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3-hydroxy benzoate preparation method

Inactive Publication Date: 2010-07-14
HEBEI BAIQI PHARMA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0010] Method 1: low yield
In order to ensure that the moisture content of the product is qualified, it takes a long drying time and the need to distill water in the post-treatment process is the disadvantage of this process
[0011] Method 2: Decompression and water removal during the operation process, the use of a large amount of organic solvents (increasing the cost and making the operating environment harsh) and the residual solvent of the final product are the undesirable points of this scheme
[0012] Method 3: Remove water under reduced pressure, use solvent (increase the production cost of the final product), and the problem of solvent residue in the final product is the shortcoming of this process

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0031] Drop into 2kg of 3-hydroxybenzoic acid (purity ≥ 99.5%) in the reactor, add water 3000ml, stir to make the material in the reactor be slurry, control the internal temperature of the reaction system between 25 ℃ ~ 35 ℃, add dropwise 900 grams (purity ≥ 99.5%) 90%) KOH dissolved in 2500g water lye, until the reaction system PH = 6.4 ~ 6.5, add 60g of activated carbon to the system, stir at room temperature for 30 minutes, decarbonize and filter, spray dry the mother liquor, the inlet temperature is 150°C ~ 190°C, the outlet temperature 70°C-90°C, after spray drying, 2336g of dry solid was obtained, and the molar yield was 91.5%. Product testing results: moisture <1.0%, purity 99.73%.

Embodiment 2

[0033] Add 2 kg of 3-hydroxybenzoic acid (purity ≥ 99.5%) into the reactor, add 1500 ml of water and stir to make the material in the reactor slurry, control the internal temperature at 50°C to 65°C, and add 900g (purity ≥90%) of KOH solution dropwise. Add lye in 1500ml of water until the pH of the reaction system is 6.4~6.5, add 60g of activated carbon to the system, keep the internal temperature at 50℃~65℃, stir and decolorize for 30 minutes, decarbonize and filter, spray dry the mother liquor, and the inlet temperature is 170℃~180℃ , The outlet temperature is 75°C to 85°C. (in the present embodiment: acid: water=1:1.5, because the consumption of water is minimum, the 3-hydroxybenzoate aqueous solution concentration is higher. During spray drying: when the spout of atomizer is moderate in material spray velocity, can not Blockage; if the spray flow rate of the material is adjusted to the highest, the nozzle of the atomizer will occasionally form tiny solid blocks; if the con...

Embodiment 3

[0035] Add 2 kg of 3-hydroxybenzoic acid (purity ≥ 99.5%) in the reactor, add 6000 ml of water and stir to make the material in the reactor slurry, control the internal temperature at 50 ° C to 65 ° C, and drop 860 g (purity ≥ 98%) to obtain Na 2 o 3 Dissolve lye in 4000ml of water until the pH of the salt-forming system is 6.4~6.5, add 70g of activated carbon to the system, keep the internal temperature at 50℃~60℃, stir and decolorize for 30 minutes, decarbonize and filter, spray dry the mother liquor, and the inlet temperature is 158℃~ 190℃, outlet temperature 80℃~95℃. After spray drying, 2110 g of dry solid was obtained, and the molar yield was 91%. Product testing results: moisture <1.0%, purity 99.75%.

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Abstract

The invention discloses a preparation method for 3-hydroxyl benzoate, which comprises the following steps: aqueous solution of the 3-hydroxyl benzoate is prepared, and by adopting the processing method of spray drying, the 3-hydroxyl benzoate is obtained. The product obtained by adopting the method is even in particle size, low in residual water content, high in yield and purity, and good in fluidity.

Description

technical field [0001] The invention relates to a preparation method of 3-hydroxybenzoate, in particular to a preparation method of 3-hydroxybenzoic acid monopotassium salt or monosodium salt. Background technique [0002] 3-Hydroxybenzoate is a food additive similar to sodium benzoate and potassium sorbate. 3-Hydroxybenzoate potassium or sodium salt (Potassium 3-hydroxybenzoate, Sodium 3-hydroxybenzoate) its general formula is [0003] [0004] where R=K,Na [0005] At present, the method for preparing 3-hydroxybenzoic acid salt has three kinds: [0006] (1) Put 3-hydroxybenzoic acid into the reactor, add 5 times of water, and then add a certain amount of KOH (or NaOH, NaOH 2 CO 3 , NaHCO 3 , K 2 CO 3 , KHCO 3 Any one of them) was stirred at an internal temperature of 50°C to 60°C for 30 minutes, filtered and decolorized, then distilled under reduced pressure to a slurry state, cooled to crystallize, and dried to obtain the finished product with a yield of 78%. ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C65/03C07C51/41
Inventor 任秋栓孙文健李明海
Owner HEBEI BAIQI PHARMA
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