Construction Of Triacetonamine And Chiral Michael Adduct Over Modified Solid Acids

As well known, solid acids are a kind of green catalysts. Recently, the replacement of traditional catalysts with solid acids has been an important trend in chemical industry. Therefore, in this paper, we tried to develop a highly efficient and selective solid acid for the synthesis of triacetonamine from acetone and ammonia instead of acidic salts and acyl chlorides. In addition, the modification of solid acids with chiral organic molecules was investigated for the asymmetric Michael addition of aldehyde or ketone to β-nitrostyrene without any additional acids. The detailed information was summaried as follows.1. Several H-type zeolites were chosen and evaluated with the synthesis of triacetonamine from acetone and ammonia. In which, HY exhibited the best catalytic performance. Then, HY was modified with Na OH aqueous solution and the modified HY were characterized by XRD, BET, NH3-TPD and IR spectra of adsorbed pyridine.The results indicated that Br?nsted acid was more important than Lewis acid for the reaction of acetone and ammonia to yield triacetonamine.2. A series of acidic resins were chosen and examined for the synthesis of triacetonamine from acetone and ammonia. Sulfonic acid resin NKC-9 displayed the best catalytic performance. Under the optimized conditions, the conversion of acetone was 55.8% and the selectivity of triacetonamine was 57.5%. Besides, the recycling of the light fractions was realized over NKC-9. Therefore, a continuous, green and efficient process was established for the synthesis of triacetonamine.3. Sulfonic acid or sulfuric acid modified solid oxides were prepared by the different methods and employed for the synthesis of triacetonamine from acetone and ammonia.Sulfonic acid modified silica through the polycondensation and oxidation exhibited the excellent catalytic performance. Therefore, a series of catalysts bearing sulfonic acid groups were prepared and characterized by elemental analysis, XPS, TG and BET. The results showed that the increase of sulfonic acid group amounts would lead to the decrease of the BET surface area and mesoporous volume. When the amount of sulfonic acid groups was 0.98 mmol/g, the catalytic performance was optimal. The conversion of acetone and the selectivity of triacetonamine were 44.7% and 58.1%,respectively.4.(1R, 2R)-(+)-1, 2-Diphenyl ethylenediamine modified resins were prepared and evaluated with the asymmetric Michael addition of acetone to β-nitrostyrene. Themodified sulfonic acid resin exhibited the best catalytic performance. The results of characterizations presented that sulfamide, primary amine and sulfonic acid on the surface of this catalyst played a synergistic effect on this reaction. Under the optimal reaction conditions, 65.5% of β-nitrostyrene conversion and 93.0% of the Michael adduct enantioselectivity were obtained. Moreover, this catalyst was applied for the asymmetric Michael addition of aldehyde or ketone to β-nitroolefins. Except for isobutylaldehyde, the enantioselectivities of other adducts were all above 81% and the catalyst exhibited the good generality.