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Method for preparing concentrated formaldehyde from low-formaldehyde-content materials

A formaldehyde content, concentrated formaldehyde technology, applied in the field of preparation of concentrated formaldehyde, can solve the problems of reducing formaldehyde, formaldehyde is easy to oxidize, corrode equipment, etc., and achieve the effect of simple preparation process, easy industrialization, and long cycle life

Inactive Publication Date: 2017-08-04
江苏道尔顿石化科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the process of producing paraformaldehyde, formaldehyde will be concentrated and extracted, and a large amount of dilute formaldehyde will be produced. How to deal with dilute formaldehyde has become a difficult problem for paraformaldehyde manufacturers. Most of the disclosed methods are only from the point of view of environmental protection, using chemical conversion method to convert formaldehyde into environmentally acceptable emissions, or using biochemical treatment methods, there are many shortcomings in these methods to deal with dilute formaldehyde: the conversion is not complete, due to side effects When the reaction occurs, part of the formaldehyde is further converted into formaldehyde and formate, so the solution after conversion treatment cannot be discharged directly; formaldehyde is converted into formaldehyde polysaccharides, which cannot be recycled and reused, resulting in waste of resources
In order to increase the concentration of formaldehyde, the existing technology includes distillation or washing, or reacting formaldehyde with alcohol to form hemiacetal. Since the concentration is not high enough, it must be evaporated by heating to obtain formaldehyde-enriched gas. This process requires quite strict reaction conditions. Reaction equipment also requires a lot of energy consumption
[0004] CN102329407A discloses a process for the recycling of dilute formaldehyde produced in the production of paraformaldehyde, breaking the chemical interaction between methanol-formaldehyde, methanol-water and formaldehyde-water-derivatives in formaldehyde wastewater by physical means The relationship between formaldehyde and water has achieved the separation of formaldehyde and water. However, during the concentration process, formaldehyde is easily oxidized to produce formic acid concentration. Reducing the yield of formaldehyde not only affects the production in the subsequent section, but also buryes hidden dangers for long-term stable production. The corrosion of equipment is serious. Equipment maintenance costs a lot

Method used

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  • Method for preparing concentrated formaldehyde from low-formaldehyde-content materials
  • Method for preparing concentrated formaldehyde from low-formaldehyde-content materials
  • Method for preparing concentrated formaldehyde from low-formaldehyde-content materials

Examples

Experimental program
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Effect test

Embodiment 1

[0051] 1) Collect the intermediate product in the process of producing polyoxymethylene dimethyl ether, wherein the concentration of formaldehyde is 5wt%, add methanol to the intermediate product, wherein the volume ratio of methanol to the intermediate product is 0.2:1, and then add the loaded Phosphotungstic acid catalyst, made into slurry, stirred and reacted to obtain methylal; wherein, the relevant parameters and preparation conditions of the catalyst catalyst are shown in Table 1, and the mass ratio of the added catalyst to the intermediate product is 0.5:1;

[0052] 2) Under the oxygen partial pressure of 0.2 and 320°C, the methylal obtained in step 1) is catalyzed and oxidized under the action of iron molybdate, molybdenum trioxide and catalytic promoter, and the product is collected. The relevant parameters of the catalyst are shown in Table 2, which are spherical particles with a diameter of 1 mm.

Embodiment 2

[0056] 1) Collect the intermediate product in the process of producing paraformaldehyde, wherein the concentration of formaldehyde is 25wt%, add methanol to the intermediate product, wherein the volume ratio of methanol to the intermediate product is 0.8:1, then add the loaded phosphotungstic acid catalyst , making a slurry, stirring reaction to obtain methylal; wherein, the relevant parameters and preparation conditions of the catalyst catalyst are as shown in Table 1, and the mass ratio of adding the catalyst to the intermediate product is 1.2:1;

[0057] 2) Catalytic oxidation of the methylal obtained in step 1) under the action of iron molybdate, molybdenum trioxide and catalytic promoter under the oxygen partial pressure of 0.5 and 350° C. to collect the product. The relevant parameters of the catalyst are shown in Table 2, which are spherical particles with a diameter of 2 mm.

Embodiment 3

[0059] 1) collect the intermediate product of DMMn production process, wherein the concentration of formaldehyde is 10wt%, methanol is added in this intermediate product, wherein the volume ratio of methanol and this intermediate product is 0.5:1, then add load-type phosphotungstic acid catalyst, prepare Become slurry, stirring reaction obtains methylal; Wherein, the relevant parameter of catalyst catalyst and preparation condition are as shown in table 1, the mass ratio of adding catalyst and intermediate product is 0.6:1;

[0060] 2) Under the oxygen partial pressure of 0.3 and 335°C, the methylal obtained in step 1) is catalyzed and oxidized under the action of iron molybdate, molybdenum trioxide and catalytic promoter, and the product is collected. The relevant parameters of the catalyst are shown in Table 2, which is a hollow cylindrical ring structure with an outer diameter of 5.5 mm, an inner diameter of 2.5 mm, and a height of 5 mm. Dilute formaldehyde is returned to s...

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Abstract

The invention relates to a method for preparing concentrated formaldehyde from low-formaldehyde-content materials. The method includes steps: (1) adding methyl alcohol into the low-formaldehyde-content materials, and performing reaction under the catalysis action of a heteropolyacid catalyst to obtain dimethoxymethane; (2) subjecting dimethoxymethane obtained at the step (1) to catalytic oxidation to obtain products including concentrated formaldehyde, wherein a concentrated formaldehyde product being 65-66wt% in concentration is obtained finally, and the formaldehyde recovery rate in the whole process is 97% or above. The method has advantages that special equipment for concentrating of dilute formaldehyde into concentrated formaldehyde is not needed, so that cost saving and energy consumption reduction are realized; circulation of dilute formaldehyde in a device is realized, independence from production by-products such as dimethoxymethane, urotropin or the like is realized, and COD level of wastewater and wastewater treatment cost are reduced.

Description

technical field [0001] The invention relates to the technical field of chemical production, in particular to the field of preparation of formaldehyde, polyoxymethylene dimethyl ether, polyoxymethylene, gaseous formaldehyde and glyphosate, and in particular to a method for preparing concentrated formaldehyde from materials with low formaldehyde content. Background technique [0002] The production of paraformaldehyde uses formaldehyde as the main raw material. Solid formaldehyde is obtained through evaporation, concentration, and catalytic condensation, and then the finished product is obtained by vacuum drying. However, in the process of producing paraformaldehyde, formaldehyde will be concentrated and extracted, and a large amount of dilute formaldehyde will be produced. How to deal with dilute formaldehyde has become a difficult problem for paraformaldehyde manufacturers. Most of the disclosed methods are only from the point of view of environmental protection, using chemi...

Claims

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Application Information

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IPC IPC(8): C07C45/51C07C47/04
CPCC07C41/56C07C45/513C07C47/04C07C43/30
Inventor 鄢小明
Owner 江苏道尔顿石化科技有限公司
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