CN100379492C

CN100379492C - Super alkali composite catalyst for preparing superfine KF/Al2O3 using Sol-gel method

Info

Publication number: CN100379492C
Application number: CNB2005100231810A
Authority: CN
Inventors: 顾明兰
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-01-10
Filing date: 2005-01-10
Publication date: 2008-04-09
Anticipated expiration: 2025-01-10
Also published as: CN1803284A

Abstract

With the wide application of solid super-strong basic catalysts, and the production of high-quality catalysts by a simple process is necessary; the traditional process adopts a load method to produce composite KF/Al2O3 super-strong basic catalysts which have the disadvantages of easy agglomeration, large particle size, non-uniform effective ingredient distribution, complicated production process and high energy consumption. The present invention adopts a sol-gel method to synthesize superfine composite KF/Al2O3 super-strong basic catalysts by one step, overcomes the defects of the traditional production method; produced superfine composite KF/Al2O3 super-strong basic catalysts have the advantages of small particle size of about 300 to 500 nm, large surface area, uniform distribution of effective ingredients, simple production process and energy resource saving; KF/Al2O3 is widely used in reactions, such as an alkylation reaction, Michael, Henry, Knoevenagel, Perkin, Claisen -Schmidt, etc. due to the strong effective catalytic activity; the KF/Al2O3 is easily separated from products; the reactive specificity is high, and research and development persons pay more attention to the KF/Al2O3; the present invention adopts the Knoevenagel condensation reaction as the probe reaction of the catalysts, which nicely controls the quality of the catalysts.

Description

With the standby ultra-fine KF/Al of Sol-gel legal system 2O 3The super base composite catalyst

Technical field

The present invention is with the standby ultra-fine KF/Al of Sol-gel legal system ₂O ₃A kind of method of super base composite catalyst.

Background technology

KF/Al ₂O ₃Because its strong effectively catalytic activity is widely used in the reactions such as alkylated reaction, Michael, Henry, Knoevenagel, Perkin, Claisen-Schmidt.And KF/Al ₂O ₃Be easier to separating of product, the selectivity of reaction is very high, more and more is subjected to scientific research personnel's attention.

Generally prepare super basic catalyst KF/Al with load method at present ₂O ₃: KF is soluble in water, add neutral Al ₂O ₃(chromatography usefulness, 100～200 orders) in 65 ℃ of stirring reaction 1h, then with Rotary Evaporators with the water evaporate to dryness, solid namely obtains support type KF/Al at 120 ℃ of dry 4h ₂O ₃Catalyst.The content of KF is generally 40%.The shortcoming of this load method is: the KF of adding can not load to Al fully equably ₂O ₃On.And the granularity of gained catalyst is big, and surface area is big, lack of homogeneity.

As everyone knows, it is more even that the effective ingredient of catalyst is disperseed, and specific surface is more big, and its catalytic efficiency is more high, so prepared sizes are little, surface area is big, finely dispersed KF/Al ₂O ₃Catalyst is necessary.

Summary of the invention

It is lower that the Sol-gel process has reaction temperature, and can be from the initial period of material processed, just structure and the character to material is controlled on molecular scale, can also introduce certain composition quantitatively, may so provide for the uniform composite of the ultra-fine level of preparation.

The present invention's Sol-gel method is at synthetic Al ₂O ₃, process in KF is mixed into, thereby successfully prepared ultra-fine super basic catalyst KF/Al ₂O ₂: aluminium isopropoxide is dispersed in the toluene solution with ultrasonic wave, obtains solution A; A certain amount of KF2H that will mix ₂O is dissolved in aluminium isopropoxide and quantitatively is hydrolyzed in the required water, behind the dissolve complete, adds a small amount of isopropyl alcohol, obtains solution B; Start stirring and slowly solution A is splashed in the solution B, dropwise, continue hydrolysis; After reacting completely, cooling, suction filtration, drying, calcining can obtain the loose powder of 300～500nm.

The present invention compares difference with traditional handicraft and is:

1) traditional handicraft: at first prepare Al ₂O ₃, then KF is loaded on Al ₂O ₃On, drying, calcining (activation), this building-up process needs twice dry twice calcining (to produce Al ₂O ₃Process also need drying, calcining); The present invention can obtain KF/Al with one-step synthesis ₂O ₃Catalyst: at synthetic Al ₂O ₃Process in directly KF is mixed into, then dry, calcining.This building-up process does not only need primary drying, calcination process, has greatly saved the energy, and technology is simple, and equipment requirement is low, more easily realizes industrialization, thereby production cost descends.

2) KF/Al of traditional handicraft ₂O ₃In the production process of catalyst, KF can only physical absorption (or passing through hydrogen bond) at Al ₂O ₃On, and just mix by mechanical agitation, effective ingredient skewness, resulting catalyst are easier to reunite, granularity big (micron order), and surface area is little, and catalytic effect is poor; The present invention is producing Al ₂O ₃Process in KF is mixed into, KF is evenly dispersed in Al ₂O ₃On, and the KF/Al that obtains of Sol-gel method ₂The O powder granularity is little, and (300～500nm), the difficult reunion, surface area is big, and catalytic effect obviously improves.

Present invention is described below in conjunction with example.

Example 1:

Under sonic oscillation, 20.4g (0.1mol) aluminium isopropoxide is dissolved in the 200ml toluene fully, forms clear solution, start mechanical agitator, this solution is slowly splashed into by the water of 5.4g (0.3mol), the KF2H of 2g ₂In the system that O and 7ml isopropyl alcohol are formed.Dropwise, be warming up to 60 ℃ of times, continue reaction 3h.Obtain translucent gels or suspension liquid, filter, at 60 ℃ of lower dry 12h, 120 ℃ of dry 1h, the powder that can obtain loosening at 450 ℃ of lower calcining 3h, can obtain the ultra-fine KF/Al of 300～400nm ₂O ₃Compound super basic catalyst.The present invention contracts with Knoevenagel and reacts (benzaldehyde and ethyl cyanoacetate contract and obtain 2-cyanogen-3-ethyl phenylacrylate) as probe reaction.The catalyst effect of example 1 preparation: 2-cyanogen-3-ethyl phenylacrylate yield is 91.5%.

Example 2:

Under sonic oscillation, 20.4g (0.1mol) aluminium isopropoxide is dissolved in the 200ml toluene fully, forms clear solution, start mechanical agitator, this solution is slowly splashed into by the water of 5.4g (0.3mol), the KF2H of 2.5g ₂In the system that O and 7ml isopropyl alcohol are formed.Dropwise, be warming up to 70 ℃ of times, continue reaction 4h.Obtain translucent gels or suspension liquid, filter, at 60 ℃ of lower dry 12h, 120 ℃ of dry 1h, the powder that can obtain loosening at 525 ℃ of lower calcining 3h, can obtain the ultra-fine KF/Al of 400～500nm ₂O ₃Compound super basic catalyst.The catalyst effect of example 2 preparations: 2-cyanogen-3-ethyl phenylacrylate yield is 88.5%.

Example 3:

Under sonic oscillation, 20.4g (0.1mol) aluminium isopropoxide is dissolved in the 200ml toluene fully, forms clear solution, start mechanical agitator, this solution is slowly splashed into by the water of 5.4g (0.3mol), the KF2H of 2.5g ₂In the system that O and 7ml isopropyl alcohol are formed.Dropwise, be warming up to 40 ℃ of times, continue reaction 3h.Obtain translucent gels or suspension liquid, filter, at 60 ℃ of lower dry 12h, 120 ℃ of dry 1h, the powder that can obtain loosening at 600 ℃ of lower calcining 3h, can obtain the ultra-fine KF/Al of 410～500nm ₂O ₃Compound super basic catalyst.The catalyst effect of example 3 preparations: 2-cyanogen-3-ethyl phenylacrylate yield is 91.5%.

Claims

1. ultra-fine KF/Al that form is loose ₂O ₃The preparation method of compound super basic catalyst, its preparation process comprises: 1) aluminium isopropoxide is dispersed in the toluene solution with ultrasonic wave, obtains solution A; A certain amount of KF2H that 2) will mix ₂O is dissolved in aluminium isopropoxide and quantitatively is hydrolyzed in the required water, behind the dissolve complete, adds a small amount of isopropyl alcohol, obtains solution B; 3) start stirring and slowly solution A is splashed in the solution B, dropwise, continue hydrolysis; 4) react completely after, the cooling, suction filtration, drying, the calcining, can obtain the loose powder of 300～500nm.

2. a kind of ultra-fine KF/Al according to claim 1 ₂O ₃The preparation method of compound super basic catalyst is characterized in that: the aluminium isopropoxide toluene system is added drop-wise in the aqueous systems, and the mol ratio of aluminium isopropoxide and water is 1: 3.

3. a kind of ultra-fine KF/Al according to claim 1 ₂O ₃The preparation method of compound super basic catalyst is characterized in that: the mass ratio of added water and isopropyl alcohol is 1: 1.

4. a kind of ultra-fine KF/Al according to claim 1 ₂O ₃The preparation method of compound super basic catalyst is characterized in that: the temperature that continues hydrolysis is 40～80 ℃, and the time is 2～5h.

5. a kind of ultra-fine KF/Al according to claim 1 ₂O ₃The preparation method of compound super basic catalyst is characterized in that: dry run is 60 ℃ of dry 12h of normal pressure at first, again at the dry 2h of high temperature of 120 DEG C.

6. a kind of ultra-fine KF/Al according to claim 1 ₂O ₃The preparation method of compound super basic catalyst is characterized in that: calcining heat is 300～600 ℃, and the time is 3h.