Heterogeneously catalyzed lignin depolymerization

Biomass offers a unique resource for the sustainable production of bio-derived chemical and fuels as drop-in replacements for the current fossil fuel products. Lignin represents a major component of lignocellulosic biomass, but is particularly recalcitrant for valorization by existing chemical technologies due to its complex cross-linking polymeric network. Here, we highlight a range of catalytic approaches to lignin depolymerisation for the production of aromatic bio-oil and monomeric oxygenates

Medium of instruction ideologies: accommodation of multilingualism in the bilingual regime of Navarre

The management of bilingualism in the Spanish autonomous community of Navarre is a source of tension. The implementation of English medium of instruction in the public educational system has clashed with attempts to break with the linguistic territoriality regime by promoting Basque schooling. This paper brings together ideologies on English and minority languages and explores how political practice is intertwined with language policy and planning and language ideology. More specifically, it examines the institutionalization of language ideologies through language policy-making in education and, particularly, through medium of instruction. The paper begins with a description of the bilingual regime in Navarre and an examination of how ideologies have shaped and legitimized language policy in education. It then moves on to an analysis of both Basque and English medium of instruction ideologies that inform policy-making. This paper shows that the dynamics introduced by multilingualism in education have had a reinforcing effect on previous language ideologies on bilingualism and, ultimately, have aggravated the language dispute. Finally, it discusses how medium of instruction serves as a terrain for language competition and as part of a broader struggle for language policy and institutional power

Willow Lignin Oxidation and Depolymerization under Low Cost Ionic Liquid

Willow biomass was subjected to different pretreatment conditions with triethylammonium hydrogen sulfate as solvent, and the produced lignin solutions were treated by oxidation either homogeneously using H2O2 as oxidant or by heterogeneous catalysis using TiO2. Lignin, residual lignin, oil, and the recovered ionic liquid (IL) were characterized in order to determine the effects of each treatment. Lignin was successfully extracted and depolymerized by oxidation and characterized by ATR-IR, HPSEC, and py-GCMS. The obtained oil was characterized by GCMS; it was composed mainly of acids derived from the sugar and lignin fractions, the TiO2 catalyzed oils being richer in phenolic derived compounds than sugar fractions. The final ionic liquid was characterized in order to determine its suitability to be reutilized

Lignin oxidation and depolymerisation in ionic liquids

The depolymerisation of lignin directly in the black liquor was studied, comparing two ionic liquids as extracting solvents (butylimidazolium hydrogen sulphate and triethylammonium hydrogen sulphate), under oxidising conditions. H2O2 was chosen as the oxidant agent. It was observed that lignins derived from butylimidazolium hydrogen sulphate were more susceptible to degradation. The main degradation products found in the extracted oils were aromatic acids, such as vanillic acid, benzoic acid and 1,2-benzenedicarboxylic acid.Department of Education, Universities and Investigation of the Basque Government (project IT672-13

Oxidative Depolymerization of Lignin Using a Novel Polyoxometalate-Protic Ionic Liquid System

Oxidative depolymerization of lignin obtained from pine and willow can be achieved in a novel system encompassing the ionic liquid (IL) 1-butylimidazolium hydrogensulfate coupled with a vanadium based polyoxometalate (POM) under oxygen rich conditions. Along with an array of phenols and functionalized aromatics, vanillin and syringaldehyde were the main products extracted from the IL. The overall yield of aldehyde products were shown to be higher on lignin samples obtained with shorter pretreatment times, with vanillin being the exclusive aldehyde product obtained from pine. In the presence of molecular oxygen, the highest yield of aldehyde products was obtained when 5 wt % of the POM relative to the IL was employed and constituted the major product in the extracted oils. This system succeeds in exploiting the ability of ILs to depolymerize lignin and the remarkable properties of the POM to oxidize the lignin fragments into useful platform chemicals