HCl Reaction Research Articles

New Stress Test for Ring Polymer Molecular Dynamics: Rate Coefficients of the O(3P) + HCl Reaction and Comparison with Quantum Mechanical and Quasiclassical Trajectory Results.

In the past decade, ring polymer molecular dynamics (RPMD) has emerged as a very efficient method to determine thermal rate coefficients for a great variety of chemical reactions. This work presents the application of this methodology to study the O(3P) + HCl reaction, which constitutes a stringent test for any dynamical calculation due to rich resonant structure and other dynamical features. The rate coefficients, calculated on the 3A' and 3A″ potential energy surfaces (PESs) by Ramachandran and Peterson [ J. Chem. Phys. 2003 , 119 , 9590 ], using RPMD and quasiclassical trajectories (QCT) are compared with the existing experimental and the quantum mechanical (QM) results by Xie et al. [ J. Chem. Phys. 2005 122 , 014301 ]. The agreement is very good at T > 600 K, although RPMD underestimates rate coefficients by a factor between 4 and 2 in the 200-500 K interval. The origin of these discrepancies lies in the large contribution from tunneling on the 3A″ PES, which is enhanced by resonances due to quasibound states in the van der Waals wells. Although tunneling is fairly well accounted for by RPMD even below the crossover temperature, the effect of resonances, a long-time effect, is not included in the methodology. At the highest temperatures studied in this work, 2000-3300 K, the RPMD rate coefficients are somewhat larger than the QM ones, but this is shown to be due to limitations in the QM calculations and the RPMD are believed to be more reliable.

Co-utilization of converter sludge-containing dedust wastewater in iron ore sintering to save fresh water, enhance quality and reduce pollution

Due to the high proportion of the steel output produced by oxygen converter, significant quantities of converter sludge (CS) and dedust wastewater (DW) are generated annually as waste materials. This study tries to achieve the co-utilization of converter sludge-containing dedust wastewater (CSDW) in iron ore sintering to save fresh water and emission reduction. Firstly, this study quantitatively characterized the mineralogical characteristics of the CS through X-ray diffraction (XRD-Rietveld) and scanning electron microscope (SEM-EDS). The results indicated that the iron oxides wrapped the metallic Fe, and other impurities such as CaO, MgO and ZnFe2O4 mixed in the way of physical accumulation. The mineral composition of CS was metallic iron (9.2%), wustite (47.5%), calcium carbonate (31.7%), magnesium ferrite (4.8%), and zinc ferrite (6.7%). Influence of CSDW concentration on the granulation performance and sintering indexes was systematically studied through a series of experiments. Research findings showed that the permeability firstly raised from 9.66 to 12.88 JPU and then reduced to 11.94 JPU, and reached the maximum when the CSDW concentration was 40%. Migration behaviors of harmful elements Zn, K, Na, and Cl have been studied based on experiments and thermodynamic calculations. Cl in DW plays an important role in promoting the removal of alkali metals. The catalytic mechanism can be summarized as the reaction of HCl, Cl2 and alkali metal oxides (Na2CO3, K2CO2, NaAlSi2O2, and KAlSi2O2) to form NaCl and KCl. With this technology, the removal rate of ZnO, K2O, and Na2O increased from 23% to 74%, 13%–42%, 1%–34%, respectively. This study aims to propose a new method for the co-utilization of CSDW in iron ore sintering, which would be helpful to save fresh water and reducing emissions in the iron and steel industry.

Investigation of adsorption characteristics of four toxic gases (nitric oxide, nitrogen dioxide, sulfur dioxide, and hydrogen chloride) on the inner surface of nickel-coated manganese steel cylinders and aluminum cylinders

ABSTRACT To develop standard toxic gas mixtures, it is essential to identify adsorption characteristics of each toxic gas on the inner surface of a gas cylinder. Thus, this study quantified adsorbed amounts of the four toxic gases (nitric oxide [NO], nitrogen dioxide [NO2], sulfur dioxide [SO2], and hydrogen chloride [HCl]) on the inner surface of aluminum cylinders and nickel-coated manganese steel cylinders. After eluting adsorbed gases on the inside of cylinders with ultrapure water, a quantitative analysis was performed on an ion chromatograph. To evaluate the reaction characteristics of the toxic gases with cylinder materials, quantitative analyses of nickel (Ni), iron (Fe), and aluminum (Al) were also performed by inductively coupled plasma optical emission spectrometry (ICP-OES). It was found that the amounts of NO, NO2, and SO2 adsorbed on the inner surface of aluminum cylinders were less than 1.0% at the level of 100 μmol/mol mixing ratio, whereas the signal for most heavy metal elements were below their respective detection limits. This study found that the amounts of HCl adsorbed on the inner surface of nickel-coated manganese steel cylinders were less than 5% at the level of 100 μmol/mol mixing ratio, whereas Ni (86 μmol) and Fe (28 μmol) were detected in the same cylinders. It was revealed that the adsorption mainly took place via the reaction of HCl with inner surface material of nickel-coated manganese steel cylinders. On the other hand, in the case of aluminum cylinders, the amounts of the adsorption were determined to be less than 1% at the level of HCl 100 μmol/mol mixing ratio, whereas most of Ni, Fe, and Al were detected at levels similar to their limits of detection. As a result, this study found that aluminum cylinders are more suitable for preparing HCl gas mixtures than nickel-coated manganese steel cylinders. Implications: To develop a standard toxic gas mixture, it is essential to understand the adsorption characteristics of each toxic gas inside a gas cylinder. It was found that the amounts of NO, NO2, and SO2 adsorbed inside aluminum cylinders were less than 1.0% at the level of 100 μmol/mol mixing ratio. The amounts of HCl adsorbed inside nickel-coated manganese steel cylinders were less than 5% at the level of 100 μmol/mol mixing ratio, whereas those inside aluminum cylinders were less than 1%, indicating that aluminum cylinders are more suitable for preparing HCl gas mixtures.

Oxychlorination Redispersion of Pt Catalysts: Surface Species and Pt-Support Interactions Characterized by X-ray Absorption and FT-IR Spectroscopy

To help elucidate the oxychlorination redispersion reaction mechanism, the surface species formed on the surface of γ-Al2O3 was characterized by X-ray absorption spectroscopy (XAS). The efficacy of redispersion was assessed by the Pt–Pt coordination number (CNPt–Pt) of redispersed, and then reduced samples. A nearly fully redispersed complex (Ptrd52) was prepared by treating a sintered model Pt/γ-Al2O3 catalyst at 520 °C, Air/EDC (ethylene dichloride) of 30, and WHSV (Weight Hourly Space Velocity) of 0.07 h−1 for 16 h. For investigating temperature effects, samples treated at 460 (Ptrd46) and 560 °C (Ptrd56) were also prepared for comparison. It was found that, while an octahedral resembling Pt(Os)3–4(O–Cl)2–3 (Os represents support oxygen or hydroxyl oxygen) complex was formed on γ-Al2O3 of Ptrd52, less O–Cl ligands were formed on the redispersed complexes, Ptrd46 and Ptrd56. A negative correlation of CNPt–Pt with CNPt–Cl* (Cl* represents the Cl atom in O–Cl ligand) for these three samples further suggested that the formation of Pt–O–Cl played a key role in the redispersion process. Pt–O–Cl could be formed in the reaction of reactive Cl⋅ and PtO2. At an operation temperature of lower-than-optimal temperatures of 520 °C, less Cl2 dissociation and less O–Cl ligands were formed. On the other hand, higher temperatures may facilitate Cl2 dissociation, but reduce the equilibrium conversion of HCl to Cl2, leading to increased HCl reaction with Pt (PtO2) clusters to form Pt–Cl (Cl is the atom bonded directly to Pt), and decreased formation of Pt–O–Cl.

Isotope effect and Coriolis coupling effect for the Li + H(D)Cl LiCl + H(D) reaction**Project supported by the National Natural Science Foundation of China (Grant Nos. 11274096 and 11604083).

A time-dependent quantum wave packet method is used to investigate the dynamics of the Li+ H(D)Cl reaction based on a new potential energy surface (J. Chem. Phys. 146 164305 (2017)). The reaction probabilities of the Coriolis coupled (CC) and centrifugal sudden (CS) calculations, the integral cross sections, the reaction rate constants are obtained. The rate constants of the Li+ HCl reaction are within the error bounds at low temperature. A comparison of the CC and CS results reveals that the Coriolis coupling plays an important role in the Li+ H(D)Cl reaction. The CC cross sections are larger than the CS results within the entire energy range, demonstrating that the Coriolis coupling effect can more effectively promote the Li+ DCl reaction than the Li+ HCl reaction. It is found that the isotope effect has a great influence on the title reaction.

Formation of surface chlorine species by low temperature reaction of HCl with metal-doped carbon

A model carbon prepared from phenolic resin was O2-activated and then impregnated with Ca, Cu or Zn to clarify chlorine behavior in coal utilization. Ease of interaction between HCl and the carbon material was enhanced at 100–300 °C. The concentration at which HCl reacted with Ca, Cu and Zn was high. The surface chloric species that were generated by reaction of the carbon substrate with HCl were studied using X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD). XPS measurements suggested the presence of inorganic chloride and organic chlorine species after reaction with HCl. When the carbon samples were washed after the HCl reaction, most of the HCl was eluted. Chemically adsorbed HCl species were also detected by TPD measurement; the presence of inorganic chloride, organic chlorine and chemically adsorbed HCl species were indicated. No correlation was determined between the amount of organic chlorine species generated and the number of activated carbon sites at 100 °C. However, the amount of organic chlorine at 300 °C indicated a tendency to increase with the number of carbon sites, and the surface functional oxygen groups acted as sites for the generation of C-Cl bonds. As a result, possible scheme for the generation of organic chlorine species at low temperature by reaction between HCl and the metal-doped (Ca, Cu or Zn) carbon is discussed.

Kinetic mechanism of aluminum removal from diamond wire saw powder in HCl solution.

Impurity removal is essential for the recovery and regeneration of silicon resources from diamond wire saw powder by metallurgical purification technologies. In this paper, the aluminum was removed from the diamond wire saw powder via a direct HCl leaching method. In order to analyze the removal efficiency of various experimental conditions, certain parameters such as HCl concentration, leaching temperature, reaction time and liquid-solid ratio were also investigated. Particularly, the removal efficiency of Al reached 95.6% under the optimal leaching condition, such as the HCl concentration of 4 mol·L-1, the leaching temperature of 60 °C, the reaction time of 3 h, and the liquid-solid ratio of 10. The shrinking core model and homogeneous model were then respectively utilized to describe the leaching kinetics of the Al removal leaching process. The results indicated that the homogeneous model was more suitable than the shrinking core model. Moreover, the kinetics parameters regarding the reaction orders m=3, n=2.81, the activation energy Ea=97.30kJmol-1, the frequency factor A=1.11×1014 min-1. Furthermore, the leaching mechanism of Al removal was revealed based on kinetic analysis and materials characterization. This work is of great practical value in terms of regenerating silicon resources from the diamond wire saw powder waste materials with efficient and low cost methods.

Matrix Infrared Spectra, Photochemistry and Density Functional Calculations of Cl--HCCl2, ClHCl-, Cl-ClCCl, and Cl--HCHCl Produced from CHCl3 and CH2Cl2 Exposed to Irradiation from Laser Ablation.

Strong absorptions for Cl--HCCl2 with D and 13C isotopes were observed in the spectra of CHCl3 codeposited with laser-ablated metal atoms, cations, electrons, and vacuum ultraviolet radiation, which shows that the precursor is an effective electron scavenger. The IR spectra, isotopic shifts, and DFT calculations identified the major product as Cl--HCCl2, which is characterized by a strong, broad C-H stretching mode interacting with the overtone of the H-C-Cl bending fundamental. These absorptions decreased on subsequent annealing and photolysis treatments while the ClHCl- absorptions increased, suggesting that dissociation of the chloroform anion generates the stable symmetrical hydrogen dichloride anion as does the reaction of HCl and Cl-. A new set of strong, broad absorptions in the deposition spectra that diminished on the early annealing and photolysis are assigned to the Cl-ClCCl radical isomer. Dominant spectral features in the C-H stretching region for the experiments with CH2Cl2 are assigned to the symmetric C-H and the antisymmetric Cl-H-C-H stretching bands of the methylene chloride anion Cl--HCHCl. The stronger, broader, lower frequency bands are due to the hydrogen-bonded hydrogen stretching, and the weaker, sharper, higher frequency absorptions are due to the terminal C-H bond stretching. Similar experiments with CHBr3 produced absorptions for the analogous Br--HCBr2 and BrHBr- anions.

Molecular adsorption and surface formation reactions of HCl, H2 and chlorosilanes on Si(100)-c(4 × 2) with applications for high purity silicon production

The interaction of chlorosilanes and the silicon surface is an important part of reaction processes, such as hydrochlorination and chemical vapor deposition, involved in the production of high purity silicon. We used plane-wave based density functional theory (DFT) to investigate periodic slabs of the Si(100)-c(4 × 2) surface for adsorption of H2, HCl, SiCl2, dichlorosilane (SiH2Cl2 or DCS), trichlorosilane (SiHCl3 or TCS) and silicon tetrachloride (SiCl4 or STC). The effects of surface coverage, molecule orientation, adsorption site and multiple molecule adsorption were studied. All the molecules could undergo dissociative chemisorption in the right orientation and site placement, with HCl and SiCl2 possessing the strongest binding energies. The H2 molecule preferred lower coverage, the HCl molecule was not much affected by coverage while the SiCl2 molecule strongly preferred higher coverage and the STC molecule was affected negatively by both too high or low coverage. The elementary steps leading to transfer of surface crystal silicon atoms to gas phase molecules as part of the chlorination or hydrochlorination process were then looked at through reaction pathway analysis. The formation of SiCl2 from a surface dimer Si atom was found to prefer an intradimer route with a reaction barrier of 3.62 eV (83.48 kcal/mol), going down to 3.10 eV (71.49 kcal/mol) after removal of the first surface Si atom. The subsequent formation of TCS from this SiCl2 was found to have reaction barrier of 1.07 eV (24.68 kcal/mol). STC could also be formed from this SiCl2 molecule with a reaction barrier of 2.86 eV (65.95 kcal/mol).

Copper and gold recovery from CPU sockets by one-step slurry electrolysis

Recently, the life span of electric and electronic products is becoming shorter and shorter because of the rapid technology innovation and the rising standard of consuming. This also leads to a stable annual increase of waste electric and electronic equipment (WEEE). Waste printed circuit boards, the base of almost all WEEE, are always the core of WEEE recycling. However, few studies are focused on the recovery of WPCBs electronic components. Here, in this study, CPU sockets were chosen as a representative electronic component to explore if slurry electrolysis can directly and simultaneously recycle copper and gold. Four factors, HCl concentration, pulp density, current density and reaction time, were discussed in detail. The results show that copper recovery rate first increases and decreases with the rise of HCl concentration, pulp density and reaction time, and it increases with the increase current density. Copper recovery rate and purity is up to 96.67% and 98.16% respectively at the optimum conditions (4 mol/L HCl, 75 g/L pulp density, 80 mA/cm2 and 4 h). One third of copper can be electrodeposited to the cathode plate, and be collected directly. 67% copper still exit in the electrolyte, which needs to be further recycled, and less than 1% copper are in the anode residue. Gold recovery rate first increases and then decreases with the rise of the four factors, reaching to the highest value of 95.73% (4 mol/L HCl, 100 g/L pulp density, 70 mA/cm2 current density and 4 h). Gold mainly exits in the electrolyte, and little gold can be electrodeposited. Besides, the results of XRD and SEM show that the obtained metal powder is mainly copper and copper powder particles are mainly dendritic. On the basis of these results, slurry electrolysis could be applied to the recovery of copper and gold from electronic component.

Temperature Dependence of the Reaction HCl + OH → Cl + H2O between 140 and 1100 K

Temperature dependence of the molecule‐radical reaction HCl + OH → Cl + H2O at temperatures between 140 and 1100 K is studied using a quasiclassical trajectory method. Potential energy surfaces are formulated using pair‐wise additive two‐body, nonadditive three‐body, and four‐body analytic forms and long‐range interactions. At temperatures above 300 K, the reaction occurs by direct collisions and the calculated rate constant fits the Arrhenius equation kdir = 4.85 × 10−12 exp.(−631 ± 10/T) cm3/molecule/s. At temperatures below 300 K, the reaction is driven by an attractive potential and occurs through the formation of a ClH…OH collision complex, which is sufficiently long‐lived to enhance quantum mechanical tunneling of the H atoms. The sum of the direct and complex‐mode reaction rates effectively describes the reaction occurring at temperatures in the 140–1100 K temperature range.

Geochemical changes in experimental water or HCl reactions of the Cooper Basin REM shales

Production or flow-back water from shale gas stimulation has been reported in the USA to contain high salinity, TDS and variable concentrations of potentially toxic metals such as uranium, barium, or lead. The shales of the Cooper Basin REM sequence have a high prospectively for unconventional gas. Water reactions of shale core samples were performed in mildly oxic conditions and at elevated temperature and pressure to investigate potential for metal mobilisation. A relatively higher concentration of lead, vanadium, chromium, zinc and copper, was measured in the Roseneath shale core, which on water reaction mobilized a higher concentration of dissolved uranium, cadmium, cobalt, chromium, zinc, copper and nickel. Mobilized metal concentrations were however generally <10% of the amount available in the core. Relatively higher concentrations of calcium, magnesium and sodium were mobilized from the Murteree shale. Mobilised uranium and barium however remained low. SEM-EDS indicated that the carbonates were most reactive, with dissolution creating porosity in the Roseneath shale. Fe-rich precipitates were also formed in both cases. We found the presence and type of carbonate and sulphide minerals have a strong control on water chemistry and generated acidity. When reacted with HCl, the Epsilon Formation sample showed strong corrosion of carbonates leaving pits, with no Fe-rich precipitates formed. Experimental fluid-rock interactions can give understanding and insights to the potential chemistry of flow back water which may be different from different shale formations.

Exploration of reaction mechanism between acid gases and elemental mercury on the CeO2–WO3/TiO2 catalyst via in situ DRIFTS

Although the oxidation of elemental mercury (Hg0) on catalyst can be significantly affected by acid gases, its mechanism is still unclear. This study used in situ DRIFT to research the influence of acid gases (NO, HCl and SO2) on the performance of mercury oxidation on catalyst CeO2(5)–WO3(9)/TiO2. The catalyst could capture a large amount of Hg0 on the surface yet not oxidize all Hg0 into gaseous oxidation mercury (Hg2+) due to the limit of oxidation sites (CeO2). The addition of NO and HCl improved the mercury oxidation efficiency because this process transformed the adsorbed mercury on the catalyst into gaseous Hg2+ and formed new active sites. The in situ DRIFTS result indicated that NO2 and nitrate served as active sites for mercury oxidation. The formation of active chlorine (Cl∗) via HCl adsorption on the catalyst promoted the transformation of mercury into gaseous HgCl2. The NO and HCl addition could keep the mercury oxidation efficiency over 91.5% with the presence of 500–3000 ppm SO2 and increase the SO2 resistance of the catalyst. The reaction of NO and Hg0 conforms to the Eley-Ridcal mechanism, while the reaction of HCl and Hg0 follows the Languir-Hinshelwood mechanism.

Dynamics of reactions inhibiting epitaxial growth of Si(100) surfaces via interaction with hydrogen chloride

The dynamics of reactions of HCl at growing Si(100) surfaces was investigated through computational methods, using clusters of different sizes and shapes. The analysis was conducted through Gaussian09 at the B3LYP/6-31G(d,p) level. It was found that adsorption of HCl on H-passivated dimers does not proceed as easily as on non-passivated dimers. In addition, analysis of reactions between HCl and a SiCl2 moiety adsorbed on a surface dimer indicated that HCl can lead to detachment of the SiCl2 moiety from the surface in the form of a SiCl2 or a SiHCl3 molecule, or to diffusion of the moiety to a neighboring dimer. However, when the dimer on which SiCl2 adsorbs had been H-passivated prior to adsorption, the reaction of HCl with the SiCl2 moiety becomes significantly more difficult. H-passivation of surface dimers seems thus to promote surface growth by protecting the surface against HCl adsorption and by preventing detachment or diffusion of the adsorbed SiCl2 moiety, which is pointed out as an important intermediate in the growth mechanism. These results are in consonance with evidence found for the convenience of H-passivation of surface dimers prior to silicon deposition, already published in the literature.

Impact of Post-CCSD(T) Corrections on Reaction Energetics and Rate Constants of the OH• + HCl Reaction.

High level ab initio calculations have been performed to predict the reaction energy and barrier height for the OH• + HCl reaction. After including the effect of full quadratic excitations at the coupled cluster level, in addition to core, relativistic, spin-orbit, and diagonal Born-Oppenheimer corrections, we found the values of reaction energy and barrier height to be -15.29 and +2.38 kcal mol-1, respectively. Employing this reaction energy and barrier height, we used variational transition state theory in conjunction with small curvature tunneling to calculate the rate constants within a temperature range from 138 to 1000 K. The calculated rate constants were found to be in good agreement with available experimental results throughout the whole temperature range.

Seasonal characteristics of chemical compositions and sources identification of PM2.5 in Zhuhai, China.

Fine particulate matter is associated with adverse health effects, but exactly which characteristics of PM2.5 are responsible for this is still widely debated. We evaluated seasonal dynamics of the composition and chemical characteristics of PM2.5 in Zhuhai, China. PM2.5 characteristics at five selected sites within Zhuhai city were analyzed. Sampling began on January 10, 2015, and was conducted for 1year. The ambient mass concentration, carbon content (organic and elemental carbon, OC and EC), level of inorganic ions, and major chemical composition of PM2.5 were also determined. Average concentrations of PM2.5 were lower than the National Ambient Air Quality Standard (NAAQS) 24-h average of 65μg/m3. The daily PM2.5 concentration in Zhuhai city exhibited clear seasonal dynamics, with higher daily PM2.5 concentrations in autumn and winter than in spring and summer. Carbon species (OC and EC) and water-soluble ions were the primary components of the PM2.5 fraction of particles. Apart from OC and EC, chemical species in PM2.5 were mainly composed of NH4+ and SO42-. There was a marked difference between the summer and winter periods: the concentrations of OC and EC in winter were roughly 3.4 and 4.0 times than those in summer, while NH4+, SO42-, NO3-, and Na+ were 3.2, 4.5, 28.0, and 5.7 times higher in winter than those in summer, respectively. The results of chemical analysis were consistent with three sources dominating PM2.5: coal combustion, biomass burning, and vehicle exhaust; road dust and construction; and from reaction of HCl and HNO3 with NH3 to form NH4Cl and NH4NO3. However, additional work is needed to improve the mass balance and to obtain the source profiles necessary to use these data for source apportionment.

Quantifying Disproportionation in Pharmaceutical Formulations with 35Cl Solid-State NMR.

Reliable methods for the characterization of drug substances are critical for evaluating stability and bioavailability, especially in dosage formulations under varying storage conditions and usage. Such methods must also give information on the molecular identities and structures of drug substances and any potential byproducts of the formulation process, as well as providing a means of quantifying the relative amounts of these substances. For example, active pharmaceutical ingredients (APIs) are often formulated as ionic salts to improve the pharmaceutical properties of dosage forms; however, exposure of such formulations to elevated temperature and/or humidity can trigger the conversion of an ionic salt of an API to a neutral form with different properties, through a process known as disproportionation. It is particularly challenging to identify changes of pharmaceutical components in solid dosage formulations, which are complex heterogeneous mixtures of the API and excipient components (e.g., binders, disintegrants, and lubricants). In this study, we illustrate that ultra-wideline (UW) 35Cl solid-state NMR (SSNMR) can be used to characterize the disproportionation reaction of pioglitazone HCl (PiogHCl) in mixtures with metallic stearate excipients. 35Cl SSNMR can quantitatively detect the amount of PiogHCl in mixed samples within ±1 wt % and measure the degree of PiogHCl disproportionation in formulation samples stressed at high relative humidity and temperature. Unlike other methods used for characterizing disproportionation, our experiments directly probe the Cl- anions in both the intact salt and disproportionation products, revealing all of the chlorine-containing products in the solid-state chemical reaction without interfering signals from the formulation excipients.

A novel air-assisted liquid-liquid microextraction based on in-situ phase separation for the HPLC determination of bisphenols migration from disposable lunch boxes to contacting water

In this study, a novel air-assisted liquid-liquid microextraction (AALLME) method was developed for the HPLC determination of bisphenols migration from disposable plastic lunch box to contacting water. The AALLME was carried out in commercially-available medical plastic syringes with low-density extraction solvent (n-octanol), and the reaction of NaHCO3 and HCl was introduced to simultaneously induce the in-situ phase separation and salt effect. After the AALLME processes, the upper organic phase was pushed into the end of syringes (narrow tube) by moving the piston so that it could be readily collected for the HPLC analysis. The factors including the type and volume of extraction solvent, NaHCO3 addition and extraction cycles were optimized. Under the optimal conditions, the limits of detection (LODs) for target bisphenols were evaluated to be 0.2–0.7 μg L−1, and good linearities with correlation coefficients higher than 0.9955 were obtained. The recoveries for target bisphenols ranged from 80% to 106%, with the relative standard deviations (RSDs) of 4.4–14.1%. The proposed method was successfully applied to investigate the migration of bisphenols from the disposable plastic lunch boxes to the contacting water, revealing that compared to the conventional water-bath heating, the microwave heating could induce the significant migration of bisphenols in a much shorter time.

Low-Temperature Reactions of HCl with Metal-Doped Carbon

A model carbon prepared from phenolic resin was activated with O2 and then impregnated with Ca, Cu, or Zn to examine the relationship between the amount of HCl desorbed from carbon samples containing various metals in this lower temperature range (100 and 300 °C) and clarified the effect of active sites on HCl adsorption. The results showed that interactions between HCl and carbon were enhanced at temperatures in the range of 100–300 °C and that the amount of HCl reacted was increased by doping with these metals. The different HCl concentration profiles at 100 and 300 °C were obtained with a greater overall decrease in HCl at the lower temperature (100 °C). Those are attributed to increased physical adsorption of HCl at 100 °C. The mass of HCl reacted increased in the order of Cu < Ca < Zn at 300 °C and Ca < Cu < Zn at 100 °C, and HCl reacted at 300 °C was evidently more stable than that reacted at 100 °C. Organochlorine compounds, chemisorbed HCl, and inorganic chlorides were all identified on the carbon...

Chlorine Production by HCl Oxidation in a Molten Chloride Salt Catalyst

A molten salt mixture containing 45 mol % KCl and 55 mol % CuCl2 was investigated as a catalyst for the reaction of HCl with O2 to produce Cl2. The HCl conversion for an HCl:O2 molar feed ratio of 1:2 at 450 °C and a total pressure of 1 atm was 80% at a residence time of less than 1 s in a lab scale bubble column reactor. The equilibrium conversion at this temperature and pressure is 84%. The catalyst system was found to remain stable throughout a continuous 24-h experiment. The use of a mixed transition metal/alkali metal molten salt catalyst for HCl oxidation reduces the volatility of supported chlorides and may avoid the mechanical stability limitations of solid catalysts caused by volume changes between the halide and the oxide.