US PATENT SUBCLASS 548 / 555
.~.~.~.~.~ Purification or recovery of 2-pyrrolidone which is unsubstituted or alkyl substituted only


Current as of: June, 1999
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548 /   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) {4}
400  DF  .~.~ Hetero ring is five-membered consisting of one nitrogen and four carbons (e.g., halopyrrolidines, etc.) {20}
541  DF  .~.~.~ Chalcogen attached directly to the five-membered hetero ring by nonionic bonding (e.g., 3-pyrrolidinols, etc.) {3}
543  DF  .~.~.~.~ Chalcogen bonded directly to a ring carbon of the five-membered hetero ring which is adjacent to the ring nitrogen (e.g., 2-pyrrolidones, etc.) {6}
555.~.~.~.~.~ Purification or recovery of 2-pyrrolidone which is unsubstituted or alkyl substituted only


DEFINITION

Classification: 548/555

(under subclass 543) Processes wherein 2-pyrrolidone, which is unsubstituted or alkyl substituted only, is separated from impurities, or from the reaction medium.