Preparation method for supported solid-acid catalyst for synthesising 2-isonaphthol via one-step hydroxylation of naphthalene

Abstract

The invention discloses a preparation method for a supported solid-acid catalyst for synthesising 2-isonaphthol via the one-step hydroxylation of naphthalene, belonging to the technical field of supported solid-acid catalysts, wherein via the technical scheme of soaking a supporter in a solution containing an auxiliary constituent precursor in a vacuum condition, vibrating and drying in a low-temperature water bath, and calcining for 1-3 hours at 400-600 DEG C at first, and then soaking the calcined powder in the solution containing an auxiliary constituent precursor in a vacuum condition, vibrating and drying in the low-temperature water bath, and baking in an airflow at 110-300 DEG C, a solid-acid catalyst which is adjustable in surface acidity and high in the dispersibility of active constituents is prepared. With the adoption of the method, the various problems existing in the prior art are effectively solved, the conversion rate of naphthalene and the selectivity of 2-isonaphthol are greatly increased, and good effects are obtained.

Description

technical field [0001] The invention belongs to the technical field of supported solid acid catalysts, is applied to the hydroxylation reaction of polycyclic aromatic hydrocarbons (PAHs), and specifically relates to a preparation method of a solid acid catalyst exclusively used for one-step hydroxylation of naphthalene to synthesize 2-naphthol. Background technique [0002] 2-Naphthol, also known as β-naphthol, ethyl naphthol or 2-hydroxynaphthalene, is an important organic chemical raw material and synthetic intermediate. There are more than 130 kinds of dyes and pigments directly synthesized from it, and more than 20 dye intermediates indivual. It is also widely used in medicine, pesticides, rubber additives, spices, leather tanning, textile printing and dyeing additives, and mineral processing agents. [0003] The traditional production techniques of 2-naphthol are: 1. Sulfonated alkali fusion method. The sulfonation alkali fusion method is the main method of industrial...

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Problems solved by technology

[0005] In the one-step hydroxylation of naphthalene to synthesize 2-naphthol, there are mainly acid catalysis and metal oxide catalysis, among which: acid catalysis mainly uses liquid superacid HF as the catalyst, which makes the process have a homogeneous catalytic reaction itself Difficult to overcome shortcomings: poor product selectivity, difficulty in catalyst separation and recovery, serious corrosion of equipment, difficult continuous production of the process

In addition, the acidity of the catalyst is too strong, so that the generated naphthol is further hydroxylated to generate polyhydroxynaphthalene, and the product selectivity is poor

[0006] The metal oxide catalysis method uses solid acid as a catalyst for the hydroxylation reaction. For example, in the literature Yang Huiqiong "Jiangsu Chemical Industry", the study of spinel-type magnesium ferrite as a catalyst for the hydroxylation of naphthalene is introduced. The best process conditions reported in it However, the catalyst activity is poor, and the highest total yield of naphthol is only 12.7%. In the document Tang Jiyong "In Chemical Production and Technology", a kind of active component Fe was proposed. 2 o 3 Loaded on high specific surface area carrier γ-Al 2 o 3 The preparation method, compared with the pure metal oxide catalyst, the active component Fe 2 o 3 The utilization rate has increased, but m(Fe 2 o 3 ) / m(γ-Al 2 o 3 )>250%, the dispersion of active components is poor, and the utilization rate of atoms is still relatively low. In addition, Fe 2 o 3 As an active component of a naphthalene hydroxylation catalyst, the generated naphthol is easily further hydroxylated to generate polyhydroxynaphthalene, and the product selectivity is poor

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