Volatile Rare Earth Chelates

Abstract

Here again, diadsorbed seems preferable to complex,6 but good evidence supports surface intermediates which resemble -bonded diene and allyl.3-6We suggest that bicyclononane-dio and -d\% result from exchange of h,h and g,g. Adamantane (bicyclononane with carbon atoms 3 and 7 bridged by methylene) exchanges only one hydrogen atom per period of adsorption. Since all of its vicinal hydrogen atoms are rigidly staggered, this accords with predictions.2 Accordingly, the atoms at carbon atom 9 in bicyclononane will not exchange in conjunction with others barring some transannular reaction. In exchange of 1,1,3,3tetramethylcyclohexane on palladium,7 there is a maximum at da in addition to one at d¡ which results from alternation between A and B. Formation of bicyclononane-dio and -du is consistent with the proposal7 that dw in cyclopentane and d-a in tetramethylcyclohexane result from alternation between -bonded olefin and -bonded allyl. This cannot exchange h' and g'.These experiments were run in a flow apparatus with 5% palladium-on-alumina catalyst2 previously reduced in hydrogen at 350°. The partial pressures were cyclopentane, 93 mm.; bicyclononane, 8 mm.; adamantane, 5 mm.; and deuterium to 1 atm.Acknowledgment. This work was supported by the Petroleum Research Fund of the American Chemical Society, Grant 1579-C. We thank Dr.

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

“…The so lution of Na(thd) thus formed was stirred for approximately fifteen minutes (the.. solution is a light yellow color). Next the (NH 4 )2Ce(NO 3 ) 6 solution was added to the Na(thd solution dropwise with stirring. The color of the resulting solution immediately turned dark red-brown, and a small amount of Ce(thd)4 precipitated at this point.…”

“…A general method which has been reported previously [6][7][8][9][10][11] was used to prepare the individual tris lanthanide-thd chelates. This method is capable of producing the individual chelates in ca.…”

“…distilled water. The solution was stirred and fifty millimoles of (NH4)2Ce(N0 3 ) 6 (Matheson, Coleman, and Bell), 27.4 grams, dissolved in 75 c.c. distilled water was added.…”

“…Elemental Analysis for Ce(tdh) 4 Calculated (%) Found (%) 6 (Matheson, Coleman, and Bell), 4.13 grams, dissolved in absolute ethanol was added to the continuously stirred solution. A dark brown color appeared in the solution upon the addition of the ceric solution.…”

“…In general, compounds of the cerium group elements appear to be less toxic than those of the yttrium group elements [4,5,6]. This generalization appears to be true not only for oral toxicity but for inhalation toxicity as well.…”