Production method for alkyl ketene dimer

Abstract

The invention relates to a production method of an alkyl ketene dimer. The production method is characterized in that tertiary amine reacts with acyl chloride according to a molar ratio of (1:1.6)-(1:5.0) at 30-65 DEG C and under a negative pressure, generated reaction heat is taken away by vaporization of amine, amine steam returns to a reaction kettle after being condensed and liquefied by a condenser at the top of the reaction kettle and is circulated, reaction materials enter an amine evaporation kettle after a condensation reaction is finished, and superfluous tertiary amine is distilled and recovered through the amine evaporation kettle. According to the production method of the alkyl ketene dimer, a solvent does not need to be added, the reaction is carried out at the higher molar ratio and the lower temperature, and the problems that the viscosity of a reaction system is high, the stirring is difficult, diketone side products in reaction products at the high temperature are more and the like are solved; and an alkyl ketene dimer product produced by the production method is high in purity, low in cost and little in output of effluent brine, and the produced alkyl ketene dimer product can be used as sizing agents prepared from foods or other high-performance paper products.

Description

technical field [0001] The invention relates to a production process for generating alkyl ketene dimers by reacting acid chlorides and tertiary amines, which belongs to the field of chemical industry. Background technique [0002] Alkyl Ketene Dimer (AKD for short, hereinafter referred to as AKD) is a neutral sizing agent for papermaking, which is produced by the reaction of C8-C22 alkyl or alkenyl acid chlorides and tertiary amines, and then Dimerization of alkyl ketene, after corresponding separation and treatment, AKD product is obtained. The synthesis reaction process of AKD is as follows: [0003] [0004] This reaction has the characteristics of large heat release and insoluble tertiary amine hydrochloride in the reaction process, resulting in high viscosity of the system. Currently, industrial AKD production methods can be divided into solvent-free and intermittent / continuous. The difference in process results in great differences in process difficulty, product qu...

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Problems solved by technology

[0005] Patent CN1156724A discloses a method for producing AKD with a solvent gap. Due to the presence of solvent toluene, the use of AKD products is limited and the energy consumption of the production process is high; patent CN1596252A discloses a method for continuously preparing AKD without solvent. The excess of triethylamine is relatively small, and the viscosity of the reaction material system is high, so it needs to be carried out under strong stirring such as an extruder, a kneader, etc., and the reaction conditions are harsh; patent CN 101845030 A also discloses a method for continuous preparation of AKD. Divide the formula amount of acid chloride into 2 or 3 parts, and add them to the conveyor reactor with intermittent screw blades in sections. The heat of reaction is taken away by the cooling water in the inner hollow shaft and the outer jacket. The heat transfer capacity is poor, and the operation complex

[0006] In a word, in summary, most of the prior art described above is carried out under relatively low ratio conditions of acid chlorides and tertiary amines, the viscosity of the system is high, the stirring and mass transfer are difficult, the reaction temperature is high, the product purity is low, and the amount of waste brine is large.

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