Synthesis of oxymethylene ethers with 2-ethylhexyl terminal groups
摘要
Oxymethylene ethers are considered for use as components of fuels and lubricants. They can be obtained from renewable raw materials, and their properties can be tailored by modifying the structure of the terminal alkyl groups. This paper presents the results of a study on the synthesis of oxymethylene ethers from 2-ethylhexanol and paraformaldehyde. High efficiency in the synthesis has been demonstrated by shifting the thermodynamic equilibrium through azeotropic distillation of water formed during the reaction. The process achieves a high alcohol conversion rate (up to 95%), with near-100% selectivity toward the target ethers. The formation of oxymethylene ether from high molecular weight alcohols is more sensitive to water than light alcohols. Under similar conditions, water reduces the methanol conversion to oxymethylene ethers by half, while the reaction with 2-ethylhexanol is almost completely suppressed. It has been shown that oxymethylene ethers with 2-ethylhexyl terminal groups are suitable as components of specialty lubricants due to their excellent low-temperature properties, resistance to hydrolysis, and viscosity dependence on the molecular weight distribution.
Graphical abstract