Monolefins such as ethylene are reacted with ammonia using alkali metal amide catalysts such as cesium or rubidium amides, or low melting mixtures of amides such as cesium/potassium, cesium/sodium or sodium/potassium amides. Conversions are improved compared to reactions using sodium or potassium amide alone. Conversions of ethylene are improved also when liquid ammonia is present.