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1
Content available Effect of Some Chemical Additives in Increasing the Electrical Conductivity of the Liquid Fuel Dimethyl Aminoethyl Azide (DMAZ)
Pakdehi Shahram G., Taffazolinia Hamidreza, Rezaei Sajjad, Fathollahi Manoochehr
Central European Journal of Energetic Materials
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2022
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Vol. 19, no. 3
265--280
EN
The novel liquid fuel 2-dimethylaminoethyl azide (DMAZ) is a good candidate for the replacement of the hydrazine family in space programs. However, it suffers from low electrical conductivity, which is dangerous during the production process and its transportation. A simple and effective way to increase its electrical conductivity is the use of antistatic additives. In this article, the electrical conductivity of DMAZ was initially predicted via an artificial neural network. Then, the increase in electrical conductivity of DMAZ was investigated using some chemical surfactants (such as hexylamine, octylamine and tributylamine), acetonitrile as a polar aprotic substance and a DMAZ salt (DMAZ·HCl) as an ionic liquid. Of these additives, acetonitrile had the greatest effect on the electrical conductivity of the fuel, exhibiting an increase in conductivity of about 45%. Adding a two-component mixture of acetonitrile and the DMAZ salt, further increased the electrical conductivity of the fuel by about 55%, relative to pure DMAZ. Tributylamine did not have a significant effect on the electrical conductivity of the fuel.
2
Content available Batch extractive distillation of mixture methanol-acetonitrile using aniline as a asolvent
Li G., Yu Y., Bai P.
Polish Journal of Chemical Technology
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2012
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Vol. 14, nr 3
48-53
EN
Methanol and acetonitrile form a minimum azeotrope at 336.74 K, which contains methanol 76.89 mas%. The simulation and the experiment to separate the mixture by batch extractive distillation using aniline as entrainer is performed. Based on the experimental and simulative VLE data, aniline is chosen to be the suitable solvent. The sensitivity analysis about the number of stages, the refl ux ratio, the solvent feed stage and the solvent fl ow rate is conducted to obtain the optimal parameters and confi guration of the extractive distillation column with minimal energy requirements. The most appropriate confi guration is 30 theoretical stages. The optimal entrainer feeding stage is 8 with a solvent fl ow rate of 20kg/h and the refl ux ratio of 2.0, respectively. The simulation results show the effect of the main variables on the extractive distillation process. The experiment is carried out to corroborate the feasibility of the separation of methanol-acetonitrile by batch extractive distillation.
3
NMR Evidence for Protonated Tetraethyl p-tert-Butylcalix[4]arene Tetraacetate
Kriz J., Dybal J., Makrlik E., Vanura P.
Polish Journal of Chemistry
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2007
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Vol. 81, nr 7
1321-1326
EN
In addition to well-known complexes of tetraethyl p-tert-butylcalix[4]arene tetraacetate (abbrev. 1) with alkali metal cations, an equimolar complex of this compound with H3O+, i.e. 1źH3O+, was found to be formed slowly in acetonitrile, however, with a very high equilibrium constant, the value ofwhich is beyond the possibilities of exact determination by NMR. Hydrogen bis(1,2-dicarbollyl) cobaltate (HDCC) was used as a proton source. Further, by a combination of 1D and 2D 1H NMR with 13C NMR spectra, it was proved that the ester carbonyls of 1 are not strongly involved in coordination of H3O+. It means that the most probable structure of the 1źH3O+ complex is obviously that with H3O+ bound by strong hydrogen bonds to the phenoxy oxygen atoms of 1.
4
Conductance Study of the Thermodynamics of Dibenzo-21-crown-7 Complexes with Na+, K+, Rb+ and Cs+ Ions in Acetonitrile Solution
Shamsipur H., Zare K., Shamsipur H.
Polish Journal of Chemistry
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2006
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Vol. 80, nr 10
1755-1755
EN
A conductance study of the interaction between Na+, K+, Rb + and Cs+ ions and dibenzo-21-crown-7 in acetonitrile solution has been carried out at various temperatures. The formation constants of the resulting 1:1 complexes were determined from the molar conductance-mole ratio data and, in the entire temperature range, found to vary in the order Rb+ >K+>Cs+>Na+. The enthalpy and entropy of complexation reactions were determined from the temperature dependence of the formation constants. In all cases, the resulting complexes were found to be both enthalpy and entropy stabilized.
5
Conductance Study of the Thermodynamics of Dibenzopyridino-18-crown-6 Complexes with K+, Ti+, Sr2+ and Ba2+ Ions in Acetonitrile Solution
Shamsipur M., Tavakkoli N.
Polish Journal of Chemistry
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2004
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Vol. 78 / nr 1
109-116
EN
The complexation reactions between dibenzopyridino-18-crown-6 and Tl+, K+, Sr2+ and Ba2+ ions were studied conductometrically in acetonitrile solution at various temperatures. The formation constants of the resulting 1:1 complexes were calculated from the computer fitting of the molar conductance-mole ratio data at different temperatures. At 25°C, the stability of the resulting complexes varied in the order Ba2+ > Sr2+ > Tl+ > K+. The enthalpy and entropy changes of the complexation reactions were evaluated from the temperature dependence of formation constants. While, the bivalent alkaline earth complexes are both enthalpy and entropy stabilized, the univalent cation complexes used are enthalpy stabilized but entropy destabilized.
6
Termodynamic Study of the Interaction Between Some Recently Synthesized Benzo-Substituted Macrocyclic Diamides with Some Pyridinium Ion Derivatives in Acetonitrile Solution
Ganjali M., Zargazi M. H., Mohajeri A.
Polish Journal of Chemistry
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2001
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Vol. 75, nr 5
743-749
EN
The formation of pyridinium, 2-methyl pyridinium, 2,4-dimethyl pyridinium and 2,4,6- trimethyl pyridinium complexes with the some recently synthesized benzo-substituted macrocyclic diamides was investigated conductometrically in acetonitrile solution at various temperatures. The formation constants of the resulting 1:1 complexes were determined from the computer fitting of the molar conductance-mole ratio data. In all cases studied, the stability of complexes decreases in the order Py+ > 2m-Py+ > 2,4dim-Py+ > 2,4,6trim-Py+. The enthalpy and entropy of complexation reaction were determined from the temperature dependence of the formation constants. In all cases, the complexes were enthalpy stabilized but entropy destabilized.
7
Content available remote The influence of the H/D substitution on the viscosity in acetonitrile-decanol solution near the critical point
Milewska A., Szydłowski J.
Nukleonika
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1999
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Vol. 44, nr 1
31-38
EN
Results of measurements of the temperature and concentration dependence of the kinematic viscosity of the mixture of acetonitrile/decanol, acetonitrile-d [indeks dolny]3 /decanol and acetonitrile/decanol-d using an optoelectronic capillary viscometer are reported. In all cases very weak divergence of the viscosity is observed while approaching the critical point. Concentration dependences also show weak anomalous behavior in the close vicinity of the critical temperature. Large isotope effect on viscosity is found and shortly discussed.
PL
W pracy przedstawiono wyniki pomiarów lepkości w mieszaninach acetonitryl-dekanol, acetonitryl-d [indeks dolny]3 - dekanol i acetonitryl - dekanol-d. Pomiary obejmują szeroki zakres temperatur ze szczególnym uwzględnieniem otoczenia punktu krytycznego. We wszystkich przypadkach obserwuje się słabe anomalie w temperaturowych i stężeniowych zależnościach lepkości kinematycznej. Obserwuje się znaczny wpływ podstawienia deuterem, malejący wraz ze zbliżaniem się do punktu krytycznego.
8
Electrochemical studies of 1,8-dihydroxy-9,10-anthraquinone derivatives in acetonitrile
Salimi A., Tamaddon F., Sharghi H., Mousavi M.F., Golabi S.M., Shamsipur M.
Polish Journal of Chemistry
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1998
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Vol. 72, nr 12
2573-2582
EN
The electrochemical reductions of some recently synthesized 1,8-dihydroxy-9,10-anthraquinone derivatives in acetonitrile were investigated. In the absence of proton donors, the anthraquinones reduced in two successive one-electron steps. The first step is reversible or nearly reversible, while the second step is quasireversible or irreversible, depending on the electrode used. The influence of molecular structure on the reduction potential is addressed. The diffusion coefficients of the anthraquinone derivatives were determined from chronoamperometric measurements on the GC, Au and Pt electrodes. The heterogeneous electron transfer rate constants and charge transfer diffusion coefficients were evaluated from rotating disc voltammetry measurements. Depedence of the rate constants on the anthraquinone structure and the electrode materials is discussed.
9
Content available remote Acetonitryl
Majka J.
Podstawy i Metody Oceny Środowiska Pracy
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1998
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Nr 18
33--48
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