A kind of hydrocarbon-based bridged lignin-based polymer and its preparation method and application

Abstract

The invention discloses an alkane-bridged lignin-based polymer, a preparation method and application thereof. The preparation method is to dissolve lignosulfonate in water, add alkali substances, and then add polyhalogenated alkane monomers or polyhalogenated alkane monomers with aromatic rings to the reaction solution, and carry out bridging polymerization to obtain high molecular weight lignin base polymer. The weight-average molecular weight of the prepared lignin-based polymer can reach 10000Da-500000Da, and has relatively low molecular weight dispersion. The raw material cost of the product of the present invention is low, the source is abundant, and the process is easy to operate. It is used in coal-water slurry and titanium dioxide slurry, and its dispersion performance can be greatly improved at a low dosage. It is a new type of lignin with wide application prospects. base polymer.

Description

technical field [0001] The present invention relates to a lignin-based polymer, in particular to an alkane-bridged lignin-based polymer and a preparation method thereof. Application in suspension systems. Background technique [0002] Lignin is a product recovered from the black liquor of alkaline pulping in the paper industry. There are many active groups in its molecular structure, such as aromatic groups, phenolic hydroxyl groups, alcoholic hydroxyl groups, methoxyl groups, carbonyl groups, carboxyl groups, and conjugated double bonds. etc., and various chemical modification reactions can be carried out. A common modification method is to effectively improve the water solubility of lignin through sulfonation, but sulfonation alone does not increase the molecular weight of lignin, and cannot maximize its application performance. Molecular weight is one of the important structural indicators of lignin-based water-soluble polymers, and is an important factor affecting the ...

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Problems solved by technology

(1) Formaldehyde / acetone polycondensation method [CN101322927A; CN101709113A; CN101921639A; CN102923990A], this type of modified product has better dispersion and viscosity reduction ability, but the dosage is higher; a large amount of toxic reagent formaldehyde needs to be added, and the molecular weight increase is limited

(2) graft copolymerization method [CN1054078A; CN1071436A; CN1693342A; CN101440287A; CN102294199A; CN103301821A], this type of modification method is under the effect of initiator, unsaturated monomer is inserted in the lignin, and condition is harsh, and Lignin activity is low, resulting in a generally low grafting rate

(4) Alkylation reaction, the patent [US3407188] uses haloalkane or alkyl sulfate and lignin to produce Mannich reaction to prepare lignin quaternary ammonium salt, the alkyl chain adopts 1 to 4 carbons, and the long-chain halogenated hydrocarbon is then Difficult to react; U.S. patents [US7691982; US4781840] use halogenated hydrocarbons, alkyl sulfates and epoxy derivatives to carry out alkylation reactions on lignin, but the purpose is to improve the lipophilicity of lignin, which can be used in oil displacement agents and flotation agents, etc.; patents [CN1304950A; CN103254882A; US4739041; US5094295] use halogenated straight-chain alkanes as alkylating agents to introduce alkyl chains into lignosulfonate molecules to improve the lipophilicity of lignin, making it Both water and oil have a certain solubility, which has little influence on its molecular weight; patent [CN102580610A] prefers chlorinated paraffin to carry out alkylation modification on lignosulfonate, and synthesizes lignosulfonate alkylation modified surface Active agent, in the product aqueous solution that mass concentration is 1%, surface tension can be reduced to 29.299mN / m, but reaction condition is harsh, with the mixed solution of organic solvent (alcohol, ketone or ether) and water as solvent and with alkaline Organic amines (tetramethylammonium hydroxide, tetraethylammonium hydroxide, pyridine or pyridine derivatives) are catalysts and need to be reacted under the protection of an inert gas, which is not conducive to its industrial application

(5) Enzyme catalysis, patent [CN103088067A] uses peroxidase to catalyze the synthesis of high molecular weight sodium lignosulfonate polymer, the prepared sodium lignosulfonate polymer has a weight average molecular weight of 30000Da~100000Da, which improves the resistance to solid particles The dispersion performance of the suspension system, but the large dispersion and the high cost of peroxidase limit its application

[0005] Generally, researchers believe that the introduction of lipophilic alkyl chains into lignin or lignosulfonate will reduce water solubility, which is not conducive to the synthesis of high molecular weight, high water-soluble lignin-based polymers

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