WO2021056087A1

WO2021056087A1 - Recycled hexane and uses thereof

Info

Publication number: WO2021056087A1
Application number: PCT/BR2020/050375
Authority: WO
Inventors: Pedro Luis INVERNICI; Edmundo Ferreira BARROS FILHO; Iuri FREYTAG; Fernanda Silveira Ribaski DE BORBA; Luiza Roza
Original assignee: Braskem S.A.
Priority date: 2019-09-23
Filing date: 2020-09-22
Publication date: 2021-04-01
Also published as: BR112022005351A2

Abstract

A purified hexane waste may include n-hexane, one or more isomers of hexane, one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water, monochloroethane, ethanol, and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes, non-C6 alkenes.

Description

RECYCLED HEXANE AND USES THEREOF

BACKGROUND

[0001] Solvents play an important role being used in many diverse applications such as paints and coatings, adhesives, inks, thinners, personal care and household products. They are also heavily used industrially as, for example, a reaction medium or as an extractant.

SUMMARY

[0002] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0003] In one aspect, embodiments disclosed herein relate to a purified hexane waste that includes n-hexane in an amount ranging from 55 to 75% by mass; one or more isomers of hexane in an amount ranging from 5 to 40% by mass; one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water in an amount that is less than 300 ppm; monochloroethane in an amount of less than 1.5%; ethanol in an amount of less than 1000 ppm; and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes and non-C6 alkenes. [0004] In another aspect, embodiments disclosed herein relate to an adhesive composition that includes at least one resin; and a solvent system that includes a purified hexane waste recycled from olefin polymerization reactions.

[0005] In another aspect, embodiments disclosed herein relate to a method of adhering two articles together that include applying an adhesive composition to at least one of the two articles; and bringing the two articles into contact with each other, thereby adhering the two articles together. The adhesive composition may include at least one resin; and a solvent system comprising a purified hexane waste that includes n-hexane in an amount ranging from 55 to 75% by mass; one or more isomers of hexane in an amount ranging from 5 to 40% by mass; one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water in an amount that is less than 300 ppm; monochloroethane in an amount of less than 1.5%; ethanol in an amount of less than 1000 ppm; and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes and non-C6 alkenes.

[0006] In another aspect, embodiments disclosed herein relate to a method of adhering two articles together that include applying an adhesive composition to at least one of the two articles; and bringing the two articles into contact with each other, thereby adhering the two articles together. The adhesive composition may include at least one resin; and a solvent system comprising a purified hexane waste recycled from olefin polymerization reactions.

[0007] In another aspect, embodiments disclosed herein relate to a method of extracting vegetable oil by solvent extraction from an oil-containing material that includes contacting the oil-containing material with a solvent system in an amount effective to accomplish the extracting, wherein the solvent system comprises a purified hexane waste recycled from olefin polymerization reactions.

[0008] In another aspect, embodiments disclosed herein relate to a method of extracting vegetable oil by solvent extraction from an oil-containing material that includes contacting the oil-containing material with a solvent system in an amount effective to accomplish the extracting, wherein the solvent system includes a purified hexane waste that includes n-hexane in an amount ranging from 55 to 75% by mass; one or more isomers of hexane in an amount ranging from 5 to 40% by mass; one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water in an amount that is less than 300 ppm; monochloroethane in an amount of less than 1.5%; ethanol in an amount of less than 1000 ppm; and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes and non-C6 alkenes.

[0009] In another aspect, embodiments disclosed herein relate to a method of extracting vegetable oil by solvent extraction from an oil-containing material that includes contacting the oil-containing material with a solvent system in an amount effective to accomplish the extracting, wherein the solvent system includes purified hexane waste recycled from olefin polymerization reactions.

[0010] In another aspect, embodiments disclosed herein relate to the use of a purified hexane waste recycled from olefin polymerization reactions in an adhesive composition or vegetable oil extraction.

[0011] In yet another aspect, embodiments disclosed herein related to a solvent system comprising at least one oxygenated compound and a purified hexane waste that includes n-hexane in an amount ranging from 55 to 75% by mass; one or more isomers of hexane in an amount ranging from 5 to 40% by mass; one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water in an amount that is less than 300 ppm; monochloroethane in an amount of less than 1.5%; ethanol in an amount of less than 1000 ppm; and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes and non-C6 alkenes.

[0012] In yet another aspect, embodiments disclosed herein related to method of cleaning a surface of an article that includes contacting the surface of the article with a solvent system that includes at least one oxygenated compound and a purified hexane waste that includes n-hexane in an amount ranging from 55 to 75% by mass; one or more isomers of hexane in an amount ranging from 5 to 40% by mass; one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water in an amount that is less than 300 ppm; monochloroethane in an amount of less than 1.5%; ethanol in an amount of less than 1000 ppm; and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes and non-C6 alkenes.

[0013] Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.

BRIEF DESCRIPTION OF DRAWINGS

[0014] FIG. 1 is a chart of a life-cycle-assessment that was conducted to compare the environmental performance of recycled hexane of the present disclosure with the conventional hexane. DETAILED DESCRIPTION

[0015] In one aspect, embodiments disclosed herein relate to the reuse of a purified hexane waste that, after a purification step, may be utilized either alone or in solvent systems for additional fields of application. The purified waste hexane described in accordance with one or more embodiments herein may be used for applications such as adhesive formulations, vegetable oil extraction, and solvent systems directed towards thinner applications for example. The purified hexane waste of one or more embodiments of the present disclosure may be obtained from hexane waste that results from polyethylene polymerization reactions.

[0016] High-density polyethylene (HDPE) polymerization may take place in slurry reactors wherein a catalyst (often Ziegler Natta catalysts) can be prepared in a slurry medium, with the same diluent that is used in the reactors. To prepare such catalysts for olefin polymerization, a stable inert diluent is often required to solubilize all liquid precursors for the catalyst, such as titanium tetrachloride (TiC ) and triethyl- aluminium (TEAL), and suspend the solid ones, such as magnesium ethoxide (Mg(OCH₂CH₃)₂). One commonly used diluent to prepare this slurry is hexane. Hexane wastes are thereby generated in this step, with reaction residues, and additional contaminants after the catalyst formation. Embodiments of the present disclosure relate to applying circular economy pillars of reuse, renewability, and minimizing resources to the hexane stream that is a waste stream of the polymerization process. Thus, embodiments of the present disclosure may improve sustainability in the conversion of hexane waste products into raw material for future application in other processes. While steps may conventionally be taken to recycle hexane back into a polymerization process (to increase purity of the stream), in one or more embodiments of the present disclosure, the hexane waste produced from the polyethylene production may be purified and recycled for other uses.

[0017] Specifically, in accordance with one or more embodiments of the present disclosure, a purified waste hexane may be utilized in applications such in vegetable oil extraction, solvent systems for adhesives and thinner applications instead of using traditional hexane produced in refineries by crude oil distillation. In spite of the presence of compounds that are not present in commercial hexane (suitable as polymerization grade hexane), the solvent described in this disclosure is able to perform as well as conventional hexane in those applications.

[0018] The hexane waste (recovered from a polyolefin polymerization) may be purified by a neutralization step with alkali metal compounds prior to use in accordance with the present embodiments. The product resulting from the neutralization may comprise in its majority, n-hexane and isomers thereof. In one or more embodiments, the purified waste hexane may comprise small amounts of C5 molecules and C7 molecules in addition to even lower amounts of C4 and C8+ molecules, monochloroethane and ethanol. In particular, a chromatographic profile of an exemplary purified hexane waste stream may include:

[0019] It may be appreciated, however, that the composition may vary according to source of hexane, the particular polymerization process from which the hexane waste is taken and the neutralization conditions to which the waste hexane was subjected. Despite that, the majority of C6 and the contaminants present in the hexane waste will remain the same.

[0020] In addition to the discussed organic compounds, the purified hexane waste product may also comprise some metal contaminants derived from the catalysts precursors and from chemicals used in purification step. The purification of the waste hexane may be accomplished via a neutralization step with alkali compounds where the final product may contain small amounts of water, which, for future polymerization purposes, may inhibit catalyst activity. However, such contaminants may not pose a problem for the applications described herein.

[0021] The purified hexane waste solvent described in one or more embodiments of the present disclosure may comprise n-hexane as a majority (or primary) component as well as one or more isomers of hexane. In one or more embodiments, the purified hexane waste may include one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof as well as water, and optionally, one or more secondary impurities from the group consisting of non-C6 alkanes, non-C6 alkenes, alkanols, and chloroethane.

[0022] The purified hexane waste solvent in accordance with embodiments of the present may be recycled from traditional hexane used in polymerization reactions as a diluent for catalyst. The purified waste hexane may comprise n- hexane in an amount ranging from a lower limit selected from 45%, 50%, 55%, 60%, and 65% by mass to an upper limit selected from 66%, 70%, 75%, 80%, and 85% by mass where any lower limit may be paired with any mathematically possible upper limit.

[0023] The purified hexane waste solvent in accordance with embodiments of the present disclosure may comprise one or more metals selected from alkali metals, alkaline earth metals, aluminum, and titanium. The purified waste hexane may comprise one or more of these metals in an amount ranging from a lower limit selected from 0.1 ppm, 1 ppm, 10 ppm, 50 ppm, 100 ppm, and 250 ppm to an upper limit selected from 500 ppm, 750 ppm, 900 ppm, 1000 ppm, and 1200 ppm where any lower limit may be paired with any mathematically possible upper limit.

[0024] The purified hexane waste solvent in accordance with embodiments of the present disclosure may include one or more isomers of hexane including 3- methylpentane, methylcyclopentane, 2-methylpentane, cyclohexane, 2,3- dimethylbutane and 2,2-dimethylbutane or a mixture thereof. The purified waste hexane may comprise one or more of the isomers in an amount ranging from a lower limit selected from 1%, 3%, 5%, 10%, 15%, 20%, and 25% by mass to an upper limit selected from 26%, 30%, 35%, 40%, 45%, 50%, and 55% by mass where any lower limit may be paired with any mathematically possible upper limit.

[0025] In one or more embodiments, the purified hexane waste in accordance with the present disclosure may have one or more secondary impurities are selected from the group consisting of non-C6 alkanes or alkenes (such as n- octane, n-butane, 3-methylheptane), monochloroethane, and ethanol, or a mixture thereof. The purified waste hexane may comprise one or more of the secondary impurities in an amount ranging from a lower limit selected from 0.001%, 0.01%, 0.05%, 0.1%, 0.2%, 0.5%, and 1% by mass to an upper limit selected from 1.5%, 2%, 2.5%, 3.0%, 3.3%, 4%, and 5% by mass where any lower limit may be paired with any mathematically possible upper limit. In particular, in one or more embodiments, the purified hexane waste in accordance with the present disclosure may comprise ethanol in an amount that is greater than Oppm and less than 1500 ppm in certain embodiments, less than 1200 ppm in other embodiments, less than 1000 ppm in some embodiments, and less 800 ppm in yet other embodiments. Further, in one or more embodiments, the purified hexane waste may comprise monochloroethane in an amount that is greater than 0% and less than 2.0% by mass in some embodiments, less than 1.5% by mass in other embodiments, and less than 1.0% by mass in yet another embodiment.

[0026] In one or more embodiments, the purified hexane waste in accordance with the present disclosure may comprise water in an amount that is greater than Oppm and less than 500 ppm in certain embodiments, less than 400 ppm in other embodiments, less than 300 ppm in some embodiments, and less 200 ppm in yet other embodiments.

[0027] Purified hexane waste solvent systems according to the present disclosure will generally possess physical properties suitable for the intended use of the solvent system and/or the compositions produced therefrom. One of ordinary skill in the art will, with the benefit of this present disclosure, appreciate that altering the relative amounts and/or identities of the components of a solvent system will influence the properties of the system.

[0028] SOLVENT SYSTEMS

[0029] One or more embodiments of the present disclosure pertain to solvent system compositions that may include a solvent system (containing one or more solvents) and optionally at least one solute. One or more embodiments of the present disclosure may be directed to solvent system that may be utilized in, or incorporated into, a vegetable oil extraction method, adhesive composition, or thinner and surface cleaning composition wherein the solvent system may comprise at least a purified hexane waste recycled from olefin polymerization reactions, including the purified hexane waste described above. In particular embodiments, the solute is fully dissolved in the solvent system. The solvent systems of one or more embodiments may also be used in cleaning compositions, printing inks, varnishes, adhesives, lacquers, or thinners.

[0030] In particular, one or more embodiments of the present disclosure may be directed to an adhesive composition, thinners and/or surface cleaner compositions comprising a solvent system that comprises purified hexane waste that is present in an amount ranging from 15 to 70% by volume of the solvent system. In one or more embodiments, the amount of a purified hexane waste solvent may range from a lower limit selected from any one of 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, and 60 vol% to an upper limit selected from any one of 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, and 80 vol% where any lower limit may be paired with any mathematically feasible upper limit.

[0031] One or more embodiments of the present disclosure may be directed to an adhesive composition comprising a solvent system that comprises purified hexane waste in addition to at least one of an aromatic compound, and an oxygenated solvent, or a mixture thereof. In one or more embodiments of the present disclosure, solvent systems for use in thinner and/or surface cleaners may comprise at least one oxygenated compound and at least one aromatic compound.

[0032] The oxygenated solvents of one or more embodiments of the present disclosure are not particularly limited and may include any suitable oxygen- containing solvent such as ketones, esters, ethers, glycols ethers, and alcohols, among others. One or more embodiments may comprise oxygenated solvents such as ethyl acetate, sec-buyl acetate, ethanol and/or alkyl tert-butyl ether. In one or more embodiments, the total amount of the one or more oxygenated solvents may range from a lower limit selected from any one of 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, and 70 vol% to an upper limit selected from any one of 30 vol%, 40 vol%, 50 vol%, 60 vol%, 70 vol%, and 80 vol%, where any lower limit may be paired with any upper limit.

[0033] The aromatic hydrocarbon solvents of one or more embodiments may be monocyclic and may be substituted or unsubstituted. The solvent systems of some embodiments may particularly include alkylbenzenes. In particular embodiments, the solvent system may include one or more of toluene, xylene, and other alkylbenzenes such as mesitylene, ethylbenzene, diethylbenzene, triethylbenzene, cumene, cymene, and the like. In one or more embodiments, the amount of an aromatic compound solvent may range from a lower limit selected from any one of 15 vol%, 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, and 60 vol% to an upper limit selected from any one of 20 vol%, 25 vol%, 30 vol%, 40 vol%, 50 vol%, 60 vol%, and 70 vol%, where any lower limit may be paired with any upper limit.

[0034] Solvent systems for use in adhesive compositions, thinners, and surface cleaners, and methods thereof in accordance with embodiments of the present disclosure may include one or more oxygenated solvents in a total amount of 25 to 80 vol%, and one or more hydrocarbon solvents in a total amount of 15 to 80 vol% wherein at least one of the hydrocarbon solvents is purified hexane waste recycled from polymerization reactions. In some embodiments, the solvent system may comprise two or more hydrocarbon solvents, where at least one is purified hexane waste and at least one is a solvent comprised of an aromatic compound. The hydrocarbon solvents of one or more embodiments are not particularly limited and may include aromatic species, including those discussed above.

[0035] The solute of one or more embodiments is not particularly limited. In some embodiments, the solute may be one or more of a resin or polymer, for example, in applications of the solvent system in adhesive or cleaning applications. In more particular embodiments, the resins may be selected from acrylic resins, nitrocellulose resins, polyester resins, polyol polyester resins, epoxy resins, alkyd resins, melamine resins, maleic resins, phenolic resins, isocyanate-based resins, polychloroprene, polyvinyl chloride, chlorinated polyvinyl chloride, styrene butadiene styrene, styrene butadiene, styrene isoprene styrene and ethylene- vinyl acetate (EVA) and natural rubber.

[0036] On the other hand, as mentioned above, the solvent systems of the present disclosure (incorporating a purified hexane waste) may also find particular use in vegetable oil extraction compositions. Thus, in such embodiments, natural, oil-containing materials may be contacted with a solvent system of the present disclosure, or with purified hexane waste to extract the vegetable oil. Oil containing materials may include, but are not limited to, soybean, cottonseed, rice, peanut, sunflower, com, canola and any other oil-containing crop that may be used as raw material.

[0037] Solvent compositions in accordance with one or more embodiments of the present invention may include one or more additives. The selection of the one or more additives is not particularly limited, and will be highly dependent upon the intended application of the composition. In particular embodiments, the at least one additive may be selected from the group consisting of pigments, dyes, carriers, fillers, and dullness agents. The composition of one or more embodiments may be, for example, a paint composition, a varnish composition, a lacquer composition, an adhesive composition, or a finish composition.

[0038] METHODS AND COMPOSITIONS

[0039] The aforementioned purified hexane waste solvent may be utilized either alone or in combination with another solvent and/or in a solvent system or composition for a wide array of methods and applications, as disclosed above. The uses of solvent systems and compositions in accordance with the present disclosure are not limited to the methods described herein. The solvent systems of one or more embodiments may be used in cleaning compositions, printing inks, varnishes, adhesives, lacquers, thinners or as solvents for oil extraction via solvent extraction methods.

[0040] Adhesives

[0041] Methods in accordance with one or more embodiments of the present disclosure may involve using the aforementioned solvent system compositions to adhere the surfaces of two articles together. In some embodiments, the methods may include applying the solvent system composition to the surface of at least one of the two articles and bringing the two articles into contact with each other. In such adhesive applications, it is envisioned that the solvent system may be designed to have a lower evaporation rate, depending on the type of adhesive, for example, and the desired adhesive strength. That is, in some instances, a lower evaporation rate may be desirable to allow the polymer chains to better intermingle (and adhere together) prior to the evaporation of the solvent system. Particular types of adhesive resins that are envisioned as being used with the solvent system of the present disclosure include from acrylic resins, nitrocellulose resins, polyester resins, polyol polyester resins, epoxy resins, alkyd resins, melamine resins, maleic resins, phenolic resins, isocyanate-based resins, polychloroprene, polyvinyl chloride, chlorinated polyvinyl chloride, styrene butadiene styrene, styrene butadiene, styrene isoprene styrene and ethylene- vinyl acetate (EVA) and natural rubber

[0042] Vegetable Oil Extraction

[0043] Purified hexane waste may also be used to produce vegetable oilseed through solvent extraction processes. Different crops such as soybean, cottonseed, rice, peanut, sunflower, corn, canola and any other crop that may be used as raw material, from which vegetable oil may be extracted. Additionally, the recycled purified hexane waste solvent can be used in the same machinery that the industry already uses without the need of adjustments in operational parameters.

[0044] One or more embodiments of the present disclosure may be directed towards a method of extracting a vegetable oil through solvent extraction from an oil-containing material, where the solvent used in such extraction is a purified hexane waste recycled from olefin polymerization reactions for vegetable oil extraction and/or having the components described herein. Oil containing materials may include, but are not limited to, soybean, cottonseed, rice, peanut, sunflower, corn, canola and any other oil-containing crop that may be used as raw material. The method may include contacting the oil- containing material with a solvent system, prepared in accordance with one or more embodiments of this disclosure, in an amount effective to accomplish the extracting. [0045] Solvent extraction may be accomplished through grinding or flaking of the oil-containing material wherein ground oil-containing material or cake may then be purged or washed with a purified hexane waste which releases the oil in the seed. The oil/solvent blend is next heated to distill off the solvent.

[0046] In one or more embodiments of the present disclosure, additional steps in extracting of vegetable oil may include steps prior to contacting the oilseed material with the solvent system including a dehulling step to remove any hulls, and a size determining step to control the shape and size of particles in the extraction material as they must allow solvent to flow freely, without any great resistance as well as allow for the best potential extraction from each individual particle, by minimizing diffusion pathways. Methods for extracting vegetable oil, in accordance with one or more embodiments of the present disclosure may further include a flaking step to produce flakes of the oil containing material, prior to being brought into contact with the solvent system and a heat treatment step wherein the oil-containing material may be heated to a temperature capable of promoting cell membranes to fracture and break to expose the vegetable oil. In one or more embodiments, the heat treatment step may include heating the oil-containing material to a temperature ranging from any lower limit of 50, 60, 70, and 80° C to any upper limit of 85, 95, 100, 105, and 115° C wherein any lower limit may be combined with any mathematically feasible upper limit.

[0047] The method may further include, feeding the flakes of the oil-containing material into an extractor and subsequently contacted by a purified hexane waste comprising solvent system to produce a miscella solution comprising the purified hexane waste solvent and the extracted vegetable oil. In one or more embodiments the miscella solution may then be treated by distillation to separate the solvent from the extracted oil.

[0048] In one or more embodiments, the flakes of the oil-containing material may be treated with a solvent system in a stationary bed extraction, or in a counter flow process. In certain embodiments, the flakes of the oil-containing material may be treated with the solvent system in a ratio of solvents to solids that includes any of 1:1, 2:1, 3:1, 5:1 to 8:1, 9:1, 10:1 and any ratio ranging in between the upper and lower bounds provided therein. In one or more embodiments, the method may further include treating the flakes of oil- containing material with the solvent system at a temperature ranging from any lower limit of 30, 40, 50, and 60° C to any upper limit of 70, 80, 90, and 100° C wherein any lower limit may be combined with any mathematically feasible upper limit.

[0049] Thinners and Surface Cleaners

[0050] In one or more embodiments, purified hexane waste solvent systems in accordance with the present disclosure may be used in a method of thinning a first composition, the method including adding any of the aforementioned solvent systems to the first composition. The identity of the first composition is not particularly limited, but may be a one or more of an alkyl resin, a nitrocellulose resin, or a polyurethane, for example.

[0051] A solvent comprising purified hexane waste in accordance with one or more embodiments of the present disclosure may be used in formulations as a diluent and also for cleaning purposes. A wide range of resins, such as alkyl resins including those of long, short and medium length chains, nitrocellulose- based resins and polyurethane resins may be diluted with the purified hexane waste. In the case of cleaning, the function of the thinner may be to remove wasted paints from the system (such as industrial systems) and also to degrease and/or pre-treat surfaces or substrates to receive a coating.

[0052] In one or more embodiments, purified hexane waste in accordance with the present disclosure may be used in a method, or in solvent system as disclosed herein to be used in a method of cleaning a surface of an article. In some embodiments, the method may include contacting the surface of the article with the purified hexane waste or purified hexane waste comprising solvent system. The amount of solvent system used is not particularly limited but will generally be an amount effective to accomplish cleaning. The cleaning may generate a composition that includes the solvent system and the components that were removed from the surface of the article. In one or more embodiments a solvent system comprising purified hexane waste and an oxygenated compound may be used to contact the surface of the article to be cleaned.

[0053] EXAMPLES

[0054] Examples formulations 1-4 are formulations for solvent systems of an adhesive composition comprising purified hexane waste recycled from hexane used in an olefin production polymerization process. The table below comprises formulations developed, and the vol% for each component. The purified hexane waste can also be used in toluene-free adhesives, as can be seen in the table below (Examples 2, 3, 4). The recycled solvent can be used in the same machinery that the industry already uses without the need of adjustments in operational parameters.

[0055] Example 2

[0056] As disclosed above, another way to improve sustainability is the conversion of waste products into raw material for future application in other processes. To evaluate the effect of the circular economy of the purified hexane waste, a life cycle assessment can be performed to measure impacts (including CO2 emissions) of current and new products. A life-cycle- assessment was conducted and is provided in Fig. 1 to compare the environmental performance across various categories of the presently disclosed recycled hexane with the traditional hexane that is used in the applications described above. As demonstrated in Fig. 1, it is possible to observe that the recycled hexane has a positive environmental impact in almost all of the categories measured in Fig. 1.

[0057] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.

Claims

1. A purified hexane waste, comprising: n-hexane in an amount ranging from 55 to 75% by mass; one or more isomers of hexane in an amount ranging from 5 to 40% by mass; one or more metals selected from the group consisting of Al, Ca, Mg, Ti, or a mixture thereof; water in an amount that is less than 300 ppm; monochloroethane in an amount of less than 1.5%; ethanol in an amount of less than 1000 ppm; and optionally, one or more additional secondary impurities selected from the group consisting of non-C6 alkanes, non-C6 alkenes.

2. The purified hexane waste of claim 1, wherein the one or more isomers of hexane are selected from the group consisting of 3-methylpentane, methylcyclopentane, 2-methylpentane, cyclohexane, 2,3-dimethylbutane and 2,2-dimethylbutane or a mixture thereof.

3. The purified hexane waste of any of the above claims, wherein in addition to ethanol and monochloroethane the purified hexane waste comprises one or more additional secondary impurities selected from the group consisting of n- octane, n-butane, 3-methylheptane, or a mixture thereof.

4. The purified hexane waste of any of the above claims, wherein the purified hexane waste comprises one or more secondary impurities in a total amount ranging from 0.01 to 3% by mass.

5. An adhesive composition, comprising: at least one resin; and a solvent system comprising a purified hexane waste of any of the above claims.

6. An adhesive composition, comprising: at least one resin; and a solvent system comprising a purified hexane waste recycled from olefin polymerization reactions.

7. The adhesive composition of claim 5 or 6, wherein the purified hexane waste is present in the solvent system in amount ranging from 20 to 60% by volume.

8. The composition of any of the above claims, wherein the solvent system further comprises: at least one oxygenated solvent.

9. The composition of any of claims 1-3, wherein the at least one resin is selected from the group consisting of acrylic resins, nitrocellulose resins, polyester resins, polyol polyester resins, epoxy resins, alkyd resins, melamine resins, maleic resins, phenolic resins, isocyanate-based resins, polychloroprene, polyvinyl chloride, chlorinated polyvinyl chloride, styrene butadiene styrene, styrene butadiene, styrene isoprene styrene, and ethylene vinyl acetate and natural rubber

10. A method of adhering two articles together, comprising: applying the composition of any of claims 5 to 9 to at least one of the two articles; and bringing the two articles into contact with each other, thereby adhering the two articles together.

11. A method of extracting vegetable oil by solvent extraction from an oil- containing material, comprising: contacting the oil-containing material with a solvent system in an amount effective to accomplish the extracting, wherein the solvent system comprises the purified hexane waste of any of claims 1 to 4.

12. A method of extracting vegetable oil by solvent extraction from an oil- containing material, comprising: contacting the oil-containing material with a solvent system in an amount effective to accomplish the extracting, wherein the solvent system comprises a purified hexane waste recycled from olefin polymerization reactions.

13. The method of claim 11 or 12, further comprising: subjecting the oil-containing material to: a dehulling step to remove hulls a size determining step; a flaking step to produce flakes of the oil-containing material, prior to being brought into contact with the solvent system; and a heat treatment step wherein the oil-containing material is heated to about 70- 105°C degrees to promote cell membranes break and expose the oil.

14. The method of any claim 13, wherein the flakes of the oil-containing material is fed into an extractor and contacted by the solvent system produce a miscella solution comprising the purified hexane waste and an extracted oil

15. The method of claim 14, wherein the miscella solution is treated by distillation to separate the solvent from the extracted oil.

16. The method of any of claims 13 to 15, wherein the flakes of the oil-containing material are treated with the solvent system in a stationary bed extraction.

17. The method of claim any of claims 13 to 15, wherein the flakes of the oil- containing material are treated with the solvent system in a counter flow process.

18. The method of any of claims 13 to 17, wherein the flakes of the oil-containing material are treated with the solvent system in a 2:1 to 8:1 ratio of solvent to solids.

19. The method of any of claims 13 to 18, wherein the flakes of the oil-containing material are treated with the solvent system at a temperature between 50 and 80° C.

20. Use of the purified hexane waste of any of claims 1 to 4 in an adhesive composition or vegetable oil extraction.

21. Use of a purified hexane waste recycled from olefin polymerization reactions in an adhesive composition or vegetable oil extraction.

22. A solvent system comprising the purified hexane waste in any of claims 1 to 4 and at least one oxygenated compound.

23. The solvent system of claim 22, further comprising: at least one aromatic compound.

24. A method of cleaning a surface of an article, comprising: contacting the surface of the article with the solvent system of any of claims 22-23 in an amount effective to accomplish cleaning.