KR101474209B1 - Extraction process using an ionic liquid - Google Patents

Abstract

Separating the alcohol from the non-polar solvent or separating the ketone from the nonpolar solvent or contacting the non-polar solvent with a mixture comprising at least one of an alcohol and a ketone and a mixture comprising a non-polar solvent, And separating the mixture of alcohol and ketone from the separated or non-polar solvent.

Description

[0001] EXTRACTION PROCESS USING AN IONIC LIQUID [0002]

<Cross reference of related application>

This application claims benefit of U.S. Provisional Application No. 60 / 838,957, filed on August 18, 2006, and U.S. Provisional Application No. 60 / 901,053, filed February 12, 2007. U.S. Provisional Application No. 60 / 901,053, incorporated herein by reference in its entirety.

The present invention relates to the separation of alcohols and ketones in mixtures with non-polar solvents such as alkanes, using ionic liquids. Specifically, the present invention relates to the separation of cycloalkanols, cycloalkanones and cycloalkanes.

Separation of a mixture of cyclohexanone and cyclohexanol from unreacted cyclohexane after oxidation of cyclohexane is an important step in the production of both adipic acid and caprolactam. Caprolactam is mainly used industrially as a monomer in the preparation of nylon-6. Adipic acid is a monomer used in the manufacture of nylon-6,6, among others.

Typically, cyclohexane is oxidized to a relatively low conversion of less than 10%. The major oxidation products of cyclohexane are cyclohexane hydroperoxide, cyclohexanol and cyclohexanone. In a typical commercial cyclohexane oxidation process, the cyclohexyl hydroperoxide is subsequently decomposed into cyclohexanol and cyclohexanone in the reactor or in separate unit operations. For the purpose of the present invention as a cyclohexane oxidation method, the above process can be explained in a general manner. The desired final oxidation product after decomposition of cyclohexyl hydroperoxide is a mixture of the main component cyclohexanone and cyclohexanol. The mixture should then be separated from the unreacted cyclohexane, and the unreacted cyclohexane can then be recycled, typically to the oxidation reaction. This separation is carried out by distillation commercially, and since most of the cyclohexane is recycled, this process step causes a high rate of process steam consumption.

Therefore, there is a need for alternative separation techniques that can reduce steam consumption and, as a result, reduce the substantial energy costs associated with separation through distillation.

In addition, the process for preparing caprolactam requires cyclohexanone which is substantially free of cyclohexanol as a starting material. At present, this level of purity is also achieved commercially through distillation, an energy intensive process.

Liquid-liquid or solvent separation processes (also known as liquid-liquid or solvent extraction processes) are well known in the art as a method for separating components of a mixture. Liquid-liquid separation is based on moving the component (s) from one liquid phase to another, and is used to selectively separate the separate component (s) from the mixture. When mixing two liquids that are immiscible, phase separation takes place and two liquid layers, also known as phases or fractions, are formed. The less dense liquid will form the upper layer, and the more dense the liquid will form the lower layer. The liquid-liquid separation depends on the different relative solubilities of the components in the two immiscible liquids. In particular, when the soluble component can be freely mixed with two immiscible liquids, the soluble component is dispensed between the two liquid phases formed thereby, and the soluble components are generally dissolved in one of the liquid phases to a greater extent than the other will be. Generally, in liquid-liquid separation, an aqueous phase or an aqueous phase and a substantially water-immiscible organic phase (including an organic solvent) are used. In this example, when one of the separable components is more soluble in the organic phase, it will separate and dissolve in the organic phase when the aqueous phase and the organic phase are mixed with, for example, an aqueous solution of two separate components. If the other detachable component is more soluble in the aqueous phase, the two detachable components will separate. Liquid-liquid separation may be an effective technique, but suitable liquids should be used. With respect to the separation of cycloalkanols and cycloalkanes from cycloalkanes, conventional aqueous phase / organic phase separation will not be possible because all three components are more soluble in the organic phase.

In addition, liquid-liquid extraction techniques can be performed using two organic phases that are much larger in one of the organic phases than the other in the solubility of the components to be extracted and are substantially immiscible with respect to each other. A drawback of the liquid-liquid extraction technique is that the final recovery of the extracted components from the original mixture can be complicated by the volatility of the extraction solvent. Typically the components of interest are finally recovered by distillation, but often the extraction solvent is similar in volatility to the desired product. Thus, recovery of the components of interest can be very difficult, and the process can be energy intensive in steam requirements. A feature of the present invention is that these constraints are avoided by using the ionic liquid (s) as the extraction solvent. Since the ionic liquid is substantially non-volatile, it does not interfere with recovery of the components of interest during the final recovery. Thus, recovery of the components can be accomplished by simple flash recovery in which the energy (e.g., steam) requirement is correspondingly reduced without requiring a complicated separation technique.

In order to prepare caprolactam by oxidation of cyclohexane, it is further necessary to separate cyclohexanol from cyclohexanone directly from a mixture of cyclohexanone and cyclohexanol or in the presence of cyclohexane. This is because the preparation of caprolactam requires only cyclohexanone as a starting material. Typically, this separation is carried out by distillation, and the separation of cyclohexanone from cyclohexanol requires a high capital investment cost and significant energy in the required distillation column. Liquid-liquid extraction techniques are not typically used for the separation of cyclohexanone and cyclohexanol because such extraction requires an extraction solvent that selectively removes one component from the mixture. Conventional solvents suitable for use in solvent extraction methods will not be able to selectively extract cyclohexanol from cyclohexanone.

In liquid-liquid separation, the distribution coefficient of a given separable component can be quoted as a measure of the extent to which the separable component is separated. In conventional liquid-liquid separation, the distribution coefficient equals the concentration of the separable component in the organic phase divided by the concentration of the separable component in the aqueous phase. The distribution coefficient may vary depending on a number of different parameters, for example temperature.

It is an object of the present invention to provide an improved method of separating alcohol from ketones in a mixture of ketone and alcohol in a non-polar solvent; And an improved method of separating alcohols and / or ketones from non-polar solvents. A specific object of the present invention is to provide an improved process for separating cycloalkanols from cycloalkanones in a mixture of cycloalkanols and cycloalkanones in a non-polar solvent (e.g., cycloalkane); And an improved process for separating cycloalkanol and / or cycloalkanone from a nonpolar solvent (such as a cycloalkane).

According to the present invention there is provided a process for separating an alcohol from a nonpolar solvent or separating the ketone from a nonpolar solvent or contacting the ketone with a nonpolar solvent comprising contacting at least one ionic liquid with at least one of an alcohol and a ketone and a mixture comprising a non- Or separating a mixture of an alcohol and a ketone from a non-polar solvent.

The difference in the distribution coefficients of cyclohexanol and cyclohexanone in these ionic liquids indicates the separation efficiency of cyclohexanol. These ionic liquids are therefore effective for the separation of cyclohexanol from cyclohexane and for the separation of cyclohexanol from a mixture of cyclohexanone and cyclohexane.

As used herein, the term "alcohol" includes non-cyclic and cyclic aliphatic alcohols, and in one embodiment refers to an (alkyl-OH) group and in alternate embodiments a (cycloalkyl-OH) group, Quot;

As used herein, the term "ketone" is acyclic and cyclic and include aliphatic ketones, in one embodiment (alkyl - (C = O) - alkyl) and refers to the group, according to the embodiment of the alternative embodiment (CH ₂₎ groups are (C Refers to a cyclic compound, i. E., "Cycloalkanone, " which corresponds to a cycloalkane substituted with a = O) group.

The term "alkane" as used herein refers to (alkyl-H), and the term "cycloalkane" refers to (cycloalkyl-H).

As used herein, the term "alkyl" refers to a straight or branched saturated monovalent hydrocarbon radical, especially one in which the number of carbon atoms is one quartile of 20. As a non-limiting example, suitable alkyl groups include methyl, ethyl, propyl, butyl, pentyl, hexyl, octyl, nonyl, dodecyl and eicosyl. The alkyl group may be substituted with the same or different one or more halogen atoms, but is preferably unsubstituted.

The term "cycloalkyl" as used herein refers to a cyclic saturated monovalent hydrocarbon radical having from 3 to 20 carbon atoms. By way of non-limiting example, suitable cycloalkyl groups include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, and cyclododecyl. Preferably, the cycloalkyl group has 5 to 12 carbon atoms. The cycloalkyl group may be substituted with the same or different one or more halogen atoms, but is preferably unsubstituted.

The term "non-polar solvent" as used herein refers to a compound that is immiscible with an ionic liquid. In one embodiment, the term "nonpolar solvent" refers to a solvent having a dielectric constant measured at 20 DEG C and atmospheric pressure according to ASTM D924-92 of 5 or less, preferably 3.0 or less, more preferably 2.5 or less. In a preferred embodiment, the term "non-polar solvent" refers to cyclic and non-cyclic aliphatic hydrocarbons, particularly cyclic and acyclic saturated aliphatic hydrocarbons, namely alkanes and cycloalkanes such as pentane, hexane, heptane, octane and cyclohexane. The nonpolar aliphatic hydrocarbon may be substituted with the same or different one or more halogen atoms, but is preferably unsubstituted.

Thus, in one embodiment of the invention, the cycloalkanol is separated from the nonpolar solvent, comprising contacting at least one ionic liquid with a mixture comprising at least one of a cycloalkanol and a cycloalkanone and a nonpolar solvent There is provided a method for separating a cycloalkanone from a nonpolar solvent or separating a cycloalkanol from a mixture of a cycloalkanone and a nonpolar solvent or separating a mixture of a cycloalkanol and a cycloalkanone from a nonpolar solvent.

In a further embodiment of the present invention, there is provided a process for the preparation of an alcohol, comprising contacting at least one ionic liquid with a mixture comprising at least one of an alcohol and a ketone and an alkane, wherein the alcohol and the ketone are non- Separating the ketone from the alkane, separating the alcohol from the mixture of the ketone and the alkane, or separating the mixture of the alcohol and the ketone from the alkane.

In this embodiment, the number of carbon atoms of the alcohol may be different from the number of carbon atoms of the separated ketone and / or alkane present in the mixture, but is preferably the same; The number of carbon atoms in the ketone may be different from the number of carbon atoms in the separated alcohol and / or alkane present in the mixture, but is preferably the same.

In a particularly preferred embodiment of the present invention there is provided a method of separating a cycloalkanol from a cycloalkane or contacting the cycloalkanol with a cycloalkane comprising contacting at least one ionic liquid with a mixture comprising at least one of a cycloalkanol and a cycloalkanone and a cycloalkane, There is provided a method for separating a cycloalkanone from an alkane or separating a cycloalkanol from a mixture of a cycloalkanone and a cycloalkane, or a method for separating a cycloalkanol and a cycloalkanone mixture from a cycloalkane.

In such an embodiment, the number of carbon atoms of the cycloalkanol may be different from the number of carbon atoms of the separated cycloalkanone and / or cycloalkane present in the mixture, but is preferably the same; The number of carbon atoms of the cycloalkanone may be different from the number of carbon atoms of the separated cycloalkanol and / or cycloalkane present in the mixture, but is preferably the same.

Therefore,

(i) separating the alcohol and / or the ketone from the corresponding aliphatic hydrocarbon, i.e. an alkane or cycloalkane having the corresponding number of carbon atoms; And separating the alcohol from the corresponding ketone and aliphatic hydrocarbon,

(ii) a method of separating an alcohol and / or a ketone from aliphatic hydrocarbons (for example, alkane or cycloalkane) having a different number of carbon atoms; And a method of separating the alcohol from the ketone and an aliphatic hydrocarbon, and

(iii) separating the alcohol and / or ketone from the nonpolar solvent defined herein, and separating the alcohol from the corresponding ketone and nonpolar solvent

.

Further, in the method described under (ii) and (iii) above, the number of carbon atoms of the alcohol and the ketone itself may be different from each other, but typically the number of carbon atoms thereof will be the same.

According to the present invention, especially when the alcohol is a cycloalkanol and the ketone is a cycloalkanone, more particularly when the alcohol is a cycloalkanol and the ketone is a cycloalkanone and the nonpolar solvent is a cycloalkane, the alcohol and / Or separating the alcohol from the ketone in a mixture of alcohol and ketone in the nonpolar solvent.

In one embodiment, the cycloalkyl group has 6 carbon atoms and in this case, the separation methods described herein are particularly suitable for separating cyclohexanol and / or cyclohexanone from cyclohexane and for separating cyclohexanol and cyclohexanone from cyclohexane And the like.

In another embodiment, the cycloalkyl group has 12 carbon atoms and in this case, the separation methods described herein are particularly useful for separating cyclododecanol and / or cyclododecanone from cyclododecane and for separating cyclododecanone and cyclododecanone It is related to the separation of cyclododecanol from decane.

Thus, the mixture to be separated accordingly is, for example, a cycloalkanol and a cycloalkane; Or cycloalkanones and cycloalkanes; Or a cycloalkanol, a cycloalkanone, and a cycloalkane.

The method of the present invention comprises liquid-liquid separation, wherein one of the liquid phases is an ionic liquid phase and the other is a non-polar solvent phase, such as an organic hydrocarbon phase substantially immiscible on the ionic liquid system. As used herein, the term " substantially immiscible "means immiscible to the extent that two separate phases are formed. Thus, the method of the present invention relies on the different relative solubilities / solubilities of the components / components to be separated, i.e., the separable component (s), in the ionic liquid phase and the nonpolar solvent phase. In particular, a separable component will be dispensed between the ionic liquid phase and the non-polar solvent phase, such that the separable component or each of the separable components dissolves more on the ionic liquid system.

Once contact is made, the mixture and the ionic liquid (s) comprising alcohol and / or ketone (s) in the nonpolar solvent (e.g., cycloalkanol and / or cycloalkanone in the cycloalkane) Lt; / RTI &gt; As used herein, the term "contacting" means combining the ionic liquid (s) with the mixture comprising alcohol and / or ketone in the non-polar solvent to form a separate mixture. The mixture comprising the alcohol and / or the ketone in the non-polar solvent and the ionic liquid (s) may be contacted in a container suitable for such contact (i.e., a reaction vessel).

Typically, to completely disperse the ionic liquid (s) in the overall mixture of alcohol and / or ketone in the nonpolar solvent, the separation mixture is vigorously shaken, mixed or stirred for a predetermined period of time Quot;). If the contact time is too short, the ionic liquid (s) will not be completely dispersed throughout the mixture comprising the alcohol and / or ketone in the non-polar solvent and the separation of the separable component (s) will be insufficient It will be appreciated that only a small portion of the separable component (s) present in the separation mixture will be separated. Increasing the contact time of the separation mixture will increase the dispersion of the mixture, including the alcohol and / or ketone in the ionic liquid (s) and the non-polar solvent, and will increase the efficiency of separation. That is, most of the separable component (s) in the separated mixture will be separated. This increase in separation efficiency with contact time is dependent on the separation conditions (e.g., the type of ionic liquid and the temperature, etc.) used until the largest possible fraction of the total amount of separable component (s) That is, until it is separated as far as possible. Thereafter, contacting the separation mixture for any extended period of time will not provide any advantage for the separation of the separable component (s). Thus, the contact time used herein is preferably greater than 30 seconds, more preferably greater than 60 seconds, and typically less than 5 minutes, but longer times may be used to achieve satisfactory results.

After vigorously shaking, mixing or stirring, the separated mixture is allowed to stand for another hour (hereinafter referred to as "settling time"). During the settling time, the separated mixture will be separated into an ionic liquid system and a non-polar solvent system. The settling time should be sufficiently long so that the ionic liquid phase system and the nonpolar solvent phase are completely separated, and when the system is completely separated, the system is said to be in equilibrium. The settling time is preferably greater than 1 minute, more preferably greater than 2 minutes, and typically less than 10 minutes, but longer times may be used to obtain satisfactory results.

A mixture comprising at least one of a cycloalkanol and a cycloalkanone in an alcohol and / or a ketone, especially a cycloalkane, in a nonpolar solvent may be formed by an oxidation step prior to the separation treatment. For example, in the case of the oxidation of a cycloalkane, such as cyclohexane, as described above, the oxidation step may be oxidized using air only or in the presence of cobalt or other transition metal catalyst, and then the resulting cyclohexyl hydroperoxide But is not limited to, thermal decomposition or other catalytic decomposition. For purposes of the present invention, the oxidation step followed by the cyclohexyl hydroperoxide decomposition step, followed by the separation or contacting step, is defined as the oxidation and separation cycle. A plurality of oxidation and separation circulation processes can be used. In this example, the cycloalkane-based phase or fraction produced by the separation can be recycled for further oxidation.

In addition, following the separation step, the ionic liquid phase can be physically separated from the nonpolar solvent phase. Such physical separation may be performed using any suitable apparatus. It is also possible to remove the separable component (s), such as cycloalkanol and / or cycloalkanone, in the ionic liquid system so that the ionic liquid (s) can be recycled, for example, Can be reused.

Commercial installations for liquid-liquid extraction contact and separation can generally be divided into two categories: stepwise and continuous (differential) contact. Typically, the stepped work involves a mixing step in a device, generally known as a mixer-stator, followed by a phase separation or settling step. The work may be performed in a sequential batch manner, in which case it is customary to perform alternating mixing and mixing operations in the same vessel. In addition, the work can be carried out in a continuous flow, for which the mixing and settling steps are usually carried out in separate vessels, but this is not always the case. In a continuous flow system, the required mixing time and settling time are obtained by a suitably sized facility volume or holdup. Examples of commercial mixing equipment known to those skilled in the art include an in-line static mixer, a jet mixer, an injector, an orifice or mixing nozzle, a valve, a centrifugal pump, a stirrer line mixer, a filled tube, Gas or steam stirred vessels and vessels with circulating flow loops. Examples of commercial and stationary equipment known to those skilled in the art include, but are not limited to, gravity buffers, decanters, centrifuge cyclones, centrifuges, stationary aids such as coalescers, separation membranes and electric field devices ). Any type of mixer and stator can be combined to create the steps. The steps may be arranged in a multi-stage cascade to achieve additional separation efficiency. In a multi-stage arrangement, various liquid flow process drawings such as counter-current flow, co-current flow, cross-current flow and step-flow can be used. A compact facility consisting of alternating mixing and stationary elements can be constructed.

The continuous (parallax) contact facility is typically arranged to provide multiple-stage countercurrent contact of the insoluble liquid without repeatedly and completely separating liquids from each other between the steps. However, it can also be arranged in a free flow or cross flow. The liquids remain in continuous contact with each other throughout the plant. Backflow is maintained by the density difference of the liquids with gravity or centrifugal force. Commercial facilities known to those skilled in the art include gravity operating extractors such as spray towers, packed towers or sieve tray towers; A rotary-disk contactor, a Mixco (Oldshue-Rushton) multi-mixer column, a Scheibel column, a Kuhni column, A gravity operation extractor including mechanical stirring such as a contact column, a liquid pulse tower and a reciprocating plate column; And a centrifuge extractor.

The separation process of the present invention may form one or more separation steps in the production of adipic acid or caprolactam. The separation step of such a process is traditionally carried out by distillation.

In embodiment (a), the separable component is a cycloalkanone, which is separated from the cycloalkane. The ionic liquid (s) are contacted with a mixture of cycloalkanone and cycloalkane. In this embodiment, the mixture of the ionic liquid (s) and the cycloalkanone and the cycloalkane is referred to as a separate mixture (a). The process of this embodiment involves liquid-liquid separation, wherein one of the liquid phases is an ionic liquid system and the other is a cycloalkane system that is substantially incompatible on the ionic liquid system. In such embodiments, the distribution coefficient of the cycloalkanone between the ionic liquid phase and the cycloalkane-based phase is greater than 1.5, preferably greater than 3.

In embodiment (b), the separable component is a cycloalkanol, which is separated from the cycloalkane. The ionic liquid (s) are brought into contact with a mixture of a cycloalkanol and a cycloalkane. In this embodiment, the mixture of ionic liquid (s) and cycloalkanol and cycloalkane is referred to as a separate mixture (b). The process of this embodiment involves liquid-liquid separation, wherein one of the liquid phases is an ionic liquid system and the other is a cycloalkane system that is substantially incompatible on the ionic liquid system. In such embodiments, the distribution coefficient of the cycloalkanol between the ionic liquid phase and the cycloalkane-based phase is greater than 1.5, preferably greater than 3.

In embodiment (c), the separable component is a cycloalkanol, which is separated from a mixture of cycloalkanone and cycloalkane. The ionic liquid (s) are contacted with a mixture of cycloalkanols, cycloalkanones and cycloalkanes. In this embodiment, the mixture of ionic liquid (s), and cycloalkanol, cycloalkanone, and cycloalkane is referred to as a separate mixture (c). The process of this embodiment involves liquid-liquid separation, wherein one of the liquid phases is an ionic liquid phase and the other liquid phase is a cycloalkane phase that is substantially incompatible on the ionic liquid system. The separation of the cycloalkanone from the cycloalkanol and the cycloalkanol from the cycloalkane according to the process of this embodiment is carried out in such a way that the distribution coefficient of the cycloalkanol between the ionic liquid system and the cycloalkane system is greater than 1 and the ionic liquid system And the distribution coefficient of the cycloalkanone between the phase and the cycloalkane-based phase is less than 1. This embodiment applies to the separation of cyclohexanol from cyclohexanone for the production of caprolactam. In such embodiments, the distribution coefficient of the cycloalkanol between the ionic liquid phase and the cycloalkane-based phase is greater than 1.5, preferably greater than 3.

In embodiment (d), the separable components are a mixture of a cycloalkanone and a cycloalkanol, which are separated from the cycloalkane. The ionic liquid (s) are contacted with a mixture of cycloalkanols, cycloalkanones and cycloalkanes. In such embodiments, the mixture of ionic liquid (s), and cycloalkanol, cycloalkanone, and cycloalkane is referred to as a separate mixture (d). The process of this embodiment comprises liquid-liquid separation, one of the liquid phases being an ionic liquid system and the other being a cycloalkane system substantially immiscible on the ionic liquid system. In such embodiments, the distribution coefficient of the cycloalkanol and cycloalkanone between the ionic liquid phase and the cycloalkane-based phase is greater than 1.5, preferably greater than 3.

In each of the embodiments (a) - (d), the mixture to be separated may also contain a substance that is not a cycloalkanol, a cycloalkanone, and a cycloalkane component. Depending on the distribution coefficients of these other materials between the ionic liquid phase and the cycloalkane phase, these other materials may be retained in the cycloalkane phase or separated ionically with the separable phase. In particular, cyclohexylhydroroxide (CHHP) may be present in a separate mixture of cyclohexanol, cyclohexanone and cyclohexane. Under these circumstances, the CHHP will be separated into ionic liquid systems with cyclohexanol and / or cyclohexanone.

It will be appreciated that the processes of embodiments (a) to (d) may also be applied in the general case in which the cycloalkanol, cycloalkanone and cyclohexane are replaced by alcohols, ketones and nonpolar solvents, respectively.

The ionic liquid (s) of the present invention may comprise a single ionic liquid or a mixture of two or more ionic liquids, i. E. Two, three, four, five and six different ionic liquids have. Typically, one or two, typically only one, ionic liquid is used.

Preferably, the ionic liquid (s) are selected from the group consisting of 1-alkylpyridinium, alkyl or polyalkylpyridinium, phosphonium (PR ₄ ⁺ ), alkyl or polyalkylphosphonium, imidazolium, alkyl or polyalkylimidazolium , Ammonium (NR ₄ ⁺ ), alkyl or polyalkylammonium, alkyl or polyalkylpyrazolium, alkyl or polyalkylpyrrolidinium, alkyl or polyalkyl azepinium, alkyloxonium or alkylsulfonium &Lt; / RTI &gt;

 Each R group of the phosphonium and ammonium cations may be independently selected from the group of substituents consisting of hydrogen, hydroxyl, alkyl, alkyl ether, alkyl ester, alkyl amide, alkyl carboxylic acid or sulfonate.

More preferably, the ionic liquid (s) comprises a cation selected from one or more of 1-alkylpyridinium, alkyl or polyalkylpyridinium, imidazolium, alkyl or polyalkylimidazolium.

When a mixture of two or more ionic liquids is used, the cations of each ionic liquid present in the mixture may be the same or different.

Preferably, the anion of the ionic liquid (s) is a halide, preferably chloride, bromide or iodide, nitrate, alkyl sulfate or alkyl polyalkoxysulfate such as methanesulfonate, trifluoromethanesulfonate And anions selected from the group consisting of hydrogen sulphonates, oxo anions of metals, and anions based on nitrogen, phosphorus, boron, silicon, selenium, tellurium and halogens. Suitable anions include bis (trifluoromethylsulfonyl) amide (NTf ₂ ^- ), tetrafluoroborate (BF ₄ ^- ), trifluoromethylsulfonyl (Tf ^- ), methoxyethylsulfonate, (Methoxypropoxy) ethylsulfate, ethylsulfonate, ethoxyethylsulfonate, 2-ethoxyethylsulfonate, (methoxypropoxy) propylsulfonate, 1- Methyl (diethoxy) ethylsulfonate, carboxylate, formate, acetate, dicyanimide, and tri (methoxyethoxy) ethylsulfonate. But are not limited to, fluoromethanesulfonate.

More preferably, the anion of the ionic liquid (s) is selected from the group consisting of alkyl sulfates or alkyl polyalkoxysulfates, bis (trifluoromethylsulfonyl) amide (NTf ₂ ^- ) and tetrafluoroborate (BF ₄ ^- ) It is selected from one or more.

When a mixture of two or more ionic liquids is used, the anions of each ionic liquid present in the mixture may be the same or different.

Preferably, the ionic liquid (s) will comprise one or more C ₂ -C ₆ alkyl groups. The C ₂ -C ₆ alkyl group may be a substituent of the anion or cation of the ionic liquid (s). More preferably, the C ₂ -C ₆ alkyl group is a substituent of the cation of the ionic liquid (s). When the ionic liquid (s) is comprised of a single ionic liquid, the single ionic liquid present preferably contains at least one C ₂ -C ₆ alkyl substituent. When the ionic liquid (s) is comprised of two or more ionic liquids, preferably at least one of the ionic liquids present contains one or more C ₂ -C ₆ alkyl substituents, Two or more of the ionic liquids contain one or more C ₂ -C ₆ alkyl substituents. That is, ionic liquids such as 2, 3, 4 and 5 of the ionic liquids present contain one or more C ₂ -C ₆ alkyl substituents. Most preferably, all of the ionic liquids which are at least one ionic liquid contain one or more C ₂ -C ₆ alkyl substituents.

The ionic liquid (s) of the present invention are preferably N-ethylpyridinium bis (trifluoromethanesulfonyl) amide, N-methyl-N'-butylimidazolium tetrafluoroborate, N- '-Butylimidazolium bis (trifluoromethanesulfonyl) amide, trimethyl (2-hydroxyethyl) ammonium bis (trifluoromethanesulfonyl) amide, N-methyl-N'- ethylimidazolium 2- Butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide, N-methyl-N'-butylimidazolium 2-methoxyethylsulfonate, N-methyl- N'-butylimidazolium bromide, N-methyl-N'-butylimidazolium 2-ethoxyethylsulfonate, N-methyl- Methyl (1-methoxyethoxy) ethylsulfonate, N-methyl-N'-butylimidazolium 1-methyl (diethoxy) ethylsulfonate, N-methyl-N- (butyl-4-sulfonic acid) Pyrrolidinium trifluoromethanesulfonate, or mixtures thereof. &Lt; RTI ID = 0.0 &gt;

Most preferably, the ionic liquid (s) is selected from the group consisting of N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide or N-methyl-N'-butylimidazolium 1- Lt; / RTI &gt; propoxy) propylsulfonate.

Particularly suitable ionic liquids for separating the alcohol from the non-polar solvent when the alcohol is a cycloalkanol (especially cyclohexanol) and the nonpolar solvent is a cycloalkane (especially cyclohexane) is N-ethylpyridinium bis N-methylimidazolium tetrafluoroborate, N-methyl-N'-butylimidazolium bis (trifluoromethanesulfonyl) amide, trimethyl N-methylimidazolium 2-methoxyethylsulfonate, N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide, Methylimidazolium 2-methoxyethylsulfonate, N-methyl-N'-butylimidazolium bromide, N-methyl-N'-butylimidazolium 2- Ethoxyethylsulfonate, N-methyl-N'-butylimidazolium 1- (1-methoxypropoxy) propylsulfonate, N-methyl- Methyl-N'-butylimidazolium 1-methyl (diethoxy) ethylsulfonate, N-methyl-N- (butyl Sulfonic acid) pyrrolidinium trifluoromethanesulfonate or mixtures thereof.

Especially when the alcohol is a cycloalkanol (especially cyclohexanol), the ketone is a cycloalkanone (in particular cyclohexanone) and the nonpolar solvent is a cycloalkane (in particular cyclohexane), alcohol is separated from a mixture of a nonpolar solvent and a ketone The most suitable ionic liquids to be used are N-methyl-N'-butylimidazolium bromide, N-methyl-N'-butylimidazolium 1- (1-methoxyethoxy) ethylsulfonate, N'-butyl imidazolium 2-ethoxyethylsulfonate, or a mixture thereof.

Particularly suitable ionic liquids for separating the ketone from the non-polar solvent when the ketone is a cycloalkanone (especially cyclohexanone) and the nonpolar solvent is a cycloalkane (especially cyclohexane) is N-ethylpyridinium bis N-methylimidazolium tetrafluoroborate, N-methyl-N'-butylimidazolium bis (trifluoromethanesulfonyl) amide, trimethyl N-methylimidazolium 2-methoxyethylsulfonate, N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide, Methylimidazolium 2-methoxyethylsulfonate, N-methyl-N'-butylimidazolium 1- (1-methoxypropoxy) propylsulfonate, N -Methyl-N'-butylimidazolium 1-methyl (diethoxy) ethylsulfonate, N-methyl-N- (butyl-4-sulfonic acid) pyrrolidinium triple Lt; / RTI &gt; methanesulfonate, or mixtures thereof.

In particular, when the alcohol is a cycloalkanol (especially cyclohexanol), the ketone is a cycloalkanone (especially cyclohexanone) and the nonpolar solvent is a cycloalkane (especially cyclohexane), a mixture of an alcohol and a ketone is separated The most suitable ionic liquids to be used are N-ethylpyridinium bis (trifluoromethanesulfonyl) amide, N-methyl-N'-butylimidazolium tetrafluoroborate, N-methyl-N'- (Trifluoromethanesulfonyl) amide, trimethyl (2-hydroxyethyl) ammonium bis (trifluoromethanesulfonyl) amide, N-methyl-N'-ethylimidazolium 2-methoxyethylsulfonate N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide, N-methyl-N'-butylimidazolium 2-methoxyethylsulfonate, N-methyl- Imidazolium 1- (1-methoxypropoxy) propylsulfonate, N-methyl-N'-butylimidazolium 1-methyl (Diethoxy) ethylsulfonate, N-methyl-N- (butyl-4-sulfonic acid) pyrrolidinium trifluoromethanesulfonate or a mixture thereof.

The term "ionic liquid" as used herein refers to an ionic compound that is liquid at less than 100 &lt; 0 &gt; C.

The term "distribution coefficient" as used herein in reference to liquid-liquid separation refers to the concentration of the separable component in the ionic liquid system phase divided by the concentration of the separable component in the non-polar solvent system. These concentrations are measured after vigorous stirring of the separating mixture and then standing, that is, equilibrium is reached.

The present invention is further illustrated by the following examples. It is to be understood that the embodiment is for purposes of illustration only and is not intended to limit the invention described above. Modifications of the details may be made without departing from the scope of the present invention.

Example

(i) Cyclohexanol / Cyclohexanone / cyclohexane

The present invention is exemplified by separating cyclohexanol and cyclohexanone from cyclohexane using general methods and calculating the production distribution coefficient. To simplify this example, the same volume of cyclohexane and ionic liquid was used. However, it should be noted that the volume of the ionic liquid actually used is preferably a small fraction of the volume of cyclohexane. It should also be noted that since the distribution coefficient is independent of the volume, the data obtained for the isometric experiment will correspond to commercial applications in which the ionic liquid and cyclohexane may not be isobaric. The general method used for all examples was as follows.

Stock solution: 250 mg of cyclohexanone (molecular weight is 100 gmol ^-1 ) and cyclohexanone (molecular weight is 98 gmol ^-1 ) in 10 g of cyclohexane (molecular weight is 84 gmol ^-1 ) and 250 mg.

Method: 1 mL (0.8 g) of stock solution (20 mg each of cyclohexanol and cyclohexanone) was added to 1 mL of ionic liquid and stirred vigorously. After the settling time and complete phase separation, 3 drops of the upper layer were placed in the vial and filled with ethylene chloride. Using gas chromatographic analysis, the molar number of separable components in each liquid phase was obtained. Then, the separation distribution coefficient was calculated.

Further, Hnmr (hydrogen nuclear magnetic resonance) was measured in each layer. In all cases, the cyclohexane or cyclohexanone layer contained less than 5 mole% of the ionic liquid, and in most cases the amount of ionic liquid in the cyclohexane-based layer was undetectable.

The following Tables 1a to 1c show the results of a specific example compared to water and DMSO (dimethylsulfoxide), where D is the distribution coefficient.

<Table 1a>

<Table 1b>

<Table 1c>

The difference in the distribution coefficients of cyclohexanol and cyclohexanone in these ionic liquids indicates the separation efficiency of cyclohexanol. These ionic liquids are therefore effective for the separation of cyclohexanol from cyclohexane and for the separation of cyclohexanol from a mixture of cyclohexanone and cyclohexane.

(ii) octanol / octanone / octane

In order to study the extraction of octanol and 2-octanone from octane using an ionic liquid, a corresponding series of experiments were performed. The results are shown in Table 2 below and the IL / octane distribution coefficient was calculated as the concentration of substrate in IL divided by the concentration of substrate in octane.

<Table 2>

Differences in the distribution coefficients of octanol and 2-octaone in these ionic liquids are due to the possibility of separating the octanol and / or 2-octa from the octane (Example 15) and of the octanol from a mixture of 2-octanone and octane (Examples 16 to 18).

Claims (21)

(a) a step of decomposing the cycloalkyl hydroperoxide after the step of oxidizing the cycloalkane,
(b) contacting the first mixture comprising at least one of the cycloalkanol and the cycloalkanone and the cycloalkane produced in step (a) with at least one ionic liquid to form a second mixture, wherein the oxidation The step, the decomposition step and the contact step are defined as one oxidation and separation cycle process,
(c) separating the second mixture into two phases, the first phase being an ionic liquid system and the second phase being a cycloalkane system, and
(d) separating the first and second phases,
Wherein the cation of the at least one ionic liquid is selected from the group consisting of 1-alkylpyridinium, alkyl or polyalkylpyridinium, phosphonium, alkyl or polyalkylphosphonium, imidazolium, alkyl or polyalkylimidazolium, Alkyl or polyalkylpyrrolidinium, alkyl or polyalkyllazepinium, alkyloxonium or alkylsulfonium, wherein the anion of the at least one ionic liquid Wherein the halide is selected from one or more of halides, nitrates, alkyl sulfates or alkyl polyalkoxy sulfates, oxo anions of metals and anions based on nitrogen, phosphorus, boron, silicon, selenium, tellurium,
The two separate phases reach equilibrium and the distribution coefficient of the cycloalkanol between the ionic liquid system phase and the cycloalkane system phase at the equilibrium exceeds 1 and the cyclic alkanol system between the ionic liquid system phase and the cycloalkane system phase A method for separating a cycloalkanol from a mixture of a cycloalkanone and a cycloalkane, the distribution coefficient of which is less than 1. (a) a step of decomposing the cycloalkyl hydroperoxide after the step of oxidizing the cycloalkane,
(b) contacting the first mixture comprising at least one of the cycloalkanol and the cycloalkanone and the cycloalkane produced in step (a) with at least one ionic liquid to form a second mixture, wherein the oxidation The step, the decomposition step and the contact step are defined as one oxidation and separation cycle process,
(c) separating the second mixture into two phases, the first phase being an ionic liquid system and the second phase being a cycloalkane system, and
(d) separating the first and second phases,
Wherein the cation of the at least one ionic liquid is selected from the group consisting of 1-alkylpyridinium, alkyl or polyalkylpyridinium, phosphonium, alkyl or polyalkylphosphonium, imidazolium, alkyl or polyalkylimidazolium, Alkyl or polyalkylpyrrolidinium, alkyl or polyalkyllazepinium, alkyloxonium or alkylsulfonium, wherein the anion of the at least one ionic liquid Wherein the halide is selected from one or more of halides, nitrates, alkyl sulfates or alkyl polyalkoxy sulfates, oxo anions of metals and anions based on nitrogen, phosphorus, boron, silicon, selenium, tellurium,
Wherein the two separate phases reach equilibrium and the distribution coefficient of the cycloalkanol between the ionic liquid system phase and the cycloalkane system phase at equilibrium is greater than 1.5. (a) a step of decomposing the cycloalkyl hydroperoxide after the step of oxidizing the cycloalkane,
(b) contacting the first mixture comprising at least one of the cycloalkanol and the cycloalkanone and the cycloalkane produced in step (a) with at least one ionic liquid to form a second mixture, wherein the oxidation The step, the decomposition step and the contact step are defined as one oxidation and separation cycle process,
(c) separating the second mixture into two phases, the first phase being an ionic liquid system and the second phase being a cycloalkane system, and
(d) separating the first and second phases,
Wherein the cation of the at least one ionic liquid is selected from the group consisting of 1-alkylpyridinium, alkyl or polyalkylpyridinium, phosphonium, alkyl or polyalkylphosphonium, imidazolium, alkyl or polyalkylimidazolium, Alkyl or polyalkylpyrrolidinium, alkyl or polyalkyllazepinium, alkyloxonium or alkylsulfonium, wherein the anion of the at least one ionic liquid Wherein the halide is selected from one or more of halides, nitrates, alkyl sulfates or alkyl polyalkoxy sulfates, oxo anions of metals and anions based on nitrogen, phosphorus, boron, silicon, selenium, tellurium,
Wherein the two separate phases reach equilibrium and the distribution coefficient of the cycloalkanone between the ionic liquid phase and the cycloalkane phase in the equilibrium is greater than 1.5. (a) a step of decomposing the cycloalkyl hydroperoxide after the step of oxidizing the cycloalkane,
(b) contacting the first mixture comprising at least one of the cycloalkanol and the cycloalkanone and the cycloalkane produced in step (a) with at least one ionic liquid to form a second mixture, wherein the oxidation The step, the decomposition step and the contact step are defined as one oxidation and separation cycle process,
(c) separating the second mixture into two phases, the first phase being an ionic liquid system and the second phase being a cycloalkane system, and
(d) separating the first and second phases,
Wherein the cation of the at least one ionic liquid is selected from the group consisting of 1-alkylpyridinium, alkyl or polyalkylpyridinium, phosphonium, alkyl or polyalkylphosphonium, imidazolium, alkyl or polyalkylimidazolium, Alkyl or polyalkylpyrrolidinium, alkyl or polyalkyllazepinium, alkyloxonium or alkylsulfonium, wherein the anion of the at least one ionic liquid Wherein the halide is selected from one or more of halides, nitrates, alkyl sulfates or alkyl polyalkoxy sulfates, oxo anions of metals and anions based on nitrogen, phosphorus, boron, silicon, selenium, tellurium,
Separating the mixture of the cycloalkanone and the cycloalkanol from the cycloalkane with the distribution coefficient of the cycloalkanone between the ionic liquid system phase and the cycloalkane system phase being greater than 1.5 in the equilibrium state How to. The method according to any one of claims 1 to 4, wherein the cycloalkane has 5 to 12 carbon atoms. The method of claim 1, wherein two separate phases are allowed to reach equilibrium and the distribution coefficient of the cycloalkanol between the ionic liquid system phase and the cycloalkane system phase at equilibrium is greater than 1.5. A method for separating a mixture and a cycloalkanol. The method of separating a cycloalkanol from a mixture of cycloalkanone and cycloalkane according to claim 6, wherein the distribution coefficient of the cycloalkanol is more than 3. The method of separating a cycloalkane and a cycloalkanol according to claim 2, wherein the distribution coefficient of the cycloalkanol is more than 3. The method of separating a cycloalkane and a cycloalkanone according to claim 3, wherein the distribution coefficient of the cycloalkane exceeds 3. The method of separating a cycloalkane from a mixture of a cycloalkanone and a cycloalkanol according to claim 4, wherein the distribution coefficient of the cycloalkane exceeds 3. 11. The method according to any one of claims 1 to 4 and 6 to 10, wherein the number of carbon atoms of the cycloalkanol, the cycloalkanone and the cycloalkane is 3 to 20, respectively. 11. The method according to any one of claims 1 to 4 and 6 to 10, wherein the cycloalkanol is cyclohexanol, the cycloalkanone is cyclohexanone, and the cycloalkane is cyclohexane. 11. The process according to any one of claims 1 to 4 and 6 to 10, wherein the cycloalkanol is cyclododecanol, the cycloalkanone is cyclododecanone and the cycloalkane is cyclododecane. A process according to any one of claims 1 to 4 and 6 to 10, wherein the cycloalkane-based phase or fraction produced by said separation is recycled for oxidation, comprising a plurality of oxidation and separation cycles Way. 15. The method of claim 14, wherein after equilibrium is reached, one or more ionic liquid system phases are physically separated from the cycloalkane system phase, and one or more ionic liquids and a cycloalkanol, cycloalkanone, And recycling the at least one ionic liquid. 11. The process according to any one of claims 1 to 4 and 6 to 10, wherein the at least one ionic liquid comprises a mixture of two or more ionic liquids. 11. A process according to any one of claims 1 to 4 and 6 to 10, wherein the anion of the at least one ionic liquid is selected from the group consisting of chloride, bromide, iodide, methanesulfonate, trifluoromethanesulfonate And a hydrogen sulphonate. 11. A process according to any one of claims 1 to 4 and 6 to 10 wherein at least one of the ionic liquids comprises at least one C ₂ -C ₆ alkyl group, Wherein the alkyl group can be present in the anion or cation of the at least one ionic liquid. 11. A process according to any one of claims 1 to 4 and 6 to 10, wherein said at least one ionic liquid is selected from the group consisting of N-ethylpyridinium bis (trifluoromethanesulfonyl) amide, N-methyl- N'-butylimidazolium tetrafluoroborate, N-methyl-N'-butylimidazolium bis (trifluoromethanesulfonyl) amide, trimethyl (2-hydroxyethyl) ammonium bis Methyl-N'-ethylimidazolium 2-methoxyethylsulfonate, N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide, N- Butylimidazolium 2-methoxyethylsulfonate, N-methyl-N'-butylimidazolium bromide, N-methyl-N'-ethylimidazolium 2-ethoxyethylsulfonate, N-methyl-N Butylimidazolium 1- (1-methoxypropoxy) propylsulfonate, N-methyl-N'-butylimidazolium 1- (1-methoxyethoxy) ethylsulfonate, N- '-Butylimidazolium 1-methyl (Diethoxy) ethylsulfonate, or N-methyl-N- (butyl-4-sulfonic acid) pyrrolidinium trifluoromethanesulfonate or a mixture thereof. 20. The process of claim 19, wherein said at least one ionic liquid is N-butyl-N-methylpyrrolidinium bis (trifluoromethanesulfonyl) amide. 20. The process of claim 19, wherein said at least one ionic liquid is N-methyl-N'-butylimidazolium 1- (1-methoxypropoxy) propylsulfonate.