Complex sentence: Presence of DBZP is a marker for low quality or badly made BZP, it can be made as a reaction byproduct during BZP synthesis, either because the reaction has been run at too high a temperature, or because an excess of benzyl chloride has been used.
Split into simpler sentences: Presence of DBZP is a marker for low quality or badly made BZP. It can be made as a reaction byproduct during BZP synthesis, either because the reaction has been run at too high a temperature, or because an excess of benzyl chloride has been used.