Electro-catalytic oxidative cleavage of lignin in a protic ionic liquid

Abstract

Lignin is a component of lignocellulosic biomass and a promising matrix for recovering important renewable aromatic compounds. We present a new approach of electro-oxidative cleavage of lignin, dissolved in a special protic ionic liquid, using an anode with particular electro-catalytic activity. As appropriate ionic liquid triethylammonium methanesulfonate was identified, synthesised, explored for dissolution of alkali-lignin and used for electrolysis of 5 wt.% lignin solutions. As appropriate anode material, oxidation-stable ruthenium-vanadium-titanium mixed oxide electrodes were prepared and explored for their electro-catalytic activity. The electrolysis was performed at several potentials in the range from 1.0 V to 1.5 V (vs. an Ag pseudo reference electrode). A wide range of aromatic fragments was identified as cleavage products by means of GC-MS and HPLC measurements.

Ionic Liquids for Lignin Processing: Dissolution, Isolation, and Conversion

“…As the b-O-4 bond has been reported as the dominant crosslink, comprising ,45-60 % of all monomer linkages present in lignin, most studies have focussed on disruption of the b-O-4 bond in synthesized model compounds. [73,74] Cleavage of two b-O-4-containing model compounds, the phenol-based guaiacylglycerol-b-guaiacyl ether (GG) and anisole-based veratrylglycerol-b-guaiacyl ether (VG), was reported by Jia et al using metal chlorides in [Bmim]Cl containing ,2 wt-% H 2 O. [74] FeCl 3 , CuCl 2 , and AlCl 3 were reported to be effective catalysts for cleaving the b-O-4 linkage, i.e.…”

Protic Ionic Liquids: Evolving Structure–Property Relationships and Expanding Applications

“…385 Triethylammonium methanesulfonate was selected as a low viscosity, high conductivity solvent for dissolving lignocellulosic biomass. 388 Electro-oxidative cleavage of this solution resulted in a wide range of aromatic fragments. The ability of the PIL to dissolve the lignin was attributed to the sulfate component of the anion.…”

New Development of Anodic Electro-catalyst for Chlor-alkali Industry

“…Ruthenium based electro catalytic anodes find applications in water electrolysis, electroorganic synthesis and electrochemical oxidation. [9][10][11]. Such types of anodes are used in caustic-chlorine cells, chlorate cells, sea water electrolysis and similar applications.…”

“…Technical innovation to improve the energy-efficiency and resource-efficiency in the chlor-alkali industry has become a critical issue in view of the current energy and environmental challenges being faced and the increasing shortages in the primary resources [15]. An attempt was made to reduce the electrode potential by about 100 mV (about 3-4% energy saving) and to reduce the ruthenium content [9][10][11]. The work presented in this paper aims to develop new anodic electro catalysts by using a titanium substrate, determine the optimum ruthenium oxide based electro catalytic coating composition, and subject the specimen to an optimized coating composition for current efficiency measurement to a pilot plant of 1.3 kg capacity of sodium chlorate per day.…”