Vanadium phosphorus oxide (VPO) catalysts were developed for the aldol condensation of methyl acetate (MeOAC) with formaldehyde (HCHO) to methyl acrylate (MA). The influence of P/V ratio on catalytic activity and selectivity was revealed and optimized with a fixed bed reactor. The controllable preparation of VPO catalyst was reached, and the influence of carrier gas on the resistance of carbon deposition was also systematically investigated. Response surface methodology (RSM) with three independent variables of molar ratio of MeOAC to HCHO, space velocity, and reaction temperature was employed to optimize MA yield with VPO catalysts. The high value of “R-squared” presented a reasonable correlation of regression model to the experimental data. Lastly, the kinetics of aldol condensation to produce MA over VPO catalyst was studied.

A fluidized bed process for the one-step synthesis of methyl acrylate (MA) using methyl acetate (Ma) and formaldehyde (FA) was developed for the first time. New spherical antiwear acid–base catalysts Cs–P/γ-Al2O3 were prepared using ultrasonic impregnation method and characterized with XRD, BET, SEM, PSD, ICP, TG/DTA, NH3-TPD, and CO2-TPD methods. Catalytic performance was evaluated, and 10.0 wt % Cs–5.0 wt % P/γ-Al2O3 with weak acid–base sites was determined to be the best catalyst for MA production. Response surface methodology (RSM) was employed to optimize aldol condensation of Ma with FA over 10.0 wt % Cs–5.0 wt % P/γ-Al2O3. The effects of various process parameters such as reaction temperature, molar ratio of Ma and FA, and liquid hourly space velocity (LHSV) on MA yield were addressed by Box–Behnken experimental design (BBD). The coefficient of determination (R2) of this model was 0.997, and 39.5 mol % yield of MA was obtained after optimization. The developed catalyst exhibited high stability, with no significant decrease in catalytic activity after 1000 h of lifetime evaluation.

•A new route for one-step synthesis of MA at mild temperature was developed.•Soft enolization of ester and depolymerization of trioxane was realized.•The reaction mechanism was proposed and analyzed.•The kinetic and thermodynamic studies were firstly investigated systematically.One-step aldol condensation of methyl acetate with formaldehyde (or trioxane) for preparing methyl acrylate at 623 K–653 K has stimulated researchers’ attention in recent years. Herein, a new methodology for one-step synthesis of methyl acrylate from methyl acetate and trioxane promoted by generated trifluoromethanesulfonate ionic liquid, via aldol condensation, at mild temperature was developed. The kinetic and thermodynamic studies on this new process were also firstly investigated systematically. Experiments were conducted in a batch reactor under the temperatures of 283 K–298 K and reaction times of 10 min–100 min, wherein the side reactions could be ignored. The proposed mechanism-based kinetic model was established and simulated with experimental data. The model showed good agreement with experimental results within the range of acceptable deviation, thereby the pre-exponential factor and activation energy of each reaction step were obtained. Moreover, the equilibrium constant and enthalpy change of each reversible reaction were also calculated through Van’t Hoff formula.

•One-step synthesis of acrylates at room temperature was firstly developed.•The in-situ catalytic strategy was firstly designed and confirmed.•Ester enolization and trioxane decomposition were firstly realized simultaneously.•Relative high yield and selectivity of acrylates were obtained.One-step synthesis of acrylates from acetates and trioxane via aldol reaction at 623 K–653 K was reported. But proceeding this process at room temperature is still a challenge due to ester activation and trioxane decomposition. Herein, series of acrylates were firstly achieved, with the one-step and in-situ catalytic strategy, from acetates (or propionates) and trioxane at 293 K. Selectivity of product reaches up to 94.4% with a 80.8% yield. 1H NMR confirmed the soft enolization of ester, the decomposition of trioxane was catalyzed by TMSOTf, and the generated ionic liquid has catalytic performance on aldol condensation step.Download high-res image (213KB)Download full-size image

A one-pot synthesis of α,β-unsaturated esters from unactivated esters and aldehydes using strong bases, such as sodium alkoxide and potassium tert-butoxide, was reported. However, the ionic liquid (IL) catalyzed probase method for producing α,β-unsaturated esters was not reported until now. In this work, a series of ILs with fluoride anions were firstly prepared and used as catalysts in combination with the probase N,O-bis(trimethylsilyl) acetamide (BSA) for the α,β-unsaturated esters synthesis. This process could also be promoted through the introduction of another IL with Lewis acid sites. The yield and selectivity of the product could reach up to 84.2% and 95.0%, respectively, when [Bmim]F was used in combination with [Bmim]Cl/AlCl3 (the molar fraction of AlCl3 is 0.67). The mechanism investigation through GC-MS indicates that BSA would convert into onium amide, which acted as a strong base for α-H abstraction, with the catalysis of [Bmim]F. Meanwhile, [Bmim]Cl/AlCl3 played an important role in the condensation step between enolates and aldehydes. On the basis of mechanism insights, kinetic and thermodynamic studies were also carried out for a better understanding of this new route.

A series of SiO2-confined Ru3(CO)12 catalysts for the water–gas shift (WGS) reaction was synthesized using a sol–gel method with five different 1-butyl-2,3-dimethylimidazolium ionic liquids (ILs) with BF4−, NO3−, Cl−, OTf−, and NTf2−. FT-IR, XRD, BET, SEM/EDS, TEM, ICP, CO-TPD and TGA were used to determine the influence of the different IL structures and loadings (10–40%) on the structure of the synthesized silica gel, Ru dispersion, and WGS catalytic activity. The results revealed that hydrogen bond formation capability and size of the anion of ILs have significant and sensitive effects. Catalytic activity was tested at atmospheric pressure and low reaction temperatures ranging from 120 to 200 °C. The highest CO conversion of 93.7% was achieved at 160 °C, which showed an around 100 °C decrease compared to traditional catalysts.

Phenolic compounds could be separated through their formation of deep eutectic solvent (DES). This process was different from normal liquid–liquid extraction and was more efficient and environmental. In this work, the thermodynamic process of this kind of separation was studied. Ternary liquid–liquid equilibrium data were systematically measured at atmospheric pressure and temperatures from 303.15 to 313.15 K. The experimental data were regressed by NRTL and UNIQUAC models, and the validated results revealed that NRTL model were more consistent with experimental data. The above-mentioned parameters could be used to predict ternary mixture interactions and then applied in subsequent design and optimization of the separation process of corresponding systems. This extraction process was further optimized using Aspen Plus with NRTL as thermodynamic model. The simulation results were in good agreement with the experimental outcomes.

Reaction distillation was first used for the process of acrylic acid synthesis through transesterification of methyl acrylate with acetic acid using a strongly acidic cationic exchange resin catalyst (NKC-9). Pseudo-homogeneous (P-H) and Langmuir–Hinshelwood (L-H) heterogeneous kinetic models were presented and fitted with the experimental data obtained from the batch reaction. The key factors of the heterogeneous kinetic model were the four components’ adsorption equilibrium constants on the catalyst surface, and they were determined by adsorption experiments. The activity coefficients were calculated using the NRTL method. The catalyst stability was evaluated in a fixed-bed reactor. Catalyst activity showed no obvious decrease after 1000 h of running. A reactive distillation column for acrylic acid synthesis was proposed and designed with process simulation.

Indole is an important industrial substance derived from wash oil, and the traditional alkali fusion method causes serious environmental problems. In this research, imidazolium-based ionic liquids (IBILs) were developed as new extraction agents to separate indole from wash oil with extraction efficiencies of more than 90%. The influence of the IBIL structure was explored. The extraction efficiency and the distribution coefficient of indole were used as the indexes to evaluate the IBIL extraction ability. The key experimental parameters, such as the initial indole concentration, extraction time, extraction temperature, and volume ratio of IBIL-to-model wash oil, were investigated to obtain the optimum conditions. The separation mechanism was studied by analyzing the chemical bonds using spectrographic analysis and molecular simulations. The IBILs were recycled by back-extraction and they exhibited good recycling properties with no obvious reduction and a high extraction efficiency. Finally, the optimal process was conducted based on the process simulation.

Correction for ‘An ionic liquid extraction process for the separation of indole from wash oil’ by Tiantian Jiao, et al., Green Chem., 2015, 17, 3783–3790.

•Acidity is the main factor influencing activity, selectivity, and stability of catalysts.•The diesel produced from palm oil almost conformed to the European standard EN-590.•The oxygen was principally eliminated by hydrodeoxygenation and decarbonylation.Biodiesel, derived from vegetable oil via hydrotreating, is becoming a promising alternative energy. Novel Ni–Mo–W/γ-Al2O3–ZSM-5 catalysts were developed and firstly applied in palm oil hydrogenation process. The catalysts were prepared by extrusion method and characterized by XRD, SEM, TEM, BET, NH3–TPD, and H2–TPR. The influences of acidity on the activity, selectivity, and stability of catalysts were systematically studied. The mechanisms of deoxygenation and isomerization were discussed. The catalyst Ni–Mo–W (5 wt.%–5 wt.%–15 wt.%)/γ-Al2O3–ZSM-5 (85 wt.% − 15 wt.%) was confirmed as the optimum one. Finally, the key reaction parameters such as reaction temperature, pressure, liquid hourly space velocity and H2/oil volume ratio were optimized. The hydrogenation reaction path of palm oil was also proposed.

To obtain clean liquid fuel, a study was conducted on upgrading shale oil by hydroconversion. Various W–Ni catalysts were synthesized and characterized using XRD, BET, TG, H2-TPR, and NH3-TPD methods. The effects of tungsten content and calcination temperature on the physicochemical properties and activity of catalysts were systematically investigated. W–Ni/Al2O3 with 15 wt % W-loading and 550 °C calcination temperature was selected as the optimized catalyst. The product distribution of the primary aromatics in shale oil affected by hydrogenation, ring opening, and cracking reactions was discussed. Finally, key reaction parameters such as pressure, liquid hourly space velocity, and H2/oil volume ratio were optimized. Characteristics of gasoline and diesel fractions were also measured.

The effectiveness of CO2 microsize bubbles for removal of Ca2 + ions in the leaching water discharged from the final landfill site was evaluated using imitation water. For the important parameter in the Ca2 + ion removal, it was found that the treatment in alkaline region above pH = 10 was optimum. The possibility of using CO2 microbubbles was examined by substitution of chemical Na2CO3, which is used in large quantities today. In addition, the excellence of CO2 microbubbles was demonstrated by comparing with CO2 millimeter size bubbles.The Ca2 + ions from leaching water form scale in the drainage pipe, causing the blockage of the pipe. Today, the removal of Ca2 + ions is performed before discharge by using a lot of sodium carbonate (Na2CO3). The amount of Na2CO3 consumed in one year is not less than 200 tons for a final landfill site. Therefore, reducing the amount of chemical used is strongly required from the financial side. In this study, it was demonstrated that the CO2 microbubble method is promising as a new Ca2 + removal technology instead of using chemical, Na2CO3.Download full-size image