In a supported ionic liquid phase (SILP) catalyst system, an ionic liquid (IL) film is immobilized on a high-surface area porous solid and a homogeneous catalyst is dissolved in this supported IL layer, thereby combining the attractive features of homogeneous catalysts with the benefits of heterogeneous catalysts. In this review reliable strategies for the immobilization of molecular catalysts in SILPs are surveyed. In the first part, general aspects concerning the application of SILP catalysts are presented, focusing on the type of catalyst, support, ionic liquid and reaction conditions. Secondly, organic reactions in which SILP technology is applied to improve the performance of homogeneous transition-metal catalysts are presented: hydroformylation, metathesis reactions, carbonylation, hydrogenation, hydroamination, coupling reactions and asymmetric reactions.

Various carbamates can be prepared in a halogen-free way starting from cheap and readily available reagents such as amines, alcohols and carbon dioxide. Basic catalysts were able to convert both linear and branched aliphatic amines to the corresponding carbamates with good yields, in mild reaction conditions (2.5 MPa CO 2 ) and even in the absence of dehydrating agents.

The depolymerization of cellulose is carried out in the ionic liquid 1-butyl-3-methylimidazolium chloride in the presence of hydrogen gas. First, the ketal 1,1-diethoxycyclohexane and cellobiose were used as model substrates. For the depolymerization of cellulose itself, the combination of a heterogeneous metal catalyst and a homogeneous ruthenium catalyst proved effective. One of the possible roles of the ruthenium compound is to enhance the transfer of hydrogen to the metallic surface. The cellulose is fully converted under relatively mild conditions, with sorbitol as the dominant product in 51-74% yield.

BACKGROUND Until now ionic liquid research concerning lignin dissolution and processing has mainly focused on the imidazolium type ionic liquids. Other types of ionic liquids can extend the scope of such processes due to their better thermal, base and oxidation stability. RESULTS A series of ammonium, phosphonium and pyrrolidinium based ionic liquids was screened for lignin dissolution. Tributylmethylphosphonium methyl sulfate and N‐butyl‐N‐methylpyrrolidinium dicyanamide displayed the highest Kraft lignin dissolution at 90 °C, with 460 and 390 g kg‐1, respectively. The latter ionic liquid combines this high solubility with a rather low viscosity, resulting in a promising medium for processing lignin and for other potential applications in wood separation technology. Owing to the ionic character of lignosulfonate, its solubility was even higher. The molecular structures of both recovered lignin and ionic liquid were not changed after lignin dissolution, as proven with FT‐IR, Curie‐point pyrolysis‐GC/MS and NMR. The ionic liquid could be recycled without loss in lignin dissolving ability. CONCLUSION Ammonium, phosphonium, and pyrrolidinium based ionic liquids proved suitable for lignin dissolution, if combined with the right counterion. © 2014 Society of Chemical Industry

The conversion of cellulose into alkylglycosides is carried out in the ionic liquid 1-butyl-3-methylimidazolium chloride in the presence of an acidic catalyst. Primary alcohols like n-butanol and n-octanol were used as alkylating reagents. The acidic resin Amberlyst 15DRY proved to be the optimum heterogeneous catalyst: it catalyzes the hydrolysis of the b(1→4) links in the cellulose polymeric chain as well as the alkylation of the hydroxyl groups at the C1 position of the glucose intermediate. The cellulose was fully converted under mild conditions; in a reaction with n-butanol, the obtained yield of butylglucopyranoside isomers was 86%.