Foam catalysts

Diorganotin dichlorides, in diorganotin preparation, 24 820 Diorganotin dihalides, 24 820 Diorganotin esters, 24 820 Diorganotin mercaptocarboxylates, as polyurethane foam catalysts,... 

Finally, catalysts are very useful in controlling air flow. By controlling the sizes of cells or by causing the windows between cells to burst (to produce an open-cell foam), catalysts represent important tools in the effort to control air flow-through. 

This section deals with additives used to initiate and accelerate reactions of isocyanates and epoxides. Polyurethanes are very versatile materials, capable of being formulated into a wide variety of products (B-64MI11501, B-78MI11504, B-71MI11500). Many important applications involve the production of foams catalysts play a key role in balancing the rates of the various reactions involved. 

Urea, 3-oxo-A4-1,2,4-thiadiazolin-5-yl-synthesis, 6, 592 Urea, thio-cyclic derivatives toxicity, 1, 138-139 toxicity, 1, 139 Urethane foam catalysts, 1, 405-406 Urethanes... 

As indicated above, the new applications of organolead have been fostered largely through the interest of ILZRO. The most promising new applications are in the fields of marine antifouling paints, marine borer repellants for wood, antiwear additives for lubricants, polyurethan foam catalysts, and molluscicides for bilharzia control in tropical areas. 

Twigg MV, Richardson JT. Fundamentals and applications of structured ceramic foam catalysts. Industrial Engineering Chemistry Research. 2007 46(12) 4166-4177. 

Phenolic Foams. Cured phenolic resins have good thermal stability and high tendency to char in an intensive fire. Even after the removal of the ignition source the foams often smolder and char until they are almost completely consumed. This phenomenon, called punking, is claimed to be overcome by the addition of boric acid/oxalic acid and ferric/aluminum chloride as the foaming catalysts. The addition of antimony compounds is also reported to decrease punking (38). 

Staff Written, "Additives and Modifiers - Urethane Foam Catalysts, Plastics Compounding 1991192 Redbook, 14(4) 56-58 (July/August 1991). 

Foaming agents Polyurethane foam catalysts Foam processing... 

Ethylamine is primarily used in the production of triazine herbicides. Ethylamine has also found use in resin chemistry, oil refining, and solvent extraction as a stabilizer for latex rubber and in the manufacture of dyestuffs, medicinals, corrosion inhibitors, urethane foam catalysts, and agents used in wash-and-wear fabrics. 

Horn, R., Williams, K.A., Degenstein, N.J., Bitsch-Larsen, A., Dalle Nogare, D., Tupy, S.A., and Schmidt, L.D. Methane catalytic partial oxidation on autothermal Rh and Pt foam catalysts Oxidation and reforming zones, transport effects, and approach to thermodynamic equilibrium. Journal of Catalysis, 2007, 249 (2), 380. 

However, when a 2/1 mixture of C2H6 and O2 are passed over a Pt containing ceramic foam catalyst at velocities between 0.1 and 1 m/sec, the primary carbon containing product is ethylene, and no detectable carbon buildup is detect on the catalyst even after many... 

Nevertheless, the use of a supported noble metal catalyst (usually Pt) for soot oxidation under loose contact conditions (proposed to be closer to the practical condition) results in a significant decrease in the soot oxidation temperature.76,94,97,98 Thus, incorporation of the soot in a Pt/SiC foam catalyst allows the soot oxidation rate to be doubled (and also to decrease the maximum rate temperature) with respect to a non-catalysed situation in which the soot is incorporated into the Pt-free SiC foam (with Pt/SiC foam located upstream to promote NO oxidation). In turn, a considerable decrease in the maximum rate temperature is observed when employing NO + O2 instead of O2 as oxidant in the Pt/SiC-soot configuration.98 On the basis mainly of these results, a catalytic role for NO is proposed in a recycle reaction as follows ... 

J.T. Richardson, Y. Peng, D. Remue, Properties of ceramic foam catalyst supports pressure drop, Appl. Catal. A Gen. 204 (2000) 19. 

In conventional processes (Stamicarbon and Inventa), hydroxylamine sulfate is prepared by the Raschig technique. The first reaction is the catalytic combustion of ammonia in air at 850°C. in the presence of a platinum foam catalyst The heat generated by the reaction is recovered in a boiler which produces steam. Nitrogen oxides are formed by the following reaction mechanism ... 

The freshly prepared, flexible PU foams, using tertiary amines as foaming catalysts, are well known to have an unpleasant odour, characteristic of amines. The staining of vinylic films or degradation of polycarbonate sheets is produced as a consequence of the aminic catalyst emission from PU foams. This problem is serious, especially in environments where there are elevated temperatures for long periods of time, for example in an automobile interior. These problems need a reduction of migratory amine catalyst emissions. 

Table 4 compares these results with predicted performance for a foam catalyst, using the same kinetics but inserting heat transport correlations for the foam. An increase in Ag loading to 12.5% gave the same conversion, as predicted by Table 3, but selectivity remained the same. The most dramatic change was the decrease in the difference between the temperature at the center... 

S. A. Brown, The kinetics of exothermic reactions on ceramic foam catalysts, Ph.D. Dissertation, University of Houston, September 2001. 

The most active foam catalysts were tested in the process of neutralization of gas emissions of furnaces for wire enameling. Waste gases contained mixture of vapors of different (mainly aromatic) organic compounds in amount of 10-50 g/m. Temperature of the waste gases was 380-450°C. The existing catalytic neutralization system (2 % Pd on Nichrome wire) did not give the necessary degree of purification (72-80 % conversion only). 

The initial material for the foam catalyst may be any metal or alloy capable of existing, under normal conditions, in the metallic state (Cu, Ag, Ni, W, steel, Nichrome, etc.), or ceramics of various composition. Corrosion-resisting Nichrome and stainless steel are preferable materials of the foam support for deep oxidation processes. Foam ceramics is the most stable to corrosion however, it is brittle and can be broken under hard operating conditions. 

Foam catalysts with intermediate layer Y-AI2O3 exhibit the best catalytic activity in deep oxidation reactions. 

Precaution Combustible liq. corrosive to copper, brass, and aluminum Hazardous Decomp. Prods. Thermal decomp, prods. CD, CO NO, Uses Solubilizer for resins in aq. coatings fatty acid soaps as emulsifier for waxes, floor polishes, min. oil emulsions, insecticides mfg. of nonionic emulsions vapor-phase corrosion inhibitor PU foam catalyst ... 

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