The invention relates to a preparation method of di-tert-butyl
dicarbonate and belongs to the technical field of synthesis of pharmaceutical intermediates. The preparation method comprises the following steps: adding
metal sodium into xylol; heating to obtain
sodium sand; then dropwise adding tert-butyl
alcohol and carrying out pumping
filtration to obtain
sodium tert-butoxide; dissolving the sodium tert-butoxide into
petroleum ether; introducing
carbon dioxide and reacting to obtain a monoester
sodium salt solution; adding a catalyst and slowly dropwise adding
diphosgene to react; after reacting, standing and carrying out the pumping
filtration; and washing with water,
drying, distilling, cooling and crystallizing to obtain the di-tert-butyl
dicarbonate. According to the preparation method, the sodium tert-butoxide is prepared from the
metal sodium and the di-tert-butyl
dicarbonate is prepared from the sodium tert-butoxide; a pumping
filtration method is used for replacing a previous
distillation method, so that the process is simpler and more energy is saved; the
petroleum ether is used for replacing n-
hexane and
toluene, so that the production cost is reduced and a product is easier to purify; and finally, after the reaction, the pumping filtration is carried out and then
water washing is carried out, so that the amount of
wastewater is reduced and the environment-friendly treatment cost is reduced.