4-alkyl and aryl semicarbazides as oxygen scavengers
AssigneeNalco Chemical Company
InventorBruce R. Bailey
Life of this patent
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Abstract
A method for removing dissolved oxygen from alkaline water containing dissolved oxygen at a temperature greater than 250.degree. F. which comprises the step of: adding to said alkaline water containing dissolved oxygen an effective oxygen-scavenging amount of a water-soluble semicarbazide of the formula ##STR1## wherein R.sub.1 and R.sub.2 are selected from the group consisting of C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy and alkyloxy groups. Preferred materials are 4-phenyl semicarbazide, 4-isopropyl semicarbazide, 4-4-diethyl semicarbazide and carbazoyl morpholine. Below 400.degree. F., a catalyst is also required.
Claims44
A method for removing dissolved oxygen from alkaline water containing dissolved oxygen at a temperature greater than 400.degree. F. which comprises the step of:
- adding to said alkaline water containing dissolved oxygen an effective oxygen-scavenging amount of a water-soluble semicarbazide of the formula ##STR8## wherein R.sub.1 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy and alkyloxy groups, and R.sub.2 is selected from the group consisting of hydrogen, and C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy, and alkyloxy groups.
A method for removing dissolved oxygen from alkaline water containing dissolved oxygen at a temperature from about 250 to about 400.degree. F. which comprises the step of adding to said alkaline water containing dissolved oxygen
- a) an effective oxygen-scavenging amount of a water soluble semicarbazide of the formula ##STR9## wherein R.sub.1 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy and alkyloxy groups, and R.sub.2 is selected from the group consisting of hydrogen, and C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy, and alkyloxy groups;
- and
- b) an effective catalyzing amount of a catalyst capable of undergoing oxidation-reduction reactions selected from the group consisting of copper, cobalt, manganese, nickel, hydroquinone and combinations thereof.
A method for removing dissolved oxygen from alkaline water containing dissolved oxygen at a temperature greater than 400.degree. F. which comprises the step of:
- adding to said alkaline water containing dissolved oxygen an effective oxygen-scavenging amount of a water-soluble semicarbazide of the formula ##STR10## wherein R.sub.1 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy and alkyloxy groups, and R.sub.2 is selected from the group consisting of hydrogen, and C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy, and alkyloxy groups;
- and an effective neutralizing amount of a neutralizing amine.
A method for removing dissolved oxygen from alkaline water containing dissolved oxygen at a temperature from about 250 to about 400.degree. F. which comprises the step of adding to said alkaline water containing dissolved oxygen
- a) an effective oxygen-scavenging amount of a water soluble semicarbazide of the formula ##STR11## wherein R.sub.1 is selected from the group consisting of C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy and alkyloxy groups, and R.sub.2 is selected from the group consisting of hydrogen, and C.sub.1 -C.sub.10 alkyl, cycloalkyl, aryl, cycloalkyloxy, and alkyloxy groups;
- b) an effective catalyzing amount of a catalyst capable of undergoing oxidation-reduction reactions selected from the group consisting of copper, cobalt, manganese, nickel, hydroquinone and combinations thereof;
- and
- c) an effective neutralizing amount of a neutralizing amine.
Dependencies are inferred from the claim text.