Method for controlling conversion of a reaction using temperature-induced multi-component droplet type transition

Abstract

The application discloses a method for regulating reaction conversion rate by using temperature-induced multi-component droplet type transition. The method dissolves benzaldehyde in n-heptane as a solvent phase 1, dissolves perfluorodecylamine in fluorocarbon oil FC-770 as a solvent phase 2, and dissolves mercaptoacetic acid in an SDS aqueous solution as an aqueous phase. The solvent phase 1, the solvent phase 2 and the aqueous phase are mixed and emulsified to form a temperature-sensitive composite emulsion reactor. The opening and closing of the reaction are controlled by adjusting the temperature in the range of 5-60 DEG C, the spontaneous formation of the emulsion morphology is realized, and the spontaneous control of the conversion rate is realized. The conversion rate can be precisely regulated in the range of 0-100% within 30 hours, and the method has certain application prospects in intelligent control of industrial production.

Description

Technical Field

[0001] This invention belongs to the field of chemical reaction regulation and relates to a method for regulating reaction conversion rate by using temperature-induced changes in the type of multi-component droplets. Background Technology

[0002] Traditional methods often fail to provide convenient and precise control over reaction rates. Slow-moving chemical reactions are typically accelerated by adding catalysts, increasing temperature, or applying external stirring. However, most fast-moving reactions lack a unified, quick, and convenient method for controlling and monitoring their rates.

[0003] Composite emulsions are complex polydisperse systems formed by the mixing of three phases, where reactants can dissolve in different internal phases. This allows reactants to be isolated or contacted under the control of the emulsion morphology. Currently, the irritant-responsive structural changes of emulsions mainly focus on temperature response, carbon dioxide response, pH response, and light response. Liu et al. prepared a carbon dioxide-responsive microemulsion. The introduction of CO2 caused the emulsion to break down, while the introduction of N2 caused it to recover (Liu, Dongfang, Huang, et al. CO2-Responsive Surfactant-Free Microemulsion[J]. Langmuir, 2018, 34, 30, 8910-8916.). Zhang et al. utilized the addition of thermosensitive functional monomers to emulsion systems to achieve thermosensitive responses. The prepared emulsions could form oil-in-water emulsions at low temperatures, and the emulsions would demulsify when the temperature increased. This release method has great potential in the biological field (Zhang Y, Feng Y. Stimuli-responsive microemulsions: State-of-the-art and future prospects-ScienceDirect[J]. Curr Opin Colloid In,49:27-41.2020.). Brown et al. prepared pH-responsive spherical micelles. When the pH value changed, the structure changed from spherical micelles to rod micelles and finally to completely closed vesicles, realizing multi-level structural changes (P. Brown, C. P. Butts, and J. Eastoe, Stimuli-responsive surfactants. Soft Matter 9(8),2365-2374.2013.). Eastoe et al. prepared water-in-oil emulsions using photoresponsive surfactants. When exposed to ultraviolet light, the emulsions gradually demulsified (Eastoe J, Dominguez MS, Cumber H, Wyatt P, Light-sensitive microemulsions. Langmuir. 2004, 20: 1120-1125.).

[0004] However, the methods described above mainly focus on single-sided emulsion systems, where all emulsion droplets are composed of a single substance and are isotropic. Therefore, the responsiveness control of emulsions primarily involves irritant emulsification and demulsification. Whether it's carbon dioxide response, pH response, or light response, applying these methods to actual production inevitably requires more complex working environments or more sophisticated equipment. Summary of the Invention

[0005] The purpose of this invention is to provide a method for regulating reaction conversion rate by utilizing temperature-induced changes in the type of multi-component droplets.

[0006] The technical solution to achieve the purpose of this invention is as follows:

[0007] A method for regulating reaction conversion rate by utilizing temperature-induced droplet type transition in multi-component liquids includes the following steps:

[0008] (1) Benzaldehyde is dissolved in n-heptane as solvent phase 1, perfluorodecylamine is dissolved in fluorocarbon oil FC-770 as solvent phase 2, and mercaptoacetic acid is dissolved in sodium dodecyl sulfate (SDS) aqueous solution as aqueous phase. Solvent phase 1 and solvent phase 2 are first heated and mixed at 50-70°C until the solvent phases disappear into layers as the inner solvent phase. Then the inner solvent phase and the aqueous phase are heated and mixed at 50-70°C to emulsify and form an emulsion.

[0009] (2) If it is necessary to control the reaction conversion rate to 0-14%, the emulsion should be placed at 5-13℃ for static reaction, and the emulsion morphology should be mixed single-sided type.

[0010] If the reaction conversion rate needs to be controlled at 14-55%, the emulsion is placed at 13-30°C for static reaction. The emulsion morphology is a mixture of single-sided and double-sided types, with an intermediate state of Janus type.

[0011] If it is necessary to control the reaction conversion rate to 55-69%, the emulsion should be placed at 30-40°C for static reaction, and the emulsion morphology will be bimorphic.

[0012] If the reaction conversion rate needs to be controlled at 69-100%, the emulsion should be placed at 40-60°C for static reaction, and the emulsion morphology should be uniform and single-sided.

[0013] Furthermore, in step 1, the emulsification method is either vortex oscillation emulsification or shear emulsification.

[0014] Further, in step 1, the concentration of benzaldehyde in solvent phase 1 is 2-200 mmol / L; the concentration of perfluorodecylamine in solvent phase 2 is 2-200 mmol / L; the concentration of thioglycolic acid in the aqueous phase is 2-200 mmol / L; and the concentration of sodium dodecyl sulfate in the aqueous solution is 15-300 mmol / L. In a specific embodiment of the present invention, taking an example where the concentration of benzaldehyde in solvent phase 1 is 20 mmol / L; the concentration of perfluorodecylamine in solvent phase 2 is 20 mmol / L; the concentration of thioglycolic acid in the aqueous phase is 20 mmol / L; and the concentration of sodium dodecyl sulfate in the aqueous solution is 60 mmol / L.

[0015] Further, in step 1, the volume ratio of solvent phase 1 to solvent phase 2 is 3:1 to 1:3; the volume ratio of the internal solvent phase to the aqueous phase is 2:1 to 1:2. In a specific embodiment of the present invention, a volume ratio of solvent phase 1, solvent phase 2, and aqueous phase of 1:1:2 is taken as an example.

[0016] Furthermore, in step 2, the static reaction time is 20-30 h at 5-13℃; 15-20 h at 13-30℃; 10-15 h at 30-40℃; and 8-10 h at 40-60℃.

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

[0018] (1) This invention uses SDS as a surfactant, whose solubility changes with temperature. It has a Krafft point of 8°C, and the solubility of SDS increases rapidly after exceeding the Krafft point. When the external temperature changes, the amphiphilic activity of the SDS amphiphilic molecules also changes. Simultaneously, a temperature-sensitive composite emulsion microreactor is prepared by using fluorocarbon oil and hydrocarbon oil, whose miscibility changes sensitively with temperature, as two solvent phases. The temperature-sensitive composite emulsion microreactor of this invention exhibits a change in structural type with temperature and is highly sensitive to the change. Under the condition of constant composition and ratio, as the ambient temperature increases, the emulsion structure completes a continuous and controllable transformation of four types: mixed single-sided, Janus type, dual type, and homogeneous single-sided. When the temperature decreases, the emulsion structure can undergo a reversible structural transformation from homogeneous single-sided to mixed single-sided. With the help of the reversible transformation of the emulsion structure, the reaction rate can also undergo a reversible transformation.

[0019] (2) This invention discloses for the first time a temperature-sensitive composite emulsion microreactor in which the reaction occurs at the interface of the temperature-sensitive emulsion phase. The temperature-sensitive composite emulsion microreactor can utilize the temperature-sensitive response to regulate the changes in emulsion morphology at multiple levels, thereby regulating the reaction conversion rate. Compared with the traditional stirred reactor, it has lower requirements for reaction equipment, is easier to implement in industrial applications, and is convenient to monitor, providing a foundation for large-scale intelligent control in future production. Attached Figure Description

[0020] Figure 1 This is a schematic diagram illustrating the temperature-induced structural type transformation of multi-component droplets.

[0021] Figure 2 The images show the morphology of FC-770 / n-heptane / SDS emulsions after reaction at different temperatures for 0 h, 15 h, 30 h, and 40 h, where ad: 50 °C, a1-d1: 30 °C.

[0022] Figure 3The images show the morphology of the FC-770 / n-heptane / SDS emulsion after reaction at 10℃ for 0h, 15h, 30h, and 40h, where ad represents the upper layer and a1-d1 represent the lower layer.

[0023] Figure 4 The effect of temperature on the morphology of FC-770 / n-heptane / SDS emulsion is shown, where a: 50℃, b: 30℃, c: 13℃, d: 10℃.

[0024] Figure 5 The reaction kinetics curves (a) of the FC-770 / n-decane / SDS three-phase stirred system and (b) of the FC-770 / n-heptane / SDS emulsion microreactor system at different temperatures are shown.

[0025] Figure 6 The 1H NMR spectrum and physical image of the reaction product 3-(perfluorodecyl)-2-phenylthiazolidin-4-one are shown.

[0026] Figure 7 Kinetic curves of the FC-770 / n-heptane / SDS emulsion microreactor and the FC-770 / n-decane / SDS three-phase stirred system at different temperatures after 30 h of reaction.

[0027] Figure 8 The kinetic curves are for the temperature-controlled reaction of the FC-770 / n-heptane / SDS emulsion microreactor system. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to the embodiments and accompanying drawings.

[0029] Example 1

[0030] The concentrations of the reactants benzaldehyde, perfluorodecylamine, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution as the aqueous phase, with the volume ratio of solvent phase 1:solvent phase 2:water phase controlled at 1:1:2. Solvent phase 1 and solvent phase 2 were then mixed to form the inner solvent phase, and heated together with the outer aqueous phase in water at 50°C until the solvent phases disappeared. The inner solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain the O1 / O2 / W type emulsion microreactor. The prepared O1 / O2 / W type emulsion microreactor was then placed in different temperatures to form different morphologies, thereby controlling the reaction at a specific rate. Figure 1It can be seen that below 13℃, the emulsion morphology is a mixed single-sided type; between 13-30℃, a mixture of single-sided and dual-sided types coexist; between 30-40℃, it completely transforms into a dual-sided type; and above 40℃, it is mainly a homogeneous single-sided type. During the cooling process, a reversible change trend can be observed.

[0031] Example 2

[0032] The concentrations of the reactants benzaldehyde, perfluorodecylamine, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution as the aqueous phase, with the volume ratio of solvent phase 1:solvent phase 2:aqueous phase controlled at 1:1:2. Solvent phase 1 and solvent phase 2 were then mixed to form the inner solvent phase, and heated together with the outer aqueous phase in water at 50°C until the solvent phases disappeared. The inner solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain the O1 / O2 / W type emulsion microreactor. It was then placed in a constant temperature environment of 50°C for static reaction, and samples were taken at 0h, 15h, 30h, and 40h for morphological observation under a microscope. The results are as follows: Figure 2 As shown in figures a to d; the samples were placed in a constant 30°C environment for static reaction, and samples were taken at 0h, 15h, 30h, and 40h for observation of morphological changes under a microscope. The results are as follows. Figure 2 As shown in a1 to d1. Figure 2 It can be seen that under the reaction conditions of 50℃, the emulsion morphology remains uniform and single-sided within 40 hours. Under the reaction conditions of 30℃, the emulsion morphology remains bimodal within 40 hours.

[0033] Example 3

[0034] The concentrations of the reactants benzaldehyde, perfluorodecylamine, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution as the aqueous phase, with the volume ratio of solvent phase 1:solvent phase 2:aqueous phase controlled at 1:1:2. Solvent phase 1 and solvent phase 2 were then mixed to form the inner solvent phase, and heated together with the outer aqueous phase in water at 50°C until the solvent phases disappeared. The inner solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain the O1 / O2 / W type emulsion microreactor. The reactor was then placed in a constant temperature environment of 10°C for static reaction, and samples of the upper layer of solution were taken at 0 h, 15 h, 30 h, and 40 h for microscopic observation of morphological changes. The results are as follows: Figure 3 As shown in figures a to d; samples from the lower layer of the solution were taken at 0h, 15h, 30h, and 40h and observed under a microscope to check the morphological changes. The results are as follows. Figure 3As shown in a1 to d1. Figure 3 It can be seen that under the reaction conditions of 10℃, the morphology of the upper emulsion is an O1 / W type single-sided emulsion within 40h; the morphology of the lower emulsion is an O2 / W type single-sided emulsion within 40h.

[0035] Example 4

[0036] The concentrations of the reactants perfluorodecylamine, benzaldehyde, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution as the aqueous phase, with the volume ratio of solvent phase 1:solvent phase 2:aqueous phase controlled at 1:1:2. Solvent phase 1 and solvent phase 2 were then mixed to form the inner solvent phase, and heated together with the outer aqueous phase in water at 50°C until the solvent phases disappeared. The inner solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain the O1 / O2 / W type emulsion microreactor. The microreactor was placed at 50°C, 30°C, 13°C, and 10°C, and the results are as follows. Figure 4 As shown in a~b in the diagram. From Figure 4 It can be seen that the emulsion has a uniform single-sided morphology at 50℃; a dual morphology at 30℃; a Janus-type morphology briefly appears at 13℃; and a mixed single-sided morphology at 10℃.

[0037] Example 5

[0038] (1) The concentrations of the reactants perfluorodecylamine, benzaldehyde, and mercaptoacetic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-decane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Mercaptoacetic acid was dissolved in water as the aqueous phase, and the volume ratio of solvent phase 1:solvent phase 2:water phase was controlled at 1:1:2. The mixed solution was subjected to three-phase stirring at 5℃, 30℃, and 50℃. During the reaction, acetonitrile was continuously added to break the emulsion and perform reaction kinetic tests. The conversion rate of benzaldehyde was measured as follows: Figure 5 As shown in 'a'.

[0039] (2) The concentrations of the reactants perfluorodecylamine, benzaldehyde, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution as the aqueous phase, and the volume ratio of solvent phase 1:solvent phase 2:water phase was controlled at 1:1:2. The internal solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain the O1 / O2 / W type emulsion microreactor. The emulsion was placed at 5℃, 30℃, and 50℃ for reaction, and acetonitrile was continuously added during the reaction to break the emulsion and conduct reaction kinetic tests. The product conversion rate was measured as follows: Figure 5As shown in b in the figure.

[0040] Depend on Figure 5 As shown in Figure a, the three-phase stirred reaction at 5℃, 30℃, and 50℃ reaches a plateau after 10 hours, with a conversion rate of 60-70% during the plateau period. The final conversion rate within 30 hours is between 70-80%, indicating that temperature has no significant effect on the conversion rate. Figure 5 As shown in b, the emulsion morphology at 10℃ is a mixed single-sided type with a reaction conversion rate of 9%, the emulsion morphology at 30℃ is a dual type with a reaction conversion rate of 59%, and the emulsion morphology at 50℃ is a mixed type with a reaction conversion rate of 98%. Temperature has a controlling effect on the reaction conversion rate.

[0041] Example 6

[0042] 0.1 mmol of SDS was dissolved in 3 ml of water and magnetically stirred until completely dissolved. Then, 1 mmol of perfluorodecylamine, 2 mmol of benzaldehyde, and 3 mmol of mercaptoacetic acid were added sequentially to the flask. The prepared reaction solution was placed at 25 °C and reacted at 800 rpm for 18 h. After the reaction was complete, the product was separated and analyzed by 1H NMR. The 1H NMR spectrum of the product 3-(perfluorodecyl)-2-phenylthiazolidin-4-one was obtained, as shown below. Figure 6 As shown. By Figure 6 As can be seen, the 1H NMR spectrum confirmed that the final reaction product was 3-(perfluorodecyl)-2-phenylthiazolidin-4-one.

[0043] Example 7

[0044] (1) The concentrations of the reactants perfluorodecylamine, benzaldehyde, and mercaptoacetic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-decane and FC-770, respectively, as solvent phase 1 and solvent phase 2. An aqueous solution of mercaptoacetic acid was used as the aqueous phase, and the volume ratio of solvent phase 1:solvent phase 2:aqueous phase was controlled at 1:1:2. The mixed solution was reacted at different temperatures under static conditions. During the reaction, acetonitrile was continuously added to break the emulsion, and reaction kinetics were tested to detect the equilibrium conversion rate. The results are as follows: Figure 7 As shown by the green line in the image.

[0045] (2) The concentrations of the reactants perfluorodecylamine, benzaldehyde, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, respectively, as solvent phase 1 and solvent phase 2. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution as the aqueous phase, and the volume ratio of solvent phase 1:solvent phase 2:water phase was controlled at 1:1:2. The internal solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain the O1 / O2 / W type emulsion microreactor. The emulsion was allowed to react at different temperatures for 30 h, and acetonitrile was continuously added during the reaction to break the emulsion and conduct reaction kinetic tests to detect the equilibrium conversion rate. The results are as follows: Figure 7 The broken line in the figure is shown.

[0046] like Figure 7 As shown by the green line, when the temperature increases from 5℃ to 60℃, the three-phase reaction conversion rate under static reaction conditions is only 3%. Figure 7 As shown by the broken line, when the reaction temperature is controlled below 13℃, the emulsion morphology is a mixed single-sided type with a reaction rate of 11-14%; when the reaction temperature is controlled between 13-30℃, the emulsion morphology is a mixture of single-sided and dual types with a reaction rate of 14-55%; when the reaction temperature is controlled between 30-40℃, the emulsion morphology completely transforms into a dual type with a reaction rate of 55-69%; and when the reaction temperature is controlled above 40℃, the emulsion morphology is mainly mixed type with a reaction rate of 69-97%.

[0047] Example 8

[0048] The concentrations of the reactants perfluorodecylamine, benzaldehyde, and thioglycolic acid were all controlled at 20 mmol / L. Benzaldehyde and perfluorodecylamine were dissolved in n-heptane and FC-770, serving as solvent phase 1 and solvent phase 2, respectively. Thioglycolic acid was dissolved in a 60 mmol / L sodium dodecyl sulfate aqueous solution, serving as the aqueous phase, with a volume ratio of solvent phase 1:solvent phase 2:water phase of 1:1:2. The internal solvent phase was poured into the aqueous phase and vortexed for three minutes to obtain an O1 / O2 / W type emulsion microreactor. The emulsion was allowed to stand at a reaction temperature of 10℃ for 8 hours, then the temperature was increased to 30℃ for 21 hours, and this cycle was repeated three times. During the reaction, acetonitrile was continuously added to break the emulsion for reaction kinetic testing, and the equilibrium conversion rate was measured. Figure 8 As shown.

[0049] from Figure 8 It can be seen that when the reaction temperature is controlled at 30℃, the emulsion morphology is biphasic within 8 hours, the reaction conversion rate gradually increases, the reaction remains on, and the average reaction rate is 2.125% / h. When the reaction temperature is controlled at 10℃, the emulsion morphology is mixed monophasic within 21 hours, the average reaction rate is 0% / h, and the reaction is locked. Repeated temperature control results in a reversible switching of the reaction state.

Claims

1. A method for regulating reaction conversion rate by utilizing temperature-induced droplet type transition in multi-component liquids, characterized in that, Includes the following steps: (1) Benzaldehyde is dissolved in n-heptane as solvent phase 1, perfluorodecylamine is dissolved in fluorocarbon oil FC-770 as solvent phase 2, and mercaptoacetic acid is dissolved in sodium dodecyl sulfate aqueous solution as aqueous phase. Solvent phase 1 and solvent phase 2 are heated and mixed at 50~70℃ until the solvent phases disappear to form an inner solvent phase. Then the inner solvent phase and aqueous phase are heated and mixed at 50~70℃ to emulsify and form an emulsion. (2) If the reaction conversion rate needs to be controlled at 11~14%, the emulsion should be placed at 5~13 ℃ for static reaction, and the emulsion morphology should be mixed single-sided type; If the reaction conversion rate needs to be controlled at 14-55% but not equal to 14%, the emulsion is placed in a static environment at 13-30℃ but not equal to 13℃. The emulsion morphology is a mixture of single-sided and double-sided types, with an intermediate state of Janus type. If it is necessary to control the reaction conversion rate to 55-69% but not equal to 55%, the emulsion should be placed at 30-40℃ but not equal to 30℃ for static reaction, and the emulsion morphology will be bimorphic. If the reaction conversion rate needs to be controlled at 69-100% but not equal to 69%, the emulsion should be placed at 40-60℃ but not equal to 40℃ for static reaction, and the emulsion morphology should be uniform single-sided.

2. The method according to claim 1, characterized in that, In step (1), the emulsification method is either vortex oscillation emulsification or shear emulsification.

3. The method according to claim 1, characterized in that, In step (1), the concentration of benzaldehyde in solvent phase 1 is 2-200 mmol / L; the concentration of perfluorodecylamine in solvent phase 2 is 2-200 mmol / L; the concentration of mercaptoacetic acid in aqueous phase is 2-200 mmol / L; and the concentration of sodium dodecyl sulfate in aqueous solution is 15-300 mmol / L.

4. The method according to claim 1, characterized in that, In step (1), the concentration of benzaldehyde in solvent phase 1 is 20 mmol / L; the concentration of perfluorodecylamine in solvent phase 2 is 20 mmol / L; the concentration of mercaptoacetic acid in aqueous phase is 20 mmol / L; and the concentration of sodium dodecyl sulfate in aqueous solution is 60 mmol / L.

5. The method according to claim 1, characterized in that, In step (1), the volume ratio of solvent phase 1 to solvent phase 2 is 3:1-1:3; the volume ratio of internal solvent phase to water phase is 2:1-1:

2.

6. The method according to claim 1, characterized in that, In step (1), the volume ratio of solvent phase 1, solvent phase 2 and water phase is 1:1:

2.

7. The method according to claim 1, characterized in that, In step (2), the static reaction time is 20-30 h at 5-13 ℃; 15-20 h at 13-30 ℃; 10-15 h at 30-40 ℃; and 8-10 h at 40-60 ℃.

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