TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalyst: The ultra-fine gold particles are at most 10 nm. The titanium-containing oxide is titanium oxide, a titanium-containing complex oxide and/or a titanium-containing silicate.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Materials: The reducing agent is carbon monoxide, nitrogen monoxide, dinitrogen monoxide, alcohols, aldehydes, phenols, formic acids, oxalic acids and/or cyclohexadienes. EXAMPLE - Chloroauric acid.4 hydrate (1g) was dissolved in 1200 ml of distilled water, heated to 70 degreesC and adjusted to pH 7.5 with 0.1M NaOH as a buffer. Titanium-containing silicate (6 g, mesoporous silica replaced by titanium atoms, Ti:Si atomic ratio of 3:100)) was added with vigorous stirring, with continued stirring for 1 hour to induce precipitation of gold hydroxide on the titanium-containing silicate. The suspension was left to stand and cooled to room temperature before removing the supernatant.    3000 ml of distilled water was added, the mixture stirred (room temperature/5 minutes), and the supernatant was removed after standing. After repeating the washing step several times, the resulting paste was vacuum-dried (room temperature/12 hours), then fired in air (400 degreesC/4 hours) to give a catalyst comprising ultra-fine gold particles supported on the Ti-containing silicate. Analysis showed that the amount of the gold supported on the Ti-containing silicate was 1.2 wt.%. The catalyst was pretreated with a mixed gas (Ar/O2 in 7:1 proportion) at 300 degreesC for 1 hour. Partial oxidation of propylene was conducted at 100 degreesC in the presence of 0.5g of the catalyst using a fixed-bed reactor, fed with a mixed gas consisting of argon (70 vol.%), O2 (10 vol.%), carbon monoxide (10 vol.%) and propylene (10 vol.%). The space velocity was 4000 h-1.ml/g.cat. One hour after the initiation of the reaction, the following were determined: 0.39 % propylene conversion; 22 % CO conversion; 8.3 % acrolein selectivity; and 27 % propylene selectivity.