Catalyst for synthesizing p-hydroxybenzonitrile (2-hydroxybenzonitrile) and preparation method of catalyst

Abstract

The invention discloses a catalyst for synthesizing p-hydroxybenzonitrile (2-hydroxybenzonitrile) and a preparation method of the catalyst. Phosphoric acid, copper nitrate, stannous oxalate and ammonium molybdate are dissolved in deionized water, an impregnation liquid is prepared, and a bar-shaped Silicalite-1 molecular sieve is impregnated in the impregnation liquid for 12-24 h at the room temperature; the impregnated molecular sieve is dried in a drying oven at 80-120 DEG C for 6-24 h and roasted in a muffle furnace at 450-600 DEG C for 4-12 h, and the catalyst is obtained. The catalyst is prepared from active components in terms of the mass percentage of the carrier as follows: 0.5-15% of P2O5, 0.1%-3.0% of CuO, 0.5%-4.5% of SnO and 0.2%-2% of MoO3. The catalyst is prepared with a conventional impregnation method, and the technological process is simple and easy to operate; the all-silicon molecular sieve is used as an active carrier and has a synergistic effect with all active oxide components, and the prepared catalyst is applicable to the continuous production process of p-hydroxybenzonitrile (2-hydroxybenzonitrile) by use of a fixed bed reactor and has the advantages of high raw material conversion rate, high product selectivity and long service life in the p-hydroxybenzonitrile (2-hydroxybenzonitrile) synthesis process.

Description

technical field [0001] The invention relates to a preparation method of a catalyst, in particular to a catalyst for synthesizing p-(o)hydroxybenzonitrile and a preparation method thereof, belonging to the technical field of chemical industry. Background technique [0002] p-Hydroxybenzonitrile, also known as p-cyanophenol, p-hydroxybenzonitrile, etc., is an extremely important fine organic chemical raw material and intermediate, widely used in the synthesis of various medicines, spices, pesticides, liquid crystal materials and buffers Agents, etc., especially as pesticide intermediates, can be used to synthesize a variety of pesticides such as "fenonitrile", "benzonilphos", "bromoxynil", "hydroxychlorenil" and "chlorothalonil". With the development of my country's agricultural modernization, the demand for pesticides has increased significantly, and the demand for p-hydroxybenzonitrile has also increased significantly. O-hydroxybenzonitrile, also known as salicylonitrile, c...

AI Technical Summary

Problems solved by technology

[0003] There are many synthetic methods of hydroxybenzonitrile, which can be divided into hydroxybenzoic acid dehydration ammoniation method, hydroxybenzaldehyde ammoniation method, diazonium salt method, p-cresol method and p-cresol sodium method according to different raw materials: Benzoic acid dehydration ammonification method usually obtains p-hydroxybenzonitrile by ammoxidation reaction of p-cresol in a fluidized bed. Although the process adopts a fluidized bed continuous reaction, under the reaction conditions, a higher The reaction temperature obtains a lower p-hydroxybenzonitrile yield, and the yield is only 50 to 65%, and the unsafety of the reaction system is increased due to the existence of oxygen in the reaction process

Hydroxybenzaldehyde ammonification method adopts p-hydroxybenzaldehyde and hydroxylamine hydrochloride to prepare p-hydroxybenzonitrile under the effect of tungsten catalyst, but in this reaction process, the catalyst consumption is too large, which is about 9% of the raw material p-hydroxybenzaldehyde amount times, and the reaction process is slow; at the same time, the most important thing is that the process adopts the batch reaction form, which further restricts the large-scale production requirements

The diazonium salt method, the p-cresol method and the sodium p-cresol method, etc. basically adopt a batch reaction, which is not suitable for large-scale continuous production, and the reaction pressure is also high, which increases the investment in equipment; in addition, the reaction There are many steps and complicated operation process, which limits the large-scale production of p-hydroxybenzonitrile

[0004] Therefore, in the process of synthesizing p-(o)hydroxybenzonitrile, the continuous production mode that simplifies the reaction steps, reduces the process flow, reduces equipment requirements, and reduces the discharge of three wastes is urgently needed for industrial production; but it limits the success of this continuous production mode The main factor is the lack of a catalyst suitable for this mode with good stability, good selectivity and high yield