A catalyst for synthesizing dimeric isobutene and its application

Abstract

The present invention discloses a catalyst for synthesizing dimeric isobutene and its application, belonging to the technical field of petrochemical industry. The catalyst of the present invention is a WOxFeMOy multi-metal composite oxide solid acid with an Fe-based spinel structure, which is prepared by a hydrothermal method, a precipitation method, or a sol-gel method, and catalyzes the synthesis of dimeric isobutene in a reaction kettle / fixed bed. The synthesis method of the present invention has the advantages of simple process route, mild reaction conditions, and easy separation of the catalyst from the raw materials and products, and has good application prospects and industrial application potential in the field of petrochemical industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of petrochemical industry, and particularly relates to a catalyst for synthesizing dimeric isobutene and its application. Technical Background

[0002] Dimeric isobutene, also known as diisobutene, mainly consists of 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene. Diisobutene is mainly used in the production of octylphenol, isooctanol, etc. As an important organic chemical raw material, due to its C=C double bond, it can undergo self-polymerization or copolymerization reactions, addition reactions, halogenation reactions, alkylation reactions, carbonylation reactions, etc., to generate a series of fine chemical intermediates, which are widely used in the fields of plastic auxiliaries, rubber auxiliaries, lubricants, antioxidants, surfactants, synthetic detergents, etc.

[0003] Industrially, the isobutene dimerization process is usually used for the dimerization of C4 olefins to produce high-octane gasoline, and there is less research on the process of selectively dimerizing isobutene to obtain diisobutene as the target product. Usually, isobutene in mixed C4 is dimerized to form diisobutene under the action of an acid catalyst. At present, a variety of production methods of diisobutene have been developed, mainly including sulfuric acid extraction method, solid phosphoric acid method, molecular sieve method, resin method, etc. Among them, the industrialized production technologies include sulfuric acid extraction process, Bayer butene dimerization process, Diermersol X dimerization process, Octol butene dimerization process, Catstil catalytic distillation process, etc. Most of them aim to remove isobutene from mixed C4 or produce mixed C8 olefins (diisobutene, dimers of n-butene, and co-dimers of n- and isobutene, etc.) or isobutene oligomers. It is difficult to obtain high-purity diisobutene by the above processes, and the process is complex, and some processes have serious equipment corrosion.

[0004] Due to the many limitations caused by the use of liquid acid catalysts, people have focused their attention on the research of new solid acid catalysts. To date, the solid acid catalysts used in isobutene oligomerization reactions mainly include macroporous sulfonic acid resin catalysts, solid phosphoric acid catalysts, molecular sieve catalysts, solid superacid catalysts, oxides and composite oxides, etc. The solid phosphoric acid method is a commonly used method in industry. The raw material is isobutene in mixed C4. Using solid phosphoric acid as a catalyst, the dimerization reaction is carried out in a fixed bed reactor, and the selectivity can reach 75% (Yao Yaping, Yuan Meiqing, Xu Jing, etc., "T-49 New Solid Phosphoric Acid Catalyst and Its Application", "Petroleum Refining and Chemical Industry", 2000, 31(1) P10). Patent CN1810742A discloses a method for preparing diisobutene using free phosphoric acid as a catalyst, and the selectivity of diisobutene can reach more than 80%. Patent EP0371938A discloses a solid phosphoric acid catalyst using silica as a carrier, but the raw materials are not described in the patent and no specific dimer selectivity is given. Patent WO01046095A1 discloses an Hβ molecular sieve as a catalyst for the oligomerization of mixed C4 olefins to produce diisobutene, and it is found that the silicon-aluminum ratio has a great influence on the product distribution. When the Hβ silicon-aluminum ratio is 100, the conversion rate of isobutene is 100%, and the selectivity of diisobutene is 48%. Patent CN1087616A discloses a aluminosilicate catalyst for the dimerization of isobutene in C4 fractions, and the selectivity of the dimer is 65%. Gonzalez et al. (Catalysis Letters. 2006, 110:107-113) studied the effect of Ni 2+ modified zeolite molecular sieves on the dimerization of isobutene. The authors found that the acid amount of the molecular sieve can be increased after modification, but several molecular sieves investigated have problems such as rapid deactivation and very low conversion rates. Patent CN104395265A discloses a method for preparing isobutene by sugar fermentation and dimerizing it to produce diisobutene, but no specific selectivity results are given. Patent CN104815695B discloses a method for preparing diisobutene using a carbon nanotube-supported ionic liquid catalyst, but this method is too complex to be conducive to industrial application. It can be seen that the existing solid acid catalysts have problems such as low selectivity and complex separation processes, and further improvement is needed. There is no report on the related research of using Fe-based spinel ZnFe2O4 loaded with WO3 as a solid acid for this reaction. Summary of the Invention

[0005] Aiming at the deficiencies in the prior art, the present invention provides a catalyst for synthesizing diisobutene and its application. The catalyst of the present invention not only improves the conversion rate of diisobutene but also increases the selectivity of diisobutene. The reaction is milder, greener and more economical.

[0006] The present invention provides the following technical solutions:

[0007] A catalyst for synthesizing dimeric isobutene, wherein the catalyst is a WOxFeMOy multi-metal composite oxide solid acid with a Fe-based spinel structure, and M is one or more of transition metals Zr, Nb, Sn, Ga, Re, Zn, In, Al, Co, Ni, Mn, Mo, Ti, V, Cr.

[0008] Based on the above technical solution, further, based on the total mass of FeMOy, the content of WOx is 0.1 - 30%, and the molar ratio of Fe / M is 0.2:1 - 5:1.

[0009] Based on the above technical solution, further, based on the total mass of FeMOy, the content of WOx is 1 - 20%.

[0010] Based on the above technical solution, further, the WOxFeMOy multi-metal composite oxide solid acid with a Fe-based spinel structure is obtained by hydrothermal method, precipitation method, or sol-gel method.

[0011] On the other hand, the present invention provides a preparation method of the above catalyst for synthesizing dimeric isobutene, including the following steps:

[0012] 1) Weigh soluble salts of Fe and soluble salts of M, add deionized water and stir to dissolve to obtain solution A;

[0013] 2) Weigh soluble salts of W, add deionized water and stir to dissolve to obtain solution B;

[0014] 3) Slowly drop solution A into solution B under stirring, and obtain solution C after dropping;

[0015] 4) Weigh a certain amount of template agent, add deionized water and stir to dissolve, and slowly drop the obtained solution into solution C, and continue to stir for 2 - 6 h after dropping;

[0016] 5) Slowly drop a precipitant under stirring until the pH is 7 - 13, and continue to stir for 4 - 8 h;

[0017] 6) Transfer the solution obtained in step 5) to a hydrothermal kettle, and crystallize for 6 - 72 h in an environment of 70 - 180 °C;

[0018] 7) After crystallization, centrifuge and wash, and then wash with absolute ethanol 1 - 5 times;

[0019] 8) Vacuum dry at 30 - 80 °C to obtain a solid acid precursor;

[0020] 9) Calcine the solid acid precursor in an air atmosphere at 500 - 1300 °C for 2 - 10 h to obtain a solid acid catalyst WOxFeMOy.

[0021] Based on the above technical solution, further, the template agent in step 4) is one or more of CTAB, n-butanol, glycerol, P123, tetrapropylammonium hydroxide, and Tween.

[0022] Based on the above technical solution, further, the precipitating agent in step 5) is one or more of NH4HCO3, (NH4)2CO3, Na2CO3, NaOH, ammonia water, or urea.

[0023] Based on the above technical solution, further, the crystallization temperature in step 6) is 100 - 140 °C, and the crystallization time is 36 - 60 h.

[0024] Based on the above technical solution, further, the vacuum drying temperature in step 8) is 30 - 80 °C, and the vacuum drying time is 24 - 60 h.

[0025] Based on the above technical solution, further, the calcination temperature in step 9) is 700 - 900 °C, and the calcination time is 4 - 8 h.

[0026] The present invention also provides a method for synthesizing diisobutene from isobutene, using the above catalyst to catalyze the synthesis of diisobutene in a reaction kettle / fixed bed.

[0027] Based on the above technical solution, further, the reaction temperature is 40 - 100 °C, the reaction pressure is 0.1 - 5.0 MPa, the reaction time is 2 - 10 h, and the mass ratio of the catalyst to isobutene is 1:10 - 1:200.

[0028] Based on the above technical solution, further, one or more of polar substances such as methanol, tert-butanol, and MTBE are added as inhibitors during the reaction, and the mass ratio of the inhibitor to isobutene is 1:20 - 1:200.

[0029] Based on the above technical solution, further, the reaction pressure is the self-pressure of the system or the pressure generated by filling an inert gas.

[0030] Compared with the prior art, the present invention has the following advantages:

[0031] 1) The preparation process of the catalyst of the present invention is simple, has good repeatability, and has a very high selectivity for diisobutene;

[0032] 2) The reaction conditions of the present invention are mild and there is no equipment corrosion;

[0033] 3) The process of the present invention is simple and environmentally friendly, does not produce waste acid or waste water, does not require waste acid or waste water treatment, is a true atom-economic reaction, and reduces production costs. Specific embodiments

[0034] To make the above objects, features, and advantages of the present invention more apparent and understandable, the following provides a detailed description of the specific embodiments of the present invention. Many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0035] Example 1

[0036] Catalyst preparation:

[0037] Weigh 8.77 g of Zn(NO3)2·6H2O and 18.24 g of Fe(NO3)3·6H2O, add them to 100 ml of deionized water and stir to dissolve to obtain solution A; weigh 1.28 g of ammonium metatungstate, add it to 50 ml of deionized water and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring. After the addition is complete, obtain solution C; weigh 13.67 g of the template agent CTAB, add it to 50 mL of deionized water and stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition is complete, continue stirring for 4 h; slowly add a precipitant obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 100 °C for 48 h in an environment; after crystallization, centrifuge and wash multiple times, and then wash with anhydrous ethanol 3 times; dry in vacuo at 80 °C for 48 h to obtain a multi-metal solid acid precursor; calcine the multi-metal solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a multi-metal solid acid catalyst WOx / ZnFe2O4.

[0038] Reaction evaluation:

[0039] Put the catalyst, tert-butanol, and liquid isobutene into a reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, stir at a rate of 800 rpm to synthesize diisobutene; among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0040] Example 2

[0041] Catalyst preparation:

[0042] Weigh 3.28 g of Ga(NO3)3·9H2O, 8.77 g of Zn(NO3)3·6H2O, and 18.24 g of Fe(NO3)3·6H2O, add them to 100 ml of deionized water, and stir to dissolve to obtain solution A; weigh 1.54 g of ammonium metatungstate, add it to 50 ml of deionized water, and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring. After the addition is complete, obtain solution C; weigh 15.94 g of the template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition is complete, continue stirring for 4 h; slowly add a precipitant obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 100 °C for 48 h in an environment; after crystallization, centrifuge and wash multiple times, and then wash with anhydrous ethanol 3 times; dry in vacuum at 80 °C for 48 h to obtain a polymetallic solid acid precursor; calcine the polymetallic solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WOx / Ga2O3ZnFe2O4.

[0043] Reaction evaluation:

[0044] Put the catalyst, tert-butanol, and liquid isobutene into a reaction kettle, and synthesize diisobutene under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm; among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0045] Example 3

[0046] Catalyst preparation:

[0047] Weigh 3.14 g of ZrOCl2·8H2O, 8.77 g of Zn(NO3)3·6H2O, and 18.24 g of Fe(NO3)3·6H2O, add them to 100 ml of deionized water, and stir to dissolve to obtain solution A; weigh 1.54 g of ammonium metatungstate, add it to 50 ml of deionized water, and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring. After the addition is complete, obtain solution C; weigh 15.37 g of the template agent CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition is complete, continue stirring for 4 h; slowly add a precipitant obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 48 h; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash 3 times with anhydrous ethanol; dry in vacuo at 80 °C for 48 h to obtain a polymetallic solid acid precursor; calcine the polymetallic solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WOx / ZrO2ZnFe2O4.

[0048] Reaction evaluation:

[0049] Put the catalyst, tert-butanol, and liquid isobutene into a reaction kettle, and synthesize diisobutene under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm; among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0050] Example 4

[0051] Catalyst preparation:

[0052] Weigh 2.07 g of SnCl4, 8.77 g of Zn(NO3)3·6H2O, and 18.24 g of Fe(NO3)3·6H2O, add them to 100 ml of deionized water, and stir to dissolve to obtain solution A; weigh 1.54 g of ammonium metatungstate, add it to 50 ml of deionized water, and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring. After the addition is complete, obtain solution C; weigh 15.05 g of the template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition is complete, continue stirring for 4 h; slowly add a precipitant obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 48 h; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash 3 times with absolute ethanol; dry in vacuo at 80 °C for 48 h to obtain a polymetallic solid acid precursor; calcine the polymetallic solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WOx / SnO2ZnFe2O4.

[0053] Reaction evaluation:

[0054] Put the catalyst, tert-butanol, and liquid isobutene into a reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm, synthesize diisobutene; among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0055] Example 5

[0056] Catalyst preparation:

[0057] Weigh 5.17 g of C 10 H5NbO 20, 8.77 g of Zn(NO3)3·6H2O and 18.24 g of Fe(NO3)3·6H2O were added to 100 ml of deionized water and stirred until dissolved to obtain solution A; 1.54 g of ammonium metatungstate was weighed and added to 50 ml of deionized water and stirred until dissolved to obtain solution B; solution A was slowly added dropwise to solution B with stirring. After the addition was complete, solution C was obtained; 15.35 g of the template CTAB was weighed and added to 50 mL of deionized water and stirred until dissolved. The resulting solution was slowly added dropwise to solution C. After the addition was complete, stirring was continued for 4 h; 0.1 mol / l of a precipitant obtained by mixing (NH4)2CO3 and ammonia water in equal volumes was slowly added dropwise with stirring until the pH reached 13, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 48 h; after crystallization, centrifugation and washing were carried out multiple times, and then washed with anhydrous ethanol 3 times; vacuum drying was carried out at 80 °C for 48 h to obtain a polymetallic solid acid precursor; the polymetallic solid acid precursor was calcined in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WOx / NbO2ZnFe2O4.

[0058] Reaction evaluation:

[0059] The catalyst, tert-butanol, and liquid isobutene were put into a reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, the stirring rate was 800 rpm to synthesize diisobutene; among them, the mass of tert-butanol was 0.2 g, the mass of the catalyst was 1.0 g, the mass of isobutene was 20.0 g, and the mass ratio of the catalyst to isobutene was 1:20.

[0060] Example 6

[0061] Catalyst preparation:

[0062] Weigh 3.14 g of ZrOCl2·8H2O, 2.07 g of SnCl4, 8.77 g of Zn(NO3)3·6H2O, and 18.24 g of Fe(NO3)3·6H2O, add them to 100 ml of deionized water, and stir to dissolve to obtain solution A; weigh 1.83 g of ammonium metatungstate, add it to 50 ml of deionized water, and stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring. After the addition is complete, obtain solution C; weigh 16.83 g of the template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition is complete, continue stirring for 4 h; slowly add a precipitant prepared by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 48 h; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash 3 times with absolute ethanol; dry in vacuum at 80 °C for 48 h to obtain a polymetallic solid acid precursor; calcine the polymetallic solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WOx / ZrO2SnO2ZnFe2O4.

[0063] Reaction evaluation:

[0064] Put the catalyst, tert-butanol, and liquid isobutene into a reaction kettle, and synthesize diisobutene under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm; among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0065] Example 7

[0066] Catalyst preparation:

[0067] Weigh 5.17 g of C 10 H5NbO 20, 2.07 g of SnCl4, 8.77 g of Zn(NO3)3·6H2O, and 18.24 g of Fe(NO3)3·6H2O were added to 100 ml of deionized water and stirred until dissolved to obtain solution A; 1.83 g of ammonium metatungstate was weighed and added to 50 ml of deionized water and stirred until dissolved to obtain solution B; solution A was slowly added dropwise to solution B with stirring. After the addition was complete, solution C was obtained; 16.80 g of the template agent CTAB was weighed and added to 50 mL of deionized water and stirred until dissolved. The resulting solution was slowly added dropwise to solution C. After the addition was complete, stirring was continued for 4 h; a precipitating agent obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volumes was slowly added dropwise with stirring until the pH reached 8.5, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 48 h in an environment; after crystallization, centrifugation and washing were performed multiple times until there were no chloride ions, and then washing with absolute ethanol was performed 3 times; vacuum drying was carried out at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in an air atmosphere at 800 °C for 6 h to obtain a multi-metal solid acid catalyst WOx / NbO2SnO2ZnFe2O4.

[0068] Reaction evaluation:

[0069] The catalyst, tert-butanol, and liquid isobutene were put into a reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, the stirring rate was 800 rpm to synthesize diisobutene; among them, the mass of tert-butanol was 0.2 g, the mass of the catalyst was 1.0 g, the mass of isobutene was 20.0 g, and the mass ratio of the catalyst to isobutene was 1:20.

[0070] Comparative example 1

[0071] Catalyst preparation:

[0072] 8.77 g of Zn(NO3)3·6H2O and 18.24 g of Fe(NO3)3·6H2O were weighed and added to 100 ml of deionized water and stirred until dissolved to obtain solution A; 13.60 g of the template agent CTAB was weighed and added to 50 mL of deionized water and stirred until dissolved. The resulting solution was slowly added dropwise to solution A. After the addition was complete, stirring was continued for 4 h; a precipitating agent obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volumes was slowly added dropwise with stirring until the pH reached 8.5, and stirring was continued for 4 h; the solution was transferred to a hydrothermal autoclave with a liner and crystallized at 120 °C for 48 h in an environment; after crystallization, centrifugation and washing were performed multiple times, and then washing with absolute ethanol was performed 3 times; vacuum drying was carried out at 80 °C for 48 h to obtain a solid superacid precursor; the solid superacid precursor was calcined in an air atmosphere at 800 °C for 6 h to obtain a spinel-structured solid acid catalyst ZnFe2O4.

[0073] Reaction evaluation:

[0074] Put the catalyst, tert-butanol and liquid isobutene into the reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm, diisobutene is synthesized. Among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0075] Comparative Example 2

[0076] Catalyst preparation:

[0077] Weigh 8.77 g of Zn(NO3)3·6H2O and 18.24 g of Fe(NO3)3·6H2O, add them to 100 ml of deionized water and stir to dissolve to obtain solution A. Weigh 13.60 g of the template agent CTAB, add it to 50 mL of deionized water and stir to dissolve. The obtained solution is slowly added dropwise to solution A. After the addition is complete, continue stirring for 4 h. Slowly add dropwise the precipitant obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume to a pH of 8.5 under stirring, and continue stirring for 4 h. Transfer the solution to a hydrothermal kettle with a liner, and crystallize for 48 h in an environment of 120 °C. After crystallization, centrifuge and wash multiple times, and then wash with anhydrous ethanol 3 times. Vacuum dry at 80 °C for 48 h to obtain the solid acid precursor. Calcinate the solid superacid precursor in an air atmosphere at 600 °C for 6 h to obtain the spinel-structured solid acid catalyst ZnFeO4. Weigh 1.54 g of ammonium metatungstate, add it to 50 ml of deionized water and stir to dissolve. Add the above spinel to the solution and stir overnight, filter, wash with anhydrous ethanol three times, dry in an oven at 100 °C for 12 h, and calcinate the obtained solid in an air atmosphere at 800 °C for 4 h to obtain the spinel ZnFe2O4-supported solid acid catalyst WO x / ZnFe2O4(ip).

[0078] Reaction evaluation:

[0079] Put the catalyst, tert-butanol and liquid isobutene into the reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm, diisobutene is synthesized. Among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0080] Comparative Example 3

[0081] Catalyst preparation:

[0082] Weigh 10.36 g of SnCl4 and add it to 100 ml of deionized water, stir to dissolve to obtain solution A; weigh 1.28 g of ammonium metatungstate and add it to 50 ml of deionized water, stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring, and after the addition, obtain solution C; weigh 7.25 g of template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition, continue stirring for 4 h; slowly add a precipitant prepared by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 48 h in an environment; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash with anhydrous ethanol 3 times; dry in vacuum at 80 °C for 48 h to obtain a solid superacid precursor; calcine the solid superacid precursor in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WO x / SnO2.

[0083] Reaction evaluation:

[0084] Put the catalyst, tert-butanol and liquid isobutene into a reaction kettle, and synthesize diisobutene under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm; among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0085] Comparative example 4

[0086] Weigh 18.66 g of Fe(NO3)3·6H2O and add it to 100 ml of deionized water, stir to dissolve to obtain solution A; weigh 1.28 g of ammonium metatungstate and add it to 50 ml of deionized water, stir to dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring, and after the addition, obtain solution C; weigh 8.42 g of template CTAB, add it to 50 mL of deionized water, stir to dissolve, and slowly add the obtained solution dropwise to solution C. After the addition, continue stirring for 4 h; slowly add a precipitant prepared by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH reaches 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal autoclave with a liner, and crystallize at 120 °C for 72 h in an environment; after crystallization, centrifuge and wash multiple times, and then wash with anhydrous ethanol 3 times; dry in vacuum at 80 °C for 48 h to obtain a solid acid precursor; calcine the solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a solid acid catalyst WO x / Fe2O3.

[0087] Reaction evaluation:

[0088] Put the catalyst, tert-butanol and liquid isobutene into the reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm, diisobutene is synthesized. Among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0089] Comparative Example 5

[0090] Catalyst preparation:

[0091] Weigh 15.69 g of ZrOCl2·8H2O and add it to 100 ml of deionized water, stir and dissolve to obtain solution A; weigh 1.83 g of ammonium metatungstate and add it to 50 ml of deionized water, stir and dissolve to obtain solution B; slowly add solution A dropwise to solution B under stirring. After the addition is complete, obtain solution C; weigh 8.87 g of template agent CTAB, add it to 50 mL of deionized water, stir and dissolve, and slowly add the obtained solution dropwise to solution C. After the addition is complete, continue stirring for 4 h; slowly add a precipitant obtained by mixing 0.1 mol / l (NH4)2CO3 and ammonia water in equal volume dropwise under stirring until the pH is 8.5, and continue stirring for 4 h; transfer the solution to a hydrothermal kettle with a lining, and crystallize for 72 h in an environment of 120 °C; after crystallization, centrifuge and wash multiple times until there is no chloride ion, and then wash 3 times with anhydrous ethanol; dry in vacuum at 80 °C for 48 h to obtain a polymetallic solid acid precursor; calcine the polymetallic solid acid precursor in an air atmosphere at 800 °C for 6 h to obtain a polymetallic solid acid catalyst WO x / ZrO2.

[0092] Reaction evaluation:

[0093] Put the catalyst, tert-butanol and liquid isobutene into the reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm, diisobutene is synthesized. Among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0094] Comparative Example 6

[0095] Using Hβ (silica-alumina ratio 100) as the catalyst, put the catalyst, tert-butanol and liquid isobutene into the reaction kettle. Under the conditions of a temperature of 60 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, with a stirring rate of 800 rpm, diisobutene is synthesized. Among them, the mass of tert-butanol is 0.2 g, the mass of the catalyst is 1.0 g, the mass of isobutene is 20.0 g, and the mass ratio of the catalyst to isobutene is 1:20.

[0096] Comparative Example 7

[0097] Using HY (silica-alumina ratio 30) as the catalyst, the catalyst, tert-butanol, and liquid isobutene were introduced into the reaction kettle. Under the conditions of a temperature of 80 °C, a reaction time of 2 h, and a nitrogen pressure of 2.0 MPa, the stirring rate was 800 rpm to synthesize diisobutene. Among them, the mass of tert-butanol was 0.2 g, the mass of the catalyst was 1.0 g, the mass of isobutene was 20.0 g, and the mass ratio of the catalyst to isobutene was 1:20.

[0098] The diisobutene prepared in Examples 1-7 and Comparative Examples 1-7 was tested. The test standards were the conventional experiments and regulations in this field. The specific results are shown in Table 1, where:

[0099] Calculation of isobutene conversion rate:

[0100] Conversion rate = (n 进 -n 出 ) / n 进 *100%; n 进 n 出 represents the molar amounts of isobutene at the inlet and outlet;

[0101] Calculation of diisobutene selectivity:

[0102] Selectivity = n DIB / (n 进 -n 出 )*100%; n DIB represents the molar amount of diisobutene.

[0103] Table 1. Isobutene conversion rate and diisobutene selectivity of Examples 1-5 and Comparative Examples 1-7

[0104] Embodiment Catalyst Conversion rate % Selectivity % Example 1 <![CDATA[WO x / ZnFe2O4]]> 86.8 35.4 Example 2 <![CDATA[WO x / Ga2O3ZnFe2O4]]> 73.6 80.6 Example 3 <![CDATA[WO x / ZrO2ZnFe2O4]]> 75.0 82.5 Example 4 <![CDATA[WO x / SnO2ZnFe2O4]]> 73.3 85.3 Example 5 <![CDATA[WO x / NbO2ZnFe2O4]]> 78.4 88.8 Example 6 <![CDATA[WO x / ZrO2SnO2ZnFe2O4]]> 83.9 92.5 Example 7 <![CDATA[WO x / NbO2SnO2ZnFe2O4]]> 85.3 90.4 Comparative Example 1 <![CDATA[ZnF2eO4]]> 17.1 96.3 Comparative Example 2 <![CDATA[WO x / ZnFe2O4(ip)]]> 92.3 24.2 Comparative Example 3 <![CDATA[WO x / SnO2]]> 87.6 21.7 Comparative Example 4 <![CDATA[WO x / Fe2O3]]> 92.6 34.8 Comparative Example 5 <![CDATA[WO x / ZrO2]]> 95.5 20.4 Comparative Example 6 Hβ 93.6 42.7 Comparative Example 7 HY 94.4 37.6

[0105] From the results in Table 1, it can be seen that the catalyst of the present invention not only improves the conversion rate of diisobutene but also increases the selectivity of diisobutene. The reaction is milder, greener, and more economical.

[0106] The above-described embodiments are only preferred embodiments given to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are within the protection scope of the present invention. The protection scope of the present invention is subject to the claims.

Claims

1. A method for synthesizing diisobutene from isobutene, characterized in that, Catalytic synthesis of dimeric isobutene from isobutene in a reaction kettle / fixed bed using a catalyst; The catalysts are WOx / ZnFe2O4, WOx / Ga2O3ZnFe2O4, WOx / ZrO2ZnFe2O4, WOx / SnO2ZnFe2O4, WOx / NbO2ZnFe2O4, WOx / ZrO2SnO2ZnFe2O4, WOx / NbO2SnO2ZnFe2O4; The reaction temperature is 40 - 100 °C, the reaction pressure is 0.1 - 5.0 MPa, the reaction time is 2 - 10 h, and the mass ratio of the catalyst to isobutene is 1:10 - 1:200; The preparation method of the catalyst includes the following steps: 1) Weigh soluble salts of Fe and soluble salts of M, add deionized water and stir to dissolve to obtain solution A; M is one or more of Zr, Nb, Sn, Ga, Zn; 2) Weigh soluble salts of W, add deionized water and stir to dissolve to obtain solution B; 3) Slowly drop solution A into solution B with stirring, and obtain solution C after dropping; 4) Weigh a certain amount of template agent, add deionized water and stir to dissolve, and slowly drop the obtained solution into solution C, and continue to stir for 2 - 6 h after dropping; 5) Slowly drop the precipitant with stirring until the pH is 7 - 13, and continue to stir for 4 - 8 h; 6) Transfer the solution obtained in step 5) to a hydrothermal kettle, and crystallize for 6 - 72 h in an environment of 70 - 180 °C; 7) After crystallization, centrifuge and wash, and then wash with absolute ethanol 1 - 5 times; 8) Vacuum dry at 30 - 80 °C to obtain a solid acid precursor; 9) Calcinate the solid acid precursor in an air atmosphere at 500 - 1300 °C for 2 - 10 h to obtain a solid acid catalyst; The template agent described in step 4) is one or both of CTAB and tetrapropylammonium hydroxide.

2. The method according to claim 1, wherein One or more of polar substances methanol, tert-butanol, MTBE are added as inhibitors in the reaction, and the mass ratio of the inhibitor to isobutene is 1:20 - 1:

200.

3. The method according to claim 1, wherein The precipitant described in step 5) is one or more of NH4HCO3, (NH4)2CO3, Na2CO3, NaOH, ammonia water or urea.

4. The method according to claim 1, characterized in that, In step 6), the crystallization temperature is 100 - 140 °C and the crystallization time is 36 - 60 h; in step 8), the vacuum drying time is 24 - 60 h.

5. The method according to claim 1, characterized in that In step 9), the calcination temperature is 700 - 900 °C and the calcination time is 4 - 8 h.