In this issue
In this issue
How to improve biodiesel?
Due to its uniform chemical composition, unaltered biodiesel has a rather sharp boiling behavior. However, fuels with steadily increasing boiling curve, such as diesel fuels, show better ignition and combustion in the cylinder of the engine. In this paper [55–62], canola based biodiesel was synthetically modified via self- and cross-metathesis with 1-hexene to improve its boiling curve. The cross-metathesis reaction produced compounds with shorter chains, resulting in biodiesel with good distribution of low to high molecular weight compounds and an almost steadily increasing distillation curve. In addition, several ruthenium zeolite catalysts effectively catalyzing the reactions were identified in this work.
Montenegro, M.E. and Meier, M.A.R. Lowering the boiling point curve of biodiesel by cross-metathesis. Eur. J. Lipid Sci. Technol. 2012, 114, 55–62
Two-step synthesis of bio-based building blocks of polyurethanes
A simple synthetic route towards a new class of renewable polyols from a vegetable oil is described [84–91]. Methyl esters of rapeseed oil were transesterified with ethylene glycol followed by a photoaddition of 2-mercaptoethanol to double bonds, yielding pseudo-telechelic polyols with an average functionality of 2 or slightly above. Polyaddition of these diols with methylene diphenyl-4,4′-diisocyanate yielded a polyurethane material with thermal properties similar to the properties of a polyurethane derived from a commercial polyol.
Desroches, M. et al. Synthesis of pseudo-telechelic diols by transesterification and thiol-ene coupling. Eur. J. Lipid Sci. Technol. 2012, 114, 84–91
Bio-based replacement for phthalate plasticizers
Plasticizers are incorporated into materials to increase the flexibility, workability, or fluidity. Phthalates are commonly used plasticizers, but their use has been declining in recent years due to health concerns. Here the preparation of several bio-based plasticizer compounds is described [49–54]. The starting materials were calendula and tung oils and methyl oleate. Diels-Alder and ene adducts were synthesized by environmentally friendly solvent-free reactions and the adducts were converted by ring-opening reactions with alcohols to obtain the corresponding tricarboxylic acid triesters. Especially saturated and monounsaturated triesters with methyl ester functionalities have excellent plasticizing properties and show promise as a potential replacement for phthalate plasticizers.
Biermann, U. et al. Esters of maleinized fatty compounds as plasticizers. Eur. J. Lipid Sci. Technol. 2012, 114, 49–54