Process for the Production of 3-Alkyl-3-Hydroxymethyloxetanes

Gaudi etal, US Patent 6,166,228 (December 26, 2000) Assignee Dainippon Ink and Chemicals, Inc. 

A 20L steel reactor was charged with trimethylolpropane (55 mol), diethyl carbonate (55 mol) and K2CO3 (76 g) and stirred 6 hours at 103-105 °C. Thereafter, the volatile components were distilled from the mixture at the same temperature. Toward the end of the reaction a pressure of 150-200 hPa was established at a temperature of 135-140 °C. After an additional 4 hours, the pressure was further lowered to 33 hPa and product began to distill until a 87% yield was collected. 

This is a 3 stage reaction. In the first stage, the reaction mixture is heated to reflux for 6 hours at a temperature range between 90 and 120 °C. In the second stage, ethyl alcohol is distilled off at the same temperature. In the final stage, the mixture is heated to between 125 and 150 °C to decarboxylate and de-oligomerize the intermediate and the product isolation by distillation. 

A conversion of only 42% was observed in the preparation of 3-ethyl-3-hydroxylmethyloxetane using identical reagents and analogous reaction stoichometry when decarboxylation and de-oligomerization was conducted at 220 °C (1). 

l-Di-(3-ethyloxetane)dimethylether was prepared using ditrimethylol-propane (2) as illustrated in Eq. 1  

---