Synthesis Of Glycerol Monoethers-the Method To Converse The Byproduct Of Biodiesel Procedure To High Value-added Products

Nowadays human beings start to seek new clean energy to replace the traditional energy, due to the shortage of oil reverse, the increase of oil price and the threat of greenhouse gas to environment. Biodiesel is one of most promising renewable energy. As the biodiesel is used widely recently, the output of process byproduct glycerol increases sharply, which already exceed the market demand. How to consume the excess of glycerol or converse glycerol to more value added products become a hot spot for chemists. Glycreol monoether is not only a kind of great surfactant, but also has good bioactivities, such as antibacteria and anti-allergy, it is one of the most value added glycerol derivative with a lot of potential applications. Since glycerol has three hydroxyl groups with similar chemical activities, the control of the regioselectivity is difficult. Traditional procedure to synthesize glycerol monoether involves multi-step with Williamsom etherification, which means high cost and large amout of waste, it is not good for large-scale production. To seek for new methods to converse glycerol to glcyerol monoether, in this work, we tried to employ different reducing systems to prepare glycerol monoethers and developped a new method to synthesize glycerol monoethers in one step directly from glycerol which is simply and practicable, the catalyst in the method is easy to be separated from the reaction and can be reused, there are no useless salts generated during the reaction. All these advantages accord with the principle of green chemistry.1. Developping the etherification between aldehyde/ketone and alcohol under hydrogen pressure with Pd/C as catalyst, we found glycerol reacted with aldehyde/ketone to form glycerol monoether in one step. After the optimization of different factors, the yield of etherification was improved to a high level, and the selectivity to a-alkyl glycerol monoether is quite high.2. Using the cheaper starting material methyl ester to replace the aldehyde/ketone, we found the new method to converse the ester to ether. According to the research pressure is one of most improtant factor for this reaction. At higher pressure, good yield was obtained.3. Different reducing agents were studied, such as TMDS, PHMS and HCOONH4, to converse the acetals to ether. With TMDS-Pd/C-CSA reducing system the acetals can be reduced to relative ether effectively. With this method to synthesize glycerol monoether from glycerol acetal, the products can be obtain in high yields but the selectivity to a-alkyl glycerol monoether was not as good as reaction between glycerol and aldehyde/ketone.4. Surface tension test has been performed with the glycerol monoethers which were perpared in former work. The glycerol monoethers are good nonionic surfactant which possess low CMC and lead the surface tension to 23-29 mN/m. Binary diagrams have been drawn and observation of phase change under the electron microscope have been done for perparation of ternary diagram.