Preparation method of o-dihydroxybenzene

Abstract

The invention provides a preparation method of o-dihydroxybenzene. The preparation method comprises the following steps: (1) under a reaction condition that can convert cyclohexene into 1,2-cyclohexanediol through oxidation, contacting cyclohexene and an oxidant with a catalyst so as to obtain reaction fluid containing 1,2-cyclohexanediol, removing the negative ions and positive ions in the reaction fluid so as to obtain dehydrogenation stock solution; (2) under a liquid phase catalytic dehydrogenation condition, contacting the dehydrogenation stock solution with a dehydrogenation catalyst. In this preparation method, 1,2-cyclohexanediol does not need to be removed before the hydrogenation preparation of o-dihydroxybenzene, so the preparation method has the advantages of simple technology, reduced energy consumption, and high o-dihydroxybenzene yield, and has a very high industrial application value.

Description

technical field [0001] The invention relates to a method for preparing catechol. Background technique [0002] Catechol, also known as catechol, is an organic phenol commonly found in fruits and vegetables, and is a component of plant tannins. Catechol is an important chemical intermediate, which can be used in the manufacture of rubber hardeners, electroplating additives, skin antiseptics, hair dyes, and photographic developers. [0003] CN1160703A discloses a production method of catechol, which is to oxidize cyclohexene with hydrogen peroxide in the presence of formic acid, then directly add alkali to neutralize, hydrolyze into 1,2-cyclohexanediol, and then extract with ethyl acetate , and then evaporate the solvent to obtain 1,2-cyclohexanediol, and then pass through the vaporized and superheated 1,2-cyclohexanediol aqueous solution vapor on the fixed bed equipped with Ni / diatomaceous earth catalyst, and carry out catalytic dehydrogenation to obtain To obtain catechol,...

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Problems solved by technology

[0006] Meanwhile, the method for preparing catechol with cyclohexene as a raw material first prepares 1,2-cyclohexanediol by oxidizing cyclohexene, then obtains 1,2-cyclohexanediol through steps such as extraction and distillation, and then Dehydrogenate 1,2-cyclohexanediol to obtain catechol, and prepare catechol according to this method. Since the amount of solvent and the like is very large in the industrial application process, the energy consumption of extraction or distillation is very high. High, thereby greatly reducing its industrial application value, and the inventors of the present invention try to imagine whether it is not possible to separate, and directly dehydrogenate the liquid phase product mainly comprising 1,2-cyclohexanediol obtained by oxidizing cyclohexene The preparation of catechol can greatly reduce energy consumption and greatly save operating procedures, and it is found that the liquid phase product obtained by oxidative dehydrogenation contains a large amount of anions and The cation affects the dehydrogenation activity of the subsequent dehydrogenation catalyst, resulting in a very low efficiency of the dehydrogenation process, making it impossible to efficiently prepare catechol according to this method; on this basis, the inventors of the present invention proposed that the liquid phase The anions and cations brought by the oxidation catalyst in the product can avoid affecting the activity of the dehydrogenation catalyst in the subsequent dehydrogenation process. At the same time, the reactants in the liquid phase reaction are not easy to coke on the catalyst, which greatly prolongs the life of the catalyst, so that catechol can be efficiently prepared, and it overcomes the easy coking of catechol and the easy coking of the catalyst. Defects that cannot be continuously and effectively mass-produced due to inactivation

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