四氢呋喃催化氨化合成吡咯烷

以H-ZSM-5系列分子筛、HY、Hβ、Al2O3等固体酸作为催化剂,在固定床反应器中考察了其对四氢呋喃催化氨化合成吡咯烷反应的催化性能。结果表明,n(Si)/n(Al)=80的H-ZSM-5催化剂的活性最佳,其催化四氢呋喃氨化合成吡咯烷的最佳工艺条件为:常压,反应温度350℃,氨气与四氢呋喃摩尔比6,停留时间6.9s,此时四氢呋喃的转化率为82.9%,吡咯烷的收率为62.3%。在优化条件下催化剂连续工作600h,四氢呋喃的转化率保持在75%以上,吡咯烷的选择性有所降低,但吡咯烷的收率仍然保持在55%以上。利用XRD、N2吸附-脱附和NH3-TPD等手段对使用前后的催化剂进行表征,得出催化剂活性下降是由于较长时间的连续反应使得催化剂表面产生了积炭,堵塞了催化剂内部较小孔径的孔道,覆盖了催化剂表面的酸性位点。利用空气氧化法对催化剂进行在线再生后,催化剂的催化性能基本恢复到初始水平。     

Iridium‐Catalyzed Allylic Amination Route to α‐Aminoboronates: Illustration of the Decisive Role of Boron Substituents

The development of a new route to α‐aminoboronates using an iridium‐catalyzed allylic amination on boronated substrates is described. Unlike the boronate group, the trifluoroborato substituent was found to govern the regioselectivity exclusively in favor of branched products. The transformation of an allylic substitution product into an α‐aminoboronic ester in an efficient way validated the implementation of this approach.     

Intramolecular Carbonyl Nitroso Ene Reaction Catalyzed by Iron(III) Chloride/Hydrogen Peroxide as an Efficient Tool for Direct Allylic Amination

A mild, simple oxidation protocol employing iron(III) chloride as a catalyst and hydrogen peroxide as a stoichiometric oxidant was found to be compatible with an intramolecular carbonyl nitroso ene reaction and allowed us to efficiently convert hydroxamic acids into a diverse range of 1,2‐ and 1,3‐amino alcohol derivatives in a single operation.     

Thermodynamics and kinetics of adsorption for heavy metal ions from aqueous solutions onto surface amino-bacterial cellulose

Amino-bacterial cellulose (amino-BC) was prepared by chemical modification of bacterial cellulose(BC). The adsorption characteristics and mechanism of amino-BC were studied. The results show that adsorption data can be fitted well by Langmuir equation and the pseudo-second order kinetics, indicating that the adsorption of amino-BC would obey monolayer molecule adsorption and the main action was chemisorption. Meanwhile, the adsorption process was studied by the Elovich equation and the intra-particle diffusion model, indicating that the absorption characteristics of metal ions on amino-BC is controlled by both film diffusion and particle diffusion. The increase of reaction temperature will accelerate the adsorbing rate because of endothermic reaction.     

1,1-二氨基-2,2-二硝基乙烯的合成研究

以2—甲基咪唑为原料，通过低温硝化，硝化产物胺化开环，两步合成了1，1—二氨基—2，2—二硝基乙烯(DADE)。对文献中报道的反应路线进行了适当的放大并对反应条件进行了优化。放大后产物最佳得率14．9％，比文献值(13.1％)略高。经IR，MS，NMR和元素分析鉴定了产物结构。     

Examination of the Aromatic Amination Catalyzed by Palladium on Charcoal

The Buchwald–Hartwig amination of aryl halides with secondary amines and functionalized aromatic amines catalyzed by solid‐supported palladium is reported. The choices of ligand, base and solvent are crucial for the successful coupling. The amination of aromatic iodides, bromides and chlorides can be easily achieved with palladium on charcoal in the presence of a biphenylphosphane‐type ligand at 80–110 °C. In addition, the palladium on charcoal catalyst is easily separable after the reaction, and reusable several times with only small activity loss.     

Stereoselectivity of Four (R)‐Selective Transaminases for the Asymmetric Amination of Ketones

Four (R)‐ω‐transaminases originating from Hyphomonas neptunium (HN‐ωTA), Aspergillus terreus (AT‐ωTA) and Arthrobacter sp. (ArR‐ωTA), as well as an evolved transaminase (ArRmut11‐ωTA) were successfully employed for the amination of prochiral ketones leading to optically pure (R)‐amines. The first three transaminases displayed perfect stereoselectivity for the amination of all substrates tested (ee >99%). Furthermore, the transaminase AT‐ωTA led in most cases to better conversion than ArR‐ωTA and HN‐ωTA using D ‐alanine as amine donor. α‐Tetralone, which was the only substrate not accepted by HN‐ωTA, ArR‐ωTA, and AT‐ωTA, was successfully transformed with perfect enantioselectivity (ee >99%) into the corresponding optically pure amine employing the variant ArRmut11‐ωTA.     

Cobalt‐Catalyzed Direct Amination of Arenes with Alkylamines via Bidentate‐Chelation Assistance

Cobalt‐catalyzed C−H amination of arenes with alkylamines by the assistance of 8‐aminoquinoline as auxiliary through sp² C−H bond functionalization has been achieved. Attractive features of this protocol include the low loading of the cobalt catalyst and the readily available reagents.