CN1218781C - Catalyst for preparing alkyl olefine arene by means of alkyl arene dehydrogenation - Google Patents

Abstract

The present invention relates to a catalyst for preparing alkyolefine aromatic hydrocarbon from alkyl aromatic hydrocarbon by dehydrogenation, which well mainly solves the problems of low selectively and low yield of the alkylolefine aromatic hydrocarbon existing in the prior art by the technical scheme of adding hafnium components to an iron-potassium-cerium-molybdenum catalytic system. The catalyst can be used for the industrial preparation of the alkylolefine aromatic hydrocarbon.

Description

The catalyst of dehydrogenating alkyl arene in preparing alkyl alkenyl arene

Technical field

The present invention relates to a kind of catalyst of dehydrogenating alkyl arene in preparing alkyl alkenyl arene.

Background technology

The manufacturing of industrial alkenyl arene realizes by alkyl aromatics dehydrogenation.Catalyst system therefor basic composition is major catalyst, co-catalyst and pore-foaming agent, reinforcing agent etc.The catalyst of patent report can be divided into two big classes.One class is the Fe-K series catalysts that contains Cr, as laid-open U.S. Patents US4467046, US4684619 and European patent EP 0195252A ₂Deng.Though such activity of such catalysts and stability are better, owing to more or less have the oxide of Cr in forming, thereby can cause certain environmental pollution in Preparation of catalysts, operation and the dead catalyst processing procedure, eliminated gradually.Another kind of is the Fe-K-Ce-Mo series that early eighties is succeeded in developing, as laid-open U.S. Patents US5190906, US4804799, world patent WO09839278A ₁Deng.This type of catalyst substitutes Cr with Ce, Mo, make catalyst keep on the basis of original stability, active also have by a relatively large margin raising than the former, adopted by countries in the world production of styrene producer, the subject matter that it exists is that selectivity of styrene is not high, by-product benzene content is more, brings difficulty for principal product output and later separation step.Therefore, seek a kind of high-selectivity catalyst of producing alkyl alkenyl arene, improve the yield of principal product alkyl alkenyl arene, be the very interested problems of people always.

Summary of the invention

Technical problem to be solved by this invention is to overcome in the past to exist the alkyl alkenyl arene selectivity low in the document, and the shortcoming that yield is low provides a kind of catalyst of new dehydrogenating alkyl arene in preparing alkyl alkenyl arene.This catalyst has the selectivity height of alkyl alkenyl arene, while alkyl alkenyl arene yield height, the characteristics that catalyst stability is good.

For solving the problems of the technologies described above, the technical solution used in the present invention is as follows: a kind of catalyst of dehydrogenating alkyl arene in preparing alkyl alkenyl arene comprises following active constituent by weight percentage: (a) 60～85% Fe ₂O ₃, (b) 5～25% K ₂O, (c) 4～8% Ce ₂O ₃, (d) 0.5～4% MoO ₃, (e) 0.01～3.0% HfO ₂, Fe wherein ₂O ₃By Fe ₂O ₃And Fe ₂O ₃H ₂O forms, by weight Fe ₂O ₃: Fe ₂O ₃H ₂O is 0.2～5: 1.

HfO by weight percentage in the technique scheme ₂The consumption preferable range be 0.5～2.0%, Fe by weight ₂O ₃: Fe ₂O ₃H ₂The O preferable range is 0.5～4: 1.

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

Fe ₂O ₃Be made up of iron oxide red and iron oxide yellow, potassium adds with the form of sylvite, and cerium adds with oxide, hydroxide or cerium salt form, and molybdenum adds with its salt or oxide form, and hafnium adds with the form of its oxide or salt.Also can add other metal oxide that is selected from alkali metal or alkaline-earth metal or IB～VIII family and IIIA～VIA family in addition in the catalyst activity component, its consumption is generally 0.01～10% of catalyst weight, and more preferably scope is 0.01～6%.

Also can comprise perforating agent in the catalyst of the present invention, its consumption is 1～4% of a catalyst weight, can choose from graphite, polystyrene microsphere, carboxymethyl cellulose etc.Also have binding agent in addition, generally use cement.

Method for preparing catalyst of the present invention:

After will evenly mixing by Fe, K, Ce, Mo, Hf and other co-catalyst component that need add, adhesive, the perforating agent of proportioning weighing, add proper amount of deionized water, make the paste of toughness, suitable extrusion, becoming diameter through extrusion, pelletizing is 3 millimeters, long 5～8 millimeters particle, in 80～120 ℃ of dryings 1～10 hour, 600～1000 ℃ of following roastings 1～8 hour, just can obtain finished catalyst then.

Dehydrogenation of the present invention under certain process conditions, can be applicable to fully by ethylbenzene, diethylbenzene, Alpha-Methyl ethylbenzene and make styrene, divinylbenzene and AMS.

The catalyst that makes as stated above carries out activity rating in the isotherm formula fixed bed, for the ethyl benzene dehydrogenation preparation of styrene activity rating, 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: with 100 milliliters, particle diameter is that 3 millimeters catalyst is 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 (water/ethylbenzene) (weight) 2.0.

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, air speed 6.0 hours ^-1Catalyst is accelerated the degradation data and is seen Table 2.

Conversion of ethylbenzene and selectivity of styrene calculate as follows:

The main side reaction of alkyl aromatics dehydrogenation such as ethylbenzene dehydrogenation is to generate toluene and benzene.Prove after deliberation: the generation of side reaction benzene need could take place in existing under the prerequisite of free state iron, therefore reduced the growing amount of free state iron, can reduce the growing amount of benzene, promptly reduced side reaction.Add the oxide of metal hafnium, can reduce the growing amount of free state iron, thereby the side reaction degree is reduced greatly, the selectivity and the yield of purpose product alkyl alkenyl arene have been improved, reduced side reaction, its selectivity generally can improve more than 2%, and yield also is greatly improved.Confirm that through test the Fe-K-Ce-Mo-Hf catalyst system and catalyzing has good catalytic stability, has obtained better technical effect in addition.

The invention will be further elaborated below by embodiment.

The specific embodiment

[embodiment 1]

230.14 iron oxide reds, 171.0 gram iron oxide yellows, 83.0 gram potash, 86.4 gram cerous nitrates, 10.3 gram molybdenum oxides, 15.0 gram hafnium oxide and 30.0 gram cement, 20.0 gram carboxymethyl celluloses were stirred in kneading machine 1 hour, add deionized water, mixed and stirred again 0.5 hour, take out extrusion, be extruded into the particle of 3 millimeters of diameters, 5～8 millimeters of length, put into baking oven, in 90 ℃ of bakings 2 hours, 120 ℃ were dried by the fire 2 hours, placed roaster then, made catalyst in 4 hours in 800 ℃ of roastings.Evaluation result sees Table 1.

Gained catalyst composed as follows:

Catalyst is formed (weight %)

Fe ₂O ₃ 76.80

K ₂O 11.31

Ce ₂O ₃ 6.84

MoO ₃ 2.05

HfO ₂ 3.00

[embodiment 2]

Remove HfO ₂Addition becomes outside 5.0 grams, and Preparation of Catalyst is with embodiment 1, gained catalyst composed as follows:

Catalyst is formed (weight %)

Fe ₂O ₃ 75.52

K ₂O 11.12

Ce ₂O ₃ 6.73

MoO ₃ 2.02

HfO ₂ 1.24

[embodiment 3]

Remove and change HfO ₂Addition is that Preparation of Catalyst is with embodiment 1 outside 2.5 grams.

Catalyst is formed (weight %)

Fe ₂O ₃ 78.77

K ₂O 11.61

Ce ₂O ₃ 7.01

MoO ₃ 2.10

HfO ₂ 0.50

[comparative example 1]

Remove and do not add HfO ₂, Preparation of Catalyst is with embodiment 3.

Catalyst is formed (weight %)

Fe ₂O ₃ 79.09

K ₂O 11.67

Ce ₂O ₃ 7.04

MoO ₃ 2.11

[embodiment 4]

With embodiment 1～3, the catalyst that comparative example 1 makes is respectively 1, and " check and rate on the stainless steel isotherm formula fixed bed reactors, reaction temperature is 620 ℃, and reaction pressure is a normal pressure, and the liquid air speed is 1.0 hours ^-1, water/ethylbenzene is 2.0 (weight), appraisal result sees Table 1.With the catalyst of embodiment 3, be 640 ℃ in reaction temperature in addition, water/ethylbenzene is 1.60 (weight), and the liquid air speed is 6.0 hours ^-1Check and rate under the condition, appraisal result sees Table 2.

The dehydrogenation product of each catalyst of table 1 distributes

Product distribution %The conversion of ethylbenzene selectivity of styrene

Catalyst

Benzene toluene ethylbenzene styrene % %

Embodiment 1 1.68 2.12 24.97 71.23 75.63 94.17

Embodiment 2 1.44 2.32 24.62 71.02 75.38 94.21

Embodiment 3 0.78 2.85 22.03 74.34 77.97 95.34

Comparative example 1 2.46 3.48 25.91 68.15 74.09 91.98

Table 2 embodiment 3 catalyst are accelerated the degradation data

The reaction temperature reaction time

(℃) 50 hours 100 hours 200 hours 300 hours 400 hours 500 hours

Conversion ratio % 66.14 65.08 63.68 61.98 61.21 60.77

Selectivity % 95.47 95.55 95.63 95.73 95.47 95.79

From the embodiment data, catalyst of the present invention in the Fe-K-Ce-Mo system, adds HfO ₂Metal oxide is as selectivity auxiliary agent, structural stabilizing agent, and made dehydrogenation selectivity of styrene is good, and the benzene by-product is few, and the styrene list is received high.Catalyst has the good stable performance simultaneously, is a kind of good high-selectivity catalyst.

Claims (3)

1, a kind of catalyst of dehydrogenating alkyl arene in preparing alkyl alkenyl arene comprises following active constituent by weight percentage: (a) 60～85% Fe ₂O ₃, (b) 5～25% K ₂O, (c) 4～8% Ce ₂O ₃, (d) 0.5～4% MoO ₃, (e) 0.01～3.0% HfO ₂, Fe wherein ₂O ₃By Fe ₂O ₃And Fe ₂O ₃H ₂O forms, by weight Fe ₂O ₃: Fe ₂O ₃H ₂O is 0.2～5: 1.

2,, it is characterized in that HfO by weight percentage according to the catalyst of the described dehydrogenating alkyl arene in preparing alkyl alkenyl arene of claim 1 ₂Consumption be 0.5～2.0%.

3,, it is characterized in that Fe by weight according to the catalyst of the described dehydrogenating alkyl arene in preparing alkyl alkenyl arene of claim 1 ₂O ₃: Fe ₂O ₃H ₂O is 0.5～4: 1.