TECHNOLOGY FOCUS - CHEMICAL ENGINEERING - Preferred Method: The formation of product takes place by a process involving a sol-gel reaction. The introduction of materials into the reactor is done in arbitrary order. The solid reactor filling material, metal-containing precursor, co-solvent and/or supercritical solvent are mixed before introducing in the reactor. The product is obtained in batch mode, quasi-batch mode or continuous mode. The product is separated from the solid reactor filling material by flushing the material in fluid, vacuum unit, blowing unit or ultrasonic unit.Preferred Product: The metal oxide, metal oxyhydroxide or metal hydroxide product is crystalline or amorphous, or a mixture of several different phases.Preferred Condition: The temperature in the reactor is kept fixed during product formation or is increased or decreased. The reactor temperature during product formation may be an arbitrary combination of two or more temperature profiles of fixed temperature, decreasing temperature and increasing temperature. The maximum temperature of the reactor is 400 degrees C, preferably 50 degrees C. The pressure in the reactor during product formation is kept at fixed pressure, increased or decreased. The pressure profile may be an arbitrary combination of two or more pressure profiles of fixed pressure, increasing pressure and decreasing pressure. When the supercritical solvent is carbon dioxide, the minimum pressure in the reactor is 74 bar, preferably 100 bar and the minimum temperature in the reactor is 31 degrees C, preferably 400 degrees C. When the supercritical solvent is isopropanol, the minimum pressure in the reactor is 47 bar, preferably 100 bar and the minimum temperature in the reactor is 235 degrees C, preferably 400 degrees C. The supercritical solvent is supercritical before introducing in the reactor, or made supercritical after introducing into the reactor. The maximum time required for formation of product is 24 hours, preferably 0.5 hours. Several types of metal-containing precursor are introduced into the reactor.Preferred Material: The solid reactor filling material functions as heterogeneous catalyst, and comprises promoter(s), fiber(s) and powder. The material has shape of sponge, grid, wad of fibers or sheet and has porous structure. The solid reactor filling material has size and shape capable of confining the metal-containing precursor to limited portion of the reactor. The material contains a polymer, metal, metal oxide, ceramic, metal sulfate, metal halide, metal oxyhydroxide or metal hydroxide identical to the product. The material functions as seed material for product formation and as collecting agent. The product is separable from the solid reactor filling material without requiring further treatments of the material. Degradation of the material is prevented and it is reused again as solid reactor filling material.Preferred Metal: The metal is titanium, aluminum, zinc, vanadium, magnesium, zirconium, chromium, molybdenum, niobium, tungsten, copper or iron. The metal oxide is oxide of these metals.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Precursor: The metal-containing precursor is metal alkoxide such as titanium tetraisopropoxide, titanium butoxide, titanium ethoxide, titanium methoxide, aluminum isopropoxide, aluminum-sec-butoxide or magnesium ethoxide, or metal salt such as Ti(SO4)2, TiCl4 or AlCl3.Preferred Solvent: The co-solvent is water, ethanol, methanol, hydrogen peroxide or isopropanol. Several types of co-solvents may be introduced in the reactor.    TECHNOLOGY FOCUS - POLYMERS - Preferred Material: The polymer present in the solid reactor filling material is polystyrene, polypropylene, polyethylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, acrylic polymer, fluorinated polymer, diene polymer, vinyl copolymer, polyamide polymer, polyester polymer, polyether polymer or polyimide polymer.