Synthesis of Dipentaerythritol from Pentaerythritol under Acidic Conditions

Abstract

Dipentaerythritol (DPE) has been prepared from a slurry of Pentaerythritol (PE) in sulfolane catalyzed by a low amount of sulfuric acid and was isolated with 16% yield (72% GPC purity) and 57% isolated selectivity.

Solvent-Free Approaches for Preparing Dipentaerythritol from Pentaerythritol and 3,3-Bis(hydroxymethyl)oxetane

“…Following these conditions, a 20% DPEO yield, a 31% DPE/PE yield, and a 28% DPE/polyol yield were produced. Separation of the DPE/PE mixture was previously studied in our group …”

“…It can be achieved without a solvent from melted PE or solid PE and with a solvent (sulfolane, tridecane, tetralin, and water) at high temperatures (from 175 to 260 °C). Several catalysts were reported to perform this transformation, such as phosphoric acid, sulfuric acid, titanium/zirconium/aluminum/nickel and chromium phosphates, and silica-supported (or not) vanadium, titanium, lead, or tin phosphate. − The DPE yields reported are mainly included from 2 to 15%, and the best DPE yields can reach 20–22%.…”

“…The first one regards the physicochemical properties of PE. This polyol melted at 266 °C and is insoluble in most of the usual solvents except in water (46 g/L at 20 °C), dimethyl sulfoxide (44 g/L at 36 °C), and sulfolane (37 g/L at 110 °C). , The second challenge regards the control of DPE selectivity throughout the synthesis. Side reactions occurred from the beginning of the reaction; notably, oligomerization of PE was observed.…”

“…DPE selectivities from 43 to 51% were reported for BHMO conversions from 87 to 100%. Nevertheless, under such conditions, PE can react on itself, producing DPE by dehydration. − Consequently, the yield calculated from the BHMO conversion is probably overestimated; indeed, it would be wise to also regard DPE yields from PE.…”

“…The 3,3-bis-(hydroxymethyl)oxetane (BHMO) oxonium was identified as a reactive intermediate in this reaction (Scheme 1). 27 Thus, the reactivity of such intermediate BHMO appears to be the key to improve DPE production.…”