Sulfuric Acid → 1-Octadecanaminium, N,N-dimethyl-N-octadecyl-, sulfate (1:1)

Participants

Reaction Conditions

Reaction Steps

In a 1 liter 3-necked round bottomed flask equipped with a mechanical stirrer and reflux condenser were suspended 60 grams (90.8 millimoles) of distearyl dimethyl ammonium methylsulfate in a mixture of 168.75 grams of isopropanol and 56.25 grams of deionized water. 9.57 grams of 95 percent sulfuric acid (90.8 millimoles) were then added and the reaction mixture was heated at gentle reflux, at about 820° C., for 4 hours. The resulting clear, orange-yellow solution was then cooled slowly. After about one hour, at about 30° C., crystals started to appear, followed by a massive crystallization with a noticeable exotherm of over 4° C. and the formation of white viscous slurry The crystallization was continued overnight, about 18 hours, under agitation at about 20° to 25° C. The slurry was filtered under vacuum on an 11 centimeter Whatman #4 filter paper with a Buchner funnel. The filtration time recorded was 2 minutes. The excellent filtration rate reflects the excellent crystallization characteristics of the product. A white filter cake was obtained, while a yellowish filtrate was removed. The filter cake was reslurried in 225 grams of a 75/25 mixture of isopropanol and water to remove residual acidity. The mixture of isopropanol and water was used to avoid the formation of gel experienced when water only is used to wash the highly acidic wet cake. A white slurry was obtained, which again required only 2 minutes to filter. Two more reslurry washings were accomplished as described above with filtration times of about 2 minutes each. A final reslurry wash with 200 grams of acetone was accomplished after which the product was recovered by filtration and dried overnight in vacuum at about 50° C. 42.7 grams (72.7 percent yield) of distearyl dimethyl ammonium bisulfate (IR fingerprint) were recovered. Analyticals- melting point (DSC) 94.50° C., H2O content 0.04 percent, bisulfate content (by titration) 15.24 percent.

Provenance & Evidence