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A preparation method of free formaldehyde-free and storage-stable sodium bisulfite formaldehyde
The article discloses a preparation method of free formaldehyde-free and storage-stablerongalite, which comprises the steps of sequentially adding sodium metabisulfite, zinc powder, a catalyst and formaldehyde into a reaction system to obtain asodium formaldehyde sulfoxylate solution.
Polyphenol compounds and desiccant are added to the solution to obtain a uniformly mixed and stable sodium formaldehyde sodium sulfoxylate storage solution, and finally concentrated and dried to obtainthe free formaldehyde-free and storage-stablerongalite.
Sodium formaldehyde sulfoxylate is prepared by adopting a one-step method, and free formaldehyde-free and storage-stablerongalite is obtained by adding a polyphenol compound and silica gel.
Themethod realizes the one-step low-temperature method for preparing therongalite which isnofree formaldehyde and stable in storage, the method reduces the reaction temperature and the reaction time required for preparing theformaldehyde sodium sulfoxylate, saves the energy consumption and the time, improves the production efficiency, reduces the production cost, and the preparedrongalite isno free formaldehyde and greatly improves the storage stability.
The production ofsodium bisulfite formaldehyde by this method consists of three main processes: dissolution reduction addition reaction, solid-liquid separation and evaporation and crystallisation.