System and Method for Converting Waste Polyolefins, Renewable Oils, and Paraffinic Crudes to Aromatic Compounds

This application claims priority and is a Continuation-In-Part of co-pending U.S. patent application Ser. No. 17/494,360, entitled Chemolytic Upgrading of Low-Value Macromolecule Feedstocks to Higher-Value Fuels and Chemicals, filed on Oct. 5, 2021, which claims the benefit of U.S. Provisional Patent Applications Ser. Nos. 63/089,725, entitled Chemolytic Upgrading of Low-Value Macromolecule Feedstocks to Higher-Value Fuels and Chemicals, filed on Oct. 9, 2020, and 63/092,313, entitled Chemolytic Upgrading of Low-Value Macromolecule Feedstocks to Higher-Value Fuels and Chemicals, filed on Oct. 15, 2020, the contents all of which are incorporated herein by reference in their entireties for all purposes.

This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/683,142, entitled System and Method for Converting Waste Polyolefins and Renewable Oils to Aromatic Compounds, filed on Aug. 14, 2024, and of U.S. Provisional Patent Application Ser. No. 63/750,098, entitled Method and Apparatus for Converting Low-Value Macromolecule Feedstocks to Higher-Value Fuels and Chemicals, filed on Jan. 27, 2025, the contents both of which are incorporated herein by reference in their entireties for all purposes.

This invention relates to hydrocarbon processing, and more particularly to systems and methods for efficiently producing high value products such as transportation fuels from lower value feedstocks.

Aromatic compounds are important as platform chemicals that serve as feedstocks for industrial and consumer applications. Ranking high in importance are benzene and its mono-, di-, and tri-substituted variants in which the substituents are alkyl groups comprising one, two, or three carbons, e.g., toluene, xylenes, mesitylene, ethylbenzene, and cumene; and alkyl benzenes bearing a single, larger substituent, e.g., various linear alkyl benzenes and alkyl toluenes. Ethylbenzene is particularly important as a precursor to styrene, which has enormously broad application in plastics, paints and coatings, synthetic rubbers, polyesters, to name but a few. Whereas catalyzed alkylation of benzene is the principal commercial route to ethylbenzene and to linear alkylbenzenes used in production of surfactants and emulsifiers, catalytic reforming of naphtha, e.g., in petroleum refineries, is the principal source of low-molecular-weight (low-MW) aromatics represented by benzene, toluene, ethylbenzene, and xylenes (BTEX). (For convenience, the term BTEX will be understood hereinafter as denoting as a class low-MW aromatics with 10 or fewer carbons.)

While conventional feedstocks for producing such aromatics include petroleum and natural gas liquids, the growing emphasis on renewable sources and economic circularity motivates the search for alternative ways to produce platform chemicals generally, and low-MW aromatics in particular. Accordingly, a range of methods has been investigated for doing so through conversion of biomass-derived materials, renewable oils, and plastics in municipal solid waste (MSW) streams including post-use plastics (PUP). Though details vary and generalizations have limitations, such conversion of biomass and PUP commonly involves relatively complex multi-step approaches that are generally not amenable to as-is catalytic transformation.

Desiring to circumvent conventional multi-step approaches, some have sought ways for what may be regarded nominally as producing aromatic compounds directly from polyolefins, e.g., polyethylene (PE) and polypropylene (PP). (For convenience, the abbreviation PEPP will be used hereinafter to denote post-use polyolefins generally, from PE that is substantially free of PP or vice versa to mixtures containing substantial amounts of each; and PE or PP will be understood to denote the named polyolefin containing relatively low levels of contaminants generally.) Conditioned generally on availability of PEPP containing relatively low levels of contaminants, such direct approaches are thermocatalytic, i.e., they involve the operation of catalyst at elevated temperatures with the aim to promote diverse reactions concurrently or sequentially, while incurring minimal yield loss due to side reactions that produce coke and low-molecular-weight hydrocarbons. Apart from the requirement to generate tractable, lower-molecular-weight compounds from PEPP feedstocks, their conversion to aromatic compounds involves conditions akin to those employed in naphtha reforming: application of temperatures above about 450° C.; catalysts typically configured with platinum or palladium; and elevated partial pressures of molecular hydrogen generated through aromatization or addition from external sources, which suppresses coking. In a related approach for converting PE to aromatics, Zhang et al. (Science, 2020) again applied a catalyst of platinum on a solid support, captured and applied molecular hydrogen produced autogenously, yet the conversion rates achieved were relatively low.

Although BTEX from biomass is a compelling concept, the chemical route is arduous, making renewable oils isolated from oil seeds a compelling alternative to other non-petroleum feedstocks. In view of chemistry and process engineering, these triglycerides represent a favorable starting point due to (i) the ease of isolating them in relatively high purity; (ii) the relatively low molecular weight of their constituent fatty acids; (iii) the high aliphatic hydrocarbon content represented in the fatty acid chains; and (iv) low amounts in them of other chemical functionality besides carboxyl. Yet, the latter presents a problem typical of renewable feedstocks: the presence of oxygen in a form that stubbornly resists straightforward elimination to yield oxygen-free hydrocarbons. As a practical matter, catalytic means are required to eliminate oxygen from fatty acids through decarboxylation or decarbonylation.

This imposes a twofold requirement for producing BTEX from renewable oils: deoxygenation and cyclization-aromatization. One possible approach would be to, first, effect the substantially quantitative deoxygenation of fatty acids and obtain hydrocarbons corresponding to their carbon chains, as taught by Trygstad et al. in U.S. Pat. No. 11,414,606; and second, convert the hydrocarbons to BTEX by conventional means similar to naphtha reforming. Yet, a condition for the economic production of BTEX by such a two-step process is the uninterrupted availability of feedstock to support continuous operation of a reformer, as in petroleum refineries. Moreover, refineries make good use of the large quantities of byproduct hydrogen generated by reformer units whereas, in the absence of petrochemical infrastructure, it would have to be flared if not used as a fuel to provide heat for the reforming units or recovered as a green hydrogen source. Alternatively, the fatty-acid-derived hydrocarbons could be co-fed with petroleum naphtha in a refinery, yet that would compromise objectives of renewability. In view of the foregoing, the inventors of the instant invention recognized the need for a system and method that addresses drawbacks of the existing art.

In one aspect of the invention, a process is provided for transforming aliphatic moieties in feedstocks into aromatic compounds. The feedstocks contain aliphatic moieties and at least about 12 carbon atoms, with each of the aliphatic moieties including at least six constituent carbon atoms disposed in a contiguous open-chain configuration, with each of the constituent carbon atoms bearing no more than one aliphatic substituent. A first process agent includes one or more metals disposed on a substrate consisting of oxides of: aluminum; silica; titanium; zirconium; and/or combinations of aluminum and silica. The first process agent is disposed in the reactor in contact with the feedstocks to form a process mixture. The process mixture is maintained at temperatures in a range T(range) of about 325° C. to 450° C., to effect commencement of one or more desirable reactions. The process mixture is maintained at T(range) for a residence time of about 0.1 hours up to about 5 hours, to further promote the desirable reactions in the process mixture to generate products containing aromatic compounds. The aromatic compounds are generated independently of any requirement for adding molecular hydrogen to the process system or for configuring the process system to deliberately accumulate and/or maintain a partial pressure of molecular hydrogen, and are recovered from the process mixture.

In another aspect of the invention, a system for transforming aliphatic moieties in feedstocks into aromatic compounds includes a reactor sized and shaped to receive one or more feedstocks containing aliphatic moieties and at least about 12 carbon atoms, with each of the aliphatic moieties including at least six constituent carbon atoms disposed in a contiguous open-chain configuration in which each of the constituent carbon atoms bears no more than one aliphatic substituent. The system includes a first process agent including one or more metals on a substrate consisting of oxides of: aluminum; silica; titanium; zirconium; and/or combinations of aluminum and silica. The reactor is configured to maintain the feedstocks in contact with the first process agent to form a process mixture. The reactor is configured to maintain the process mixture at temperatures in a range T(range) from about 325° C. to 450° C., to effect commencement of one or more desirable reactions. The reactor is configured to maintain the process mixture T(range) for a residence time of about 0.1 hours up to about 5 hours, to further promote the desirable reactions in the process mixture to generate products containing aromatic compounds. The system is configured to recover, from the reactor, the aromatic compounds, wherein the aromatic compounds are generated independently of any requirement for adding molecular hydrogen to the process system or for configuring the process system to deliberately accumulate and/or maintain a partial pressure of molecular hydrogen.

The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.

In the following detailed description, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration, specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized. It is also to be understood that structural, procedural and system changes may be made without departing from the spirit and scope of the present invention. In addition, well-known structures, circuits and techniques have not been shown in detail in order not to obscure the understanding of this description. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

Extant art for producing BTEX from post-use polyolefins, biomass, or renewable oils typically involves sequential application of a plurality of distinct chemical conversion processes. The approach of Zhang et al is a notable exception yet it (i) is focused on polyolefins; (ii) has yet to be demonstrated at scale, possibly because of long conversion times (e.g., 24 hours); and (iii) has uncertain to tolerance contaminants in real-world, post-use waste plastics. The inventors of the system and method described hereinbelow saw a need for and understood the commercial and environmental benefit of capability to transform a broader range of feedstocks into aromatic compounds in a single conversion unit (e.g., reactor) without requiring catalyst prepared with expensive (e.g., noble) metals, application of molecular hydrogen at elevated pressures, and elevated pressures. Accordingly, aspects of the present invention include a novel and non-obvious process whose distinctive features include,

The present invention addresses the need for the capability of producing aromatic compounds, which, compared with extant art, is simpler, less complex, and less costly while also being able to convert diverse feedstocks other than those derived from petroleum, including those with oxygen-containing groups. In summary, the inventive embodiments (system and method) produce aromatic compounds from aliphatic moieties in feedstock compounds in a single step at temperatures and in time frames that are relatively low, yet without requiring Pt-, Pd-, Ir-, or Rh-based catalysts or addition/accumulation of molecular hydrogen.

As used in the specification and in the appended claims, the term ‘aliphatic moieties’ refers to portions of organic compounds characterized by having at least six carbon atoms linked by single or double bonds in a contiguous open-chain configuration, either straight or branched, rather than in cycloaliphatic or aromatic rings, e.g., six-membered cyclohexane, cyclohexene, or benzenoid moieties. And the term ‘aromatic compound’ refers herein to compounds having a single, six-membered aromatic ring (a benzenoid ring), wherein: (i) each carbon atom in the ring bears either hydrogen or a substituent; (ii) a plurality of substituents can occupy any of the positions on the ring; and (iii) a substituent is any aliphatic group taken from the group consisting of: (a) methyl, ethyl, and larger alkyl groups containing three to about 20 carbon atoms; and/or (b) alkenyl groups consisting of two to about 20 carbon atoms and at least one unsaturation. The term ‘low-molecular-weight (low-MW) aromatics’ refers to aromatic compounds wherein the total number of carbons in all substituents is zero to about 25. Unless otherwise indicated, all percentages are understood to be weight (mass) percentages.

The term ‘renewable oils’ refers to fatty acid glyceryl esters (FAGE) from plant and animal sources, including mono-, di-, and tri-acyl glycerols. The former includes vegetable oils from (i) oil seed crops, certain fruits such as jojoba and jatropha, and beans such as soy and castor; (ii) post-use cooking oil, or waste cooking oil (WCO); and (iii) the byproduct from ethanol produced by corn fermentation, called corn distillers oil (CDO). FAGE from animal sources is obtained by rendering of animal fat. Fatty acid types and distributions in the FAGE vary widely with the source but typically have carbon chains containing about 14 to 22 carbons and zero to three unsaturations, where stearic, oleic, linoleic, and linolenic acids are representative 18-carbon examples with zero, one, two, and three unsaturations, respectively. The term ‘renewable feedstocks’ as used herein includes FAGE, fatty acids derived from them, and alkyl esters derived from FAGE or free fatty acids (FFA) through transesterification or esterification, respectively, with simple alcohols such as methanol, ethanol, propanol, and butanol. The term ‘PEPP-derived wax’ refers to products obtained by chemolytic deconstruction of PE and/or PP according to the system and method described previously by Trygstad et al. (the above-referenced U.S. Ser. No. 17/494,360), where the product consists of substantially-saturated lower-MW hydrocarbon compounds containing about 25 to 250 carbon atoms whose structures relate substantially to that of PE or PP, e.g., straight-chain alkanes and methyoligopropylene alkanes, respectively, where the latter may be referred to more precisely as quaque altera carbonis methylated alkanes (qoc-methylated alkanes). For simplicity, these waxes may be regarded as consisting of oligomers of PE and/or PP. And paraffinic crude oil refers to crude oils that substantially consist of paraffinic hydrocarbons and include by way of nonlimiting example Uinta Basin Crude.

The singular forms “a”, “an”, and “the” include plural referents unless the context clearly indicates otherwise. For example, reference to “an analyzer” includes a plurality of such analyzers. In another example, reference to “an analysis” includes a plurality of such analyses.

Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. All terms, including technical and scientific terms, as used herein, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs unless a term has been otherwise defined. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning as commonly understood by a person having ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and the present disclosure. Such commonly used terms will not be interpreted in an idealized or overly formal sense unless the disclosure herein expressly so defines otherwise.

Referring now to the Figures included herein, aspects of the present invention will be described, which relate to operation and enablement of particular embodiments.

Process Agents and Reactions. Referring to, though wishing to not be bound by any particular theory of operation, embodiments of the present invention are believed to convert aliphatic moieties in the feedstock compounds to aromatic compounds by promoting, in a reactor, four desirable reactions through the operation of process agents PA, PA, and PA, which are, respectively a catalyst, water, and a mobile phase. The catalyst promotes the conversion by first, second, and third desirable reactions; water promotes desirable reactions of the fourth type, in which water is a reactant; and the mobile phase facilitates mass transfer in the reactor and, in particular embodiments, it also facilitates heat transfer.includes representative process agents and their purpose whiledetail four desirable reactions D-D() as well as the undesirable reactions U (), which result in yield loss due to byproduct formation.

Catalyst. Referring to, in particular embodiments, the first process agent (PA) is a catalyst consisting of one or more metals disposed on a substrate, where (i) the one or more metals are selected from the group consisting of (a) metals in groups-of periods,, andof the periodic table of the elements excluding platinum and palladium, and (b) lanthanides; and (ii) the substrate consists of oxides of aluminum, and/or oxides of silicon, and/or oxides of titanium, and/or oxides of zirconium, and/or combinations of oxides of aluminum and silicon.

As regards the one or more metals, particular embodiments dispose each on the substrate in amounts of about 1% to 16% versus the substrate. In other particular embodiments, the metal is nickel or molybdenum in amounts of about 5% to 10%, whereas in yet other particular embodiments, the metal consists of molybdenum and nickel, each in amounts of about 1% to 8%. In further particular embodiments, the one or more metals on the substrate are in the form of an oxide, e.g., NiO and MoO, whereas in other particular embodiments they are in elemental form (oxidation state is zero).

As regards the substrate, in particular embodiments, it includes first compounds, which are aluminosilicates including M[(AlO)(SiO)]·zHO and/or M[(AlO)(SiO)]·zHO, wherein W, x, y, and z have values of, respectively, 0 to about 10, about 2 to 25, about 2 to 100, and 1 to about 40; and M is one or more cations corresponding to elements taken from groups I and II of the periodic table of the elements, including hydrogen (H), sodium (Na), potassium (K), calcium (Ca), magnesium (Mg), and/or barium (Ba). Such first compounds include various clays including but not limited to bentonite clay, kaolin clay, and/or montmorillonite clay; and zeolites including by way of nonlimiting example Zeolite-A, Zeolite-Y, Beta Zeolite, and ZSM-5. In particular embodiments, the value for w in first substrate compounds is zero and the aluminosilicate compounds are aluminum silicates with the general formula (AlO)(SiO)·zHO. And in particular embodiments where w=x=z=0 or w=y=z=0, second substrate compounds are, respectively, silica or alumina, which are oxides of aluminum and silicon. In other particular embodiments, the substrate includes second compounds, which are oxides of titanium and zirconium (titanium dioxide, TiO, and zirconium oxide, ZrO, respectively). Yet another particular embodiment includes a third substrate compound, zirconia, which is zirconium silicate (ZrSiO).

In particular embodiments the composition of the catalyst is configured to optimize its operation in consideration of (i) properties of feedstocks including the propensity of compounds in them to undergo conversion via desirable reactions; (ii) the presence in feedstock compounds of oxygen-containing functionality, e.g., hydroxyl and carboxyl, and the requirement to eliminate the same; and (iii) temperatures of operation. Such configuration includes the selection of the one or more metals deposited on the substrate; the amounts deposited; selection of the metal form as elemental or oxide; and properties of the substrate including its effect on activity of metals deposited thereon.

Representative Structures of Feedstocks and Products. Turning now to, an inventory of representative aliphatic moieties is shown, which may either exist in feedstocks or in intermediate products formed through desirable reactions of the first type. The inventory is illustrative and is not intended to the exhaustive; rather, its purpose is to indicate (i) types and varieties of six- and seven-carbon, open-chain aliphatic structures in feedstocks (e.g., “Base Structure”) that embodiments of the present invention convert to aromatic compounds; and (ii) corresponding aromatic compounds (e.g., “Product”). Axiomatically, in none of various open-chain aliphatic moieties depicted indoes any of six carbon atoms disposed in a contiguous open-chain configuration, which eventually form the six-membered aromatic ring in product compounds, have more than one alkyl substituent. For, whereas an aliphatic moiety containing a quaternary carbon (one that bears two substituents excluding bonds to adjacent carbons in the six-carbon chain) could undergo cyclization to form a six-membered cycloaliphatic moiety, its inability to lose a hydrogen precludes subsequent aromatization.

Though wishing to not be constrained by any particular theory of operation,is a nonlimiting depiction of desirable reactions D-Din feedstock compounds represented by a polyolefin consisting of a saturated carbon chain whose backbone contains greater than about 25 carbons. The caption, ‘I. Homolytic cleavage of C—C bond and subsequent reactions generating intermediate hydrocarbons’, is indicative of a shown reaction of the first type, D, that obtains shorter fragments from longer-chain compounds via bond scission that is homolytic but may occur by other mechanisms. The caption, ‘II. Cyclization and aromatization of intermediate hydrocarbons’, relates to the corresponding figure depicting an outcome that may be obtained substantially either directly from representative open-chain aliphatic structures by desirable reactions of the third type or by sequential operation of desirable reactions of the second and third types.

Representative Feedstock Compounds. Having discussed the aliphatic moieties on which embodiments of the present invention operate, we now consider representative feedstocks within which the aliphatic moieties may be found.presents such representative feedstocks, where PE=polyethylene, PP=polypropylene, and EVOH=poly(ethylene-co-vinyl alcohol) or simply ethylene-vinyl alcohol copolymer. Whereas the qoc-methylated alkane structure is uncommon apart from PP, the straight-chain structure of PE is common in compounds of other feedstocks. Whereas the term polyethylene connotes its origin through polymerization of ethylene, the structure labeled PE is more aptly described as polymethylene. Not wishing to be constrained by any particular theory of operation, such straight-chain aliphatic moieties are substantially the same as those found in feedstocks of particular embodiments, e.g., in (i) paraffinic crude oil, e.g., Uinta Basin Crude; (ii) hydrocarbon chains of fatty acids in renewable oils and derivatives of the same; and (iii) EVOH. Moreover, the labels PE and PP inshould be understood to refer not only to polymers in plastics, whose carbon numbers typically exceed 2000 but also include shorter-chain oligomers obtained from them, e.g., chains of about 25 to 250 carbons, by chemolytic deconstruction of PE and PP according to Trygstad et al. (the above-referenced U.S. Ser. No. 17/494,360). Accordingly, the labels PE and PP inare descriptive, denoting functionality and not being limiting as regards either carbon number or the feedstock in which the functionality resides.

Desirable and Undesirable Reactions. Notable aspects of the embodiments discussed herein, including their versatility for converting aliphatic moieties in diverse feedstocks, and their ability to do so without the need to add molecular hydrogen, include: (i) the use of relatively mild process temperatures; (ii) the configurability of the catalyst to promote desirable reactions D-Dsubstantially selectively; and (iii) the benefit of water in either suppressing undesirable reactions or mitigating their consequences. Referring now to, the operation of water in desirable reaction Dis beneficial in particular embodiments whose feedstock includes FAGE, as it predisposes the fatty acids produced to undergo desirable reactions Dand/or Dlc; converts the other hydrolysis product, glycerol, to reducing equivalents via D; and suppresses undesirable reaction Uand subsequently U, the product of which converts to carbonaceous material. Such carbonaceous material and incipient forms thereof may form by other means, e.g., by U-U; has general formula C Hy where u/v>about 1.25; and it can deactivate PA, reduce product yields from feedstocks, and accumulate in the product mixture as a solid byproduct.

Without wishing to be constrained by particular theories of operation,elaborate on bases for representative reactions D-D. In that regard, the significance of reaction Dis twofold. First, it operates on aliphatic moieties in feedstock compounds to obtain two intermediate product compounds that also contain aliphatic moieties capable of undergoing conversion to aromatic compounds. Second, through its successive operation on the selfsame intermediates, Dgenerates a plurality of yet-shorter intermediate compounds. This aspect of the instant invention is especially beneficial in embodiments wherein feedstocks consist of compounds with greater than 25 carbon atoms disposed in a contiguous open-chain configuration, e.g., polyolefins; waxes derived therefrom, which contain 25 to about 250 carbon atoms; and paraffinic crude oils. The operation of Dis likewise possible in embodiments wherein the feedstocks are renewable oils and/or fatty acids derived therefrom or the corresponding alkyl esters. Yet, wishing again to not be constrained by any particular theory of operation, unsaturations in the fatty chains predispose them to directly undergo reactions Dand/or Dto directly form aromatic compounds. And in the event that Doperates on such fatty chains, Dand/or Dcan operate on resulting intermediates that have six or more carbon atoms to yield aromatic compounds such as benzene, toluene, ethylbenzene, xylenes, and the like.

Water and Mobile Phase. Particular embodiments convey third process agent PAinto the reactor to promote the dispersal of feedstocks, the contacting of the same with PA, and the obtaining thereby of a reaction mixture; and to beneficially promote mass transfer and heat transfer. Water is well-suited for this purpose, given its high heat capacity and thermal conductivity, and molecular mobility, and improved physico-chemical properties at elevated temperatures including lower dielectric constant and dipole moment, and higher diffusion coefficient. Thus, particular embodiments include PAas water in amounts beyond those corresponding to the stoichiometric demand for PAin respect of desirable reactions D. In particular embodiments, PA(PA) is supplied in amounts of about 0.1 to 1.5 relative to feedstock mass. PAin the form of hydrocarbons and carbon dioxide offer other advantages compared with water, e.g., they are thought to be a more effective agent for dispersing feedstocks due to their lower polarity, dielectric constants, and dipole moments. Accordingly, particular embodiments supply PAin only a slight excess of the demand for water corresponding to reactions Dand the undesirable reaction Udescribed in, respectively; and also supply PAas one or more compounds from the group consisting of carbon dioxide, one or more alkanes containing three to five carbons, and one or more aromatic compounds containing nine or fewer carbons including benzene and mono-, di-, and tri-methybenzenes. The amount of PAis about 1.1 to 1.5 times the stoichiometric demand corresponding to any or all of reactions Dand U; and the amount of PAis about 0.1 to 1.5 relative to feedstock mass.

In particular embodiments wherein the process system includes a tubular reactor containing PAdisposed as a fixed bed, the rates at which feedstock and PAis conveyed into the reactor ae controlled to provide a residence time for the reaction mixture of about 0.5 to 4 hours

Other Desirable Reactions: Deoxygenation. An important aspect of the instant invention relates to its capability to eliminate oxygenated functionality embedded in or appended to aliphatic moieties that undergo conversion to aromatic compounds. In particular embodiments, at least one of the least six constituent carbon atoms disposed in a contiguous open-chain configuration of the aliphatic moieties bears a carboxylate group or a hydroxyl group. Referring again to, desirable reactions Dand/or Deliminate a carboxylate group appended to an aliphatic moiety through decarboxylation and/or decarbonylation. In yet other particular embodiments, at least one carbon atom in an aliphatic moiety bears a hydroxyl group, which is eliminated through dehydration as depicted in desirable reactions D. Whether spontaneous or by operation of PA, the result of each dehydration event is formation of an unsaturation, which predisposes the resulting intermediate product to undergo subsequent reactions Dand Dthat generate aromatic compounds.

Yet, in the specific case of EVOH, a high density of hydroxyl functionality in the polymer chain would result in a correspondingly high density of unsaturation in the dehydrated polymer, which, rather than being predisposed to undergo desirable conversion to aromatics via reactions Dand D, might instead yield to undesirable reactions U-Uthat produce carbonaceous byproducts and, ultimately, coke, resulting in PAdeactivation and yield loss. Accordingly, in embodiments of the instant invention, EVOH consists of ethylene and vinyl alcohol in a ratio of (moles vinyl alcohol)/(moles ethylene) that is less than about 0.35.

Representative Aromatic Compounds Produced. The description of aromatic compounds provided above covers all that are produced by various embodiments of the present invention described below. Yet, the range of such aromatic compounds in product mixtures of the various embodiments varies according to aspects of the embodiments including feedstock; the configuration of PA; operating conditions such as temperature and residence time of feedstock conversion; amounts of PAand PArelative to feedstock; and the composition of PA. More specifically, variations in these aspects of embodiments affect the composition of aromatic compounds in product mixtures in respect of (i) the number of substituents on the benzenoid ring, which can range from zero to six; (ii) and for a plurality of substituents, their relative positions on the ring; (iii) the size of the substituents, which can consist of from one to about 20 carbon atoms; (iv) the structure of the substituents; (v) the presence of unsaturations in substituents; and (vi) the relative amounts of the various aromatic compounds, e.g., the distribution of aromatic compounds in the product mixture.

Though wanting to not be bound by any particular theory of operation, the number, size, and relative positions of substituents in aromatic products relates to the structure of feedstock compounds. Referring now to, the representative feedstocks depicted there all consist of carbon atoms disposed in a contiguous, open-chain configuration, yet only in PP does the carbon chain have alkyl substituents, e.g., it has a qoc-methylated alkane structure. (As discussed immediately above, the hydroxyl substituents on ricinoleic acid and PVOH undergo elimination in particular embodiments by the mechanism of dehydration.) Accordingly, and turning now to, aromatic compounds obtained from PP are expected to exhibit a plurality of methyl groups on alternating carbons in the benzenoid ring, and alkyl substituents larger than methyl will be expected to exhibit the qoc-methylated alkyl structure of parent compound.

Referring now to, and again wishing to not be constrained by particular theories of operation, these figures relate by way of nonlimiting examples the relationship between structures of feedstock and aromatic compounds produced from them. Thus, aromatic compounds shown as products of feedstocks with carbons that are in a linear configuration, without alkyl substituents, are shown as having either one substituent or two substituents on adjacent carbons in the aromatic ring. Yet, in embodiments of the present invention wherein the feedstocks do not include PP, aromatic compounds produced include those having more than two substituents, three being common while more are possible, which may be explain straightforwardly as the result of alkyl group migration that occurs in connection with first, second, and third desirable reactions, with and without facilitation by PA.

In particular embodiments where the feedstock is a renewable oil and/or fatty acids derived therefrom, including ricinoleic acid, and/or alkyl esters of the same, aromatic product compounds predominantly include benzene and mono- and di-alkylaromatic compounds whose total carbon number is (i) nine or less, such as toluene, xylenes, ethylbenzene, cumene, and mesitylene; and (ii) greater than or equal to 10, and one or more substituents is an alkyl group or an alkylene group containing three or more carbons. This same suite of aromatic compounds is produced by particular embodiments wherein the feedstock is PE, wax derived from PE, paraffinic crude oil, and EVOH. By contrast, in particular embodiments wherein the feedstock includes PP, aromatic product compounds predominantly include di- and tri-alkylaromatics including but not limited to xylenes, mesitylene, ethyltoluene, ethylxylene, methylcumene, ethylcumene, and the like.

A Fourth Process Agent. Turning now to, an inventory of representative desirable reactions of a fourth type, D, is shown, all of which consume water. Reactions Dand Ddepict the net reaction of water with the hydroxylated compounds glycerol and ethanol, respectively, to yield carbon dioxide and reducing equivalents denoted as molecular hydrogen.

Ethanol and glycerol are, respectively, nonlimiting examples of monohydric and monohydric and polyhydric alcohols. In particular embodiments, the latter are perhydroxylated compounds in which each carbon atom in a saturated compound bears a hydroxyl group; ethylene glycol is a further example; and methanol is the trivial case (one carbon, one hydroxyl) that also is representative of simple alcohols that include ethanol by way of nonlimiting example. Renewable oils include triglycerides, which under process conditions undergo hydrolysis to yield free fatty acids and glycerol. However, where glycerol is not inherent in the feedstock, particular embodiments enrich the reaction mixture with reducing equivalents generated through in situ aqueous reforming (AR) of an added fourth process agent PAtaken from the group consisting of, alcohols including but not limited to methanol and ethanol; and polyhydric compounds including but not limited to ethylene glycol and glycerol. Though wishing to not be constrained by any particular theory of operation, such enrichment is thought to enhance suppression of coke formation and associated diminishment of catalyst activity by moderating the rates of alkene formation, e.g., by reactions Dand D-D, through quenching according to reaction D. This is thought to improve selectivity toward intramolecular cyclization and aromatization by Dand Dover intermolecular dimerization/polymerization and subsequent coke formation. Thus, PAmay be optionally added in any embodiment of the present invention, and although doing so is unlikely to substantially impact overall conversion yields, it offers the means to improve overall process reliability.

As described previously by Trygstad et al. (the above-referenced U.S. Ser. No. 17/494,360), the operation of AR, in particular embodiments that apply PA, generates reducing equivalents, which are hydrogen equivalents denoted [H]. Though not wishing to be constrained by particular theories of operation, it is believed that [H] exist in a latent form, e.g., in an intermediate produced by reaction between water and PA, which is able to donate atomic hydrogen (a hydrogen equivalent). Though plausible that AR of PAproduces molecular hydrogen, benefits from intrinsic or added PAin particular embodiments accrue substantially by operation of [H], as the possibility for reduction by His limited due to (i) the low partial pressure of any that may form, and (ii) the absence of catalyst suitable to activate its reaction, e.g., catalysts consisting of platinum (Pt), palladium (Pd), iridium (Ir), or rhodium (Rh), disposed on a substrate. Thus, in contrast with extant art, which adds or accumulates molecular hydrogen in the process apparatus and relies on catalysts configured with Pt to activate its reaction, [H] generated from PAin embodiments of the present invention react directly without mediation by such catalysts.

Having described representative feedstocks, aliphatic moieties contained therein, reactions that convert those moieties to aromatic compounds, and process agents that promote those conversions, particular embodiments of the present invention are now described.

As shown in, various embodiments of the instant invention effectively transform aliphatic moieties in feedstocks into aromatic compounds by use of:

Particular embodiments also include:

As shown and described hereinabove, the embodiments using tubular reactors (e.g., flow-through reactor′ of) are configured to operate at a pressure range at the outlet of about ambient pressure to about 200 psi. Such embodiments also rely on application of a third process agent PAthat functions as a mobile phase that motivates the flow of the reaction mixture downstream from the reactor inlet and through the PAfixed bed, where PAmay be water or a hydrocarbon, as described previously. Alternatively, the embodiments using stirred tank reactors (e.g., batch reactorof) are configured to operate at a pressure greater than about 200 psi and up to about 2000 psi, and in particular embodiments, at a range from about 500 psi to about 1500 psi. Such embodiments do not necessarily depend on the inclusion or operation of a third process agent PAas water or hydrocarbons, although it may beneficially enhance mass transfer, e.g., the dispersal and contacting of feedstocks with PAand PA; yet the inclusion and operation of

PAremains important in such embodiments, e.g., in relation to reactions Dand U, some or all, as the case may be.

A feedstock of fatty acids derived of renewable oils including corn distiller oil and waste cooking oil was fed to a closed, stirred tank reactor with a catalyst consisting of 7.5% molybdenum oxide on ZSM-5. The feedstock was charged into the reactor together with the catalyst, water, and glycerol, each in amounts of 0.1 relative to feedstock mass. Under stirring to promote contacting of the feedstock with catalyst and water, the resulting reaction mixture was heated to 360° C. where pressure increased autogenously to 1200 psi. After a residence time of 4 hours, conversion obtained a liquid product mixture in 77% yield versus the supplied feedstock (normalized for COloss), which contained 83% aromatic compounds (by weight). Aromatic compounds in the aromatics fraction consisted of 10% benzene; 28% toluene; and C, C, and Caromatics in amounts of 37%, 7%, and 18%, respectively. Note: As used in Examples 1-6: C=xylenes, ethylbenzene; C=ethyltoluene, propylbenzene, mesitylene; C=tetramethylbenzene, diethylbenzene, methylpropylbenzene, dimethylethylbenzene, and butylbenzene; C=ethylpropylbenzene; C=1,3,5-triethylbenzene, ethylbutylbenzene.

A feedstock of fatty acids derived of renewable oils including corn distiller oil and waste cooking oil was fed to a tubular reactor which included a fixed-bed catalyst consisting of 7.5% molybdenum oxide on ZSM-5 configured as a fixed bed in the reactor. Water was mixed with the feedstock at a weight ratio of 0.5:1, respectively, and conveyed continuously into the catalyst fixed bed through the reactor inlet; the temperature in the reactor was 360° C.; the feed rate for the feedstock/water was controlled to provide an average residence time in the reactor of 3 hours; and the pressure at the reactor outlet was maintained below 100 psi. Conversion obtained a liquid product mixture at the reactor outlet in 83% yield versus the supplied feedstock (normalized for loss of glycerol and CO), which contained 83% aromatics. Aromatic compounds in the aromatics fraction consisted of 9% benzene; 16% toluene; and C, C, and Caromatics in amounts of 56%, 5%, and 14%, respectively.

A feedstock of fatty acid triglycerides in waste cooking oil and/or corn distiller oil was fed to a tubular reactor which included a fixed-bed catalyst consisting of 7.5% molybdenum oxide on ZSM-5 configured as a fixed bed in the reactor. Water was mixed with the feedstock at a weight ratio of 0.1:1, respectively, and conveyed continuously into the catalyst fixed bed through the reactor inlet; the temperature in the reactor was 370° C.; the feed rate for the feedstock/water was controlled to provide an average residence time in the reactor of 3 hours; and the pressure at the reactor outlet was maintained below about 100 psi. Conversion obtained a liquid product mixture at the reactor outlet in 77% yield versus feedstock (normalized for loss of glycerol and CO), which contained 66% aromatics (by weight). Aromatic compounds in the aromatics fraction consisted of 5% benzene; 19% toluene; and C, C, and Caromatics in amounts of 29%, 13%, and 34%, respectively.

A feedstock of post-use (waste) polyolefin containing polyethylene (PE) was fed to a closed, stirred tank reactor along with a catalyst consisting of 5% nickel oxide and 2.5% molybdenum oxide on ZSM-5. The feedstock was charged into the reactor together with the catalyst, water, and glycerol in amounts relative to feedstock mass of.,., and., respectively. Under stirring to promote contacting of the feedstock with the catalyst, water, and glycerol, the resulting reaction mixture was heated to 370° C. where pressure increased autogenously to 1000 psi due to water and the accumulation of low-MW product compounds. After a residence time of 4 hours, conversion obtained a liquid product mixture in a 71% yield versus feedstock, which contained 38% aromatics. The aromatics in the aromatics fraction consisted of 2% benzene; 12% toluene; and C, C, and Caromatics in amounts of 31%, 28%, and 27%, respectively.