Azines, e.g., ketazines, are continuously produced by (i) establishing a loop having an azine reaction medium circulating therein, such loop including an azine reaction zone, means for separating azine final product from the circulating reaction medium, means for heating the reaction medium and for purging water therefrom, and means for recycling heated and purged reaction medium to the azine reaction zone, (ii) introducing hydrogen peroxide, ammonia and a carbonyl compound into the circulating reaction medium in the azine reaction zone, (iii) withdrawing azine final product thus formed from the circulating reaction medium. downstream of the azine reaction zone, (iii) thereafter purging water from the circulating reaction medium to maintain the volume thereof essentially constant, (iv) heating the circulating reaction medium to a temperature of at least 130° C., (v) recycling thus heated reaction medium to the azine reaction zone, and (vi), at any point along the loop, introducing a reagent into the circulating reaction medium as to essentially maintain the equilibrium of the azine-forming reaction; the final product azines are conveniently hydrolyzed into hydrazine hydrate.