Initial Activation Energy Research Articles

Cyclization kinetics of gel‐spun polyacrylonitrile/aldaric‐acid sugars using the isoconversional approach

AbstractComonomers, such as methacrylic acid, itaconic acid, and acrylic acid, can minimize the activation energy of polyacrylonitrile (PAN) cyclization through their nucleophilic reaction with pendant nitrile groups. An understanding of how these comonomers affect the kinetics of PAN cyclization inspired this study on how the isomeric sugars (glucaric acid(cis) and mucic acid(trans)) would influence PAN cyclization. Until now, researchers have characterized the cyclization of PAN by single activation energy; however, this approach using differential scanning calorimetry does not represent the conversion dependent kinetics of cyclization. The isoconversional method was used to evaluate exotherms for cyclization at three different heating rates while allowing the calculation of activation energy at incremental increases in conversion (α). The aldaric acid sugars reduced the activation energy of initiation by ~five times in comparison to values observed for neat PAN fiber and the ratio of (k1/k2) (where k1 is the rate constant for initiation and k2 is the rate constant for propagation) improved by ~2 orders of magnitude. Based on molecular dynamic simulations, hydrogen bonding between the aldaric acids sugars and PAN lowered the activation energy at the onset of cyclization.

Experimental research on the characteristics of the secondary oxidation heat of different unloaded coals

The oxidation heat characteristics of coal are key factors affecting the spontaneous combustion of coal. To study the thermal characteristics of the secondary oxidation of unloaded coal, a C600 microcalorimeter was used to test the unloaded coal under different stress conditions (0 MPa, 3 MPa, 6 MPa, 9 MPa, 12 MPa, 15 MPa) at 30–300 °C. The initial heat release temperature, heat release, and activation energy of coal were analyzed. The results shows that the initial heat release temperature of unloaded coal shows a trend of first increasing and then decreasing with increasing stress, and as the degree of oxidation increases, the maximum value of the initial heat release temperature point moves to a lower value. As the stress increases, the amount of heat release shows a fluctuation that first decreases and then increases, and as the degree of oxidation increases, the minimum heat release moves forward from 12 MPa for primary oxidation to 6 MPa for secondary oxidation. Similarly, the activation energy first increases and then decreases with increasing stress, and the maximum activation energy increases with increasing degree of oxidation, which is consistent with the trends of heat release. As the degree of oxidation increases, the overall performance of unloaded coal with increasing stress shows that the preoxidized coal sample is more susceptible to oxidation when it is reoxidized.

Comprehensive study of the crystallization behavior, thermal stability, and magnetic properties of Co66.5Si15.5B12Fe4Ni2 amorphous ribbon

Herein, the crystallization behavior, thermal stability, phase composition, and magnetic properties of Co66.5Si15.5B12Fe4Ni2 amorphous alloy were determined via differential scanning calorimetry, X-ray diffraction analysis, and vibrating sample magnetometry. The heating rate was found to strongly affect the glass-transition and crystallization behavior of Co66.5Si15.5B12Fe4Ni2 solidified ribbon. Based on the crystallization behavior, the relationship between the glass-transition temperature (Tg) and the heating rate (lnβ) was derived as Tg = 6lnβ + 709 and the glass-transition activation energy, initial crystallization activation energy, first crystallization peak activation energy, and the second crystallization peak activation energy were also calculated. Based on the results, the nucleation mechanism of the crystallization of Co66.5Si15.5B12Fe4Ni2 amorphous alloy and the crystallization products of the annealing crystallization process were discussed. The phase composition after short-term annealing at a low temperature was found to be β-Co + α-Co + Ni3Fe + Ni4B + Ni2Si. Following high-temperature, long-term annealing, Ni2Si disappeared completely and a new phase, FeSi, was formed. By studying the coercivity, remanence, saturation magnetization, and magnetic anisotropy of the alloy, we obtained the best processing parameters for comprehensive soft magnetic properties. The results provide guidance on the development of new soft magnetic materials.

Doping hematite with bismuth to enhance its catalytic and oxidizing properties

• Doping Fe 2 O 3 with Bi can significantly enhance its intrinsic reactivity. • The catalytic decomposition mechanism of HMX has been studied. • The ignition delay time is greatly shortened with the increase of Bi amount. • A high ignition performance of Al/Bix-Fe 2 O 3 can be obtained. Bismuth-cation modulated hematite (Bi-Fe 2 O 3 ) was prepared by a one-step hydrothermal method and used as a catalyst for the thermolysis of energetic materials (EMs) and oxidant in an Al-based thermite. The effects of the amount of Bi doped Fe 2 O 3 on the catalytic property and thermite behavior were investigated using differential scanning calorimetry (DSC). Thermogravimetry–infrared spectroscopy-mass spectrometry (TG/IR/MS) was used to study the thermal decomposition gases of cyclotetramethylenetetranitramine (HMX) with or without catalyst. Bi-Fe 2 O 3 was found to reduce the initial thermal decomposition temperature and activation energy of HMX, and change the decomposition mechanism. In addition, the thermite reaction of Al/Bi-Fe 2 O 3 is exothermic and faster than that of undoped Al/Fe 2 O 3 , resulting in more rapid energy release. Al/Bi-Fe 2 O 3 also shows a shorter ignition delay time than Al/Fe 2 O 3 . This study demonstrates Al/Bi-Fe 2 O 3 as an efficient advanced combustion catalyst for solid propellants.

Effect of grinding media on the synergistic characteristics of coal and biomass for the carbothermal reduction of silica

The synergistic characteristics of coal and biomass for the carbothermal reduction of silica were studied using different grinding media. The thermodynamic behavior and kinetic characteristics of the mixture components were evaluated by thermogravimetric analysis. The results showed that different grinding media strongly affected the synergistic effects of biomass and coal, especially the organic solvent used in this process. A lower initial reaction temperature and reaction activation energy were obtained by wet grinding technology or by introducing organic additives that promote synergistic processes and improve the structure of carbon materials. The carbothermal reduction of silica and mix components was also investigated, and it was found that a lower initial carbothermal reduction reaction temperature was observed by introducing organic additives. This study has important theoretical implications for improving the carbothermal reduction process of silica and comprehensively utilizing carbon resources.

Experimental Study on Loading Rate Effects on the Tensile Strength and Fracture Toughness of Rocks

The Brazilian method experiments were applied to investigate effects of loading rate on tensile strength of gabbro-diorite, marble, granite. The tensile strength was measured over a wide range of loading rate, $$\dot{\sigma } = 10^{ - 3} - 10^{2}$$ MPa s. Also the fracture toughness of marble, gabbro-diorite, dolerite were measured over a wide range of loading rate from 5 × 10−4 to 25 MPa m1/2/s by three-point bending of beams with a central narrow cut. The strength and fracture toughness of studied rocks are related to the loading rate by typical equations: $$\sigma = a + e\ln \dot{\sigma }$$ and $${\mathcal{K}}_{1c} = c + d\ln \dot{K}_{1}$$ in the range of loading rates of 10−3–102 MPa/s. A comparison of the characteristic fracture parameters for both types of tests showed the initial activation energy of fracture has the same values. The parameters of proportionality were compared on the basis of the integral strength criterion. The obtained parameters of the studied rocks allow extrapolating the results of measurements of strength and fracture toughness for longer periods, it is important for estimating the long-term stability of rock structures. The methodology for determining the characteristics of rock fracture from the loading rate in static fracture of rocks can be easily applied to other brittle materials.

Sublimation Kinetics for Individual Graphite and Graphene Nanoparticles (NPs): NP-to-NP Variations and Evolving Structure-Kinetics and Structure-Emissivity Relationships

A single nanoparticle (NP) mass spectrometry method was used to measure sublimation rates as a function of nanoparticle temperature (TNP) for sets of individual graphite and graphene NPs. Initially, the NP sublimation rates were ∼400 times faster than those for bulk graphite, and there were large NP-to-NP variations. Over time, the rates slowed substantially, though they remained well above the bulk rate. The initial activation energies (Ea values) were correspondingly low and doubled, as a few monolayers worth of material was sublimed from the surfaces. The high initial rates and low Ea values are attributed to large numbers of edge, defect, and other low coordination sites on the NP surfaces, and the changes are attributed to atomic-scale "smoothing" of the surface by preferential sublimation of the less stable sites. The emissivity of the NPs also changed after heating, more frequently increasing. The emissivity and sublimation rates were anticorrelated, leading to the conclusion that high densities of low-coordination sites on the NP surfaces enhance sublimation but suppress emissivity.

Experimental and kinetic modelling investigation on the effects of crystallinity on cellulose pyrolysis

The present work studies the effects of the crystallinity level of cellulose on the primary reactions during the slow and fast pyrolysis conducted in a wire-mesh reactor at 40 °C/min and 6000 °C/min, respectively. The sugars present in the water-soluble intermediates were analysed in a chromatogram equipped with a Q-exactive high-resolution mass spectrometer. The products in the washed primary tars were quantified through GC/MS. Slow pyrolysis experiments were also performed in a thermogravimetric analyser at four different heating rates (5, 10, 20 and 40 °C/min). All experimental data was used to develop a modified kinetic model that considers the effects of crystallinity on cellulose pyrolysis, which is based on the cellulose sub-mechanism of the Bio-PoliMi kinetic model. The kinetic parameters of each reaction in the modified model were calibrated using a two-step fitting procedure. The experimental results show that low crystallinity promotes the dehydration reactions in the cellulose solid base and the formation of oligosaccharides in the water-soluble reaction intermediates, increasing the formation of furans and decreasing that of levoglucosan in the final primary tar. The effect of crystallinity on the pyrolysis characteristics of cellulose is weaker during fast pyrolysis than during slow pyrolysis. The isoconversional kinetic approach of cellulose pyrolysis presents a low initial activation energy of the pyrolysis of amorphous cellulose, which is close to the activation energy of cellulose hydrolysis. Assuming that the amorphous region of cellulose decomposition path prefers depolymerization through hydrolysis accompanied by the dehydration of nearby hydroxyl group, the modified kinetic model succeeds to predict the effect of crystallinity on the thermal stability and the yields of char, levoglucosan and furans during cellulose pyrolysis.

Experimental investigation of the carbon dioxide effect on the devolatilization and combustion of a coal and sugarcane bagasse

This study investigates the CO2 influence on thermal decomposition of sugarcane bagasse and a low-rank coal. Experiments at low and high heating rates were performed under different ratios of CO2/O2/N2 atmospheres to evaluate devolatilization, char combustion, burnout, SO2, NO and CO emissions. When N2 was replaced by CO2, the coal combustion was enhanced and the kinetic study presented lower initial activation energy, the devolatilization yield was higher and the CO2-char presented higher reactivity compared to N2-char. The results obtained for sugarcane bagasse presented opposite behavior, and lower conversions and char reactivity were observed. The kinetic study showed a negative influence on sugarcane bagasse devolatilization and the activation energy was significantly higher under CO2 than under N2 (189 kJ mol−1 and 86 kJ mol−1, respectively). The difference between the fuels can be attributed to the higher volatiles content of the sugarcane bagasse, in which the suppression caused by CO2 partial pressure under 80% CO2 atmosphere was more pronounced for biomass than for coal, confirmed during devolatilization in the DTA results. Regarding the pollutant emissions, the NO formation decreased and the CO formation increased when N2 was replaced by CO2. No conclusive trend was observed for the SO2 species.

From the Kinetic Theory of Gases to the Kinetics of Rate Processes: On the Verge of the Thermodynamic and Kinetic Limits.

A variety of current experiments and molecular dynamics computations are expanding our understanding of rate processes occurring in extreme environments, especially at low temperatures, where deviations from linearity of Arrhenius plots are revealed. The thermodynamic behavior of molecular systems is determined at a specific temperature within conditions on large volume and number of particles at a given density (the thermodynamic limit): on the other side, kinetic features are intuitively perceived as defined in a range between the extreme temperatures, which limit the existence of each specific phase. In this paper, extending the statistical mechanics approach due to Fowler and collaborators, ensembles and partition functions are defined to evaluate initial state averages and activation energies involved in the kinetics of rate processes. A key step is delayed access to the thermodynamic limit when conditions on a large volume and number of particles are not fulfilled: the involved mathematical analysis requires consideration of the role of the succession for the exponential function due to Euler, precursor to the Poisson and Boltzmann classical distributions, recently discussed. Arguments are presented to demonstrate that a universal feature emerges: Convex Arrhenius plots (super-Arrhenius behavior) as temperature decreases are amply documented in progressively wider contexts, such as viscosity and glass transitions, biological processes, enzymatic catalysis, plasma catalysis, geochemical fluidity, and chemical reactions involving collective phenomena. The treatment expands the classical Tolman’s theorem formulated quantally by Fowler and Guggenheim: the activation energy of processes is related to the averages of microscopic energies. We previously introduced the concept of “transitivity”, a function that compactly accounts for the development of heuristic formulas and suggests the search for universal behavior. The velocity distribution function far from the thermodynamic limit is illustrated; the fraction of molecules with energy in excess of a certain threshold for the description of the kinetics of low-temperature transitions and of non-equilibrium reaction rates is derived. Uniform extension beyond the classical case to include quantum tunneling (leading to the concavity of plots, sub-Arrhenius behavior) and to Fermi and Bose statistics has been considered elsewhere. A companion paper presents a computational code permitting applications to a variety of phenomena and provides further examples.

Effect of 5-membered bicyclic hydrocarbon additives on nanostructural disorder and oxidative reactivity of diffusion flame-generated diesel soot

Soot emission from diesel engines is of serious concern, as it is carcinogenic and remains suspended in air for a long time to cause adverse effects on human health and the environment. A way to reduce soot emission is by altering soot nanostructures by introducing fringe curvatures to enhance reactivity and increase oxidation. Such disorder in soot nanostructure can be initiated by the introduction of 5-membered rings into 6-membered, graphite-like soot structures. This study investigates the effect of the addition of norbornane, a saturated, 5-membered bicyclic hydrocarbon additive to diesel on the physicochemical properties, sooting propensity, structural disorders, and the oxidative reactivity of soot. The physicochemical analysis revealed that the threshold sooting index (TSI) of the blend is reduced to 29.5 at an optimum blending percentage of 10% norbornane-90% Diesel (NBD) as compared to the TSI of 37 for diesel. The analyses using XRD, Raman, HRTEM, and EDX indicated that the addition of this additive resulted in an increased soot nanostructural disorder, smaller PAH size, increased fringe curvature, and significantly greater aliphatic content in soot as compared to an unsaturated 5-membered bicyclic additive, dicyclopentadiene (DCPD). The reactivity studies confirmed that NBD soot is easily oxidized in air, since it requires a lower initial activation energy (90 kJ/mol) as compared to DCPD (120 kJ/mol) and pure diesel soots (170 kJ/mol). Thus, norbornane, a saturated 5-membered bicyclic compound, which is available as a by-product of polymer industry and in crude oil, can serve as a potential fuel additive for designing advanced fuels.

Effect of CeH2.73-CeO2 Composites on the Desorption Properties of Mg2NiH4.

A series of CeH2.73/CeO2 composites with different ratios of hydride and oxide phases are prepared from the pure cerium hydride via oxidation treatments in the air at room temperature, and they are subsequently doped into Mg2NiH4 by ball milling. The desorption properties of the as-prepared Mg2NiH4+CeH2.73/CeO2 composites are studied by thermogravimetry and differential scanning calorimetery. Microstructures are studied by scanning electron microscopy and transmission electron microscopy, and the phase transitions during dehydrogenation are analyzed through in situ X-ray diffraction. Results show that the initial dehydrogenation temperature and activation energy of Mg2NiH4 are maximally reduced by doping the CeH2.73/CeO2 composite with the same molar ratio of cerium hydride and oxide. In this case, the CeH2.73/CeO2 composite has the largest density of interface among them, and the hydrogen release effect at the interface between cerium hydride and oxide plays an efficient catalytic role in enhancing the hydrogen desorption properties of Mg2NiH4.

Preparation of Few-Layered WS2 and Its Thermal Catalysis for Dihydroxylammonium-5,5′-Bistetrazole-1,1′-Diolate

In this study, few-layered tungsten disulfide (WS2) was prepared using a liquid phase exfoliation (LPE) method, and its thermal catalytic effects on an important kind of energetic salts, dihydroxylammonium-5,5′-bistetrazole-1,1′-diolate (TKX-50), were investigated. Few-layered WS2 nanosheets were obtained successfully from LPE process. And the effects of the catalytic activity of the bulk and few-layered WS2 on the thermal decomposition behavior of TKX-50 were studied by using synchronous thermal analysis (STA). Moreover, the thermal analysis data was analyzed furtherly by using the thermokinetic software AKTS. The results showed the WS2 materials had an intrinsic thermal catalysis performance for TKX-50 thermal decomposition. With the few-layered WS2 added, the initial decomposition temperature and activation energy (Ea) of TKX-50 had been decreased more efficiently. A possible thermal catalysis decomposition mechanism was proposed based on WS2. Two dimensional-layered semiconductor WS2 materials under thermal excitation can promote the primary decomposition of TKX-50 by enhancing the H-transfer progress.

Stress Relaxation Aging Behavior and Constitutive Modelling of AA7150-T7751 under Different Temperatures, Initial Stress Levels and Pre-Strains

Age forming is an advanced manufacture technology for forming large aluminum panels. Temperature, initial stress level and pre-strains have a great effect on the formability and performance. The stress relaxation aging behavior of AA7150-T7751 under different temperatures, initial stress levels and pre-strains was studied through stress relaxation tests, tensile tests and TEM observations. The results show that the formability can be improved with the increase of temperature, initial stress levels and pre-strains. Deformation mechanisms during stress relaxation of the material were analyzed on the basis of creep stress exponent and apparent activation energy. The aging precipitates of the studied alloy were not sensitive to the age forming conditions, but drastically coarsened at over aging temperature, which decreased the mechanical properties. In addition, the relationship between stress relaxation behavior and aging strengthening is discussed. Based on the dislocation theory and the modified Arrhenius equation, a stress relaxation constitutive equation considering the initial mobile dislocation density and temperature dependent activation energy was established. This model can predict very well the stress relaxation behavior under various temperature, stress level and pre-strain conditions, with an average error of 2%.

Reactive molecular dynamics simulation on thermal decomposition of n-heptane and methylcyclohexane initiated by nitroethane

Normal alkanes and cycloalkanes are important components of endothermic hydrocarbon fuels. The present work conducts the reactive molecular dynamics (RMD) simulations based on reactive force field to compare the thermal cracking of n-heptane and methylcyclohexane (MCH) with the same carbon atom number initiated by nitroethane, focusing on initial decomposition temperature, intermediates and product distribution, and the related kinetics. From the RMD simulations, we find nitroethane can accelerate both n-heptane and MCH decompositions, since the C–NO2 bond rupture of nitroethane can proceed at relatively lower temperatures to produce the reactive radicals compared to the C–C bond cleavage of n-heptane and MCH to start the free radical chain reactions, but the promoting effect becomes weaker after it reaches a certain level with temperature. Reasonable Arrhenius parameters estimated from RMD simulations based on first-order kinetic analysis compare well with experimental results. The observed difference of pyrolysis behaviors and kinetic parameters between n-heptane and MCH can be ascribed to their molecular structure, coinciding with experimental observations. In the presence of nitroethane, reductions of initial temperature and activation energy for n-heptane decomposition are larger than those for MCH decomposition. More alkenes are observed in n-heptane decomposition compared to MCH decomposition. Due to the endothermic capacities of fuel being sensitive to the yields of alkenes, more heat could be absorbed by the n-heptane decomposition. These results indicate that RMD simulations can provide important insights at the atomistic level on the difference of decomposition behaviors between normal alkanes and cycloalkanes initiated by nitroethane under supercritical conditions.

A Study on the Use of Water as a Medium for the Thermal Inactivation of Endogenous Lipase in Oil of Palm Fruit

The heat treatment of oil palm fruit using saturated steam (413 K) in conventional oil palm processing has been reported to be ineffective in terms of heat distribution and penetration into the fruit bunch inner layer; hence, there is a desire to explore other alternative processes. In this study, oil palm fruit was treated in water at temperatures between 308 K and 343 K. The effects of the treatment on the in vivo activity of the lipase, the abscission layer of the fruit, and the integrity of the oil globule membrane were observed. The results showed in vivo residual lipase activity to be almost completely inactivated after 40 min of heat treatment at 343 K. The micrograph of the fruit mesocarp exhibited disintegration of the oil globule membrane as well as dissolution of the pectin layer architecture of the abscission zone after the treatment at this temperature. A dynamic mathematical modeling of heat transfer was employed, and coupled with reaction kinetics of lipase inactivation. The inactivation kinetics was found to be a non-elementary reaction, and the initial rate constant, k0dec, and activation energy, Edec, of the reaction were estimated to be 0.035 U−0.85/kg-mes−0.85⋅min and 153,052 kJ/kmol, respectively. The findings suggested the viability of water as a medium of heat treatment instead of the conventional steam treatment in oil palm processing.

Thermal hazard evaluation of tert-butylperoxy-2-ethylhexanoate mixed with H2O and NaOH solution

Tert-butylperoxy-2-ethylhexanoate (TBEC)—an easily decomposable organic peroxide—is widely used as a polymerization initiator in industrial production. Sodium hydroxide solution and water are common impurities in the polymerization process. In this study, exothermic onset temperature (T0) and heat of decomposition (ΔH) of TBEC with impurities were obtained through differential scanning calorimetry. In addition, maximum pressure (Pmax), maximum temperature (Tmax), and adiabatic temperature rise (ΔTad) were obtained through accelerated rate calorimetry (ARC). Apparent activation energy (Ea) scores for pure TBEC and TBEC mixed with water (TBEC/H2O) and sodium hydroxide (TBEC/NaOH) were calculated. Subsequently, based on experimental data obtained through ARC, the self-accelerating decomposition temperature and temperature at the time to maximum rate under adiabatic conditions were calculated for 24 h (TD24) and 8 h (TD8). The experimental results indicated that H2O negligibly affected T0 but decreased ΔH, Pmax, Tmax, and ΔTad. Moreover, addition of H2O increased the TD24 and TD8 of TBEC. Thus, the thermal hazard of TBEC was reduced by addition of H2O. Addition of NaOH solution increased the complexity of the reaction because the initial decomposition temperature and activation energy were negatively correlated to the content of NaOH in the solution.

Influence of Monomers on the Decomposition Rate of Polymerization Initiators: Quantum-Chemical Calculation of Optimal Structures of Forming Complexes and Their Degradation and Polymerization Initiation Mechanisms

Using EPR spectroscopy, it has been established that monomers affect the decomposition rate of their polymerization initiators by forming complexes with them. Several structures of the complexes have been optimized, and their decomposition mechanisms, the activation energies of the chain initiation and propagation reactions, and the heat of polymerization have been determined by means of quantum chemistry methods. In the absence of radical inhibitors (evacuation), the polymerization proceeds with high efficiency (98%) at room temperature without stimulation of the system with external energy.

High-sulfur capacity and regenerable Zn-based sorbents derived from layered double hydroxide for hot coal gas desulfurization.

The Zn-Al mixed metal oxide (ZnAl-MMO) with a plate-like structure was derived from Zn-Al layered double hydroxide. The ZnAl-MMO with a Zn/Al molar ratio of 3:1 exhibits superior absorption ability for H2S in a simulated coal gas at 600 ℃ due to the special structure of the ZnAl-MMO. Besides ZnS, elemental sulfur is also produced during the desulfurization process. The deactivation model could well simulate the absorption behavior of H2S. The sulfidation reaction over the sorbent shows large initial reaction rate constants (1110-5390 m3 min-1 kg-1) and low activation energy (29.5 kJ mol-1). The regeneration rate of the used sorbent can reach 99.8% under the optimum conditions. The regenerated sorbents still show high sulfur capacity (ca. 30%), implying its great application potential for industrial-scale desulfurization of the hot coal gas.

Effect of Hydrogen Bond Donor on the Physical Properties of Benzyltriethylammonium Chloride Based Deep Eutectic Solvents and Their Usage in 2-Ethyl-Hexyl Acetate Synthesis as a Catalyst

Deep eutectic solvents (DES) containing benzyl triethylammonium chloride (BTEAC) as a hydrogen bond acceptor (HBA) and p-toluene sulfonic acid (PTSA), citric acid (CA), and oxalic acid (OX) as a hydrogen bond donor (HBD) were formed at their respective eutectic points. The physical properties such as pH, ionic conductivity, viscosity, density, and refractive index were measured between 293 and 333 K. Viscosity values as low as 0.21 Pa·s and conductivity values as high as 8 mS/cm were achieved, where the pH values of each DES proved to be extremely low. The effect of HBD on the physical properties was investigated and was found to be very significant. Also, the catalytic application of BTEAC based DES in the esterification reaction of the acetic acid with 2-ethyl-hexanol was studied, and the activation energy was obtained using initial reaction rates. The results showed that very high initial reaction rates and low activation energy can be achieved when catalyzed by DES which was formed using BTEAC and PTSA.