Reactive extraction of succinic acid from aqueous solutions using Tri-N-Octylamine (TOA) in 1-decanol: Equilibria and effect of temperature

Succinic acid is a dicarboxylic acid. Its usage has been increased as a great green feedstock for the manufacture of synthetic resins, biodegradable polymers and chemical intermediates. Production process of succinic acid by fermentation method needs an economic separation method to compete with the synthetic process and is mainly depends on downstream process because downstream purification costs usually reach 60-70% of production cost. Several possible alternatives for the recovery of succinic acid from fermentation broth exist. Among these alternatives, reactive extraction is considered as the primary separation step for the recovery of succinic acid from the fermentation broth. In the present work, the effect of temperature on the extraction of succinic acid using tri-n-octylamine (TOA) in 1-Decanol was studied. The physical and chemical experiments have been carried out at different temperatures in the range of 298-333 K. Extraction efficiency (E %) decreased with increasing temperature. The distribution coefficient (KD) increased with increasing with TOA concentration from 10 to 30%. Reactive extraction was interpreted as a result of the formation of acidamine complex with a stoichiometry of 1:1. The equilibrium complexation constant KE1, determined using loading ratio (z), found to decrease from 15.64 to 3.54 with respect to temperature from 298k to 333 K. The enthalpy (Delta H) and entropy (Delta S) of the reaction were evaluated. The Delta H value for the reactive extraction of succinic acid was determined to be -7.91 kcal mol-1 and the corresponding Delta S value was -21.43 cal mol-1 K-1. The reaction for succinic acid-TOA complex was found to be exothermic in nature

Recovery of volatile fatty acids by reactive extraction using tri-n-octylamine and tri-butyl phosphate in different solvents: Equilibrium studies, pH and temperature effect and optimization using multivariate Taguchi approach

Recovery of volatile fatty acids from fermentation broth has been investigated by adopting an intensified approach using extractants tri-n-octylamine and tri-butyl phosphate dissolved in 1-decanol and methyl isobutyl ketone. The effects on distribution coefficient (K_D) and extraction efficiency (%E) were studied by varying the operating conditions like temperature (293.15-323.15) K, pH (2.5, 3.5 and 4.5) and compositions of extractant (10, 20 and 30%).Taguchi (L_36) orthogonal design with five factors namely diluents, extractant type and composition, temperature and pH were employed for the multivariate optimization of reactive extraction of volatile fatty acids. In Taguchi approach, "Larger is better" criterion was adopted to maximize K_D and % E. The statistical analysis indicated that the degree of influence on K_D by experimental variables follows the trend: extractant type (X_2) > pH (X_5)> diluent type (X_1) > temperature (X_4) > extractant concentration (X_1). The trend for % E observed is: extractant type (X_2) > pH (X_5) >temperature (X_4) >extractant concentration (X_1) > diluent type (X_1).The combination of optimum parameters were obtained as(X1= 1-decanol, X2= tri-n-octylamine, X3= 20%, X4= 293.15 K and X5=3.5).A confirmation run was conducted using these parameters and K_D and % E values from this run were determined to be 8.65 and of 89.64%, respectively, which were very close to the predicted values 〖 K〗_D=10.36 and % E =91.26%

Parametric optimization and rate laws determination for the conversion of 4-tert-butylbenzoic acid to methyl 4-tert-butylbenzoate

289-299The esterification of 4-tert-butylbenzoic acid has been studied to produce methyl 4-tert-butylbenzoate, having its widespread applications in the pharmaceuticals, perfumes, flavor, cosmetics, and fragrance industries. The limiting nature of the reaction is catalyzed with methane sulphonic acid, a green catalyst. The study focused on optimization of the experimental parameters to achieve higher conversion of acid with the aid of statistical analysis based on the Taguchi technique. An L9 array, S/N ratios, and ANOVA have been used with catalyst concentration, molar ratio and time as the process parameters with acid conversion as the response variable. Parametric optimization based on Taguchi method suggest a combination of optimal parameters as 10% catalyst concentration, 5:1 methanol to acid molar ratio and 2 h at a refluxing temperature of 67°C. A kinetic investigation for the esterification is also conducted to define the rate equations that govern the overall progress of reaction and the results established that the reaction follows irreversible pseudo second order rate in the initial phase followed by the reversible second order rate. The proposed model is found to be in good agreement with the experimental results

Regeneration of levulinic acid from loaded-organic phase: equilibrium, kinetics and process economics

Regeneration of carboxylic acids from the loaded- organic phase is an essential step to complete the reactive extraction process. A study on the regeneration of levulinic acid from loaded-organic phase (methyl isobutyl ketone + tri-n-octylamine +acid) was carried out using various techniques including NaOH, temperature swing, diluent swing, and tri-methylamine methods. Equilibrium data obtained show that among all the methods, the recovery of acid is the highest for the tri methylamine method when the molar ratio of tri-methylamine to levulinic acid concentrations is greater than 1. Kinetic studies performed for the tri-methylamine method showed that there are no changes in the specific rate of extraction with changes in stirrer speed rate and phase volume ratio (Vaq/ Vorg), and the overall order of reaction is 1.5. Based on the effects of stirrer speed and phase volume ratio on the specific rate of extraction, the reaction was concluded to occur in the fast regime. Also, about 80% of acid was recovered by the evaporation of tri-methylamine phase at 104-140 oC. A detailed economic evaluation for the recovery of levulinic acid using reactive extraction for a feed rate of 2 m3 h-1 shows that the payback period for recovering capital investment is 0.49 years

Recovery of levulinic acid by reactive extraction using tri-n-octylamine in methyl isobutyl ketone: Equilibrium and thermodynamic studies and optimization using Taguchi multivariate approach

Recovery of levulinic acid from an aqueous solution using a tertiary amine, tri-n-octylamine (TOA), as an extractant in methyl isobutyl ketone (MIBK) was studied at different temperatures (293-333 K). The physical equilibrium studies were performed using MIBK as a diluent. Partition (P) and dimerization (D) coefficients were found to decrease noticeably with increasing temperature. The coefficient of distribution was found to be very low in physical equilibrium. Chemical equilibrium studies were conducted using various concentrations of the extractant. The highest coefficient of distribution (K D ) and efficiency of extraction (%E) were found to be 58.0 and 98.0% respectively for 0.1 kmol m -3 of levulinic acid and 0.678 kmol m -3 of TOA at 293 K. Chemical equilibrium studies showed the formation of 2:1 complex as the main mechanism in the reactive extraction. Taguchi mixed design multivariate approach (L 18 ) was used to optimize the process variables. S/N ratio (larger-is-better) criterion was adopted to maximize the perfor mance parameters. The optimum combination of variables was found to include acid concentration (X 1 ) = 0.3 kmol m -3 , TOA concentration (X 2 ) = 0.678 kmol m -3 and temperature (X 3 ) = 293 K. A confirmation run was conducted using these parameters and K D and %E values from this run were determined to be 11.83 and of 92.2%, respectively, which were very close to the predicted values of K D = 12.78 and %E = 94%

Solubility Measurement, Modeling, and Thermodynamic Functions for para-Methoxyphenylacetic Acid in Pure and Mixed Organic and Aqueous Systems

The solubility of para-methoxyphenylacetic acid in different solvents is of critical significance for the design and optimization of its purification process via crystallization. The present study illustrates new solidliquid phase equilibrium data of para-methoxy phenyl acetic acid in water, acetonitrile, propan-2-ol, morpholine, toluene, anisole, and binary (propan-2-ol + water, propan-2-ol + toluene) mixed solvents using a static analytical method from 283.15 to 323.15 K at atmospheric pressure. The highest solubility of para-methoxyphenylacetic acid was observed in propan-2-ol and lowest in water, with the maximum solubility effect for propan-2-ol + toluene binary system obtained at 0.5001 solute-free mole fraction of propan-2-ol. The modified Apelblat equation, λh (Buchowski) equation, and nonrandom two-liquid (NRTL) activity coefficient model were used to correlate the experimental solubility data in pure solvents, whereas the binary solvent systems were modeled using the vant HoffJouybanAcree, ApelblatJouybanAcree, and NRTL models, among which the NRTL model exhibited better goodness of fit. Also, for insight into the molecular interactions in the solvent systems, the enthalpy of dissolution has been being evaluated

Measurement and Modeling of Solid-Liquid Equilibria of l -Glutamic Acid in Pure Solvents and Aqueous Binary Mixtures

The experimental solubility data of l-glutamic acid in pure water, formic acid, methanol, 1-propanol, 2-propanol, acetonitrile, and binary mixtures (formic acid + water, methanol + water, 2-propanol + water, acetonitrile + water) with different compositions were carried out at temperatures ranging from (283.15 to 328.15) K by the static analytic method. The solubility measurements showed that formic acid and its aqueous mixtures recorded a higher solubility than methanol + water, 2-propanol + water, and acetonitrile + water for the same composition at each temperature. Moreover, except formic acid the addition of methanol, 2-propanol, and acetonitrile to its aqueous mixtures resulted in the decrease in solubility of l-glutamic acid. The experimental data was fitted using different thermodynamic models such as the Buchowski-Ksiazczak equation, the Van't Hoff equation, the modified Apelblat equation, and the NRTL model, and the optimum values of the regressed parameters were obtained. The modified Apelblat equation, Buchowski-Ksiazczak equation, and NRTL activity coefficient model were fitted to the pure solvents solubility data, while the modified Apelblat, modified Apelblat-Jouyban-Acree, and NRTL models were used for the binary solvent systems. The results demonstrated formic acid as a cosolvent in the dissolution of l-glutamic acid in formic acid + water binary mixtures, while others exhibited an antisolvent effect on the solubilization of l-glutamic acid in their respective aqueous mixtures