RU2144018C1 - Method of preparing di-and trimers of c3-c5 alkenes and/or mixtures thereof with alcohols - Google Patents

Abstract

FIELD: petrochemistry. SUBSTANCE: alkenes or alkene-containing mixtures are subjected to liquid phase contacting with sulfoionite catalyst in H₊ from at elevated temperature followed by distillation of at least unreacted C₃-C₄ hydrocarbons and optionally the resulting alcohol(s). Water content in sulfocationite catalyst is maintained from 2 to 35% by weight of dry catalyst. Water is fed in molar ratio to hydrocarbons from 0.002 to 0.03:1, preferably from 0.01: 1 to 0.1:1. EFFECT: more efficient process and lower desactivation of the catalyst. 7 cl, 8 ex, 3 dwg, 1 tbl

Description

The invention relates to the production of high-octane gasoline components from C ₃ -C ₅ alkenes.

More specifically, the invention relates to the field of producing di- and trimers of C ₃ -C ₅ alkenes and / or mixtures thereof with alcohols and / or their hydrogenation products.

 Known methods for producing dimers or oligomers of alkenes by contacting alkene-containing mixtures with concentrated strong acids: sulfuric, hydrofluoric, alkyl and aryl sulfonic acids [F. Azinger, Chemistry and technology of monoolefins. -M.: Gostoptekhizdat, 1960, p. 285].

 The disadvantages of the method are the strong corrosiveness of the working environment and the receipt of a large amount of harmful waste.

 The known method [US-Pat, N 3658936, class. D 60-683.15, 1974] dimerization and polymerization of alkenes on catalysts representing a mineral acid (usually phosphoric acid) supported on a solid support such as silica gel or kieselguhr.

 The disadvantage of this method is the lack of a strong chemical bond between the deposited acid and a solid carrier, which leads to constant ablation of the acid, and, as a result, to a decrease in the activity of the catalyst and the occurrence of corrosion problems, especially when using strong acids.

The use of weaker phosphoric acid leads to the necessity of carrying out the process at a high temperature (170-210 ^o C), which leads to an increased consumption of energy, as well as to a relatively low selectivity for the production of dimers and increased formation of oligomers.

, снижающих продолжительность службы сульфоионитных катализаторов.There is also known a method [WO 86/05776 A1, 09.10.86], according to which at the same time hydration and oligomerization of one or more C ₃ -C ₆ alkenes are carried out under hydration conditions on an acidic hydrating catalyst and a reaction product containing alkenes oligomers, esters and alcohols is obtained . In this case, the molar ratio of water: alkene (s) from 1: 3 to 1-90 is maintained in the stream supplied to the catalyst. The disadvantage of this method is the mandatory receipt in the composition of the product of esters and alcohols, as well as the formation of a significant amount of oligomers

reducing the service life of sulfoionite catalysts.

 The known method [V.I. Isagulyants, A. M. Dessuki, Petrochemicals, petrochemical processes and oil refining: M.-L., Chemistry, 1964, vol. 51, p.115-118] oligomerization and polymerization of tertiary alkenes in the presence of sulfocationite, in particular dehydrated cation exchange resin KU-2, which is a sulfonated copolymer of styrene and divinylbenzene. The specified method can be considered as a prototype to the proposed method.

 The disadvantage of this method is that even at moderate temperatures the formation of low molecular weight polymers rather than dimers predominates. In this case, a rapid deactivation of the catalyst takes place.

We propose a method for producing di- and trimers of C ₃ -C ₅ alkenes and / or mixtures thereof with an admixture of alcohols by liquid-phase contacting of alkenes or alkene-containing mixtures with a sulfocationic catalyst in the H ⁺ form at elevated temperatures, followed by distillation of at least unreacted C ₃ - hydrocarbons C ₄ and, possibly, the alcohol (s) forming them, according to which the water content in the sulfoionite catalyst is from 2 to 35% by weight of the dry catalyst, preferably from 3 to 30%.

 As one of the options, a method is proposed according to which water in a molar ratio to the hydrocarbon feed from 0.002: 1 to 0.3: 1, preferably from 0.01: 1 to 0.1: 1, is supplied to the contact zone with the sulfoionite catalyst.

Alternatively, a method is proposed according to which isobutene and / or tert-pentenes contained in the initial mixture are subjected to predominant conversion into dimers, and the temperature is maintained at a temperature of 50-100 ^° C. in the reaction zone.

Also, as an option, a method is proposed according to which at least non-tertiary alkenes contained in the mixture are subjected to di- and trimerization and the temperature of 75-145 ^° C. is maintained in the reaction zone.

Alternatively, a method is proposed according to which, in mixtures containing at least tertiary and non-tertiary alkenes, tert-alkenes are initially primarily dimerized, the stream containing at least propene and / or n-butenes is distilled off and alkenes are di- and trimerized at a temperature of at least 25 ^o C higher than in the zone of predominant dimerization of tert-alkenes.

 Alternatively, a method is proposed according to which a stream containing alcohol (s) is distilled off from a mixture containing predominantly di- and trimers of alkenes, which is returned to the alkenes di- and trimerization zone (s) and / or removed from the system.

 Alternatively, a method is proposed according to which in the resulting mixture containing mainly di- and trimers of alkenes and tertiary (e) alcohol (s), the alcohol (s) is dehydrated in the presence of a sulfonate catalyst and the isobutene and / or isopentenes are distilled off .

 In the claims and the description of the invention, the terms "dimers" / "dimerization" and "trimers" / "trimeriation" are used for brevity and are understood not only as the formation of dimers and trimers from a specific substance (for example, isobutene dimers), but also as the formation of unlike molecule compounds (essentially sodimers and "co-trimers").

 The presence of a limited amount of water can significantly increase the selectivity of alkene dimerization with respect to tri- and oligomerization. Excess water in excess of the proposed leads to the suppression of reactions not only of oligomerization, but also of dimerization of alkenes due to the extremely high sorption of water on sulfocationite.

 In the process, reactors of various types can be used with various systems for dosing, flow distribution and heat removal.

 Alkenes oligomerization reactions are accompanied by the release of a large amount of heat. In this regard, when choosing a reactor design, an important factor is the organization of heat removal.

In the proposed method, heat can be removed in various ways, in particular, by cooling and recycling the obtained oligomerizate, by external cooling through the walls with water in tubular reactors, by using a series of adiabatic reactors with intermediate cooling between them, by evaporating part of the reaction masses etc. The most convenient from this point of view are the reaction-distillation reactor, in which raw materials are fed into the reaction zone. Oligomerizate is taken from the bottom of the reactor, and at least a vaporous stream of C ₃ -C ₄ hydrocarbons is removed from the top of the reactor, which, after condensation, partially returns to the top of the reactor as a reflux. Perhaps its combination with the preceding (s) once-through (s) reactor (s).

Various sulfocationionites in the H ⁺ form can be used as a catalyst, such as fine-grained, for example, KU-23, Amberlist-15, Amberlist-35, Purolight, etc., and molded sulfoionite catalysts, for example, KU-2FPP and KIF.

 It is preferable to use a fresh catalyst with the required water content, however, the initial loading of the catalyst with a different water content is acceptable, after which the concentration of water in the catalyst is brought to the optimum level during operation by controlling the amount of water supplied to the reactor.

 The creation of the required concentration of water can be achieved both by directly supplying water with food, and by initial loading of a wet catalyst, discrete introduction of water into the catalyst and / or by supplying, respectively, tertiary and / or secondary alcohol, at least partially decomposed on the catalyst in the reaction (n) zone (s) of dimerization and trimerization with the release of water.

 The use of the invention is illustrated by drawings and examples, which do not exhaust all possible embodiments of the invention, and other technical solutions are possible while observing the essence of the invention set forth in the claims and description.

 According to FIG. 1, the hydrocarbon mixture F and the flow of water B through the mixer CM are directed to a reactor P-1 containing a sulfocationite catalyst. Part of the output reaction stream is cooled and sent to the reactor inlet, and the rest of M is sent to a distillation column K-1, from which stream D containing unreacted hydrocarbons is removed as a distillate.

From the cube of the column, a stream W is withdrawn, containing mainly dimers, trimers, and also an admixture of tert-alkanol (s),
The stream W or a part thereof in order to reduce the unsaturation of hydrocarbons can be directed to the hydrogenation reactor G (shown by the dashed line), from which the stream P, containing mainly the hydrogenation products of dimers and trimers, is withdrawn.

According to FIG. 2, a hydrocarbon mixture F containing at least tert-alkenes and norm-alkenes, and water B are fed through a mixer CM to a reactor P-1 containing sulfocationite, where tert-alkenes are predominantly dimerized. In apparatus K-1, stream D ₁ , containing predominantly unreacted hydrocarbons, is distilled off from the reaction mixture M ₁ . Bottom of the apparatus K-1 output stream W, containing mainly dimers of tert-alkenes.

Stream D is sent to a P-2 reactor containing sulfocathionite (possibly after mixing with an additional stream of water in CM, where the normal alkenes are dimerized and / or trimerized. Stream M ₂ from P-2 is sent to a K-2 distillation column, where Product W _{2 is} distilled off unreacted hydrocarbons in the composition of D ₂ .

According to figure 3, after distillation of unreacted hydrocarbons from the reaction mixture M in the column K-1, the bottoms product W _{1 is} processed in two ways.

In Embodiment I, a D ₂ stream containing the resulting alcohol (s) is distilled off in column K-2, which is returned to the inlet of reactor P.

In option II, in the reaction-distillation apparatus of the Republic of Kazakhstan containing a sulfocationite catalyst, the formed tert-alkanol is dehydrated and a stream containing predominantly isoalkene (s) is discharged from above, and a stream W ₃ , containing mainly dimers and / or trimers, is withdrawn from the cube.

The streams W ₂ and W ₃ can be directed to hydrogenation to produce the corresponding saturated hydrocarbons.

In the examples used the following industrial catalysts:
Amberlist-15 - porous fine-grained (0.4-1.2 mm) sulfocationite based on a copolymer of styrene (80%) and divinylbenzene (20%), which had a static exchange capacity of СОЕ = 4.7 mEq • H ⁺ / g dry masses.

 Amberlist-35 - porous fine-grained (0.4-0.7 mm) sulfocationite based on a copolymer of styrene (80%) and divinylbenzene (20%), СОЕ = 5.2.

 KU-23 - porous fine-grained (0.3-1.2 mm) sulfocationite based on a copolymer of styrene (92%) and divinylbenzene (8%), СОЕ = 3.9.

 KU-2FPP - molded (in the form of rings with a height of ~ 12 mm, an outer diameter of ~ 11 mm and a wall thickness of ~ 2 mm), a porous sulfonitic catalyst obtained by mixing finely ground sulfonated copolymer of styrene and divinylbenzene with polypropylene, followed by extrusion molding.

All catalysts were initially obtained in a water-filled ("swollen") state and were subjected to partial vacuum drying at ~ 100 ^° C to a predetermined residual water content. In continuation of the work, the specified amount of water in the catalyst was maintained by supplying dissolved and / or insoluble and / or chemically bound (in the form of tert- and / or sec-alcohol (s) water, in an amount that compensates for its withdrawal from the stream leaving the reactor ( ami), including in chemically bonded (during hydration of alkenes) form. At the end of the experiment or in the interval between runs, samples were taken from at least the initial and final parts of the reaction zone, and also (in the part of experiments) from the middle part of the reaction zone and determined the water content in k atalizer.

 Examples 1-3.

 The characteristics of the main flows and technological parameters are given in table 1.

 2,4,4-trimethylpentene-1 (73 rel.%) And 2,4,4-trimethylpenten-2 (27 rel.%) Prevail in isobutene dimerization products, 3,4-dimethylhexenes - in n-butene dimerization products 2i-3 (~ 50 rel.%), 2,3-dimethylbutene-2 (65 rel.%) In the products of propene dimerization.

 Example 4

 Processing of the isobutane-isobutene mixture is carried out according to FIG. 3 (option I).

Processing in the reactor R-1 and the column K-1 is carried out analogously to example 1. In contrast to example 1, water in the reactor R-1 is supplied in an amount of 0.01 mol / mol of hydrocarbons. On top of the K-1 column, 0.57 t / t F of distillate containing 6% isobutene is withdrawn. Stream W _{1 is} subjected to rectification in a column of K-2. Distillate D _{2 is} removed from above in an amount of 0.06 t / t F, containing 58% tert-butanol and 42% dimers, which are recycled to the P-1 reactor. The water content in the catalyst in the reactor R-1 at the beginning of the catalyst layer is 10 wt. %, at the end of the catalyst layer - 15-20 wt.%. Bottom of the K-2 column, a W ₂ stream is withdrawn, containing mainly 2,4,4-trimethylpentenes-1 and 2 (89%) and partially isobutene trimers (10%).

 Example 5

 Processing of the isobutane-isobutene mixture (with 45% isobutene) is carried out according to FIG. 3 (option I), similar to that described in example 4.

In contrast to example 4, water in the reactor R-1 is supplied in an amount of 0.002 mol / mol of hydrocarbons. At the top of the K-2 column, a distillate stream is removed in an amount of 0.14 t / t F with a content of 48% tert-butanol, which is recycled to the inlet of the reaction system consisting of two successive reactors with intermediate cooling of the stream between them. The temperature in the reactor is 85-90 ^o C.

 The water content in the catalyst at the beginning of the first reactor is 2-3 wt.%, The water content in the catalyst at the outlet of the second reactor is 11-13%.

 On top of column 1, 0.52 t / t F of distillate D with a content of 4-5% isobutene is withdrawn. 0.48 t / t F of bottoms product containing 92% isobutene dimers (mainly 2,4,4-trimethylpentenes-1 and-2) and 8% isobutane trimers are removed from the bottom of the K-2 column.

 Example 6

Processing isobutane-isobutene mixture (with 45% isobutene) is carried out according to the scheme shown in figure 3 (option II). In contrast to that indicated in FIG. 3, the specification is that two successive reactors P-1 and P-2 are used (the latter in front of column K-1 in FIG. 3 not shown) with intermediate cooling. In the reactor R-1 serves water in an amount of 0.3 mol / mol of hydrocarbons. In P-1 and P-2, the temperature is maintained at 85-90 ^° C. At the beginning of the P-1 reactor, the concentration of water in the catalyst is 20 wt.%, At the end of the P-2 reactor is 35 wt.%.

The stream W ₁ from the cube of the K-1 column is fed into the reaction-distillation apparatus of the Republic of Kazakhstan, containing the KU-2FPP sulfonic ion catalyst and having a temperature of 85-90 ^o C. in the catalyst layer.

The isobutene stream D ₃ (0.024 t / t F) is discharged from above, which is returned to P-1, from the bottom is a stream of W ₃ containing mainly 2,4,4-trimethylpentenes-1 and -2 (~ 88%) and partially isobutene trimers (~ 12%).

 Example 7

The W stream obtained in Example 1 was catalytically hydrogenated in the presence of a palladium on alumina catalyst containing 1.8% palladium at 200 ^° C. 2,4,4-trimethylpentane (isooctane) predominated in the resulting product.

 Example 8

The processing of a C ₅ hydrocarbon mixture containing 30% tert-pentenes, 28% n-pentenes and 42% pentanes is carried out according to FIG. 1, without using a K-1 column. The dimerization unit uses fine-grained sulfocationion Amberlist-15 (4-6% water), a temperature of 70 ^o C. The result is a high-octane mixture containing 61% C ₅ hydrocarbons (including 1.7% tert-pentenes), 32 % dimers and co-dimers of pentenes (including 31.3% dimers of tert-pentenes) 4.4% hydrocarbons C ₁₅ (mainly trimers of tert-pentenes).

A part of the resulting mixture was hydrogenated on a nickel on kieselguhr catalyst at 185 ^° C. After hydrogenation, the mixture contained 61% C ₅ hydrocarbons (including 0.3% tert-pentenes), 0.9% dimers of tert-pentenes, 30.4% of their hydrogenation products and 4.4% of C ₁₅ hydrocarbons (mainly the hydrogenation products of tert-pentenes trimers).

Claims (7)

1. A method of producing di- and trimers of C ₃ -C ₅ alkenes and / or mixtures thereof with an admixture of alcohols by liquid-phase contacting of alkenes or alkene-containing mixtures with a sulfocationic catalyst in an H ⁺ form at elevated temperature, followed by distillation of at least unreacted C ₃ - hydrocarbons C ₄ and, possibly, the alcohol (s) forming it (s), characterized in that the water content in the sulfoionite catalyst is from 2 to 35% by weight of the dry catalyst, preferably from 3 to 30%.  2. The method according to claim 1, characterized in that the water in a molar ratio to the hydrocarbon feed from 0.002: 1 to 0.3: 1, preferably from 0.01: 1 to 0.1: 1, is supplied to the contact zone with the sulfoionite catalyst . 3. The method according to PP. 1 and 2, characterized in that the preferential conversion to dimers was subjected containing (f) camping in the initial mixture isobutene and / or tert-Pepto in the reaction zone is maintained at a temperature of 50 - 120 ^o C, preferably 60 - 100 ^o C. 4. The method according to PP. 1 and 2, characterized in that the di-and trimerization is subjected to at least non-tertiary alkenes contained in the mixture and the temperature of the reaction zone is maintained at 75-145 ^° C, preferably 85-130 ^° C. 5. The method according to claims 1 to 4, characterized in that in mixtures containing at least tertiary and non-tertiary alkenes, tert-alkenes are initially primarily dimerized, the stream containing at least propene and / or n-butenes is distilled off, and di- and trimerization of alkenes at a temperature of at least 25 ^o C higher than in the zone of predominant dimerization of tert-alkenes.  6. The method according to claims 1 to 5, characterized in that from the mixture containing predominantly di- and trimers of alkenes and / or products of their hydrogenation, a stream containing alcohol (s) is distilled off, which is returned to the zone (s) of di- and trimerization of alkenes and / or withdrawn from the system.  7. The method according to claims 1 to 6, characterized in that in the resulting mixture containing predominantly di- and trimers of alkenes and tertiary (e) alcohol (s), the alcohol (s) is dehydrated in the presence of a sulfonic ion catalyst and the generatrix (e) is distilled off ) isobutene and / or isopentenes.

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