Cooperative Reduction: Selective redox transformation remains a general challenge in chemical synthesis. All too often, the most readily available precursor to a compound must be over-reduced (or over-oxidized) and then carefully coaxed back to a desired intermediate state. Such is the case with the synthesis of cyclohexanone, which is mass-produced for use in the preparation of nylon: Access by direct reduction of phenol is plagued by the rapid addition of too many hydrogen atoms to the substrate, producing an alcohol (cyclohexanol) in place of the ketone. Liu et al. (p. 1250 ) have discovered that the unexpected cooperation of supported palladium and a Lewis acid such as aluminum trichloride—two catalysts widely used alone but rarely in concert—facilitates highly selective conversion of phenol to cyclohexanone near room temperature. The key appears to be inhibition of the undesired ketone-to-alcohol reduction step by the Lewis acid.

Cellulose/KI is a very active, selective, stable, and recyclable catalyst for the cycloaddition reactions of CO₂ and epoxides due to the excellent synergetic effect of cellulose and KI. It is found that the hydroxyl groups on the vicinal carbons of cellulose play a key role for the very high efficiency of the catalyst.

In this work, the catalytic efficiency of ionic liquid (IL) choline chloride/urea supported on molecular sieves for the reactions of CO₂ and epoxides was studied under different conditions. It was demonstrated that this biodegradable and green catalyst is very active and selective, and choline chloride and urea showed a synergetic effect in promoting these reactions. After reaction, the solid catalyst and the products could be separated easily because the IL was insoluble in the products, and the catalyst was reusable. The origin of the high catalytic efficiency and the reaction mechanism were also discussed.

The synthesis of disubstituted ureas from amines and CO₂ were carried out using a basic ionic liquid (IL) 1-n-butyl-3-methyl imidazolium hydroxide ([Bmim]OH) as the catalyst. The effects of reaction time, amount of [Bmim]OH, reaction temperature, pressure, and solvent on yields of the products were investigated. The results indicated that aliphatic amines, cyclohexylamine, and benzylamine could be converted to the corresponding ureas selectively in moderate yields under solvent-free conditions without using any dehydrating regent. The IL could be reused after a simple separation procedure.

Glycerol is a well-known renewable chemical, and its effective transformation to valuable chemicals accords well with the principles of green chemistry. In this work, a series of Ru-Cu bimetallic catalysts were prepared using cheap and abundant clay, bentonite, as the support. Bentonite was modified with a functional ionic liquid 1,1,3,3-tetramethylguanidinium lactate (TMGL) in an attempt to develop highly efficient catalysts. Hydrogenolysis of aqueous solution of glycerol was performed with the immobilized Ru-Cu catalyst under temperatures of 190–240 °C and pressures of 2.5–10 MPa. The bimetallic catalysts were very efficient for promoting the hydrogenolysis of glycerol. 100% of glycerol conversion and 85% yield of 1,2-propanediol could be achieved at 230 °C and 8 MPa. The conversion of glycerol and the selectivity to 1,2-propanediol did not decrease after the catalyst was used 5 times. TMGL played a crucial role in fabricating the new catalysts. The catalysts were characterized by FT-IR, XPS, SEM and TEM, and the reasons for the excellent performances of the catalyst were also discussed.