Hydrazones as oxygen scavengers in boiler water systems
AssigneeNalco Chemical Company
InventorsDouglas G. Kelley, Deborah M. Rogers
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Abstract
A method of removing dissolved oxygen from boiler water having and alkaline pH is disclosed. The method uses at least one hydrazone compound of one of the following formulae: ##STR1## wherein R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are independently selected from hydrogen, C.sub.1 -C.sub.16 alkyl, aryl, substituted alkyl or substituted aryl, and R.sup.5 and R.sup.6 are independently selected from hydrogen, C.sub.1 -C.sub.16 alkyl, aryl, substituted alkyl, or substituted aryl, ##STR2## Preferably, an oxidation-reduction catalyst such as Cu(II) is used as well. The hydrazones used in the present invention are highly shelf stable and do not suffer the toxicity of hydrazine.
Claims9
A method for removing dissolved oxygen from boiler water having an alkaline pH which comprises adding to the boiler water an oxygen scavenging amount of at least one dihydrazone compound selected from the group consisting of glyoxaldihydrazone (H.sub.2 N--N.dbd.CH--HC.dbd.N--NH.sub.2), pyruvaldehyde dihydrazone (H.sub.2 N--N.dbd.CCH.sub.3 --CH.sub.3 C.dbd.N--NH.sub.2) and biacetyl dihydrazone (H.sub.2 N--N.dbd.CCH.sub.3 --CH.sub.3 C.dbd.N--NH.sub.2).
A method of removing dissolved oxygen from boiler water having an alkaline pH and passivating boiler surfaces, the method comprising the steps of adding to the boiler water at least about 0.5 moles of a dihydrazone compound per mole of dissolved oxygen and about 0.2% to about 20% by weight based on the dihydrazone of a catalyst capable of undergoing oxidation-reduction reactions, wherein the dihydrazone compound is selected from the group consisting of glyoxaldihydrazone (H.sub.2 N--N.dbd.CH--HC.dbd.N--NH.sub.2), pyruvaldehyde dihydrazone (H.sub.2 N--N.dbd.CCH.sub.3 --CH.sub.3 C.dbd.N--NH.sub.2) and biacetyl dihydrazone (H.sub.2 N--N.dbd.CCH.sub.3 --CH.sub.3 C.dbd.N--NH.sub.2).
Dependencies are inferred from the claim text.