[0001] The present disclosure relates to a method and apparatus for removing oxygen from a chemical.

BACKGROUND

[0002] Many commonly used chemicals, including many inorganic chemicals, and many organic chemicals form peroxides when in the presence of oxygen gas (0 ₂ ). (Donald E. Clark, "Peroxides and peroxide-forming compounds, Chemical Health and Safety, September / October 2001 12-22.) Peroxides have the eneral structures shown below:

_^ . , Hydroperoxide

Peroxide

[0003] The R 1 and R 2 groups of peroxide can potentially be many different chemical atoms or groups, inorganic or organic. If the R 1 and R 2 groups are organic groups, then the peroxide is an organic peroxide. To form a hydroperoxide, the R group is hydrogen. To form an organic hydroperoxide, the R 1 is organic and R 2 is hydrogen.

[0004] It is well known in the art that many organic compounds comprising activated C-H bonds can slowly react with oxygen gas (0 ₂ is a relatively stable but still reactive free radical), often during shipping or extended storage, to form organic peroxides and hydroperoxides.

[0005] It is also known in the art that the 0-0 bond of peroxides and hydroperoxides easily break to form free radicals having the structure RO or HO , and these alkoxy or hydroxyl radicals can react with and/or oxidize many other chemicals, to form undesirable or dangerous contaminants. Peroxides can also sometimes initiate self- polymerization (either slow or explosively fast) of many polymerizable organic compounds with unsaturated chemical bonds. Such side product formation and/or self-polymerizations are normally undesirable during transport and/or storage, and can lead to hazardous conditions which may result in explosion and fire.

[0006] While various chemical additives are known that reduce peroxide or hydroperoxide formation, or scavenge peroxides or hydroperoxides after they are formed, and thereby decrease the accompanying hazards, such additives are often otherwise undesirable contaminants to the bulk chemical, and may require removal prior to the use of the chemical, such as for example in polymerizations or co-polymerizations.

[0007] Thus, there is a need for a practical and economical means to reduce the rate of undesirable peroxide formation in chemicals in storage containers or undergoing transport. SUMMARY OF THE INVENTION

[0008] In one aspect the present invention relates to a method for removing oxygen from a chemical; comprising:

(1) purging a vessel containing a chemical with an inert gas;

(2) circulating the chemical or the inert gas, or a mixture thereof, from the vessel through a recirculation loop apparatus that performs the steps comprising: i. monitoring the oxygen level; and

ii. scavenging the oxygen; and

(3) transporting the chemical or the inert gas from the vessel through the recirculation loop apparatus until an acceptable oxygen level has been reached;

wherein the method does not comprise substantially any of an additive for scavenging a peroxide or for preventing peroxide formation.

[0009] An additional related aspect of the invention described herein relates to an apparatus for removing oxygen from a chemical; comprising:

(1) a vessel,

wherein the vessel is used to contain a chemical;

wherein the vessel has one or more inlets and one or more outlets for an inert gas; and

(2) a recirculation loop apparatus to and from the vessel,

wherein the recirculation loop apparatus comprises:

i. a pump, wherein the pump transports the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation apparatus; ii. a monitoring device, wherein the monitoring device measures the

oxygen level; and

iii. an oxygen scavenger.

[0010] Additional advantages will be set forth in part in the description and drawings which follow, and in part will be obvious from the description, or may be learned by practice of the aspects described below. The advantages described below will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to be restrictive of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawing, which is incorporated in and constitutes a part of this specification, illustrates several aspects described below. Like numbers represent the same elements throughout the figures.

[0012] FIG. 1 shows a schematic diagram of one aspect of an apparatus constructed in accordance with the teachings of the present invention.

DETAILED DESCRIPTION

[0013] Before the present compounds, compositions, apparatuses, devices, and/or methods are disclosed and described in this detailed description, it is to be understood that the aspects described in the description below are not intended to be limited to specific materials or specific apparatuses, or devices described herein, which as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting on the claims.

[0014] Disclosed are materials, compounds, compositions, and components that can be used for, can be used in conjunction with, can be used in preparation for, or are products of the disclosed methods and apparatuses. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these apparatuses may not be explicitly disclosed, each is specifically contemplated and described herein. Thus, if there are a variety of additional components that can be incorporated into the apparatus, it is understood that each of these additional components can be used with any specific embodiment or combination of embodiments of the disclosed methods, and that each such combination is specifically contemplated and should be considered disclosed.

[0015] Nomenclature for compounds, including organic compounds, can be given using common names, International Union of Pure and Applied Chemistry (IUPAC), or Chemical Abstracts (CAS) recommendations for nomenclature.

A. DEFINITIONS

[0016] In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined to have the following meanings:

[0017] It must be noted that, as used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise.

[0018] "Optional" or "optionally" means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0019] Ranges may be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. In some particular aspects of the inventions described herein and the terminology used to describe them herein, the word "about" can mean a variation of + 10% of the value specified in the range.

[0020] Variables such as ppm, temperature and pressure used throughout the application are the same variables as previously defined unless stated to the contrary.

[0021] The term "chemical" as used herein is any chemical that can be stored, transported, or used for its intended purpose.

[0022] The term "vessel" can be any vessel suitable for the transport and/or storage of a chemical.

[0023] The term "peroxide-forming compound" is intended to refer to a compound that by its intrinsic chemical nature has the tendency to form a peroxide when exposed to oxygen gas for any period of time.

[0024] It should be understood that a reference to "peroxides" herein is intended to also include a reference to the sub-genus of "hydroperoxides," unless clearly indicated to the contrary.

[0025] The term "oxygen scavenger" relates to any device that is designed for scavenging oxygen molecules from a gas or liquid, including a device that comprises a chemical agent that can remove or scavenge oxygen molecules from a gas or liquid by contact, and/or chemical reaction, or by any other suitable means.

[0026] The term "monitoring device" is any analytical device capable of detecting the level of oxygen (0 ₂ ) and/or water in a sample of the substance being monitored.

[0027] The term "Acceptable oxygen level" as used herein is a concentration of oxygen (0 ₂ ) gas dissolved in a chemical or mixture of chemicals, or in the inert gas in contact with a chemical or mixture of chemicals, that in the judgment of the producers or sellers of the chemical and/or their customers suitably slows or prevents the formation of peroxides in the chemical or mixture of chemicals.

[0028] The term "inert gas" is a gas or mixture of gases which are inert to chemical reactivity with air, water, the compounds being stored or transported, or other substances likely to be encountered during shipment and storage of the chemicals.

[0029] The term "chemical additive" refers to a chemical compound which is added to another chemical compound to improve or preserve the chemical and physical properties of the compound to which it is added.

B . METHOD FOR REMOVING OXYGEN FROM A CHEMICAL

[0030] One aspect of the present invention relates to a method for removing oxygen from a chemical; comprising:

(1) purging a vessel containing a chemical with an inert gas;

(2) circulating the chemical or the inert gas, or a mixture thereof, from the vessel through a recirculation loop apparatus that performs the steps comprising: i. monitoring the oxygen level; and

ii. scavenging the oxygen; and

(3) transporting the chemical or the inert gas, or a mixture thereof from the vessel through the recirculation loop apparatus until an acceptable oxygen level has been reached;

wherein the method does not comprise substantially any of an additive for scavenging a peroxide or preventing peroxide formation.

[0031] Reducing the oxygen level during storage and/or transport reduces the formation of peroxides and/or hydroperoxides. However, in a large chemical storage container, reducing the oxygen level can be expensive and difficult to achieve and maintain, and often impractical on a large scale. With the method and/or apparatus of the present invention, practical and inexpensive reduction of the oxygen level is achieved.

[0032] Many aspects of the methods described and/or claimed herein relate to removing oxygen (0 ₂ ) or water from a chemical. There can be many potential purposes for removing oxygen or water from a chemical, depending on the end uses of the chemical. The various methods described and claimed herein can be employed for achieving any valid purpose for removing oxygen or water from a chemical. For example, removing oxygen or water from a chemical may reduce a chemical's tendency to decompose oxygen or water sensitive materials that that the chemical may be mixed with for various potential

downstream applications.

[0033] In one aspect, the chemical can be solid, liquid or gas. In a further aspect, the chemical can be a gas or a vapor. In another aspect, the chemical can be an organic, an inorganic, or an organometallic compound. In yet another aspect, the chemical is an organic liquid. In an even further aspect, the chemical comprises an olefin, a diene or an ether. In one aspect, the chemical is an olefin.

[0034] In one aspect, the chemical is ethylene. In another aspect, the chemical is a diene. In a further aspect, the chemical is butadiene or cyclopentadience. In an even further aspect, the chemical comprises an ether. In a yet further aspect, the chemical comprises tetrahydrofuran (THF), diethyl ether, or methyl tertiary-butyl ether (MTBE), or a mixture thereof.

[0035] In a further aspect, the chemical comprises dialkyl ethers of ethylene glycol, diethylene glycol, or triethylene glycol, or a mixture thereof. In another aspect, the chemical comprises an aromatic or a hetero aromatic, or a mixture thereof. In one aspect, the chemical comprises pyridine, benzene, toluene, styrene, acrylate, or cyanoacrylate.

[0036] In some aspects of the methods of the invention, the chemical is part of a subgenus of chemicals that are known in the art as being susceptible to the formation of peroxides.

[0037] In one aspect, the chemical forms at least one peroxide in the presence of oxygen. Such substances often contain carbon-hydrogen bonds that neighbor other functional groups, which "activate" those carbon-hydrogen bonds toward attack by either free radicals, such as for example oxygen (0 ₂ ) gas, which is a relatively stable free radical. Such substances often contain electron rich moieties such as an unsaturated bond, (a double or triple bond) found in alkene (olefin) and alkyne, and C-0 bond found in ether or carboxylic acid. Well known peroxide forming compounds include an olefin such as styrene, butadiene, ethylene and the like; and ether such as tetrahydrofuran (THF), diethyl ether, methyl tertiary- butyl ether (MTBE), and the like. A list of some common peroxide-forming compounds can be found in D.E. Clark, Chemical Health & Safety, October 2001, page 18, Table 1; and Rep#07-207, Information on peroxide-forming compounds, Stanford University, July 23, 2008, which are incorporated herein by reference for their teaching of peroxide-forming compounds.

[0038] It should be understood that a reference to "peroxides" herein is intended to also include a reference to the sub-genus of "hydroperoxides," unless clearly indicated to the contrary.

[0039] Many aspects of the methods described herein relate to and can be applied to removing oxygen from a chemical in order to prevent the chemical from forming at least one peroxide in the presence of oxygen during storage and/or transport of the chemical. Many factors can be involved in determining whether or not a given chemical will or will not form peroxides readily enough to justify the use of the methods and apparatuses described herein. Those of ordinary skill in the relevant arts will be aware of the specific chemical and physical properties of a specific chemical they desire to store and transport, the intended length and conditions of storage, and intended customer applications, economic factors, and any other factors needed to determine empirically whether the methods and apparatuses described herein can or should be applied to slow or prevent the formation of peroxides in a particular chemical of interest to that person.

[0040] In one aspect, the oxygen is removed by purging a vessel containing a chemical with an inert gas. Once closed to external atmospheric water and air, the vessel and/or recirculation loop apparatus are typically purged with the inert gases. One or more inlets and outlets for the inert gas are attached to the vessel in one or more suitable locations. If the chemical to be stored and purged is a liquid, the inlet for the inert gas can be placed either above or below the surface of the liquid chemical. Purging employs the inert gases to physically sweep oxygen or water from the vessel and/or chemical contents. Often purging of the vessel occurs after solid or liquid chemicals have been added to the vessel, so as to simultaneously sweep oxygen and/or air from both the vessel or entrained or dissolved in the chemical. Purging can occur before, after, or during the filling of the vessel with the solid, liquid, or gaseous chemical to be stored, and may continue during storage or transport.

[0041] In another aspect, the vessel can be suitable for the transport and/or storage of a chemical. In a further aspect, the vessel can be a railroad tank car, a steel drum, a plastic drum, a tanker truck trailer, an Intermediate Bulk Container (IBC), a semi-permanent storage tank, or a permanent storage tank. A vessel designed for the transport of flammable and reactive organic chemicals can be employed in many aspects of the inventions, and those which are opaque to UV/visible light can be employed in many aspects of the inventions. Such vessels can be fitted with boundary walls and inlet and outlet ports or devices that can be closed, so the vessel can be "closed" so as to substantially exclude penetration of atmospheric gases or water.

[0042] Among the steps employed in the method described herein includes the step of "purging a vessel for a chemical with an inert gas." The vessel employed in such methods can employ many sizes, shapes, number, kind, placement of openings, and materials of construction for the vessels. In one aspect, the vessel can be designed so as to enable "closure" of the vessel so as to enable exclusion of undesired contamination by external materials, for example, oxygen, air, or water, or a mixture thereof. The vessel walls can be constructed from material commonly used in the art that is capable of effectively containing the chemical, while simultaneously excluding oxygen, water, or air. Examples of materials suitable for constructing the vessel include a metal (such as carbon or stainless steel, or corrosion resistant alloy, or a mixture thereof), ceramic, glass, plastic or coating of insoluble organic polymer, or a combination thereof. The vessel contains sealable openings for inlet, outlet, or circulation of the inert gases and/or the chemicals to be stored.

[0043] In one aspect, the inert gas is a gas or a mixture of gases which are inert to chemical reactivity with air, water, the compounds being stored or transported, or other substances likely to be encountered during shipment and storage of the chemicals. Non- limiting examples of inert gases include inflammable gases such as nitrogen, argon, helium and the like. In some aspects of the inventions described herein, the inert gas comprises nitrogen or argon, or a mixture thereof. In some aspects of the inventions described herein, the inert gases may contain small amounts of vapors from the gaseous or liquid chemicals being stored, but the presence of small amounts of vapors of the chemicals being stored does not necessarily exclude the mixed inert gases and vapors from being described as "inert."

[0044] In one aspect, the method comprises circulating the chemical or the inert gas, or a mixture thereof, from the vessel through a recirculation loop apparatus. In a further aspect, the chemical remains in the vessel, while the inert gas is circulated through a recirculation loop apparatus. In another aspect, the chemical is circulated through a recirculation loop apparatus. In a further aspect, the chemical and the inert gas are both circulated through the recirculation loop apparatus. In one aspect, when the chemical is circulated through the loop, the chemical is a gas. In another aspect, when the chemical is a gas, the chemical and/or the inert gas can be circulated through the recirculation loop apparatus. [0045] In one aspect, the circulation time will be monitored by the monitoring device. Once the monitoring device shows acceptable levels, then the circulation can be terminated.

[0046] In one aspect, the method comprises a recirculation loop apparatus that comprises monitoring the oxygen level and scavenging the oxygen.

[0047] In one aspect, the monitoring occurs by using a monitoring device. In one aspect the monitoring device is any analytical device capable of detecting the level of oxygen (0 ₂ ) and/or water in a sample of the substance being monitored. In another aspect, the device can be capable of measuring the oxygen concentration. In a further aspect, the device can also be capable of measuring the water concentration.

[0048] In one aspect, a single monitoring device can measure both oxygen

concentration and water concentration. In another aspect, two monitoring devices can be used with one device to measure oxygen concentration and another device to measure water concentration.

[0049] Many oxygen monitoring devices are commercially available; for example, the optical sensor FDO™ 700 IQ supplied by WTW Inc., PO Box 9010,151 Graham Road College Station, Texas 77842, or the InPro6950i G from Mettler-Toledo Inc., 1900 Polaris Parkway, Columbus OH 43240. The oxygen monitoring device can have as few fittings, parts and connectors as possible. In one aspect, the oxygen monitoring device can comprise one overall device.

[0050] In one aspect, the monitoring the oxygen level precedes the scavenging of the oxygen. In another aspect, the scavenging the oxygen precedes the monitoring of the oxygen level.

[0051] In a further aspect, the scavenging the oxygen occurs using an oxygen scavenger. In one aspect, the oxygen scavenger relates to any device that is designed for scavenging oxygen molecules from a gas or liquid. In another aspect, the oxygen scavenger can include a device that comprises a chemical agent that can remove or scavenge oxygen molecules from a gas or liquid by contact, and/or chemical reaction, or by any other suitable means.

[0052] In some aspects of the inventions, the oxygen scavenging comprises an activated metal that can react rapidly and directly with oxygen. In another aspect, the oxygen scavenging comprises an activated metal that can react rapidly and directly with oxygen at high temperatures. In one aspect, the activated metal can comprise finely divided or dispersed copper or iron. In a further aspect, the activated metal can comprise oxides of copper or iron. The finely divided spent copper oxide scavenger can be reactivated by treatment of the dispersed copper oxide with hydrogen/copper mixtures at elevated temperature. Other examples of suitable oxygen scavengers can include columns or cartridges that contain organic compounds that can function as reducing agents for oxygen. In one aspect, the organic compound can comprise a bis-hydroxy aromatic. In another aspect, the organic compound can comprise hydroquinone, catechol, or substituted variations of such bisphenols, or a mixture thereof. Such bisphenols / hydroquinones can easily give up electrons and/or hydrogen atoms, in order to reduce other compounds, including oxygen, and thereby become oxidized to form benzoquinones or napthoquinones.

1,4-benzoquinone

hydroquinone

catechol

1 ,2-benzoquinone

[0053] The electrons and hydrogen ions can be furnished by organic reducing agents. In one aspect, the organic reducing agent can be hydroquinone and similar di- hydroxyaromatic that can reduce 0 ₂ to H ₂ 0, and thereby serve as oxygen scavengers, which can potentially be regenerated by treatment with reducing agents and sources of hydrogen ions.

[0054] The oxygen scavengers can also optionally comprise a variety of agents for removing water or water vapor from the chemicals, regardless of whether the water was present in the chemical when it was synthesized, or was formed by the oxygen scavenger by reduction of oxygen to form water.

[0055] Oxygen scavengers can also comprise a transition metal such as copper, iron, or iron salts, for example, those disclosed in US 8,226,850, hereby incorporated herein by reference for its teaching of oxygen scavengers. Oxygen scavengers can also comprise noble metal catalysts, bisulfites, dithionites, hydrazines, guanidines, semicarbazides,

hydroxylamines, oximes, or activated aldehydes and others as described in Malcolm A. Kelland, Production Chemicals for the Oil and Gas Industry Chap 16, Oxygen Scavengers, CRC Press 2009, hereby incorporated herein by reference for its teaching regarding the identities and uses of oxygen scavenging agents.

[0056] The oxygen scavenging agents can optionally be dispersed on supports that can be constructed from various suitable materials such as high surface area objects made from metals, inorganic oxides or suitable organic polymers. The device can be designed so that the components of the column or cartridge are replaceable, can be removed after use, and can optionally be renewed and recharged by chemical means.

[0057] In one aspect, the method comprises transporting the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation loop apparatus.

[0058] In many aspects of the methods described and/or claimed herein, the chemical or the inert gas, or a mixture thereof, are transported, circulated, or re-circulated from the vessel and though the loop, and back into the vessel, after at least some scavenging of oxygen and/or water has been achieved, or until an acceptable oxygen level has been reached in the chemicals in the vessel. As discussed above, selection of acceptable oxygen levels in a particular chemical of interest requires consideration of many factors, and is ordinarily selected in the context of one chemical of interest to the manufacturer or consumer of the chemical.

[0059] In many aspects of the methods described and/or claimed herein, one or more chemicals or mixtures of chemicals can be contained in the vessel and/or recirculated through the recirculation loop apparatus. Those chemicals can be gases or mixtures of gases or vapors, or can be liquids or mixtures of liquid, or can be solids or mixtures of solids. In some aspects of the methods, the chemical is a gas or vapor, such as, for example, ethylene above its normal boiling point of -103.7 °C. In many aspects of the methods, the chemical is a liquid, such as for example ethylene below its normal boiling point of -103.7 °C. Similarly, butadiene, with a normal boiling point of -4.4 °C, can recirculated and/or oxygen scavenged as either a gas or liquid. In some aspects of the invention, the chemical can be a solid in contact with its own liquid or vapor, as well as in contact with the inert gas. In many aspects of the methods, the chemical is an organic liquid. In some aspects of the methods, the chemical is a solid.

[0060] In one aspect, the method comprises transporting the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation loop apparatus until an acceptable oxygen level has been reached. [0061] In one aspect, the acceptable oxygen level is a concentration of oxygen (0 ₂ ) gas dissolved in a chemical or mixture of chemicals, or in the inert gas in contact with a chemical or mixture of chemicals, that in the judgment of the producers or sellers of the chemical and/or their customers suitably slows or prevents the formation of peroxides in the chemical or mixture of chemicals. Many factors must be considered in order to choose an acceptable oxygen level for a chemical of interest. An acceptable oxygen level can be empirically determined or chosen by one of ordinary skill in the art using known technical and analytical methods, for each individual chemical or mixture of chemicals to be stored, depending upon their individual chemical and physical properties, and likely anticipated conditions and length of storage. In some cases, a suitable oxygen level can be dictated by customer requirements as a specification. For example, in some aspects and for some chemicals, acceptable oxygen levels in the range of about 1 part per million (ppm) to about 1 mole % can be suitable and desirable. In other aspects and chemicals, acceptable oxygen levels can often be in the range of from about 1 ppm to about 200 ppm, including exemplary values of 5 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 110 ppm, 120 ppm, 130 ppm, 140 ppm, 150 ppm, 160 ppm, 170 ppm, 180 ppm, and 190 ppm. For example, the acceptable oxygen level can be in the range of from 1 ppm to 10 ppm. In some aspects of the inventions, acceptable oxygen levels can be below about 10 ppm, or below about 5 ppm, or below about 1 ppm.

[0062] In one aspect, the method does not comprise substantially any of an additive for scavenging a peroxide or for preventing peroxide formation. In a further aspect, the method does not comprise any of an additive for scavenging a peroxide or for preventing peroxide formation. In a further aspect, the method does not comprise an additive for scavenging a peroxide or for preventing peroxide formation because the oxygen has been removed, preventing peroxide formation. As such, an additive for scavenging a peroxide or for preventing peroxide formation does not need to be added to the method.

[0063] In a further aspect, the term additive refers to a chemical additive. In a further aspect, the term additive refers to anything directly added that decomposes or prevents peroxides from forming. The chemical additive does not include preventing peroxide formation by removing the oxygen. In contrast, the present invention prevents peroxide formation by removing the oxygen.

[0064] In another aspect, the chemical additive comprises a chemical compound. In a further aspect, the chemical additive is a chemical compound that can be added to the chemical. In a yet further aspect, the chemical additive is present in the chemical in an amount generally less than about 5 weight percent (wt%), to improve or preserve the chemical and physical properties of the compound to which it is added. Improvements include greater stability towards air oxidation, inhibition of undesired polymerization or other undesired side reactions, the scavenging and decomposing peroxides that can form, and the like. Many additives are known which scavenge peroxides and/or hydroperoxides once they have formed, and such additives are often bases and/or reducing agents, which can deprotonate and/or reduce hydroperoxides, or scavenge free radicals that form from the self- decomposition of peroxides. Sterically hindered phenols, such a butylated hydroxytoluene (BHT), are well known as anti-oxidant additive that added to many air-oxidizable chemical products.

[0065] In one aspect, when the method does not comprise substantially any of an additive for scavenging a peroxide or preventing peroxide formation, the method can comprise an additive in an amount ranging from 0 wt % to 1 wt %, including exemplary values of 0.001 wt%, 0.01 wt%, 0.1 wt %, 0.15 wt %, 0.20 wt %, 0.25 wt %, 0.30 wt %, 0.35 wt %, 0.40 wt %, 0.45 wt %, 0.5 wt %, 0.55 wt %, 0.6 wt %, 0.65 wt %, 0.7 wt %, 0.75 wt %, 0.8 wt %, 0.85 wt %, 0.9 wt %, and 0.95 wt %. In further aspects, the range can be derived from any two exemplary values. For example, when the method does not comprise substantially any of an additive for scavenging a peroxide or preventing peroxide formation, the method can comprise an additive in an amount ranging from 0 wt % to 0.5 wt %.

[0066] In some aspects of the methods and/or apparatuses described and/or claimed herein, the apparatus does not comprise, or the method or chemical does not comprise use of an additive for scavenging peroxides from the chemicals or preventing the formation of peroxides, including hydroperoxides. Such additives can be added in small amounts to many chemicals, but can be undesirable to down-stream users and customers, and must sometimes be removed from the chemicals prior to their end use. Use of the methods and apparatuses described herein can however avoid the need for the use of such additives, and the associated purity issues or downstream use issues, and thus unexpectedly solves a long-standing problem in the art.

[0067] The methods disclosed herein can utilize the apparatuses disclosed herein. C. APPARATUS FOR REMOVING OXYGEN FROM A CHEMICAL

[0068] Many related aspects of the inventions described herein relate to an apparatus for removing oxygen from a chemical; comprising: (1) a vessel,

wherein the vessel is used to contain a chemical;

wherein the vessel has one or more inlets and one or more outlets for an inert gas; and

(2) a recirculation loop apparatus to and from the vessel,

wherein the recirculation loop apparatus comprises:

i. a pump, wherein the pump transports the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation apparatus; ii. a monitoring device, wherein the monitoring device measures the oxygen level; and

iii. an oxygen scavenger.

[0069] Many aspects of the apparatuses described and/or claimed herein relate to removing oxygen (0 ₂ ) or water from a chemical. There can be many potential purposes for removing oxygen or water from a chemical, depending on the end uses of the chemical. The various apparatuses described and claimed herein can be employed for achieving any valid purpose for removing oxygen or water from a chemical. For example, removing oxygen or water from a chemical may reduce a chemical's tendency to decompose oxygen or water sensitive materials that that the chemical may be mixed with for various potential downstream applications.

[0070] In one aspect, the chemical can be solid, liquid or gas. In a further aspect, the chemical can be a gas or a vapor. In another aspect, the chemical can be an organic, an inorganic, and an organometallic compound. In yet another aspect, the chemical is an organic liquid. In an even further aspect, the chemical comprises an olefin, a diene or an ether. In one aspect, the chemical is an olefin.

[0071] In one aspect, the chemical is ethylene. In another aspect, the chemical is a diene. In a further aspect, the chemical is butadiene or cyclopentadience. In an even further aspect, the chemical comprises an ether. In a yet further aspect, the chemical comprises tetrahydrofuran (THF), diethyl ether, or methyl tertiary-butyl ether (MTBE), or a mixture thereof.

[0072] In a further aspect, the chemical comprises dialkyl ethers of ethylene glycol, diethylene glycol, or triethylene glycol, or a mixture thereof. In another aspect, the chemical comprises an aromatic or a hetero aromatic, or a mixture thereof. In one aspect, the chemical comprises pyridine, benzene, toluene, styrene, acrylate, or cyanoacrylate. [0073] In some aspects of the apparatuses of the invention, the chemical is part of a sub-genus of chemicals that are known in the art as being susceptible to the formation of peroxides.

[0074] In one aspect, the chemical forms at least one peroxide in the presence of oxygen. Such substances often contain carbon-hydrogen bonds that neighbor other functional groups, which "activate" those carbon-hydrogen bonds toward attack by either free radicals, such as for example oxygen (02) gas, which is a relatively stable free radical. Such substances often contain electron rich moieties such as an unsaturated bond, (a double or triple bond) found in alkene (olefin) and alkyne, and C-0 bond found in ether or carboxylic acid. Well known peroxide forming compounds include an olefin such as styrene, butadiene, ethylene and the like; and ether such as tetrahydrofuran (THF), diethyl ether, methyl tertiary- butyl ether (MTBE), and the like. A list of some common peroxide-forming compounds can be found in D.E. Clark, Chemical Health & Safety, October 2001, page 18, Table 1; and Rep#07-207, Information on peroxide-forming compounds, Stanford University, July 23, 2008, which are incorporated herein by reference for their disclosure of peroxide-forming compounds.

[0075] In one aspect, the vessel is used to contain a chemical. In another aspect, the vessel can be suitable for the transport and/or storage of a chemical. In a further aspect, the vessel can be a railroad tank car, a steel drum, a plastic drum, a tanker truck trailer, an Intermediate Bulk Container (IBC), a semi-permanent storage tank, or a permanent storage tank. A vessel designed for the transport of flammable and reactive organic chemicals can be employed in many aspects of the inventions, and those which are opaque to UV/visible light can be employed in many aspects of the inventions. Such vessels can be fitted with boundary walls and inlet and outlet ports or devices that can be closed, so the vessel can be "closed" so as to substantially exclude penetration of atmospheric gases or water. In one aspect, the vessel comprises a railroad tank car, a tanker trailer, a drum, an intermediate bulk container (IBC), or a storage container.

[0076] In a further aspect, the vessel has one or more inlets and one or more outlets for an inert gas. One or more inlets and outlets for the inert gas can be attached to the vessel in one or more suitable locations. If the chemical to be stored and purged is a liquid, the inlet for the inert gas can be placed either above or below the surface of the liquid chemical.

Purging employs the inert gases to physically sweep oxygen or water from the vessel and/or chemical contents. Often purging of the vessel occurs after solid or liquid chemicals have been added to the vessel, so as to simultaneously sweep oxygen and/or air from both the vessel or entrained or dissolved in the chemical. Purging can occur before, after, or during the filling of the vessel with the solid, liquid, or gaseous chemical to be stored, and may continue during storage or transport.

[0077] In one aspect, the apparatus comprises a recirculation loop apparatus to and from the vessel. A recirculation loop apparatus is attached to at least one inlet and at least one outlet of the vessel, so as to allow recirculation and/or transport of either the chemical, or the inert gas, or a mixture of both the chemical and inert gas, out of the bulk space of the vessel, through the recirculation loop apparatus, and back into the bulk space of the vessel. One or more inlets and outlets for the recirculation loop device can be placed in one or more configurations either below or above the fill level of solid or liquid chemicals to be stored in the container, so as to enable recirculation of the chemicals, the inert gases, or mixtures of both. The combination of the vessel and recirculation loop apparatus can be considered to form a "closed" loop, in the sense that it enables recirculation of the chemical and/or gases within the loop formed by the combination of the vessel and the recirculation loop apparatus.

[0078] The recirculation loop apparatus can be designed and constructed in many ways, either as integrated devices or as separate component devices within the recirculation loop apparatus connected by smaller vessels, pipes, or other devices. The recirculation loop device can be mounted internally to the vessel, and/or external to the vessel. It should be noted that temperatures and pressures inside the recirculation loop device can be different in the recirculation loop device than they are in the vessel, and can be controlled so as to better optimize oxygen scavenging activity inside the recirculation loop device than might be obtainable under the conditions inside the vessel. In one aspect, the temperature of the apparatus is ambient temperature. In a further aspect, the temperature of the apparatus is room temperature. In some aspects of the apparatuses described and/or claimed herein, the recirculation loop device, including its components such as an oxygen monitoring device, an oxygen scavenging device, a pump, etc., are external to the vessel, and can be removable and interchangeable from one vessel to another, or from one recirculation loop device to another.

[0079] The recirculation loop apparatus at least comprises devices or sensors for oxygen monitoring, and a device for oxygen scavenging or containing oxygen scavenging materials.

[0080] In one aspect, a pump, wherein the pump transports the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation loop apparatus. In many aspects of the apparatuses, the recirculation loop apparatus can also comprise a pump for transporting the chemical or the inert gas from the vessel and through the recirculation loop device. Many types of pumps can be employed in the recirculation loop device, and one of ordinary skill in the art can select a suitable pump in consideration of flows, and pressures needed, the chemical and physical properties of the chemical being circulated, and the need to minimize contact of the chemical being circulated with external air or water or sealing fluids or substances from the pump itself.

[0081] In a further aspect, the inert gas comprises nitrogen or argon, or a mixture thereof.

[0082] In some aspects of the apparatuses, the recirculation loop apparatus can also comprise an optional device or agent for scavenging water from the chemical, for example, if the devices or agents for oxygen scavenging produce water as a product of the oxygen scavenging. A wide variety of agents for scavenging water can be employed, such as for example small pore inorganic molecular sieves, clays, or zeolites, or strongly basic materials such as calcium hydride and the like.

[0083] The relative placement of the devices within the recirculation loop device, within the flow path for the chemical are not typically critical, though the oxygen level monitoring device is often placed prior to the pump, oxygen scavenger, or water scavenger. In many aspects of the devices and methods, the oxygen scavenger is placed prior to the water scavenger, so as to allow removal of water that can be generated in the oxygen scavenger. In many aspects of the devices and methods, the oxygen level monitoring precedes the oxygen scavenging. The rate and duration of recirculation of the chemical and/or inert gas can be determined by the speed and/or volume of output of the pump, which can be either manually or automatically varied in response to the measurement signals from the oxygen level monitoring device.

[0084] In one aspect, the pump, recirculation loop apparatus, oxygen scavenger, and monitoring device are external to the vessel. In a further aspect, the pump, recirculation loop apparatus, oxygen scavenger, and monitoring device are internal to the vessel.

[0085] In another aspect, the pump, recirculation loop apparatus, oxygen scavenger, and monitoring device are removable and interchangeable from one vessel to another.

[0086] The apparatuses disclosed herein can utilize the methods disclosed herein. D. EXAMPLE

[0087] The following example is put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and/or methods described and claimed herein are made, used, and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. There are numerous variations and combinations of reaction conditions, e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures and other reaction ranges and conditions that can be used to optimize the product purity and yield obtained from the described process. Only reasonable and routine experimentation will be required to optimize such process conditions.

a. Example 1

[0088] An example of one of the various aspects of the methods and apparatuses described and/or claimed herein, can be illustrated by FIG. 1, showing that the problem of peroxide formation when storing chemical compounds can be solved by storage of the compounds in a vessel (20) which is fitted with an external recirculation loop apparatus comprising a pump (18), monitoring device (22) and oxygen scavenger (24), wherein the recirculation loop apparatus circulates the chemical contents of the vessel without exposure to outside atmosphere. In this example of Figure 1, if the vessel was partially filled with a liquid chemical, the inlet for the recirculation loop apparatus at the top would transfer inert gas and/or vapors from the liquid toward the monitoring device and/or oxygen scavengers, then recirculate the gas into the bottom of the vessel, to purge and/or mix the liquid chemical with the deoxygenated and/or dehydrated gas. However, if the chemical was a gas (such as ethylene above its boiling point), the chemical would be re-circulated by the recirculation loop apparatus. Various arrangements of the inlets and outlets of the recirculation loop apparatus can be implemented by those of ordinary skill in the art to circulate the chemicals and/or inert gases or phases thereof.

[0089] The vessel is also fitted with an inlet (16) and outlet (14) port which permits purging of the vessel, recirculation loop apparatus, and/or chemical with a positive pressure stream of an inert gas, e.g., nitrogen, through the apparatus and/or chemical.

[0090] In accordance with the invention, as the chemical is first introduced into the vessel through a standard portal/fitting, the remaining air space is purged by introduction of the inert gas into the system for a time sufficient to displace the oxygen present. This time is shortened by the use of the circulating loop system which removes oxygen dissolved in the liquid. Once the oxygen has reached an acceptable level, e.g., below 10 ppm, or below about 5 ppm, or below about 1 ppm, the circulation can be discontinued and the vessel sealed with a slight positive pressure of inert gas. It is envisioned that the vessel, while now protected from exposure to the atmospheric oxygen, will be fitted with safety relief valves which would relieve any undo buildup of pressure within the vessel. In one aspect, normal operating temperatures are from about -20 °C to about 150 °C; for example from about 10 °C to about 80 °C or from about 15 °C to about 65 °C.

[0091] The methods and apparatus for removing oxygen from a chemical disclosed herein include at least the following embodiments:

[0092] Embodiment 1: A method for removing oxygen from a chemical; comprising: (1) purging a vessel containing a chemical with an inert gas; (2) circulating the chemical or the inert gas, or a mixture thereof, from the vessel through a recirculation loop apparatus that performs the steps comprising: i. monitoring the oxygen level; and ii. scavenging the oxygen; and (3) transporting the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation loop apparatus until an acceptable oxygen level has been reached; wherein the method does not comprise substantially any of an additive for scavenging a peroxide or preventing peroxide formation.

[0093] Embodiment 2: The method of embodiment 1, wherein the chemical forms at least one peroxide in the presence of oxygen.

[0094] Embodiment 3: The method of any of embodiments 1-2, wherein the chemical is a gas or vapor.

[0095] Embodiment 4: The method of any of embodiments 1-2, wherein the chemical is a liquid.

[0096] Embodiment 5: The method of any of embodiments 1-2 or 4, wherein the chemical is an organic liquid.

[0097] Embodiment 6: The method of any of embodiments 1-5 wherein the monitoring the oxygen level precedes the scavenging the oxygen.

[0098] Embodiment 7: The method of any of embodiments 1-6, wherein the chemical comprises an olefin, a diene or an ether.

[0099] Embodiment 8: The method of any one of embodiments 1-7, wherein the chemical is an olefin. [00100] Embodiment 9: The method of any one of embodiments 1-7, wherein the chemical is ethylene.

[00101] Embodiment 10: The method of any one of embodiments 1-7, wherein the chemical is a diene.

[00102] Embodiment 11: The method of any one of embodiments 1-7, wherein the chemical is butadiene.

[00103] Embodiment 12: The method of any one of embodiments 1-7, wherein the chemical comprises an ether.

[00104] Embodiment 13: The method of any one of embodiments 1-7, wherein the chemical comprises tetrahydrofuran (THF), diethyl ether, or methyl tertiary-butyl ether (MTBE), or a mixture thereof.

[00105] Embodiment 14: The method of any one of embodiments 1-13, wherein the inert gas comprises nitrogen or argon, or a mixture thereof.

[00106] Embodiment 15: The method of any one of embodiments 1- 14, wherein the scavenging the oxygen comprises using an activated metal.

[00107] Embodiment 16: The method of any of embodiments 1-15, wherein the scavenging the oxygen comprises using a support.

[00108] Embodiment 17: The method of any one of embodiments 1-16, wherein the scavenging the oxygen comprises using an organic compound with oxygen scavenging properties.

[00109] Embodiment 18: The method of embodiment 17, wherein the organic compound with oxygen scavenging properties comprises a hydroquinone.

[00110] Embodiment 19: An apparatus for removing oxygen from a chemical;

comprising: (1) a vessel, wherein the vessel is used to contain a chemical; wherein the vessel has one or more inlets and one or more outlets for an inert gas; and (2) a recirculation loop apparatus to and from the vessel, wherein the recirculation loop apparatus comprises: i. a pump, wherein the pump transports the chemical or the inert gas, or a mixture thereof, from the vessel through the recirculation loop apparatus; ii. a monitoring device, wherein the monitoring device measures the oxygen level; and iii. an oxygen scavenger.

[00111] Embodiment 20: The apparatus of embodiment 19, wherein the chemical forms at least one peroxide in the presence of oxygen.

[00112] Embodiment 21: The apparatus of any of embodiments 19-20, wherein the pump, recirculation loop apparatus, oxygen scavenger, and monitoring device are external to the vessel.

[00113] Embodiment 22: The apparatus of any of embodiments 19-21, wherein the pump, recirculation loop apparatus, oxygen scavenger, and monitoring device are removable and interchangeable from one vessel to another.

[00114] Embodiment 23: The apparatus of any of embodiments 19-22, wherein the vessel comprises a railroad tank car, a tanker trailer, a drum, an intermediate bulk container (IBC), or a storage container.

[00115] Throughout this application, various publications are referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the compounds, compositions and methods described herein.

[00116] Various modifications and variations can be made to the compounds, compositions, apparatuses, and methods described herein. Other aspects of the compounds, compositions and methods described herein will be apparent from consideration by one of ordinary skill in the art of the specification and practice of the compounds, compositions and methods disclosed herein. It is intended that the specification and examples be considered as exemplary.