Method for synthesizing trioxymethylene

Abstract

The invention provides a method for synthesizing trioxymethylene. The method comprises the step of carrying out a reaction at 30-150 DEG C for 0.1-5 hours to synthesize trioxymethylene by using an ionic liquid as a solvent and a catalyst and solid paraformaldehyde as a raw material, wherein the use amount of the solid paraformaldehyde is not more than 80% of total mass of the ionic liquid and the solid paraformaldehyde. By using the solid paraformaldehyde as the raw material and the ionic liquid as the solvent and the catalyst, the method provided by the invention is free of byproducts such as methyl formate, methanol, methylal and the like, and can remarkably improve the balanced yield of trioxymethylene and reduce the energy consumption, and the ionic liquid can be repeatedly used, so that the production cost is lowered.

Description

technical field [0001] The invention relates to a method for synthesizing paraformaldehyde, in particular to a method for synthesizing paraformaldehyde from solid paraformaldehyde by using an ionic liquid as a solvent and a catalyst, and belongs to the technical field of chemical synthesis. Background technique [0002] Paraformaldehyde (TOX) and many related industries are extremely important links in the carbon-one chemical industry chain. First of all, TOX is the raw material for the preparation of polymethoxy dimethyl ether (DMM3-8), and DMM3-8 is an internationally recognized new type of environmentally friendly fuel oxygen-containing component that reduces fuel consumption and smoke emissions, and is internationally recognized The new environment-friendly diesel blending component has a cetane number as high as 76, an oxygen content of 47%-50%, no sulfur and no aroma, and the blending amount can account for 10%-20% of the diesel amount, which can significantly reduce t...

AI Technical Summary

Problems solved by technology

But no matter what type of catalyst is used, the biggest problem of these methods for synthesizing TOX based on formaldehyde aqueous solution is that the formaldehyde solution needs to be concentrated to more than 50% (the concentration of the formaldehyde solution used in the examples of the above-mentioned patent documents is all greater than 50%) , and the TOX productive rate in the reaction phase is very low (the equilibrium productive rate of TOX in the reactor liquid is only about 2.5% and 1.8% respectively when the above-mentioned conditions are catalyzed with sulfuric acid and ionic liquid, mass percentage), simultaneously formic acid, formic acid Formation of methyl esters, etc., so reactive distillation process must be used to produce TOX

As everyone knows, the latent heat of vaporization of water is very high, therefore, the separation energy consumption of above-mentioned technology is very high, and the required energy consumption of preparing TOX is mostly used for evaporating water (see Mosamoto, J., etal.Synthesissoftrioxaneusingheteropolyacidsascatalyst.Angew.Chem.Int .Ed.2000,39,2102)

On the other hand, the biggest problem of POM engineering plastics is the high energy consumption of production (see Zhang Xinggang for details, and then look at the "Great Leap Forward" of the POM industry. Chemical Management 2011, December, 43), and 75% of the energy consumption comes from monomers Production of TOX (see Grützner, T., et al. Chem. Eng. Sci. 2007, 62, 5613 for details)

At the same time, this type of process also generally has the problem of recovery and treatment of dilute formaldehyde. The recovery of dilute formaldehyde basically adopts a distillation scheme, which has a large recovery volume, high energy consumption, high requirements on equipment materials, and large investment (see Zhang Xinggang for details; see polyoxymethylene again. Industry "Great Leap Forward"; Chemical Management 2011,12,43)

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