The search for new applications of glycerol, as a chemical platform from which a broad spectrum of new valuable derivatives can be obtained, is ongoing. In the present communication, a new mechano-chemical reactor is used for the valorisation of glycerol, and some examples of potential chemical processes by using mechano-chemical energy will be provided in order to reduce the residence time, to minimize the use of solvents or to decrease the temperature.
In this sense, the mechano-chemical synthesis of calcium diglyceroxide from glycerol and CaO has been optimised. Finally, a new and more efficient mechano-chemical synthesis of CaDG has been achieved, requiring short synthesis time without heating and no need of solvents. The stability of this catalyst is studied under presence of free fatty acids and water, compounds presents in waste oils that decrease the yield to fatty acid methyl ester (FAME) during the reaction. Moreover, the transesterification reaction of used and refined vegetable oils with methanol has also been studied and optimised in the presence of CaDG as basic solid catalyst, using the same mechano-chemical reactor that promotes the oil-methanol mixing, minimizing the mass transfer problems associated to the immiscibility of reactants. Low methanol:oil ratios and low temperature can be used with promising results using a mechanical reactor even with used oils and in plant pilot scale under flow conditions.
Glycerol carbonate is a green chemical glycerol derivative with several industrial applications (solvents, pharmaceutics, detergent, adhesives, lubricants, beauty, among others). Preliminary tests using a mechano-chemical reactor under continuous flow conditions shows the possibility to reduce the time of reaction to 1h and lowering the temperature. Finally, the production of Zn glycerolate (good candidate for the tire industry) is also studied.
