CN100490971C - Oxide catalyst for dehydrogenating ethyl benzene to prepare styrene - Google Patents

Abstract

The present invention relates to one kind of oxide catalyst for dehydrogenating ethyl benzene to prepare styrene and aims at raising the styrene selectivity and stability of catalyst and reducing toluene as the side product. The technological scheme of the present invention includes adding the combined oxide of Zr, Sn and at least one of Ca, Mn and W into the Fe-K-Ce-Mo catalyst system. The catalyst system may be used in the industrial production of dehydrogenating to produce styrene.

Description

The oxide catalyst that is used for ethyl benzene dehydrogenation preparation of styrene

Technical field

The present invention relates to a kind of oxide catalyst that is used for ethyl benzene dehydrogenation preparation of styrene.

Background technology

The industrial cinnamic manufacturing overwhelming majority realizes by ethylbenzene catalytic dehydrogenation, catalyst system therefor basic composition is major catalyst, co-catalyst and pore-foaming agent, reinforcing agent etc.The Fe-K-Ce-Mo catalyst series that early 1980s succeeds in developing substitutes Cr with Ce, Mo, make catalyst keep on the basis of original stability, activity has raising by a relatively large margin, adopted by countries in the world production of styrene producer, as laid-open U.S. Patents 5190906,4804799, world patent 09839278A1, but also exist selectivity of styrene not high, by-product benzene, toluene level are more, bring difficulty for principal product output and later separation step.Report the iron oxide catalyst that contains noble metal as laid-open U.S. Patents 6177602, used this catalyst can obtain higher benzene/methylbenzene ratio.The toluene level height also is a criterion of examination catalyst performance in the final products, because the accessory substance benzene subsequent technique that is used for capable of circulation that produces, and toluene is undesirable accessory substance, generally sold, therefore, under other identical situation, preferentially select the less catalyst of by-product toluene for use.But used noble metal in the United States Patent (USP) 6177602, expense is higher, is difficult to realize commercial Application.

Summary of the invention

Technical problem to be solved by this invention is that the catalyst by-product toluene that exists in the conventional art is many, selectivity of styrene is low and the problem of poor stability.A kind of new oxide catalyst that is used for ethyl benzene dehydrogenation preparation of styrene is provided.This catalyst have by-product toluene in effective reduction production process growing amount, increase substantially the characteristics of styrene yield and good stability.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of oxide catalyst that is used for ethyl benzene dehydrogenation preparation of styrene, form by binding agent and active component, wherein the addition of binding agent is 1～6% of a total catalyst weight in Preparation of catalysts, and active component is made up of following component by weight percentage:

(a) 60～86% Fe ₂O ₃

(b) 6～12% K ₂O;

(c) 6～12% CeO ₂

(d) 0.5～5% MoO ₃

(e) 0.5～2% ZrO ₂

(f) 0.5～4% SnO ₂

(g) 0.05～5% at least a oxide that is selected from Ca, Mn, W;

(h) 0.5～8% MgO.

In the technique scheme, by weight percentage, magnesian content preferred version is 0.5～3.0%.

The used raw material of the catalyst component that the present invention relates to is as follows:

Fe ₂O ₃Be made up of iron oxide red and iron oxide yellow, its proportioning is Fe ₂O ₃: Fe ₂O ₃H ₂O=0.1～5: 1 is preferably 0.5～2.5: 1.Used K adds with sylvite or hydroxide form, used Ce adds with oxide, hydroxide or cerium salt form, and Mo adds with its salt or oxide form, and Ca adds with its salt or oxide form, W adds with its salt or oxide form, and remaining element adds with oxide form.

In preparation process, also should add perforating agent and binding agent at catalyst of the present invention except that the main body composition, perforating agent can be selected from graphite, polystyrene microsphere, carboxymethyl cellulose, and its addition is 2～8% of a total catalyst weight; Binding agent can be selected from kaolin, diatomite or cement, and its addition is 1～6% of a total catalyst weight.

Method for preparing catalyst of the present invention is as follows:

After other co-catalyst component, binding agent and the perforating agent that will add by Fe, K, Ce, Mo and the need of proportioning weighing mixes, add proper amount of deionized water, make the face dough of toughness, suitable extrusion, becoming diameter through extrusion, pelletizing is 3 millimeters, long 8～10 millimeters particle, in 80～120 ℃ of dryings 4 hours, 500～1000 ℃ of following roastings 4 hours, just can obtain finished catalyst then.

The catalyst that makes as stated above carries out activity rating in the isotherm formula fixed bed, the summary process is as follows:

With ethylbenzene and deionized water preheating in the measuring pump input mixer respectively, enter reactor with gaseous form, reactor adopts the heating wire heating, makes it to reach predetermined temperature.Reactor inside diameter is 1 " stainless steel tube, it is interior that to load 100 milliliters, particle diameter be 3.0 millimeters catalyst.Analyzing it with gas chromatograph by the dehydrogenation product of reactor outflow behind water condensation forms.

The evaluating catalyst condition is as follows in the isotherm formula fixed bed reactors: 100 milliliters of catalyst are put into internal diameter 1 " isothermal reactor, reaction pressure is normal pressure, liquid air speed 1.0 hours ^-1, 620 ℃ of reaction temperatures, water be than (weight) 2.0.Evaluation result sees Table 1,2.

Catalyst is accelerated burn-in test, also carries out in the isotherm formula fixed bed reactors.The catalysis aging method is the quick means that the catalyst stability energy is judged in the laboratory.It is to adopt extreme reaction condition to make catalyst rapid deactivation at short notice, and deactivation rate is slow more, shows that catalyst stability is good more.For made the styrene reaction by ethylbenzene dehydrogenation, extreme condition is high temperature, high-speed, low water ratio, accelerates aging condition among the present invention and is: 640 ℃ of reaction temperatures, water be than (weight) 1.60, liquid air speed 6.0 hours ^-1Catalyst is accelerated the degradation data and is seen Table 3.

Conversion of ethylbenzene and selectivity of styrene calculate as follows:

The present invention is by having added zirconium, tin and at least a combination of oxides that is selected from calcium, manganese, tungsten in iron-potassium-cerium-molybdenum system, be surprised to find made dehydrogenation and have that by-product toluene is few, selectivity of styrene is high and the outstanding advantage of good stability, obtained better technical effect.

The invention will be further elaborated below by embodiment.

The specific embodiment

[embodiment 1]

250.8 gram iron oxide reds, 140.0 gram iron oxide yellows, 76.0 gram potash, 80.7 gram cerous nitrates, 9.8 gram ammonium molybdates, 5.0 magnesia, 1.0 gram zirconias, 8.0 gram tin oxide, 5.0 gram manganese oxide, 8.9 gram calcium carbonate and 16.5 gram cement, 16.2 gram carboxymethyl celluloses were stirred in kneader 1 hour, add deionized water, mix and stir half an hour again, take out extrusion, be extruded into the particle of 3 millimeters of diameters, 8～10 millimeters of length, put into baking oven, in 80 ℃ of bakings 2 hours, 120 ℃ were dried by the fire 2 hours, place roaster then, made catalyst in 4 hours in 900 ℃ of roastings.The preparation method of all the other embodiment is with embodiment 1, and inventory changes to some extent, and is specific as follows:

Gained catalyst composed as follows:

The same embodiment of the method for preparing catalyst of comparative example, concrete inventory is:

Gained catalyst composed as follows:

The contrast of table 1 catalyst performance

The dehydrogenation product of each catalyst of table 2 distributes

Aging data are accelerated in 500 hours of table 3 embodiment 2 catalyst

Above embodiment explanation, in the Fe-K-Ce-Mo system, add zirconium, tin and at least a combination of oxides that is selected from calcium, manganese, tungsten, add perforating agent, binding agent, made dehydrogenation has that by-product toluene is few, selectivity of styrene is high and the outstanding advantage of good stability, helping factory and improve styrene output, increase economic benefit, is a kind of novel dehydrogenation.

Claims (7)

1, a kind of oxide catalyst that is used for ethyl benzene dehydrogenation preparation of styrene, form by binding agent and active component, wherein the addition of binding agent is 1～6% of a total catalyst weight in Preparation of catalysts, and active component is made up of following component by weight percentage:

(a) 60～86% Fe ₂O ₃

(b) 6～12% K ₂O;

(c) 6～12% CeO ₂

(d) 0.5～5% MoO ₃

(e) 0.5～2% ZrO ₂

(f) 0.5～4% SnO ₂

(g) 0.05～5% at least a oxide that is selected from Ca, Mn, W;

(h) 0.5～8% MgO.

2,, it is characterized in that by weight percentage magnesian content is 0.5～3.0% in the catalyst according to the described oxide catalyst that is used for ethyl benzene dehydrogenation preparation of styrene of claim 1.