Acetylene hydrochlorination over supported ionic liquid phase(SILP)gold-based catalyst:Stabilization of cationic Au species via chemical activation of hydrogen chloride and corresponding mechanisms

The activation of HCl by cationic Au in the presence of C2H2 is important for the construction of active Au sites and in acetylene hydrochlorination.Here,we report a strategy for activating HCl by the Au-based supported ionic liquid phase(Au–SILP)technology with the[N(CN)2^–]anion.This strategy enables HCl to accept electrons from[N(CN)2^–]anions in Au–[N(CN)2^–]complexes rather than from pure[Bmim][N(CN)2],leading to notable improvement in both the reaction path and the stability of the catalyst without changing the reaction triggered by acetylene adsorption.Furthermore,the induction period of the Au–SILP catalyst was shown to be absent in the reaction process due to the high Au(III)content in the Au(Ⅲ)/Au(Ⅰ)site and the high substrate diffusion rate in the ionic liquid layer.This work provides a facile method to improve the stability of Au-based catalysts for acetylene hydrochlorination.

Clean production of chlorine from hydrogen chloride with Mn-compound as intermediate

A new process is developed by using compound Mn as intermediate to produce Cl2from HCl,with the following steps.(1)HCl steam is decomposed by intermediate Mn2O3to produce Cl2and Mn Cl2at 500°C.(2)Produced Mn Cl2is oxidized by water steam to produce Mn O at 450°C.(3)The Mn O compound is oxidized by air to yield Mn2O3.The X-ray diffraction(XRD)crystallite characterization results indicate the high conversion in each step under the optimum experimental conditions.Long term experiments for continuous conversion of HCl to Cl2by using Mn2O3as intermediate in a fixed bed reactor indicate that over 90%of HCl could be converted to Cl2on stream of 30 h.The production of Cl2from HCl with Mn compound as an intermediate and atmospheric steam is a feasible and recyclable process.

Extraction of hydrogen chloride by a coupled reaction-solvent extraction process

A coupled reaction-solvent extraction process was used to remove HC1 from a simulated distiller waste. The extraction performances of various extractants and diluents were compared and the apparent basicity ofN235 （a mixture of tertiary amines） in various diluents was determined. The best results were obtained using N235 and isoamyl alcohol as the extractant and diluent, respectively. The yield of HC1 from the coupled extraction was 75% with this extraction system. The mechanisms for the removal of HC1 in both the direct and coupled extractions were investigated. For the coupled extraction, the formation of an RaNHC1 ion-pair complex was involved in the HC1 removal. For the direct extraction, the mechanism involved the formation of hydrogen bonds at high concentrations of HC1.

Microstructure evolution and corrosion behavior of Fe-Al-based intermetallic aluminide coatings under acidic condition

Two Fe-Al-based intermetallic aluminide coatings were fabricated on 430-SS(Fe-Cr)and 304-SS(Fe-Cr-Ni)substrates by pressure-assisted solid diffusion bonding with coating on pure Fe as control.The microstructure and intermetallic phases of the coatings were characterized by SEM,EDS and EBSD.A network of Cr2Al13 with matrix of Fe4Al13 was formed by inter-diffusing of Al with the substrates.The corrosion behavior of intermetallic coatings was investigated in 0.5 mol/L HCl solution by mass-loss,OCP,Tafel plot and EIS.It was found that corrosion resistance was greatly enhanced by dozens of times after the addition of Cr and Ni compared with that on pure Fe.The presence of cracks in the coating on 430-SS provided a pathway for corrosion media to penetrate to the substrate and accelerated the corrosion rate.Moreover,the corrosion product was analyzed by XRD,demonstrating that the addition of Cr and Ni facilitated the formation of more corrosion resistant phases,and therefore improved corrosion resistance.

Closed Loop Recycling of Chlorine for Sustainable Development of Polyurethane Industry

Increasing demand is fueling the booming polyurethane industry worldwide. An impeding issue for poly- urethane industry is how to handle the large quantity of hydrogen chloride byproduct generated from the synthesis of intermediates, i.e., isocyanates. In the meantime, the traditional chloro-alkaline process sufibrs both from the high en- ergy intensity of electrolysis method and the disparity in the chlorine and caustic soda market. To solve these prob- lems, the state-of-the-art chlorine recycling technologies are reviewed and compared. Approaches for cost-effective utilization of chlorine in polyurethane industry are investigated. Chinese academies and enterprises＇ on-going effort on the development of a novel hydrogen chloride oxidation process for the synthesis of chlorine is presented. With this process, the closed loop recycling of chlorine can be realized. Tremendous economic, environmental and social bene- fits can be expected. A wide adoption of this technology will significantly advance the sustainable development of polyurethane industry.

CI Depletion in the 2006 Antarctic Stratosphere

An examination of the seasonal and spatial distribution of PSCs （polar stratospheric clouds） inferred from standard temperature profiles in the lower-middle atmosphere above Antarctica, as derived from the EOS （earth observing system） Aura MLS （microwave limb sounder） satellite observations and NCEP/NCAR （National Centers for Environmental Prediction/National Center for Atmospheric Research） assimilations, is provided. Chemical VMR （volume mixing ratio） observations of EOS Aura MLS v2.2 HCI （hydrogen chloride） were used to show the interannual variability of PSC formation with respect to stratospheric chlorine partitioning in 2006. A remarkable first set of results, obtained from an algorithm developed for modelling HCI depletion areas in the Antarctic polar vortex region, and based on satellite observations, is presented. In particular, the analysis of HCI concentration data obtained from 2006 indicated that the area processed for HCI was larger than the area of PSC during some periods of Antarctic winter, and that this result was robust with respect to the various PSC formation and HC1 depletion thresholds utilized. The results suggest that an underestimation in chlorine activation area can occur when temperature thresholds for PSC formation thresholds are employed.

Mechanism of Hg^0 oxidation in the presence of HCl over a commercial V_2O_5–WO_3/TiO_2 SCR catalyst

Experiments were conducted in a fixed-bed reactor containing a commercial V2O5/WO3/TiO2 catalyst to investigate mercury oxidation in the presence of HCl and O2. Mercury oxidation was improved significantly in the presence of HCl and O2, and the Hg^0 oxidation efficiencies decreased slowly as the temperature increased from 200 to 400℃. Upon pretreatment with HCl and O2 at 350℃, the catalyst demonstrated higher catalytic activity for Hg^0 oxidation. Notably,the effect of pretreatment with HCl alone was not obvious. For the catalyst treated with HCl and O2, better performance was observed with lower reaction temperatures. The results showed that both HCl and Hg^0 were first adsorbed onto the catalyst and then reacted with O2 following its adsorption, which indicates that the oxidation of Hg^0 over the commercial catalyst followed the Langmuir–Hinshelwood mechanism. Several characterization techniques, including Hg^0temperature-programmed desorption（Hg-TPD） and X-ray photoelectron spectroscopy（XPS）, were employed in this work. Hg-TPD profiles showed that weakly adsorbed mercury species were converted to strongly bound species in the presence of HCl and O2. XPS patterns indicated that new chemisorbed oxygen species were formed by the adsorption of HCl, which consequently facilitated the oxidation of mercury.

Alkylation of benzene with propylene catalyzed by FeCl_(3)-chloropyridine ionic liquid

Alkylation of benzene with propylene was carried out with FeCl_(3)-chloro-butyl-pyridine(FeCl_(3)-[bpc])ionic liquid as catalyst to obtain cumene.Significant improvements in propylene conversion and cumene selectivity under mild reaction conditions were attained by modification of the catalyst with HCl.Under 20℃,0.1 MPa,reaction time 5 min,mole ratio of benzene to propylene 10:1 and mass ratio of FeCl_(3)-[bpc]to benzene 1:100,conversion of propylene can increase from 83.60%to 100.00%and selectivity of cumene can increase from 90.86%to 98.47%.If reaction is carried out in following two stages,the result will be very good.At the initial stage of the reaction,alkylation is the main reaction and a higher conversion of propylene is obtained at a lower tem-perature.At the later stage of the reaction,transalkylation is the main reaction and selectivity to cumene can be increased by appropriately raising the reaction temperature.

Exact quantum and TST-CEQ study of the collinear reaction O+HCl

Exact quantum calculations of reaction probabilities have been carried out using hyperspherical coordinates for the collinear reaction O+HCl(upsilon less than or equal to 1)-->OH(upsilon' less than or equal to 1)+Cl. A generalized LEPS potential energy surface with a barrier height of 8.12 kcal/mol has been used in the calculations. According to the calculated results we found that (1) the reaction probability oscillates with energy, (2) the reaction probability shows vibrational adiabaticity, although it is poorer than that for symmetric reaction Cl+HCl. The analysis of resonance has also been done. The reaction rate constants and average cross sections have been calculated by TST-CEQ method. The rate constants are in agreement with that by QCT and smaller than the experimental one. Finally, the threshold has been estimated and is in good agreement with that of the literature.