Filmer

Isobutyraldehyde also undergoes consecutive aldol and Tischenko condensations to give 2,2,4-trimethyl-l,3-pentanediolmonoisobutyrate [25265-77-4] (Texanol, Filmer IBT), alternatively prepared by the esterification of TMPD with isobutyric acid. 

The monoisobutyrate ester of TMPD, Texanol, or Filmer IBT, formally an isobutyraldehyde trimer, is prepared in a single step from isobutyraldehyde or, alternatively, by the esterification of TMPD with isobutyric acid. This monoester is most commonly employed as a coalescing agent for latex-based paints and water-based ink formulations. 

Appropriate chemical treatment of water (with corrosion inhibitors, dispersants, and filmers)... 

Chemical corrosion inhibition can reduce all forms of corrosion including dealloying. In particular, filmers such as tolyltriazole are effective in reducing corrosion of yellow metals. 

An Alternative Allosteric Model The Sequential Allosteric Model of Koshland, Nemethy, and Filmer... 

Koshland, D. E., Jr., Nemethy, G., and Filmer, D., 1966. Compari.son of experimental binding data and dieoretical models in proteins containing snbnnits. Biochemistry 5 365-385. The KNF model. 

Under these conditions, because the neutralizing amine has no effect on oxygen ingress, it is common to supplement the neutralizing amine blend with a filming amine. Thefilmer may be applied separately (usually to a steam header) or blended with the neutralizers and added to the FW, or sometimes directly to the boiler. Care should be exercised when filmers are employed in previously corroded systems because it is very likely that old corrosion debris will be transported away to cause severe blockages in steam traps and valves. 

Where both oxygen and carbon dioxide are a problem, an alternative to the neutralizer-filmer blend is the use of a neutralizer-YOS blend. 

Under particularly difficult conditions, neutralizing amines are expensive and not always totally successful. The use of satellite dosing points and programs that combine neutralizers with filmers (either fed separately or as a combination product) may produce the desired result. Proof of effectiveness requires pH and Fe/Cu/Ni mass balance profile trials to be undertaken. 

Additionally, the surfactant properties of filmers reduce the potential for stagnant, heat-transfer-resisting films, which typically develop in a filmwise condensation process, by promoting the formation of condensate drops (dropwise condensation process) that reach critical mass and fall away to leave a bare metal surface (see Figure 11.2). This function, together with the well-known scouring effect on unwanted deposits keeps internal surfaces clean and thus improves heat-transfer efficiencies (often by 5-10%). 

Filmers are based on primary, secondary, or tertiary monoamines or diamines and contain alkyl chains with from 8 to 22 carbons. The most prominent material is the 18-carbon-chain aliphatic monoalkylamine, octadecylamine (ODA). 

Protection is provided generally within the pH range of 4 to 8.5 or 9.0, although condensate more usually ranges from a low of pH 5.5 (untreated) to a high of 8.5 (when treated by neutralizing amines). Filmers are stable to 1,200 psig (538 °C). 

For the most part, the corrosion protection potential of filmers improves with increased packing of amines onto the metal surface, so straight-chain-only amines are preferred (no side chains or branched-chain amines) for formulation purposes. 

A typical feed rate is 1 to 3 ppm of active amine. Most filmer products contain between 3 and 10% amine (3-5% being the norm), so that product feed rates are around 10 to 30 ppm, dosed continuously to achieve 0.1 to 0.5 ppm amine (as ODA) in the returned condensate. However, products generally are diluted to 2 to 20% strength before application. Solutions are best prepared by using warm to hot condensate (150-160 °F/66-71 °C maximum) and agitated with a mechanical mixer until a uniform solution is reached. The solution should always be kept over 60 °F/16 °C. 

Once a filmer program starts, feeding of amine must be continuous because with the gradual removal of old iron oxide debris, the clean metal surface is subject to rapid corrosion should the continuous film cease to be maintained. 

Testing is undertaken by several methods, including chloroform extraction and use of a sulfonphthalein dye (absorbance of yellow-colored complex using bromophenol blue and bromocresol green) or the use of eosin (sodium tetrabromofluorescein) solution in acetone and tetrachloroethane solvent. After shaking with a citric acid buffer and eosin addition, upon standing the lower layer turns pink if filmer is present. Subsequent titration with Manoxol OT (sodium dioctyl sulfosuccinate) quantifies the filmer, with loss of the pink color indicating the end point. 

As with neutralizing amine formulations, there is a wide range of filmer raw materials employed. These are available in a myriad of straight filmer or filmer-neutralizer blends, of varying active strengths. A few examples are shown here ... 

Simple Filmer Formulation (a) Materials Octadecylamine 10% emulsion 100.0%... 

Complex Filmer-Neutralizer-Volatile Scavenger Formulation Materials... 

D. E. Koshland, G. Nemethy, and D. Filmer, Comparison of experimental binding data and theoretical models in proteins containing subunits. Biochemistry 5(1), 365 368 (1966). 

The second extreme case, suggested by Koshland, Nemethy, and Filmer (KNF) (Koshland et al., 1966), is also known as the sequential model. The mathematical conditions required to obtain this limiting case are quite severe. First, it is assumed that, in the absence of a ligand, one of the conformations is dominant, say the LL form. In addition, it is assumed that a ligand binding to any subunit will change the conformation of that subunit into the H form. These assumptions lead to the consideration of only the four diagonal states of Fig. 4.18, for which the PF is... 

The MWC model is presently known as the concerted model, since the entire protein changes its conformation concertedly. The induced-fit model was later developed by Koshland, Nemethy, and Filmer (KNF) and is presently known as the... 

Note that the Adair equation does not provide a reason for why identical sites would have different dissociation (or association) constants. See Allosterism Cooperativ-ity, Koshland-Nemethy-Filmer Model... 

Linked-function mechanisms for cooperative binding interaction of metabolites and/or drugs, based on the presence of two or more different conformational states of the protein or receptor. See Adair Equation Cooperative Ligand Binding Hemoglobin Hill Equation Plot Koshland-Nemethy-Filmer Model Monod-Wyman-Changeux Model Negative Cooperativity Positive Cooperativity... 

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