Corrosion inhibitors organic based

Metal- Working and Hydraulic Fluids. In the preparation of fluids for metal-working and hydrauflcs, the trend has been to replace organic-based materials with aqueous-based materials. Neodecanoic acid has found apphcation in these newer fluids as a corrosion inhibitor and a viscosity improver. For example, neodecanoic acid is used in an aqueous hydrauflc fluid concentrate for corrosion inhibition and improved antiwear properties (101), in the preparation of a thickened aqueous hydrauflc fluid to reduce viscosity loss (102), and in a water-soluble metal working oil to reduce corrosion (103). In a similar vein, neodecanoic acid has been used in antifreeze concentrates for corrosion inhibition (104). 

Where water softening is provided and there is no reduction in system water TDS, treatments are primarily based on inorganic corrosion inhibitor blends (nitrite, molybdate, etc.). Under these circumstances, there is no benefit in using an expensive organic oxygen scavenger to keep the TDS level low, and a common chemical such as catalyzed sodium sulfite may be used. 

Although azoles are commonly thought of as only yellow metal inhibitors, they are, in fact, used for corrosion inhibition in a wider range of metals such as steel and aluminum. They also are often incorporated in molybdate-based programs to both provide some synergism and reduce the level of molybdate required. Azoles also are employed in many types of organic-based formulations, where they improve the overall protection of steel and reduce the risk of corrosion of yellow metals due to the corrosive action of some common phosphonates. 

Certain compounds which have the ability to film or adsorb onto a metal surface are effective at improving fuel lubricity performance. These compounds include modified fatty acids, modified fatty amines, and other amine=based compounds. For years, the lubricity performance of jet fuel has been improved by treatment with organic acid based corrosion inhibitors. 

When fuel processing involves washing with a caustic solution for any reason, some of the caustic may carry over into the finished fuel blend. Carboxylic acid based corrosion inhibitors are very sensitive to the presence of caustic. The acid functionality can react with caustic to form a gel-like organic salt. This material readily accumulates on filters and can eventually plug the filter. 

The 1980s produced a wide range of new copolymers, often using chemistry based on acrylic acid with sulfonic acid, sulfonated styrene, or sulfonated acrylamide. Also, new products were introduced based on phosphinocarboxylic acids. All these modern organic polymers found immediate favor as improved iron dispersants, phosphate stabilizers, or corrosion inhibitors, with good thermal and hydrolytic stability. 

The nature of existing fuels as a complex liquid mixture of hydrocarbons lends itself well to adjustment of properties by choice of fraction, blending, treatment, etc., so that the properties of the fuel can be tailored to meet the demands of particular applications. The fuels are essentially non-polar organic solvents, and readily dissolve a variety of additives. Thus, military fuels can be based on commercial fuels, but with adjusted properties. For example, JP 8 is essentially identical to commercial Jet A-l, but with the addition of a military additive pack to account for the more demanding military requirements. This includes antioxidants to prevent fuel oxidation, metal deactivators to counteract metals, fuel system icing inhibitor to prevent water in fuel from freezing, and a corrosion inhibitor/lubricity enhancer to prevent corrosion and fuel pump failure.1... 

The chain terminating additives are usually aromatic amines, phenols, or sulfides. Those that inhibit the catalytic effect of metallic ions such as Cu, Fe, Pb, Mn, and Co are generally organic sulfides, phosphites, or thiophosphates. Although oxidation or corrosion inhibitors are frequently referred to separately, many of the phosphorus and sulfur containing compounds are effective in both applications. The entire matter of oxidation is affected by many things, including the temperature of the lubricant and the material of construction of the equipment in which the lubricant is used. It is also materially affected by inherent resistance of the base oil to oxidation. 

Attack by organisms other than SRB. Ammonia and amines are produced by microbial decomposition of organic matter under both aerobic and anaerobic conditions (ammo-nification). (Stott)5 These compounds are oxidized to nitrite by aerobic bacteria such as Nitrosomonas or Nitrobacter species. Nitrobacter is very efficient at destroying the corrosion-inhibition properties, of nitrate-based corrosion inhibitors by oxidation, unless a biocidal agent is included in the formulation. The release of ammonia at the surfaces of heat-exchanger tubes has a detrimental effect. (Stott)5... 

Use Corrosion inhibitor in alcohol-base antifreezes and water-cooled reactors. Oxidizing agent for organic material, especially in the presence of light heat-transfer medium. 

Carbon dioxide removal in ammonia plants is usually accomplished by organic or inorganic solvents with suitable activators and corrosion inhibitors. In a few circumstances, C02 is removed by pressure swing adsorption (PSA) (see Chapter 3). The removed C02 is sometimes vented to the atmosphere, but in many instances it is recovered for the production of urea and dry ice. Urea is the primary use of carbon dioxide and, in case of a natural gas feed, all of the C02 is consumed by the urea plant. This practice is especially significant since C02 is a proven greenhouse gas. Typically, 1.3 tons of C02/ton of NH3 is produced in a natural gas-based ammonia plant. The C02 vented to the atmosphere usually contains water vapor, dissolved gases from the absorber (e.g., H2, N2, CH4, CO, Ar), traces of hydrocarbons, and traces of solvent. Water wash trays in the top of the stripper and double condensation of the overhead help to minimize the amount of entrained solvent. The solvent reclaimer contents are neutralized with caustic before disposal. Waste may be burned in an incinerator with an afterburner and a scrubber to control NOx emissions. 

Only calcium nitrite, introduced more than thirty years ago, has a long and proven track record as a corrosion inhibitor for reinforced concrete [1,4]. MFP and alkano-lamine-based organic inhibitor blends are increasingly used but unfortunately most of the commercial apphcations lack rigorous control of the inhibitor effect. One of the very few comparative field tests on chloride-contaminated concrete studied MFP and a proprietary alkanolamine inhibitor added in the side-walls of a tunnel (16). The inhibitors were applied by the producers. The measurements of macrocell currents and half-cell potential mapping revealed that both inhibitors were virtually ineffective at the chloride concentrations of 1-2 % by mass of cement present [16]. 

N-heterocychc compounds Hke azoles [35], benzylaminopurine, [36], Schiff base [37], pyrimidine derivatives [38], pyridine derivatives [39], pyrazole derivatives [40], bipyra-zole derivatives [41], benzimidazole [42,43], and 2,3-diphenylbenzoquinoxaline [44] have been successfiiUy used as acidic inhibitors for corrosion protection of steel in an acidic environment. Organic corrosion inhibitors decrease the corrosion rate by... 

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