Method of purifying propylene oxide
A technology of propylene oxide and epoxidation, applied in directions such as organic chemistry, can solve problems such as removal and reduction of undisclosed impurity methyl formate
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Embodiment 1
[0050] Propylene oxide obtained by reacting cumene hydroperoxide and propylene in the presence of a titanium-containing silica catalyst was used. Propylene oxide contained 50 wt. ppm of methyl formate as an impurity.
[0051] Propylene oxide is subjected to extractive distillation with n-heptane as extractant. 3.4 parts by weight of n-heptane were used with respect to 1 part by weight of propylene oxide. A tray-type extractive distillation column was used, and the operating conditions were 103° C. at the bottom of the column, 85° C. at the top of the column, and 220 kPa at the top of the column.
[0052] Water is added to the distillate obtained from the top of the extractive distillation tower to perform an oil-water separation operation, and the separated oil layer is reused in the extractive distillation tower, while the separated water layer is removed outside the system. The amount of water added was 0.06 parts by weight. The concentration of methyl formate in the sepa...
Embodiment 2
[0055] Utilize Na 2 CO 3 The pH value of 20 g of the aqueous solution containing 5.3% by weight propylene glycol (PG), 420 wt. ppm methyl formate and a small amount of organic acid was adjusted to 8.2. , 4.6% by weight propylene oxide (PO) n-heptane solution was stirred and mixed at 27°C for 3 minutes, left to stand, and oil-water separation was carried out.
[0056] The amounts of propylene glycol and methyl formate in the oil layer and the water layer after standing separation are shown in Table 1. In addition, the propylene glycol increased by the hydration reaction of propylene oxide was calculated as the loss of propylene oxide.
[0057] Table 1
[0058] Example 2 Example 3 pH value of water layer 8.2 8.8 raw material
Embodiment 3
[0060] Except that the pH value of water was adjusted to 8.8, it carried out by the same method as Example 2. The results are shown in Table 1.
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