Purifying method of dimethyl diallyl ammonium chloride monomer

Abstract

The invention discloses a purifying method of dimethyl diallyl ammonium chloride monomer. The purifying method comprises the following steps of: low-temperature material recycling, medium-temperature desalination and concentration, high-temperature desalination and concentration and temperature-reducing centrifugal desalting, and simultaneously also comprises the following steps of: active-carbon decoloring and low-temperature freezing and desalting. The dimethyl diallyl ammonium chloride monomer solution obtained by purification of the method is light in color, fewer in impurity and high in purity, and the content of the amine salt and the content of chloride ions are greatly reduced compared with the those of the existing purifying method.

Description

technical field [0001] The invention relates to a method for purifying a compound, in particular to a method for purifying a dimethyl diallyl ammonium chloride monomer. Background technique [0002] Dimethyl diallyl ammonium chloride monomer ((CH 2 = CH-CH 2 ) 2 N + (CH 3 ) 2 CL - ) is a cationic monomer with a wide range of uses. Its aqueous solution is a colorless transparent liquid. It is mainly used to synthesize water-soluble polymers containing organic cations. It can improve the water solubility of polymers, rheology of solutions, increase adsorption capacity and sterilize Its copolymer has a wide range of uses in water treatment, oil exploration, textile printing and dyeing, daily chemical industry and other fields. [0003] At present, dimethyl diallyl ammonium chloride monomer is prepared by one-step method, that is, dimethylamine (2(CH 3 ) 2 NH), allyl chloride (CH 2 =CH-CH 2 CL) and alkali (NaOH) as raw materials, the reaction equation is as follows:...

AI Technical Summary

Problems solved by technology

This purification method has the following two disadvantages: (1) After the synthesis reaction is completed, there are 5-10% unreacted dimethylamine and chloropropene in the solution. Since they are not removed, they will undergo other side reactions after heating up to generate allyl Alcohols and ethers increase the types and contents of impurities in the system, and also cause waste of raw materials dimethylamine and chloropropene; (2) directly cool down after vacuum concentration, separate and remove salt, and obtain monomers. There are also some other by-products in the monomer obtained in this way, such as tertiary amine salt, quaternary ammonium salt and sodium chloride, which have not been removed, resulting in the final product with many impurities, low purity, darker color, and relatively low activity of the monomer. Poor, inconsistent yield and quality

Therefore the product impurity that obtains with existing purification method is many, and purity is low, and color and luster is dark, and the content of amine salt and chloride ion is high, and the quality of dimethyl diallyl ammonium chloride monomer is poor, output is low

Images