ON-LINE DIAGNOSTICS FOR FULLERENE SYNTHESIS

IT HAS RECENTLY BEEN SHOWN THAT CAGED CARBON CLUSTERS, FULLERENES, ARE PRODUCED IN SIGNIFICANT QUANTITIES IN A CARBON ARC IN A HELIUM ATMOSPHERE AT ABOUT 150 TORR. IT WAS ALSO SHOWN THAT THE FULLERENES ARE SOLUBLE IN COMMON ORGANIC SOLVENTS. THESE TWO IMPORTANT DISCOVERIES OPENED THE DOOR TO SEVERAL POSSIBLE APPLICATIONS OF CARBON FULLERENES. EXAMPLES INCLUDE CERAMIC COATINGS, LUBRICANTS, COATINGS FOR COMPOSITE MATERIALS, MOLECULAR SIEVE CARBONS, CATALYSTS, AND SUPERCONDUCTING FILMS. HOWEVER, FULLERENE YIELDS REPORTED BY DIFFERENT LABORATORIES USING THIS PROCEDURE VARY OVER A LARGE RANGE, FROM LESS THAN 5% TO AS MUCH AS 40% OF THE CARBON SOOT; THE SELECTIVITY FOR C60 ALSO VARIES WIDELY. THE OVER-ALL OBJECTIVE OF THE PHASE I AND PHASE II PROGRAMS IS TO DEVELOP AN OPTIMIZED CARBON ARC PROCESS FOR THE MANUFACTURE OF BULK QUANTITIES OF FULLERENES. THE PHASE I PROGRAM HAS THE FOLLOWING SPECIFIC OBJECTIVES: (1) CONSTRUCTION OF A CARBON ARC REACTOR WITH CONTINUOUS GAS FLOW; (2) EMPLOYMENT OF ON-LINE FOURIER TRANSFORM INFRARED DIAGNOSTICS TO MEASURE SOOT AND GAS SPECIES CONCENTRATION AND TEMPERATURE; (3) STUDY OF HOW VARIATIONS IN THE REACTOR PHYSICS (GEOMETRY, FLUID MECHANICS, HEAT TRANSFER) AFFECT THE SELECTIVITY AND YIELD OF C60 AND OTHER FULLERENES; (4) STUDY OF HOW VARIATIONS IN THE REACTOR CHEMISTRY (ADDITION OF H2, O2, N2, OR PRESENCE OF CONTAMINANTS LIKE H2O OR HYDROCARBONS) AFFECT THE YIELD AND SELECTIVITY OF C60 AND OTHER FULLERENES; (5) DETERMINATION OF A PRELIMINARY, ON-LINE, ULTRAVIOLET-TO-VISIBLE (UV-VIS) SPECTRUM; AND (6) DESIGN OF A MORE OPTIMAL REACTOR SYSTEM THAT WOULD ALLOW ADDITIONAL DIAGNOSTICS (TO BE USED IN PHASE II). IN PHASE II, ADDITIONAL DIAGNOSTIC METHODS (NAMELY, MOLECULAR-BEAM-SAMPLED MASS SPECTROMETRY, UV-VIS, AND LASER SCATTERING) WILL BE USED TO SIGNIFICANTLY IMPROVE THE UNDERSTANDING OF THE CHEMISTRY OF FULLERENE SYNTHESIS TO COMPLETE THE OPTIMIZED PROCESS DESIGN.