US PATENT SUBCLASS 549 / 248
.~.~.~.~.~.~.~.~ Preparing by oxidation

Current as of: June, 1999
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549 /   HD   ORGANIC COMPOUNDS -- PART OF THE CLASS 532-570 SERIES

*  DD  ORGANIC COMPOUNDS (Class 532, Subclass 1) {1}
*  DD  .~ HETEROCYCLIC CARBON COMPOUNDS CONTAINING A HETERO RING HAVING CHALCOGEN (I.E., OXYGEN, SULFUR, SELENIUM, OR TELLURIUM) OR NITROGEN AS THE ONLY RING HETERO ATOMS (Class 540, subclass 1) {2}
200  DF  .~.~ Oxygen containing hetero ring (e.g., dioxirane, etc.) {16}
231  DF  .~.~.~ Cyclic anhydrides (i.e., -C(=X)OC(=X)-, wherein the X's are the same or diverse chalcogens, is part of the hetero ring) {2}
233  DF  .~.~.~.~ The cyclic anhydride is five-membered (e.g., succinic anhydride, etc.) {7}
234  DF  .~.~.~.~.~ Polycyclo ring system having the cyclic anhydride as one of the cyclos {3}
240  DF  .~.~.~.~.~.~ Bicyclo ring system having the cyclic anhydride as one of the cyclos {5}
247  DF  .~.~.~.~.~.~.~ Phthalic anhydride per se {2}
248.~.~.~.~.~.~.~.~ Preparing by oxidation {1}
249  DF  .~.~.~.~.~.~.~>.~.~ Fluidized catalyst

DEFINITION

Classification: 549/248

(under subclass 247) Processes for the preparation of phthalic anhydride, per se, by an oxidation reaction.

(1) Note. Examples of processes provided for herein are the oxidation of naphthalene or of orthoxylene to phthalic anhydride.