Organic compounds -- part of the class 532-570 series – Organic compounds – Four or more ring nitrogens in the bicyclo ring system
Patent
1998-06-10
1999-12-28
Ford, John M.
Organic compounds -- part of the class 532-570 series
Organic compounds
Four or more ring nitrogens in the bicyclo ring system
C07D25170, C07F 922
Patent
active
060083492
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a melamine polymetaphosphate and a process for its production.
BACKGROUND ART
With respect to melamine polyphosphate, various types of melamine polyphosphate compounds are disclosed in literatures. For example, JP-B-40-28594 discloses a process which comprises calcining melamine orthophosphate at a temperature of from 180 to 250.degree. C. to obtain a calcined melamine phosphate wherein a part of melamine orthophosphate remains. However, it has been pointed out that this melamine phosphate is a composite of melamine orthophosphate and melamine pyrophosphate and does not have adequate water resistance.
U.S. Pat. No. 3,920,796 discloses that melamine pyrophosphate is formed by calcining melamine orthophosphate at a temperature of from 170 to 325.degree. C.
Further, U.S. Pat. No. 4,950,757 discloses a process for producing melamine pyrophosphate, which comprises reacting pyrophosphoric acid and melamine in an aqueous medium at a temperature of from 0 to 60.degree. C.
JP-A-61-126091 discloses a process for producing melamine condensed phosphate, which comprises subjecting condensed phosphoric acid and melamine to a solid phase reaction substantially in the absence of an aqueous medium at a temperature of from naturally generated temperature to 170.degree. C.
It is known to employ urea as a condensing agent for the production of a polyphosphate. For example, JP-B-53-2170 discloses a process for producing an amide polyphosphate containing amide-type nitrogen, wherein a phosphoric acid source, such as ammonium orthophosphate, orthophosphoric acid, condensed phosphoric acid, phosphoric anhydride, urea phosphate or a mixture thereof, and a nitrogen source, such as melamine, a cyanamide derivative such as dicyan cyanamide, guanidine or guanyl urea, or a mixture thereof, are subjected to a heat condensation reaction in the presence of a condensing agent, such as urea, urea phosphate or a mixture thereof. With respect to the production conditions, it is disclosed that heat condensation is carried out at a molar ratio of urea/phosphoric acid (as H.sub.3 PO.sub.4)/cyanamide derivative=0.8 to 1.5/1/0.05 to 1 in an atmosphere of ammonia gas at a temperature of from 150 to 350.degree. C. for from 10 minutes to 5 hours, preferably from 1 to 4 hours. Example 1 of the same publication discloses that ammonium phosphate, industrial urea and melamine were mixed at a molar ratio of urea/phosphoric acid (as H.sub.3 PO.sub.4)/melamine=1/1/0.5 to obtain a material for calcination, which was subjected to heat condensation at a temperature of from 240 to 260.degree. C. for 2.5 hours to obtain a substantially water-insoluble amide polyphosphate (nitrogen: 33.48 wt %, diphosphorus pentoxide: 44.73 wt %, elution ratio (10 g of a sample was put into 100 ml of water and stirred for 1 hour at a predetermined temperature, whereupon the elution ratio (%) was determined): 1.36%, pH of the 1% solution: 8.26).
JP-B-53-15478 discloses a process for producing an ammonium polyphosphate hardly soluble in water, which comprises calcining crystalline urea phosphate, or ammonium phosphate and urea, as starting material, wherein the starting material is heat-condensed in the presence of melamine or melamine phosphate in an amount of from 5 to 50 wt % as melamine (based on the total amount of the starting material and melamine or melamine phosphate) to obtain a modified ammonium polyphosphate. Example 1 of the same publication discloses that a starting material prepared by mixing ammonium phosphate, industrial urea and melamine at a molar ratio of urea/phosphoric acid (as H.sub.3 PO.sub.4)/melamine=1/1/0.5, was subjected to heat condensation by a rotary indirect heating furnace at a temperature of from 260 to 270.degree. C. for 1.5 hours to obtain a product, then the product was pulverized to a particle size whereby all particles pass through 32 mesh (standard sieve) and then subjected to heat condensation by a rotary indirect heating furnace in an ammonia gas atmosphere at 270.degree. C. for 1.5 hours
REFERENCES:
patent: 3920796 (1975-11-01), Sheridan et al.
patent: 4043987 (1977-08-01), Jolicoeur et al.
patent: 4950757 (1990-08-01), Tomko et al.
Shindo Masuo
Shishido Kouji
Suzuki Keitaro
Ford John M.
Nissan Chemical Industries Ltd.
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