Continuous process for crystallizing nitroguanidine (USH0001510)
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Del.icio.us| IP.com Number | IPCOM000001491D |
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| Dated | Dec 5, 1995 UTC | ||
| Size | 5 page(s) (0.75 MB) | ||
| Disclosed by |
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Publication Summary
A continuous process for forming spheroidal high bulk density nitroguanid crystals from an aqueous solution of nitroguanidine which contains methylcellulose and partially hydrolyzed poly(vinyl alcohol) as crystal habit modifiers. A saturated aqueous solution of nitroguanidine is formed at a temperature T.sub.1 where 70.degree. C..ltoreq.T.sub.1 .ltoreq.100.degree. C. and crystallization occurs at a lower temperature T.sub.2 where 20.degree. C..ltoreq.T.sub.1 -T.sub.2 .ltoreq.50.degree. C.| Country | United States |
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| Language | English (United States) |
| Related Person(s) |
(ATTORNEY) Walden, Kenneth E. (INVENTOR) Collignon, Steven L. (INVENTOR) Wagaman, Kerry L. (OWNER) The United States of America as represented by the Secretary of the Navy |
| Related Document(s) |
(PATENT) USH001510
(PATAPP) US210881 |
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United States Patent |
USH0001510 |
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Collignon , et al. |
December 5, 1995 |
Continuous process for crystallizing nitroguanidine
Abstract
A continuous process for forming spheroidal high bulk density nitroguanid crystals from an aqueous solution of nitroguanidine which contains methylcellulose and partially hydrolyzed poly(vinyl alcohol) as crystal habit modifiers. A saturated aqueous solution of nitroguanidine is formed at a temperature T.sub.1 where 70.degree. C..ltoreq.T.sub.1 .ltoreq.100.degree. C. and crystallization occurs at a lower temperature T.sub.2 where 20.degree. C..ltoreq.T.sub.1 -T.sub.2 .ltoreq.50.degree. C.
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Inventors: |
Collignon; Steven L. (Waldorf, MD); Wagaman; Kerry L. (Waldorf, MD) |
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Assignee: |
The United States of America as represented by the Secretary of the Navy (Washington, DC) |
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Appl. No.: |
210881 |
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Filed: |
June 23, 1988 |
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Current U.S. Class: |
564/242 |
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Intern'l Class: |
C07C 277/08 |
References Cited [Referenced By]
Primary Examiner: Stoll; Robert L.
Assistant Examiner: Covert; John M.
Attorney, Agent or Firm: Walden; Kenneth E.
Claims
What is claimed is:
1. A continuous process for recrystallizing nitroguanidine comprising the
following steps in order:
(1) forming a saturated aqueous nitroguanidine solution at a constant
temperature T.sub.1 which is in the range of from about 70.degree. C. to about
100.degree. C. wherein the solution also contains from 0.5 to 2.0 weight
percent of methylcellulose and from 0.5 to 2.0 weight percent of a partially
hydrolyzed poly(vinyl alcohol);
(2) feeding the solution formed in step (1) into a crystallizer containing a saturated
aqueous solution of nitroguanidine which is maintained at a constant
temperature of T.sub.2 wherein 20.degree. C..ltoreq.T.sub.1 -T.sub.2
.ltoreq.50.degree. C. and wherein the methylcellulose and partially hydrolyzed
poly(vinyl alcohol) concentrations are the same as in the feed solution;
(3) separating the product spheroidal or ovate nitroguanidine crystals from the
supernatant aqueous nitroguanidine solution; and
(4) recycling the separated supernatant aqueous nitroguanidine solution to be used
again in step (1).
2. The process of claim wherein the solution in the crystalizer in step (2) is
continuously agitated.
3. The process of claim 1 wherein 80.degree. C..ltoreq.T.sub.1
.ltoreq.100.degree. C.
4. The process of claim 3 wherein 30.degree. C..ltoreq.T.sub.1 -T.sub.2
.ltoreq.40.degree. C.
5. The process of claim 1 wherein 30.degree. C..ltoreq.T.sub.1 -T.sub.2
.ltoreq.40.degree. C.
6. The process of claim 1 wherein the concentration of methylcellulose in the
aqueous nitroguanidine solutions is from 0.5 to 1.0 percent by weight.
7. The process of claim 6 wherein the concentration of partially hydrolyzed
poly(vinyl alcohol) in the aqueous nitroguanidine solutions is from 0.5 to 1.0
percent by weight.
8. The process of claim 1 wherein the concentration of partially hydrolyzed
poly(vinyl alcohol) in the aqueous nitroguanidine solutions i...