Bulk gold powder (∼10³ nm particle size) is a highly active catalyst for the oxidative dehydrogenation of secondary amines to imines under the mild conditions of 1 atm O₂ and 60–100 °C.

Silver (Ag⁺) salts adsorbed on amorphous silica or mesoporous SBA-15 extract dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-Me₂DBT) from simulated, hydrotreated petroleum feedstocks.

Oxidative reactions that are catalysed by bulk gold consisting of ∼50 000 nm gold powder particles or gold (∼50 nm) supported on Al₂O₃ are reviewed. Using O₂ as the oxidizing agent, bulk gold catalyzes the following types of reactions in organic solvents at 45–90 °C: (1) the conversion of amines to imines [(RCH₂)₂NH → RCH₂NCHR], (2) the oxidation of benzyl alcohol to benzaldehyde, (3) the reaction of isocyanides with primary amines to give carbodiimides [CN–R + H₂N–R′ → R′–NCN–R] and with secondary amines to give ureas , (4) the reactions of CO with primary amines to give ureas [CO + H₂N–R → OC(NHR)₂], and (5) the reactions of diazoalkanes with amines to give enamines . In some of these reactions, amine oxides (e.g., Me₃N–O) may be used in place of O₂. Mechanisms of these and related reactions are examined. These studies show that bulk, non-nanogold is capable of catalysing a variety of different reactions.