CN100408165C - Catalyst for disproportionation of butene to ethylene and hexene - Google Patents

Abstract

The invention relates to a catalyst for the production of ethylene and hexene by disproportionation of butene, which mainly solves the difficulty in inhibiting the double bond isomerization reaction of 1-butene in the self-disproportionation reaction process of 1-butene in the prior art, and the low selectivity of ethylene and hexene in the disproportionation product The problem. The present invention uses at least one oxide selected from Al ₂ O ₃ , SiO ₂ or TiO ₂ as a carrier, and supports at least one oxide selected from Re or Co on the carrier to form a catalyst, preferably This problem is completely solved, and it can be used in the industrial production of butene disproportionation to produce ethylene and hexene.

Description

Catalyst for disproportionation of butene to ethylene and hexene

technical field

The invention relates to a catalyst for producing ethylene and hexene by disproportionation of butene.

Background technique

1-Hexene is an important additive for the synthesis of linear low-density polyethylene with high added value; butene is a by-product of steam cracking of naphtha and is generally consumed as liquefied petroleum gas. Through the self-disproportionation reaction of butene and the isomerization reaction of olefins, relatively excess butene with low added value can be converted into hexene and ethylene with high added value. The reaction formula is as follows:

The first step: butene isomerization reaction:

Second step: self-disproportionation reaction of 1-butene:

The third step: 3-hexene isomerization reaction

Among them, the control of the self-disproportionation reaction of 1-butene is the most critical, because in the process of self-disproportionation reaction of 1-butene, due to the action of acid or basic sites on the surface of the catalyst, it is easy to produce 1-butene double bond The isomerization reaction generates 2-butene, and 2-butene and 1-butene are cross-disproportionated to produce pentene and a certain amount of propylene with lower added value. The yield of hexene is very low due to the high speed of the double bond isomerization of 1-butene and the cross disproportionation of 2-butene and 1-butene.

WO02059600 reports the technology of automatic disproportionation of 1-butene to ethylene and hexene. The catalyst used in this technology is tungsten oxide supported on an inert carrier silicon oxide. At a temperature of 200°C to 350°C, 1-butene disproportionates itself on the catalyst to generate ethylene and 3-hexene. 3-Hexene is converted to 1-Hexene in a subsequent process by isomerization. The patent pointed out that by reducing the pressure of the reaction system and increasing the reaction space velocity, the contact time between the raw material and the disproportionation catalyst can be reduced, the double bond isomerization of 1-butene to 2-butene can be suppressed, and the selectivity of the reaction can be improved.

US6683019 reported the use of high-purity _SiO2 inert carrier to reduce the content of Al, Fe, Ca and other elements that are easy to form acid sites or basic sites on the carrier, reduce the occurrence of isomerization reactions, and improve the selectivity of ethylene and hexene.

However, the above-mentioned methods have limited inhibition of the double bond isomerization of 1-butene; The self-disproportionation reaction of 1-butene can greatly improve the selectivity of hexene and ethylene, and the key is to prepare an olefin disproportionation catalyst with high activity under low temperature conditions.

Contents of the invention

The technical problem to be solved by the present invention is the problem of high reaction temperature and low selectivity of ethylene and hexene in the prior art, and a new catalyst for producing ethylene and hexene by disproportionation of butene is provided. Using the catalyst for the disproportionation reaction of butene has the advantages of low reaction temperature and high selectivity of ethylene and hexene.

In order to solve the problems of the technologies described above, the technical scheme adopted in the present invention is as follows: a catalyst for producing ethylene and hexene by disproportionation of butene comprises the following components in weight percent:

(a) 80～99% is selected from _the support of at least one oxide in _Al2O3 , _SiO2 or _TiO2 ; And loaded on it

(b) 1 to 20% of at least one oxide selected from Re or Co.

In the above-mentioned technical scheme, the catalyst carrier is preferably Al ₂ O ₃ ; in weight percentage, the preferred solution is that the catalyst contains 1-20% Re oxide; in weight percentage, at least one of the oxides selected from Re or Co The preferred range of compound dosage is 6～12%.

The preparation method of the catalyst can be co-precipitation, ion exchange, impregnation, chemical adsorption, chemical deposition, physical mixing, and roasting at 350-700° C. for 0.5-20 hours under a certain atmosphere. The preferred scheme is that the transition metal compound aqueous solution is impregnated on the inert carrier, and after drying, it is calcined at 500-700°C for 4-8 hours in a dry air atmosphere. The catalyst needs to be formed by rolling balls, extruding into strips, and pressing into tablets.

The catalyst adopting the above-mentioned technical solution of the present invention can be used in the disproportionation reaction of olefins, and in the embodiment of the present invention, it is used to catalyze the self-disproportionation reaction of 1-butene to produce hexene and ethylene. The reaction condition is a fixed bed reactor, the reaction temperature is 0-200° C., the reaction pressure is 0-10 MPa, and the liquid phase space velocity is 0.1-10 hours ⁻¹ , butene-1 undergoes self-disproportionation reaction. The present invention still has high olefin disproportionation reaction activity at lower reaction temperature by using the above-mentioned catalyst, the 1-butene double bond isomerization reaction is suppressed, the selectivity of ethylene and hexene is greatly improved, and better technical effect.

Below by embodiment the present invention will be further elaborated.

Detailed ways

【Example 1】

Weigh 50 grams of roasted and dried γ-Al ₂ O ₃ (the specific surface area is 278 square meters per gram), put it into a dry glass beaker, and use a pipette to accurately measure 43 milliliters of rhenium with a concentration of 70 milligrams per 1 ml of perrhenic acid aqueous solution was placed in another beaker, and then 7 ml of deionized water was added and stirred evenly.

The above perrhenic acid solution was quickly poured into a beaker filled with γ-Al ₂ O ₃ , stirred evenly, left to stand for 4 hours, and dried at 120°C for 10 hours. Place the above-mentioned prepared sample in a tube furnace and feed dry air, the gas flow rate is controlled at 1000 mg/min, the temperature is raised to 550°C at a rate of 10°C/min and roasted, and kept for 8 hours, the obtained rhenium content is 6%. Re ₂ O ₇ /Al ₂ O ₃ catalyst samples.

[Example 2]

Weigh 50 grams of roasted and dried γ-Al ₂ O ₃ (the specific surface area is 278 square meters per gram), put it into a dry glass beaker, and use a pipette to accurately measure 50 milliliters of rhenium with a concentration of 70 milligrams per A milliliter of perrhenic acid aqueous solution was placed in another beaker. The above perrhenic acid solution was quickly poured into a beaker filled with γ-Al ₂ O ₃ , stirred evenly, left to stand for 4 hours, and dried at 120°C for 10 hours.

Accurately measure 7 milliliters of rhenium perrhenic acid aqueous solution with a concentration of milligrams per milliliter with a pipette and place it in a beaker, then add deionized water to make the solution volume 50 milliliters. The second impregnation was carried out as above and dried at 120°C for 10 hours. The catalyst sample was calcined according to the method described in Example 1 to prepare a catalyst sample with a rhenium content of 8% Re ₂ O ₇ /Al ₂ O ₃ .

[Embodiments 3-7]

Catalyst samples with rhenium contents of 10%, 12%, 14%, 16%, and 20% Re ₂ O ₇ /Al ₂ O ₃ were respectively prepared according to the method in Example 2.

Be 60 centimeters in length, be that the inner diameter of _1.8 centimeters is added the _volume is 80 cubic centimeters, _particle size is 10～20 _order glass ball fillers in the lower part of the reactor; 30 cubic centimeters of glass ball fillers with a particle size of 10 to 20 meshes are added to the top of the catalyst. The temperature of the reactor was raised to 550° C. under the condition of feeding 10 liters of nitrogen per hour, and kept at this temperature for 2 hours, and then dropped to a reaction temperature of 40° C.

The reactor stops feeding nitrogen, and feeds 99.5% 1-butene raw material from the upper end of the reactor, the raw material flow rate is 10 ml/hour, and the reaction system pressure is controlled at 3MPa by the regulating valve at the reactor outlet. The reaction products were analyzed online by gas chromatography after depressurization. The reaction results are shown in Table 1.

Table 1 Performance of self-disproportionation reaction of 1-butene on Re ₂ O ₇ /Al2O3 catalyst samples

[Embodiments 8-11]

Weigh 3.68, 5.52, 7.36, and 9.20 grams of ammonium molybdate samples (molecular formula: (NH ₄ ) ₆ Mo ₇ O ₂₄ 4H ₂ O) respectively, place them in 5 glass beakers, add 50 ml of deionized water to each, and stir Allow solid samples to dissolve completely. Weigh 5 parts of 50 grams each of γ-Al ₂ O ₃ (specific surface area is 278 square meters per gram) after roasting and drying, and put them into 5 dry glass beakers respectively;

The above-mentioned ammonium molybdate solutions with different concentrations were quickly poured into different beakers filled with γ-Al ₂ O ₃ , stirred evenly, left to stand for 4 hours, and dried at 120°C for 10 hours. The above-mentioned obtained samples were placed in a tube furnace and fed with dry air, the gas flow rate was controlled at 1000 ml/min, and the temperature was raised to 550 °C for roasting at a speed of 10 °C per minute, and kept for 8 hours, and the contents of the obtained molybdenum oxide were respectively 4%, 6%, 8%, 10% MoO ₃ /Al ₂ O ₃ catalyst samples.

In the lower part of the reactor with a length of 60 cm and an inner diameter of 1.8 cm, a glass ball filler with a volume of 80 cubic centimeters and a particle size of 10 to 20 mesh is added; 2 grams of MoO ₃ /Al ₂ O ₃ catalyst is added to the reactor, and the upper end Then add 30 cubic centimeters of filler glass balls with a particle size of 10 to 20 mesh. The temperature of the reactor was raised to 550° C. under the condition of feeding 10 liters/hour of nitrogen, and kept at this temperature for 2 hours, and then lowered to a reaction temperature of 120° C. to 150° C.

The reactor stops feeding nitrogen, and feeds 99.5% 1-butene raw material from the upper end of the reactor, the raw material flow rate is 10 ml/hour, and the reaction system pressure is controlled at 3MPa by the regulating valve at the reactor outlet. The reaction products were analyzed online by gas chromatography after depressurization. The reaction results are shown in Table 2.

Table 2 Self-disproportionation performance of 1-butene over MoO ₃ /Al ₂ O ₃ catalyst

Claims (4)

1. A catalyst for producing ethylene and hexene by disproportionation of butene comprises the following components in weight percent: (a) 80～99% is selected from _the support of at least one oxide in _Al2O3 , _SiO2 or _TiO2 ; And loaded on it (b) 1 to 20% of at least one oxide selected from Re or Co. 2. The catalyst for producing ethylene and hexene by disproportionation of butene according to claim 1, characterized in that the catalyst carrier is Al ₂ O ₃ . 3. according to the described butylene disproportionation of ethylene and the catalyzer of hexene of claim 1, it is characterized in that by weight percent, contain the oxide compound of 1～20% Re in the catalyzer. 4. The catalyst for producing ethylene and hexene by disproportionation of butene according to claim 1, characterized in that the amount of oxide selected from at least one of Re or Co is 6 to 12% in weight percent.