Aluminium sulfacetate is a mixture ofaluminium salts dissolved in water with formulaAl
2SO
4(CH
3CO
2)
4.[1][2]
It is an evenly balanced mixture ofaluminium sulfate andaluminium acetate. It can be used as amordant, which is a substance used to setdyes on fabrics[3] that typically contains apolyvalent metal ion like aluminium or iron,[4] In mixtures withbasic aluminium diacetate or aluminium sulfacetate, aluminium triacetate has been used as a mordant withalizarin dye.[1] In 1899, Albert Ganswindt recommended that the use of impure sulfacetates that are empyreumatic liquids "should be abandoned" in favour of pure preparations.[5]Empyreuma is an obsolete chemical and medical term referring to "the smell and taste associated with burning vegetable and animal matter",[6] and likely results in this case from the use ofpyroligneous acid (wood acid) or wood acid lime in the preparation of the mordant.[5]
A common approach to preparing aluminium sulfacetate is by reaction of aluminium sulfate withlead(II) acetate. The relative amount of each reagent controls the composition of the resulting mixture.[1] When thestoichiometric ratio of lead acetate to aluminium sulfate exceeds 3:1, the process is theoretically driven to completion and aluminium triacetate is the sole product. With less lead acetate, a mixture of aluminium triacetate and aluminium sulfacetate results that becomes increasingly rich in the latter as the reagentmole ratio approaches 2:1. This approach is used to form various mixtures for mordant applications:[1]
Basic aluminium sulfacetates can also be prepared,Al
2SO
4(CH
3CO
2)
4 -n(OH)
n, withhydroxide anions replacing someacetate ions. The extreme cases are aluminium sulfacetate itself (n = 0) and the double salt of aluminium sulfate andaluminium hydroxide (n = 4 case,Al
2SO
4(OH)
4). Aluminium sulfacetate is made from thehydrates of aluminium sulfate and lead acetate:[2]
Then = 1 andn = 2 cases, both of which are basic aluminium sulfacetates, are prepared usingsodium bicarbonate along with the regents:[2]
Then = 3 case, also a basic aluminium sulfacetate, is prepared usingacetic acid instead of lead acetate, along with sodium bicarbonate:[2]
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