Synergistic Catalysis Between Lewis Acids And HTLc In Oxidation Reaction

Isophorone is a great solvent of polymer compound and an important intermediate of chemical industry, and its selective oxidation product ketoisophorone, is the key intermediate for the synthesis of various carotenoids and flavoring substances. But since the isophorone has been industrial produced, almost all the key technologies and most of volume of production have been kept from us. Along with the development of native fine chemical industry, the demand of native produced isophorone and cost reduction kept growing. It is meaningful for us to do research about the direct oxidation from isophorone to ketoisophorone.The reason that isophorone is hard to be directly oxidized, because there is conjugation effect between C=O and C=C which enhances the C-H bond of allylic position. If we find an easy way to weaken the electronic delocalization effect between C=O and C=C, the C-H bond dissociation energy will be decreased efficiently. C-H activation makes isophorone easy to be oxidized. What we want to present here is a method without catalyst modified to weaken the delocalization effect and activate the substrate.The main work of this thesis is based on the predecessors, we use coprecipitation to synthetize HTLcs with Cu, Mg and Al. We make Lewis acid as our additives here, it weakens the electronic delocalization effect of isophorone and makes the C-H bond of allylic position activated. Eventually we improve the efficiency of isophorone oxidation. Here are the main conclusions:(1) The synthetized catalyst is NO3-intercalated HTLc with hexagonal system and some amount of H2O. The ratio of the amount of substance of three metal elements in the catalyst is close to their raw ratio, Cu:Mg:A1≈1:3:1. We calculate the molality of each metal element with results of TGA and ICP.(2) By adding different kinds of Lewis acids as additives, the reaction time of isophorone oxidation is shortened from48h to4h without the decrease of the target product yield. Among all kinds of additives, ZnCl2, AICl3and SnCl2 are more efficient.(3) Through a series of researches, we get two optimized conditions. A has the maximum yield of the target product KIP and b has the maximum catalytic reaction efficiency. a.60℃,0.1g HTLc,20%molar weight of isophrone ZnCl2,350%molar weight of isophrone TBHP b.60℃,0.025g HTLc,20%molar weight of isophrone ZnCl2,250%molar weight of isophrone TBHP The reaction time is4h. Under condition a, yield of target product KIP is53.6%(100%selectivity), TOF=4.4/h, and under condition b, yield of KIP is43.0%(100%selectivity), TOF=141.0/h.(4) A computational simulation confirms that the lewis acid does make the substrate more active.1HNMR and ultra violet absorption spectroscopy gave evidence on the existence of interaction between the additive and isophorone.In brief, the presented way to improve the catalytic reaction efficiency is achievable and novel. It gives us a new thinking of studying catalytic reactions.