Ultrasonic-assisted rapid synthesis of salicylaldehyde azine

Abstract

The invention relates to a method for rapidly synthesizing salicylaldehyde azine by ultrasonic-assisted method. Salicylaldehyde is put into a round-bottom flask, and 10% ammonia solution, 5% hydrogen peroxide solution and a certain mass of disodium hydrogen phosphate powder are added into the flask; the round-bottom flask is placed in an ice-water bath of an ultrasonic reactor, and the ultrasonic frequency is set to 60-65kHZ, and the power is 400W, and the ultrasonic-assisted reaction is performed for 2-3h; the reacted material is filtered, and the obtained filter residue is the crude salicylaldehyde azine; the crude salicylaldehyde azine is washed and filtered 2-3 times, and the finished product high-purity salicylaldehyde azine is obtained after drying. The process steps of the invention are simple, the operation is convenient, the reaction conditions are mild, the time is short, the efficiency is high, and the molar yield of the target product salicylaldehyde azine can reach more than 88%, which solves the defects of the existing synthesis method, such as the use of toxic raw materials, long synthesis time, high-pressure equipment, complex process, and low yield of salicylaldehyde azine.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of organic compounds, and in particular to a method for rapidly synthesizing salicylaldehyde azine with the assistance of ultrasound. Background Art

[0002] Salicylaldehyde azine is a yellow powder and is insoluble in water. Its molecular formula is C 14 H 12 N2O2, molecular weight 240.26, density 1.17 g / cm 3 , boiling point 399.1℃ at 760mmHg, flash point 256.1℃, salicylaldehyde azine and its derivatives have good optical properties.

[0003] Salicylaldehyde azine and its derivatives have good biological activity and optical properties, and are therefore widely studied and applied in the fields of medicine and materials. In the field of medicine, Ding Guohua et al. mentioned in the invention patent of a salicylaldehyde azine Schiff base transition metal complex and its application that the salicylaldehyde azine Schiff base transition metal complex has antibacterial effects on a variety of bacteria. In the field of optics, salicylaldehyde azine and its derivatives are widely used in the detection of microscopic substances, such as p-nitrosalicylic aldehyde azine can be used as a sensor in ultraviolet spectrophotometry, and has the ability to recognize eight different anions. For another example, salicylaldehyde azine can be used as a dye and is widely used in protein fluorescence detection. In addition, salicylaldehyde azine derivatives such as p-sulfonic acid azo salicylaldehyde azine, terephthalaldehyde and salicylaldehyde hydrazone have been studied or used as new fluorescent probes in multiple medical fields.

[0004] At present, there are few reports on the synthesis methods of salicylaldehyde azine and its derivatives. The common synthesis methods are as follows:

[0005] (1) Sodium hypochlorite, salicylaldehyde, and ammonia are introduced simultaneously and continuously into the same reactor in a molar ratio of 1:2:20, and reacted at 35°C and 200 kPa to obtain salicylaldehyde azine. Although this method can produce the product in one step, the excessive ammonia needs to be condensed and recovered by distillation before it can be reused, which is cumbersome.

[0006] (2) Salicylaldehyde and hydrazine hydrate are reacted at a molar ratio of 2:1 at room temperature to obtain salicylaldehyde azine. Although this method is simple to operate, hydrazine hydrate is highly toxic and requires strict protective measures during operation, which is not friendly to the experimenter.

[0007] Therefore, it is necessary to study and design a synthesis method of salicylaldehyde azine so that it can quickly, conveniently, efficiently and safely complete the preparation of salicylaldehyde azine, in order to reduce the production cost of salicylaldehyde azine and expand its application range. Summary of the invention

[0008] The purpose of the present invention is to provide a method for rapidly synthesizing salicylaldehyde azine by ultrasound-assisted method. Salicylaldehyde, ammonia water and hydrogen peroxide are used as raw materials, disodium hydrogen phosphate is used as a catalyst, and an ultrasonic radiation-assisted reaction mode is adopted to rapidly and efficiently synthesize salicylaldehyde azine, thereby solving the defects of the prior art synthesis method, such as the use of toxic raw materials, long synthesis time, the need for high-pressure equipment, complex process, and low yield of salicylaldehyde azine.

[0009] The present invention is specifically implemented by the following technical scheme. According to the method proposed by the present invention, an ultrasonic-assisted rapid synthesis method of salicylaldehyde azine comprises the following steps:

[0010] (1) taking a certain amount of salicylaldehyde in a round-bottom flask, adding a certain amount of 10% by mass ammonia solution, a 5% by mass hydrogen peroxide solution and a certain amount of disodium hydrogen phosphate powder into the round-bottom flask;

[0011] (2) Place the round-bottom flask containing the reaction materials in step (1) in an ice-water bath of an ultrasonic reactor, set the ultrasonic frequency to 60-65 kHz, the power to 400 W, and use ultrasonic-assisted reaction for 2-3 hours;

[0012] (3) After the reaction is completed, the reacted material is filtered, and the filter residue obtained is the crude product salicylaldehyde azine;

[0013] (4) The crude salicylaldehyde azine obtained in step (3) is washed with water and filtered repeatedly for 2 to 3 times, and the resulting crystals are dried to obtain the finished product of high-purity salicylaldehyde azine.

[0014] In the aforementioned ultrasonic-assisted rapid synthesis of salicylaldehyde azine, in step (1), the molar ratio of NH3 in ammonia water to salicylaldehyde is (2-3):1; the molar ratio of hydrogen peroxide to salicylaldehyde is (0.5-0.6):1; the molar ratio of disodium hydrogen phosphate to salicylaldehyde is (0.1-0.2):1. When adding the hydrogen peroxide solution, it should be slowly poured into the flask along the container wall.

[0015] In the aforementioned ultrasound-assisted rapid synthesis method of salicylaldehyde azine, in step (2), the temperature of the ice water bath is 0-4°C.

[0016] In the aforementioned method for rapid synthesis of salicylaldehyde azine with the assistance of ultrasound, in step (4), the crystals are dried in an oven at about 37° C. under normal pressure.

[0017] The above-mentioned method for rapid synthesis of salicylaldehyde azine with the assistance of ultrasonic wave, the molar yield of the high-purity salicylaldehyde azine finally prepared is 88.9-93.1% compared with salicylaldehyde.

[0018] Compared with the prior art, the present invention has obvious advantages and beneficial effects. By means of the above technical solution, the present invention can achieve considerable technical progress and practicality, and has a wide range of utilization value, and has at least the following advantages:

[0019] (1) The process steps of the present invention are simple, the operation is simple, the reaction conditions are mild, the time is short, the efficiency is high, and there is no pollution to the environment. Compared with the traditional process method for synthesizing salicylaldehyde azine, the present invention uses salicylaldehyde, ammonia water and hydrogen peroxide as raw materials, disodium hydrogen phosphate as catalyst, and under the action of ultrasound, the reactants and the catalyst are evenly dispersed, the catalyst is fully in contact with the reactants, the contact area is increased, the catalytic effect is enhanced, the activation energy of the reaction is reduced, the reaction can be carried out efficiently at a lower temperature, and the target product is synthesized in one step.

[0020] (2) The present invention adopts the method of ultrasonic radiation-assisted reaction in the synthesis process. Under a specific ultrasonic frequency and power, ultrasonic vibration is used to make the molecular contact of the raw materials more complete and uniform, the contact area between the raw materials is larger, the reaction and bonding are faster, more complete and thorough, and the conversion rate of the target product is higher. According to experimental determination, the molar yield of the target compound salicylaldehyde azine can reach more than 88%.

[0021] (3) The present invention proposes a new process for preparing salicylaldehyde azine, simplifies the process steps for preparing salicylaldehyde azine, optimizes the preparation conditions, and uses non-toxic, easily available, green, environmentally friendly, low-cost, and harmless to the human body raw materials. Compared with the prior art, the present invention greatly shortens the reaction time, does not require complex equipment, improves the reaction efficiency and the purity and yield of the finished compound, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a single crystal XRD pattern of the finished product salicylaldehyde azine prepared in Example 1 of the present invention;

[0023] Figure 2 It is the diffraction peak diagram of the finished product salicylaldehyde azine prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] The present invention provides a method for rapid synthesis of salicylaldehyde azine with ultrasound assistance, using salicylaldehyde, ammonia water and hydrogen peroxide solution as raw materials, disodium hydrogen phosphate as a catalyst, and using ultrasonic wave radiation to assist the reaction, in an ice water bath, to achieve rapid and efficient preparation of salicylaldehyde azine. The key points of the process method are the material ratio between the reaction raw materials, the setting of ultrasonic radiation frequency parameters, etc. The specific process steps include:

[0026] (1) Take a certain amount of salicylaldehyde in a round-bottom flask, add a certain amount of 10% ammonia solution, 5% hydrogen peroxide solution and a certain amount of disodium hydrogen phosphate powder into the round-bottom flask; when adding the hydrogen peroxide solution, pour it slowly into the flask along the wall of the container.

[0027] (2) Place the round-bottom flask containing the reaction materials and catalyst in step (1) in an ice-water bath of an ultrasonic reactor, set the ultrasonic frequency to 60-65 kHz, the power to 400 W, and use ultrasonic-assisted reaction for 2-3 hours; the reaction equation of this step is:

[0028]

[0029] (3) After the reaction is completed, the reacted material is filtered, and the filter residue is the crude product salicylaldehyde azine;

[0030] (4) The crude salicylaldehyde azine obtained in step (4) is washed with water and filtered 2 to 3 times for purification, and the obtained crystals are dried to obtain the finished product of high-purity salicylaldehyde azine.

[0031] In one application example, the prepared high-purity salicylaldehyde azine can be further processed to prepare fluorescent dyes.

[0032] Furthermore, in step (1), the molar ratio of NH3 in ammonia water to salicylaldehyde is (2-3):1, the molar ratio of hydrogen peroxide to salicylaldehyde is (0.5-0.6):1, and the molar ratio of disodium hydrogen phosphate to salicylaldehyde is (0.1-0.2):1.

[0033] Furthermore, in step (2), the temperature of the ice water bath is 0-4°C.

[0034] Furthermore, step (3) and step (4) should be carried out in a dry environment as much as possible to prevent the generated salicylaldehyde azine from being hydrolyzed and reducing the yield. Step (4) The crystals are dried in an oven at about 37° C. under normal pressure.

[0035] The present invention is described in detail with specific examples below. The experimental methods and detection methods described in the following examples are all conventional methods in the art unless otherwise specified; the experimental process described is carried out under normal temperature and pressure unless otherwise specified; the reagents and materials described can be purchased on the market unless otherwise specified. The calculation formula for the yield (molar yield) of the product high-purity salicylaldehyde azine relative to salicylaldehyde in the example is:

[0036]

[0037] Example 1

[0038] (1) Take a round-bottom flask, accurately take 9.96 ml (0.10 mol) of salicylaldehyde and 1.42 g (0.01 mol) of disodium hydrogen phosphate powder into the round-bottom flask and set aside;

[0039] (2) Accurately measure 3.56 ml (0.20 mol) of 10% ammonia solution and 1.70 ml (0.05 mol) of 5% hydrogen peroxide solution, add them to the round-bottom flask in step (1) in sequence, and mix with salicylaldehyde and disodium hydrogen phosphate;

[0040] (3) placing the round-bottom flask containing the reaction materials and the catalyst in step (2) in an ice-water bath of an ultrasonic reactor, wherein the temperature of the ice-water bath is 0-4°C, the ultrasonic frequency is set to 60 kHz, the power is set to 400 W, and the ultrasonic-assisted reaction is performed for 2 hours; after the reaction is completed, filtering the reacted material, and the filter residue obtained is the crude product salicylaldehyde azine.

[0041] (4) The crude salicylaldehyde azine obtained in step (3) is washed with water and filtered 2 to 3 times for purification. The resulting crystals are dried to obtain a finished product of high-purity salicylaldehyde azine, which is weighed to be 21.36 g after drying. The yield is calculated based on salicylaldehyde. The molar yield of the product salicylaldehyde azine is 88.9%.

[0042] The prepared high-purity salicylaldehyde azine was subjected to elemental analysis using a Perkin-Elmer 1400C elemental analyzer. The data obtained were: C: 70.08% (theoretical value: 69.99%), H: 4.95% (theoretical value: 5.0%), N: 11.66% (theoretical value: 11.71%), O: 13.32% (theoretical value: 13.26%). The analytical values ​​of the product were basically consistent with the theoretical values.

[0043] The high-purity salicylaldehyde azine prepared in this example was subjected to single crystal X-ray diffraction analysis and detection to obtain a single crystal XRD pattern. The single crystal XRD pattern and diffraction peak pattern of the sample were obtained by using Mercury software. Figure 1 and Figure 2 shown.

[0044] Example 2

[0045] (1) Take a round-bottom flask, accurately take 9.96 ml (0.10 mol) of salicylaldehyde and 2.84 g (0.02 mol) of disodium hydrogen phosphate powder into the round-bottom flask and set aside;

[0046] (2) Accurately measure 5.34 ml (0.30 mol) of 10% ammonia solution and 2.04 ml (0.06 mol) of 5% hydrogen peroxide solution, add them to the round-bottom flask in step (1) in sequence, and mix with salicylaldehyde and disodium hydrogen phosphate;

[0047] (3) Place the round-bottom flask containing the reaction materials and catalyst in step (2) in an ice-water bath of an ultrasonic reactor, wherein the temperature of the ice-water bath is 0-4°C, the ultrasonic frequency is set to 65 kHz, the power is 400 W, and the ultrasonic-assisted reaction is performed for 2 hours; after the reaction is completed, filter the reacted material, and the filter residue obtained is the crude product salicylaldehyde azine;

[0048] (4) The crude salicylaldehyde azine obtained in step (3) is washed with water and filtered 2 to 3 times for purification. The resulting crystals are dried to obtain a finished product of high-purity salicylaldehyde azine, which is weighed to be 22.37 g after drying. The yield is calculated based on salicylaldehyde. The molar yield of the product salicylaldehyde azine is 93.1%.

[0049] Example 3

[0050] (1) Take a round-bottom flask, accurately take 9.96 ml (0.10 mol) of salicylaldehyde and 2.84 g (0.02 mol) of disodium hydrogen phosphate powder into the round-bottom flask and set aside;

[0051] (2) Accurately measure 3.56 ml (0.20 mol) of 10% ammonia solution and 2.04 ml (0.06 mol) of 5% hydrogen peroxide solution, add them to the round-bottom flask in step (1) in sequence, and mix with salicylaldehyde and disodium hydrogen phosphate;

[0052] (3) placing the round-bottom flask containing the reaction materials and the catalyst in step (2) in an ice-water bath of an ultrasonic reactor, wherein the temperature of the ice-water bath is 0-4°C, the ultrasonic frequency is set to 60 kHz, the power is 400 W, and the ultrasonic-assisted reaction is performed for 2 hours; after the reaction is completed, filtering the reacted material and the reacted liquid, and the filter residue obtained is the crude product salicylaldehyde azine;

[0053] (4) The crude salicylaldehyde azine obtained in step (3) is washed with water and filtered 2 to 3 times for purification. The resulting crystals are dried to obtain a finished product of high-purity salicylaldehyde azine, which is weighed to be 22.08 g after drying. The yield is calculated based on salicylaldehyde. The molar yield of the product salicylaldehyde azine is 91.9%.

[0054] The present invention does not limit the container used for the reaction to a round-bottom flask, and other reaction containers can be used, preferably a glass reaction container. The containers used for the reaction and separation in the above embodiments should not be construed as limiting the present invention.

[0055] The invention provides a method for rapid synthesis of salicylaldehyde azine assisted by ultrasound, which realizes rapid and efficient preparation of salicylaldehyde azine by means of ultrasonic wave radiation-assisted reaction, and has the advantages of simple reaction equipment, non-toxic raw materials, high yield, fast speed, easy operation, no other by-products, low cost, easy separation and purification, etc. Compared with traditional synthesis methods, ultrasonic technology has the advantages of simple operation, short reaction time, high efficiency and low energy consumption, etc. The method of the invention is simple and easy to operate, and only requires one step of reaction to generate the target product, and has good industrial application prospects.

[0056] The above is only an embodiment of the present invention, and does not limit the present invention in any form. The present invention can also have other forms of embodiments according to the above structures and functions, which are not listed one by one. Therefore, any simple modification, equivalent change and modification made by any technician familiar with the profession to the above embodiment according to the technical essence of the present invention without departing from the scope of the technical solution of the present invention still falls within the scope of the technical solution of the present invention.

Claims

1. A method for rapid synthesis of salicylaldehyde azine assisted by ultrasound, characterized in that The following steps are involved: (1) Add salicylaldehyde into a round-bottom flask, and add a 10% by mass ammonia solution, a 5% by mass hydrogen peroxide solution and disodium hydrogen phosphate powder into the round-bottom flask; wherein the molar ratio of NH3 in the ammonia solution to salicylaldehyde is (2-3):1, the molar ratio of hydrogen peroxide to salicylaldehyde is (0.5-0.6):1, and the molar ratio of disodium hydrogen phosphate to salicylaldehyde is (0.1-0.2):1; (2) Place the round-bottom flask containing the reaction materials in step (1) in an ice-water bath of an ultrasonic reactor, set the ultrasonic frequency to 60-65 kHz, the power to 400 W, and use ultrasonic-assisted reaction for 2-3 hours; (3) After the reaction is completed, the reacted material is filtered, and the filter residue obtained is the crude product salicylaldehyde azine; (4) Wash and filter the crude salicylaldehyde azine obtained in step (3) 2 to 3 times. The obtained crystals are dried to obtain the finished product salicylaldehyde azine, whose chemical structure is .

2. The method for rapid synthesis of salicylaldehyde azine by ultrasound-assisted method according to claim 1, characterized in that In step (1), when adding the hydrogen peroxide solution, it should be slowly poured into the round-bottom flask along the wall of the container.

3. The method for rapid synthesis of salicylaldehyde azine by ultrasound-assisted method according to claim 1, characterized in that In step (2), the temperature of the ice water bath is 0-4°C.

4. The method for rapid synthesis of salicylaldehyde azine by ultrasound-assisted method according to claim 1, characterized in that In step (4), the crystals are dried in an oven at 37°C under normal pressure.

5. The method for rapid synthesis of salicylaldehyde azine by ultrasound-assisted method according to claim 1, characterized in that The molar yield of the final product salicylaldehyde azine is 88.9-93.1% compared with salicylaldehyde.

Images