MODIFIED SULFURIC ACID AND USES THEREOF
20210269970 · 2021-09-02
Inventors
- Clay Purdy (Medicine Hat, CA)
- Markus Weissenberger (Calgary, CA)
- Kyle G. Wynnyk (Calgary, CA)
- Karl W. Dawson (Calgary, CA)
Cpc classification
D21C3/06
TEXTILES; PAPER
International classification
Abstract
A modified aqueous acid composition comprising: sulfuric acid; a compound comprising an amine moiety and a sulfonic acid moiety; and a peroxide; wherein sulfuric acid, said compound comprising an amine moiety and a sulfonic acid moiety and said peroxide are present in a molar ratio of no less than 1:1:1. Also disclosed are methods of using such compositions.
Claims
1. A modified aqueous acid composition comprising: sulfuric acid; a compound comprising an amine moiety and a sulfonic acid moiety; and a peroxide; wherein said sulfuric acid, said compound comprising an amine moiety and a sulfonic acid moiety, and said peroxide are present in the composition in a molar ratio of no less than 1:1:1.
2. The composition according to claim 1, wherein said sulfuric acid, said compound comprising an amine moiety and a sulfonic acid moiety, and said peroxide are present in the composition in a molar ratio of no more than 15:1:1.
3. (canceled)
4. The composition according to claim 1, wherein said compound comprising an amine moiety and a sulfonic acid moiety is selected from taurine, taurine derivatives, and taurine-related compounds.
5. The composition according to claim 1, wherein said compound comprising an amine moiety and a sulfonic acid moiety is a taurine derivative or taurine-related compound selected from sulfamic acid, taurolidine taurocholic acid, tauroselcholic acid, tauromustine, 5-taurinomethyluridine, and 5-taurinomethyl-2-thiouridine, homotaurine (tramiprosate), acamprosate, a taurate and an aminoalkylsulfonic acid wherein the alkyl in said aminoalkylsulfonic acid is selected from C1-C5 linear alkyl and C1-C5 branched alkyl.
6. The composition according to claim 1, wherein said compound comprising an amine moiety and a sulfonic acid moiety is a linear aminoalkylsulfonic acid selected from methyl, ethyl, n-propyl, and n-butyl.
7. The composition according to claim 1, wherein said compound comprising an amine moiety and a sulfonic acid moiety is a C1-C5 branched aminoalkylsulfonic acid selected from isopropyl, isobutyl, and isopentyl.
8. The composition according to claim 1, wherein said compound comprising an amine moiety and a sulfonic acid moiety is taurine.
9. The composition according to claim 1, wherein said sulfuric acid and said compound comprising an amine moiety and a sulfonic acid moiety are present in the composition in a molar ratio of no less than 3:1.
10. The composition according to claim 1, wherein said sulfuric acid in a is present in the composition in an amount ranging from 20-70 wt % of the total weight of the composition; and said compound comprising an amine moiety and a sulfonic acid moiety is selected from taurine, taurine derivatives, and taurine-related compounds.
11. The composition according to claim 1, wherein said sulfuric acid in a is present in the composition in an amount ranging from 40-80 wt % of the total weight of the composition; said compound comprising an amine moiety and a sulfonic acid moiety is selected from taurine, taurine derivatives, and taurine-related compounds; and said sulfuric acid and said compound comprising an amine moiety and a sulfonic acid moiety are present in the composition in a mole ratio ranging from 3:1 to 15:1.
12. (canceled)
13. An aqueous composition comprising: sulfuric acid present in the composition in an amount ranging from 20-70 wt % of the total weight of the composition; a compound comprising an amine moiety and a sulfonic acid moiety selected from taurine, taurine derivatives, and taurine-related compounds; and a peroxide; wherein said sulfuric acid and said compound comprising an amine moiety and a sulfonic acid moiety are present in the composition in a mole ratio ranging from 3:1 to 15:1; and wherein said composition is suitable for breaking down cellulose in a plant biomass source.
14. (canceled)
15. The composition according to claim 13, wherein said taurine, taurine derivatives, and taurine-related compounds are selected from sulfamic acid, taurolidine, taurocholic acid, tauroselcholic acid, tauromustine, 5-taurinomethyluridine, 5-taurinomethyl-2-thiouridine, homotaurine (tramiprosate), acamprosate, a taurate, and an aminoalkylsulfonic acid, wherein the alkyl in said aminoalkylsulfonic acid is selected from C1-C5 linear alkyl and C1-C5 branched alkyl.
16. The composition according to claim 13, wherein said compound comprising an amine moiety and a sulfonic acid moiety is taurine.
17. The composition according to claim 13, wherein said peroxide is hydrogen peroxide.
18. A method of delignifying plant biomass or biomass material, said method comprising: providing said plant biomass or biomass material comprising cellulose fibers and lignin; and exposing said plant biomass or biomass material to a composition comprising: sulfuric acid present in the composition in an amount ranging from 20-70 wt % of the total weight of the composition; a compound comprising an amine moiety and a sulfonic acid moiety selected from taurine, taurine derivatives, and taurine-related compounds; and a peroxide; for a period of time sufficient to remove substantially all lignin present on said plant biomass or biomass material.
19. The method according to claim 18, wherein said taurine derivative or taurine-related compound is selected from sulfamic acid, taurolidine, taurocholic acid, tauroselcholic acid, tauromustine, 5-taurinomethyluridine, 5-taurinomethyl-2-thiouridine, homotaurine (tramiprosate), acamprosate, a taurate, and an aminoalkylsulfonic acid wherein the alkyl in said aminoalkylsulfonic acid is selected from C1-C5 linear alkyl and C1-C5 branched alkyl.
20. The method according to claim 18, wherein said sulfuric acid and said compound comprising an amine moiety and a sulfonic acid moiety are present in the composition in a molar ratio of no less than 3:1.
21. The method according to claim 18, wherein said peroxide is hydrogen peroxide.
22. A modified acid composition comprising: sulfuric acid; and a compound comprising an amine moiety and a sulfonic acid moiety; wherein said sulfuric acid and said compound comprising an amine moiety and a sulfonic acid moiety are present in the composition in a molar ratio of no less than 3:1.
23. The composition according to claim 22, wherein said compound comprising an amine moiety and a sulfonic acid moiety is selected from taurine, taurine derivatives, and taurine-related compounds.
24. The composition according to claim 22, wherein said compound comprising an amine moiety and a sulfonic acid moiety is a taurine derivative or taurine-related compound selected from sulfamic acid, taurolidine, taurocholic acid, tauroselcholic acid, tauromustine, 5-taurinomethyluridine, 5-taurinomethyl-2-thiouridine, homotaurine (tramiprosate), acamprosate, a taurate, and an aminoalkylsulfonic acid wherein the alkyl in said aminoalkylsulfonic acid is selected from C1-C5 linear alkyl and C1-C5 branched alkyl.
Description
4. BRIEF DESCRIPTION OF THE FIGURES
[0048] The invention may be more completely understood in consideration of the following description of various embodiments of the invention in connection with the accompanying figures, in which:
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5. DESCRIPTION OF THE INVENTION
[0065] The experiments carried out using an aqueous acidic composition according to a preferred embodiment of the present invention has shown that woody biomass can be delignified under controlled reaction conditions and eliminate, or at least minimize, the degradation of the cellulose. Degradation is understood to mean a darkening of cellulose or carbonization (conversion to carbon black) which is symbolic of an uncontrolled acid attack on the cellulose and staining thereof
[0066] Preferably, a composition according to the present invention comprises:
[0067] sulfuric acid; and
[0068] a compound comprising an amine moiety and a sulfonic acid moiety selected from the group consisting of: taurine; taurine derivatives and taurine-related compounds.
[0069] Preferably, the taurine derivatives and taurine-related compounds are understood to include: sulfamic acid; taurolidine; taurocholic acid; tauroselcholic acid; tauromustine; 5-taurinomethyluridine and 5-taurinomethyl-2-thiouridine; homotaurine (tramiprosate); acamprosate; and taurates; as well as aminoalkylsulfonic acids where the alkyl is selected from the group consisting of C1-C5 linear alkyl and C1-C5 branched alkyl. Preferably, the linear alkylaminosulfonic acid is selected form the group consisting of: methyl; ethyl (taurine); propyl; and butyl. Preferably, the branched aminoalkylsulfonic acid is selected from the group consisting of: isopropyl; isobutyl; and isopentyl.
[0070] According to a preferred embodiment, the taurine derivatives and taurine-related compounds are selected from the group consisting of: taurolidine; taurocholic acid; tauroselcholic acid; tauromustine; 5-taurinomethyluridine and 5-taurinomethyl-2-thiouridine; homotaurine (tramiprosate); acamprosate; and taurates.
[0071] Most preferably, the compound comprising an amine moiety and a sulfonic acid moiety is taurine.
[0072] When performing delignification of wood using a composition according to a preferred embodiment of the present invention, the process can be carried out at substantially lower temperatures than temperatures used in the conventional kraft pulping process. The advantages are substantial, here are a few: the current kraft pulping process requires temperatures in the vicinity of 176-180° C. in order to perform the delignification process, a preferred embodiment of the process according to the present invention can delignify wood at far lower temperatures, even as low as 20° C. in some cases. According to a preferred embodiment of the present invention, the delignification of wood can be performed at temperatures as low as 0° C. According to a preferred embodiment of the present invention, the delignification of wood can be performed at temperatures as low as 10° C. According to a preferred embodiment of the present invention, the delignification of wood can be performed at temperatures as low as 30° C. According to another preferred embodiment of the present invention, the delignification of wood can be performed at temperatures as low as 40° C. According to yet another preferred embodiment of the present invention, the delignification of wood can be performed at temperatures as low as 50° C. According to yet another preferred embodiment of the present invention, the delignification of wood can be performed at temperatures as low as 60° C.
[0073] In each one of the above preferred embodiments, the temperature at which the processes are carried out are substantially lower than the current energy-intensive and inefficient kraft process.
[0074] Moreover, the kraft process uses high pressures to perform the delignification of wood which is initially capital intensive, dangerous, expensive to maintain, and has high associated turn-around or maintenance costs. According to a preferred embodiment of the present invention, the delignification of wood can be performed at atmospheric pressure. This, in turn, circumvents the need for highly specialized and expensive industrial equipment such as pressure vessels/digestors. It also allows the implementation of delignification units in many parts of the world where the implementation of a kraft plant would previously be impracticable due to a variety of reasons.
[0075] Some of the advantages of a process according to a preferred embodiment of the present invention, over a conventional kraft process are substantial as the heat/energy requirement for the latter is not only a great source of pollution, but is in large part the reason the resulting pulp product is so expensive and has high initial capital requirements. The energy savings in the implementation of a process according to a preferred embodiment of the present invention would be reflected in a lower priced pulp, and environmental benefits which would have both an immediate impact and a long-lasting multi-generational benefit for all.
[0076] Further cost savings in the full or partial implementation of a process according to a preferred embodiment of the present invention, can be found in the absence or minimization of restrictive regulations for the operation of a high temperature and high-pressure pulp digestors.
6. EXAMPLES
[0077] The composition according to a preferred embodiment of the present invention used in the delignification test was prepared by dissolving 1 molar equivalent of taurine into sulfuric acid and subsequently adding hydrogen peroxide. The final composition comprised sulfuric acid:taurine:hydrogen peroxide in a 5.0: 1.7: 1.0 molar ratio. Preferably, the resulting pH of the composition is less than 1. More preferably, the resulting pH of the composition is less than 0.5.
[0078] According to a preferred embodiment of the present invention, the composition provides a peroxide yield of above 25% after 7 days of mixing such composition. More preferably, the peroxide percent yield is above 35% after 2 weeks upon mixing said composition.
6.1. Delignification Experiment
[0079] A preferred embodiment of the composition according to the present invention was tested to determine its power in the delignification of a wood chip.
[0080] The experiments were completed using approximately 0.2 g of wood and approximately 20 g of solution. The mixtures were stirred at 200 rpm at a temperature of 30° C.
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[0083] The above experiment is a clear indication that the composition according to the present invention not only provides an adequate dissolving acid to delignify plant material but is also valuable in controlling the ultimate degradation of cellulosic material into carbon black residue resulting in potentially higher yields for the operators, thus increasing profitability while reducing emissions and risks to employees, contractors and the public.
[0084] A method to yield glucose from wood pulp would represent a significant advancement to the current process where the conversion of such is chemically, energy, and emissions intensive; costly; and dangerous while not yielding highly efficient results, especially in large-scale operations. It is desirable to employ a composition which can delignify woody pulp, but also allows the operator some control in order to preserve the cellulose, rather than degrading it to carbon black, in order to improve efficiency and yields, increase safety, and reduce overall costs.
[0085] According to a preferred embodiment of the method of the present invention, the separation of lignin can be achieved and the resulting cellulose fibers can be further processed to yield glucose monomers. Glucose chemistry has a multitude of uses including as a starting block in the preparation of widely used chemicals including, but not limited to, diacetonide, dithioacetal, ethanol, glucoside, glucal and hydroxyglucal to name but a few.
6.2. Additional Delignification Experiments
[0086] Sulfuric acid, taurine and hydrogen peroxide were mixed with decreasing taurine concentrations and reacted with biomass (wood chips) overnight at ambient conditions to assess the effectiveness of the variation on the molar ratios on the extent of reaction. Control tests were run for the respective mixtures with just kraft lignin or just cellulose added instead of biomass. Commercially available lignin (Sigma-Aldrich; Lignin, kraft; Prod# 471003) was used as a control in the testing. Commercially cellulose (Sigma-Aldrich; Cellulose, fibers (medium); Prod# C6288) was also used as a control in the testing.
[0087] The solid phase of each blend was filtered off after 20 h reaction time, rinsed with water and dried in an oven at 45° C. to constant weight. All data given as the average of triplicate runs. An effective blend should dissolve all lignin and leave the cellulose as intact as possible. The results of the experiments are reported in Table 1 below.
TABLE-US-00001 TABLE 1 Recovery of solids (% of initial mass) after 20 h reaction time Wood Lignin control Cellulose control (wt % remaining (wt % remaining (wt % remaining Blend after reaction) after reaction) after reaction) 3:1:3 41.71 0.00 86.15 10:1:10 38.64 0.00 84.67 15:1:15 39.79 0.00 86.81
[0088] A blend with a molar ratio of 3:1:3 of sulfuric acid (96% conc. used) to taurine to hydrogen peroxide (as 30% solution) results in a mass recovery of 40% from wood and 86% from cellulose and none of the lignin. All lignin was broken down enough to get dissolved into the blend. It was noted that reducing the taurine concentration to a 10:1:10 or 15:1:15 does not significantly change the results for solids recovery. Even at the lowest concentration taurine is an effective retardant for the sulfuric acid to stabilize the reaction mixture.
6.3. Skin Corrosiveness Testing
[0089] To assess the immediate corrosiveness of a composition according to a preferred embodiment of the present invention, a visual comparative assessment was carried out using chicken skin. Two chicken skin samples were secured over the opening of two beakers. The first skin sample was exposed to a solution of sulfuric acid (H.sub.2SO.sub.4) and hydrogen peroxide (H.sub.2O.sub.2). The second skin sample was exposed to a composition according to a preferred embodiment of the present invention, namely sulfuric acid; taurine; and hydrogen peroxide (H.sub.2O.sub.2) (in a 5.0:1.7:1.0 molar ratio).
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[0091] The conventional Caro's acid leads to a breakthrough after ca. 5.5 min. The modified Caro's Acid according to the preferred embodiment described and tested breaks through the skin sample after approximately 45 minutes, but the degree of breakthrough is much smaller compared to the conventional Caro's acid. Despite the fact that this is not an OECD recognized official test, this test clearly highlights the advantages that a person, accidentally exposed to the modified Caro's acid according to an embodiment of the present invention, has significantly more time available to find a safety shower to minimize irreversible skin damage and further injuries.
6.4. Titration of Caro's Acid and a Preferred Composition of the Present Invention
[0092] The inventors have titrated both Caro's acid (5.57:1 molar ratio of H.sub.2SO.sub.4: H.sub.2O.sub.2) and a modified Caro's acid (5.0:1.7:1.0 molar ratio of H.sub.2SO.sub.4: Taurine: H.sub.2O.sub.2) both of which were synthesized using an ice bath and constant stirring. The compositions are stored capped, but not sealed in a water bath at a constant temperature of 30° C.
[0093] To determine the concentration of H.sub.2O.sub.2, the solutions were titrated against a standardized KMnO.sub.4 solution. The titration procedure follows: [0094] 1. A solution with approximately 245 mL of dH.sub.2O and 5 mL of 96% H.sub.2SO.sub.4 is prepared [0095] 2. Approximately 1 g of Caro's acid/modified Caro's acid is measured by an analytical balance and recorded [0096] 3. The diluted H.sub.2SO.sub.4 solution is used to quantitatively transfer the measured Caro's acid/modified Caro's acid into a 300 mL Erlenmeyer flask [0097] 4. The solution is mixed constantly with a magnetic stir plate/stir bar during the titration [0098] 5. The solution is titrated using the standardized KMnO.sub.4 solution until the appearance of a persistent pink color for at least 1 minute.
[0099] The moles of H.sub.2O.sub.2 found in the titrated sample and the moles of H.sub.2O.sub.2 used in the synthesis are used to calculate the percent yield.
TABLE-US-00002 TABLE 2 Titration results of Caro's Acid and a preferred composition of the present invention Caro's acid Modified Caro's acid Percent yield of H.sub.2O.sub.2 Percent yield of H.sub.2O.sub.2 as synthesised 16.2 38.9 2 days 18.1 40.0 5 days 16.6 47.9 7 days 15.5 54.9 12 days 7.7 52.7 27 days 0.0 42.6
[0100] The comparison between Caro's acid and the modified Caro's acid show that the modified Caro's acid has significantly more active H.sub.2O.sub.2 after the synthesis, and retains the activity for an extended period of time (at least 27 days); resulting in a product that has a significantly longer shelf life, increasing operational efficiency and minimizing the waste resulting from expired product.
6.5. Batch Process
[0101] Blend used: H.sub.2SO.sub.4: H.sub.2O.sub.2: sulfamic acid in a molar ratio of 10:10:1.
[0102] A batch process was carried out in order to scale up the use of a composition according to a preferred embodiment of the present invention in a process as discussed previously. For the preparation of a batch process, 3,301 g sulfuric acid (93%) was placed in a large glass reactor (10 L nominal volume) and 304 g sulfamic acid was added. The mixture was stirred at 100 RPM with an overhead Teflon paddle stirrer. Then 3,549 g of hydrogen peroxide solution (29%) was slowly added (1-1.5 h) to the modified acid. The reactor was chilled to dissipate the generated heat so that the temperature of the blend does not exceed 40° C. After the hydrogen peroxide addition 846 g of water was added to the mixture and the blend left to equilibrate to ambient temperature (about 30 minutes). The molar blend ratio (in order of addition) was 10:1:10. 400 g of unsized wood shavings (sawdust) was slowly added to the reactor (10 minutes). The temperature rise was monitored. When the reactor temperature reached 50° C., the reactor was chilled to a temperature of 26° C. After this, cooling was no longer necessary. The reaction was carried out for 20 h, then the reaction mixture was transferred to a filter system with a 20 μm Teflon filter sheet. The filtrate was discarded and the remaining filter cake washed with 12 liters of water until the runoff reached a pH value of about 6. The filter cake was the oven dried (45° C.) overnight. The cellulose yield compared to added biomass was 42.6%.
[0103] The hydrocarbon content of the resulting cellulose was determined to be 94.9% which is close to the Sigma-Aldrich cellulose lot# WXBC9745V-95.7% standard used as a comparison. The water content was determined to be 2.22% which is close to the Sigma-Aldrich cellulose lot# WXBC9745V-3% standard used as a comparison. The Kappa#=0, which means that there is no lignin left in the sample. X-ray diffraction was carried out on the sample and indicated that apparent crystallinity was of 58.2% which is in line with our previously tested numbers and the commercial cellulose from Aldrich was measured to be 62.9%. Scanning electron microscopy was carried out shows a material very high fiber content, higher than the Sigma-Aldrich product.
[0104] According to another preferred embodiment of the present invention, the composition can be used to decompose organic material by oxidation such as those used in water treatment, water purification and/or water desalination. An example of this is the removal (i.e. destruction) of algae on filtration membranes. As such membranes can be quite expensive, it is imperative that they be used for as long as possible. However, given the difficulty to remove organic matter which accumulates on it over time, new approaches are necessary to do so efficiently and with as little damage to the membrane as possible. Mineral acids are too strong and, while they will remove the organic matter, will damage the filtration membranes. A preferred composition of the present invention remedies this issue as it is less aggressive than the mineral acids and, as such, will remove the organic contaminants in a much milder approach, therefore sparing the membrane.
[0105] While the foregoing invention has been described in some detail for purposes of clarity and understanding, it will be appreciated by those skilled in the relevant arts, once they have been made familiar with this disclosure that various changes in form and detail can be made without departing from the true scope of the invention in the appended claims.