A tropine-based conjugated enone derivative and its preparation method and application

Abstract

The present invention provides a tropinone-based conjugated enone derivative and its preparation method and application. The structural formula of the tropinone-based conjugated enone derivative is: The preparation method is to mix and react benzaldehyde substituted with a dialkoxy group, tropinone, a solvent and an alkaline solution, and then cool, filter, wash with water and dry to obtain the tropinone-based conjugated enone derivative. The reaction temperature is 20°C to 80°C, and the reaction time is 6h to 12h. The obtained product has strong adhesive properties. Under the irradiation of a light source of 200nm to 700nm, the solid tropinone-based conjugated enone will use the absorbed light energy as heat energy to melt itself into a liquid and lose its adhesive properties, thereby achieving the effect of light-controlled debonding. The light-controlled debonding adhesive of the present invention is easy to synthesize and easy to clean, and can achieve efficient light-controlled debonding.

Description

Technical Field

[0001] The invention relates to the technical field of adhesive materials, and more particularly to a tropine-based conjugated enone derivative and a preparation method and application thereof. Background Art

[0002] Adhesives are substances that connect two materials through interfacial adhesion and cohesive strength. Adhesives are widely used in daily life and industrial manufacturing. In the assembly and disassembly of temporary structures, the debonding, cleaning and bonding of adhesives are equally important.

[0003] Chinese patent CN104812859A discloses a thermally debondable adhesive product, the applicant is 3M Innovation Co., Ltd., but in some cases, local heating is difficult. Light has the advantages of non-contact and time-space controllable. Changing the adhesive properties of the adhesive by illumination to achieve debonding has very important academic value and practical application value. Chinese patent CN108774151A discloses an azobenzene derivative based on photothermal induction to achieve solid-liquid transition, its preparation method and its application as a light switch adhesive. Under green light, the compound can achieve photothermal solid-liquid phase transition to achieve debonding, but the azobenzene derivative photodebonder reported in the patent requires multi-step synthesis, the cost is relatively high, and the melting point of the azobenzene derivative photodebonder is around 44°C, which means that its use environment cannot be higher than 44°C, and its application range is limited.

[0004] Therefore, it is very necessary to develop an optical switch adhesive that is low in cost, can be used in a wide temperature range, and is easy to debond and clean. Summary of the invention

[0005] In order to solve the technical problems existing in the prior art, the present invention provides a tropine-based conjugated enone derivative and a preparation method and application thereof.

[0006] Conjugated enone compounds are a class of small molecule dyes that can be prepared by the Claisen-Schmidt condensation reaction between specific aldehydes and ketones. Their wide range of synthetic raw materials makes their light absorption ability, melting point and crystallization ability highly adjustable. Under light, conjugated enone compounds hardly emit light, and most of the light energy is converted into heat energy. The above properties make conjugated enone compounds have the potential to achieve solid-liquid phase transition through photothermal effect, with the solid state corresponding to the high adhesion state of the adhesive and the liquid state corresponding to the weak adhesion state of the adhesive. However, to date, there is no technical literature report on conjugated enone compounds as photo-controlled debonding adhesives. In view of this, the development of a low-cost, photo-controlled debonding adhesive of conjugated enone derivatives with adjustable melting point and crystallization properties and photothermal phase transition characteristics has a good application prospect in the field of bonding.

[0007] The present invention uses tropinone and benzaldehyde with a dialkoxy chain to obtain a final tropinone-based conjugated enone derivative through a one-step Claisen-Schmidt condensation. The melting point of the prepared conjugated enone can be adjusted to within 100° C. by adjusting the length of the alkyl chain. The obtained tropinone-based conjugated enone is a yellow crystal with strong adhesive properties. Under the irradiation of a light source of 200nm to 700nm, the solid tropinone-based conjugated enone will use the absorbed light energy as heat energy to melt itself into a liquid, thereby losing the adhesive property.

[0008] The light-controlled debonding adhesive of the present invention is easy to synthesize and clean, can realize efficient light-controlled debonding, and is an adhesive that can be debonded on demand and is easy to use.

[0009] One of the objects of the present invention is to provide a tropone-based conjugated enone derivative.

[0010] The structural formula of the tropine-based conjugated enone derivative is:

[0011]

[0012] Wherein n is any integer from 2 to 12; n is preferably 5, 6, 7 or 8;

[0013] When n is 5, 6, 7, or 8, it has an appropriate melting point and crystallization rate, which is beneficial for achieving photothermal phase transition and being used as an adhesive;

[0014] The tropone-based conjugated enone derivative has photothermal solid-liquid phase transition characteristics.

[0015] The second object of the present invention is to provide a method for preparing a tropine-based conjugated enone derivative, comprising:

[0016] The benzaldehyde substituted with a dialkoxy group, tropinone, a solvent and an alkaline solution are mixed for reaction, and then cooled, filtered, washed with water and dried to obtain the tropinone-based conjugated enone derivative;

[0017] The reaction temperature is 20°C to 80°C; preferably 50°C to 70°C;

[0018] The reaction time is 6h to 12h; preferably 8h to 10h;

[0019] The solvent includes solvent A and solvent B;

[0020] The tropinone-based conjugated enone derivative is obtained by a one-step reaction of tropinone and a benzaldehyde substituted with a dialkoxy group. In the reaction, heating conditions are preferably used. The crude product is precipitated after the reaction solution is cooled, which is equivalent to a recrystallization. After the reaction is completed, the solution is cooled to room temperature, and a yellow precipitate is precipitated. The solid product is filtered and rinsed with deionized water to neutrality. After vacuum drying, a tropinone-based conjugated enone derivative with high purity can be obtained.

[0021] In a preferred embodiment of the present invention,

[0022] The dialkoxy-substituted benzaldehyde, solvent A and alkaline solution are uniformly mixed to obtain a mixture, tropinone is dissolved in solvent B to obtain a tropinone solution, the tropinone solution is dropped into the mixture for reaction, and then cooled, filtered, washed with water and dried to obtain the tropinone-based conjugated enone derivative;

[0023] The method of first mixing the dialkoxy-substituted benzaldehyde, the alkaline solution catalyst and the solvent A and then dropping the tropinone solution into the mixture is conducive to the complete reaction of the tropinone.

[0024] In a preferred embodiment of the present invention,

[0025] The structural formula of the dialkoxy-substituted benzaldehyde is:

[0026]

[0027] Wherein n is any integer from 2 to 12; n is preferably 5, 6, 7 or 8;

[0028] The structural formula of the tropinone is:

[0029]

[0030] In a preferred embodiment of the present invention,

[0031] The molar ratio of the dialkoxy-substituted benzaldehyde to tropinone is (2-3):1; and / or,

[0032] The molar ratio of the base to tropinone is (1-5):1; and / or,

[0033] The mass ratio of solvent A to dialkoxy-substituted benzaldehyde is (10-50):1; and / or,

[0034] The mass ratio of solvent B to tropinone is (5-20):1.

[0035] In a preferred embodiment of the present invention,

[0036] The molar ratio of the dialkoxy-substituted benzaldehyde to tropinone is (2-2.2):1; and / or,

[0037] The molar ratio of the base to tropinone is (2-4):1; and / or,

[0038] The mass ratio of solvent A to dialkoxy-substituted benzaldehyde is (30-40):1; and / or,

[0039] The mass ratio of solvent B to tropinone is (10-15):1.

[0040] In a preferred embodiment of the present invention,

[0041] The solvent A and the solvent B are independently selected from one of methanol, ethanol, isopropanol and tert-butanol; and / or,

[0042] The alkaline solution is an organic alkaline solution or an inorganic alkaline solution.

[0043] In a preferred embodiment of the present invention,

[0044] The organic base is at least one of sodium ethoxide, sodium methoxide and potassium tert-butoxide;

[0045] The inorganic base is at least one of sodium hydroxide, potassium carbonate, potassium hydroxide, lithium hydroxide and ammonium hydroxide;

[0046] The solvent in the alkaline solution is water or ethanol;

[0047] The concentration of the alkaline solution is 0.02 g / mL to 0.25 g / mL.

[0048] The third object of the present invention is to provide a tropone-based conjugated enone derivative prepared by the above method.

[0049] A fourth object of the present invention is to provide a use of a tropine-based conjugated enone derivative in a light-controlled debonding adhesive.

[0050] The tropone-based conjugated enone derivative having photothermal solid-liquid phase transition characteristics can be used for adhesives for photo-controlled debonding.

[0051] The solid optical switch adhesive with adhesive properties absorbs light energy and converts it into heat under the irradiation of a 200nm-700nm light source. The temperature rise causes the tropine-based conjugated enone to melt into a liquid state and lose its adhesive properties. A 405nm LED light source is preferred.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) The present invention synthesizes a tropine-based conjugated enone derivative, which is applied to an adhesive for light-controlled debonding and achieves excellent results;

[0054] (2) The tropine-based conjugated enone derivative synthesized in the present invention has strong absorption in the near-ultraviolet and visible light regions, can efficiently convert light energy into heat energy, and has an excellent photothermal effect. Under the irradiation of a light source of 200nm to 700nm, due to the photothermal effect, a solid-liquid phase transition can occur, thereby achieving the effect of light-controlled debonding;

[0055] (3) The tropine-based conjugated ketene light-controlled adhesive with photothermal phase transition properties synthesized by the present invention has strong adhesion in the solid state, and the melting point is between 75°C and 95°C. Compared with the prior art, it can maintain adhesion in a wider temperature range;

[0056] (4) The tropine-based conjugated enone derivative synthesized by the present invention is easily soluble in common organic solvents such as dichloromethane and is easy to clean after debonding;

[0057] (5) The tropine-based conjugated enone derivative synthesized by the present invention has simple synthesis steps, no purification is required, and has good commercial prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] Figure 1 The absorption spectra of the tropone-based conjugated enone prepared in Examples 1 to 4;

[0059] The light absorbing abilities of Examples 1 to 4 are similar, among which the light absorbing ability of Example 3 is slightly higher, and the peak positions of the maximum absorption wavelengths are substantially the same, which is shown in the figure as a high degree of curve overlap;

[0060] Figure 2 The DSC curves of the tropone-based conjugated enones prepared in Examples 1 to 4;

[0061] The numbers marked in the figure are melting points;

[0062] Figure 3 The temperature change curve of the tropine-based conjugated enone powder prepared in Examples 1 to 4 under irradiation with a 405 nm LED light source;

[0063] The blank is a polytetrafluoroethylene plate;

[0064] Examples 1 to 4 have similar light-thermal performance, as shown in the figure by the high degree of curve overlap;

[0065] Figure 4 This is a photograph of the tropine-based conjugated enone powder prepared in Example 2 after being irradiated with a 405 nm LED light source for 1 minute;

[0066] Most of the powder in the picture has turned into liquid;

[0067] Figure 5 This is a photograph of the tropine-based conjugated enone powder prepared in Example 4 after being irradiated with a 405 nm LED light source for 1 minute;

[0068] In the picture, only the surface powder turns into liquid;

[0069] Figure 6 This is a photo of the tropine-based conjugated ketene prepared in Example 1 bonded to glass;

[0070] In the figure, 2 mg of tropine-based conjugated enone prepared in Example 1 is used to horizontally bond two pieces of glass, and the bonding area is 1.6 cm 2 , hang a weight on the unbonded end of one piece of glass, and use a spring balance to measure the unbonded end of the other piece of glass. It is actually measured that a 5kg weight can be lifted. DETAILED DESCRIPTION

[0071] The present invention is described in detail below in conjunction with specific drawings and embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0072] The dialkoxy-substituted benzaldehyde used in the examples was synthesized in the laboratory, and the reference is: FacileBottom-Up Synthesis of Coronene-based 3-Fold Symmetrical and HighlySubstituted Nanographenes from Simple Aromatics. J.Am.Chem.Soc.2014,136,5057-5064.

[0073] Synthesis of Dialkoxy-Substituted Benzaldehydes:

[0074]

[0075] A mixture of 3,4-dihydroxybenzaldehyde (10 mmol), anhydrous potassium carbonate (40 mmol) and n-bromoalkane (22 mmol) was added to 50 mL of N,N-dimethylformamide and reacted at 85°C for 24 hours under magnetic stirring. After the reaction, the reaction solution was poured into 100 mL of deionized water and extracted with dichloromethane (20 mL×3). The dichloromethane phases were combined and washed with saturated sodium chloride aqueous solution for 3 times (20 mL×3), dried over anhydrous sodium sulfate overnight, and concentrated. The crude product was purified by column chromatography, and the eluent was petroleum ether and ethyl acetate (volume ratio of 20:1). The final product was a white solid, which was a bis-alkoxy-substituted benzaldehyde.

[0076] Test method:

[0077] Photothermal heating curve test: 20 mg of the example compound was placed in a metal aluminum plate and irradiated with a 405 nm LED light source (800 mW / cm 2 ), and use the infrared thermal imager FLIR-E6 to monitor the temperature changes during the illumination process.

[0078] Compound melting point test: 2-10 mg of the sample to be tested was placed in a metal aluminum pan, and the position of the melting peak was monitored using a differential scanning calorimeter (Mettler Toledo). The position of the melting peak during the second heating cycle was taken as the melting point.

[0079] Adhesion performance test: Place a certain amount of the sample to be tested on a clean glass sheet, heat it with a hot plate to melt it, take another glass sheet to cover the liquid surface, apply a certain pressure to make the two glass sheets fit tightly, then cool it at room temperature for 30 minutes to make it fully crystallized, and then load a heavy object on the glass sheet for testing;

[0080] Light-controlled debonding experiment: Take 2 mg of the sample to be tested, place it on a clean glass sheet, heat it with a hot plate to melt it, take another glass sheet to cover the liquid surface, apply a certain pressure to make the two glass sheets fit tightly, then cool at room temperature for 30 minutes to make it fully crystallized, load a 1 kg weight on the bonded glass sheet, and use 405 nm LED light (800 mW / cm 2 ) to illuminate the bonding area and record the time required for the two pieces of bonded glass to separate.

[0081] Example 1

[0082]

[0083] 3,4-di(pentyloxy)benzaldehyde (10mmol, 2.78g) was added to a 250mL three-necked flask, and 85g of ethanol was added. The mixture was stirred at 50°C to dissolve the mixture, and an aqueous solution of sodium hydroxide ((20mmol, 0.8g) / 4mL H2O) was slowly added. Tropinone (5mmol, 0.70g) was dissolved in 7g of ethanol, and the tropinone solution was slowly added dropwise to the above benzaldehyde solution at 50°C using a dropping funnel within 1h, and the total reaction time was 8h (including the dropping time). After the reaction was completed, the mixture was cooled to room temperature, and the product was precipitated. The crude product was filtered to obtain the crude product, and the precipitate was washed with deionized water until it was neutral. The target product was obtained after drying without further purification, namely, a tropinone-based conjugated enone derivative, which can be directly used as an adhesive.

[0084] The structural characterization data of tropine-based conjugated enone derivatives were obtained:

[0085] 1H NMR(400MHz, CDCl3)δ7.79(s,2H),7.02–6.86(m,6H),4.48(s,2H),4.04(q,J=6.8Hz,8H),2.63(s,2H),2 .35(s,3H),2.04(d,J=7.1Hz,2H),1.91–1.76(m,8H),1.52–1.34(m,16H),0.94(td,J=7.1,1.0Hz,12H).

[0086] The peaks with chemical shifts at 7.79 to 6.86 ppm are hydrogens on the benzene ring and the trans double bond; the single peak with a chemical shift at 2.35 ppm is the hydrogen on the N-methyl group on the tropinone ring; the single peak with a chemical shift at 4.48 ppm is the hydrogen on the tertiary carbon in the piperidone ring; the hydrogens at chemical shifts at 2.63 ppm and 2.04 ppm are the hydrogens on the two adjacent methylene groups in the piperidone ring; the remaining peaks can be attributed to the hydrogens of the alkoxy chain; the structure of the target product was confirmed to be correct through the integration and peak attribution of the nuclear magnetic hydrogen spectrum.

[0087] Example 2

[0088]

[0089] 3,4-di(hexyloxy)benzaldehyde (11mmol, 3.37g) was added to a 500mL three-necked flask, and 130g of ethanol was added. The mixture was heated and stirred at 60°C to dissolve the mixture, and an aqueous solution of sodium hydroxide ((10mmol, 0.4g) / 16mLH2O) was slowly added. Tropinone (5mmol, 0.70g) was dissolved in 10g of ethanol, and the tropinone solution was slowly added dropwise to the above benzaldehyde solution at 60°C using a dropping funnel within 1h. The total reaction time was 10h (including the dropping time). After the reaction was complete, the mixture was cooled to room temperature, and the product was precipitated. The crude product was filtered to obtain the crude product, and the precipitate was washed with deionized water until it was neutral. The target product was obtained after drying without further purification, namely, a tropinone-based conjugated enone derivative, which can be directly used as an adhesive.

[0090] Get the structural characterization data of the target product:

[0091] 1H NMR (400MHz, CDCl3) δ7.78(s,2H),7.05–6.80(m,6H),4.47(s,2H),4.03(q,J=6.8Hz,8H),2.62(s,2H),2.34(s,3H),2.04(d ,J=7.1Hz,2H),1.90–1.77(m,8H),1.48(dd,J=12.8,6.9Hz,8H),1.35(dd,J=4.7,2.3Hz,16H),0.91(dd,J=7.0,5.8Hz,12H).

[0092] The peaks with chemical shifts at 7.78 to 6.80 ppm are hydrogens on the benzene ring and the trans double bond; the singlet with chemical shift at 2.34 ppm is hydrogen on the N-methyl group on the tropinone ring; the singlet with chemical shift at 4.47 ppm is hydrogen on the tertiary carbon in the piperidone ring; the hydrogens at chemical shifts at 2.62 ppm and 2.04 ppm are hydrogens on two adjacent methylene groups in the piperidone ring; the remaining peaks can be attributed to hydrogens on the alkoxy chain; the structure of the target product was confirmed to be correct through integration and peak attribution of the nuclear magnetic hydrogen spectrum.

[0093] Example 3

[0094]

[0095] 3,4-di(octyloxy)benzaldehyde (10mmol, 3.62g) was added to a 500mL three-necked flask, and 125g of isopropanol was added. The mixture was heated and stirred at 65°C to dissolve the mixture, and an aqueous solution of sodium hydroxide ((15mmol, 0.6g) / 6mLH2O) was slowly added. Tropinone (5mmol, 0.70g) was dissolved in 7g of ethanol, and the tropinone solution was slowly added dropwise to the above benzaldehyde solution at 65°C using a dropping funnel within 1h. The total reaction time was 9h (including the dropping time). After the reaction was completed, the mixture was cooled to room temperature, and the product was precipitated. The crude product was filtered to obtain the crude product, and the precipitate was washed with deionized water until it was neutral. The target product was obtained after drying without further purification, namely a tropinone-based conjugated enone derivative, which can be directly used as an adhesive.

[0096] Get the structural characterization data of the target product:

[0097] 1H NMR (400MHz, CDCl3) δ7.79 (s, 2H), 7.02–6.88 (m, 6H), 4.48 (s, 2H), 4.03 (q, J = 6.8Hz, 8H), 2.63 (s, 2H), 2.35 (s, 3H), 2.04(d,J=7.0Hz,2H),1.88–1.79(m,8H),1.47(dd,J=13.6,6.8Hz,8H),1.41–1.26(m,32H),0.89(t,J=6.6Hz,12H).

[0098] The peaks with chemical shifts at 7.79 to 6.88 ppm are hydrogens on the benzene ring and the trans double bond; the single peak with a chemical shift at 2.35 ppm is the hydrogen on the N-methyl group on the tropinone ring; the single peak with a chemical shift at 4.48 ppm is the hydrogen on the tertiary carbon in the piperidone ring; the hydrogens at chemical shifts at 2.63 ppm and 2.04 ppm are the hydrogens on the two adjacent methylene groups in the piperidone ring; the remaining peaks can be attributed to the hydrogens of the alkoxy chain; the structure of the target product was confirmed to be correct through the integration and peak attribution of the nuclear magnetic hydrogen spectrum.

[0099] Example 4

[0100]

[0101] 3,4-di(dodecyloxy)benzaldehyde (10mmol, 4.75g) was added to a 500mL three-necked flask, and 140g of methanol was added. The mixture was heated and stirred at 70°C to dissolve the mixture, and an ethanol solution of potassium tert-butoxide ((15mmol, 1.68g) / 10mL of ethanol) was slowly added. Tropinone (5mmol, 0.70g) was dissolved in 10g of ethanol, and the tropinone solution was slowly added dropwise to the alkaline solution of benzaldehyde using a dropping funnel at 70°C within 1h, and the total reaction time was 9h (including the dropping time). After the reaction was completed, the mixture was cooled to room temperature, and the product was precipitated. The crude product was filtered to obtain the crude product, and the precipitate was washed with deionized water until it was neutral. The target product was obtained after drying without further purification, which was a tropinone-based conjugated enone derivative, which could be directly used as an adhesive.

[0102] Get the structural characterization data of the target product:

[0103] 1H NMR(400MHz, CDCl3)δ7.78(s,2H),7.01–6.87(m,6H),4.47(s,2H),4.03(q,J=6.7Hz,8H),2.62(s,2H),2.34(s,3H), 2.03(d,J=7.1Hz,2H),1.89–1.78(m,8H),1.47(dd,J=13.2,6.8Hz,8H),1.38–1.24(m,64H),0.88(t,J=6.8Hz,12H).

[0104] The peaks with chemical shifts at 7.78 to 6.87 ppm are hydrogens on the benzene ring and the trans double bond; the single peak with a chemical shift at 2.34 ppm is the hydrogen on the N-methyl group on the tropinone ring; the single peak with a chemical shift at 4.47 ppm is the hydrogen on the tertiary carbon in the piperidone ring; the hydrogens at chemical shifts at 2.62 ppm and 2.03 ppm are the hydrogens on the two adjacent methylene groups in the piperidone ring; the remaining peaks can be attributed to the hydrogens of the alkoxy chain; the structure of the target product was confirmed to be correct through the integration and peak assignment of the nuclear magnetic hydrogen spectrum.

[0105] The photothermal heating curve test, compound melting point test, bonding performance test and photo-controlled debonding experiment were respectively carried out on Examples 1 to 4.

[0106] Figure 1 The absorption spectra of the tropine-based conjugated enone prepared in Examples 1 to 4 are as follows: Figure 1 As shown, Examples 1 to 4 have strong absorption at 250 nm to 700 nm.

[0107] Figure 3 The temperature change curve of the tropine-based conjugated ketene powder prepared in Examples 1 to 4 under irradiation with a 405 nm LED light source is shown in FIG. Figure 3 As shown, under the irradiation of 405 nm LED light source, the powders of Examples 1 to 4 can be heated to about 110° C. after 5 minutes.

[0108] from Figure 1 and Figure 3 It can be seen that the change of the alkyl chain has little effect on the light absorption ability and photothermal conversion ability of the tropine-based conjugated enone;

[0109] Figure 2 The DSC curves of the tropine-based conjugated enones prepared in Examples 1 to 4 are as follows: Figure 2As shown, the melting points of Examples 1 to 4 are 83.2°C, 74.9°C, 82.6°C, and 94.7°C, respectively; indicating that the change in the length of the alkyl chain significantly affects the melting point of the compound, and the realization of the photothermal solid-liquid transition requires that the heat energy generated by the compound after absorbing light is sufficient to heat it to above the melting point, so the melting point affects the debonding efficiency of the compound. For example, in Example 2, debonding only requires 1 minute and 30 seconds of light exposure, while Example 4 requires 8 minutes and 30 seconds of light exposure under the same conditions.

[0110] Figure 4 , Figure 5 The photographs of the tropone-based conjugated ketene powders prepared in Example 2 and Example 4 after being irradiated with a 405nm LED light source for 1 minute show that most of the powder in Example 2 becomes liquid, while only the surface powder in Example 4 becomes liquid. This is because the melting point of Example 4 is higher, so 1 minute of light irradiation is not enough to melt it completely.

[0111] Figure 6 This is a photo of the tropine-based conjugated ketene prepared in Example 1 bonded to glass. Figure 6 As shown, when 2 mg of Example 1 is used as an adhesive, a weight of 5 kg can be lifted; when Examples 2 to 4 are tested, a weight of 5 kg can also be lifted;

[0112] In the light-controlled debonding experiment, when 2 mg of the products obtained in Examples 1 to 4 were bonded to a glass sheet loaded with a 1 kg weight, the bonding area was illuminated by a 405 nm LED light source. After 3 minutes, 1 minute 30 seconds, 3 minutes 10 seconds, and 8 minutes 30 seconds, respectively, the samples between the two pieces of glass in Examples 1 to 4 became liquid and the weight fell off. In contrast, the samples in Examples 1 to 4 that were not illuminated could load a 1 kg weight for 24 hours without debonding.

[0113] In Examples 1 to 4, at 20°C, 30°C, 40°C, 50°C, 60°C, and 70°C, 2 mg of Example 1 as an adhesive can load a 1 kg weight for 24 hours without debonding, indicating that the adhesive provided by the present invention can be used in a wide temperature range. Example 4 can load a 1 kg weight for 24 hours at 80°C without debonding because the melting point of Example 4 is 94.7°C, so it still maintains a solid strong bonding state at 80°C.

[0114] The adhesive provided by the present invention can be easily cleaned by immersing the debonded glass sheets of Examples 1 to 4 in dichloromethane.

[0115] In general, the tropine-based conjugated enone compounds prepared by the present invention have good adhesion to glass, and 2 mg of the sample can load a weight of 5 kg when used as an adhesive. In terms of light-controlled debonding efficiency, when n=5, 6, 7 or 8, the melting point is low, which is conducive to achieving rapid light-controlled debonding; when n is less than 5 or n is greater than 8, the melting point of the compound is high, and the efficiency of light-controlled debonding will be reduced.

Claims

1. A tropine-based conjugated enone derivative, characterized in that: The structural formula of the tropine-based conjugated enone derivative is: Wherein n is any integer between 2 and 12.

2. The tropine-based conjugated enone derivative according to claim 1, characterized in that: n is 5, 6, 7 or 8.

3. A method for preparing a tropinone-based conjugated enone derivative as claimed in claim 1 or 2, characterized in that The method comprises: The dialkoxy-substituted benzaldehyde, solvent A and alkaline solution are uniformly mixed to obtain a mixture, tropinone is dissolved in solvent B to obtain a tropinone solution, the tropinone solution is dropped into the mixture for reaction, and then cooled, filtered, washed with water and dried to obtain the tropinone-based conjugated enone derivative; The reaction temperature is 20℃~80℃; The reaction time is 6h~12h; The solvent A and the solvent B are independently selected from one of methanol, ethanol, isopropanol and tert-butanol.

4. The method for preparing a tropone-based conjugated enone derivative according to claim 3, characterized in that: The reaction temperature is 50°C~70°C; The reaction time is 8h~10h.

5. The method for preparing a tropone-based conjugated enone derivative according to claim 3 or 4, characterized in that: The structural formula of the dialkoxy-substituted benzaldehyde is: Wherein n is any integer between 2 and 12.

6. The method for preparing a tropone-based conjugated enone derivative according to claim 5, characterized in that: n is 5, 6, 7 or 8.

7. The method for preparing a tropone-based conjugated enone derivative according to claim 3 or 4, characterized in that: The molar ratio of the dialkoxy-substituted benzaldehyde to tropinone is (2-3):1; and / or, The molar ratio of the base to tropinone is (1-5):1; and / or, The mass ratio of solvent A to dialkoxy-substituted benzaldehyde is (10-50):1; and / or, The mass ratio of solvent B to tropinone is (5~20):

1.

8. The method for preparing a tropone-based conjugated enone derivative according to claim 7, characterized in that: The molar ratio of the dialkoxy-substituted benzaldehyde to tropinone is (2-2.2):1; and / or, The molar ratio of the base to tropinone is (2-4):1; and / or, The mass ratio of solvent A to dialkoxy-substituted benzaldehyde is (30-40):1; and / or, The mass ratio of solvent B to tropinone is (10~15):

1.

9. The method for preparing a tropone-based conjugated enone derivative according to claim 3 or 4, characterized in that: The alkaline solution is an organic alkaline solution or an inorganic alkaline solution.

10. The method for preparing a tropone-based conjugated enone derivative according to claim 9, characterized in that: The organic base is at least one of sodium ethoxide, sodium methoxide and potassium tert-butoxide; The inorganic base is at least one of sodium hydroxide, potassium carbonate, potassium hydroxide, lithium hydroxide and ammonium hydroxide; The solvent in the alkaline solution is water or ethanol; The concentration of the alkaline solution is 0.02 g / mL to 0.25 g / mL.

11. Use of the tropinone-based conjugated enone derivative according to claim 1 or 2 or the tropinone-based conjugated enone derivative prepared by the method according to any one of claims 3 to 10 in an adhesive for light-controlled debonding.

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