CN100558461C - Flake structure titanium silicon molecular sieve propylone direct opoxidation catalyst and preparation method - Google Patents

Abstract

The invention discloses a kind of flake structure titanium silicon molecular sieve propylone direct opoxidation catalyst and preparation method.It is characterized in that, with non-acid SiO ₂Be carrier, contain the HTS of following general formula: xTiO ₂(1-x) SiO ₂Said catalyst has intensity and product diffusion, difficult drop-off preferably.55 ℃ of reaction temperatures, carry out the epoxidation reaction of propylene and hydrogen peroxide under the reaction pressure 0.7Mpa condition, its hydrogen peroxide conversion ratio can reach 94.5%, the selectivity of expoxy propane can reach 91.0%, 100 hours continuity test shows that propylone direct opoxidation catalyst has stability preferably simultaneously, obtained effect preferably, but commercial Application.

Description

Flake structure titanium silicon molecular sieve propylone direct opoxidation catalyst and preparation method

Technical field

The present invention relates to a kind of propylone direct opoxidation catalyst.

Background technology

With TS-1 (titanium silicalite-1) is that the Ti-Si zeolite of representative can make alkene initial ring oxidation reaction generate epoxides in conjunction with the hydrogen peroxide in rare hydrogen peroxide, make phenyl ring generation hydroxylating generate phenol or benzenediol, make cyclohexanone generation ammoxidation reaction generate cyclohexanone oxime, make alcohols generation selective oxidation reaction generate aldehydes or ketones, above-mentioned catalytic reaction is carried out the reaction condition gentleness usually under room temperature or the liquid-solid phase condition a little more than room temperature.Because the no corrosion contamination of titanium-silicon molecular sieve catalyst itself, can regenerate and use repeatedly, what hydrogen peroxide reaction back was remaining is water, so HTS is broken away from the existing intrinsic problem of environmental pollution of industrial technology opportunity is provided for developing the production new technique of oxygen-bearing organic matter.

It is the method that the TS-1 HTS is synthesized in the template agent that U.S. Pat Patent 4410501 has introduced with TPAOH.Utilize said method to synthesize its complicated operating process of TS-1, the reaction time long (6-30 days), and be difficult to avoid the tetraethyl titanate hydrolysis and be polymerized to non-body phase anatase.Yet generally with the synthetic HTS of hydro-thermal method since its crystal grain less than 1 micron, thereby catalyst is difficult to separate and reclaim.

In order to address this problem, U.S. Pat 4701428 had once been reported the method by the HTS of spray drying method for preparation carrierization, yet its particle diameter of catalyst with this method preparation only is about 20 microns, and granularity is not very even, still can not be used for fixing bed bioreactor on a large scale.

Japan Patent JP8103659 is coated with the last layer HTS by the spherical surface at the silicon bead, Dalian University of Technology also adopts the bead with certain mechanical strength as carrier, forming method by the spin granulation has prepared thin layer catalyst, make active component at the carrier surface enrichment like this, active component is utilized, though its reaction effect is better, through improvement several times, coming off of catalyst is a problem that can not be ignored.

Catalytic action in the downstream of catalyst pores (inner-diameter portion whose), the side reaction that usually can cause the accessory substance that is harmful to and take place not expect takes place, the cylindrical catalyst that general HTS is obtained with the extruded moulding method is used for the propylone direct opoxidation reaction, if HTS crystal grain is too little, molecular sieve comes off when reaction easily; If crystal grain is too big, then product is difficult for diffusing out in the duct of catalyst, at the inner deep reaction that further takes place of catalyst, makes the expoxy propane selectivity lower.

Summary of the invention

The technical issues that need to address of the present invention are to disclose a kind of flake structure titanium silicon molecular sieve propylone direct opoxidation catalyst and preparation method, too little to overcome synthetic in the past HTS crystal grain, the shortcoming that is difficult to commercial Application, it is excessive and product diffusion problem that cause makes the low problem of selectivity of product also to have solved simultaneously crystal grain.

Propylone direct opoxidation catalyst of the present invention is with non-acid SiO ₂Be carrier, contain the HTS of following general formula: xTiO ₂(1-x) SiO ₂

Wherein: x is with molar ratio computing, x=Ti/ (Ti+Si), the span 0.003～0.05 of x;

By weight percentage, carrier S iO ₂The amount that accounts for total catalyst levels is 10%～50%;

Said non-acid SiO ₂Refer to SiO ₂Weight concentration is the alkaline silica sol of 20%-40%, preferred SiO ₂Weight concentration is 30% alkaline silica sol, and the preferable range of x is 0.02-0.04.

According to the preferred scheme of the present invention, also comprise extrusion aid;

For improving activity of such catalysts and selectivity, HTS is chosen the flaky texture that big or small homogeneous has six prisms, and its size is in 1～10 μ m * 0.4～2 μ m * 0.1～2 mu m range;

Said HTS can adopt at publication number, and to be that CN1751996 is described improve its titanium source stability with complexing agent to stablize the synthesis of titanium silicon molecular sieve method synthetic;

Said extrusion aid is the sesbania powder, boric acid or its both mixtures, and by weight percentage, the weight of extrusion aid accounts for the 0.5-5% of catalyst;

The preparation method of the propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve of the present invention comprises the steps: HTS, extrusion aid, boric acid, carrier and wetting agent are mixed the back extruded moulding, 105～120 ℃ of oven dry down, pelletizing, then at 180～220 ℃, 280～320 ℃, the difference roasting is 1.5～3 hours under 380～420 ℃ and 580～620 ℃, and 1.5～3 hours, 1.5～3 hours and 5.5～6.5 hours;

Used wetting agent is selected from water or the concentration nitric acid less than 2mol/L; By weight percentage, the weight of wetting agent accounts for the 0.5-5% of catalyst;

The above-mentioned catalyst granules that makes is surveyed granule strength on the KC-1A type granule strength analyzer that Jiangyan City, Jiangsu analytical instrument factory produces, simultaneously catalyst is ground and sieve into 20-40 order catalyst, carrying out the propylone direct opoxidation reaction in caliber is 16 millimeters continuous fixed bed reactors investigates, adopt the concentration of hydrogen peroxide in indirect iodometric determination reaction feed liquid and the product, the GC-920 type gas chromatograph analytical reactions product that use is produced by the glad chromatograph in sea, Shanghai is formed, and detects the capillary chromatographic column with HP-1 (50m * 0.32 * 1.05).

The reaction principal product is an expoxy propane, and accessory substance is propylene glycol monomethyl ether and propane diols, and reaction result adopts following evaluation index:

H ₂O ₂Conversion ratio $X_{H_2{O}_2}=\frac{c_{H_2{O}_2}^0-c_{H_2{O}_2}^i}{c_{H_2{O}_2}^0}\×100\%---\left(1\right)$

The PO selectivity: $S_{\mathrm{PO}}=\frac{n_{\mathrm{PO}}}{n_{\mathrm{PO}}+n_{\mathrm{NME}}+n_{\mathrm{PG}}}\×100\%---\left(2\right)$

In the formula

With

Be respectively the mass concentration of reaction front and back hydrogen peroxide, n _PO, n _NMEAnd n _PGBe respectively reaction back expoxy propane, the amount of substance that propylene glycol monomethyl ether and propane diols generate.As the index of evaluation response performance,

S _PO, y _POAdopt reaction after 6 hours, every 2 hours test samples, three scale errors that make continuous three sample test sample results were less than 2%, simultaneously with the mean value of these three sample result as the reactivity worth index.

Among the present invention since with HTS as the catalyst activity component, with SiO ₂Mix as carry changing, extruded moulding, the particle diameter of catalyst can be regulated as required, to meet the needs that the commercial fixed bed reactor is used, make the propylone direct opoxidation reaction after, avoided the catalyst separation problem.Owing to added carrier S iO in the catalyst ₂After, reduced the effective active component of every gram catalyst, the treating capacity of catalyst is descended to some extent, but because the homogeneous and the flaky texture of the crystalline form of catalyst, make intensity and product diffusion, the difficult drop-off preferably of having of catalyst.55 ℃ of reaction temperatures, carry out the epoxidation reaction of propylene and hydrogen peroxide under the reaction pressure 0.7Mpa condition, its hydrogen peroxide conversion ratio can reach 94.5%, the selectivity of expoxy propane can reach 91.0%, 100 hours continuity test shows that propylone direct opoxidation catalyst has stability preferably, has obtained effect preferably simultaneously.

The specific embodiment

The following examples will the present invention is further illustrated.In following each example, it is that a kind of method with complexing agent raising titanium source stability synthesis of titanium silicon molecular sieve described in the CN1751996 is synthetic that used HTS adopts publication number, synthesize by economic raw material, hydrothermal synthesis method, brilliant material size is 10 μ m * 1.8 μ m * 0.4 μ m; Used carrier S iO ₂Be Ludox portion of Shanghai Atomic Nucleus Inst., Chinese Academy of Sciences product, all the other reagent are commercially available chemically pure reagent.

Embodiment 1

HTS 15 grams are restrained with extrusion aid sesbania powder 0.75 earlier, and after boric acid 0.3 gram mixed, adding its weight concentration of carrier was 30% (SiO ₂) regular grade Ludox 4.5ml, adding 2ml water simultaneously is wetting agent, in mortar, grind evenly after, with the banded extruder extrusion molding good after, dry back pelletizing Φ 2 * 2mm down at 110 ℃, then at 200 ℃, 300 ℃, the difference roasting is 2 hours under 400 ℃ and 600 ℃, and 2 hours, 2 hours and 6 hours.Wherein each component relative weight ratio is in the precursor: HTS: sesbania powder: boric acid: carrier S iO ₂=1: 0.05: 0.02: 0.108

Catalyst ground sieve into 20-40 order catalyst, carrying out the propylone direct opoxidation reaction in caliber is 16 millimeters continuous fixed bed reactors investigates, its appreciation condition is: loaded catalyst is 6 grams, two ends are sealed with quartz sand, and raw material hydrogen peroxide is solvent with methyl alcohol, and the hydrogen peroxide mass percentage concentration is 2.17%, the mol ratio of control charging propylene and hydrogen peroxide is 2.5: 1,55 ℃ of reaction temperatures are 0.7Mpa by nitrogen pressure to reaction pressure, and the liquid inlet amount is 6ml/min.Reaction evaluating result and catalyst strength test result see Table 1.

Embodiment 2

Method for preparing catalyst such as example 1, wherein the relative weight of each component ratio is:

HTS: sesbania powder: boric acid: carrier S iO ₂=1: 0.05: 0.05: 0

The evaluating catalyst condition is seen example 1, and reaction evaluating result and catalyst strength test result see Table 1.

Embodiment 3

Method for preparing catalyst such as example 1 are that rare nitric acid of 1mol/L is wetting agent with its molar concentration of 2ml, and wherein the relative weight of each component ratio is: HTS: sesbania powder: boric acid: carrier S iO ₂=1: 0.02: 0.03: 0.173

The evaluating catalyst condition is seen example 1, and reaction evaluating result and catalyst strength test result see Table 1.Continuous running reaction unit, from the reaction successive reaction sample analysis after 100 hours that picks up counting, reaction result sees Table 1.

Embodiment 4

Method for preparing catalyst such as example 1, wherein the relative weight of each component ratio is:

HTS: sesbania powder: boric acid: carrier S iO ₂=1: 0.01: 0.05: 0.245

The evaluating catalyst condition is seen example 1, and reaction evaluating result and catalyst strength test result see Table 1.

Embodiment 5

Method for preparing catalyst such as example 1, wherein the relative weight of each component ratio is:

HTS: sesbania powder: boric acid: carrier S iO ₂=1: 0.05: 0: 0.331

The evaluating catalyst condition is seen example 1, and reaction evaluating result and catalyst strength test result see Table 1.

Embodiment 6

Method for preparing catalyst such as example 1 are changed to electronic-grade silica sol with the regular grade Ludox, and other are constant, and wherein the relative weight of each component ratio is:

HTS: sesbania powder: boric acid: carrier S iO ₂=1: 0: 0.05: 0.427

The evaluating catalyst condition is seen example 1, and reaction evaluating result and catalyst strength test result see Table 1.

Table 1 propylone direct opoxidation catalyst granule strength and epoxidation reaction result

Embodiment

1

2

3

3 *

4

5

6

Hydrogen peroxide conversion ratio %	94.5	99.3	92.6	90.3	90.7	75.6	43.5
								Expoxy propane selectivity %	91.0	63.9	91.3	90.5	91.5	93.7	97.9
Granule strength N/cm	25.3	5.6	45.7	--	52.3	58.9	65.1

Annotate 3 ^*Reaction result refers to react the mean value of surveying three sample results every 2 hours continuously that records after 100 hours

Claims (7)

1. the propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve is characterized in that, with non-acid SiO ₂Be carrier, contain the HTS of following general formula: xTiO ₂(1-x) SiO ₂

Wherein: x is with molar ratio computing, x=Ti/ (Ti+Si), the span 0.003～0.05 of x;

By weight percentage, carrier S iO ₂The amount that accounts for total catalyst levels is 10%～50%;

Described catalyst does not contain white carbon black.

2. the propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve according to claim 1 is characterized in that, non-acid SiO ₂Ludox for alkalescence.

3. the propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve according to claim 1, it is characterized in that, HTS is chosen the flaky texture that big or small homogeneous has six prisms, and its size is in 1～10 μ m * 0.4～2 μ m * 0.1～2 mu m range.

4. the propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve according to claim 1, it is characterized in that, also comprise extrusion aid, said extrusion aid is the sesbania powder, boric acid or its both mixtures, by weight percentage, the weight of extrusion aid accounts for the 0.5-5% of catalyst.

5. the propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve according to claim 1 is characterized in that, the scope of x is 0.02-0.04.

6. the method for each described propylone direct opoxidation catalyst based on flake structure titanium silicon molecular sieve of preparation claim 1～5, comprise the steps: HTS, extrusion aid, carrier and wetting agent are mixed the back extruded moulding, 105～120 ℃ of oven dry down, pelletizing, then at 180～220 ℃, 280～320 ℃, 380～420 ℃ and 580～620 ℃ are descended roasting respectively 1.5～3 hours, 1.5～3 hours, 1.5～3 hours and 5.5～6.5 hours.

7. method according to claim 6 is characterized in that, said wetting agent is selected from water or the concentration nitric acid less than 2mol/L; By weight percentage, the weight of wetting agent accounts for the 0.5-5% of catalyst.