Zhentao Mi

Thermal stability and kinetic of decomposition of nitrated HTPB.

Nitrated HTPB (NHTPB) is a potential energetic binder to replace the conventional inert binder, HTPB, for the composite solid propellants and plastic bonded explosives (PBXs). The thermal stability of the NHTPB sample with 10% double bonds converted to dinitrate ester group (10% NHTPB) was evaluated by high-pressure differential scanning calorimeter (PDSC) measurement. The influences of pressure (0.1, 2.5 and 5.0 MPa) and the heating rate (4, 6, 8 and 10 degrees C min(-1)) on the DSC behavior of the 10% NHTPB sample were investigated. The decomposition temperature of this compound decreased with the increase of pressure, meanwhile, increased as the heating rate increasing. The thermal decomposition at 150-250 degrees C followed a first-order law. The kinetic parameters and thermodynamic parameters for the 10% NHTPB sample at 150-250 degrees C under ambient pressure were obtained from the DSC data by non-isothermal methods proposed by ASTM E698 and Flynn-Wall-Ozawa. The critical temperature for this compound was estimated at about 154 degrees C.

Effects of organic solvents on the structure stability of TS-1 for the ammoximation of cyclohexanone

The effects of organic solvents on the ammoximation of cyclohexanone to cyclohexanone oxime with H2O2and NH3 over TS-1 were studied. To investigate the effects of ammonia and organic solvents on the structure stability of the catalyst, TS-1 samples were pretreated under severe conditions in ammonia solution or ammonia solution plus methanol, toluene or t-butanol, respectively, and then characterized bySEM, XRD, FTIR, etc. The results revealed that t-butanol is the best solvent for the ammoximation reaction; ammonia tends to destroy the active sites, -Ti-O-Si- structure in TS-1, but the presence of organic solvents remarkably limits this damaging effect of ammonia.

Greener synthesis route for Jet Propellant-10: the utilization of zeolites to replace AlCl3

This paper summarizes our recent developments in the utilization of H-type zeolites to replace AlCl3 in exo-tetrahydrodicyclopentadiene production. H-type Y zeolites with large pore size (0.74 nm) had sufficient activities for isomerization of endo-tetrahydrodicyclopentadiene (endo-THDCPD) to form exo-tetrahydrodicyclopentadiene (exo-THDCPD). As for acidity strength, the moderate strength of zeolite acidity was favorable. The incorporation of fluorine generated more moderate acids, which improved the catalytic performance of zeolites to exo yield = 92.58%, exo selectivity = 96.47%, and suppressed the adamantane (ADM) yield = 2.32%. When NH4F/SSY = 6.57%, calcined at 500 °C, this showed an equivalent performance as AlCl3.

Effects of lanthanum addition on Ni-B amorphous alloy catalysts used in anthraquinone hydrogenation

Amorphous Ni-B alloys with or without lanthanum were prepared by KBH4 reduction, characterized by ICP, BET surface area measurement, XRD, TPD, H2 chemisorption, etc., and studied in the hydrogenation of anthraquinone. The addition of lanthanum chloride in the preparation procedure leads to the incorporation of lanthanum oxide and the decrease of Ni:B ratio in the Ni-B amorphous alloy. In comparison with Ni-B, the presence of lanthanum oxide in the amorphous alloy lead to higher BET area, higher extents of H2 chemisorption and desorption, the shift of H2 desorption peaks to lower temperatures, and higher TOF and reaction rate in the hydrogenation of anthraquinone. The effects of lanthanum were attributed to its dispersion of Ni, leading to much more active centers and the donation of electrons to Ni and therefore activating the adsorbed hydrogen and weakening the binding energy between nickel and hydrogen. As a result, both TOF and the reaction rate in the hydrogenation of anthraquinone were increased with the addition of lanthanum.

Study on deactivation and regeneration of Pd/Al2O3 catalyst in hydrogen peroxide production by the anthraquinone process

Deactivated palladium catalysts in the hydrogenation of anthraquinione were regenerated with ethanol, nitric acid, hydrogen peroxide, boiling water and steam, respectively. The deactivated and regenerated catalysts were characterized by XPS, ICP, TG, FTIR, TPD, XRD, etc., and studied in the hydrogenation of anthraquinone. The results showed that the main cause of catalyst deactivation is the coverage of the active component by deposits. The treatments by hydrogen peroxide and boiling water can effectively regenerate the deactivated catalysts.

GAS-AGITATED LIQUID AND OXIDATIVE EXTRACTION IN THE ALKYL ANTHRAQUINONE PROCESS FOR THE PREPARATION OF HYDROGEN PEROXIDE

As preliminary investigations on oxidative extraction in the alkyl anthraquinone process for the production of hydrogen peroxide, the air-agitated liquid extraction of hydrogen peroxide from the working solution was studied and the dynamics of the extraction was measured as a function of the oil/water ratio and gas flow rate. The investigations were carried out either in an empty column or in a packed column. The results proved that the use of gas-agitated oxidative liquid extraction was a good way to integrate the oxidative operation unit with the extraction unit in the alkyl anthraquinone process for the preparation of hydrogen peroxide.

Thermal oxidative stabilities of endothermic fuel model compounds with pressure different scanning calorimeter

Thermal -oxidative stabilities of hydrocarbons in the jet fuels were studied using pressure different scanning calorimeter (PDSC) . Apparent active energies of thermal oxidative reaction for twelve hydrocarbon s were reported with Flynn -Wall -Ozaw method. It is concluded that the PDSC is a rapid and reliable technique to characterize the thermal oxidative stability of jet fuel and to evaluate performance of fuel additives.

Intrinsic kinetic study on the oxidation of 6-pentyl-1,2,3,4-tetrahydroanthacene-9,10-diol

A new working solution consisting of 2-pentylanthraquinone (PAQ) and 6-pentyl-1,2,3,4-tetrahydroantraquinone (4HPAQ) was hydrogenated and then oxidized by O2 to produce H2O2. The oxidation reaction was conducted in a well-stirred batch reactor at 30~50oC and 0.10~0.20 MPa. By measuring the concentrations of generated H2O2 by iodometry, the intrinsic kinetics for the gas-liquid oxidation of 6-pentyl-1,2,3,4-tetrahydroanthacene- 9,10-diol (4HPAQH2, the only hydrogenated product in the hydrogenated working solution) with molecular oxygen were studied. An exponential model was employed to describe the reaction rate and the kinetic parameters were obtained. The results show that the reaction rate is 0.7 and 1.4 order in the concentration of 4HPAQH2 and oxygen pressure respectively, and the activation energy for oxidation is 41.3 kJ/mol.