Acetal → 1,1,3-Triethoxy-2-methyl-butane

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900 g (7.4 mol) of acetaldehyde diethyl acetal (purity according to GC: 97%) and 0.85 g (0.75 ml, 6 mmol, 0.25 mol %) of boron trifluoride etherate were placed in a 2 l two-necked round flask fitted with a magnetic stirrer, a thermometer and a dropping funnel. 220 g (2.5 mol) of ethyl (1-propenyl) ether were added dropwise within about 30 minutes while cooling occasionally with ice at a temperature of about 35° C., but a maximum of 40° C. After completion of the addition the mixture was stirred at room temperature for a further 30 minutes. Then, 4 g of solid, powdered sodium carbonate were added thereto and the mixture was stirred at room temperature for 2.5 hours. Then the mixture was suction filtered and the excess acetaldehyde diethyl acetal was distilled off on a Raschig column, (30×2.5 cm) at 100 mbar. About 1 l of acetaldehyde diethyl acetal (content according to GC. 91%) was recovered in this manner at a boiling point of 40-43° C. The residue was then fractionated on the same column at a pressure of 12-13 mbar. This gave 344.5 g (66.2% yield) of 1,1,3-triethoxy-2-methyl-butane as a water-clear liquid with a boiling point of 81-84° C. and a content of 98.2% according to GC.

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