Thermal degradation of two liquid fuels and detonation tests for pulse detonation engine studies

The use of liquid fuels such as kerosene is of interest for the pulse detonation engine (PDE). Within this context, the aim of this work, which is a preliminary study, was to show the feasibility to initiate a detonation in air with liquid-fuel pyrolysis products, using energies and dimensions of test facility similars to those of PDEs. Therefore, two liquids fuels have been compared, JP10, which is a synthesis fuel generally used in the field of missile applications, and decane, which is one of the major components of standard kerosenes (F-34, Jet A1, ...). The thermal degradation of these fuels was studied with two pyrolysis processes, a batch reactor and a flow reactor. The temperatures varied from 600°C to 1,000°C and residence times for the batch reactor and the flow reactor were, respectively, between 10–30 s and 0.1–2 s. Subsequently, the detonability of synthetic gaseous mixtures, which was a schematisation of the decomposition state after the pyrolysis process, has been studied. The detonability study, regarding nitrogen dilution and equivalence ratio, was investigated in a 50 mm-diameter, 2.5 m-long detonation tube. These dimensions are compatible with applications in the aircraft industry and, more particularly, in PDEs. Therefore, JP10 and decane were compared to choose the best candidate for liquid-fuel PDE studies. This paper was based on work that was presented at the 20th International Colloquium on the Dynamics of Explosions and Reactive Systems, Montreal, Canada, July 31 – August 5, 2005.     

Rheological properties of binary associating polymers

Dynamics of associating polymer solutions above the reversible gelation point are studied. Each macromolecule consists of a soluble backbone (B) and a small fraction of specific strongly interacting groups (A or C stickers) attached to B. A mixture of B–A and B–C associating polymers with 1:1 stoichiometric ratio is considered. As a result of AC association, the polymers reversibly gelate above the overlap concentration. It is shown that (1) the network strands are linear complexes (double chains) of B–A and B–C; (2) “diffusion” of the network junction points is characterized by an apparent activation energy, which can be significantly higher than the energy of one AC bond; (3) most importantly, the randomness of sticker distribution along the chain can significantly slow down the network relaxation leading to a markedly non-Maxwellian viscoelastic behavior. The theory elucidates the most essential features of rheological behavior of polysaccharide associating systems (with A = adamantyl moiety, C = β-cyclodextrin, B = either chitosan or hyaluronan) including similar behavior of G ^′ and G ^″ in a wide frequency range, strong temperature dependence of the characteristic frequency ω _x , and an extremely strong effect of added free stickers (fC) on the dynamics. This paper was presented at Annual European Rheology Conference (AERC) held in Hersonisos, Crete, Greece, April 27–29, 2006.     

Equilibria in complexes of N-heterocyclic molecules,part XII. The reaction of hydroxide and alkoxide Ions with platinum(II) complexes of 5-nitro-1,10-phenanthroline and 2,2′-bipyridyl

Summary Bis-(5-nitro-1,10-phenanthroline)platinum(II) dichloride and diperchlorate have been prepared. The reaction between the parent cation and hydroxide ion has been studied using 1 FI n.m.r. spectroscopy and found to involve attack at the ligand. The bis-(2,2-bipyridyl)platinum(II) ion has been shown to be highly reactive towards methoxide ion. The dissociation of a 2,2-bipyridyl ligand is preceded by attack at the ligand.Part XI: R. D. Gillard, t.. A. P. Kane-Maguire and P. A. Williams,Transition Met. Chem., 2, 47 (1977).On leave from the University of Baghdad, Iraq.     

Addition of hydroxide to an isoelectronic series of bis-diazineplatinum(II) complex ions

Base hydrolysis of bis-bipyridylplatinum(II) occurs via a 1:1 intermediate adduct with hydroxide ion. The equilibrium constants for this 1:1 addition of hydroxide inwater to complex ions [PtL2]2+, where L=one of theisoelectronic set 2,2-bipyridyl (bpy); 2,2- bipyrazine (bpz); 3,3-bipyridazine (bpdz) and 2,2- bipyrimidine (bpym) are respectively (as log10K at 25°C): 4.23; 4.59; 3.82; 6.14. This result is rationalized in terms of addition at the 6–position of the ligand.     

Mise en evidence de la formation de R2MMR2 a partir de disila-1,2 et digerma-1,2 cyclohexenes-4

Intermediates with π-bonded Si or Ge are generated during gas phase pyrolysis of 1,2-disila- or 1,2-digerma-cyclohex-4-enes.Compounds such as R₂MMR₂ are successfully trapped by addition or [2 + 2] and [4 + 2] cycloadditions. These results were proved by mass spectrometry.     

Hydrolysis of oligosaccharides by polyelectrolytes

The hydrolysis of maltotriose, maltose, cellobiose and gentiobiose, at a concentration of 1% (w/v), have been investigated in 0.20 N sulphuric acid and 0.2 N polystyrene sulphonic acid. The apparent rate constants determined by high pressure liquid chromatography are compared and their dependence on temperature is given. The thermodynamic parameters of reaction with both acids are deduced. The catalytic effect of the polyacid, expressed by the ratio of the rate constants at a given temperature, is discussed in terms of the condensation of the counterions.     

Equilibria in complexes ofN-heterocyclic molecules,part XXXI. an explanation for rates of dissociation of iron(II) complexes of diimine ligands

Summary [Fe(3,3'-bipyridazine)₃]²⁺ has a negligible rate of dissociation in water at pH 7, and in 0.05 mol dm^–3 HO^– at ionic strength 1.00 mol dm^–3 (NaNO₃) at 298.2 K, the second-order rate constant involving HO_– is only 3.3 x 10^–5 dm³ mol^–1 s^–1. Examination of kinetic and other data and results for it wide variety oftris-diimine complexes of Fe^II related compounds, indicates that dissociation takes placevia attack at the ligand. The significance of the various possible intermediates is assessed and it is evident that a previously postulated intramolecular transfer of HO^– from the ligand to the metal atom, with associated metal-nitrogen bond fission, is important in the reaction. A general scheme for dissociation of these kinds of compounds is set out.Part XXX: R. D. Gillard, R. P. Houghton and J. N. Tucker,J. Chem. Soc., Dalton Trans., submitted for publication.Present address: Department of Chemistry. University of Nottingham, University Park, Nottingham NG7 2RD U.K.     

The use of pyridine-2-azo-p-dimethylaniline as an indicator in glacial acetic acid

Pyridine-2-azo-p-dimethylaniline is suggested as an indicator in the titration of amines (aniline, butylamine, p-phenylenediamine and ethylenediamine) with perchloric acid in glacialacetic acid medium. The precision obtainable is much better than that with crystal violet indicator. The pyridine dye can also be used satisfactorily in the titration of sodium carbonate and sodium acetate.     

Separation des alcalino-terreux par l'edta sur resine echangeuse d'ions

The quantitative separation of a few mg of strontium and barium from several g of calcium is described. The alkaline earth carbonates are dissolved in 0.1 M EDTA, fixed at pH 4.8 on an ammoniacal Dowex column, and eluted, also with 0.1 M EDTA, calcium at pH 5.25, strontium at pH 6.0, barium at pH 9.0. The end of the calcium elution can be followed accurately by a sudden pH increase in the eluate(from 4.8 upto 5.25).     

Equilibria in complexes ofN-heterocyclic molecules,Part XXIV. The reaction of nucleophiles with tris-(2,2′-bipyrimidine)iron(II) ion and its ruthenium(II) analogue

Summary The reactions of [Fe(bipym)₃]²⁺ and [Ru(bipym)₃]²⁺ with hydroxide ion in aqueous solution have been followed. The [Ru(bipym)₃]²⁺ species undergoes nucleophilic attack at the ligand to yield [Ru(bipym)₂(pyrimidine)(OH)]⁺ and [HCO₂]^– ion, involving cleavage of one pyrimidyl ring. Intermediates can be observed in the reaction of [Fe(bipym)₃]²⁺ with HO^–, N₃ ^– and SCN^–. The kinetics of the first reaction have been followed and the results are compared with those known for the reactions of [Fe(bipy)₃]²⁺, [Fe(phen)₃]²⁺ and similar compounds.Part XXIII: P. A. Williams,Transition Met. Chem., 78/84.