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US 6,476,238 B1Granted
Purification method for obtaining high-purity PMDA
AssigneeChinese Petroleum Corporation
InventorsShiao-Jung Chu, Chien-Liang Hwang
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Abstract
A purification method for obtaining high-purity PMDA. The method controls temperatures of cyclone separators in a series to separate PMDA and other by-products of different sublimation temperatures. High-purity PMDA is collected in the first cyclone separator, and no other purification steps are needed.
Claims15
A purification method for obtaining high-purity PMDA, which comprises:
- connecting a reactor outlet with an inlet of a first cyclone separator in series, wherein the temperature of the reactor outlet is higher than a sublimation temperature of PMDA and the temperature of the first cyclone separator is lower than the sublimation temperature of PMDA and higher than that of by-products;
- and
- directing vapors of the PMDA and the by-products to flow from the reactor outlet to the inlet of the first cyclone separator at a flow rate to obtain high-purity PMDA in the first cyclone separator.
A purification method for obtaining high-purity PMDA, which is applicable to the oxidation of durene to gain PMDA and comprises:
- connecting a reactor with a first cyclone separator in series, wherein the temperature of the reactor is about 245 to about 255° C. and the temperature of the first cyclone separator is about 165 to about 210° C.;
- and
- directing vapors of the PMDA and the by-products to flow from the reactor to the first cyclone separator at a flow rate to obtain PMDA with purity larger than 99.0% in the first cyclone separator.
Dependencies are inferred from the claim text.