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The use and production of bioalcohols, butanol and ethanol, are described in this chapter. In the first part, the state of art of their production is explained, as well as the reaction pathways, the different reaction geometries, and the importance of the sources as raw material. The possibility of using pervaporation (PV) coupled with a conversion reactor is shown. The use of two membranes in series (hydrophobic-hydrophilic) allows a high-quality product to be produced. A brief revision of the current performance of the membrane used is described, which allows us to understand the direction in which research has to go to improve this technology. A comparison of PV with current technologies used to purify these alcohols is reported as well. The current state of production for these two alcohols is illustrated, along with future perspectives.

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Separation processes are among the most energy-intensive stages in the chemical industry, and the evaluation and minimization of environmental impacts is part of the challenges faced by environmental engineering. Pressure swing distillation is a commonly used technique for separation of the mixture methanol/ tetrahydrofuran (THF); the separation is not feasible with conventional distillation due to the presence of an azeotrope. In this work, the design of a hybrid process consisting of distillation and pervaporation is elaborated as an alternative for the separation and evaluated from a technical and an environmental point of view. Three different compositions of the feed stream are considered: 25, 50 and 75 wt% methanol in THF and the simulation of pressure swing distillation and the hybrid process allows comparison of the energy requirements. In addition, the effect of the membrane performance on the purity of the products and the energy demand were studied. Life cycle assessment (LCA) was used to evaluate the environmental impact of both alternatives compared to incineration. From the LCA, it was observed that the hybrid process produces the lowest impact, indicating that solvent recovery is a key issue to minimize the environmental burdens. Thus, integration of membrane technology in a hybrid configuration should be considered in the design and development of more environmentally friendly processes.

Purpose: The goal and scope of this research is focused on the application of life cycle assessment (LCA) to evaluate two alternatives (batch and continuous distillation and incineration with energy recovery) for the treatment of four waste-solvent mixtures typically produced in the chemical industry: acetonitrile-toluene, acetonitrile-toluene-tetrahydrofuran (THF), ethyl acetate-water and methanol-THF, with several compositions in order to determine the most appropriate technology depending on the characteristics of the mixture. Materials and methods: Ecosolvent® v.1.0.1 software is used to perform the LCA, considering two scenarios and the following methods of impact assessment: Eco-indicator 99, cumulative energy demand, method of ecological scarcity (UBP'97), global warming potential and CO2 balances. Results and discussion: Results show that distillation gives more environmental credits for the recovery of the most concentrated compound in acetonitrile-toluene mixtures. However, when THF is present in the waste solvent even in small quantities, it has to be recovered due to the high impact associated to its manufacture. Regarding the mixture ethyl acetate-water, distillation takes advantage at concentrations of ethyl acetate higher than 50 wt%, and for the mixture methanol-THF, recovery of methanol is not advantageous from an environmental point of view, but the recovery of THF is clearly necessary to decrease the total impact. Conclusions: From this study, it can be concluded that those compounds that yield a great environmental burden during the production step should be always recovered in order to minimize the total impact, even if they represent the minor concentration in the mixture. In case that similar impact is produced during the solvent production, the major compound in the mixture should be the target for recovery. © 2012 Springer-Verlag Berlin Heidelberg.

Purpose: The goal and scope of this research is focused on the application of life cycle assessment (LCA) to evaluate two alternatives (batch and continuous distillation and incineration with energy recovery) for the treatment of four waste-solvent mixtures typically produced in the chemical industry: acetonitrile-toluene, acetonitrile-toluene-tetrahydrofuran (THF), ethyl acetate-water and methanol-THF, with several compositions in order to determine the most appropriate technology depending on the characteristics of the mixture. Materials and methods: Ecosolvent® v.1.0.1 software is used to perform the LCA, considering two scenarios and the following methods of impact assessment: Eco-indicator 99, cumulative energy demand, method of ecological scarcity (UBP'97), global warming potential and CO2 balances. Results and discussion: Results show that distillation gives more environmental credits for the recovery of the most concentrated compound in acetonitrile-toluene mixtures. However, when THF is present in the waste solvent even in small quantities, it has to be recovered due to the high impact associated to its manufacture. Regarding the mixture ethyl acetate-water, distillation takes advantage at concentrations of ethyl acetate higher than 50 wt%, and for the mixture methanol-THF, recovery of methanol is not advantageous from an environmental point of view, but the recovery of THF is clearly necessary to decrease the total impact. Conclusions: From this study, it can be concluded that those compounds that yield a great environmental burden during the production step should be always recovered in order to minimize the total impact, even if they represent the minor concentration in the mixture. In case that similar impact is produced during the solvent production, the major compound in the mixture should be the target for recovery. © 2012 Springer-Verlag Berlin Heidelberg.