Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB31585/56A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Wyeth Holdings LLC
Original Assignee
American Cyanamid Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by American Cyanamid CofiledCriticalAmerican Cyanamid Co
Publication of GB806674ApublicationCriticalpatent/GB806674A/en
Organic Low-Molecular-Weight Compounds And Preparation Thereof
(AREA)
Abstract
Cyanuric acid is prepared by heating urea and/or biuret in an inert phenolic solvent therefor to at least 175 DEG C., until ammonia ceases to evolve, and recovering cyanuric acid as a crystalline precipitate. Solvents may be phenol, cresol, xylenol, a 50/50 mixture of o- and p-cresol, or cresylic acid. Weight ratio of urea or biuret to solvent may be 0.5 : 1 to 5 : 1, preferably 1 : 1. Temperatures up to the boiling point of the phenol may be used, or above under superatmospheric pressure. The separated crystals may be washed with an aromatic hydrocarbon solvent, e.g. benzene, or toluene, to remove residual phenol, or the crystals may be steam distilled and dried. The solvent may be re-used.
GB31585/56A1955-10-311956-10-17Improvements in the preparation of cyanuric acid from urea and/or biuret
ExpiredGB806674A
(en)
An improved process for working up spent gas-purification material to pure tar-free sulphur and tar-free purification material capable of being used again