CN106140228A

CN106140228A - Bromomethane preparing isobutene catalyst prepared by a kind of cocrystallization and its preparation method and application

Info

Publication number: CN106140228A
Application number: CN201510135854.5A
Authority: CN
Inventors: 张舒冬; 张信伟; 孙晓丹; 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: CN106140228B

Abstract

The present invention discloses bromomethane preparing isobutene catalyst prepared by a kind of cocrystallization and its preparation method and application.The preparation method of catalyst, including following process: (1) preparation is containing polyhydric alcohol, zinc salt and the aqueous solution of aluminium salt；(2) by being evaporated under the mixed solution reduced pressure of step (1), obtain solid crystal, then grind；(3) in oxygen and calcination steps (2) gained solid under noble gas mixed atmosphere, the then molding of flowing continuously；(4) step (3) gained sample being carried out bromination process, in the catalyst after bromination, zinc oxide weight content is 0.5%-20%, and zinc bromide weight content is 10%-50%.This catalyst can significantly improve the selectivity of isobutene. for the reaction of bromomethane preparing isobutene.

Description

Bromomethane preparing isobutene catalyst prepared by a kind of cocrystallization and its preparation method and application

Technical field

The present invention relates to a kind of bromomethane preparing isobutene catalyst and its preparation method and application, relate in particular to a kind of cocrystallization and prepare methane height selectivity preparing isobutene catalyst and methods and applications 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.

Can the many chemical products of preparation 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, Jieli He, the Ting Xu, Zhihui such as Wang Ye 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 bromo-hydrocarbons is converted into dimethyl ether, methanol and metal bromide on metal oxide catalyst, 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 invention provides and a kind of prepare bromomethane height with cocrystallization method and selectively produce isobutene catalyst and its preparation method and application.

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

(1) preparation is containing polyhydric alcohol, zinc salt and the aqueous solution of aluminium salt；

(2) by being evaporated under the mixed solution reduced pressure of step (1), obtain solid crystal, then grind；

(3) in oxygen and calcination steps (2) gained solid under noble gas mixed atmosphere, the then molding of flowing continuously；

(4) step (3) gained sample being carried out bromination process, in the catalyst after bromination, zinc oxide weight content is 0.5%-20%, and zinc bromide weight content is 10%-50%.

Polyhydric alcohol described in the preparation method step (1) of above-mentioned bromomethane preparing isobutene catalyst is selected from the carbon number alcohols between 4-7 and containing more than three hydroxyls, preferably xylitol, glucose；Described zinc salt and aluminium salt one in nitrate, hydrochlorate, sulfate, acetate, preferably nitrate；In the described aqueous solution containing polyhydric alcohol, zinc salt and aluminium salt, polyol agent amount is 0.5-4 times of zinc and aluminum material amount summation, preferably 1-3 times, and in solution, polyhydric alcohol molar concentration is 1mol/L-5mol/L, preferably 2mol/L-4mol/L.

Described in the preparation method step (2) of above-mentioned bromomethane preparing isobutene catalyst, mixed solution is evaporated temperature is 40 DEG C-80 DEG C, preferably 50 DEG C-70 DEG C.

Oxygen described in the preparation method step (3) of above-mentioned bromomethane preparing isobutene catalyst is 1%-10%, preferably 2%-6% with carrier of oxygen volume concentrations in the mixing edema caused by disorder of QI of noble gas；Sintering temperature is 400 DEG C-800 DEG C, preferably 500 DEG C-700 DEG C；Roasting time is 4h-72h, preferably 12h-36h；Gaseous mixture air speed is 500h^-1-5000h^-1, preferably 1000^-1-3000^-1.Described molding is carried out by this area general technology method, such as methods such as extrusion, tabletting, spin, can make or choose suitable particle shape according to the needs used, as made bar shaped, sheet shape, cylindricality, spherical etc..

Bromination described in the preparation method step (4) of above-mentioned bromomethane preparing isobutene catalyst 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.

Noble gas involved in the preparation method step (4) of above-mentioned bromomethane preparing isobutene catalyst 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 bromomethane preparing isobutene catalyst, is made up of zinc oxide, zinc bromide and aluminium sesquioxide, and zinc oxide weight content is 0.5%-20%, preferably 1%-15%, further preferred 1%-9%；Zinc bromide weight content is 10%-50%, preferably 15%-45%, further preferred 18%-39%；Aluminium sesquioxide weight content 40%-90%, preferably 50%-85%, further preferred 55%-80%.

In above-mentioned bromomethane preparing isobutene catalyst, less than 450 DEG C total acid contents (NH3-TPD) are 0.5mmol/g-1.3mmol/g, preferably 0.6mmol/g-1.2mmol/g, further preferably 0.7mmol/g-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%, more preferably 50%-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^-1The 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 method that the present invention relates to.Catalyst prepared by the cocrystallization method that the present invention relates to utilizes zinc salt different from aluminium salt degree of crystallinity, make Zn Yu Al fractional crystallization out, utilize gluing effect two kinds of crystal of dispersion of polyhydric alcohol, it is ensured that there is between Zn and Al weak interaction, be uniformly dispersed simultaneously simultaneously.Carry out bromomethane by the inventive method and convert preparing isobutene reaction, bromomethane conversion ratio more than 90%, selective isobutene more than 80%.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 used is MICROMERITICS company of U.S. AutoChem 2920 chemical adsorption instrument, concrete to measure process as follows: sample is cooled to 150 DEG C by helium purge after 1 hour at 450 DEG C, introduce 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

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-1.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 0.94mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 78.37% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 61.77%.

After activation terminates, being down to reaction temperature, be passed through unstripped gas, 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 350h^-1.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 2

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 2mol/L, and aluminum nitrate and zinc nitrate total concentration are 2 mol/L.Mixed solution is heated to 70 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 6%, sintering temperature 500 DEG C, roasting time 12h, gaseous mixture air speed 1000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(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 0.81mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 69.35% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 69.57%.

Embodiment 3

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 2mol/L, and aluminum nitrate and zinc nitrate total concentration are 1mol/L.Mixed solution is heated to 50 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 2%, sintering temperature 700 DEG C, roasting time 24h, gaseous mixture air speed 3000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(absolute pressure), 300h^-1, time 2h, 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 1.02mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 66.27% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 52.18%.

Embodiment 4

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 4mol/L, and aluminum nitrate and zinc nitrate total concentration are 2 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-4.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 0.93mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 74.86% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 90%, and activation condition is 400 DEG C, 0.1MPa(absolute pressure), 1000h^-1, soak time 8h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 63.45%.

After activation terminates, being down to reaction temperature, be passed through unstripped gas, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 40%, 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.

Embodiment 5

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1 mol/L.Mixed solution is heated to 50 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 2%, sintering temperature 500 DEG C, roasting time 36h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(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 30%, and ZnO weight content in terms of oxide is 4%, and in catalyst, less than 450 DEG C total acid contents are 1.07mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 61.1% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 50%, and activation condition is 350 DEG C, 0.3MPa(absolute pressure), 500h^-1, soak time 4h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 73.45%.

After activation terminates, being down to reaction temperature, be passed through unstripped gas, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 80%, and reaction temperature is 250 DEG C, and reaction pressure is 0.1MPa(absolute pressure), air speed is 200h^-1.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 6

Preparation glucose, aluminum nitrate, zinc nitrate aqueous solution, wherein concentration of glucose is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(absolute pressure), 300h^-1, time 2h, 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 0.92mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 77.21% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 500 DEG C, 0.2MPa(absolute pressure), 1000h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 58.24%.

After activation terminates, being down to reaction temperature, be passed through unstripped gas, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 70%, and reaction temperature is 210 DEG C, and reaction pressure is 02MPa(absolute pressure), air speed is 500h^-1.After stable reaction one hour, sampling analysis.Reaction result is shown in Table 1.

Embodiment 7

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.3MPa(absolute pressure), 100h^-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 0.92mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 77.54% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 60.21%.

After activation terminates, being down to reaction temperature, be passed through unstripped gas, unstripped gas is bromomethane and nitrogen mixed gas, and wherein bromomethane volume content is 60%, and reaction temperature is 230 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.

Embodiment 8

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by catalyst precarsor, use methyl bromide gas to process catalyst precarsor, treatment conditions are 200 DEG C, 0.1MPa(absolute pressure), 500h^-1, time 1h, prepare bromomethane preparing isobutene catalyst, be designated as C-8.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 0.95mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 76.81% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 62.99%.

Embodiment 9

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-1.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 1.03mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 75.44% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 65.53%.

Embodiment 10

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst precarsor ZnO/Al₂O₃.Being placed in continuous fixed bed reactor by 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, 0.2MPa(absolute pressure), 300h^-1, time 2h, prepare bromomethane preparing isobutene catalyst, be designated as C-1.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 0.89mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 79.27% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h；Reduction rear catalyst in content of halogen be reduction procatalyst in total halogen content 60.89%.

Comparative example 1

Prepare catalyst by embodiment 1, preparation process does not use bromination process.Detailed process is as follows:

Preparation xylitol, aluminum nitrate, zinc nitrate aqueous solution, wherein xylitol concentration is 3mol/L, and aluminum nitrate and zinc nitrate total concentration are 1.5 mol/L.Mixed solution is heated to 60 DEG C, is evaporated under a reduced pressure, obtain solid crystal thing, pulverize.After pulverizing solid oxygen, nitrogen mixed atmosphere under roasting, carrier of oxygen volume concentrations is 4%, sintering temperature 600 DEG C, roasting time 24h, gaseous mixture air speed 2000h^-1, prepare catalyst 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 0.29mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 54.7% 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, catalyst uses the gaseous mixture activation of hydrogen and nitrogen before use, and in mixed gas, hydrogen volume content is 70%, and activation condition is 450 DEG C, 0.2MPa(absolute pressure), 750h^-1, soak time 6h.

Comparative example 2

Take catalyst C-1 the most activated, directly carry out bromomethane conversion reaction.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 350h^-1.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 a bromomethane preparing isobutene catalyst, it is characterised in that: include following process:

Method the most according to claim 1, it is characterised in that: polyhydric alcohol described in step (1) is selected from the carbon number alcohols between 4-7 and containing more than three hydroxyls；Described zinc salt and aluminium salt one in nitrate, hydrochlorate, sulfate, acetate；In the described aqueous solution containing polyhydric alcohol, zinc salt and aluminium salt, the amount of polyol agent is 0.5-4 times of the zinc amount summation with aluminum material；In solution, polyhydric alcohol molar concentration is 1mol/L-5mol/L.

Method the most according to claim 2, it is characterised in that: in step (1), polyhydric alcohol is xylitol, glucose；Described zinc salt and aluminium salt are nitrate；In the described aqueous solution containing polyhydric alcohol, zinc salt and aluminium salt, the amount of polyol agent is 1-3 times of the zinc amount summation with aluminum material, and in solution, polyhydric alcohol molar concentration is 2mol/L-4mol/L.

Method the most according to claim 1, it is characterised in that: it is 40 DEG C-80 DEG C that mixed solution described in step (2) is evaporated temperature.

Method the most according to claim 1, it is characterised in that: oxygen described in step (3) is 1%-10% with carrier of oxygen volume concentrations in the mixing edema caused by disorder of QI of noble gas；Sintering temperature is 400 DEG C-800 DEG C, and roasting time is 4h-72h；Gaseous mixture air speed is 500h^-1-5000h^-1。

Method the most according to claim 1, it is characterised in that: bromination described in step (4) processes and refers to use gas phase bromine-containing compound to process the sample of load zinc oxide.

Method the most according to claim 6, it is characterised in that: bromine-containing compound refers to one or more in bromomethane, methylene bromide, bromoform.

Method the most according to claim 6, 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%.

Method the most according to claim 6, 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.

Method the most according to claim 9, it is characterised in that: noble gas is nitrogen, argon or helium.

Catalyst prepared by 11. claim 1 to 10 either method, it is characterised in that: catalyst is made up of zinc oxide, zinc bromide and aluminium sesquioxide, and zinc oxide weight content is 0.5%-20%；Zinc bromide weight content is 10%-50%；Aluminium sesquioxide weight content 40%-90%.

12. catalyst according to claim 11, it is characterised in that: zinc oxide weight content is 1%-15%；Zinc bromide weight content is 15%-45%；Aluminium sesquioxide weight content is 50%-85%.

13. catalyst according to claim 13, it is characterised in that: zinc oxide weight content is 1%-9%；Zinc bromide weight content is 18%-39%；Aluminium sesquioxide weight content is 55%-80%.

14. catalyst according to claim 11, it is characterised in that: in catalyst, less than 450 DEG C total acid contents are 0.5mmol/g-1.3mmol/g, and the acid content of 250 DEG C-350 DEG C accounts for the 20%-90% of less than 450 DEG C total acid contents.

Catalyst application in preparing isobutene described in 15. 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..

16. application according to claim 15, 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.

17. application according to claim 15, 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%.

18. application according to claim 17, 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%.

19. application according to claim 15, it is characterised in that: described halide is one or more in a halide, methylene halide, three halides.

20. application according to claim 19, it is characterised in that: described halide is one or more in bromomethane, methylene bromide, bromoform.

21. application according to claim 15, 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。

22. application according to claim 22, it is characterised in that: reaction temperature is 180 DEG C-300 DEG C；Reaction pressure is 0.1MPa-3MPa；Air speed is 200h^-1-500h^-1。

23. application according to claim 15, it is characterised in that: include catalyzer temperature-elevating to 300 DEG C-600 DEG C under inert atmosphere；Then passing to air speed is 200h^-1-2000h^-1The mixed gas of hydrogen and noble gas, after 0.1MPa-0.5MPa processes 2h-16h, be down to reaction temperature and be passed through halide and react.

24. application according to claim 15, 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.