Synthesis of Dipentaerythritol from Pentaerythritol under Acidic Conditions

The direct synthesis of dipentaerythritol (DPE) from pentaerythritol (PE) was studied under acidic conditions. After optimization of the reaction parameters in a batch reactor, DPE was obtained with 50% selectivity when 50% PE was converted. This process, using PE in suspension in sulfolane (PE/sulfolane ratio = 2333 g/L) at 175 degrees C for 60 min, required a low amount of sulfuric acid (0.5 mol %). The optimized conditions were transposed to a 140 grams scale process. Finally, DPE was isolated with 16% yield (72% gas chromatography, GC purity) for 28% conversion of PE that corresponds to 57% DPE selectivity.