Green Synthesis of Double Long-Chain Diglycerol Diacetal and Its Application as Lubricating Base Oil

Dehydration acetalization of diglycerol with lauraldehyde in the presence of homogeneous acid catalysts using water as solvent has been studied. The prepared double long-chain diglycerol diacetal was identified as a mixture of six regioisomers by GC and GC-MS. p -Dodecylbenzenesulfonic acid exhibited excellent activity for this acetalization reaction. The reaction parameters with p -dodecylbenzenesulfonic acid catalyst were subsequently optimized in terms of the yield and isomer distribution of diglycerol diacetal. Under the optimum operating conditions, the yield of diglycerol diacetal reached 93.9%, and the selectivity in terms of the distribution of the six regioisomers was found to be in proportions of 24:36:18:11:3:8. Furthermore, the tribological performance of diglycerol diacetal has been evaluated as a potential lubricant base oil by means of an Optimol SRV-V oscillating reciprocating friction and wear tester. The tribological test results revealed that diglycerol diacetal displayed superior lubrication properties compared to the commonly used poly-alpha-olefin (PAO 8).