Authors:Bijan Barghi, Moslem Fattahi, and Farhad Khorasheh
highly dependent on the supply/demand situation for both propylene and ethylene. It is expected that in order to meet future propylene demand, new processes such as catalytic propane dehydrogenation (PDH) will be developed. The PDH reaction is reversible
In recent years, oxidative dehydrogenation of propane (ODP) has been intensively investigated because of its significant advantages over the dehydrogenation process, which is presently utilized for producing alkene
Authors:B. V. Lebedev, V. G. Vasil'yev, and N. N. Novosyolova
The heat capacityCpo of polypropanal was studied in a vacuum adiabatic calorimeter between 11 and 330 K, and in an ADKTTM automatic differential calorimeter from 320 to 370 K. The thermodynamic parameters of melting and glass transition of polypropanal were also determined. From the results, the thermodynamic functions of the polymer were calculated in the range 0 K to 360 K. The enthalpy of depolymerization of polypropanal to the starting monomer was measured in a DAK-1-1 differential automatic microcalorimeter. From the results of this study and literature data on the thermodynamic properties of propanal., the enthalpy, entropy and Gibbs function of bulk polymerization of propanal were estimated from 0 K to 330 K. Ceiling limiting temperatures of transitions of the liquid monomer to crystalline and high-elasticity polymer were determined.
Authors:Y. Shi, L. Sun, F. Tian, J. Venart, and R. Prasad
The transient hot-wire technique is widely used for absolute measurements of the thermal conductivity of fluids. Refinement
of this method has resulted in a capability for accurate and simultaneous measurement of both thermal conductivity and thermal
diffusivity together with a determination of the specific heat. However, these measurements, especially those for the thermal
diffusivity, may be significantly influenced by fluid radiation.
The present work investigates the effect of fluid radiation on the measurements of the thermal conductivity of propane. Recently
developed corrections have been used to examine this assumption and rectify the influence of even weak fluid radiation. Measurements
at 372 K with a hot-wire instrument demonstrate the presence of radiation effects in both the liquid and vapor phase. The
influence is much more pronounced in liquid propane at 15.5 MPa than in the vapor phase at 881.5 kPa. The technique employed
to obtain radiation-free thermal conductivity measurements is described.
The use of mixed γ- and χ-phase Al2O3 as supports for preparation of Pt/Al2O3 catalysts resulted in higher acidity of Al2O3 and higher Pt dispersion compared to the pure phase supports. As a consequence, higher propane oxidation activities were
Authors:R. Anouchinsky, A. Kaddouri, and C. Mazzocchia
A novel preparation methodology of NiMoO4 catalysts is described, consisting in immobilizing a precursor aqueous solution containing Ni and Mo ions by gelation with agar. Compared with other precursors prepared by coprecipitation, the gel, on heating, begins to crystallize at a very low temperature, with the collapse of the gel structure.
Authors:A. Kaddouri, R. Del Rosso, C. Mazzocchia, and D. Fumagalli
Isothermal reduction under hydrogen of polymorphic NiMoO4 system has beenstudied at different temperatures using thermogravimetry. Evidences found by TG (oxygen depletion rate) have shown a dependence on lattice oxygen mobility and source due to the crystal structure and temperature.Relative to the undoped NiMoO4 phases, it has been found that the presence of K2O, CaO and P2O5 promoters simultaneously affects both the reduction rate and the oxygen source.Monolayer lattice oxygen mobility of undoped and doped NiMoO4 material was investigated by oxydehydrogenation of light alkanes performed by using a periodic flow micro-reactor. The alkane activity has been found to be linked to the reduction behaviour of the different undoped and doped NiMoO4 phases.