The manipulation of the enone moiety associated with the biomass-derived, homochiral and now abundant compound levoglucosenone (1) is described. While the trichloroacetimidates derived from the allylic alcohols 3 and 4 failed to engage in Overman-type rearrangements, certain ester derivatives reacted in the presence of Pd[0]-catalysts to give regio-isomeric mixtures of beta,gamma-unsaturated malonates or ketones, the structures of which were confirmed by single-crystal X-ray analyses. In other sequences involving 1,3-transposition reactions, an operationally simple means for converting compound 1 into isolevoglucosenone (2) is described. [GRAPHICS] . (C) 2018 Published by Elsevier Ltd.

Levoglucosenone (LGO) is the major product formed when cellulose is pyrolyzed in the presence of acid at temperatures between 170 and 350 °C. The current intense interest in biomass conversion has led to a number of reports on its preparation; however, there is still uncertainty on the mechanism leading to LGO. We propose a new mechanism which involves a C2-C1 hydride shift followed by intramolecular trapping of a dioxyallyl cation. The reaction has been modeled using DFT calculations from the known LGO precursors levoglucosan and 1,4:3,6-dianhydro-α-D-glucopyranose to a common intermediate with calculated barriers of 10.6 and 13.5 kcal·mol-1, respectively. A discussion of the literature on the formation of LGO from late pathway intermediates is also provided.

Novel molecularly smooth, flat and thin films of regenerated bio-deuterated cellulose were produced for enhanced contrast with adsorbed molecules in neutron reflectivity (NR) and for cellulose structure studies. The cellulose films were produced to study both the solid/air interface and the solid/liquid interface. Cellulose films with a wide range of scattering contrast were achieved by combining exchange of 1 H for deuterium on hydroxyl groups via water in the liquid phase and via biosynthesis of deuterated bacterial cellulose by Gluconacetobacter xylinus which can deuterate the hydrogens bonded to carbon atoms in cellulose. The deuterated cellulose combined with NR will help to provide new information on the interaction of various (bio)-macromolecules and cellulose. This includes quantifying and visualizing the density profile of polymers and biomolecules adsorbed onto cellulose surface. The potential of this material for IR studies of materials adsorbed to cellulose films is briefly discussed.

Chiral epoxides—such as ethyl and methyl (S)-3-(oxiran-2-yl)propanoates ((S)-1a/1b)—are valuable precursors in many chemical syntheses. Until recently, these compounds were synthesized from glutamic acid in four steps (deamination, reduction, tosylation and epoxide formation) in low to moderate overall yield (20%–50%). Moreover, this procedure requires some harmful reagents such as sodium nitrite ((eco)toxic) and borane (carcinogen). Herein, starting from levoglucosenone (LGO), a biobased chiral compound obtained through the flash pyrolysis of acidified cellulose, we propose a safer and more sustainable chemo-enzymatic synthetic pathway involving lipase-mediated Baeyer-Villiger oxidation, palladium-catalyzed hydrogenation, tosylation and treatment with sodium ethoxide/methoxide as key steps. This route afforded ethyl and methyl (S)-3-(oxiran-2-yl)propanoates in 57% overall yield, respectively. To demonstrate the potentiality of this new synthetic pathway from LGO, the synthesis of high value-added (S)-dairy lactone was undertaken from these epoxides and provided the target in 37% overall yield from LGO.

Novel thin and smooth deuterated cellulose films were synthesised to visualize adsorbed bio-macromolecules using contrast variation neutron reflectivity (NR) measurements. Incorporation of varying degrees of deuteration into cellulose was achieved by growing Gluconacetobacter xylinus in deuterated glycerol as carbon source dissolved in growth media containing D2O. The derivative of deuterated cellulose was prepared by trimethylsilylation(TMS) in ionic liquid(1-butyl-3-methylimidazolium chloride). The TMS derivative was dissolved in toluene for thin film preparation by spin-coating. The resulting film was regenerated into deuterated cellulose by exposure to acidic vapour. A common enzyme, horseradish peroxidase (HRP), was adsorbed from solution onto the deuterated cellulose films and visualized by NR. The scattering length density contrast of the deuterated cellulose enabled accurate visualization and quantification of the adsorbed HRP, which would have been impossible to achieve with non-deuterated cellulose. The procedure described enables preparing deuterated cellulose films that allows differentiation of cellulose and non-deuterated bio-macromolecules using NR.

With the increasing restriction and control of hazardous solvents, safer alternatives need to be identified. Here a contemporary approach to solvent selection and substitution is presented that offers a more scientific alternative to the simple "like-for-like" exchange. A new family of levoglucosenone-derived compounds is proposed, modeled to determine their solvent properties, synthesized, and tested. These new molecules show promise as replacements for polar aprotic solvents that have chronic toxicity issues, such as dichloromethane, nitrobenzene, and N-methylpyrrolidinone. The success of this approach makes it possible for academia and industry to make calculated, intelligent choices for solvent substitution in the future.

The sustainability of biorefineries can be improved through levoglucosenone production from residual sugars in waste lignin.

Circa's proprietary Furacell (TM) technology is an industry-leading innovation that enables the manufacture of levoglucosenone (LGE), a potential platform chemical having a highly functional C6 structure, from a range of renewable waste and non-food source cellulosic feedstocks (e.g. straw, bagasse, sawdust). One use of LGE is conversion into a "green" alternative bio-solvent dihydrolevoglucosenone (known as Cyrene (TM)). Furacell (TM) is currently the only technology that allows production of LGE and Cyrene (TM) on a scalable basis.The Furacell (TM) process takes lignocellulosic material and uses a combination of catalysts and heat to form LGE, biochar and water. The vapours formed during the process are separated from the biochar, distilled and purified before subsequent catalytic hydrogenation to form (Cyrene (TM)). Cyrene (TM) is a renewable non-toxic solvent that has the potential for widespread use in the pharmaceutical and other industries.Following successful international market trials of Cyrene (TM), Circa and Norske Skog are now ready to build a 50 tpa developmental facility (FC5) to demonstrate to investors and customers a large-scale prototype before committing to a larger-scale commercial plant. In order to gain environmental approvals to construct FC5, an environmental effects report is required in which the composition and concentration of any compounds present are identified and their potential environmental effect predicted.The major process water components from the Furacell (TM) process have been identified by gas chromatography/mass spectrometry (GC/MS) analysis of earlier pilot plant streams to consist of short chain (<C5) C-O compounds, short chain (<C5) carboxylic acids, non-aromatic & aromatic cyclic compounds, plus minor amounts of product and catalyst that will not be retained within the proto-type plant. A proprietary mass-balance process model has been used to estimate the likely concentrations of the major process water components in effluent proceeding to biological treatment.The ability of these components to be degraded in a biological treatment process has been established from literature data, thus enabling the estimation of their final concentration in treated effluent. Published toxicity data for these components has been used to establish that the final treated effluent is not likely to have to any toxicity to aquatic species.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

Levoglucosenone (1), a compound that will soon be available in tonne quantities through the pyrolysis of acid-treated lignocellulosic biomass, has been converted into isolevoglucosenone (2) using Wharton rearrangement chemistry. Treatment of compound 1 with alkaline hydrogen peroxide gave the gamma-lactones 5 and 6 rather than the required epoxy-ketones 3 and/or 4. However, the latter pair of compounds could be obtained by an initial Luche reduction of compound 1, electrophilic epoxidation of the resulting allylic alcohol 8 and oxidation of the product oxiranes 9 and 10. Independent treatment of compounds 3 and 4 with hydrazine then acetic acid followed by oxidation of the ensuing allylic alcohols finally afforded isolevoglucosenone (2). Details of the single-crystal X-ray analyses of epoxy-alcohols 9 and 10 are reported.

Dihydrolevoglucosenone (Cyrene) is a bio-based molecule, derived in two simple steps from cellulose, which demonstrates significant promise as a dipolar aprotic solvent. The dipolarity of dihydrolevoglucosenone is similar to NMP, DMF and sulpholane. Dihydrolevoglucosenone demonstrates similar performance to NMP in a fluorination reaction and the Menschutkin reaction.

In preliminary laboratory experiments, heating recycled linerboard sheets in an oxygen-free atmosphere at 220 degrees C for 10 minutes reduced the basis weight (2%) as expected, had minimal effect on Cobb (+/- 4%), lowered water vapour transmission rate (WVTR) marginally (10%) but improved wet tensile strength and creep performance as judged by yield point. Identical treatment of paperboard made from virgin pulp had the same impact on basis weight, Cobb and wet tensile, but had no beneficial effect on WVTR or creep resistance. Briefer heating of the linerboard sheets by direct contact between heated plates at minimum pressure in air achieved similar results at much reduced contact times (less than 10 seconds). Because of the disparity between the response of linerboards made from virgin and recycled fibre, it was evident that partial pyrolysis of hemicellulose was unlikely to be the cause of the effect. The presence of starch in the test liner and its absence in the kraft linerboard therefore became the focus of further experiments. Treatment of kraft linerboard with 12% wheaten starch in a laboratory size press and subsequent heating at 220 degrees C for 10 seconds gave a 15% improvement in creep performance when compared to untreated linerboard. The data is interpreted in terms of partial dehydration of the anhydroglucose moieties within the starch, initially creating products that have undergone chemical dehydration and are either more impervious to water vapour themselves, or which undergo further reactions to form polymeric material that increases the covalent bonding between fibres. At present these observations remain a laboratory curiosity and a considerable engineering challenge remains in establishing whether or not sufficient heat can be applied economically to linerboard at commercial line speeds in a manner that will improve the visco-elastic performance without thermally degrading the cellulose present and reducing dry strength properties.

This paper reports two new methods for enhancing the peroxide bleaching of kraft pulps. The methods involve the use of an alkylguanidine or alkylurea as a peroxide activator in the presence of an inorganic stabiliser for wood pulp bleaching. The activators were evaluated on various kraft pulps and their performances compared with commercially used peroxide activators. The results showed that both activators greatly improved the performance of peroxide bleaching processes under relatively mild conditions, and they were found to be superior to commercially used peroxide activators under the conditions examined. Alkylurea performed better than alkylguanidine over a broader temperature range. The use of the alkylurea did not negatively affect pulp viscosity. Potential limitations of the methods are also discussed.

This paper introduces some improved methods for bleaching sulfite pulp and mechanical pulp with hydrogen peroxide, which involve the use of an additive or activator in conventional peroxide bleaching systems. It has been found in this investigation that a commercially available product, Prestogen W Liquid (BASF), is an effective additive for improving the bleaching of both sulfite pulp and mechanical pulp, but it does not seem to have a significant effect on kraft pulp bleaching. This product, containing an aliphatic dicarboxylic acid and chelating agents, has previously been used in the textile industry for enhancing the peroxide bleaching of wool under acidic to mildly alkali pH conditions, but it has not been identified as beneficial for use in paper pulp bleaching until now. 1,1-diethylurea (1,1-DEU), which is known to be an excellent peroxide activator for kraft pulp bleaching, has also been evaluated for bleaching of sulfite pulp and mechanical pulp. It has been found that 1,1-DEU has a positive effect on sulfite pulp bleaching, and it may also be used in combination with Prestogen W to further improve the brightness of sulphite pulp. However, 1,1-DEU has little effect on mechanical pulp bleaching.