Acetate → Calcium Acetate

Beteiligte Stoffe

Reaktionsschritte

This invention relates to a process for recovering calcium formate, propionate or acetate from biomass. According to the invention, a cellulose-, hemicellulose- or starch-containing biomass is subjected to rapid pyrolysis to obtain a crude product containing an aqueous phase and an organic phase. The product obtained, preferably as the aqueous phase, is then distilled to produce a distillate containing at least one acid selected from acetic acid, formic acid and propionic acid as well as their esters and formaldehyde. An alkaline source of calcium is added to this distillate to adjust the pH to an alkaline level sufficient to hydrolyze the esters, cause at least partial oxidation of the formaldehyde and prevent volatilization of acetate, formate or propionate ions as acetic acid, formic acid or propionic acid respectively. For this purpose, the pH is adjusted to a level sufficient to prevent volatilization of acetate, formate or propionate as acetic acid, formic acid or propionic acid respectively. The pH is preferably above 7, but preferably sufficiently low as to avoid residual unreacted alkaline calcium in the calcium salt. A pH range of 7.8 to 8.0 is particularly preferred. This pH adjusted alkaline liquid is then subjected to a further distillation to remove water and volatile organic components and produce at least one of calcium acetate, calcium formate and calcium propionate as solid residue.

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