Ethyl lactate production via esterification of lactic acid with ethanol combined with pervaporation (original) (raw)
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Separation and Purification Technology, 2008
Pervaporation experiments were performed for some binary mixtures involved in the esterification of lactic acid with ethanol: water/ethanol, water/ethyl lactate and water/lactic acid. The effects of feed composition and operating temperature on the membrane performance were analyzed. Two different commercial hydrophilic membranes PERVAP ® 2216 and PERVAP ® 2201 were tested for the system water/ethanol. PERVAP ® 2201 membrane was chosen for further experiments due to its better selectivity towards water. The permeation flux, as well as permeances, was found to increase with water feed concentration. The influence of temperature on the permeation flux can be described by an Arrhenius-type expression. However, not a great influence of temperature on the permeance was found. Separation factor and selectivity were found to depend on water feed concentration but not a clear influence of temperature was found on these two parameters.
Journal of Membrane Science, 2009
Pervaporation of the quaternary mixture involved in the synthesis of ethyl lactate, water/ethanol/ethyl lactate/lactic acid, has been investigated. Pervaporation experiments were performed with the commercial hydrophilic membrane PERVAP ® 2201 at 327.15 and 348.15 K. PERVAP ® 2201 membrane was previously tested for some of the binary mixtures present in the quaternary mixture showing high water selectivity. The effects of pervaporation temperature and water and lactic acid feed concentration on pervaporation performance have been studied in terms of permeation flux and permeance. The concentration range covered in this work was 12-63 wt% for water and 9-30 wt% for lactic acid. The permeation flux was found to increase with water feed concentration and temperature. However, the permeation flux was nearly constant when varying lactic acid concentration in the feed. Water permeance increased with water feed concentration but a slight dependence on temperature was observed.
Batch and continuous studies for ethyl lactate synthesis in a pervaporation membrane reactor
Journal of Membrane Science, 2010
Pervaporation process using commercial silica water selective membranes was evaluated to contribute for the ethyl lactate process intensification by continuous pervaporation membrane reactor. Preliminary studies were performed in order to assess the existence of membrane defects and mass transfer limitations, studying the influence of feed pressure and flowrate, respectively. After, in the absence of mass transfer limitations, membrane performance was evaluated experimentally, at different composition and temperature measuring the flux and selectivity of each species in binary mixtures (water/ethanol, water/ethyl lactate and water/lactic acid). Thus, species permeances were obtained for each experiment and correlated in order to account for the effect of temperature and feed composition. Permeances of ethanol and ethyl lactate depend solely on the temperature, following an Arrhenius equation; for water, its permeance follows a modified Arrhenius equation taking into account also the dependence on the feed water content. Mathematical models, considering concentration and temperature polarization, and nonisothermal effects as well, were developed and applied to analyze the performance of batch pervaporation and continuous pervaporation membrane reactor, in both isothermal and non-isothermal conditions. The PVMR with five membranes in series, operating at 70 • C, leads to 98% of lactic acid conversion and 96% of ethyl lactate purity. .pt (V.M.T.M. Silva). side. The partitioning and desorption steps are normally neglected and the remaining steps are considered as the main contributions to the overall resistance to mass transfer. The mass transfer resistance in membranes depends on its properties and also on the chemical and physical properties of the feed components. In the past, the membrane materials and dimensions were not optimized and, therefore, high membrane mass transfer resistance was commonly observed. However, new developments in membrane materials and ultra-thin composite membranes have led to much smaller membrane mass transfer resistances, which are now mainly due to the diffusive transport at the boundary layer, like noticed in the removal of volatile organic compounds from wastewaters and in the dehydration of cyclohexane . Diffusive transport depends on the hydrodynamic conditions, solute and fluid physical properties, and the system geometry. Several correlations based on the Sherwood number for calculating the mass transfer coefficient for transport in the boundary layer (K bl ) have been proposed over the years for different membrane modules configurations . Pervaporation is not usually an isothermal process; and temperature drop in the feed is frequently observed due to species vaporization. The heat transfer in pervaporation involves: (i) heat transfer from the feed bulk to the feed membrane interface; (ii) 0376-7388/$ -see front matter
Procedia Engineering, 2013
Pervaporation in recent years has received strong attention from industry as a novel, energy-efficient and environmentalfriendly separation technology.Pervaporation reactor is a new technology to enhance conversion in reversible esterification reactions. In present work, polyvinyl alcohol-polyether sulfone (PVA-PES) composite hydrophilic membrane was used for pervaporation-assisted esterification of lactic acid with iso-propanol. Experimental work of esterification of lactic acid with iso-propanol coupled with pervaporation was carried out. Effect of various parameters, such as, initial mole ratio of iso-propanol over lactic acid, the ratio of the effective membrane area over the volume of reacting mixture, process temperature and catalyst concentration on the performance of pervaporation reactor were discussed.The presented data can be extended for study and design of pervaporation reactor for similar kind of reactions.
Chemical Engineering Journal, 2007
The esterification of lactic acid with ethanol and the hydrolysis of the corresponding ester, ethyl lactate, have been studied in the presence of the commercial cation-exchange resin Amberlyst 15. The influence of different operating parameters such as stirrer speed, catalyst particle size, initial reactant molar ratio, reaction temperature and catalyst loading, has been examined. Additionally, the adsorption constants for the four components on Amberlyst 15 were determined by performing adsorption experiments between two non-reacting species. The values found for the adsorption constants follow the order: water > ethanol > lactic acid > ethyl lactate. Experimental kinetic data of the esterification and the hydrolysis reactions were correlated simultaneously with the Langmuir-Hinshelwood (LH) and pseudo-homogeneous (PH) models. The activity coefficients were calculated according to the UNIQUAC model. The LH model gave the best agreement with the kinetic experimental data. The activation energy of esterification and hydrolysis reactions were found to be 52.29 and 56.05 kJ mol −1 , respectively.
2015
Organic esters are an important class of chemicals and have shown a wide range of applications in different areas including perfumes, pharmaceuticals, flavours and chemicals intermediates [1],[2]. Besides the numerous applications, esters from nonedible crops and alternative sources are potential candidates in carbon emission reduction. In other to ascertain the future energy supplies and offset the environmental impact, low-carbon technologies will play a major role with this regards. In addition to the energy efficiency, different types of renewable energy, nuclear power, carbon capture/storage as well as new technologies must be widely developed in other to reach the emission targets. Esterification reactions can be performed in the absence of catalyst even though the reaction are in worst cases very slow due to the fact that the reaction rate depends on the autoprotolysis (transfer of proton) of the carboxylic acid group [3]. Generally, esterification does not reach completion a...
Process Intensification for Ethyl Lactate Production Using Reactive Distillation
Ethyl lactate is an important organic ester, which is biodegradable and can be used as food additive, perfumery, flavor chemicals and can effectively replace toxic and halogenated solvents for a wide range of industrial applications. In this work the simulation of the intensified process for ethyl lactate production by esterification of lactic acid with ethanol using a reactive distillation system was investigated. The intensified process includes the fermentation for the lactic acid production from sucrose and, reactive distillation process for ethyl lactate production by lactic acid esterification. A NRTL model parameter set has been established to predict the composition and temperatures for the system components. The simulation was carried out with the aid of the Aspen Plus (TM) process simulator. The results showed that the process intensification proposed in this work, based on fully renewable raw material, provides great opportunities to achieve higher conversion and improve ...
Industrial & Engineering Chemistry Research, 2008
The heterogeneous catalysis of lactic acid (88 wt %) esterification with ethanol in the presence of Amberlyst 15-wet was studied for catalyst loading of 1.2-3.9 wt %, initial molar ratio of reactants of 1.1-2.8, and temperature from 50 to 90°C. In this work a methodology based on the UNIQUAC model was developed to determine the thermodynamic equilibrium constant since in the literature there is inconsistency concerning the temperature dependence of the thermodynamic equilibrium constant. A simplified Langmuir-Hinshelwood kinetic model was used to predict the experimental data. The proposed rate law is r) k c (a Eth a Laa EL a W / K)/(1 + K Eth a Eth + K W a W) 2 ; the kinetic parameters are the preexponential factor, k c,0) 2.70 × 10 7 mol‚g-1 ‚min-1 , and the activation energy, E a) 49.98 kJ/mol. The equilibrium reaction constant is K) 19.35 exp(-515.13/T (K)) with reaction enthalpy 4.28 kJ/mol. The model reasonably predicts the kinetic experimental data, and it will be very useful to apply to the design and optimization of industrial hybrid reactive separation processes.
Open Research Europe, 2021
Background: Ethyl lactate is an environmentally benign solvent, which could substitute petrol-based volatile organic compounds (VOCs) in many applications if production costs are reduced. It is usually produced by the esterification of lactic acid with ethanol – two important chemical building blocks of biorefineries that are available at industrial scale. Reactive distillation is a promising alternative production process, which utilises process intensification to increase energy efficiency and space-time yield by enhancing the reaction kinetics. Methods: In this work, process intensification of ethyl lactate production by means of distillation was analysed with special focus on the efficient separation of water. Different setups were evaluated. The feedstock requirements were studied and the process was optimized regarding reaction kinetics in experiments on laboratory level. The preparation of anhydrous starting mixtures for ethyl lactate formation was tested in batch experiments...
Indian Journal of Chemical Technology, 2007
Crosslinked poly (vinyl alcohol) (PVA) membranes were prepared using maleic acid (MA) and citric acid (CA) as crosslinking agents. First the water separation ability of the crosslinked membranes from aqueous acetic acid (10-90% acetic acid) and ethanol (20-80% ethanol) solutions at 30 to 90°C was tested by pervaporation. The effects of temperature, feed concentration, crosslinker type on pervaporation characteristics were investigated. The PVAMA membrane showed separation factors of 1.9-16.2 and fluxes of 4.26-38.48 kg/m 2 h and PVACA membrane showed separation factors of 3.8-33 and fluxes of 2.17-480.8 kg/m 2 h for acetic acid-water separation. In case of ethanol-water separation, the PVAMA membrane showed separation factors of 0.7-17.9 and fluxes of 2.5-36.2 kg/m 2 h and PVACA membrane showed separation factors of 1.4-41.9 and fluxes of 3.8-359.7 kg/m 2 h. PVACA membrane has shown high separation efficiency of water than that of PVAMA membrane. Having high selectivity and good per...