Sulfuric Acid → Isosorbide

Beteiligte Stoffe

Reaktionsschritte

1.548 g (8.5 mol) of sorbitol, 3,000 ml of xylene and 20 ml of concentrated sulfuric acid were heated to reflux with stirring and about 306 ml of water were removed. The xylene was then removed by distillation (the last amount under vacuum) and the residue was taken up in 3,000 ml of tert.-butanol, heated to 55° to 65° C., 2,432 ml (30.4 mol) of an aqueous solution of sodium hydroxide and 2,682 g (21.25 mol) of dimethyl sulfate were added dropwise simultaneously at this temperature while keeping the mixture always alkaline. When the addition is completed, the mixture was stirred for three hours at 60° C. and the alcohol was then removed up to a distillation temperature of 97° to 98° C. The residue was taken up in 8,500 ml of water and the aqueous solution was extracted three times with 1,000 ml portions of ethylene chloride. The solvent was evaporated from the combined organic phases and was fractioned in a column to recover the fraction in the boiling range of 118° to 120° C. mbar which was 1,037 g (70% yield) of dimthyl isosorbide.

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