The preparation method of TS-1 HTSs
Technical field
The invention belongs to inorganic chemical synthesis technical field, and in particular to a kind of HTS, i.e. TS-1 titaniums silicon molecule
The preparation method of sieve.
Background technology
TS-1 molecular sieves are a kind of catalysis green woods with unique MFI topological structures of twentieth century exploitation at the beginning of the eighties
Material, be in a kind of skeleton silicon atom by the partially substituted heteroatoms zeolite molecular sieve of titanium atom.Wherein, titanium atom is equal in skeleton
Even distribution and form the skeleton Si-O-Ti keys with special nature, it has three-dimensional open-framework using ZSM-5 as representative, by Z
Font passage and intersecting therewith oval straight channel are formed.The mid-80 is successfully developed by Italian Enichem companies
And in the industrial production for being applied to caprolactam intermediate-cyclohexanone oxime in 1994.TS-1 can be catalyzed low concentration hydrogen peroxide and enter
The many selective oxidation reactions of row, the epoxidation of such as alkene, phenol hydroxylation, benzene hydroxylation, ammoxidation of cyclohexanone reaction.Its
In, TS-1 as selective oxidation of new generation Green Chemistry new catalyst in phenol hydroxylation preparing benzenediol, cyclohexanone ammonia oxygen
Change the fields such as preparing cyclohexanone oxime and realized industrialized production, there is good industrial prospect.
Existing much applications on TS-1 molecular sieve preparation methods in the prior art.Nineteen eighty-three, Italian scientist
Taramasso et al. makes public for the first time the method for preparing TS-1 molecular sieves in patent GB207071A, USP4,410,501, its
Material molar ratio composition such as table 1.
The raw material composition that TS-1 is synthesized in the patent US4,410,501 of table 1
|
Mol ratio |
Optimum mole ratio |
SiO2/TiO2 |
5-200 |
35-65 |
OH-/SiO2 |
0.1-1.0 |
0.3-0.6 |
H2O/SiO2 |
20-200 |
60-100 |
Me/SiO2 |
0.0-0.5 |
0 |
RN+/SiO2 |
0.1-2.0 |
0.4-1.0 |
, need to be without CO but methods experiment condition in the prior art is more harsh2Atmosphere, and hydrothermal crystallizing time
It is long.
Thangaraj et al. thinks the cumbersome of above-mentioned synthesis TS-1 molecular sieves, into skeleton effective titanium content very
Few, condition is difficult to control, and experimental repeatability is poor, and then their open report in 1992 proposes two kinds of synthesis roads for preparing TS-1
Line (Zeolites, 1992, Vol.12, p943~950), Thangaraj is using the weaker butyl titanate of hydrolysing activity
(TBOT) the stronger tetraethyl titanate (TEOT) of hydrolysing activity is replaced, while introduces aqueous isopropanol and it is diluted to delay
Hydrolysis rate, and prehydrolysis processing is carried out to tetraethyl orthosilicate (TEOS), match both hydrolysis rates, to improve molecular sieve titanium
Content.This method turns into the basis of hereafter two TS-1 classics hydrothermal synthesis methods during the last ten years, on this basis, both domestic and external to grind
Study carefully scholar and use in this method more and titanium esters diluent is done with isopropanol, replaces TEOT to do titanium source with TBOT, slow down titanium ester hydrolysis
Speed, to reduce Detitanium-ore-type TiO2Generation etc..
Wang Xiang lifes et al. disclose the fast synthesis method (CN1401569A) of a kind of nanometer of titanium-silicon molecular sieve catalyst, are
Exchanged with homemade 4-propyl bromide (TPABr) through strongly basic anionic resin, be concentrated to give TPAOH
(TPAOH) aqueous solution is template, and tetraethyl orthosilicate (TEOS) is silicon source, and butyl titanate (TBOT) reacts for titanium source.The party
Titanium esters and estersil need to be hydrolyzed respectively in method, and hydrolysis time needs strict control, and the TS-1 crystalline sizes of gained are too small (to be only had
100nm or so) and wherein the process such as subsequent filter, washing is very difficult to operate in the industrial production.
Above-mentioned representational TS-1 synthetic methods, have that the hydrothermal crystallizing time is long, experimental repeatability is poor, and operation is numerous
It is trivial, be unfavorable for the shortcomings of industrial production.Because Hydrothermal Synthesiss solvent group is complicated, both contains isopropanol, contain TBOT and TEOS again
The butanol and ethanol of generation are hydrolyzed, is unfavorable for recycling in production and environmentally friendly.Simultaneously because experimental repeatability is poor, it is difficult to controls
The crystal habit of TS-1 molecular sieves.
In cyclohexanone oximate and the industrial production of alkene epoxidation, the TS-1 molecular sieves of generally use zeolite MFI structure
As catalyst, the molecular sieve forms by the Z-type duct parallel to α axles and parallel to the straight hole road intersection of b axles, it is however generally that,
The straight advantageous transmission and diffusion in molecule in it of pore size, and Z-shaped pore size is relatively small is beneficial to realize molecule
Shape selective catalysis.The particle size of molecular sieve has considerable influence with pattern to its catalytic performance.
Zeolite molecular sieve is because the presence of micropore, and often limited reactions thing and product molecule be in its inner transmission matter and diffusion,
Cause to influence catalyst activity.This problem can shorten diffusion path and come gram by directly reducing the thickness of molecular sieve crystal
Clothes.TS-1 is applied to H earliest2O2For the Italian Enichem companies in the cyclohexanone oxamidinating novel environment-friendly process of oxidant
Pointed out in (former Montedipe companies) official website, be that TS-1 molecular sieves contain high skeleton Ti, urged with height with typical " blackberry, blueberry shape "
Change the feature (http of activity://www.eni.com/en_IT/attachments/azienda/attivita-strategie/
petrolchimica/licensing/TS1-A4-lug09.pdf).Therefore, the present invention is by controlling crystallizing reaction solution
TPAOH concentration changes the pattern of TS-1 molecular sieve crystals, and then controls a/b- shaft lengths, so as to effectively controlling it in alkene
Catalytic performance in hydrocarbon ring oxidation and cyclohexanone oximation reaction.
In the method for preparing TS-1 molecular sieves of prior art, complicated reaction system, template costliness, hydro-thermal are still suffered from
The problems such as crystallization time is long, experimental repeatability difference.
The present inventor have passed through substantial amounts of experiment and find, by being accurately controlled template in the step of catching up with alcohol
Concentration and change in concentration, the control of more preferable pattern can be realized in the case where adding small amount template.Based on this
It was found that inventor completes the present invention.
The content of the invention
It is therefore an object of the present invention to provide a kind of preparation method of TS-1 HTSs.
According to an embodiment of the invention, it provides a kind of preparation method of TS-1 HTSs, this method
Using formula (R1O)4The tetraalkyl esters of silicon acis of Si structures is as organic silicon source, using formula (R2O)4The tetraalkyl titanate of Ti structures
As organic titanium source, wherein, R1And R2For the alkyl and R of 2~4 carbon atoms1=R2, this method comprises the following steps:
1) hydrolyze
With molar ratio computing, according to the SiO in silicon source2:TiO in titanium source2:Template:H2O is 1:(0.01~0.08):
(0.05~0.4):The ratio of (10~25) prepares reaction mixture solution, and reactant mixture is entered under the conditions of 20~70 DEG C
Water-filling solution 3~5 hours;
Wherein, the template is TPAOH,
Preferably, in this step, the configuration reaction mixture solution includes adding organic titanium source in organic silicon source
It is well mixed, the mixed solution of titanium source and silicon source is slowly added dropwise with vigorous stirring water-soluble to the template diluted in proportion
In liquid,
2) alcohol is caught up with
The reactant mixture obtained in step 1) is warming up to 70~95 DEG C, alcohol is caught up with 2~6 hours, adds during alcohol is caught up with
Adding deionized water so that template change in concentration value in reaction mixture is within ± 10%,
Preferably, the concentration of the TPAOH is 5~10wt%;
3) crystallization
Hydrothermal crystallizing temperature is 175~240 DEG C, and the hydrothermal crystallizing time is 1~8 hour, in a stationary situation or can be stirred
Crystallized under the conditions of mixing;
4) filter, wash, dry and be calcined
Product is filtered after the crystallization that upper step is obtained, washs, dries and after 500 to 600 DEG C are calcined 3~6 hours, system
TS-1 HTSs are obtained,
Preferably, the pattern of the TS-1 HTSs be blackberry, blueberry form, average particle size particle size be 200nm~300nm.
Preferably, in step 1), the SiO in silicon source2:TiO in titanium source2:Template:H2O is 1:(0.02~0.05):(0.15~
0.25):(18~25);Hydrolysis temperature is 30~60 DEG C, and hydrolysis time is 3~4 hours;
Preferably, in step 2), temperature is 75~90 DEG C, and the reaction time is 3.5~5 hours, TPAOH
Concentration be 6~9wt%;
Preferably, in step 3), hydrothermal crystallizing temperature is 175~200 DEG C, and the hydrothermal crystallizing time is 2~4 hours;
Preferably, in step 4), roasting time is 3~5 hours,
Be advantageous to obtain the spy of the molecular sieve crystal of preferable pattern in hydrothermal crystallization process for relatively low template agent concentration
Point, the present invention is during second step catches up with alcohol and catching up with makes the TPAOH concentration in reaction system be 5~10wt% after alcohol, from
And obtain the TS-1 crystal with blackberry, blueberry pattern.The 3rd step crystallization temperature of the present invention uses when being higher than prior art hydrothermal crystallizing
Temperature, so as to produce higher self-generated pressure, beneficial to the formation of TS-1 nucleus, shorten the hydrothermal crystallizing time, improve life
Efficiency is produced, reduces production cost.
Compared with prior art, the technology of the present invention has following remarkable advantage:
1st, the isopropanol for replacing using in traditional TS-1 synthesis with estersil is protected to titanium esters, avoids introducing isopropanol,
Simplify reaction system, reduce production cost;
2nd, the hydrothermal crystallizing time most short foreshortens to 1 hour;
3rd, due to 1,2 the characteristics of, production efficiency significantly improves when synthesizing TS-1 molecular sieves using the technology of the present invention, is produced into
Originally it is greatly lowered;
4th, the inventive method synthesis TS-1 granular sizes are easily controllable, pattern is in blackberry, blueberry form, there is good catalysis
Oxidative function.
Therefore there is the characteristics of cost is low, catalyst performance is good using present invention production TS-1 molecular sieves, these features are non-
Often be advantageous to the commercial Application of the molecular sieve.
Brief description of the drawings
Fig. 1 is the molecular sieve SEM electron microscopic pictures that embodiment 1 synthesizes.
Fig. 2 be embodiment it is 2-in-1 into molecular sieve SEM electron microscopic pictures.
Fig. 3 is the molecular sieve SEM electron microscopic pictures that embodiment 3 synthesizes.
Fig. 4 is the molecular sieve SEM electron microscopic pictures that comparative example 1 synthesizes.
Fig. 5 be comparative example it is 2-in-1 into molecular sieve SEM electron microscopic pictures.
Embodiment
Embodiment 1
Organic silicon source and organic titanium source are respectively TEOS and TEOT
First one-step hydrolysis
SiO in (mol ratio) silicon source in proportion2:TiO in titanium source2:Template:H2O is 1:0.05:0.22:25, match somebody with somebody
Reaction mixture solution processed:First TEOT is added in TEOS and is well mixed, with vigorous stirring by TEOS and TEOT mixed solutions
It is slowly added dropwise to by template:H2O is 0.22:25 ratio (SiO2Mol ratio is in the TPAOH aqueous solution 1) diluted.All
Reactant mixture after being added dropwise is hydrolyzed 5 hours under the conditions of 35 DEG C;
Second step catches up with alcohol
Reaction mixture is warming up to 80 DEG C after the titanium silicon that upper step is handled is hydrolyzed, and catches up with alcohol 4 hours, and alcohol is being caught up with according to calculating
During deionized water is added dropwise, be basically unchanged with the template agent concentration ensured in reaction mixture, specifically, changing value is
Within ± 10%, wherein TPAOH concentration is 6.3% (wt).
3rd step crystallization
Static hydrothermal crystallization temperature is 200 DEG C, and the hydrothermal crystallizing time is 2 hours.
The filtering of 4th step, washing, dry and be calcined
Product is filtered after the crystallization that upper step is obtained, washs, dries and is calcined 4 hours at 550 DEG C, obtains TS-1 titanium silicon
Molecular sieve catalyst A1.
The SEM Electronic Speculum of TS-1 molecular sieves is shown in accompanying drawing 1.
Embodiment 2
Organic silicon source and organic titanium source are respectively TEOS and TEOT
First one-step hydrolysis
SiO in (mol ratio) silicon source in proportion2:TiO in titanium source2:Template:H2O is 1:0.04:0.25:20, match somebody with somebody
Reaction mixture solution processed:First TEOT is added in TEOS and is well mixed, with vigorous stirring by TEOS and TEOT mixed solutions
It is slowly added dropwise to by template:H2O is 0.25:20 ratio (SiO2Mol ratio is in the TPAOH aqueous solution 1) diluted.All
Reactant mixture after being added dropwise is hydrolyzed 3 hours under the conditions of 45 DEG C;
Second step catches up with alcohol
Reaction mixture is warming up to 75 DEG C after the titanium silicon that upper step is handled is hydrolyzed, and catches up with alcohol 5 hours, and alcohol is being caught up with according to calculating
During deionized water is added dropwise, be basically unchanged with the template agent concentration ensured in reaction mixture, specifically, changing value is
Within ± 10%, wherein TPAOH concentration is 8.1% (wt).
3rd step crystallization
Static hydrothermal crystallization temperature is 200 DEG C, and the hydrothermal crystallizing time is 2 hours.
The filtering of 4th step, washing, dry and be calcined
Product is filtered after the crystallization that upper step is obtained, washs, dries and is calcined 4 hours at 550 DEG C, obtains TS-1 titanium silicon
Molecular sieve catalyst A2.
The SEM Electronic Speculum of TS-1 molecular sieves is shown in accompanying drawing 2.
Embodiment 3
Organic silicon source and organic titanium source are respectively the positive butyl ester of silicic acid four and butyl titanate (TBOT).
First one-step hydrolysis
SiO in (mol ratio) silicon source in proportion2:TiO in titanium source2:Template:H2O is 1:0.04:0.245:19, match somebody with somebody
Reaction mixture solution processed:First TBOT is added in the positive butyl ester of silicic acid four and is well mixed, with vigorous stirring by TBOT and positive silicon
Sour four butyl ester mixed solutions are slowly added dropwise to by template:H2O is 0.245:19 ratio (SiO2Mol ratio is 1) to have diluted
In the TPAOH aqueous solution.Reactant mixture after being all added dropwise is hydrolyzed 3 hours under the conditions of 60 DEG C;
Second step catches up with alcohol
Reaction mixture is warming up to 90 DEG C after the titanium silicon that upper step is handled is hydrolyzed, and catches up with alcohol 4 hours, and alcohol is being caught up with according to calculating
During deionized water is added dropwise, be basically unchanged with the template agent concentration ensured in reaction mixture, specifically, changing value is
Within ± 10%, wherein TPAOH concentration is 6.7% (wt).
3rd step crystallization
Dynamic Hydrothermal crystallization temperature is 200 DEG C, and the hydrothermal crystallizing time is 2 hours.
The filtering of 4th step, washing, dry and be calcined
Product is filtered after the crystallization that upper step is obtained, washs, dries and is calcined 4 hours at 550 DEG C, obtains TS-1 titanium silicon
Molecular sieve catalyst A3.
The SEM Electronic Speculum of TS-1 molecular sieves is shown in accompanying drawing 3.
Comparative example 1
Except for the following differences, remaining is the same as embodiment 2 for implementation process.Obtain TS-1 titanium-silicon molecular sieve catalysts B1.
Catch up with and control rate of water make-up during alcohol, so that TPAOH concentration is 15.5% in the template in reaction mixture
(wt)。
The SEM Electronic Speculum of TS-1 molecular sieves is shown in accompanying drawing 4.
Comparative example 2
Except controlling rate of water make-up during alcohol is caught up with, so that TPAOH concentration is in template in reaction mixture
7.5% (wt), i.e. catch up with the TPAOH concentration after alcohol beyond original template agent TPAOH concentration 6.3% 19% beyond, with embodiment
1 identical mode prepares TS-1 titanium-silicon molecular sieve catalysts B2.
The SEM Electronic Speculum of obtained TS-1 molecular sieves is shown in accompanying drawing 5.
EXPERIMENTAL EXAMPLE
The catalytic performance test for the TS-1 molecular sieves that the present invention synthesizes.
The catalytic oxidation performance of TS-1 molecular sieves is evaluated using cyclohexanone oxamidinating reaction.Specific operation process is:
First disposable TS-1 catalyst, cyclohexanone, ammoniacal liquor and the tert-butyl alcohol, the condensing reflux of adding is warming up to 60 in there-necked flask
DEG C, H is then added dropwise2O2(time for adding is more than 30 minutes), 4h is finally reacted at 60 DEG C, reaction solution cold filtration, yield is by GC
Analysis.Reactant ratio is:1gTS-1 catalyst, 4.41g cyclohexanone, the 4.80g tert-butyl alcohols, 22.35g ammoniacal liquor (30wt%),
16.33g hydrogen peroxide (10wt%), n (H2O2)/n (cyclohexanone)=1.07, n (NH3)/n (cyclohexanone)=4.26, GC detections use
External standard method.
Catalytic applications of the HTS in cyclohexanone oximation reaction the results are shown in Table 2.
Evaluation result of the HTS of table 2 in cyclohexanone oximation reaction
Sample number into spectrum |
Cyclohexanone conversion ratio (%) |
Cyclohexanone oxime selectivity (%) |
A1 |
97.54 |
99.70 |
A2 |
97.80 |
99.94 |
A3 |
98.09 |
99.89 |
B1 |
97.60 |
93.90 |
B2 |
97.62 |
95.47 |
Oximes evaluating data is found in each embodiment gained TS-1 molecular sieve SEM pictures and table 2 in comparative drawings figs, crystallization
Step TPAOH concentration control in the range of 6~10%, can obtain pattern be blackberry, blueberry form, average particle size particle size be 200nm or so
Titanium-silicon molecular sieve catalyst, and cyclohexanone oxamidinating evaluation in show that there is good catalysis oxidation function.
In comparative example 1, when TPAOH concentration is 15.5% in the template in crystallization steps reaction mixture
(wt) when, the TS-1 molecular sieve B1 crystallite dimensions of gained are bigger than normal, about 600nm or so, the cyclohexanone oxime choosing of its oximes evaluation
Selecting property only has 93.90%, hence it is evident that the evaluation result less than A1~A3.
In comparative example 2, when the template TPAOH change in concentration in crystallization steps reaction mixture is larger,
The TS-1 molecular sieve B2 crystallite dimensions of gained are bigger than normal, and about 500nm or so, the cyclohexanone oxime of its oximes evaluation selectively only has
95.47%, hence it is evident that the evaluation result less than A1~A3.
Photocatalyst crystals morphological observation
Morphologic observation:Appropriate TS-1 sieve samples powder is taken to use strength gas after sample system is complete as on sample stage adhesive tape
Stream, which is blown away, bonds unstable powder, and metal spraying makes its surface conductive, observed under Hitachi S-4800 ESEMs
Sample crystals form.As can be seen that Fig. 1~Fig. 3 sample A1 (embodiment 1), A2 (embodiment 2), A3 (embodiment 3) crystal shape
State is in standard " blackberry, blueberry " shape, epigranular, about in 200nm-300nm or so.Fig. 4 (comparative example 1) crystal B1 forms
Approximate sphericity, surface slightly texture, particle diameter is larger, about in 500nm-600nm or so.Fig. 5 (comparative example 2) crystal B2 shapes
State approximate sphericity, surface texture is less, and particle diameter is larger, about in 400nm-500nm or so.