A kind of synthetic method of L-phenylalanine
L-phenylalanine is synthesized from carbon dioxide and nitrophenylethane through photoelectrochemical reaction, which solves the problems of high energy consumption and environmental pollution caused by dependence on petroleum in existing technologies and realizes clean and efficient L-phenylalanine production.
Patent Information
- Application Number
- CN202411057540.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-02
- Publication Date
- 2025-09-05
- Estimated Expiration
- 2044-08-02
AI Technical Summary
Existing L-phenylalanine synthesis methods rely on petroleum-derived raw materials, resulting in long reaction times, high energy consumption, serious environmental pollution, and low synthesis efficiency, making it difficult to achieve economically sustainable production.
L-phenylalanine is synthesized at room temperature and pressure through photoelectrochemical reaction using carbon dioxide and nitrophenylethane as raw materials. A silicon-based cathode photoelectrode covered with a co-catalyst is used, driven by light or electricity, to achieve carbon-nitrogen coupling to synthesize L-phenylalanine.
It reduces energy consumption, reduces pollutant emissions, improves synthesis rate and Faradaic efficiency, achieves clean and efficient L-phenylalanine production, produces high-value chemicals as by-products, and simplifies the process flow.
Smart Images
Figure CN118979262B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of amino acid synthesis, and in particular to a method for synthesizing L-phenylalanine. Background Art
[0002] Amino acids are essential compounds widely used in the food and pharmaceutical industries, with an annual global demand exceeding 5.0×10 5 Tons. Among various amino acid products, L-phenylalanine plays a vital role in the production of pharmaceuticals, medicines, and pharmaceuticals, and is commonly used as a dietary supplement and artificial sweetener. Aspartame, a dipeptide compound composed of L-phenylalanine and L-aspartic acid, is a high-intensity, low-calorie sweetener favored in diet drinks and foods, and market demand for its raw material, L-phenylalanine, is rapidly growing.
[0003] Currently, L-phenylalanine can be produced via chemical synthesis, enzymatic methods, and microbial fermentation. However, all of these methods rely heavily on petroleum-derived raw materials. This reliance results in prolonged reaction times, high energy consumption, extensive use of compressors, and the generation of significant amounts of inorganic waste, raising concerns about sustainability and environmental impact. The complexity of the purification process, coupled with the low efficiency of L-phenylalanine formation due to the similar polarity of the carboxyl substrate and the amino acid product, increases production costs. While microbial fermentation can utilize alternative carbon and nitrogen sources for large-scale L-phenylalanine production, offering advantages such as inexpensive and readily available raw materials, minimal environmental pollution, and high product purity, it has become the primary method for industrial L-phenylalanine production. However, the L-phenylalanine product exerts strong feedback inhibition or repression on the activity or expression of key enzymes in its anabolic pathway, limiting its excessive accumulation. Therefore, there is an urgent need to design efficient and economically viable green L-phenylalanine synthesis strategies, particularly new pathways that utilize clean energy-driven, renewable precursors. Summary of the Invention
[0004] The present invention aims to provide a method for synthesizing L-phenylalanine. The method provided by the present invention uses carbon dioxide and nitrophenylethane as raw materials and is driven by green and clean energy light or photoelectricity to prepare L-phenylalanine. During the reaction, pollutant emissions are low, and the rate and Faradaic efficiency of synthesizing L-phenylalanine are high.
[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:
[0006] The present invention provides a method for synthesizing L-phenylalanine, comprising the following steps:
[0007] The carbon dioxide is introduced into an electrolyte containing nitrophenylethane to undergo a photoelectrochemical reaction to produce L-phenylalanine.
[0008] The cathode photoelectrode used in the photoelectrochemical reaction is prepared from a promoter or a silicon substrate covered with a promoter and titanium oxide.
[0009] Preferably, the flow rate of the carbon dioxide is 10 to 50 mL / min.
[0010] Preferably, the concentration of nitrophenylethane in the electrolyte containing nitrophenylethane is 5mM to 1000mM.
[0011] Preferably, the electrolyte in the electrolyte containing nitrophenylethane is at least one of phosphate buffer, potassium bicarbonate solution, potassium carbonate solution, sodium bicarbonate solution, potassium carbonate solution, hydrochloric acid solution, sulfuric acid solution, sodium hydroxide, and potassium hydroxide.
[0012] Preferably, the co-catalyst is at least one of transition metal oxide particles and monoatomically dispersed transition metals.
[0013] Preferably, the transition metal is at least one of Fe, Co, Ni, Cu, Zn, Mn, and Ti.
[0014] Preferably, the loading amount of the co-catalyst on the cathode photoelectrode is 25 to 100 μg / cm 2 .
[0015] Preferably, the photoelectrochemical reaction is carried out at room temperature and pressure; the time of the photoelectrochemical reaction is 0.5 to 100 hours.
[0016] Preferably, the light intensity of the light source used for the photoelectrochemical reaction is 45 to 550 mW / cm 2 ; The wavelength of the light source is 350~1200nm.
[0017] Preferably, the applied voltage of the photoelectrochemical reaction is -1.8 to 0V.
[0018] The present invention provides a method for synthesizing L-phenylalanine, which uses carbon dioxide (excessive atmospheric pollutant gas) and nitrophenylethane (common organic pollutant) as carbon source and nitrogen source respectively, and uses electricity or photoelectricity as driving force. Under mild conditions of normal temperature and pressure, the synthesis of L-phenylalanine is achieved through a one-step carbon-nitrogen coupling, which reduces the energy barrier for synthesizing L-phenylalanine, thereby reducing energy consumption. At the same time, the by-products ammonia and urea are both high-value chemical products. The method provided by the present invention realizes the direct conversion of pollutants into chemicals, greatly improves the recycling rate of carbon dioxide and nitrophenylethane, and reduces pollution to the atmosphere and the environment. In addition, the light source used in the present invention can be sunlight, which is cleaner and more environmentally friendly, and converts renewable energy into easily storable, high-energy-density L-phenylalanine. Compared with conventional amino acid synthesis requiring the participation of enzymes and microorganisms, the method provided by the present invention has low cost, simple reaction, green and pollution-free, simplified process, and is more efficient, flexible and sustainable. The results of the embodiment show that, using the method provided by the present invention, Example 1 is a high current (100mA / cm 2 ), the synthesis rate of L-phenylalanine can reach 37.51 mg·h -1 cm -2 , the Faradaic efficiency is 18.28%. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 The SEM images of the surface and cross section of the cathode photoelectrode prepared in Example 1 of the present invention are shown, wherein: Figure 1 (a) is the surface of the cathode photoelectrode, Figure 1 (b) is the cross section of the cathode photoelectrode;
[0020] Figure 2 This is a graph showing the change in current density over time during the synthesis of L-phenylalanine in Example 1 of the present invention;
[0021] Figure 3 This is an LSV (Linear Sweep Voltammetry) graph during the synthesis of L-phenylalanine in Example 1 of the present invention, wherein: Figure 3 (a) is the LSV comparison diagram of photocurrent and dark current, Figure 3 (b) is the LSV curve obtained by the change of current density with time under the chopping condition test;
[0022] Figure 4 This is the H-NMR spectrum of the L-phenylalanine product synthesized in Example 1 of the present invention;
[0023] Figure 5 Statistical graphs of L-phenylalanine yield and Faradaic efficiency at different potentials during the synthesis of L-phenylalanine in Example 1 of the present invention;
[0024] Figure 6This is a graph showing the change in current density over time during the synthesis of L-phenylalanine in Example 2 of the present invention;
[0025] Figure 7 Statistical graphs of L-phenylalanine yield and Faradaic efficiency at different potentials during the synthesis of L-phenylalanine in Example 2 of the present invention;
[0026] Figure 8 Statistical graph of L-phenylalanine yield and Faradaic efficiency at different potentials during the synthesis of L-phenylalanine in Example 3 of the present invention. DETAILED DESCRIPTION
[0027] The present invention provides a method for synthesizing L-phenylalanine, comprising the following steps:
[0028] The carbon dioxide is introduced into an electrolyte containing nitrophenylethane to undergo a photoelectrochemical reaction to produce L-phenylalanine.
[0029] The cathode photoelectrode used in the photoelectrochemical reaction is prepared from a promoter or a silicon substrate covered with a promoter and titanium oxide.
[0030] In the present invention, unless otherwise specified, the raw materials used are conventional commercial products in the field.
[0031] In the present invention, the flow rate of the carbon dioxide is preferably 10 to 50 mL / min, more preferably 20 to 40 mL / min, and even more preferably 30 mL / min. The present invention controls the flow rate of the carbon dioxide within the above range to adjust the solubility of the carbon dioxide gas in the electrolyte, thereby achieving the effect of promoting the production of L-phenylalanine through the equilibrium reaction.
[0032] In the present invention, the concentration of nitrophenylethane in the electrolyte containing nitrophenylethane is preferably 5 mM to 1000 mM, more preferably 6 to 800 mM, and even more preferably 10 mM. The present invention controls the concentration of nitrophenylethane within the above range to achieve control of the concentration of reactants around the electrode sheet, thereby achieving the effect of promoting the production of L-phenylalanine through the equilibrium reaction.
[0033] In the present invention, the electrolyte in the electrolyte containing nitrophenylethane is at least one of a phosphate buffer, a potassium bicarbonate solution, a potassium carbonate solution, a sodium bicarbonate solution, a potassium carbonate solution, a hydrochloric acid solution, a sulfuric acid solution, sodium hydroxide, and potassium hydroxide, and is more preferably a phosphate buffer. In the present invention, the pH value of the phosphate buffer is preferably 5.5.
[0034] In the present invention, the co-catalyst is preferably at least one of transition metal oxide particles and monoatomically dispersed transition metals; the transition metal is at least one of Fe, Co, Ni, Cu, Zn, Mn, and Ti, more preferably at least one of Cu and Ti.
[0035] In the present invention, the method for preparing the cathode photoelectrode preferably comprises the following steps:
[0036] (1) subjecting a p-type Si substrate to metal catalytic chemical etching to obtain a pretreated substrate having a porous structure with an average pore diameter of 20 nm to 50 nm and an average pore depth of 50 nm to 200 nm;
[0037] Depositing n-type Si on the surface of the pretreated substrate to obtain an n+p type porous Si substrate;
[0038] (2) forming an amorphous light-transmitting TiO2 semiconductor thin film with a thickness of 6 to 10 nm on the surface of the n+p type porous Si substrate obtained in step (1) by magnetron sputtering as an electron transport layer;
[0039] The magnetron sputtering parameters are as follows: the target material is Ti; the sputtering gas is a mixture of Ar and O2, the total pressure of the sputtering gas is 3.0 Pa, and the O2 partial pressure is 50%; the distance between the target and the substrate is 10 cm; the deposition time is 80 min; the RF power applied to the target is 150 W; and the chamber temperature at the end of the deposition is 40°C.
[0040] (3) mixing the co-catalyst, isopropyl alcohol and Nafion (perfluorosulfonic acid polymer, 5 wt%), and dispersing the mixture by ultrasonication to obtain a slurry containing a transition metal oxide co-doped carbon composite material;
[0041] The slurry containing the transition metal oxide co-doped carbon composite material is evenly drop-coated on the surface of the TiO2 semiconductor film obtained in step (2), and after natural drying, a catalytic layer is formed to obtain a cathode photoelectrode.
[0042] Compared with traditional coated electrodes, the present invention directly constructs the active material, i.e., the co-catalyst, on a two-dimensional or three-dimensional conductive substrate, i.e., a silicon substrate covered with titanium oxide, to form a nanostructured integrated electrode with a binder-free design, which can promote a significant increase in energy density and power density, thereby improving the speed and efficiency of synthesizing L-phenylalanine.
[0043] In the present invention, the loading amount of the co-catalyst on the cathode photoelectrode is preferably 25 to 100 μg / cm 2 , more preferably 30 to 80 μg / cm 2The present invention controls the loading amount of the co-catalyst on the cathode photoelectrode within the above range to achieve full and complete exposure of the active sites, which helps to improve the catalytic activity.
[0044] In the present invention, the photoelectrochemical reaction is preferably carried out at room temperature and pressure; the time of the photoelectrochemical reaction is preferably 0.5 to 100 hours, more preferably 1 to 20 hours.
[0045] In the present invention, the light intensity of the light source used for the photoelectrochemical reaction is preferably 45 to 550 mW / cm 2 The wavelength of the light source is preferably 350 to 1200 nm. The present invention controls the light intensity and wavelength of the light source within the above range to achieve optimized L-phenylalanine synthesis performance by controlling the light source and wavelength.
[0046] In the present invention, the applied voltage of the photoelectrochemical reaction is preferably -1.8 to 0V.
[0047] In the present invention, the reaction system of the photoelectrochemical reaction preferably includes: using Ag / AgCl as a reference electrode, using platinum carbon as a counter electrode and placing it in the counter electrode compartment, using the cathode photoelectrode as a working electrode and placing it in the working electrode compartment, and the working electrode compartment and the counter electrode compartment are separated by a nafion membrane; adding an electrolyte containing nitrophenylethane to the working electrode compartment and the counter electrode compartment, respectively, and continuously introducing carbon dioxide, turning on the power, and using a light source to irradiate the working electrode, driving the carbon dioxide and the nitrophenylethane in the electrolyte to undergo a photoelectrocatalytic coupling reaction, and preparing L-phenylalanine on the surface of the working electrode.
[0048] The synthesis method of L-phenylalanine provided by the invention has simple operation, mild reaction conditions and is suitable for large-scale production.
[0049] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. 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.
[0050] Example 1
[0051] A method for synthesizing L-phenylalanine comprises the following steps:
[0052] Carbon dioxide was introduced into the electrolyte containing nitrophenylethane at a flow rate of 30 mL / min, and a photoelectrochemical reaction was carried out at room temperature and pressure for 1 hour to produce L-phenylalanine.
[0053] The concentration of nitrophenylethane in the electrolyte containing nitrophenylethane is 10 mM; the electrolyte in the electrolyte containing nitrophenylethane is a phosphate buffer solution with a pH value of 5.5;
[0054] The cathode photoelectrode used in the photoelectrochemical reaction is prepared from a silicon substrate covered with a co-catalyst and titanium oxide, and the co-catalyst loading on the cathode photoelectrode is 50ug / cm 2 , the co-catalyst consists of CuO powder and TiO2 powder in a mass ratio of 1:1;
[0055] The preparation method of the cathode photoelectrode comprises the following steps:
[0056] (1) subjecting a p-type Si substrate to metal catalytic chemical etching to obtain a pretreated substrate having a porous structure with an average pore diameter of 5 to 7 nm and an average pore depth of 200 nm;
[0057] Depositing n-type Si on the surface of the pretreated substrate to obtain an n+p type porous Si substrate;
[0058] (2) forming an amorphous light-transmitting TiO2 semiconductor thin film with a thickness of 5 to 10 nm on the surface of the n+p type porous Si substrate obtained in step (1) by magnetron sputtering as an electron transport layer;
[0059] The parameters of the magnetron sputtering are as follows: the target material is Ti; the sputtering gas is a mixed gas of Ar and O2, the total pressure of the sputtering gas is 3.0 Pa, and the O2 partial pressure is 50%; the distance between the target material and the substrate is 10 cm; the deposition time is 80 min; the RF power applied to the target material is 150 W; and the chamber temperature at the end of deposition is 40°C.
[0060] (3) 2 mg of co-catalyst powder, 960 μL of isopropanol, and 40 μL of Nafion (perfluorosulfonic acid polymer, 5 wt%) were mixed and ultrasonically dispersed for 20 min to obtain a slurry containing a transition metal oxide co-doped carbon composite material;
[0061] The slurry containing the transition metal oxide co-doped carbon composite material is evenly drop-coated on the surface of the TiO2 semiconductor film obtained in step (2), and after natural drying, a catalytic layer is formed to obtain a cathode photoelectrode, which is recorded as CuO / TiO2 / Si photoelectrode;
[0062] The reaction system of the photoelectrochemical reaction includes: using Ag / AgCl as a reference electrode, using platinum carbon as a counter electrode and placing it in the counter electrode compartment, using the cathode photoelectrode as a working electrode and placing it in the working electrode compartment, and separating the working electrode compartment and the counter electrode compartment by a nafion membrane; adding 15mL of an electrolyte containing nitrophenylethane to the working electrode compartment and the counter electrode compartment respectively, and continuously introducing carbon dioxide, turning on the power, applying a voltage of -0.4V, and using a light intensity of 100mW / cm 2 , a light source with a wavelength of 460 nm illuminates the working electrode, driving carbon dioxide to undergo a photoelectrocatalytic coupling reaction with nitrophenylethane in the electrolyte, thereby preparing L-phenylalanine on the surface of the working electrode.
[0063] The surface and cross section of the cathode photoelectrode prepared in Example 1 were characterized using a field emission scanning electron microscope, and the SEM images of the surface and cross section of the cathode photoelectrode prepared in Example 1 were obtained. Figure 1 As shown, Figure 1 (a) is the surface of the cathode photoelectrode, Figure 1 (b) is the cross section of the cathode photoelectrode, Figure 1 It was observed that the cathode photoelectrode prepared in Example 1 consisted of a CuO / TiO2 nanoparticle layer, a TiO2 layer and a Si substrate.
[0064] The electrochemical it (current-time) detection was performed using an Autolab electrochemical workstation to obtain a curve of current density versus time during the synthesis of L-phenylalanine in Example 1. Figure 2 As shown by Figure 2 It can be seen that the photoelectrically driven amino acid synthesis process in Example 1 has good stability.
[0065] The electrochemical detection was performed using an Autolab electrochemical workstation to obtain the LSV (linear sweep voltammetry) curve of the process of synthesizing L-phenylalanine in Example 1. Figure 3 As shown, Figure 3 (a) is the LSV comparison diagram of photocurrent and dark current, Figure 3 (b) is the LSV curve obtained by the change of current density with potential under chopping conditions. Figure 3 It can be seen that the CuO / TiO2 / Si photoelectrode prepared in Example 1 has a good response under light conditions.
[0066] The nuclear magnetic resonance hydrogen spectrum of the L-phenylalanine product synthesized in Example 1 was obtained by nuclear magnetic resonance hydrogen spectrometer. Figure 4 As shown by Figure 4It can be seen that during the photoelectrochemical reaction in Example 1, the CuO / TiO2 / Si photoelectrode catalyzed the reaction of carbon dioxide and nitrophenylethane to produce L-phenylalanine.
[0067] The ninhydrin color reaction was used to detect the L-phenylalanine yield and Faraday efficiency statistics at different potentials during the synthesis of L-phenylalanine in Example 1. Figure 5 As shown, the column is the L-phenylalanine yield, the broken line is the Faraday efficiency, Figure 5 It can be seen that in Example 1, carbon dioxide and nitrophenylethane were used for reductive coupling to form L-phenylalanine, and the yield of L-phenylalanine could reach 37.8 mg·h -1 cm -2 , the Faradaic efficiency can reach 21.2%, with high amino acid yield and Faradaic efficiency.
[0068] Example 2
[0069] L-phenylalanine was synthesized in the same manner as in Example 1, except that TiO2 powder alone was used as a co-catalyst to prepare a TiO2 / Si photoelectrode as a cathode photoelectrode.
[0070] The electrochemical it (current-time) was performed using an Autolab electrochemical workstation to detect the current density change over time during the synthesis of L-phenylalanine in Example 2. Figure 6 As shown by Figure 6 It can be seen that the process of using the TiO2 / Si photoelectrode in Example 2 to promote the reductive coupling of CO2 and nitrophenylethane to form L-phenylalanine has good stability.
[0071] The ninhydrin color reaction was used to detect the L-phenylalanine yield and Faraday efficiency statistics at different potentials during the synthesis of L-phenylalanine in Example 2. Figure 7 As shown, the column is the L-phenylalanine yield, the broken line is the Faraday efficiency, Figure 7 It can be seen that in Example 2, the cocatalyst TiO2 was used to catalyze the reduction coupling of carbon dioxide and nitrophenylethane to form L-phenylalanine, and the L-phenylalanine yield could reach 13.81 mg·h -1 cm -2 , the Faradaic efficiency can reach 6.70%, with high amino acid yield and Faradaic efficiency.
[0072] Example 3
[0073] L-phenylalanine was synthesized in the same manner as in Example 1, except that CuO powder alone was used as a co-catalyst to prepare a CuO / Si photoelectrode as a cathode photoelectrode.
[0074] The statistical graph of the L-phenylalanine yield and Faraday efficiency at different potentials during the synthesis of L-phenylalanine in Example 3 was obtained by ninhydrin color reaction detection. Figure 8 As shown, the column is the L-phenylalanine yield, the broken line is the Faraday efficiency, Figure 8 It can be seen that in Example 3, the cocatalyst CuO was used to catalyze the reductive coupling of carbon dioxide and nitrophenylethane to form L-phenylalanine, and the L-phenylalanine yield was 22.06 mg·h -1 cm -2 , the Faradaic efficiency can reach 11.15%, with high amino acid yield and Faradaic efficiency.
[0075] In summary, using the method provided by the present invention, the cathode photoelectrodes prepared in Examples 1 to 3 have good response under light conditions, and the process of promoting the reductive coupling of CO2 and nitrophenylethane to form L-phenylalanine has good stability. The L-phenylalanine yield can reach 21.2%, and the Faradaic efficiency can reach 37.51 mg·h -1 cm -2 , with high amino acid production and Faradaic efficiency.
[0076] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A method for synthesizing L-phenylalanine, characterized in that: The following steps are involved: The carbon dioxide is introduced into an electrolyte containing nitrophenylethane to undergo a photoelectrochemical reaction to produce L-phenylalanine. The cathode photoelectrode used in the photoelectrochemical reaction is prepared from a promoter or a silicon substrate covered with a promoter and titanium oxide; The co-catalyst is at least one of transition metal oxide particles and monoatomically dispersed transition metals; The light intensity of the light source used in the photoelectrochemical reaction is 45-550 mW / cm 2 ; The wavelength of the light source is 350~1200nm; The applied voltage of the photoelectrochemical reaction is -1.8~0V.
2. The synthesis method according to claim 1, wherein The flow rate of the carbon dioxide is 10-50 mL / min.
3. The synthesis method according to claim 1, wherein The concentration of nitrophenylethane in the electrolyte containing nitrophenylethane is 5mM~1000mM.
4. The synthesis method according to claim 1 or 3, characterized in that The electrolyte in the electrolyte containing nitrophenylethane is at least one of phosphate buffer, potassium bicarbonate solution, potassium carbonate solution, sodium bicarbonate solution, potassium carbonate solution, hydrochloric acid solution, sulfuric acid solution, sodium hydroxide, and potassium hydroxide.
5. The synthesis method according to claim 1, characterized in that The transition metal is at least one of Fe, Co, Ni, Cu, Zn, Mn, and Ti.
6. The synthesis method according to claim 1, characterized in that The loading amount of the co-catalyst on the cathode photoelectrode is 25-100 ug / cm 2 .
7. The synthesis method according to claim 1, characterized in that The photoelectrochemical reaction is carried out at room temperature and pressure; the time of the photoelectrochemical reaction is 0.5 to 100 hours.