No abstract

Herein, we report for the first time a synthetic method for the encapsulation of metal nanoparticles within porous liquids.

The unusual combination of characteristics observed for porousl iquids, which are typicallya ssociatedw ith either porous solids or liquids, has led to considerablei nterest in this new class of materials. However,t hese porous liquids have so far only been investigated for their ability to separate ands tore gases.H erein, the catalytic capability of Pt nanoparticles encapsulated within aT ype Ip orousl iquid (Pt@HS-SiO 2 PL)i se xplored for the hydrogenation of several alkenesa nd nitroarenes under mild conditions (T = 40 8C, P H2 = 1atm). The different intermediates in the porousl iquid synthesis (i.e.,t he initial Pt@HS-SiO 2 ,t he organosilane-func-tionalized intermediate, andt he final porousl iquid)a re employeda sc atalysts in order to understand the effect of each component of the porous liquid on the catalysis. For the hydrogenation of 1-decene, the Pt@HS-SiO 2 PL catalysti ne thanol has the fastestr eactionr ate if normalized with respect to the concentrationo fP t. The reaction rate slows if the reactioni sc ompleted in a" neat" porous liquid system,p robably because of the high viscosity of the system.T hese systems may find application in cascade reactions, in particular, for those with mutually incompatible catalysts.

Using a focused microwave reactor, methylation with dimethyl carbonate (DMC) of 1,2-and 1,4-dihydroxybenzene derivatives, found in the product spectrum of lignin depolymerisation, leads to the respective aromatic bis-methyl ethers with excellent isolated yields. Stoichiometric as well as catalytic amounts of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are effective for the bis-methylation of these dihydroxybenzenes at relatively mild temperatures (160-190 C). Conversion of resorcinol (1,3-dihydroxybenzene) under similar conditions leads to a mixture of 1,3-dimethoxybenzene and methyl 2,4-dimethoxybenzoate. The unusual reactivity of resorcinol's phenyl ring towards DMC can be explained by the synergic effect of its two strongly activating ortho/para directing groups.

N,N,N-Trimethyl chitosan (TMC) is one chitosan derivative that, because of its improved solubility, has been studied for industrial and pharmaceutic applications. Conventional methods for the synthesis of TMC involve the use of highly toxic and harmful reagents, such as methyl iodide and dimethyl sulfate (DMS). Although the methylation of dimethylated chitosan to TMC by dimethyl carbonate (DMC, a green and benign methylating agent) was reported recently, it involved a formaldehyde-based procedure. In this paper we report the single-step synthesis of TMC from chitosan using DMC in an ionic liquid. The TMC synthesised was characterised by 1H NMR spectroscopy and a functionally meaningful degree of quaternisation of 9% was demonstrated after a 12-h reaction time.