Ammonia → Triammonium citrate dextrose

Participants

Reaction Steps

Aqueous triammonium citrate-dextrose (1:6) binders were prepared by the following general procedure: Powdered dextrose monohydrate (915 g) and powdered anhydrous citric acid (152.5 g) were combined in a 1-gallon reaction vessel to which 880 g of distilled water was added. To this mixture were added 265 g of 19% aqueous ammonia with agitation, and agitation was continued for several minutes to achieve complete dissolution of solids. To the resulting solution were added 3.3 g of SILQUEST A-1101 silane to produce a pH˜8-9 solution (using pH paper), which solution contained approximately 50% dissolved dextrose monohydrate and dissolved ammonium citrate solids (as a percentage of total weight of solution); a 2-g sample of this solution, upon thermal curing at 400° F. for 30 minutes, would yield 30% solids (the weight loss being attributed to dehydration during thermoset binder formation). Where a silane other than SILQUEST A-1101 was included in the triammonium citrate-dextrose (1:6) binder, substitutions were made with SILQUEST A-187 Silane, HYDROSIL 2627 Silane, or Z-6020 Silane. When additives were included in the triammonium citrate-dextrose (1:6) binder to produce binder variants, the standard solution was distributed among bottles in 300-g aliquots to which individual additives were then supplied.

Provenance & Evidence