Methods of employing corrosion inhibitors with oxidizing and/or non-oxidizing biocides, such as peroxycarboxylic acids, to provide corrosion protected compositions are disclosed. Various corrosion inhibitors further provide biocidal efficacy in addition to the corrosion protection providing further benefits for application of use. Methods of employing corrosion protected biocide compositions, such as peroxycarboxylic acid compositions, for corrosion protection are particularly well suited for treating fluids intended to flow through pipes, namely in the energy industry, water and paper industries, etc. Methods providing suitable corrosion protection in comparison to untreated systems and corrosion protected systems using conventional corrosion inhibitors, such as quaternary amines and imidazolines commonly used in the industry, are disclosed.

Methods of employing corrosion inhibitors with oxidizing and/or non-oxidizing biocides, such as peroxycarboxylic acids, to provide corrosion protected compositions are disclosed. Various corrosion inhibitors further provide biocidal efficacy in addition to the corrosion protection providing further benefits for application of use. Methods of employing corrosion protected biocide compositions, such as peroxycarboxylic acid compositions, for corrosion protection are particularly well suited for treating fluids intended to flow through pipes, namely in the energy industry, water and paper industries, etc. Methods providing suitable corrosion protection in comparison to untreated systems and corrosion protected systems using conventional corrosion inhibitors, such as quaternary amines and imidazolines commonly used in the industry, are disclosed.

The present invention relates generally to methods for forming peroxyformic acid, comprising contacting formic acid with hydrogen peroxide. The methods for forming peroxyformic acid can include adding formic acid with a relatively lower concentration of hydrogen peroxide, or adding formic acid to a peroxycarboxylic acid composition or forming composition to react with hydrogen peroxide in the compositions. The present invention also relates to peroxyformic acid formed by the above methods. The present invention further relates to the uses of peroxyformic acid for treating a variety of targets, e.g., target water, including target water used in connection with oil- and gas-field operations. The present invention further relates to methods for reducing or removing H.sub.2S or iron sulfide in the treated water source, improving clarity of the treated water source, or reducing the total dissolved oxygen or corrosion in the treated water source, using peroxyformic acid, including peroxyformic acid generated in situ.

The present invention relates generally to methods for forming peroxyformic acid, comprising contacting formic acid with hydrogen peroxide. The methods for forming peroxyformic acid can include adding formic acid with a relatively lower concentration of hydrogen peroxide, or adding formic acid to a peroxycarboxylic acid composition or forming composition to react with hydrogen peroxide in the compositions. The present invention also relates to peroxyformic acid formed by the above methods. The present invention further relates to the uses of peroxyformic acid for treating a variety of targets, e.g., target water, including target water used in connection with oil- and gas-field operations. The present invention further relates to methods for reducing or removing H.sub.2S or iron sulfide in the treated water source, improving clarity of the treated water source, or reducing the total dissolved oxygen or corrosion in the treated water source, using peroxyformic acid, including peroxyformic acid generated in situ.

A method to reduce or eliminate N-heterocycles, the method providing one or more environmentally benign chelators (EBCs) to an aqueous cooling system, the aqueous cooling system having at least one N-heterocycle in the presence of a halogenating or non-halogenating oxidizer. A method to reduce or eliminate AOX, the method providing one or more environmentally benign chelators (EBCs) to an aqueous cooling system, the aqueous cooling system having at least one AOX-containing species in the presence of a halogenating biocide.

A method to reduce or eliminate N-heterocycles, the method providing one or more environmentally benign chelators (EBCs) to an aqueous cooling system, the aqueous cooling system having at least one N-heterocycle in the presence of a halogenating or non-halogenating oxidizer. A method to reduce or eliminate AOX, the method providing one or more environmentally benign chelators (EBCs) to an aqueous cooling system, the aqueous cooling system having at least one AOX-containing species in the presence of a halogenating biocide.

Compositions may include a corrosion inhibitor including a heterocyclic diamine prepared from the reaction of an alkyl diamine and an aldehyde, wherein the alkyl diamine has the general formula: R4NH(CH.sub.2).sub.nNHR5, where n is an integer between 3 and 6, and R4 and R5 are independently hydrogen or a C2-C30 saturated or unsaturated hydrocarbon radical. Methods may include contacting a metal surface with a corrosion inhibitor composition, wherein the corrosion inhibitor includes a heterocyclic diamine corrosion inhibitor from the reaction of an alkyl diamine and an aldehyde, wherein the alkyl diamine has the general formula: R4NH(CH.sub.2).sub.nNHR5, where n is an integer between 3 and 6, and R4 and R5 are independently hydrogen or a C2-C30 saturated or unsaturated hydrocarbon radical.

A corrosion inhibitor composition, which includes (i) a date palm leaves extract, (ii) a benzimidazole compound having at least one a carbamate group, (iii) a pyridine compound, (iv) a thiourea compound, (v) a cinnamaldehyde compound, (vi) a metal iodide, (vii) urotropin, and (viii) a base fluid containing an alcohol and an organic acid. A method of inhibiting corrosion of metal during acid cleaning is also disclosed, whereby the metal is treated with an acidic treatment fluid containing 1 to 5 wt. % of an acid, based on a total weight of the acidic treatment fluid, and 0.1 to 5 vol. % of the corrosion inhibitor composition, based on a total volume of the acidic treatment fluid.

Described herein are the methods of using a cationic alkyl polyglycoside in a corrosion control composition to reduce corrosion for metal surfaces in a water system. The described methods or compositions are found to be effective than those methods or compositions including commonly used corrosion inhibitors for water systems.

A method of making cerium citrate includes combining cerium carbonate and citric acid to produce cerium citrate and carbon dioxide. The cerium citrate is substantially free of negative ions other than citrate. The cerium citrate can be used in a corrosion inhibitor composition.