NL1004738C2 - Fructan polycarboxylic acid. - Google Patents

Description

Fructan polycarboxylic acid

The invention relates to fructan polycarboxylic acids.

WO 91/17189 discloses fructan polycarboxylic acids in the form of polycarboxy inulin, also referred to as dicarboxyinulin (DCI). In DCI, the C3-C4 bond 5 of the oxidized anhydrofructose unit is broken to form units of the formula: [HOCH2-CH (C00H) -O-C (C00H) -CH2-0] n. DCI is obtained according to WO 91/17189 by oxidation of inulinc with a hypohalite. DCI with a degree of substitution (DS: number of carboxyl groups per monosaccharide unit) on the order of 1-2 has a good calcium binding capacity.

According to WO 94/21690, DCI can be prepared by oxidation of inulin with hydrogen peroxide in the presence of a halide salt and / or a transition metal salt. According to Starch / Starke 41, 348 (1989), DCI can be prepared by periodate treatment followed by chlorite treatment.

WO 95/07303 discloses a process for the oxidation of inulin, in which the primary hydroxyl group is mainly oxidized to a carboxyl group with hypohalogenite in the presence of a di-tert-alkyl nitroxyl such as TEMPO (tetramethylpiperidine-1-oxyl).

Carboxymethylinulinc with a DS of 0.15-2.5 is known from WO 95/15984 and from the article by Verraest et al in JAOCS, 73 (1996) pp. 55-62. It is prepared by reacting a concentrated solution of inulin with sodium chloroacetate at an elevated temperature. Carboxymethylinulinc (CMI) has beneficial properties as an inhibitor of crystallization of calcium carbonate.

It has now been found that a fructan polycarboxylic acid, which contains both oxidation-derived carboxyl groups, the carbon of which is part of the anhydrofructose units, as well as carboxymethyl groups, has improved properties in calcium binding capacity, calcium carbonate dispersing capacity and crystal growth inhibiting capacity, which improvements go beyond what would be expected from a combination of dicarboxy inulin and carboxymethylinulinc.

The fructan polycarboxylic acid of the invention, or salt thereof, has a degree of substitution for oxidation-derived carboxyl groups of at least 0.05 per original anhydrofructose unit and a degree of substitution for carboxymethyl groups of at least 1 00 A 7 38 0.1 per anhydrofructose unit. The carboxyl groups obtained by oxidation can be obtained by oxidation of the vicinal hydroxy-methylene groups at positions 3 and 4 of the hydrofructose unit and / or by oxidation of the hydroxymethyl group at position 6. The carboxymethyl groups can be obtained by carboxymethylation of one of the three hydroxyl groups of the anhydrofructose unit. In other words, of the fructan polycarboxylic acid, at least 0.05 (by oxidation) is converted into a carboxyl group per 3 hydroxymethyl (one) groups of the fructan and at least 0.1 (through carboxymethylation) is converted into a carboxymethoxyl group per 3 hydroxyl groups. . Preferably, the number of hydroxymethyl (one) groups converted to a carboxyl group is at least 0.2 and in particular at least 0.3 per 3, increasing to a maximum of 3, in particular a maximum of 2 per 3. Preferably the number of hydroxyl groups converted to carboxymethoxy groups is at least 0.3, in particular at least 0.5, increasing to 2, in particular to 1.6. Preferably, the total degree of substitution (DS) of carboxyl groups is 0.8-3.0, in particular 1.0-2.5. It is further preferred that hydroxymethyl (ecn) groups converted to carboxyl groups and hydroxyl groups converted to carboxymethoxy groups are in the same molecule.

Here, fructans are understood to mean all oligo- and polysaccharides that have a majority of anhydrofructose components. Dc fructans can have a polydisperse chain length distribution and can be branched or branched. Preferably, the fructan mainly contains β-2,1 ^^ ίι ^ εη as in inulin. The fructans include products obtained directly from vegetable or other sources, as well as products in which the mean chain length has been changed (increased or decreased) by fractionation, enzymatic synthesis or hydrolysis. The fructans have an average chain length (= 25 degree of polymerization, DP) of at least 3, rising to about 60. Preferably, the average chain length is at least 6, in particular at least 10, monosaccharide units. In particular, it is fructan inulin (β-2,1-fructan) or a modified inulin. Inulin can be obtained from, for example, chicory, dahlia and Jerusalem artichoke, or genetically modified crops such as sugar beet.

Fructans which can serve as the basis for the fructan polycarboxylic acids according to the invention are, in addition to the natural and industrial base polysaccharides, for example, hydrolysates, ie short chain fructan derivatives, and fractionated products of modified chain length, in particular with an average chain length of at least 1004738 3 10. Fractionation of fructans such as inulinc can be accomplished by, for example, cool crystallization (see WO 96/01849), column chromatography, or membrane filtration (see EP-A-440074 and EP-A-627490) or selective precipitation with an alcohol. Other fructans, such as short-chain fructans obtained, for example, by crystallization, fructans from which mono- and disaccharides have been removed and fructans whose chain length has been enzymatically extended, can also be converted into fructan polycarboxylic acids. Reduced fructans are also eligible. Reduced fructans are fructans whose reducing terminal groups (usually fructose groups) have been reduced, for example, with sodium borohydride or with hydrogen in the presence of a transition metal catalyst.

The fructan polycarbonates according to the invention can be prepared by oxidation of the fructan in a manner known per se, followed by carboxymethylation in a manner known per se, or by the reverse sequence of operations. For example, the carboxymethylation can be carried out with aqueous sodium monochloro-15 acetate at pH 10-13, or with another halo-acetic acid derivative. The oxidation can be carried out in various ways, for example with hypohalogenict, with periodate / chlorite or with hydrogen peroxide, each of which mainly leads to dicarboxygrocpcn (C3-C4-cleavage) or with hvpochlorite / TEMPO, which leads to monocarboxy groups (C6- oxidation), as described in the aforementioned publications.

Preferably, if the fructan is first carboxymethylated, a DS of no more than 1.2 is achieved, leaving sufficient sites for the subsequent C3-C4 oxidation. In case of subsequent C6 oxidation, the carboxymethylation can also be continued, for example up to a DS of 2.0. It is preferred to first oxidize the fructan to a DS of at least 0.2, for example to a DS of 0.5-1.0 (25-50% oxidation in the case of C3-C4 oxidation). Subsequently, the oxidized product can be carboxymethylated, for example to a DS of 0.5-1.6. Optionally, the solution obtained on oxidation is concentrated to increase the efficiency of the carboxymethylation. It is often advantageous to start from a fructan from which any reducing units 30 have been removed by treatment with a reducing agent such as sodium borohydride or hydrogen in combination with a transition metal catalyst. An advantageous order of treatment is then reduction - oxidation - carboxymethylation - purification.

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The fructan polycarboxylic acids of the invention have an excellent combination of calcium binding, calcium carbonate dispersing and crystal growth inhibiting properties, as illustrated in the examples. These new materials are therefore ideally suited as a multifunctional component of cleaning agents. In addition, these fructan polycarboxylic acids can be used as an auxiliary in water treatment agents, textile treatment agents, in papermaking, in gluing and in the removal of heavy metals from soil, sludge or other sediments.

Examples

General io Determination of calcium binding capacity (CBV):

From standard solutions 10 ~? and 10'5 M Ca 2+ (with 5 * 10 ~ N NaCl), the potential is determined with a calcium-select electrode. To 150 ml of 10-3 M Ca2 + (+ 5 * 10'3 N NaCl) measuring solution, an amount of polycarboxylic acid is added such that the concentration decreases to 10'5 M. If x is the required number of grams of polycarboxylic acid, then: CBV = {1000 * (10 '- 10'5)} / (1000 * x / 150) in mmol Ca per g polycarboxylic acid.

Calcium carbonate dispersant (CCDV) determination:

An amount of ± 1 g of polycarboxylic acid is carefully weighed and made up to 100.0 g with de-mineralized water. To this is added 10.0 ml of 10% w / v Na2CO3 and a spectrophotometric immersion cell is placed in the solution. When the transmission of the solution has a constant value at 700 nm, the stirred solution (300 rpm) is added in increments of 0.25 or 0.50 ml of calcium acetate (0.25 M). The inflection point (the point at which the first cloudiness occurs) is determined from the titration curve. If at the inflection point x ml of Ca acetate has been consumed, then: 25 CCDV = (x * 0.25 * 100.08) / (incorporated polycarboxylic acid in g)

Determination of crystal growth inhibitory capacity (KRV) on calcium carbonate: 100 ml 0.02 M K2CO, 100 ml 0.02 M CaCl2 and 2.0 ml 1000 ppm polycarboxylic acid are combined. The polycarboxylic acid concentration is 10 ppm. The solution is stirred with a microwave (800 rpm) for a minimum of 60 minutes at a constant temperature of 20 ° C. The particle size in the solution is determined with a Malvcm-1004738 5 particle size meter (twice per solution; two solutions, so 4 measurements). The average particle size Dr is compared with the average particle size D0 of a solution without polycarboxylic acid. KRV = D (/ Dr

Determination of the carboxyl content: 5 The carboxyl content is determined on the basis of the sodium content of the purified end product.

Example 1

Preparation of carboxymethylated DCI:

210.0 g inulinc (standard, chicory, avg. DP 10, composition see 10 table 3, dry matter content 95 wt.%, 1.2 mol) was dissolved in 667 ml water containing 0.02 M NaBr . To this was added 800.8 g sodium hypochlorite (1.85 mmol NaOCl / g: 1.48 mol = 0.41 eq.) Over 2 hours at room temperature. After 24 hours of reaction at <25 ° C and pH 10.5 (pH-stat, 4.0 N NaOH), the caustic consumption was 1040 mmol and no hypochlorite was detected anymore. The solution was purified using the Pl-electrodialve Aqualizcr from E.I.V.S. Corning (30V, 20-60 min, electrolyte and salt compartment 1% NaCl). The purified solution was evaporated to dryness and dried in a vacuum oven at 70 ° C. Yield 240.3 g; DSCOOH = 0.66 (degree of oxidation: 33%; yield relative to hypochlorite: 81%).

To a solution of 40 g (215 mmol) of the DCI thus obtained in 133 ml of water (= 30% w / v), sodium monochloroacetate (NaMCA) (16.3 g, 14 mmol) and sodium hydroxide (6.1 = 150 mmol) as dry matter (dry matter content reaction mixture: 39% by weight). After 4 hours at 60 ° C, the pH was lowered to 10 with HCl. The degree of carboxymethyl substitution was determined on the crude product from the difference between the amount of MCA added and the amount of MCA recovered, glycolic acid and oxydiacetic acid (digcolic acid). Result 66.8 mmol of carboxymethyl product: DSch2cooh = 0.32. DSlotaiJ = 0.98.

The carboxymethylation was repeated, but then with 35.8 g (= 0.31 mol) and 58.4 g (= 0.50 mol) NaMCA (dry substance mixture, 53 wt% and 67 wt%, respectively). The DSCH2COOH obtained is resp. 0.79 and 1.14.

The carboxymethylated DCI was purified in the same manner as DCI (concentration in water: 15% w / v). Yield 270.3 g; DScoo = 0.98. The other carboxy-1004738 6 methylations gave yields of resp. 319.5 and 353.1 g. The physical data are given in Tables 1 and 2 (Nos 1, 2 and 3).

Table 1: Properties of oxidized and / or carboxymethylated standard inulin DS CBV (1) CCDV (2) KRV (3) ____ wt. <% Mmol Ca / g mg CaCO ^ / g No. DCI-CMI-COOH COOH (mmol Ca (mg CaCO3 D (/ D, COOH COOH total / g COOH) / g COOH) __ carboxymethylated DCI __ 5 1 0.66 0.32 0.98 19.3 1.1 (5.7) 93 (481) 1 .5 2 0.66 0.79 1.45 23.5 1.4 (6.0) 118 (501) 3.3 3 0.66__U4 1.80 26.4 1.5 (5.7) 125 ( 473) 2.9 oxidized CMI__________ 11 0.64 0.30 0.94 16.6 0.6 (3.6) 67 (403) 1.2 12 0.64 0.83 1.47 23.0 0, 9 (3.9) 96 (418) 1.4 10 13 0.64__U4__1.78 25.8 1.3 (5.0) 91 (352) 1.8 mixture DCI + CMI ^ _________ 21 0.62 0, 38 1.00 21.8 0.6 (2.8) 60 (275) 1.3 22 0.48 0.95 1.43 28.1 1.0 (3.6) 69 (245) 2.5 23 0.51__U3__1.64 27.4 1.1 (4.0) 81 (296) 2.5 __DCI______ 31 0.66 - 0.66 21.0 0.8 (3.8) 88 (418) 1, 2 15 32 1.14 - 1.14 25.1 1.1 (4.4) 114 (455) <1 33 1.72 - 1.72 34.1 1.5 (4.4) 130 (382) __1.3 ___CMI________ 41 - 1.14 1.14 20.7 0.6 (2.0) 25 (121) 2.0 42 - 1.53 1.53 25.6 0.8 (3.1) 44 (172) 2.9 43 - 2.00 2.00 27.0 1.3 (4 , 8) 56 (208) 2.9 20 (1) Calcium Binding Power in mmol Ca per g product (and per g carboxyl) (2) Calcium Carbonate Dispersing Power in mg CaCO3 per g product (and per g carboxyl) (3) Crystal growth Inhibitory Power: ratio between CaCO3 blank particle size and particle size at 10 ppm product.

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Table 2: Properties of carboxymethylated oxidized inulin

DS CBV CCDV KRV

carboxymethylated DCI wt% mmol Ca / g mg CaCOj / g no DCI-CMI-COOH C0 ° H (mmol Ca (mg CaCO3 Dq / D, COOH COOH total / g COOH) / g COOH) standard inulin (avg. DP = 10) 1 0.66 0.32 0.98 19.3 1.1 (5.7) 93 (481) 1.5 2 0.66 0.79 1.45 23.5 1.4 (6, 0) 118 (501) 3.3 5 3 0.66 1.14 1.80 26.4 1.5 (5.7) 125 (473) 2.9 Precipitation cool crystallization (average DP = 30) 101 0, 60 0.48 1.08 21.2 1.1 (5.2) 94 (110) 0.9 102 0.60 0.97 1.57 25.6 1.3 (5.1) 106 (414) 1.4 103 0.60 1.20 1.80 26.2 1.5 (5.7) 119 (454) 1.8 filtrate cool crystal. + nanofiltr. (mean DP = 10) 201 0.62 0.43 1.05 20.9 0.8 (3.8) 81 (388) 1.7 10 202 0.62 1.04 1.66 26.4 1 2 (4.5) 88 (333) 2.5 203 0.62 1.28 1.90 28.5 1.3 (4.6) 99 (347) 2.5

Table 3: Composition of different types of inulin composition standard inulin precipitation filtrate cooling crystal.

(%) cooling crystal. after nanofiltration 15 glucose 0.5 0.05 0.2 fructose 2.3 0.1 1.0 disaccharides 4.3 0.05 1.6 trisaccharides 2.8 0.05 --- 5.7 tetrasaccharides 3.5 0.05 ____ (DP 3-4) 20 pentasaccharides 6.1 0.2 --- 91.2 DP> 5 76.1 99.5 ____ (DPaS) mean DP 10 30 10 1004738

Claims (13)

A fructan polycarboxylic acid or salt thereof, in which at least 0.05 per 3 hydroxymethyl (one) groups of the fructan is converted into a carboxyl group and at least 0.1 per 3 hydroxyl groups is converted into a carboxymethoxy group. 2. Fructan polycarboxylic acid or salt thereof, in which per 2 hydroxymethyl (one) groups of the fructan 0.2-2.0 are converted into a carboxyl group and per 3 hydroxyl groups 0.3-2.0 is converted into a carboxymethoxy group. converted. A fructan polycarboxylic acid according to claim 1 or 2, wherein the hydroxymethyl (ecn) groups converted into carboxyl groups and the hydroxyl groups converted into carboxymethyl groups are in the same molecule. Fructan polycarboxylic acid according to any one of claims 1-3, wherein the total degree of substitution (DS) of carboxyl groups is 0.15-3.0. Fructan polycarboxylic acid according to any one of claims 1-4, wherein the fructan is inulin. 6. Process for preparing a fructan polycarboxylic acid, wherein a fructan is oxidized and the oxidation product is then carboxymethylated. 7. A process for preparing a fructan polycarboxylic acid, wherein a fructan carboxymethylate and the ractic product is subsequently oxidized. 8. Process according to claim 7, wherein the carboxymethylation is carried out to a substitution degree of 0.1-2.0. Process according to any one of claims 6-8, wherein the oxidation is carried out with a hypohalite. The process according to claim 9, wherein the oxidation is carried out in the presence of a di-tert-alkyl-nitroxyl. A process according to any one of claims 6-10, wherein the fructan is reduced prior to the oxidation and carboxymethylation. 1004738 Crystal growth inhibitory, calcium binding and / or dispersant containing a fructan polycarboxylic acid according to any one of claims 1 to 5. 13. Use of a fructan polycarboxylic acid according to any one of claims 1-5 in water treatment agents, cleaning agents, textile treatment agents, in papermaking, in gluing and in the removal of heavy metals. 1004738