Preparation of barium titanate or strontium titanate having a mean diameter of less than 10 nanometers

• US 7,223,378 B2
• Filed: 05/12/2003
• Issued: 05/29/2007
• Est. Priority Date: 05/14/2002
• Status: Expired due to Fees

• Current Assignee: BASF AG (BASF SE)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Sterzel, Hans-Josef
• Primary Examiner(s): Vanoy; Timothy C.
• Application Number:
  US10/435,457
• Publication Number:
  US 20030215384A1
• Time in Patent Office: 1,478 Days
• Field of Search: 423/598, 423/594.16, 423/69, 423/155, 423/71, 423/84, 361/321.1, 361/321.4, 361/321.5, 501/136, 501/137, 977/776, 977/811, 977/812
• US Class Current: 423/598
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: C01G 23/006 Alkaline earth titanates
• CPC Class Codes: C01P 2004/64 Nanometer sized, i.e. from 1-100 nanometer
• CPC Class Codes: C04B 2235/3213 Strontium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3215 Barium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3232 Titanium oxides or titanates, e.g. rutile or anatase
• CPC Class Codes: C04B 2235/3236 Alkaline earth titanates
• CPC Class Codes: C04B 2235/44 Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
• CPC Class Codes: C04B 2235/441 Alkoxides, e.g. methoxide, tert-butoxide
• CPC Class Codes: C04B 2235/5454 nanometer sized, i.e. below 100 nm
• CPC Class Codes: C04B 2235/549 the particle size being expressed by crystallite size or primary particle size
• CPC Class Codes: C04B 2235/608 Green bodies or pre-forms with well-defined density
• CPC Class Codes: C04B 2235/761 Unit-cell parameters, e.g. lattice constants
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/79 Non-stoichiometric products, e.g. perovskites (ABO3) with an A/B-ratio other than 1
• CPC Class Codes: C04B 35/6264 Mixing media, e.g. organic solvents
• CPC Class Codes: C04B 35/62655 Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying
• CPC Class Codes: H01G 4/1227 based on alkaline earth titanates

Abstract

Process for preparing barium titanate or strontium titanate by reacting titanium alkoxides with barium hydroxide hydrate or strontium hydroxide hydrate in a C₁–C₈-alcohol or a glycol ether at from 50 to 150° C.

Claims

1. A process for preparing barium titanate or strontium titanate, which comprises reacting titanium alkoxides with barium hydroxide hydrate or strontium hydroxide hydrate in a C₁–

C₈-alcohol or a glycol ether at from 50 to 150°

C., wherein no additional water apart from the water from the hydroxide hydrate is introduced into the reaction.

2. A process for preparing barium titanate or strontium titanate, which comprises reacting titanium alkoxides with barium hydroxide hydrate or strontium hydroxide hydrate in a C₁–

C₈-alcohol or a glycol ether at from 50 to 150°

C., wherein the barium hydroxide hydrate or strontium hydroxide hydrate is introduced into the solution in solid form.

3. A process for preparing barium titanate or strontium titanate comprising dissolving titanium alkoxides in a C₁–

C₈-alcohol or a glycol ether, and introducing barium hydroxide hydrate or strontium hydroxide hydrate thereto in solid form to react with said titanium alkoxide at from 50 to 150°

C., wherein the barium hydroxide hydrate or strontium hydroxide hydrate is introduced into the solution in solid form.