Viviana M. T. M. Silva

Ethyl lactate as a solvent: Properties, applications and production processes – a review

Ethyl lactate is an environmentally benign solvent with effectiveness comparable to petroleum-based solvents. The worldwide solvent market is about 30 million pounds per year, where ethyl lactate can have an important share. It is considered a chemical commodity and has attracted much attention in recent years, since it is formed by the esterification reaction of ethanol and lactic acid, which can be generated from biomass raw materials through fermentation. In this work, an overview regarding the main properties and applications of ethyl lactate, as well as its synthesis and production processes, with a particular emphasis on reactive/separation processes, is presented.

Adsorption of propane and propylene onto carbon molecular sieve

Abstract Equilibrium data for propane and propylene adsorption on a carbon molecular sieve (CMS) 4A from Takeda are presented in the temperature range 343–423 K and 0–300 kPa pressure. The pellet adsorption loading is 0.9 mol/kg for propane and 1.2 mol/kg for propylene at 100 kPa and 373 K. The equilibrium selectivity for propylene in the low-pressure range are 2.3 (343 K) and 1.7 (423 K). Experimental data were fitted with the Toth and Dubinin models. Zero length column (ZLC) technique has been used to determine the controlling mechanism and estimate the diffusivity parameters. Transport of both hydrocarbons in the pellets is controlled by micropore diffusion. Breakthrough curves were measured in the same temperature range and atmospheric pressure, at the low partial pressure of adsorbate (linear region of the isotherm). Simple models have been used in the simulation of breakthrough curves.

Synthesis of diethylacetal: thermodynamic and kinetic studies

The synthesis of diethylacetal was studied in a batch reactor by reacting ethanol and acetaldehyde in the liquid phase, using the acid resin Amberlyst 18 as catalyst. The reaction equilibrium constant was determined experimentally in the temperature range 293-333 K at 1.0 MPa: K eq =0.018exp(1230/T). The standard molar reaction properties were obtained at 298 K: ΔH 0 =-10225.9 J/mol, ΔG 0 =-269.3 J/mol and ΔS 0 =-33.395 J/mol.K. The standard molar properties of formation of acetal in the liquid phase at 298 K were estimated: ΔH f 0 =-476.18 kJ/mol, ΔG f 0 =-239.42 kJ/mol and S f 0 =291.3 J/mol.K. Kinetic experiments were carried out in the temperature range 289-299 K at 0.6 MPa. A two-parameter model based on a Langmuir-Hinshelwood rate expression, using activity coefficients from the UNIFAC method, can describe the experimental kinetic results. The proposed kinetic law is r=k C (a A a B -a C a D /(K eq a A ))/(1+K I2 a C /a A ) 2 , and the parameters are k C =1.16x10 8 exp(-5758.2/T(K)) mol/g.min and K I2 =5.66x10 3 exp(-2206.4/T(K)). The activation energy of reaction is 47.874 kJ/mol.

Fixed Bed Adsorptive Reactor for Ethyl Lactate Synthesis: Experiments, Modelling, and Simulation

Abstract Multicomponent adsorption equilibrium data were measured through binary adsorption experiments performed in a fixed bed column packed with Amberlyst 15-wet for the ethyl lactate system, at 20°C and 50°C. A novel approach based on the multicomponent Langmuir isotherm was used assuming a constant monolayer capacity in terms of volume for all species, reducing the adjustable parameters from 8 to 5, for each temperature. Reactive adsorption experiments were performed and used to validate a mathematical model developed for both fixed bed and simulated moving bed reactors, which involves velocity variations due to the change of multicomponent mixture properties.

Dynamic study of the synthesis of 1,1-dibutoxyethane in a fixed-bed adsorptive reactor

The synthesis of 1,1-Dibutoxyethane in a fixed-bed adsorptive reactor using Amberlyst 15 was studied for the first time. The adsorption of non-reactive pairs was investigated experimentally, at 25°C, by frontal chromatography in a fixed-bed adsorber. In order to avoid the immiscibility of the liquid phase, the liquid-liquid equilibrium for the mixture 1-butanol/water was studied. The multicomponent equilibrium adsorption data was assumed to follow the modified Langmuir type isotherm. Reaction experiments of 1,1-Dibutoxyethane production and column regeneration were performed in the fixed-bed adsorptive reactor. This work will enable further developments in chromatographic reactors aiming at the 1,1-Dibutoxyethane process intensification.

Use of Ion Exchange Resins in Continuous Chromatography for Sugar Processing

In this chapter, the use of ion exchange resins in continuous sugar process industry is reviewed. A particular focus is given to chromatographic methods and, in particular, to continuous annular chromatography and simulated moving-bed (SMB) apparatus. The use of ion exchange resins for the separation of a fructose and glucose mixture (by means of an SMB unit) and the separation into pure components of a ternary mixture of sugars (by means of a Pseudo-SMB technique) is detailed. The use of ion exchange resins in integrated reactors (separation in situ with reaction) is also addressed in this chapter, presenting several advantages of these promising intensified processes for the sugar industry.