Complex sentence: It is produced widely, however, due to its instability and toxicity, most acrolein is reacted to other products immediately after it has been produced, it is described as having a piercing, disagreeable, acrid smell similar to that of burning fat.
Split into simpler sentences: It is produced widely, however, due to its instability and toxicity, most acrolein is reacted to other products immediately after it has been produced. It has a piercing, disagreeable, acrid smell similar to that of burning fat.