Papers by Keyword: Catalysis

Abstract: Graphene, a two-dimensional carbon material, has attracted tremendous research interest in recent years due to its exceptional properties, such as excellent electrical, mechanical and thermal properties. Meanwhile, various kinds of novel functional materials based on Graphene oxide are employed in different fields like solar cell, sensor and catalysis. With the increasing number of catalysts during synthesizing graphene-based composites, the development of catalysis science and technology will surely be promoted. This paper reviews recent advances in the preparation and structure of graphene oxide, especially its applications in catalysis fields.

Abstract: N-methyl pyrrolidonium hydrosulfate ([Hnmp]HSO₄) was synthesized and characterized. N-butyl acetate was synthesized from acetic acid and n-butanol with [Hnmp]HSO₄ as catalyst in a catalytic rectification column 30 mm in diameter and 2.5 m in height. Effects of catalyst dosage, bottom temperature, feeding ratio of acetic acid to n-butanol, feeding method and reflux ratio on esterification and rectification were investigated. Under optimal condition which taking both energy cost and product quality into account: catalyst dosage was 0.5% of feed weight, bottom temperature was 120 °C, mole ratio of acetic acid to butanol was 1:1.2, acetic acid and butanol were mixed and fed above second section of packing, feeding rate was 150 mL/h and reflux ratio was 4, mass fraction of n-butyl acetate in bottom could reach 92.49 %.

Abstract: The dissociation phenomena of H2 molecule on Pt(111) surface was simulated by Molecular Dynamics (MD) method and the effect of motion of the gas molecule or surface atoms on dissociation phenomena was analyzed in detail. The Embedded Atom Method (EAM) was used to model the interaction between an H2 molecule and Pt(111) surface. Using this potential, simulations of an H2 molecule impinging on a Pt(111) surface were performed and the characteristics of the collision were observed. Using MD data the dynamic dissociation probability were obtained and compared with the static dissociation probability to analyze the effect of atomic motion on dissociation phenomena.

Abstract: Ethyl acetate was synthesized using inorganic salt as catalyst. The catalytic syntheses of Ethyl Acetate using NaHS04, Sncl2 and Fecl3 as catalysts were introduced. It showed that Sncl₂ was excellent catalysts for synthesis Ethyl Acetate with higher yields and the catalyst can be reused, and the reaction does not cause pollution.

Abstract: Ammonia production is a capital-intensive industry as it requires high temperature (400-500oC) and also high pressure (150-300 bar) for its daily operations. An earnest effort was made to synthese ammonia gas using an in-house designed microreactor. The production of ammonia was carried out in a magnetic field reaction zone, with the reaction temperature of 30°C - 280°C and ambient operation pressure. Mn0.8Zn0.2Fe2O4 nanoparticles, synthesized using the sol gel method, were used as the catalyst for the ammonia synthesis. XRD confirmed the single phase ferrites and FESEM images revealed nanofibre-like morphology when sintered at 700oC in argon gas. Electron diffraction was performed using HRTEM and obtained diffraction patterns confirmed the crystal structure of the catalyst. By using the Kjeldahl method it was found that the reaction carried out in 1 Tesla magnetic field gave approximately 46% ammonia yield. The proposed new method could be appealing for ammonia manufacturers due to highly economical implication which may offer urea producers a potential contender in the competitive market place.

Abstract: The main properties of tourmaline are far infrared radiation, spontaneous polarization, widely used in the fields of saving energy and environment. Tourmaline as catalyst have extensive applications in the fields of environmental protection, fuel combustion, air purification, printing, deodorant, antibacterial, as well as wastewater treatment of dyeing and aquaculture.

Abstract: Heterogeneous acid catalyst, H4SiW6Mo6O40/SiO2 was synthesized by a sol-gel technique. Catalytic application of the catalyst for synthesis of acetals and ketals were tested. The variation of different reaction parameters on the yield of acetals and ketals were also studied. The yields of acetals and ketals can reach 80.0%~96.9% at the optimized conditions. The high activity and stability of the catalyst is well retained after 4 runs. The results reveal that the H4SiW6Mo6O40/SiO2 catalysis is a novel, effective and reusable catalyst for synthesizing actetals and ketals.

Abstract: The paper has studied the process of using H₂O₂ as oxidant and tungsten acid as catalyst, catalytic oxidation synthesis process of cyclopentene to glutaraldehyde and explored the main influence factors of the reaction, including the reaction time, reaction temperature, catalyst dosage and solvent. Furthermore, the quantitative analysis and qualitative analysis of the product was characterized by gas chromatography. The optimum synthetic condition was as follows: tertiary butanol as solvent, tungsten acid: boron anhydride(mass ratio)=1:1, 30%H₂O₂ as oxidant, the reaction temperature 35°C, the reaction time 4h, the yield of glutaraldehyde yield was 46%.

Abstract: The newly sulfated nanosolid superacid TiO₂/SO₄ prepared by sol-gel method was broadly characterized by acid base titration, XRD and TEM, which identified that the superfine solid TiO₂/SO₄ showing good dispersibility with average size of 27 nm belongs to kind of crystalline nanoparticles. With the help of the catalyst TiO₂/SO₄, the optimal reaction condition for direct transformation of pyrazole and nitrosonitric acid into 3, 5-Dinitropyrazole was n (pyrazol)=0.10 mol, m (TiO₂/SO₄ )＝1.5g, V(n-octannol)＝90mL, and V(nitrosonitric acid)＝50mL. Moreover, the optimal yield of the catalytic reaction reached up to 59.4% when the reaction time is 7 hours. The nanosolid superacid catalyst is still of high activity after regenerating eight times by calcination at 600^。C.

Abstract: Under the catalysis of Co metal, the nanosized titania could be grown on Ti substrate at elevated temperature under a gas mixture of N₂, O₂, CH₄ , and H₂O. The nanosized titania was characterized by scanning electron microscope for its morphology, and by an energy dispersion spectrometer for its composition. The results showed that the straight and long titania nanowire could be formed at 900°C under a gas mixture of N₂, O₂, and CH₄. When H₂O vapor was added to the gas mixture, the titania nanowire became somewhat curved. The tiania nanowire was oxygen deficient, i.e. TiO_2-X.