| 摘要 |
What is claimed is a process for preparing amino- or hydroxybenzonitriles, in which, in the course of an ammonolysis, the corresponding amino- or hydroxybenzoic acid compounds are reacted with ammonia in the presence of a supported catalyst comprising phosphate at temperatures between 250° C. and 500° C. The actual preparation step is performed in a reaction gas (mixture) and without involvement of an organic solvent, and is followed by an at least 2-stage purification step. In this purification step, the gaseous mixture obtained from the preparation step is first converted to an aqueous basic suspension and then the product present in the solid is released from this suspension. The main advantage of this combination process is that the starting materials are not esters, which is why the resulting products, in contrast to the processes which are otherwise customary, are free of the by-products which are otherwise customary, which leads to a high product purity. The process claimed can additionally be performed in an extremely economically viable manner, since the end product and the by-products are present in different states of matter in the suspension used and can therefore be separated easily from one another. In this way, solvent-free amino- or hydroxyl-containing benzonitriles are obtained in high yield and significantly improved product quality.
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