CN106140258A

CN106140258A - A kind of catalyst with modified zsm-5 zeolite as carrier and preparation method thereof and its application in preparing isobutene

Info

Publication number: CN106140258A
Application number: CN201510135819.3A
Authority: CN
Inventors: 张信伟; 张舒冬; 李�杰; 孙晓丹; 倪向前; 尹泽群; 刘全杰; 张喜文
Original assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Current assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Priority date: 2015-03-27
Filing date: 2015-03-27
Publication date: 2016-11-23
Anticipated expiration: 2035-03-27
Also published as: CN106140258B

Abstract

The present invention provides a kind of catalyst with modified zsm-5 zeolite as carrier and preparation method thereof and its application in preparing isobutene.The preparation method of described catalyst, including following process: Hydrogen ZSM-5 molecular sieve carrier is carried out aqueous slkali, acid solution and magnesium salt solution impregnation process by (1) respectively；(2) zinc oxide is introduced in the Hydrogen ZSM-5 molecular sieve carrier after processing；(3) the Hydrogen ZSM-5 molecular sieve carrier after introducing zinc oxide is carried out bromination process, bromination is 0.5%-20% to zinc oxide weight content in catalyst, it is preferably 1%-15%, more preferably 1%-9%, zinc bromide weight content is 10%-50%, it is preferably 15%-45%, more preferably 18%-39%.Catalyst prepared by the method can significantly improve the selectivity of isobutene..

Description

A kind of catalyst with modified zsm-5 zeolite as carrier and preparation method thereof and its application in preparing isobutene

Technical field

The present invention relates to a kind of catalyst with modified zsm-5 zeolite as carrier and preparation method thereof and its application in preparing isobutene.

Background technology

Isobutene. is a kind of important basic organic chemical industry raw material, and its derived product is numerous, and vertical industry chain is complicated, and consumption structure is diversified trend.Multiple high value-added product can be prepared for raw material, such as: multiple Organic Chemicals and the fine chemistry products such as butyl rubber, polyisobutylene, methyl tertiary butyl ether(MTBE), isoprene and lucite with isobutene..Owing to the market scale of isobutene. downstream product constantly expands, its imbalance between supply and demand will gradually highlight, and particularly under the background of petroleum resources exhaustion day by day, the yield of isobutene. has become the critical bottleneck of restriction downstream industry development.Therefore, the isobutene. syntheti c route of exploitation Non oil-based route, extremely the most urgent.

Methane is the main component of natural gas, the important research content during therefore methane trans-utilization just becomes gas chemical industry's technology.The most in recent years, under the overall background that shale gas develops, if it is possible to realize producing isobutene. from methane, a new approach will be provided for obtaining isobutene..But methane stable in properties, the most easily-activated, become the bottleneck of methane chemical utilization.The most many researcheres carry out methane activation, Study on Transformation, among these, the technology that methane converts after halogen functional groupization more one after another, are expected to become the important breakthrough mouth solving a methane transformation technology difficult problem.

Many chemical products can be prepared from halide.Chinese patent CN 101041609A, CN 101284232A disclose one by methane at oxygen and HBr/H₂Being converted into bromomethane under the effect of O, then bromomethane reacts the method generating C3 ~ C13 mixing high-carbon hydrocarbon further, and the hydrocarbon selective of more than C5 is 70%.Wherein, HBr for methane bromination, then discharges in first reactor in second reactor, recovered after be used further in back reaction, it is achieved the recycling of HBr.(CN 102527427A, the Jieli such as Wang Ye He, Ting Xu, Zhihui Wang, et.al. Angew. Chem. Int. Ed. 2012,51,2438-2442) modified molecular sieve catalyst disclosing a kind of halide propylene and preparation method thereof.By using fluorochemical moditied processing molecular sieve, obtaining a kind of containing appropriate microporous structure and the catalyst of acidity, this catalyst can effectively be catalyzed halide and be converted into the reaction of propylene.Prepared catalyst one way bromomethane conversion ratio in the reaction that bromomethane is preparing propylene transformed is 35 ~ 99%, and the selectivity of propylene is 27 ~ 70%；In the reaction that chloromethanes is preparing propylene transformed, one way methyl chloride conversion rate is 30 ~ 99%, and the selectivity of propylene is 15 ~ 70%.Ivan M. Lorkovic et al. (Ivan M. Lorkovic, Aysen Yilmaz, Gurkan A. Yilmaz, et al. Catalysis Today, 2004,98,317-322) it is also proposed that generate bromo-hydrocarbons with bromine with the alkane reaction in natural gas, then on metal oxide catalyst, bromo-hydrocarbons is converted into dimethyl ether, methanol and metal bromide, obtain metal-oxide after metal bromide oxygen recovery and discharge simple substance bromine, completing the circulation of bromine.

It is mainly methanol, dimethyl ether, acetic acid, higher hydrocarbons, ethylene and propylene etc. currently, with respect to purpose product in the existing document that halide converts.In the technology with the low-carbon alkene of relatively high added value as target product, single selectivity of product is the highest, not yet finds the relevant report of bromomethane high selectivity isobutene..

Summary of the invention

For the deficiencies in the prior art, the present invention provides a kind of catalyst with modified zsm-5 zeolite as carrier and preparation method thereof and its application in preparing isobutene.

The preparation method of a kind of catalyst with modified zsm-5 zeolite as carrier, including following process: Hydrogen ZSM-5 molecular sieve carrier is carried out aqueous slkali, acid solution and magnesium salt solution impregnation process by (1) respectively；(2) zinc oxide is introduced in the Hydrogen ZSM-5 molecular sieve carrier after processing；(3) the Hydrogen ZSM-5 molecular sieve carrier after introducing zinc oxide is carried out bromination process, bromination is 0.5%-20% to zinc oxide weight content in catalyst, it is preferably 1%-15%, more preferably 1%-9%, zinc bromide weight content is 10%-50%, it is preferably 15%-45%, more preferably 18%-39%.

In above-mentioned preparation method step (1), described Hydrogen ZSM-5 molecular sieve carrier can be existing commercial product, it is also possible to prepare by those skilled in the art's well-known process.Suitable particle shape can be made or be chosen to carrier according to the needs used, and as made bar shaped, sheet shape, cylindricality, spherical etc., shaping can be carried out by this area general knowledge.

In above-mentioned preparation method step (1), impregnation process process is as follows: by Hydrogen ZSM-5 molecular sieve carrier, add in aqueous slkali by the liquid-solid ratio of 5mL/g-25mL/g, preferably liquid-solid ratio is 10mL/g-20mL/g, 0.5h-1.5h is stirred in room temperature to 80 DEG C, solid-liquid separation, gained solid is at 80 DEG C of-120 DEG C of dry 6h-12h；By dried sample, adding in acid solution by the liquid-solid ratio of 10mL/g-50mL/g, preferably liquid-solid ratio is 20mL/g-40mL/g, 1h-3h is stirred in 30 DEG C to 70 DEG C, solid-liquid separation, gained solid is at 80 DEG C of-120 DEG C of dry 6h-12h, then at 450 DEG C-650 DEG C roasting 4h-8h；Roasting sample is joined in the magnesium salt solution containing certain mass mark, in the ratio mixing adding 1mL-5mL magnesium salt solution in every gram of ZSM-5 molecular sieve, stand 4h-12h, preferably 6h-10h, 80 DEG C of-120 DEG C of dry 6h-12h, then at 450 DEG C-650 DEG C roasting 4h-8h, obtain modified ZSM-5 molecular sieve carrier.Above-mentioned aqueous slkali can be NaOH, KOH or Na₂CO₃One or more in aqueous solution, the concentration of aqueous slkali is 0.1mol/L-2mol/L, preferably 0.5mol/L-1.5mol/L；Acid solution can be one or more in hydrochloric acid, nitric acid or sulfuric acid solution, and the concentration of acid solution is 0.1mol/L-5mol/L, preferably 0.5mol/L-2.5mol/L；In the ZSM-5 molecular sieve carrier of described modification, magnesium counts weight content in the carrier as 0.5%-10% with element, preferably 1%-5%.

In above-mentioned preparation method step (2), described zinc oxide is introduced to the method that the method for modified hydrogen ZSM-5 molecular sieve carrier is well known to those skilled in the art, as impregnation method can be used to introduce.Concrete grammar is as follows: uses the Hydrogen ZSM-5 molecular sieve carrier that zinc solution dipping is modified, obtains bromomethane preparing isobutene catalyst precarsor after drying, roasting.Described drying condition is, temperature 60 C-150 DEG C, preferably 80 DEG C-120 DEG C；Time is 1h-24h, preferably 4h-8h；Can be vacuum drying time dry, it is also possible to for being dried under the conditions of inert gas shielding, it is also possible to be dried in air atmosphere.Described roasting condition is, temperature 200 DEG C-800 DEG C, preferably 400 DEG C-600 DEG C；Time is 1h-24h, preferably 4h-8h；It can be roasting under the conditions of inert gas shielding during roasting, it is also possible to roasting in air atmosphere.In said method, zinc salt can be inorganic salt, it is also possible to for one or more in organic salt, preferably nitrate, hydrochlorate, acetate, citrate.

In above-mentioned preparation method step (3), described bromination processes, and refers to use gas phase bromine-containing compound to process the sample of load zinc oxide.Bromine-containing compound refers to one or more in bromomethane, methylene bromide, bromoform, preferably bromomethane.Gas phase bromine-containing compound can also be used to carry out bromination process with the mixed gas of noble gas, and when using mixed gas bromination to process, bromomethane volumetric concentration is not less than 20%, preferably not less than 30%.Concrete bromination process is as follows: be placed in continuous fixed bed reactor by the sample of load zinc oxide, 150 DEG C-400 DEG C it are warming up under inert atmosphere, preferably 180 DEG C-350 DEG C, more preferably 200 DEG C-300 DEG C, being passed through gas phase bromine-containing compound gas, gas space velocity is 50h^-1-1000 h^-1, preferably 100h^-1-500h^-1；Can carry out at normal pressure during process, it is also possible to carry out under a certain pressure, system pressure is 0.1MPa-0.5MPa(absolute pressure), preferably 0.1MPa-0.3MPa(absolute pressure), the process time is 0.5h-8h, preferably 1h-4h.

In above-mentioned preparation method step (3), involved noble gas is the gas that nitrogen, argon, helium etc. do not occur chemical reaction under the conditions of involved in the present invention, preferably nitrogen.

A kind of catalyst using said method to prepare, described catalyst is made up of zinc oxide, zinc bromide and modified zsm-5 zeolite carrier, based on the weight content of catalyst, zinc oxide content is 0.5%-20%, it is preferably 1%-15%, more preferably 1%-9%, zinc bromide content is 10%-50%, being preferably 15%-45%, more preferably 18%-39%, modified zsm-5 zeolite vector contg is 40%-90%, it is preferably 50%-85%, more preferably 55%-80%, ZSM-5 molecular sieve carrier silica alumina ratio is 20 ~ 200, preferably 50 ~ 150.

In catalyst of the present invention, less than 450 DEG C total acid content (NH₃-TPD) it is 0.5mmol/g-1.3mmol/g, preferably 0.6mmol/g-1.2mmol/g, further preferred 0.7mmol-1.1mmol/g, the acid content of 250 DEG C-350 DEG C accounts for the 20%-90% of less than 450 DEG C total acid contents, preferably 30%-80%, further preferred 40%-80%.

The application in preparing isobutene of the above-mentioned ZSM-5 molecular sieve with the modification catalyst as carrier, hydrogen reducing activation is carried out including to catalyst, making the content of halogen in catalyst is the 20%-90% of total halogen content in reduction procatalyst, then the catalyst after making halide activate with above-mentioned hydrogen reducing contacts, to prepare isobutene..

In above-mentioned application, the condition of described hydrogen reducing activation makes the content of halogen in catalyst be preferably the 30%-80%, further preferred 40%-80% of total halogen content in reduction procatalyst.

In above-mentioned application, the mode of described hydrogen reducing activation includes under an inert atmosphere by catalyzer temperature-elevating to 300 DEG C-600 DEG C；Then passing to air speed is 200h^-1-2000h^-1Hydrogen or the mixed gas of hydrogen and noble gas, keep 2h-16h at 0.1MPa-0.5MPa, in mixed gas, hydrogen volume percentage composition is 10%-95%；Preferably, 350 DEG C-550 DEG C it are warming up to；Then passing to air speed is 500h^-1-1000h^-1Hydrogen or the mixed gas of hydrogen and noble gas, keep 4h-8h at 0.1MPa-0.3MPa, in described mixed gas, hydrogen volume percentage composition is 30%-90%.

In above-mentioned application, described halide can be one or more in one or more in a halide, methylene halide, three halides, preferably bromomethane, methylene bromide, bromoform.

In above-mentioned application, the condition of described contact includes that reaction temperature is 150 DEG C-350 DEG C；Reaction pressure is 0.1MPa-5MPa；Air speed is 50h^-1-1000h^-1；It is highly preferred that reaction temperature is 180 DEG C-300 DEG C more preferably 200-270 DEG C；Reaction pressure is 0.1MPa-3MPa；Air speed is 200h^-1-500h^-1。

A kind of detailed description of the invention in above-mentioned application, including under inert atmosphere by catalyzer temperature-elevating to 300 DEG C-600 DEG C, preferably 350 DEG C-550 DEG C；Then passing to air speed is 200h^-1-2000h^-1, preferably 500h^-1-1000h^-1Hydrogen or the mixed gas of hydrogen and noble gas, in 0.1MPa-0.5MPa(absolute pressure), preferably 0.1MPa-0.3MPa(absolute pressure) process 2h-16h, preferably 4h-8h after, be down to reaction temperature and be passed through halide and react.In described gaseous mixture, hydrogen volume percentage composition is 10%-95%, preferably 30%-90%, more preferably 50%-90%.

In above-mentioned application, raw material can also be the mixed gas of halide and noble gas, and in mixed gas, the volumetric concentration of halide is 10%-90%, preferably 30%-80%.

Noble gas involved in above-mentioned application is the gas that nitrogen, argon, helium etc. do not occur chemical reaction under the conditions of involved in the present invention, preferably nitrogen.

In above-mentioned application, the reaction of halide preparing isobutene can be carried out, such as fixed bed, fluid bed, fixed fluidized bed, moving bed, the reactor of the form such as slurry bed system or ebullated bed, preferably fixed bed, fluidized-bed reactor in existing any form reactor.

Compared with prior art, bromomethane height can be optionally converted into isobutene. by the catalyst that prepared by the present invention.Carry out bromomethane by the inventive method and convert preparing isobutene reaction, bromomethane conversion ratio more than 90%, selective isobutene more than 55%.The present invention relates to bromomethane conversion preparing isobutene method for preparing catalyst simple, it is easy to industrialization.Bromomethane of the present invention converts preparing isobutene method and has reaction condition gentleness, selectivity of product advantages of higher, easily realizes industrialization, and application prospect is boundless.

Detailed description of the invention

Further illustrate technology contents and the effect of the present invention below in conjunction with embodiment, but be not so limited the present invention.

In following example and comparative example, acidimetric estimation uses NH₃-TPD method, the INSTRUMENT MODEL of employing is MICROMERITICS company of U.S. AutoChem 2920 chemical adsorption instruments, concrete to measure process as follows: sample being cooled to 150 DEG C by helium purge after 1 hour at 450 DEG C, introduces the mixed gas of ammonia and helium, ammonia volume content 10%, Pulse adsorption reaches balance for five times；Helium purge 2 hours, then carries out ammonia with the programming rate temperature programming of 10 DEG C/min and is desorbed to 450 DEG C；Ammonia after desorption uses the detection of TCD detector, quantitative Analysis catalyst surface acid amount.

Embodiment 1

Weigh 30g Hydrogen ZSM-5 molecular sieve (silica alumina ratio 50) carrier, be dipped in the KOH aqueous solution that 600mL concentration is 0.5 mol/L, under room temperature, stir 1.5h, then solid-liquid separation, 120 DEG C of dry 6h；Again dried sample is dipped in the aqueous solution of nitric acid that 1200mL concentration is 0.5 mol/L, at 50 DEG C, stirs 2h, then solid-liquid separation, 100 DEG C of dry 9h, 550 DEG C of roasting 6h.Weigh the sample after 20g roasting, join in the magnesium nitrate solution that 83mL concentration is 1mol/L, stand 12h, then at 120 DEG C of dry 12h, at 550 DEG C of roasting 6h, obtain the modified zsm-5 zeolite that content of magnesium is 5%.

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 80 DEG C of dry 8h, 600 DEG C of roasting 4h, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor, treatment conditions are 250 DEG C, 0.2MPa(absolute pressure), 100h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-1.Catalyst weight consists of ZnBr₂Weight content is 27%, and ZnO weight content is 6%, and in catalyst, less than 450 DEG C total acid contents are 0.82mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 65.1% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 50%, and reaction temperature is 230 DEG C, and reaction pressure is 1MPa(absolute pressure), air speed is 500h^-1, it is passed through unstripped gas procatalyst and activates in a hydrogen atmosphere, reducing condition is 400 DEG C, 0.2MPa(absolute pressure), 1000h^-1, recovery time 4h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 63.82%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 2

Weigh 30g Hydrogen ZSM-5 molecular sieve (silica alumina ratio 100) carrier, be dipped in the NaOH aqueous solution that 450mL concentration is 1 mol/L, at 50 DEG C, stir 1h, then solid-liquid separation, 100 DEG C of dry 9h；Again dried sample is dipped in the aqueous hydrochloric acid solution that 900mL concentration is 1.5mol/L, at 50 DEG C, stirs 2h, then solid-liquid separation, 100 DEG C of dry 9h, 550 DEG C of roasting 6h.Weigh the sample after 20g roasting, join in the magnesium nitrate solution that 50mL concentration is 0.5mol/L, stand 12h, then at 120 DEG C of dry 12h, at 550 DEG C of roasting 6h, obtain the modified zsm-5 zeolite that content of magnesium is 3%.

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 120 DEG C of dry 4h, 500 DEG C of roasting 8h, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor with the mixed gas of nitrogen, bromomethane volumetric concentration is 80%, and treatment conditions are 250 DEG C, 0.3MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-2.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 30%, and ZnO weight content in terms of oxide is 4%, and in catalyst, less than 450 DEG C total acid contents are 0.89mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 67.3% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 70%, and reaction temperature is 230 DEG C, and reaction pressure is 2MPa(absolute pressure), air speed is 200h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 80%, and reducing condition is 450 DEG C, 0.3MPa(absolute pressure), 800h^-1, recovery time 4h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 63.28%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 3

Weighing 30g Hydrogen ZSM-5 molecular sieve (silica alumina ratio 150) carrier, being dipped in 300 mL concentration is the Na of 1.5mol/L₂CO₃In aqueous solution, at 80 DEG C, stir 0.5h, then solid-liquid separation, 80 DEG C of dry 12h；It is 2.5 that dried sample is dipped in 600mL concentration again In the aqueous sulfuric acid of mol/L, at 50 DEG C, stir 2h, then solid-liquid separation, 100 DEG C of dry 9h, 550 DEG C of roasting 6h.Weigh the sample after 20g roasting, join in the magnesium nitrate solution that 33mL concentration is 0.25mol/L, stand 12h, then at 120 DEG C of dry 12h, at 550 DEG C of roasting 6h, obtain the modified zsm-5 zeolite that content of magnesium is 1%.

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor with the mixed gas of nitrogen, bromomethane volumetric concentration is 30%, and treatment conditions are 300 DEG C, 0.1MPa(absolute pressure), 500h^-1, time 4h, prepare bromomethane preparing isobutene catalyst, be designated as C-3.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 33%, and ZnO weight content in terms of oxide is 2%, and in catalyst, less than 450 DEG C total acid contents are 0.93mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 70.2% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 80%, and reaction temperature is 200 DEG C, and reaction pressure is 3MPa(absolute pressure), air speed is 350h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 50%, and reducing condition is 500 DEG C, 0.1MPa(absolute pressure), 500h^-1, recovery time 4h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 48.32%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 4

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 500 DEG C of roasting 8h, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor, treatment conditions are 200 DEG C, 0.3MPa(absolute pressure), 300h^-1, time 1h, prepare bromomethane preparing isobutene catalyst, be designated as C-4.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 18%, and ZnO weight content in terms of oxide is 2%, and in catalyst, less than 450 DEG C total acid contents are 0.71mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 61.5% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 30%, and reaction temperature is 270 DEG C, and reaction pressure is 2MPa(absolute pressure), air speed is 350h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 70%, and reducing condition is 350 DEG C, 0.3MPa(absolute pressure), 800h^-1, recovery time 6h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 57.28%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 5

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 100 DEG C of dry 6h, 500 DEG C of lower roasting 6h of nitrogen protection, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor with the mixed gas of nitrogen, bromomethane volumetric concentration is 70%, and treatment conditions are 200 DEG C, 0.3MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-5.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 39%, and ZnO weight content in terms of oxide is 6%, and in catalyst, less than 450 DEG C total acid contents are 0.96mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 75.4% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane, and reaction temperature is 270 DEG C, and reaction pressure is 2MPa(absolute pressure), air speed is 350h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 60%, and reducing condition is 550 DEG C, 0.3MPa(absolute pressure), 800h^-1, recovery time 8h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 41.29%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 6

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, be dried 4h, roasting 4h under 500 DEG C of nitrogen atmospheres under 120 DEG C of nitrogen atmospheres, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor, treatment conditions are 250 DEG C, 0.2MPa(absolute pressure), 100h^-1, time 1h, it is designated as C-6.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 35%, and ZnO weight content in terms of oxide is 9%, and in catalyst, less than 450 DEG C total acid contents are 0.94mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 72.9% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 50%, and reaction temperature is 230 DEG C, and reaction pressure is 0.1MPa(absolute pressure), air speed is 500h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 80%, and reducing condition is 450 DEG C, 0.2MPa(absolute pressure), 1000h^-1, recovery time 4h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 59.83%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 7

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 120 DEG C of dry 4h, 500 DEG C of roasting 4h, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor with the mixed gas of nitrogen, bromomethane volumetric concentration is 90%, and treatment conditions are 300 DEG C, 0.1MPa(absolute pressure), 500h^-1, time 4h, prepare bromomethane preparing isobutene catalyst, be designated as C-7.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 20%, and ZnO weight content in terms of oxide is 1%, and in catalyst, less than 450 DEG C total acid contents are 0.74mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 63.6% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 80%, and reaction temperature is 200 DEG C, and reaction pressure is 3MPa(absolute pressure), air speed is 350h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 500 DEG C, 0.1MPa(absolute pressure), 500h^-1, recovery time 6h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 52.83%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Comparative example 1

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 120 DEG C of dry 4h, 500 DEG C of roasting 4h, prepare catalyst Z nO/Mg-ZSM-5, be designated as D-1.Obtain catalyst weight consisting of ZnO weight content in terms of oxide is 20%, and in catalyst, less than 450 DEG C total acid contents are 0.41mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 37.8% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 30%, and reaction temperature is 270 DEG C, and reaction pressure is 2MPa(absolute pressure), air speed is 350h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 70%, and reducing condition is 350 DEG C, 0.3MPa(absolute pressure), 800h^-1, recovery time 6h.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Comparative example 2

Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 120 DEG C of dry 4h, 500 DEG C of roasting 4h, prepare catalyst precarsor ZnO/Mg-ZSM-5.Being placed in continuous fixed bed reactor by 5g catalyst precarsor, use bromomethane to process catalyst precarsor with the mixed gas of nitrogen, bromomethane volumetric concentration is 80%, and treatment conditions are 250 DEG C, 0.3MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as D-2.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 30%, and ZnO weight content in terms of oxide is 4%, and in catalyst, less than 450 DEG C total acid contents are 0.89mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 65.7% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 70%, and reaction temperature is 230 DEG C, and reaction pressure is 2MPa(absolute pressure), air speed is 200h^-1.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Comparative example 3

Weighing appropriate zinc bromide to be dissolved in deionized water, use equi-volume impregnating to be carried on above-mentioned modified zsm-5 zeolite carrier, 80 DEG C of nitrogen atmospheres are dried 4h, 500 DEG C of nitrogen atmosphere roasting 4h, prepare catalyst Z nBr₂/ Mg-ZSM-5, is designated as D-3.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 30%, and in catalyst, less than 450 DEG C total acid contents are 0.97mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 75.3% of less than 450 DEG C total acid contents.

Bromomethane converts preparing isobutene reaction to be carried out in flowing micro fixed-bed reactor continuously.Catalyst loading amount 5g, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 70%, and reaction temperature is 230 DEG C, and reaction pressure is 2MPa(absolute pressure), air speed is 200h^-1.Before being passed through unstripped gas, catalyst activates under the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 80%, and reducing condition is 450 DEG C, 0.3MPa(absolute pressure), 800h^-1, recovery time 4h, reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 93.71%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Table 1 catalyst reaction performance

Claims

1. the preparation method of the catalyst with modified zsm-5 zeolite as carrier, it is characterised in that: include following process: Hydrogen ZSM-5 molecular sieve carrier is carried out aqueous slkali, acid solution and magnesium salt solution impregnation process by (1) respectively；(2) zinc oxide is introduced in the Hydrogen ZSM-5 molecular sieve carrier after processing；(3) the Hydrogen ZSM-5 molecular sieve carrier after introducing zinc oxide being carried out bromination process, in bromination to catalyst, zinc oxide weight content is 0.5%-20%, and zinc bromide weight content is 10%-50%.

Method the most according to claim 1, it is characterized in that: in step (1), impregnation process process is as follows: by Hydrogen ZSM-5 molecular sieve carrier, add in aqueous slkali by the liquid-solid ratio of 5mL/g-25mL/g, 0.5h-1.5h is stirred in room temperature to 80 DEG C, solid-liquid separation, gained solid is at 80 DEG C of-120 DEG C of dry 6h-12h；By dried sample, adding in acid solution by the liquid-solid ratio of 10mL/g-50mL/g, stir 1h-3h in 30 DEG C to 70 DEG C, solid-liquid separation, gained solid is at 80 DEG C of-120 DEG C of dry 6h-12h, then at 450 DEG C-650 DEG C roasting 4h-8h；Roasting sample is joined in magnesium salt solution, mixes in the ratio adding 1mL-5mL magnesium salt solution in every gram of ZSM-5 molecular sieve, stand 4h-12h, preferably 6h-10h, 80 DEG C of-120 DEG C of dry 6h-12h, then at 450 DEG C-650 DEG C roasting 4h-8h, obtain modified zsm-5 zeolite carrier.

Method the most according to claim 1, it is characterised in that: aqueous slkali is NaOH, KOH or Na₂CO₃One or more in aqueous solution, the concentration of aqueous slkali is 0.1mol/L-2mol/L；Acid solution is one or more in hydrochloric acid, nitric acid or sulfuric acid solution, and the concentration of acid solution is 0.1mol/L-5mol/L；In the modified zsm-5 zeolite carrier obtained, magnesium counts weight content in the carrier as 0.5%-10% with element.

Method the most according to claim 1, it is characterised in that: in step (2), zinc oxide is introduced to the method for modified hydrogen ZSM-5 molecular sieve carrier and uses impregnation method.

Method the most according to claim 4, it is characterised in that: use the Hydrogen ZSM-5 molecular sieve carrier that zinc solution dipping is modified, after drying, roasting, obtain bromomethane preparing isobutene catalyst precarsor.

Method the most according to claim 5, it is characterised in that: described drying condition is, temperature 60 C-150 DEG C, preferably 80 DEG C-120 DEG C；Time is 1h-24h, preferably 4h-8h；Described roasting condition is, temperature 200 DEG C-800 DEG C, preferably 400 DEG C-600 DEG C；Time is 1h-24h, preferably 4h-8h；Zinc salt is one or more in nitrate, hydrochlorate, acetate, citrate.

Method the most according to claim 1, it is characterised in that: in step (3), described bromination processes and refers to use gas phase bromine-containing compound to process the sample of load zinc oxide.

Method the most according to claim 7, it is characterised in that: bromine-containing compound refers to one or more in bromomethane, methylene bromide, bromoform.

Method the most according to claim 1, it is characterised in that: in step (3), using gas phase bromine-containing compound to carry out bromination process with the mixed gas of noble gas, bromomethane volumetric concentration is not less than 20%.

Method the most according to claim 1, it is characterized in that: concrete bromination process is as follows: the sample of load zinc oxide is placed in continuous fixed bed reactor, 150 DEG C-400 DEG C it are warming up under inert atmosphere, it is preferably 180 DEG C-350 DEG C, more preferably 200 DEG C-300 DEG C, being passed through gas phase bromine-containing compound gas, gas space velocity is 50h^-1-1000 h^-1, preferably 100h^-1-500h^-1；During process, system pressure is 0.1MPa-0.5MPa, preferably 0.1MPa-0.3MPa, and the process time is 0.5h-8h, preferably 1h-4h.

Catalyst prepared by 11. claim 1 to 10 either method, it is characterized in that: described catalyst is by zinc oxide, zinc bromide and modified zsm-5 zeolite carrier composition, based on the weight content of catalyst, zinc oxide content is 0.5%-20%, it is preferably 1%-15%, more preferably 1%-9%, zinc bromide content is 10%-50%, it is preferably 15%-45%, more preferably 18%-39%, modified zsm-5 zeolite vector contg is 40%-90%, it is preferably 50%-85%, more preferably 55%-80%, ZSM-5 molecular sieve carrier silica alumina ratio is 20 ~ 200, it is preferably 50 ~ 150.

12. catalyst according to claim 11, it is characterised in that: in catalyst, less than 450 DEG C total acid content (NH₃-TPD) it is 0.5mmol/g-1.3mmol/g, preferably 0.6mmol/g-1.2mmol/g, further preferred 0.7mmol-1.1mmol/g, the acid content of 250 DEG C-350 DEG C accounts for the 20%-90% of less than 450 DEG C total acid contents, preferably 30%-80%, further preferred 40%-80%.

Catalyst application in preparing isobutene described in 13. claim 11, it is characterized in that: include catalyst is carried out hydrogen reducing activation, making the content of halogen in catalyst is the 20%-90% of total halogen content in reduction procatalyst, then the catalyst after making halide activate with above-mentioned hydrogen reducing contacts, to prepare isobutene..

14. application according to claim 13, it is characterised in that: the condition of described hydrogen reducing activation makes the content of halogen in catalyst be preferably the 30%-80%, further preferred 40%-80% of total halogen content in reduction procatalyst.

15. application according to claim 13, it is characterised in that: the mode of described hydrogen reducing activation includes under an inert atmosphere by catalyzer temperature-elevating to 300 DEG C-600 DEG C；Then passing to air speed is 200h^-1-2000h^-1Hydrogen or the mixed gas of hydrogen and noble gas, keep 2h-16h at 0.1MPa-0.5MPa, in mixed gas, hydrogen volume percentage composition is 10%-95%.

16. application according to claim 15, it is characterised in that: it is warming up to 350 DEG C-550 DEG C；Then passing to air speed is 500h^-1-1000h^-1Hydrogen or the mixed gas of hydrogen and noble gas, keep 4h-8h at 0.1MPa-0.3MPa, in described mixed gas, hydrogen volume percentage composition is 30%-90%.

17. application according to claim 13, it is characterised in that: described halide is one or more in a halide, methylene halide, three halides.

18. application according to claim 13, it is characterised in that: the condition of described contact includes that reaction temperature is 150 DEG C-350 DEG C；Reaction pressure is 0.1MPa-5MPa；Air speed is 50h^-1-1000h^-1。

19. application according to claim 18, it is characterised in that: reaction temperature is 180 DEG C-300 DEG C more preferably 200-270 DEG C；Reaction pressure is 0.1MPa-3MPa；Air speed is 200h^-1-500h^-1。

20. application according to claim 13, it is characterised in that: include by catalyzer temperature-elevating to 300 DEG C-600 DEG C under inert atmosphere, preferably 350 DEG C-550 DEG C；Then passing to air speed is 200h^-1-2000h^-1, preferably 500h^-1-1000h^-1Hydrogen or the mixed gas of hydrogen and noble gas, at 0.1MPa-0.5MPa, it is preferably 0.1MPa-0.3MPa and processes 2h-16h, after being preferably 4h-8h, it is down to reaction temperature be passed through halide and react, in described gaseous mixture, hydrogen volume percentage composition is 10%-95%, preferably 30%-90%, more preferably 50%-90%.

21. application according to claim 13, it is characterised in that: raw material is the mixed gas of halide and noble gas, and in mixed gas, the volumetric concentration of halide is 10%-90%, preferably 30%-80%.

22. application according to claim 13, it is characterised in that: halide preparing isobutene reacts at fixed bed, fluid bed, fixed fluidized bed, moving bed, carries out in slurry bed system or fluidized bed reactor.