CN105712829B - The method that MTBE and TBA compounds prepare isobutene - Google Patents

Abstract

The invention discloses a kind of method that MTBE and TBA compounds prepare isobutene.This method uses fixed-bed process, carried out in the reactor of at least two series connection, previous reactor is using TBA as raw material, dehydration is carried out in the presence of TBA dehydration catalysts, product after dehydration enters the latter reactor with MTBE and TBA compounds, reacted in the presence of following catalyst, prepare isobutene；Catalyst contains core shell structure component used by wherein latter reactor, and core is amorphous silica-alumina, and shell is the aluminum oxide by silicon and tin modification.This method can realize MTBE cracking and TBA is dehydrated two kinds of reactions while carries out generation isobutene, make TBA conversion ratio and MTBE conversion ratio it is higher, and the addition of water when MTBE is cracked is avoided or reduces, energy consumption of reaction is reduced, the selectivity for generating isobutene is also higher.

Description

The method that MTBE and TBA compounds prepare isobutene

Technical field

The present invention relates to a kind of method that isobutene is prepared by cracking, especially suitable for MTBE（Methyl tertiary butyl ether(MTBE)）With TBA（The tert-butyl alcohol）Compound prepares isobutene.

Background technology

Isobutene is important Organic Chemicals, using its as raw material mainly for the production of methyl methacrylate (MMA), Butyl rubber, polyisobutene, tertiary butyl phenol, tert-butylamine, methylallyl chloride, trimethylace tonitric, isoprene, p-tert-octyl phenol, The fine chemical products such as antioxidant, agriculture medicine intermediate, tert-butyl acetate, silane.The raw material of production isobutene is mainly derived from The by-product C-4-fraction of naphtha steam cracking ethylene unit, refinery fluid catalytic cracking（FCC）The by-product carbon four of device By-product tert-butyl alcohol etc. in cut and the synthesis of Halcon methods expoxy propane, wherein industrial process mainly have sulfuric acid extraction, Adsorption method of separation, tert-butyl alcohol dehydration method, methyl tertiary butyl ether(MTBE) cracking and n-butene isomerization process etc..

MTBE cracking is many to prepare advanced technology in isobutene method, a kind of method of better economy.Split in MTBE Solve in preparing isobutene course of reaction, main reaction is under the effect of catalyst, and MTBE is cracked into isobutene and methanol, most passes through afterwards The processes such as rectifying obtain isobutene or high-purity isobutene.The catalyst type of MTBE cracking preparing isobutenes is more, including aluminum oxide, Silica, amorphous silica-alumina, ion exchange resin, molecular sieve, solid phosphoric acid and other acidic resin catalyst systems.Such as MTBE disclosed in CN1853772A, CN102451674A, JP2004115407, JP2004091443, JP3220136 etc. is cracked Preparing isobutene catalyst is amorphous silicon aluminum-based catalyst, for another example patent DE 3509292, DE 3210435, US 4447668th, GB 1482883, US 4570026, US 4551567 etc. then use ion-exchange resin catalyst catalyst, and again Such as patent CN 96123535.7, EP 0118085, JP 7626401, JP 7494602 are with solid phosphoric acid, sulfate, activity Charcoal is as MTBE catalyst for cracking.When MTBE is cracked, water filling simultaneously is needed mostly, to prevent from generating Diisobutylene, dimethyl ether Deng accessory substance.

Another the more universal method for producing isobutene is TBA dehydrations.The reaction of TBA dehydration preparing isobutenes has The features such as accessory substance is few, separation and purification is easy, reduced investment.Conventional catalyst includes aluminum oxide, molecular sieve, azochlorosulfonate acid ion and exchanged Resin etc..The isobutene dehydration catalyst as disclosed in US3665048, CN101300211A, CN102516030A etc. is oxidation Aluminum-based catalyst.For another example it is using sulfonate resin as catalyst in US4423271, US2005/0014985A1 etc.. The catalyst for tert-butyl alcohol cracking reaction that CN103611572A and CN103506158A is provided, is prepared into by following methods Arrive:Melt pelletization method is first passed through by polystyrene, chliorinated polyvinyl chloride, polytrifluorochloroethylene and Kynoar or poly- tribromo It is granulated after styrene blending, melting, it is then granulated to obtain described catalyst with sulfur trioxide progress sulfonating reaction.

In production process, MTBE and TBA compounds are more often met.Its main source has two kinds.The first source is with different Butylene can produce the TBA of more amount initial stages with the driving that methanol is waste MTBE.Because when going into operation, catalyst Or（And）A certain amount of water may be adulterated in installing pipes, excessive isobutene is readily generated TBA with water reaction.To industry For device, also imply that and considerable amount of MTBE and TBA product mix generation is had at the initial stage of going into operation.MTBE and TBA mixing productions Product are separated as waste disposal, or using MTBE/TBA knockout towers, respectively obtain target product MTBE and TBA.

Second of source, and most important source are artificially to produce, i.e., coproduction TBA while MTBE is prepared.First, It is that the special technology for producing TBA has some problems.TBA production technologies are complex, due to the intersolubility of C-4-fraction and water It is poor, therefore TBA product designs only have 45%-55%, TBA azeotrope with water is difficult separation in addition, and conventional distillation can only obtain 85% TBA.The TBA products of higher concentration can just be obtained by being typically employed to multitple extraction rectifying, but equipment investment and operating cost will be big Amplitude improves.Secondly, coproduction TBA has technical advantage while preparing MTBE:（1）Scheme simple and flexible.Can be according to production The demand of product commercially is suitably adjusted to process program.Only technological process need to simply be switched and be changed suitably Catalyst, so that it may realize per unit area yield MTBE or TBA, and MTBE and TBA mixtures.（2）Flow is convenient to carry out, and investment risk is small. It is convenient to carry out by being transformed per unit area yield MTBE techniques with regard to that can be easy to switch to joint production process.Simultaneously again can be easily extensive Traditional per unit area yield technique is arrived again, and MTBE/TBA knockout towers more than needed can be used for carrying out the separation of n-butene in C-4-fraction.Cause This, investment risk is not present in the technology.Finally, combined production device investment cost is low.If there is special per unit area yield MTBE and special in manufacturer Per unit area yield TBA devices, the two each architectonical, mutual equipment can not borrow, therefore more than the equipment of joint production process, investment Greatly.Combined production device can produce MTBE and TBA simultaneously, produce MTBE respectively with scale set than newly-built two sets and TBA reduces investment outlay More than 40%, while also significantly reduce operating cost.Therefore, coproduction TBA technologies have obtained extensively while MTBE is prepared General attention.The Lu Chunlong of Xi'an Petroleum University in its Master's thesis, " analyze and be related to just with TBA coproduction by the optimization of MTBE devices Visit " in, just prepare MTBE while coproduction TBA technologies carried out serious analysis, obtained affirm answer. CN200610104876.6 discloses a kind of isobutene with C-4-fraction and methanol-water coproducing methyl tertbutyl ether and tertiary fourth The production method of alcohol.But MTBE the and TBA compound products of coproduction, main whereabouts are divided using MTBE/TBA knockout towers From respectively obtaining target product MTBE and TBA.

Whether MTBE the and TBA compounds that the first source or second of source obtain, at this stage, compound is used When producing isobutene, substantially then distinguished using purer MTBE raw materials and TBA raw materials is obtained after compound is separated Distinguish preparing isobutene on MTBE crackers and TBA dehydration devices.

Carry out cracking preparing isobutene technology about MTBE and TBA compounds, at this stage or blank.One of them is important Reason is that the requirement of MTBE crackers and TBA dehydration devices to catalyst performance is inconsistent.It is generally believed that MTBE cracking and catalyzings The active sites on agent surface are with Bronsted acid（B acid）Based on center, and the catalyst of TBA dehydration preparing isobutenes is Lewis acid （L acid）Catalytic reaction process.For single kind catalyst, either based on B acid or based on L acid, it is impossible to both Take into account.Another reason, using common catalyst, both reaction conditions are different, especially reaction temperature, TBA dehydration temperature Degree is lower compared with MTBE cracking temperatures.Therefore, how to handle MTBE simultaneously under same device same reaction conditions and TBA is mixed Material is closed to produce isobutene, while there is higher activity and selectivity, is an important subject of this area.

The content of the invention

Isobutene is prepared as raw material using MTBE and TBA compounds in order to realize, the invention provides a kind of MTBE and TBA to mix Close the method that material prepares isobutene.This method can not only realize MTBE and TBA simultaneous reactions generation isobutene, and MTBE and TBA is respectively provided with higher conversion ratio, and avoids or reduce the addition of water when MTBE is cracked, and reduces energy consumption of reaction, isobutene reaches To higher selectivity.

The method that MTBE and TBA compounds of the present invention prepare isobutene, using fixed-bed process, at least two series connection Carried out in reactor, previous reactor carries out dehydration using TBA as raw material in the presence of TBA dehydration catalysts, and dehydration is anti- Product after answering enters the latter reactor with MTBE and TBA compounds, is reacted, prepared different in the presence of following catalyst Butylene；Catalyst contains core shell structure component used by wherein latter reactor, and core is amorphous silica-alumina, and shell is by silicon and tin Modified aluminum oxide, wherein being 1 by the weight ratio of the aluminum oxide and amorphous silica-alumina of silicon and tin modification:40~1:4, preferably 1:30 ~1:6；By in the aluminum oxide of silicon and tin modification, silicone content is 0.5wt%~2.0wt%, preferably 0.8wt%~1.5wt%, tin Content is 0.2wt%~1.0wt%, preferably 0.3wt%~0.8wt%.

In the inventive method, in the charging of previous reactor and latter reactor, TBA weight ratio is 1：10~10：1, it is excellent Elect 1 as：8~1：2.

The charging of the latter reactor of the present invention, MTBE and TBA weight ratio is 1 in MTBE and TBA compounds:1~50:1, Preferably 2:1~30:1.The reaction condition of latter reactor is：Temperature is 120 DEG C~300 DEG C, preferably 150 DEG C~250 DEG C； Pressure is normal pressure~0.6MPa, preferably normal pressure~0.3MPa；Volume space velocity is 0.5h during total liquid^-1~10.0h^-1, it is preferably 2.0h^-1~5.0h^-1。

The catalyst of the component containing core shell structure used in the latter reactor of the present invention, in described amorphous silica-alumina, SiO₂Contain Measure as 60.0wt%~99.0wt%, preferably 80.0wt%~95.0wt%, preferably 87.0wt%~93.0wt%；Al₂O₃Content For 1.0wt%~40.0wt%, preferably 5.0wt%~20.0wt%, preferably 7.0wt%~13.0wt%.Amorphous silica-alumina Property is as follows；Specific surface area is 240m²/ g~450m²/ g, preferably 270 m²/ g~410m²/g；Pore volume be 0.4mL/g~ 0.9mL/g, preferably 0.5mL/g~0.7mL/g.

The catalyst of the component containing core shell structure used in the latter reactor of the present invention, the amorphous silica-alumina is preferably using containing work The amorphous silica-alumina of property agent.One or more of the described activating agent in group iia and group VIII metal, wherein the Group IIA metal is preferably the one or more in Be, Mg and Ca, group VIII metal be preferably one kind in Ni, Pd and Pt or It is a variety of.On the basis of the weight of the amorphous silica-alumina containing activating agent, the content of activating agent oxide is 0.3wt%~2.0wt%.

The preparation method of the catalyst of the component containing core shell structure used in the latter reactor of the present invention, including：By chlorosilane and Siliceous and tin aluminum hydroxide slurry is obtained in the aluminum hydroxide slurry that sn-containing compound is added separately to constantly stir, is contained above-mentioned The aluminum hydroxide slurry of silicon and tin is sprayed on amorphous silica-alumina, then through drying and being calcined, obtains catalyst of the present invention.

In above-mentioned method for preparing catalyst, chlorosilane and sn-containing compound are added in the aluminum hydroxide slurry constantly stirred Preferably with the mode for being slowly added to or instilling.

In above-mentioned method for preparing catalyst, used amorphous silica-alumina can use method conventional in the prior art to prepare Amorphous silica-alumina, such as coprecipitation, step-by-step precipitation method and mechanical mixing, preferably obtained after saturated vapor is handled Amorphous silica-alumina, wherein treatment temperature are 150 DEG C~450 DEG C, and processing time is 5h~24h.

In the present invention, the amorphous silica-alumina preferably uses the amorphous silica-alumina containing activating agent.Described activating agent is selected from One or more in group iia and group VIII metal, wherein group iia metal be preferably one kind in Be, Mg and Ca or A variety of, group VIII metal is preferably the one or more in Ni, Pd and Pt.Using the weight of the amorphous silica-alumina containing activating agent as Benchmark, the content of activating agent oxide is 0.3wt%~2.0wt%.Active agent component can be born before saturated steam processing Carry, can also be in the back loading of saturated steam processing, carrying method can use infusion process, and detailed process is as follows：Will be without fixed Shape sial is immersed in the aqueous solution of the soluble inorganic salt containing activating agent, and activator solution concentration is 0.08mol/L~2.0mol/ L, it is calcined 3~8 hours through 200 DEG C~600 DEG C again after dipping.

In above-mentioned method for preparing catalyst, used aluminum oxide is prepared by aluminum hydroxide slurry.Aluminum hydroxide slurry one As use boehmite slurries.Boehmite also known as monohydrate alumina or false boehmite, molecular formula are AlOOH·nH₂O（N=0.08~0.62）.Aluminum hydroxide slurry is prepared using conventional method, including aluminium alcoholates Hydrolyze method, aluminium salt Or acid system or alkaline process, the NaA1O of aluminate₂Solution is passed through CO₂Carbonizatin method etc..

The chlorosilane of the preferred facile hydrolysis of chlorosilane, can be dimethyldichlorosilane, front three in above-mentioned method for preparing catalyst One or more in base chlorosilane, phenyl chlorosilane etc..Wherein, the addition of chlorosilane（In terms of silicon）For aluminium hydroxide（With Aluminum oxide meter）0.5wt%~2.0wt% of weight, preferably 0.8wt%~1.5wt%.

In above-mentioned method for preparing catalyst, the sn-containing compound of the preferred facile hydrolysis of sn-containing compound, including stannous chloride, four One or more in stannic chloride, nitric acid tin, stannous sulfate, stannous octoate, dibutyl tin dichloride etc..Wherein, stanniferous chemical combination The addition of thing（In terms of tin）For aluminium hydroxide（In terms of aluminum oxide）0.2wt%~1.0wt% of weight, preferably 0.3wt%~ 0.8wt%.

The catalyst of the component containing core shell structure is preformed catalyst used in the latter reactor of the present invention.Shaping of catalyst can be with Carried out before siliceous and tin aluminum hydroxide slurry sprays amorphous silica-alumina（For example be first molded amorphous silica-alumina, through drying After roasting, siliceous and tin aluminum hydroxide slurry is sprayed, then final catalyst is obtained after drying and roasting）, can also be Siliceous and tin aluminum hydroxide slurry is carried out after spraying amorphous silica-alumina（For example the siliceous and aluminum hydroxide slurry of tin is sprayed It is dipped on the amorphous silica-alumina without shaping, then after drying or drying and be calcined, then through shaping, dry and roasting, obtains Final catalyst）.The catalyst can use conventional forming method, and suitable size and shape can be made according to actual conditions Shape, such as spherical, bar shaped etc..Spheric catalyst can use oil drop method, rotary type comminution granulation, marumerizer method of forming etc., and its is several What diameter is preferably chosen as 2.0mm-3.0mm between 1.0mm-5.0mm., can be with forming process in the inventive method Binding agent and shaping assistant are added, binding agent can use conventional binding agent, generally small porous aluminum oxide, account for final catalyst 5.0wt%~20.0wt% of weight.Shaping assistant such as sesbania powder or methylcellulose, account for final catalyst weight 1.5wt%~3.0wt%.

It is involved in the preparation process of the catalyst of the component containing core shell structure used in latter reactor in the inventive method The drying and roasting arrived typically are carried out using normal condition, such as drying condition：1h ~ 24h, roasting are dried at 80 DEG C ~ 150 DEG C Condition：1h ~ 24h is calcined at 400 DEG C~700 DEG C, preferably 450 DEG C~600 DEG C.

The inventive method can use conventional reactor, such as using original MTBE cracking preparing isobutene devices or TBA It is dehydrated preparing isobutene device.

The inventive method, the weight ratio for being particularly suitable for handling MTBE and TBA is 1:1~50:1 compound, preferably MTBE with TBA weight ratio is 2:1~30:1.Impurity in compound is that raw material prepares isobutene and TBA is equal to or less than conventional MTBE The impurity contained during raw material dehydration preparing isobutene in raw material, such as methyl sec-butyl ether≤0.2wt%, methanol≤0.05wt%, Isobutylene oligomer≤0.05 wt%, carbon four and carbon hydro carbons≤0.1wt% below four.

The inventive method uses the reactors of at least two series connection, and previous reactor carries out TBA dehydrations, its product with MTBE and TBA compounds enter latter reactor, MTBE and TBA compounds are carried out in the presence of a kind of special catalyst and are split simultaneously Solution prepares isobutene, not only realizes MTBE cracking and TBA is dehydrated two kinds of reactions while carries out generation isobutene, make turning for TBA Rate and MTBE conversion ratio are higher, and also save and add water process in conventional MTBE cracking reactions, reduce energy consumption of reaction, The selectivity for generating isobutene is also higher.

In the preparation process of the catalyst of the component containing core shell structure used in the latter reactor of the present invention, in hydroxide aluminium paste The chlorosilane and sn-containing compound added in liquid is hydrolyzed respectively, and the work of suitable TBA dehydrations can be provided for shell aluminum oxide Property center, while silicon and other groups（Including organic group, acidic-group etc.）Presence have beneficial to improving catalyst shell Pore distribution and shell and the connectivity in stratum nucleare duct, are advantageous to compound and react and be diffused rapidly to stratum nucleare.In addition, chlorine silicon The acid that alkane and sn-containing compound generate when hydrolyzing（Including hydrochloric acid etc.）Also slurry viscosity can be increased, make catalyst structure more equal Even, nucleocapsid combines even closer.The catalyst provides excellent property to process MTBE and TBA compounds simultaneously and preparing isobutene Can, existing catalyst is unable to reach.

The present invention is by synthesizing a kind of raw catelyst, for generating the anti-of isobutene by raw material of MTBE and TBA compounds Ying Zhong, TBA dehydrations is cracked two kinds of reactions with MTBE while carry out preparing isobutene, avoid point of MTBE and TBA compounds From process, and avoid building MTBE crackers respectively and TBA dehydration devices produce isobutene, save operating procedure, reduce Cost of investment, make TBA conversion ratio and MTBE conversion ratio it is higher, and add water step when saving MTBE cracking, reduce anti- It should be able to consume, the selectivity for generating isobutene is also higher.

Embodiment

In the inventive method, TBA dehydration catalysts can use conventional catalyst, azochlorosulfonate acid ion can be used to exchange tree Fat catalyst, aluminium oxide catalyst can also be used.Sulfonic acid ion exchange resin catalyst used, be with sulfonic acid group, The polystyrene of crosslinking, with introducing sulfonic acid group after the concentrated sulfuric acid or chlorosulfonic acid processing after polymerisation.Sulfonic acid ion exchange resin The exchange capacity of catalyst is 3.0mmol/g~6.0mmol/g.Aluminium oxide catalyst used can use conventional aluminum oxide Catalyst.

In the inventive method, previous reactor TBA dehydrations can use conventional process conditions, general as follows：Temperature For 80 DEG C~300 DEG C, pressure is normal pressure~0.6MPa, preferably normal pressure~0.3MPa；Volume space velocity is 0.3h during liquid^-1~ 10.0h^-1, preferably 0.8h^-1~5.0h^-1.Specific process conditions those skilled in the art can be according to selected catalyst Form with raw material and requirement to product determines.In the inventive method, for previous reactor TBA dehydrations, TBA conversion ratio will be at least more than 20wt%, preferably more than 50wt%.

In the present invention, material purity and product form use gas chromatography analysis.Specific surface area and pore volume are using low Warm liquid nitrogen determination of adsorption method.Constituent content is determined using inorganic analysis method.In the present invention, wt% is mass fraction.

Comparative example 1

With the macroporous cross-linked polystyrene-divinylbenzene Archon being polymerized（Diameter 2.6mm）For sulphonated supports, with dichloro Ethane be solvent 50 DEG C be swelled 1.5h after, using sulfur trioxide as sulfonating agent, 80 DEG C react 3.0h, be warming up to 120 DEG C of reactions 1.0h, dichloroethanes is then removed, sulfonic acid ion exchange resin catalyst SZ-1 is made after being washed to neutrality and drying.Its TBA cracking evaluation result is shown in Table 1.

Comparative example 2

By amorphous silicon aluminium powder FM1（Wherein SiO₂Content 92.1wt%, specific surface area 281m²/ g, pore volume are 0.58mL/g）It is immersed in appropriate Ni (NO₃)₂The aqueous solution（Solution concentration is 0.15mol/L）Middle 12h, by 400 DEG C of roasting 6h, then After 300 DEG C, the processing of 6h saturated vapors, obtain containing the amorphous silicon aluminium powder FM1-1 that nickel oxide is 0.61wt%.

By aluminum hydroxide slurry LRJ1（Solid content is 21.3wt%）Spray on FM1-1, dry 4 h at 120 DEG C, 500 6h is calcined at DEG C, the small porous aluminum oxide that then addition weight accounting is 10wt% is molded as adhesive with the marumerizer method of forming For grain size between 2.2mm-2.5 mm catalyst pellet, at 120 DEG C dry 15h, through 450 DEG C roasting 6h be catalyzed Agent DB-1, wherein aluminium hydroxide are counted with the weight of amorphous silica-alumina ratio as 1 using aluminum oxide:10.Specific evaluation result is shown in Table 2.

Comparative example 3

Under agitation, it is sub- that nitric acid tin, octanoic acid are slowly added in the aluminum hydroxide slurry LRJ1 into comparative example 2 respectively Tin, dimethyldichlorosilane, obtain siliceous and tin mixed serum（LRJ1-2）, wherein nitric acid tin and stannous octoate are in terms of tin Addition accounts for boehmite（Aluminium hydroxide）Mole of 0.38wt% in terms of alumina weight, nitric acid tin and stannous octoate Than for 1:1；Addition of the dimethyldichlorosilane in terms of silicon accounts for 1.23wt% of the boehmite in terms of alumina weight.So 4 h are dried at 120 DEG C afterwards, roasting 6h obtains siliceous and tin alumina powder LRJ1-3 at 500 DEG C.

By the FM1-1 in comparative example 2 and LRJ1-3 with weight than 10:1 uniformly mixing, then adding weight accounting is 10wt% small porous aluminum oxide is shaped to grain size between 2.2mm-2.5 mm as adhesive with the marumerizer method of forming Catalyst pellet, 4h is dried at 120 DEG C, catalyst DB-2 is obtained through 400 DEG C of roasting 16h.Specific evaluation result is shown in Table 2.

Comparative example 4

Aluminum hydroxide slurry LRJ1 in comparative example 2 is dried into 4 h at 120 DEG C, 6h is calcined at 500 DEG C, then adds Weight accounting be 10wt% small porous aluminum oxide as adhesive, grain size is shaped in 2.2mm- with the marumerizer method of forming Catalyst pellet between 2.5 mm, 4h is dried at 120 DEG C, catalyst DB-3 is obtained through 400 DEG C of roasting 16h.Specific evaluation knot Fruit is shown in Table 1.

Comparative example 5

The siliceous and tin alumina powder LRJ1-3 that comparative example 3 is obtained, add the aperture that weight accounting is 10wt% and aoxidize Aluminium is shaped to grain size catalyst pellet between 2.2mm-2.5 mm, 120 as adhesive with the marumerizer method of forming 4h is dried at DEG C, catalyst DB-4 is obtained through 400 DEG C of roasting 6h.Specific evaluation result is shown in Table 1.

Comparative example 6

Amorphous silicon aluminium powder FM1-1 in comparative example 2 is added into small porous aluminum oxide of the weight accounting for 10wt% as bonding Agent, grain size catalyst pellet between 2.2mm-2.5 mm is shaped to the marumerizer method of forming, dried at 120 DEG C 4h, catalyst DB-5 is obtained through 450 DEG C of roasting 12h, its MTBE cracking evaluation result is shown in Table 3.

Comparative example 7

Using comparative example 2 and comparative example 3 and the catalyst of embodiment 1, it is in the case of without preposition TBA dehydration catalysts MEBE and TBA cracking evaluation result is shown in Table 4.

Embodiment 1

The aluminum hydroxide slurry LRJ1-2 of stanniferous and silicon in comparative example 3 is sprayed to the amorphous silica-alumina in comparative example 2 On powder FM1-1,4h is then dried at 120 DEG C, 6h is calcined at 500 DEG C.Then the aperture oxygen that weight accounting is 10wt% is added Change aluminium as adhesive, grain size catalyst pellet between 2.2mm-2.5 mm is shaped to the marumerizer method of forming, 4h is dried at 120 DEG C, catalyst SL-1 is obtained through 400 DEG C of roasting 6h, wherein by silicon and the aluminum oxide and amorphous silicon of tin modification The weight ratio of aluminium is 1:10.Specific evaluation result is shown in Table 2.

Embodiment 2

Under agitation, to aluminum hydroxide slurry LRJ2（Solid content 31.2wt%）It is middle be slowly added respectively butter of tin, Trim,ethylchlorosilane.Obtain siliceous and tin mixed serum（LRJ2-2）, wherein addition of the butter of tin in terms of tin account for intend it is thin 0.65wt% of the diaspore in terms of alumina weight；Addition of the trim,ethylchlorosilane in terms of silicon accounts for boehmite with aluminum oxide The 0.85wt% of weight meter.This slurries is sprayed on the amorphous silicon aluminium powder FM1-1 in comparative example 2, then at 90 DEG C 8h is dried, 3h is calcined at 600 DEG C.Then the methylcellulose of small porous aluminum oxide and 2.0wt% that weight accounting is 7.5wt% is added Respectively as adhesive and shaping assistant, grain size is shaped to the marumerizer method of forming and is catalyzed between 2.6mm-2.9 mm Agent bead, at 90 DEG C dry 8h, through 650 DEG C roasting 3h obtain catalyst SL-2, wherein by the aluminum oxide of silicon and tin modification with The weight ratio of amorphous silica-alumina is 1:20.Specific evaluation result is shown in Table 2.

Embodiment 3

By amorphous silicon aluminium powder FM2（Wherein SiO₂Content 82.2wt%, Al₂O₃Content is 17.8wt%；Specific surface area is 335m²/ g, pore volume 0.78mL/g）After 200 DEG C, the processing of 16h saturated vapors, appropriate Be (NO are immersed in₃)₂The aqueous solution （Solution concentration is 1.50mol/L）In, it must contain the amorphous silicon aluminium powder that beryllium oxide is 1.02wt% by 500 DEG C of roasting 5h FM2-1.The mixed serum LRJ1-2 of stanniferous and silicon in comparative example 4 is sprayed on amorphous silicon aluminium powder FM2-1, Ran Hou 1.5h is dried at 150 DEG C, 4h is calcined at 650 DEG C.Then small porous aluminum oxide that weight accounting is 18wt% is added as adhesive, Grain size catalyst pellet between 2.2mm-2.5 mm is shaped to the marumerizer method of forming, 4h, warp are dried at 120 DEG C 400 DEG C of roasting 6h obtain catalyst SL-3, wherein being 1 by the weight ratio of the aluminum oxide and amorphous silica-alumina of silicon and tin modification:25. Specific evaluation result is shown in Table 2.

Embodiment 4

The mixed serum LRJ2-2 of stanniferous and silicon in embodiment 2 is sprayed to the amorphous silicon aluminium powder in embodiment 3 On FM2-1,10h is then dried at 80 DEG C, 6h is calcined at 500 DEG C.Then the small porous aluminum oxide that weight accounting is 5wt% is added And 3.0wt% sesbania powder is shaped to grain size with the marumerizer method of forming and existed respectively as adhesive and shaping assistant Catalyst pellet between 2.4mm-2.7 mm, 4h is dried at 120 DEG C, catalyst SL-4 is obtained through 700 DEG C of roasting 6h, wherein by The weight ratio of the aluminum oxide and amorphous silica-alumina of silicon and tin modification is 1:5.Specific evaluation result is shown in Table 2.

The TBA cracking fixed bed appreciation conditions and result of the comparative example 1,4 and 5 of table 1

	Comparative example 1	Comparative example 4	Comparative example 4	Comparative example 5	Comparative example 5
						Catalyst	SZ-1	DB-3	DB-3	DB-4	DB-4
Volume space velocity during TBA liquid, h-1	1.0	1.0	1.0	1.0	1.0
						Reaction temperature, DEG C	95	265	210	265	210
Reaction pressure, MPa	0.05	0.05	0.05	0.05	0.05
						TBA conversion ratios, wt%	83.5	97.2	91.8	98.5	93.4
The selectivity of isobutene, wt%	99.6	92.5	93.5	84.3	83.8

From table 1, activated alumina catalyst DB-3 and split with the aluminium oxide catalyst DB-4 of silicon tin modification for TBA Xie Shi, catalytic performance when reaction temperature is 265 DEG C are significantly better than catalytic performance when reaction temperature is 210 DEG C.Further, through When the aluminium oxide catalyst crossed after tin, Si modification is used for TBA cracking reactions, TBA conversion ratio is improved, but selectivity is paid no attention to Think.

The fixed-bed process evaluation result of the comparative example 2,3 of table 2 and embodiment 1-4 prepared catalysts

Appreciation condition and result	Comparative example 2	Comparative example 3	Embodiment 1	Embodiment 2	Embodiment 3	Embodiment 4
							First paragraph TBA dehydration reactors
Catalyst	DB-3	DB-3	DB-3	SZ-1	SZ-1	DB-3
							Volume space velocity during TBA liquid, h-1	1.0	1.0	2.0	1.0	1.0	2.0
Reaction temperature, DEG C	210	210	210	105	95	155
							Reaction pressure, MPa	0.05	0.05	0.05	0.05	0.05	Normal pressure
Second segment MTBE and TBA compound crack
							Catalyst	DB-1	DB-2	SL-1	SL-2	SL-3	SL-4
Volume space velocity during MTBE liquid, h-1	4.0	4.0	4.0	3.5	2.3	3.0
							Volume space velocity during TBA liquid, h-1（Fresh feed）	0.5	0.5	0.5	0.5	1.0	2.0
Reaction temperature, DEG C	210	210	210	210	210	155
							Reaction pressure, MPa	0.05	0.05	0.05	0.05	0.05	Normal pressure
MTBE conversion ratios, wt%	97.1	98.4	99.9	99.8	99.7	97.0
							TBA conversion ratios, wt%	91.0	92.5	99.6	99.7	99.9	98.3
Selective isobutene, wt%	99.2	99.3	99.8	99.9	99.8	99.7

As can be seen from Table 2, using the present invention technical process, and use new catalyst provided by the invention i.e. with The catalyst that the aluminum oxide of silicon and tin modification is shell, amorphous silica-alumina is core, it can not only realize MTBE cracking and TBA dehydrations two Kind reaction carries out generating isobutene reaction process, and the conversion ratio with higher MTBE and TBA, the selectivity of isobutene simultaneously It is higher, illustrate that the inventive method can efficiently control the generation of side reaction.

Meanwhile the nucleocapsid catalyst only prepared using unmodified aluminum oxide as shell, itself MTBE and TBA conversion ratio is not Height, the selectivity of isobutene are also poor；Even if modified activated aluminum oxide and amorphous silica-alumina are mixed to prepare into catalyst, although MTBE and TBA conversion ratio, selective isobutene increases, but still undesirable.

The MTBE cracking fixed bed appreciation conditions and result of the comparative example 6 of table 3

	Comparative example 5	Comparative example 5
			Catalyst	DB-5	DB-5
Volume space velocity during MTBE liquid, h-1	2.5	2.0
			Volume space velocity during aqueous, h-1	0.1	0.1
Reaction temperature, DEG C	230	210
			Reaction pressure, MPa	Normal pressure	0.05
MTBE conversion ratios, wt%	99.6	98.2
			The selectivity of isobutene, wt%	99.2	99.3

As can be seen from Table 3, when amorphous silicon Al catalysts are used for MTBE cracking, catalysis when reaction temperature is 230 DEG C Performance is significantly better than catalytic performance when reaction temperature is 210 DEG C.

MTBE the and TBA compounds cracking fixed bed appreciation condition and result of the comparative example 7 of table 4

Catalyst	DB-1	DB-2	SL-1
				Volume space velocity during total liquid, h-1	4.5	4.5	4.5
Volume space velocity during MTBE liquid, h-1	4.0	4.0	4.0
				Volume space velocity during TBA liquid, h-1	0.5	0.5	0.5
Reaction temperature, DEG C	210	210	210
				Reaction pressure, MPa	0.05	0.05	0.05
MTBE conversion ratios, wt%	97.0	98.3	99.3
				TBA conversion ratios, wt%	91.3	92.9	99.5
Selective isobutene, wt%	99.0	99.2	99.6

From table 4, it can be seen that the nucleocapsid catalyst prepared using unmodified aluminum oxide as shell, modified activated aluminum oxide and nothing Amorphous silicon-alumina is mixed to prepare catalyst, is exclusively used in the catalyst of MTBE and TBA compounds cracking, if a not preposition TBA is dehydrated Journey, its conversion ratio and selective isobutene do not reach the embodiment of table 2 level.

Claims (16)

1. a kind of method that MTBE and TBA compounds prepare isobutene, using fixed-bed process, in the reaction of at least two series connection Carried out in device, previous reactor carries out dehydration using TBA as raw material in the presence of TBA dehydration catalysts, after dehydration Product and MTBE and TBA compounds enter the latter reactor, reacted in the presence of following catalyst, prepare isobutyl Alkene；Catalyst contains core shell structure component used by wherein latter reactor, and core is amorphous silica-alumina, and shell is to be changed by silicon and tin Property aluminum oxide, wherein by silicon and tin modification aluminum oxide and amorphous silica-alumina weight ratio be 1:40~1:4, changed by silicon and tin In the aluminum oxide of property, silicone content is 0.5wt%~2.0wt%, and Theil indices are 0.2wt%~1.0wt%.

2. in accordance with the method for claim 1, it is characterised in that：Catalyst contains core shell structure used by latter reactor The aluminum oxide of component, silicon and tin modification and the weight ratio of amorphous silica-alumina are 1:30~1:6, by silicon and the aluminum oxide of tin modification In, silicone content is 0.8wt%~1.5wt%, and Theil indices are 0.3wt%~0.8wt%.

3. in accordance with the method for claim 1, it is characterised in that：Catalyst used by latter reactor, described nothing are determined In shape sial, SiO₂Content is 60.0wt%~99.0wt%, Al₂O₃Content is 1.0wt%~40.0wt%.

4. in accordance with the method for claim 1, it is characterised in that：The amorphous silica-alumina property is as follows；Specific surface area is 240m²/ g~450m²/ g, pore volume are 0.4mL/g~0.9mL/g.

5. in accordance with the method for claim 1, it is characterised in that：The amorphous silica-alumina uses the amorphous silicon containing activating agent Aluminium, wherein one or more of the described activating agent in group iia and group VIII metal, group iia metal are Be, Mg With the one or more in Ca, group VIII metal is the one or more in Ni, Pd and Pt, with the amorphous silicon containing activating agent On the basis of the weight of aluminium, the content of activating agent oxide is 0.3wt%~2.0wt%.

6. in accordance with the method for claim 1, it is characterised in that：In the charging of latter reactor, MTBE and TBA weight ratio For 1:1~50:1.

7. in accordance with the method for claim 6, it is characterised in that：In the charging of latter reactor, MTBE and TBA weight ratio For 2:1~30:1.

8. in accordance with the method for claim 1, it is characterised in that：In the charging of previous reactor and latter reactor, TBA's Weight ratio is 1：10~10：1.

9. in accordance with the method for claim 8, it is characterised in that：In the charging of previous reactor and latter reactor, TBA's Weight ratio is 1：8~1：2.

10. in accordance with the method for claim 1, it is characterised in that：The reaction condition of latter reactor is：Temperature is 120 DEG C ~300 DEG C, pressure is normal pressure~0.6MPa, and volume space velocity is 0.5h during total liquid^-1~10.0h^-1。

11. in accordance with the method for claim 10, it is characterised in that：The reaction condition of latter reactor is：Temperature is 150 DEG C ~250 DEG C, pressure is normal pressure~0.3MPa, and volume space velocity is 2.0h during total liquid^-1~5.0h^-1。

12. in accordance with the method for claim 1, it is characterised in that：In the compound of latter reactor, methyl sec-butyl ether≤ 0.2wt%, methanol≤0.05wt%, isobutylene oligomer≤0.05wt%, carbon four and carbon hydro carbons≤0.1wt% below four.

13. in accordance with the method for claim 1, it is characterised in that：TBA dehydration catalysts are urged using sulfonic acid ion exchange resin Agent or using aluminium oxide catalyst.

14. in accordance with the method for claim 1, it is characterised in that：The process conditions of previous reactor TBA dehydrations are such as Under：Temperature is 80 DEG C~300 DEG C, and pressure is normal pressure~0.6MPa, and volume space velocity is 0.3h during liquid^-1~10.0h^-1。

15. in accordance with the method for claim 1, it is characterised in that：For previous reactor TBA dehydrations, TBA conversion Rate will be at least more than 20wt%.

16. in accordance with the method for claim 15, it is characterised in that：For previous reactor TBA dehydrations, TBA's turns Rate will be at least more than 50wt%.