Complex sentence: In many applications (especially pharmaceutical), the use of "n"-hexane is being phased out due to its long term toxicity, and often replaced by n-heptane, which will not form the toxic metabolite hexane-2,5-dione.
Split into simpler sentences: In many applications (especially pharmaceutical), the use of "n"-hexane is being phased out due to its long term toxicity. It is often replaced by n-heptane, which will not form the toxic metabolite hexane-2,5-dione.