ADAMANTANE AND DIAMANTANE - PHASE-DIAGRAMS, SOLUBILITIES, AND RATES OF DISSOLUTION

Properties of adamantane and diamantane relevant to their occurrence i n and removal from gas pipelines have been determined. The phase diagr ams for these two diamondoids have been determined between ambient tem perature and the estimated critical point using vapor pressure measure ments, S-S and S-L phase transition observations, and solubilities in dense carbon dioxide. Diamantane exhibited three different solid phase s. Although many common organic liquids were strong solvents for adama ntane and diamantane, cyclohexane was particularly effective due to th e similarity between its structure and the fused cyclohexane ring stru cture of the diamondoids. A generalized correlation for the mass trans fer coefficient governing the dissolution of extremely thick diamantan e deposits from the inner wall of pipelines developed in this study ca n be used to provide accurate estimates of the amount of solvent requi red to remove the deposit. Reasonable estimates can also be obtained w ith the analytical solution derived in this study if an invariant, ave rage mass transfer coefficient is used.