n-Butyl n-Butyrate (CAS NO.: ), which is also known as , butyl ester, could be produced through the following synthetic routes.

In a 2-l. flask fitted with a mechanical stirrer, a thermometer, and a separatory funnel, are placed a cool solution of 240 cc. (4.3 moles) of commercial sulfuric acid (sp. gr. 1.84) in 240 cc. of water, and 240 g. (296 cc., 3.24 moles) of technical n-butyl alcohol. The whole is placed in a large, efficient ice-salt bath.

A solution of 320 g. (1.07 moles) of crystalline sodium dichromate (350 g. of the ordinary moist technical hydrated salt is also suitable) in 200 cc. of water is dropped from the funnel into the vigorously stirred alcohol mixture as rapidly as can be done without running the temperature above 20°. When most of the dichromate has been added, the viscosity of the reaction mixture becomes so great that the stirring is rendered inefficient. The temperature is now allowed to rise to 35° if necessary , to accelerate the reaction.

The resulting green sirupy emulsion is diluted with an equal volume of water, whereupon 220–225 cc. of an oil containing the desired ester, slowly separates. This oil is washed three times with water, separated, and treated with a few grams of anhydrous sodium sulfate in order to remove most of the water. It is now distilled slowly through a large, efficient fractionating column. The fraction boiling at 150–170° is collected, and should amount to 170–175 cc. It is washed with five 15-cc. portions of 60 per cent sulfuric acid (sp. gr. about 1.5), is then washed free of acids with dilute sodium hydroxide, and finally washed free of alkali with cold water. It is rapidly dried, as before, with sodium sulfate, and fractionated through the same distilling column. The fraction boiling at 162–166° (uncorr.) consists of n-butyl n-butyrate, containing a small percentage of residual butyl alcohol. The yield is 96–110 g. (41–47 per cent of the theoretical amount).

If higher purity is desired, the fractionation must be repeated. An additional yield may be secured by further fractionation of the lower-boiling fractions.