Method for Fractional Separation of Lignin

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This patent presents a process for precise, stepwise separation (fractionation) of lignin from non-aqueous solutions, specifically using solvents like aliphatic cyclic ethers or lactones (such as 2-methyltetrahydrofuran). The process allows selective precipitation of lignin fractions by varying carbon dioxide pressures, which enables separation based on molecular weight and chemical composition. This method can provide highly purified lignin fractions derived from biomass, such as those from OrganoCat or Organosolv processes, with improved selectivity and environmental compatibility.

Use CasesContent extracted from patent full text and abstract with AI.

• Production of specialty lignin fractions for the creation of high-value chemicals, resins, or polymers from renewable biomass sources.
• Use in advanced material development, such as bioplastics, adhesives, coatings, carbon fibers, or composite materials, where specific lignin properties are desirable.
• Integration into biorefineries to valorize lignin byproducts from pulp and paper processing or biofuel manufacturing.
• Pharmaceutical or cosmetic industry applications, where well-defined, high-purity lignin fractions may be needed.
• Green chemistry applications, replacing petroleum-derived aromatic compounds with sustainable, selectively fractionated lignin.

BenefitsContent extracted from patent full text and abstract with AI.

• Enables highly specific and selective separation of lignin fractions based on molecular weight and structure, overcoming limitations of traditional unspecific isolation methods.
• Process operates under mild conditions using non-aqueous, potentially bio-based solvents and CO₂, resulting in lower environmental impact and increased sustainability.
• The solvents (like 2-methyltetrahydrofuran) are easily recyclable, improving process economy and reducing chemical waste.
• Generates lignin fractions with low polydispersity and well-controlled properties, improving the consistency and performance of lignin-based products.
• Facilitates the industrial use of lignin as a value-added renewable chemical, supporting bioeconomy and reducing dependence on fossil resources.

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Patent Abstract

The present invention relates to a process for fractionating precipitation of lignin from a nonaqueous solution, wherein, in a first process step a), the lignin is dissolved in a solvent selected from the group consisting of substituted or unsubstituted aliphatic cyclic ethers or lactones or a mixture of these solvents and, in a second process step b), the lignin is precipitated selectively from the solution by injection of carbon dioxide to different pressures at least as a function of the molecular weight and/or as a function of the lignin composition.