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CA-3128675-C - MODIFIED SULFURIC ACID AND USES THEREOF

CA3128675CCA 3128675 CCA3128675 CCA 3128675CCA-3128675-C

Abstract

An aqueous composition comprising: sulfuric acid; a substituted aromatic compound; and a peroxide. Said composition being capable of delignifying biomass under milder conditions than conditions under which kraft pulping takes place.

Inventors

  • Clay PURDY
  • Markus WEISSENBERGER
  • Markus Pagels
  • Kyle G. WYNNYK

Assignees

  • SIXRING INC.

Dates

Publication Date
20260505
Application Date
20210820
Priority Date
20210225

Claims (6)

  1. CLAIMS 1. An aqueous composition for use in the delignification of wood, wherein said composition comprises: - sulfuric acid; - a substituted aromatic compound; and - a peroxide wherein the sulfuric acid and the substituted aromatic compound are present in a mole ratio ranging from 2: 1 to 28:1.
  2. 2. An aqueous composition for use in the processing and depolymerisation of cellulose from a plant source, wherein said composition comprises: - sulfuric acid present in an amount ranging from 20 - 80 wt% of the total weight of the composition; - a substituted aromatic compound; and - a peroxide; wherein the sulfuric acid and the substituted aromatic compound are present in a mole ratio ranging from 2: 1 to 28:1.
  3. 3. The composition according to any one of claims 1 to 2, where the peroxide is hydrogen peroxide.
  4. 4. Method of delignification of plant material, said method comprising: - providing said plant material comprising cellulose fibers and lignin; - exposing said plant material requiring to a composition comprising: o sulfuric acid present in an amount ranging from 20 - 70 wt% of the total weight of the composition; and o a substituted aromatic compound; for a period of time sufficient to remove at least 80% of the lignin present on said plant material.
  5. 5. Method according to claim 4 where said substituted aromatic compound has a molecular weight below 300 g/mol.
  6. 6. Method according to any one of claims 4 and 5 where said composition further comprises a peroxide. 12 Date Re9ue/Date Received 2024-04-04 7. Method according to any one of claims 4 to 6 wherein said substituted aromatic compound comprises at least one amine moiety and at least one sulfonic acid group. 8. The method according to any one of claims 4 to 7 where said substituted aromatic compound is selected from the group consisting of: sulfanilic acid; metanilic acid; orthanilic acid; and combinations thereof. 9. The method according to any one of claims 4 to 8, wherein sulfuric acid and said substituted aromatic compound are present in a molar ratio ranging from 28: 1: to 2: 1. 10. The method according to any one of claims 4 to 9, wherein sulfuric acid and said substituted aromatic compound are present in a molar ratio ranging from 20: 1: to 5: 1. 11. The method according to any one of claims 4 to 10, wherein sulfuric acid and said substituted aromatic compound are present in a molar ratio of approximately 10: 1. 12. The method according to any one of claims 4 to 11, wherein the period of time is sufficient to remove at least 90% of the lignin present on said plant material. 13. The method according to any one of claims 4 to 12, wherein the period of time is sufficient to remove at least 95% of the lignin present on said plant material. 14. The method according to any one of claims 4 to 13, wherein said method is carried out at ambient temperature. 15. The method according to any one of claims 4 to 14, wherein said method is carried out at atmospheric pressure. 16. An aqueous acidic composition comprising: - sulfuric acid; - a substituted aromatic compound; and - a peroxide; wherein said substituted aromatic compound comprises aromatic compound having a sulfonamide substituent. 13 Date Re9ue/Date Received 2024-04-04 17. The aqueous acidic composition according to claim 16, where the substituted aromatic compound comprises aromatic compound having a sulfonamide substituent is selected from the group consisting of: benzenesulfonamides; toluenesulfonamides; substituted benzenesulfonamides; and substituted toluenesulfonamides. 18. A one-pot process to separate lignin from a lignocellulosic feedstock, said process comprising the steps of: - providing a vessel; - providing said lignocellulosic feedstock; - providing a composition comprising; - an acid; - a modifying agent comprising a substituted aromatic compound; and - a peroxide; - exposing said lignocellulosic feedstock to said composition in said vessel for a period of time sufficient to remove at least 80% of the lignin present said lignocellulosic feedstock; - optionally, removing a liquid phase comprising dissolved lignin fragments from a solid phase comprising cellulose fibres. 14 Date Re9ue/Date Received 2024-04-04

Description

MODIFIED SULFURIC ACID AND USES THEREOF FIELD OF THE INVENTION The present invention is directed to a method and composition useful in decomposing organic material by oxidation such as, but not limited to, the delignification of wood or plant substance, as an example and more specifically, to a method and composition for performing such under more optimal conditions than those under which the kraft process is currently conducted. BACKGROUND OF THE INVENTION The first step in paper production and most energy-intensive one is the production of pulp. Notwithstanding water, wood and other plant materials used to make pulp contain three main components: cellulose fibers; lignin; and hemicelluloses. Pulping has a primary goal to separate the fibers from the lignin. Lignin is a three-dimensional polymer which figuratively acts as a mortar to hold all the fibers together within the plant. Its presence in finished pulp is undesirable and adds nothing to the finished product. Pulping wood refers to breaking down the bulk structure of the fiber source, be it chips, stems or other plant parts, into the constituent fibers. The cellulose fibers are the most desired component when papermaking is involved. Hemicelluloses are shorter branched polysaccharide polymers consisting of various sugar monosaccharides which form a random amorphous polymeric structure. The presence of hemicellulose in finished pulp is also regarded as bringing no value to a paper product. This is also true for biomass conversion. The challenges are similar. Only the desired outcome is different. Biomass conversion would have the further breakdown to monosaccharides as a desired outcome while a pulp & paper process normally stops right after lignin dissolution. There are two main approaches to preparing wood pulp or woody biomass: mechanical treatment and chemical treatment. Mechanical treatment or pulping generally consists of mechanically tearing the wood chips apart and, thus, tearing cellulose fibers apart in an effort to separate them from each other. The shortcomings of this approach include: broken cellulose fibers, thus shorter fibers and lignin being left on the cellulose fibers thus being inefficient or non-optimal. This process also consumes large amounts of energy and is capital intensive. There are several approaches included in chemical pulping. These are generally aimed at the degradation the lignin and hemicellulose into small, water-soluble molecules. These now degraded components can be separated from the cellulose fibers by washing the latter without depolymerizing the cellulose fibers. The chemical process is currently energy intensive as well as high amounts of heat and / or higher pressures are typically required; in many cases, agitation or mechanical intervention are also required, further adding inefficiencies and costs to the process. 1 Date Re9ue/Date Received 2021-08-20 There exist pulping or treatment methods which combine, to a various extent, the chemical aspects of pulping with the mechanical aspects of pulping. To name a few, one must consider include thermomechanical pulping (also commonly referred to as TMP), and chemi-thermomechanical pulping (CTMP). Through a selection of the advantages provided by each general pulping method, the treatments are designed to reduce the amount of energy required by the mechanical aspect of the pulping treatment. This can also directly impact the strength or tensile strength degradation of the fibers subjected to these combination pulping approaches. Generally, these approaches involve a shortened chemical treatment ( compared to conventional exclusive chemical pulping) which is then typically followed by mechanical treatment to separate the fibers. The most common process to make pulp for paper production is the kraft process. In the kraft process, wood chips are converted to wood pulp which is almost entirely pure cellulose fibers. The multi-step kraft process consists of a first step where wood chips are impregnated / treated with a chemical solution. This is done by soaking the wood chips and then pre-heating them with steam. This step swells the wood chips and expels the air present in them and replaces the air with the liquid. This produces black liquor a resultant by-product from the kraft process. It contains water, lignin residues, hemicellulose and inorganic chemicals. White liquor is a strong alkaline solution comprising sodium hydroxide and sodium sulfide. Once the wood chips have been soaked in the various chemical solutions, they undergo cooking. To achieve delignification in the wood chips, the cooking is carried out for several hours at temperatures reaching up to l 76°C. At these temperatures, the lignin degrades to yield water soluble fragments. The remaining cellulosic fibers are collected and washed after the cooking step. US patent number 5,080,756 teaches an improved kraft pulping process and is characterized by the addition of a spent concentrated sulfuric acid