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A kind of preparation method of p-cyanobenzoic acid

A technology of cyanobenzoic acid and chloromethyl benzonitrile is applied in the preparation of carboxylic acid nitrile, the preparation of organic compounds, chemical instruments and methods, etc. problems, to achieve the effect of improving product purity and yield, simple reaction steps, and low reaction energy consumption

Active Publication Date: 2019-08-06
DALIAN QIKAI MEDICAL TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] First, use 4-chloromethylbenzonitrile as raw material and concentrated nitric acid as an oxidant to synthesize p-cyanobenzoic acid. Although the synthetic route is simple, there are too many by-products, serious pollution, and the three wastes are not easy to handle, so it is not suitable for industrial applications.
[0005] Second, p-methanol benzoic acid is used as raw material to synthesize p-cyanobenzoic acid, but in this synthesis method, formic acid is used, which is highly corrosive and not suitable for working operations
[0006] Third, the ammoxidation method is used to prepare synthetic p-cyanobenzoic acid, but the biggest problem with this method is that high pressure and temperature are required in the reaction process, which will increase the equipment requirements for industrial production, and is not suitable for large-scale industrial production
[0007] In summary, the traditional synthetic method has too many by-products in the reaction process, the use of reagents is highly corrosive, and high temperature and high pressure are limiting conditions. It can be seen that the existing method cannot meet the needs of modern production of p-cyanobenzoic acid.

Method used

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  • A kind of preparation method of p-cyanobenzoic acid

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Put 138g of potassium carbonate, 151.5g of 4-chloromethylbenzonitrile and 2300g of water into a 3000mL four-necked bottle. Heat to 80°C, react for 10 hours, take a sample for HPLC detection, confirm that the hydrolysis reaction of 4-chloromethylbenzonitrile is complete, add dichloromethane to the hydrolysis reaction solution and extract (each time 800mL, extract 3 times at room temperature) , the extract was distilled off to remove the extraction solvent to obtain 128 g of 4-cyanobenzyl alcohol with a purity of 96-98% and a yield of 96.2%.

[0033] Put 128g of 4-cyanobenzyl alcohol, 6.2g of methyl trioctyl ammonium bisulfate, 4.6g of sodium tungstate dihydrate, 4g of vanadyl sulfate, 4g of sodium chloride, and 500g of water into a four-necked bottle. Heated the bath to raise the temperature to 90°C, and added 400 g of 30% hydrogen peroxide dropwise to the kettle. Sampling was carried out for HPLC detection. When 4-cyanobenzyl alcohol disappeared, the reaction was compl...

Embodiment 2

[0035] Add 10g of potassium bicarbonate, 15.1g of 4-chloromethylbenzonitrile and 150g of water into a 250mL four-necked bottle, raise the temperature to 80°C under full stirring, and react for 10 hours. After HPLC detection, it is confirmed that the hydrolysis reaction of the raw materials is complete, and the reaction Chloroform was added to the solution for partial extraction (100 mL each time, extracted 3 times at room temperature), and the extract was distilled to remove the extraction solvent to obtain a total of 12.6 g of intermediate 4-cyanobenzyl alcohol, with a purity of 93%-95%. was 94.7%.

[0036] Put 12.6g of 4-cyanobenzyl alcohol, 0.62g of methyl trioctyl ammonium chloride, 0.46g of sodium tungstate dihydrate, 0.4g of sodium sulfate, 0.4g of vanadyl sulfate, tert-butanol into a 500mL four-necked bottle 50g, raise the temperature of the kettle to 80°C, slowly add 200g of tert-butyl hydroperoxide dropwise with a micro-dropping funnel, and perform HPLC detection by s...

Embodiment 3

[0038] Add 10 g of potassium hydroxide, 15.1 g of 4-chloromethylbenzonitrile and 120 g of water into a 250 mL four-necked bottle to carry out the hydrolysis reaction of the raw materials. Under mechanical stirring, it was heated to reflux (82° C.), and detected by HPLC, it can be seen that the raw materials had been completely reacted after 10 hours of reaction. At this point, petroleum ether was added for partial extraction (80 mL each time, extracted 3 times at normal temperature), and the extract was distilled to remove the extraction solvent to obtain the intermediate 4-cyanobenzyl alcohol, a total of 11.4 g, with a purity of 88-92%. The rate is 85.7%.

[0039] In a 250mL four-necked bottle, add 11.4g of 4-cyanobenzyl alcohol, 0.62g of tetrabutylammonium chloride, 0.46g of sodium tungstate, 0.4g of sodium sulfate, 0.4g of vanadyl sulfate, 60g of sodium hypochlorite, and 50g of ethanol. The temperature was raised to 78°C, and HPLC detection was carried out by sampling. Whe...

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Abstract

The invention discloses a method for preparing p-cyanobenzoic acid. The method comprises the following steps: taking 4-chloromethylbenzonitrile as a raw material and hydrolyzing to obtain 4-cyanobenzyl alcohol as an intermediate product under alkaline conditions, adding a phase transfer catalyst, an activator, an oxidant and a catalyst, and carrying out an oxidation reaction for 4 to 15h at a temperature of 50 to 100 DEG C to obtain a final product. The specific phase transfer catalyst and the catalyst are used and salts are added to be used as the activator of the phase transfer catalyst in the oxidation reaction, so that the oxidation reaction time of the 4-cyanobenzyl alcohol as the intermediate product is shortened to 6 to 10 hours, the yield of the 4-chloromethylbenzonitrile as the final product reaches to 86.4% or more, and the purity reaches to 98.6% or more. The method is safe, non-polluting, simple to operate and high in purity, and is a new method suitable for green chemistryapplication.

Description

technical field [0001] The invention relates to a preparation method of p-cyanobenzoic acid, which belongs to the field of chemical production technology. Background technique [0002] p-cyanobenzoic acid is a white leafy crystal with the molecular formula C 8 h 5 NO 2 , the molecular weight is 147.13, the melting point is 217-222°C, partially miscible with water, soluble in alcohol, ether, hot water and glacial acetic acid. It can generate terephthalic acid with hot alkali. As an intermediate of hemostatic aromatic acid, p-cyanobenzoic acid is used in organic synthesis, liquid crystal polymer synthesis, pharmaceutical intermediates, etc. [0003] At present, the production methods of p-cyanobenzoic acid mainly contain the following types: [0004] First, 4-chloromethylbenzonitrile is used as raw material, and concentrated nitric acid is used as an oxidant to synthesize p-cyanobenzoic acid. Although the synthetic route is simple, there are too many by-products, serious ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C253/30C07C255/57
Inventor 赵胜楠姜殿平张洪学张忠
Owner DALIAN QIKAI MEDICAL TECH
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