Low-capacity solid acid catalyst for hydroxylation of phenol reaction and preparation method thereof

Abstract

The invention discloses a low-capacity solid acid catalyst for hydroxylation of phenol reaction and a preparation method thereof, and belongs to the technical field of solid acid catalysts. According to the technical scheme, a catalyst which has adjustable acidity and high dispersion of active components is prepared by the steps of immersing a carrier in a dilute nitric acid solution containing an active component precursor, an additive precursor and a surface active agent under the vacuum condition, then oscillating and drying at low-temperature water bath, and forging at 400-600 DEG C for 1-3 hours. The method effectively solves the radical problem of the existing hydroxylation of phenol technology: temperature runaway enables the phenol conversion rate to achieve 67.09%, the selectivity of hydroquinone to achieve 99.19% and the tar content to be lowered to 0.91%, and favorable effects are obtained.

Description

technical field [0001] The invention belongs to the technical field of solid acid catalysts, and specifically relates to a method for preparing a low-load solid acid catalyst specially used for the hydroxylation of phenol to prepare hydroquinone. The purpose of the invention is to provide a method that can inhibit the hydroxylation reaction The preparation process of a new catalyst that is violent, exothermic and overheating, reduces the tar content, and increases the yield of hydroquinone. Background technique [0002] Hydroquinone (mainly catechol and hydroquinone) is a very important chemical raw material, widely used in pesticides, medicines, spices, and bleaching industries. , It is also far from meeting the needs of domestic actual production. From this we can see that the development and production of hydroquinone has broad market prospects in my country. [0003] The industrialized technology of quinone has been developed to the present and has experienced the produc...

AI Technical Summary

Problems solved by technology

[0002] Hydroquinone (mainly catechol and hydroquinone) is a very important chemical raw material, widely used in pesticides, medicines, spices, and bleaching industries. , and it is far from meeting the needs of domestic actual production. It can be seen that the development and production of hydroquinone has broad market prospects in my country

[0003] The industrialized technology of quinone has been developed to the present and has experienced the production methods of unit production and co-production. Among them, the main technologies for producing quinone are o-chlorophenol hydrolysis and aniline oxidation, two traditional production processes. Among these two processes Using a mass fraction of 75% NaOH and 50% H 2 SO 4 , the requirements for the material of the reactor are relatively high; and a large amount of acid and alkali are used, resulting in a lot of three wastes and serious environmental pollution

[0004] The method of co-production of quinone is mainly the green process-hydrogen peroxide method. This production technology mainly includes the Rhone-Poulenc method in France, the Ube method in Japan, the Brichima method in Italy and the Enichem method. Among them: the Rhone-Poulenc method (in the form of HClO 4 as catalyst, H 3 PO 4 as cocatalyst), Ube method (with sulfuric acid as catalyst), Brichima method (Fe 2+ / Co 2+ Salt as a catalyst) all have the disadvantages that the homogeneous catalytic reaction itself is difficult to overcome: the separation and recovery of the catalyst is difficult, the equipment is severely corroded, and the process is difficult to continuously produce

Thirdly, the Rhone-Poulenc and Ube methods (reaction temperature: 80-100°C) both use strong acid as a catalyst. The hydrogen peroxide with a concentration of 60% has a low safety factor in the production process, and the effective utilization rate of hydrogen peroxide is low

The Enichem method uses TS molecular sieve as a catalyst, which avoids the defects of the above-mentioned process, but the preparation process of TS molecular sieve catalyst is complicated, the price is particularly expensive, and the introduction cost of TS-1 molecular sieve preparation technology is astonishing, thus limiting its industrial application

[0005] In order to improve the production process of quinone, many researchers are constantly developing new processes. Among them, the iron-based composite oxide solid acid catalyst has become a hot catalyst for diphenol research because of its high catalytic activity and low price. At present, many domestic manufacturers Units are engaged in research in this area. Patent CN1134313 discloses a catalyst for phenol hydroxylation: AxByOz, wherein A is a metal or a rare earth metal, which makes the price of the catalyst more expensive. In addition, this series of catalysts are used for hydroxylation During the reaction, the reaction time is long, the temperature is high, the selectivity of phenol is poor, and the catalyst activity is low

Patent CN98100892.5 discloses a solid acid catalyst for the hydroxylation of phenol to quinone, which is defined as: A a B b C c D. d o x / carrier, where A can choose one or both from Fe or Co, preferably Fe, its disadvantage is the precursor of A Fe (NO 3 ) 3 The mass ratio of the loading amount to the carrier>108.25%, the active component Fe 2 o 3 Although it shows a weak diffuse distribution, its derivative peaks can still be seen, which reduces its utilization rate, and the catalyst is highly acidic and unevenly distributed, resulting in a severe hydroxylation reaction, and the released heat is used by side reactions, resulting in a large amount of tar, the product poor selectivity

Patent CN101480613B discloses a catalyst capable of carrying out hydroxylation reaction at normal temperature (20-40°C): A m B n Fe x SiO y , the catalyst improves the selectivity of hydroquinone, but the conversion rate of phenol of this series of catalysts can only be maintained at 16.08%-27.82%, and the activity of the catalyst is low

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