Research On Hydrosilylation Reaction For The Synthesis Of Silane Coupling Agent KH-560

The catalytic hydrosilylation of unsaturated compounds is one of the most elegant methods for the synthesis of organosilicon compounds.Platinum catalysts displayed very high activity in the hydrosilylation reaction.The Speier catalyst(H₂PtCl₆ dissolved in i-propanol), and the Karstedt catalyst(H₂PtCl₆ dissolved in tetramethyldivinyldisioxane[(CH₂=CHSi Me₂)₂O]),have found widespread use in the silicon industry.Unfortunately,the drawbacks of these catalysts were their very limited stability,rapid formation of platinum colloids, significant amounts(20%～40%) of the isomeric alkenes.All the drawbacks often resulted in undesired side reactions.To overcome some of these undesired side reactions,there has been a marked interest in the development of newer and different catalysts for the hydrosilylation reaction.In this paper,Pt-complexes as catalysts for the hydrosilylation of allyl glycidyl ether (AGE) with trimethoxysilane(TMOS) to prepareγ-glycidoxypropyltrimethoxysilane(KH-560), is studied.The Pt complexes with different ligands(such as Pt-N(C₂H₅)₃,Pt-N (CH₂CH₂CH₃)₃,Pt-P(Ph)₃ and Pt-Piperidine) for the catalyzing hydrosilylation were compared.The results showed that the Pt-N(C₂H₅)₃ for the hydrosilylation reaction had higher activity.The Pt-N(C₂H₅)₃ complexes catalyzing the synthesis of KH-560 were investigated in details.The structures of the products were analyzed by GC-MS;The mechanism of the hydrosilylation reaction was in a preliminary discussion.Under the optimal conditions:n (AGE):n(TMOS):n(Pt-triethylamine)=(1:1.05～1:1.10):6.72×10^-6,55℃～75℃,20min～60min,the yield of KH-560 mount to above 86%;And the formation of colloidal Pt species was not found during the course of the hydrosolylation reaction.1,4-Cyclohexanedimethanol(CHDM) was produced commercially by the hydrogenation of dimethyl terephthalate(DMT) in a two-stage catalytic process.Dimethyl 1,4-cyclohexane dicarboxylate(DMCD) is product of the first stage.In this paper,we found Ru/C was a good catalyst for hydrogenation of DMT to DMCD under low pressure.Under the optimized conditions of 110℃,3.0MPa,catalyst dosage 0.5g,DMT dosage 5g,THF dosage 30mL, conversion of DMT is as high as 99.6%and selectivity of DMCD is about 96.5%.Meanwhile, the Ru/C catalyst is reused for 17 runs.During lifetime test,reaction time is gradually prolonged to 8.5h and reaction temperature is step-wisely increased to 140℃to keep about 99.0%conversion of DMT and 95.0%selectivity of DMCD.