阅读说明：本技术 一种对苯二甲酸的制备方法 (Preparation method of terephthalic acid ) 是由 王存亮 许灵艳 严学文 黄焕军 王小桥 于 2018-06-27 设计创作，主要内容包括：本发明公开了一种对苯二甲酸的制备方法,在高锰酸钾溶液中加入一定量的对二甲苯,搅拌控温60-90℃,反应1-3h,调节pH为11-13,过滤,分液,取水相,调节pH为0.5-2,过滤得对苯二甲酸固体；本发明合成简单,无需高压条件,污染小。(The invention discloses a preparation method of terephthalic acid, which comprises the steps of adding a certain amount of p-xylene into a potassium permanganate solution, stirring, controlling the temperature to be 60-90 ℃, reacting for 1-3h, adjusting the pH to be 11-13, filtering, separating liquid, taking a water phase, adjusting the pH to be 0.5-2, and filtering to obtain a terephthalic acid solid; the invention has simple synthesis, no need of high pressure condition and little pollution.)

1. A method for preparing terephthalic acid is characterized in that: adding a certain amount of p-xylene into potassium permanganate solution, stirring, controlling the temperature to be 60-90 ℃, reacting for 1-3h, adjusting the pH to be 11-13, filtering, separating liquid, taking a water phase, adjusting the pH to be 0.5-2, and filtering to obtain terephthalic acid solid.

2. A process for producing terephthalic acid according to claim 1, characterized in that: the potassium permanganate (pure): p-xylene =1: 0.25-0.35 (weight ratio).

Technical Field

The invention belongs to the field of compound synthesis, and particularly relates to a preparation method of terephthalic acid.

Background

The synthesis process of terephthalic acid includes 1, oxidizing p-xylene in acetic acid solvent, cobalt acetate-manganese acetate catalyst and tetrabromoethane as cocatalyst at high temperature and high pressure to produce terephthalic acid while eliminating p-carboxybenzoic acid; 2, oxidizing paraxylene in acetic acid solvent at 130 deg.C and 3MPa with air, washing reaction product with acetic acid, and drying to obtain terephthalic acid. The existing synthesis conditions need various catalytic oxidants, high pressure is needed for the synthesis conditions, impurities are also needed to be removed after synthesis, and the conditions are complicated.

Disclosure of Invention

The invention aims to provide a preparation method of terephthalic acid, which has simple synthesis, does not need high pressure condition and has little pollution.

Adding a certain amount of p-xylene into a potassium permanganate solution, stirring, controlling the temperature to be 60-90 ℃, reacting for 1-3 hours, adjusting the pH to be 11-13, filtering, separating liquid, taking a water phase, adjusting the pH to be 0.5-2, and filtering to obtain a terephthalic acid solid.

Potassium permanganate (pure) in the invention: p-xylene =1: 0.25-0.35 (weight ratio).

The invention has the beneficial effects that: the synthesis is simple, high pressure conditions are not needed, and the pollution is small.

Detailed Description

Adding 150g of 50% potassium permanganate aqueous solution into a 250mL flask, dropwise adding 22.5g of p-xylene, vigorously stirring, heating to 75 ℃, reacting for 2h, adjusting the pH to be =12 by 40% sodium hydroxide, carrying out vacuum filtration, separating, taking a water phase, adjusting the pH to be =0.5 by 4mol/L, and carrying out vacuum filtration to obtain a terephthalic acid solid.