2-Thiophenecarboxylic acid → Acetylthiomethyltriethoxysilane

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Reaction Conditions

Reaction Steps

This example illustrates the preparation of a thiocarboxylate alkoxysilane from a salt of a thiolcarboxylic acid using a nonprotic solvent. 88 grams of powdered sodium ethoxide and 600 ml diglyme were charged into a one-liter, three-neck round bottomed flask equipped with magnetic stir bar, temperature probe/controller, heating mantle, addition funnel, condenser, N2 inlet, and ice water bath. The solution was cooled to 8° C., and 105 grams of thiolacetic acid was added slowly via the addition funnel, keeping the temperature below 60° C. The solution was allowed to cool to 35° C., and 250 grams of chloromethyltriethoxysilane was added via the addition funnel. After addition was complete, the solution was heated to 70° C., where a brief exotherm to 120° C. was observed. The solution was heated at 70° C. for an additional three hours. A white solid formed which was filtered first through a 0.1 μm pressure filter and then a 0.01 μm filter to give a clear, black solution. The solvent was removed under reduced pressure, and the remaining liquid vacuum distilled to yield 163 grams of a clear and colorless liquid, a 55 percent yield.

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