The way the carbon skeleton isomerization of olefins (options)
(57) Abstract:Usage: petrochemistry. Essence: the isomerization of C4-C15olefins carried out through interaction of C4-C15olefins having a first skeletal distribution, with aromatic compounds in the alkylation conditions to obtain the alkylated aromatic product, dealkylation of alkylated aromatic product dealkylation or get dialkylamino product containing these aromatic compounds and olefins corresponding to the olefins in the alkylation and having a second skeletal distribution different from the first skeletal distribution. In the alkylation and dialkylamino used acid catalysts, such as molecular sieves. The reaction can be carried out in reactors of a straight-flow type fixed bed, or in reactors for catalytic distillation. Effect: improved isomerization selectivity and facilitate separation of the products. 2 C. and 31 C.p. f-crystals, 4 tab., 4 Il. The technical scope of the invention
The invention relates to a method of the carbon skeleton isomerization of olefins. More specifically, red olefins (also referred to in this description isorevenue or tertiary olefins) and separation of olefins from paraffins.Art
The carbon skeleton isomerization of olefins is an important reaction for the fuel and chemical industries. For example, the isomerization of n-butene to isobutene and n-pentanol in isoamylene was carried out to obtain isoolefine. Since n-pentane have a lower octane number than isopentane, isomerization of n-pentanol is useful for the production of motor fuel. Isomerization of n-butenes and n-pentanol in isoolefine used to obtain oxygenates such as methyl tert-butyl ether (MTBE) and tert-amylotrophic ether (TAME), is increasingly important to obtain the composition of the reforming of gasoline (RFG). Ethers are used as additives for improving the octane number of gasoline, and to reduce undesirable emissions.Currently, there is no simple technology selection olefins from paraffins and conversion of linear olefins to branched olefins. Therefore, isoolefine high purity (primarily tertiary olefins) were received, mainly the allocation of tertiary olefins from a mixture of olefins using the process of cold acid, extraction with sulfuric acid, however, sulfuric acid standard processes is usually SS="ptx2">In U.S. Patent 3121124 (Shell) describes the destruction of the tertiary olefins from a mixed flows through esterification and simple decomposition of the ether with the release of the tertiary olefin is essentially in pure form. Other methods, using the decomposition of the ethers described in U.S. Patent 4447668 (CR& L); 4551567 (CR&L), 4691073 (Exxon). However, in these processes the linear olefins are essentially not subject to change, and the main result is the allocation of isoolefine of paraffins and linear olefins. The selection of linear olefins in the form of isoolefine limited, since they are usually present when there is too much dilution (in low concentrations), for which there is no available technology, cost-effective conversion of linear olefins in isoolefine.Standard isomerization of olefins with a co-current fixed bed of catalyst is limited by equilibrium, thus practically limiting the achievable yield of olefins. The isomerization is carried out with the use of acid catalysts, such as molecular sieves, etc.The carbon skeleton isomerization is carried out with acid catalysts, such as fluorinated alumina, SAPO (silicoaluminate), ALPO (aluminophosphate selective zeolite catalysts for skeletal isomerization of n-butene to isobutene. The most preferred method of carrying out the isomerization is a vapor-phase process with a fixed bed of catalyst, in which a tubular reactor filled heterogeneous acid catalysts and a pair of source material olefinic hydrocarbon is passed through the catalyst bed at temperatures which are effective for the isomerization of the carbon skeleton. Usually the double bond isomerization of olefins is much easier than for skeletal isomerization, and therefore, the temperature required for the isomerization of double bonds, are much lower temperatures isomerization of the skeleton.Changing skeleton alkyl groups of alkylaromatic compounds, such as bucilina group butylbenzene, is a different kind of isomerization, which is different from the olefin isomerization. R. M. Roberts and co-authors (JACS Vol. 81, 640, 1959) explained the structural isomerization between second-utilname and isobutylene groups without interrupting butilkoi group from the benzene ring. Interconversion among second-butylbenzene, isobutylbenzene and tert-butylbenzene shown by reactions catalyzed by acid. The composition of the equilibrium mixture contains only a small amount of tert-butylbenzoyl proceeds through the formation of pairs of intermediate products, bonded composite intermediate product, which is first formed in the interaction of alkylaromatic compounds with acidic center on the catalyst, and then turns into a complex intermediate compound with a methyl bridge.The catalyst used in the standard process of the carbon skeleton isomerization of olefins, typically undergoes relatively rapid catalyst deactivation caused by the deposition of heavy carbon compound (coke) on the surface and in the pores of the catalyst. Thus, regardless of the types of catalysts, there is always a quick initial deactivation of the catalysts. Due to this rapid initial deactivation of the catalyst and other competing reactions isomerization of the skeleton becomes impractical at temperatures below approximately 350oC. Because the original materials of olefinic hydrocarbons in addition to olefins usually contain a small amount of dienes and alkynes, deactivation of the catalyst becomes even faster. Therefore, the need for frequent regeneration of the catalyst. To overcome the lower reaction rate of the isomerization reaction temperature should be increased. This can lead to the more light products, than anticipated. Therefore, it becomes necessary regeneration of the catalyst or replace the deactivated catalyst with fresh catalyst. In fact, the duration of the regeneration cycle of the catalyst is often one of the main factors that determine is whether the process is commercially successful or not. Alkylation of aromatic compounds with olefins is widely used in practice for various products of alkyl and can be achieved using various acid catalysts. Zeolite catalysts are known to be the best for this purpose, see , for example, U.S. Patents 4169111 (Unocal); 4301310 (Mobile); 4798816 (Unocal); 4876408 (Unocal); 4891458 (Chevron); 4849569 (CR&L)); 5446223 (CR& L).Dealkylation well described. In publication I. Takahashi et al., Kinetics & Catalysts (IV) 291 described conducting vapor dealkylation of tert-butylamine compounds, such as tert-butylbenzoyl, p-tert-butyltoluene and p-tert-mutilative over silica-alumina catalyst. Tert-butyltoluene was deelkraal over Y-zeolite catalyst. Reactivity to dialkylamino three butylbenzene isomers over the catalysts of the silica-oxide luminiare-, second - and n-butylbenzoyl. Dealkylation of tert-butylbenzene at a temperature of 180-360oWith results in only the isobutylene as olefin product.For dealkylation of second-butylbenzene proposed two different mechanisms; one for temperatures below 400oWith, and the other for temperatures above 400oC. Olefinic products of dealkylation at temperatures below 400oWith contain small amounts of isobutylene. C. Farcasiu (J. Org. Chem., Vol. 44, 13, 1979) investigated the acid-catalyzed dealkylation alkylbenzene compounds, such as toluene, ethylbenzene, isopropylbenzene and tert-butylbenzoyl. Dealkylation of alkylaromatic compounds, as suggested, flows through the successive formation of two intermediates. The first intermediate product (phenyl cations with delocalized charge) is formed by protonation of the benzene ring of alkylaromatic compounds. This intermediate compound is decomposed with the formation of benzene and alkyl Carbonia-ion battery (the second intermediate product). This second intermediate product decomposes to olefin product from the isomerization of the carbon skeleton or without it. The first intermediate about verbatim-benzene and isobutylbenzene. Publications R. M. Roberts, and D. Farcasiu, mentioned above, can explain the reaction mechanisms including the conversion of linear olefins in isoolefine through consecutive reactions alkylation/dealkylation described in this invention.In U.S. Patent 4499321 describes the process of selective dealkylation 1, 4-dialkylphenol from mixtures of dialkylphenol using catalysts based on molecular sieves. This method is useful for obtaining m - and p-Cresols. A mixture of m - and p-Cresols alkylate the isobutylene from a mixture of isomers of tert-butylketone that separate by distillation. Separated isomers dealkylase obtaining m - and p-Cresols.In the publication M. Miranda, Hydrocarbon Processing, pages 51-52, August 1987, describes a method of separating pure isobutene from C4-mixtures by selective alkylation of phenol with isobutylene and dealkylation selection of isobutylene.Revealed that many types of processes described above are suitable for catalytic reactions distillation. In catalytic distillation or reactive distillation components of the reaction system can simultaneously be separated by distillation with the use of catalytically who (CR&L); 4242530 (CR&L); 4250052 (CR&L); 4302356 (CR& L) and 4307254 (CR&L).The present invention provides a method of separating olefins from paraffins. The advantage of this method is that dealkylation alkylated aromatic product provides the required mixture of olefin isomers, which are easily separated from the aromatic compounds. This advantage arises from the significant differences in the boiling points of olefins and aromatic compounds.In the prior art there is no disclosure of the carbon skeleton isomerization of olefins by alkylation and dealkylation of aromatic compounds. The interaction of olefins with aromatic compounds in the presence of paraffins, Department of alkylated product, dealkylation of the alkylated product and the allocation of skeletal isomerized olefins are not described in the prior art.BRIEF DESCRIPTION OF THE INVENTION
In a broad sense the invention is a method of isomerization of the carbon skeleton of olefins for C4-C15olefins by reaction of at least one4-C15olefins having a first skeletal distribution, with aromatic compounds these aromatic product in the dealkylation conditions to obtain dialkylamino product, containing these aromatic compounds and olefins, which correspond to the olefins in the alkylation and have a second skeletal distribution, different from the first skeletal distribution. Olefins fed to stage alkylation, isomerized in the process of alkylation/dealkylation.The term "skeletal distribution" means the relative composition of branched and linear isomers of this olefin. For example, C4supplied to the alkylation reaction, can only contain butene-1 and butene-2, therefore, his skeletal distribution is 0% branched olefins and 100% linear olefins, and after dealkylation - 50% tert-butylene, and the rest is butene-1 and butene-2, therefore, skeletal distribution deaccelerating olefins is 50% extensive and 50% linear.The alkylation reaction is preferably carried out under conditions that allow to achieve essentially 100% conversion of the olefins present. Because olefins are usually present as part of the aliphatic stream containing paraffins and olefins, alkylation is also used for the separation of alkenes from the rest of the stream. During phase alkylation alkylated aromatic with what edeline alkyl groups depending on the temperature of the alkylation, even if the feedstock contains only linear olefins.Acid catalysts are used at the stage of alkylation and dealkylation stage. Molecular sieves are preferred catalysts for both reactions, and more preferred zeolites.Aromatic compounds with stage dealkylation can be separated and recycled to the alkylation plant to repeat the process. Can be similarly selected linear olefins and recycled either in the reaction of alkylation or dealkylation reaction. One way of marking the tert-olefins that contain part of isoolefine, and separation of these tert-olefins of the olefin mixture is the contacting of a mixture of olefins with1-C8alcohol for the selective interaction of the tert-olefins with the formation of ethers, as described above. Unreacted olefins from the reaction can be easily separated from the ethers for recycle to the alkylation reaction or other applications.The reaction of alkylation and dealkylation may, either one, or both, to be conducted in a continuous reactor with a fixed catalyst or reactor catalytically alumina and molecular sieves, including zeolites. Dealkylation of alkylation can be carried out using the same or similar catalyst, the alkylation, that is, an acid catalyst, such as zeolite. The dealkylation conditions are more stringent than the conditions of alkylation, but in both reactions may to some extent be a backlash.Therefore, the reactions carried out using catalytic distillation are predominant, because the reaction products simultaneously separated from the inert components, and distillation can be carried out with holding the reagent materials inside structural layer of catalytic distillation (in the case of the alkylation of aromatic compound remain in the zone of the catalyst and the alkylation product is removed, in the case of dealkylation product alkylate petrol kept in the zone of the catalyst, and aromatics and olefins are removed).In one embodiment the reaction of alkylation of aromatic compounds is carried out in the reactor of the catalytic distillation using raw material that contains paraffins, linear olefins and/or branched olefins, and the zeolite catalyst, where a portion of the olefins to approximately 100% conversion of the olefin is x compounds are separated from the alkyl products by distillation in the distillation reactor. The separated mixture consisting of alkyl aromatics and parts of aromatic compounds, is passed through the dealkylation reactor with a fixed catalyst bed for receiving the branched olefins. The concentration of branched olefins in the olefinic product is equal to or greater than the concentration in normal olefin isomerization.In another embodiment dealkylation of tert-alkylaromatic compounds is carried out in a reactor with a fixed catalyst bed. When the temperature dealkylation is relatively low olefin product consists mainly of branched olefin, which indicates the presence of a small isomerization of branched olefins in the linear olefin or skeletal rearrangement of tert-alkyl groups of the original alkylaromatic compounds in a linear alkyl group. However, when the dealkylation temperature rises, the content of linear olefins in the olefinic product steadily increased, indicating increased skeletal isomerization tert-olefins in the linear olefin and a skeletal isomerization tert-alkyl group, a linear alkyl group.Idealgranny material predpochtu and returned to the alkylation zone.BRIEF DESCRIPTION OF FIGURES
Fig. 1 is a schematic representation of one embodiment of a process of alkylation, dealkylation and allocation of olefins.Fig. 2 is a schematic representation of one embodiment of the selective interaction of the tert-olefins and subsequent alkylation/dialkylammonium.Fig.3 is a schematic representation of one embodiment of alkylation, dealkylation and highlight isoolefine by selective esterification of isoolefine.Fig. 4 is a process flow diagram of the present invention the separation of isoolefine.DETAILED DESCRIPTION OF THE INVENTION
The olefins preferably represent FROM4-C10olefins, more preferably C4-C8olefins, including both normal and isomeric forms. For example, suitable olefins are butenes, isobutene, 1-penten, 1-hexene, 2-hexene, 2,3-dimethyl-1-penten, 1-octene, 1-nonen and 1-mission dodecene, etc., As described above, in the special case used raw materials with a high content of linear olefins which undergo isomerization during the process in the corresponding isomeric form.Aromaticity distillation reactor column type. Organic aromatic compounds include hydrocarbons, one or more cycles containing from 6 to 20 carbon atoms, which may contain substituents that do not affect the alkylation, including halogen (Cl, Br, F and I), HE, and alkyl, cycloalkyl, kalkilya and alkaline group containing from 1 to 10 carbon atoms. Suitable organic aromatic compounds include benzene, xylene, toluene, phenol, cresol, ethylbenzene, diethylbenzene, naphthalene, inden, phenylpropyl, 1,2-dihydronaphthalene etc. , a preferred group of compounds for use in this method include benzene, xylene, toluene, phenol and cresol. A preferred group of compounds for use in this way represents a benzene, xylene and toluene. A mixture of aromatic compounds and mixtures of olefins can be used as raw materials for this method may represent a relatively pure streams of each of them, or both.Alkilirovanny
In the molar ratio of alkylation of organic aromatic compounds and olefin may be in the range from 1:1 to 100:3, preferably from 2:1 to 50:1 and more preferably from about 2:1 to 10:1.The reaction of alkylation of Olite, ferrierite (ferrierite, mordenite, ZSM-5, ZSM-11, phosphoric acid media (SPA), resin acid, etc.Dealkylation
Dealkylation of alkyl products can be carried out in the presence of acid catalysts. The preferred catalysts are molecular sieves, purified natural acid clay and amorphous aluminosilicates. Preferred catalysts molecular sieves are one-dimensional, two-dimensional or three-dimensional sieves with pore size from medium to large (from 3.50 and preferably from 3.5 to such as ferrierite, SAPO-11, SAPO-35, ZSM-5, ZSM-22, ZSM-23, ZSM-57, zeolite beta, pentasil-zeolite (pentasil zeolite and zeolite Y.The dealkylation can be carried out in the vapor phase or in the presence of both vapor and liquid with the use of a reactor with a fixed catalyst bed and reactor catalytic distillation column type. The raw material for feed to the reactor dealkylation can be a pure alkylates, or a mixture of alkylates, and aromatic compounds such as benzene, toluene and xylene or paraffins. Because the dealkylation reaction is an endothermic reaction, diluted alkylates are desirable to achieve high coactor, such as reactors with heat exchange with the tube sheet or plate. The dealkylation products are olefins and aromatic compounds. Olefinic products from the stage dealkylation consist of olefin isomers, of which tert-olefins can be selectively interact with alcohols, water, carboxylic acids or aromatic compounds. Other linear olefins are returned either in the reactor alkylation or dealkylation reactor for conversion to tert-olefins.The temperature interval for the dealkylation is from 180 to 550oC, preferably from 200 to 450oC. Typically, a lower pressure is favorable for the dealkylation reaction. Interval pressure is less than atmospheric to 350 f/square D. (2408 kPa), preferably from atmospheric to 150 F. per square D. (1032 kPa).Alkylaromatic compound may be pure or a mixture of different aromatic or paraffinic compounds. Depending on the components in mixtures alkylaromatics connections, choice of catalyst and operating conditions, olefinic products are pure or essentially pure tert-olefins, essentially pure linear olefins and the pressure from atmospheric to high for example, from 1 to 40 atmospheres. In the distillation column reactor temperature will vary depending on the local composition, i.e. the composition at any given point along the column. In addition, the temperature along the column will be, as in any distillation column, the highest temperature will be in the lower part of the column, and the temperature along the column will be the boiling point of the compositions at a given point in the column under specific conditions of pressure. In addition, the exothermic heat of reaction does not change the temperature in the column, but just causing more boils. However, the temperature inside the column taking into account the above considerations will usually be in the range of 50oWith the critical temperature of the mixture, preferably from 70 to 300oWith at pressures from 1 to 20 atmospheres.If raw materials for the dealkylation consists of various alkylaromatic compounds, the alkyl groups of which consist of tert-, sec-, ISO - and n-alkyl groups, dealkylation can be carried out selectively or selectivity depending on the purpose dealkylation or application of olefin products. For this catalyst the lower temperature used for the selective dealkilirovanie for selective dealkylation getting mixed olefinic products, containing various olefinic isomers. For example, if part of alkylaromatic compounds consists of compounds containing tert-alkyl groups, pure or essentially pure tert-olefins can be obtained by carrying out the dealkylation at lower temperatures. It is important that dealkylation was not carried out at too high temperatures, since the olefinic product will contain linear olefins due to skeletal rearrangement of some of the tert-olefins products or tert-alkyl group of alkylaromatic compounds. Dealkylation other neprivrednih alkylaromatic compounds at higher temperatures results in a mixed olefin product of olefin isomers, whose composition is close to the equilibrium distribution. The optimum temperature for dealkylation depend on the alkyl groups in the alkylate and the used catalyst. For example, when the catalyst dealkylation of tert-butyltoluene apply ferrierite molecular sieves, it is desirable to dealkylation at temperatures below approximately 570oF (299oC). For a given acid catalyst tert-alkylaromatic compound is Tert-alkylaromatic compounds can be dealkylase over weakly acidic catalysts.Publications R. M. Roberts, and D. Farcasiu, discussed above, can be assumed mechanisms of reactions included in the conversion of linear olefins in isoolefine through consecutive reactions of alkylation-dealkylation disclosed in this invention. These sequential reactions can be conducted in one stage or in two stages. If the alkylation is carried out at higher temperatures and low pressures, as alkylation and dealkylation and isomerization of olefins can run concurrently in the catalytic reaction zone, leading to the obtaining of olefin isomers in the reaction products in a single phase. However, if the alkylation reaction is carried out at a lower temperature and high pressure and dealkylation is carried out at a higher temperature and lower pressure, the same result can be obtained in two stages.Products from the stage dealkylation are mixtures of isoolefine and linear olefins, of which isoolefine (branched olefins can be separated from linear olefins using existing technologies, such as the extractive distillate or selective reaction such as esterification. In the method of selective reaction compartment soulsnatcher less reactive, than linear olefins, isoolefine in mixtures can selectively interact with alcohols, water, carboxylic acids and aromatic compounds, after which the unreacted linear olefins are separated from the more high-boiling reaction products by simple distillation. Selected linear olefins back to the alkylation reactor.When as agent for the selective reaction of isoolefine used alcohol, such as methanol or ethanol, the reaction product is a simple ether such as methyl tert-butyl ether or ethyl tert-butyl ether. These ethers are valuable products, they are used for blending components as oxygenates and octane component for the reforming of gasoline. If the target products are isoolefine, these ethers dealkiller in isoolefine and alcohols, and isoolefine separated from the alcohols by simple distillation. Therefore, this invention provides means for the conversion of olefinic components with low RON in mixtures of the components with high RON, as well as in the components of gasoline with less than a high vapor pressure. It is desirable to reduce the content of olefins and aromatics in gasoline by e the goal. Therefore, this invention offers a useful technology for MTBE or TAME from a mixed olefin streams.When as agents for selective reaction with isorevenue are aromatic compounds such as benzene, toluene, xylenes or phenols, the reaction products are tert-alkylaromatic compounds. When the target products are isoolefine, these tert-alkylaromatic compounds dealkiller in the presence of acid catalysts. It is important that dealkylation was not carried out at too high temperatures. If the dealkylation temperature is too high, olefinic product will contain linear olefins.If the alkyl group of alkylaromatic compounds consist of linear alkyl groups and target products are linear olefins, dealkylation is carried out at the lowest possible temperature, using a weaker acid catalyst.Direct-flow reactor
For once-through alkylation fixed bed catalyst for olefinic and aromatic raw materials before entering into the catalytic reaction zone are pre-mixed. Another method of holding such acceleratedby portion served in the alkylation reactor at different points, when the aromatic feedstock is passed through a reactor with a fixed catalyst bed. For this operation with a fixed bed of the catalyst flowing from the reactor stream can be recycled to improve selectivity and reduce the heat of reaction, since the alkylation reaction is exothermic. The preferred temperature interval alkylation is from 50 to 500oC, preferably from 80 to 300oC. the pressure in the alkylation reactor should be high enough fraction of aromatic compounds could be in liquid form. Therefore, the pressure in the reactor alkylation depends on the temperature and composition of the feedstock in the reactor.The reactor distillation column type
When the alkylation is carried out using the reactor of the catalytic distillation in the distillation column load of acid catalysts; and light olefins, such as C4or C5the olefins may be introduced into the distillation column at the bottom section of the column, and aromatic compounds such as toluene or xylene, can be introduced into the distillation column in the top section; or as olefins and aromatic compounds are introduced in the lower section is alkilirovanija and separation of paraffins from aromatics or aromatic compounds from alkyl products. Unreacted paraffins in the olefin-containing raw material is separated from the reaction mixture as the top product, and alkylates (alkylated products) and possibly some of the aromatic compounds is removed from the bottom of the column as the cubic product. If necessary, you can delete some of the aromatic compounds in the form of the upper shoulder strap with paraffin.After dealkylation of alkyl products, olefins, and aromatic compounds are removed from the column as the top product, and unreacted alkylates isolated in the form of the cubic product to return to the top of the catalyst. The required conversion on the passage is from 10 to 100%, preferably from 30 to 80%.When dealkylation is carried out with the use of the reactor of the catalytic distillation column type, the pressure in the column must be high enough, at least part of the raw material was in liquid form. Olefinic products are removed from the catalytic reaction zone in the form of the top ring. Neprevyshenie alkylates are removed from the bottom of the column and recycled to the top of the catalyst.When the alkylation is carried out by way catalytic distillation, the exact location BBO is avago product. In one embodiment the feed olefins in the reactor is preferably carried out below the catalyst bed, thereby allowing the reagents to be mixed prior to contact with the catalyst bed. In another embodiment of the olefinic feedstock is fed into the reactor preferably above the catalyst bed.Aromatic raw materials can be added at any point in the reactor distillation column type, but preferably it is added below the fixed catalyst layer or the phlegm in the form of the composition, depending on its boiling point. Preferred large excess of aromatic compounds relative to the olefin in the reactor in the range from 2 to 100 mol of aromatic compound per mole of olefin, i.e. the net molar ratio in the raw material aromatic compounds of olefin may be close to 1:1, although the system catalytic distillation operates so as to maintain in the reaction zone a substantial molar excess of aromatic compounds relative to the olefin. Alkilirovanny product is the high-boiling product and is separated in the lower portion of the column is usually in the form of the cubic product. Organic aromatic compound may be the second most high-boiling components is of such compounds require a very high reflux ratio in the column and the low productivity of the plant. Therefore, the exact ratio of the aromatic compound and the olefin must be determined for each combination of reagents and acceptable content, olefin or in the upper chase, or the product of alkylation.The length of the catalyst layer in the column, especially the part where contact of the reagents and reaction takes place depends on the reagents, designated input olefinic feedstock and acceptable content unreacted olefin streams emanating from the column. Some testing will be required for each set of reagents and parameters of the purity of the stream below.The advantages of this alkylation carried out by way catalytic distillation, are the result of continuous flushing of coke or coke precursors on the catalyst surface, which leads to a much longer life of the catalyst, the natural separation of the products in the catalytic reaction zone, more sustainable flow of reactants to the catalytic reaction zone, the best transfer of materials between the bulk phase and the reaction zone, the best temperature control, called dynamic equilibrium vapor-liquid and best steam movement compared to traditional SP groups. For example, when n-butenes are olefins for alkylation, the alkyl groups in alkyl aromatic compounds are mainly second-butylene and tert-butylene group. The degree of isomerization of alkyl groups depends on the temperature. For example, if the alkylation is carried out at temperatures lower than approximately 400oF (204oC) using catalysts molecular sieves, the alkylation products contain a small amount of tert-Budilnik aromatic compounds. When using n-pentane, alkyl groups are isomers WITH5such as second-pentyl, 3-methylbutyl, tert-amyl, etc. If alkylation is used mixed C5stream, such as TAME raffinate, paraffin components in the mixed raw materials can be easily separated from the alkylate and can serve as a feedstock for steam crusher upon receipt of ethylene or in the skeletal isomerization of paraffins, because it contains small amounts of olefins, or does not contain them.In some reactions in the reactor distillation column type olefin will be more high-boiling material than aromatic hydrocarbons, for example, WITH8+ olefins. In the same is the product of alkylation, although lateral stretching can be used to reduce the content of such material in the product to an insignificant level. However, carrying out the reaction in a less than stoichiometric amount of olefin in the reaction zone, as described, is usually to maintain a low level of olefin as residue or completely eliminate it.Catalysts
Molecular sieves are porous crystalline aluminosilicate materials. Zeolites are one of the typical examples, which consist of atoms of silicon and aluminum, each of which is surrounded by four atoms of oxygen to form a small pyramid or tetrahedron (tetrahedral coordination). The term "molecular sieve" can be applied to natural and synthetic zeolites. Natural zeolites have uniform pore size and usually not considered as equivalent synthetic zeolites. In this invention, however, natural zeolites are acceptable to the extent that they are essentially pure. The focus of this discussion should be directed to synthetic zeolites, natural zeolites are treated as cash equivalents, as stated you the litas.Specific molecular sieves or other catalysts can be used by enclosing them in a porous container, such as cloth, sieve wire or polymeric mesh for use in catalytic distillation. The material used for the manufacture of the container, must be inert to the reagents and the conditions of the reaction system. Cloth can be any material which satisfies this requirement, such as cotton, fiberglass, polyester, nylon, etc. Sieve wire can be made of aluminum, steel, stainless steel, etc., Polymeric mesh may be of nylon, Teflon or similar Mesh or the number of threads per inch of the material used for the manufacture of the container is such that the catalyst remains in him and will not pass through the holes in the material. The containers can be used particle size of about 0.15 mm or powders and particles with a diameter up to approximately 1/4 inch (6.35 mm).The container used to hold the catalyst particles can have any configuration, such as pockets (bags), traditionally described in the referenced patents, above, or the container may be a single cylinder, spheres of the AET catalytic component. Each catalytic component is closely linked to the spatial component, which consists of at least 70% open space up to approximately 95% of open space. This component can be rigid or elastic, or have a combination of these properties. The combination of the catalytic component and a spatial component forms a catalytic distillation structure. The total amount of open space in the catalytic distillation structure should be at least 10% and preferably at least from 20 up to 65%. Therefore, preferably, the spatial component or material should be approximately 30% from the catalytic distillation structure, preferably from about 30 to 70%. Appropriate spatial material is stainless steel wire with knitted open mesh open mesh knitted stainless steel wire), usually known as dematera wire (demister wire or rolled aluminum. Other elastic components can be similar polymeric media with knitted open mesh of nylon, Teflon, etc., Other materials, such as silgosptehnika material with open structures, such as ceramiste or applied around the catalytic component. In the case of the use of catalytic components of larger size, such as tablets, spheres, pellets, etc., ranging in size from 1/4 to 1/2 inch (6.35 to 12.7 mm), each component of a larger size can be individually closely associated with or surrounded by a spatial component, as described above. Not essential that the spatial component completely covers the catalytic component. It is only necessary to have a spatial component, which is closely associated with the catalytic component, acted to separate the various catalytic components from each other, as described above. Therefore, the spatial component provides in fact the matrix is essentially open space, in which randomly, but essentially evenly distributed catalytic components.One catalytic distillation structure for use in this invention includes the placement of particles of molecular sieves in the many pockets in a cloth belt, which is supported in the distillation column reactor type with wire stainless steel knitted open mesh by twisting two grids together in spiral form. This allows you to get reeeally. Useful cotton or linen, but is preferred fabric of fiberglass.Fig. 4 illustrates one embodiment of the present invention, that is, the obtaining of high purity isobutene by alkylation of benzene Isobutanol from C4stream containing mainly n-butene, isobutene and C4alkanes. In accordance with Fig. 4, the reactor distillation column type 10 is divided into three sections. The middle section is placed catalytic nozzle (catalytic distillation structure 12, as described, using Y-zeolite ferrierite deposited in the pockets of the tape optical fiber, which is formed into a spiral with a grid of steel stainless steel, as described.The lower part of the column represents the standard configuration of the distillation column.Fresh benzene is conveniently served by the line 14. Registersee raw material 8 is mixed with benzene and is fed into the column through line 9 just below the packing of the catalyst 12 for better mixing. The reaction is exothermic and is initiated by contacting the two reactants in the catalytic nozzle. The alkylated products are more high-boiling than benzene and C4raw materials and are h the th excess benzene. Together with4alkanes and benzene other light fraction is distilled over as the top of the shoulder strap 20. The top zipper is held in the capacitor 22 to condense essentially all of the benzene, which passes through 24 in the collector 16 and therefore in the form of phlegmy through 26 in column 10. The benzene used in the reaction and lost with a light fractions, mainly C4alkanes (coming from the collector 16 through 28), supplemented with fresh benzene feedstock 14.VAT product that contains a mixture of benzene, alkylated by Isobutanol, and primary and secondary butylbenzene passes through 18 in the installation dealkylation 30, which represents a column of catalytic distillation and works for the simultaneous dealkylation of alkylate and separation into fractions of benzene and butenes in the form of the top ring 32 and heavy products form the cubic product 33. In this embodiment the benzene is separated from the olefin in the column 35 and return through 34 in substrate 14 in column 10. Olefins isolated in the form of the top ring 36.Fig. 1 is a flowsheet showing in graphical form the path of the reactants, products and by-products through any of several reactions, who is possessing the technological scheme, showing the separation of the unreacted olefin from the reaction of the tertiary olefins in accordance with this alkylation/dialkylammonium.Fig. 3 illustrates an embodiment of the present invention, that is, obtaining isobutene high purity by alkylation of toluene with Isobutanol from the stream WITH a4or5containing mainly n-butene, isobutene and C4alkanes or appropriate WITH5-primary and isoolefine. In accordance with Fig. 3 reactor distillation column type 110 with the middle section contains the catalytic nozzle (catalytic distillation patterns) 112, located as described, using etazolate deposited in the pockets of the ribbon of glass fibers and formed into a spiral with a stainless steel mesh, as described above.The lower part of the column represents the standard configuration of the distillation column. Fresh toluene is conveniently added through line 114. Registersee raw material 108 is mixed with recycle of toluene 154 and recycling 162, not containing souletin, and enters the column through 109 below the nozzle of the catalyst 112 for better mixing. The reaction is exothermic and is initiated by contacting two Rea is B> or C5raw materials and output via 118 in the form of the cubic product. Feed4or5is adjusted so that the reactor was a molar excess of toluene relative to the olefin. Apart FROM4or C5alkanes in the top of the shoulder strap 120 distilled off other light fractions with a certain amount of toluene. Upper shoulder strap 120 is fed to the condenser (not shown) to condense essentially all of toluene, which is returned to the column 110 as phlegmy.CBM product in the column 110 contains a mixture of alkylated toluene (olefins essentially 100% undergo conversion), which passes through 118 in the installation dealkylation 130, which is a once-through reactor with a fixed catalyst bed, working for simultaneous dealkylation of toluene alkylate. General dealkylation product passes through line 132 to a distillation column 140, where idealgranny material is separated and recycled through line 144 to the dealkylation reactor 130. Toluene and olefins display at the top of the shoulder strap through the line 142 to a distillation column 150, where the aromatic compound is isolated in the form of the cubic product through line 154 and recycle to the column Alki interact with alcohol, such as methanol, obtaining MTBE or TAME. Fresh olefinic feedstock may be added through line 156.Installing obtain ester can be any of the plants, which are known in this field. The system of this invention has a double advantage, when used in conjunction with the installation of receipt of the ether. First, because there is a conversion of linear olefins in isoolefine, the efficiency of the installation to obtain the ether is increased in two ways: first, the conversion of linear olefins in the fresh feedstock and conversion of recycled linear olefin plant for air in the system. The second advantage is the elimination of potential poisons the catalyst of esterification. For example, propionitrile, which is a poison accumulation for catalysts based resin acids used in the esterification, and dimethyl sulfide will either pass through the alkylation zone and go with alkanes or interact on the alkylation catalyst and removed in the regeneration process. Unreacted olefins from the broadcast settings can be recycled in the mixed olefin feedstock via line 162.Such standard elements as oborudovanie.EXAMPLES
4 lb (1,814 kg) commercial ferrierite catalyst in the form of 1/16 inch extrudate (1,587 mm) (P1) is placed in a tube with a diameter of 2.5 inches (63.5 mm). The length of the catalyst bed is 4 feet (1219,2 mm). Isomerization of the carbon skeleton of the n-pentanol mixed WITH5hydrocarbons (TAME raffinate) is carried out in conventional mode with a fixed catalyst bed, passing a couple of hydrocarbons over a catalyst in a downward direction. TAME raffinate comprises 4,56 wt.% WITH3-C4hydrocarbons, 32,14 wt.% n-pentanol, 4,36 wt. % isoamylene (2-methyl-2-butene and 2-methyl-1-butene), of 0.94 wt.% 3-methyl-1-butene, 50,27 wt. % isopentanol, 6,45 wt.% n-pentane, 1,28 wt.% +C6and other components. The results of isomerization at 41 hours of work are shown in Table 1.Control
Similar experiences in other conditions hold with other materials. Mixed C5the raw material consists of 1.29 wt.% WITH3-C4hydrocarbons, 66,04 wt.% n-pentanol, 9,86 wt.% isoamylene (2-methyl-2-butene and 2-methyl-1-butene), 2,87 wt.% 3-methyl-1-butene, 3,51 wt.% isopentanol, 14,63 wt.% n-pentane, 1,80 wt.% +C6and other components. The results of isomerization at 31 hours of work are shown in Table 1.Example 2
the tube diameter of 2.5 inches (63.5 mm). The length of the catalyst bed is 4 feet (1219,2 mm). The carbon skeleton isomerization of n-butenes in mixed WITH4hydrocarbons (raffinate 2) is conducted in the traditional mode of operation of the fixed catalyst layer, passing vapors of hydrocarbons over a catalyst in a downward direction. MTBE raffinate consists of 0.03 wt.% WITH3, with 4.64 wt.% isobutane, 22,85 wt.% n-butane, about 1.35 wt. % of isobutylene, 70,95 wt.% n-butenes, of 0.18 wt. +C5and other components. The results of isomerization at about 49 hours are shown in Table 3.Example 3
M-xylene alkylate using C5TAME the raffinate over the commercial catalyst is a zeolite Beta (6 g, 10-20 mesh, stainless steel tubing with a diameter of 0.5 inch (was 12.75 mm) and a length of 10 inches (254 mm)) at 420oF (216o(C) at a pressure of 100 lb/sq D. (688 kPa). Raw material obtained by mixing m-xylene with5TAME the raffinate to achieve a ratio of xylene/olefin equal 4,90. The composition TAME the raffinate: 0.07 wt.% WITH3hydrocarbons, 2,92 wt.% of butenes, of 0.54 wt.% butane, 33,33 wt.% n-pentanol, with 4.64 wt.% isoamylenes (2-methyl-2-butene and 2-methyl-1-butene), to 0.92 wt.% 3-methyl-1-butene, to 0.72 wt.% cyclopentene, 48,25 wt. % isopentane, 7,56 wt.% n-pentane and 1.05 wt.% WITH6+/unknown. The alkylation is carried out at 300-350the I of all olefins in the feedstock is from 97.7 to 100oC. Composite product from the reaction of alkylation of xylene mixed WITH5the olefins are concentrated by distillation of non-aromatic compounds and some of the excess xylene from obtaining raw materials for dealkylation. The composition of raw materials for dealkylation: 28,53 wt.% alkylate and 71,47 wt.% xylene. Five different commercial catalysts (6 g, 10-20 mesh) is loaded into a reactor made of stainless steel (diameter 0.5 inch (was 12.75 mm) and a length of 10 inches (254 mm) for dealkylation of the above raw materials. The results dealkylation are shown in Table 1.Example 4
Alkylation of toluene mixed flow C4hydrocarbons, make use of a reactor for catalytic distillation. The composition of the mixed stream WITH4hydrocarbons: 0,98 wt.% isobutane, 0,42% of isobutylene, 45,33% wt. n-butane, 31,98% TRANS-2-butene, 16,10% CIS-2-butene and 5,19% +C5. The height of the catalytic distillation column is 25 feet (7620 mm), the inner diameter of the column is 1 inch (25.4 mm). Commercial zeolite Beta (0,46 lb (0,209 kg) and extrudates 16 inches (406.4 mm)) was placed in a specially made permeable containers and load in the middle section of the distillation column. The length of the catalyst layer is 10 feet (3048 interval mode of operation of the catalytic distillation: column temperature 448-479oF (231,1-248,3oC), the upper pressure 245-270 f/square d, (1685,6-1857/6 kPa), average hourly feed rate 13-24. The molar ratio of toluene and olefin in the feedstock is in the range from 4.5 to 6.2. Paraffin components in raw materials, a very small amount of unreacted olefins and approximately 60-80% of unreacted toluene is removed from the upper part of the column as the top product. Alkylate petrol products, and about 20-40% of the rest of the unreacted toluene is removed from reboiler in the lower part of the column in the form of the cubic product. The results of alkylation are shown in Table 2. Composite product having the structure: 0,97 wt.% non-aromatic compounds, 36,93% of aromatic compounds (benzene, toluene and xylene), 61,86 wt.% various butyltoluene isomers (mono-, di - and tri-butyltoluene), of 0.42 wt.% heavy, dealkylase over various catalysts molecular sieves. Alkyl group butyltoluene formed lineinymi and branched utilname groups, but mainly second-butilkoi group. The results are shown in Table 3.Example 5
Dealkylation of tert-butyltoluene carried out with the use of raw materials, consisting of 64.5% of tert-butyltoluene and 35,41% toluene. Commercial length of 10 inches (25.4 mm) for dealkylation of this material. The results are shown in Table 4.Control experiments were performed for the carbon skeleton isomerization of linear olefins in the control example 1 and 2. When the isomerization is linear WITH4and C5olefins carried out in the vapor phase using commercial ferrierite catalyst in the traditional mode of operation of the fixed catalyst layer, there have been serious changes in activity and selectivity at the beginning of the interaction, as described in published articles and patents, due to the formation of coke on highly active centers. Isomerization of the carbon skeleton is linear WITH4and C5olefins became effective at a relatively high temperature, >750oF (>399oC).When the conversion of linear olefins in isoolefine conducted in accordance with this invention, there were significant differences in the reaction temperature from traditional vapor skeletal isomerization of olefins using a fixed catalyst layer, which allows the method in a wider range of temperature for this invention. This leads to a longer cycle of operation of the catalyst. Due to the cleansing action of the high-boiling aromatics is telesfora and pore cleaner for a longer period of time. Active centers and pores of the catalysts remain cleaner from the deposition of coke. Therefore, the catalysts were able to maintain high activity for a longer time.Suddenly, the dealkylation reaction of alkylates was effective at temperatures considerably lower than the temperature (<750F - 398,9oC) necessary for the skeletal isomerization of olefins during her using a fixed catalyst layer. The fact that the dealkylation reaction can be conducted at a temperature lower than the skeletal isomerization of olefins for this catalyst is very important to obtain isoolefine or derivative isoolefine. Since the equilibrium concentration of isoolefine decreases with temperature, the conversion of linear olefins in isoolefine conducted in accordance with this invention, leads to higher outputs isolation, as shown in Tables 1 and 3. The advantage of this invention compared to the traditional way of skeletal isomerization of olefins can be clearly presented. In this invention, not only the content isoretinoin components in the flow of product is higher the higher concentrations of olefins, that leads to the desired flows isoolefine for process downdraft. For example, upon receipt of ethers such as MTBE or TAME, can be obtained in higher yield of ethers to set this size. Linear olefins in the products can be turned into isoolefine after removal of isoolefine selective reaction of isoolefine and by recycling to the alkylation reactor, since the content of paraffin components in the product flow is quite low. However, this conclusion does not apply to the conventional ways of skeletal isomerization of olefins, since the concentration of olefins in raffinata stream from the reactor allocation of olefins (selective reactor) is too low. More high-boiling alkylated products can easily dialkylamines obtaining olefins and aromatic compounds. Unreacted alkylates can be allocated in the traditional way, such as simple distillation, and recycled, and aromatic compounds are separated from C4or C5hydrocarbon standard distillation or distillation light ends, and recycle to the alkylation reactor.When tert-alkylbenzoates, olefinic products are essentially pure isobutene, as shown in Table 4. However, when dealkylation was carried out at a higher temperature, tert-olefinic products have been more and more diluted other olefin isomers.This invention can also be used to improve the octane number of FCC gasoline and naphtha-gasoline subjected easy reformer, in one stage. Instead of holding separate stages alkylation and dealkylation alkylation, dealkylation and isomerization of olefins can be carried out simultaneously in the column, catalytic distillation, in which you downloaded an acid catalyst. WITH4-C8olefins in gasoline can be effectively converted into a mixture of olefin isomers. Petrol raw material is fed into the middle section of the column catalytic distillation. The exact position of the point of entry of raw materials on the column may change due to changes in the composition of gasoline to achieve the greatest improvement RON. Top zipper and CC product from the distillation column connected to receive improved gasoline. 1. Method of isomerization of the carbon skeleton WITH4-C15olefins by reacting, at what s in the alkylation conditions to obtain the alkylated aromatic product, dealkylation alkylated aromatic product in the dealkylation conditions to obtain dialkylamino product containing these aromatic compounds and olefins corresponding to the olefins in the alkylation and having a second skeletal distribution, different from the first skeletal distribution.2. The method according to p. 1, where the specified olefin is at least one4-C8olefin.3. The method according to p. 1 where4olefin.4. The method according to p. 1 where5olefin.5. The method according to p. 1, in which the specified alkylation is carried out in conditions providing 10-100% conversion present olefin.6. The method according to p. 5, which specified the alkylation is carried out in conditions providing 30-100% conversion present olefin.7. The method according to p. 1, in which the specified alkylation is carried out in the presence of an acid catalyst.8. The method according to p. 7, where the specified acid catalyst includes a molecular sieve.9. The method according to p. 7, where the specified acid catalyst includes zeolite.10. The method according to p. 1, in which the specified dealkylase is talization includes molecular sieve.12. The method according to p. 10, where the specified acid catalyst includes zeolite.13. The method according to p. 1, in which the specified alkylation is carried out in the presence of an acid catalyst and a specified dealkylation is carried out in the presence of an acid catalyst.14. The way the carbon skeleton isomerization of linear olefins from C4-C8olefins, comprising: (a) the supply of organic aromatic compounds and C4-C15the olefin in the alkylation zone containing an acid catalyst, for maintaining in said reaction zone, the mole ratio of the organic aromatic compound: olefin in the range of from 2 to 100:1 in the conditions for the catalytic alkylation of the interaction part of the organic aromatic compound and the specified olefin with the formation of the alkylation product containing alkilirovanie organic aromatic compound, unreacted organic aromatic compound and unreacted olefin; (b) the Department alkylated organic aromatic compounds from other components of the alkylation product; (C) the filing of specified alkylated organic aromatic compounds in the area dianoga alkylated organic aromatic compounds with formation of the product dealkylation, containing organic aromatic compound, olefin and alkilirovanie organic aromatic compound.15. The method according to p. 14, where the specified zone includes alkylation reactor distillation column type containing acidic catalytic distillation structure in a fixed layer in the distillation reaction zone, where both: (i) specified organic aromatic compound and the olefin catalytically interact with the formation of the specified product alkylation and (ii) the specified alkylation product is subjected to fractional distillation to separate its components and the specified alkilirovanie organic aromatic compound is removed from the specified reactor distillation column type.16. The method according to p. 14, where the specified zone dealkylation includes the reactor distillation column type containing acidic catalytic distillation structure in a fixed layer in the distillation reaction zone, where both: (i) the specified alkilirovanie organic aromatic compound catalytically dissociates with obtaining the specified product dealkylation and (ii) the specified olefin is separated from the product dealkylase is on alkylation includes the reactor distillation column type, containing acidic catalytic distillation structure in a fixed layer in the distillation reaction zone, where both: (i) specified organic aromatic compound and the olefin catalytically interact with the formation of the specified product alkylation; (ii) the specified alkylation product is subjected to fractional distillation to separate its components, specified alkilirovanie organic aromatic compound is removed from the specified reactor distillation column type and the specified area dealkylation includes the reactor distillation column type containing acidic catalytic distillation structure in a fixed layer in the distillation reaction zone, where both: (i) specified alkilirovanie organic aromatic compound catalytically dissociates with obtaining the specified product dealkylation and (ii) the specified olefin is separated from the product dealkylation and removed from the specified reactor distillation column type.18. The method according to p. 14, where the specified reaction zone includes alkylation reactor flow type fixed bed.19. The method according to p. 14, where the specified reaction zone DEA is th reaction zone includes alkylation reactor flow type fixed bed, and the said reaction zone dealkylation includes a straight-flow type reactor with a fixed bed.21. The method according to p. 15, where the specified reaction zone dealkylation includes a straight-flow type reactor with a fixed bed.22. The method according to p. 16 where the specified reaction zone includes alkylation reactor flow type fixed bed.23. The method according to p. 14, where the specified dealkylation is carried out in the conditions for the selective dealkylation of branched olefins.24. The method according to p. 23, where these branched olefins are separated from the specified product dealkylation.25. The method according to p. 14, where the specified olefin in the specified dealkylation product contains a mixture of branched olefins and linear olefins.26. The method according to p. 25, where this mixture of branched olefins and linear olefins are separated from the specified product dealkylation.27. The method according to p. 26, where said mixture of branched olefins and linear olefins in contact with1-C8alcohol in the presence of an acid catalyst under conditions of esterification for selective engagement portion of the branched olefins.28. The method according to p. 27, the manual on p. 27, where specified olefin contains5olefin and branched olefins contain isoamylene.30. The method according to p. 14, where the aforementioned organic aromatic compound contains hydrocarbons.31. The method according to p. 14, where the aforementioned organic aromatic compound contains benzene.32. The method according to p. 14, where the aforementioned organic aromatic compound contains toluene.33. The method according to p. 14, where the aforementioned organic aromatic compound contains xylene.
FIELD: petroleum chemistry, organic chemistry, chemical technology.
SUBSTANCE: method involves carrying out the interaction condensed and polynuclear aromatic hydrocarbons, in particular, naphthalene and biphenyl with polyalkylaromatic hydrocarbons, in particular, with diisopropyl benzene under transalkylation conditions with aim to prepare dialkylated condensed and polynuclear aromatic hydrocarbons. Transalkylation reaction is carried out in the presence of zeolite catalysts comprising 12-membered oxygen rings with diameter of zeolite channels from 5.6 to 7.7 . Invention provides the development of new method for preparing dialkylated polycyclic hydrocarbons.
EFFECT: improved preparing method.
10 cl, 2 tbl, 31 ex