RU2177930C1 - Alkene oligomers production process - Google Patents

Abstract

FIELD: petrochemical processes. SUBSTANCE: C3- and/or C4- and/or C5-alkenes are subjected to chemical conversion in presence of acidic ion-exchange catalysts and inert and/or low-reactive hydrocarbons and/or polar substances followed by distillation of at least unreacted hydrocarbons. Oligomerization conditions are controlled to maintain in reaction products leaving reaction zone no more than 15% and preferably no more than 3% oligomers with number of carbon atoms exceeding predetermined number. After distilling away at least major part of unreacted hydrocarbons, residue is separated by rectification into stream including dimmers and/or oligomers with lower number of carbon atoms and bottom product containing basically oligomers with specified number of carbon atoms. EFFECT: facilitated process control. 15 cl, 4 dwg, 9 ex

Description

 The invention relates to the field of production of oligomers for organic syntheses, in particular for the production of alkyl phenolic additives, plasticizers, non-ionic detergents and oil additives.

The known method [US patent 2870217 from 01.20.59] converting propene to dimers and oligomers by contacting it at a temperature of from 400 ^o to 600 ^o F (from 204 ^o to 316 ^o C) in the presence of dilute aqueous solutions of mineral acids, for example sulfuric, hydrochloric phosphoric. The disadvantage of this method is the high corrosiveness of the working environment and the formation of a large number of by-products of oxygen-containing products.

The known method [US patent 4334118 from 08.06.82] oligomerization of alkenes, including propene in propane-propene mixtures, by contacting with a solid acid catalyst containing phosphoric acid on a support (silica gel) in the gas phase at a temperature of 160-235 ^o C. Oligomerization is recommended in the presence of polar agents - alcohol (s) and water. The disadvantage of this method is the high temperature in the reaction zone and the need for high energy and investment.

The known method [US patent 4571439 from 12/18/86] oligomerization of alkenes, in particular propene, in a mixed C ₃ -C ₄ stream at a temperature of 80-130 ^o In the presence of an acidic ion-exchange resin and methanol. When using this method, however, C ₆ -C ₈ alkenes, which are products of dimerization and codimerization of propene and butenes, predominate in the reaction product. In this case, oligomers are formed in smaller quantities and methods for the targeted production of oligomers with a given number of carbon atoms are not indicated.

Known and closest to our proposed invention method [Patent RU 2137808, 09/20/99, Bull. 26] the preparation of dimerization and oligomerization products or mixtures containing at least dimers and / or trimers of non-tertiary C ₃ -C ₆ alkenes, according to which the conversion of non-tertiary C ₃ -C ₆ alkenes is carried out in the presence of an acidic ionic catalyst at elevated temperature. As a variant of the process of chemical conversion in the reaction (s) zone (s) is carried out in the presence of polar agents, for example alcohols. It is possible (as can be seen from the examples) the chemical conversion is carried out in the presence of inert or low-reactive hydrocarbons, for example alkanes.

 The specified method is intended to produce high-octane gasoline mixtures and leads to mixtures of dimers and oligomers having different numbers of carbon atoms. Patent RU 2137808 does not contain methods for the targeted production of oligomers with a given number of carbon atoms, which are necessary for chemical syntheses.

We propose a method for producing oligomers with a given number (s) of carbon atoms by chemical conversion of C ₃ and / or C ₄ and / or C ₅ alkenes in the presence of acidic ion-exchange catalysts and inert and / or low-reactive hydrocarbons and / or polar substances with subsequent distillation of at least unreacted hydrocarbons, characterized in that the conditions of oligomerization are controlled in such a way that among the reaction products withdrawn from the oligomerization zone (s) contains no more than 15%, preferably not more than 3%, oligomers with the number of carbon carbon atoms exceeding the specified one, after distillation of at least most of the unreacted hydrocarbons, the residue is separated by distillation and the stream, including dimers and / or oligomers with a smaller number of carbon atoms, is distilled off, and the bottoms product containing predominantly oligomers with a given number of carbon atoms is removed. Alternatively, a method is proposed, which consists in the fact that at least part of the distilled stream of unreacted hydrocarbons is recycled to the oligomerization zone (s).

Alternatively, a method is proposed, which consists in the fact that the distillation of unreacted hydrocarbons is carried out in a vertical mass transfer apparatus, in the upper part of which hydrocarbon (s) with a boiling point (s) of at least 20 ^° C exceeding (their) boiling point are most volatile from the resulting dimers and / or oligomers.

 Alternatively, a method is proposed in which the distillate and / or side stream from the strengthening part of the distillation zone in which dimers and / or oligomers are distilled from a product with a given number of carbon atoms is at least partially recycled to the oligomerization zone (s).

 Alternatively, a method is proposed, which consists in the fact that oligomers with a given number of carbon atoms are distilled from higher boiling products.

 Alternatively, a method is proposed that consists of two oligomeric products with predetermined numbers of carbon atoms "m" and "n", where n> m, oligomers with the number of carbon atoms "n" are removed from the bottom of the specified distillation zone, and oligomers with the number carbon atoms "m" are removed from above and / or side of said distillation zone, and preferably then hydrocarbons with a carbon number less than "m" are distilled off and returned to the oligomerization zone (s), and possibly polar substance (s) and / or and an inert solvent.

 Alternatively, a method is proposed that consists in the use of non-tertiary alkenes with the same number of carbon atoms or mixtures thereof with alkanes, or tertiary alkenes with the same number of carbon atoms or mixtures thereof with alkanes and possibly non-tretic alkenes.

As an option, a method is proposed, namely, in the oligomerization zone (s), alkanes or alkane mixtures with a boiling point (s) of at least 20 ^° C lower than the obtained oligomers with a given number of carbon atoms are used as an inert solvent , and preferably not less than 20 ^{° C.} higher than the starting alkenes subjected to oligomerization.

 Alternatively, a method is proposed that oligomerization is carried out in two or more consecutive reaction zones with a catalyst, between which the stream is cooled or the unreacted hydrocarbons are distilled off from at least oligomers with a given number of carbon atoms and the distillate is fed to the next reaction zone.

 Alternatively, a method is proposed that when processing mixtures comprising tertiary and non-tertiary alkenes, for example isobutene and n-butenes, tertiary alkenes are initially converted to dimers and / or oligomers and / or tertiary alcohols and / or alkyl tert-alkyl ethers and / or dioxanes, after which a stream of unreacted hydrocarbons, including non-tertiary alkenes, is distilled off and oligomerized.

 Alternatively, a method is proposed, which consists in the fact that the concentration of water and / or alcohol (s) formed by the interaction of water with the starting alkene (s) and / or lower (s) is maintained in the catalyst and the mixture in contact with it alcohol (s) in an amount that suppresses the formation of oligomers with the number of carbon atoms in excess of a given. Alternatively, a method is proposed, which consists in using a propene or propane-propene mixture as a raw material, and propene trimers and / or tetramers as a target product.

 Alternatively, a method is proposed that consists in rectifying a mixture containing predominantly propane and propene from the reaction mass and introducing a stream containing mainly propane from below and a mixture containing from 30 to 70% propene which is recycled to the zone above. (s) contacting with an ion exchange catalyst.

Alternatively, a method is proposed that consists in the fact that the oligomerization of tertiary alkenes is carried out at a temperature of from 50 to 100 ^{o C.} and the oligomerization of non-tertiary alkenes is carried out at a temperature of from 90 to 140 ^o C.

 Alternatively, a method is proposed, consisting in the fact that as the catalyst (s) use large-pore sulfocationionites.

 The term "tertiary alkenes" means alkenes having a double bond at a carbon atom bonded to three other carbon atoms. The term "non-tertiary alkenes" means all other alkenes of both normal and branched structure.

 To carry out the catalytic oligomerization of alkenes, various types of reactors can be used using various methods of removing reaction heat: through tubes of shell-and-tube apparatuses, by interzone cooling of flows, by cooling and recycling to the inlet of the reactor (s) part of the reaction mass, by evaporation of part of the reaction mass and etc.

 The application of the invention is illustrated in FIG. 1-4 and examples 1-9.

 These drawings and examples do not exhaust the possible uses of the invention and other technical solutions are possible, subject to the essence set forth in the claims.

 According to FIG. 1, a feed hydrocarbon stream F, (line 1) and optionally an inert solvent S (line 2) are fed into the process. Line 2 may (may) also serve (s) the polar substance (s).

 Specified (e) stream (s), possibly after connecting recycle stream 8 and / or recycle stream 11, is sent to line P through line 3 (in the drawing it is shown in the shell-and-tube version with the supply of refrigerant XA into the annulus, although other types are acceptable reactors).

 The reaction mixture 4 is removed from the reactor R, which is sent to the apparatus for distillation of unreacted hydrocarbons K-1, which can be a simple distillation apparatus, or a distillation column, or an absorption apparatus. In the latter case, a sufficiently high-boiling absorbent A stream is supplied to the top of K-1 through line 4a, which part of stream 9 can preferably be directed (stream 13a). Bottom of apparatus K-1, stream 5 is output including oligomers and possibly dimers, an inert solvent, and polar substance (s). From above K-1, a stream 6 is selected containing unreacted hydrocarbons, at least part of which (possibly after condensation) is removed from the system (line 7) and / or recycled to reactor P (line 8).

 Stream 5 is sent to a distillation column K-2. From the K-2 column, a stream 9 is withdrawn from below from below, containing mainly oligomers with a given number of carbon atoms “n”, and from above is a vapor stream which is condensed and at least partially returned to K-2 via line 10a as a reflux. The rest of the condensate may optionally be discharged along line 10. Stream 10 includes dimers and / or oligomers with a smaller (than "n") number of carbon atoms, as well as an inert diluent and / or polar substance (s). Stream 10 is fully or partially recycled to the inlet of reactor P (line 11) and / or output via line 12.

 It is possible that a side stream 11a is withdrawn from the reinforcing part of the K-2 column, which is recycled to the inlet of the reactor R. Moreover, the stream 10 may not be output.

 Stream 12 can be rectified in an additional distillation column, where lighter components are distilled off and preferably recycled to the oligomerization zone (s), and a product with a given number of carbon atoms “m” is obtained in the residue.

 Stream 9 is withdrawn from K-2 via line 13. In the case of an increased content of high boiling substances (above the boiling point of the target product) of substances, in particular oligomers with the number of carbon atoms above a predetermined number "n", can be fed into the apparatus (column) K -3 (line 14), where the target product (stream 15) is distilled from high-boiling impurities discharged from below (stream 16).

 The circuit of FIG. 2 differs from FIG. 1 in that three successive reactors R-1, P-2 and P-3 are used with intermediate cooling of streams 3a and 3b, as well as the possible presence (when using the initial propane-propene mixture) of separation (rectification) of the unconverted propane-propene mixture ( stream 6), which is sent for this along line 7 to the K-3 column.

 Columns K-1 and K-2 perform functions similar to those of columns K-1 and K-2 in FIG. 1.

 From the K-3 column from above (stream 15a), a propane-propene mixture with an increased concentration of propene is withdrawn, which is recycled to the oligomerization reactor (s).

 A stream 15b containing propane is discharged from below.

 The circuit of FIG. 3 differs from the diagrams in FIG. 1 and 2 in that it provides the possibility of withdrawing the side stream 11 from the K-2 distillation column, as well as the possibility of producing two oligomeric products with predetermined numbers of carbon atoms "m" and "n" (where n> m).

 The purpose and numbering of the streams preceding K-2 are similar to those indicated in FIG. 1 and FIG. 2.

 The bottom stream K-2, stream 9, contains mainly oligomers with the number of carbon atoms "n".

 Side stream 11 from K-2 contains mainly oligomers with the number of carbon atoms "m". The specified stream can be withdrawn as a second product along line 14 and / or sent to column 3. Alternatively, a stream 10, outputted from above K-2, can be directed to line K-3 in full or in part on line 12.

 In column K-3, a stream containing predominantly oligomers with the number of carbon atoms "m" is withdrawn from below along line 15. On top of K-3, a stream of lighter boiling components is discharged via line 16, which is preferably recycled to the oligomerization unit and / or removed from the system via line 17.

 In FIG. 4 shows a process for processing a mixture including tertiary and non-tertiary alkenes.

 The hydrocarbon feed stream F is fed through line 1 to the tertiary alkenes conversion zone. An inert solvent S and a polar substance can also be added to it, increasing the selectivity of oligomerization (stream 2) and reagent (s) R, chemically reacting (e) with tertiary (s) alkene (s) (line 3). The reaction mixture from the specified zone through line 4 is sent to a distillation column K-1.

 Bottom of the K-1 column, through line 5, the conversion product (s) of the tertiary alkene (s) are withdrawn. A mixture of unreacted hydrocarbons, not containing a significant amount of tertiary alkenes (stream 6), which is sent to the zone of conversion of non-tertiary alkenes, is withdrawn from the top of line 6.

 Stream 5 may be subjected to additional rectification (not shown).

 An inert solvent S and polar substances that increase the oligomerization selectivity (stream 8) can also be fed into the conversion zone of non-tertiary alkenes.

 The reaction mixture from the specified zone through line 9 is fed to a distillation column K-2. Bottom of column K-2, a stream 10 is withdrawn, including mixtures of oligomers and possibly non-tertiary alkenes dimers. A stream of unreacted hydrocarbons is withdrawn from above (stream 11), which can be removed from the system via line 12 and / or recycled to the non-tertiary alkenes transformation zone along lines 13, 14 and 7.

 Stream 10 is fed to a distillation column K-3. From the bottom of the K-3 column, line 15 displays a stream including oligomers of non-tertiary alkenes with a given number of carbon atoms (which can be further distilled from higher boiling components). At the top of the K-3 column, a stream is output via line 16, including oligomers with fewer carbon atoms (possibly dimers), as well as an inert solvent and polar substance (s). It is recycled to the non-tertiary alkenes transformation zone.

Examples
In the examples, coarse-grained fine-grained sulfoionite catalysts having a particle size of 0.3-1.3 mm and a static exchange capacity of SOE (mg equivalent H ⁺ per 1 g of dry catalyst) were used: Amberlist-15 - SOE = 4.7, Amberlist-38 - SOE = 5.3, KU-23 - SOE = 4.1, Bayer K-2611 - SOE = 4.8, and also a molded KIF catalyst obtained by sulfonation of a mixture of styrene-divinylbenzene copolymer and polyethylene (cylinders with a diameter of 5 mm and a length 6 mm, SOE = 3.6).

Example 1
Processing is carried out according to FIG. 1.

 As raw material F, a pronan-propene mixture containing 70% propene is used. As an inert diluent, n-pentane is used.

 The target product is propene trimers containing 9 carbon atoms.

 The reactor K is loaded with a KU-23 catalyst.

 Stream 3 contains 24.9% propene, 10.1% propane, 55.4% n-pentane, 7.1% propene dimers, and 1.2% isopropanol.

The reactor is maintained at a temperature of 100 ^{° C.} and a load of 0.5 l / l cat. hour.

 The conversion of propene is 87%.

 Reaction stream 4 contains 3.2% propene, 10.1% propane, 55.4% n-pentane, 7.2% propene dimers, 21.6% propene trimers, 0.5% components with more than 9 carbon atoms and 0.3% isopropanol.

 A propane-propene mixture (stream 6) containing 23.2% propene and 72.3% propane, which is withdrawn from the system, is distilled off from above K-1 column in an amount of 0.38 kg / kg F.

 1.78 kg / kg are withdrawn from the top of the K-2 column after condensation of the effluent vapor stream. F, stream 10 containing 11.2% of dimers of propene, 87.2% of n-pentane and 0.5% of isopropanol is recycled to the reactor. P. The rest of the condensate is returned to the column through line 10a.

 Bottom of the K-2 column (stream 9), a mixture containing 1.2% propene dimers, 96.0% propene trimers and 2.2% compounds with more than 9 carbon atoms is removed as the target product.

 Alternatively, from the reinforcing part of the column (its upper part), lateral extraction 11a is removed in the amount of 1.78 kg / kg F, which is close to the composition of stream 10 indicated above (10.9% propene dimers, 0.3% propene trimers, 87.3 % n-pentane and 0.5% isopropanol), which are recycled to the inlet of the reactor R. At the same time, stream 10 is not output.

Example 2
Processing is carried out according to FIG. 2.

 As raw material F, a propane-propene mixture containing 70% propene is used. A mixture of hexanes is used as an inert diluent.

 The target product is propene trimers containing 9 carbon atoms.

 The KIF catalyst is loaded into the R-1 reactor.

 Part of the reaction mass leaving the reactor R-1, after cooling, is recycled to the inlet of P-1 (not shown).

 The Bayer K-2611 catalyst is loaded into the R-2 and R-3 reactors.

The reactors maintain temperatures and loads: in R-1 - 90 ^o C and 1.0 l / l cat. hour, in R-2 - 110 ^o C and 1.5 l / l cat. hour, in R-3 - 100 ^o C and 1.5 l / l cat. hour.

 Stream 3 fed to P-1 contains 17.7% propene, 7.3% propane, 5.9% propene dimers, 67.6% hexanes, and 0.8% isopropanol.

 The propene conversion in the reactor system is 85%.

 The reaction mixture (stream 4) contains 2.7% propene, 7.3% propane, 67.6% hexanes, 6.0% propene dimers, 14.9% propene trimers, 0.4% propene tetramers and 0.3% isopropanol.

 The propane-propene mixture (stream 6) is distilled off from above K-1 column in an amount of 0.47 kg / kg F, which is then sent to K-3 column along line 7.

 Upon distillation of the bottom residue from the K-1 column in the K-2 column from the bottom in an amount of 0.72 kg / kg F, a product containing 95.6% propene trimers is withdrawn.

 On top of the K-2 column in the amount of 3.43 kg / kg F, a stream 10 containing 8.1% propene dimers, 91.0% inert diluent (hexanes) and 0.4% isopropanol is recovered, which is recycled to the inlet of P- 1.

 In the K-3 column, from the bottom, in an amount of 0.30 kg / kg F, a stream containing 95% propane is discharged.

 On top of K-3 in an amount of 0.17 kg / kg F, a propane-propene mixture containing 70% propene is removed, which is recycled to the inlet of the P-1 reactor.

Example 3
Processing is carried out according to FIG. 3.

 As raw material F, a propane-propene mixture containing 70% propene is used. The introduction of an inert diluent is not performed.

 Two products are obtained as the target ones - the first contains propene tetramers (12 carbon atoms), the second contains propene trimers (9 carbon atoms).

 The oligomerization unit is similar to FIG. 1.

 Amberlist-38 catalyst is loaded into the reactor.

 Stream 3 contains 39.0% propene, 15.7% propane, 24.0% propene dimers, and 20.1% propene trimers.

The reactor is maintained at a temperature of 130 ^{° C.} and a load of 1.0 l / l cat. hour.

 The propene conversion is 93%.

 The reaction mixture (stream 4) contains 2.7% propene, 15.7% propane, 24.1% propene dimers, 40.2% propene trimers and 16.1% propene tetramers.

 A propane-propene mixture (stream 6) containing 14.0% propene and 80.4% propane, which is removed from the system, is distilled off from above K-1 columns in an amount of 0.35 kg / kg F.

A mixture (stream 10) containing 0.1% C ₃ hydrocarbons, 37.5% propene dimers and 62.2% propene trimers is discharged from the top of the K-2 column in an amount of 1.15 kg / kg F. The specified mixture is divided into two streams, one of which in the amount of 0.575 kg / kg F through line 13 is recycled to the reactor, and the remaining amount via line 12 is sent to the distillation column K-3.

 Bottom of the K-2 column in the amount of 0.29 kg / kg F the product is withdrawn (stream 9) containing 99.0% of propene tetramers and 1.0% of propene trimers.

 On top of the K-3 column in an amount of 0.22 kg / kg F, stream 16 containing 99.2% of propene dimers is withdrawn, which is recycled to the reactor inlet.

 From the bottom of the K-3 column in the amount of 0.36 kg / kg F the product is withdrawn (stream 15) containing 99.3% of propene trimers and 0.5% of propene dimers.

Example 4
The processing of the propane-propene mixture is carried out according to the scheme, which is a combination of FIG. 2 and FIG. 3, namely the circuit of FIG. 3 is supplemented by a distillation column for separating the propane-propene mixture (shown in Fig. 2), taken from the top of the K-1 column. The numbering of columns in the example corresponds to FIG. 3.

 The starting propane-propene mixture contains 68% propene, 27% propane and 5% isobutane.

Isobutane is used as an inert diluent (normal boiling point is -11.7 ^° C).

 Two products are obtained as the target — the first contains propene trimers (9 carbon atoms), the second contains propene dimers (6 carbon atoms).

 Amberlist-15 catalyst is loaded into the R-1 and R-2 reactors.

 After cooling, part of the reaction mass exiting the R-1 reactor is recycled to the inlet of R-1 (not shown in the figure).

 Amberlist-38 catalyst is loaded into the R-3 reactor.

The reactors support temperatures and loads: in R-1 - 100 ^o C and 1.0 l / l cat. hour, in R-2 - 120 ^o C and 1.5 l / l cat. hour, in R-3 - 140 ^o С and 2.0 l / l cat. hour.

 Stream 3 fed to P-1 contains 31.4% propene, 18.7% propane, 42.1% isobutane, 5.5% propene dimers, 1.1% propene trimers, and 1.0% isopropanol.

 The propene conversion in the reactor system is 95%.

 The reaction mixture (stream 4) contains 1.9% propene, 18.7% propane, 42.1% isobutane, 7.2% propene dimers, 28.6% propene trimers, 1.0% propene tetramers and 0.25% isopropanol.

 A propane-propene mixture (stream 6) containing 9.1% propene was distilled off from above K-1 column in an amount of 0.39 kg / kg F. The specified mixture is then sent to a distillation column (K-3 in Fig. 2), on top of which a propane-propene mixture containing 30% propene is taken, and propane is taken from the bottom.

 Upon rectification of the bottom residue from the K-1 column in the K-2 column from the bottom in an amount of 0.56 kg / kg F, a product containing 96.2% propene trimers is withdrawn (stream 9).

 On top of the K-2 column in an amount of 0.75 kg / kg F, a stream 10 containing 98.3% isobutane is withdrawn, which is recycled to line P-1 through line 13.

 As a lateral screening in an amount of 0.19 kg / kg F, a stream 11 containing 30% isobutane, 68.3% propene dimers and 1.0% propene trimers, which is sent to a K-3 distillation column, is removed from K-2.

 In the K-3 column, from the bottom, in an amount of 0.13 kg / kg F, a product containing 97.4% of propene dimers is withdrawn (stream 15).

 On top of K-3 in an amount of 0.06 kg / kg F, a mixture containing 99.0% of isobutane (stream 16) is removed, which is removed from the system.

Example 5
Processing is carried out according to FIG. 1.

 As raw material F, concentrated tertiary amylenes (98%) are used.

 The target product is trimers of tert-amylene containing 15 carbon atoms.

 Amberlist-38 catalyst is loaded into reactor P.

 Stream 3 contains 38.4% of isoamylenes, 60.2% of tert-amylene dimers, and 0.5% tert-amyl alcohol.

The reactor is maintained at a temperature of 120 ^{° C.} and a load of 0.7 l / l cat. hour.

 The conversion of tert-amylene is 95%.

 Reaction stream 4 contains 1.7% tert-amylene, 87.6% tert-amylene dimers, 11.0% tert-amylene trimers, 0.2% tert-amylene tetramers and 0.2% isopropanol.

On top of the K-1 column in an amount of 0.05 kg / kg F, a mixture (stream 6) containing 76.5% tert-amylene and 20.0% C ₄ hydrocarbons is withdrawn from the system.

 On top of the K-2 column in an amount of 2.26 kg / kg F output stream 10 containing 98.5% of tert-amylene dimers. It is divided into two streams, one of which in the amount of 1.58 kg / kg F through line 11 is recycled to the reactor, and the rest through line 12 is removed from the system.

 Bottom of the K-2 column (stream 9) in an amount of 0.28 kg / kg F, the desired product is withdrawn containing 97.3% of tert-amylene trimers and 2.0% of tert-amylene tetramers.

Example 6
Processing is carried out according to FIG. 4.

As raw material F, a C ₄ fraction of gasoline pyrolysis hydrocarbons containing 45% isobutene, 40% n-butenes, 15% isobutane and n-butane is used.

In the tertiary alkenes conversion unit, isobutene is oligomerized. Isobutene oligomerization is carried out at a temperature of 70-90 ^o C in two successive adiabatic reactors with intermediate cooling, filled with Amberlist-15 catalyst.

In the conversion unit, the total feed volumetric feed rate of 0.5-0.6 h ^{-1 is} maintained, while the conversion of n-butenes is 14%, of isobutene - 92%.

 Tert-butanol is also fed to the reactor assembly in an amount of 0.03 kg / kg F.

The stream withdrawn from the conversion unit containing 0.5% tert-butanol, 3.5% isobutene, 33% n-butenes, 41.8% C ₈ alkenes and 3.8% C ₁₂ alkenes is sent to a K-1 distillation column.

 On top of the K-1 column in an amount of 0.55 kg / kg F mixture (stream 6) containing 6.6% isobutene, 63% n-butenes, 28.5% isobutane and n-butane, as well as 1.0% t -butanol, which is sent to the site of conversion of non-tertiary alkenes.

Bottom of the K-1 column (stream 5), an oligomeric product containing 91% C ₈ alkenes and 9% C ₁₂ alkenes is withdrawn in an amount of 0.47 kg / kg F.

In the site of conversion of non-tertiary alkenes, n-butenes are oligomerized at a temperature of 110-130 ^{° C.} in two successive adiabatic reactors with intermediate cooling, filled with Amberlist-35 catalyst.

 0.68 kg / kg F is also fed to the non-tertiary alkenes conversion unit. The F stream is selected as the top product of the K-3 column.

The conversion site supports the total feed volumetric feed rate of 0.4-0.5 h ^-1 , while the conversion of n-butenes is 84%, isobutene - 99%.

 The reaction mixture from the conversion unit (stream 9) containing 4.1% n-butenes, 13.5% isobutane and n-butane, 54% butene dimers, 24.4% butene trimers and 4.0% butene tetramers is sent to distillation column K-2.

From the top of the K-2 column, 0.20 kg / kg F stream C ₄ hydrocarbons (stream 12) containing 23.5% n-butenes, 76% isobutane, which is removed from the system, are taken.

 The bottoms product of the K-2 column is sent to a distillation column K-3.

0.68 kg / kg F stream (stream 16) containing 7.4% C ₄ hydrocarbons, 90% butene dimers and 2.5% butene trimers, which is recycled to the non-tertiary alkenes conversion unit, is taken at the top of K-3 column.

 Below the K-3 column (stream 15), 0.33 kg / kg F of the target product is withdrawn in the amount of 1% butene dimers, 85% butene trimers and 14% butene tetramers.

Example 7
Processing is carried out according to FIG. 4.

As raw material F, a C ₄ hydrocarbon fraction similar to Example 6 is used.

In the tertiary alkenes conversion unit, isobutene is reacted with ethanol to obtain ethyl tert-butyl ether (ETBE). The interaction is carried out at a temperature of 50-70 ^o C in two successive reactors filled with Amberlist-15 catalyst.

In the conversion unit, the total feed volumetric feed rate of 0.3-0.4 h ^{-1 is} maintained, while the conversion of isobutene is 90%.

 Ethanol is also fed to the conversion unit in an amount of 0.4 kg / kg F.

 The stream withdrawn from the conversion unit, containing 3.2% isobutene, 28.2% n-butenes, 52.75 ETBE, 4.8% ethanol, is sent to a K-1 distillation column.

 On top of the K-1 column in an amount of 0.6 kg / kg F mixture (stream 6) containing 7.5% isobutene, 66% n-butenes, 25.7% isobutane and n-butane, as well as 1.0% ethanol , which is sent to the site of conversion of non-tertiary alkenes.

 Bottom of the K-1 column (stream 5), an oligomeric product containing 91.5% ETBE and 8.3% ethanol is withdrawn in an amount of 0.8 kg / kg F.

In the site of conversion of non-tertiary alkenes, oligomerization of n-butenes is carried out at a temperature of 115-130 ^o C in two successive adiabatic reactors with intermediate cooling, filled with Amberlist-35 catalyst.

 The non-tertiary alkenes conversion unit is also supplied in an amount of 1.07 kg / kg F stream selected as the top product of the K-3 column, in an amount of 0.23 kg / kg F stream 13 selected as the top product of the K-2 column and in an amount of 0.01 kg / kg F sec-butanol.

In the conversion unit, the total feed volumetric feed rate of 0.4-0.5 h ^{-1 is} maintained, while the conversion of n-butenes is 80%, of isobutene - 97%.

 The reaction mixture from the conversion unit (stream 9) containing 24.5% n-butenes, 13.9% isobutane and n-butane, 45.2% butene dimers, 15.8% butene trimers and 0.5% butene tetramers, sent to a distillation column K-2.

0.47 kg / kg F hydrocarbon stream C ₄ (stream 11) containing 0.5% isobutene, 33.7% n-butenes, 65.5% isobutane, half of which is removed from the system (stream 12), and the remainder is recycled to the non-tertiary alkenes conversion unit (stream 13).

 The bottoms product of the K-2 column is sent to a distillation column K-3.

On top of the K-3 column, 1.07 kg / kg F stream 16, containing 6.5% C ₄ hydrocarbons, 92% butene dimers and 1.5% butene trimers, which is recycled to the non-tertiary alkenes conversion unit, is taken.

 From the bottom of the K-3 column (stream 15), 0.36 kg / kg F of the target product is withdrawn containing 1% butene dimers, 96.5% butene trimers and 2.5% butene tetramers.

Example 8
Processing is carried out according to FIG. 1.

As raw material F, a mixture of C ₄ -C ₅ hydrocarbons containing 40% isobutene, 30% C ₄ alkanes, 20% tertiary amylene and 10% C ₅ alkanes is used.

 The target product is isobutene trimers containing 12 carbon atoms.

 The reactor K is loaded with a KU-23 catalyst.

Stream 3 contains 18.7% isobutene, 14.1% C ₄ alkanes, 9.7% tertiary amylene, 5.2% C ₅ alkanes, 31.7% C ₈ olefins, 15.4% C ₉ , 4 olefins, 4% olefins C ₁₀ , 0.7% tert-butyl alcohol and 0.2% tert-amyl alcohol.

The reactor is maintained at a temperature of 80 ^{° C.} and a load of 0.7 l / l cat. hour.

 The conversion of isobutene is 97%, tert-amylene - 70%.

Reaction stream 4 contains 0.6% isobutene, 14.1% C ₄ alkanes, 2.9% Tertiary amylene, 5.2% C ₅ alkanes, 31.7% C ₈ olefins, 15.4% C ₉ , 4 olefins 5% olefins C ₁₀ , 13.5% olefins C ₁₂ , 6.7% olefins C ₁₃ , 4.2% olefins C ₁₄ , 0.9% olefins C _{15 and higher} , 0.2% tert-butyl alcohol and 0.05% tert-amyl alcohol.

A mixture (stream 6) containing 2.5% isobutene, 63.1% C ₄ alkanes, 11.7% tertiary amylene, 20.9% C ₅ alkanes is discharged from the top of K-1 column in an amount of 0.48 kg / kg F and 0.9% tert-butyl alcohol, which is removed from the system.

On top of the K-2 column in an amount of 1.11 kg / kg F, a stream 10 containing 1.5% C ₅ hydrocarbons, 60.5% C ₈ olefins, 29.4% C9 olefins, 8.4% C ₁₀ olefins, is withdrawn 0.1% C ₁₂ olefins and 0.1% tert-amyl alcohol, which are recycled via line 11 to the reactor.

From the bottom of the K-2 column (stream 9) in an amount of 0.54 kg / kg, a mixture containing 0.5% olefins C ₁₀ , 53.0% olefins C ₁₂ , 26.3% olefins C ₁₃ , 16.7% olefins is withdrawn C ₁₄ , 3.5% of olefins C _{15 and above} , which is sent to a distillation column K-3.

From the bottom of the K-3 column in the amount of 0.25 kg / kg, stream 16 is selected containing 1.0% C ₁₂ olefins, 55.4% C ₁₃ olefins, 35.9% C ₁₄ olefins, 7.7% C ₁₅ olefins _{and above} which is logged out.

The target product (stream 15) containing 0.9% C ₁₀ olefins, 98.1% C ₁₂ olefins and 1.0% C ₃₁ olefins is withdrawn from the top of the K-3 column in an amount of 0.29 kg / kg F.

Example 9
Processing is carried out according to FIG. 1.

 As raw material F, a propane-propene mixture containing 76% propene is used. The introduction of an inert diluent is not performed.

 Amberlist-38 catalyst is loaded into the reactor.

 An additional 0.21 kg / kg F recycle stream taken from the top of the K-2 column is also additionally fed to the reactor.

In the reactor maintain a temperature of 120-130 ^o With a load of 1.0 l / l cat. hour.

 The propene conversion is 93%.

 The stream withdrawn from the P-1 reactor, containing 19.7% propane, 4.3% propene, 17.2% propene dimers, 53.0% propene trimers and 5.7% propene tetramers, is sent to the absorption phase in the gas phase column K-1.

 An absorbent (stream 4a) containing 1% propene dimers, 90% propene trimers and 9.0% propene tetramers is fed to the top of K-1 column in an amount of 1.21 kg / kg F. As the absorbent, a part of the bottoms product of the K-2 column is used (stream 13a).

 A propane-propene mixture (stream 6) containing 18.0% propene and 82.0% propane, which is withdrawn from the system, is distilled off from above K-1 column in an amount of 0.29 kg / kg F.

 From the bottom of the K-1 column in the amount of 2.13 kg / kg F, a saturated absorbent is removed (stream 5), which is sent to a K-2 distillation column.

At the top of the K-2 column in an amount of 0.22 kg / kg F, a stream 10 is selected containing 2% C ₃ hydrocarbons, 94% propene dimers and 4% propene trimers, which is returned via line 11 to the P-1 reactor for recycling .

 From the bottom of the K-2 column in the amount of 1.91 kg / kg F the product is withdrawn (stream 9) containing 1% propepe dimers, 90% propene trimers and 9% propene tetramers, some of which in the amount of 1.21 kg / kg F are sent to a K-1 column as absorbent (stream 13a), and the rest in the amount of 0.70 kg / kg F is withdrawn as the target product (stream 13).

Claims (15)

1. A method of producing oligomers with a given number (s) of carbon atoms by chemically converting C ₃ and / or C ₄ and / or C ₅ alkenes in the presence of acidic ion-exchange catalysts and inert and / or low reactive hydrocarbons and / or polar substances followed by distillation of at least unreacted hydrocarbons, characterized in that the oligomerization conditions are controlled in such a way that among the reaction products removed from the oligomerization zones (s), no more than 15%, preferably no more than 3%, oligomers with the number of carbon a ohms, exceeding a predetermined, after distilling off at least most of the unreacted hydrocarbon is separated by distillation and the residue distilled stream comprising dimers and / or oligomers with less carbon atoms, and outputting a bottoms product comprising primarily oligomers with a specified number of carbon atoms.  2. The method according to p. 1, characterized in that at least part of the distilled stream of unreacted hydrocarbons is recycled to the oligomerization zone (s). 3. The method according to p. 1, characterized in that the distillation of unreacted hydrocarbons is carried out in a vertical mass transfer apparatus, in the upper part of which hydrocarbon (s) with a boiling point (s) of at least 20 ^o С exceeding (them) are fed as absorbent the boiling point of the most volatile of the resulting dimers and / or oligomers.  4. The method according to p. 1, characterized in that the distillate and / or side stream from the strengthening part of the distillation zone, in which the dimers and / or oligomers are distilled from the product with a given number of carbon atoms, are at least partially recycled to the oligomerization zone (s) .  5. The method according to p. 1, characterized in that the oligomers with a given number of carbon atoms are distilled from higher boiling products.  6. The method according to p. 1, characterized in that two oligomeric products with given numbers of carbon atoms "m" and "n" are obtained, where n> m, oligomers with the number of carbon atoms "n" are removed from the bottom of the specified distillation zone, and oligomers with the number of carbon atoms "m" is removed from above and / or side of the specified distillation zone and preferably then hydrocarbons with the number of carbon atoms less than "m" are distilled off and returned to the oligomerization zone (s), and possibly polar substance (s) and / or inert solution spruce.  7. The method according to p. 1, characterized in that the raw materials use non-tertiary alkenes with the same number of carbon atoms or mixtures thereof with alkanes, or tertiary alkenes with the same number of carbon atoms or mixtures thereof with alkanes and possibly non-tretic alkenes. 8. The method according to p. 1, characterized in that in the oligomerization zone (s), alkanes or alkane mixtures with a boiling point (s) of at least 20 ^° C lower than the obtained oligomers with a given number of carbon are used as an inert solvent atoms, and preferably not less than 20 ^o With higher than that subjected to oligomerization of the original alkenes.  9. The method according to p. 1, characterized in that the oligomerization is carried out in two or more consecutive reaction zones with a catalyst, between which the stream is cooled or distilled unreacted hydrocarbons are distilled from at least oligomers with a given number of carbon atoms and the distillate is fed to the next reaction zone.  10. The method according to p. 1, characterized in that when processing mixtures comprising tertiary and non-tertiary alkenes, for example isobutene and n-butenes, the tertiary alkenes are initially converted into dimers and / or oligomers and / or tertiary alcohols and / or alkyl tertiary alkyl esters and / or dioxanes, after which a stream of unreacted hydrocarbons, including non-tertiary alkenes, is distilled off and oligomerized.  11. The method according to p. 1, characterized in that the concentration of water and / or alcohol (s) formed by the interaction of water with the starting alkene (s) and / or lower (in the catalyst and in contact with it mixture) is maintained s) alcohol (s) in an amount that suppresses the formation of oligomers with the number of carbon atoms in excess of a given.  12. The method according to p. 1, characterized in that the propene or propane-propene mixture is used as raw material and propene trimers and / or tetramers are obtained as the target product.  13. The method according to p. 12, characterized in that the mixture is distilled from the reaction mass, containing mainly propane and propene, is subjected to rectification, and a stream containing mainly propane is withdrawn from below and a mixture containing from 30 to 70% of propene, which recycle to the ionite catalyst contact zone (s). 14. The method according to p. 1, characterized in that the oligomerization of tertiary alkenes is carried out at a temperature of from 50 to 100 ^o C, and the oligomerization of non-tertiary alkenes is carried out at a temperature of from 90 to 140 ^o C.  15. The method according to p. 1, characterized in that as the catalyst (s) use large-pore sulfocationic.

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