A dual temperature limit sensitive reversible color-changing complex and preparation and application thereof

Abstract

The present application belongs to the field of tobacco color development, and particularly relates to a dual-temperature-limit sensitive reversible color-changing compound, which comprises component A and component B in a weight ratio of 1:4-8; the component A comprises a compound of formula 1, and the component B comprises a compound of formula 2; R1 is C1-C4 alkyl; R2 is hydrogen or C1-C6 alkoxy; R3 is C8-C 16 alkyl. The present application also includes preparation and application of the compound. The present application innovatively composites the components, further cooperates the proportion control, unexpectedly realizes synergy based on the interaction of the two, unexpectedly realizes dual-temperature-limit sensitive reversible color-changing, that is, the compound can realize effective color development at a certain temperature, and can realize effective color development at both temperature rise and temperature drop.

Description

Technical Field

[0001] This invention belongs to the tobacco industry, specifically relating to temperature-sensitive tobacco. Background Technology

[0002] Reversible color-changing compounds are a type of color-changing technology that can exhibit different temperatures under varying conditions and can repeatedly develop and decolorize. Conditions that cause the compound to change color typically include temperature, humidity, pressure, light intensity, and pH, and the form of the reversible color-changing compound often varies depending on the conditions. Reversible color-changing compounds are already beginning to be used in tobacco, for example, by impregnating tobacco paper with reversible color-changing compounds before packaging it into cigarettes. During smoking, the temperature varies at different stages of the smoke, resulting in different colors.

[0003] Current reversible color-changing materials typically use bisphenol A (BPA) and bisphenol S (BS) as color-developing agents to cause color changes in the colorant. However, BPA and BS are recognized carcinogenic compounds. Although they offer good color development, their use as color-developing agents is prohibited in tobacco, a food product. Furthermore, most current reversible color-changing compounds are limited to temperature-induced decolorization and low-temperature color development, while temperature changes in tobacco are primarily temperature-increasing. Therefore, there is a need to develop reversible color-changing compounds that can achieve high-temperature color development and low-temperature decolorization. Another point is that all current reversible color-changing compounds develop and decolorize at a single critical temperature; above the critical temperature, one color is observed, and below the critical temperature, another color is observed. This results in overly monotonous color variations.

[0004] Therefore, the use of non-toxic and harmless color developers that can be applied to tobacco is of great significance for reversible color-changing compound formulations for tobacco. Summary of the Invention

[0005] To address the problems existing in the prior art, the primary objective of this invention is to provide a thermosensitive color-changing compound with dual temperature limits, which aims to provide a thermosensitive color-changing compound that can develop color when heated or cooled.

[0006] The second objective of this invention is to provide a method for preparing and applying the aforementioned dual-temperature-limit sensitive reversible color-changing compound.

[0007] A third objective of this invention is to provide an article comprising the aforementioned dual-temperature-limit-sensitive reversible color-changing compound.

[0008] A dual-temperature-limit sensitive reversible color-changing compound comprising component A and component B in a weight ratio of 1:4 to 8; wherein component A comprises a compound of formula 1; and wherein component B comprises a compound of formula 2.

[0009]

[0010] R1 is a C1-C4 alkyl group; R2 is hydrogen or a C1-C6 alkoxy group; R3 is a C8-C6 alkyl group. 16 Alkyl groups.

[0011] This invention innovatively demonstrates that combining Equations 1 and 2, and further coordinating the joint control of their proportions, can unexpectedly achieve synergy based on their interaction, and can unexpectedly achieve dual-temperature-limit sensitive reversible color change. That is, it can achieve effective color development by both heating and cooling at a certain temperature.

[0012] In this invention, R1 in Formula 1 is methyl or ethyl.

[0013] In this invention, R2 in Formula 1 is hydrogen or methoxy; preferably H. Research in this invention shows that by using the preferred compound, combined with other components and parameters, synergy can be further achieved, resulting in superior dual-temperature zone color-changing advantages. For example, similar color-changing effects can be achieved at both low and high temperatures.

[0014] In this invention, in Equation 2, R3 is C 10 ~C 14 Straight-chain alkyl groups.

[0015] In this invention, the weight ratio of component A to component B is 1:4.5 to 5.5; more specifically, 1:5. At the aforementioned ratio, the components can work synergistically to further improve the dual-temperature-zone dual-color-changing effect.

[0016] The dual-temperature-limit sensitive reversible color-changing compound of the present invention further comprises component C, which is a compound with the structure of formula 3.

[0017]

[0018] R4 is a C1 to C4 alkyl group.

[0019] In this invention, the weight ratio of component C to component A is 0.5 to 2:1, and more preferably 1 to 1.5:1.

[0020] The dual-temperature-limit sensitive reversible color-changing compound of the present invention further comprises component D, which is a compound with the structure of formula 4.

[0021] R5-OH Formula 4

[0022] R5 is C8~C 16 Alkyl groups.

[0023] In this invention, in formula 4, R5 is C 10 ~C 14 Straight-chain alkyl groups.

[0024] In this invention, the weight ratio of component D to component A is 10–50:1, and more specifically, 12–15:1. At the aforementioned ratio, the components can work synergistically to improve the dual-temperature-zone dual-color-changing effect.

[0025] The present invention also provides a method for preparing the aforementioned dual-temperature-limit sensitive reversible color-changing compound, wherein the components are mixed to obtain the compound.

[0026] The present invention also includes the application of the aforementioned dual-temperature-limit sensitive reversible color-changing compound, which is used to prepare a material that is white at temperature T and colored both above and below temperature T, wherein the temperature T is 30-40°C.

[0027] The present invention demonstrates that the dual-temperature-limit sensitive reversible color-changing compound, based on the synergistic physicochemical effect between its components, can unexpectedly exhibit effective color development under both heating and cooling conditions.

[0028] The application described in this invention involves adding it as an additive to herbal products to produce tobacco products with reversible color change that is sensitive to dual temperature limits.

[0029] The present invention also provides a product with dual temperature limit sensitive reversible color change, which comprises the dual temperature limit sensitive reversible color change compound described in the present invention, or is prepared from the dual temperature limit sensitive reversible color change compound.

[0030] Beneficial effects

[0031] The color change phenomenon of the dual-temperature-limit sensitive reversible thermochromic compound of the present invention is as follows: it appears dark below 30°C, gradually turns white between 30 and 34°C, remains white between 34 and 40°C, gradually turns dark again between 40 and 46°C, and reappears as dark above 46°C. It has excellent dual-temperature-range color development characteristics.

[0032] The method for preparing the reversible color-changing compound sensitive to dual temperature limits described in this invention is simple, the material is highly safe, the color is bright, the color-changing sensitivity is high, the reversibility is good, and it has good application prospects. Attached Figure Description

[0033] Figure 1 The figure shows the proton NMR spectrum of Equation 1A in CDCl3, with the horizontal axis representing chemical shift and the vertical axis representing intensity.

[0034] Figure 2 The figure shows the carbon NMR spectrum of Equation 1A in CDCl3, with the horizontal axis representing chemical shift and the vertical axis representing intensity.

[0035] Figure 3 The figure shows the 1H NMR spectrum of Equation 1B in CDCl3, with the horizontal axis representing chemical shift and the vertical axis representing intensity.

[0036] Figure 4 The figure shows the carbon NMR spectrum of Equation 1B in CDCl3, with the horizontal axis representing chemical shift and the vertical axis representing intensity.

[0037] Figure 5 The following are color change diagrams of the compound in Example 3 under cooling and heating conditions;

[0038] Figure 6 The following are color change diagrams of the compound in Example 4 during cooling and heating.

[0039] Figure 7 The image shows the color changes of the compound in Example 5 during cooling and heating.

[0040] Figure 8 The image shows the color changes of the compound in Comparative Example 1 during cooling and heating.

[0041] Specific implementation examples

[0042] In this invention, as an optional solution, Equation 1 is typically implemented using Equations 1A and 1B:

[0043]

[0044] As an optional solution, Equation 2 uses Equation 2A as a typical implementation:

[0045]

[0046] As an optional solution, Equation 3 uses Equation 3A as a typical implementation scheme:

[0047]

[0048] As an optional solution, Equation 4 uses Equation 4A as a typical implementation scheme:

[0049]

[0050] Example 1:

[0051] Synthesis of Formula 1A:

[0052]

[0053] (a) 4.1 mmol (0.5 g) of m-methoxyaniline, 1-bromoethane (8.5 mmol), K₂CO₃ (8.0 mmol, 1.0 g), and tetrabutylammonium bromide (1.5 mmol, 0.5 g) were dissolved in 30 mL of a mixed solution of isopropanol / water (v / v, 1:1), and the mixture was heated under reflux for 5 h. After cooling to room temperature, the mixture was extracted three times (30 mL × 3) with CH₂Cl₂. The organic phase was collected and dried over anhydrous Na₂SO₄. The organic solvent was removed under reduced pressure to obtain a crude product, which was purified by column chromatography to give a colorless oily liquid (compound 1) in 50%–65% yield.

[0054] (b) Compound 1 was dissolved in anhydrous dichloromethane and stirred at -78°C for 10 min under Ar protection. 2M BBr3 was added dropwise, and stirring continued for 1 h. The mixture was then transferred to 30°C and reacted for 6 h. After the reaction was complete, the mixture was cooled to room temperature, neutralized with saturated sodium bicarbonate solution, and then extracted three times with dichloromethane. The organic phase was collected, dried over anhydrous sodium sulfate, and the organic solvent was removed by vacuum distillation. The resulting product was purified by column chromatography to obtain compound 2.

[0055] (c) Compound 2 and phthalic anhydride were dissolved in toluene and heated under Ar protection under reflux for 4 h. The reaction solution was cooled to 50–60 °C, and a 35% NaOH solution was added. The reaction was carried out at 90 °C for 6 h. The reaction solution was cooled to room temperature, poured into ice water, and acidified with concentrated hydrochloric acid to pH 3–4. The mixture was stirred at room temperature for 2 h. The reaction was then quenched with saturated brine. The resulting reaction mixture was extracted three times with ethyl acetate. The organic phase was collected and dried over anhydrous Na₂SO₄. The organic solvent was removed under reduced pressure, and the mixture was purified by column chromatography to give a brown solid compound 3.

[0056] (d) Compound 3 (10.0 mmol) and phenol (11.0 mmol) were dissolved in 30 mL of methanesulfonic acid, and the mixture was heated to 95 °C under Ar gas protection for 4–10 h. The reactants were poured into 100 mL of crushed ice, and the pH was adjusted to 9–10 with 30% NaOH aqueous solution. After standing for 30 minutes, the precipitate was collected by filtration and recrystallized from anhydrous ethanol to give a pink solid powder with a yield of 50%.

[0057] The characterization data are as follows: 1HNMR(400MHz, CDCl3)δ7.98(dd,J=31.4,7.5Hz,1H),7.73–7.32(m,3H),7.24–7.09(m,2H),7.02–6.90(m,1H),6.72(ddd,J=7 3.5,37.1,5.2Hz,2H),6.54–6.34(m,1H),6.23(d,J=54.1Hz,1H),3.34(dq,J=20.9,7.1Hz,4H),1.16(dt,J=14.2,7.1Hz,6H). 13 C NMR (100MHz, CDCl3) δ170.0,169.7,156.3,155.7,153.3,152.9,152.4,151.8,149.8,135.0,134.1,131.8,130.4,129.7,129.3,128.9, 128.1,127.8,127.2,126.2,125.1,124.8,124.2,123.3,120.7,119.4,117.1,115.9,115.4,108.5,105.0,97.7,92.3,84.5,44.2,12.6.

[0058] Example 2: Synthesis of Formula 1B:

[0059]

[0060] Compared with Example 1, the only difference is that the phenolic component in step d is changed. The difference in step d is as follows:

[0061] Compound 3 (10.0 mmol) and p-methoxyphenol (11.0 mmol) were dissolved in 30 mL of methanesulfonic acid, and the mixture was heated to 95 °C under Ar gas protection for 4–10 h. The reactants were then poured into 100 mL of crushed ice, and the pH was adjusted to 9–10 with 30% NaOH aqueous solution. After standing for 30 minutes, the precipitate was collected by filtration and recrystallized from anhydrous ethanol to give a pink solid powder with a yield of 67%.

[0062] The characterization data are as follows: 1 H NMR(400MHz, DMSO-d6)δ8.01(d,J=7.5Hz,1H),7.85–7.70(m,2H),7.31(dd,J=14.8,8.3Hz,2H),7.11(dd,J=9.1, 3.0Hz,1H),6.53–6.41(m,3H),6.11(d,J=3.0Hz,1H),3.58(s,3H),3.36(q,J=7.0Hz,4H),1.09(t,J=7.0Hz,6H).13 C NMR (100MHz, CDCl3) δ170.42,155.99,154.07,153.82,150.44,146.93,135.61,130.30,129.61,127.79,12 5.72,124.84,120.66,118.75,118.01,112.25,109.10,105.42,98.37,85.10,56.50,45.29,30.50,13.34.

[0063] Example 3: Preparation Experiment of Red-Colorless-Red Reversible Color-Changing Complex Sensitive to Dual Temperature Limits

[0064] 1.4 g of Formula 4A was placed in a three-necked flask and stirred in a water bath at 65°C. After the temperature reached 65°C, 100.0 mg of Formula 1A and 500.0 mg of Formula 2A were added, and stirring was continued for 1 hour. After cooling, a reversible color-changing compound sensitive to both dark purple and colorless-blue-violet temperature limits was obtained.

[0065] The reversible color-changing compound was heated to a melt, poured into a transparent glass bottle, and cooled to room temperature. Color changes were monitored using a water bath at temperatures ranging from 10 to 50°C, and photographs were taken for record-keeping. Figure 5 As can be seen, it appears red below 30℃, gradually turns white between 30 and 34℃, appears white between 36 and 40℃, gradually turns red between 40 and 46℃, and appears red above 46℃.

[0066] Example 4: Preparation Experiment of Pink-Colorless-Red Reversible Color-Changing Complex Sensitive to Dual Temperature Limits

[0067] 2.8 g of Formula 4A was placed in a three-necked flask and stirred in a 65°C water bath. After the temperature reached 65°C, 200.0 mg of Formula 1B and 1.0 g of Formula 2A were added, and stirring was continued for 1 hour. After cooling, a reversible color-changing compound sensitive to both dark purple and colorless-blue-violet temperature limits was obtained.

[0068] The reversible color-changing compound was heated to a melt, poured into a transparent glass bottle, and cooled to room temperature. Color changes were monitored using a water bath at temperatures ranging from 10 to 50°C, and photographs were taken for record-keeping. Figure 6 As can be seen, it appears pink below 30℃, gradually turns white between 30 and 34℃, appears white between 36 and 40℃, gradually turns red between 40 and 46℃, and appears red above 46℃.

[0069] Example 5: Preparation Experiment of a Reversible Color-Changing Complex Sensitive to Two Temperature Limits: Dark Purple-Colorless-Blue Purple

[0070] 7.0 g of Formula 4A was placed in a three-necked flask and stirred in a 65°C water bath. After the temperature reached 65°C, 500.0 mg of Formula 1A, 500.0 mg of Formula 3A and 2.5 g of Formula 2A were added, and stirring was continued for 1 hour. After cooling, a reversible color-changing compound sensitive to both dark purple and colorless-blue-purple temperature limits was obtained.

[0071] The reversible color-changing compound was heated to a melt, poured into a transparent glass bottle, and cooled to room temperature. Color changes were monitored using a water bath at temperatures ranging from 10 to 50°C, and photographs were taken for record-keeping. Figure 7 As can be seen, it appears dark purple below 30℃, gradually turns white between 30 and 34℃, appears white between 36 and 40℃, gradually turns bluish-purple between 40 and 46℃, and appears bluish-purple above 46℃.

[0072] Comparative Example 1

[0073] 7.0 g of Formula 4A was placed in a three-necked flask and stirred in a 65°C water bath. After the temperature reached 65°C, 500.0 mg of Formula 3A and 2.5 g of Formula 2A were added, and stirring was continued for 1 hour. After cooling, a reversible color-changing compound sensitive to both light blue and colorless-blue temperature limits was obtained.

[0074] The reversible color-changing compound was heated to a melt, poured into a transparent glass bottle, and cooled to room temperature. Color changes were monitored using a water bath at temperatures ranging from 10 to 50°C, and photographs were taken for record-keeping. The results are shown below. Figure 8 It develops color when heated, but the color development is not obvious when cooled.

Claims

1. A dual-temperature-limit sensitive reversible color-changing compound, characterized in that, It comprises component A and component B in a weight ratio of 1:4 to 8; component A comprises a compound of formula 1; and component B comprises a compound of formula 2. R1 is a C1-C4 alkyl group; R2 is hydrogen or a C1-C6 alkoxy group; R3 is a C8-C6 alkyl group. 16 Alkyl groups.

2. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 1, characterized in that, In Formula 1, R1 is methyl or ethyl, and R2 is hydrogen or methoxy.

3. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 1, characterized in that, In Equation 2, R3 is C 10 ~C 14 Straight-chain alkyl groups.

4. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 1, characterized in that, It also contains component C, which is a compound with the structure of formula 3; The R4 is a C1 to C4 alkyl group.

5. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 4, characterized in that, The weight ratio of component C to component A is 0.5 to 2:

1.

6. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 1, characterized in that, It also contains component D, which is a compound with the structure of formula 4; R5-OH Formula 4 R5 is C8~C 16 Alkyl groups.

7. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 6, characterized in that, In Equation 4, R5 is C 10 ~C 14 Straight-chain alkyl groups.

8. The dual-temperature-limit sensitive reversible color-changing compound as described in claim 6 or 7, characterized in that, The weight ratio of component D to component A is 10 to 50:

1.

9. A method for preparing a dual-temperature-limit sensitive reversible color-changing compound according to any one of claims 1 to 8, characterized in that, Mix the ingredients together to obtain the final product.

10. An application of the dual-temperature-limit sensitive reversible color-changing compound according to any one of claims 1 to 8, characterized in that, The material is prepared to be white at temperature T, and to be colored both above and below temperature T, wherein the temperature T is 30-40°C.

11. The application as described in claim 10, characterized in that, It is added as an additive to herbal products to produce tobacco products with reversible color change that is sensitive to dual temperature limits.

12. A product with dual temperature limit sensitive reversible color change, characterized in that, The compound comprising the dual temperature limit sensitive reversible color-changing compound as described in any one of claims 1 to 8, or prepared from the dual temperature limit sensitive reversible color-changing compound.

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