โ Scribed by Peterangelo, Stephen C. ;Gschwender, Lois ;Snyder, Carl E. ;Jones, William R. ;Nguyen, QuynhGiao ;Jansen, Mark J.
No coin nor oath required. For personal study only.
Multiply alkylated cyclopentanes (MACs) are replacing heritage (mineral oilโbased) spacecraft lubricants because of their excellent performance and low volatility. While MACs have acquired an increasingly prominent role, soluble additives with similarly low volatility are lacking. In this study, the performance of specially designed candidate highโmolecularโweight/lowโvolatility phosphate additives was compared with the performance of conventional phosphate and lead naphthenate additives currently used in space. The candidate additives were equivalent or superior to the currently used additives in both conventional (atmospheric) and vacuum wear tests. Volatility studies revealed superior candidate additive performance compared with currently used additives. In addition, surface chemical analysis of the wear surfaces provided a better understanding of the antiโwear protective films formed by these additives. Copyright ยฉ 2008 John Wiley & Sons, Ltd.
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Lewis acid promoted intramolecular additions of allylsilanes to I~-lactones proceed smoothly to give variously substituted cyclopentanes. A proposed transition state assembly for this reaction guided our efforts to improve the stereo.selectivity, A novel Fdedel-Cr'dts alkylation of ~-lactones is als