"process of preparation of ethyl acetate by reactive chromatography"

Abstract

The present invention relates to a process of preparation of ethyl acetate by reactive chromatography The process includes a first stage of preparation of ethyl acetate by reactive chromatography and a second stage of regeneration of the catalyst. Further, the first stage includes a first step of filling a catalyst in the reaction vessel, a second step of maintaining temperature, a third step of adding reactants, a fourth step of sampling and analysis, and a fifth step of distillation; and the second stage includes a drying method and / or by a method of passing solvent for catalyst regeneration to restore the catalyst's activity for subsequent reactions. The process of the present invention offers energy efficiency, cost-effectiveness, and efficient processing, operates under moderate temperatures, simplifies catalyst separation, and improves production, scalability, and control for large- scale applications.

Description

[0001] “PROCESS OF PREPARATION OF ETHYL ACETATE BY REACTIVE CHROMATOGRAPHY”

[0002] FIELD OF THE INVENTION:

[0003] The present invention relates to a process of preparation of ethyl acetate and more particularly to a process of preparation of ethyl acetate by reactive chromatography.

[0004] BACKGROUND OF THE INVENTION:

[0005] Ethyl acetate (EtAc) is an important ester and has several applications in lacquers, varnishes, paints, extraction agents, solvents, and found in products such as nail polish, additives and printing inks. Ethyl acetate is a bulk chemical, and the worldwide demand is huge (~$5.12 billion in 2024). The Indian chemical industry also exports ethyl acetate (India exported worth $0,077 billion in 2023).

[0006] Considering the bulk requirement of ethyl acetate, there is always a need of the most suitable method for commercial and bulk production of ethyl acetate. Currently, there are four commercial processes to manufacture ethyl acetate: Acetaldehyde dimerization, Direct addition of ethylene to acetic acid, Dehydrogenation of ethyl alcohol (dimerization), and Fischer reaction of acetic acid with ethyl alcohol. There are certain benefits and drawbacks to each of the four methods.

[0007] Most esterification reactions have a range of equilibrium constant resulting into the post reaction mixture consisting of reactants as well as the formed products. Reactions require a catalyst: liquid catalysts like sulfuric acid, homogenized catalysts like p -toluene sulfonic acid and heterogeneous catalysts like clays, heteropolyacids, solid super acids and ion exchange resins (lERs).

[0008] The PCT Application WO2013079659A1 to Martin Nielsen and others discloses a process for producing ethyl acetate by dehydrogenation of ethanol in the presence of a ruthenium-based (Ru-based) homogeneous catalyst system comprising a tridentate pincer ligand and in presence of a base. However, the homogeneous catalyst is often irrecoverable after the reaction has run to completion. Thus, using homogeneous catalysis for industrial scale manufacturing processes is not as efficient or economically viable.

[0009] The PCT Application WO1998021173A1 to Tzong-Bin Lin and others discloses a process for the production of ethyl acetate from ethanol by oxidation of ethanol in the presence of a Pd catalyst, a metallic oxidation catalyst to form acetic acid and in the presence of excess liquid ethanol to absorb the acetic acid, allowing the acetic acid to react with the excess liquid ethanol to produce ethyl acetate and water, and removing ethyl acetate and water.

[0010] The PCT Application W02020256880A1 to Matthew S. IDE others discloses a rotating packed bed reactor that may be used to produce ethyl acetate from a carbonyl reactant such as acetic acid and ethanol. The production of ethyl acetate may be catalyzed by any suitable catalyst, such as metal catalysts including Pd, Ti, or Ru, or zeolites, or combination(s) thereof.

[0011] Though the reactions lead to improved process efficiency, the main downside of using metal catalysis is that the reaction conditions require high temperature and elevated pressure. The metals or metal oxides often cause leaching, reactor corrosion, and by-product formation. Additionally, metals such as palladium (Pd), platinum (Pt) are costlier than the rest of the other catalysts.

[0012] The US Patent Application US6765110B2 to R. Jay Warner and others discloses a process for the simultaneous coproduction and purification of ethyl acetate and isopropyl acetate. It produces ethyl acetate and isopropyl acetate by contacting acetic acid with a mixed alcohol stream of ethanol and isopropanol in the presence of an acidic catalyst in a liquid phase reaction system. Though acetate ester products with greater than 99.5 wt. % purity are obtained by this method, the separation of crude mixtures requires a series of three distillation towers.

[0013] A relatively simple reaction, the Fischer reaction produces minimal byproducts. The reaction mass from the Fischer reaction contains varying amounts of products and reactants, some of which form azeotropes. The post reaction separation involves a considerably longer downstream separation train.

[0014] Considering the azeotropic character of the system, the development of the downstream separation train requires a large inventory, as well as capital and operating expenditures, to be developed to an industrial scale due to the azeotropic nature of the system.

[0015] Additionally, catalyst regeneration and cleaning also raise the overall cost. Despite having a high demand, ethyl acetate is a bulk chemical that cannot be sold at a higher unit price because of its low margins, erratic demand, and susceptible markets. Therefore, lowering the total cost of production is required. Thus, it is necessary to reduce the overall production cost. There is a need for a process for the preparation of ethyl acetate production that overcomes the drawbacks of existing ethyl acetate production processes.

[0016] BRIEF DESCRIPTION OF DRAWINGS:

[0017] The objectives and advantages of the present invention will become apparent from the following description read in accordance with the accompanying drawings wherein,

[0018] FIG. 1 shows a reactive chromatography setup for the process of preparation of ethyl acetate in accordance with the present invention;

[0019] FIG. 2 shows outlet mass fraction from fixed bed chromatographic reactor in accordance with the process parameters disclosed in Example 1 of the present invention;

[0020] FIG.3 shows outlet mass fraction from fixed bed chromatographic reactor in accordance with the process parameters disclosed in Example 2 of the present invention;

[0021] FIG.4 shows outlet mass fraction from fixed bed chromatographic reactor in accordance with the process parameters disclosed in Example 3 of the present invention;

[0022] FIG.5 shows outlet mass fraction from fixed bed chromatographic reactor in accordance with the process parameters disclosed in Example 4 of the present invention;

[0023] FIGS. 6a and 6b indicate the separation of product from the reactant in the step of distillation disclosed in Example 5 of the present invention; and FIG. 7 shows outlet mass fraction from fixed bed chromatographic reactor obtained during catalyst regeneration step disclosed in Example 6 of the process of present invention.

[0024] SUMMARY OF THE INVENTION:

[0025] The present invention discloses a process of preparation of ethyl acetate by reactive chromatography. The process of preparing ethyl acetate includes a first stage of preparation of ethyl acetate by reactive chromatography and a second stage of regeneration of the catalyst by a drying method and / or a passing solvent for catalyst regeneration.

[0026] Further, the first stage of preparation of ethyl acetate by reactive chromatography includes a first step of filling the catalyst in the reaction vessel, a second step of maintaining temperature, a third step of adding reactants, a fourth step of sampling and analysis, and a fifth step of distillation.

[0027] In the first step, the reaction vessel is filled with the heterogeneous catalyst, i.e., Tulsion 63, followed by the addition of a first reactant that is acetic acid (99.9 mass %) to the point of saturating a column of the reaction vessel.

[0028] In the second step, the column is maintained at a predefined temperature of 50 - 75°C to ensure the reaction occurs at optimal conditions for efficient conversion.

[0029] In the third step, a predefined amount of a mixture containing the first and second reactants, such as acetic acid as the excess reactant and ethyl alcohol as the limiting reactant is added to pass over the saturated reaction bed, allowing the catalyst to facilitate the reaction between the reactants. In that the mixture of acetic acid and ethyl alcohol is added at a feed rate of 1-10 mL / min and then passed over the bed at different mole ratios ranging from 1: 1 to 10: 1 of acetic acid to ethyl alcohol.

[0030] In the fourth step, samples are collected from the resultant reaction mixture at regular intervals of time and then analysed to monitor the progress of the reaction.

[0031] In the fifth step, the resultant reaction mixture is subjected to distillation to separate the product ethyl acetate to allow for isolation and purification.

[0032] In the second stage of catalyst regeneration, the drying method includes the removal of the catalyst from the reaction vessel after the reaction is complete in the first stage, followed by drying the catalyst for a predefined period of 24 hours at a predefined temperature of 90 - 105 °C under vacuum.

[0033] Alternatively, in the second stage of catalyst regeneration, the method of passing the solvent for catalyst regeneration includes passing a predefined solvent, i.e., acetic acid, as the continuous phase through the reaction bed containing the catalyst at a predefined temperature of 70°C.

[0034] Further, the process of the present invention is carried out in a reactive chromatography setup in the liquid phase, and the amount of catalyst loading in the vessel is in volume between 50% and 80% of the total vessel volume.

[0035] DESCRIPTION OF THE INVENTION:

[0036] References in the specification to "one embodiment" or "an embodiment" means that a particular feature, structure, characteristic, or function described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.

[0037] References in the specification to “preferred embodiment” means that a particular feature, structure, characteristic, or function described in detail thereby omitting known constructions and functions for clear description of the present invention.

[0038] The foregoing description of specific embodiments of the present invention has been presented for purposes of illustration and description. These are not intended to be exhaustive or to limit the present invention to the precise forms disclosed and obviously many modifications and variations are possible in light of the above teaching.

[0039] Conventional preparation of ethyl acetate involves Fischer esterification between acetic acid (AcOH) and ethyl alcohol (EtOH) to produce ethyl acetate, that typically uses an acid catalyst as shown below:

[0040] Acetic acid Ethvl alcohol Ethyl acetate Water

[0041] Scheme 1: Esterification reaction of acetic acid and ethyl alcohol.

[0042] Although Fischer esterification uses an acid catalyst, such as sulphuric acid, to accelerate the reaction, it has disadvantages, including a reversible reaction, excess reagents, corrosion problems, environmental concerns, and energy consumption. Since it is an equilibrium reaction, high yields must be obtained by shifting the equilibrium, usually by applying excessive alcohol or by removing water. To further drive the reaction to completion, too much ethanol or acetic acid is employed, that results in waste and necessitates further energy-intensive separation and distillation processes to purify the final product.

[0043] Further, it is observed that the processes of the prior art very often utilizes reactive distillation (RD) to overcome equilibrium limitations. However, it requires vapor phase reaction, high energy, high temperatures, and expensive catalysts. The present invention describes an improved process to prepare ethyl acetate using reactive chromatography to overcome the drawbacks mentioned in the art.

[0044] In the process of the present invention, ethyl acetate is prepared by Fischer esterification carried out in the liquid phase at moderate temperature and atmospheric pressure in the presence of a heterogeneous catalyst (acidic ion exchange resin) to avoid challenges of conventional processes. Due to the heterogeneous nature of the catalyst, its separation is easier. Since the reaction is carried out in the liquid phase, problems associated with vapour phase reactions are circumvented. Further, the incorporation of reactive chromatography (RC) in the process of the present invention eliminates the need for high temperatures while also reducing the burden on downstream separation. RC offers better control over the reaction and separation processes, potentially improving selectivity and yield of the final product, i.e., ethyl acetate (99.92 mass %). Additionally, the process of RC of the present invention differs from prior art processes in terms of its vapour- liquid equilibrium. Further, in the present invention, the reaction mass comprises only two components, namely, acetic acid and ethyl acetate. Their boiling points are: 118°C and 78°C respectively.

[0045] Additionally, the process of the present invention employs acetic acid as an excess reactant, while ethyl alcohol is provided in a stoichiometric amount as the limiting reactant in contrast to traditional Fischer esterification. Alcohol is therefore absent from the reaction mass once the limiting reactant, ethyl alcohol, is quantitatively converted to the point where the output reaction mass is nearly free of the limiting reactant. The absence of the alcohol-related azeotropes makes the process of the present invention very advantageous as it minimizes the load on distillation.

[0046] Furthermore, the generated water is adsorbed on the catalyst resin due to its great affinity, leaving the reaction mixture nearly water-free. Thus, unreacted acetic acid produces ethyl acetate, and extremely little, insignificant amounts of ethyl alcohol and water that constitutes the final reaction mixture. Hence, only one downstream distillation column is needed; thus reducing the operational costs.

[0047] Now, a preferred process (100) of preparing ethyl acetate by reactive chromatography (herein after referred to as “process 100”) in accordance with the present invention is described.

[0048] The process (100) of preparing ethyl acetate by reactive chromatography includes a first stage (101) of preparation of ethyl acetate by reactive chromatography in a reactive chromatography setup as described in Figure 1 and a second stage (201) of regeneration of the catalyst utilised in the process (100). In the first stage (101), ethyl acetate is synthesized by a reaction between ethanol and acetic acid. This reaction is facilitated by a catalyst in a chromatography column where reaction and separation occur simultaneously. Reactive chromatography combines the benefits of both catalytic reactions and separation processes, allowing efficient production of ethyl acetate.

[0049] The second stage (201) involves regenerating the catalyst. During the process (100), the catalyst might degrade or lose its activity over time due to fouling, poisoning, or other reasons. Regeneration is carried out to restore the catalyst's effectiveness for continued use in the reaction. It is carried out either by drying the catalyst to remove moisture and volatile compounds or by passing a solvent to remove chemicals and impurities and restore its catalytic properties.

[0050] In accordance with the process (100) of the present invention, the first stage (101) includes the following steps: a. filling the reaction vessel with a catalyst (110), b. maintaining temperature (120), c. adding reactants (130), d. sampling and analysis (140), and e. distillation (150).

[0051] The first step of filling catalyst in the reaction vessel (110) includes filling a reaction vessel with the catalyst, followed by the addition of a first reactant to the point of saturating a column of the reaction vessel. The second step of maintaining temperature (120) includes maintaining the column at a predefined temperature to ensure the reaction occurs at optimal conditions for efficient conversion.

[0052] The third step of adding reactants (130) includes adding a predefined amount of a mixture containing the first and second reactants. This mixture is carefully introduced to pass over the saturated reaction bed, allowing the catalyst to facilitate the reaction between the reactants.

[0053] The fourth step of sampling and analysis (140) includes collecting samples from the resultant reaction mixture at regular intervals of time for analysis, and these samples are then analysed to monitor the progress of the reaction and determine the composition of the product.

[0054] The fifth step of distillation (150) includes subjecting the resultant reaction mixture to distillation. The process of distillation separates the ethyl acetate from any other by-products, allowing for isolation and purification of the desired product.

[0055] In this preferred embodiment, the first reactant is acetic acid (99.9 mass %). The column is maintained at a predefined temperature of 50 - 75°C. The second reactant is ethyl alcohol. The catalyst is Tulsion 63 (acid ion exchange resin). The mixture of acetic acid and ethyl alcohol is added at a feed rate of 1-10 mL / min and is passed over the bed at different mole ratios ranging from 1: 1 to 10: 1 of acetic acid to ethyl alcohol. Further, in this embodiment, the resultant reaction mixture is subjected to distillation till the point where the reactant and the product are separated, that is, in less than one hour. In accordance with the process (100) of the present invention, the second stages (201) of regenerating the catalyst by either of the two methods are mentioned below to restore the catalyst’s activity for subsequent reactions.

[0056] 1. a drying method / or

[0057] 2. by passing solvent for catalyst regeneration.

[0058] The drying method includes the catalyst being removed from the reaction vessel after the reaction is complete in the first stage (101). The catalyst is then dried for a predefined period of time at a predefined temperature under vacuum. The method ensures the removal of residual materials accumulated during the reaction, restoring the catalyst's activity.

[0059] The method of passing solvent for catalyst regeneration involves passing a predefined solvent through the reaction bed containing the catalyst at a predefined temperature. The solvent helps remove the chemicals or by products that have adhered to the catalyst to ensure effective cleaning and regeneration of the catalyst.

[0060] Further, in the step of catalyst regeneration by the drying method, the predefined period of time is 24 hours, and the predefined temperature is 90 - 105 °C. The predefined solvent in the passing solvent for catalyst regeneration is the first reactant, i.e., acetic acid, as the continuous phase at a predefined temperature of 70°C.

[0061] Acetic acid is used as an excess reactant with ethyl alcohol fed in stoichiometric proportion, wherein almost quantitative conversion of limiting reactant is achieved so that the outlet reaction mass is almost free of limiting reactant viz. ethyl alcohol. Due to the strong affinity of the formed water, it gets adsorbed on the catalyst resin, and the reaction mixture is almost free of water also. Thus, the reaction mixture comprises unreacted acetic acid, formed ethyl acetate, and negligible amounts of ethyl alcohol and water. Increase in the catalyst concentration improves conversion to 100%, also simultaneously adsorbing the formed water.

[0062] Ethyl alcohol is selected as the limiting reactant, thus making acetic acid the excess reactant. When quantitative conversion of the limiting reactant (viz., ethyl alcohol) is realised, then the alcohol is not present in the reaction mass. This is quite beneficial because the azeotropes involving the alcohol will not be present. Distillation, or Reactive Distillation (RD), is beneficial if complete conversion of the limiting reactant is achieved. In an RD setup, due to boiling and vaporisation, temperature is increased. Some alcohol evaporates without much reaction; this makes the conversion less than 100%, although conversion is more than conventional reactors and is also more than the equilibrium value.

[0063] Referring to FIG. 1, a process of the present invention takes place in a reactive chromatography setup wherein a chemical reaction occurs simultaneously with the separation of components within the column.

[0064] Now, in accordance with the reactive chromatography system used in the present invention, the vessel material and design are described. The system vessel is made of specialty-grade stainless steel to withstand the corrosive nature of chemicals. The vessel is equipped with valves at the inlet and outlet that are included for precise control. Further, thermocouples are placed at both ends of the vessel to monitor temperature during reaction. The reaction vessel is installed horizontally or vertically or even at an angle to horizontal but is preferably mounted vertically. A high-precision metering pump is used to feed reactants into the reactor at a specific rate.

[0065] In this preferred embodiment, a column composition is described. The column comprises of a cylindrical reactive vessel, having an inner diameter between 0.5 and 1 inch and a height between 0.5 and 2 feet. The catalyst is supported on glass beads. Their primary function is probably to ensure that the catalyst is distributed evenly and steadily throughout the column. The amount of catalyst loaded in the vessel is 40 g. The catalyst volume is between 50% and 80% of the total vessel volume.

[0066] EXAMPLES:

[0067] A few examples and implementations are disclosed. Variations, modifications, and enhancements to the described examples and implementations and other implementations can be made based on what is disclosed.

[0068] Examples are set forth herein below and are illustrative of different amounts and types of reactants and reaction conditions that can be utilized in practicing the disclosure. It will be apparent, however, that the disclosure can be practiced with other amounts and types of reactants and reaction conditions than those used in the examples, and the resulting devices various different properties and uses in accordance with the disclosure above and as pointed out hereinafter.

[0069] EXPERIMENTAL SECTION: Example 1 (Run 1):

[0070] A reactive chromatography run was conducted with the conditions: mole ratio: 1: 1, feed rate: 2 mL / min, catalyst loading: 40 g, temperature: 60°C (Figure 2). An average conversion of 94.6% based on ethyl alcohol was achieved in 1.75 hours (105 minutes), wherein the outlet stream was seen to consist of only acetic acid and ethyl acetate with almost non-existing amounts of water and ethanol. All the formed water and unreacted remaining ethyl alcohol was adsorbed on the catalyst surface; hence, it did not appear in the outlet stream for the first 1.75 hours of reaction. With increasing time, the conversion also dropped, and the outlet stream contained increasing amounts of water, ethyl alcohol, and acetic acid and decreasing amounts of ethyl acetate. Thus, collectively at up to 1.75 hours, the outlet contained 43.2% ethyl acetate and 56.7% acetic acid with water and ethyl alcohol combined constituting about 0.1 mass%. Obviously, this is a better option for separation. Just for comparison, at 2.25 hours, water was approximately 6.8%, ethyl alcohol around 4.0%, acetic acid around 42.8%, and 46.45% ethyl acetate by mass.

[0071] Example 2 (Run 2):

[0072] A reactive chromatography run was conducted with the conditions (Figure 3): Mole ratio: 1: 1, feed rate: 1 mL / min, catalyst loading: 40 g, temperature: 70°C. An average conversion of 96% based on ethyl alcohol was achieved in a time up to 1.75 hours (105 minutes). In the same period, the outlet stream was seen to consist of only 43.60% acetic acid and 56.39% ethyl acetate with almost non-existent amounts of water and ethyl alcohol. At 2.25 hours, water was approximately 1.26%, ethyl alcohol around 6.83%, acetic acid around 30.85%, and 61.04% ethyl acetate. Example 3 (Run 3):

[0073] A reactive chromatography run was conducted with the conditions: mole ratio (ethyl alcohol: acetic acid): 1:2, feed rate: 2 mL / min, catalyst loading: 40 g, temperature: 70°C (Figure 4). An average conversion of 97% based on ethyl alcohol was achieved in a time up to 1.75 hours (105 minutes). In the same period, the outlet stream was seen to consist of only 45.31% acetic acid and 54.33% ethyl acetate with an almost non-existent amount of water and ethanol.

[0074] Example 4 (Run 4):

[0075] A reactive chromatography run was conducted with the conditions: mole ratio (ethyl alcohol: acetic acid): 1:3, feed rate: 2 mL / min, catalyst loading: 40 g, temperature: 70°C (Figure 5). An average conversion of 99% based on ethyl alcohol was achieved in a time up to 1.75 hours (105 minutes). In the same period, the outlet stream was seen to consist of -55% acetic acid and 45% ethyl acetate by mass with an almost non-existent amount of water and ethanol.

[0076] Example 5: Distillation

[0077] A reboiler (0.0038 m3- 3.8 L - capacity) with a heating arrangement served as the base for the distillation setup as shown in Figure 1. A 1 m glass column (51 mm ID) encased the Flyflux distillation packings that are well-known knitted wire mesh packings with a faster mass transfer rate and good separation efficiency. The packing’s are made of SS 316 L, with a maximum surface area of 1200 m2 / m3, a HETP of 0.075 m, made of SS 316 L. A condenser and Dean and Stark assembly with 800 mL capacity was used. Before distillation, water was removed by selective adsorption over 3A molecular sieves (MS, 1 / 16-inch pellets, SD Fine Chem. Ltd.,

[0078] India) whenever a detectable amount of water was present.

[0079] Distillation of the reaction mass from run 1 mentioned above (43.2% ethyl acetate and 56.7% acetic acid) was conducted. It was seen that in less than one hour the two components separated into almost pure streams (Figures 6a and 6b), viz., acetic acid (99.96 mass %) and ethyl acetate (99.92 mass %). The dotted lines notify the trace of mass % (Figure 6a) and temperatures (Figure 6b) do not indicate continuous points. Reaction mass from all the remaining runs was subjected to distillation to verify the presumption that simple distillation can easily separate the reaction mass into pure components. These results confirmed that the intended separation is feasible, as indicated in Table 1.

[0080] Table 1: Results of Distillation experiments

[0081] Run Distillate (EtAc), Bottom

[0082] Mass % (AcOH),

[0083] Mass %

[0084] Run 2 (43.60 and 56.40 mass % AcOH 99.99 99.98 and EtAc)

[0085] Run 3 (45.32 and 54.68 mass % AcOH 99.99 99.98 and EtAc)

[0086] Run 4 (55 and 45 mass % AcOH and 99.99 99.98

[0087] EtAc) Example 6: Catalyst regeneration

[0088] Regeneration of the catalyst is achieved in the following manner:

[0089] Method 1: Drying the catalyst after taking it out of the reaction vessel. Method 2: Passing a solvent to remove the chemicals on the catalyst.

[0090] Method 1:

[0091] The catalyst was removed after the reaction, and it was dried for 24 hours between 90 and 105°C under vacuum. The catalyst mass was found to be almost the same as initially taken for the run. The catalyst activity was checked by conducting the run that was previously conducted (mole ratio: 1: 1, feed rate: 1 mL / min, catalyst loading: 40 g, temperature: 70°C). The results were verified, and it was found that almost similar results were obtained on repeating.

[0092] Method 2:

[0093] Acetic acid was used as the continuous phase. First, a run was conducted (Figure 3, mole ratio: 1: 1, feed rate: 1 mL / min, catalyst loading: 40g, temperature: 70°C). After the reaction was over, the pure acetic acid stream was passed over the bed at 70°C. Outlet samples were continuously collected, and the composition was plotted against time (Figure 7). It was seen that complete regeneration of the bed is achieved. Almost pure acetic acid was obtained after ~2.5 hours. In order to verify that the catalyst bed was really regenerated, a run was again carried out (mole ratio: 1: 1, feed rate: 1 mL / min, catalyst loading: 40g, temperature: 70°C), and a similar result was obtained as previously obtained.

[0094] Advantageously, the process (100) of the present invention offers several key benefits, including energy efficiency, cost-effectiveness, and efficient processing. As the process (100) operates under moderate temperatures and atmospheric pressure, it eliminates the need for higher temperatures, improves conversion and yield, and simplifies catalyst separation. The continuous process simplifies production, increases consistency, and improves scalability and control. Additionally, non-azeotropic distillation simplifies product and reactant separation, preventing complications. These advantages make the process suitable for large- scale applications.

[0095] The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others, skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated.

[0096] It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.

Claims

Claims:

1. A process (100) of preparing ethyl acetate comprising: a. a first stage (101), including preparation of ethyl acetate by reactive chromatography, wherein the first stage (101) includes a first step (110) of filling a catalyst in the reaction vessel, a second step (120) of maintaining temperature, a third step (130) of adding reactants, a fourth step (140) of sampling and analysis, and a fifth step (150) of distillation; and b. a second stage (201), including regeneration of the catalyst, by a drying method and / or by passing solvent for catalyst regeneration.

2. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein in the first stage (101), the first step (110) includes filling a reaction vessel with the catalyst, followed by the addition of a first reactant, acetic acid (99.9 mass %), to the point of saturating a column of the reaction vessel.

3. The process (100) of preparing ethyl acetate as claimed in claim 2, wherein the catalyst being the heterogeneous catalyst, Tulsion 63.

4. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein in the first stage (101), the second step (120) of maintainingtemperature includes maintaining the column at a predefined temperature of 50 - 75°C to ensure the reaction occurs at optimal conditions for efficient conversion.

5. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein in the first stage (101), the third step (130) of adding reactants includes a predefined amount of a mixture including the first reactant and a second reactant, wherein the first reactant being acetic acid as the excess reactant and the second reactant being ethyl alcohol as the limiting reactant, being added to pass over the saturated reaction bed, allowing the catalyst to facilitate the reaction between the reactants.

6. The process (100) of preparing ethyl acetate as claimed in claim 5, wherein in the third step (130), a mixture of acetic acid and ethyl alcohol being added at a feed rate of 1-10 mL / min and then passed over the bed at different mole ratios ranging from 1: 1 to 10:1 of acetic acid to ethyl alcohol.

7. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein in the first stage (101), the fourth step (140) of sampling and analysis includes collecting samples from the resultant reaction mixture at regular intervals of time for analysis, and these samples being then analysed to monitor the progress of the reaction.

8. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein in the first stage (101), a fifth step (150) of distillation includes subjecting the resultant reaction mixture to distillation to separate the product ethyl acetate from any other by-products, allowing for isolation and purification.

9. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein the second stage (201) of catalyst regeneration by the drying method includes removal of the catalyst from the reaction vessel after the reaction being complete in the first stage (101) followed by drying the catalyst for a predefined period of 24 hours at a predefined temperature of 90 - 105 °C under vacuum.

10. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein the second stage (201) of catalyst regeneration by the method of passing solvent for catalyst regeneration includes passing a predefined solvent, i.e., acetic acid, as the continuous phase through the reaction bed containing the catalyst at a predefined temperature of 70°C.

11. The process (100) of preparing ethyl acetate as claimed in claim 1, wherein the process (100) being carried out in a reactive chromatography setup in the liquid phase, wherein the amount of catalyst loading in the vessel being in volume between 50% and 80% of the total vessel volume.

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