Use of green solvents derived from sugarcane in the extraction of lipids and application in the production of biodiesel and synthesis of 2-methyltetrahydrofuran through bagasse

Abstract

Solvents are used in chemical processes to aid in mass and heat transfer, and to facilitate separations and purifications. They are also an important and often the primary component in cleaning agents, adhesives and coatings (paints, varnishes and stains). Solvents are often volatile organic compounds (VOCs) and are therefore a major environmental concern as they are able to form low level ozone and smog through free radical air oxidation processes. Currently million tons of toxic solvents are used in the oil extraction industry, in which we can mention the n-hexane, representing a major environmental problem. Many solvents can be obtained from renewable feed stocks and can be used as 'slot-in' alternatives for current VOCs without any need for modification of equipment or procedure. Green chemistry was coined to encourage the design of products and processes that minimize environmental impact. Brazil is the world's largest producer of sugarcane and its residue can be a valuable source of raw material for the production of green solvents. Among these solvents we can mention 2-methyltetrahydrofuran can be obtained from the sugarcane bagasse and isoamyl alcohol that is a residue from the distillation of alcohol. One application of the use of solvents refers to the extraction process. The most common and effective methods for extracting oil from wet materials include those developed by Folch (1957) and Bligh and Dyer (1959) which utilize biphasic systems of the nonpolar organic solvent chloroform and the polar solvents methanol and water. The objective of this project is to select a green solvent system with similar extraction efficiencies as the traditional Bligh and Dyer method. With the experimental protocol developed and the best solvent ratio (2-MeTHF:isoamyl alcohol:water), it is applied in the biodiesel production process by in situ transesterification using the microalgae Chlorella pyrenoidosa. Transesterification occurs at ambient pressure and supercritical conditions. It will also be proposed the synthesis of 2-MeTHF from sugar cane bagasse, in order to reduce the country's dependence on import of this solvent. In this work, sunflower seeds and the microalgae Chlorella pyreinodosa are used as materials for solvent extraction. In which will be analyzed the fatty acid composition and the extraction efficiency and selectivity. The process for in situ transesterification will be pressure environment and supercritical conditions; biodiesel will be analyzed for the fatty acid composition, rheology and acid value. The synthesis of 2-MeTHF carried out by acid hydrolysis of sugarcane bagasse, furfural obtained is hydrogenated to obtain the solvent. Spectrometric analysis of the infrared (IR) and Nuclear Magnetic Resonance (NMR 1H and 13C) are used. The yield of the process will also be evaluated. (AU)