TAKE THIS AS AN EXAMPLE:

An oven-dried, 3-L, three-necked flask equipped with a mechanical stirrer, a Friedrich condenser,
and a nitrogen-inlet tube is flushed with nitrogen, and then charged with a suspension of lithium
aluminum hydride (47.9 g, 1.26 mol) in 1200 mL of tetrahydrofuran (THF) (Note 1). The mixture is
cooled (10°C, ice bath) and L-valine (100 g, 0.85 mol) is added in portions over a 30-min period from a
200-mL round-bottomed flask connected to the reaction flask via a flexible plastic sleeve so as not to
produce too vigorous an evolution of hydrogen (Note 2). After the addition is complete, the plastic
sleeve is replaced by a stopper, the ice bath is removed, and the reaction mixture is warmed to room
temperature and then refluxed for 16 hr. The reaction mixture is then cooled again (10°C, ice bath) and
diluted with ethyl ether (1000 mL) (Note 3). The reaction is quenched over a 30-min period with water
(47 mL) (Caution! See (Note 4), aqueous 15% sodium hydroxide (47 mL, over 20 min), and water (141
mL, over 30 min). The solution is stirred for 30 min and the white precipitate is filtered. The filter cake
is washed with ethyl ether (3 × 150 mL) and the organic filtrates are combined, dried with anhydrous
sodium sulfate, and concentrated under reduced pressure，

什么反应要40度反应3天再说你淬灭前监控反应了吗？没有这个信息，根本无从推测是根本就没生成产物还是产物在后处理时丢了或坏了。