carbamoylurea

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: As set forth above the process of the invention is directed to heating urea and/or biuret dissolved in the reaction medium containing a dissolved acid or a corresponding anhydride or ammonium salt to produce cyanuric acid, vapor being discharged during the reaction. dissolved in the reaction medium containing a dissolved acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: As set forth above the process of the invention is directed to heating urea and/or biuret dissolved in the reaction medium containing a dissolved acid or a corresponding anhydride or ammonium salt to produce cyanuric acid, vapor being discharged during the reaction. dissolved in the reaction medium containing a dissolved acid

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Two-three heated moles of ammonia to one mol of heated carbon dioxide, heated at 160 to 210 degree C. is forced through a reactor which has an aqueous solution or oil-water slurry of ammonia and carbon dioxide which is being circulated at 160° to 210° C. and under 2-6000 psi to form ammonium carbamate which when heated lose 1 mol of water thereby producing an aqueous urea. The aqueous urea contains small amounts of ammonia, ammonium carbonate and biuret. The aqueous urea is concentrated and the urea crystalizes out. The urea may be heated to above the boiling point of urea to produce biuret or cyanuric acid and cyamelide. When urea is heated with a small amount of water it condensates to for a partially hydrolyzed urea condensate. The aqueous urea is concentrated the urea crystalizes out The urea may be heated to above the boiling point of urea

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Two-three heated moles of ammonia to one mol of heated carbon dioxide, heated at 160 to 210 degree C. is forced through a reactor which has an aqueous solution or oil-water slurry of ammonia and carbon dioxide which is being circulated at 160° to 210° C. and under 2-6000 psi to form ammonium carbamate which when heated lose 1 mol of water thereby producing an aqueous urea. The aqueous urea contains small amounts of ammonia, ammonium carbonate and biuret. The aqueous urea is concentrated and the urea crystalizes out. The urea may be heated to above the boiling point of urea to produce biuret or cyanuric acid and cyamelide. When urea is heated with a small amount of water it condensates to for a partially hydrolyzed urea condensate. The aqueous urea is concentrated the urea crystalizes out The urea may be heated to above the boiling point of urea

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Two-three heated moles of ammonia to one mol of heated carbon dioxide, heated at 160 to 210 degree C. is forced through a reactor which has an aqueous solution or oil-water slurry of ammonia and carbon dioxide which is being circulated at 160° to 210° C. and under 2-6000 psi to form ammonium carbamate which when heated lose 1 mol of water thereby producing an aqueous urea. The aqueous urea contains small amounts of ammonia, ammonium carbonate and biuret. The aqueous urea is concentrated and the urea crystalizes out. The urea may be heated to above the boiling point of urea to produce biuret or cyanuric acid and cyamelide. When urea is heated with a small amount of water it condensates to for a partially hydrolyzed urea condensate. The aqueous urea is concentrated the urea crystalizes out The urea may be heated to above the boiling point of urea

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The selective control over pH may be accomplished using any of a variety of well-known buffering systems known in the art. One such buffering system utilizes urea thermal decomposition (i.e., pyrolysis) to increase pH to the desired value. The pyrolysis of urea is well known, and has been described in, for instance, Study of the Urea Decomposition (Pyrolysis) Reaction and Importance to Cyanuric Acid Production, Peter M. Shaber, et al., American Laboratory (August 1999), which is incorporated herein in its entirety by reference thereto for all purposes. For instance, to initiate the pyrolysis reaction, urea is first heated to its melting point of approximately 135° C. With continued heating to approximately 150° C., the urea is vaporized (Eq. 1) and is then decomposed into ammonia and isocyanic acid (Eq. 2). The urea also reacts with the isocyanic acid byproduct to form biuret (Eq. 3). H2N—CO—NH2(m)+heat=H2N—CO—NH2(g)  (1) H2N—CO—NH2(g)+heat NH3(g)+HNCO(g)  (2) H2N—CO—NH2(m)+HNCO(g)H2N—CO—NH—CO—NH2(s)  (3) Upon further heating, e.g., to about 175° C., the biuret referenced above reacts with isocyanic acid to form cyanuric acid and ammonia (Eq. 4), as well as ammelide and water (Eq. 5). H2N—CO—NH—CO—NH2(m)+HNCO(g)CYA(s)+NH3(g)  (4) H2N—CO—NH—CO—NH2(m)+HNCO(g)ammelide(s)+H2O(g)  (5) As the temperature is further increased, other reactions begin to occur. For instance, biuret may decompose back into urea and isocyanic acid. The urea produced is unstable at higher temperatures, and thus, will further decompose into ammonia and isocyanic acid. Urea and the byproducts of the pyrolysis reaction will continue to react and further decompose as the reaction mixture is heated. to about 175° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The selective control over pH may be accomplished using any of a variety of well-known buffering systems known in the art. One such buffering system utilizes urea thermal decomposition (i.e., pyrolysis) to increase pH to the desired value. The pyrolysis of urea is well known, and has been described in, for instance, Study of the Urea Decomposition (Pyrolysis) Reaction and Importance to Cyanuric Acid Production, Peter M. Shaber, et al., American Laboratory (August 1999), which is incorporated herein in its entirety by reference thereto for all purposes. For instance, to initiate the pyrolysis reaction, urea is first heated to its melting point of approximately 135° C. With continued heating to approximately 150° C., the urea is vaporized (Eq. 1) and is then decomposed into ammonia and isocyanic acid (Eq. 2). The urea also reacts with the isocyanic acid byproduct to form biuret (Eq. 3). H2N—CO—NH2(m)+heatH2N—CO—NH2(g)  (1) H2N—CO—NH2(g)+heatNH3(g)+HNCO(g)  (2) H2N—CO—NH2(m)+HNCO(g)H2N—CO—NH—CO—NH2(s)  (3) Upon further heating, e.g., to about 175° C., the biuret referenced above reacts with isocyanic acid to form cyanuric acid and ammonia (Eq. 4), as well as ammelide and water (Eq. 5). H2N—CO—NH—CO—NH2(m)+HNCO(g)CYA(s)+NH3(g)  (4) H2N—CO—NH—CO—NH2(m)+HNCO(g)ammelide(s)+H2O(g)  (5) As the temperature is further increased, other reactions begin to occur. For instance, biuret may decompose back into urea and isocyanic acid. The urea produced is unstable at higher temperatures, and thus, will further decompose into ammonia and isocyanic acid. Urea and the byproducts of the pyrolysis reaction will continue to react and further decompose as the reaction mixture is heated. to about 175° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: When molten urea is heated first at atmospheric pressure and thereafter under vacuum, there is a rapid evolution of ammonia upon the application of the vacuum. This indicates the presence of a substantial quantity of biuret precursor moieties generated during the pyrolysis at atmospheric pressure. These active bodies then react under the influence of reduced pressure to give enhanced yields of biuret without excessive production of cyanuric acid. These active bodies then react under the influence of reduced pressure to give enhanced

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Cyanuric acid can be produced by heating urea or biuret in a solvent medium. During the process, particles of cyanuric acid are formed as a slurry in the hot solvent. Previous processes have employed operations to cool the reaction slurry and to separate the cyanuric acid from the slurry in which cyanuric acid was deposited on the cooling surfaces and the resulting product was discolored.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: The solution of urea and/or biuret in the inert organic solvent is circulated at high velocity through the recycle loop and is maintained at a temperature of not less than 180° C. or higher thereby forming a solution or slurry of cyanuric acid in the inert organic solvent. The crystallizer heretofore mentioned is maintained at subatmospheric pressure and the solution or slurry is introduced therein in a manner as to maximize agitation of the solution or slurry of cyanuric acid. is maintained at a temperature of not less than 180° C.

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: As set forth above the process of the invention is directed to heating urea and/or biuret dissolved in the reaction medium containing a dissolved acid or a corresponding anhydride or ammonium salt to produce cyanuric acid, vapor being discharged during the reaction. dissolved in the reaction medium containing a dissolved acid