用于甲烷水蒸气重整的镍基催化剂的失活和再生

The deactivation of nickel catalysts used in Arak and Razi petrochemical complexes followed by catalyst regeneration was evalu-ated. The characterization of the different structures was made by powder X-ray diffraction(XRD),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),transmission electron microscopy(TEM),and carbon & sulfur analyzer. The Ni particle size was estimated from XRD patterns and TEM graphs. The agglomeration of nickel particle and the poison by sulfur components were recognized as the main reasons in deactivation of Arak and Razi catalysts,respectively. The activity of the used catalysts before and after regeneration was measured on methane steam reforming at a CH4:H2O ratio of 1:3 at 850 oC. The regeneration processes for Arak and Razi samples were performed with CO2 as an oxidative atmosphere and steam as a regenerating agent,respectively. The results show that,(1) no residual sulfur components were on the regenerated Razi catalyst surface without changing the structure of the catalyst and the regenerated catalyst has gained 80% of its catalytic activity,and that(2) the nickel particle size of regenerated Arak specimen decreased remarkably as measured by Debye-Scherrer equation from XRD patterns. TEM images were in agreement with the XRD results and indicated a decrease in nickel particle size of regenerated catalyst. Additionally,in both regenerated catalysts all the coke on the surface of the support was eliminated after regeneration.     

Microwave‐induced Stereoselectivity in Synthesis of trans‐4‐Aryl‐3‐methyl‐6‐oxo‐4,5,6,7‐tetrahydro‐2H‐pyrazolo[3,4‐b]pyridine‐5‐carbonitriles

A facile synthesis of trans isomers of 4‐aryl‐3‐methyl‐6‐oxo‐4,5,6,7‐tetrahydro ‐ 2H ‐ pyrazolo[3,4‐b]pyridine‐5‐carbonitriles via three‐component condensation reaction of an aldehyde, 3‐amino‐5‐methylpyrazole and ethyl cyanoacetate in acetonitrile has been developed under microwave irradiation. This one‐pot reaction proceeds without any catalyst in short times and gives the product in high selectivities and high yields.     

Catalytic synthesis of coumarin-linked nicotinonitrile derivatives via a cooperative vinylogous anomeric-based oxidation

Research on Chemical Intermediates - In the presented study, we developed a new and efficient strategy for the synthesis of coumarin-linked nicotinonitrile derivatives via a cooperative vinylogous...     

Magnetic nanoporous MCM‐41 supported ionic liquid/palladium complex: An efficient nanocatalyst with high recoverability

In this study, a novel magnetic mesoporous MCM‐41 silica supported ionic liquid/palladium complex (Fe₃O₄@MCM@IL/Pd) with core‐structure was prepared and characterized and its catalytic performance was developed under green conditions. The Fe₃O₄@MCM@IL/Pd was prepared via a post grafting method and was characterized using Fourier transform infrared spectroscopy, thermal gravimetric analysis, wide‐ and low‐angle powder X‐ray diffraction, scanning electron microscopy, transmission electron microscopy, vibration sample magnetometer and energy‐dispersive X‐ray analyses. This was applied as an efficient and recoverable nanocatalyst for the one‐pot synthesis of pyrano[2,3‐d]pyrimidine derivatives under ultrasonic conditions. The catalyst was magnetically recovered and reused for 12 consecutive cycles without significant loss of its activity and selectivity.     

Designing of Parity Preserving Reversible Vedic Multiplier

International Journal of Theoretical Physics - Reversible logic is used in designing low-power CMOS circuits, optical information processing, and quantum computing. Moreover, using parity...     

Synthesis of new bis-benzylidene-hydrazides as a sensitive chromogenic sensor for naked-eye detection of CN¯ and AcO¯ ions

Some new bis-benzylidene-hydrazides were synthesized via a condensation reaction of the corresponding azo dyes with adipic acid dihydrazide. All compounds because of the three possible stereoisomers showed four sets of signals in NMR. The anion recognition studies exhibited that the nitro bis-benzylidene-hydrazide derivative acts as a highly sensitive and selective chromogenic sensor for naked-eye detection of CN¯ and AcO¯ ions, with a distinct color change from yellow to blue and yellow to purple, respectively. The limit of detection (LOD) was found for 1d toward CN¯ to be 1.1?μM. The result of the Job's plot indicated stoichiometry of binding between chemosensor and anions is found to be 1:2.     

Potential of Si14Ge14 and B14P14 nanocages as electrodes of metal-ion batteries: a theoretical investigation

Journal of Solid State Electrochemistry - In this study, the potential of Si14Ge14 and B14P14 as anode electrodes in metal-ion batteries by using of the density functional theory was investigated....     

Synthesis of a novel and reusable biological urea based acidic nanomagnetic catalyst: Application for the synthesis of 2‐amino‐3‐cyano pyridines via cooperative vinylogous anomeric based oxidation

In the current study, a novel and reusable biological urea based nano magnetic catalyst namely Fe₃O₄@SiO₂@(CH₂)₃‐urea‐benzimidazole sulfonic acid was designed and synthesized. The structure of the titled catalyst was fully characterized using several skills including Fourier transform infrared (FT‐IR) spectroscopy, energy dispersive X‐ray (EDX) analysis, X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermo gravimetric analysis/differential thermal analysis (TG/DTG) and vibrating sample magnetometer (VSM). Then, the catalytic performance of Fe₃O₄@SiO₂@(CH₂)₃‐urea‐benzimidazole sulfonic acid was successfully inspected towards the multicomponent synthesis of 2‐amino‐3‐cyano pyridine derivatives through a vinylogous anomeric based oxidation pathway.