Inhibitors formulations

The derivatives used in corrosion inhibitor formulations for down-hole use constitute a significant industrial appHcation for polyamines. Again, mono- and bisarnidoamines, imidazolines, and polyamides made from the higher polyamines are the popular choices. The products made from DETA and fatty acids have been widely used (308). A wide variety of other polyamine-based, corrosion inhibiting derivatives have been developed, generally incorporating some form of oil-soluble or od-dispersible residue. Sulfur and its derivatives are also used in these polyamine-based corrosion inhibitors on... 

An understanding of the basic principles of the science of metallic corrosion is clearly vital for corrosion control, and as knowledge of the subject advances the application of scientific principle rather than an empirical approach may be used for such purposes as the selection of corrosion inhibitors, formulation of corrosion-resisting alloys, etc. 

Many inhibitors will lose their effectiveness in the presence of one or more of these effects. Indeed inhibitors may act as nutrient sources for some microbial organisms. In these circumstances it will be necessary to incorporate suitable baaericides in the inhibitor formulations. 

A difficulty arises in describing the precise chemical nature of many inhibitor formulations that are actually used in practice. With the advancing technology of inhibitor applications there are an increasing number of formulations that are marketed under trade names. The compositions of these are, for various reasons, frequently not disclosed. A similar problem arises in describing the composition of many inhibitor formulations used in the former Soviet Union. Here the practice is to use an abbreviated classification system and it is often difficult to trace the actual composition, although in many cases a judicious literature search will provide the required information. 

The following discussion is thus restricted to inhibitor formulations that can be described in chemical terms. 

Some corrosion inhibitors can encourage the production of fungal growths in the relatively static cold water in the header tanks of these systems. Biocides will then often need to be included in the inhibitor formulation. 

Elsewhere, in a series of Japanese patents, mixtures of resorcinol + sodium nitrate, glycerine + sodium nitrate, lithium hydroxide + tungstate, etc., have been claimed to be effective. An example of the use of inhibited cooling mixtures of low toxicity is provided by a patent which describes a mixture of silicate-I- polyphosphate -I- a saccharide, e.g. sucrose or fructose, as the inhibitor formulation in a propylene glycol -I- potassium-hydrogen-carbonate mixture used in aluminium cooler boxes for ice-cream. 

In practice, the process of periodically topping up the inhibitor formulation through a hose cock or via a timer-controlled pump works well when water losses are minimal and the boiler is clean. But as discussed previously, when excess water is lost from the system through various means and MU demands become significant, the practice becomes one of chasing your own tail, and the various common forms of waterside corrosion, sludging, and deposition rapidly develop and flourish. 

Here, the use of inhibitor formulations having a less dramatic effect on TDS (such as certain tannins) may be extremely beneficial. Formulations are available that are based on tannin chemistry and contain blends that act as oxygen scavengers and metal passivators, with additional sludge dispersant and antifoam properties. 

Because of the duty requirements of these systems, pipework layouts are often tortuous and may contain stagnant areas where localized corrosion may develop or sludge may accumulate. The breakdown of glycols may also contribute to the development of foulants and corrosion debris. It is therefore good practice to incorporate both general dispersants (say, a 4,000-5,000 MW polyacrylate) and iron dispersants (say, a terpolymer) in the inhibitor formulations. 

They are used only sparingly in anodic inhibitor formulations, but the chemistry remains important. However, phosphates are extensively employed in other boiler chemical products for such purposes as hard-... 

As a consequence, it is not possible to devise a single class of anodic inhibitor formulation that satisfies all water treatment requirements. Rather, there several types of formulations, and some formulators may offer each of these products in different strengths, with or without oxygen scavengers and indicator dyes in their blends. As examples, a nitrite/sUicate formulation and a molybdate/nitrite formulation are provided here ... 

Basic Formulation Materials Glycol Inhibitor Formulation... 

Other common poly glycol-based antifoams include certain derivatives of polyethylene glycol (PEG), which are condensation polymers of ethylene glycol. An example is polyethylene glycol-8 dioleate. Apart from its antifoam properties, PEG-8 dioleate is also used in cooling water inhibitor formulations as a surface cleaner, in the formation of a corrosion-inhibiting surface film. Additionally, it is employed as an oil-soluble emulsifier for other defoamer chemistries. 

A corrosion inhibitor with excellent film-forming and film-persistency characteristics is produced by first reacting Cig unsaturated fatty acids with maleic anhydride or fumaiic acid to produce the fatty acid Diels-Alder adduct or the fatty acid-ene reaction product [31]. This reaction product is further reacted in a condensation or hydrolyzation reaction with a polyalcohol to form an acid-anhydride ester corrosion inhibitor. The ester may be reacted with amines, metal hydroxides, metal oxides, ammonia, and combinations thereof to neutralize the ester. Surfactants may be added to tailor the inhibitor formulation to meet the specific needs of the user, that is, the corrosion inhibitor may be formulated to produce an oil-soluble, highly water-dispersible corrosion inhibitor or an oil-dispersible, water-soluble corrosion inhibitor. Suitable carrier solvents may be used as needed to disperse the corrosion inhibitor formulation. 

Use amprenavir oral solution only when amprenavir capsules or other protease inhibitor formulations are not therapeutic options. 

Pharmacology Brinzolamide and dorzolamide are carbonic anhydrase inhibitors formulated for topical ophthalmic use. 

Methode d obtencion d e thyl-cellulose) 8) R.F. Warren, Edit, "Ethyl Cellulose , ChemEngrg, March 1951, p 279 9) J.M, Caraher, "Development of an Ethyl-cellulose Inhibitor Formulation , NAVORD Rept 4977 NOTS 1304) (Sept 1957) 10) Cond-... 

Thus, to confirm the preceding, combinations of polyacrylates, phosphonates, and PMA-based products have been mainstays of chemical inhibitor formulations for the last 30 years or so. 

In addition, in Table 5.6 and Figure 5.9 some azoles are given, which commonly form part of the inhibitor formulation as corrosion inhibitors for nonferrous metals. 

Inhibitor formulations, for example, can be modified to cater to makeup waters with zero, low, medium, or high levels of hardness or alkalinity. 

Today, almost all inhibitors sold are liquid products and contain some water. It is generally not possible to obtain any formulation that does not contain at least 50 to 70% water, if only because almost all the starting-point raw materials (whether commodity or specialty ingredients) are supplied in aqueous solution. Typically these materials are extremely viscous liquids that contain approximately 50% water and 50% actives. Blending and stabilizing these raw materials and ensuring that they are readily pumpable normally requires the addition of some extra dilution water into the inhibitor formulation. 

Thus, most inhibitor formulations have tended to utilize some inorganic component, such as Zn, Mo, or PO4, not only for duty as an active ingredient, but also to provide a suitable means of analyzing the inhibitor reserve in the cooling system. 

As part of this practical survey and cooling water program guide, selection notes on various inhibitor formulations follow. They are presented in Tables 8.3 to 8.10. 

Manufacturers of specialty chemical inhibitor formulation ingredients (the polymer manufacturers mainly) are still not able to confirm, with any degree of certainty, the minimum amount of product necessary to achieve any particular level of inhibition performance under various real-time, cooling system operating conditions. (The levels of active inhibitors proposed in most manufacturers technical literature tend therefore to be high, and when linked to the prices charged may make for uncompetitively priced formulations.)... 

Modem chemical inhibitor formulations are capable of effectively dealing with many of the problems that can be encountered during the operation... 

Detergent inhibitor formulation, or direct injection (normally diesel), or drive ability index. 

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