CN101250097B - Method for preparing 3,5-dibromine-4-hydroxy benzaldehyde - Google Patents

Abstract

The invention provides a preparation method of 3, 5-dibromo-4-hydroxy benzaldehyde, which uses p-cresol and o-dichlorobenzen as raw materials, processes low-temperature bromination at 32-42DEG C, high-temperature bromination at 145-168DEG C, hydrolysis, dehydration and drying to synthesize 3, 5-dibromo-4-hydroxy benzaldehyde. The inventive method has clear mechanism, simple operation, high product yield and reduced water content, while the HBr gas generated in preparation can be recovered to be reused, thereby reducing production cost, saving energy and protecting environment. The invention is suitable for industrial production.

Description

3, the preparation method of 5-two bromo-4-hydroxy benzaldehydes

Technical field

The present invention relates to a kind ofly 3, the preparation method of 5-two bromo-4-hydroxy benzaldehydes belongs to the ocean field of fine chemical.

Background technology

3,5-two bromo-4-hydroxy benzaldehydes claim two bromals again, are a kind of important medicine, pesticide intermediate.Two bromals are to produce 3,4, the main raw material of 5-TMB and bromoxynil, 3,4,5-TMB (TMB) is applied to the intermediate of synthetic antibacterial drug, Trimpex methoxy benzyl ammonia phonetic (TMP), and cauline leaf was handled the contact killing type weedicide after bromoxynil was widely used as the selectivity bud.

2002 the 2nd phase 36-38 of Qingtao Chemical Engineering College's journal page or leaf, Qingtao Chemical Engineering College's applied chemistry is Cao Wei etc., 3 of report, 4,5-TMB synthesis technique, mention and adopt p-Hydroxybenzaldehyde and bromine effect to generate 3,5-two bromo-4-hydroxy benzaldehydes, wherein concrete step is not discussed in report.

At present, industrial most employing is starting raw material with the p-Hydroxybenzaldehyde, generates 3,5-two bromo-4-hydroxy benzaldehydes with the bromine reaction.Because in recent years, along with developing rapidly of industry such as medicine, agricultural chemicals, spices, domestic p-Hydroxybenzaldehyde demand increases considerably, and the domestic market breach is very big, a large amount of dependence on import; The price of p-Hydroxybenzaldehyde rises steadily, and causes production cost also high.

Summary of the invention

Purpose of the present invention has overcome existing shortcoming in the prior art, provides a kind of 3, the preparation method of 5-two bromo-4-hydroxy benzaldehydes, and it is simple that this method has method, and cost is low, and the productive rate of product is stable, and water content is low.

The technical solution adopted in the present invention by operations such as 32-42 ℃ of low temperature bromination, 145-168 ℃ high temperature bromination, hydrolysis, dehydration and dryings, synthesizes 3,5-two bromo-4-hydroxy benzaldehydes.

Of the present invention 3, the preparation method of 5-two bromo-4-hydroxy benzaldehydes may further comprise the steps:

(1) in bromination reactor, add p-cresol, orthodichlorobenzene respectively, stir fully dissolving, temperature is controlled at 32-42 ℃, and vacuum control drips Br at≤0Mpa ₂, bromination reaction 4-5.5h collects the HBr gas that produces in the reaction process simultaneously, after reaction finishes, and insulation 0.5-2h;

(2) insulation finishes, and is warming up to 145-168 ℃ again, and vacuum control drips Br at≤0Mpa ₂, bromination reaction 5-7.5h collects the HBr gas that produces in the reaction process simultaneously, and after reaction finished, insulation 2-3h is cooled to 120-135 ℃ naturally, gets the bromination feed liquid, and was standby;

(3) in the cooling of bromination feed liquid, in hydrolysis reactor, add HBr acid, reclaim orthodichlorobenzene, stir, stand-by;

(4) the bromination feed liquid that then step (2) is prepared changes in step (3) hydrolysis reactor, and temperature is controlled at 85-120 ℃, stirring and refluxing reaction 4-5h;

(5) stop to stir, be cooled to 90-110 ℃ after logical water coolant, spontaneous nucleation is cooled to 45-55 ℃, filters dehydration, drying promptly gets 3,5-two bromo-4-hydroxy benzaldehydes.

Described p-cresol add-on is: 200-250g;

The mol ratio of the orthodichlorobenzene consumption described in the step (1) is 0.25-0.5 a times of p-cresol;

Br described in the step (1) ₂The mol ratio of consumption is 2-3.5 a times of p-cresol;

Br described in the step (2) ₂The mol ratio of consumption is 2-3.5 a times of p-cresol;

The concentration of the HBr acid described in the step (3) is 10-20%;

The consumption of the HBr acid described in the step (3) is 600-820g;

The HBr gas that described reaction process produces, water and alkali lye absorb.

Reaction medium by selecting to suit, optimize reaction process condition, to improve the quality of products, reaction yield, to reduce production costs be very important.Among the preparation method of the present invention, by accurate, the appropriate control to low temperature bromination, high temperature bromination, bromination time, hydrolysis temperature and time and pressure values, dehydration, drying are to avoid the key that water content is higher, productive rate is low in technical process.To improving the utilization ratio of reactant, reduced water content, improved product performance and played a decisive role.In the reaction process, because impurity is few, orthodichlorobenzene can repeat to recycle again simultaneously, and the bromize hydrogen gas that is produced in the bromination reaction process recycles and reuses equally, economizes in raw materials, and reduces production costs.

Beneficial effect: present method mechanism is clear, pass through 32-42 ℃ of low temperature bromination, 145-168 ℃ high temperature bromination in the preparation process, temperature controlling, improve the productive rate of product, effectively reduce water content, and simple to operate, the HBr gas and the orthodichlorobenzene that produce in the production process are recyclable, utilize once more, reduced cost, environmental protection and energy saving.

Embodiment

The invention will be further described below in conjunction with embodiment, but embodiments of the present invention are not limited thereto.

Embodiment 1

(1) in the 1000ml bromination reactor, add p-cresol 200g (1.85mol) and orthodichlorobenzene 92.5g (0.74mol) respectively, stir fully dissolving, temperature is controlled at 40 ℃, and vacuum control drips Br at≤0Mpa ₂563g (3.52mol), bromination reaction 5h collects the HBr gas that produces in the reaction process simultaneously, after reaction finishes, insulation 1h;

(2) insulation finishes, and slowly is warming up to 140 ℃ again, and vacuum control is at≤0Mpa, Dropwise 5 60g (3.5mol) Br ₂, bromination reaction 6h collects the HBr gas that produces in the reaction process simultaneously, and after reaction finished, insulation 2h is cooled to 125 ℃ naturally, gets the bromination feed liquid, and was standby;

(3) in the cooling of bromination feed liquid, in the 2000ml hydrolysis reactor, adding concentration is 15% HBr acid 700g (1.30mol), reclaims orthodichlorobenzene;

(4) the bromination feed liquid that then step (2) is prepared changes in step (3) hydrolysis reactor, slowly is warming up to 110 ℃, backflow 4.5h;

(5) stop to stir, backflow finishes, be cooled to 105 ℃ after logical water coolant, spontaneous nucleation is cooled to 50 ℃ and filters, dries, and obtains outward appearance and is light yellow 3,5-two bromo-4-hydroxy benzaldehydes.

After testing: it is 95% that two bromals contain pure, yield 84%, moisture :≤0.3%.

Embodiment 2

(1) in the 1000ml bromination reactor, add p-cresol 250g (2.31mol) and orthodichlorobenzene 100g (0.8mol) respectively, stir fully dissolving, temperature is controlled at 38 ℃, and vacuum control drips Br at≤0Mpa ₂720g (4.5mol), bromination reaction 5h collects the HBr gas that produces in the reaction process simultaneously, after reaction finishes, insulation 1h;

(2) insulation finishes, and slowly is warming up to 148 ℃ again, and vacuum control drips 715g (4.47mol) Br at≤0Mpa ₂, bromination reaction 6.5h collects the HBr gas that produces in the reaction process simultaneously, and after reaction finished, insulation 2h is cooled to 125 ℃ naturally, gets the bromination feed liquid, and was standby;

(3) in the cooling of bromination feed liquid, in the 2000ml hydrolysis reactor, adding concentration is 15% HBr acid 750g (1.39mol), reclaims orthodichlorobenzene;

(4) the bromination feed liquid that then step (2) is prepared changes in step (3) hydrolysis reactor, slowly is warming up to 110 ℃, backflow 4.5h;

(5) stop to stir, reflux and finish, be cooled to 100 ℃ after logical water coolant, spontaneous nucleation is cooled to 50 ℃ and filters, dries, and obtains outward appearance and is light grey 3,5-two bromo-4-hydroxy benzaldehydes.

After testing: it is 94.5% that two bromals contain pure, yield 81.5%, moisture :≤0.3%.

Embodiment 3

(1) in the 1000ml bromination reactor, add p-cresol 210g (1.94mol) and orthodichlorobenzene 92.5g (0.74mol) respectively, stir fully dissolving, temperature is controlled at 42 ℃, and vacuum control drips Br at≤0Mpa ₂600g (3.75mol), bromination reaction 5h collects the HBr gas that produces in the reaction process simultaneously, after reaction finishes, insulation 1h;

(2) insulation finishes, and slowly is warming up to 155 ℃ again, and vacuum control drips 600g (3.75mol) Br at≤0Mpa ₂, bromination reaction 7h collects the HBr gas that produces in the reaction process simultaneously, and after reaction finished, insulation 2h is cooled to 125 ℃ naturally, gets the bromination feed liquid, and was standby;

(3) in the cooling of bromination feed liquid, in the 2000ml hydrolysis reactor, add 18% HBr acid 700g (1.56mol) recovery orthodichlorobenzene;

(4) the bromination feed liquid that then step (2) is prepared changes in step (3) hydrolysis reactor, slowly is warming up to 115 ℃, backflow 4.5h;

(5) stop to stir, reflux and finish, be cooled to 110 ℃ after logical water coolant, spontaneous nucleation is cooled to 50 ℃ and filters, dries, and obtains outward appearance and is light yellow 3,5-two bromo-4-hydroxy benzaldehydes.

After testing: it is 94% that two bromals contain pure, yield 82.5%, moisture :≤0.3%.

Claims (1)

1. one kind 3, the preparation method of 5-two bromo-4-hydroxy benzaldehydes may further comprise the steps:

(1) in bromination reactor, add p-cresol, orthodichlorobenzene respectively, wherein said p-cresol add-on weight part is: 200-250, the mol ratio of described orthodichlorobenzene consumption is 0.25-0.5 a times of p-cresol, stir fully dissolving, temperature is controlled at 32-42 ℃, and vacuum control drips Br at≤0Mpa ₂, bromination reaction 4-5.5h collects the HBr gas that produces in the reaction process, described Br simultaneously ₂The mol ratio of consumption is 2-3.5 a times of p-cresol, after reaction finishes, and insulation 0.5-2h;

(2) insulation finishes, and is warming up to 145-168 ℃ again, and vacuum control drips Br at≤0Mpa ₂, described Br ₂The mol ratio of consumption is 2-3.5 a times of p-cresol, and bromination reaction 5-7.5h collects the HBr gas that produces in the reaction process simultaneously, and after reaction finished, insulation 2-3h is cooled to 120-135 ℃ naturally, gets the bromination feed liquid, and was standby;

(3) in the cooling of bromination feed liquid, in hydrolysis reactor, add HBr acid, the concentration of described HBr acid is 10-20%, the consumption weight part of described HBr acid is 600-820, reclaims orthodichlorobenzene, stirs, and is stand-by;

(4) the bromination feed liquid that then step (2) is prepared changes in step (3) hydrolysis reactor, and temperature is controlled at 85-120 ℃, stirring and refluxing reaction 4-5h;

(5) stop to stir, be cooled to 90-110 ℃ after logical water coolant, spontaneous nucleation is cooled to 45-55 ℃, filters dehydration, drying promptly gets 3,5-two bromo-4-hydroxy benzaldehydes.