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Method for producing ultralow-acid formaldehyde

A production method and ultra-low acid technology, which can be used in the separation/purification of carbonyl compounds, organic chemistry, etc., and can solve problems such as the impact of product stability

Inactive Publication Date: 2018-08-03
ANHUI JINGHE IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the formaldehyde solution prepared by the catalytic oxidation method, the finished formaldehyde often contains a certain amount of formic acid, which affects the stability of the product

Method used

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  • Method for producing ultralow-acid formaldehyde

Examples

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Effect test

example 1

[0019] Such as figure 1 As shown, the 37% formaldehyde solution produced by formaldehyde has an acid content of 0.03% after testing. It is pumped into the first adsorption tower, and the formaldehyde solution enters the tower from bottom to top for adsorption. The flow rate is 20m 3 / h, after being adsorbed by D301 weakly basic macroporous anion exchange resin, the acid content in formaldehyde is detected to be 0.002%; after a period of time, when the acid content in ultra-low acid formaldehyde is detected to be ≧0.005%, switch to the second adsorption tower , immediately regenerate the first adsorption tower, using 3~5% NaOH solution, the flow rate of regeneration lye is 3~5m / s, the regeneration time is 1~2h, and after washing with desalinated water, the pH of the adsorption tank reaches 7.2~8.0, which can be cycle adsorption.

example 2

[0021] The 37% formaldehyde solution produced by formaldehyde has an acid content of 0.04% after testing. It is pumped into the first adsorption tower, and the formaldehyde solution enters the tower from bottom to top for adsorption. The finished product goes to the ultra-low acid formaldehyde product tank, and the pumping flow rate is 20m 3 / h, after being adsorbed by D301 weakly basic macroporous anion exchange resin, the acid content in formaldehyde was detected to be 0.003%. After a period of time, when the acid content in ultra-low-acid formaldehyde is detected to be ≧0.005%, switch to the second adsorption tower, and immediately regenerate the first adsorption tower, using 3~5% NaOH solution, and the flow rate of the regenerated lye is 3~5m / s, the regeneration time is 1~2h, and after washing with desalinated water, the pH of the adsorption tank reaches 7.2~8.0, which can be recycled for adsorption.

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Abstract

The invention relates to a method for producing ultralow-acid formaldehyde. The method comprises the following steps: a, pumping 37% formaldehyde obtained by a catalytic oxidation reaction into a first anion exchange resin adsorption tower, adsorbing formic acid in the 37% formaldehyde by using weakly basic anion exchange resin in the first anion exchange resin adsorption tower, and conveying thefinished formaldehyde product obtained after the adsorption into a formaldehyde storage tank; b, timely switching a transfer pump to a second anion exchange resin adsorption tower (2) when the detected acid content of formaldehyde is equal to or more than 0.005%, continuously adsorbing the formic acid in the 37% formaldehyde by the weakly basic anion exchange resin, and conveying the finished formaldehyde product obtained after the adsorption into the formaldehyde storage tank; and c, regenerating the first anion exchange resin adsorption tower by a 3-5% NaOH solution in a forward flow manner,washing the first anion exchange resin adsorption tower with desalinated water, and continuously putting the regenerated first anion exchange resin adsorption tower into production and use. The method has the advantages of continuousness in production of the ultralow-acid formaldehyde, and meeting the needs of the market.

Description

technical field [0001] The invention belongs to the technical field of chemical production and relates to a production method of ultra-low acid formaldehyde. Background technique [0002] Formaldehyde, chemical formula HCHO, formula weight 30.03, also known as formaldehyde. It is a colorless gas with a special irritating odor, which is irritating to human eyes and nose. The relative density of the gas is 1.067 (air = 1), and the density of the liquid is 0.815g / cm³ (-20°C). Melting point -92°C, boiling point -19.5°C. Soluble in water and ethanol. The concentration of the aqueous solution can be up to 55%, usually 40%, called formaldehyde water, commonly known as formalin (formalin), is a colorless liquid with a pungent smell. Formaldehyde can be produced by dehydrogenation or oxidation of methanol under the catalysis of silver, copper and other metals, and can also be separated from hydrocarbon oxidation products. Used as pesticides and disinfectants, raw materials for ma...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C45/79C07C47/04
CPCC07C45/79C07C47/04
Inventor 夏家信施以军
Owner ANHUI JINGHE IND
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