Phenol purifying method

Abstract

The invention discloses a phenol purifying method with two-stage solid acid catalyst process. In the phenol purifying method, common industrial catalyst refined phenol is used, the process is simple, the energy consumption is low, and the product at least can satisfy the requirement of epoxide-resin-level bisphenol A, i.e. the requirement of high-level pure phenol.

Description

technical field [0001] The invention belongs to the field of phenol purification methods, in particular to a method for purifying phenol through a two-stage solid acid catalyst process. Background technique [0002] At present, 90% of phenol in the world is produced by cumene method. The production of phenol by the cumene method is based on cumene as a raw material. First, cumene hydroperoxide is generated through air oxidation, and the latter decomposes to generate phenol and acetone under the action of an acidic catalyst. The decomposition products are obtained by rectification. Many side reactions occur in the oxidation and decomposition reactions, and the impurities generated by these side reactions bring great difficulties to the purification of phenol. [0003] It is relatively easy to remove the water in phenol, which can be realized by general rectification method. However, it is more difficult to remove organic impurities. With general distillation, only resin-g...

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Problems solved by technology

For example, US 5502259 discloses a method for refining phenol using a zeolite catalyst. The hydroxyacetone in the raw material can be completely removed by using common zeolite molecular sieves (X, Y, ZSM-5, etc.) at 120-250°C, but form The content of benzofuran increases without exception, and the content is above 100ppm, which cannot meet the requirements of high-purity phenol of epoxy resin grade bisphenol A

Recently US7102036B2 discloses a kind of solid superacid SO 4 2- / ZrO 2 / γ-Al 2 o 3 The method for refining phenol, when the raw material contains 200ppm hydroxyacetone and 50ppm mesityl oxide, the reaction temperature is 90-200°C, and the bed volume space velocity is 1-6h-1, and the hydroxyacetone in the product is basically removed , but the content of methyl benzofuran, which is difficult to further remove, reaches 50ppm, and the product phenol cannot reach high-purity grade

CN 1898189A discloses a method for refining phenol by acidic ion-exchange resin at a lower temperature and longer residence time, the method can simultaneously reduce the content of hydroxyacetone and methylbenzofuran in the raw material, and it adopts common ion-exchange resin (Amerlyst A-15, Bayer K2431, etc.) The reaction conditions are 50-100°C, and the weight hourly space velocity (WHSV) is 0.1-5. The disadvantage is that the methylbenzofuran in the product cannot be lower than 5ppm, that is, it cannot reach high-grade purity.

[0011] Refining phenol by two-step solid acid method is a new technology that has appeared recently. For example, US7002048B2 and US7034192B2 disclose a process for refining phenol by two-step method. The first step uses strong acid ion exchange resin AmerlystA-36 to treat crude phenol material at 85 °C In the second step, strong acid ion exchange resin Amerlyst A-36 is used to treat the phenol material in the first step at 134°C, which can reduce the content of methylbenzofuran in the product to below 5ppm. The defect is that the resin will desorb as the operating time increases The ability to remove impurities is reduced, and its lifespan is only 1 to 1.5 years, and it cannot be regenerated

The disadvantage of the two-stage resin method at the same time is that the operating temperature of the first stage is low (85°C). Since the upstream process of phenol production generally uses dehydrogenation and rectification, the crude phenol flowing out of the tower reactor is at about 150°C. If After two stages of resin, the temperature must be lowered to 85°C to pass through the first stage of resin, and then heated to 134°C to pass through the second stage of resin. The whole process requires two unnecessary heat exchange processes.

[0012] RU 2266275C1 also announced a two-step process for refining phenol with solid acid. In the first step, a transition metal catalyst is used to remove impurities such as hydroxyacetone while feeding oxygen. In the second step, X or Y zeolite is used to further The disadvantage of removing methyl benzofuran is that the content of methyl benzofuran in the product is above 50ppm, which is difficult to meet the needs of high-purity phenol

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