl acetone manny ene reaction as a template,this catalyst was verified under the condition of water as the solvent.Conclusion: through the surface modification technology of polymer materials was modified PDMS sponges,sponge after modification by ion exchange technology combined with visible light catalyst rosy,successfully developed a simple and efficient organic sponge photocatalyst.Under visible light irradiation,the CDC coupling reaction,sponge light catalyst shows excellent catalytic activity.PDMS organic sponge photocatalyst has: strong stability,easy to recycle and reuse,high reactivity,easy to a large scale of experiments.The results show that the PDMS sponge is a promising heterogeneous catalytic carrier.For other catalyst loading on PDMS sponge(including multifunctional catalyst and the stereo-selectivity of CDC reaction)and the related more interesting conversion are under way.