| 摘要 |
The mixtures derive from the oxidn. of cyclohexanol and/or cyclohexanone with HNO3 in the presence of catalysts. The main portion of the adipic acid present is crystallised out, the HNO3 soln. is evaporated, the residue is vapourised, the succinic acid is dehydrated to succinic anhydride, the glutaric acid to glutaric anhyd. and the anhydrides are distilled. The above residue is vapourised at normal press. with an inert gas stream at 200-500 degrees C, the vapour is led, at normal press., over a large surface area suitable silicic acid-containing material at 200-300 degrees C esp. 220-260 degrees C and the resulting prod. is fractionated. The top fraction is separated into glutaric acid and succinic anhydride by a 2nd fractionation after condensation and sepn. of the inert gas. The residue of the 1st fractionation and the metal containing residue from the vapourisation with the inert gas are dissolved in HNO3 and the resulting, optionally filtered, soln. is returned to the HNO3-oxidn. Advantages are economy and high yields.
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