KR910003108B1 - Separation of indene from feedstreams containing indene in admixture with other substances - Google Patents

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Description

Separation of indene from indene containing feed stream in mixture with other materials

1A, 1B and 2-8 are graphs showing the experimental results of indene separation by the method of the present invention.

The present invention relates to the technical field of fixed bed adsorptive separation, and more particularly to an improved process for separating indene from petrochemical feedstocks or composites containing indene in a mixture with other materials.

Indene has been used in the production of synthetic resins such as coumarone-indene resins, but has recently been used as a high purity monomer to improve the surface properties of polymers with minimal loss to vaporization due to comonomers and high vapor pressures of other resins.

Conventional methods for obtaining high purity indenes include centrifugation, distillation and crystallization of indene containing naphthacracker pyrolysis oils. There are many announcements related to the removal of impurities from various petroleum fractions, such as naphtha and naphthalene. These references point to group selection for impurity-containing indenes but do not imply high selectivity for indenes themselves. Moreover, no method for recovering indene from the adsorbent is presented. In the present invention, the selection of the suspending agent to recover only indene is an important step in order to remove other less adsorbed feed components before desorbing indene. For example, there are references by the following people: Jean et al. Preprint Papers A. Chem. Soc., Div Fuel Chem. 32 (3) 262-5 (CA 105 (12): 10017y): Kondratov et al. Zh. Fiz. Khim., 50 (3) 801 (CA 84 (24): 170137b): Kondratov et al., Kaks Khim. (9) 37-43 (CA 90 (5) 38709j).

Vykhristyuk et al., Koks khim. (2) The paper by 38-41 (CA 94: 208588 W) describes the removal of many impurities from naphthalene by treatment with a NaX zeolite adsorbent. In addition, the authors are interested in the removal of all forms of small amounts of impurities from the fuel, and do not deal with impurity recovery or indene recovery from residual contaminants.

However, it is an object of the present invention to obtain high purity forms of indene by high selective chromatography adsorptive separation from indene containing mixtures in mixtures with other materials. Such other materials include crude oil fractions such as naphtha, petrochemical feedstocks of naphthalene, for example preparation mixtures such as naphtha cracker pyrolysis oils, dehydrogenation or cyclization products containing aromatics in mixtures with indene, and the like. It is not separated easily and economically by means of being. Providing a desorbent for selectively exporting indene from an indene-rich adsorbent due to the adsorption step of the present invention having sufficient decomposition to obtain an indene product comprising actually reduced impurities and other feedstocks It is an object of the invention. Preferred desorbents are toluene but benzene and fluoro benzene and other alkyl- or halogen-substituted monocyclic aromatic liquids can also be used in the present invention.

If the indene-rich product of the present invention is used as a feed material, the aforementioned indene crystallization method is very effective and economical, so it is thought that it will reduce the total cost of obtaining high purity indene.

In summary, the present invention specifically relates to a process for separating indene from a feed mixture comprising a petroleum fraction or from a production product mixture containing indene, comprising an adsorbent comprising an X or Y zeolite and exhibiting selectivity to indene Since it has an exchangeable cation site that is in contact with the mixture in the adsorption state of the indene adsorption portion including the exchanged with sodium or potassium ions, selectively recover the indene-rich extract in the desorption step using one of the preferred adsorbents of the present invention do. The water content of the X-type zeolite plays an important role in the economy and purity of indene recovery by the method. The water concentration in the zeolite is preferably 1-8% by weight, but in terms of economics, the amount of water should be balanced between the selectivity of indene, the selectivity increases as the concentration decreases, and the indene is recovered. Desorbent flow needed to decrease with increasing water concentration. In order to obtain the best selectivity with a minimum amount of desorbent to recover only indene and to remove from the feedstock many substances with similar boiling points of similar structures contained in the above mentioned feedstocks, the optimum concentration of moisture is 4-7 wt. % Range.

The present invention specifically includes detailed descriptions of feed mixtures, adsorbents, desorbents and operating conditions, all of which are described below as aspects of the invention, respectively.

The present invention relates to a process for separating indene from raw material containing indene by adsorption chromatography using Na- or K-exchanged X or Y zeolites with suitable desorbents.

For the purposes of the present invention, various terms used below are defined in the following manner.

A "feed mixture" is a mixture containing one or more extracts and one or more extracts which can be separated by the present invention. "Feedstream" refers to a feedstream that passes through an adsorbent used in the present invention.

An "extract component" is a type of compound that is more selectively adsorbed by an adsorbent, and an "extract component" is a type of less adsorbed type. "Desorbable material" means a material that can typically desorb the extract component. "Desorbent" or "desorption suction" refers to a class of desorbents that pass through an adsorbent. "Residual residue" or "duty discharge" means a class of residual components removed from the adsorbent. The composition of the residues can vary from almost 100% desorbent to almost 100% of the residue. "Extract" or "extract" means a stream from which the adsorbate desorbed by the desorbent is removed from the adsorbent. Likewise, the composition of extracts can vary from nearly 100% desorbent to nearly 100% extract. At least a portion of the extract and preferably at least a portion of the weight residues removed in the present separation process pass through separation means (typically a separator) where at least a portion of the desorbent material is separated to produce the extraction product and the weight product. . "Extract product" and "church product" mean a product produced by the present invention so as to contain a higher concentration of the extract component and the extract component than the concentrations present in the extracts and the root residues, respectively.

Adsorbents used in the present invention for selectively adsorbing indene from petrochemical mixtures include X- and Y-type crystalline aluminosilicates or zeolites, which are silicon-oriented SiO interconnected by sharing common oxygen atoms. _It is described as a three-dimensional network of basic structural units consisting of ₄ and AlO ₄ tetrahedra of aluminum centers. The space between the tetrahedrons is filled with water molecules, which then form a crystalline structure in which channels of stereomolecules are intertwined as a result of dehydration and partial dehydration.

Thus, crystalline aluminosilicates are sometimes referred to as molecular sieves, and separation by molecular sieve is generally considered to physically "filter" small molecules from large molecules in the feed mixture. However, in separating indenes from complex petrochemical mixtures, separation occurs due to the treatment of the physicochemical attraction between each component and the adsorbent rather than a simple difference in the physical size of the molecules.

Preferred crystalline aluminosilicates in hydrated form usually contain a zeolite represented by the following formula (I).

M _{2 / n} O: Al ₂ O ₃ : WSiO ₂ : yH ₂ O In the above formula, “M” is a cation for balancing the electric valence of the tetrahedron and is commonly referred to as an exchangeable cation moiety, and “n” is a cation of Valence means, "W" represents moles of SiO ₂ and "Y" represents moles of water. The cation will be any of a number of cations described in detail below.

Adsorbents including zeolites of X-type and Y-type structures are particularly preferred for adsorptive separation of indene. Zeolites are described and defined in US Pat. Nos. 2,882,244 and 3,130,007, respectively. As used herein, the zeolites of "X-type structure" and "Y-type structure" include all zeolites having the general structural formula shown in the two patents mentioned above.

X- and Y-type structure zeolites in hydrated and partially hydrated form may represent the mole oxides shown in the following formulas (2) and (3).

[Equation 2]

(0.9 ± 0.2) M _{2 / n} 0: Al ₂ O ₃ : (2.5 ± 0.5) SiO ₂ : yH ₂ O

[Equation 3]

(0.9 ± 0.2) M _{2 / n} 0: Al ₂ O ₃ : WSiO ₂ : yH ₂ O

Wherein "M" represents at least one cation having a valence of 3 or less, "n" represents a valence of "M", "W" is at least 3.0 and up to 6 and "y" is the presence of "M" The maximum value is about 9, which indicates the degree of hydration of crystals.

As used herein, the terms "form X zeolite" and "form Y zeolite" refer to forms X- and Y-structured zeolites, including sodium and potassium cations such as the cation "M" as indicated above in general, For example, it also refers to the inclusion of another cation such as an alkali metal and an alkaline earth metal, such as a cation included in the Periodic Tables IA and IIA. Typically, as initially prepared, both Form X and Form Y structure zeolites exist primarily in the sodium form. The term "exchanged cation site" refers to a place in the zeolite occupied by the cation "M". Such cations, which are usually sodium, may be substituted or exchanged for other specific cations such as those described above, depending on the type of zeolite that modified the zeolite's properties. Zeolites prepared for use in the present invention are form Y ions exchanged using sodium cations.

Cations occupying exchangeable cation sites in the zeolite can be exchanged with other cations by ion exchange methods known to those of ordinary skill in the art of crystalline aluminosilicates.

Such a method is generally carried out by contacting said zeolite or adsorbate comprising said zeolite with an aqueous solution of said cation or a soluble salt of a cation preferably disposed on said zeolite. After the desired degree of exchange has taken place, the Sieve is removed from the aqueous solution, washed and dried to give the desired moisture content. Such a method allows the replacement of the sodium cation and non-sodium cations as impurities in the sodium-X and sodium-Y zeolites, which may occupy exchangeable sites, partially or essentially completely with other cations. The zeolites used in the process of the invention preferably comprise cations selected from the group consisting of alkali metals and in particular sodium and potassium at the cation sites which can be exchanged.

Typically, the adsorbents used in the independent process include zeolite crystals and amorphous materials. The zeolite will typically be present in the adsorbent in an amount ranging from about 25 wt% to 98 wt% based on the nonvolatile composition. Non-volatile compositions are generally determined after sintering the adsorbent at 900 ° C. to dry all volatiles. The remainder of the adsorbent is an amorphous material such as a silica-alumina mixture or compound such as silica or mud and the material is well mixed with the small particles of the zeolitic material. Such amorphous materials are appendages for the method of making zeolites (for example, intentionally not fully purifying the zeolite during zeolite preparation) or it may be added to a relatively pure zeolite, but in any case its purpose is to As a binder, it helps to form or aggregate the hard crystalline particles of the zeolite. Normally, the adsorbent will be in the form of particles such as extracts, agglomerates, tablets, prototypes or granules having the desired particle size range. The zeolitic adsorbents used in this process preferably have a particle size range of about 16-40 mesh (standard U.S. mesh) corresponding to apertures of 0.42-1.19 mm. The adsorbent is preferably wrapped in a vertical column through which the raw material mixture passes, preferably underneath.

The adsorbents of the present invention have been found to have very high adsorption selectivity for indene compared to other components of the petrochemical raw material mixture.

In general, relative selectivity may be indicated for one raw material compound as compared to the other, as well as between specific raw material mixture components and desorbents. As used herein, the selectivity β is defined as the ratio of the same two components in the adsorption phase to the two components in the non-adsorption phase at equilibrium conditions. Relative selectivity is represented by the following equation (1).

Equation (1)

Where C and D are the two components of the raw material expressed in weight percent and A and U represent the adsorptive and nonadsorbed phases, respectively. The equilibrium condition is determined if the raw material passing through the absorbent layer does not change the composition after contacting the absorbent layer. In other words, there is no pure transition of material between the adsorptive and adsorptive phases. If the selectivity of both components approaches 1.0, there is no desirable adsorption of one component to the other by the adsorbent. When comparing the selectivity by component C with adsorbent of component D with respect to component D, (β) greater than 1.0 indicates the desired adsorption of component C in said adsorbent. (Β) less than 1.0 indicates that component D is preferably absorbed leaving the adsorption phase rich in component C and the adsorption phase rich in component D. Ideally, the desorbent has a selectivity of about 1 or slightly less than 1 for all extract components so that all components can be desorbed as a layer with a reasonable flow rate of desorbent and the extract components are subjected to subsequent adsorption steps. The adsorbent can be replaced. Separation of the extract component from the weight residue is theoretically possible when the selectivity of the adsorbent for the extraction component is greater than 1 for the weight residue, but it is preferred when such selectivity approaches a value of 2. As with relative volatility, the higher the selectivity, the easier it is to perform the separation. The higher the selectivity, the smaller the amount of adsorbent to be used.

Other important features of the adsorbent are the exchange rate of the extract component and the desorbent material in the raw material mixture and the adsorption capacity for the extract component. The rate of exchange, ie, the rate of desorption relative to the extract component, is directly related to the amount of desorbent that must be used in the process for the purpose of recovering the extract component from the adsorbent; The faster the exchange rate, the lower the amount of desorbent material required to remove the extract components, thus reducing the cost of the process. The faster the exchange rate, the less desorbent material is pumped into the process and separated from the extract stream for regeneration purposes. The ability to adsorb a particular volume of extract component is also essential and the greater the capacity, the smaller the amount of adsorbent required for a given separation process.

The adsorbents may be used in the form of a dense compact stationary phase that selectively contacts the raw material mixture and the desorbent material. In the simplest embodiment of the present invention the adsorbent is used in the form of a single stationary phase, in which case the process is carried out only continuously. In another embodiment, two or more stationary phases are used in contact with a suitable valve to allow the desorbent material to pass through one or more other phases in the set as the feed mixture passes through one or more adsorbent beds. . The flow of the raw material mixture and the desorbent material may proceed in the up or down direction of the desorbent. However, it is preferable to use any of the conventional apparatuses used in the stationary backflow flow system because they have a much greater separation efficiency than fixed bed adsorbent systems. In mobile or simulated mobile phase processes, the adsorption and desorption processes are carried out continuously so that both the extract and the residue streams are continuously produced and the feed and desorbent streams can be used continuously. One preferred embodiment of the process of the present invention utilizes what is known in the art as simulated mobile phase countercurrent flow systems. The process principle and sequence of the flow system are disclosed in US Pat. No. 2,985,589, which is incorporated herein by reference. In the system described above, multiple liquid access points in the lower part of the adsorption chamber, which simulate the upward movement of the adsorbent contained in the adsorption chamber, gradually move. At any point in time only four of the access lines are active; These feedstock inlet streams, desorbent inlet streams, propellant outlet streams, and extract outlet stream access lines. Consistent with this simulated upward motion of the solid adsorbent is the motion of the liquid occupying the void volume of the adsorbent packing layer. Accordingly, the real circulation pump moves through different zones requiring different flow rates as the cycle moves from the top of the adsorption chamber to the bottom by the pump while maintaining the countercurrent contact. It is also possible to install a programmed flow rate controller for the purpose of fixing and adjusting the flow rate.

The active liquid access points effectively divide the adsorption chamber into separate zones, each having a different function. In this embodiment of the invention, there are generally three separate operating zones for the purpose of advancing the process, and optionally a fourth zone may be used.

Zone I, the adsorption band, is defined as the desorbent zone located between the feed import stream and the propellant effluent stream. In this zone, the raw materials come into contact with the adsorbent to adsorb the extract components and the propellant stream is recovered. The overall flow through the band is from the feed stream entering the band to the propellant stream exiting the band, where the flow in the band is considered to be a downstream stream from the feed inlet to the propellant outflow stream.

The immediate upstream to the fluid flow in zone I is the refinement zone, ie zone II. The refining zone is defined as an adsorbent located between the extract effluent stream and the feed inlet stream. The basic processes in zone II may utilize multiple adsorptive separation processes, both liquid and vapor phase operations of all propellants and non-selective void volumes of the adsorbent transported to zone II by adsorbent transfer into the zone. Liquid phase operation is preferred in this process because the liquid phase operation has lower temperature conditions than the gas phase operation and the high yield yields the extraction product. Among the adsorption conditions, the temperature range is about 20 ° C. to about 200 ° C., and about 20 ° C. to about 100 ° C. is more preferable, and the pressure range may be about atmospheric pressure or sufficient pressure to provide a liquid phase. The temperature and pressure range of the desorption conditions are the same as those used for the adsorption conditions.

The size of the unit that can be used in the process of the present invention can be in the range of intermediate test plant (e.g., U.S. Patent No. 3,706,812) to normal scale, and the flow rate can be reduced to several cc per hour or to thousands of gallons per hour. have.

The adsorption characteristics such as adsorption capacity, selectivity and exchange rate are measured by using dynamic test equipment to test various adsorbents with specific feed mixture and desorbent materials. The apparatus consists of an adsorption chamber of approximately 70 cc capacity having an inlet and an outlet at opposite ends of the chamber. This chamber is contained within the temperature control means, and in addition a pressure control device is used to operate the chamber at a constant pressure of regulation. Quantitative and qualitative analyzers such as refractometers, polarimeters and chromatography can be connected to the outlet line of the chamber and used to quantify or qualitatively analyze one or more components of the effluent from the adsorption chamber.

Pulse tests performed in accordance with the apparatus and the following general methods are used to specify the selectivity and data other than the various sorbent systems. The adsorbent is charged and passed through the adsorption chamber to equilibrate with the particular desorbent. At any time, the petrochemical complex containing indene is injected for several minutes. The desorbent is reflowed and the indene and other components are eluted as in a liquid-high chromatography operation. Emissions are analyzed for the stream, or release samples are collected periodically and then analyzed by envelope tracking and analysis of developed peaks of the same component.

From the information derived from this test, the performance of the desorbent is evaluated according to the void volume, the retention volume for the extract or the residual component, the selectivity for one of the many components and the desorption rate of the extract component by the desorbent. The retention volume of the extraction or weight component can be specified as the distance between the center of the peak envelope of the extraction or weight component and the center of the peak envelope at the point of comparison of the tracer component or other known ones, and also by the distance between the peak envelopes. It can be referred to as the volume (cm 3) of the adsorbent pumped during this time interval appearing. The selectivity of the extract component relative to the weight component can be specified as the ratio of the distance between the extract component peak envelope and the tracer peak envelope (or other comparison point): the same distance between the weight component peak envelope and the tracer peak envelope. The exchange rate of adsorbent and extract component can be specified as the distance between the centers of the peak envelopes in help intensity. The narrower the peak width, the faster the desorption rate. The adsorption rate can be specified by the distance between the tracer peak centers and the disappearance of the extracted components immediately desorbed. This distance is again the volume of desorbent pumped during this time interval.

The following examples are described to demonstrate the selectivity relationship for carrying out the method of the present invention. This embodiment is not limited to this.

Example I

The purpose of this example is to provide the above-mentioned pulse test when using sufficient pressure to maintain a liquid phase with toluene as desorbent to separate and recover indene from sodium-exchanged zeolite and indene containing petrochemical complex at 120 ° C. To show the results of the pulse test obtained from the device.

Naphtha cracker cracked oil can be obtained with the following suitable compositions:

Examples of the C ₈ -C ₁₀ alkyl aromatics include trimethylbenzenes such as pseudocumene and hemimelytin, indane, diethylbenzene, propyltoluene and ethyldimethylbenzine. Unsaturated alkyl aromatics include styrene, vinyltoluene isomers, alpha and betamethylstyrene and propenyl toluene isomers. 90% of these materials boil in the range of 132-208 ° C.

This material is vacuum fractioned in a Hypercal distillation tube to yield an intermediate fraction rich in indene. Intermediate fraction gas chromatography / mass spectroscopy (GC / MS) analysis provides a suitable composition:

Alkyl aromatics contained in the indene rich intermediate fractions include trimethylbenzene, diethylbenzene, ethyldimethylbenzene and propyltoluene. Unsaturated alkyl aromatics include propenyl toluene and methylstyrene, of which 95% is boiled in the range of 165-196 ° C.

1 cc of indene-rich naphtha cracker cracked oil intermediate fraction, 1 cc of toluene and 0.25 cc of n-heptane tracer were introduced into a pulse test tube at 120 ° C. and filled with a NaX adsorbent having a water content of 4.84 wt% based on zeolite. do. Toluene is used as the desorbent at a flow rate of 1.2 cc / min.

1 is an experimental result of observing the separation of the groups. The analysis indicates that the minimal adsorption group of the feed consists of alkylbenzene and toluene containing ethyl and propyl groups such as diethylbenzene and propyl toluene and the like. The second group has a long retention on the adsorbent and consists of methylstyrene such as trimethylbenzene such as pseudocumen, beta methylstyrene, and other components of similar structure and functionality. The third group of compounds has a long retention volume and consists mainly of C ₁₀ unsaturated alkyl aromatics such as propenyl toluene isomers. After all, indene is the most strongly adsorbed material in the feed pulse mixture.

From the curve of relative concentration (by area chromatography of gas chromatography) versus retention volume (RV) in ml in FIG. 1a, the selectivity of indene can be calculated for compounds of various weight groups:

The effect of the adsorbate content can be observed by repeating the experiment of Example 1 using an adsorbent while varying the weight percent of water based on the zeolite content. FIG. 1b shows the curve of component total retention volume (NRV) versus zeolite weight%. It has been observed that the separation and recovery of indenes gives satisfactory results over the entire range of zeolite water content, while increasing the selectivity as molar concentration is reduced and the indenes and component groups 2 and 3 as a whole are increased. The increase in total implies a longer desorption time, so the two factors must be balanced by optimal economic manipulation.

Example II

The pulse test of Example I is repeated except that 6.14% by weight of water, based on the zeolite content, is present in the adsorbent and the desorbent material is benzene. 2 shows the results, the selectivity is recorded in the table below.

Example III

The pulse experiment of Example I is repeated except that the NaX adsorbent contains about 1.5% by weight of water and the desorbent is fluorobenzene. The results are reported in FIG. 3 and the table below.

Example IV

The pulse experiment of Example I is repeated except that the adsorbent is NaY zeolite containing about 0.06% by weight of water and the temperature is 60 ° C. The results are reported in FIG. 4 and in the table below, indicating that the compounds of groups 2 and 3 are much more similar in terms of separation behavior than with NaX adsorbents.

Example V

The pulse experiment of Example I is repeated except that the adsorbent is K-X zeolite containing about 1.5% by weight of water and the temperature is 60 ° C. The results of the experiments are reported in FIG. 5 and in the table below, indicating that indenes are separated from the unsaturated and aromatic alkyl groups of groups 1 and 2 and from the strongly maintained unsaturated alkyl aromatics of group 3. It is obvious.

Example VI

The pulse experiment of Example I is repeated except that the adsorbent is potassium-exchanged Y zeolite containing about 1% by weight of water and the temperature is 60 ° C. The results of this experiment are reported in FIG. 6 and the following table, and from these results it is clear that indene separates from alkyl aromatics and unsaturated alkyl aromatics, although it is not clearer than the above-mentioned examples:

EXAMPLE VII

NaX zeolite contains about 7.5% water by weight and consists of 20% by volume indane, indene and 1,2,4-trimethylbenzene, 10% by volume nC ₇ tracer and 30% by volume toluene The pulse experiment of Example I is repeated except that it is 60 ° C. The results of this experiment are shown in the following table and in FIG. 7, from which the synthetic preparation of indene synthesizes indene via dehydrogenation from hydrocarbon precursors and / or dehydrogenation from hydrocarbon precursors and / or cyclization reactions. It can be seen that indene can simply be separated from the alkyl aromatic mixture occurring in the process:

EXAMPLE VII

This embodiment, as a preferred type, employs the operation of a continuous simulated mobile phase backflow form, and is known as a pilot plant scale known as carousel units as detailed in US Pat. No. 3,706,812 (de Rosset et al). Illustrate the fairness, including the test apparatus of. For simplicity, the device consists mainly of 24 series of connected adsorption chambers, each about 44 cc in volume. The total chamber volume of the device is about 1.056 cc. Each suction chamber is connected to each other in series by a relatively small diameter connection tube, which is connected by a rotary valve. The valve has an inlet and an outlet for introducing the raw material and the desorbent into the chamber and extracting the extract tailings stream from the chamber. Simulated backflow is achieved by operating a rotary valve and maintaining a predetermined pressure differential and flow rate through various lines passing through a series of chambers. The adsorbent remains stationary when the fluid flow is a stable countercurrent flow through a series of connecting chambers when viewed at any location within the adsorption chamber. The movement of the rotary valve is done in a periodic potential manner so that new manipulation can take place on the adsorption bed located between the active inlet and outlet of the rotary valve. Inlet and outlet lines are connected to the rotary valve. The rotary valve includes a feed inlet line through which the feed mixture passes and a desorbent, that is, an extract stream discharge line through which toluene is mixed with indene and an extract tailings stream discharge line through which it is mixed with the desorbent. In addition, the jet inlet line is used for the purpose of ejecting the raw material component from the line which will already contain the raw material and subsequently will contain the extraction tailings or extract stream. The eruption used is toluene, which remains in the device as part of the extract stream and the tailings stream.

Details of additional devices can be found in US Pat. No. 3,706,812. For greater understanding, the manipulations that occur within the device are described in US Pat. No. 2,985,589 to DBBroughton and "The Separation of P-xylene from C ₈ Hydrocabon Mixtures by the Parex Process" (May 17, 1970, 20). By the American Institute of Chemical Engineers' Third Federation Banquet held in San Juan, Puerto Rico).

This document describes in detail the basic operation that has taken place in the test apparatus used in this type, although the document relates to hydrocarbon separation, the test apparatus itself is perfectly suitable for this type.

The raw material mixture of the device is a fractionated heavy naphtha cracker pyrolysis oil containing 70.5% indene.

The adsorbent used is the sodium-exchanged Y faujasite of Example IV.

Desorbent is toluene.

The operating parameters in carousel units are as follows:

1. A / F = 3, where A is the selective feed volume of adsorbent in cc and F is the raw material ratio for the separation step in cc / hr.

2. Process temperature = 60 ℃

3. Valve cycle time = 60 minutes

Several experiments, each for 6 hours, were performed on carousel units. In these experiments, it was observed that indene was adsorbed and separated to form an extract, and alkyl and unsaturated alkyl aromatics were relatively non-adsorbed and separated to become extraction tailings.

In these experiments, the extract and extract tailings streams were analyzed for their component concentrations. The results of these experiments can be plotted as a curve of indene extraction purity versus indene recovery and are presented in FIG. The best separation effect obtained was 95.4% indene purity at 99% recovery. Thus, it becomes clear that with the use of NaY adsorbents, indenes can be separated from complex petrochemical mixtures containing alkyl aromatics, unsaturated alkyl aromatics and indenes.

The water content (% by weight) of zrolie used here is measured by the LOI method (ignition loss at 300 ° C.).

Claims (8)

In order to separate indene from a feed mixture containing an alkyl aromatic material, an unsaturated alkyl-substituted aromatic material and indene, the feed mixture is contacted with an X- or Y-type zeolite substituted with sodium or potassium under adsorption conditions. Recovering indene from the resulting indene-containing zeolite by selectively adsorbing indene and then desorbing under desorption conditions with a desorbent selected from the group consisting of benzene, halogen- and / or alkyl substituted monocyclic aromatics and mixtures thereof. Separation method of indene. The method of claim 1 wherein the zeolite has a water content of 8% by weight (LOI) or less. The method of claim 2 wherein said water content is 4-7%. The process of claim 1 wherein said feed mixture is distilled petroleum chemical to obtain an intermediate fraction having an indene concentration of 30-80% by weight. The method of claim 1 wherein the concentration of indene in the feed mixture is 35% by weight or less. The method of claim 1, wherein said feed incidentally contains indan. The method of claim 1 wherein said desorbent is toluene. The method of claim 1 wherein said desorbent is fluorobenzene.

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