Water-soluble inhibitor

The effect of various types of inhibitors with respect to structure and solubility on the formation of N-Nitrosodiethanolamine was studied in a prototype oil in water anionic emulsion, Nitrosation resulted from the action of nitrite on diethanolamine at pH 5.2-5.A, Among the water soluble inhibitors incorporated into the aqueous phase, sodium bisulfite and ascorbic acid were effective. Potassium sorbate was much less so. The oil soluble inhibitors were incorporated into the oil phase of the emulsion. 

In experiments with water-soluble inhibitors, the subsample was stirred under nitrogen during post-addition of an aqueous solution of the inhibitor followed by an aqueous sodium nitrite solution. Aliquots were weighed into 1-oz ointment jars, covered with nitrogen, sealed, and stored at 37 for later replicate analyses. Preparation of the positive control subsample was identical except that water was added in place of inhibitor. 

Inhibitors may be classified according to their solution properties as either oil-soluble inhibitors, water-soluble inhibitors, or dispersible inhibitors. Chemical inhibitors act as film formers to protect the surface of the pipeline. Corrosion inhibitors, used for the protection of oil pipelines, are often complex mixtures. The majority of inhibitors used in oil production systems are nitrogenous and have been classified into the broad groupings given in Table 11-4. Typical corrosion inhibitors are shown in Table 11-5. For details, see also Chapter 6. 

Ettmayer, P. Billich, A. Hecht, P. Rosen-wirth, B. Gstach, H. Paracyclophanes a 357 novel dass of water-soluble inhibitors of HIV proteinase./. Med. Chem. 1996, 39, 3291—3299. 

Barton et al. [232] conducted the emulsion polymerization of the sparingly water-soluble monomer St and of the fairly water-soluble monomer MMA in the presence and absence of the water-soluble inhibitor, potassium nitrosodi-sulfonate (Fremy s salt). By using oil-soluble dibenzoyl peroxide (DBP) and water-soluble ammonium peroxodisulfate (APS) as the free-radical initiators, they examined the effect of the location of the initiator on the kinetics of these emulsion polymerizations with SDS as the emulsifier. Figure 7 shows an example of the experimental results. 

Since emulsion polymerization is initiated in the aqueous phase, the undesirable formation of latex polymer can be minimized in suspension systems by using water-soluble inhibitors, like sodium nitrite. 

Several routes exist for the synthesis of amides of halo acids. Cuatrecasas et al. (1969) used two different bromoacetylating reagents in the synthesis of water soluble inhibitors of staphylococcal nuclease. The N-hydroxysuccinimide ester of bromoacetate was one of the reagents used. It is particularly useful for the synthesis of radioactive derivatives since C-bromoacetic acid is commercially available. Synthesis of the hydroxysuccininimide ester is accomplished by dissolving 87 mg (630 /imoles) of bromoacetic acid and 86 mg of N-hydroxysuccinimide in 3 ml of dioxane. To this solution, 132 mg (700 /imoles) of dicyclohexylcarbodiimide is added. Urea precipitates immediately and after 1 hr, is removed. The solution of bromoacetyl N-hydroxysuccinimide ester is brought to 5 ml. It can then be used without any further purification. 

However, in today s harsh oil/gas production environments where facilities and equipment are becoming old, with attendant increases in maintenance costs, the use of inhibitors as opposed to the use of other expensive corrosion mitigation methods becomes an obvious choice as cost-saving solutions to extend the life of assets and infrastructures. Researchers have now focused on the use of volatile inhibitors mixed with oil and water-soluble inhibitors for use in mitigating corrosion in multiphase systems such as in the control of internal corrosion of pipelines and corrosion of... 

Thiemermann C. Development of novel, water-soluble inhibitors of poly (adenosine 5 -diphosphate ribose) synthetase activity for use in shock and ischemia-reperfusion injury. Crit Care Med 2002 30 11.63-1165. 

Experiments of McPherson and Muller (1969), McPherson et al. (1971), and Muller and Chou (1972) have shown that substances responsible for the observed allelopathic effects are water soluble and waterborne with both species. One of the major climatic features of this vegetation is coastal fog even in the summer months and although rainfall is only moderate, there is a constant drip of moisture on to the leaves of these shrubs and, hence, onto the surrounding soil. This dripping is sufficient to carry a regular supply of water-soluble inhibitors from leaves to the soil where they remain in sufficient concentration to prevent growth or seed germination of any annual species near these shrubs (McPherson and Muller, 1969). 

N,N-dimethylaminoethyl methacrylate) (DMAEMA) by an SPG emulsification technique [34]. The process consists of two steps - emulsification and polymerization. The oil phase containing monomers (styrene and DMAEMA), hexadecane (HD) and an initiator N.hf-azobis (2,4-dimethyl valeronitrile) (ADVN) is pressed by nitrogen gas through the SPG membrane into the aqueous phase. The aqueous phase contains stabilizer polyvinyl alcohol (PVA), surfactant sodium lauryl sulfate (SLS), electrolyte Na2S04 and water-soluble inhibitor (NaN02 or diaminopheny-lene). The emulsion obtained is then transferred to a separate reaction kettle and polymerization is started by raising the reaction temperature to 70 °G. After 24 h, microcapsules with uniform size are obtained. 

Higher conversions are obtained when NaN02 is employed as a water-soluble inhibitor in the presence of DMAEMA. In the absence of DMAEMA no inhibitor is required. In all of these experiments, with both lower and higher amounts of HD, complete encapsulation was observed irrespective of the addition of DMAEMA (2.5 wt.%, 0%)... 

NACE A is a water-soluble inhibitor and is composed as follows ... 

Corrosion Inhibitors. A water-soluble corrosion inhibitor reduces galvanic action by making the metal passive or by providing an insulating film on the anode, the cathode, or both. A very small amount of chromate, polyphosphate, or silicate added to water creates a water-soluble inhibitor. A slightly soluble inhibitor incorporated into the prime coat of paint may also have a considerable protective influence. Inhibitive pigments in paint primers are successful inhibitors except when they dissolve sufficiently to leave holes in the paint film. Most paint primers contain a partially soluble inhibitive pigment such as zinc chromate, which reacts with the steel... 

Filming inhibitors are available in a wide variety of formulations and solubility characteristics. The question of whether to use an oil-soluble or a water-soluble inhibitor is somewhat arbitrary. Some operators prefer to use a water-soluble or water-dispersible inhibitor when the water to oil ratio of the producing well is greater than one. Other operators hold an opposing view, preferring to build a high concentration of oil-soluble inhibitor in the lesser phase. In practice, both methods have been... 

Inhibitor residuals are occasionally used to monitor corrosion control programs. By knowing at what concentration certain water soluble inhibitors give protection, we can generally tell if protection is being accomphshed. 

Enzymologists frequently study how reaction rates, substrate binding etc. vary under a variety of experimental conditions. Parameters which may be changed include pH, ionic concentration and the addition of water-soluble inhibitors. Thus, the membrane protein is only probed in regions where it is exposed to bulk water or at the interfacial region where such water meets the bilayer. This often only represents a small part of the whole membrane protein. 

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