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Method for producing 3,5-di-tert-butyl-4-hydroxybenzoic acid

A technology of hydroxybenzoic acid and di-tert-butyl, which is applied in 3 fields and can solve the problems of small filling weight and increasing filling weight

Inactive Publication Date: 2006-11-15
UENO FINE CHEM IND LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, when filling packaging materials such as paper bags, the filling weight is small, and in order to increase the filling weight, a degassing process is required, and a large space is required for storage.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0019] In the preparation method of DBPOB of the present invention, an acid is added to the aqueous solvent solution containing the above-mentioned DBPOB alkali metal salt and alkali metal bicarbonate to carry out acid analysis.

[0020] As the alkali metal bicarbonate used in the present invention, sodium bicarbonate and / or potassium bicarbonate are preferably used.

[0021] The concentration of the alkali metal bicarbonate in the aqueous solvent solution supplied to the acid precipitation step in the present invention is preferably 0.3-10% by weight, particularly preferably 1-7% by weight.

[0022] When the concentration of the alkali metal bicarbonate is less than 0.3% by weight, the obtained DBPOB has a low bulk density, and the effect of the present invention cannot be obtained. When the concentration of the alkali metal bicarbonate exceeds 10% by weight, a large amount of acid must be used for acid precipitation, the calorific value during acid precipitation increases, a...

Embodiment 1

[0042] With DBPOB (Ueno Pharmaceutical Co., Ltd.), 48% aqueous sodium hydroxide solution (Kaiyaku Co., Ltd.), sodium bicarbonate (Wako Pure Chemical Industry Co., Ltd.) and water prepare the aqueous solution 1588g of composition as shown in Table 1. The obtained aqueous solution was transferred to a four-neck glass flask equipped with a thermometer, a pH meter, and a stirring blade, and the temperature was raised to 50° C. while stirring in a nitrogen atmosphere. Next, while maintaining this temperature, 70% sulfuric acid was added dropwise over 1 hour to adjust the pH to 3.5 and conduct acid precipitation.

[0043] The DBPOB slurry obtained by acid analysis was separated into solid and liquid at 3000rpm (centrifugal effect: 600G) with a small centrifuge (SYK-5000-15A, manufactured by Sanyo Chemical Machinery Co., Ltd.). The solid content obtained after separation was ventilated and dried at 70° C. for 12 hours, and the drying loss was calculated. The smaller the drying reduc...

Embodiment 2-4 and comparative example 1-2

[0046] Except that the aqueous solution weight, the concentration of DBPOB sodium salt and the concentration of sodium bicarbonate are changed as shown in Table 1, carry out the operation of acid analysis, centrifugation and drying in the same way as in Example 1. The values ​​of drying loss and apparent bulk density are shown in Table 1.

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PUM

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Abstract

The present invention provides a method for preparing 3,5-di-tert-butyl-4-hydroxybenzoic acid capable of obtaining high-purity 3,5-di-tert-butyl-4-hydroxybenzoic acid with good production efficiency. The present invention relates to 3,5-di-tert-butyl-4-hydroxybenzoic acid comprising the step of acidifying an aqueous solvent solution containing an alkali metal salt of 3,5-di-tert-butyl-4-hydroxybenzoic acid with an acid The preparation method is characterized in that the aqueous solvent solution also contains alkali metal bicarbonate with a concentration of 0.3-10% by weight.

Description

technical field [0001] The invention relates to a preparation method of 3,5-di-tert-butyl-4-hydroxybenzoic acid. Background technique [0002] The use of 3,5-di-tert-butyl-4-hydroxybenzoic acid (hereinafter referred to as DBPOB) as an ultraviolet absorber or an antioxidant for polymer materials such as polypropylene, and its use as a pressure-sensitive recording paper are known. It is widely used in various applications such as the use of a toner and the use as a raw material for synthesizing chemicals such as pharmaceuticals and agricultural chemicals. [0003] As a production method of DBPOB, for example, a production method using the Kolbe-Schmitt reaction is known, wherein at a specific temperature, a basic alkali metal compound such as sodium hydroxide or sodium methoxide is mixed with an excess amount of 2,6- Di-tert-butylphenol (hereinafter referred to as DTBP) is reacted to obtain alkali metal 2,6-di-tert-butylphenolate, which is reacted with carbon dioxide (see Jap...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/02C07C65/03
Inventor 大塚良一千足政典
Owner UENO FINE CHEM IND LTD
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