The density and viscosity of the cyclopropyl methyl ketone (CPMK) + 2-acetylbutyrolactone (ABL) and CPMK + 5-chloro-2-pentanone (CPE) binary mixtures were measured at the temperature range of 303.15 to 333.15 K at atmospheric pressure (about 101.325 ± 0.3 kPa). The excess molar volume and viscosity deviation were calculated based on the experimental data of density and viscosity, and they could be accurately described by the Redlich–Kister equation. In addition, the vapor–liquid equilibrium (VLE) data for the CPMK-ABL binary system were measured at atmospheric pressure. It was shown that there is no azeotrope in this binary mixture. The VLE data were correlated with NRTL, Wilson, and UNIQUAC models and the interaction parameters obtained were reported. The prediction accuracies of these models were about the same.

This paper aims to present the feasibility of conducting the transesterification of propylene glycol ether (PM) with methyl acetate (MeAc) in a reactive distillation (RD) column to improve the reaction conversion. The essential thermodynamic and reaction kinetic data of the reaction system were measured for the feasibility study. There is only one azeotrope, MeAc–MeOH, in the reaction system, and the NRTL model could describe well the thermodynamic behavior of this system. The transesterification of PM with MeAc is an endothermic reaction with activation energy E = 55.704 kJ·mol–1. The feasibility was analyzed by residue curve maps (RCM), showing that full conversion of PM could be realized by RD with a mole ratio of MeAc–PM larger than 2.882. The intensification effect was experimentally verified in a batch RD column. Finally, some important parameters are given through the conceptual design to develop a continuous RD column for the transesterification of PM with MeAc.

We show the superiority of reactive dividing wall column (RDWC) to the single reactive distillation (RD) column in improving the conversion of reactant, taking the hydrolysis of methyl acetate (MA) as example. It is difficult to achieve above 99% conversion for MA in a traditional reactive distillation column (TRDC) due to the existence of self-catalyzed methanol (MeOH)-acetic acid (HAc) esterification reaction in the column bottom. In this work, more than 99% conversion of MA hydrolysis was realized experimentally in an RDWC by separating MeOH from the hydrolysis mixture. The effects of several operation parameters on hydrolysis conversion were systematically investigated, including feedwater–MA mole ratio, heat duty, mole flow rate of feed MA, and vapor distribution. The simulation results by Aspen Plus showed that RDWC has several improvements in MA hydrolysis over TRDC, including lower energy consumption, lower water–MA mole ratio, and larger production capacity. With the increase in MA conversion, the superiorities became more obvious and contribute to the weaker self-catalyzed MeOH–HAc esterification reaction in the RDWC.

•Density and viscosity of [CyN1,1PrSO3H][Tos] with water and methanol were measured.•The thermal properties of the pure IL, just like lattice energy, were calculated.•The apparent molar properties were correlated by Redlich-Mayer equation.•The viscosity of binary mixtures was satisfactorily correlated by VFT equation.Densities, ρ and viscosities, η of N,N-dimethyl-N-(3-sulfopropyl)cyclohexylammo-nium tosylate ([CyN1,1PrSO3H][Tos]) with water and methanol were measured, at temperatures from 303.15 K to 328.15 K with 5 K interval and 0.1013 MPa, as a function of [CyN1,1PrSO3H][Tos] molality (or mass fraction). The isobaric thermal expansion coefficient, molecular volume, standard molar entropy, and lattice energy of the pure IL were obtained based on the density data of pure IL. The apparent molar volume, Vφ, infinite dilution apparent molar expansibility, Eφ∞ and energy barrier, E were calculated from the experimental data. The Redlich-Mayer equation was used to evaluate infinite dilution apparent molar volume, Vφ∞. In addition, viscosities can be described satisfactorily by Vogel-Fulcher-Tammann (VFT) equation. The Vφ∞ values of the IL in water are higher than those in methanol, which suggests that the ion-solvent interactions for [CyN1,1PrSO3H][Tos] + water binary system are stronger than those for [CyN1,1PrSO3H][Tos] + methanol. And the energy barrier values decrease with the drop of IL mass fraction in both systems, indicating that the viscosity changes of binary mixtures are more sensitive to the temperature at high composition of the IL.

•Two new Brönsted acidic ionic liquids (ILs) were prepared and characterized.•Synthesis of biodiesel from tung oil was proposed with Brønsted acidic ILs as catalyst.•[Ps-N-Ch(Me)2][p-TSA] exhibits better on its catalyst activity.•The maximum biodiesel yield of 98.98% was obtained.•The catalyst has excellent utility for repeated use.Two new Brönsted acidic ionic liquids were prepared and characterized by NMR and FTIR. Their catalytic activities for the synthesis of biodiesel fuel via transesterification of tung oil with methanol were evaluated and compared to that of two imidazole-based ionic liquids for the first time. Among them, [Ps-N-Ch(Me)2][p-TSA] exhibited the highest catalytic activity and was chosen as catalyst for further research. A study on optimizing the reaction conditions was performed by orthogonal experiment based on the single factor experiment. It was found that the ranking of the significance of factors on the biodiesel yield is as follows: molar ratio of methanol to oil > reaction temperature > reaction time > catalyst dosage. The maximum biodiesel yield reaches 98.98% under the optimal reaction conditions at a molar ratio of methanol to oil of 21:1, a reaction temperature of 120 °C, a reaction time of 2 h and a catalyst dosage of 5.0 wt.%. Moreover, the reusability experiment exhibits that the catalyst can be reused five times with negligible loss of the activity. The refined biodiesel meets the biodiesel standard ASTM D6751-07, which can be used as fuel in diesel engines.Download high-res image (133KB)Download full-size image

•The upscaling process of mass transfer and reaction in porous media was carried out.•A typical first-order reversible heterogeneous reaction was considered.•The method of volume averaging was used to derive the macroscopic model.•The influence of reaction rates on the effective parameters was investigated.•A simple and practical empirical approach was proposed.The upscaling process of multicomponent mass transfer and reaction in a rigid and homogeneous porous media was carried out using the method of volume averaging. The first-order reversible reaction which occurs at the solid-fluid interface was considered in this paper. The corresponding macroscopic governing equations were derived from the system dynamics at the pore scale. The effective coefficients were obtained by solving the associated closure problems. This study shows that if the backward reaction rate constant at the microscale is small enough, i.e. k-→0, the obtained upscaled model is in accordance with the macroscopic model derived from the first-order irreversible heterogeneous reaction case which was extensively investigated in the literature. The influence of reaction rates on the effective parameters in the macroscopic equations was also investigated. It has been found that both forward and backward reaction rates have significant influence on the effective diffusivities and effective reaction rates in the macroscopic equations. The established equations were successfully verified by the comparison of the direct numerical calculations.

•A mathematical mixture model of hybrid nanofluids was proposed.•PEC was used to assess heat transfer performance under identical pumping power.•Higher PEC could be achieved by using appropriate hybrid nanofluids.•Heat transfer performance of hybrid nanofluids was optimized by varying NBT.In the study, a mathematical model of hybrid nanofluids was established with the consideration of nanoparticles migration, which has significant influence on the thermophysical properties of hybrid nanofluids. In order to investigate heat transfer and friction factor characteristics of hybrid nanofluids in a channel, the corresponding governing equations were solved by using the Runge-Kutta-Gill method. A Performance Evaluation Criteria (PEC) was used to assess heat transfer performance of hybrid nanofluids under identical pumping power. Two hybrid nanofluids, which are alumina-titania/water nanofluid and alumina-zirconia/water nanofluid, respectively, were discussed. The results clearly indicated that alumina-titania/water nanofluid exhibits higher Nusselt number and lower friction factor than alumina-zirconia/water nanofluid. Moreover, it has been found that with the variation of volume fraction ratio of two single-particle nanofluids, maximum PEC values of alumina-titania/water nanofluid were observed, proving that alumina-titania/water nanofluid has better heat transfer performance than either alumina/water nanofluid or titania/water nanofluid under identical pumping power. The effects of NBT1 variation and NBT2 variation of alumina-titania/water nanofluid on Nusselt number and friction factor were also investigated. It is interesting to note that minimum PEC values were observed under the variation of NBT2 whenNBT1/NBT2 is approximately 6. However, maximum PEC values were observed under the variation of NBT1 when NBT1/NBT2 is approximately 0.5.

•A microscopic model focused on reactive performance was established.•A two-way coupling multi-scale model was proposed for catalytic distillation.•The simulation results were in good agreement with experimental data.•The effect of equivalent diameter of catalyst layer on efficiency factor was studied.A novel two-way coupling multi-scale model was proposed to investigate the catalytic distillation process. In the model, a microscopic model that focuses on the reactive performance of structure catalytic packing was used to calculate actual rate for catalytic distillation process, which is the basic parameter for process simulation. Furthermore, the traditional process simulation was used to provide proper boundary conditions for microscopic model. In order to validate the multi-scale model, heterogeneously catalyzed hydrolysis of methyl acetate was employed as a test system. The simulated final conversions of methyl acetate and catalyst layer efficiency factors were in good agreement with experimental results. The results indicated that as the equivalent diameter of catalyst layer decreases from 25.4 mm to 8.1 mm, the catalyst layer efficiency factor rises to 200% approximately. This study could provide a theoretical guide for the optimization of catalytic packing structure.

The solid acid SO42 −/TiO2 was prepared by immersion method and applied for synthesis of propylene glycol methyl ether acetate (PMA) through esterification reaction of propylene glycol monomethyl ether (PM) and acetic acid (HAc). The optimal catalyst preparation condition was determined by orthogonal analysis of parameters in a five-factor and four-level test. The obtained solid acid catalysts were characterized in detail by means of X-ray powder diffraction, thermogravimetry, pyridine adsorbed IR analysis, scanning electron microscopy, and BET surface area method. Synthesis of PMA was studied in this paper through experimental investigation of reaction conditions such as temperature, molar ratio of reactants, catalyst dosage and agitation speed. Based on its possible reaction mechanism, a pseudo-homogeneous kinetic model was established and its activation energies Ea+ and Ea−, 65.68 × 103 J·mol− 1 and 57.78 × 103 J·mol− 1, were estimated. To prepare shaped solid acid catalyst SO42 −/TiO2, the shaping method of impregnation–shaping–impregnation was applied. The optimal molding formulation of solid acid catalyst, obtained from the orthogonal test, was found to be binder 7 wt.%, reinforcing agent 20 wt.%, pore forming material 2.5 wt.%, and lubricant 4 wt.%. The results of performance test of catalyst demonstrated that the shaped solid acid catalyst exhibited high activity and stability.

•The catalyst is synthesized via a facile and time-saving copolymerization route.•Abundant mesopores and high surface areas play a key role in catalytic performance.•The catalyst is efficient for transesterification of soapberry oil to biodiesel.•The unique microsphere structure of catalyst allows for a convenient separation.Usually, traditional poly (ionic liquid)s are prepared to nanoparticles with high surface areas for achieving a quasi-homogeneous reaction system. In this work, a novel poly (ionic liquid) P(VB-VS)HSO4, synthesized by simply using ionic liquids immobilized on the 1-vinylimidazole-based crosslinked copolymer microsphere, was used as heterogeneous catalyst for transesterification of a novel non-edible feedstock soapberry oil to biodiesel. The structure, thermal stability and wetting property characteristics of the crosslinked copolymer microsphere particles and poly (ionic liquid) microspheres were investigated. The results indicated that ionic liquids were successfully functionalized on crosslinked copolymer microsphere, and P(VB-VS)HSO4 possessed high surface areas (100.1 m2/g), abundant meso-macropores (with diameter of ∼18.9 nm), good mechanical strength (81 N) and superior thermal stability. Benefiting from the unique structure features, these poly (ionic liquid) microspheres manifested excellent catalytic performance for transesterification of soapberry oil with methanol. A maximum fatty acid methyl esters (FAMEs) yield of 95.2% could be obtained under the response surface methodology (RSM) optimized conditions of 8.0 h reaction time, 29.1 methanol to oil molar ratio, and 8.7 wt% catalyst amount. Impressively, it was also efficient for the esterification of oleic acid, giving methyl oleate yield of 97.5%. Catalytic tests exhibited that P(VB-VS)HSO4 presented high catalytic activity and good reusability in comparison with traditional acid catalysts. The main physicochemical of the obtained soapberry biodiesel met the biodiesel standard ASTM D6751. Therefore, this work provides a cheap and facile route to the synthesis of size-controlled poly (ionic liquid) microspheres (the diameter of the catalyst was about 500 μm) for catalyzing the production of clean biofuels.Download high-res image (84KB)Download full-size image

Vapor–liquid equilibrium data for ethyl trifluoroacetate + trifluoroacetic acid, ethyl trifluoroacetate + ethanol, and trifluoroacetic acid + water at the pressure 101.3 kPa were measured with a modified Rose still. The thermodynamic consistency of the VLE data was confirmed by Herrington’s method. The VLE data were correlated by the NRTL and Wilson models with satisfactory results, and the interaction parameters of these mixtures were estimated.

A novel energy saving procedure for the synthesis and separation of dimethyl carbonate by reactive distillation is proposed, and its principle technical feasibility is demonstrated based on the physical properties of a dimethyl carbonate synthesis system. The steady-state simulation is performed with Aspen Plus, and the UNIQUAC-RK model is used in this work. The simulation result shows that the novel procedure can simplify the process and reduce energy consumption. The new procedure can save energy costs by 29.50% compared with the traditional processes. For further energy consumption reduction, heat integrations between the low-pressure column and the high-pressure column are adopted. It is found that energy savings of 53.80% are achieved for this novel process. The total annual costs of the four procedures are estimated and compared. It is shown that costs can be reduced by more than 31.54% by using the new processes. To sum up, the new procedure has a better economic investment than the original.

A reactive distillation process is proposed for the production of isopropanol by transesterification of isopropyl acetate (IPAc) with methanol using sodium methoxide solution as catalyst. The reaction kinetics experiments were carried out to correlate the parameters in a simple homogeneous kinetic model. On the basis of the fixed point analysis of residue curve maps, the feasibility of a reactive distillation process for the transesterification of isopropyl acetate and methanol was analyzed, and the results showed that the process is feasible under certain conditions. Reactive distillation experiments were set up, and several operation conditions were varied, such as reboiler duty, reflux ratio, space velocity, catalytic loading, and reactant ratio. The results show that the proper reboiler duty, reflux ratio, space velocity, catalytic loading, and MeOH to IPAc molar ratio are 314–365 kJ/h, 3.0, 0.73 m3/(m3 h), 0.4 wt %, and 2.5, respectively, and the conversion of IPAc is above 99%. Finally, the overall process flowsheet for synthesizing isopropanol is proposed.

A reactive distillation process is suggested for the production of cyclohexanol from cyclohexene and water using 1,4-dioxane as cosolvent and ion-exchange resin A-36 as catalyst. It not only can avoid the drawbacks of the conventional direct hydration of cyclohexene process, but also has more advantages than it, especially greatly improving conversion and reaction rate. On the basis of the fixed point analysis of residue curve maps, the feasibility of this novel process is analyzed and verified. The phase equilibrium and reaction kinetic experiments are carried out to correlate the parameters in activity coefficient model and kinetic model, respectively, which are necessary for calculating residue curve.

A good activated carbon adsorbent, KC-8, was used to remove residual p-xylene (PX) effectively after the extraction process of treating pure terephthalic acid (PTA) wastewater. The adsorption thermodynamics and kinetics of PX on activated carbon KC-8 were investigated completely and systematically. A series of adsorption equilibrium experiments were conducted under temperatures of (313.15, 323.15, and 333.15) K. The adsorption equilibrium data were fitted to Langmuir and Freundlich isothermal equations. The results showed that the adsorption equilibrium data were agreed with the Freundlich isothermal equation well. Thermodynamic analysis suggested ΔH > 0, ΔG < 0, and ΔS > 0. The adsorption of PX on KC-8 was a spontaneous physical and endothermic adsorption process. Kinetic studies indicated that the adsorption process of PX on activated carbon KC-8 could be described well by the pseudosecond-order kinetic model, and particle diffusion was the main rate-controlling step in the adsorption process.

The adsorption of Co(II) and Mn(II) onto the 001 × 7 × 7 ion-exchange resin has been studied. Batch experiments were performed to study the effects of various parameters such as stirring speed, temperature, dosage of resin, and pH on the adsorption process. The adsorption capacity (KF) for cobalt and manganese were calculated from the Freundlich adsorption isotherm. The adsorption of cobalt and manganese on the 001 × 7 × 7 ion-exchange resin followed the pseudosecond-order equation. The adsorption and desorption of Co(II) and Mn(II) onto the 001 × 7 × 7 ion-exchange resin were investigated by using a dynamic method. The effects of flow rate, temperature, and desorbant concentration were studied. The studies showed that this cation-exchange resin can be used as an efficient adsorbent material for the removal of cobalt and manganese from pure terephthalic acid (PTA) wastewater.

The acid-functionalized ionic liquid ([HSO3Pmim]HSO4) was synthesized by a two-step method. Nuclear magnetic resonance (NMR) and Fourier transform infrared spectroscopy (FT-IR) show that the synthesis method is feasible and high purity of ionic liquid can be obtained. Using [HSO3Pmim]HSO4 as the catalyst, we studied the reaction kinetics of synthesizing sec-butyl alcohol from sec-butyl acetate and methanol by transesterification in a high-pressure batch reactor. The effects of temperature, initial molar ratio of methanol to ester, and catalyst concentration on the conversion of sec-butyl acetate were studied. Based on its possible reaction mechanism, a homogeneous kinetic model was established. The results show that the reaction heat ΔH is 10.94 × 103 J·mol− 1, so the reaction is an endothermic reaction. The activation energies Ea + and Ea − are 60.38 × 103 and 49.44 × 103 J·mol− 1, respectively.The effect of temperature on the reaction rate and conversion of SBAC was investigated at the molar ratio of MeOH to SBAC of 3.5 and catalyst concentration of 1.5% (by mass). The reaction rate and the conversion increase with temperature, while the equilibrium conversion at different temperatures changes slightly.Download full-size image