N - hydroxyethylpyrrolidone ( NHP ) was synthesized from � � - butyrolactone and ethanolamine on Y molecular sieve catalyst by two steps.以改性Y分子筛为催化剂,γ-丁内酯和乙醇胺为原料,采用γ - 丁内酯法两步合成N - 羟乙基吡咯烷酮 ( NHP )....
蜜蜂在鲜红的罂粟花和艳紫的蓟草花之间飞舞嗡嗡低吟.Bees moved , humming thoughtfully , from scarlet poppy to purple thistle.微风吹到平台时,棕榈叶片发出簌簌的低吟.When these breezes reached the platform the palm - fronds would whisper.轮胎在公路上嚓嚓低吟.The tires sang over...