Benzoic acid itself, ammonium benzoate and sodium benzoate are all administered internally in doses of from five to thirty grains.
But the most important fact is that ammonium benzoate is largely used - often in combination with urinary anodynes such as tincture of hyoscyamus - as a urinary antiseptic in cases of cystitis (inflammation of the bladder) and pyelitis (inflammation of the pelvis of the kidney).
The resulting benzoylazoimide is easily hydrolysed by boiling with alcoholic solutions of caustic alkalis, a benzoate of the alkali metal and an alkali salt of the new acid being obtained; the latter is precipitated in crystalline condition on standing.
An alternative method consists in converting it into ethyl benzoate by shaking with benzoyl chloride and caustic soda.
Benzamide, C 6 H 5 CONH 2, is prepared by the action of benzoyl chloride on ammonia or ammonium carbonate, or from ethyl benzoate and ammonia.