Esterification Of Propionic Acid Research Articles

On the modelling and surface response analysis of a non-conventional wall-cooled solid/gas bioreactor with application in esterification

Solid/gas biocatalysis is, nowadays, an attractive discipline in biotechnology for applying synthesis reactions. The design of the solid/gas bioreactor is, nevertheless, the main engineering challenge for its application at full scale. Although modeling is the most reliable engineering tool to design a reaction technology and guide the experimental work, as far as the authors know, there is not, today, a mathematical model for the solid/gas bioreactor. To this end, this work is aimed at developing a pseudo-continuous model for a wall-cooled packed-bed reactor for solid/gas biocatalysis. Esterification of propionic acid and isobutyl alcohol on supported lipases extracted from Candida antarctica is implemented as the case study because of the importance of isobutyl propionate in the commodities market. The proposal and construction of the mathematical model are based on reactor engineering principles. Thus, the pseudo-continuous model is applied for carrying out parametric sensitivity and surface response analyses. The former contributes to understanding the complex microscopic interaction between thermodynamics, kinetics, and transport phenomena at the studied operating conditions and selected geometrical settings; while the latter allows the identification of the operational window where the biocatalyst meets its optimal macroscopic performance without having the well-known computational cost due to the time required to solve pseudo-continuous models accounting for the bioreactor heterogeneity and fluid dynamics. The pseudo-continuous model constitutes a valuable tool for future studies focused on either providing a deeper understanding of the solid/gas biocatalytic esterification or carrying out the conceptual design and operation of the solid/gas bioreactor.

The kinetic model of the combined heterogeneously catalyzed condensation and esterification of propionic acid and methyl propionate with formaldehyde and methanol

In this work we aim for developing a kinetic model for the methyl methacrylate and methacrylic acid synthesis by the combined condensation and esterification of methyl propionate and propionic acid with formaldehyde and methanol in the presence of the silica-supported boron-phosphorus-oxide catalyst promoted by oxides of tungsten and zirconium. The dependencies of the formation rates of methyl methacrylate, methacrylic acid and diethyl ketone from the concentrations of methyl propionate, propionic acid, formaldehyde and methanol were studied, and reaction orders of every product formation with respect to each reagent were determined. Methacrylic acid is formed predominantly by condensation of methyl propionate with formaldehyde, and methyl methacrylate hydrolysis is insignificantly. The methyl methacrylate formation reaction rate is limited by the methyl propionate adsorption rate on the catalyst surface, and both reactions of methyl methacrylate and methacrylic acid formation are inhibited due to adsorption of formaldehyde, propionic acid and methanol. Based on obtained data, the reaction scheme was offered, which includes formation of intermediates such as 3-hydroxy-2-methylpropanoic acid, its methyl ester and 3,3-dihydroxy-2-methylpentanoic acid. From this reaction scheme the kinetic model was derived using steady state approximation. The reaction rate constants and their activation energies for this model were calculated from experimental data. Validity of the model was experimentally confirmed by the correlation between experimental and theoretically calculated data. Therefore, the developed kinetic model satisfactorily describes the process of the combined condensation and esterification of methyl propionate and propionic acid with formaldehyde and methanol as well as partial cases of condensation of methyl propionate with formaldehyde and propionic acid with formaldehyde, and is suitable for process optimization and technological calculations.

Production of isoamyl propionate: use of Amberlyst – 15 in batch reactor and packed bed reactor

ABSTRACT The synthesis of isoamyl propionate by esterification of propionic acid with isoamyl alcohol is presented in this work using ion exchange resin Amberlyst-15. In batch kinetics, about 33% conversion of acid was obtained in 3 hours under the conditions such as temperature of 343 K, 1:3 molar ratio, Amberlyst-15 catalyst with 5% loading (w/w of limiting component). For enhancing the performance of the reaction and to make the process continuous, the reaction was conducted in a packed bed reactor. Conversion of 53% was obtained in 3 hours, thus indicating the possibility of process intensification.

Ketonic decarboxylation and esterification of propionic acid over beta zeolites

Abstract The present work reports the nanocrystalline Beta zeolites synthesis from the high concentration hydrogels and their behavior in the propionic acid esterification with cyclohexanol and in the ketonic decarboxylation of propionic acid. The solids were characterized by X-ray diffraction, N2-adsorption, transmission and scanning electron microscopy, diffuse reflectance infrared spectroscopy. Three types of acid sites has been evidenced in Beta zeolites: external silanol groups (Si–OH) (with weakly acidity), Si–OH–Al groups (with strong Bronsted acidity) and silanol nests associated with the defect sites (with Lewis acidity). In the propionic acid esterification with cyclohexanol, the highest cyclohexyl propionate yield was obtained over the sample with the highest specific surface area, the highest mesopore volume and the highest Bronsted acidity. In the propionic acid ketonic decarboxylation, the catalyst with the lowest ratio Bronsted acid sites/Lewis acid sites showed the highest activity and selectivity towards 3-pentanone compared to the other two which are more selective towards propanol.

Vapor–Liquid Equilibria and Conceptual Design of Extractive Distillation for Separating Ethanol and Ethyl Propionate

Ethyl propionate is usually produced from esterification of propionic acid and ethanol in the industry. However, the purification of ethyl propionate remains a challenge because the unreacted ethanol forms an azeotrope with ethyl propionate. In this work, extractive distillation was adopted, and isobutyl acetate was chosen as the entrainer to separate the mixture of ethanol and ethyl propionate. The vapor–liquid equilibria for binary systems of ethanol/ethyl propionate + isobutyl acetate were measured at atmospheric pressure, and the experiment data were correlated with the nonrandom two-liquid model, universal quasi-chemical model, and Wilson model. Then, the thermodynamic analyses, using residue curves, isovolatility curves, and extractive composition profile of the ethanol + ethyl propionate + isobutyl acetate ternary system, were performed to confirm the feasibility of separating the azeotrope with isobutyl acetate as the entrainer. The extractive distillation process was designed and optimized by the sequential iterative procedure based on the total annual cost. Results of the extractive distillation simulation also verified the reliability of thermodynamic analysis.

Sulphonated Tea Waste Carbon Catalyzed Esterification of Propionic Acid with Ethyl Alcohol: Modulus and Rate Constant Estimation

In this research paper, sulphonated carbon catalyst was prepared from left over (used) tea waste obtained after extraction of tea. The surface morphology of sulphonated tea waste carbon catalyst (STWCC) was accomplished using FTIR, SEM and BET. The structure of catalyst was found porous and exhibited excellent catalytic properties. The surface area of STWCC was estimated as 381m2/g. Moreover, catalyst was abound with the existence of many functional elements and most of them belonged to electron withdrawing groups, whose presence can be availed in hindering the leaching of catalyst. STWCC was employed in the esterification of propionic acid and ethyl alcohol at 1 to 3% (wt/wt) catalyst concentration and at temperatures 328 to 348 K. It was observed that, the rate of reaction as well as conversion of propionic acid increased with increasing catalyst loading and reaction temperature. The values of effectiveness factor, porosity / tortuosity ratio was also estimated and obtained as 0.99, 0.2 respectively. The effective diffusivity of STWCC was estimated at different temperature. The internal as well as external diffusion limitation were determined by Weisz-Prater criterion and found to be absent. Concisely, the novelty of present work is claimed on the basis of source of tea waste available, legal aspects, cost and end product application. The previous researchers reported the cost of tea waste from processing industries approximately Rs 25 to 30 per kg. Whereas the leftover tea waste mentioned in the present work is available for free of cost. Moreover, industrial tea waste producers are bound to follow the various protocols of waste management. Furthermore, the yield and surface area of activated carbon reported by them was low. Another inference that can be drawn that all the previous research focused their attention on synthesis of the adsorbent for purification of biodiesel, wastewater, etc. Thus, we claim for the novelty to reuse leftover tea waste to synthesize catalyst and subsequently apply in the esterification of propionic acid.

Enzymatic Kinetics of Solvent-free Esterification with Bio-imprinted Lipase

To avoid the use of compounds that burden the environment, a solvent-free enzymatic<br /> reaction was the focus of this study. Investigated were the catalytic activities and kinetics of lipases that were pretreated with carboxylic acids for the solvent-free esterification of propionic acid with isoamyl alcohol. The enhancements of the esterification yields and rates by the bio-imprinting effects of carboxylic acids were observed. We found no inhibition of isoamyl alcohol on the solvent-free enzymatic esterification, and obtained a large imprinting effect under a largely excessive amount of isoamyl alcohol to propionic acid. From the kinetic analysis, the imprinting of lipases mainly enhanced the catalytic reaction rate constant rather than the affinity between lipase and propionic acid compared with untreated lipase. The bio-imprinting treatment of lipase is found to be very effective for the yield and kinetics in solvent-free esterification.

PROPİYONİK ASİTİN İZOBUTİL ALKOL İLE AMBERLYST 36 VE AMBERLYST 70 KATALİZÖRLERİ VARLIĞINDA ESTERLEŞME KİNETİĞİ

The esterification of propionic acid with isobutyl alcohol has been studied in a batch reactor in the presence of Amberlyst 36 and Amberlyst 70 catalysts. Reaction parameters applied in this study are speed of agitation (500-1000 rpm), particle size of catalyst (400-600 µm, 600+ µm), temperature (318-348 K) and catalyst loading (4-12 g-dry resin/L). A pseudo-homogeneous kinetic model was derived and all thermodynamic and kinetic parameters were calculated. Forward reaction rate constant for Amberlyst 36 and Amberlyst 70 determined as follows: k_1=160171 exp⁡((-56689)/RT) (L mol-1 min-1) k_1=293314 exp⁡((-57292)/RT) (L mol-1 min-1) In a comparison of the two catalysts used in this study, experimental results showed that Amberlyst 70 is more effective than Amberlyst 36.

Catalytic Applications of Large Pore Sulfonic Acid-Functionalized SBA-15 Mesoporous Silica for Esterification

Abstract We report the preparation of pore expanded and sulfonic acid functionalized mesoporous silica catalysts by using different kinds of swelling agents such as 1,3,5-trimethyl benzene (TMB), n-decane (D), n-tridecane (TD), and n-hexadecane (HD) at two different ratios of swelling agent/surfactant. Non-swelled mesoporous silica catalyst, SBA-15-SO3H, was also prepared for comparison. The performance of the sulfonic acid functionalized solid acid catalysts by using one-pot synthesis procedure was evaluated in terms of their catalytic activity in the esterification of propionic acid with methanol. The catalysts have been characterized by X-ray diffraction to investigate the phase transition between the hexagonally packed arrangement of cylindrical pores and mesocellular silica foams (MCF), and N2 adsorption/desorption technique in terms of pore size and distributions. It was concluded from the XRD and N2 adsorption/desorption analyses that hexagonally packed and cylindrical pore structure is maintained only for low ratio of swelling agent/surfactant and the increase of the dimension of a template micelle is accompanied by an increase in structural disruption, which was attributed to the phase transition from highly ordered hexagonal arrangement to mesocellular foam (MCF) phase with large nodded pore structures rather than cylindrical pores. Among the different swelling agents, TMB and D were found to be effective for the increase in pore diameter (up to 8 and 7.8 nm), whereas, TD and HD (6.6 nm) are effective to maintain the ordered X-ray diffraction patterns resulting mesoporous materials without giving enlargement of pore diameter in comparison with TMB and D. Pore expanded catalysts, SBA-15-SO3H-TMB-0.1 and SBA-15-SO3H-D-0.1, exhibit 68 and 43% enhancement in turnover frequency toward propionic acid methanol esterification, respectively, over non-swelled SBA-15-SO3H, despite possessing similar acid strengths. The increased activity especially for SBA-15-SO3H-TMB-0.1 and SBA-15-SO3H-D-0.1 likely reflects the accessibility to the active sulfonic acid sites as well as acidity.

A comparative study on the synthesis of ethyl propionate in a pervaporation membrane reactor

In this study, esterification of propionic acid with ethanol over a tungstophosphoric acid catalyst was conducted in a batch reactor and in a pervaporation membrane reactor (MR). The performance of the esterification was determined in terms of the propionic acid conversion. Effects of the reaction temperature within the range of 50 °C–70 °C, the initial molar ratio of reactants (1:1, 2:1, 3:1), and the catalyst concentration (10–20 g cat/kg reactant) on the propionic acid conversion were investigated. A poly(vinyl alcohol) membrane was prepared and used to remove the water from the reaction media simultaneously. Conversion results of the batch reactor (BR) and the MR were compared. Results showed that the conversion of the reaction was improved by using MR. As the highest conversion of 80.7% was obtained in the BR, 92.9% of acid conversion was achieved in the MR at 70 °C when the alcohol:acid molar ratio was 3:1. The conversion of the propionic acid-ethanol esterification was enhanced between the values from 15% to 27% by using MR. Activation energy of the reaction carried out in the MR was found as 39.6 kJ/mol.

Microwave assisted solvent-free synthesis of n -butyl propionate by immobilized lipase as catalyst

Abstract Operational simplicity, solvent free media, potential reusability of catalyst and wide functional group tolerance are the advantages for solvent free synthesis under microwave irradiation technique. In the current work, n-butyl propionate was synthesized by esterification of propionic acid with n-butanol using different immobilized enzymes under microwave irradiation vis-a-vis conventional heating. Commercially available lipases such as Lypozyme RM IM, Lypozyme TLIM and Novozym 435 (Candida antarctica lipase B) were screened for n-butyl propionate synthesis from propionic acid and n-butanol for which Novozym 435 showed the best catalytic activity. n-Butyl propionate is widely used in flavour, painting, enamels, appliance coating and similar processes. In 8 h 92% conversion was achieved at 60 °C with 1:12 mol ratio of propionic acid to n-butanol under microwave irradiation. Systematic studies were done to understand mechanism and kinetics of reaction. By studying the Lineweaver-Burk plots it was found that the lines were intersecting at a point, showing that the reaction follows ternary complex mechanism with inhibition by n-butanol.

Synthesis of cenosphere supported heterogeneous catalyst and its performance in esterification reaction

ABSTRACT A heterogeneous catalyst has been developed from cenosphere, a byproduct generated in thermal power plant. The performance of catalyst was investigated in the esterification of propionic acid and ethanol. The catalyst was characterized by FTIR, X-ray diffraction, field emission scanning electron microscope, and Brunauer–Emmett–Teller surface area and surface acidity analysis. The response surface methodology (RSM) with the Box–Behnken design was employed to design the experiments as well as to optimize the various process parameters such as catalyst loading, alcohol/acid molar ratio, and reaction temperature. The characterization revealed that the cenosphere supported catalyst possessed increased amounts of silica content, surface hydroxyl groups, surface area as well as surface acidity as compared with that of pristine cenosphere. The catalyst showed an excellent activity in the esterification reaction with a maximum conversion up to 91%. The RSM model well fitted the experimental data and predicted optimal conditions which were validated experimentally with a good agreement. The recyclability study showed a significant catalytic stability up to three reaction cycles. This study reveals that the cenosphere supported catalyst can be used as a potential catalyst in the esterification reaction may replace the conventional homogeneous acid catalyst.

Magnetic Vinylphenyl Boronic Acid Microparticles for Surface Catalytic Performance in Esterification of Propionic Acid with Methanol

Magnetic vinylphenyl boronic acid microparticles, poly(ethylene glycol dimethacrylate-vinylphenyl boronic acid) [m-poly(EGDMA-VPBA)], produced by suspension polymerization, was found to be efficient solid acid catalyst for the esterification of methanol and propionic acid. Characterization techniques such as FT-IR, Elemental analyses, ICP-AES, ESR, SEM and N 2 sorption showed that both of Fe 3 O 4 and H 2 SO 4 are bonded to the polymer successfully. Esterification was studied for different molar percentages of H 2 SO 4 at temperature range of 50-70 o C. The apparent activation energy was found to be 27.7 kj.mol -1 for 10% H 2 SO 4 doped m-poly(EGDMA-VPBA). Combining of strong acid H 2 SO 4 with m-poly(EGDMA-VPBA), leads to materials with different functional properties. In addition, H 2 SO 4 species could be introduced into the structure as acid centers, therefore this micro-dimensional catalyst has potential candidate for applications in the catalytic esterifications such as propionic acid with methanol.

Esterification of propionic acid with isopropyl alcohol over ion exchange resins: Optimization and kinetics

The esterification of propionic acid with isopropyl alcohol was studied in an isothermal batch reactor. The activities of three different types of ion exchange resin catalysts (Amberlyst 15, Amberlyst 70 and Dowex 50 WX8) were investigated, and Amberlyst 15 was found to be an effective catalyst for the reaction. The effects of process parameters, namely, catalyst loading, alcohol to acid molar ratio and reaction temperature, were studied and optimized. Response surface methodology (RSM) was applied to optimize the process parameters as well as to investigate the interaction between process parameters. The internal and external diffusion limitations were found to be absent at a stirring speed of 500 rpm. The RSM model predicted response (83.26%) was verified experimentally with a good agreement of experimental value (83.62±0.39%). Moreover, the kinetics was studied and the Langmuir-Hinshelwood model was used to fit the kinetic data.

Solvent effects on esterification equilibria

Solvents are known to have strong impacts on the yields of equilibrium reactions. This work focuses on the thermodynamic investigation of these solvent effects on esterification reactions of acetic acid and propionic acid with ethanol. Esterification of acetic acid was performed in the solvents acetone, acetonitrile (ACN), dimethylformamide (DMF), and tetrahydrofurane as well as in mixtures thereof. ACN promotes the esterification of acetic acid, whereas it is strongly suppressed by DMF. The esterification of propionic acid was investigated with various reactant concentrations in acetone. The experimental equilibrium data in pure solvents and solvent mixtures were modeled using the thermodynamic equilibrium constant Ka and the reactant/product activity coefficients predicted by the perturbed chain‐statistical associating fluid theory (PC‐SAFT). For a given Ka, PC‐SAFT is able to predict the influence of the solvent and even solvent mixtures on the equilibrium concentrations of esterification in almost quantitative agreement with the experimental data. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3000–3011, 2015

Isoamyl propionate production by reactive distillation

In this work, the production of isoamyl propionate by esterification of propionic acid with isoamyl alcohol, via continuous reactive distillation was studied. Conceptual design of the reactive distillation system was conceived from the construction of conventional and reactive residue curves maps at 101.32kPa. The process was modeled using an equilibrium-stage approach and simulated with Aspen Plus® 7.3. Experimental evaluation of the process was carried out in a 8cm ID×6m tall pilot-scale glass reactive-column, using Amberlyst® 70 ion exchange resin as catalyst contained in a KATAPAK® SP-11 structured packing. Reasonably good agreement between experimental and simulation results was observed. For a single equimolar feed, propionic acid conversions over 96% and isoamyl propionate purities over 98wt.% in the bottoms product were obtained. Results obtained in this work can be used for scale-up studies of an industrial reactive distillation operation as a possible alternative to upgrade isoamyl alcohol from the bio-ethanol industry.

Synthesis of isobutyl propionate using immobilized lipase in a solvent free system: Optimization and kinetic studies

Abstract Isobutyl propionate is widely used in food and beverage industries as a rum flavor. This work presents the optimization and kinetic aspects of synthesis of isobutyl propionate by esterification of propionic acid with isobutyl alcohol using immobilized lipase Novozym ® 435 in a solvent free system (SFS). Process parameters such as reaction time, temperature, enzyme loading, speed of agitation, water concentration and acid to alcohol molar ratio were optimized to achieve maximum conversion. Higher conversion of 92.52% was obtained with the reaction conditions such as: temperature 40 °C, enzyme loading 5% w/w, acid to alcohol molar ratio 1:3, time 10 h and stirring speed of 300 rpm. The bisubstrate kinetic models of the enzyme catalyzed reactions namely Ordered Bi–Bi, Random Bi–Bi and Ping-Pong Bi–Bi were applied to determine the initial rates and correlated with the experimental findings. Ping-Pong Bi–Bi model with substrate inhibition by both acid and alcohol gives the best fit with parameter values as V max = 0.5 Mol/min/g catalyst, K A = 0.631 M, K B = 0.003 M, K iA = 0.0042 M and K iB = 0.1539 M for the concentration ranges of 2.25–10.21 M for propionic acid and 2.55–9.01 M for iso-butanol. The immobilized lipase could be reused for seven times with the % conversion of acid reaching to 83%; signifies that still it can be reused for several more times. SFS is the added benefit to produce such commercially valuable flavor ester.

Surface acidity and catalytic activity of aged /SnO2 catalyst supported with WO3

Abstract New solid acid was prepared by loading of aged 15 wt.% SO 4 2 - /SnO2 catalyst with 15 and 35 wt.% WO3. The catalysts were calcined at 400 and 650 °C. The surface areas of the catalysts were determined by the data of N2 adsorption at −196 °C. The surface acidity was measured potentiometricaly using n-butylamine solution in acetonitrile. The types of acidic sites were determined by FT-IR spectra of adsorbed pyridine. The catalytic activities of the catalysts were tested toward esterification of propionic acid (PA) with n-butanol (B). The SBET values of the ISS were decreased with an increase in the calcination temperature, whereas, the SBET of the loaded catalysts was maximum at 400 °C. The results reveal that the used catalysts possess very strong acid sites and contain both Bronsted and Lewis acidic sites. The acid strength, total surface acidity and the conversion of PA were maxima for 400 °C products. The effect of the reaction parameters was also studied, and shows that the PA conversion was increased with an increase in the reaction temperature and the catalyst weight. The reactant molar ratio shows a maximum conversion at PA:B = 1:2. The kinetics study indicates that the catalytic esterification of PA with B obey first order kinetics equation. The results were compared with previously prepared non-aged catalysts. The comparison reveals that the aging of the support would causes a decrease in SBET, acid strength and catalytic activity, but increases the acid amount of the catalyst.

High-surface-area SBA-15–SO3H with enhanced catalytic activity by the addition of poly(ethylene glycol)

The influence of poly(ethylene glycol) (PEG) and synthesis temperature in the synthesis of SBA-15–SO3H was investigated to evaluate the catalytic activity in the esterification of propionic acid with methanol. The catalysts were characterized by means of surface and structure analyses; X-ray diffraction, FT-IR, scanning electron microscopy, Thermo-gravimetric and N2 adsorption/desorption techniques. It was found that, by the addition of PEG, the surface area and porosity of SBA-15–SO3H increased, while the structure and size of mesopores remained unchanged. Nitrogen sorption measurements indicate that PEG introduces additional pores into the pore walls of SBA-15–SO3H. Thus, a simple way of improving the porosity of mesoporous SBA-15–SO3H was presented that could enhance transport of substrates through the porous system and allow the generation of stable mesoporous replicas, important for catalytic applications and also beneficial for replication and nanocasting purposes.

Preparation, characterization and catalytic activity of WO3 supported on sulfated tin oxide catalysts

Solid acid catalysts of 15wt.%SO4/SnO2 loaded with 5–45wt.%WO3 were prepared, calcined at 400–800°C, and then characterized by TG–DTA, XRD, FT-IR spectra and nitrogen adsorption techniques. The surface acidity was determined by potentiometric titration with n-butylamine in acetonitrile and FT-IR spectra of chemisorbed pyridine.The presence of sulfate ions together with WO3 hindered the crystallization of tin oxide and the products at a lower temperature of ⩽500°C found amorphous. The crystallinity of tin oxide increased with raising the calcination temperature to provide nanocrystalline cassiterite structure, whereas, increasing WO3 loading up to 25wt.% decreases the process. Careful control of calcination temperature and WO3 loading was found to have a critical effect on the specific surface area and therefore on the resulted surface acidity.The surface acidity measurements indicate that the catalysts possess very strong acid sites that designate both of Brønsted and Lewis acid sites.Catalytic application toward esterification of propionic acid with n-butanol was tested and the effect of various parameters, i.e., reaction temperature, reactant molar ratio, weight of the catalyst, WO3 loading and calcination temperature was also investigated. The highest conversion level was found for products loaded with 25wt.%WO3 and calcined at 400°C. Although both of Brønsted and Lewis acid sites are responsible for the reaction, the former acid sites found more effective on catalyzing the esterification reaction.