CN102060307B - Method for preparing titanium-silicon molecular sieve - Google Patents

Abstract

The invention relates to a method for preparing a titanium-silicon molecular sieve, which is technically characterized by comprising the following steps of: mixing a solid inorganic silicon source and an inorganic titanium source in the molar ratio that Si:Ti=(40-80):1; carrying out ball milling to the mixture for 50-100h on a ball mill at the rotation speed of 500-700turns/min; adding a tetrapropylammonium bromide (TPABr) aqueous solution into a titanium-silicon precursor product subjected to ball milling to obtain a mixture with the molar ratio of Si to Ti to TPABr to H2O being 1:(0.0125-0.025):(0.05-0.3):(10-40); crystallizing the mixture for 3-5 days with a hydrothermal process in a sealed reaction kettle at 150-190 DEG C under the condition of stirring; and then, carrying out filtering, washing, drying and roasting according to the conventional method to obtain the TS-1 molecular sieve. The method has the advantages of low cost, simplicity in operation and high product stability.

Description

A kind of preparation method of HTS

Technical field

The present invention relates to a kind of preparation method of HTS, relate to the method that a kind of low cost prepares HTS (TS-1) catalyzer, particularly be equipped with the titanium silicon precursor, make the method for HTS (TS-1) then with the mechanical ball milling legal system.

Background technology

U.S. Pat P4410501 (nineteen eighty-three) discloses the compound method of the HTS (TS-1) with MFI structure.Its key step is that silicon source, titanium source and template are processed presoma, and the hydrothermal method crystallization is 6～30 days in 130～200 ℃ autoclave, obtains TS-1 through separation, washing, drying and roasting then.In preparation presoma process; Because the titanic acid ester hydrolysis rate in used titanium source is faster than the silicon ester hydrolysis rate in silicon source in the raw material; Therefore when dropping is fast slightly as TPAOH (TPAOH) solution speed of template, will produce the polymer of irreversible titanium.The polymer of these titaniums is difficult to get into framework of molecular sieve in crystallization process, but is distributed in the molecular sieve to be mingled with form, has both stopped up molecular sieve pore passage, causes hydrogen peroxide decomposition again, thereby makes the catalytic activity of molecular sieve reduce.

To the problems referred to above; Chinese patent ZL 02125738.8 (2002) proposes alkoxyl silicone hydrolysis under acidity or alkaline condition, and then with titanium source and aqueous isopropanol adding, make alkoxyl silicone and titanium source complete hydrolysis after; Add TPAOH in the stirring; Obtain titanium colloidal silica mixture, add water and in sealed reactor, carried out crystallization 2～5 days afterwards, reclaim product at last.Though this method can be controlled the hydrolysis in titanium source; Improve the titanium content in the skeleton, but this method is not enough below existing: repeatedly occur hydrolytic process in the operating process, need to judge whether hydrolysis is complete; Therefore operating process is numerous and diverse; Influence factor is numerous, causes the TS-1 quality of final preparation stable inadequately, and repeatability is relatively poor; Still be template with expensive TPAOH, and the use of TPAOH is the high one of the main reasons of TS-1 molecular sieve cost always, therefore this method synthetic TS-1 cost is higher.

Summary of the invention

The technical problem that solves

For fear of the weak point of prior art, the present invention proposes a kind of preparation method of HTS, overcomes insufficient problems such as prior art complicated operating process, repeatable poor, production cost height.Can make HTS, simultaneously prepared MFI type HTS good reproducibility simply fast, low-cost.

Technical scheme

A kind of preparation method of HTS is characterized in that step is following:

Step 1: will prepare burden according to the ratio of mol ratio Si: Ti=40～80: 1 as the solid-state silicon-dioxide of the amorphous in inorganic silicon source with as the anatase titanium dioxide of inorganic ti sources;

Step 2: the powder that step 1 is prepared carries out ball milling on ball mill, and ball milling condition is 500～700 rev/mins of rotating speeds, 50～100 hours ball milling time, prepares the titanium silicon precursor;

Step 3: in the titanium silicon precursor, add the 4-propyl bromide aqueous solution, wherein the mol ratio Si of mixture: H ₂O is 1: 10～40, and mol ratio Si: TPABr is 1: 0.05～0.3;

Step 4: with step 3 gained mixture hydrothermal method crystallization in the reaction kettle of sealing, crystallization temperature is 150～190 ℃; The rotating speed of crystallization process stirring rotator is 15～35 rev/mins, and crystallization time is 3～5 days;

Step 5: the mixture that step 4 is carried out crystallization cleans, and at room temperature after the drying, 500～550 ℃ of following roastings 6～9 hours, obtains HTS.

The drying temperature of step 5 is 80～110 ℃.

Beneficial effect

The preparation method of a kind of HTS that the present invention proposes; The requirement of its condition control is so not strict; Method with mechanical ball milling has replaced traditional chemical process to prepare the titanium silicon precursor, has simplified operation steps, has improved repeatability; Overcome insufficient problems such as prior art complicated operating process, repeatable poor, production cost height, be easy in industry, use; And silicon source and titanium source are inexpensive and obtain easily; Adopt cheap 4-propyl bromide to replace expensive TPAOH, make the synthetic cost of product significantly reduce, can make HTS, simultaneously prepared MFI type HTS good reproducibility simply fast, low-cost as template.

Description of drawings

Fig. 1: be X ray diffracting spectrum according to method synthetic TS-1 provided by the invention

Embodiment

Combine embodiment, accompanying drawing that the present invention is further described at present:

Embodiment 1

Weighing 7.9 gram amorphous silicas and 0.2 gram anatase titanium dioxide, in the planetary silicon nitride ceramics ball milling jar of packing into, the silicon nitride ball of packing into simultaneously., after 50 hours gained titanium silicon precursor is changed in the reaction kettle with 500 rev/mins speed ball millings, in reaction kettle, add simultaneously the aqueous solution of 4-propyl bromide (TPABr), make the mol ratio Si of mixture in the reaction kettle: TPABr=1: 0.05, Si: H ₂O=1: 10.This mixture in the reaction kettle was stirred crystallization 3 days under 170 ℃ of autogenous pressures, stirring velocity is 35 rev/mins in the crystallization.After crystallization finishes, reactant is taken out, filter, washing, 80 ℃ dry 6 hours down, roasting 6 hours in 530 ℃ then, the TS-1 molecular sieve that obtains has the X ray diffracting spectrum shown in the accompanying drawing 1.

Embodiment 2～4

Instance 2～4th, purpose mainly are the repeatability of investigating building-up process, according to the condition and the step of instance 1, repeat synthesis technique fully, all can obtain the TS-1 molecular sieve at last.

Embodiment 5

Weighing 8.5 gram amorphous silicas and 0.2 gram anatase titanium dioxide, in the planetary silicon nitride ceramics ball milling jar of packing into, the silicon nitride ball of packing into simultaneously.Ball grinder is with 550 rev/mins speed ball milling after 55 hours; Gained titanium silicon precursor is changed in the reaction kettle; The aqueous solution that in reaction kettle, adds simultaneously 4-propyl bromide (TPABr) makes the mol ratio Si of mixture in the reaction kettle: TPABr=1: 0.05, and Si: H ₂O=1: 10.This mixture was stirred crystallization 3 days at 170 ℃ under the power of boosting, stirring velocity is 35 rev/mins in the crystallization.After crystallization finishes, reactant is taken out, filter, washing, 80 ℃ dry 6 hours down, roasting 6 hours in 530 ℃ then obtains the TS-1 molecular sieve.

Embodiment 6

7.9 gram amorphous silicas and 0.2 gram anatase titanium dioxide are packed in the silicon nitride ceramics ball milling jar; With 500 rev/mins speed ball millings after 50 hours; Gained titanium silicon precursor is changed in the reaction kettle; The aqueous solution that in reaction kettle, adds simultaneously 4-propyl bromide (TPABr) makes the mol ratio Si of mixture in the reaction kettle: TPABr=1: 0.1, and Si: H ₂O=1: 15.This mixture was stirred crystallization 4 days at 170 ℃ under the power of boosting, stirring velocity is 35 rev/mins.After crystallization finishes, reactant is taken out, filter, washing, 80 ℃ dry 6 hours down, roasting 7 hours in 540 ℃ then obtains the TS-1 molecular sieve.

Embodiment 7

With 7.9 gram amorphous silicas and the 0.2 gram anatase titanium dioxide planetary silicon nitride ceramics ball milling jar of packing into, the silicon nitride ball of packing into simultaneously., after 70 hours gained titanium silicon precursor is changed in the reaction kettle with 500 rev/mins speed ball millings, in reaction kettle, add simultaneously the aqueous solution of 4-propyl bromide (TPABr), make the mol ratio Si of mixture in the reaction kettle: TPABr=1: 0.1, Si: H ₂O=1: 15.This mixture was stirred crystallization 3 days at 190 ℃ under the power of boosting, stirring velocity is 30 rev/mins.After crystallization finishes, reactant is taken out, under filtration, washing, the room temperature dry 12 hours, roasting 6 hours in 540 ℃ then obtained the TS-1 molecular sieve.

Embodiment 8

Weighing 8.5 gram amorphous silicas and 0.2 gram anatase titanium dioxide; Pack in the planetary silicon nitride ceramics ball milling jar;, after 70 hours gained titanium silicon precursor is changed in the reaction kettle with 600 rev/mins speed ball millings, in reaction kettle, add the aqueous solution of 4-propyl bromide (TPABr) simultaneously; Make the mol ratio Si of mixture in the reaction kettle: TPABr=1: 0.2, Si: H ₂O=1: 20.This mixture was stirred crystallization 3 days at 170 ℃ under the power of boosting, stirring velocity is 25 rev/mins.After crystallization finishes, reactant is taken out, under filtration, washing, the room temperature dry 12 hours, roasting 6 hours in 550 ℃ then obtained the TS-1 molecular sieve.

Embodiment 9

Weighing 7.9 gram amorphous silicas and 0.2 gram anatase titanium dioxide; Pack in the planetary silicon nitride ceramics ball milling jar;, after 80 hours gained titanium silicon precursor is changed in the reaction kettle with 550 rev/mins speed ball millings, in reaction kettle, add the aqueous solution of 4-propyl bromide (TPABr) simultaneously; Make the mol ratio Si of mixture in the reaction kettle: TPABr=1: 0.3, Si: H ₂O=1: 30.This mixture was stirred crystallization 3 days at 190 ℃ under the power of boosting, stirring velocity is 20 rev/mins.After crystallization finishes, reactant is taken out, under filtration, washing, the room temperature dry 12 hours, roasting 7 hours in 540 ℃ then obtained the TS-1 molecular sieve.

Embodiment 10

This instance is mainly investigated the effect that adopts instance 1 prepared TS-1 molecular sieve catalytic phenol hydroxylation to react.Reaction conditions is following:

1.0 gram TS-1,20 gram phenol, 33 gram acetone and 2.4 gram hydrogen peroxide are mixed the following 80 ℃ of waters bath with thermostatic control heating of magnetic agitation condition 6 hours in having the three-necked flask of prolong.Reacted product adopts the analysis of Alltech 426 type high performance liquid chromatographs.Operational condition is: adopt the C18 chromatographic column, solvent is the mixed solution of first alcohol and water, and wherein the methyl alcohol volume content is 70%, and water accounts for 30%, and solvent flow rate is 1ml/min.Adopt ultra-violet analysis, selected wavelength is 254nm.

Analytical results shows: phenol conversion is 21.22%, and the dihydroxy-benzene selectivity is 99.37%.

Claims (1)

1. the preparation method of a HTS is characterized in that step is following:

Step 1: will prepare burden according to the ratio of mol ratio Si: Ti=40～80: 1 as the solid-state silicon-dioxide of the amorphous in inorganic silicon source with as the anatase titanium dioxide of inorganic ti sources;

Step 2: the powder that step 1 is prepared carries out ball milling on ball mill, and ball milling condition is 500～700 rev/mins of rotating speeds, 50～100 hours ball milling time, prepares the titanium silicon precursor;

Step 3: in the titanium silicon precursor, add the 4-propyl bromide aqueous solution, wherein the mol ratio Si of mixture: H ₂O is 1: 10～40, and mol ratio Si: TPABr is 1: 0.05～0.3;

Step 4: with step 3 gained mixture hydrothermal method crystallization in the reaction kettle of sealing, crystallization temperature is 150～190 ℃; The rotating speed of crystallization process stirring rotator is 15～35 rev/mins, and crystallization time is 3～5 days;

Step 5: the mixture that step 4 is carried out crystallization cleans, and at room temperature after the drying, 500～550 ℃ of following roastings 6～9 hours, obtains HTS.

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