Method for preparing sodium dimethyl isophthalate-5-sulfonate from high-concentration fuming sulfuric acid

A technology of dimethyl isophthalate and isophthalic acid, which is applied in the field of preparation of dimethyl isophthalate-5-sodium sulfonate (commonly known as three monomers), can solve the problem of uncontrollable reactions and product side effects. Many products, difficult to handle and other problems, to achieve the effect of improving product yield and quality, reducing the difficulty of refining, and reducing the amount of by-products produced

Active Publication Date: 2012-08-01
潍坊德润化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the production method reported at present is to use different concentrations of oleum or sulfur trioxide to sulfonate isophthalic acid, and then esterify with methanol, neutralize with soda ash or caustic soda, refine, and obtain the product, but use trioxide Sulfuration causes severe reaction and is difficult to control, so that isophthalic acid cokes, and low-concentration sulfuric acid sulfonation leads to too much residual sulfuric acid and finally produces a large amount of sodium sulfate, and there are many by-products in the product, and the mother liquor (high Concentration wastewater) is directly discharged from the system, which is difficult to handle and pollutes the environment

Method used

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  • Method for preparing sodium dimethyl isophthalate-5-sulfonate from high-concentration fuming sulfuric acid
  • Method for preparing sodium dimethyl isophthalate-5-sulfonate from high-concentration fuming sulfuric acid
  • Method for preparing sodium dimethyl isophthalate-5-sulfonate from high-concentration fuming sulfuric acid

Examples

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Embodiment 1

[0026] A method for preparing dimethyl isophthalate-5-sodium sulfonate with high-concentration oleum, comprising the following steps:

[0027] (1) Isophthalic acid and 65% oleum are mixed according to the weight ratio of 1: (0.92-1.08), and the sulfonation reaction is carried out at 150°C for 10 hours, and the reaction between isophthalic acid and SO3 in oleum is produced get sulfonated products;

[0028] (2) Adding methanol to the sulfonated product, and performing an esterification reaction at 50°C for 9 hours to obtain an esterified product; wherein the amount of methanol added is 1.40 times the weight of isophthalic acid;

[0029] (3) Add water 6 times the weight of isophthalic acid to the esterification product, and then add soda ash at 20°C to adjust the pH to 5-7.5 to obtain a neutralized material;

[0030] (4) Centrifuge the neutralized material, collect the neutralized mother liquor, then wash the material with water and centrifuge to obtain the crude dimethyl iso...

Embodiment 2

[0032] A method for preparing dimethyl isophthalate-5-sodium sulfonate with high-concentration oleum, comprising the following steps:

[0033] (1) Isophthalic acid and 65% oleum were mixed in a weight ratio of 1: (0.92-1.08), and sulfonated at 220°C for 8 hours to obtain a sulfonated product;

[0034] (2) Adding methanol to the sulfonated product, and performing an esterification reaction at 90°C for 6 hours to obtain an esterified product; wherein the amount of methanol added is 1.16 times the weight of isophthalic acid;

[0035] (3) Add water 6 times the weight of isophthalic acid to the esterification product, and then add soda ash at 55°C to adjust the pH to 5-7.5 to obtain a neutralized material;

[0036] (4) Centrifuge the neutralized material, collect the neutralized mother liquor, then wash the material with water and centrifuge to obtain the crude dimethyl isophthalate-5-sodium sulfonate, and collect the washed mother liquor; then add the crude isophthalic acid So...

Embodiment 3

[0038] Treat the neutralization mother liquor described in Example 1 through the following process: add 2-4 times the volume of methanol to the neutralization mother liquor, adjust the pH of the mixture to 4.5-5.5, and perform extraction and conversion reactions at a temperature of 50°C , the reaction time is 9 hours, sodium sulfate is precipitated, and the monomethyl isophthalate-5-sodium sulfonate and isophthalic acid-5-sodium sulfonate in the mother liquor are converted into dimethyl isophthalate-5- Sodium sulfonate (three monomers); then solid sodium sulfate is separated by solid-liquid separation, and the remaining liquid material is extracted by continuous distillation to methanol, and then solid sodium sulfate is separated by solid-liquid separation. The liquid material separated from sodium sulfate enters the continuous rectification tower, and methanol is extracted through rectification, and the methanol is returned to step (2) for reuse in the esterification process, ...

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Abstract

The invention relates to a chemical product preparation method, particularly a method for preparing sodium dimethyl isophthalate-5-sulfonate from high-concentration fuming sulfuric acid, which comprises the following steps: (1) mixing m-phthalic acid and 60-70% fuming sulfuric acid to carry out sulfonation reaction, thereby obtaining a sulfonated product; (2) adding methanol into the sulfonated product to carry out esterifying reaction, thereby obtaining the esterified product; (3) adding water into the esterified product, adding sodium carbonate at 20-55 DEG C to regulate the pH value to 5-7.5, thereby obtaining a neutralized material; and (4) separating and purifying the neutralized material, and drying to obtain the sodium dimethyl isophthalate-5-sulfonate finished product. The ternary-monomer generated in the invention has the advantage of high product quality, and the mother liquor process water can be utilized cyclically, thereby thoroughly implementing closed circulation of the process water and completely achieving zero discharge in the whole production process.

Description

technical field [0001] The invention relates to a method for preparing chemical products, in particular to a method for preparing dimethyl isophthalate-5-sodium sulfonate (commonly known as three monomers) using high-concentration oleum as a raw material and without waste water discharge. Background technique [0002] Dimethyl isophthalate-5-sodium sulfonate (commonly known as three monomers), the molecular formula is C10H9O2SNa, mainly used for the synthesis of the third monomer of cationic dyeable polyester (CDP), so that CDP polyester fiber is suitable for cationic fuel With good affinity properties, CDP fibers can be dyed under normal pressure. After dyeing, the color is bright, the color spectrum is complete, the color fastness is high, and it is not easy to fade. It also has good antistatic, hygroscopicity, anti-pilling and air permeability. comfortable to wear. However, the production method reported at present is to use different concentrations of oleum or sulfur tr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C309/58C07C303/32
Inventor 刘旭思隋福龙
Owner 潍坊德润化学有限公司
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