text: Thermal rearrangements of aromatic hydrocarbons are generally carried out through flash vacuum pyrolysis (FVP). In a typical FVP apparatus, a sample is sublimed under high vacuum (0.1-1.0 mmHg), heated in the range of 500-1100 °C by an electric furnace as it passes through a  horizontal quartz tube, and collected in a cold trap. Sample is carried through the apparatus by nitrogen carrier gas.
  FVP has numerous limitations: 
  *First, it requires a slow rate of sublimation to minimize bimolecular reactions in the gas phase, limiting the amount of material that can be reacted in a given amount of time.
  *Second, the high temperatures used in FVP often lead to reactant or product degradation. Combined, these first two limitations restrict FVP yields to the range of 25-30%.
  *Third, the high temperatures used in FVP do not allow for the presence of functional groups, thereby limiting possible products.
  *Fourth, as FVP is a gas-phase process, difficulties are frequently encountered when scaling above the milligram level.
  *Fifth, the FVP synthesis of strained systems mandates temperatures exceeding 1100 °C, which can lead to the degradation and softening of the expensive quartz apparati.