Reclaimed Oxidation Stability

Comparison of the oxidation stability of virgin oils, reclaimed oils, and S3mthetic lubrication oils. 

It was described earlier that the interaction between radical anions and ketones in a partially oxidized, PCB contaminated oil, produces alcohols. It would therefore be expected that the formation of aromatic alcohols in particular would give rise to natural oxidation inhibitors. It is very likely that the effectiveness of the inhibitors formed in this way is small, relative to DBPC but, in any case, the oil should not be deleteriously affected by the treatment provided that the reclaimed oil has DBPC added to it. The oxidation stability of the processed oil should then be as good as, or possibly better than, new oil. Experimental data have shown that the oxidation stability of oils treated by the MOP system are the same as new oil by ASTM D2112. 

In a synthesis of the immunosuppressant Sanglifehrin A, two hydroxyl groups and a ketone were mutually protected as an acetal [Scheme 1.33].60 The ketone was generated by a Wacker oxidation of the terminal alkene 33.1 whereupon it was immediately converted to the bicyclic acetal 33.2 on treatment with acid. The acetal 33.2 survived the many steps required to elaborate the complex intermediate 33.3 but its stability was to exact a price the synthesis languished on the cusp of completion until conditions were found to hydrolyse the acetal without insult to the remaining delicate functionality. Hie three functional groups were eventually reclaimed in a modest 33% yield by interrupting the hydrolysis at 50% completion. 

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