IP Library › Granted Patent US 7,138,528
Granted Patent B2
US 7,138,528 · App. 11/047,843 · Granted Nov 21, 2006

Method for crystallizing N-vinyl-2-pyrrolidone

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Quick Facts
Patent No.
US 7,138,528
App. No.
11/047,843
Granted
Nov 21, 2006
Kind
B2
Abstract

A method for purifying N-vinyl-2-pyrrolidone (NVP) is disclosed. The method comprises crystallizing NVP in the presence of added water to produce purified NVP crystals and a mother liquor, and then isolating the purified crystals. In a preferred method, 0.5 to 4 wt. % of water based on the amount of NVP to be purified is added, and the NVP crystals are washed with additional pure NVP, preferably NVP crystal melt, to give crystals having a purity greater than 99.99%. The method provides a fast, effective way to generate and isolate pure NVP in a single-stage crystallization.

Claims (11)

1. A method which comprises: (a) crystallizing liquid N-vinyl-2-pyrrolidone (NVP) in the presence of added water to produce purified NVP crystals and a mother liquor; and (b) separating the purified NVP crystals from the mother liquor.

2. The method of claim 1 wherein the water is added in an amount within the range of 0.5 to 4 weight percent based on the amount of NVP to be purified.

3. The method of claim 1 wherein the water is added in an amount within the range of 1 to 2 weight percent based on the amount of NVP to be purified.

4. The method of claim 1 wherein the crystallization is performed at a temperature within the range of −5° C. to 15° C.

5. The method of claim 1 wherein the crystallization is performed at a temperature within the range of 4° C. to 10° C.

6. The method of claim 1 wherein the purified NVP crystals are washed with additional pure NVP to a purity greater than 99.99%.

7. The method of claim 6 wherein the washing is repeated to provide NVP having a purity greater than 99.999%.

8. The method of claim 1 wherein separation step (b) is performed by filtration, centrifugation, or both.

9. A method which comprises: (a) crystallizing liquid N-vinyl-2-pyrrolidone (NVP) in the presence of 0.5 to 4 wt. % of added water at a temperature within the range of −5° C. to 15° C. to produce purified NVP crystals and a mother liquor; (b) separating the purified NVP crystals from the mother liquor; and (c) washing the purified NVP crystals with additional pure NVP to a purity greater than 99.99%.

10. The method of claim 9 wherein separation step (b) is performed by filtration, centrifugation, or both.

11. The method of claim 9 wherein step (c) is repeated to provide NVP having a purity greater than 99.999%.

Assignments (12)
RELEASE OF SECURITY INTEREST Recorded May 5, 2010
From: CITIBANK, N.A., AS COLLATERAL AGENT
To: LYONDELL CHEMICAL TECHNOLOGY, LP
Reel/Frame 024337/0020 →
RELEASE OF SECURITY INTEREST Recorded May 5, 2010
From: UBS AG, STAMFORD BRANCH, AS COLLATERAL AGENT
To: LYONDELL CHEMICAL TECHNOLOGY, LP
Reel/Frame 024337/0285 →
RELEASE OF SECURITY INTEREST Recorded May 5, 2010
From: CITIBANK, N.A., AS COLLATERAL AGENT
To: LYONDELL CHEMICAL TECHNOLOGY, L.P.; EQUISTAR CHEMICALS, LP
Reel/Frame 024337/0705 →
RELEASE OF SECURITY INTEREST Recorded May 5, 2010
From: CITIBANK, N.A., AS COLLATERAL AGENT
To: LYONDELL CHEMICAL TECHNOLOGY, L.P.; EQUISTAR CHEMICALS, LP
Reel/Frame 024337/0856 →
SECURITY AGREEMENT Recorded Oct 30, 2009
From: LYONDELL CHEMICAL TECHNOLOGY, L.P.
To: UBS AG, STAMFORD BRANCH, AS COLLATERAL AGENT
Reel/Frame 023449/0138 →
SECURITY AGREEMENT Recorded Apr 9, 2009
From: LYONDELL CHEMICAL TECHNOLOGY, L.P.
To: CITIBANK, N.A., AS ADMINISTRATIVE AGENT AND COLLATERAL AGENT
Reel/Frame 022708/0830 →
SECURITY AGREEMENT Recorded Aug 4, 2008
From: BASELL POLYOLEFINE GMBH; ARCO CHEMICAL TECHNOLOGY L.P.; ARCO CHEMICAL TECHNOLOGY, INC.; ATLANTIC RICHFIELD COMPANY; BASELL NORTH AMERICA, INC.; BASELL POLYOLEFIN GMBH; LYONDELL CHEMICAL COMPANY; EQUISTAR CHEMICALS, L.P.
To: CITIBANK, N.A., AS COLLATERAL AGENT
Reel/Frame 021354/0708 →
GRANT OF SECURITY INTEREST IN UNITED STATES PATENTS AND PATENT APPLICATIONS Recorded Mar 26, 2008
From: BASELL POLYOLEFINE GMBH; ARCO CHEMICAL TECHNOLOGY L.P.; ARCO CHEMICAL TECHNOLOGY, INC.; ATLANTIC RICHFIELD COMPANY; BASELL NORTH AMERICA, INC.; EQUISTAR CHEMICALS. LP.; LYONDELL CHEMICAL COMPANY; LYONDELL CHEMICAL TECHNOLOGY, L.P.; LYONDELL PETROCHEMICAL COMPANY; NATIONAL DISTILLERS AND CHEMICAL CORPORATION; OCCIDENTAL CHEMICAL CORPORATION; OLIN CORPORATION; QUANTUM CHEMICAL CORPORATION; BASELL POLYOLEFIN GMBH
To: CITIBANK, N.A., AS COLLATERAL AGENT
Reel/Frame 020704/0562 →
RELEASE OF LYONDELL CHEMICAL TECHNOLOGY, L.P. PATENT SECURITY AGREEMENT Recorded Mar 20, 2008
From: JPMORGAN CHASE BANK, N.A.
To: LYONDELL CHEMICAL TECHNOLOGY, L.P.
Reel/Frame 020679/0063 →
SECURITY AGREEMENT Recorded Sep 15, 2006
From: LYONDELL CHEMICAL TECHNOLOGY, L.P.
To: JPMORGAN CHASE BANK N.A., AS ADMINISTRATIVE AGENT
Reel/Frame 018260/0306 →
CHANGE OF NAME Recorded Jun 27, 2005
From: ARCO CHEMICAL TECHNOLOGY, L.P.
To: LYONDELL CHEMICAL TECHNOLOGY, L.P.
Reel/Frame 016206/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Mar 21, 2005
From: GUPTA, VIJAI P.; CAREY, EDWARD P.
To: ARCO CHEMICAL TECHNOLOGY, L.P.
Reel/Frame 016413/0471 →