US3903158A
Expired / Lapsed
US
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Process for reducing the biuret content in urea
Assignee: GUANOS Y FERTILIZANTES DE MEXICO SA
•
Filing: 1973-05-16
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Granted: 1975-09-02
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Expires: 1993-05-16
Abstract
Abstract The present invention refers to a process for reducing the biuret content of melted urea or urea in solution by placing said urea in contact with ion exchanging resins.
Inventors
- 👤 Jose Cabello Fuentes
- 👤 Ramon Xutgla Marin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 13:09
CPC Classifications
C; C07; C07C; C07C273/00; C07C273/02; C07C273/14; C07C273/16
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
77 words
A PROCESS FOR PREFERENTIALLY REDUCING ANY UNDESIRABLE BIURET CONTENT IN UREA HAVING A LOW AMOUNT OF BIURET IN THE RANGE OF 2.92 PER CENT OR LESS ON A DRY WEIGHT BASIS AS AN IMPURITY RELATIVE TO SAID UREA, SAID UREA, COMPRISING EITHER MOLTEN UREA OR UREA IN AQUEOUS SOLUTION HAVING CONCENTRATIONS OF 1.0 TO 99.9% OF UREA, IN WHICH SAID MOLTEN UREA OR SAID UREA IN SOLUTION IS PLACED IN CONTACT WITH ACIDIC OR BASIC ION EXCHANGERS.
Claim 2
Dependent Claim
77 words
A PROCESS FOR PREFERENTIALLY REDUCING ANY UNDESIRABLE BIURET CONTENT IN UREA HAVING A LOW AMOUNT OF BIURET IN THE RANGE OF 2.92 PER CENT OR LESS ON A DRY WEIGHT BASIS AS AN IMPURITY RELATIVE TO SAID UREA, SAID UREA, COMPRISING EITHER MOLTEN UREA OR UREA IN AQUEOUS SOLUTION HAVING CONCENTRATIONS OF 1.0 TO 99.9% OF UREA, IN WHICH SAID MOLTEN UREA OR SAID UREA IN SOLUTION IS PLACED IN CONTACT WITH ACIDIC OR BASIC ION EXCHANGERS.
Claim 3
Dependent Claim
18 words
The process as claimed in claim 1, wherein the ion exchanging resin is a strong base anionic resin.
Claim 4
Dependent Claim
23 words
The process as claimed in claim 2, wherein the operating temperature for said biuret reduction is within the range of 0* to 200*C.
Claim 5
Dependent Claim
14 words
The process as claimed in claim 3, which is carried by batch ion exchange.
Claim 6
Dependent Claim
15 words
The process as claimed in claim 3, which is carried out by continuous ion exchange.
Claim 7
Dependent Claim
19 words
The process according to claim 1 wherein said urea is in a substantially saturated solution of urea in water.
References Cited (Backward Citations)
US3151156A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |