| 摘要 |
<p>Process for the preparation of 1,1-cyclohexane-diacetic acid (CHDAA) from 1,5-dicarbonitrile-2,4-dioxo-3-azaspiro[5,5]undecane (the imide), by reacting it with sulfuric acid in two steps. The first step at a temperature lower than 100°C and the second step at a reaction temperature from 160 to 190°C. The first step is carried out by dissolving the imide in aqueous sulfuric acid at temperatures from about 65°to about 85°C and then cooling the solution thus obtained to room temperature. The second step is carried out by reacting said solution with aqueous sulfuric acid at temperatures of about 170°C.</p> |
