HCl Reaction Research Articles

Quasiclassical trajectory calculations of the isotopic effect on cross-sections of reactions O(1D) + HCl (DCl, TCl)

The paper reports on a quasiclassical trajectory (QCT) study of the O(1D) + HCl (DCl, TCl) reactions, with emphasis on the isotopic effect on cross-sections and branching ratio. The calculations were performed on the ground 1 1 A' potential energy surface (PES). The cross-sections and branching ratios of the O(1D) + HCl (DCl, TCl) reaction have been calculated at the collision energies (E col) of 3–15 kcal/mol. Obvious differences have been found in the energy dependences of the reaction cross-sections and branching ratios among these isotopic reactions.

Novel technology for sewage sludge utilization: Preparation of amino acids chelated trace elements (AACTE) fertilizer

This study developed a novel technology for sewage sludge utilization. The bacteria proteins in the sewage sludge were extracted to produce the amino acid chelated trace elements (AACTE) fertilizer by virtue of several chemical processes. Firstly, the sewage sludge was hydrolyzed under hot hydrochloric acid solution to obtain protein solution. The effects of hydrolysis temperature, reaction time and pH on the extraction ratio of protein from the sewage sludge were investigated. Secondly, the protein solution was further hydrolyzed into amino acids under hot acid condition. The effects of the HCl dosage, hydrolysis temperature and reaction time on the yields of amino acids were investigated in detail. Thirdly, the raw amino acids solution was purified by activated carbon decolorization and glacial acetic acid dissolution. Finally, the purified amino acids were used to produce the AACTE fertilizer by chelating with trace elements. Results showed that, under optimum hydrolysis conditions, 78.5% of protein was extracted from the sewage sludge and the amino acids yield was 10–13 g per 100 g of dry sludge. The AACTE fertilizer produced was in accordance with China Standard for Amino Acids Foliar Fertilizer. This novel technology is more environmentally friendly compared with the conventional sludge treatments.

Cyanide- and carboxylate-functionalized cubic mesoporous silicas SBA-1: Synthesis, characterization and reactivity of organic functional groups

Highly ordered cubic ( Pm 3 ¯ n ) mesoporous silicas SBA-1 functionalized with a high density of cyanide and carboxylate groups were synthesized by one-pot co-condensation of tetramethoxysilane (TMOS) and 2-cyanoethyltriethoxysilane (CNTES) using cetyltriethylammonium bromide (CTEABr) as the structure-directing agent under strongly acidic conditions. A high degree of structural ordering is still retained up to 25 mol% CNTES loading (based on silicon) in the synthesis mixture. The simultaneous existence of chemically attached cyanide and carboxylate ester moieties was evidenced by solid-state 13C CPMAS (cross polarization magic angle spinning) NMR. The relative concentrations between cyanide and carboxylate ester functional groups in the resulting mesoporous silicas are strongly dependent on the synthesis parameters such as acid type, acid concentration and reaction time. By controlling these synthesis parameters, the contents of the cyanide functional groups incorporated can be tuned, and their transformation into carboxylate ester groups can be followed. With increasing HCl concentration and reaction time, the cyanide functional groups incorporated convert progressively into carboxylate ester groups after solvent extraction with an HCl/ethanol mixture. While using H 2SO 4 as an acid medium, on the other hand, the cyanide functional groups can be totally transformed into carboxylate ester groups. The generation of carboxylic acid functionalities can be achieved either by solvent extraction with only ethanol (without HCl) or post-dealkylation treatment of carboxylate ester groups in concentrated HCl. The acid type and concentration and the silicon source also have a profound influence on the particle morphology of mesoporous silicas.

Application of Interpolating Moving Least Squares Fitting to Hypervelocity Collision Dynamics: O(3P) + HCl

We use an automated interpolating moving least-squares (IMLS) algorithm, which generates a fitted ab initio surface for systems of arbitrary topology, to construct a global OHCl ((3)A'') surface at the UB3LYP/aug-cc-pVTZ level of theory. This analytic PES includes all reaction channels and OHCl geometries with energies up to 144 kcal/mol (6.25 eV) above the O + HCl asymptote. The fitted surface was combined with the quasiclassical trajectory method to study the dynamics of the O((3)P) + HCl reaction at hyperthermal collision energies. The fitted PES greatly improves energy conservation during trajectory integration and eliminates problems with ab initio convergence, which are often encountered during direct dynamics studies. The more extensive trajectory calculations yield new insight into the title reaction and agree well with previous experimental studies and direct dynamics results.

Leaching and kinetic modelling of low-grade calcareous sphalerite in acidic ferric chloride solution

The leaching kinetics of a low grade-calcareous sphalerite concentrate containing 38% ankerite and assaying 32% Zn, 7% Pb and 2.2% Fe was studied in HCl–FeCl 3 solution. An L 16 (five factors in four levels) standard orthogonal array was employed to evaluate the effect of Fe(III) and HCl concentration, reaction temperature, solid-to-liquid ratio and particle size on the reaction rate of sphalerite. Statistical techniques were used to determine that pulp density and Fe(III) concentration were the most significant factors affecting the leaching kinetics and to determine the optimum conditions for dissolution. The kinetic data were analyzed with the shrinking particle and shrinking core models. A new variant of the shrinking core model (SCM) best fitted the kinetic data in which both the interfacial transfer and diffusion across the product layer affect the reaction rate. The orders of reaction with respect to ( C Fe 3+ ), ( C HCl), and ( S/ L) were 0.86, 0.21 and − 1.54, respectively. The activation energy for the dissolution was found to be 49.2 kJ/mol and a semi-empirical rate equation was derived to describe the process. Similar kinetic behavior was observed during sphalerite dissolution in acidic ferric sulphate and ferric chloride solutions, but the reaction rate constants obtained by leaching in chloride solutions were about tenfold higher than those in sulphate solutions.

The interaction of disodium salt of 4,6-dinitro-1-oxobenzo-[6,5-c]-2,1,3-oxadiazolediol-5,7 with NaOH and HCl

Disodium salt of 4,6-dinitro-1-oxobenzo-[6,5-c]-2,1,3-oxadiazolediol-5,7 (I) was synthesized. The experimental dependences of the formation function on the solution pH were obtained by the potentiometric titration method for the reaction of NaOH and HCl with I, and the equilibrium constants for the above reactions were calculated. The reaction of I with HCl gives the acid sodium salt of 4,6-dinitro-1-oxobenzo-[6,5-c]-2,1,3-oxadiazolediol-5,7, which is the coordination compound with the Na+ cation. The title compound was studied by X-ray diffraction.

Reactivity and kinetic studies of (NH 4) 2(MoS 4) in acidic aqueous solution: Possible relevance to the angiostatic function of the [formula omitted] ligand

Although addition of mineral acids to WS 4 2 - in water is known to lead to aggregation and formation of various polynuclear thiotungstate anions, acid hydrolysis of the MoS 4 2 - anion is reported to give mainly MoS 3 or MoS 2 as hydrolysis products. Knowledge of the resulting product(s) from such reactions has implications on the use of tetrathiomolybdate ( MoS 4 2 - ) as both a potential anti-tumor drug and for the treatment of Wilson’s disease. In this investigation, reaction of HCl with MoS 4 2 - in water was monitored as a function of time. Reaction mixtures of both 1:1 and 2:1 mole ratios of the acid to MoS 4 2 - were examined, as well as MoS 4 2 - reactions in simulated human stomach fluids at pH of ∼2 and 3. Monitoring by electrospray mass spectrometry (ESMS), Fourier transform infrared (FTIR), and UV–visible spectroscopy clearly has revealed the formation of complex mixtures of polynuclear thiomolybdates (Mo 2–Mo 18). Generally, a two-stage consecutive reaction sequence occurs. A faster stage ( k = 7.0–7.9 × 10 −2 min −1), which seems to extend to trinuclear thiomolybdate species, followed by a slower second stage ( k = 5.4–15.2 × 10 −4 min −1) to higher polynuclear thiomolybdates. Under acidic conditions (e.g. pH ∼ 3) that could also mimic some human stomach fluids, and under anaerobic atmosphere where the generated hydrogen sulfide is prevented from escaping from the reaction vessel, Mo 3 S 9 2 - predominates over an extended reaction period. In similar reactions under aerobic conditions and where the hydrogen sulfide is irretrievably lost from the reaction mixture the binuclear ( Mo 2 O a S 10 - a 2 - ; a = 0 – 3 ) and trinuclear ( Mo 3 O b S 9 - b 2 - ; b = 1 – 3 ) anions predominate.

Kinetic study of chlorine behavior in the waste incineration process

The waste incineration atmosphere was simulated as HCl/H2O/O2/CO2/N2 in order to experimentally study chlorine behavior as temperature ranges from 1173 to 1473K and residence time varies. The results show that Cl radicals, produced by the decomposition of HCl at high temperature, mainly recombine to form Cl2 and HCl at the quenching section. It was found that temperature, residence time, cooling rate and feeding gas composition influence Cl2 concentration. To thoroughly understand this reaction system, a kinetic model was developed and validated against experimental results. The key reactions and main pathway were found out with the use of sensitivity and rate of production analysis (ROP). The reaction HCl+O2→Cl+HO2 was shown to initiate the reaction system, and it was found that a significant amount of Cl2 was simultaneously produced by the following high temperature reaction: Cl+HOCl→Cl2+OH. In the cooling process, the main consumption reactions of Cl radicals were H2O+Cl→HCl+OH, OH+Cl→HCl+O and Cl+Cl+M→Cl2+M. Among these, the first two reactions can be used to explain the effect of H2O on the concentration of Cl radical at high temperature. In addition, the influence of the quenching rate on the distribution of chlorine was found to occur because of the varying effects that temperature change causes to the different Cl radical consumption reactions.

Stripping of Au(I) from a Loaded Cetyltrimethylammonium Bromide/Tributyl Phosphate Organic Solution: Conversion and Reduction

The recovery of Au(I) from cyanide leaching solutions by solvent extraction techniques has attracted wide interest in the past decades. However, no substantial progress in industries has been reported yet, because of the difficulties concerning gold stripping from loaded organic phases, such as the quaternary amines extraction systems. In this work, a new technique for the recovery of Au(CN)2 − from the loaded cetyltrimethylammonium bromide / tributyl phosphate organic solution by a two‐step stripping procedure is suggested first by Au(CN)2 − conversion by HCl into corresponding chloride complex ions, and then by chemical reduction of auro‐chloride complex ions in TBP organic phases to give metal gold powder. The influences of HCl concentrations, reaction time, and various reducing agents used on the percent gold conversion and reduction were investigated. About 33% of Au(CN)2 − in the initial TBP organic phase could be precipitated as metal gold powder in the conversion step, while 67% was converted into AuCl2 − or AuCl4 − and held in the organic phase. Subsequently, the loaded organic phase after conversion was contacted with reducing agents such as sodium sulfite, ammonium oxalate, or hydrazine hydrate. Most (>98%) of the auro‐chloride complex ions could be effectively reduced as metal gold. As a result, the total gold recovery from the initial TBP organic phases after the two stripping procedures achieved more than 98%. The 198Au radioactive tracer was employed to determine the concentration and distribution behavior of gold in both organic and aqueous solutions. In addition, the experiment on the reuse of the organic phase after gold stripping showed that there was no obvious loss in percent gold(I) recovery after one cycle of the extraction‐ stripping‐ regeneration process no matter what reducing agent was used.

Quantum Mechanical Calculation of Energy Dependence of OCl/OH Product Branching Ratio and Product Quantum State Distributions for the O(1D) + HCl Reaction on All Three Contributing Electronic State Potential Energy Surfaces

OCl/OH product branching ratios are calculated as a function of total energy for the O( (1) D) + HCl reaction using quantum wavepacket methods. The calculations take account of reaction on all the three electronic state potential energy surfaces which correlate with both reactants and products. Our results show that reaction on the excited electronic state surfaces has a large effect on the branching ratio at higher energies and that these surfaces must therefore be fully taken into account. The calculations use the potential energy surfaces of Nanbu and co-workers. Product vibrational and rotational quantum state distributions are also calculated as a function of energy for both product channels. Inclusion of the excited electronic state potential energy surfaces improves the agreement of the predicted product vibrational quantum state distributions with experiment for the OH product channel. For OCl agreement between theory and experiment is retained for the vibrational quantum state distributions when the excited electronic state potential energy surfaces are included in the analysis. For the rotational state distributions good agreement between theory and experiment is maintained for energies at which experimental results are available. At higher energies, above 0.7 eV of total energy, the OCl rotational state distributions predicted using all three electronic state potential energy surfaces shift to markedly smaller rotational quantum numbers.

Adiabatic and nonadiabatic dynamics in the CH3(CD3)+HCl reaction

The scattering dynamics leading to the formation of Cl (2P(3/2)) and Cl* (2P(1/2)) products of the CH(3)+HCl reaction (at a mean collision energy <E(coll)>=22.3 kcal mol(-1)) and the Cl (2P(3/2)) products of the CD(3)+HCl reaction (at <E(coll)>=19.4 kcal mol(-1)) have been investigated by using photodissociation of CH(3)I and CD(3)I as sources of translationally hot methyl radicals and velocity map imaging of the Cl atom products. Image analysis with a Legendre moment fitting procedure demonstrates that, in all three reactions, the Cl/Cl* products are mostly forward scattered with respect to the HCl in the center-of-mass (c.m.) frame but with a backward scattered component. The distributions of the fraction of the available energy released as translation peak at f(t)=0.31-0.33 for all the reactions, with average values that lie in the range <f(t)>=0.42-0.47. The detailed analysis indicates the importance of collision energy in facilitating the nonadiabatic transitions that lead to Cl* production. The similarities between the c.m.-frame scattering and kinetic energy release distributions for Cl and Cl* channels suggest that the nonadiabatic transitions to a low-lying excited potential energy surface (PES) correlating to Cl* products occur after passage through the transition state region on the ground-state PES. Branching fractions for Cl* are determined to be 0.14+/-0.02 for the CH(3)+HCl reaction and 0.20+/-0.03 for the CD(3)+HCl reaction. The difference cannot be accounted for by changes in collision energy, mass effects, or vibrational excitation of the photolytically generated methyl radical reagents and instead suggests that the low-frequency bending modes of the CD(3)H or CH(4) coproduct are important mediators of the nonadiabatic couplings occurring in this reaction system.

Ionization-recombination equilibrium in cold cluster plasma under conditions of retardation by high energy barrier

The kinetics of charge separation in a cold plasma was studied with the degradation reaction in molecular clusters HCl(H2O)n + m(H2O) ↔ H3O+(H2O)n + m −1Cl−, taken as an example, which precedes chlorine adsorption on the ice surface in the stratosphere. The formation of a vast population of H+, Cl− ion pairs stabilized in water clusters ensures the intense binding of chlorine in ice microcrystals that occur in stratospheric clouds. The accumulation of chlorine in the stratosphere is recognized as the main cause of the destruction of the protective ozone layer. The ion buildup effect is a result of the balance between opposite ionization and recombination processes in the presence of a high energy barrier that retards ion recombination in water clusters. A kinetic equation for the process was obtained and its solution was analyzed. The parameters of the barrier were calculated by computer simulation.

Trans-dichlorodioxobis(triphenylphosphate)molybdenum(VI), MoO2Cl2[OP(OPh)3

The molecular structure of trans-dichlorodioxobis(triphenylphosphate) molybdenum(VI), MoO2Cl2[OP(OPh)3]2 has been determined. Crystal data: Monoclinic, Pn, a = 11.767(2), b = 10.341(2), c = 15.682(3) A, β = 92.27(3)°, V = 1906.8(7) A−3, Z = 2. Trans-dichlorodioxobis(triphenylphosphate)molybdenum(VI) was obtained by the reaction of molybdenum oxide, HCl and triphenylphosphate and was characterized by elemental analysis, IR, and 1H-NMR spectroscopy. Trans-dichlorodioxobis(triphenylphosphate)molybdenum(VI), MoO2Cl2[OP(OPh)3]2 V. Huch1, R. Kumar2, S. Mathur1, R. Ratnani2 The immediate environment around Mo is distorted octahedral with two cis-oxygen atoms and two trans-chlorine atoms along with two triphenylphosphate moieties.

Mechanisms involved in chemical vapor generation by aqueous tetrahydroborate(III) derivatization: Role of hexacyanoferrate(III) in plumbane generation

The role played by K 3Fe(CN) 6 (0.08 or 1.5 g l − 1 ) in producing strong enhancement factors in the generation efficiency of plumbane in the reaction of NaBH 4 (10 or 40 g l − 1 ) with Pb(II) (50 μg l − 1 ) in 0.1 M HCl solution, was investigated by using continuous flow chemical vapor generation coupled with atomic fluorescence spectrometry (CF-CVG-AFS). Different mixing sequences and reaction times of reagents were tested using different chemifold setups. Part of CF-CVG-AFS experiments were performed using the on-line, delayed addition of Pb(II) to a K 3Fe(CN) 6 + NaBH 4 reaction mixture. Kinetic calculations estimating the concentration of K 3Fe(CN) 6 remaining in the K 3Fe(CN) 6 + NaBH 4 reaction mixture before it merged with Pb(II) solution were also performed. Batch experiments measuring the amount of hydrogen evolved (pressure of H 2 vs time) and pH variation during K 3Fe(CN) 6 + NaBH 4 + HCl reaction were performed in order to have a correct estimation of the concentration of K 3Fe(CN) 6 remaining in the reaction system. The comparison of CF-CVG-AFS experiments with kinetic calculations indicates that strong enhancement factors of plumbane generation can be obtained without any interaction of K 3Fe(CN) 6 with Pb(II). The key role of K 3Fe(CN) 6 is recognized in its reaction with NaBH 4 to give “special” borane complex intermediates, which are highly effective in the generation of plumbane from Pb(II).

Electrospinning method for the preparation of silver chloride nanoparticles in PVP nanofiber

It has been successfully developed by the electrospinning technology that AgCl nanoparticles were incorporated into polymer fiber. In this paper, we chose poly(vinyl pyrrolidone) (PVP) because it was not only a good material for electrospinning but also it was excellent capping reagent of various metal nanoparticles. The silver ions interacted with the carbonyl groups in the PVP molecules. The formation of AgCl nanoparticles inside the PVP were carried out via the reaction of silver ions and HCl. TEM proved that most of the AgCl nanoparticles were uniformly dispersed in the PVP fibers.

Quantum dynamical study of the O(D1)+HCl reaction employing three electronic state potential energy surfaces

Quantum dynamical calculations are reported for the title reaction, for both product arrangement channels and using potential energy surfaces corresponding to the three electronic states, 1 1A', 2 1A', and 1 1A", which correlate with both reactants and products. The calculations have been performed for J=0 using the time-dependent real wavepacket approach by Gray and Balint-Kurti [J. Chem. Phys. 108, 950 (1998)]. Reaction probabilities for both product arrangement channels on all three potential energy surfaces are presented for total energies between 0.1 and 1.1 eV. Product vibrational state distributions at two total energies, 0.522 and 0.722 eV, are also presented for both channels and all three electronic states. Product rotational quantum state distributions are presented for both product arrangement channels and all three electronic states for the first six product vibrational states.

Heterogeneous Mercury Reaction on a Selective Catalytic Reduction (SCR) Catalyst

The heterogeneous mercury reaction mechanism, reactions among elemental mercury (Hg0) and simulated flue gas across laboratory-scale selective catalytic reduction (SCR) reactor system was studied. The surface of SCR catalysts used in this study was analyzed to verify the proposed reaction pathways using transmission electron microscopy with energy dispersive X-ray analyses (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The Langmuir–Hinshelwood mechanism was proven to be most suitable explaining first-layer reaction of Hg0 and HCl on the SCR catalyst. Once the first layer is formed, successive layers of oxidized mercury (HgCl2) are formed, making a multi-layer structure.

An NMR study of the species produced by the reactions of dialkyl magnesium and HCl with calcined silica and the polymerisation performance of Ziegler–Natta catalysts produced from this support material

The effect of calcinations on the silica surface groups and thereby on the activity of Ziegler–Natta catalysts in ethylene homopolymerisation has been studied. Silica was calcined at different temperatures and treated with MgR 2 and HCl. Silica surface groups were identified by using 1H MAS NMR and 13C and 29Si CP MAS NMR techniques. Magnesium, titanium and chlorine were measured by elemental analysis. Ziegler–Natta catalysts were prepared from these supports and subsequently used in ethylene homopolymerisation. Maximum activity was obtained with the catalyst based on 590 °C calcined silica. The results indicate that MgR 2 reacts with siloxane-groups (Si–O–Si) in the 300 °C calcined silica, leaving the hydrogen-bonded hydroxyl-groups unreacted. Low activity Si–O–Ti(Cl) 2–O–Si species are formed after reacting with TiCl 4. The higher activity in the catalyst based on 590 °C calcined silica can be explained by the formation of –Si(R)–O–Si–O–TiCl 3 groups, originating from the siloxane bridges which cannot form in 300 °C calcined silica. Other explanations for the higher activity are a higher Mg/Ti ratio or small amounts of crystal water formed in the 590 °C calcined silica.

Effects of surface trapped excess electrons on the dynamics of HCl adsorbed ice surfaces

We report results of Car–Parrinello molecular dynamics simulations showing the effect of surface trapped electrons on the dynamics of HCl adsorbed ice surfaces. It is found that the existence of excess electrons can lead to extensive changes in structural and electronic properties of ice surfaces, which provide better environments for proton transfer. The results of simulations show rapid exchanging mechanism of the proton under such environment, suggesting the importance of interlayer proton transfer in the heterogeneous reaction of HCl adsorbed ice surfaces.

Crystal growth of GaN on (0 0 0 1) face by HVPE-atomistic scale simulation

Crystal growth of GaN by hydrogen vapor phase epitaxy (HVPE) is still far from being described on the atomic level. The method consists of reaction of HCl with liquid Ga, transport of gallium by volatile compounds GaCl or GaCl 3, and the deposition on the substrate by the simultaneous reaction of GaCl/GaCl 3 and ammonia (NH 3) on the GaN surface. Various aspects of the method have to be modeled using different approaches. Recently, we have modeled reaction of HCl with gallium and the transport of the resulting species by convection and diffusion using CFD modeling of transport. Surface reaction rate was estimated using atomic flux and sticking coefficient. It has been found that the reaction is controlled by transport or surface reaction depending on the flow velocity and the HCl sticking coefficient [P. Kempisty, I. Grzegory, M. Boćkowski, S. Krukowski, B. Łucznik, B. Pastuszka, S. Porowski, Phys. Stat. Sol. (a) 203 (2006) 131; P. Kempisty, I. Grzegory, M. Boćkowski, S Krukowski, B. Łucznik, B. Pastuszka, S. Porowski, J. Crystal Growth 296 (2006) 31]. The growth of GaN was modeled using atomistic scale simulations. The simulations were carried out using the QM DFT SIESTA code [J.M. Soler, E. Artacho, J.D. Gale, Alberto García, J. Junquera, P. Ordejón, D. Sánchez-Portal, J. Phys.: Condens. Matter 14 (2002) 2745; P. Ordejón, D.A. Drabold, M.P. Grumbach, R.M. Martin, Phys. Rev. B 48 (1993) 14646; P. Ordejón, D.A. Drabold, M.P. Grumbach, R.M. Martin, Phys. Rev. B 51 (1995) 1456]. The model is applied to a 2-d supercell, which corresponds to 2-d periodic boundary conditions suitable for simulation of the surface. Five atomic slabs were used in the direction perpendicular to the surface. The simulations include the analysis of the influence of hydrogen, ammonia and HCl on the atomic structure of the (0 0 0 1) GaN surface (Ga-face). Subsequently, the process of adsorption of various species, such as NH 3, GaCl and H 2 of the GaN(0 0 0 1) surface, was considered. The energy barriers and the stable configurations were obtained. From this, the energetic properties of elementary kinetic processes were obtained. These results were used for the assessment of the influence of the growth conditions on the growth rate of gallium nitride.