CN106140274A

CN106140274A - A kind of catalyst of bromomethane height selectivity preparing isobutene and preparation method thereof

Info

Publication number: CN106140274A
Application number: CN201510135841.8A
Authority: CN
Inventors: 孙晓丹; 张舒冬; 张信伟; 李�杰; 倪向前; 张喜文; 刘继华
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: CN106140274B

Abstract

The present invention discloses catalyst of a kind of bromomethane height selectivity preparing isobutene and preparation method thereof.Preparation method includes following process: (1), by soluble in water to ammonium molybdate and ammonium tungstate, obtains solution A；(2) carrier is joined in the solution A that step (1) obtains, after aging, dry, calcination process, obtain catalyst precarsor B；(3) the catalyst precarsor B using reducing atmosphere to obtain step (2) carries out reduction treatment；(4) the catalyst precarsor B after reduction step (3) obtained and polyhydric alcohol solutions join in autoclave, react 2～5h at 200～300 DEG C；(5) reaction effluent step (4) obtained filters, and is dried to obtain catalyst precarsor C；(6) zinc oxide is introduced to catalyst precarsor C, obtains catalyst precarsor D.(7) catalyst precarsor D being carried out bromination process, obtaining zinc oxide weight content is 0.5%-20%, and zinc bromide weight content is the bromomethane preparing isobutene catalyst of 10%-50%.Catalyst prepared by the method can improve the selectivity of isobutene..

Description

A kind of catalyst of bromomethane height selectivity preparing isobutene and preparation method thereof

Technical field

The present invention relates to catalyst of a kind of bromomethane height selectivity preparing isobutene and preparation method thereof.

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 catalyst of a kind of bromomethane height selectivity preparing isobutene and preparation method thereof.

A kind of preparation method of the catalyst of bromomethane height selectivity preparing isobutene, including following process:

(1) by soluble in water to ammonium molybdate and ammonium tungstate, solution A is obtained；

(2) carrier is joined in the solution A that step (1) obtains, after aging, dry, calcination process, obtain catalyst precarsor B；In described catalyst precarsor B, molybdenum counts content in the carrier as 1wt%～8wt% with element, preferably 3wt%～6wt%, tungsten counts content in the carrier as 1wt%～3wt% with element, described carrier includes one or more in aluminium oxide, silicon oxide, Hydrogen ZSM-5 molecular sieve, preferably Hydrogen ZSM-5 molecular sieve carrier, further preferred Hydrogen ZSM-5 molecular sieve carrier silica alumina ratio is 20 ~ 200, preferably 20 ~ 150；

(3) the catalyst precarsor B using reducing atmosphere to obtain step (2) carries out reduction treatment；

(4) the catalyst precarsor B after reduction step (3) obtained and polyhydric alcohol solutions join in autoclave, and with hydrogen exchange 2～5 times after sealing, then regulation Hydrogen Vapor Pressure is to 2～4MPa, reacts 2～5h at 200～300 DEG C；

(5) reaction effluent step (4) obtained places 1～3h, then filters, and gained solid sample is at room temperature dried, until sample surfaces is without liquid phase, obtains catalyst precarsor C；

(6) zinc oxide is introduced to catalyst precarsor C, obtains catalyst precarsor D.

(7) catalyst precarsor D being carried out bromination process, obtaining zinc oxide weight content is 0.5%-20%, and zinc bromide weight content is the bromomethane preparing isobutene catalyst of 10%-50%.

In above-mentioned preparation method step (1), in described solution A, the concentration of molybdenum is 0.05～1mol/L, and the concentration of tungsten is 0.01～0.3mol/L.

In above-mentioned preparation method step (2), described aging can be the most aging, it is also possible to the most aging, aging temperature is 10～90 DEG C, preferably 20～60 DEG C, and ageing time is 1～24h, preferably 4～12h.Described baking temperature is 70～150 DEG C, preferably 80～120 DEG C, and drying time is 2～12h, preferably 4～8h.Described sintering temperature is 350～650 DEG C, preferably 400～600 DEG C, and roasting time is 2～12h, preferably 4～8h.

In above-mentioned preparation method step (3), described reducing atmosphere is the mixed gas of hydrogen or hydrogen and nitrogen, and in described gaseous mixture, hydrogen volume percentage composition is 10%～95%..Concrete reduction treatment process is as follows: under nitrogen atmosphere, catalyst precarsor is warming up to 300～600 DEG C, then passes to the mixed gas of hydrogen or hydrogen and nitrogen, in 0.1～0.5MPa(absolute pressure) process 4～8h after, be down to room temperature in a nitrogen atmosphere.

In above-mentioned preparation method step (4), described polyhydric alcohol can be one or more in xylitol, sorbitol, mannitol, arabitol；The mass concentration of polyhydric alcohol solutions is 5%～10%；The volume ratio of the reduction rear catalyst precursor B that polyhydric alcohol solutions and step (3) obtain is 5～10.

In above-mentioned preparation method step (6), described zinc oxide is introduced to the method that the method for catalyst precarsor C is well known to those skilled in the art, as impregnation method can be used to introduce.Concrete grammar is as follows: uses zinc solution impregnated catalyst precursor C, obtains catalyst precarsor E 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 (7), 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 (7), 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 of bromomethane height selectivity preparing isobutene, based on the weight content of catalyst, zinc oxide content is 0.5%-20%, preferably 1%-15%, more preferably 1%-9%, zinc bromide content is 10%-50%, being preferably 15%-45%, more preferably 18%-39%, vector contg is 40%-90%, it is preferably 50%-85%, more preferably 55%-80%.

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 catalyst, 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, and the catalyst after then 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 ratio85%Above, selective isobutene50%Above.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 appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；(pore volume is 0.71ml/g, and specific surface area is 236m to use equi-volume impregnating to be carried on aluminium oxide²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 4h, 80 DEG C of dry 12h, 500 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in 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), recovery time 4h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 3 times after sealing, then regulation Hydrogen Vapor Pressure is to 3MPa, reacts 4h at 220 DEG C；Reacted mixture in above-mentioned autoclave being placed 2h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 80 DEG C of dry 8h, 600 DEG C of roasting 4h, prepare catalyst precarsor D₃.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D, 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 30%, and ZnO weight content is 4%, and in catalyst, less than 450 DEG C total acid contents are 0.75mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 48.1% 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 71.31%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 2

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；(pore volume is 1.06ml/g, and specific surface area is 387m to use equi-volume impregnating to be carried on silicon oxide²/ g, spherical, equivalent diameter 0.5mm) carrier, aged at room temperature 8h, 120 DEG C of dry 6h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 10%, and reducing condition is 500 DEG C, 0.2MPa(absolute pressure), recovery time 6h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 2 times after sealing, then regulation Hydrogen Vapor Pressure is to 3MPa, reacts 4h at 220 DEG C；Reacted mixture in above-mentioned autoclave being placed 3h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 120 DEG C of dry 4h, 500 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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 0.78mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 59.2% 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 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 58.12%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 3

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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 30%, and ZnO weight content in terms of oxide is 4%, and in catalyst, less than 450 DEG C total acid contents are 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.7% 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 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 51.37%.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 4

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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-4.Obtain catalyst weight and consist of ZnBr₂In terms of bromide, weight content is 27%, and ZnO weight content in terms of oxide is 6%, and in catalyst, less than 450 DEG C total acid contents are 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.7% of less than 450 DEG C total acid contents.

Embodiment 5

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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-5.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 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.7% of less than 450 DEG C total acid contents.

Embodiment 6

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the arabitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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-6.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 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.7% of less than 450 DEG C total acid contents.

Embodiment 7

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 5%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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-7.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 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.7% of less than 450 DEG C total acid contents.

Comparative example 1

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst, 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 0.38mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 35.5% 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 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.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Comparative example 2

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weigh appropriate zinc nitrate to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 100 DEG C of vacuum drying 8h, 400 DEG C of roasting 8h, prepare catalyst precarsor D.Being placed in continuous fixed bed reactor by 5g catalyst precarsor D, use bromomethane to process catalyst precarsor D 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 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 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.7% 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 80%, and reaction temperature is 200 DEG C, and reaction pressure is 3MPa(absolute pressure), air speed is 350h^-1.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Comparative example 3

Weigh appropriate ammonium molybdate and appropriate ammonium tungstate is dissolved in deionized water, obtain solution A；Using equi-volume impregnating to be carried on Hydrogen ZSM-5(silica alumina ratio 50, pore volume is 0.23ml/g, and specific surface area is 426m²/ g, bar shaped, equivalent diameter 1.5mm) carrier, aged at room temperature 6h, 110 DEG C of dry 10h, 600 DEG C of roasting 4h, prepare catalyst precarsor B, wherein Mo accounts for vehicle weight 5% in terms of element, and W accounts for vehicle weight 2% in terms of element；Catalyst precarsor B activates in the mixed atmosphere of hydrogen, and in mixed gas, hydrogen volume content is 90%, and reducing condition is 400 DEG C, 0.2MPa(absolute pressure), recovery time 8h；Joining in autoclave by the catalyst precarsor B after reduction activation with the sorbitol solution that 300mL mass concentration is 10%, use hydrogen exchange 4 times after sealing, then regulation Hydrogen Vapor Pressure is to 2MPa, reacts 2h at 300 DEG C；Reacted mixture in above-mentioned autoclave being placed 1h, filters, gained solid sample is dried at room temperature for sample surfaces without liquid phase, obtains catalyst precarsor C；Weighing appropriate zinc bromide to be dissolved in deionized water, use equi-volume impregnating to be carried on catalyst precarsor C, 80 DEG C of nitrogen atmospheres are dried 4h, 500 DEG C of nitrogen atmosphere roasting 4h, prepare catalyst, are 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 0.95mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 70.3% of less than 450 DEG C total acid contents.

Table 1 catalyst reaction performance

Claims

1. the preparation method of the catalyst of a bromomethane height selectivity preparing isobutene, it is characterised in that: include following process:

(2) carrier is joined in the solution A that step (1) obtains, after aging, dry, calcination process, obtain catalyst precarsor B；In described catalyst precarsor B, molybdenum counts content in the carrier as 1wt%～8wt% with element, and tungsten counts content in the carrier as 1wt%～3wt% with element, and described carrier includes one or more in aluminium oxide, silicon oxide, Hydrogen ZSM-5 molecular sieve；

(6) zinc oxide is introduced to catalyst precarsor C, obtains catalyst precarsor D；

Method the most according to claim 1, it is characterised in that: in step (1) solution A, the concentration of molybdenum is 0.05～1mol/L, and the concentration of tungsten is 0.01～0.3mol/L.

Method the most according to claim 1, it is characterised in that: in step (2), aging temperature is 10～90 DEG C, and ageing time is 1～24h, described baking temperature is 70～150 DEG C, and drying time is 2～12h, sintering temperature is 350～650 DEG C, and roasting time is 2～12h.

Method the most according to claim 1, it is characterised in that: in step (2), carrier is Hydrogen ZSM-5 molecular sieve carrier, and the silica alumina ratio of molecular sieve is 20 ~ 200.

Method the most according to claim 1, it is characterised in that: the reducing atmosphere described in step (3) is the mixed gas of hydrogen or hydrogen and nitrogen, and in described gaseous mixture, hydrogen volume percentage composition is 10%～95%.

Method the most according to claim 5, it is characterized in that: concrete reduction treatment process is as follows: under nitrogen atmosphere, catalyst precarsor is warming up to 300～600 DEG C, then pass to the mixed gas of hydrogen or hydrogen and nitrogen, after processing 4～8h 0.1～0.5MPa, it is down to room temperature in a nitrogen atmosphere.

Method the most according to claim 1, it is characterised in that: the polyhydric alcohol described in step (4) can be one or more in xylitol, sorbitol, mannitol, arabitol；The mass concentration of polyhydric alcohol solutions is 5%～10%；The volume ratio of the reduction rear catalyst precursor B that polyhydric alcohol solutions and step (3) obtain is 5～10.

Method the most according to claim 1, it is characterised in that: in step (6), zinc oxide is introduced to catalyst precarsor C and uses impregnation method introducing.

Method the most according to claim 8, it is characterised in that: use zinc solution impregnated catalyst precursor C, after drying, roasting, obtain catalyst precarsor E, baking temperature is 60 DEG C-150 DEG C, time is 1h-24h, sintering temperature 200 DEG C-800 DEG C, and the time is 1h-24h.

Method the most according to claim 8, it is characterised in that: zinc salt is one or more in nitrate, hydrochlorate, acetate, citrate.

11. methods according to claim 1, it is characterised in that: bromination described in step (7) processes and refers to use gas phase bromine-containing compound to process the sample of load zinc oxide.

12. methods according to claim 11, it is characterised in that: bromine-containing compound refers to one or more in bromomethane, methylene bromide, bromoform.

13. methods according to claim 11, it is characterised in that: 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%.

14. methods according to claim 11, it is characterized in that: concrete bromination process is as follows: the sample of load zinc oxide is placed in continuous fixed bed reactor, being warming up to 150 DEG C-400 DEG C under inert atmosphere, be passed through gas phase bromine-containing compound gas, gas space velocity is 50h^-1-1000 h^-1；System pressure is 0.1MPa-0.5MPa, and the process time is 0.5h-8h.

15. methods according to claim 11, it is characterised in that: being warming up to 180 DEG C-350 DEG C under inert atmosphere, be passed through gas phase bromine-containing compound gas, gas space velocity is 100h^-1-500h^-1；System pressure is 0.1MPa-0.3MPa, and the process time is 1h-4h.

16. one kind uses catalyst prepared by claim 1 to 15 either method, it is characterized in that: based on the weight content of catalyst, zinc oxide content is 0.5%-20%, preferably 1%-15%, more preferably 1%-9%, zinc bromide content is 10%-50%, being preferably 15%-45%, more preferably 18%-39%, vector contg is 40%-90%, it is preferably 50%-85%, more preferably 55%-80%.

17. catalyst according to claim 16, it is characterized in that: less than 450 DEG C total acid contents are 0.5mmol/g-1.3mmol/g, preferably 0.6mmol/g-1.2mmol/g, further preferably 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 18. claim 16, 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..

19. application according to claim 18, it is characterised in that: the condition of described hydrogen reducing activation makes the content of halogen in catalyst be preferably the 30%-80% of total halogen content in reduction procatalyst.

20. application according to claim 18, 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%；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%.

21. application according to claim 18, it is characterised in that: described halide is one or more in one or more in a halide, methylene halide, three halides, preferably bromomethane, methylene bromide, bromoform.

22. application according to claim 18, 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；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。

23. application according to claim 18, 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, in 0.1MPa-0.5MPa(absolute pressure), it is preferably 0.1MPa-0.3MPa(absolute pressure) process 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%.

24. application according to claim 18, 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%.

25. application according to claim 18, it is characterised in that: the reaction of halide preparing isobutene is carried out in fixed bed, fluid bed, fixed fluidized bed, moving bed, slurry bed system or fluidized bed reactor.