CN102451702A - Acrylic acid catalyst prepared by acrolein oxidation and preparation method thereof - Google Patents

Abstract

The invention relates to an acrylic acid catalyst prepared by acrolein oxidation and a preparation method thereof, and mainly solves problems of low reaction yield and selectivity of a catalyst in a prior art. According to the invention, a carrier is at least one selected from SiO2, Al2O3 and TiO2; a catalyst contains an active component expressed by a following general formula: Mo12VaXbYcZdQeOx; X is at least one selected from W, Cr and Nb; Y is at least one selected from Cu, Fe, Ni, Co and Mn; Z is least one selected from Sb and Bi; Q is least one selected from Li, Na, K, Rb, Cs, Mg, Ca and Sr; an organic template like ethene diamine is added during a catalyst preparation process to guide catalyst pore structure. The above technical scheme well solves the problems and can be applied to industrial production of acrylic acid through acrolein oxidation.

Description

Acrolein oxidation system acrylic acid Catalysts and its preparation method

Technical field

The present invention relates to a kind of acrolein oxidation system acrylic acid Catalysts and its preparation method.

Background technology

It is the important chemical process that the selective oxidation of alkene prepares α, β unsaturated aldehyde and unsaturated acids, wherein uses a kind of active component to contain the catalyst of Mo, V by the production of unsaturated aldehyde system unsaturated carboxylic acid.The improvement of catalyst is mainly carried out from activity of such catalysts, selectivity and stable aspect, as in active constituent, adding transition metal to improve activity, increases the single of product and receives; Add rare earth element and improve redox ability, improve catalyst stability; Add elements such as Fe, Co, Ni to suppress the distillation of Mo, the stabilizing catalyst activity component improves the service life of catalyst etc.

Have a lot of patent reports for the methacrylaldehyde selective oxidation:

Wherein CN1183088C introduces a kind of method for preparing catalyst, and through selecting specific preparation raw material, acrolein conversion rate is the highest by 99.6%, and the acrylic acid selectivity is up to 96.0%, and the acrylic acid yield is up to 95.2%, and catalyst stability is good.

But we repeat said catalyst formulation of this patent and preparation method through overtesting, and the highest of acrolein conversion rate reaches 97.2%, and the acrylic acid selectivity is the highest has only 90.1%.

Summary of the invention

One of technical problem to be solved by this invention is that prior art acrylic acid catalyst reaction yield is not high, and the problem that selectivity is lower provides a kind of acrylic acid catalyst of new acrolein oxidation system that is used for.This catalyst is used for the methacrylaldehyde selective oxidation and produces the acrylic acid reaction, has the advantage that the catalyst propylene conversion is high, selectivity is good, the acrylic acid yield is high.Two of technical problem to be solved by this invention provides one of a kind of and technical solution problem used catalyst corresponding preparation method.

In order one of to solve the problems of the technologies described above, the technical scheme that the present invention adopts is following: a kind of acrolein oxidation system acrylic acid catalyst, and with SiO ₂, Al ₂O ₃Or TiO ₂In at least a be carrier, active constituent is by following general formula:

Mo ₁₂V _aX _bY _cZ _dQ _eO _x

X is selected from least a among W, Cr, the Nb in the formula;

Y is selected from least a among Cu, Fe, Ni, Co, the Mn;

Z is selected from least a among Sb, the Bi;

Q is be selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr at least a;

The span of a is 1.0～10.0;

The span of b is 0.2～7.0;

The span of c is 0.8～10.0;

The span of d is 0.2～6.0;

The span of e is 0.01～3.0;

X satisfies the required oxygen atom sum of other element valence;

The consumption of carrier is 10～40% of a catalyst weight in the catalyst;

Add at least a organic formwork agent in the catalyst preparation process, organic formwork agent is selected from least a in ethylenediamine, n-butylamine, triethanolamine, ethylene glycol, the glycerine.

In the technique scheme, described acrolein oxidation system acrylic acid catalyst, the span that it is characterized in that a is 1.0～10.0; The span of b is 0.2～7.0; The span of c is 0.8～10.0; The span of d is 0.2～6.0; The span of e is 0.01～3.0; Organic formwork agent is selected from least a in ethylenediamine, triethanolamine or the glycerine.

For solve the problems of the technologies described above two, the technical scheme that the present invention adopts is following: a kind of acrolein oxidation system acrylic acid Preparation of catalysts method, may further comprise the steps:

The ammonium molybdate that a) will prepare the catalyst aequum be dissolved in the water the solution I, then the carrier of aequum is added the solution I and gets the solution II;

B) with the ammonium metavanadate of aequum be dissolved in the water the solution III;

C) aequum is selected from the slaine of claim 1, be dissolved in the water the solution IV;

D) under agitation, solution III and solution IV are joined respectively in the solution II form catalyst pulp;

E) in solution II or catalyst pulp, add the organic formwork agent of aequum, organic formwork agent is selected from least a in ethylenediamine, triethanolamine or the glycerine;

F) slurry through spray shaping or the evaporation most of moisture after extrusion molding obtain catalyst precarsor, catalyst precarsor obtains the catalyst finished product through 380 ℃ of roastings.

In the technique scheme, described Preparation of catalysts method is characterized in that the addition of organic formwork agent accounts for 3～8% of catalyst weight in the catalyst preparation process.

The present invention is owing to added a kind of organic formwork agent in catalyst preparation process, this compound can influence the catalyst crystalline phases crystallization process, thereby reaches the reactivity worth that physical parameters such as catalyst assembled watch area, pore size distribution have improved catalyst.Catalyst of the present invention is used for the methacrylaldehyde selective oxidation and prepares acrylic acid, is that 270 ℃, reaction velocity are 1600 hours in reaction temperature ^-1Condition under, its acrolein conversion rate is up to 99.1%, the acrylic acid selectivity is up to 93.0%, product acrylic acid yield is up to 91.4%; Compare the sample that does not add, conversion ratio has improved 1.3%, and selectivity has improved 6%; Yield has improved 6.1%, has obtained better technical effect.

The present invention is directed to patent CN1183088C simultaneously and done certain prescription repeated in experiments, and, compare the sample that does not add adding organic template and the contrast of doing that does not add; Conversion ratio is the highest to have improved 1.3%; Selectivity has improved 1.4%, and yield has improved 2.5%, obtains better technical effect equally.

In the following embodiment that provides, be to the investigation appreciation condition of catalyst:

Reactor: fixed bed reactors, 25.4 millimeters of internal diameters, 750 millimeters of reactor length

Catalyst filling amount: 150 grams

Reaction temperature: 270 ℃

Reaction time: 4 hours

Feed oxygen alkene ratio: oxygen/propylene=2.0

Reaction velocity: 1600 hours ^-1

Product absorbs with 0 ℃ of diluted acid, uses the gas chromatographic analysis product.And the calculating Carbon balance, when Carbon balance is valid data during at (95～105) %.

Acrolein conversion rate, product yield and optionally be defined as:

Through embodiment the present invention is done further elaboration below.

The specific embodiment

[comparative example 1]

With 100 gram (NH ₄) ₆Mo ₇O ₂₄4H ₂O joins in the warm water of 70 ℃ of 100 grams, stirs and makes its whole dissolvings, adds the Ludox and the 12.7 gram (NH of 53.9 grams 40% (wt.) ₄) ₆H ₅[H ₂(WO ₄) ₆] process material A.

With 16.0 gram Cu (NO ₃) ₂3H ₂O adds in 70 ℃ of hot water of 20 grams, adds 6.95 gram Sb after the stirring and dissolving again ₂O ₃, 3.1 the gram Nb ₂O ₅, 0.48 the gram KNO ₃Process material B after the stirring and dissolving.

In 100 gram water, add 24.7 gram NH ₄VO ₃Form material C.

Material B and C are successively dripped in material A under stirring fast; Form catalyst pulp; And under 60 ℃, stirred aging 2 hours; Extrusion molding after 120 ℃ of oven dry removals of slurry most of moisture; Obtain the cylinder of

, high-temperature roasting obtains the catalyst finished product then, and sintering temperature is 380 ℃.

[comparative example 2]

With 123.6 gram (NH ₄) ₆Mo ₇O ₂₄4H ₂O, 4.6 gram MoO ₃, 38.4 the gram NH ₄VO ₃With 20.7 gram (NH ₄) ₆H ₅[H ₂(WO ₄) ₆] join 500 gram deionized waters, make it dissolving in heating and under stirring, this mixed-salt aqueous solution is A.

With 4.8 gram Sr (NO ₃) ₂With 33.5 gram Cu (NO ₃) ₂3H ₂O joins 50 gram deionized waters, makes it dissolving in heating and under stirring, and this mixed-salt aqueous solution is B.

AB solution is mixed, form the co-precipitation slurry, dry up into solid continuing under heating and the strong agitation evaporation, pulverize it then, form the powder C that passes through 60 eye mesh screens.

With fully mixing in 41 gram powder C and 300 orders, the 2.2 gram TeO adding blenders; Be shaped to the cylinder of

; High-temperature roasting obtains the catalyst finished product then, and sintering temperature is 380 ℃.

[embodiment 1]

With 100 gram (NH ₄) ₆Mo ₇O ₂₄4H ₂O joins in the warm water of 70 ℃ of 100 grams, stirs and makes its whole dissolvings, adds the Ludox and the 12.7 gram (NH of 53.9 grams 40% (wt.) ₄) ₆H ₅[H ₂(WO ₄) ₆] process material A.

With 16.0 gram Cu (NO ₃) ₂3H ₂O adds in 70 ℃ of hot water of 20 grams, adds 6.95 gram Sb after the stirring and dissolving again ₂O ₃, 3.1 the gram Nb ₂O ₅, 0.48 the gram KNO ₃Process material B after the stirring and dissolving.

In 100 gram water, add 24.7 gram NH ₄VO ₃Form material C.

Material B and C are successively dripped in material A under stirring fast; Form catalyst pulp; Adding 8.0 gram ethylenediamines also stirred under 60 ℃ aging 2 hours; Extrusion molding after 120 ℃ of oven dry removals of slurry most of moisture; Obtain the cylinder of

, high-temperature roasting obtains the catalyst finished product then, and sintering temperature is 380 ℃.

Embodiment 2,4,5,7 and 8 each steps by embodiment 1 make catalyst, just change the Preparation of Catalyst condition, add the kind and the consumption of organic formwork agent, and concrete outcome is listed in table 1, and under identical appreciation condition, reaction result is listed in table 2.

[embodiment 3]

With 123.6 gram (NH ₄) ₆Mo ₇O ₂₄4H ₂O, 4.6 gram MoO ₃, 38.4 the gram NH ₄VO ₃With 20.7 gram (NH ₄) ₆H ₅[H ₂(WO ₄) ₆] join 500 gram deionized waters, make it dissolving in heating and under stirring, this mixed-salt aqueous solution is A.

With 4.8 gram Sr (NO ₃) ₂With 33.5 gram Cu (NO ₃) ₂3H ₂O joins 50 gram deionized waters, makes it dissolving in heating and under stirring, and this mixed-salt aqueous solution is B.

AB solution is mixed, form the co-precipitation slurry, add 8.0 gram ethylenediamines again, dry up into solid continuing under heating and the strong agitation evaporation, pulverize it then, form the powder C that passes through 60 eye mesh screens.

With fully mixing in 41 gram powder C and 300 orders, the 2.2 gram TeO adding blenders; Be shaped to the cylinder of

; High-temperature roasting obtains the catalyst finished product then, and sintering temperature is 380 ℃.

Embodiment 6 and 9 each steps by embodiment 2 make catalyst, just change the kind that adds organic formwork agent, and concrete outcome is listed in table 1, and under identical appreciation condition, reaction result is listed in table 2.

Table 1 catalyst

Table 2 embodiment investigates the result

	Acrylic acid yield (%)	Acrylic acid selectivity (%)	Acrolein conversion rate (%)
				Comparative example 1	85.1	87.0	97.8
Comparative example 2	87.6	90.1	97.2
				Embodiment 1	91.4	92.5	98.8
Embodiment 2	90.5	92.2	98.2
				Embodiment 3	89.6	91.5	97.9
Embodiment 4	91.0	92.8	98.1
				Embodiment 5	90.9	93.0	97.8
Embodiment 6	90.1	91.5	98.5
				Embodiment 7	86.6	89.2	97.1
Embodiment 8	85.7	88.7	96.6
				Embodiment 9	88.3	90.6	97.5

Claims (5)

1. acrolein oxidation system acrylic acid catalyst is with SiO ₂, Al ₂O ₃Or TiO ₂In at least a be carrier, active constituent is by following general formula:

Mo ₁₂V _aX _bY _cZ _dQ _eO _x

X is selected from least a among W, Cr, the Nb in the formula;

Y is selected from least a among Cu, Fe, Ni, Co, the Mn;

Z is selected from least a among Sb, the Bi;

Q is be selected from Li, Na, K, Rb, Cs, Mg, Ca, Sr at least a;

The span of a is 1.0～10.0;

The span of b is 0.2～7.0;

The span of c is 0.8～10.0;

The span of d is 0.2～6.0;

The span of e is 0.01～3.0;

X satisfies the required oxygen atom sum of other element valence;

The consumption of carrier is 10～40% of a catalyst weight in the catalyst;

Add at least a organic formwork agent in the catalyst preparation process, organic formwork agent is selected from least a in ethylenediamine, n-butylamine, triethanolamine, ethylene glycol, the glycerine.

2. acrolein oxidation system acrylic acid catalyst according to claim 1, the span that it is characterized in that a is 1.0～10.0; The span of b is 0.2～7.0; The span of c is 0.8～10.0; The span of d is 0.2～6.0; The span of e is 0.01～3.0.

3. acrolein oxidation system acrylic acid catalyst according to claim 1 is characterized in that organic formwork agent is selected from least a in ethylenediamine, triethanolamine or the glycerine.

4. the described acrolein oxidation system acrylic acid of claim 1 Preparation of catalysts method, may further comprise the steps:

The ammonium molybdate that a) will prepare the catalyst aequum be dissolved in the water the solution I, then the carrier of aequum is added the solution I and gets the solution II;

B) with the ammonium metavanadate of aequum be dissolved in the water the solution III;

C) aequum is selected from the slaine of claim 1, be dissolved in the water the solution IV;

D) under agitation, solution III and solution IV are joined respectively in the solution II form catalyst pulp;

E) in solution II or catalyst pulp, add the organic formwork agent of aequum, organic formwork agent is selected from least a in ethylenediamine, triethanolamine or the glycerine;

F) slurry through spray shaping or the evaporation most of moisture after extrusion molding obtain catalyst precarsor, catalyst precarsor obtains the catalyst finished product through 380 ℃ of roastings.

5. according to claims 4 described Preparation of catalysts methods, it is characterized in that the addition of organic formwork agent accounts for 3～8% of catalyst weight in the catalyst preparation process.