Preparation of Trimethylolmelamine under Various Conditions

The same procedure was used for Preparations 2 to 5 (Table X), inclusive, except that the concentration was closer to 50% than 55%, as in the foregoing case, during the trimethylolmelamine stage. Reaction in the presence of the buffer was at 50 1% in all five cases. 

In these two cases it was impractical to operate at 50% concentration throughout the reaction because the high reaction rate leads to gelation. The concentration therefore had to be lowered and the reaction time curtailed. For Preparation 6 the trimethylolmelamine solution was developed in the same way as in Preparation 1, that is, by heating 20 min at 60°C. Two hundred and eighteen grams of the 50% solution (equivalent to 0.5 mole of melamine) was diluted at once with 56.5 ml of water followed by 35.4 gm of 36% hydrochloric acid, held 2 min at 50°C, and then cooled. During reaction with the acid in Preparation 7 as well as 6 the concentration of melamine plus formaldehyde was 35%. 

Jentifi- nation BulTer Sought concen- tration pH Appearance Microscopic appearance Solubility Yield (%) X-Ray diffraction Nitrogen Formalde- hyde (over P2O5) Fusion point ( O Assigned composition 

86 NaOH 0.13 Glycine 0,10 NaCI 13 11.6 11.8 Thick slurry Anisotropic spherulites, particle size 100-50 Mm, no obvious differences Soluble in boiling water 91 Crystalline 39.07 40.0 0.60 152-157 Trirnethylol- melamtne 

67 Na2llF04 0.41 KH2PO4 7 7.6 7,4 Thick slurry Soluble in boiling water 71 Crystalline 39.21 40.7 0.39 155-159  

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