| 摘要 |
1305041 Hexamethylene tetramine TENNECO CHEMICALS Inc 31 Dec 1969 [31 Dec 1968] 63549/69 Heading C2C Uniform free-flowing spheres of hexamethylenetetramine are prepared by: (a) continuously introducing into a reaction zone gaseous ammonia and an aqueous solution containing 30- 5% (by weight) of formaldehyde and having a low cation content in a molar ratio of approximately 0À67 to 1; (b) heating the mixture to a temperature in the range 50-90‹ C. at a pH of 7À0 to 8À0 for 1-10 minutes; (c) continuously withdrawing the aqueous solution of hexamethylene tetramine from the reaction zone; (d) passing air heated to a temperature below the decomposition temperature of hexamethylenetetramine up through a confined zone containing finely-divided particles of hexamethylenetetramine at a flow rate sufficient to form a fluidized bed; (e) spraying into the fluidized bed the aqueous solution of hexamethylenetetramine obtained in step (c) in an amount such that the water in the solution is vaporized and the solid particles are coated with the solution; (f) injecting into the fluidized bed by means of air, particles of hexamethylenetetramine of a size smaller than the average size of the particles present in the bed, the particles being injected downwardly and transversely to the heated air flow in the bed; (g) continuously discharging a portion of the hexamethylenetetramine pellets from the bed; and (h) screening the discharged pellets to obtain a uniform free-flowing product. |
