| 摘要 |
<p>In a vanillin production process, a liquid mixture containing vanillin and water is extracted with carbon dioxide at a temperature from 0?o to 110o¿C and a pressure from 30 to 400 bar, after which the vanillin is separated. The carbon dioxide-containing vanillin is led at the extraction temperature and pressure through an aqueous solution of sulphite or hydrogen sulphite, this solution is then acidified with sulphuric acid to a pH value between 2 and 4, and the vanillin-free carbon dioxide is returned to the extraction stage.</p> |
