Thermal decomposition of some uranium cyclopentadienyl and cyclooctatetraene compounds

Thermal decomposition of metalloorganic compounds (MOC) of uranium, such as (C5H5)4U, (C5H5)3UCl, (CH3C5H4)3UCl, (C8H8)2U and (n-C4H9C8H7)2U has been studied using thermogravimetric method as well as by means of thermolysis in quasiflow system of the first one at the temperature 500 deg C, of the rest at 420, 300, 400 and 200 deg C respectively with the determination of decomposition products using the method of gas-liquid chromatography and element analysis. It is established that the break-off of the organic part of (C5H5)4U molecules proceeds in three stages, starts at the temperature of about 200 deg C and ends at approximately 1000 deg C, of the molecules (C5H5)3UCl, (CH3C5H4)UCl, (C8H8)2U and (n-C4H9C8H7)2U - in one stage at the temperatUres of approximately 390, 270, 370 and 170 deg C respectively. Thermal stability of the MOC stUdied decreases in the sehies (C5H5)4U > (C5H5)3UCl >= (C8H8)2U > (CH3C5H4)3UCl > (n-C4H9C8H7)2U. In thermolysis products of uranium cyclopentadienyl compounds hydrogen, methane, cyclopentadiene, dicyclopentadiene, styrene and alkylbenzenes are found, and in the case of (n-C4H9C8H7)2U butane and butylcyclooctatetraene are additionally formed. Solid phase contained uranium, hydrocarbon residue depleted in hydrogen and, in the case of MOC chlorine derivatives-chlorine. The results obtained point to the catalytic character of uranium MOC thermal decomposition process, in which ligand break-off is accompanied by their sesecondary transformations