Study Of Novel Methods On Oxidation Of Isophorone And Chlorination Of Butanone

Oxidation reaction has been an interesting area of research in organic syntheses for preparing pharmaceutical materials and flavorings. Environmental and economic pressures are forcing industry urgently to develop new clean catalytic technologies to produce these fine chemicals to overcome these stoichiometric oxidations. We used molecular oxygen and hydrogen peroxide as an oxidant because they are the most desired oxygen source. These reactions such as catalytic oxidation of α-isophorone (α-IP) to keto-isophorone (KIP) with molecular oxygen, oxidation of a-IP to 3, 3- dimethyl-5-oxo-hexanoic acid with hydrogen peroxide, and oxidation-chlorination of butanone to 3-chloro-2-butanone with H₂O₂-HC1 have been investigated in this thesis. Acquired research results as follows:1) The copper chloride-catalyzed oxidation of a-IP with dioxygen in acetylacetone gave KIP in 57% yield, with respect to the remarkably short reaction time (10 h versus 5 day) and even in the lower reaction temperature (100 °C versus 150 °C). The new catalytic system broke through the limit of traditional way in heterogeneous molybdenum based systems. The experimental apparatus was devised for oxidation of a-IP to KIP. An advantage of the concept is that it avoids deactivation of catalyst with water formed during oxidation process. Reaction conditions were optimized. A possible mechanism of aerobic oxidation a-IP catalyzed by CuCl₂ was proposed based on an investigation by density functional theory (DFT).2) a-IP was oxidized to 3, 3-dimethyl-5-oxo-hexanoic acid with hydrogen peroxide in the present of catalyst V₂O₅ with the aim ofovercoming these stoichiometric oxidations. The influences of reaction conditions such as solvent, reaction temperature, reaction time, ratio of reactants, catalyst were examined in detail. The results showed that the increase of amount of catalyst and prolongation of reaction time could enhance the conversion of a-IP and the selectivity of 3, 3-dimethyl-5-oxo-hexanoic acid. Furthermore, the selectivity of 3, 3-dimethyl-5-oxo-hexanoic acid and 5-acetyl-4, 4-dimethyl-dihydro-furan-2(3H)-one were accessible to pH of the system. A mechanism of oxidation was proposed for the above phenomenon.3) 3-chloro-2-butanone was eco-friendly synthesized by chlorination in situ with HC1-H2O2. The optimum preparation conditions were CuCl2 as catalyst, n(butanone):n(HCl):n(H2O2)=2:l:1.3, reaction temperature 78 °C and reaction time 5 h. The conversion of butanone amounted to 52.43%, and the selectivity of 3-chloro-2-butanone was over 76%. The selectivity of product was interpreted by using density functional theory (DFT) from the molecular figuration.