Method for synthesizing paraxylene and catalyst thereof

Abstract

Processes and catalysts for the cycloaddition of olefins, such as C2 to C4 olefins, such as ethylene, propylene and butene, to biomass-derived compounds, such as dimethylfuran, furan, methylfuran. The catalyst has a relatively low silica to alumina ratio of about 25 compared to conventional catalysts having a silica to alumina ratio of greater than 1000. The catalyst has phosphorus and may be a beta zeolite. Such catalysts can be used to produce high yields of bio-based paraxylene.

Description

[0001] Priority Claim

[0002] This application claims priority to U.S. Patent Application Serial No. 63 / 477,097, filed December 23, 2022, the entire content of which is incorporated herein by reference. Field of the Invention

[0003] The present invention generally relates to the production of aromatic hydrocarbons from biomass-derived compounds, and more particularly to an overall biobased route for preparing p-xylene from carbohydrates such as hexoses (e.g., glucose or fructose). Background of the Invention

[0004] C8 alkyl aromatic hydrocarbons are generally considered valuable products, with the highest demand for p-xylene. For example, p-xylene is used in the commercial synthesis of terephthalic acid, which is a raw material in the manufacture of polyester fabrics.

[0005] The main sources of p-xylene include mixed xylene streams obtained from crude oil refining. Examples of such streams are those produced by commercial xylene isomerization processes or by separating C8 alkyl aromatic hydrocarbon fractions derived from catalytic reformate products by liquid-liquid extraction and fractional distillation. p-Xylene can be separated from a p-xylene-containing feed stream that typically contains a mixture of all three xylene isomers by crystallization and / or adsorption separation.

[0006] Accordingly, most p-xylene is produced from petroleum-based feedstocks. However, producing p-xylene from petroleum-based feedstocks remains dependent on refined petroleum and generates greenhouse gas emissions. A biobased p-xylene alternative from renewable feedstocks would reduce greenhouse gas (GHG) emissions and decrease dependence on petroleum resources. Without being bound by any theory, it is believed that biobased p-xylene can be carbon negative.

[0007] Recently, it has been proposed that p-xylene can be prepared from biomass-derived components. For example, producing p-xylene from sustainable sugar-derived furans such as dimethylfuran (DMF) provides an alternative route to traditional petroleum-based production.

[0008] Accordingly, there has been a continuing need and desire to improve methods for producing p-xylene from biomass-derived compounds. Summary of the Invention

[0009] The present invention describes the cycloaddition of olefins (such as C2 to C4 olefins, like ethylene, propylene, and butene) to biomass-derived compounds (such as dimethylfuran, furan, methylfuran). Compared with conventional catalysts having a silica to alumina ratio greater than 1000, the catalyst has a relatively low silica to alumina ratio of about 25. The catalyst has phosphorus and can be a 12-ring zeolite, such as beta zeolite. Such catalysts can be used to produce high yields of bio-based pX.

[0010] Advantageously, the DMF starting material for the process can be synthesized from carbohydrates, thus providing a production route for p-xylene that is at least partially dependent on renewable feedstocks and consists of components derived from biomass.

[0011] Thus, in at least one aspect, the invention can be characterized by providing a method for cycloaddition of an olefin to a biomass-derived compound by contacting the olefin and the biomass-derived compound with a catalyst. The catalyst contains silicon and aluminum in a ratio less than 1:1000 and further contains phosphorus.

[0012] The catalyst can be beta zeolite.

[0013] The ratio of silicon to aluminum can be between 1:1 and 1:500, or between 1:1 and 1:25.

[0014] The catalyst can contain 0.001 wt% to 10 wt% of phosphorus.

[0015] Broadly, the invention can also be characterized by providing a method for producing p-xylene by the steps of: providing an olefin; providing a compound derived from biomass; and contacting the olefin and the compound derived from biomass in the presence of a catalyst. The catalyst contains silicon and aluminum in a ratio less than 1:1000 and further contains phosphorus.

[0016] The molar ratio of the olefin to the compound derived from biomass can be in the range of 1:100 to 100:1.

[0017] The weight ratio of the catalyst to the compound derived from biomass can be in the range of 0.001:1 to 10:1.

[0018] The contacting can occur at a temperature in the range of 100 °C to 500 °C.

[0019] The contacting can occur at a pressure in the range of 689 kPa to 17,237 kPa (100 psig to 2,500 psig).

[0020] The method can be a continuous method or a batch method.

[0021] The catalyst can be beta zeolite.

[0022] The ratio of silicon to aluminum of the catalyst can be between 1:1 and 1:500, or between 1:1 and 1:25.

[0023] The catalyst can contain 0.001 wt% to 10 wt% of phosphorus.

[0024] In at least one aspect, the present invention can generally further be characterized by providing a catalyst for converting biomass-derived compounds into aromatics with olefins. The catalyst comprises a porous support formed of silicon and aluminum with a ratio less than 1:100 and phosphorus.

[0025] The catalyst can be beta zeolite.

[0026] The ratio of silicon to aluminum can be between 1:1 and 1:25.

[0027] The catalyst can contain 0.001 wt% to 10 wt% of phosphorus.

[0028] Additional aspects, embodiments, and details of the present invention (all of which can be combined in any way) are set forth in the following detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be described below in conjunction with the following drawings, wherein:

[0030] Figure 1 is a graph showing the p-xylene yield of a conventional catalyst and a new catalyst according to one or more aspects of the present invention compared with the amount of phosphorus;

[0031] Figure 2 is a graph showing the p-xylene selectivity of a conventional catalyst and a new catalyst according to one or more aspects of the present invention compared with the DMF conversion rate; and,

[0032] Figure 3 is a graph showing the p-xylene selectivity of a conventional catalyst and a new catalyst according to one or more aspects of the present invention compared with the DMF conversion rate. DETAILED DESCRIPTION

[0033] As described above, the present invention relates to the production of aromatic hydrocarbons from biomass-derived components, and particularly p-xylene. In the present invention, a new catalytic material is provided.

[0034] Taking these general principles into account, one or more embodiments of the present invention will be described on the understanding that the following description is not intended to be limiting.

[0035] As used herein, "biomass" includes, but is not limited to, lignin, plant parts, fruits, vegetables, plant processing waste, wood chips, rice husks, grains, grasses, corn, corn husks, waste, aquatic plants, hay, paper stock, paper products, recycled paper and paper products, and any cellulose, lignin, or combinations thereof containing biological or bio-derived materials.

[0036] In a known manner, biomass can be used to produce aromatic compounds such as furans, methylfurans, dimethylfurans, and in particular 2,5-dimethylfuran (DMF). See, for example, U.S. Pat. Nos. 7,572,925 and 8,772,515.

[0037] The biomass-derived component reacts with an olefin (particularly a C2 to C4 olefin) in the presence of a catalyst. According to the present invention, it comprises a porous support containing silica and alumina and having a ratio of silicon to aluminum of less than 1:1000, particularly 1:1 to 1:500, or 1:100, or 1:25. The support can be a zeolite, such as a 12-ring zeolite, and in particular beta zeolite.

[0038] The catalyst also contains phosphorus. Specifically, the catalyst contains phosphorus in the range of 0.001 wt% to 10 wt%, or even in the range of 0.01 wt% to 10 wt%. The addition of phosphorus reduces the number of weak acid sites of the catalyst. However, such catalysts provide a suitable catalyst with a high and effective production yield.

[0039] NH₃-TPD analysis was carried out on a conventional non-phosphorylated catalyst and catalysts with different amounts of phosphorus according to the present disclosure. The results of the NH₃-TPD are shown in Table 1 below.

[0040] Table 1

[0041]

[0042] As demonstrated by the data in Table 1, the addition of phosphorus reduces the number of acid sites.

[0043] The reaction of the biomass-derived compound with the olefin is carried out under suitable cycloaddition reaction conditions in the presence of the catalyst as discussed above. The molar ratio of the olefin to the biomass-derived compound can be in the range of 1:100 to 100:1, or 1:50 to 50:1, or 1:10 to 10:1, or 1:1 to 2:1. The weight ratio of the catalyst to the biomass-derived compound can be in the range of 0.001:1 to 10:1, or between 0.01:1 and 10:1.

[0044] One or more reactants can be in another liquid (such as hydrocarbon oil).

[0045] Exemplary temperatures in a reactor or reaction zone where a catalyst is disposed (e.g., in a batch reactor or as a fixed bed or moving bed in a continuous reaction system) are in the range of 100 °C to 500 °C, or between 200 °C (392 °F) and 300 °C (572 °F), and are typically 150 °C (302 °F) to 225 °C (437 °F). Advantageous cycloalkylation reaction conditions also include a reaction pressure between 689 kPa and 17,237 kPa (100 psig and 2,500 psig) or between 1,379 kPa and 13,790 kPa (200 psig and 2,000 psig).

[0046] Whether the reaction is carried out batchwise or continuously, the cycloaddition reaction conditions generally also include a reactor residence time in the range of 0.1 seconds to 48 hours, or in the range of 3 hours to 30 hours, or in the range of 6 to 10 hours. The reactor residence time can depend on a variety of factors, including in the case of a continuous process where unreacted / reactants are recycled to provide a relatively high overall conversion, even though the single-pass conversion is significantly lower. The biomass-derived compound can be fed continuously, for example, at a liquid hourly space velocity (LHSV) of 0.05 h -1 to 5 h -1 to the cycloaddition reaction zone. As understood in the art, the liquid hourly space velocity (LHSV, expressed in h -1 units) is the volumetric flow rate of the liquid over the catalyst bed divided by the bed volume and represents the number of equivalent volumes of the catalyst bed of liquid processed per hour. Thus, the LHSV is closely related to the reciprocal of the reactor residence time.

[0047] In an exemplary continuous process, the reactants are fed continuously into one or more reactors containing a catalyst, which can be a CSTR-type reactor (stirred tank) or the reactor comprises a fixed bed of catalyst (e.g., in a swing bed reactor system having a plurality of fixed bed reactors), and the product containing the converted p-xylene is continuously withdrawn together with the unreacted reactants and reaction by-products (such as 2,5-hexanedione). Preferably, one or more separation operations (e.g., flash separation or distillation), using single-stage or multi-stage vapor-liquid equilibrium contacting, are used to separate the unreacted materials, for example, based on the difference in the relative volatility of the unreacted materials. In some cases, it may be necessary to convert 2,5-hexanedione (which is a by-product of the hydration of DMF) back to DMF to increase the product yield.

[0048] Alternatively, the unreacted components can be recycled back to the feed without drying or without additional drying to remove water. At least for recycling, drying or reducing the water content will reduce the formation of hexanedione and reduce side reactions caused by the presence of water during the dehydration reaction. Drying can be carried out via distillation or molecular sieves.

[0049] Accordingly, aspects of the present invention relate to methods for producing p-xylene, which include the catalytic cycloaddition of ethylene to DMF, and thereby advantageously allow the use of carbohydrates and in particular hexoses (e.g., glucose or fructose) as starting materials. In particular, DMF can be obtained by converting hexoses into HMF and then hydrogenating HMF to DMF. Thus, at least 6 carbon atoms in the carbon atoms of p-xylene (i.e., those derived from hexoses) can be derived from renewable raw materials. In addition, using biomass-derived ethanol as a source for the feed ethylene enables the entire p-xylene molecule to be derived from "green" sources. Thus, a particular method for producing p-xylene as described herein includes converting hexoses such as glucose or fructose into HMF, hydrogenating HMF to DMF, and reacting DMF with ethylene under cycloaddition reaction conditions and in the presence of a catalyst to produce p-xylene. Additional methods according to the present invention include these features and the additional element of oxidizing p-xylene with oxygen to produce terephthalic acid, which is a precursor to a valuable material that has hitherto been commercially produced only from petro-based sources.

[0050] Experiment

[0051] In a batch method, 12 wt% of DMF in octane was reacted with ethylene (ethylene:DMF molar ratio of 1.62) at 285 °C for 6 hours in the presence of phosphorus-containing beta zeolite to produce p-xylene. As shown in the appendix Figure 1 shown, the addition of phosphorus provides a p-xylene yield similar to that of conventionally used catalysts that do not contain phosphorus. As shown in Figure 2 shown, under these conditions, the new catalyst shows an increased selectivity towards p-xylene. Figure 2 The new catalyst in has 1 wt% phosphorus, except for catalysts represented by different symbols (which contain less than 1 wt% phosphorus).

[0052] In another method, DMF was reacted with ethylene (ethylene:DMF molar ratio of 1.0) at 250 °C for 6 hours in the presence of phosphorus-containing beta zeolite to produce p-xylene. As shown in the appendix Figure 3 shown, the new catalyst again shows an increased selectivity towards the production of p-xylene.

[0053] Above, in order to calculate the conversion and selectivity, due to the equilibrium hydration / dehydration reaction of DMF with HDO, HDO is considered to be the unreacted DMF in the product. The following formula is used:

[0054] [Formula 1]

[0055]

[0056] [Formula 2]

[0057]

[0058] [Formula 3]

[0059]

[0060] Specific implementation

[0061] Although the following is described in connection with specific embodiments, it should be understood that the description is intended to illustrate and not limit the scope of the foregoing description and the appended claims.

[0062] A first embodiment of the present invention is a method for cycloaddition of an olefin to a biomass-derived compound, the method comprising contacting the olefin and the biomass-derived compound with a catalyst comprising silicon and aluminum in a ratio less than 1:1000, wherein the catalyst further comprises phosphorus. One embodiment of the present invention is one, any, or all of the embodiments from the first embodiment of this paragraph to the previous embodiments of this paragraph, wherein the catalyst comprises beta zeolite. One embodiment of the present invention is one, any, or all of the embodiments from the first embodiment of this paragraph to the previous embodiments of this paragraph, wherein the ratio of silicon to aluminum is between 1:1 and 1:500. One embodiment of the present invention is one, any, or all of the embodiments from the first embodiment of this paragraph to the previous embodiments of this paragraph, wherein the ratio of silicon to aluminum is between 1:1 and 1:25. One embodiment of the present invention is one, any, or all of the embodiments from the first embodiment of this paragraph to the previous embodiments of this paragraph, wherein the catalyst comprises 0.001 wt% to 10 wt% of phosphorus.

[0063] A second embodiment of the present invention is a method for producing p-xylene, the method comprising: providing an olefin; providing a compound derived from biomass; contacting the olefin with the compound derived from biomass in the presence of a catalyst, the catalyst comprising silicon and aluminum in a ratio less than 1:1000, wherein the catalyst further comprises phosphorus. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the molar ratio of the olefin to the compound derived from biomass is in the range of 1:100 to 100:1. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the weight ratio of the catalyst to the compound derived from biomass is in the range of 0.001:1 to 10:1. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the contacting is carried out at a temperature in the range of 100 °C to 500 °C. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the contacting is carried out at a pressure in the range of 689 kPa to 17,237 kPa (100 psig to 2,500 psig). An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the method is a continuous method. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the method is a batch method. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the catalyst comprises beta zeolite. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the ratio of silicon to aluminum is between 1:1 and 1:500. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the ratio of silicon to aluminum is between 1:1 and 1:25. An embodiment of the present invention is one, any, or all of the embodiments from the second embodiment of this paragraph to the previous embodiments of this paragraph, wherein the catalyst comprises 0.001 wt% to 10 wt% of phosphorus.

[0064] A third embodiment of the present invention is a catalyst for converting biomass-derived compounds into aromatics with olefins, the catalyst comprising a porous support formed of silicon and aluminum in a ratio less than 1:100; and phosphorus. An embodiment of the present invention is one, any, or all of the previous embodiments from the third embodiment of this paragraph to the previous embodiments of this paragraph, wherein the catalyst comprises beta zeolite. An embodiment of the present invention is one, any, or all of the previous embodiments from the third embodiment of this paragraph to the previous embodiments of this paragraph, wherein the ratio of silicon to aluminum is between 1:1 and 1:25. An embodiment of the present invention is one, any, or all of the previous embodiments from the third embodiment of this paragraph to the previous embodiments of this paragraph, wherein the catalyst contains 0.001% to 10% by weight of phosphorus.

[0065] Although no further detailed description is provided, it is believed that those skilled in the art can make the most of the present invention by using the foregoing description and can easily determine the basic features of the present invention without departing from the essence and scope of the present invention to make various changes and modifications thereto and adapt it to various uses and conditions. Therefore, the foregoing preferred specific embodiments should be understood as being merely illustrative and not in any way limiting the remainder of the disclosure, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0066] In the foregoing, all temperatures are shown in degrees Celsius and all parts and percentages are by weight, unless otherwise indicated.

[0067] Although at least one exemplary embodiment has been presented in the foregoing detailed description of the present invention, it should be understood that there are numerous variations. It should also be understood that one exemplary embodiment or multiple exemplary embodiments are merely examples and are not intended to limit the scope, applicability, or construction of the present invention in any way. On the contrary, the foregoing detailed description will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiments of the present invention, and it should be understood that various changes can be made to the functions and arrangements of the elements described in the exemplary embodiments without departing from the scope of the present invention as set forth in the appended claims and their legal equivalents.

Claims

1. A method for cycloaddition of an olefin to a biomass-derived compound, the method comprising: contacting an olefin and a biomass-derived compound with a catalyst, wherein the catalyst comprises silicon and aluminum in a ratio less than 1:1000, and wherein the catalyst further comprises phosphorus.

2. The method according to claim 1, wherein the catalyst comprises beta zeolite.

3. The method according to claim 1, wherein the ratio of silicon to aluminum is between 1:1 and 1:

500.

4. The method according to claim 1, wherein the ratio of silicon to aluminum is between 1:1 and 1:

25.

5. The method according to any one of claims 1 to 4, wherein the catalyst comprises phosphorus in an amount between 0.001 wt% and 10 wt%.

6. The method according to any one of claims 1 to 4, wherein the molar ratio of the olefin to the compound derived from the biomass is in the range of 1:100 to 100:1 or in the range of 0.001:1 to 10:

1.

7. The method according to any one of claims 1 to 4, wherein the contacting is carried out at a temperature in the range of 100 °C to 500 °C.

8. The method according to any one of claims 1 to 4, wherein the contacting is carried out at a pressure in the range of 689 kPa to 17,237 kPa (100 psig to 2,500 psig).

9. The method according to any one of claims 1 to 4, wherein the method is a continuous method.

10. The method according to any one of claims 1 to 4, wherein the method is a batch method.

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