Abstract: The present invention relates to a method for preparing a catalyst for glycerin dehydration, a catalyst for glycerin dehydration prepared thereby, and a method for preparing acrolein. More particularly, the catalyst for glycerin dehydration prepared by the preparation method is able to minimize by-product formation to improve acrolein selectivity and to maintain high catalytic activity during the reaction.

Abstract: A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, optionally a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers to total metal ions is greater than 0.2, and an oxidant at an initial temperature in the range of about 20° C. to about 95° C. Temperature conditions are provided effective to enable oxidation of cerous ion to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles, optionally containing one or more metal ions (M), Ce1-xMxO2-?, wherein “x” has a value from about 0.0 to about 0.95. The nanoparticles may have a mean hydrodynamic diameter from about 1 nm to about 50 nm, and a geometric diameter of less than about 45 nm.

Abstract: The present invention relates to crystalline cerium oxide prepared in a simple, economical, and efficient manner, of which crystal structure, shape, and size can be easily adjusted and that exhibits excellent polishing properties, and a preparation method thereof. The crystalline cerium oxide can be prepared as sub-micron crystalline cerium oxide that has a mean volume diameter and a diameter standard deviation within a predetermined range.

Abstract: A particulate subcomponent for a barium titanate dielectric is obtained from a sol in which a rare earth metal compound is dispersed in water. The rare earth metal compound includes a carboxylic acid having at least three carbonyl groups and at least one rare earth metal which can be Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu so that the molar ratio (carbonyl group/rare earth metal) is in the range of 1.2 to 3. A method of making the sol and a method of using the sol to make a ceramic powder is described.

Abstract: Formulations useful for preparing hydrous hafnium oxide gels contain a metal salt including hafnium, an acid, an organic base, and a complexing agent. Methods for preparing gels containing hydrous hafnium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including hafnium, an acid, an organic base, and a complexing agent.

Abstract: Formulations useful for preparing hydrous cerium oxide gels contain a metal salt including cerium, an organic base, and a complexing agent. Methods for preparing gels containing hydrous cerium oxide include heating a formulation to a temperature sufficient to induce gel formation, where the formulation contains a metal salt including cerium, an organic base, and a complexing agent.

Abstract: The present invention provides an approach to control the generation and grow of nanocrystal with membrane diffusion method and related apparatuses to produce inorganic oxide nanopowders and metal nanoparticles. With this method, the size and size distribution of inorganic oxide nanopowders and metal nanoparticles can be tuned. It overcomes the shortcomings possessed by the common chemical and physical method of preparing nanoparticles.

Abstract: The present invention relates to a method of preparing a cerium oxide powder for a CMP slurry and a method of preparing a CMP slurry using the same, and more particularly, to a method of preparing a cerium oxide powder for a CMP slurry and a method of preparing a CMP slurry using the same in which the specific surface area of the powder is increased by preparing a cerium precursor, and then decomposing and calcinating the prepared cerium precursor. The pore distribution is controlled to increase the chemical contact area between a polished film and a polishing material, thereby reducing polishing time while the physical strength of powder is decreased, which remarkably reduces scratches on a polished film.

Abstract: There is provided a production method of an yttrium oxide-stabilized zirconium oxide aqueous sol and organic solvent sol capable of producing a sol having extremely advantageous transparency with which the heating condition is eased compared to that of a conventional method and secondary aggregation of the obtained colloidal particle is hardly caused. A production method of an yttrium oxide-stabilized zirconium oxide aqueous sol, characterized by comprising: a process of subjecting a mixed aqueous solution produced by dissolving an yttrium carboxylate and zirconium oxyacetate in water in an Y/(Y+Zr) atomic ratio in a range of 0.10 to 0.60 to hydrothermal treatment at 160 to 280° C. for 2 hours or more.

Abstract: The invention concerns a colloidal dispersion of a vanadate or a phosphovanadate of at least a rare earth comprising either a complex-forming agent having a pK higher than 2.5, or an anion of a monovalent acid, soluble in water and having a pKa ranging between 2.5 and 5. The dispersion is obtained by contacting a colloidal dispersion or a dispersion of initial complexes comprising at least a rare earth compound and at least a complex-forming agent or an anion of said monovalent acid and whereof the pH has been adjusted to a value of at least 7, with vanadate ions, then, in adjusting the pH of the resulting medium to a value of at least 9 and heating.

Abstract: An improved gas diffusion electrode composed of a perovskite-type oxide dispersed in a mixture of carbon black and a hydrophobic binder polymer. An improved catalyst for use in the electrochemical reduction of oxygen comprising a perovskite-type compound having alpha and beta sites, and having a greater molar ratio of cations at the beta site. A particularly good reduction catalyst is a neodymium calcium manganite. An improved method of dispersing the catalysts with carbon in a reaction layer of the electrode improves performance of the electrode and the oxygen reduction process. This is provided by adding carbon black to an aqueous solution of metal salts before it is heated to a gel and then to a char and then calcined. Optionally, a quantity of the desired oxide catalyst can be premixed with a portion the carbon before adding the carbon to an aqueous solution of the metal salts to be heated.

Abstract: The invention concerns a colloidal dispersion of a phosphate of a rare earth and a process for its preparation. The dispersion is characterized in that it comprises anisotropic and disaggregated or disaggregatable particles of a phosphate of at least one rare earth and an anion of a monobasic acid, soluble in water and with a pKa of at least 2.5. It is prepared by a process in which a solution of a salt of at least one rare earth is mixed with phosphate ions while controlling the pH of the reaction medium to a value in the range 4 to 9 and in the presence of a monobasic acid, soluble in water and with a pKa of at least 2.5; the mixture obtained optionally undergoes a maturing step; the precipitate is then separated from the reaction medium; and said precipitate is then dispersed in water.

Abstract: The invention concerns an aqueous colloidal dispersion of isotropic particles of a phosphate of at least one rare earth and is characterized in that it comprises either a complexing agent with a pK (cologarithm of the dissociation constant of the complex formed by the complexing agent and said rare earth) of more than 2.5; or an anion of a monobasic acid, soluble in water and with a pKa in the range 2.5 to 5; or said complexing agent and/or said anion of a monobasic acid. In the case of cerium and lanthanum, the mean particle size is at most 20 nm. The dispersions can have a degree of colloid agglomeration of less than 40%.This dispersion can be prepared by forming an aqueous mixture comprising at least one rare earth salt and the complexing agent or monobasic acid anion; by adding a base then phosphate ions to the mixture formed; and heating the mixture obtained. A precipitate is obtained that is re-dispersed in water.

Abstract: An aqueous colloidal dispersion of at least one lanthanide compound and a complexing agent with a pK (cologarithm of the dissociation constant of the complex formed by the complexing agent and the lanthanide cation) or more than 2.5. The dispersion can also include a compound of at least one other element selected from groups IVa, Va, VIIa, VIIa, VIII, Ib and IIb of the periodic table. A process for preparing the dispersion starts by forming an aqueous mixture comprising at least one lanthanide salt, optionally a salt of one of the elements mentioned, and the complexing agent. A base is added to the mixture, which is heated to obtain the dispersion. Methods that use the dispersion are also disclosed.

Abstract: A dispersion of pyrogenically produced cerium oxide, which does not contain any particles larger than 1 ?m, is produced by dispersing a pyrogenically produced cerium oxide in water by means of a dissolver, centrifuging it, separating the supernatant from the bottom product, and again dispersing the supernatant by means of ultrasound. The dispersion can be used for chemical-mechanical polishing (CMP).

Abstract: The invention concerns a colloidal dispersion of a phosphate of a rare earth and a process for its preparation. The dispersion is characterized in that it comprises anisotropic and disaggregated or disaggregatable particles of a phosphate of at least one rare earth and an anion of a monobasic acid, soluble in water and with a pKa of at least 2.5. It is prepared by a process in which a solution of a salt of at least one rare earth is mixed with phosphate ions while controlling the pH of the reaction medium to a value in the range 4 to 9 and in the presence of a monobasic acid, soluble in water and with a pKa of at least 2.5; the mixture obtained optionally undergoes a maturing step; the precipitate is then separated from the reaction medium; and said precipitate is then dispersed in water.

Abstract: A cerium and/or lanthanum phosphate sol includes an aqueous phase; particles of a phosphate of at least one rare earth selected from cerium and lanthanum; and an acid other than phosphoric acid, the cerium and lanthanum salts of which are soluble in water. A process for preparing this sol includes continuously introducing a first solution of salts of at least one of the rare earths into a second solution of phosphate ions with an initial pH of less than 2; controlling the pH of the precipitation medium during precipitation at a constant value of less than 2; separating the precipitate from the reaction medium and of taking up the dispersion in water then adding to the dispersion obtained at least one said rare earth salt and said acid in a quantity such that the final PO43/rare earth mole ratio in the dispersion is 1.

Abstract: A subject matter of the invention is a process for the preparation of particles comprising at least one metal ion, which comprises the stage of bringing into contact a precursor a metal cation, optionally partially hydrolyzed, with at least one water-soluble comb copolymer. Likewise, a subject matter of the invention is particles capable of being prepared according to the process of the invention, said particles exhibiting a mean size of between 2 and 500 nm and preferably between 2 and 300 nm. Finally, it relates to the use of such particles in the mechanical polishing of hard objects, in the preparation of pigments or mixed ceramics for the electronic industry, in the reinforcing of polymeric matrices, in fungicidal or biocidal dispersions, in the scavenging of sulfur derivatives or the scavenging of unpleasant smells.

Abstract: A process is provided for preparing solid superconducting mixed-metal oxides whereby the superconductor can be formed into any predetermined shape by way of viscous sol precursors. The superconductors are also formed by this process into homogeneous phases.

Abstract: The present invention provides for the use of bis(perfluoroalkanesulfonyl)imide and its salts as surfactants or additives applications having an extreme environment.

Abstract: A surface treatment, especially for titanium and aluminum alloys, forms a Si—Y sol-gel film covalently bonded on the metal surface to produce strong, durable adhesive bonds between the metal and an organic adhesive without using toxic chemicals and while significantly reducing or eliminating rinse water requirements of traditional anodizing or etching processes. The sol should produce bonds in a single application comparable in strength and performance to standard anodize controls. Parameters affecting performance include the sol composition, the ratio of silicon to yttrium in the sol, the ratio of other sol ingredients, the concentration of the sol, the carrier solvent, solution age, catalysts, surface pretreatment, application method, curing process, and primer used.

Abstract: Process for preparing mineral particles in the form of colloids in aqueous dispersion of controlled size from a precursor, comprising: a) the step of putting the said precursor, which is a mineral salt of a metal cation, into aqueous solution; b) the complexation of the product obtained in a) with at least one water-soluble block copolymer having at least one complexing anionic hydrophilic block and at least one stabilizing nonionic hydrophilic block; and c) the partial or complete hydrolysis of the said precursor in order to obtain controlled growth of the mineral particles in the form of an aqueous dispersion. Use of said colloids, especially as reinforcing fillers for a polymer.

Abstract: Disclosed is a zinc-oxide containing sol comprising a core of cerium dioxide sol the surface of which particles is coated with zinc oxide; and the method of making the sol. The sol has a mean particle size of less than 50 nm, is characterized as being clear and transparent and is stabilized to resist agglomeration and particle size increase. An essential part of the disclosed invention is the addition of a positive charged oxide such as yttrium oxide to effect the stabilization before significant changes in transparency, agglomeration and/or particle size increase can occur.

Abstract: A method for regenerating a fluorescent material from a recovered phosphor slurry characterized by including a chemical washing step wherein a hypochlorite and a periodate are used; a carbon removing step for floating carbon in the supernatant liquid by the use of ammonia thereby removing the carbon; an acid washing step; and a heat treating step in this order as well as a system for regenerating a fluorescent material comprising means for effecting the aforesaid steps. From this constitution, it becomes possible that impurities are easily and effectively removed from the recovered phosphor slurry, whereby a fluorescent material providing excellent luminance and excellent grade of phosphor film can be regenerated.

Abstract: The present invention provides production methods for aqueous dispersion slurry of inorganic particles which are so stable as not to increase in viscosity, gel or sediment even if stored for a long time and whose average particle diameter is 0.01 to 2 .mu.m. As such production method, 2 production methods are available:A production method (A) having a preliminary dispersion process in which the inorganic particles are added to ad dispersed in an aqueous medium and a main dispersion process in which dispersed slurry out of the preliminary dispersion process are collided with each other under a pressure of 100 to 3,000 kg/cm.sup.2 ; andA production method (B) in which the inorganic particles are added to an aqueous medium within a kneading tank of a kneader in which mixing blades rotate around respective subsidiary spindles and the subsidiary spindles revolves around a spindle and dispersed at a solid concentration of 30 to 70 wt %.

Abstract: In a first embodiment of the invention, a colloidal dispersion of a cerium compound is characterised in that it has a pH of at least 4 and a conductivity of at most 5 mS/cm. In a second embodiment, the colloidal dispersion is characterised in that it has a pH of more than 5. In a third embodiment, the colloidal dispersion is characterised in that the colloids have a carbon content such that the carbon/cerium mole ratio is at Least 0.01 and in that the pH is greater than 5.A process for the preparation of these dispersions is characterised in that a first colloidal dispersion is used as a starting material, with a pH which is lower than the pH of the dispersion which is to be prepared, and the pH of the first dispersion is raised while reducing the ionic strength. For the third embodiment, an organic acid is added to the starting dispersion.