Formaldehyde → Bronopol

An aqueous formaldehyde solution, 37% by weight H2CO, containing 75.81 g. aldehyde (0.934 mole) was adjusted to pH 6.5 with 0.5 M aqueous sodium bicarbonate. The entire reactor was placed in a room temperature water bath, and 65.29 g. bromonitromethane (0.467 mole) was added, with vigorous stirring, at such a rate that the reagent was immediately consumed. Aqueous sodium bicarbonate was added to the mixture by a pH-controlled feed pump so that the reaction zone pH was constantly maintained at a level between 6.0 and 6.4. When the bromonitromethane charge was complete, the temperature of the reaction mixture was elevated to 45° C. and held there for 1-12 hours, with constant stirring. The pH of the mixture was maintained in the preset range of 6.0 to 6.5 by the pH-controlled base feed. At the end of the heated stir time, the solution was allowed to cool to room temperature, whereupon the desired product precipitated as a crystalline solid, which was isolated by vacuum filtration. The yield of product was 86.8 g. (93%), with a purity assay of 99.8% (by GC of a derivatized sample).

1. customwas placed in a room temperature
2. customat such a rate that the reagent was immediately consumed
3. additionAqueous sodium bicarbonate was added to the mixture by a pH-controlled feed pump so that the reaction zone pH
4. temperaturewas constantly maintained at a level between 6.0 and 6.4
5. additionWhen the bromonitromethane charge
6. customwas elevated to 45° C.
7. temperatureThe pH of the mixture was maintained in the preset range of 6.0 to 6.5 by the pH-controlled base feed
8. customprecipitated as a crystalline solid
9. customwhich was isolated by vacuum filtration

ORD record

ord-29fb565b9b8b42239cdc3c7b1b52c6b6

Source dataset

uspto-grants-1991_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05075510