Cationic arabinoxylans, their hydrophobically modified products, and preparation method and application thereof
The present invention provides a cationic arabinoxylan and the hydrophobically modified product thereof. The cationic arabinoxylan is prepared based on a cereal arabinoxylan and a quaternizing agent, with water as solvent and strong alkali as catalyst. The hydrophobically modified product is prepared based on cationic arabinoxylan and alkyl halide, with pyridine as catalyst. Said cationic arabinoxylan and the hydrophobically modified product thereof can be used as a conditioning agent or thickener in cosmetics or personal care compositions, and can also be used in textile, papermaking, pharmaceutical and food industry applications.
1. A method for preparation of a cationic arabinoxylan, comprising the steps of:
(1) dissolving an arabinoxylan and 0.5-4.0 wt %, of a strong alkali into water wherein the amount of strong alkali is based on the total weight of the strong alkali, arabinoxylan, and water;
(2) adding a quaternizing agent with the molar ratio of the quaternizing agent and anhydroxylose unit of the arabinoxylan being from 0.2:1 to 5:1, and reacting for 2-8 h; and
(3) separating the cationic arabinoxylan as reaction product
wherein the arabinoxylan is selected from water soluble arabinoxylans extracted from the group consisting of corn bran, wheat bran, corn endosperm, wheat endosperm, barley endosperm, rye endosperm, triticale endosperm and oat endosperm.
2. The method of claim 1 , wherein the arabinoxylan has a weight average molecular weight of ≥100,000 g/mol.
3. The method of claim 1 , wherein the molar ratio of Araf residues to Xylp residues of the arabinoxylan is 0.4˜1.2, 0.5˜1.0, 0.5˜0.95, 0.5˜0.93, 0.6˜1.0, 0.6˜0.95, 0.6˜0.93, 0.7˜1.0, 0.7˜0.95, or 0.7˜0.93.
4. The method of claim 1 , wherein the degree of substitution of cationic group of the cationic arabinoxylan is 0.03˜1.0, 0.03˜0.8, 0.04˜0.8, 0.04˜0.7, 0.04˜0.6, 0.06˜0.6, 0.08˜0.6, or 03˜0.6.
5. The method of claim 1 wherein:
(1) dissolving an arabinoxylan and 2.1:1-2.8 wt % of a strong alkali into water wherein the amount of strong alkali is based on the total weight of the strong alkali, arabinoxylan, and water;
(2) adding a quaternizing agent with the molar ratio of the quaternizing agent and anhydroxylose unit of the arabinoxylan being from 2:1 to 4:1, and reacting for 4-7 h, at 20-35° C.
6. The method of claim 1 , wherein the weight average molecular weight of the cationic arabinoxylan is ≥100,000 g/mol.
7. The method of claim 1 , wherein the molar ratio of Araf residues to Xylp residues of the arabinoxylan is 0.5˜1.0.
8. The method of claim 1 , wherein the degree of substitution of cationic group of the cationic arabinoxylan is 0.04˜0.8.