acid sensitivity of the u03b1 hydroxyazo products and the azohydroperoxide starting material it is essential that the ph of the reducing system be at ph 7 or above at the beginning and throughout the reduction aqueous sodium sulfite solution is the most preferred reducing system the concentration of the solution can vary from 1 2 to a saturated solution however the more concentrated the solution the slower it must be added to control the reaction exotherm another suitable reducing system would be hydrogen in the presence of hydrogenation catalysts such as raney nickel platinum on carbon platinum oxide palladium on charcoal etc it would be preferable to run these hydrogenations in the presence of a weak base to prevent acid decomposition of the azo hydroperoxide or u03b1 hydroxyazo surprisingly we have found that this novel method of preparing u03b1 hydroxyazoalkanes also applies to the compounds of the prior art i e i compounds where r 1 would be hydrogen we used this method to prepare four primary alkyl u03b1 hydroxyazoalkanes of the prior art type see table iv for comparison of foaming efficiencies in polyester resins with the novel i compounds the following are examples of novel compounds which fall within the scope of the i azo compounds into a 250 ml 4 neck flask equipped with a magnetic stirrer thermometer condenser and addition funnel was added 0 5 moles of the appropriate ketone the reaction flask was cooled.