Prepn of cationic monomer dialkyl disubstituent propyl ammonium halide

Abstract

The preparation method of high-purity cationic monomer dialkyl disubstituent allyl ammonium halide includes tertiary amination, neutralization reaction and tertiary amination reaction and quaterisation, in the reactor still with back-flow condensation device adding substituent halopropylene and dialkyl amine aqueous solution, adding a certain quantity of water to regulate water-phase and oil-phase, drop-adding sodium hydroxide aqueous solution, uniformly mixing, heating and heat-insulating, reduced pressure distillation, reduced pressure filtering of centrifugal filtering to remove crystal sodium chloride, decolouring said solution by using active carbon, then filtering to remove action carbon to obtain the invented product. Said invented reactions can be implemented under the condition of low temperature.

Description

1. Technical field [0001] The invention relates to a one-step method for preparing a cationic monomer for polymer synthesis, in particular to a method for preparing a high-purity cationic monomer dialkyl disubstituent allyl ammonium halide. 2. Background technology [0002] Dialkyl disubstituent allyl ammonium halide is a kind of cationic quaternary ammonium salt, its general formula is as follows: [0003] Among them, R 1 Preferably hydrogen atom or C 1～4 An alkyl group, R is preferably a hydrogen atom or C 1～18 The alkyl group, Y is preferably halogen. Dimethyldiallylammonium Chloride (DMDAAC for short) is the most ideal cationic monomer in this class of compounds. DMDAAC is an excellent water-soluble quaternary ammonium salt containing two unsaturated double bonds. It is a white needle-like crystal with a melting point of 146°C to 147°C. It easily absorbs moisture in the air and becomes an aqueous solution. Therefore, the compound mostly exists in the form of aqueo...

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Problems solved by technology

The above-mentioned various processes all have the same problem: either the reaction time at low temperature is too long, the material ratio cannot be kept stable, the reaction cannot be completed, and the increase of impurities leads to low polymerization activity of the product; or under high temperature conditions, pressure is generally required to prevent material overflow , but the side reaction is intensified at high temperature, although the reaction cycle is shortened, the purity is still affected, resulting in low polymerization activity of the product

[0018] As can be seen from the above, the defects in the existing method are: (1) in the one-step preparation process of the cationic monomer dialkyl diallyl ammonium halide, in order to keep the material ratio of the raw materials, prevent spillage, and prevent side effects such as hydrolysis and oxidation reaction, or use the method of reaction at low temperature, but the loss of materials still exists in the open system for a long time and the production cycle is long, or use the method of reaction at high temperature, but in order to prevent the material from overflowing, it is necessary to seal and pressurize, and the side reaction is intensified at this time. Directly affect the purity of the reaction product; (2) under low temperature, the method of alternating feeding in stages and the method of alternating feeding under high temperature and pressure can partially solve the above-mentioned shortcomings, but the method of alternate feeding is not only complicated in the feeding process, but also difficult in actual production and operation. Controlling the ratio of feeding generally requires the addition of an indicator to indicate that the pH value is neutral (document 8), or continuous sampling and analysis to determine the pH value is used to adjust the amount of dosing (document 7)

This will not only affect the polymerization reactivity of the product due to the introduction of new impurities, but also is extremely inconvenient in industrial operation; (3) in the one-step preparation process announced so far, the use of high concentration Dimethylamine and sodium hydroxide solution, which will inevitably lead to intensified hydrolysis side reactions and increased impurities in the product

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