Solvent-free methods of synthesizing chloroacetylated-alpha-1,3-glucans and compositions

Abstract

Methods of chloroacetylation, such as methods of preparing chloroacetylated-α-1,3-glucan in solvent-less synthesis conditions. The methods may include contacting α-1,3-glucan, chloroacetic acid, and optionally a quaternary ammonium salt to produce a chloroacetylated-α-1,3-glucan. The contacting of the α-1,3-glucan, the chloroacetic acid, and optionally the quaternary ammonium salt may not occur in the presence of an organic solvent.

Description

SOLVENT-FREE METHODS OF SYNTHESIZING CHLOROACETYLATED-ALPHA-1,3-GLUCANS AND COMPOSITIONSCross-reference to Related Applications

[0001] This application claims priority to Finnish Patent Application No. 20246440, filed December 10, 2024, and U. S. Provisional Patent Application No. 63 / 713,424, filed October 29, 2024, which are incorporated by reference herein.Background

[0002] Chloroacetylated polysaccharides are viewed as likely promising raw materials for the preparation of a number of materials, such as cationic polysaccharides and other functionalized bio-based materials.

[0003] The known and widely-used methods for producing chloroacetylated polysaccharides, however, typically use organic solvents, which can be disadvantageous for one or more reasons. The organic solvents, for example, usually are expensive, are toxic, require time-consuming or laborious purification steps to isolate a reaction product, or a combination thereof.

[0004] There remains a need for improved methods for preparing chloroacetylated polysaccharides, such as chloroacetylated-a-l,3-glucan. including methods that do not rely on organic solvents.Brief Summary

[0005] Provided herein are methods of preparing chloroacetylated-a-l,3-glucan in solvent-less synthesis conditions.

[0006] In one aspect, methods of chloroacetylation are provided. In some embodiments, the methods include contacting a-l,3-glucan, chloroacetic acid, and a quaternary ammonium salt to produce a chloroacetylated-a-l,3-glucan. The contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt, in some embodiments, does not occur in the presence of an organic solvent, as described herein. The quaternary ammonium salt may include choline chloride. In some embodiments, the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt occurs in the presence of an acid other than the chloroacetic acid, such as any suitable acidic catalyst. Suitable acidic catalysts may include a sulfonic acid, such as p-toluene sulfonic acid.

[0007] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the aspects described herein. The advantages described herein may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.Detailed Description

[0008] Provided herein are methods of chloroacetylation, which may be used to produce chloroacetylated-a-l,3-glucan having any desired degree of substitution.

[0009] In some embodiments, the methods include contacting α-1,3-glucan, chloroacetic acid, and a quaternary ammonium salt to produce a chloroacetylated-a-1,3-glucan. In some embodiments, the contacting of the a-l,3-glucan and the chloroacetic acid does not occur in the presence of a solvent, such as an organic solvent. A ‘"contacting” limitation described herein "does not occur in the presence of a solvent” when a solvent is present at an amount of less than 5 wt%, less than 2 wt%, less than 1 wt%, less than 0.1 wt%, or less than 0.01 wt%, based on the weight of the a-l,3-glucan.

[0010] The contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt may be achieved using any known technique and any known apparatuses. The starting materials also may be contacted in any order or in any manner. In some embodiments, the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt includes providing a mixture that includes the chloroacetic acid, the quaternary ammonium salt, and optionally one or more non-solvent additives, such as an acid other than the chloroacetic acid (e.g., a suitable acidic catalyst, such as a sulfonic acid); and disposing the a-l,3-glucan in the mixture to form a reaction mixture that includes the chloroacetylated-a-1,3-glucan.

[0011] The mixture may be processed in any manner. For example, the methods may include heating the mixture prior to the disposing of the a-l,3-glucan in the mixture, such as to a temperature of about 80 °C to about 120 °C, or about 100 °C, optionally for a time of about 0.1 hours to about 2 hours, about 0.1 hours to about 1 hour, or about 0.5 hours. The mixture then may be cooled, actively or passively, prior to the disposing of the a-l,3-glucan in the mixture, such as to a temperature of less than 80 °C, such as about 60 °C to about 75 °C. The methods also may include drying (e.g., vacuum drying) the mixture prior to the disposing of the a-l,3-glucan in the mixture.

[0012] The reaction mixture may be processed in any manner. In some embodiments, the methods include heating the reaction mixture, such as to a temperature of about 70 °C to about 90 °C, optionally under reduced pressure, such as about 1 mbar to about 150 mbar, or about 30 mbar to about 150 mbar, optionally for a time period of about 12 hours to about 36 hours, or about 18 hours to about 24 hours, and optionally without stirring.

[0013] The methods also may include isolating one or more components, such as the chloroacetylated-α-1,3-glucan. from the reaction mixture. The isolating of the one or more components may be achieved using any known apparatus and technique, such as those described herein. In some embodiments, the methods include drying the chloroacetylated-α-1,3-glucan. The drying may occur at a temperature greater than room temperature (e.g., about 90 °C to about 95 °C) and / or a reduced pressure (e.g., about 8 μbar to about 20 μbar).

[0014] Generally, a-l,3-glucan may be contacted with any amount of chloroacetic acid. For example, a-l,3-glucan may be contacted with a molar excess of chloroacetic acid. The amount of chloroacetic acid, such as the molar excess of chloroacetic acid, may be selected to achieve, at least in part, a desired degree of substitution of the a-l,3-glucan. In some embodiments, a mole ratio of the a-1,3-glucan to the chloroacetic acid is about 1: 1 to about 1:5, about 1:1 to about 1:4, about 1:1 to about 1:3, about 1:1 to about 1:2.5, about 1:1 to about 1:2, about 1: 1 to about 1: 1.5, or about 1: 1 to about 1:1.1. When “a mole ratio’' is defined herein, the mole ratio defines, by mole, the relative amounts of the indicated reagents that are contacted.

[0015] A chloroacetylated-a-1,3-glucan may have any degree of substitution (DS), e.g., 0 < DS < 3. The phrase “degree of substitution”, as used herein, refers to the degree of chloroacetylation, or, in other words, the number of chloroacetyl groups per cyclic moiety of the a-l,3-glucan. as determined by13C NMR. In some embodiments, the degree of substitution of the chloroacetylated-a-1, 3-glucan is about 0.2 to about 1, about 0.3 to about 1, or about 0.3 to about 0.8, but other values are envisioned, and may be selected in view of an intended use of the chloroacetylated product.

[0016] Generally, any quaternary’ ammonium salt may be used in the methods described herein. The quaternary ammonium salt generally may include any counterion, such as an inorganic anion. In some embodiments, the quaternary ammonium salt includes a halide counterion, such as a chloride. In some embodiments, the quaternary’ ammonium salt is a compound of the following formula:

[0017] wherein R1, R2, and R3are independently selected from a C1-C4 hydrocarbyl, such as a monovalent C1-C4 alkyl; R4is a divalent C1-C5 hydrocarbyl, such as a C1-C5 alkylene; and X is a halide. In some embodiments, R1, R2, R3are methyl; and R4is ethylene. In some embodiments, R1, R2, R3are methyl; R4is ethylene; and X is chloride. In some embodiments, the quaternary ammonium salt includes choline chloride.

[0018] Generally, a-l,3-glucan may be contacted with any amount of a quaternary ammonium salt. In some embodiments, a mole ratio of the a- 1,3-glucan to the quaternary ammonium salt is about 10:1 to about 2:1, about 9:1 to about 2:1, about 8:1 to about 2:1, about 7:1 to about 2:1, about 6:1 to about 2:1, about 5:1 to about 2:1 about 4:1 to about 2:1, or about 4: 1 to about 3:1.

[0019] The contacting of a-l,3-glucan and chloroacetic acid may occur in the presence of one or more non-sol vent additives. In some embodiments, the contacting of the a-l,3-glucan and the chloroacetic acid occurs in the presence of an acid other than chloroacetic acid, such as any suitable acidic catalyst. The acid other than chloroacetic acid may be a sulfonic acid. The sulfonic acid may be an aryl sulfonic acid, such as ^p-toluene sulfonic acid. The acid other than chloroacetic acid may be present at any amount. In some embodiments, a mole ratio of the a-l,3-glucan to the acid other than chloroacetic acid is about 300:1 to about 50:1, about 200:1 to about 50:1, or about 100:1 to about 50:1.

[0020] The a- 1,3-glucan used as a starting material in the methods described herein may be obtained from any source. The a- 1,3-glucan may be made according to known methods, such as those disclosed in U.S. Patent No. 8,642,757, U.S. Patent No. 9,139,718, U.S. Patent No. 9,169,506, U.S. Patent No. 10,472,657, and U.S. Patent No. 10,774,352. For example, poly a-l,3-glucan can be enzymatically produced from sucrose using one or more glucosyltransferase (gtf) enzymes (e.g., gtfJ), such as those disclosed in U. S. Patent No. 7,000,000, U. S. Patent Application Publication No. 2013 / 0244288 and U. S. Patent Application Publication No. 2013 / 0244287.

[0021] The a-l,3-glucan generally may have any molecular weight. In some embodiments, the a-l,3-glucan has a molecular weight (weight average molecular weight, Mw) of about 500 g / mol to about 200,000 g / mol, about 500 g / mol to about 150,000 g / mol.about 500 g / mol to about 100,000 g / mol, about 500 g / mol to about 75,000 g / mol, about 500 g / mol to about 50,000 g / mol, about 500 g / mol to about 25,000 g / mol, about 500 g / mol to about 15,000 g / mol, about 500 g / mol to about 14,000 g / mol, about 500 g / mol to about 13,000 g / mol, about 500 g / mol to about 12,000 g / mol, about 500 g / mol to about 11,000 g / mol, about 500 g / mol to about 10,000 g / mol, about 500 g / mol to about 9,000 g / mol, about 500 g / mol to about 8,000 g / mol, about 500 g / mol to about 7,000 g / mol, about 500 g / mol to about 6,000 g / mol, about 500 g / mol to about 5,000 g / mol, about 500 g / mol to about 4,000 g / mol, about 500 g / mol to about 3,000 g / mol, about 500 g / mol to about 2,000 g / mol, about 500 g / mol to about 1,500 g / mol, about 500 g / mol to about 1,000 g / mol, or about 500 g / mol to about 800 g / mol.

[0022] In some embodiments, the α-1,3-glucan, prior to the contacting of the a-1,3-glucan, the chloroacetic acid, and the quaternary ammonium salt is not dried. In other words, the a-l,3-glucan is not subjected to a process configured to reduce its water content by at least 50 wt%, at least 75 wt%, or at least 90 wt%. Therefore, the a-l,3-glucan (such as prior to and / or at onset of the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt) may have a water content (due, for example, to adsorption) greater than 5 wt%, 10 wt%, or 15 wt%, such as a water content of about 0.01 wt% to about 15 wt%, about 5 wt% to about 15 wt%, or about 10 wt% to about 15 wt%. Not wishing to be bound by any particular theory, it is believed that a water content of the a-l,3-glucan of at least 5 wt% or at least 10 wt% may be advantageous in some embodiments of the methods described herein for one or more reasons, such as increasing the yield of the chloroacetylated product.

[0023] In some embodiments, the methods include drying the a-l,3-glucan. The drying of the a-l,3-glucan may include any process that reduces the water content of the a-1,3-glucan by at least 50 wt%, at least 75 wt%, or at least 90 wt%. In some embodiments, the drying of the a-l,3-glucan occurs at a temperature greater than room temperature (e.g., about 100 °C to about 140 °C) and / or reduced pressure (e.g., about 5 pbar to about 20 pbar).

[0024] The phrases ‘'Ci-Ct.hydrocarbyl,” "C^-Crhydrocarbyl.” and the like, as used herein, generally refer to aliphatic, aryl, or arylalkyl groups containing 1 to 6 carbon atoms, or 2 to 4 carbon atoms, respectively, which may be monovalent or multivalent, as noted herein, and including any substituted derivatives thereof. Therefore, for example, the alkyl groups noted below may be alkylene groups, the cycloalkyl groups may be cycloalkylene groups, etc.

[0025] Examples of aliphatic groups, in each instance, include, but are not limited to. an alkyl group, a cycloalkyl group, an alkenyl group, a cycloalkenyl group, an alkynyl group, an alkadienyl group, a cyclic group, and the like, and includes all substituted, unsubstituted, branched, and linear analogs or derivatives thereof, in each instance having 1 to about 6 carbon atoms, 2 to 4 carbon atoms, etc, Examples of alkyl groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl, hexyl, isohexyl, etc, Cycloalkyl moieties may be monocyclic or multi cyclic, and examples include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. Additional examples of alkyl moieties have linear, branched and / or cyclic portions (e.g., 1-ethyl-4-methyl-cyclohexyl). Representative alkenyl moieties include vinyl, allyl. 1-butenyl, 2-butenyl. isobutylenyl, 1-pentenyl, 2-pentenyl, 3-methyl-l-butenyl, 2-methyl-2-butenyl, 2,3-dimethyl-2-butenyl, 1 -hexenyl, 2-hexenyl, 3-hexenyl, 1 -heptenyl, 2-heptenyl, 3-heptenyl, 1 -octenyl, 2 -octenyl, 3-octenyl, 1-nonenyl, 2-nonenyl, 3-nonenyl, 1 -decenyl, 2-decenyl and 3-decenyl. Representative alkynyl moieties include acetylenyl, propynyl, 1-butynyl, 2-butynyl, 1 -pentynyl, 2-pentynyl, 3-methyl-l-butynyl, 4-pentynyl, 1 -hexynyl, 2-hexynyl, 5-hexynyl, etc. Examples of aryl or arylalkyl moieties include, but are not limited to, anthracenyl, azulenyl, biphenyl, fluorenyl, indan, indenyl, naphthyl, phenanthrenyl, phenyl, 1,2,3,4-tetrahydro-naphthalene, tolyl, xylyl, mesityl, benzyd, and the like, including any heteroatom substituted derivative thereof.

[0026] Unless otherwise indicated, the term “substituted,"’ when used to describe a chemical structure or moiety, refers to a derivative of that structure or moiety wherein (i) a multi-valent non-carbon atom (e.g., oxygen, nitrogen, sulfur, phosphorus, etc.) is bonded to one or more carbon atoms of the chemical structure or moiety' (e.g., a “substituted” Ca hydrocarbyl may include, but is not limited to, diethyl ether moiety, an ethyl acetate moiety, a methoxylmethyl acetate moiety, a methyl propionate moiety, an N,N-dimethylacetamide moiety, a butoxy moiety, etc., and a "‘substituted” aryl C12 hydrocarbyl may include, but is not limited to, an oxy dibenzene moiety, a benzophenone moiety, etc.) and / or (ii) one or more of its hydrogen atoms (e.g., chlorobenzene may be characterized generally as an ary l Ce hydrocarbyl “substituted” with a chlorine atom) is substituted with a chemical moiety or functional group such as alcohol, alkoxy, alkanoyloxy, alkoxy carbonyl, alkenyl, alkyl (e.g., methyl, ethyl, propyl, t-butyl), alkynyl, alkylcarbonyl oxy (-OC(O)alkyl), amide (-C(O)NH-alkyl- or -alkylNHC(O)alkyl). tertiary amine (such as alkylamino, arylamino, arylalkylamino), aryl, aryloxy, azo, carbamoyl (-NHC(O)O-alkyl- or -OC(O)NH-alkyl), carbamyl (e.g.. CONH2, as well as CONH-alkyl, CONH-aryl. and CONH-arylalkyl). carboxyl, carboxylic acid, cyano, ester, ether (e.g., methoxy, ethoxy), halo, haloalkyl (e.g., -CCl3, -CF3, -C(CF3)3), heteroalkyl, isocyanate, isothiocyanate, nitrile, nitro, oxo, phosphodiester, sulfide, sulfonamido (e.g, SO2NH2), sulfone, sulfonyl (including alkylsulfonyl, arylsulfonyl and arylalkylsulfonyl), sulfoxide, thiol (e.g., sulfhydryl, thioether) or urea (-NHCONH-alkyl-).

[0027] All referenced publications are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0028] While certain aspects of conventional technologies have been discussed to facilitate disclosure of various embodiments, applicants in no way disclaim these technical aspects, and it is contemplated that the present disclosure may encompass one or more of the conventional technical aspects discussed herein.

[0029] The present disclosure may address one or more of the problems and deficiencies of known methods and processes. However, it is contemplated that various embodiments may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the present disclosure should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.

[0030] In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, known to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.

[0031] In the descriptions provided herein, the terms ‘includes,’’ ‘is,” “containing,” “having,” and “comprises” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” When materials or methods are claimed or described in terms of “comprising” various steps or components, the materials or methods can also “consist essentially of’ or “consist of’ the various steps or components, unless stated otherwise.

[0032] The terms “a,” “an,” and “the” are intended to include plural alternatives, e.g., at least one. For instance, the disclosure of “a quaternary ammonium salt”, “an acid”, and the like, is meant to encompass one. or mixtures or combinations of more than one quaternary ammonium salt, acid, and the like, unless otherwise specified.

[0033] Various numerical ranges may be disclosed herein. When Applicant discloses or claims a range of any type, Applicant's intent is to disclose or claim individually each possible number that such a range could reasonably encompass, including end points of the range as well as any sub-ranges and combinations of sub-ranges encompassed therein, unless otherwise specified. Moreover, all numerical end points of ranges disclosed herein are approximate. As a representative example, Applicant discloses, in some embodiments, a degree of substitution is about 0.3 to about 0.8. This range should be interpreted as encompassing about 0.3 and about 0.8, and further encompasses ‘'about” each of 0.4, 0.5, 0.6, and 0.7, including any ranges and sub-ranges between any of these values.

[0034] As used herein, the term “about” means plus or minus 10 % of the numerical value of the number with which it is being used.EXAMPLES

[0035] The present disclosure is further illustrated by the following examples, which are not to be construed in any way as imposing limitations upon the scope thereof. On the contrary, it is to be clearly understood that resort may be had to various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary’ skill in the art without departing from the spirit of the present invention or the scope of the appended claims. Thus, other aspects of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein.Example 1 - Chloroacetylation of a- 1,3-glucan

[0036] In this example, the following general procedure was used, unless noted otherwise.

[0037] In a round bottom reaction flask, a mixture was prepared that included chloroacetic acid, optionally choline chloride (see below), and -toluene sulfonic acid monohydrate. The mixture was heated, while stirring, to 100 °C for 0.5 hours, and then cooled to 75 °C and optionally vacuum dried.

[0038] a- 1,3-glucan was then added to the mixture, while stirring. The resulting reaction mixture was heated to about 70 °C to about 80 °C, under reduced pressure (e g., about 1 mbar to about 150 mbar, or about 30 to about 150 mbar) for about 18 hours to about 24 hours, without stirring.

[0039] After cooling to room temperature, about 5 mL of isopropyl alcohol (z-PrOH) per gram of the reaction mixture was added to the reaction mixture.

[0040] An almost colorless dispersion of the modified a-l,3-glucan was stirred for 2 hours at room temperature, filtered, and washed two additional times under the same conditions.

[0041] The obtained products were dried at about 90 °C to about 95 °C at about 8 μbar to about 20 μbar to constant weight. The yield of the obtained a-l,3-glucan, in many experiments, was almost quantitative.

[0042] One experiment of this example was believed to proceed according to the following scheme:

[0043] Several experiments were performed according to the foregoing general method, but in the absence of choline chloride. When the foregoing synthesis was performed in the absence of choline chloride, the results indicated poor wettability of a-l,3-glucan by a modification reagent, and significant sublimation of the chloroacetic acid, which likely resulted in the dark color of the resulting product. The degrees of substitution and the molecular weights of the products, however, were similar to those produced in the presence of choline chloride.Example 2 - Results of Example 1

[0044] The following results were obtained from the procedures described at Example 1.Table 1 - Results of Experiment 1Table 2 - Results of Experiment 2Table 3 - Results of Experiment 3Table 4 - Results of Experiment 4Table 5 - Results of Experiment 5LISTING OF EMBODIMENTS

[0045] The following is a non-limiting listing of embodiments of the disclosure.

[0046] Embodiment 1. A method of chloroacetylation, the method comprising, consisting essentially of, or consisting of-

[0047] contacting a-l,3-glucan and chloroacetic acid to produce a chloroacetylated-a- 1,3 -glucan.Absence of Solvent

[0048] Embodiment 2. The method of any one of the preceding Embodiments, wherein the contacting of the a-l,3-glucan and the chloroacetic acid does not occur in the presence of a solvent, such as an organic solvent.Ratio of a-l,3-glucan and Chloroacetic Acid Degree of Substitution

[0049] Embodiment 3. The method of any one of the preceding Embodiments, wherein a mole ratio of the a-l,3-glucan to the chloroacetic acid is about 1:1 to about 1:5,about 1:1 to about 1:4, about 1:1 to about 1:3, about 1:1 to about 1:2.5, about 1:1 to about 1:2, about 1:1 to about 1:1.5, or about 1:1 to about 1:1.1.

[0050] Embodiment 4. The method of any one of the preceding Embodiments, wherein a degree of substitution (i.e., degree of chloroacetylation, as determined by13C NMR) of the chloroacetylated-a-l,3-glucan is about 0.2 to about 1, about 0.3 to about 1, or about 0.3 to about 0.8.Quaternary Ammonium Salt

[0051] Embodiment 5. The method of any one of the preceding Embodiments, wherein the contacting of the a-l,3-glucan and the chloroacetic acid occurs in the presence of a quaternary ammonium salt.

[0052] Embodiment 6. The method of Embodiment 5, wherein the quaternary ammonium salt comprises, consists essentially of, or consists of a compound of the following formula:

[0054] wherein R1, R2, and R3are independently selected from a C1-C4 hydrocarbyl, such as a C1-C4 alkyl; R4is a divalent C1-C5 hydrocarbyl, such as a C1-C5 alkylene; and X is any suitable counterion, such as a halide.

[0055] Embodiment 7. The method of Embodiment 5 or 6, wherein the quaternary ammonium salt comprises, consists essentially of, or consists of choline chloride.

[0056] Embodiment 8. The method of any one of the preceding Embodiments, wherein a mole ratio of the a-l,3-glucan to the quaternary ammonium salt is about 10: 1 to about 2:1, about 9:1 to about 2:1, about 8:1 to about 2:1, about 7:1 to about 2:1, about 6:1 to about 2:1, about 5:1 to about 2:1 about 4:1 to about 2:1, or about 4:1 to about 3:1.Optional Acid

[0057] Embodiment 9. The method of any of the preceding Embodiments, wherein the contacting of the a-l,3-glucan and the chloroacetic acid occurs in the presence of an acid other than the chloroacetic acid, such as any suitable acidic catalyst.

[0058] Embodiment 10. The method of Embodiment 9, wherein the acid other than the chloroacetic acid comprises, consists essentially of, or consists of a sulfonic acid.

[0059] Embodiment 11. The method of Embodiment 10, wherein the sulfonic acid comprises, consists essentially of, or consists of an aryl sulfonic acid.

[0060] Embodiment 12. The method of Embodiment 11, wherein the aryl sulfonic acid comprises, consists essentially of, or consists of p-toluene sulfonic acid.

[0061] Embodiment 13 The method of any of the preceding Embodiments, wherein a mole ratio of the a-l,3-glucan to the acid other than the chloroacetic acid is about 300: 1 to about 50: 1, about 200: 1 to about 50: 1, or about 100: 1 to about 50: 1.Characteristics of a-l,3-glucan

[0062] Embodiment 14. The method of any one of the preceding Embodiments, wherein the a-l,3-glucan has a molecular weight (Mw) of about 500 g / mol to about 200,000 g / mol, about 500 g / mol to about 150,000 g / mol. about 500 g / mol to about 100.000 g / mol, about 500 g / mol to about 75,000 g / mol, about 500 g / mol to about 50,000 g / mol, about 500 g / mol to about 25,000 g / mol, about 500 g / mol to about 15,000 g / mol, about 500 g / mol to about 14,000 g / mol, about 500 g / mol to about 13,000 g / mol, about 500 g / mol to about 12,000 g / mol, about 500 g / mol to about 11,000 g / mol, about 500 g / mol to about 10,000 g / mol, about 500 g / mol to about 9,000 g / mol, about 500 g / mol to about 8,000 g / mol, about 500 g / mol to about 7,000 g / mol, about 500 g / mol to about 6,000 g / mol, about 500 g / mol to about 5,000 g / mol, about 500 g / mol to about 4,000 g / mol, about 500 g / mol to about 3,000 g / mol, about 500 g / mol to about 2,000 g / mol, about 500 g / mol to about 1,500 g / mol. about 500 g / mol to about 1,000 g / mol. or about 500 g / mol to about 800 g / mol.

[0063] Embodiment 15. The method of any of the preceding Embodiments, wherein the a-l,3-glucan, prior to the contacting of the a-l,3-glucan and the chloroacetic acid, is not dried.

[0064] Embodiment 16. The method of any of the preceding Embodiments, wherein the a-l,3-glucan, prior to, or at onset of, the contacting of the a-l,3-glucan and the chloroacetic acid, has a water content (due, for example, to adsorption) of about 0.01 wt% to about 15 wt%, about 5 wt% to about 15 wt%, or about 10 wt% to about 15 wt%.Additional Reaction Steps, Conditions, and Yield

[0065] Embodiment 17. The method of any of the preceding Embodiments, wherein the contacting of the a-l,3-glucan and the chloroacetic acid comprises, consists essentially of, or consists of -

[0066] providing a mixture comprising chloroacetic acid, optionally the quaternary ammonium salt, and optionally the acid other than chloroacetic acid; and

[0067] disposing the a-1,3-glucan in the mixture to form a reaction mixture comprising the chloroacetylated-a-1,3-glucan.

[0068] Embodiment 18. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of drying the a-l,3-glucan, wherein, optionally, the drying occurs at a temperature greater than room temperature (e.g., about 100 °C to about 140 °C) and / or reduced pressure (e.g., about 5 μbar to about 20 μbar).

[0069] Embodiment 19. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of isolating one or more components, such as the chloroacetylated-a-l,3-glucan, from the reaction mixture.

[0070] Embodiment 20. The method of Embodiment 19, further comprising drying the chloroacetylated-a-l,3-glucan; wherein the drying optionally occurs at a temperature greater than room temperature (e.g., about 90 °C to about 95 °C) and / or a reduced pressure (e.g., about 8 μbar to about 20 μbar).

[0071] Embodiment 21. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of heating the mixture prior to the disposing of the a-l,3-glucan in the mixture, such as to a temperature of about 80 °C to about 120 °C, or about 100 °C, optionally for a time of about 0.1 hours to about 2 hours, about 0.1 hours to about 1 hour, or about 0.5 hours.

[0072] Embodiment 22. The method of Embodiment 21, further comprising, consisting essentially of. or consisting of cooling the mixture, actively or passively, prior to the disposing of the a-l,3-glucan in the mixture, such as to a temperature of less than 80 °C, such as about 60 °C to about 75 °C.

[0073] Embodiment 23. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of drying (e.g., vacuum drying) the mixture prior to the disposing of the a- 1,3 -glucan in the mixture.

[0074] Embodiment 24. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of heating the reaction mixture, such as to a temperature of about 70 °C to about 90 °C, optionally under reduced pressure, such as about 1 mbar to about 150 mbar. or about 30 mbar to about 150 mbar, optionally for a time period of about 12 hours to about 36 hours, or about 18 hours to about 24 hours, and optionally without stirring.

[0075] Embodiment 25. The method of any of the preceding Embodiments, wherein the chloroacetylated-a-l,3-glucan is biodegradable.

Claims

We claim-1. A method of chloroacetylation, the method comprising:contacting a- 1,3 -glucan, chloroacetic acid, and a quaternary ammonium salt to produce a chloroacetylated-a-l,3-glucan;wherein the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt does not occur in the presence of an organic solvent.

2. The method of claim 1, wherein a mole ratio of the a-l,3-glucan to the chloroacetic acid is about 1:1 to about 1:5.

3. The method of claim 1, wherein a mole ratio of the a-l,3-glucan to the quaternary ammonium salt is about 10:1 to about 2:1.

4. The method of claim 1, wherein a degree of substitution of the chloroacetylated-a- 1,3 -glucan is about 0.2 to about 1.

5. The method of claim 4, wherein the degree of substitution is about 0.3 to about 0.8.

6. The method of claim 1, wherein the quaternary ammonium salt comprises choline chloride.

7. The method of claim 1, wherein the contacting of the a-1.3-glucan, the chloroacetic acid, and the quaternary ammonium salt occurs in the presence of an acid other than the chloroacetic acid.

8. The method of claim 7, wherein the acid other than the chloroacetic acid comprises a sulfonic acid.

9. The method of claim 7, wherein a mole ratio of the a-l,3-glucan to the sulfonic acid is about 300: 1 to about 50: 1.

10. The method of claim 1, wherein the a-l,3-glucan has a molecular weight (Mw) of about 500 g / mol to about 200,000 g / mol.

11. The method of claim 1, wherein the a-1,3-glucan has a molecular weight (Mw) of 500 g / mol to about 2,000 g / mol.

12. The method of claim 1, wherein the a-l,3-glucan is not dried prior to the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt.

13. The method of claim 1, wherein the a-l,3-glucan has a water content of about 0.01 wt% to about 15 wt% at onset of the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt.

14. The method of claim 1, wherein the contacting of the a-l,3-glucan, the chloroacetic acid, and the quaternary ammonium salt comprises:providing a mixture comprising the chloroacetic acid and the quaternary ammonium salt; anddisposing the a-l,3-glucan in the mixture to form a reaction mixture comprising the chloroacetylated-a-l,3-glucan.

15. The method of claim 14, further comprising isolating the chloroacetylated-a- 1,3- glucan from the reaction mixture.

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