CN104646012A - Propylene selective oxidation catalyst and preparation method thereof - Google Patents

Abstract

The invention relates to a multi-metal oxide catalyst which contains following elements: molybdenum, bismuth, iron, nickel, cobalt and copper. The catalyst is represented as following general formula (I): Mo<a'>Bi<b'>Fe<c'>Ni<d'>Co<e'>Cu<f>Si<h>A<i>B<j>O<y>. The catalyst also contains a magnesium lanthanum aluminate oxide. The catalyst is used in a selective oxidation reaction of olefin. The active components, the molybdenum and the like, are not liable to loss due to sublimation and an active phase is not liable to cause phase transformation. The catalyst is high in reaction activity and selectivity and is long in service life.

Description

Propylene Selectivity oxidation catalyst and preparation method

Technical field

The present invention relates to a kind of catalyst of poly-metal deoxide, for catalyzing propone selective oxidation acrolein.

Background technology

Current industrial main employing propylene two-step oxidizing process prepares acrylic acid, and first propylene catalytic gas phase oxidation generates methacrylaldehyde, and methacrylaldehyde is reoxidised into acrylic acid.

Industrial propylene oxidation prepares the reaction unit mainly many reaction tubes of methacrylaldehyde, ensureing that catalyst is not sintered, under the prerequisite of long service life, improve selective and object product yield as far as possible, conservation, even if if feed stock conversion, methacrylaldehyde acrylic acid yield improve 0.1 ~ 0.5 percentage point, the amount of the product obtained increases with the level of hundreds of ~ thousands of tons of, and its economic benefit is also very considerable.

About propylene fraction oxidation acrolein, acrylic acid catalyst mainly molybdenum system multicomponent catalyst.Preparing the acrylic acid reaction of methacrylaldehyde due to Propylene Selectivity oxidation is strong exothermal reaction, so pass into the large steam of specific heat in course of reaction, effectively to remove reaction heat, but the easy losses under the washing away of the air-flows such as steam such as the active component molybdenum in catalyst.And under the high temperature conditions, in catalyst, part active component molybdenum loses from catalyst surface because of distillation.The loss of active component molybdenum causes reducing the activity of catalyst, selective, intensity and service life, and molybdenum is in the deposition in reaction system downstream, blocks the long-term operation of pipeline influential system.

In addition, the active component molybdenum in catalyst etc. i.e. enable maintenance is not run off, and before and after the reaction of molybdenum equal size, basic change is little, but is through long-term operation activity compatible and easily phase in version occurs.Key component in catalyst comprises Fe ₂(MoO ₄) ₃, α-Bi ₂(MoO ₄) ₃, CoMoO ₄and NiMoO ₄, wherein α-Bi ₂(MoO ₄) ₃be Active sites, play selective oxidation effect; Fe ₂(MoO ₄) ₃play redox facilitation; CoMoO ₄and NiMoO ₄play Stability Analysis of Structures effect.But, adopt the catalyst prepared of coprecipitation method due to component many, process is complicated, and catalyst stabilization differs, although initial activity is very high, inactivation is fast.What cause many components Mo-Bi-Co-Fe-O catalyst and Mo-V-O catalysqt deactivation and stability to decline is a lot of because have, comprising because of locally abnormal high temperature (focus) cause the sublimation of Mo component and irreversible crystalline phase change etc.These factors all can cause the change of specificity of catalyst, cause the reduction of catalyst activity and shorten service life of catalyst.By carrying out phenetic analysis to decaying catalyst, find Fe ₂(MoO ₄) ₃be reduced into FeMoO ₄, and α-Bi ₂(MoO ₄) ₃change γ-Bi into ₂moO ₆.

Solve the problem, the patent related to is many, such as, for suppressing the loss of molybdenum, CN1583261 discloses a kind of O composite metallic oxide catalyst for carrying out selective oxidation reaction in the gas phase containing the gas of unsaturated aldehyde and a kind of gas of molecule-containing keto, and its catalyst consists of: [Mo _av _bcu _cx _d] lY _m[Sb _ez ¹ _fz ² _g] _no _xwherein Mo is molybdenum, and V is vanadium, and Cu is copper, and Sb is antimony, and X is a kind of element being at least selected from tungsten and niobium, and Y is a kind of element being at least selected from titanium, antimony, Z ₁a kind of element of at least chosen from Fe and nickel, Z ₂it is a kind of element being at least selected from silicon, aluminium, alkali and alkaline earth metal ions, a, b, c, d, e, f, g and x represent the atomic ratio number of its element, when a=12 is benchmark, b is a number of 1 to 6, c is a number of 0.5 to 4, and d is a number of 0.05 to 4, and e is a number of 0.1 to 30, f is a number of 0 to 25, and g is a number of 0.01 to 20; X is by the number met needed for each metallic element combined oxidation state; Catalyst is made up of its each element oxide or composite oxides.

In order to improve the stability of catalyst, CN1130172 discloses a kind of acrylic acid catalyst, use ammonium metavanadate and copper nitrate respectively, and with Low Valent Vanadium oxide and/or at a low price Cu oxide part replace catalyst that raw material that ammonium metavanadate and/or copper nitrate make vanadium metal and copper obtains or except above-mentioned raw materials except, using sb oxide and/or low price tin-oxide obtain at a low price catalyst to demonstrate has a strengthened peak (vanadium-molybdenum reactive compound is peculiar) at d=4.00 and has the V of a remitted its fury at d=4.38_ ₂o ₅specific peak.Like this, catalyst obtained above has the catalytic activity of raising, and long-term performance can go out stability.Similar also has patent document 1: Japanese Unexamined Patent Publication 2002-233757 publication, patent document 2: Japanese Unexamined Patent Publication 8-299797 publication, patent document 3: Japanese Unexamined Patent Publication 9-194213 publication, patent document 4: Japanese Unexamined Patent Application Publication 2004-504288 publication; CN102066000A.

For improving activity, the selective and catalyst life of catalyst, CN200980112659.3 discloses a kind of coated catalysts comprising following component: (a) carrier, b () comprises molybdenum oxide or forms the ground floor of precursor compound of molybdenum oxide, (c) comprises the second layer of the poly-metal deoxide containing molybdenum and other metal of at least one.The molybdenum oxide of preferred ground floor is MoO ₃, the poly-metal deoxide of the second layer is the poly-metal deoxide that general formula I I represents: Mo ₁₂bi _acr _bx ¹ _cfe _dx ² _ex ³ _fo _y.This catalyst is the application type catalyst comprising carrier.Goal of the invention suppresses heterogeneously catalysed partial gas phase oxidation methacrylaldehyde to be acrylic acid coated catalysts inactivation, has the inactivation performance of improvement.This invention is not clearly recorded catalyst and is used for catalyzing propone oxidation acrolein, acrylic acid reactivity worth evaluating data, such as conversion ratio, selective, yield etc.CN87103192 discloses a kind of method of producing composite oxide catalysts, wherein comprise coherent element source compound to mix in Aquo System by the production method of the Mo-Bi composite oxide catalysts of following chemical formulation and form compound and this compound is heat-treated, adopt a kind of compound of the waltherite compound of (a) Bi and Na or (b) Bi, Na and X or (c) Bi and X as Bi source, in this compound at least containing required Na and/or X of part wherein: X represents Mg, Ca, Zn, Ce and/or Sm; Y represents K, Rb, Cs and/or Tl; Z represents B, P, As and/or W; A-K represents respective atomic ratio, and as a=12, b=0.5-7, c=0-10, d=0-10, c+d=1-10, e=0.05-3, f=0.01-1, g=0-1, h=0.04-0.4, i=0-3, j=0-48, k is a number meeting other element oxide state.Solve Bi can in composite oxide catalysts homodisperse problem.Containing α-Bi in catalyst ₂(MoO ₄) ₃, MoO ₃fe ₂(MoO ₄) ₃with β-CoMoO ₄, y-Bi ₂moO ₆and _γ-Bi ₂moO ₆.CN101690900A discloses a kind of preparation method preparing methacrylaldehyde and acrylic acid catalyst, and catalyst supports thing by active component and inert alumina carrier forms; The main component of active component, is selected from Mo, Bi, Co and/or Ni and Fe, also comprises the trace elements such as K, Na, Rb, Cs, Mg, Ca, Zn, B, P, W; Wherein the following statement formula of active component represents: Mo _abi _bco _cni _dfe _ex _fy _gz _ho _iin formula, X represents at least one of K, Na, Rb and Cs, and Y represents at least one be selected from B, P and W, and Z represents at least one be selected from Mg, Ca, Zn.The active component ratio be supported on carrier accounts for the 5-70% of overall catalyst weight; Active component is uneven distribution, CoMoO ₄, NiMoO ₄aluminate Deng divalent metal is positioned at the kernel of catalyst activity component; Fe ₂(MoO ₄) ₃and the MoO of free state ₃invest the skin of kernel; And the outermost layer of active component is bismuth molybdate, form the state of core-shell structure copolymer layer distributed.In active component, divalence molybdate is mainly beta phase structure, and α phase structure content in active component is very low or do not exist.Catalyst has high activity and high stability.CN1280036 mono-kind produces the catalyst of unsaturated aldehyde and unsaturated carboxylic acid, described production is by making at least one be selected from propylene, isobutene, the compound of the tert-butyl alcohol and methyl tertiary butyl ether(MTBE) and oxygen molecule or the gas containing oxygen molecule carry out vapour-phase oxidation and realize, it is characterized in that this catalyst is a kind of combined oxidation compositions, contain: (A) is containing molybdenum, bismuth and iron are as the composite oxides of key component, it itself is the known catalyst reacted for described vapor phase catalytic oxidation, (B) containing cerium and the zirconium composite oxides as key component.Catalyst has long catalytic life and makes running steady in a long-term become possibility.Wherein component (B) is the composite oxides represented with following general formula (2): Ce _pzr _qf _ro _y.The zirconia of high degree of dispersion inhibits the gathering of cerium oxide, to keep the latter to the promotion functions absorbing and discharge oxygen significantly in course of reaction, thus accelerates the oxidation reaction of isobutene, therefore improves catalytic activity.In addition, the irreversible activity that further suppress component (A) composite oxides caused because of over reduction in time reduces (i.e. the stability raising of composite oxides), thus catalytic life is extended.This catalytic activity that improve and the catalytic life extended inhibit reaction temperature to raise in time, thus reduce the distillation of molybdenum at hot spot.This catalyst is used for isobutylene oxidation.

CN102489309A discloses a kind of catalyst preparing for the production of methacrylaldehyde and renovation process.Catalyst is the composite oxides with following atomic ratio: Mo: Bi: Co: Ni: Fe=10-14: 1.2-2.0: 4.8-5.6: 2-3: 1-2; This catalyst has the pore size distribution of comparatively concentrating, moderate total pore volume, wherein the mesopore of about 5-10nm accounts for more than 70% of total pore size distribution, form short and thick pore passage structure, this feature gives catalyst stronger anti-carbon deposition ability, catalyst surface is easy-sintering not, can service life of extending catalyst.And by renovation process provided by the invention, decaying catalyst carries out 1-3 days calcination processing in an oxidizing atmosphere, and catalyst activity is suitable with fresh catalyst.CN87103192 produces the method for Mo-Bi-Na composite oxide catalysts product, the method comprises mixes coherent element source compound and form compound, then heat-treats, and using at least solid solution, the basic bismuth carbonate of the required Na of part is as Bi source compound.The activity of catalyst is able to great improvement by means of Bi and Na imports the catalyst of specific water-insoluble compound formation.

CN1109803 relates to multimetal oxide compositions, and they have two phase structure and comprise molybdenum, hydrogen, one or more element phosphor, arsenic, boron, germanium and silicon; And relate to described composition and prepared the purposes in methacrylic acid by catalytic gas phase oxidation, improve activity and selectivity.CN1109802 discloses a kind of multimetal oxide compositions, and they have two phase structure and comprise molybdenum, hydrogen, one or more element phosphor, arsenic, boron, germanium and silicon and copper, improves base acrylic acid activity and selectivity.CN1298861A adopts the composite oxides adding magnesium, aluminium and silicon.CN1321110A is then respectively using antimony oxide and antimony acetate as the antimony source of active composite metal oxide.Under solving high-load condition, catalytic mechanical intensity is good, active high problem.CN200410048021.7 discloses a kind of O composite metallic oxide catalyst, and catalyst is by 1. molybdenum, vanadium, copper main active component and 2. requisite at least by stable component and the 3. composite oxides that form of nickel, iron, silicon, aluminium, alkali metal, alkaline-earth metal of antimony and titanium.2. and be 3. wherein can composite oxides that within the scope of 120 DEG C to 900 DEG C prepared by roasting.This catalyst shows the permanent stability under high activity and good selectivity.CN1121441 discloses a kind of for by methacrylaldehyde or carry out oxidation reaction containing the gas of acrolein gas and a kind of molecule-containing keto in vapour phase and produce acrylic acid catalyst, this catalyst comprises (A) a kind of composite oxides, there is molybdenum and vanadium as base stock, and be suitable for by vapor phase catalytic oxidation methacrylaldehyde to produce acrylic acid, (B) solid peracid, its acid strength (Ho) is not more than-11.93 (Ho≤-11.93).This invention adopts molybdenum vanadium type composite oxides to combine with the solid acid that a kind of acid strength is no more than-11.93, improves the low temperature high activity of catalyst.CN200510059468.9 discloses a kind of acrylic acid catalyst for producing, it is characterized in that, the oxide of the metallic element composition represented at following formula M oaVbWcCudOx (1) and/or composite oxides are must in the acrylic acid catalyst for producing of catalyst component, need to control the face side that tungsten is this catalyst partially, and/or copper is the core side of this catalyst partially, to improve catalyst activity.Tungsten is the face side of this catalyst partially, and/or copper is that the core side of this catalyst is difficult to accurately control partially.CN102039143A discloses the preparation method that a kind of acrolein oxidation prepares acrylic acid catalyst, a) preparation method of composite oxide coating: be dispersed in water/organic phase mixed system by the water-soluble metal salt containing Mo, V, W, Cu, Sb composition in 30-100 DEG C; Organic solvent and water weight ratio is kept to be 5 ~ 50%; Reaction generates composite oxides presoma slurries; Catalyst activity component is obtained again through distillation, oven dry, roasting; B) the main component of above-mentioned active component, be selected from Mo, V, Cu, W, Sb wherein one or more; Wherein active component following formula represents: Mo _av _bcu _cw _dsb _eo _fthis catalyst adopts the mixed system preparation of water and lower alcohol, and catalyst has higher specific area and special microstructure, has comparatively high-ratio surface and difficult drop-off, and bearing capacity can reach 50% and more than, solve shorter problem in application type catalyst service life.

CN1647854 discloses a kind of catalyst of selectively oxidizing methyl acrylic aldehyde to synthesize methyl propenoic acid, and the composition general formula of this catalyst is: x (Mo ₁₂p _ak _bsb _ccu _das _ea _fd _gq _ho _imo _j)/yZ, Z is carrier dilution thermal conducting agent; Mo, P, K, Sb, Cu and As are respectively molybdenum, phosphorus, potassium, antimony, copper and arsenic; A represents at least one element in tungsten W, vanadium V, niobium Nb, iron Fe and plumbous Pb; D represents at least one element in boron, gallium Ga, indium In, germanium Ge and silicon Si; Q represents at least one element in rubidium Rb, caesium Cs and thallium Tl, and this invention improves the activity and selectivity of catalyst on the one hand by adding Sb, Cu and As; On the other hand by adding MoO ₃improve the heat endurance of catalyst, heat conductivility and mechanical strength with carrier heat conduction diluent, effectively inhibit activities component heteropolyacid salt decomposition and reduce beds hot(test)-spot temperature, avoid the loss of Mo and As, extending catalyst service life.

CN1109800 discloses a kind of polymetal oxide materials: in formula, A is Mo ₁₂v _ax _b ¹x _c ²x _d ³x _e ⁴x _f ⁵x _g ⁶o _x(coexisting phase), its part B comprises the crystallite (giving the firsthand information about X-ray diffraction fingerprint in round parentheses) of the X-ray diffraction pattern with the following copper molybdate of at least one: Cu ₃(MoO ₄) ₂(OH) ₂(lindgernite, the card index 36-405 of JCPDS-ICDD index (1991)), Cu ₄mo ₆o ₂₀(people such as A.Moini, Inorg.Chem.25(21) (1986), 3782-3785), Cu ₄mo ₅o ₁₇(the card index 39-181 of JCPDS-ICDD index (1991)), etc.CN1462211 relates to a kind of method preparing multiple-phase multi-metal oxide materials containing Mo, V, Cu and other optional element.According to this invention, at least one phase is pre-formed independently, and is dispersed in the precursor material of the plastically deformable of another phase.Then this mixture carries out drying and calcining.Polymetal oxide materials is suitable as at catalytic gas phase oxidation organic compound, particularly acrolein oxidation is being become the active material of catalyst used in acrylic acid.[A] p [B] q [C] r (I), the phase A in multimetal oxide compositions, B and C can be unbodied and/or crystallizations.Phase B is advantageously made up of the crystallite of oxometallate, or comprises there is X-ray diffraction pattern and and then the crystal structure class α-CuMo of oxometallate crystallite copper molybdate of crystal structure types of the following copper molybdate of at least one ₄[the registration card 22-242 of JCPDS-ICDD card index, (1991)], Cu ₆mo ₅o ₁₈[the registration card 40-865 of JCPCS-ICDD card index, (1991)], Cu _4-xmo ₃o ₁₂, wherein x=0-0.25 [registration card 24-56 and 26-547 of JCPCS-ICDD card index, (1991)], etc.This catalyst is selective in order to improve.

CN1295499 discloses polymetal oxide materials [A] p [B] q [C] r (I) of a kind of formula (I), with containing molybdenum, vanadium, copper and antimony and one or more other metals specific and the polymetal oxide materials with multicomponent structure prepares acrylic acid catalyst as with the gas phase catalytic oxidation reaction of methacrylaldehyde.In formula, A is Mo ₁₂v _ax ¹bX ² _cx ³ _dx ⁴ _ex ⁵ _fx ⁶ _go _x, B is X ¹ ₇cu _hh _io _y, C is X ₁ ⁸sb _jh _ko _z, X ₁for W, Nb, Ta, Cr and/or Ce.Co-catalyst phase B is made up of the crystallite of these copper molybdate or contains such copper molybdate crystallite: α-CuMoO ₄[the reference diffraction pattern in the index card 22-242 of JCPDS-ICDD retrieval 1991], Cu ₆mo ₅o ₁₈[the reference diffraction pattern in the index card 40-865 of JCPDS-ICDD retrieval 1991], Cu _4-xmo ₃o ₁₂wherein, x is 0-0.25 [the reference diffraction pattern in index card 24-56 and 26-547 of JCPDS-ICDD retrieval 1991], etc.Region C can have metaantimmonic acid copper Cu ₉sb ₄o ₁₉the crystallite of structure or Cu ₄sbO _4.5the crystallite of structure.CN1093950 discloses the composition of one kind of multiple metal oxides, comprise Mo, V, W, Cu, the Ni of the oxidised form as basis, its prerequisite there is following ratio between each elemental composition: Mo:V=12:1 to 2:1, Mo:W=60:1 to 3:1, Mo:Cu=24:1 to 2:1, Cu:Ni=5:1 to 1:3.X ₁one or more alkali metal; X ₂one or more alkaline-earth metal; X ₃cr, Mn, Ce and/or Nb; X ₄sb and/or Bi; X ₅si, Al, Ti and/or Zr.CN1387945 relates to the oxo metallide of the HT copper molybdate structure type being selected from the element in element W, V, Nb and Ta containing Cu, Mo and at least one, its preparation method, and they also contain the application had in the composite metal oxide material of heterogeneous structure of one or more elements in elemental tungsten, niobium, tantalum, chromium and cerium in preparation containing molybdenum, vanadium, copper.The poly-metal deoxide that CN1394812 uses in the catalyst of the catalytic vapor phase oxidation reaction for organic compound, said poly-metal deoxide contains at least one in Mo, V and element W, Nb, Ti, Zr, Hf, Ta, Cr, Si and Ge, and has special Three-dimensional atom arrangement.CN1500770 contains molybdenum, vanadium, the composite metal oxide material that have heterogeneous structure of copper also containing one or more elements in elemental tungsten, niobium, tantalum, chromium and cerium, they are by the application in catalytic gas phase oxidation of acrolein acrylic acid, and are selected from the oxo metallide of the HT copper molybdate structure type of the element in element W, V, Nb and Ta containing Cu, Mo and at least one.

In addition, under the high temperature conditions, in catalyst, part active component molybdenum loses from catalyst surface because of distillation.The mixed airflows such as methacrylaldehyde, air (oxygen), nitrogen and steam wash away the loss of active component that also can make in catalyst.For suppressing the loss of molybdenum distillation to cause active decay, CN1121504, by mixing copper component and having the zirconium of specified particle diameter and specific area and/or titanium and/or cerium, can suppress dissipation effect and the over reduction of molybdenum composition.Catalyst comprises by following formula (I) MO _av _bw _ccu _dx _ey _f(I) oxide of the metallic element composition represented or composite oxides.CN1445020 adds the effect that a small amount of tellurium plays stable free molybdenum trioxide and copper molybdate crystal structure, and sublimation and the over reduction of molybdenum suppress to some extent; CN1583261 is with molybdenum, vanadium, copper, tungsten and/or niobium for key component, and the composite oxides formed with other element or its hopcalite form the loss that catalyst suppresses molybdenum.

Therefore, need to provide Propylene Selectivity to be oxidized and prepare methacrylaldehyde, acrylic acid catalyst, catalyst activity component molybdenum etc. not easily runs off, and not easily there is phase in version in active phase, in acrolein oxidation process, temperature of reactor distribution is more reasonable, and improves the selective and yield of object product as far as possible, to obtain larger economic benefit., can react under low temperature, high-load condition.

Summary of the invention

The object of this invention is to provide the oxidation of a kind of Propylene Selectivity and produce methacrylaldehyde, acrylic acid multi-metal-oxide catalyst and preparation method thereof.

The present invention relates to a kind of propylene oxidation catalyst, catalyst contains molybdenum, bismuth, iron, nickel, cobalt and copper, mainly forms by formula M o _{a '}bi _{b '}fe _{c '}ni _{d '}co _{e '}cu _fsi _ha _ib _jo _y(I) represent, wherein: Mo is molybdenum, Bi is bismuth, and Fe is iron, and Ni is nickel, and Co is cobalt, and Cu is copper, and Si is silicon, and silicon is the carrier added in catalyst, and A is at least one element be selected from caesium, calcium or barium; B is at least one element be selected from titanium, zinc, potassium, lanthanum; O is oxygen; A ', b ', c ', d ', e ', f, h, i, j represent each Elements Atom ratio respectively, and wherein a ' is a number of 12-14, and b ' is a number of 1-6, preferred 1.2-5; C ' is a number of 0.2-5, preferred 0.5-3.5; D ' is a number of 1-6, preferred 1.5-4; E ' is a number of 0.5-6, and preferred 1.5-4.5, f are numbers of 0.2-4, and h is a number of 0.1-30, and i, j are numbers of 0.05-2.5, and y is the numerical value determined by the oxygen of each oxide.Catalyst is also containing lanthanum-magnesium aluminate oxide (LaMgAl ₁₁o ₁₉), containing molybdenum, (I) of bismuth and lanthanum-magnesium aluminate oxide by after 90 ~ 98% and 0.5 ~ 10% mass percent mixing through mediating, obtain finished catalyst after shaping, dry, roasting.

Lanthanum-magnesium aluminate oxide of the present invention coprecipitation preparation conveniently.Prepare as adopted following method: by magnesium nitrate, lanthanum nitrate and aluminium hydroxide according to LaMgAl ₁₁o ₁₉stoichiometric proportion mix, add deionized water and stir, then spraying dry, gained powder after 160 DEG C of dryings through 1000 ~ 1500 DEG C of roastings 3 ~ 12 hours, then by pulverize or the method such as ball milling obtains the lanthanum-magnesium aluminate LaMgAl of particle diameter below 20 μm ₁₁o ₁₉.

More preferably, containing (I) 92 ~ 97% in catalyst, also has lanthanum-magnesium aluminate oxide 2 ~ 8%.

Preferably add active component lanthanum in the catalyst activity component that the present invention (I) represents, lanthanum and bismuth, cobalt, copper can form stable crystal phase structure, as BiLa, BiLa ₂, Co ₃la ₂, Cu ₂la etc., the good dispersion of molybdenum, thus suppress part active component molybdenum to lose from catalyst surface because of distillation, active component molybdenum etc. not easily runs off, before and after catalyst reaction, active component molybdenum content is substantially constant, delays active deterioration rate, catalyst activity and good stability.Lanthanum and molybdenum, cobalt ratio are suitable, and in general formula (I), B is lanthanum, and i is a number of 0.1 ~ 1.5, and j is a number of 0.1 ~ 3, too much lanthanum add membership and molybdenum competed by bismuth, cobalt and iron, affect catalyst activity.Catalyst mainly forms and is represented by general formula (II): Mo _{a '}bi _{b '}fe _{c '}ni _{d '}co _{e '}cu _fsi _ha _ila _jo _y(II).

Multi-metal-oxide catalyst of the present invention (I) adopts common preparation method, as following step can be adopted to prepare, by A in the compound containing Mo, Bi, Fe, Co, Ni, Cu and general formula (I) _ib _jthe each elemental constituent compound related to dissolve and mix, form slurries after carrying out co-precipitation, in slurry production process, add one or more in silica, aluminium oxide or carborundum, dry, shaping, roasting obtains catalyst (I).

The preparation method of catalyst of the present invention, comprise with coprecipitation Kaolinite Preparation of Catalyst (I), lanthanum-magnesium aluminate oxide, by catalyst (I), lanthanum-magnesium aluminate oxide by after 90 ~ 98% and 0.5 ~ 10% mass percent mixing through mediating, obtain finished catalyst after shaping, dry, roasting.

Under Oxygen Condition, catalyst under the high temperature conditions molybdenum isoreactivity component not only easily runs off, and activity compatible easily phase in version occurs, and activity phase in version occurs mutually and causes active selectable obviously to decline.As active phase CuMoO ₄change MoO into ₃, CoMoO ₄be converted into Co ₃o ₄, Fe ₂(MoO ₄) ₃be transformed into FeMoO ₄, α-Bi ₂(MoO ₄) ₃change γ-Bi into ₂moO ₆deng.

Active component molybdenum in catalyst etc. i.e. enable maintenance is not run off, and before and after the reaction of molybdenum equal size, basic change is little, but is through long-term operation activity compatible and easily phase in version occurs.Lanthanum-magnesium aluminate oxide adds in catalyst by the present invention, makes active phase more stable, not easily phase in version occurs thus improves catalyst activity and selectivity, enabling catalyst long-term operation.

Catalyst of the present invention (I) and finished catalyst all need roasting 3 ~ 10h at 400 ~ 580 DEG C, and compare the catalyst of not roasting respectively, repeatedly roasting can improve activity and the stability of catalyst.Can be open roasting also can be enclosed roasting, calcination atmosphere can be the inert gases such as helium, nitrogen, argon gas.

The compound of each component of catalyst of the present invention can use the nitrate, ammonium salt, sulfate, oxide, hydroxide, chloride, acetate etc. of each element, as lanthanum nitrate, magnesium nitrate, calcium chloride, calcium chloride, brium carbonate, barium nitrate, potassium nitrate, zinc nitrate, titanium dioxide, calcium hydroxide, strontium nitrate, ferric nitrate, iron oxide, cobalt nitrate, cobalt oxide, bismuth nitrate, ammonium molybdate etc.

After catalyst slurry of the present invention is dried, the forming methods such as extrusion molding, granulating and forming, compression molding are usually preferably adopted to be processed into spherical, hollow spheres, ellipticity, cylindric, hollow circuit cylinder etc., preferably hollow circuit cylinder or spherical.

The present invention, in order to improve intensity, the efflorescence degree of catalyst, can to add in glass fibre, graphite, pottery or various whisker one or more in the above-mentioned catalyst (I).

Evaluating catalyst performance index definition is as follows:

Detailed description of the invention

With specific embodiment, multi-metal-oxide catalyst and preparation method thereof is described below, and this catalyst prepares the catalytic performance of methacrylaldehyde (ACR), acrylic acid (AA) in Propylene Selectivity oxidation, but scope of the present invention is not limited to these embodiments.Following examples adopt propylene be propylene content >=99.6%(volume fraction) high concentration propylene.The analytical method of product composition adopts this area universal method.

Embodiment 1

Under agitation, get 236.5 grams of ammonium molybdates and be dissolved in (water temperature more than 65 DEG C) in 1000ml pure water, obtain slurries (1), then get 89.1 grams of cobalt nitrates, 64 grams of nickel nitrates, 115.9 grams of ferric nitrates, 22.3 grams of copper nitrates, 34.2 grams of lanthanum nitrates are dissolved in (water temperature more than 65 DEG C) in 500ml pure water, fully be uniformly mixed, obtain slurries (2).Get 162.5 grams of bismuth nitrates again, be dissolved under agitation in dust technology, obtain slurries (3).Then, slurries (1) mix with slurries (2), obtain slurries (4), are then added in slurries (4) by slurries (3), then add 3.8 grams of titanium dioxide and 4 grams of graphite, obtain active component slurries (a).Active component slurries (a) and 7.4 grams of silicon dioxide powders are carried out coprecipitation reaction, through heat drying, with 150 DEG C of heat treatments 3 hours in nitrogen, then 500 DEG C of roastings 4 hours, the fine powder of less than 40 μm is obtained through pulverizing, grinding, sieve process, namely be catalyst (I) powder, mainly consist of:

Mo ₁₃Bi _3.3Fe _2.8Ni _2.1Co _3.0Cu _0.93Si _1.2La _1.0Ti _0.46O _y（Ⅰ）

By magnesium nitrate, lanthanum nitrate and aluminium hydroxide according to LaMgAl ₁₁o ₁₉stoichiometric proportion mix, add deionized water and stir, then spraying dry, gained powder through 1100 DEG C of roastings 10 hours, then obtains the lanthanum-magnesium aluminate LaMgAl of particle diameter below 20 μm by the method such as ball milling after 160 DEG C of dryings ₁₁o ₁₉.

Get catalyst (I) 93 part, lanthanum-magnesium aluminate oxide 7 parts, adds deionized water and mediates in kneader, and extruded is the hollow columnar particle of φ 4.5 × 5mm, and dry under 120 DEG C of conditions, at 450 DEG C, roasting obtains catalyst 1 in 6.5 hours.

Embodiment 2

With the preparation process of embodiment 1 catalyst 1 and most of raw material identical, within 4 hours, namely obtain catalyst (I) through 500 DEG C of roastings, mainly consist of: Mo ₁₃bi _4.2fe ₄ni ₃co _3.6cu _0.3si _2.2ba _0.3k _0.4o _y(I).Get catalyst (I) 90 part, lanthanum-magnesium aluminate oxide 10 parts, adds deionized water and mediates in kneader, and extruded is the hollow columnar particle of φ 4.5 × 5mm, and dry under 120 DEG C of conditions, at 550 DEG C, roasting obtains catalyst 2 in 4 hours.

Embodiment 3

With the preparation process of embodiment 1 catalyst 1 and primary raw material identical, within 5 hours, namely obtain catalyst (I) through 450 DEG C of roastings.Mainly consist of: Mo ₁₄bi ₅fe _2.5ni ₄co ₄cu ₂si _3.5k _0.2la _1.8o _y(I).Get catalyst (I) 95 part, lanthanum-magnesium aluminate oxide 5 parts, adds deionized water and mediates in kneader, and extruded is the hollow columnar particle of φ 4.5 × 5mm, and dry under 120 DEG C of conditions, at 550 DEG C, roasting obtains catalyst 3 in 4 hours.

Embodiment 4

With the preparation process of embodiment 1 catalyst 1 and primary raw material identical, within 7 hours, namely obtain catalyst (I) through 400 DEG C of roastings.Mainly consist of: Mo ₁₄bi ₆fe ₅ni ₆co _5.8cu _3.8si _1.8cs _0.2la _3.3o _y(I).Get catalyst (I) 97 part, lanthanum-magnesium aluminate oxide 3 parts, adds deionized water and mediates in kneader, and extruded is the hollow columnar particle of φ 4.5 × 5mm, and dry under 120 DEG C of conditions, at 500 DEG C, roasting obtains catalyst 4 in 5 hours.

Comparative example 1

Main composition and ratio according to embodiment 1 prepares comparative catalyst 1, but lanthanum-magnesium aluminate is not add catalyst with the form of solid solution, oxide, but with coprecipitation method Kaolinite Preparation of Catalyst, reaction condition is with the appreciation condition of catalyst 1.Comparative catalyst 1 mainly consists of:

Mo ₁₃Bi _3.3Fe _2.8Ni _2.1Co _3.0Cu _0.93Si _1.2La _1.3Ti _0.46Mg _0.3Al _3.3O _y

Oxidation reaction

Fixed bed single tube reactor internal diameter 25mm, inside establishes thermocouple, loads the above-mentioned catalyst of 50ml or comparative example catalyst, salt bath heating, salt temperature 310 DEG C along propylene feed orienting response device bed.From above-mentioned reaction tube porch with air speed 1200h ^-1import the mist of propylene 9 volume %, air 72 volume %, steam 19 volume %.Reaction result as shown in Table 1 and Table 2.React 24 hours and 2000 hours, load beds hot localised points temperature of the present invention not higher than 361 DEG C, catalyst activity component molybdenum etc. not easily runs off, and phase in version not easily occurs active phase, and catalyst activity component structure is stablized.In acrolein oxidation process, reaction bed temperature distribution is more reasonable, and methacrylaldehyde (ACR) and acrylic acid (AA) total recovery more than 91.0%, catalyst has good water repelling property, catalyst performance stabilised, meets the steady running of device long period.Comparative example catalyst choice is poor, and methacrylaldehyde, acrylic acid yield are low.

Table 1 reacts 24 hours post-evaluation results

Table 2 reacts 2000 hours post-evaluation results

Claims (10)

1. a catalyst for Propylene Selectivity oxidation, is characterized in that catalyst contains molybdenum, bismuth, iron, nickel, cobalt and copper, mainly forms by formula M o _{a '}bi _{b '}fe _{c '}ni _{d '}co _{e '}cu _fsi _ha _ib _jo _y(I) represent, wherein silicon is carrier, and A is at least one element be selected from caesium, calcium or barium; B is selected from least one element in titanium, zinc, potassium, lanthanum; O is oxygen; A ', b ', c ', d ', e ', f, g, h, i, j represent each Elements Atom ratio respectively, wherein a ' is a number of 12-14, b ' is a number of 1-6, c ' is a number of 0.2-5, and d ' is a number of 1-6, and e ' is a number of 0.5-6, f is a number of 0.2-4, h is a number of 0.1-30, and i, j are numbers of 0.05-2.5, and y is the numerical value determined by the oxygen of each oxide; Catalyst, also containing lanthanum-magnesium aluminate oxide, obtains finished catalyst by after 90 ~ 98% and 0.5 ~ 10% mass percent mixing containing molybdenum, (I) of bismuth and lanthanum-magnesium aluminate oxide after kneading, shaping, dry, roasting.

2. catalyst according to claim 1, catalyst contains (I) 92 ~ 97%, also has lanthanum-magnesium aluminate oxide 2 ~ 8%.

3. catalyst according to claim 1, is characterized in that in general formula (I), b ' is a number of 1.2-5.

4. catalyst according to claim 1, is characterized in that in general formula (I), c ' is a number of 0.5-3.5.

5. catalyst according to claim 1, is characterized in that in general formula (I), d ' is a number of 1.5-4.

6. catalyst according to claim 1, is characterized in that in general formula (I), e ' is a number of 1.5-4.5.

7. catalyst according to claim 1, it is characterized in that in general formula (I), B is lanthanum, i is a number of 0.1 ~ 1.5, and j is a number of 0.1 ~ 3, and main composition is represented by general formula (II):

Mo _a′Bi _b′Fe _c′Ni _d′Co _e′Cu _fSi _hA _iLa _jO _y（Ⅱ）。

8. catalyst according to any one of claim 1 ~ 7, is characterized in that the preparation of catalyst (I) comprises the steps: A in the compound containing Mo, Bi, Fe, Co, Ni, Cu and general formula (I) _ib _jthe each elemental constituent compound related to dissolve and mix, form slurries after carrying out co-precipitation, in slurry production process, add one or more in silica, aluminium oxide or carborundum etc., dry, shaping, roasting obtains catalyst (I).

9. the preparation method of catalyst according to claim 1, it is characterized in that comprising with coprecipitation Kaolinite Preparation of Catalyst (I), lanthanum-magnesium aluminate oxide, by catalyst (I), lanthanum-magnesium aluminate oxide by after 86 ~ 96% and 0.1 ~ 5% mass percent mixing through mediating, obtain finished catalyst after shaping, dry, roasting.

10. method according to claim 9, is characterized in that catalyst (I) and finished catalyst all need roasting 3 ~ 10h at 400 ~ 580 DEG C.