Hydrothermal process for making ultafine metal oxide powders

• US 5,776,239 A
• Filed: 08/22/1997
• Issued: 07/07/1998
• Est. Priority Date: 10/27/1995
• Status: Expired due to Term

• Current Assignee: The Chemours Company FC, LLC (The Chemours Company)
• Original Assignee: E. I. du Pont de Nemours and Company (Corteva, Inc.)
• Inventors: Bruno, Salvatore Anthony
• Primary Examiner(s): Bell, Mark L.
• Assistant Examiner(s): Hertzog, Scott L.
• Application Number:
  US08/918,702
• Time in Patent Office: 319 Days
• Field of Search: 423/610, 423/611, 423/612, 423/616, 106/436, 106/437, 106/425, 106/426, 106/428, 106/430, 106/431, 106/453, 106/455
• US Class Current: 106/437
• CPC Class Codes: A61K 2800/58 Metal complex; Coordination compounds
• CPC Class Codes: A61K 8/19 containing inorganic ingredients
• CPC Class Codes: A61K 8/25 Silicon; Compounds thereof
• CPC Class Codes: A61K 8/26 Aluminium; Compounds thereof
• CPC Class Codes: A61K 8/27 Zinc; Compounds thereof
• CPC Class Codes: A61K 8/28 Zirconium; Compounds thereof
• CPC Class Codes: A61K 8/29 Titanium; Compounds thereof
• CPC Class Codes: A61K 8/58 containing atoms other than carbon, hydrogen, halogen, oxygen, nitrogen, sulfur or phosphorus
• CPC Class Codes: A61K 8/585 Organosilicon compounds
• CPC Class Codes: A61Q 17/04 Topical preparations for affording protection against sunlight or other radiation; Topical sun tanning preparations
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01B 13/366 by hydrothermal processing
• CPC Class Codes: C01G 19/02 Oxides
• CPC Class Codes: C01G 23/047 Titanium dioxide
• CPC Class Codes: C01G 23/053 Producing by wet processes, e.g. hydrolysing titanium salts
• CPC Class Codes: C01G 9/02 Oxides; Hydroxides
• CPC Class Codes: C01P 2002/60 Compounds characterised by their crystallite size
• CPC Class Codes: C01P 2002/72 by d-values or two theta-values, e.g. as X-ray diagram
• CPC Class Codes: C01P 2002/84 by UV- or VIS- data
• CPC Class Codes: C01P 2004/04 obtained by TEM, STEM, STM or AFM
• CPC Class Codes: C01P 2004/54 : Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
• CPC Class Codes: C01P 2004/62 : Submicrometer sized, i.e. from 0.1-1 micrometer
• CPC Class Codes: C01P 2004/64 : Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C01P 2006/12 : Surface area
• CPC Class Codes: C01P 2006/60 : Optical properties, e.g. expressed in CIELAB-values
• CPC Class Codes: C08K 3/22 : of metals
• CPC Class Codes: C09D 7/48 : Stabilisers against degradation by oxygen, light or heat
• CPC Class Codes: C09D 7/67 : Particle size smaller than 100 nm

Abstract

An ultrafine titanium dioxide powder is disclosed that can be produced by hydrothermal treating an amino titanium oxalate composition. Ultrafine titanium dioxide powders are useful in cosmetic and other applications for controlling exposure to ultraviolet (UV) light.

Claims

1. A process for making an inorganic powder comprising:

preparing an aqueous solution comprising oxalic acid,

adding a hydrolyzable metal compound to the aqueous solution of oxalic acid at a molar ratio of oxalic acid to metal compound of from about 0.9;

1 to about 1.1;

1, optionally, adding deionized water,

adding ammonia or ammonium hydroxide solution,

adjusting the pH of the solution to about 8-10 thereby forming a slurry containing a solid comprising an amino metal oxalate having the structure ##STR2## recovering said oxalate via filtration, and reacting said oxalate with water at a temperature of about 200°

C. to 250°

C. under pressure to yield an inorganic metal oxide powder.

2. The process of claim 1 wherein the amino metal oxalate contains a metal selected from the group consisting of zinc, tin, antimony mixed with tin, iron, zirconium, aluminum, chromium, yttrium and europium.

3. The process of claim 1 wherein said powder comprises:

at least one oxide of metals selected from the group of titanium, zirconium, silicon, aluminum, yttrium, europium, tin, antimony, iron, zinc, wherein said powder has an average crystallite size of about 1 to 100 nm.

4. The process of claim 1 wherein said process is performed in a non-oxidizing atmosphere.

5. The process of claim 1 wherein said process is performed in the presence of at least one dopant metal selected from the group consisting of tin, titanium, aluminum, antimony, zirconium, zinc, cerium, germanium, manganese, vanadium, ruthenium, iridium, osmium, tungsten, molybdenum, niobium, cobalt, lead, silicon, indium, tantalum, yttrium, europium, iron, copper and nickel;

wherein said metals and said dopant metals are chemically distinct.