Alkylation process

Abstract

The present application relates to the technical field of alkylation reaction, and discloses an alkylation method.The method comprises the following steps: under alkylation reaction conditions, linear olefin is reacted with aromatic hydrocarbon in the presence of an alkylation catalyst; wherein the alkylation catalyst comprises a rare earth modified molecular sieve and a binder, the rare earth modified molecular sieve comprises a molecular sieve and a rare earth element loaded on the molecular sieve, the E value of the rare earth modified molecular sieve is greater than 10%, and the C value is 0.3-2.8, wherein the E value represents the mass fraction of the rare earth element in the rare earth modified molecular sieve in terms of oxide, and the C value represents the ratio of the acid amount of B acid to L acid of the rare earth modified molecular sieve.The method of the present application can improve the reaction activity of the alkylation catalyst, inhibit the isomerization reaction of olefin, and further improve the linear degree of the product.

Description

Technical Field

[0001] This invention relates to the technical field of alkylation reactions, and more specifically to an alkylation method. Background Technology

[0002] Currently, linear alkylbenzenes are commonly used to prepare linear alkylbenzene sulfonates, which are mainly used as anionic surfactants. In existing technologies, liquid catalysts such as HF and AlCl3 are typically used as catalysts in the preparation of linear alkylbenzenes. However, liquid catalysts suffer from various drawbacks, including environmental pollution, severe equipment corrosion, difficulty in separating from the product, and high investment costs.

[0003] UOP and a Spanish oil company jointly developed a Detal solid acid process, which was industrialized in the mid-1990s. Because the Detal process uses an amorphous silica-alumina catalyst containing phosphorus (F), the process requires frequent regeneration, and F is lost during operation. The alkylation and catalyst regeneration processes are discontinuous, resulting in high operating costs. This has limited the promotion and development of the Detal solid acid process (Modern Chemical Industry, 2016, 45(2):373-375).

[0004] Existing research on molecular sieves for the catalytic synthesis of linear alkylbenzenes mainly focuses on Y-type molecular sieves, β-type molecular sieves and mordenite. The main problems they face are that the catalytic lifetime of molecular sieves is generally short and the linearity of the products is low (Bull.Korean Chem.Soc.,2001,22(9):1056-1058).

[0005] Patent application No. 200880111159.3 discloses a stratified zeolite catalyst for improving linearity in detergent alkylation, which enables the operating conditions to improve benzene alkylation and reduce the amount of alkyl isomerization.

[0006] Patent application number 201080056751.5 discloses a rare earth exchange catalyst for the alkylation of detergents, which can undergo cation exchange with rare earth elements to improve the alkylation of benzene. Summary of the Invention

[0007] The purpose of this invention is to overcome the problems of low catalyst reactivity and low linearity of the product in the alkylation process for preparing linear alkylbenzenes in the prior art, and to provide an alkylation method that can improve the reactivity of the alkylation catalyst and inhibit the olefin isomerization reaction, thereby improving the linearity of the product.

[0008] To achieve the above objectives, the present invention provides an alkylation method comprising: contacting a straight-chain olefin with an aromatic hydrocarbon in the presence of an alkylation catalyst under alkylation reaction conditions;

[0009] The alkylation catalyst comprises a modified molecular sieve and a binder. The rare earth modified molecular sieve comprises a molecular sieve and rare earth elements supported on the molecular sieve. The rare earth modified molecular sieve has an E value greater than 10% and a C value of 0.3-2.8. The E value represents the mass fraction of rare earth elements in the rare earth modified molecular sieve as oxides, and the C value represents the ratio of the amount of Brønsted acid to Lewis acid in the rare earth modified molecular sieve.

[0010] Preferably, the micropore specific surface area of ​​the rare earth modified molecular sieve is reduced by more than 7% compared with that of the molecular sieve, and more preferably by 7-28%.

[0011] Preferably, the micropore volume of the rare earth modified molecular sieve is reduced by more than 7% compared with that of the molecular sieve, and more preferably by 7-28%.

[0012] The inventors of this invention discovered in their research that the sites of both Brønsted (B) and Lewis (L) acids can serve as active sites for the catalytic synthesis of straight-chain alkylbenzenes. This method involves reacting straight-chain olefins with aromatics in the presence of an alkylation catalyst. The alkylation catalyst uses a rare-earth-modified molecular sieve combined with a binder. The rare-earth-modified molecular sieve is loaded with a large amount of rare-earth elements, and the distribution characteristics of Brønsted (B) and Lewis (L) acids in the modified molecular sieve are simultaneously controlled. Preferably, the specific surface area and micropore volume of the molecular sieve are simultaneously controlled. The confinement effect provided by the appropriate specific surface area and micropore volume of the molecular sieve is beneficial to improving the selectivity of straight-chain alkylbenzenes, thereby increasing the alkylation reaction activity, inhibiting the olefin isomerization reaction, and ultimately achieving the goal of increasing the straight-chain degree of the product. Attached Figure Description

[0013] Figure 1 This is a graph showing the trend of olefin conversion rate in Example 1 of the present invention;

[0014] Figure 2 This is a trend chart of the linearity of the product in Embodiment 1 of the present invention. Detailed Implementation

[0015] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0016] The present invention provides an alkylation method, wherein the method comprises: reacting a straight-chain olefin with an aromatic hydrocarbon in the presence of an alkylation catalyst under alkylation reaction conditions;

[0017] The alkylation catalyst comprises a rare earth modified molecular sieve and a binder. The rare earth modified molecular sieve comprises a molecular sieve and rare earth elements supported on the molecular sieve. The rare earth modified molecular sieve has an E value greater than 10% and a C value of 0.3-2.8. The E value represents the mass fraction of rare earth elements in the rare earth modified molecular sieve as oxides, and the C value represents the ratio of the amount of Brønsted acid to Lewis acid in the rare earth modified molecular sieve.

[0018] The alkylation method provided by this invention uses rare earth modified molecular sieves as the active component of the alkylation catalyst. The rare earth modified molecular sieve is loaded with rare earth elements to adjust the distribution of Brønsted acid and Lewis acid (preferably by controlling the micropore specific surface area and micropore volume of the rare earth modified molecular sieve). The confinement effect provided by the appropriate micropore specific surface area and micropore volume of the molecular sieve is beneficial to improving the selectivity of straight-chain alkylbenzenes, thereby improving the alkylation reaction activity, inhibiting olefin isomerization reaction, and improving the straight-chain degree of the product.

[0019] According to a preferred embodiment of the present invention, the E value of the rare earth modified molecular sieve is 16-25%, for example, it can be 16%, 16.5%, 17%, 17.5%, 18%, 18.5%, 19%, 19.5%, 20%, 20.5%, 21%, 21.5%, 22%, 22.5%, 23%, 23.5%, 24%, 24.5%, 25%, and any value between any two groups.

[0020] According to a preferred embodiment of the present invention, the C value of the rare earth modified molecular sieve is 1-2.5, for example, it can be 1, 1.1, 1.15, 1.2, 1.25, 1.3, 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, 1.75, 1.8, 1.85, 1.9, 1.95, 2, 2.05, 2.1, 2.15, 2.2, 2.25, 2.3, 2.35, 2.4, 2.45, 2.5, and any value between any two groups.

[0021] In this invention, by introducing rare earth elements to regulate the acid content of Brønsted acid and Lewis acid in the modified molecular sieve, synergistic catalysis by Brønsted acid and Lewis acid can be achieved, thereby improving catalytic activity.

[0022] In this invention, the "E value" is measured by XRF. The instrument used is a Rigaku Electric Industrial Co., Ltd. 3271 X-ray fluorescence spectrometer. The test conditions are: the anode target material of the X-ray tube is a rhodium target; the laser voltage is 50kV; and the laser current is 50mA.

[0023] In this invention, the "C value" is obtained through Py-IR measurement. Specifically, the 1540 cm⁻¹ value in the Py-IR spectrum is...-1 The characteristic peak at 1450 cm⁻¹ represents the characteristic peak of Brønsted acid. -1 The characteristic peak at this point represents the characteristic peak of L acid, with a desorption temperature of 200℃. The "C value" is the ratio of the peak area of ​​the characteristic peak of Brønsted acid to the peak area of ​​the characteristic peak of L acid.

[0024] According to a preferred embodiment of the present invention, the micropore specific surface area of ​​the rare earth modified molecular sieve is reduced by more than 7% compared with that of the molecular sieve, and more preferably by 7-28%.

[0025] According to a preferred embodiment of the present invention, the micropore volume of the rare earth modified molecular sieve is reduced by more than 7% compared with that of the molecular sieve, and more preferably by 7-28%.

[0026] By modifying the molecular sieve channels through the above preferred embodiments, the formation of isomers can be suppressed.

[0027] According to a preferred embodiment of the present invention, the microporous specific surface area of ​​the rare earth modified molecular sieve is 400-600 m². 2 / g, further preferably 450-550m 2 / g.

[0028] According to a preferred embodiment of the present invention, the micropore volume of the rare earth modified molecular sieve is 0.16-0.26 cm³. 3 / g, further preferably 0.18-0.24cm 3 / g.

[0029] According to a preferred embodiment of the present invention, the micropore specific surface area of ​​the molecular sieve without rare earth element modification is 620-680 m². 2 / g, micropore volume is 0.27-0.31cm³ 3 / g, compared to the unmodified molecular sieve, the modified molecular sieve of the present invention has a smaller micropore specific surface area and pore volume, and the molecular sieve pores are modified to suppress the formation of isomers.

[0030] In this invention, the microporous specific surface area and pore volume of both modified and unmodified molecular sieves were measured using the BET method. The instrument used was a Micromeritics ASAP2460 multi-station specific surface area and porosity analyzer. The testing procedure involved evacuating the sample to a vacuum of 330°C to 10... -3 The catalyst was kept at low temperature for 9 hours to remove adsorbed water and other impurities. The specific surface area and micropore volume of the sample were calculated using the BET (Brunauer-Emmett-Teller) method.

[0031] In this invention, there is no particular limitation on the type of rare earth modified molecular sieve. Preferably, the rare earth modified molecular sieve is a silica-alumina molecular sieve.

[0032] According to a preferred embodiment of the present invention, the silicon-to-aluminum molar ratio of the rare earth modified molecular sieve is 0.5-50, preferably 1-8. In this invention, it is understood that the silicon-to-aluminum molar ratio refers to the molar ratio of silicon atoms to aluminum atoms.

[0033] In this invention, the silicon-aluminum molar ratio remains essentially unchanged before and after molecular sieve modification, both satisfying the above-mentioned molar ratio range requirements.

[0034] In this invention, there is no particular limitation on the types of rare earth elements in the rare earth modified molecular sieve; all rare earth elements conventionally defined in the art are applicable to this invention. Preferably, the rare earth elements are selected from Sc, Y, and non-radioactive lanthanides.

[0035] According to a preferred embodiment of the present invention, the rare earth element is selected from at least one of Sc, Y, La, Ce, Pr, Nd, Sm and Yb, and more preferably La and / or Ce.

[0036] According to a preferred embodiment of the present invention, the method for preparing the rare earth modified molecular sieve includes:

[0037] (1) The molecular sieve is placed in a solution containing rare earth element compounds for ion exchange, followed by solid-liquid separation and drying, and then subjected to a first calcination. The above steps are repeated at least once to obtain the ion exchange product.

[0038] (2) The ion exchange product is optionally subjected to at least one second calcination, followed by at least one third calcination, so that the C value is 0.3-2.8, to obtain a rare earth modified molecular sieve; the C value represents the ratio of the amount of Brønsted acid to L-acid in the rare earth modified molecular sieve, and the E value of the rare earth modified molecular sieve is greater than 10%, where the E value represents the mass fraction of rare earth elements in the rare earth modified molecular sieve as oxides.

[0039] The inventors of this invention have made a creative discovery that rare earth modified molecular sieves can be prepared by combining multiple ion exchanges and calcination, which can adjust the acidity and pore size of the molecular sieve, thereby inhibiting the formation of reaction byproducts and improving the linearity of the product.

[0040] In this invention, by controlling the operation steps, conditions and the number of repetitions of each step in steps (1)-(2), the E value and C value in the rare earth modified molecular sieve are made to satisfy the above-mentioned E value being greater than 10% and C value being 0.3-2.8. In this invention, the preferred range of E value and C value (preferably, E value is 16-25% and C value is 1-2.5) and the determination method have been described in the foregoing content and will not be repeated here.

[0041] In this invention, there is no particular limitation on the type of molecular sieve mentioned in step (1), and all molecular sieves defined in the art are applicable to this invention. Preferably, in step (1), the molecular sieve is a silica-alumina molecular sieve.

[0042] According to a preferred embodiment of the present invention, in step (1), the silicon-to-aluminum molar ratio of the molecular sieve is 0.5-50, preferably 1-8. It is understood in this invention that the silicon-to-aluminum molar ratio refers to the molar ratio of silicon atoms to aluminum atoms.

[0043] According to a preferred embodiment of the present invention, in step (1), the molecular sieve is in the hydrogen form and / or ammonium form, more preferably in the hydrogen form. The advantage of this preferred embodiment is that it can provide the Brønsted acid sites required for the molecular sieve.

[0044] According to a preferred embodiment of the present invention, in step (1), the molecular sieve is selected from at least one of X-type molecular sieve, Y-type molecular sieve, β-type molecular sieve, mordenite and MCM-22 type molecular sieve, and is more preferably X-type molecular sieve and / or Y-type molecular sieve.

[0045] According to a preferred embodiment of the present invention, in step (1), the molecular sieve is a HY type molecular sieve.

[0046] In this invention, by selecting molecular sieves as raw materials, it is beneficial for the contact between aromatic hydrocarbons and straight-chain olefins, thereby improving the straight-chain degree of the target product.

[0047] In this invention, the types of rare earth elements mentioned in step (1) have been described above and will not be repeated here.

[0048] In this invention, the range of rare earth element compounds selected in step (1) is relatively wide. Preferably, the rare earth element compound in step (1) is selected from at least one of the nitrates, sulfates, and chlorides of the corresponding rare earth elements, and more preferably a nitrate, such as lanthanum nitrate, yttrium nitrate, cerium nitrate, etc.

[0049] According to a preferred embodiment of the present invention, in step (1), the concentration of the solution containing the rare earth element compound is 0.15-1.5 mol / L, preferably 0.3-0.8 mol / L. Through the above steps, it is beneficial for rare earth elements to be exchanged onto the molecular sieve, improving the exchange efficiency to achieve the target parameters, thereby increasing the linearity of the product.

[0050] According to a preferred embodiment of the present invention, in step (1), the volume ratio of the solution containing rare earth element compounds to the mass of the molecular sieve is 1-20 mL / g, preferably 3-9 mL / g.

[0051] According to a preferred embodiment of the present invention, in step (1), the ion exchange is carried out under stirring conditions.

[0052] In this invention, the conditions for ion exchange in step (1) are not particularly limited. Preferably, the conditions for ion exchange in step (1) include: a temperature of 60-125℃, a time of 0.3-1.4h, and a stirring rate of 200-510r / min; more preferably, a temperature of 75-95℃, a time of 0.7-1.1h, and a stirring rate of 300-450r / min. The advantage of this preferred embodiment is that it facilitates the contact and exchange between the molecular sieve and rare earth ions.

[0053] In this invention, the range of drying conditions in step (1) is relatively wide. Preferably, in step (1), the drying conditions include: a temperature of 60-200℃ and a time of 1-20h.

[0054] In this invention, a specific first calcination atmosphere and a first calcination atmosphere are selected to perform the first calcination and the second calcination, respectively. Preferably, in steps (1) and (2), the first calcination and the second calcination are each carried out independently under an alkaline atmosphere and a slightly positive pressure. Under the above conditions, the migration of cations in the molecular sieve can be promoted.

[0055] According to a preferred embodiment of the present invention, the alkaline atmosphere is provided by ammonia.

[0056] According to a preferred embodiment of the present invention, the concentration of the ammonia water is 0.05-0.5 mol / L, preferably 0.08-0.2 mol / L.

[0057] According to a preferred embodiment of the present invention, the ammonia water introduction rate is 0.02-5 mL / min compared to 50 g of the molecular sieve. It is understood that the introduction rate of the alkaline atmosphere (ammonia water) is proportional to the throughput of the molecular sieve; for example, as the throughput of the molecular sieve increases, the introduction rate of the alkaline atmosphere (ammonia water) can be increased proportionally. Those skilled in the art can select the appropriate rate based on actual needs.

[0058] According to a preferred embodiment of the present invention, in step (1), the first calcination conditions include: a temperature of 450-650℃, a time of 0.3-1.8h, and a pressure of 0.01-0.1MPa; preferably, a temperature of 500-580℃, a time of 0.6-1.5h, and a pressure of 0.01-0.06MPa, with the pressure measured using a gauge pressure gauge. Under these conditions, the migration of rare earth ions into the molecular sieve can be promoted, thereby achieving the regulation of rare earth elements.

[0059] According to a preferred embodiment of the present invention, step (1) is repeated 1-5 times, preferably 1-2 times. The advantage of this preferred embodiment is that it allows for more complete rare-earth ion exchange in the molecular sieve.

[0060] In this invention, the selection range for the second calcination conditions is relatively wide; they can be the same as or different from the selection range for the first calcination conditions. Under the above-mentioned preferred conditions, the molecular sieve can be further passivated to improve the stability of the rare earth modified molecular sieve.

[0061] According to a preferred embodiment of the present invention, in step (2), the conditions for the second calcination include: a temperature of 450-650°C, a time of 0.5-2h, and a pressure of 0.01-0.1MPa. Preferably, the temperature is 480-600°C, the time is 0.8-1.8h, and the pressure is 0.01-0.06MPa, with the pressure measured in gauge.

[0062] According to a preferred embodiment of the present invention, in step (2), the second roasting is repeated 1-5 times, preferably 1-2 times.

[0063] According to a preferred embodiment of the present invention, in step (2), the third calcination is carried out in an air atmosphere. Under the above preferred conditions, calcination in an air atmosphere can further modulate the migration degree of rare earth ions, thereby controlling the distribution of Brønsted acid and Lewis acid in the modified molecular sieve.

[0064] In this invention, there is no particular limitation on the air introduction rate in step (2). Preferably, in step (2), the air introduction rate is 100-1000 mL / min, and more preferably 250-750 mL / min.

[0065] According to a preferred embodiment of the present invention, in step (2), the conditions for the third calcination include: a temperature of 450-650°C, a time of 0.8-3h, and a pressure of 0.01-0.1MPa. Preferably, the temperature is 500-620°C, the time is 0.8-2h, and the pressure is 0.01-0.06MPa, with the pressure measured in gauge.

[0066] According to a preferred embodiment of the present invention, the third roasting in step (2) is repeated 1-5 times, preferably 1-2 times.

[0067] In this invention, a wide range of adhesive types can be selected. Preferably, the adhesive is a heat-resistant inorganic oxide.

[0068] According to a preferred embodiment of the present invention, the binder is selected from at least one of alumina, zirconium oxide, silicon dioxide and titanium dioxide, and is more preferably alumina.

[0069] In this invention, there is no particular limitation on the preparation method of the alkylation catalyst. A preparation method conventionally defined in the art can be selected, such as the extrusion molding method. In a preferred embodiment, the preparation method of the alkylation catalyst includes: mixing rare earth modified molecular sieve with binder and / or its precursor, water and optionally extrusion aid and adhesive solvent, molding, and then sequentially performing molding drying and molding calcination.

[0070] The types of rare earth modified molecular sieves and binders mentioned in this invention have been described above and will not be repeated here.

[0071] According to the method of the present invention, preferably, the binder precursor is selected from at least one of oxide sol, aluminum salt, silicate, titanium salt and zirconium salt.

[0072] According to a preferred embodiment of the present invention, the oxide sol includes at least one of silica sol, titanium sol, and zirconium sol.

[0073] According to a preferred embodiment of the present invention, the aluminum salt is selected from at least one of boehmite, aluminum chloride, and aluminum sulfate.

[0074] According to a preferred embodiment of the present invention, the silicate is at least one of sodium silicate, potassium silicate, and calcium silicate.

[0075] According to a preferred embodiment of the present invention, the titanium salt is titanium sulfate and / or titanium tetrachloride.

[0076] According to a preferred embodiment of the present invention, the zirconium salt is zirconium chloride and / or zirconium sulfate.

[0077] According to a preferred embodiment of the present invention, the average particle size of the adhesive is 0.005-200 μm, more preferably 30-150 μm.

[0078] According to a preferred embodiment of the present invention, the weight ratio of the rare earth modified molecular sieve to the binder and / or its precursor, on a dry basis, is 99:1-20:80, preferably 93:7-30:70, and more preferably 85:15-55:45.

[0079] In this invention, "on a dry basis" refers to the mass of a unit mass of catalyst after calcination at 600°C for 3 hours.

[0080] In this invention, there is no particular limitation on the type of extrusion aid; any extrusion aid conventionally defined in the art is applicable to this invention. Preferably, the extrusion aid is selected from at least one of guar gum powder, cellulose, and starch.

[0081] In this invention, there is no particular limitation on the amount of extrusion aid. Preferably, the amount of extrusion aid is 0-15 wt% of the total dry weight of the rare earth modified molecular sieve, binder and / or its precursor, and more preferably 1-5 wt%.

[0082] In this invention, there is no particular limitation on the type of adhesive solvent; adhesive solvents conventionally defined in the art are applicable to this invention. Preferably, the adhesive solvent is selected from at least one of citric acid, nitric acid, and phosphoric acid.

[0083] In this invention, there is no particular limitation on the amount of adhesive solvent used. Preferably, the amount of adhesive solvent used is 0-20 wt% of the total dry weight of the rare earth modified molecular sieve, binder and / or its precursor, and more preferably 1-7 wt%.

[0084] In this invention, the amount of water used is not particularly limited, as long as it is sufficient to ensure uniform mixing of the rare earth modified molecular sieve, binder, extrusion aid, and adhesive. Preferably, the amount of water used is 30-180 wt% of the total dry weight of the rare earth modified molecular sieve, binder, and / or its precursor, and more preferably 70-110 wt%.

[0085] In this invention, the molding and drying conditions are such that the dry basis weight of the mixed molded article after drying is 55-95 wt%, preferably 65-85 wt%.

[0086] In a preferred embodiment, the molding and drying conditions include a temperature of 80-220°C and a time of 2-24 hours.

[0087] In this invention, the selection range of molding and calcining conditions is relatively wide. Preferably, the molding and calcining conditions include: a temperature of 350-650℃ and a time of 0.5-8h; more preferably, a temperature of 450-600℃ and a time of 1-5h.

[0088] According to a preferred embodiment of the present invention, the straight-chain olefin is a mixture in which the unsaturated bond is located on the top carbon atom or one of the middle carbon atoms of the straight-chain olefin.

[0089] According to a preferred embodiment of the present invention, the straight-chain olefin has 8-22 carbon atoms, more preferably 11-17, and even more preferably 11-15. The advantage of this preferred embodiment is that it facilitates the formation of alkylation products.

[0090] According to a preferred embodiment of the present invention, the aromatic hydrocarbon is selected from at least one of benzene, toluene and ethylbenzene, preferably benzene.

[0091] According to a preferred embodiment of the present invention, the alkylation reaction is a liquid-phase reaction. The advantage of this preferred embodiment is that it increases the contact time between the reactants and the catalyst, allowing the reactants to react fully. In this invention, it is understood that the alkylation reaction is carried out in a liquid phase, and the pressure is always sufficient to ensure that the reaction proceeds in a single liquid phase. In this invention, "single liquid phase" refers to the fact that all reactants are in a liquid phase, and the reaction conditions are such that the reactants do not vaporize during the reaction.

[0092] According to a preferred embodiment of the present invention, the contact conditions include: a temperature of 60-260°C, a pressure of 0.5-9 MPa, a molar ratio of aromatics to straight-chain olefins of 5:1-70:1, and a feed straight-chain olefin mass hourly space velocity of 0.1-5 h⁻¹. -1 .

[0093] According to a preferred embodiment of the present invention, the contact reaction conditions include: a temperature of 70-200°C, a pressure of 2-4 MPa, a molar ratio of aromatics to straight-chain olefins of 6:1-60:1, and a feed straight-chain olefin mass hourly space velocity of 0.3-3 h⁻¹. -1 .

[0094] According to the method of the present invention, an alkylation catalyst containing rare earth modified molecular sieves is selected to improve the alkylation reaction activity and inhibit the olefin isomerization reaction, so as to improve the linearity of the product.

[0095] In the following embodiments, unless otherwise specified, all raw materials used are commercially available.

[0096] In the examples, the rare earth content of the modified molecular sieve was measured by XRF (calculated as the mass fraction of rare earth oxides), the ratio of Brønsted acid to Lewis acid in the modified molecular sieve was calculated by Py-IR measurement, and the micropore specific surface area and micropore volume of the modified molecular sieve were determined by BET.

[0097] Example 1

[0098] Preparation of rare earth modified molecular sieves:

[0099] (1) Prepare a 0.5 mol / L lanthanum nitrate solution, then mix it with HY molecular sieve (silicon-aluminum molar ratio of 3.13) and stir evenly. Heat and stir at 85℃ for 1 h at a stirring rate of 400 r / min. The volume ratio of lanthanum nitrate solution to HY molecular sieve mass is 3 mL / g. After heating, filter the slurry and dry the filter cake at 110℃ for 4 h.

[0100] (2) The filter cake was roasted at high temperature for 1 hour. The first roasting conditions were: temperature 560℃, pressure 0.02MPa, and 0.1mol / L ammonia water was introduced at a flow rate of 0.1mL / min.

[0101] (3) The calcined sample was mixed with 0.5 mol / L lanthanum nitrate solution and stirred evenly. The mixture was heated and stirred at 85°C for 1 h at a stirring rate of 400 r / min. After heating, the slurry was filtered and the filter cake was dried at 110°C for 4 h.

[0102] (4) The filter cake after the second drying is calcined at high temperature for 1 hour under the same calcination conditions as in step (2) to obtain the ion exchange product.

[0103] (5) The ion exchange product after calcination in step (4) is subjected to a second calcination under the same conditions as in step (2) for 1.5 h.

[0104] (6) The molecular sieve after calcination in step (5) is subjected to a third calcination at high temperature for 2 hours. The calcination conditions are: temperature 560℃, pressure 0.02MPa, and air is introduced at a flow rate of 500mL / min.

[0105] (7) The rare earth modified molecular sieve prepared above is numbered N1.

[0106] Rare earth modified molecular sieve N1 was analyzed by XRF, Py-IR and BET to obtain the mass fraction of rare earth elements loaded on the molecular sieve, the ratio of B acid to L acid, the decrease ratio of micropore specific surface area, the decrease ratio of micropore volume, the specific surface area and micropore volume of the molecular sieve, and the silicon-aluminum molar ratio. The results are shown in Table 1.

[0107] In Table 1, the mass fraction of rare earth elements in rare earth modified molecular sieves is represented by the E value, and the ratio of B acid content to L acid content in rare earth modified molecular sieves is represented by the C value.

[0108] Preparation of alkylation catalysts:

[0109] Rare earth modified molecular sieve sample N1 was mixed with boehmite (average particle size 100 μm, Sinopec Catalyst Co., Ltd.) at a dry weight ratio of 80:20. 3 wt% of guar gum powder and 3 wt% of nitric acid were added respectively (based on the total dry weight of the rare earth modified molecular sieve and boehmite). Based on the dry weight of the rare earth modified molecular sieve and boehmite, 100 wt% of deionized water based on the dry weight of the modified molecular sieve and boehmite was added. After mixing evenly, the mixture was extruded and dried at 110 °C for 4 h to make the dry weight of the dried mixture 65 wt%. Then, it was calcined in air at 550 °C for 4 h to obtain the alkylation catalyst.

[0110] Alkylation reaction:

[0111] The alkylation reaction of benzene with 1-dodecene was carried out in the presence of the above-mentioned alkylation catalyst at 130 °C and 2.5 MPa, with a 1-dodecene feed mass hourly space velocity of 0.708 h⁻¹. -1The molar ratio of benzene to 1-dodecene was 10. Under these reaction conditions, the conversion rate of 1-dodecene, the linearity of the product, and the selectivity for isoolefins are shown in Table 2. The trend of 1-dodecene conversion rate is shown in the graph below. Figure 1 As shown in the figure, the trend of product linearity is as follows: Figure 2 As shown.

[0112] Conversion rate of 1-dodecene (%) = (Amount of 1-dodecene before reaction - Amount of 1-dodecene after reaction) / Amount of 1-dodecene before reaction × 100%.

[0113] Isomeric olefin selectivity (%) = Amount of isomeric olefin after reaction / Amount of all reaction products × 100%;

[0114] Straight-chain degree (%) = Amount of straight-chain alkylbenzene after reaction / Amount of monoalkylbenzene after reaction × 100%.

[0115] Example 2

[0116] (1) Prepare a 0.8 mol / L lanthanum nitrate solution, then mix it with HY molecular sieve (silicon-aluminum molar ratio of 3.13) and heat and stir at 85℃ for 1 h at a stirring rate of 400 r / min. The volume ratio of lanthanum nitrate solution to HY molecular sieve mass is 3 mL / g. After heating, filter the slurry and dry the filter cake at 110℃ for 4 h.

[0117] (2) The filter cake was roasted at high temperature for 1.5 hours. The first roasting conditions were: temperature 580℃, pressure 0.06MPa, and 0.2mol / L ammonia water was introduced at a flow rate of 5mL / min.

[0118] (3) The calcined sample was mixed with 0.8 mol / L lanthanum nitrate solution and stirred evenly. The mixture was heated and stirred at 85°C for 1 h at a stirring rate of 400 r / min. After heating, the slurry was filtered and the filter cake was dried at 110°C for 4 h.

[0119] (4) The filter cake after the second drying is calcined at high temperature for 1.5 h under the same calcination conditions as in step (2) to obtain the ion exchange product.

[0120] (5) The ion exchange product after calcination in step (4) is subjected to a second calcination under the same conditions as in step (2) for 1.8 h.

[0121] (6) The molecular sieve after calcination in step (5) is subjected to a third calcination at high temperature for 2 hours. The calcination conditions are: temperature 620℃, pressure 0.02MPa, and air is introduced at a flow rate of 750mL / min.

[0122] (7) The rare earth modified molecular sieve prepared above is numbered N2.

[0123] Rare earth modified molecular sieve sample N2 and pseudoboehmite (average particle size 100 μm, Sinopec Catalyst Co., Ltd.) were mixed at a dry basis weight percentage of 85:15. 5 wt% of guar gum powder and 7 wt% of nitric acid were added respectively (based on the total dry basis weight of rare earth modified molecular sieve and pseudoboehmite). Based on the dry basis of rare earth modified molecular sieve and pseudoboehmite, 110 wt% of deionized water based on the dry basis of modified molecular sieve and pseudoboehmite was added. After mixing evenly, the mixture was extruded and dried at 110℃ for 4 h to make the dry basis weight of the dried mixture 65 wt%. Then, it was calcined in air at 600℃ for 5 h to obtain the alkylation catalyst.

[0124] In the preparation of straight-chain alkylbenzenes, the reaction temperature was replaced with 200℃, the pressure with 4 MPa, the molar ratio of benzene to 1-dodecene with 60, and the feed mass hourly space velocity of the straight-chain olefin was 3 h⁻¹. -1 .

[0125] In the alkylation reaction, the feedstock 1-dodecene is replaced with 1-pentadene.

[0126] Example 3

[0127] (1) Prepare a 0.3 mol / L lanthanum nitrate solution, then mix it with HY molecular sieve (silicon-aluminum molar ratio of 3.13) and stir evenly. Heat and stir at 85℃ for 1 h at a stirring rate of 400 r / min. The volume ratio of lanthanum nitrate solution to HY molecular sieve mass is 3 mL / g. After heating, filter the slurry and dry the filter cake at 110℃ for 4 h.

[0128] (2) The filter cake was roasted at high temperature for 0.6h. The first roasting conditions were: temperature 500℃, pressure 0.01MPa, and 0.08mol / L ammonia water was introduced at a flow rate of 0.02ml / min.

[0129] (3) The calcined sample was mixed with 0.3 mol / L lanthanum nitrate solution and stirred evenly. The mixture was heated and stirred at 85°C for 1 h at a stirring rate of 400 r / min. After heating, the slurry was filtered and the filter cake was dried at 110°C for 4 h.

[0130] (4) The filter cake after the second drying was calcined at high temperature for 0.6 h under the same calcination conditions as in step (2) to obtain the ion exchange product.

[0131] (5) The ion exchange product after calcination in step (4) is subjected to a second calcination under the same conditions as in step (2) for 0.8 h.

[0132] (6) The molecular sieve after calcination in step (5) is subjected to a third calcination at high temperature for 0.8 h. The calcination conditions are: temperature 500℃, pressure 0.02MPa, and air is introduced at a flow rate of 250mL / min.

[0133] (7) The rare earth modified molecular sieve prepared above is numbered N3.

[0134] Rare earth modified molecular sieve sample N3 and boehmite (average particle size 100 μm, Sinopec Catalyst Co., Ltd.) were mixed at a dry basis weight percentage of 55:45. 1 wt% of guar gum powder and 1 wt% of nitric acid were added respectively (based on the total dry basis weight of the rare earth modified molecular sieve and boehmite). Based on the dry basis of the rare earth modified molecular sieve and boehmite, 70 wt% of deionized water of the dry basis of the modified molecular sieve and boehmite was added. After mixing evenly, the mixture was extruded and dried at 110℃ for 4 h to make the dry basis weight of the dried mixture 65 wt%. Then, it was calcined in air at 450℃ for 1 h to obtain the alkylation catalyst.

[0135] In the preparation of straight-chain alkylbenzenes, the reaction temperature was replaced with 70℃, the pressure with 2MPa, the molar ratio of benzene to 1-dodecene with 6, and the feed space velocity of the straight-chain olefin was 0.3h. -1 .

[0136] In the alkylation reaction, the starting material 1-dodecene is replaced with 1-undecene.

[0137] Example 4

[0138] The method in Example 1 is the same, except that in the preparation of rare earth modified molecular sieve, the concentration of lanthanum nitrate solution in step (1) is replaced with 0.15 mol / L, and the concentration of lanthanum nitrate solution in step (3) is replaced with 0.15 mol / L.

[0139] The rare earth modified molecular sieve prepared above is designated as N4.

[0140] Example 5

[0141] The method in Example 1 is the same, except that in the process of preparing rare earth modified molecular sieve, the calcination temperature in step (2) is replaced with 550°C, the calcination temperature in step (5) is replaced with 500°C, and the calcination temperature in step (6) is replaced with 600°C.

[0142] The rare earth modified molecular sieve prepared above is designated as N5.

[0143] Example 6

[0144] The method in Example 1 is the same, except that in the process of preparing rare earth modified molecular sieve, the calcination temperature in step (2) is replaced with 450℃, the calcination temperature in step (5) is replaced with 450℃, and the calcination temperature in step (6) is replaced with 450℃.

[0145] The rare earth modified molecular sieve prepared above is designated as N6.

[0146] Example 7

[0147] The method in Example 1 is the same, except that in the process of preparing rare earth modified molecular sieve, the heating temperature in step (1) is replaced with 60°C and the heating temperature in step (3) is replaced with 60°C.

[0148] The rare earth modified molecular sieve prepared above is designated as N7.

[0149] Example 8

[0150] The method in Example 1 is the same, except that steps (3) and (4) are repeated twice during the preparation of rare earth modified molecular sieves.

[0151] The rare earth modified molecular sieve prepared above is designated as N8.

[0152] Example 9

[0153] The method is the same as in Example 1, except that in the preparation of rare earth modified molecular sieves, the lanthanum nitrate solution in step (1) is replaced with samarium nitrate solution, and the lanthanum nitrate solution in step (3) is replaced with samarium nitrate solution.

[0154] The rare earth modified molecular sieve prepared above is designated as N9.

[0155] Example 10

[0156] The method in Example 1 is the same, except that in the process of preparing rare earth modified molecular sieve, the flow rate of 0.1 mL / min for 0.1 mol / L ammonia water in step (2) is replaced by the flow rate of 500 mL / min for air as the calcination atmosphere.

[0157] The rare earth modified molecular sieve prepared above is designated as N10.

[0158] Example 11

[0159] The method is the same as in Example 1, except that in the preparation of linear alkylbenzenes, the raw material 1-dodecene is replaced with 1-octadecene.

[0160] Example 12

[0161] The method described in Example 1 is followed, except that the reaction temperature in the preparation of linear alkylbenzenes is replaced with 240°C, the pressure is replaced with 7 MPa, the molar ratio of benzene to 1-dodecene is replaced with 70, and the feed mass hourly space velocity of the linear olefin is 0.1 h⁻¹. -1 .

[0162] Comparative Example 1

[0163] The HY molecular sieve from Example 1 was used without rare earth modification. The resulting comparative molecular sieve was designated CN1.

[0164] Comparative Example 2

[0165] The method of Example 1 was followed, except that the concentration of the lanthanum nitrate solution in step (1) was replaced with 0.1 mol / L, and step (6) was omitted. The resulting comparative molecular sieve was designated CN2.

[0166] Table 1

[0167]

[0168]

[0169] As can be seen from Table 1, Example 1 has a larger E value and a C value in the range of 0.3-2.8 compared with Comparative Example 1 and Comparative Example 2, indicating that Example 1 can regulate the distribution of Brønsted acid and Lewis acid in the molecular sieve. The micropore specific surface area and micropore volume of Example 1 are smaller than those of Comparative Example 1 and Comparative Example 2, indicating that Example 1 can regulate the micropore specific surface area and micropore volume of the molecular sieve.

[0170] Table 2

[0171]

[0172]

[0173] As can be seen from Table 2, when the E and C values ​​of the modified molecular sieve are within the protection range, the solid acid catalyst prepared using it has a significant improvement on the linearity of the product.

[0174] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An alkylation method, characterized in that, The method includes: reacting a straight-chain olefin with an aromatic hydrocarbon in the presence of an alkylation catalyst under alkylation reaction conditions; The alkylation catalyst comprises a rare earth modified molecular sieve and a binder. The rare earth modified molecular sieve comprises a molecular sieve and rare earth elements supported on the molecular sieve. The rare earth modified molecular sieve has an E value of 16-25% and a C value of 1-2.

48. The E value represents the mass fraction of rare earth elements in the rare earth modified molecular sieve as oxides, and the C value represents the ratio of the amount of Brønsted acid to Lewis acid in the rare earth modified molecular sieve. The specific surface area of ​​the micropores in the rare earth modified molecular sieve is reduced by 15.11-28% compared to that of a regular molecular sieve. The micropore volume of the rare earth modified molecular sieve is reduced by 15.6-28% compared with that of a regular molecular sieve; The rare earth elements are selected from Sc, Y, and non-radioactive lanthanide elements; The rare earth modified molecular sieve is a silica-alumina molecular sieve; The C value was calculated using Py-IR, and the value at 1540 cm⁻¹ in the Py-IR spectrum is shown. -1 The characteristic peak at 1450 cm⁻¹ is a characteristic peak of Brønsted acid. -1 The characteristic peak at this point is the characteristic peak of L acid, the desorption temperature is 200℃, and the C value is the ratio of the peak area of ​​the characteristic peak of Br acid to the peak area of ​​the characteristic peak of L acid. The preparation method of the rare earth modified molecular sieve includes: (1) The molecular sieve is placed in a solution containing rare earth element compounds for ion exchange, followed by solid-liquid separation and drying, and then subjected to a first calcination. The above steps are repeated at least once to obtain the ion exchange product. (2) The ion exchange product is calcined at least once in the second stage, and then calcined at least once in the third stage to obtain rare earth modified molecular sieve; In steps (1) and (2), the first calcination and the second calcination are carried out independently under alkaline atmosphere and slightly positive pressure conditions.

2. The method according to claim 1, wherein, The rare earth modified molecular sieve has a microporous specific surface area of ​​400-600 m². 2 / g.

3. The method according to claim 2, wherein, The rare earth modified molecular sieve has a microporous specific surface area of ​​450-550 m². 2 / g.

4. The method according to claim 1, wherein, The rare earth modified molecular sieve has a micropore volume of 0.16-0.26 cm³. 3 / g.

5. The method according to claim 4, wherein, The rare earth modified molecular sieve has a micropore volume of 0.18-0.24 cm³. 3 / g.

6. The method according to claim 5, wherein, The silicon-aluminum molar ratio of the rare earth modified molecular sieve is 0.5-50.

7. The method according to claim 1, wherein, The rare earth element is selected from at least one of Sc, Y, La, Ce, Pr, Nd, Sm and Yb.

8. The method according to claim 7, wherein, The rare earth elements are La and / or Ce.

9. The method according to claim 1, wherein, The molecular sieve in step (1) is of hydrogen form and / or ammonium form.

10. The method according to claim 9, wherein, The molecular sieve in step (1) is of the hydrogen form.

11. The method according to claim 1, wherein, The molecular sieve in step (1) is an X-type molecular sieve and / or a Y-type molecular sieve.

12. The method according to claim 1, wherein, The rare earth element compound in step (1) is selected from at least one of the nitrate, sulfate and chloride salts of the corresponding rare earth element.

13. The method according to claim 12, wherein, In step (1), the concentration of the solution containing rare earth element compounds is 0.15-1.5 mol / L.

14. The method according to claim 13, wherein, In step (1), the concentration of the solution containing rare earth element compounds is 0.3-0.8 mol / L.

15. The method according to claim 1, wherein, In step (1), the volume ratio of the solution containing rare earth element compounds to the mass of the molecular sieve is 1-20 mL / g.

16. The method according to claim 15, wherein, In step (1), the volume ratio of the solution containing rare earth element compounds to the mass of the molecular sieve is 3-9 mL / g.

17. The method according to claim 1, wherein, In step (1), the ion exchange is carried out under stirring conditions.

18. The method according to claim 17, wherein, In step (1), the conditions for ion exchange include: a temperature of 60-125℃, a time of 0.3-1.4h, and a stirring rate of 200-510r / min.

19. The method according to claim 18, wherein, In step (1), the conditions for ion exchange include: a temperature of 75-95℃, a time of 0.7-1.1h, and a stirring rate of 300-450r / min.

20. The method according to claim 1, wherein, In step (1), the drying conditions include: a temperature of 60-200℃ and a time of 1-20h.

21. The method according to claim 1, wherein, The alkaline atmosphere is provided by ammonia.

22. The method according to claim 21, wherein, The concentration of the ammonia water is 0.05-0.5 mol / L.

23. The method according to claim 22, wherein, Compared to 50g of the molecular sieve, the ammonia water flow rate is 0.02-5mL / min.

24. The method according to claim 1, wherein, In step (1), the first calcination conditions include: a temperature of 450-650℃, a time of 0.3-1.8h, and a pressure of 0.01-0.1MPa, with the pressure measured by a gauge.

25. The method according to claim 24, wherein, In step (1), the first calcination conditions include: a temperature of 500-580℃, a time of 0.6-1.5h, and a pressure of 0.01-0.06MPa.

26. The method according to claim 1, wherein, The step (1) is repeated 1-5 times.

27. The method according to claim 26, wherein, The step (1) is repeated 1-2 times.

28. The method according to claim 1, wherein, In step (2), the conditions for the second calcination include: a temperature of 450-650℃, a time of 0.5-2h, and a pressure of 0.01-0.1MPa, with the pressure measured by a gauge.

29. The method according to claim 28, wherein, In step (2), the conditions for the second calcination include: a temperature of 480-600℃, a time of 0.8-1.8h, and a pressure of 0.01-0.06MPa.

30. The method according to claim 29, wherein, In step (2), the second roasting is repeated 1-5 times.

31. The method according to claim 30, wherein, In step (2), the second roasting is repeated 1-2 times.

32. The method according to claim 1, wherein, In step (2), the third calcination is carried out in an air atmosphere.

33. The method according to claim 32, wherein, In step (2), the air introduction rate is 100-1000 mL / min.

34. The method according to claim 1, wherein, In step (2), the conditions for the third calcination include: a temperature of 450-650℃, a time of 0.8-3h, and a pressure of 0.01-0.1MPa, with the pressure measured in gauge.

35. The method according to claim 34, wherein, In step (2), the conditions for the third calcination include: a temperature of 500-620℃, a time of 0.8-2h, and a pressure of 0.01-0.06MPa.

36. The method according to claim 1, wherein, The third roasting step (2) is repeated 1-5 times.

37. The method of claim 36, wherein, The third roasting step (2) is repeated 1-2 times.

38. The method according to claim 1, wherein, The adhesive is a heat-resistant inorganic oxide.

39. The method according to claim 38, wherein, The binder is selected from at least one of alumina, zirconium oxide, silicon dioxide, and titanium dioxide.

40. The method according to claim 39, wherein, The adhesive is aluminum oxide.

41. The method according to claim 1, wherein, The preparation method of the alkylation catalyst includes: mixing rare earth modified molecular sieve with binder precursor, water, extrusion aid, and adhesive solvent, molding, and then sequentially performing molding drying and molding calcination.

42. The method according to claim 41, wherein, On a dry basis, the weight ratio of the rare earth modified molecular sieve to the binder precursor is 99:1-20:

80.

43. The method according to claim 42, wherein, On a dry basis, the weight ratio of the rare earth modified molecular sieve to the binder precursor is 93:7-30:

70.

44. The method according to claim 43, wherein, On a dry basis, the weight ratio of the rare earth modified molecular sieve to the binder precursor is 85:15-55:

45.

45. The method according to claim 41, wherein, The extrusion aid is selected from at least one of guar gum powder, cellulose, and starch.

46. ​​The method according to claim 45, wherein, The amount of the extrusion aid is 1-5 wt% of the total dry weight of the rare earth modified molecular sieve and the binder precursor.

47. The method according to claim 41, wherein, The colloidal solvent is selected from at least one of citric acid, nitric acid, and phosphoric acid.

48. The method according to claim 47, wherein, The amount of the adhesive solvent is 1-7 wt% of the total dry weight of the rare earth modified molecular sieve and the binder precursor.

49. The method according to claim 41, wherein, The amount of water used is 30-180 wt% of the total dry weight of the rare earth modified molecular sieve and the binder precursor.

50. The method according to claim 49, wherein, The amount of water used is 70-110 wt% of the total dry weight of the rare earth modified molecular sieve and the binder precursor.

51. The method according to claim 41, wherein, The drying conditions for molding include: a temperature of 80-220℃ and a time of 2-24h.

52. The method according to claim 41, wherein, The conditions for molding and calcination include: a temperature of 350-650℃ and a time of 0.5-8h.

53. The method according to claim 52, wherein, The conditions for molding and calcination include: a temperature of 450-600℃ and a time of 1-5 hours.

54. The method according to claim 1, wherein, The straight-chain olefin is a mixture in which the unsaturated bond is located on the top carbon atom or one of the middle carbon atoms of the straight-chain olefin.

55. The method according to claim 54, wherein, The straight-chain olefin has 8-22 carbon atoms.

56. The method according to claim 55, wherein, The straight-chain olefin has 11-17 carbon atoms.

57. The method according to claim 56, wherein, The straight-chain olefin has 11-15 carbon atoms.

58. The method according to claim 1, wherein, The aromatic hydrocarbon is selected from at least one of benzene, toluene, and ethylbenzene.

59. The method according to claim 58, wherein, The aromatic hydrocarbon is benzene.

60. The method according to claim 1, wherein, The alkylation reaction is a liquid-phase reaction.

61. The method according to any one of claims 1 or 54-60, wherein, The contact reaction conditions include: a temperature of 60-260℃, a pressure of 0.5-9 MPa, a molar ratio of aromatics to straight-chain olefins of 5:1-70:1, and a feed straight-chain olefin mass hourly space velocity of 0.1-5 h⁻¹. -1 .

62. The method according to claim 61, wherein, The contact reaction conditions include: a temperature of 70-200℃, a pressure of 2-4 MPa, a molar ratio of aromatics to straight-chain olefins of 6:1-60:1, and a feed straight-chain olefin mass hourly space velocity of 0.3-3 h⁻¹. -1 .

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