Sulfuric Acid → Cyanuric acid
Reaction equation
S(=O)(=O)(O)O.N1C(N)=NC(N)=NC=1N.C1(N)NC(N)=NC(=[O:18])N=1.[C:24]1([NH2:32])[NH:31][C:29](=[O:30])[NH:28][C:26](=[O:27])[N:25]=1>>[NH:31]1[C:24](=[O:18])[NH:25][C:26](=[O:27])[NH:28][C:29]1=[O:30].[C:24]1([NH2:32])[NH:31][C:29](=[O:30])[NH:28][C:26](=[O:27])[N:25]=1Participants
Conditions
- Temperature
- 160 °C
Procedure
333 kg Of 70% strength sulfuric acid is initially introduced into an enamel kettle and 100 kg of a waste melamine which contains ammeline and ammelide and has a melamine content of about 95% is added, with stirring, the temperature rising to about 90° C. This suspension is heated to the boiling point of 132° C. and is then heated up to 160° C. in the course of one hour, whilst distilling off water. The suspension is kept at the boil under reflux, at 160° C. for 4 hours and 310 l. of water is then added, the temperature falling to 120° C. After cooling to room temperature, the cyanuric acid is centrifuged off, washed and suspended in water, using a weight ratio of 1 part of cyanuric acid to 2 parts of water, the suspension is stirred for one hour at room temperature and the cyanuric acid is centrifuged off and washed. About 96 kg. (93.9%) of a cyanuric acid with an ammelide content of less than 0.3% is obtained. The ammonium bisulfate impurity amounts to about 0.03%. Melamine and ammeline are not detectable.
Workup
- additionis added
- customrising to about 90° C
- temperatureThis suspension is heated to the boiling point of 132° C.
- distillationwhilst distilling off water
- temperatureunder reflux, at 160° C. for 4 hours
- additionof water is then added
- customfalling to 120° C
- temperatureAfter cooling to room temperature
- washwashed
- stirringthe suspension is stirred for one hour at room temperature
- washwashed
Sources & evidence
- ORD record
- ord-a913c5b685174e1d92b1efb4f0293bc7
- Source dataset
- uspto-grants-1981_07
- Patent number
- US04278794
Reaction notes
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