Description:FIELD OF THE INVENTION
The present disclosure relates to the field of electrolysis. More particularly, it relates to a process for co-producing fine chemicals and hydrogen through lignin electrolysis.
BACKGROUND OF THE INVENTION
The background information herein below relates to the present disclosure but is not necessarily prior art.
Fossil fuels are a principal source of basic chemical substituents and hydrogen fuel but are also a primary cause of environmental dis-balance. The electrochemical exploitation of lignin biomass provides an environmentally friendly and highly efficient platform for producing hydrogen and fine aromatic chemicals and simultaneously reduces the dependence on fossil fuel resources. Lignin is a complex biopolymer comprising aromatic sub-units linked to various carbon-carbon and carbon-oxygen bonds. Splitting these bonds is essential to convert lignin into small molecular aromatic compounds without breaking the aromatic ring structure. The alkyl-benzene and phenolic compounds are high-value-added fine aromatic compounds that can be recovered from the lignin upon selective cleavage of bonds, especially carbon-carbon linkage.
Liu et al. reported the electrooxidation of bamboo lignin by Pb/PbO2 anode and Cu cathode in an alkaline solution, resulting in vanillin, syringaldehyde, and p-coumaric acid as the products. In the investigation of Pardini and coworkers, aromatic aldehyde and carboxylic acid compounds were found on electrocatalytic oxidation of a lignin ß-O-4 dimeric model compound using Ni electrode at elevated temperature. Cai et al. obtained vanillin, trans-ferulic acid, syringaldehyde, 3-hydroxy-4-methoxyphenyl-ethanone, 4-methoxy-3-methyl-phenol and acetosyringone upon electro redox depolymerization of corn stover lignin, implementing Pb/PbO2 anode and Cu/Ni-Mo-Co cathode in alkaline solution. Steifel et al. employed an electrochemical reactor for lignin depolymerization consisting of an anion exchange membrane (AEM) to evaluate lignin conversion into monomeric products using a nickel-based catalyst. Caravaca et al. demonstrated a continuous flow AEM reactor, where lignin electrolysis was performed at 0 to 1.1 V, lower than the required thermodynamic potential of water electrolysis (> 1.5 V) using commercial Pt-Ru on carbon cloth.
The current processes for lignin electrolysis are limited to batch systems, and production of the recovery of the fine chemicals from the mixture of multiple aromatic chemicals after electrooxidation from the anolyte remains a technological bottleneck. Further improvement in the process and optimization of reaction conditions can result in a high yield of by-products parallel with hydrogen generation. Therefore, improving biomass utilization technologies is of utmost importance, combining efficient hydrogen production and selectivity of desired chemical compounds. Conversely, electrolytic water electrolysis powered by renewable electricity sources is a green way to harvest hydrogen. Still, it is an energetic uphill process that requires significant energy to produce hydrogen at the cathode (~ 50 kWh/kg H2). Mainly because of the slow reaction kinetics of oxygen evolution reaction (OER) at the anode, which requires a large overpotential (> 1.5 V vs. RHE to achieve 10 mA/cm2). Electrolysis of lignin at the anode not only oxidatively decomposes to yield electrons and protons, overcoming the thermodynamic limitation by lowering the potential (< 1 V RHE) needed for electrolytic hydrogen production at the cathode but also simultaneously generates value-added aromatic compounds. During electrolysis, a substantial number of methoxy groups on lignin can be easily hydrolyzed to make oxygenated species such as light alcohols (e.g., methanol). These light oxygenated species readily decompose by electrocatalytic process, given the relatively facile kinetics for hydrogen generation at the cathode replacing conventional water electrolysis, involving oxygen evolution at the anode. Therefore, lignin is a potentially promising source of electron and proton for harvesting hydrogen at the cathode and efficiently generates fine aromatic chemicals.
However, a conventional electrocatalytic process for lignin oxidation has encountered several problems like high consumption of strong base, high temperature and pressure, expensive catalysts, and long run for biomass conversion, which are not attractive from an economic point of view.
Therefore, there is felt a need for a process for co-producing fine chemicals and hydrogen through lignin electrolysis, which mitigates the drawbacks mentioned herein above or at least provides a useful alternative.
OBJECT OF THE INVENTION
Some of the objects of the present disclosure, which at least one embodiment herein satisfies, are as follows:
It is an object of the present disclosure to ameliorate one or more problems of the prior art or to at least provide a useful alternative.
An object of the present disclosure is to provide a process for co-producing fine chemicals and hydrogen through lignin electrolysis.
Another object of the present disclosure is to provide a scalable process that yields fine aromatic chemicals and hydrogen from lignin electrolysis.
Yet another object of the present disclosure is to provide an economically viable process that yields fine aromatic chemicals and hydrogen from lignin electrolysis.
Other objects and advantages of the present disclosure will be more apparent from the following description, which is not intended to limit the scope of the present disclosure.
SUMMARY OF THE INVENTION
The present invention solves the problem of lignin waste disposal and the economical production of clean hydrogen. Large amounts of lignin waste can be treated and converted into useful products owing to the continuous flow operation of the lignin electrolysis process. The value-added fine chemicals are produced by the electrooxidation of lignin which results in the utilization of the waste leading to precious compound generation. Clean hydrogen obtained from the lignin electrolysis can be utilized as fuel for electrical vehicles operated on fuel cells.
In an aspect, the present disclosure relates to a process for co-producing fine chemicals and hydrogen, wherein the process comprising electrochemical oxidation of lignin at an anolyte in a reactor under a constant applied potential to obtain fine chemicals, and the fine chemicals are separated by selectively allowing to pass the fine chemicals through a semi permeable separator to the catholyte in the reactor to obtain the fine chemicals and hydrogen.
In another aspect, the present disclosure relates to a reactor for co-producing fine chemicals and hydrogen, by electrochemical oxidation of lignin as described above.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
The reactor of the present disclosure will now be described with the help of the accompanying drawings, in which:
Figure 1 illustrates a schematic representation of the experimental and reactor setup.
Figure 2a illustrates electrochemical characterizations to evaluate the reactor's performance wherein Linear Sweep Voltammetry (LSV) is measured at room temperature. In Figure 2a, graph A denotes the onset potential for lignin electrolysis whereas graph B denotes the onset potential for water electrolysis.
Figure 2b illustrates electrochemical characterizations to evaluate the reactor's performance wherein LSV is measured at an elevated temperature. In Figure 2b, the graph A denotes the current attained by lignin electrolysis whereas graph B denotes the current attained by water electrolysis.
Figure 2c illustrates electrochemical characterizations (LSV) comparing the performance of a 3D printed device with the commercially available hardware, wherein graph A denotes the current attained by the 3D printed device for lignin electrolysis whereas graph B denotes the current attained by the commercially available hardware for lignin electrolysis.
Figure 3a illustrates electrochemical characterizations to evaluate the reactor's performance wherein Potentiostatic electrochemical impedance spectroscopy (PEIS) is measured at room temperature. In Figure 3a, graph A denotes the charge transfer resistance for the lignin electrolysis whereas graph B denotes the charge transfer resistance for the water electrolysis.
Figure 3b illustrates electrochemical characterizations to evaluate the reactor's performance wherein PEIS is measured at an elevated temperature. In Figure 3b, graph A denotes the current for lignin electrolysis whereas graph B denotes the current for water electrolysis.
Figure 3c illustrates electrochemical characterizations (PEIS) comparing the performance of a 3D printed device with the commercially available hardware, wherein graph A denotes ohmic and the charge transfer resistance for the lignin electrolysis in 3D printed device whereas graph B denotes ohmic and the charge transfer resistance for the lignin electrolysis in the commercially available hardware.
LIST OF REFERENCE NUMERALS USED IN DETAILED DESCRIPTION AND DRAWING

1 Separator
2 Cathode
3 Anode
4 Catholyte channels
5 Anolyte channels
6 Catholyte and hydrogen outlet
7 Anolyte inlet
8 Anolyte and oxygen outlet

DETAILED DESCRIPTION OF THE INVENTION
Embodiments are provided so as to thoroughly and fully convey the scope of the present disclosure to the person skilled in the art. Numerous details are set forth, relating to specific components, and methods, to provide a complete understanding of embodiments of the present disclosure. It will be apparent to the person skilled in the art that the details provided in the embodiments should not be construed to limit the scope of the present disclosure. In some embodiments, well-known processes, well-known apparatus structures, and well-known techniques are not described in detail.
The terminology used, in the present disclosure, is only for the purpose of explaining a particular embodiment and such terminology shall not be considered to limit the scope of the present disclosure. As used in the present disclosure, the forms "a” "an" and "the" may be intended to include the plural forms as well, unless the context clearly suggests otherwise. The terms "comprises" "comprising" “including” and “having” are open-ended transitional phrases and therefore specify the presence of stated features, integers, steps, operations, elements, modules, units and/or components, but do not forbid the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The particular order of steps disclosed in the method and process of the present disclosure is not to be construed as necessarily requiring their performance as described or illustrated. It is also to be understood that additional or alternative steps may be employed.
The terms first, second, third, etc., should not be construed to limit the scope of the present disclosure as the aforementioned terms may be only used to distinguish one element, component, region, layer or section from another component, region, layer or section. Terms such as first, second, third etc., when used herein do not imply a specific sequence or order unless clearly suggested by the present disclosure.
In an aspect, the present disclosure relates to a process for co-producing fine chemicals and hydrogen.
The process comprises the following steps:
Step a. electrochemical oxidation of lignin at an anolyte in a reactor under a constant applied potential to obtain fine chemicals.
In an embodiment, the reactor comprises a separator (1), cathode (2), anode (3), catholyte channels (4), anolyte channels (5), catholyte and hydrogen outlet (6), anolyte inlet (7), and anolyte and oxygen outlet (8).
The separator (1) is a proton or anion exchange semi-permeable separator. The anode and the cathode are separated by the separator (1).
The separator prevents the mixing of anolyte and catholyte, wherein the anolyte comprises lignin and/or water, and wherein said catholyte is an alkaline solution with 1 to 10 molarity.
In an embodiment, the anolyte comprising lignin in an alkaline solution with 10 to 50 wt% is inserted into said reactor through an anolyte inlet (7). The concentration of lignin is in the range of 10 to 50 g/L in 1 M KOH or 0.5 M H2SO4, which is circulated through anolyte channels. The electrochemical oxidation is conducted under an applied voltage in the range of 1.2 to 2.5 V.
In a preferred embodiment, the electrochemical oxidation is conducted under an applied voltage is 1.8 V.
In an embodiment, the lignin is acid-hydrolyzed i.e., pre-treated.
In an embodiment, the lignin anolyte can be a mixture of glucose, xylose-mannose-galactose, and arabinose, partially transferred through semi permeable separator based on diffusivity and flow rate of anolyte.
The electrochemical oxidation of lignin is a continuous flow process, and the reaction time to reach the equilibrium is in the range of 20 hours to 40 hours for a reaction volume in the range of 400 mL to 3000 mL.
In a preferred embodiment, the volume of the electrochemical oxidation of lignin is 3000 mL.
The flow of the lignin anolyte solution is in the range of 50 to 150 mL/min, which is controlled with a peristaltic pump at room temperature.
The cathode (2), and the anode (3) are made of non-precious metals selected from iron, cobalt, nickel, copper, and stainless steel. The electrochemical oxidation of lignin occurs at the anode, and the cathode is partitioned by permeable ion conductive separators.
Step b. The fine chemicals are separated by selectively allowing to pass the fine chemicals through a semi-permeable separator to the catholyte in the reactor to obtain the fine chemicals and hydrogen.
The separator allows for the transport of water through, called drag water, aiding in the completion of the reaction at the cathode.
The vanillic acid, syringic acid, 3,5-dimethoxy-4-hydroxyacetophenone, 2-hydroxy-4-methoxyacetophenone, 4-ethylcathecol, and 2,6-dimethoxyphenol are obtained in anolyte, and wherein vanillin acetate and sinapic acid are obtained in catholyte.
Sinapic acid and the vanillin acetate are obtained in the catholyte drag water which is separated through the semi-permeable separator. The fine chemicals can be further separated by employing downstream processing.
The hydrogen is produced at the cathode (2). The co-production of hydrogen and fine chemicals reduces the cost of green hydrogen.
The process as claimed in claim 1, wherein said process of electrochemical oxidation of lignin is a continuous flow process.
In another aspect, the present disclosure relates to a reactor for co-producing fine chemicals and hydrogen, by electrochemical oxidation of lignin as disclosed above. The reactor comprises separator (1), cathode (2), anode (3), catholyte channels (4), anolyte channels (5), catholyte and hydrogen outlet (6), anolyte inlet (7), and anolyte and oxygen outlet (8).
In an embodiment, the separator (1) is a proton or anion exchange semi-permeable separator.
In an embodiment, the cathode (2), and the anode (3) are made of non-precious metals selected from iron, cobalt, nickel, copper, and stainless steel.
In an embodiment, the anode and the cathode are separated by the separator (1) and prevents the mixing of the anolyte and the catholyte.
In an embodiment, the separator selectively separates the fine chemicals to obtain vanillic acid, syringic acid, 3,5-dimethoxy-4-hydroxyacetophenone, 2-hydroxy-4-methoxyacetophenone, 4-ethylcathecol, and 2,6-dimethoxyphenol in anolyte, and wherein vanillin acetate and sinapic acid are obtained in catholyte.
The schematic of the experimental setup is depicted in Figure 1. The electrochemical flow reactor comprises an anode (3) and cathode (2) over the anolyte channels (5) and the catholyte channels (4), respectively. The anode and the cathode are separated by a separator (1). The separator is selectively permeable and prevents mixing of the anolyte and the catholyte. The anolyte comprising either lignin and/or water is introduced into the reactor through the anolyte inlet (7) and removed through the anolyte and oxygen outlet (8). Under an applied voltage, lignin and/or water electrolysis occurs, leading to hydrogen generation in the cathode and oxygen at the anode. The separator allows for the transport of water through, called drag water, aiding in the completion of the reaction at the cathode. In the case of lignin electrolysis, fine chemical products are formed owing to the electrooxidation of lignin obtained in the anolyte and the drag water obtained in the catholyte.
The foregoing description of the embodiments has been provided for purposes of illustration and not intended to limit the scope of the present disclosure. Individual components of a particular embodiment are generally not limited to that particular embodiment, but, are interchangeable. Such variations are not to be regarded as a departure from the present disclosure, and all such modifications are considered to be within the scope of the present disclosure.
The present disclosure is further described in light of the following experiments which are set forth for illustration purpose only and not to be construed for limiting the scope of the disclosure. The following experiments can be scaled up to industrial/commercial scale and the results obtained can be extrapolated to industrial scale.
EXPERIMENTAL DETAILS
Experiment 1:
The process started by assembling a reactor with a semi-permeable separator sandwiched between the anode and cathode, with a working area of 5 cm2. The anode and cathode were surrounded by a layer of gasket sealing the electrolyte flow. The concentration of lignin was between 10 g/L in 1 M KOH, which was circulated through anolyte channels, while H2 gas and precious fine chemicals in the liquid phase were obtained from catholyte channels under an applied voltage of 1.8 V. The electrolytic process was designed in a reactor having a closed-loop cell system, where an anolyte containing the lignin was sealed in a reservoir and recirculated. The volume of the solution in each reservoir varied from 400 to 3000 mL and was as an anolyte using a peristaltic pump (Cole Parmer Masterflex). The flow of electrolyte solutions was 100 mL/min, controlled with a peristaltic pump at room temperature. A Biologic SP150 potentiostat/galvanostat was used to evaluate the electrochemical performance of the reactor. After that, the linear sweep voltammetry (LSV) was measured in the voltage range of 0 to 2.5 V, and the current was recorded. Potentiostatic electrochemical impedance spectroscopy (PEIS) was performed in the frequency range of 100 kHz to 10 mHz at 1.8 V with an amplitude of 10 mV. The impedance spectroscopy is performed to evaluate ohmic and charge transfer resistance. Electrolysis of biomass was conducted via chronoamperometry (CA) at a constant voltage of 1.8 V for 40 hours, and the corresponding behavior was recorded in terms of time versus current. The electrochemical characterizations (LSV, PEIS, and CA) were performed to determine the performance of the lignin electrolysis using the 3D printed reactor and compared it with conventional water electrolysis. After the electrolysis of lignin, the anolyte and catholyte drag water were collected and subsequently analyzed by liquid chromatography–mass spectroscopy (LC-MS) to determine the products of lignin oxidation in the liquid sample. The performance of the lignin electrolysis was evaluated at room temperature and an elevated temperature. Moreover, the performance of the in-house 3D printed electrochemical reactor was compared with that of the commercially available reactor.
Results:
Electrochemical characterizations were performed to evaluate the reactor's performance and compared the lignin electrolysis with water electrolysis. The experiments were performed at room temperature and an elevated temperature of 70ºC.
For the 3D printed device, the LSV (Figure 2a) at room temperature reveals that the onset potential for lignin electrolysis is lower than that of the water electrolysis. Moreover, the 300 mA is current attained at 1.8 V for the lignin electrolysis, which is more than that of water electrolysis (78 mA at 1.8 V). Moreover, the PEIS (Figure 3a) shows that at room temperature, through the ohmic resistance for both lignin electrolysis and water electrolysis is the same, the charge transfer resistance for the lignin electrolysis (0.70 ?) is less as compared to that of the water electrolysis (1.05 ?).
The elevated temperature drastically increases the performance of the 3D printed reactor (Figure 2b to 2c, and Figure 3b to 3c). At 70ºC and 1.8 V, the current attained by lignin electrolysis is 597 mA, 4.78 times more than that of water electrolysis (125 mA) at the same temperature. Moreover, with an increase in temperature from room temperature to 70ºC, the current for lignin electrolysis increases by 1.99 times. The current increase is due to the faster kinetics at the elevated temperature, which results in higher hydrogen production rates. At 2V, the current attained by the 3D printed reactor is 1358 mA for lignin electrolysis, and that by water electrolysis is 456 mA. The PEIS (Figure 3b) results align well with the LSV curves for the elevated temperature. The ohmic and the charge transfer resistance for the lignin electrolysis is 0.23 and 0.45 ?, respectively, and that for the water electrolysis is 0.4 and 0.88 ?, respectively. The design of the 3D printed reactor, porous electrodes, and the rational choice of the semipermeable separator contribute towards the higher current and lower resistances attained for lignin electrolysis compared to the water electrolysis over the complete voltage range.
The lignin electrolysis in the 3D printed reactor was compared to commercially available hardware (Figure 2c and Figure 3c). The current attained by the 3D printed reactor (1358 mA) for lignin electrolysis at 2 V is 1.22 times more than that in the commercial hardware (1110 mA). The PEIS (Figure 3c) results follow a similar trend. The ohmic and the charge transfer resistance for the 3D printed reactor is 0.23 and 0.45 ?, respectively, and that for the commercial hardware is 0.28 and 0.57 ?, respectively. The higher performance of the 3D printed reactor over the commercial hardware can be attributed to the microchannel design in the 3D printed reactor, which allows for enhanced heat and mass transport, facilitating the reaction inside the reactor.
Table 1: List of compounds analyzed in anolyte and catholyte by HPLC-MS.
Compounds in anolyte Compounds in catholyte
Vanillic acid Sinapic acid
Syringic acid Vanillin acetate
3,5-dimethoxy-4-hydroxyacetophenone
2-hydroxy-4-methoxyacetophenone
4-ethylcathecol
2,6-dimethoxyphenol
The list of chemicals determined by HPLC-MS is enlisted in Table 1
TECHNICAL ADVANCEMENTS
The present disclosure described herein above has several technical advantages including, but not limited to, the realization of a process for co-producing fine chemicals and hydrogen through lignin electrolysis, which:
? solves the problem of lignin waste disposal and the economical production of clean hydrogen.
? helps to treat large amounts of lignin waste and convert it into useful products owing to the continuous flow operation of the lignin electrolysis process.
? results in the simultaneous production of clean hydrogen from the lignin electrolysis, that can be utilized as fuel for electrical vehicles operated on fuel cells.
? intensifies the economically viable bio-conversion process using ambient temperature, cost-effective permeable electrodes, and semi-permeable separator, controllable flow of anolyte and catholyte without passivation of the anode and over oxidation of reactant species, that can improve the recovery of aromatic compounds as well as hydrogen production from lignin electrolysis.
? reduces the cost of hydrogen production owing to the co-production of fine chemicals.
? selectively separates compounds to the catholyte alongside the generation at the cathode, which results in ease of separation of the targeted compounds.
? is energy efficient, produces optimized yield, and enhances product separation.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. , Claims:WE CLAIM:
1. A process for co-producing fine chemicals and hydrogen, wherein said process comprises:
a. electrochemical oxidation of lignin at an anolyte in a reactor under a constant applied potential to obtain fine chemicals; and
b. separating said fine chemicals by selectively allowing to pass said fine chemicals through a semi-permeable separator to the catholyte in said reactor to obtain said fine chemicals and hydrogen.
2. The process as claimed in claim 1, wherein said process of electrochemical oxidation of lignin is a continuous flow process.
3. The process as claimed in claims 1 and 2, wherein said reactor comprises separator (1), cathode (2), anode (3), catholyte channels (4), anolyte channels (5), catholyte and hydrogen outlet (6), anolyte inlet (7), and anolyte and oxygen outlet (8).
4. The process as claimed in any of the claims 1 to 3, wherein said separator (1) is a proton or anion exchange semi-permeable separator.
5. The process as claimed in any of the claims 1 to 3, wherein said cathode (2), and said anode (3) are made of non-precious metals selected from iron, cobalt, nickel, copper, and stainless steel.
6. The process as claimed in any of the claims 1 to 4, wherein said anode and said cathode are separated by said separator (1).
7. The process as claimed in any of the claims 1 to 5, wherein said separator prevents mixing of anolyte and catholyte, wherein said anolyte comprising lignin and/or water, and wherein said catholyte is an alkaline solution with 1 to 10 molarity.
8. The process as claimed in any of the claims 1 to 7, wherein said anolyte comprising lignin in an alkaline solution with 10 to 50 wt% is inserted into said reactor through anolyte inlet (7).
9. The process as claimed in any of the claims 1 to 8, wherein said electrochemical oxidation of lignin is a continuous flow process, and the reaction time to reach the equilibrium is in the range of 20 hours to 40 hours for a reaction volume in the range of 400 mL to 3000 mL.
10. The process as claimed in any of claims 1 to 9, wherein vanillic acid, syringic acid, 3,5-dimethoxy-4-hydroxyacetophenone, 2-hydroxy-4-methoxyacetophenone, 4-ethylcathecol, and 2,6-dimethoxyphenol are obtained in anolyte, and wherein vanillin acetate and sinapic acid are obtained in catholyte.
11. The process as claimed in any of the claims 1 to 10, wherein said hydrogen is produced at said cathode (2).
12. A reactor for co-producing fine chemicals and hydrogen, by electrochemical oxidation of lignin as claimed in any of the claims 1 to 11, wherein said reactor comprises:
i. separator (1), cathode (2), anode (3), catholyte channels (4), anolyte channels (5), catholyte and hydrogen outlet (6), anolyte inlet (7), and anolyte and oxygen outlet (8);
ii. said separator (1) is a proton or anion exchange semi-permeable separator;
iii. wherein said cathode (2), and said anode (3) are made of non-precious metals selected from iron, cobalt, nickel, copper, and stainless steel;
iv. said anode and said cathode are separated by said separator (1) and prevent mixing of said anolyte and said catholyte; and
v. said separator selectively separates said fine chemicals to obtain vanillic acid, syringic acid, 3,5-dimethoxy-4-hydroxyacetophenone, 2-hydroxy-4-methoxyacetophenone, 4-ethylcathecol, and 2,6-dimethoxyphenol in anolyte, and wherein vanillin acetate and sinapic acid are obtained in catholyte.