Diethyl dibutylmalonate can be used to prepare Guerbet acid. Guerbet acid is a fatty acid with a long branched alkane at the α position of the carboxylic acid. Compared with straight-chain fatty acids with the same carbon number, it has the characteristics of being colorless and odorless, having almost no adverse effects on the human body, having a low freezing point, and having low irritation. It is widely used in industrial lubricants, metalworking fluids, cosmetics, surfactants and additives.
Under nitrogen protection, 100 g of diethyl malonate and 300 ml of anhydrous ethanol were added to a 1000 ml three-necked round bottom flask. 40.5 g of sodium methanol was slowly added at room temperature followed by dropwise addition of 102.8 g of n-bromobutane. The reaction mixture was heated to reflux for 3 hours. Upon completion of the reaction, the reaction was cooled to room temperature, 40.5 g of sodium methanol was added again and 102.8 g of n-bromobutane was added slowly dropwise and the reaction was continued to be heated and refluxed for 3 hours. At the end of the reaction, cooled to room temperature and removed the solvent under reduced pressure. The pH of the reaction system was adjusted to 7 with 1 mol/L aqueous sulfuric acid, and the organic phase was separated and washed with appropriate amount of water. Finally, diethyl di-n-butylmalonate was purified by distillation under reduced pressure to yield 154 g (90.6% yield).
[1] Patent: CN106748724, 2017, A. Location in patent: Paragraph 0024
[2] Journal of Organic Chemistry, 1995, vol. 60, # 20, p. 6379 - 6388
[3] Journal of the Chemical Society, Dalton Transactions: Inorganic Chemistry (1972-1999), 1992, # 18, p. 2679 - 2684
