Biodiesel is gaining more and more importance as an attractive fuel due to the depleting fossil fuel resources. Chemically biodiesel is monoalkyl esters of long chain fatty acids derived from renewable feed stock like vegetable oils and animal fats. It is produced by transesterification in which, oil or fat is reacted with a monohydric alcohol in presence of a catalyst. The process of transesterification is affected by the mode of reaction condition, molar ratio of alcohol to oil, type of alcohol, type and amount of catalysts, reaction time and temperature and purity of reactants. In the present paper various methods of preparation of biodiesel with different combination of oil and catalysts have been described. The technical tools and processes for monitoring the transesterification reactions like TLC, GC, HPLC, GPC, 1H NMR and NIR have also been summarized. In addition, fuel properties and specifications provided by different countries are discussed.

Technical aspects of biodiesel production by transesterification—a review

Various novel techniques including ultrasound-assisted extraction, microwave-assisted extraction, supercritical fluid extraction, and accelerated solvent extraction have been developed for the extraction of nutraceuticals from plants in order to shorten the extraction time, decrease the solvent consumption, increase the extraction yield, and enhance the quality of extracts. A critical review was conducted to introduce and compare the conventional Soxhlet extraction and the new alternative methods used for the extraction of nutraceuticals from plants. The practical issues of each extraction method were discussed. Potential uses of those methods for the extraction of nutraceuticals from plant materials was finally summarized.

Recent advances in extraction of nutraceuticals from plants

http://irep.iium.edu.my/28632/4/Santanu_J_Food_Eng%2D2013.pdf

Techniques for extraction of bioactive compounds from plant materials: A review

Furfural offers a promising, rich platform for lignocellulosic biofuels. These include methylfuran and methyltetrahydrofuran, valerate esters, ethylfurfuryl and ethyltetrahydrofurfuryl ethers as well as various C(10)-C(15) coupling products. The various production routes are critically reviewed, and the needs for improvements are identified. Their relative industrial potential is analysed by defining an investment index and CO(2) emissions as well as determining the fuel properties for the resulting products. Finally, the most promising candidate, 2-methylfuran, was subjected to a road trial of 90,000 km in a gasoline blend. Importantly, the potential of the furfural platform relies heavily on the cost-competitive production of furfural from lignocellulosic feedstock. Conventional standalone and emerging coproduct processes-for example, as a coproduct of cellulosic ethanol, levulinic acid or hydroxymethyl furfural-are expensive and energetically demanding. Challenges and areas that need improvement are highlighted. In addition to providing a critical review of the literature, this paper also presents new results and analysis in this area.

Furfural—A Promising Platform for Lignocellulosic Biofuels

Transesterification of soybean oil with methanol was investigated. Three stepwise and reversible reactions are believed to occur. The effect of variations in mixing intensity (Reynolds number=3,100 to 12,400) and temperature (30 to 70°C) on the rate of reaction were studied while the molar ratio of alcohol to triglycerol (6:1) and the concentration of catalyst (0.20 wt% based on soybean oil) were held constant. The variations in mixing intensity appear to effect the reaction parallel to the variations in temperature. A reaction mechanism consisting of an initial mass transfer-controlled region followed by a kinetically controlled region is proposed. The experimental data for the latter region appear to be a good fit into a second-order kinetic mechanism. The reaction rate constants and the activation energies were determined for all the forward and reverse reactions.

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Kinetics of transesterification of soybean oil

Supercritical fluids have a great potential for wide fields of processes. Extraction processes with supercritical fluids are established even in industrial scale and become again more interesting for industry. Beside this, developments like fractionation of products, dyeing of fibres, treatment of contaminated soils, production of powders in micron and submicron range and reactions in or with supercritical fluids are only a rough extract of possible investigations which will be covered in this paper.

Use of supercritical fluids for different processes including new developments—a review

Emulsion liquid membrane processes are discussed. The characteristics of the processes, research activities and commercial applications are surveyed and the advantages and disadvantages are outlined. The first large-scale plant for the separation of zinc is described as well as several pilot plants for the separation of various metals from aqueous solutions.

Emulsion liquid membranes part I: Phenomenon and industrial application

Separation of metal species by emulsion liquid membranes

New approach in the modelling of the extraction equilibrium of zinc with bis-(2-ethylhexyl) phosphoric acid

The acceptance of methylesters (biodiesel) as an alternative fuel has rapidly increased in recent years. This development has been followed by increasing research activities in the field of methylester processes. After listing reasons that supporte arguments for biodiesel and a survey of production methods, a low-waste process for biodiesel is introduced.

Rolf Marr

Papers

Use of supercritical fluids for different processes including new developments—a review

Emulsion liquid membranes part I: Phenomenon and industrial application

Separation of metal species by emulsion liquid membranes

New approach in the modelling of the extraction equilibrium of zinc with bis-(2-ethylhexyl) phosphoric acid

A low-waste process for the production of biodiesel