Optimization of Solketalacetin Synthesis as a Green Fuel Additive from Ketalization of Monoacetin with Acetone

Abstract

An economical and easy to scale up method for glycerol conversion to solketalacetin (i.e., (2,2-dimethyl-1,3-dioxolan-4-yl)methyl acetate) as a valuable fuel additive is described, for the first time. Monoacetin was synthesized by reacting glycerol with acetic acid, and then solketalacetin was produced from the reaction of monoacetin with acetone using Purolite PD 206 as a catalyst. The central composite design was employed for the experimental design and then response surface methodology was used for the optimization of variables for the second stage of the reaction. The optimum operating conditions for the second stage of the reaction were as follows: acetone to monoacetin mole ratio, 5; reaction temperature, 20 °C; pressure, 45 bar; flow rate, 0.2 mL•min −1 ; and catalyst, 2.0 g. Yield of the second stage of the reaction at the experimental design conditions and at the acetone to monoacetin mole ratio of 9 was obtained as 69% and 100%, respectively.

Continuous Synthesis of a Green Fuel Additive Mixture with Highest Quantities of Solketalacetin and Solketal and Lowest Amount of Diacetin from Biodiesel-Derived Glycerol

“…22 Ketalization of the solution in stage 1 was conducted under these optimum conditions to obtain a mixture with the following mole percentage: solketalacetin = 62%, solketal = 30%, and diacetin = 8% with no byproducts. Figure S4 (SI section) presents the GC-FID chromatogram of the final solution.…”

“…23 These concerns have led us to the conclusion that the final mixture in our previous work, due to its high diacetin content (31%), lack the expected properties to use it as a desirable fuel additive. Therefore, for the sake of scaling up our previous project, we decided to improve the production procedure to increase the mole percentage Gorji and Ghaziaskar 1219 Vol. 29, No.…”

“…They indicated that solketalacetin is a better viscosity improver and does not increase the density as much as triacetin. In our previous work, 22 a novel method was developed for the synthesis of solketalacetin consisting of two stages. In the first stage, a mixture was obtained from the reaction of glycerol and acetic acid in a batch system with the mole percentage of 60, 31, 4 and 5%, for monoacetin, diacetin, triacetin, and the residual glycerol, respectively.…”

“…Reaction of glycerol with acetic acid is a consecutive one. 25 Increasing Gorji and Ghaziaskar 1221 Vol. 29, No.…”

“…In the second stage of the process, the mixture of monoacetin (62%), glycerol (30%) and 8% diacetin was reacted with acetone under the optimum conditions. 22 Finally, a suitable mixture as biofuel additive was obtained with the mole percentage values of solketalacetin, solketal, and diacetin as 62, 30, and 8%, respectively. …”