Purification of syringaldehyde and vanillin from an oxidized industrial kraft liquor by chromatographic processes

Recovery of low molecular weight compounds from alkaline pretreatment liquor via membrane separations

“…There are generally two downstream methods that are employed after filtration: (1) upgrading of the permeate via funneling toward a specific product such as adipic acid, 36,55 or (2) isolation of a specific aromatic species within the permeate via chromatography. 31 In the case of funneling, assuming all of LMW compounds in the permeate are converted to a single product, the 2-stage filtration cost (0.08 $ per kg LMW compounds) (Table 5) is small (4.5%) relative to the product selling price ($1.8 per kg for adipic acid). 55 In the case of chromatography, assuming all of the aromatics are recovered in isolated fractions, the 2-stage filtration cost (0.64 $ per kg of aromatic species) is approaching the final product value cost (reported to be as low as $1 per kg).…”

“…24,26 Lastly, the fractionation of lignin from alkaline liquors has been demonstrated by size exclusion chromatography; however, the process requires expensive high pressure equipment for continuous processing via simulated moving bed (SMB), and clarification of the APL is needed prior to processing to prevent stationary phase fouling. 26,30,31 Considering the above challenges, APL fractionation via membrane separations is a promising approach because membrane systems operate non-thermally, have a low energy demand, and are widely used industrially, thus offering a short developmental timeline via commercially available membranes and modules. 23,24,32 Membranes in the microfiltration (MF), ultrafiltration (UF), and nanofiltration (NF) range have been employed to recover defined molecular weight fractions from several lignin-rich streams.…”

High value-added lignin extracts from sugarcane by-products

“…Detection was performed at 268 nm and the volume of injection was 20 μL. GPC analysis was performed in isocratic mode employing dimethylformamide with 0.5 % w/v of lithium chloride [41]. Chromatograms were run at 70 • C and flowrate of 0.8 mL min − 1 .…”

Lignin alkaline oxidation using reversibly-soluble bases

“…Furthermore, the small amount of residual base in solution should be amenable to neutralization with CO 2 , precipitating SrCO 3 or BaCO 3 that could also be filtered and regenerated to the hydroxide, and thus leave a neutral-pH, low-salt monomer solution for separations or further upgrading. 16,27,62,63 The envisioned process is illustrated in Figure 1 and Figure S1.…”