Multidentate ligands for the synthesis of multi-metallic complexes

The reaction of the Schiff base species tris-((2-hydroxybenzylidene)aminoethyl)-amine (TrenSal) and tris-((2-hydroxy-5-bromobenzylidene)aminoethyl)amine (Tren5BrSal) with the acetates of nickel and zinc are reported. Two trimetallic complexes (M₃L₂) of Tren5BrSal with nickel and zinc have been crystallographically characterised. The attempted crystallisation of bis-(tris-((2-hydroxybenzylidene)aminoethyl)amine nickel) nickel from solutions containing TMEDA lead to the production of two novel complexes: namely a nickel adduct of the partially hydrolysed TrenSal ligand and an interesting nickel bromide–carbonate salt. [(TrenSal)₂Ni₃] is reacted with PbCl₂ to form a novel tetrametallic complex, [{(TrenSal)Ni}Pb(NC₅H₅)Cl]₂, where a Pb₂Cl₂ moiety replaces the nickel at the core of the complex. Extending the study to include the related hexadentate ligand, 1,1,1-tris-((2-hydroxybenzylidene)-aminomethyl)propane (TEtSal), we were able to isolate and characterise both [(TEtSal)₂Ni₃] and [{(TEtSal)Ni}₂Pb].     

Catalytic selective oxidation or oxidative functionalization of methane and ethane to organic oxygenates

Selective oxidation or oxidative functionalization of methane and ethane by both homogeneous and heterogeneous catalysis is presented concerning: (1) selective oxidation of methane and ethane to organic oxygenates by hydrogen peroxide in a water medium in the presence of homogeneous osmium catalysts, (2) selective oxidation of methane to formaldehyde over highly dispersed iron and copper heterogeneous catalysts, (3) selective oxidation of ethane to acetaldehyde and formaldehyde over supported molybdenum cat...     

乙烷在金属铁表面还原NO的实验研究

温度300~1 100 ℃时,由程序控温电加热水平陶瓷管反应器在N₂气氛和模拟气氛下,对乙烷在金属铁表面还原NO的特性进行了实验研究。结果表明,乙烷在金属铁表面能够高效地还原NO。在N₂气氛中,温度高于900 ℃时,乙烷在金属铁表面的脱硝效率超过95%。在模拟烟气条件下,当温度超过900 ℃,且过量空气系数小于1.0时,乙烷在金属铁表面还原NO的效率能够达到90%以上。相同条件下,乙烷在金属铁表面脱硝效率高于甲烷的脱硝效率。SO₂对乙烷在金属铁表面还原NO的效率影响可以忽略。对反应后的铁样品的组分进行了XRD表征,在此基础上对反应机理进行了分析。结果表明,在模拟烟气条件下NO的还原通过乙烷的再燃脱硝和金属铁直接还原两个机理完成。金属铁直接还原NO时生成的氧化铁则被乙烷还原为金属铁,从而使得金属铁能够持续对NO进行直接还原。乙烷再燃还原NO的中间产物HCN被氧化铁氧化为N₂,同时氧化铁也被HCN还原为金属铁。这一过程增强了NO的持续还原反应,同时避免了在燃尽时HCN二次氧化重新生成NO,从而保证了较高的NO还原效率。     

Thermal Decomposition Kinetics of Ethane Halides and Derivatives（C_2H_（6-n）X_n（n = 1～3）;X = F,Cl,Br）：DFT Study and NBO Analysis

A theoretical study of the thermal decomposition kinetics of ethane halides(C2H6-nXn(n = 1～3);X = F,Cl,Br) has been carried out at the B3LYP/6-31++G** and B3PW91/631++G** levels of theory.Among these methods and comparison of activation parameters with available experimental values,the B3PW91/6-31++G** method is in good agreement with the experimental data.The analysis of bond order and natural bond orbital(NBO) charges,bond indexes,and synchronicity parameters suggest the elimination of HX in reactions 1～9(HF:compounds 1～3,HCl:compounds 4～6,and HBr:compounds 7～9) occur through a concerted and slightly asynchronous four-membered cyclic transition state type of mechanism.     

乙烷质子传导膜燃料电池的极化与反应机理

制备了以乙烷作为燃料电池膜电极组装(MEA)及构建了单电池系统。研究了Nafion材料作为质子传导膜、Pt/C作为电极催化剂构成的燃料电池在105 ℃和0.4 MPa电化学性能。采用交流阻抗分析法、色谱分析法及根据Faraday定律,考察了电池的电极极化过程,确定了电池的反应产物并探讨了电极的电化学反应机理。研究结果表明,乙烷燃料电池内阻引起的欧姆极化很小,电池阴极的极化主要是欧姆极化过程所控制,阳极极化主要为活化和浓差过程控制,阳极极化比阴极极化显著,乙烷燃料电池的极化主要在阳极侧;在实验操作条件下,阴极反应产物为水,阳极反应的主产物为CO₂且含有少量的CO,电池反应产物不含乙烯。     

Zinc-containing zeolite catalysts for ethane aromatization prepared by solid-state modification

Solid-state modification was used to prepare zinc-containing zeolite catalysts based on pentasils with different framework SiO₂/Al₂O₃ ratios. The catalysts were studied by X-ray diffraction analysis and IR spectroscopy. The activity and selectivity of the Zn—pentasil systems prepared by the solid-state modification and impregnation methods were compared in the aromatization of ethane. The active and stable zeolite catalysts modified by transition metal ions can be obtained by the topochemical method.