A Publication
of Reliable Methods
for the Preparation
of Organic Compounds
Annual Volume
Org. Synth. 1953, 33, 13
DOI: 10.15227/orgsyn.033.0013
[s-Triazine, 2,4-diamino-6-phenyl-]
Submitted by J. K. Simons and M. R. Saxton1.
Checked by T. L. Cairns and A. K. Schneider.
1. Procedure
Five grams of potassium hydroxide (85% KOH) is dissolved in 100 ml. of methyl Cellosolve (Note 1) in a 500-ml. flask (Note 2) fitted with a mechanical stirrer, reflux condenser, and a heating mantle. Dicyandiamide (50.4 g.; 0.6 mole) (Note 3) and benzonitrile (50 g.; 0.48 mole) are added, and the mixture is stirred and heated. A solution is formed, and, when the temperature reaches 90–110°, an exothermic reaction begins and the product separates as a finely divided white solid. The vigor of the reaction is kept under control by the refluxing of the solvent (Note 4).
When the exothermic reaction is ended, the slurry of product is stirred and refluxed for 5 hours to ensure complete reaction (Note 5). The mixture is then cooled and filtered. The product is washed by suspension in hot water (Note 6), filtered, and dried. The yield is 68–79 g. (75–87%). The product melts at 227–228° (Note 7).
2. Notes
1. The commercial solvent is used without purification. Other primary alcohols of similar or higher boiling point are suitable solvents.
2. The large flask is chosen to allow for better stirring and heat transfer.
3. The reaction may be carried out with exactly molar equivalents of reactants. Slightly better yields are obtained by using the 0.2 to 0.25 molar excess of dicyandiamide.
4. Boiling of the methyl Cellosolve dissipates the heat of reaction, which begins at about 90°. The submitters state that, in one preparation using 100 times the indicated quantities (21-l. flask), two condensers were used and intermittent cooling of the flask with a small stream of water kept the boiling from becoming too violent.
5. Yields reported were obtained after 5 hours under reflux. Preparation of other guanamines indicates an optimum yield after 2.5 hours under reflux.
6. Thorough washing with hot water serves to remove any dicyandiamide or melamine which may be present in the crude product. Benzoguanamine is slightly soluble in hot water.
7. The Cellosolve filtrate may be evaporated to obtain further quantities of product, m.p. 227–228°, raising the total yield to 90–95%.
3. Discussion
Benzoguanamine has been prepared by the reaction of dicyandiamide with benzonitrile in a sealed tube at 220–230°,2 with an excess of benzonitrile in the presence of piperidine and potassium carbonate,3 with benzonitrile in a solvent in the presence of a basic catalyst,4 with benzonitrile in liquid ammonia,5 and with benzamidine hydrochloride at elevated temperatures.6 7 It also has been prepared from the reaction of biguanide acetate with benzamidine hydrochloride,8 or of biguanide sulfate with benzoyl chloride in an alkaline medium,9 by the distillation of guanidine benzoate,6 and from benzonitrile, urea, and ammonia.10

References and Notes
  1. Plaskon Division, Libby-Owens-Ford Glass Company, Toledo 6, Ohio.
  2. Ostrogovich, Atti accad. Lincei, [5] 20, I, 251 [C.A., 5, 2099 (1911)].
  3. DeBell, Goggin, and Gloor, German Plastics Practice, p. 267, DeBell and Richardson, Springfield, Massachusetts, 1946.
  4. Zerweck and Brunner (vested in the Alien Property Custodian) U. S. pat. 2,302,162 [C.A., 37, 2016 (1943)]; Thrower and Pinchin (to British Oxygen Co.) Brit. pat. 758,601 [C. A., 51, 10593 (1957)]; Jones (to British Oxygen Co.) U. S. pat. 2,735,850 [C. A., 50, 15598 (1956)].
  5. Bann, Grimshaw, Jones, and Pinchin, Compt. rend. 27° congr. intern. ind. Brussels, 1954, 3; Industrie chim. belge, 20, Spec. No. 342 (1955) [C. A., 50, 11053 (1956)].
  6. Ostrogovich, Atti accad. Lincei, [5] 20, I, 185 [C. A., 5, 2099 (1911)];
  7. Birtwell, J. Chem. Soc., 1952, 1279.
  8. Reference 6a, p. 252.
  9. Rackmann, Ann., 376, 181 (1910).
  10. Mackay (to American Cyanamid Co.), U. S. pat. 2,527,314 [C. A., 45, 2513 (1951)].

Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)


potassium carbonate (584-08-7)

ammonia (7664-41-7)

Benzamidine hydrochloride (1670-14-0)

benzonitrile (100-47-0)

benzoyl chloride (98-88-4)

potassium hydroxide (1310-58-3)

piperidine (110-89-4)

cellosolve (107-21-1)

urea (57-13-6)

s-Triazine, 2,4-diamino-6-phenyl- (91-76-9)

methyl Cellosolve (109-86-4)

melamine (108-78-1)

biguanide acetate

biguanide sulfate

guanidine benzoate