Based on a 1936 patent (Re: Reichspatentamt Patentschrift Nr 623821 Klasse 12p Gruppe 14)

Original:

"5 grams morphine was dissolved in 50 ml of alcohol and after the addition of 0.5g of palladium black, the mixture was refluxed for 4 hours. After the catalyst was filtered off and the solution concentrated, dihydromorphinone crystallized. Yield 3 grams."

Downscaled to 1/5th; 1g Morphine Hcl dissolved in 10ml anhydrous Ethanol, 100mg palladium black added, mixture refluxed for 1 hour. Palladium black filtered off, solution concentrated, Dilaudid crystallized, expected yield 600mg Hydromorphone (Dihydromorphinone).

Viable with the downscaling?

Recommended temp. for direct rearrangement of morphine to Dilaudid in alcoholic solution in presence of Palladium catalyst? Has to be low enough not to degrade the Morphine or Hydromorphone, but hot enough to facilitate the reaction. Tips?

How about 78oC...?

;)

http://designer-drug.com/pte/12.162.180.114/dcd/chemistry/dihydromorphinones.html

Yep, see examples toward the bottom for evidence that it works in significantly scaled down rxns. And yes, gentle reflux is good. :) This thread has been done before by the way; a forum search would have probably solved your questions.