Insights into the dissolution mechanisms of detergent agglomerates: An approach to assess dissolution heterogeneity

- The dissolution rates of NaLAS and Na2CO3 are time-dependent.
- NaLAS belongs to IDR, whereas Na2CO3 follows DDR and IDR for type 1 and type 2.
- The dissolution heterogeneity is influenced by the type and content of binder.
- The two types of detergent agglomerates follow different dissolution mechanisms.

In this work, the dissolution mechanisms of detergent agglomerates with different binders were investigated in aqueous solution. The dissolution processes of detergent agglomerates were online monitored by using in situ UV-VIS spectrophotometer and electric conductivity probe. Dissolution profiles were correlated by Weibull model to evaluate the time-dependent dissolution rate coefficient and to classify the type of dissolution rate function kt(t). The Kullback-Leibler information distance dK-L was proposed to assess the degree of dissolution heterogeneity. The results indicate that the sodium linear alkylbenzene sulfonates (NaLAS) and sodium carbonates (Na2CO3) in detergent agglomerates have different dissolution behaviors, and their dissolution rates are influenced by the type and content of binders. Moreover, detergent agglomerates using semi-solid NaLAS paste or liquid linear alkylbenzene sulfonic acid (HLAS) as binders in granulation processes follow different dissolution mechanisms in water.

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