Gamma-lactone recovery process

Abstract

A method of forming gamma valerolactone (GVL) includes contacting a mixed feed stream comprising unreacted 3-pentenenitrile (3PN) and water within a first reactor in the presence of a heterogeneous catalyst. The reaction can occur at a temperature range of 100°C to 400°C and under a pressure of 150 pounds per square inch (psi) or less. The method involves separating unreacted 3PN and water from the GVL product, then routing these unreacted components back to the first reactor for further GVL formation.

Description

Docket No. INV-24031-WO-PCTGAMMA-LACTONE RECOVERY PROCESSCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 723,602 filed Nov. 22, 2024, the disclosure of which is incorporated herein in its entirety by reference.BACKGROUND

[0002] Cyclic esters, such as lactones, are useful chemical intermediates in a variety of applications. For example, Gamma Valerolactone (GVL), can be used as a biofuel, as a solvent, in the manufacture of certain polymeric membranes, and in some cases as a fragrance.SUMMARY OF THE INVENTION

[0003] Various aspects of the present disclosure provide a method of forming gamma valerolactone (GVL). The method includes contacting, within a reactor, a mixed feed stream including a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of 7 atmosphere or less, whereby GVL is formed. The method includes separating, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water. The method also includes routing the second stream of any unreacted 3PN and the second stream of unreacted water to the reactor whereby further GVL is formed.

[0004] Various aspects of the present disclosure provide a system for forming gamma valerolactone (GVL). The system includes a first reactor configured to contact a mixed feed stream including a first stream of unreacted 3-pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of 7 atmosphere or less such that GVL is formed. The system includes one or more columns configured to separate, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water. The system also includes a recycling circuit configured to route the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor such that further GVL is formed.

[0005] Various aspects of the present disclosure provide a system for forming gamma valerolactone (GVL). The system includes a reactor for contacting, within a first reactor, aDocket No. INV-24031-WO-PCT mixed feed stream including a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of 7 atmosphere or less, such that GVL is formed. The system includes a separator for separating, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water. The system also includes a conduit for routing the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor such that further GVL is formed.

[0006] In various aspects of the present disclosure, a process for forming gamma valerolactone (GVL) can involve utilizing 3 -pentenenitrile (3PN) as a starting material. The process can commence by contacting a mixed feed stream including unreacted 3PN and water within a first reactor. A chemical reaction can be induced in the presence of a heterogeneous catalyst, which may include a solid acid catalyst, a metallic catalyst, an acid, or a combination thereof. For example, the reaction can be induced at a temperature within a range of 100°C to 400°C and under a pressure of 10 atm or less, such as within a range of 1 atm to 7 atm. The mixed feed stream can include a molar ratio of water to 3PN within a range of 1 : 1 to 20: 1.

[0007] Prior to entering the reactor, the mixed feed stream can be preheated and at least partially vaporized. For example, the reactor itself can include an initial vaporizer and preheater section to ensure the entire stream is in the gas phase and at the desired reaction temperature. Within the reactor, 3PN can undergo hydrolysis with water followed by lactonization (or ring closure) to form the desired product, gamma-valerolactone. Such a reaction can produces ammonia as a byproduct, originating from the nitrile group in the 3PN.

[0008] After the reaction, the effluent stream from the reactor can undergo a series of separation steps to isolate the GVL product and recycle unreacted materials. For example, the effluent stream can be cooled and fed to a first distillation column to remove the ammonia byproduct. The bottom stream from the first distillation column, now substantially free of ammonia, can be fed to a second column for further separation. In the second column, the desired lactone product and near-boiling intermediates can be concentrated in a bottom stream, while excess water and unreacted 3PN can be recovered in the overhead stream. The overhead stream can undergo phase separation, e.g., resulting in a water-rich stream and an organic-rich stream, both of which can be recycled back to the reactor. The bottom stream from the second column, enriched in GVL and reaction intermediates, can undergo further refinement in a third column. Here, the crude GVL product can be obtained as the bottomDocket No. INV-24031-WO-PCT stream, while reaction intermediates, including 3 -pentenoic acid, concentrate in the overhead stream.

[0009] An optional step in the process involves further processing of the reaction intermediates. For example, the overhead stream from the third column, containing compounds like 3 -pentenoic acid, can be reacted with additional water in a second reactor to produce additional GVL. In an example, the crude GVL product can undergo a final purification step in a fourth column, where high-purity GVL (99.99% or greater) is obtained as the overhead product.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In the drawings, which are not necessarily drawn to scale, like numerals can describe similar components in different views. Like numerals having different letter suffixes can represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present document.

[0011] FIG. l is a schematic diagram of an example of a system for forming gamma valerolactone (GVL)

[0012] FIG. 2 is a schematic diagram of an example of a system for forming gamma valerolactone (GVL)DETAILED DESCRIPTION OF THE INVENTION

[0013] One approach to preparing Gamma-valerolactone (GVL) involves levulinic acid via a hydrogenation process. Such a hydrogenation process can involve conditions such as a relatively high pressure (about 100 atm) and heat (e.g., about 200-250°C). Levulinic acid is a bio-based feedstock, e.g., derived from cellulose. Production of GVL via the hydrogenation of levulinic acid can be undesirable for certain reasons, such as based on the challenges of being relatively energy intensive and expensive. The present inventors have recognized the benefits of an alternative way to produce GVL, not requiring any bio-based feedstock and able to be produced with considerably less energy and involving lower pressures.

[0014] The present disclosure describes in various aspects a method for forming GVL using 3 -pentenenitrile (3PN) as the starting feed material. The method involves relatively low pressures (e.g., within a range of about 1 atm to about 7 atm) and does not require any hydrogenation. The method can involve lower product carbon footprint for GVL compared to the bio-derived process involving hydrogenation. An important intermediate in nylon 66Docket No. INV-24031-WO-PCT manufacture, hexamethylenediamine (HMD), can be industrially produced by hydrogenating a six-carbon linear dinitrile, commonly known as adiponitrile (ADN). In an example, the 3PN stream can be collected from an adiponitrile (ADN) manufacturing process. For example, adiponitrile can be synthesized from a double hydrocyanation reaction between butadiene and a cyanide source. This process chemistry can generate a mixture of various mono-nitriles, including 3 -pentenenitrile (3PN) and 2-pentenenitrile (2PN), such as during an initial hydrocyanation step.

[0015] In an example, the technique can involve a series of separation stages to separate and recycle any unconverted 3PN, following a hydrolysis step, toward a reactor such as to promote further conversion of 3PN to GVL. For example, the technique can involve isomerizing reaction intermediates, e.g., produced during an initial hydrolysis process from other components present in the 3PN stream (e.g. 2PN), to GVL, thereby increasing a total GVL yield. The technique can also involve producing ammonia as a byproduct that can be recovered and used in other applications.

[0016] The hydrolysis of the 3PN can be carried out within a reactor and in the presence of a heterogeneous catalyst under moderate pressure conditions. The technique can involve first separating out any byproducts and unconverted reactants, then recycling the unconverted reactants back to the reactor, and producing GVL as a final product. For example, the GVL can be produced with a product purity of up to 99.9 weight percentage (wt%).

[0017] Methodologies described herein can be performed on a system or apparatus, e.g., including a series of components such as reactors, distillation columns, phase separators, heat exchangers, pumps, and recycle streams. For example, the system or apparatus can involve a multistage process to induce a separation of products, intermediates, and unreacted reactants. The system or apparatus can be configured such as to control several operating conditions (flow rates, pressure, temperature, recycle-to-feed ratios, purge rates) according to specified parameters to promote the hydrolysis and lactonization of 3PN to produce the GVL.

[0018] FIG. l is a schematic diagram of an example of a system for forming gamma valerolactone (GVL)

[0019] In FIG. 1, stream 101 is a combination of two independent streams — water and 3PN. The 3PN stream can have a 3PN concentration greater than about 85 weight percentage (wt%) with the balance being 2PN. Stream 101 can enter the fluid circuit at a temperature close to the ambient temperature and at a pressure ranging from about 1 atm to about 7 atm.

[0020] Stream 101 can be mixed with two recycle streams, such as stream 111 and 112.Stream 111 can include a water-rich (e.g., heavier) phase and stream 112 can include a 3PNDocket No. INV-24031-WO-PCT rich (e.g., organic) stream. The resultant mixed feed stream 102 can be a biphasic (e.g., two- liquid phases) mixture. Stream 102 can include a water-to-3PN molar ratio within the range of about 1 : 1 to about 20: 1. For example, stream 102 can include a water-to-3PN molar ratio of about 3 : 1 to about 5: 1.

[0021] In an example, stream 102 can be preheated by heat-exchange in a feed preheater 110. Depending on the heat input, the resulting hot feed stream 103 can be a vapor liquid or a vapor-liquid-liquid mixture. The feed preheater 110 can be heat-integrated with a reactor effluent cooler 130 or can be an independent heat exchanging device. As depicted FIG. 1, a dotted heat exchange stream HX1 represents an arrangement when the feed preheater 110 and the reactor effluent cooler 130 are heat integrated together meaning they are the same unit. In this arrangement, the hot reactor effluent stream 104 serves as a heating medium to preheat the feed stream 102.

[0022] The preheated stream 103 can flow into a reactor 120. The reactor 120 can include an initial vaporizer and a preheater section configured for vaporizing the stream into a gas phase and preheating the stream to the reactor temperature. The reactor operating temperature can be within the range of about 100°C to about 400°C. The reactor may be a catalyst packed bed and may be operated with a downward flow of the reactants in the bed. The residence time of the reactants may range from about 30 seconds (s) to about 60 minutes (min).

[0023] The reactor effluent stream 104 exiting the reactor 120 can be cooled and at least partially condensed into a cooled reactor effluent mixture stream 105 in the reactor effluent cooler 130 that can be directly heat integrated with the mixed feed stream 102. For example, the heat content of the reactor effluent stream 104 can be heat-exchanged to preheat the mixed feed stream 102.

[0024] The cooled reactor effluent stream 105 can be fed at or near a top section of a first column 140 to remove any ammonia generated from the reaction. In an example, the first column 140 can be equipped with an overhead condenser and a bottom reboiling unit. The first column 140 can have at least 5, such as at least 10, at least 12, or at least 15 theoretical stages and operated at a specified pressure, the specified pressure selected such that the overhead condenser temperature is approximately in the range of 4°C to 10°C. In an example, a pressure in the overhead condenser pressure can be controlled at or near about 22 psia. The vapor stream obtained from the overhead condenser can have a concentrated ammonia stream 107. The first column bottom stream 106 can contain less than 100 parts per million (ppm) by weight of ammonia.Docket No. INV-24031-WO-PCT

[0025] The first column bottom stream 106 can be fed toward a second column 150. The stream 106 can be further distilled and separated into a two-phase liquid mixture 109 at the top and the second column bottom stream 108 rich in the desired reaction product, such as including primarily a lactone along with other near-boiling side-products. The second column 150 can have at least 5, such as at least 10, at least 12, or at least 15 theoretical stages. The second column overhead condenser can be operated at or near atmospheric pressure and the stream 106 can be fed toward the top of the second column 150. Any excess water, 3PN, or other generated low-boiling byproducts from the reactor 120 can be concentrated in the second column overhead stream 109. The overhead condenser of the second column 150 can be, e.g., a partial or a total condenser. As depicted in FIG. 1, stream 109 represents the combined flow of both the vapor and liquid distillate exiting the overhead condenser.

[0026] The second column overhead stream 109 can be separated into two phases in a phase separator 160. The phase separator 160 can provide adequate residence time for the stream 109 to undergo phase separation at the operating conditions. For example, the phase separator 160 can be a gravity settler, a decanter or combination of settler and a centrifuge. The phase separator 160 can split the stream 109 into a water-rich, heavier stream 111 and an organic-rich, lighter stream 112. Any non-condensable components can also be separated in the phase separator 160 and discharged via an offgas steam 113. Up to about 20%, such as up to about 10% (by weight) of the aqueous phase 111 can be purged such as to avoid buildup of any undesired contaminants in the aqueous stream 111. Similarly, an organic stream 112 purge can be included such as to minimize buildup of any organic contaminants in the organic stream 112. Both, the organic stream 112 and the aqueous stream 111 can be recycled back to the reactor feed mixer Ml . The mixer Ml can be an intermediate feed collection tank, a storage vessel, or a pipeline flow mixing device during the continuous operation.

[0027] The second column 150 bottom stream 108 can be fed at or near a mid-section (e.g., at or near a vertical midline) of a third column 170. The second column bottom stream 108 can be enriched with a desired reaction product along with some high boiling fraction and certain hydrolysis reaction intermediates (e.g. 3-pentenoic acid). In the third column 170, the stream 108 can be separated into a reaction intermediates stream 115, while the desired lactone product can be concentrated at the column bottom as the crude product stream 114. The third column 170 can have at least 10, such as at least 12, at least 15, or at least 20 theoretical stages and can be operated under relatively low pressure (e.g., within a range ofDocket No. INV-24031-WO-PCT about 0.05 atm to about 1 atm) and at the temperature within the range of about 120°C to about 220°C. About 80% to about 90% of the separated intermediate stream 115 can be pumped back to mixer Ml and the remainder of the stream 115 can be purged to minimize and control the impurity levels.

[0028] The crude lactone product stream 114 exiting the third column 170 can be fed near the mid-section of a fourth column 180 for product purification. The fourth column 180 can provide further separation such as to purify the desired product in the overhead stream 116. The fourth column bottom stream 117 can include high-boiling components that can be purged or otherwise routed for disposal. The fourth column 180 can have at least 10, such as at least 12, at least 15, or at least 20 theoretical stages and can be operated at a relatively low pressure (e.g., within a range of about 0.05 atm to about 1 atm) and at the temperature within a range of about 120°C to about 280°C.

[0029] FIG. 2 shows a schematic representation of an aspect 200 according to the present disclosure.

[0030] In FIG. 2, stream 201 can include a combination of two independent streams, e.g., water and 3PN. The 3PN stream can have a 3PN concentration greater than 85 wt% with the balance being 2PN. Stream 201 can enter the process at a temperature at or near a temperature of the ambient environment and at or near a pressure within a range of about 1 atm to about 7 atm.

[0031] The stream 201 can be mixed with two recycle streams, e.g., stream 211 and 212. Stream 211 can include a water-rich (e.g., heavier) phase and stream 212 can include a 3PN rich (e.g., lighter) stream. The resultant stream 202 can be a biphasic (e.g., two-liquid phases) mixture. Stream 202 can have a water-to-3PN molar ratio in the range from 1 : 1 to 20: 1. In an example, a water-to-3PN molar ratio of 3 : 1 to 5 : 1 can be used in the process.

[0032] Stream 202 can be preheated by heat-exchange in feed preheater 210. The resulting hot feed stream 203 can be a two-phase vapor liquid or a three-phase vapor-liquid-liquid mixture, depending on an amount of the heat input. The feed preheater 210 can be heat- integrated with a reactor effluent cooler 230 or can be an independent heat exchanging device. As shown in FIG. 2, a dotted heat exchange stream HX2 represents an arrangement when the feed preheater 210 and the reactor effluent cooler 230 are heat integrated together. In this arrangement, the hot reactor effluent stream 204 serves as a heating medium to preheat the feed stream 202.

[0033] The preheated stream 203 can be flowed into a reactor 220. The reactor 220 can include an initial vaporizer and a preheater section that vaporizes the entire stream into a gasDocket No. INV-24031-WO-PCT phase and preheats the stream to the reactor temperature. The reactor operating temperature can be within the range of about 100 degrees Celsius (°C) to about 400°C. The reactor can include a catalyst packed bed and can be operated, e.g., with a downward flow of the reactants in the bed. The residence time of the reactants can range from about 30 seconds (s) to about 60 minutes (min).

[0034] In an example, the reactor effluent stream 204 exiting the reactor 220 can be cooled and partially condensed into a cooled reactor effluent mixture stream 205 in the reactor effluent cooler 230. For example, the effluent cooler 230 can be directly heat-integrated with the mixed feed stream 202. In an example, the heat content of the reactor effluent stream 204 can be heat-exchanged to preheat the mixed feed stream 202.

[0035] The cooled reactor effluent stream 205 can be fed at or near a top section of a first column 240 such as to remove any ammonia generated from the reaction. In an example, the first column 240 can be equipped with an overhead condenser and a bottom reboiling unit. The first column 240 can be operated at a pressure such that the overhead condenser temperature is approximately in the range of about 4°C to 10°C. In an example, the overhead condenser pressure can be maintained to approximately 22 psia. The vapor stream obtained from the overhead condenser can have a concentrated ammonia stream 207. The first column bottom stream 206 can contain less than 100 ppm (by wt.) of ammonia.

[0036] The first column bottom stream 206 is fed to a second column 250. The stream 206 is further distilled and separated into a two-phase liquid mixture 209 at the top and the second column bottom stream 208 rich in the desired reaction product, such as primarily including a lactone along with other near-boiling byproducts. The second column 250 can include at least 5 stages, such as about 10 stages, about 12 stages, or about 15 theoretical stages. The second column overhead condenser can be operated at or near an atmospheric pressure and can have at least 5 stages, such as about 10 stages, about 12 stages, about 15 stages, or about 20 stages. The stream 206 can be fed close to the top of the second column 250. The excess water, 3PN, and other generated low-boiling byproducts from the reaction 120 can be concentrated in the second column overhead stream 209. The overhead condenser of the second column 250 may either be a partial or a total condenser. As depicted in FIG. 2, the stream 209 can represent a combined flow of both the vapor and liquid distillate exiting the condenser.

[0037] The second column overhead stream 209 can be separated into two phases in a phase separator 260. The phase separator 260 can provide a desired residence time for the stream 209 to undergo phase separation at specified operating conditions. For example, the phaseDocket No. INV-24031-WO-PCT separator 260 can include a gravity settler, a decanter, or combination of settle and a centrifuge. The phase separator 260 can split the stream 209 into a water-rich, heavier stream 211 and an organic-rich, lighter stream 212. Any non-condensable components can also be separated in the phase separator 260 and discharged as an off-gas stream 213. Up to 10%- 20% (by wt.) of the aqueous phase 211 can be purged such as to avoid buildup of any undesirable contaminants in the aqueous stream 211. Similarly, an organic stream 212 purge can be taken to minimize buildup of any organic contaminants in the organic stream 212. Both, the organic stream 212 and the aqueous stream 211 can be recycled back to the reactor feed mixer M2. The mixer M2 can include an intermediate feed collection tank or a pipeline flow mixing device during the continuous operation.

[0038] The second column 250 bottom stream 208 can be fed at about mid-section of a third column 270. The second column bottom stream 208 is enriched in the desired reaction product along with some high boiling fraction and some reaction intermediates (e.g. 3- pentenoic acid). In the third column 270, the stream 208 is separated into a reaction intermediates stream 215, while the lactone product is concentrated at the column bottom as the crude product stream 214. The third column 270 can be operated under relatively low pressure (e.g., within a range of about 0.05 atm to about 1 atm) and within a temperature range of about 120 °C to 220 °C.

[0039] The third column 270 overhead stream 215 can be enriched in certain intermediate components, for example, 3 -pentenoic acid, that may be further isomerized to the desired lactone product. In this example, about 80 to 90% of the separated intermediate stream 215 can undergo further chemical transformation in the isomerization reactor 290. A fresh supply of water stream 218 can be provided to the reactor 290, such as to promote isomerization. The water-to-3 -pentenoic acid molar ratio of between about 0.1 to 1 and 10 to 1 can be adequate to promote the secondary reaction in 290. The reactor 290 can be operated at temperatures of up to about 290°C. In an example, the reactor can be a packed bed reactor operated with a residence time ranging from about 30 seconds to about 100 minutes. The secondary reaction product stream 219 from the reactor 290 may either be refined separately or fed to the second column 250 at or near the column bottom.

[0040] The crude product stream 214 exiting the third column 270 can be fed at or near the mid-section of a fourth column 280 for additional product purification. The fourth column 280 can provide additional separation stages such as to purify the desired product in the overhead stream 216. The fourth column bottom stream 217 can include primarily the high- boiling components that can be routed for proper disposal. The fourth column 280 may beDocket No. INV-24031-WO-PCT operated at a relatively low pressure (about 0.05 atm to about 1 atm) and within the temperature range of about 120 to about 280 °C.

[0041] In various aspects, the reaction solution includes a heterogeneous catalyst. The heterogeneous catalyst can be a solid acid catalyst. The solid acid catalyst is a solid in the reaction solution. The solid acid catalyst can be any suitable solid acid catalyst, such as a zeolite (e.g., ZSM-5), an ion-exchange resin (e.g., Amberlyst), tungstated zirconia, a silicoaluminophosphate (e.g., SAPO 34), a perfluorosulfonic acid polymer (e.g., Nafion resin), a solid acid, solid phosphoric acid, sulfonated zirconia, montmorillonite, a sulfated metal oxide, a heteropolyacid, a solid superacid, a mesoporous material, or a combination thereof. The solid acid catalyst can include an ion-exchange resin, a zeolite, tungstated zirconia, or a combination thereof. Zeolites can include crystalline aluminosilicates that can have a three-dimensional network of channels and cavities that act as catalysts due to their acidic nature. Sulfated metal oxide catalysts can include sulfated zirconia (ZrCh), sulfated alumina (AI2O3), and sulfated tin oxide (SnCh) and can exhibit strong acidity.Heteropolyacids can include solid acids based on polyoxometalates, which are metal-oxygen clusters. Examples of heteropolyacids include phosphotungstic acid (H3PW12O40) and phosphomolybdic acid (H3PM012O40). Solid superacids are solid materials of exceptionally high acidity surpassing that of typical liquid acids, with examples including fluorosulfonic acid (FSO3H) and trifluoromethanesulfonic acid (CF3SO3H). Mesoporous materials, such as mesoporous aluminosilicates, can exhibit acidic properties and can act as solid acid catalysts. The solid acid catalyst can form any suitable proportion of the reaction solution, such as 0.001 wt% to 90 wt% of the reaction solution, or 30 wt% to 80 wt%, or less than or equal to 90 wt% and greater than or equal to 0.001 wt% and less than, equal to, or greater than 0.005 wt%, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 89 wt%. The solid acid catalyst can be 0.001 wt% to 95 wt% of a total amount of the solid acid catalyst and the substituted or unsubstituted cyano(C4-Cio)alkene or the hydrolysis product thereof in the reaction solution, or 60 wt% to 90 wt%, or less than or equal to 95 wt% and greater than or equal to 0.001 wt% and less than, equal to, or greater than 0.005 wt%, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, or 94 wt%.

[0042] In various aspects, the reaction solution can be free of added solvents. In other aspects, the reaction solution includes one or more added solvents. The solvent can be any suitable solvent, such as water, an organic solvent, an alcohol, a non-halogenated solvent, a polar solvent, an oxygenated solvent, or a combination thereof. The solvent can beDocket No. INV-24031-WO-PCT commercially and readily available. The solvent can have a normal boiling point not more than 200 °C, 190 °C, 180 °C, or not more than 175 °C, such as for ease of separation, recovery, purification from the reaction effluent, recycle for re-use in the method, or a combination thereof. The solvent can be water. The solvent can form any suitable proportion of the reaction solution, such as 0.001 wt% to 90 wt% of the reaction solution, or 30 wt% to 60 wt%, or less than or equal to 90 wt% and greater than or equal to 0.001 wt% and less than, equal to, or greater than 0.005 wt%, 0.01, 0.05, 0.1, 0.5, 1, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, or 89 wt%.

[0043] The formation of the reaction solution can be performed at any suitable temperature, such as a temperature of -20 °C to 400 °C, or -10 °C to 30 °C, or less than or equal to 400 °C and greater than or equal to -20 °C and less than, equal to, or greater than -15 °C, -10, -9, -8, - 7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 150, 200, 250, 300, or 350 °C. The method can include forming the reaction solution at about room temperature (e.g., 20 °C to 30 °C). In various aspects, the method includes forming the reaction solution and maintaining the reaction solution during the formation thereof at a temperature of about 0 °C, or in a range of -10 °C to about 10 °C, or less than or equal to 10 °C and greater than or equal to -10 °C and less than, equal to, or greater than -9 °C, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, or 9 °C. The forming of the reaction solution can include cooling the reaction solution to maintain or decrease a temperature thereof.

[0044] Allowing the reaction solution to react can include heating the reaction solution to a reaction temperature for a heating duration. For example, the heating can include heating to a reaction temperature of 20 °C to 400 °C, 20 °C to 150 °C, or 40 °C to 90 °C, or less than or equal to 400 °C and greater than or equal to 20 °C and less than, equal to, or greater than 25 °C, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, 250, 300, or 350 °C. The reaction temperature can be maintained for a heating duration of 10 minutes to 24 h, or 30 minutes to 5 h, or less than or equal to 24 h and greater than or equal to 30 minutes and less than, equal to, or greater than 1 h, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or 22 h. The reaction of the reaction solution can be performed at about ambient pressure.

[0045] An advantage of the present disclosure is formation of GVL in high yields, such as a yield of 50% to 100%, or 95% to 100%, or less than or equal to 100% and greater than or equal to 50% and less than, equal to, or greater than 55%, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 98.5, 99, 99.5, 99.9, or 99.99%. The method can include a percentDocket No. INV-24031-WO-PCT conversion of the 3PN of 80% to 100%, or 95% to 100%, or less than or equal to 100% and greater than or equal to 80% and less than, equal to, or greater than 82%, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 98.5, 99, 99.5, 99.9, or 99.99%.

[0046] The GVL formed by the method can be substantially free of byproduct, such as ammonia. For example, byproducts can be 0 wt% to 10 wt% of the produced substituted or unsubstituted gamma-lactone, or 0 wt% to 2 wt%, or less than or equal to 10 wt% and greater than or equal to 0 wt% and less than, equal to, or greater than 0.001 wt%, 0.005, 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 3, 4, 5, 6, 7, 8, or 9 wt%.

[0047] The method can include heating the reaction solution including the heterogeneous catalyst to a reaction temperature of 20 °C to 400 °C, 20 °C to 150 °C, or 40 °C to 90 °C, or less than or equal to 400 °C and greater than or equal to 20 °C and less than, equal to, or greater than 25 °C, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, 250, 300, or 350 °C for a heating duration of 10 minutes to 24 h, or 30 minutes to 5 h, or less than or equal to 24 h and greater than or equal to 30 minutes and less than, equal to, or greater than 1 h, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or 22 h. The method can include forming the GVL from the 3PN and the heterogeneous catalyst at a yield of 80% to 100%, or 95% to 100%, or less than or equal to 100% and greater than or equal to 80% and less than, equal to, or greater than 82%, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 98.5, 99, 99.5, 99.9, or 99.99%. The method can include forming the GVL from the 3PN and the heterogeneous catalyst at a percent conversion of the substituted or unsubstituted 3PN of 80% to 100%, or 95% to 100%, or less than or equal to 100% and greater than or equal to 80% and less than, equal to, or greater than 82%, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 98.5, 99, 99.5, 99.9, or 99.99%. The formed GVL can be substantially free of byproducts; for example, byproducts can be 0 wt% to 10 wt% of the produced GVL, or 0 wt% to 2 wt%, or less than or equal to 10 wt% and greater than or equal to 0 wt% and less than, equal to, or greater than 0.001 wt%, 0.005, 0.01, 0.05, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.2, 1.4, 1.6, 1.8, 2, 3, 4, 5, 6, 7, 8, or 9 wt%.

[0048] The method can include allowing the reaction solution to react to form the GVL in any suitable type of reactor. For example, the reactor can be a batch reactor. In various aspects, the reactor is a continuous reactor.

[0049] In various aspects, the method can be of great industrial importance. The method can make use of the 3PN-containing organic feedstock that is commercially produced in high yields and purity from a large-scale 1,3 -butadiene hydrocyanation process. The butadiene double hydrocyanation to dinitrile is a critical chemical route toward making one of theDocket No. INV-24031-WO-PCT required nylon monomers, specifically Ce diamine or HMD. The hydrocyanation process is a matured and well-optimized process in the world of nylon intermediates manufacture. Therefore, the scale and availability of the unsaturated nitrile favors the viability and industrial utility of the disclosed process. The unsaturated nitrile feedstock, such as 2PN, 3PN, 2-methyl-3 -butenenitrile, or di cyanobutene, will always be available in abundance.

[0050] In various aspects, the mixed feed stream is advantageously free of chemical components such as furfural, levulinic acid, or its alkyl esters (e.g., methyl, ethyl, or isopropyl esters of levulinic acid), furfuryl alcohol, 4-hydroxyvaleric acid, or a combination thereof, which can have a concentration in the reaction solution of 0 wt%, 0 wt% to 0.1 wt%, 0 wt% to 0.001 wt%, < 1 wt.%, < 0.5 wt.%, < 0.1 wt.%, < 100 ppmw, or < 50 ppmw.

[0051] In various aspects, the method of the present disclosure produces substantially low or no impurities or undesired side products. In various aspects, one or more streams of the present disclosure can have a low or zero concentration of certain chemical components, such as, alpha-angelica lactone, furfural -propyl ether, 2-methyl-tetrahydrofuran, 2-butanol, 2- pentanol, 1,4-pentanediol, heavy acid, furfuryl alcohol resin, furfural, 4-cyclopentene-l,3- dione, propylmalonic acid, pentyl-cyclopropane, 2-cyclopenten-l-one, 5-methyl-2(3H)- Furanone, 2-hexyl cyclopentanone, tetrahydro furfuryl alcohol, trans-2-undecen-l-ol, pentanoic acid, levulinic acid or its alkyl (e.g.: methyl, ethyl or iso-propyl) esters, furfuryl alcohol or 4-hydroxyvaleric acid. In various embodiments, these chemical components can be present in the reacted reaction solution at concentrations selected from 0 wt%, 0 wt% to 0.1 wt%, 0 wt% to 0.001 wt%, < 1 wt.%, < 0.5 wt.%, < 0.1 wt.%, < 100 ppmw, and < 50 ppmw. In some embodiments, the concentration of one or more of the chemical components listed in this paragraph can be undetectable using currently available analytical techniques.

[0052] Further, the cost-effective hydrolysis and lactonization of 3PN to the gamma-lactone GVL provides utilization of the unsaturated nitrile 3PN in non-nylon applications. The GVL of the present method can be useful as a bio-degradable solvent in semiconductor / electronic parts cleaning, paints & dyes, petrochemical extractions, and the like. Conventionally employed solvents in these industries, such as N-methyl-2-pyrrolidone (NMP), N,N’- dimethylpropyleneurea (DMPU), dimethylacetamide (DMAc), dimethylformamide (DMF), dimethylsulfoxide (DMSO), and acetone, are environmentally unfriendly solvents. The gamma-lactone of the present method can be a viable substitute as a drop-in-replacement for these solvents.Docket No. INV-24031-WO-PCTEXAMPLES

[0053] Various aspects of the present disclosure can be better understood by reference to the following Examples which are offered by way of illustration. The present disclosure is not limited to the Examples given herein.

[0054] Materials used in the Examples. The 3-PN feed was obtained from an industrial nitrile manufacturing facility. The 3-PN feed composition was 99 wt% 3PN and 1 wt% 2PN. An example of 3-PN feed may be an intermediate product stream obtained from adiponitrile manufacture process.Example 1.

[0055] The method, represented in FIG. 1, is employed in this Example. Tables 1-2 provide a stream summary corresponding to the FIG. 1 method. The major streams are represented in FIG. 1 and auxiliary certain equipment such as pumps, purge points, instruments, fittings, etc. are not shown in FIG. 1.Docket No. INV-24031-WO-PCT

[0056] TABLE 1.Docket No. INV-24031-WO-PCT

[0057] TABLE 2.

[0058] About 100 kg / hr water-3PN feed stream 101 is mixed with two recycle streams 111 and 112. The total mixed feed stream 102 includes about 60:40 (wt:wt) of 3PN:water. The mixed feed stream 102 is preheated to about 116 C and the vapor-liquid feed mixture 103 is fed to the reactor 120. The conditions in the reactor 120 are maintained such that the 3PN undergoes hydrolysis with water followed by lactonization (or ring closure) to form the desired product gamma-valerolactone (GVL). The hydrolysis reaction evolves ammonia originating from the nitrile group in the 3PN.Docket No. INV-24031-WO-PCT

[0059] The reactor effluent stream 104 is cooled from about 290 C to about 120 C in the effluent cooler 130. The cooled partially condensed effluent stream 105 is fed to the first column 140. The operating conditions in the first column 140 are maintained such that an overhead gaseous ammonia-rich stream 107 is obtained from the first column 140. The first column bottom stream 106 is devoid of any ammonia species and exits the column.

[0060] The ammonia-lean stream 106 is fed to the second column 150, wherein, the desired lactone product and the near-boiling intermediates are further concentrated in the bottom stream 108 while recovering the excess water and 3PN in the second column overhead stream 109. An adequate residence time is allowed in the phase separator 160 and the conditions are maintained such that for the overhead stream 109 phase separates into a water-rich stream 111 and an organic-rich stream 112. The concentration of impurities in these two streams is maintained by taking a small purge of each out of the process. The two streams contain useful reactants, mainly 3PN and water, and are recycled to the process and upstream of the reactor 120. Stream 111 contains the excess water and stream 112 contains the unreacted 3PN, both of which are useful in reactor 120.

[0061] The second column 150 bottom stream 108 undergoes further refinement in the third column 170, wherein the crude product stream 114 is obtained from the column. The reaction intermediates, including 3 -pentenoic acid, concentrate in the overhead stream 115. This intermediates stream 115 may be further processed for purification or disposed.

[0062] The fourth column 180 is operated to purify the desired product as the overhead stream 116. The high-boiling components and impurities accumulate at the fourth column 180 bottom and can be discharged as the bottom stream 117.

[0063] The disclosed method is effective in producing a high-purity gamma-valerolactone starting from the 3PN feed. The refined product stream 116 of at least 99.99% purity is suitable for many industrial applications.

[0064] The recycling of the excess water and unreacted 3PN provides a lower carbon footprint via reduced organic waste and water conservation.Example 2,

[0065] An exemplary method, represented in FIG. 2, is employed in this Example. Tables 3- 5 provide a stream summary corresponding to the FIG. 2 process. The major streams are represented in FIG. 2 and certain auxiliary equipment such as pumps, purge points, instruments, fittings, etc. are not necessarily shown in FIG. 2.Docket No. INV-24031-WO-PCT

[0066] TABLE 3.Docket No. INV-24031-WO-PCT

[0067] TABLE 4.Docket No. INV-24031-WO-PCT

[0068] TABLE 5.

[0069] Example 2 can be performed similar to the steps recited in Example 1, with exception the third column 270 overhead stream 215, containing the reaction intermediates including 3- pentenoic acid, is further reacted with additional water stream 218 in the second reactor 290 to produce additional lactone product. The water-to-3 -pentenoic acid stream molar ratio of about 0.8-0.9 is used in this Example. The 3-pentenoic acid is completely converted to its lactone product in the second reactor 290. The reaction effluent stream 219 from second reactor 290 is fed to the second column 250 and joins rest of the purification step.

[0070] The Example 1 method produces about 54.4 kg / hr purified lactone product starting from about 58.9 kg / hr 3-PN present in the feed stream 101. The Example 2 method produces about 67.8 kg / hr purified lactone product starting from about 59 kg / hr 3-PN present in the feed stream 201. The additional lactone product improves the overall process yield in Example 2.Definitions.

[0071] Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example,Docket No. INV-24031-WO-PCT a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.

[0072] In this document, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” or “at least one of A or B” has the same meaning as “A, B, or A and B .” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.

[0073] In the methods described herein, the acts can be carried out in a specific order as recited herein. Alternatively, in any aspect(s) disclosed herein, specific acts may be carried out in any order without departing from the principles of the present disclosure, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately or the plain meaning of the claims would require it. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0074] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range and includes the exact stated value or range.

[0075] The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. The term “substantially free of’ as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that about 0 wt% to about 5 wt% of the composition is the material, or about 0 wt% to about 1 wt%, or about 5 wt% or less, or less than, equal to, or greater than about 4.5 wt%, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 wt% or less, or about 0 wt%.Docket No. INV-24031-WO-PCT

[0076] The above Detailed Description can include references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as “examples.” Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[0077] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that can include elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim.

[0078] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” can include “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. In this document, the terms “including” and “in which” are used as the plain-English equivalents of the respective terms “comprising” and “wherein.” Also, in the following claims, the terms “including” and “comprising” are open-ended, that is, a system, device, article, composition, formulation, or process that can include elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms “first,” “second,” and “third,” etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[0079] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) can be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It isDocket No. INV-24031-WO-PCT submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features can be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter can lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various combinations or permutations. The scope of the present disclosure should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.Exemplary Aspects.

[0080] The following, non-limiting aspects of the present disclosure solve the challenges and provide the benefits discussed herein, among others. The numbering of the aspects is not to be construed as designating levels of importance.

[0081] Aspect l is a method of forming gamma valerolactone (GVL), the method comprising: contacting, within a first reactor, a mixed feed stream comprising a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of seven atmosphere or less, whereby GVL is formed; separating, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water; and routing the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor whereby further GVL is formed.

[0082] Aspect 2 provides the subject matter of Aspect 1, wherein the heterogenous catalyst includes at least one of a solid acid catalyst, a metallic catalyst, or a combination thereof.

[0083] Aspect 3 provides the subject matter of any one of Aspects 1-2, wherein the first temperature is within a range of one hundred degrees Celsius (°C) to four hundred °C.

[0084] Aspect 4 provides the subject matter of any one of Aspects 1-3, wherein the first pressure is a pressure within a range of one atmosphere and seven atmospheres.

[0085] Aspect 5 provides the subject matter of any one of Aspects 1^1, wherein the mixed feed stream includes a molar ratio of water to 3PN within a range of one-to-one to twenty -to- one.Docket No. INV-24031-WO-PCT

[0086] Aspect 6 provides the subject matter of any one of Aspects 1-5, wherein routing the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor includes combining the second stream of any unreacted 3PN and the second stream of unreacted water with the mixed feed stream.

[0087] Aspect 7 provides the subject matter of any one of Aspects 1-6 including at least partially vaporizing the mixed feed stream or the second stream of any unreacted 3PN.

[0088] Aspect 8 provides the subject matter of any one of Aspects 1-7, wherein separating from the GVL a second stream of any unreacted 3PN and a second stream of unreacted water includes routing an effluent stream from the first reactor to a first column, including a condenser and a reboiling unit, to produce a first overhead stream comprising concentrated ammonia, and a first bottom stream; routing the first bottom stream from the first column to a second column to produce a second overhead stream and a second bottom stream, the second column including a phase separator to separate the second overhead stream into a plurality of phases, the plurality of phases including an organic stream and an aqueous stream; wherein the organic stream and the aqueous stream are routed to the first reactor whereby further GVL is formed.

[0089] Aspect 9 provides the subject matter of Aspect 8, wherein separating from the GVL a second stream of any unreacted 3PN and a second stream of unreacted water includes routing to a third column the second bottom stream from the second column to concentrate a lactone product as a crude product stream.

[0090] Aspect 10 provides the subject matter of any one of Aspects 1-9, wherein the method is continuous.

[0091] Aspect 11 provides the subject matter of any one of Aspects 1-10 including purifying the totality of GVL that is formed to a purity greater than eighty-five weight percentage (wt%).

[0092] Aspect 12 provides a system for forming gamma valerolactone (GVL), the system comprising: a first reactor configured to contact a mixed feed stream comprising a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of seven atmosphere or less, whereby GVL is formed; one or more columns configured to separate, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water; and a recycling circuit configured to route the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor whereby further GVL is formed.Docket No. INV-24031-WO-PCT

[0093] Aspect 13 provides the subject matter of Aspect 12, wherein the heterogenous catalyst includes at least one of a solid acid catalyst, a metallic catalyst, an acid, or a combination thereof.

[0094] Aspect 14 provides the subject matter of any one of Aspects 12-13, wherein the first temperature is within a range of one hundred degrees Celsius (°C) to four hundred °C.

[0095] Aspect 15 provides the subject matter of any one of Aspects 12-14, wherein the first pressure is a pressure within a range of one atmosphere and seven atmospheres.

[0096] Aspect 16 provides the subject matter of any one of Aspects 12-15, wherein the mixed feed stream includes a molar ratio of water to 3PN within a range of one-to-one to twenty -to-one.

[0097] Aspect 17 provides the subject matter of any one of Aspects 12-16, including a vaporizer configured to at least partially vaporize the mixed feed stream or the second stream of any unreacted 3PN.

[0098] Aspect 18 provides the subject matter of any one of Aspects 12-17, wherein the one or more columns configured to separate, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water include: a first column, including a condenser and a reboiling unit, arranged to receive an effluent stream from the first reactor to produce a first overhead stream comprising concentrated ammonia, and a first bottom stream; a second column configured to receive the first bottom stream from the first column to produce a second overhead stream and a second bottom stream, the second column including a phase separator to separate the second overhead stream into a plurality of phases, the plurality of phases including an organic stream and an aqueous stream; wherein the organic stream and the aqueous stream are routed via the recycling circuit to the first reactor whereby further GVL is formed.

[0099] Aspect 19 provides the subject matter of any one of Aspects 12-18, wherein the system is configured for continuous processing of the mixed feed stream.

[0100] Aspect 20 provides at least one machine-readable medium including instructions that, when executed by processing circuitry, cause the processing circuitry to perform operations to implement of any one of Aspects 1-19.

[0101] Aspect 21 provides an apparatus comprising means to implement the method of any one of Aspects 1-11.

[0102] Aspect 22 provides a system to implement the method of any one of Aspects 1-11.

[0103] Aspect 23 provides a method to implement the system of any one of Aspects 12-19.

Claims

Docket No. INV-24031-WO-PCTCLAIMSWhat is claimed is:

1. A method of forming gamma valerolactone (GVL), the method comprising: contacting, within a reactor, a mixed feed stream comprising a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of 7 atmosphere or less, whereby GVL is formed; separating, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water; and routing the second stream of any unreacted 3PN and the second stream of unreacted water to the reactor whereby further GVL is formed.

2. The method of claim 1, wherein the heterogenous catalyst comprises at least one of a solid acid catalyst, an acid catalyst, and a metallic catalyst.

3. The method of claim 1, wherein the first temperature is within a range of 100 degrees Celsius (°C) to 400°C.

4. The method of claim 1, wherein the first pressure is within a range of 1 atm and 7 atm.

5. The method of claim 1, wherein the mixed feed stream comprises a molar ratio of water to 3PN within a range of 1 : 1 to 20: 1.

6. The method of claim 1, wherein routing the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor comprises combining the second stream of any unreacted 3PN and the second stream of unreacted water with the mixed feed stream.

7. The method of claim 1, comprising at least partially vaporizing the mixed feed stream or the second stream of any unreacted 3PN.Docket No. INV-24031-WO-PCT8. The method of claim 1, wherein separating from the GVL the second stream of any unreacted 3PN and the second stream of unreacted water comprises: routing an effluent stream from the first reactor to a first column comprising a condenser and a reboiling unit to produce a first overhead stream comprising concentrated ammonia and a first bottom stream; routing the first bottom stream from the first column to a second column to produce a second overhead stream and a second bottom stream, the second column comprising a phase separator to separate the second overhead stream into a plurality of phases, the plurality of phases comprising an organic stream and an aqueous stream; and routing the organic stream and the aqueous stream to the first reactor whereby the further GVL is formed.

9. The method of claim 8, wherein separating from the GVL the second stream of any unreacted 3PN and the second stream of unreacted water comprises routing to a third column the second bottom stream from the second column to concentrate a lactone product as a crude product stream.

10. The method of claim 1, wherein the method is continuous.

11. The method of claim 1, comprising purifying the totality of GVL that is formed to a purity greater than 85 weight percentage (wt%).

12. The method of claim 1, further comprising recovering a stream enriched in 3- pentenoic acid and isomerizing the recovered stream to provide a stream enriched in at least one lactone.

13. A system for forming gamma valerolactone (GVL), the system comprising: a first reactor configured to contact a mixed feed stream comprising a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of 7 atmosphere or less such that GVL is formed; one or more columns configured to separate, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water; andDocket No. INV-24031-WO-PCT a recycling circuit configured to route the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor such that further GVL is formed.

14. The system of claim 13, wherein the heterogenous catalyst comprises at least one of a solid acid catalyst, a metallic catalyst, and an acid.

15. The system of claim 13, wherein the first temperature is within a range of 100 degrees Celsius (°C) to 400°C, and wherein the first pressure is a pressure within a range of 15 psi and 100 psi.

16. The system of claim 13, wherein the mixed feed stream comprises a molar ratio of water to 3PN within a range of 1 : 1 to 20: 1.

17. The system of claim 13, comprising a vaporizer configured to at least partially vaporize the mixed feed stream or the second stream of any unreacted 3PN.

18. The system of claim 13, wherein the one or more columns configured to separate, from the GVL, the second stream of any unreacted 3PN and the second stream of unreacted water comprise: a first column, comprising a condenser and a reboiling unit, arranged to receive an effluent stream from the first reactor to produce a first overhead stream comprising concentrated ammonia, and a first bottom stream; and a second column configured to receive the first bottom stream from the first column and to produce a second overhead stream and a second bottom stream, the second column comprising a phase separator to separate the second overhead stream into a plurality of phases, the plurality of phases comprising an organic stream and an aqueous stream; wherein the recycling circuit is configured to route the organic stream and the aqueous stream to the first reactor such that further GVL is formed.

19. A system for forming gamma valerolactone (GVL), the system comprising: a reactor for contacting, within a first reactor, a mixed feed stream comprising a first stream of unreacted 3 -pentenenitrile (3PN) and a first stream of unreacted water in the presence of a heterogeneous catalyst at a first temperature and under a first pressure of 7 atmosphere or less, such that GVL is formed;Docket No. INV-24031-WO-PCT a separator for separating, from the GVL, a second stream of any unreacted 3PN and a second stream of unreacted water; and a conduit for routing the second stream of any unreacted 3PN and the second stream of unreacted water to the first reactor such that further GVL is formed.

20. The system of claim 19 further comprising a separator for recovering a stream enriched in 3 -pentenoic acid and a reactor for receiving the recovered enriched stream and isomerizing the recovered stream to provide a stream enriched in at least one lactone.

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