Physicochemical Properties Of Green Solvents Derived From Biomass

Green Chemistry
Cite this: DOI: 10.1039/c0gc00853b www.rsc.org/greenchem

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Physicochemical properties of green solvents derived from biomass†
Laura Lomba,a Beatriz Giner,*a Isabel Bandr´ s,b Carlos Lafuenteb and Ma Rosa Pinoa e
Received 26th November 2010, Accepted 3rd May 2011 DOI: 10.1039/c0gc00853b
Downloaded by University of Bradford on 21July 2011 Published on 17 June 2011 on http://pubs.rsc.org | doi:10.1039/C0GC00853B

Several thermophysical properties (density, refractive index, speed of sound, surface tension, dynamic viscosity, static permittivity and vapour pressure) of five compounds classified as green solvents derived from biomass (furfural, furfuryl alcohol, levulinic acid, ethyl levulinate, butyl levulinate) have beenobtained from 278.15 K to 338.15 K. A comparative study has been carried out and information regarding molecular interactions and structure has been obtained.

Introduction
Several chemical or physical processes such as separation, reaction rates, mass and energy transfer or crystallization can be performed in the gaseous, liquid or solid state. However, the vast majority of these processes arecarried out in the liquid phase or in solution due to the advantages of using solvents. Solvents allow the formation of homogeneous dispersions, along with making the mass and energy transport processes easier. They also modify reactivity and allow for the deposition of solids. It is obvious that the use of solvents is fundamental to the chemical industry, as their advantages are so many and sogreat that it would be difficult to remove them from the industrial processes. The use of traditional solvents in the chemical industry produces well-known environmental problems from the consumption of unsustainable raw materials which cause the emergence of harmful derived chemical compounds that can be released to the environment. For these reasons, it is fundamental that new chemical processesbe proposed, based on the Green Chemistry principles of Anastas and Warner,1 which minimise the environmental impact of industrial processes. These principles can be seen as a compulsory handbook for all scientists when preparing their experiments and designing new compounds or working procedures. One of the bases of green chemistry is the elimination or replacement of hazardous products andreagents, inefficient processes and unsustainable raw materials. For this reason, the research and use of so-called green solvents is increasing rapidly. In relation to raw materials, a large amount of the resources come from fossil reserves such as coal, natural gas or petroleum. The main problems of using these fossil resources are that
a Facultad de Ciencias de la Salud, Universidad San Jorge,Villanueva de G´ llego, 50830, Zaragoza, Spain. E-mail: bginer@usj.es; Tel: 34 976 a 060100 b Departamento Qu´mica Org´ nica-Qu´mica F´sica, Facultad de Ciencias, ı a ı ı Universidad de Zaragoza, 50009, Zaragoza, Spain † Electronic supplementary information (ESI) available. See DOI: 10.1039/c0gc00853b

they are not renewable and their availability is diminishing rapidly. Solvents from sustainablesources including those from biomass, which are usually obtained by fermentation, enzymatic or esterification processes, are one of the new family of solvents classified as green that can be used for a number of industrial processes. In this category, low molecular weight alcohols, glycols and glycol ethers, lactates and derivatives, terpenes, furfural, levulinic acid or fatty acid esters are included.These solvents have suddenly emerged in the field of science and industrial processes and provide new options in the search for, and development of, further applications in different areas. For instance, ethyl lactate from bio-refineries is now used in the paint industry, in some processes replacing solvents such as N-methylpyrrolidone, xylene, toluene, acetone and various halogenated chemicals.2...