New Rare Earth Antiknock Additives that are Potential Substitutes for Tetraethyl Lead.

摘要

Research has demonstrated that certain lanthanide beta-diketonate chelates can function as antiknock agents in gasoline. Many lanthanide beta-diketonate chelate compounds were screened using ASTM knock-rating procedures. Antiknock effectiveness was observed to be a function not only of the particular lanthanide and ligand involved but also highly dependent upon test procedure and fuel type. Tetrakis (2,2,6,6-tetramethyl-3,5-heptanedionato)cerium(IV)Ce(thd)4, was found to be superior in performance to tetraethyl lead as an antiknock agent for gasoline when tested by the Supercharge Method. The significance of this result, compared to the inferior performance of Ce(thd)4 relative to tetraethyl lead observed in all other tests, is examined. A synergistic increase in octane number was observed when certain organic compounds were added to fuel containing Ce(thd)4. The compound was tested additionally in independent studies which included single cylinder and on-the-road V-8 engine tests. Use of novel rare earth additives in place of lead alkyls would result in reduced environmental pollution by lead and possibly other noxious emissions. The results of these investigations are presented and assessed. Topics requiring study or further development are identified.