Applications of polydimethyldiallylammonium chloride_industrial additives

Background and overview^[1][2]

Polydimethyldiallylammonium chloride is a water-soluble cationic polyquaternary ammonium salt (PDMDAAC for short). It has the characteristics of high positive charge density, good water solubility, high efficiency and non-toxicity, and wide pH adaptability. It is widely used in oil exploration, papermaking, mining, textile printing and dyeing, daily chemicals and water treatment fields.

Preparation^[1-2]

A preparation method for linear polydimethyldiallylammonium chloride, which includes the following steps: placing a dimethylamine solution with a concentration of 35% in a reaction kettle, slowly stirring at 20°C Add allyl chloride dropwise, and after 30 minutes, add a 15% sodium hydroxide solution at 10°C, then raise the temperature to 35°C, reflux for 8 hours, centrifuge and filter, and place the filtrate in a reaction kettle at 70 React under normal pressure at ℃ until the solid content is 69%, maintain the reaction temperature, and then add water to reduce the solid content of the reaction system to 34%. Then add the initiator to the reaction system, stop heating, and use natural photocatalysis while cooling down naturally. In 2h, viscous linear polydimethyldiallylammonium chloride was obtained.

Polydimethyldiallyl ammonium Chloride (PDMDAAC) is obtained from the homopolymerization of Dimethyldiallyl ammonium Chloride (DMDAAC) because of its It has the advantages of controllable relative molecular weight, high cationicity, high stability, and good water solubility. It is widely used in papermaking, coal mining, oil mining, textile printing and dyeing, medicine, biology, daily chemicals, water treatment and other fields. Since the PDMDAAC gel obtained by free radical polymerization of aqueous solution is inconvenient to transport, store and use, the dry powder preparation process of PDMDAAC has attracted much attention.

CN201611157520.9 provides a method for preparing PDMDAAC instant dry powder with a simple and stable process, low preparation cost and serialized characteristic viscosity.

The technical solution to achieve the purpose of the present invention is:

A method for preparing PDMDAAC instant dry powder, using PDMDAAC colloid with a characteristic viscosity value of 1.0-3.5dL/g and a solid content of 57.60%-69.30% as raw material, granulating to obtain PDMDAAC colloidal particles, and using two methods to prepare the colloidal particles Drying is carried out by programmed temperature rise. First, in the constant speed drying stage, maintain it at 60±5℃ for 20-50min, and then in the later stage of reduced speed drying, maintain it at 75-100℃ for 80-100min. The drying is completed. After pulverization, PDMDAAC dry powder with a characteristic viscosity value of 1.4-3.6dL/g is obtained.

Wherein, the size of the PDMDAAC colloidal particles is 2×2×20-6×6×50mm.

Apply^[3]

Polydimethyldiallylammonium chloride is a strong cationic polyelectrolyte that appears as a colorless to light yellow viscous liquid. It is safe, non-toxic, easily soluble in water, non-flammable, has strong cohesion and is hydrolytically stable. It has good properties, does not gel, is not sensitive to pH changes, and has chlorine resistance. It is widely used as a cationic coagulant in the sewage treatment industry. However, the current sewage treatment chemicals using polydimethyldiallylammonium chloride as the cationic coagulant have complex ingredients and require other higher-cost raw materials, resulting in higher production costs for finished drugs. As treatment needs become more and more extensive, traditional chemicals are not easy to promote and popularize.

CN201410014611.1 provides a chitosan and polydimethyldiallylammonium chloride complex with excellent performance, low cost, and easy promotion, and a preparation method. The present invention achieves the above object through the following technical solutions: a chitosan and polydimethyldiallylammonium chloride complex, including chitosan and polydimethyldiallylammonium chloride, said The mass part of chitosan is 1 part, and the mass part of the polydimethyldiallylammonium chloride is 3 to 8 parts. Chitosan is a derivative produced by partially removing the acetyl group of chitin. The chemical name is: β-(1,4)-2-amino-2-deoxy-D-glucose. Research has found that the chitosan molecular chain has There are many hydroxyl groups, amino groups, and some N-acetyl groups distributed in it. The existence of these groups makes chitosan exhibit many unique chemical properties. After the introduction of strongly positive quaternary ammonium salt groups, the cationic strength is greatly improved. Can enhance adsorption and flocculation performance. After synthesizing chitosan and polydimethyldiallylammonium chloride, chitosan introduced cationic groups to adsorb ��The flocculation performance is greatly enhanced. Specifically, the mass part of polydimethyldiallylammonium chloride is 5 parts.

The preparation method includes the following steps:

(1) Add glacial acetic acid to the reaction kettle, then add 1 part by mass of chitosan, and stir until completely dissolved;

(2) Fill the reaction kettle with nitrogen, and under nitrogen protection, add 3 to 8 parts by mass of polydimethyldiallylammonium chloride;

(3) Add an initiator, keep the temperature at 30°C to 70°C, and the reaction time is 3 to 6 hours to obtain a complex formed by the reaction between chitosan and polydimethyldiallylammonium chloride.

The beneficial effects of the present invention are:

The present invention synthesizes chitosan and polydimethyldiallylammonium chloride to prepare a complex, which has extremely strong adsorption and flocculation properties and can be used as an ideal chemical in the sewage treatment industry; chitosan serves as chitin Derivatives have wide sources, abundant reserves, low cost, and are not likely to cause secondary pollution. Therefore, this compound is suitable for large-scale promotion and popularization in the sewage treatment industry.

Main reference materials

[1] CN201811349522.7 Linear polydimethyldiallylammonium chloride and its preparation method

[2] CN201611157520.9 Preparation method of polydimethyldiallylammonium chloride instant dry powder

[3] CN201410014611.1 Chitosan and polydimethyldiallylammonium chloride complex and preparation method