To verify the Beer-Lambert Law 2. To determine the composition of complexes by using Job Method Introduction: Job method is also known as method of continuous variation. This method is used to determine the composition of a complex which is formed by two reacting species.
Claims What is claimed is: A method of substantially eliminating transition metal content in the continuous phase of a polyol polymer dispersion prepared by the in situ polymerization of one or more polymerizable monomers in a base polyol comprising in pan one or more double metal cyanide complex-catalyzed polyoxyalkylene polyether polyols, said base polyol containing transition metals derived from said double metal cyanide complex catalyst, said method comprising: The method of claim 1 wherein said continuous polyol phase contains less than 4 ppm of total transition metals calculated on the basis of a hypothetical transition metal atomic weight of The method of claim 1 wherein each transition metal contained in said continuous polyol phase is present in an amount less than or equal to 2 ppm based on the weight of said continuous polyol phase.
The method of claim 2 wherein said base polyol contains about 20 ppm or more of transition metals based on the weight of said base polyol. The method of claim 3 wherein said base polyol contains about 20 ppm or more of transition metals based on the weight of said base polyol.
The method of claim 1 wherein said encapsulative double metal cyanide complex catalyst is an encapsulative zinc hexacyanocobaltate complex catalyst. The method of claim 6 wherein said zinc hexacyanocobaltate complex catalyst contains complexing agents selected from the group consisting of t-butanol, and t-butanol together with a polyoxyalkylene polyether polyol having an equivalent weight of greater than Da.
The method of claim 1, wherein at least about 75 weight percent of the total transition metal content of said base polyol is associated with said dispersed phase. The method of claim 1 wherein said encapsulative double metal cyanide complex-catalyzed polyoxyalkylene polyether polyols are not treated to remove catalyst residues prior to in situ polymerization of polymerizable monomers.
The method of claim 1 wherein said encapsulative double metal cyanide-catalyzed polyoxyalkylene polyether polyol is filtered prior to in situ polymerization of polymerizable monomers, said filtered polyol yet containing greater than 2 ppm transition metal content based on the weight of said filtered polyol.
The method of claim 1 wherein a portion of transition metals are removed from said encapsulative double metal cyanide complex catalyzed polyoxyalkylene polyether polyol by allowing catalyst or catalyst residues to sediment from stored polyoxyalkylene polyether polyol and selecting as a portion of said base polyol a supernatant of said stored polyoxyalkylene polyether polyol.
The method of claim 1 further comprising a non-encapsulative double metal cyanide complex-catalyzed polyoxyalkylene polyether polyol, wherein said base polyol contains not more than 4 ppm total transition metals derived from said non-encapsulative double metal cyanide complex catalyst based on the weight of said base polyol.
The method of claim 1 wherein said encapsulative double metal cyanide complex catalyst is a substantially amorphous zinc hexacyanocobaltate complex catalyst exhibiting substantially no sharp peak in an X-ray diffraction pattern at a d-spacing of approximately 5.
The method of claim 1 wherein said polymerizable monomers comprise one or more vinyl monomers. The method of claim 14 wherein said one or more vinyl monomers comprise acrylonitrile, styrene, or mixtures thereof.
Description TECHNICAL FIELD The present invention pertains to a process for the manufacture of polymer polyols by the in situ polymerization of vinyl monomers and to the manufacture of polymer-modified polyols by the in situ polymerization of polyisocyanates and isocyanate reactive monomers, both types of in situ polymerization conducted in the presence of a polyoxyalkylene polyether base polyol.
More particularly, the present invention pertains to an improved process for manufacture of polymer polyols and polymer-modified polyols having substantially no catalyst residues in the continuous polyol phase wherein certain double metal cyanide complex-catalyzed polyoxyalkylene polyether polyols are used as the base polyol, and the in situ polymerization are conducted subsequently without removal of double metal cyanide complex catalyst residues.
Polyurethane foams prepared from such polyol polymer dispersions surprisingly require less catalyst concentration than similar foams prepared from dispersions employing conventional polyols as base polyols.
The majority of such polymer polyols and polymer-modified polyols are used in the polyurethane field for diverse applications, including cell openers and hardness enhancers for polyurethane foam, and as reinforcing additives for a variety of microcellular and non-cellular polyurethanes.
The manufacture of polymer polyols is by now well known, and may involve batch, semi-batch, and fully continuous processes. In all of these processes, one or more vinyl monomers such as acrylonitrile and styrene are polymerized in situ in one or more base polyols, with or without the presence of an added stabilizer.
The amount of monomer s fed to the reactor is selected to achieve the desired vinyl polymer solids content in the final polymer polyol product. The solids level may range from as little as 5 weight percent to upwards of 60 weight percent, however, it is most economical to produce polymer polyols at relatively high solids loadings even when a low solids product is desired.Experiments were performed on a bubbling system to study the effect of additives such as hydrochloric acid, sulfuric acid, phosphoric acid, citric acid and boric acid on wet flue gas desulfurization, using ethylenediamine as the absorbent.
This thematic group integrates expertise in probe chemistry and small animal MR imaging. A. Probe chemistry. Our chemistry is devoted to the design, synthesis and characterization of innovative probes based on metal, mainly lanthanide complexes for applications in magnetic resonance imaging.
The mean lifetime method has been used to determine the nucleation rate, calculate the Zeldovich nonequilibrium factor and the diffusion coefficient of nuclei, and determine the contribution of elastic stresses to the work of formation of a critical nucleus.
Depending on the Zn(II) salt and solvent used in the reaction, a third bridge can connect the Zn(II) and Ln(III) metal ions, giving rise to triple-bridged diphenoxoacetate in complexes , diphenoxonitrate in complex 5, and diphenoxo(9-anthracenecarboxylate) in complexes This half-reciprocal absorption titration method, which has been used successfully to determine the intrinsic leslutinsduphoenix.comb ofmolecules as hydrophobic as benzo[a]pyrene derivatives, (48) was found to provide a useful route to obtain intrinsic binding constants for the broad range of ruthenium complex of .
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