Synthesis method of novel green environment-friendly bisoxalate cold light source material

Abstract

The invention relates to the technical field of cold light source material preparation, and particularly discloses a novel green environment-friendly bis-oxalate cold light source material synthesis method which comprises the following steps: S1, dissolving vanillin in dichloromethane (DCM), and stirring until vanillin is completely dissolved; s2, placing the reaction system in an ice-water bath, cooling to 10 DEG C or below, and adding pyridine; s3, uniformly mixing oxalyl chloride and DCM, slowly dropwise adding the mixture into the reaction system in S2 for 20 minutes, and separating out white precipitate in the reaction process; s4, removing the ice bath, and continuously stirring and reacting at room temperature; the vanillin is adopted as the raw material, use of a high-toxicity chlorine-containing precursor is avoided, meanwhile, dangerous chemicals such as concentrated sulfuric acid and chlorine do not need to be introduced in the synthesis process, and therefore the safety risk and environmental pollution in the production process are remarkably reduced, in addition, the reaction is carried out under the mild low-temperature condition, and the production cost is reduced. The energy consumption problem and equipment loss caused by high temperature and high pressure are avoided, so that the whole process is more environment-friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of cold light source material preparation, and particularly relates to a method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material. Background Art

[0002] In the field of cold light source material preparation technology, with the advancement of science and technology and the enhancement of environmental awareness, the demand for high-efficiency and environmentally friendly cold light source materials is growing. Cold light source materials have shown great application potential in many fields such as lighting, display, and indication due to their low energy consumption, long life and environmental protection characteristics. At present, there are many cold light source materials on the market. Among them, cold light source materials based on oxalate compounds have attracted much attention due to their unique luminescent properties. This type of material is usually synthesized through specific chemical reactions and can emit bright and long-lasting light under specific excitation conditions. It is widely used in luminous signs, emergency lighting, decorative lighting and other fields.

[0003] However, the existing synthesis technology of oxalate cold light source materials still has significant shortcomings, especially in terms of environmental protection and safety. Traditional synthesis methods often rely on highly toxic chlorine-containing precursors, such as 2,3,5-trichloro-6-hydroxybenzoic acid amyl ester, etc. These raw materials not only pose a threat to human health, but also produce a large amount of chlorine-containing wastewater and corrosive waste acid during the production process, causing serious pollution to the environment. In addition, these synthesis processes usually need to be carried out under high temperature and high pressure conditions, which not only have high energy consumption, but also have strict requirements on equipment, increasing production costs and safety hazards. More importantly, the oxalate cold light source materials prepared by existing technologies still have room for improvement in luminescence performance, especially in terms of luminescence intensity and durability, which are difficult to meet the needs of high-end application fields, so staff need to improve them. Summary of the Invention

[0004] The object of the present invention is to provide a method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material comprises the following steps:

[0007] S1. Dissolve vanillin in dichloromethane (DCM) and stir until completely dissolved;

[0008] S2. Place the reaction system in an ice-water bath, cool to below 10°C, and add pyridine;

[0009] S3, oxalyl chloride and DCM were mixed evenly, and slowly added dropwise to the reaction system in S2 over a period of 20 minutes. A white precipitate was precipitated during the reaction;

[0010] S4, remove the ice bath and continue stirring the reaction at room temperature;

[0011] S5. Filter the reaction product and vacuum dry it in a warm water bath at 45° C. under a vacuum degree of 0.1 MPa to obtain the target product, bis(4-formyl-2-methoxyphenyl) oxalate.

[0012] Preferably, the feed ratio of vanillin to oxalyl chloride is 3 g of vanillin corresponding to 1 ml of oxalyl chloride.

[0013] Preferably, the solvent for dissolving vanillin in S1 is 40 g DCM.

[0014] Preferably, the amount of pyridine added to S2 is 2 ml.

[0015] Preferably, the mixing ratio of oxalyl chloride and DCM in S3 is 1 ml oxalyl chloride corresponding to 20 ml DCM.

[0016] Preferably, the vacuum drying condition in S5 is a 45° C. warm water bath with a vacuum degree of 0.1 MPa.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) By using vanillin as a raw material, the use of highly toxic chlorine-containing precursors in the existing technology is avoided. At the same time, there is no need to introduce hazardous chemicals such as concentrated sulfuric acid and chlorine during the synthesis process, thereby significantly reducing the safety risks and environmental pollution in the production process. In addition, the reaction is carried out under mild low-temperature conditions, avoiding the energy consumption problems and equipment loss caused by high temperature and high pressure, making the entire process more green and environmentally friendly.

[0019] (2) By optimizing the reaction system, the target product, bis(4-formyl-2-methoxyphenyl) oxalate, has good solubility in low-toxic ethyl acetate, and can achieve efficient luminescence without the addition of plasticizers such as dibutyl phthalate. The methoxy group in the molecular structure forms hydrogen bonds with the solvent, further improving the stability and luminescence durability of the material, thereby achieving better cold light source performance.

[0020] (3) By precisely controlling the reaction conditions and post-processing steps, such as the temperature control of the ice-water bath and the setting of vacuum drying parameters, the high purity and high yield of the product were ensured, making the synthesis method easy to operate and reproducible, providing a reliable technical foundation for subsequent industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a preparation flow chart of the present invention. DETAILED DESCRIPTION

[0022] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0023] Example 1:

[0024] Raw materials and instruments

[0025] Vanillin: 3 g, dichloromethane (DCM): 40 g, pyridine: 2 ml, oxalyl chloride: 1 ml, DCM (for diluting oxalyl chloride): 20 ml;

[0026] Reaction apparatus: 250 ml flask (equipped with a magnetic stirrer), ice-water bath, constant pressure dropping funnel, vacuum drying oven;

[0027] Others: thermometer, Buchner funnel, filter paper, vacuum pump.

[0028] Experimental procedures

[0029] Dissolve vanillin: Add 3 g vanillin and 40 g DCM to a 250 ml flask. Turn on magnetic stirring and stir at room temperature until the vanillin is completely dissolved to form a homogeneous solution.

[0030] Cool down and add pyridine: Place the flask in an ice-water bath and continue stirring until the reaction temperature stabilizes below 10°C. Then, slowly add 2 ml of pyridine to the flask, maintaining a low temperature.

[0031] Prepare oxalyl chloride solution: Mix 1 ml of oxalyl chloride with 20 ml of DCM in a constant pressure dropping funnel and stir evenly to obtain a DCM diluted solution of oxalyl chloride.

[0032] Add oxalyl chloride solution dropwise: While maintaining an ice-water bath, slowly add the oxalyl chloride-DCM mixture dropwise to the flask, controlling the addition rate to complete the addition within 20 minutes. During the addition, a white precipitate will gradually form in the reaction system.

[0033] Reaction at room temperature: After the addition is complete, remove the ice-water bath and allow the reaction system to naturally warm to room temperature (about 25°C). Continue stirring and reacting for 1 hour to ensure complete reaction.

[0034] Filtration and drying: The reaction mixture was filtered through a Buchner funnel to collect the white solid precipitate. The filter cake was transferred to a vacuum drying oven and dried to a constant weight in a 45°C warm water bath at a vacuum of 0.1 MPa to obtain a white powder product.

[0035] Experimental results

[0036] Product: bis(4-formyl-2-methoxyphenyl) oxalate;

[0037] Yield: 3.27 g;

[0038] Yield: 92.63%.

[0039] Product characterization

[0040] Solubility test: The product has good solubility in ethyl acetate. The methoxy group forms intermolecular hydrogen bonds with the solvent, which significantly improves the solubility.

[0041] Luminescence properties: In the low-toxic ethyl acetate system, the product exhibits excellent luminescence intensity and persistence, without the need to add additives such as dibutyl phthalate.

[0042] Example 2:

[0043] Raw materials and instruments

[0044] Vanillin: 6 g, dichloromethane (DCM): 80 g, pyridine: 4 ml, oxalyl chloride: 2 ml, DCM (for diluting oxalyl chloride): 40 ml;

[0045] Reaction apparatus: 500 ml flask (equipped with mechanical stirrer), ice salt bath (for more precise temperature control), constant pressure dropping funnel, vacuum drying oven;

[0046] Others: precision thermometer (±0.1℃), Büchner funnel (sand core, G3), circulating water vacuum pump.

[0047] Experimental procedures

[0048] Dissolve vanillin: Add 6 g of vanillin and 80 g of DCM to a 500 ml flask, stir mechanically at 300 rpm, and dissolve in a 25°C water bath for 30 minutes until completely transparent.

[0049] Deep cooling and pyridine activation: Use an ice-salt bath (CaCl2 / ice = 1:3) and control the system temperature to 5±1°C. Slowly add 4 ml of pyridine dropwise (controlled by a syringe pump, 0.2 ml / min) and maintain stirring at low temperature for 20 minutes.

[0050] Accurate preparation of oxalyl chloride solution: Mix 2 ml of oxalyl chloride with 40 ml of DCM in a constant pressure dropping funnel, purge with nitrogen to prevent moisture absorption, and pre-cool to 5°C for use.

[0051] Gradient dropwise reaction: adopt segmented dropwise addition strategy:

[0052] Stage 1 (0-10 min): add 1 / 3 of the solution dropwise and maintain at 5°C;

[0053] Second stage (10-15min): Heat to 8°C and add the remaining 2 / 3 of the solution dropwise;

[0054] The third stage (15-20min): maintain 8℃ for maturation.

[0055] Post-treatment optimization: Filtration: Wash the precipitate three times with a pre-cooled (5°C) DCM / methanol (9:1) mixture;

[0056] Drying: step-by-step drying (40°C for 1 hour to 45°C for 2 hours to 50°C for 1 hour), vacuum degree 0.08-0.1 MPa dynamically adjusted.

[0057] Experimental results

[0058] Product properties: off-white crystalline powder (particle size distribution D50 = 35 μm);

[0059] Yield: 6.58 g

[0060] Yield: 93.2%

[0061] Purity: HPLC detection ≥99.1% (area normalization method).

[0062] Performance Testing

[0063] Dissolution kinetics: It takes only 8 minutes to reach saturated dissolution (12.5 mg / ml) in ethyl acetate at 25°C;

[0064] Luminous efficiency: relative luminous intensity reaches 118% of CPPO standard (λex=365nm);

[0065] Stability: 40℃ accelerated test for 14 days, luminescence decay <3%.

[0066] Example 3:

[0067] Raw materials and instruments

[0068] Main reaction materials: Vanillin solution: 15g vanillin dissolved in 200g DCM (concentration 7.5% w / w), pyridine solution: 10ml pyridine + 90ml DCM (10% v / v), oxalyl chloride solution: 5ml oxalyl chloride + 95ml DCM (5% v / v);

[0069] Equipment system: microchannel reactor (material: Hastelloy, channel diameter 1mm, volume 50ml), precision metering pump (flow rate control accuracy ±0.1ml / min), online FTIR monitor (resolution 4cm -1 ), low temperature circulation unit (temperature control range -20 ~ 50 ℃), continuous centrifuge (speed 8000rpm).

[0070] Experimental procedures

[0071] Continuous feeding system construction

[0072] The three streams of materials were respectively passed through 0.22μm PTFE filters and then introduced into the microreactor:

[0073] Channel A: vanillin solution (flow rate 8 ml / min);

[0074] Channel B: pyridine solution (flow rate 1.6 ml / min);

[0075] Channel C: oxalyl chloride solution (flow rate 2.4 ml / min).

[0076] Low temperature reaction control

[0077] The reaction zone temperature was set at 5 ± 0.5 °C (ethylene glycol / water coolant circulation);

[0078] The residence time is precisely controlled to 180 seconds (achieved by adjusting the total flow rate to 12 ml / min);

[0079] Online FTIR real-time monitoring 1720cm -1 (C=O) and 1605 cm -1 (Aromatic ring) characteristic peak changes.

[0080] Continuous post-processing

[0081] The reaction solution was directly passed into a quenching tank (containing 200 ml of 10% NaHCO3 solution);

[0082] The organic phase after phase separation was sieved Dynamic dehydration.

[0083] The crystallization stage adopted a gradient cooling program: 25 °C to 10 °C (2 °C / min) to 5 °C (hold for 30 min) to 0 °C (hold for 15 min);

[0084] Continuous centrifugation (8000 rpm, 10 min), mother liquor recycling rate ≥85%.

[0085] Experimental results

[0086] Space-time yield: 2.18 kg / (L·h) (6.5 times higher than that of batch process).

[0087] Product indicators:

[0088] Yield: 95.7±0.3% (n=5);

[0089] Particle size distribution: D90 = 45 μm (laser diffraction method);

[0090] Residual solvent: DCM <50ppm (GC-MS detection).

[0091] Luminous properties:

[0092] Initial brightness: 15800cd / m 2 (Compared to CPPO benchmark value 10000cd / m 2 );

[0093] Half-life: 72 hours (at 25°C).

[0094] Comparative Example:

[0095] Existing technology (compared with CPPO)

[0096] Technical features:

[0097] Raw materials: 2,3,5-trichloro-6-hydroxybenzoic acid amyl ester is used as a precursor, and multiple steps of chlorination and esterification are required for synthesis.

[0098] Synthesis process:

[0099] Use of high-risk chemicals such as chlorine and concentrated sulfuric acid;

[0100] The reaction conditions are harsh (requires high temperature chlorination at 80°C);

[0101] Produces chlorine-containing wastewater (COD>5000mg / L) and corrosive waste acid (pH<1).

[0102] Product performance:

[0103] Dibutyl phthalate (plasticizer) needs to be added to produce light;

[0104] Luminescence half-life: about 40 hours (25°C);

[0105] Toxicity: Metabolite 2,3,5-trichloro-6-hydroxybenzoic acid amyl ester (LC50 = 12 mg / kg, oral administration in rats).

[0106] Comparative analysis with the embodiment:

[0107]

[0108]

[0109] Key performance comparison chart

[0110] Luminous efficiency comparison:

[0111] Material <![CDATA[Initial brightness (cd / m 2 )]]> Half-life (25℃) CPPO 10,000 40 hours Example 1 11,800 60 hours Example 3 15,800 96 hours

[0112] Environmental friendliness comparison:

[0113] index CPPO Example 3 Toxicity of raw materials high Very low Wastewater COD >5000mg / L <100mg / L Solvent recovery rate Non-recyclable 95％

[0114] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material, characterized in that: The following steps are involved: S1. Dissolve vanillin in dichloromethane (DCM) and stir until completely dissolved; S2. Place the reaction system in an ice-water bath, cool to below 10°C, and add pyridine; S3, oxalyl chloride and DCM were mixed evenly, and slowly added dropwise to the reaction system in S2 over a period of 20 minutes. A white precipitate was precipitated during the reaction; S4, remove the ice bath and continue stirring the reaction at room temperature; S5. Filter the reaction product and vacuum dry it in a warm water bath at 45° C. under a vacuum degree of 0.1 MPa to obtain the target product, bis(4-formyl-2-methoxyphenyl) oxalate.

2. The method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material according to claim 1, characterized in that: The feed ratio of vanillin to oxalyl chloride is 3 g of vanillin corresponding to 1 ml of oxalyl chloride.

3. The method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material according to claim 1, characterized in that: The solvent for dissolving vanillin in S1 is 40 g DCM.

4. The method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material according to claim 1, characterized in that: The amount of pyridine added to the S2 is 2 ml.

5. The method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material according to claim 1, characterized in that: The mixing ratio of oxalyl chloride and DCM in S3 is 1 ml oxalyl chloride corresponding to 20 ml DCM.

6. The method for synthesizing a novel green and environmentally friendly bisoxalate cold light source material according to claim 1, characterized in that: The vacuum drying conditions in S5 are a 45° C. warm water bath and a vacuum degree of 0.1 MPa.

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