CA1083165A - Preparation of maleic anhydride from four-carbon hydrocarbons - Google Patents

Abstract

PREPARATION OF MALEIC ANHYDRIDE
FROM FOUR-CARBON HYDROCARBONS

ABSTRACT OF THE DISCLOSURE

Maleic anhydride is produced by the oxidation of n-butane, n-butenes, 1,3-butadiene with molecular oxygen in the vapor phase in the presence of catalysts containing molybdenum, phosphorus, oxygen and the following components delineated in Groups I to IV: (I) bismuth, copper and a halogen selected from the group consisting of chlorine, bromine or iodine; or (II) arsenic and at least one element selected from the group consisting of Sn, rare earth metal, Zr, Rh, Mn, Re, Ru, Cu, Pb, Zn, Ti, Cr, Nb, Al, Ga and alkaline earth metal; or (III) at least one element selected from the group consisting of As, Rb, Pd, Cd, Cs, Tl and In;
or (IV) rubidium, and at least one element selected from the group consisting of Sn, rare earth element, Ni, Zr, Ba, Fe, Rh, Mn, Re, Ru, Co and Cu.

Description

BACICGR( ~D O_ TIIE ~~IVE~ITION

Belgian Patent No. 828,074 ~:eaches the use of a catalyst containing phosphorus, molybdenum, bismuth, copper, at least one of Fe, Ni, Co and K, ancl optionally, Li, Na, Rb, Cs, Be, Mg, Ca, Sr, or Ba in the preparation oE maleic anhydride ~rom butene-l, butene~2, butadiene, pentane, pentadiene, cyclopentadiene and benzene. Comparative Example 4, at pages 20 and 21 of -this patent exemplifies that use of a catalyst having the formula Pl 00~Il2Bio.36CU0.5439.6 in the oxidation of butene-l gave a 27.9~ yield of maleic anhydride, based on the amount of butene-l fed.

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6 1 ) (Ll~63) ( l~96L~ ) 3~ ~ 5 (4~65) ~rench Patent No. 1,601,955 teaches use of a catalyst having the composition AO3-B2O5-M2O5-NX0-R2O
wherein A is Cr, Mo, W or U; B is V or Nb; M is P, Asg Sb or Bi, N is Cu, Ag, Fe, Co or Ni; R is Li, Na, K, Cs or Rb.
Preferred composition is 15-55 atomic ~ A, 30-70% B, 0-15%
M, 0.1-20% N, and 0-15% R.
The present invention is a result of a search fo-r more efficient catalysts for use in the oxidation of n-butane, n-butenes and 1,3-butadiene.
The catalysts employed in the present invention are unexpectedly advantageous in the production of maleic anhydride from n-butane, n-butenes and 1,3-butadiene.
Especially desirable yields are obtained from 1,3-butadiene or n-butenes usin~ catalysts of the invention.

SUMMARY OF THE INVENTION
. It has now been discovered according to the pre-sent invention in the process for the production of maleic anhydride by the oxidation of n-butane, n-butenes, 1,3-butadiene or mixture thereof, with molecular oxygen in the vapor phase at a reaction temperature of about 250C to about 600C in the presence of catalyst, and optionally in the presence of steam, the improvement whlch comprises using as a catalyst a catalyst described by formula I
Mol2PaBibCucxdOf ~l 25 wherein X is a halogen selected from the group con-'l sisting of chlorine, bromine or iodine;
~l and wherein a, b and c are numbers ~rom 0.001 to 10;
~:, d is from 0.001 to 5;
f is a positive number of oxygens required to satisfy the valence states of the other elements present; or i~

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( l~'361 ) 6 3 ) (4964) ~ 8 3~ S (~965) using as a catal~st a catalyst described by formula II
~CaMol2Pb~ScOx wherein X is at least one element selected from the group consisting of Sn, rare earth metal, Zr, Rh, Mn Re, Ru, Cu, Pb, Zn, Ti, Cr, Nb, Al, Ga and alkaline earth metal;
and wherein a is a positive number less than about 20;
b and c are numbers from 0.001 to 10;
x is the number of oxygens re~uired by the valence states of the other elements present;
or using as a catalyst a catalyst described by formula III
a 3 b x wherein X is at least one element selected from the group consisting of As, Rb, Pd, Cd, Cs, Tl and In;
and wherein a is a positive number less than about 10;
b is a positive number less than about 3~
x is the number of oxygens required to sat-isfy the valence states of the other elements present; or using as a catalyst a catalyst described by formula IV
XaMl2PbRbcOx wherein X is at least one element selected from the group consisting of Sn, rare earth element, Ni, Zr, Ba, Fe, Rh, Mn, Re, Ru, Co and Cu;
and wherein a is a positive number less than about 20;
b and c are numbers from 0.001 to 10;
x is the number of oxygens required by the valence states of the other elements present.
Especially high yields and selectivities of maleic anhydride are obtained from four-carbon hydrocarbons in an efficient, convenient, and economical manner at a relatively low temp-erature. The exotherm of the reaction i5 low, thereby allowing easy reaction control.
The most significant aspect of the present inven-tion is the catalyst employed. The cai,;alyst may be any of ~831~S

the catalysts delineated by formulae I to I~. The catalysts of the invention have prefer~ed limi-tations on their composi-tion.
When catalysts within formula I are employed, pre-ferred are catalysts wherein a, _, and c are numbers from O.Ol to 5 and d is from O.OOl to lØ Also preferred are catalysts wherein a is O.S to l.5, catalysts wherein _ is O.l to l.0, catalysts wherein c is O.l to l.0, and catalysts wherein d is O.Ol to 0.5. Catalysts of particular interest are described wherein d is 0.005 to O.l. Especially preferred are catalysts wherein X is chlorine.
When catalysts within formula II are employed, pre~
ferred catalysts are described wherein ~ is a positive number ;i .
less than about 12, catalysts wherein b is O.Ol to 5, and catalysts wherein c is O.Ol to 5. Highly desirable results ~ -are obtained wherein b is 0.5 to l.5 and c is O.l to lØ ~ ~
Preferred catalysts are described wherein each element de- ~ -lineated by X is separately incorporated into the catalyst.
Especially preferred catalysts are described wherein X is copper in combination with at least one of the remaining elements, also delineated by X.
When catalysts within formula III are employed, preferred catalysts are described wherein a is a positive number less than about 7, and catalysts wherein b is a positive number less than about 2. Highly desirable results are obtained wherein a is O.Ol to 3 and b is O.Ol to lØ
Catalysts of special interest are described wherein X is at least one element selected from the group consisting of rubidium, cesium, thallium and indium. E~cellent results are obtained wherein each element delineated by X in the catalytic formulais separately incorporatec1 into the catalyst.

( 1! 9 6 1 ) ( ~! 9 6 3 ) ( 1! 9 6 4 ) ( L, 9 6 5 ) ~0~33~L~S

When catalysts withln formula IV are employed, preferred catalysts are described wherein a is a positive number less than about 12; catalysts wherein b is 0.01 to 5;
and catalysts wherein c is 0.01 to 5. Especially preferred catalysts are described wherein b is 0.5 to 1.5 and c is 0.1 to lØ Highly desirable catalysts are described wherein X
is at least one element selected from the group consisting of Ni, Cu, Sn, and a rare earth element.

~he methods of preparing the catalysts of the present invention may vary widely. A number of techniques are known to those skilled in the art. Methods of catalyst preparations such as coprecipitationg evaporative drying, or o~ide mixing, followed by calcining the resulting catalysts may be successfully employed.
The preferred procedure ~or preparing catalysts within formulae I to IV involves preparing the catalysts in an aqueous slurry or solution of compounds containin~ molyb~
denum and phosphorus, adding the remaining components; and evaporating this aqueous mixture. However, when catalysts within formula II are prepared, the preferred procedure involves preparing the catalysts in an aqueous slurry or so]ution of compounds containing molybdenum, arsenic and/or phosphorus and then adding the remaining compounds. Suit-able molybdenum compounds that may be employed in the prep-aration of the catalysts delineated by formulae I to IVinclude molybdenum trioxide, phosphomolybdic acid, molybdic acid, and ammonium heptamolybdate. Excellent results are obtained using catalysts of the invention wherein at least part of the molybdenum employed in the preparation of the 3 catalysts is supplied in the form of molybdenum trioxlde.
Suitable phosphorus compounds that may be employed in the ( 1-' 9 ~
(11963) 6 4 ) ( 1!965) 10831~5 preparation of the catalysts include orthophosphoric acid, metaphosphoric acid, triphosphoric acid, phosphorus halides or oxyhalides. ~he remaining components of the catalysts may be added as oxide, acetate, formate, sulfate, nitrate, carbonate, halide and oxyhalide.
It is important to note that when catalysts within formula I are prepared, especially preferred are catalysts wherein bismuth is supplied in the form of a bismuth halide ~ -~
or oxyhalide. It is not clearly understood where the halo-gen atom is located in the catalytic structure. Infra~red analysis reveals that the catalysts are mostly phospho-molybdate-based and that the halogen is most probably present as a molybdenum oxyhalide.
Excellent results are obtained by refluxing phos-phoric acid and molybdenum trioxide in water for about 1.5 -to 3 hours, however, commercial phosphomolybdic acid may be effectively utilized; adding the remaining components to the aqueous slurry and boiling to a thick paste, where at least one of the components is added as a halide or oxyhalide; and drying at 110C to 120C in air. Howe~er, when catalysts within formula II are prepared, the best results are obtained when the catalysts are calcined following the drying step.
he catalysts within formulae III and IV may also be prepared by mixing the catalytic components in an aqueous slurry or solution, heating the aqueous mixture to dryness; and calcining the resulting catalysts.
; With the exception of catalysts within catalyst II, by the preferred procedure of the in~ention calcination is not generally required to obtain desired catalysts.

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, (~1961) 63) ,~. ( 4964 ) (l~965) ~8 3~ ~ S
However, calcination may be accomplished by heating the dry catalytic components at a temperature of about 300C to about 700C, ~ith preferred calcinatioll being accomplished at a temperature of 325C to 450C. The hydrocarbon reacted may be n-butane, n-butenes, 1,3-butadiene or a mixture thereof. Preferred is use of 1,3-butadiene, n-butenes or a mixture of hydrocarbons that are produced in refinery streams.
The molecular oxygen is most conveniently added as air, but synthetic streams containing molecular oxygen are also 0 suitable. In addition to the hydrocarbon and molecular oxygen, other gases may be added to the reactant feed. For example, steam or nitrogen could be added to the reactants.
The ratio of the reactants may vary widely and are not critical. The ratio of the hydrocarbon to molecular ;
oxygen may range from about 2 to about 30 moles of oxygen per mole of hydrocarbon. Preferred oxygen ratios are about 4 to about 20 moles per mole of hydrocarbon.
The reaction temperature may vary widely and is ~ dependent upon the particular hydrocarbon and catalyst employed. Normally~ temperatures of about 250C to about ~; 600C are employed with temperatures of 250C to 450C
belng preferred.
The catalyst may be used alone or a support could be employed. Suitable supports include silica, alumina, Alundum, silicon carbide, boron phosphate, zlrconia, and titania. The catalysts are conveniently used in a fixed-bed reactor using tablets, pellets or the like or in a fluid-bed reactor using a catalyst preferably having a particle size of less than about 300 microns. The contact time may be as low as a fraction of a second or as high as 20 seconds or ., . j , .. .. .. .. , , . . ;
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(1~961) (11963) ,, (~1964) ~831~5 ( 4g65) more. The reaction may be conducted at atmospheric, super-atmospheric or subatmospheric pressure.
Excellent results are obtained using a coated catalyst consisting essentially of an inert support material having a diameter of at least 20 microns and an outer sur-face and a continuous coating of said active catalyst on said inert support strongly adhering to the outer surface of said support.
By use o~ these coated catalysts in the reaction to produce maleic anhydride, a very low exotherm is realized allowing for better control of the reaction. High single pass yields are exhibited and the elimination of undesirable byproducts is obtained.
The special coated catalyst consists of an inner-support material having an outside surface and a coating ofthe active catalytic material on this outside surface.
These catalysts can be prepared by a number of different methods.
The support material for the catalyst forms the inner core of the catalyst. This is an essentially inert support nad may have substantially any particle size of shape although a diameter of greater than 20 microns is preferred. Especlally preferred in the present invention for use in a commercial reactor are those supports which are spherical and which have a diameter of about 0.2 cm. to about 2 cm. Suitable examples of essentially inert support materials include: Alundum, silica, alumina, alumina-silica, silicon carbide, titania and ~irconia. Especially preferred among these supports are Alundum1 silica, alumina and alumina-silica.

. ' ' ', ' ' ' ' , , ('119~1) 6 3 ) fj 4 ) 33~5 ( ~ 5 ) The catalysts may contain essentially any pro-portions of support and catalytically active materlal. The limits of this relationship are only set by the relative ability of the catalyst and support material to accommodate each other. Preferred catalysts contain about 10 to about 100 percent by weight of catalytically active material based on the weight of the support.
The preparation of these coated catalysts can be accomplished by various techniques. The basic method of preparing these catalysts is to partially wet the support material with a li~uid. The support should not be wet on the outside surface of the total mass. It should appear to '~
be dry to the touch. If the support is wet, then the active ~, catalytic material may agglomerate into separate aggregates , ,~
when coating of the support is attempted. These partially wet support3 are then contacted with a powder of the cat-alytically active material and the mixture is gently agitated until the catal~st is formed. The gentle agitation is most conveniently conducted by placing the partially wet support in a rotating drum or ~ar and adding the active catalytic material. This is very economically done.
Using the catalysts of the invention in the prep-aration of maleic anhydride, excellent yields are obtained in a convenient reaction with low amounts of byproducts.

SPECIFIC_EMBODIME~TS

Examples 1 to 60: Preparation of Maleic anhydride Vsing Yarious Catalysts of the Invention.

F,xamples l to 5: Preparation of r~laleic Anhydride Using Catalysts Des~ribed Within Formula I.

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(~1961) ~ 63) (4961l) (4~65) 3~ 5 Example l A catalyst of the formula Mol2Pl.32Bio.5cuo~25 Clo 06f was prepared as follows: A slllrry was prepared of 86.4 grams (0.60 mole Mo) of molybdenum trioxide and 7.6 g. (o.o67 mole P) of 85 % phosphoric acid in 500 mls. of distilled water; boiled with stirring for three hours to form phosphomolybdic acid which was yellowish green in color. To this surry was added 2.5 g. (0.0125 mole Cu) of copper acetate; no change in color, followed by the addition of 7.9 g. (0.025 mole Bi) of bismuth chloride dissolved in 4.0 ml. of concentrated hydrochloric acid. The mixture was boiled to dryness; dried overnight at 110C in air. The catalyst was ground and screened to lO/30 mesh fraction.
A portion of the catalyst partlcles were charged to a 20 cc. fixed-bed reactor equipped with a l.02 cm.
lS inside diameter stainless steel tube.
The reactor was heated to reaction temperature under a flow of air and a feed of l,3~butadiene/air, as indicated below, was fed over the catalyst at an apparent contact time of 3 to 4 seconds and the performance evaluated by collecting and analyzing the products.
The results of these experlments appear in TABLE
I. The following deflnitions are used in measurlng the carbon atoms in the feed and in the product: -% Single pass yield = M~Oles-oof MydrOcarbnhondrindteheReFeovdred x lO0 Total Conversion Moles Of HYdrocarbon in the peed x lO0 Selectivity = Single Pass Yield x lO0 ~otal Conversion ': " - ' , ';, 1~33~

Examples_2 to 5 T~E I -~

Preparation of Maleic Anhydride From - -1,3-butadiene Using the Catalyst Mol2P1 32Bio sCU0.25C10.06f Feed Temp.C. Ratio Results, %
Exc~le Bath Exotherm Air/HC Ibtal Acid Mal_ic Anhydride Selectivity

2 301 310 23~.31 6.97 83.9

3 317 329 ~148.10 44.09 91.7 : ~- . . .

4 333 351 3453.47 47.88 89.6 3~9 379 2752.67 47.07 89.4 In the same manner catalysts containing different amounts of phosphorus, bismuth, copper and chlorine are used to prepare maleic anhydride from 1,3-butadiene.
Also, in the same manner, various catalysts of the invention are promoted with elements such as Mn, Rh, Ru, Ti, Zn, Re, Pb, rare earth element, In, Sn, Zr, Cr, Pd or mix-ture thereof to produce desirable yields of maleic anhydride fron n-butane, n-butenes, 1,3-butadiene or mixture thereof.

Examples 6 to 23: Preparation of Maleic Anhydride Using ;~
Catalysts Described Within Formula II

_xamples 6 to 8 Various catalysts described within formula II ~''4 ' "',;.
.:.' . ' were prepared as follows: ;
'' `'i', MoI2P1 32As0~5Cuo-25 x A slurry consisting of 317.8 grams of ammonium heptamolybdate, ~NH4)6Mo7O24 4H2O and 1500 mls. of dis-;''' ' ','' : .
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.

(11961) _ (l196~) 831~;5 (4965) tllled water was boiled with stirring. To this slurry was added 11.91 grams of ammonium arsenate~ NH4H2AsOL~ and heating was resumed for 20 minutes; the color was white.
Upon the addition of 7.5 grams of copper acetate, the color changed to light blue. To this mixture was added 22.8 grams of phosphoric acid, H3P04 (~,5~ solution)~ and 10 minutes later 7.5 grams of hydrazine were added to give a dark blue solution which was evaporated to a thick paste, dried over~ -night at 100C to 120C and ground and screened to less than 50 mesh. The resulting catalyst was calcined l hour at 371C in 40 mls./minute air.

Example 7 ~lol2pl.32Aso.5cuo.2oc-4ox ; A slurry was prepared consisting of 105.9 grams of ammonium heptamolybdate, 700 mls. of 60C distilled ~;
water and 3.97 grams of ammonium arsenate as solution in 25 mls. water; a white precipitate formed which was heated to boiling for 45 minutes. To this mixture was added 15.2 grams of chromium oxide; 15 minutes later 2.4 grams of copper acetate were added; and one-half hour later 7.6 ~rams of 85% phosphoric acid was added. The solution was boiled to a thick paste; dried in an oven overnight at 110 to 120C; and ground and screened to less than 50 mesh size.

Calcination was the same as described in Example 2.

Example_8 25%M12Pl.32Aso.sCu0.2oCr4~x + 75% Alundum (coated) This catalyst was prepared in the same manner described in Example 3, except the dry catalytic particles ' '' ' ' ' ' , ( ~l9til ) (43 ( 11 9 ,~
~ ( 4 9 ~; 5 ) were coated on 1/8" SA5223 Alundum balls by taking 50 grams of Alundum, partially wetting the Alundum with 1.8 grams of water and adding 16.7 grams of active catalyst prepared ~
above in five equal portions. During and after each addi- -tion, the Alundum was rolled in a glass ~ar. The powder was -evenly coated onto the surface of the Alundum and the final product was dried. The hard uniform coated catalyst was obtained that consisted of the Alundum support with the continuous, strongly adhering coating of the active cat-alyst. T~e catalyst was then calcined for 2 hours at 371C
in 40 ml./min. air.

Examples 9 to 23 Preparation o~ Maleic Anhydride from 1,3-butadlene A portion of the catalyst particles prepared in accordance with Examples 6 to 8 were charged to a 20 cc. -~
~ixed-bed reactor equipped with a 1.02 cm. inside diameter stainless steel tube.
~ ~he reactor was heated to reaction tempera-ture under a flow of air and a feed of 1,3-butadiene/air as indicated below was fed over the catalyst at an apparent contact time of 3 to 4 seconds and the performance evaluated by collecting and analyzing the products.
The results of these experiments appear in ~A~LE II. ~
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( I, n6 i, ) 10~33~t;S ( ! a65 ) Examples ~4 to 50: Pre~aration of Malelc ~nhydride ~Jsing C~talvsts nescribed Within Formula III
_ ~xamples 24 to 27 Various catalysts described within formula III
were prepared as follows:

~xample 24 Rbo 5Mo3P0 33x An a~ueous slurry was prepared by adding 55.3 grams of molybdenum trioxide to one liter of boiling dis-tilled water with stirring; the slurry was boiled for about 2 hours. To this aqueous slurry, 4.9 grams of 85~ solution phosphoric acld was added; the color of the slurry changed to yelIow. About 200 mls. of distilled water was added to , maintain an approximately 800 mls. solution level. To this aqueous mixture, 7.5 grams of rubidium carbonate were added;
the color of the slurry became bright yellow; after about 30 -~
minutes 25 mls. of distilled water were added. The catalyst was heated with stirring; boiled to dryness; and dried to air at about 110C. The catalyst was ground and screened to give a 10 by 30 mesh fraction.
''~ , Rxamples 25 to 27 Various catalysts of the present invention were prepared. These catalysts have the general formula X0 5- ~;
Mo3P0 33x The catalysts were prepared according to the procedure of Example 1, except 86.2 grams of MoO3, and 7.7 grams of 85~ H3P04 were employed. The element delineated by X was added following the addition of phosphoric acid. To prepare the catalysts, the following compounds and amounts were used:

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6 1 ) ~1~96~) '9611 ) ~L0~331~ 965 ) Example ~lement, ~ = Compound Amount~_~.
25 Cs cesium acetate 19.2 26 Tl thallous acetate 26.3 27 In indium acetate 29.2 ~ollowing the addi~ion of the element, X, the catalysts were boiled to dryness, dried in air, ground and screened in the same manner described in Example 1.

Examples 28 to 46 Preparation of Maleic Anhydride from Butene-2 A portion of the catalyst particles prepared in accordance with .xamples 25 to 27 were charged to a 20 cc.
fixed-bed reactor equipped with a 1.02 cm. inside diameter stainless steel tube.
~he reactor was heated to reaction temperature under a flow of and a feed of air/butene-2/H2O, as indicated below, was fed over the catalyst at an apparent contact time of 1.0 to 1.5 seoonds and the performance evaluated by collecting and analyzing the products. The results of these experiments appear in TABLE III.
' Examples 47 to 50 Preparation of Maleic Anhydride From Butene-2 Using Supported Catalysts Various catalysts were prepare~ using the catalyst of ExamPle 2 having the formwla Cso~5~o3P0~330x d 30% by weight of low surface area supports (i.e. ~ 20m2/gram).
These catalysts were reacted with butene-2 and air in the same manner described above. The results of these experi-ments appear in ~ABLE IV.

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X oX o~ oX ~,, ,~o ,~3o X~ ' I` r` 1` ~ 7~ '`~'~ ;'` ' " ' , . , ~l961) (l!963) ( 1!964 ) 33~L65 (l~965) Examples 51 to 60: Preparation of Ma]eic Anhydride Using Catalysts Described ~ithin ~ormula IV

A catalyst of the formula Nio 2CuO 25~12Pl 32-Rb20X was prepared as follows:
A slurry was prepared of 86.4 grams (o.6 mole) of molybdenum trioxide and 7.7 grams (o.o67 mole) of 85% phos- -phoric acid in 800 mls. of distilled water; boiled with stirring for two hours which was yellew greenish in color.
0.74 grams (0.01 mole) of nickel oxide were added to the slurry; no change in color, followed by the addition of 2.49 grams (0.0125 mole) of copper acetate hydrate and no change in color was observed. Boiling was continued for an addi-tional l.S hours, heating was discontinued, distilled water was added to the mixture to bring the volume up to 800 mls., and the slurry was allowed to stir overnight. The next day 14.4 grams (0.1 mole) of rubidium acetate were added and a heavy yellow precipitate immediately formed. This mixture was boiled to a thick paste and dried in an oven at 110-120C overnight. The catalyst was ground and screened to20/30 mesh size.
The reactor was constructed of a 1.02 c~. inside diameter stainless steel tube. A portion of the aatalyst fraction was charged to the 20 cc. reactlon zone of the reactor.
The reactor was heated to reaction temperature and a ~eed of air/butene-2, as indicated ~elow, was fed over the catalyst at an apparent contact time Ol 1.0 to 1.5 seconds and the performance was evaluated by collecting and analyz-lng the products.
The results of the experiments appear in the Table V in Examples 53 to 60.

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Example 52 ,, Preparation of ~aleic Anh _ride from 1~3-Butadi_ne In the same manner described above, the catalyst 0.2C 0.25~o12Pl.32Rb2~x was reacted with air and 1,3-butadiene. An air/1,3-butadiene feed of 84/1 was passed over the catalyst at a reaction temperature of 285C at an apparent contact time of 1.5 seconds. The results of this experiment showed a 17.8% single pass yield of total acid.

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Claims (41)

WE CLAIM:

1. In a process for the preparation of maleic anhydride by the oxidation of n-butane, n-butenes, 1,3-butadiene or mixture thereof with molecular oxygen in the vapor phase at a reaction temperature of about 250°C to 600°C in the presence of a catalyst, the improvement com-prising using as a catalyst a catalyst described by formula I
Mo12PaBibCucXdOf wherein X is a halogen selected from the group con-sisting of chlorine, bromine or iodine;

and wherein a, b, and c are numbers from 0.001 to 10;

d is from 0.001 to 5;

f is a positive number of oxygens required to satisfy the valence states of the other elements present;

or using as a catalyst a catalyst described by formula II
XaMo12PbAscOx wherein X is at least one element selected from the group consisting of Sn, rare earth metal, Zr, Rh, Mn, Re, Ru, Cu, Pb, Zn, Ti, Cr, Nb, Al, Ga and alkaline earth metal;

and wherein a is a positive number less than about 20;

b and c are numbers from 0.001 to 10;

x is the number of oxygens required by the valence states of the other elements present;

or using as a catalyst a catalyst described by formula III
XaMo3PbOx wherein X is at least one element selected from the group consisting of As, Rb, Pd, Cd, Cs, Tl and In;

and wherein a is a positive number less than about 10;

b is a positive number less than about 3;

x is the number of oxygens required to sat-isfy the valence states of the other elements present;

or using as a catalyst a catalyst described by formula IV
XaMo12PbRbcOx wherein X is at least one element selected from the group consisting of Sn, rare earth element, Ni, Zr, Ba, Fe, Rh, Mn, Re, Ru, Co and Cu;
and wherein a is a positive number less than about 20;
b and c are numbers from 0.001 to 10;
x is the number of oxygens required by the valence states of the other elements present.

2. The process of claim 1 wherein the catalyst is described by the formula Mo12PaBibCucXdOf wherein X is a halogen selected from the group con-sisting of chlorine, bromine or iodine;
and wherein a, b, and c are numbers from 0.001 to 10;
d is from 0.001 to 5;
f is a positive number of oxygens required to satisfy the valence states of the other elements present.

3. The process of claim 2 wherein a, b and c are numbers from 0.01 to 5 and d is from 0.001 to 1Ø

4. The process of claim 2 wherein a is 0.5 to 1.5.

5. The process of claim 2 wherein b is 0.1 to 1Ø

6. The process of claim 2 wherein c is 0.1 to 1.0 .

7. The process of claim 2 wherein d is 0.005 to 0.1.

8. The process of claim 2 wherein d is 0.01 to 0.5.

9. The process of claim 2 wherein X is chlorine.

10. The process of claim 2 wherein the catalyst employed is Mo12Bi0.5P1.32Cu0.25Cl0.06Of.

11. The process of claim 2 wherein 1,3-butadiene is reacted.

12. The process of claim 1 wherein the catalyst is described by the formula XaMo12PbAscOx wherein X is at least one element selected from the group consisting of Sn, rare earth metal, Zr, Rh, Mn, Re, Ru, Cu, Pb, Zn, Ti, Cr, Nb, Al, Ga and alkaline earth metal;
and wherein a is a positive number less than about 20;
b and c are numbers from 0.001 to 10;
x is the number of oxygens required by the valence states of the other elements present.

13. The process of claim 12 wherein a is a pos-itive number less than about 12.

14. The process of claim 12 wherein b is 0.01 to 5.

15. The process of claim 12 wherein c is 0.01 to 5.

16. The process of claim 12 wherein b is 0.5 to 1.5 and c is 0.1 to 1Ø

17. The process of claim 12 wherein X is copper.

18. The process of claim 12 wherein X is copper and chromium.

19. The process of claim 12 wherein 1,3-butadiene is reacted.

20. The process of claim 12 wherein the catalyst is coated on an inert support.

21. The process of claim 20 wherein the catalyst consists essentially of an inert support material having a diameter of at least 20 microns and an outer surface and a continuous coating of said active catalyst strongly adhering to the outer surface of said support.

22. The process of claim 21 wherein the active catalyst is about 10 to about 100 percent by weight of the inert support.

23. The process of claim 21 wherein the inert support is selected from the group consisting of silica, alumina, alumina-silica, silicon carbide, titania and zir-conia.

24. The process of claim 21 wherein the particle size of the inert support is 0. 2 cm. to 2 cm.

25. The process of claim 1 wherein the catalyst is described by the formula XaMo3PbOx wherein X is at least one element selected from the group consisting of As, Rb, Pd, Cd, Cs, Tl and In;
and wherein a is a positive number less than about 10;
b is a positive number less than about 3;
x is the number of oxygens required to sat-isfy the valence states of the other elements present.

26. The process of claim 25 wherein a is a pos-itive number less than about 7.

27. The process of claim 25 wherein b is a pos-itive number less than about 2.

28. The process of claim 25 wherein a is 0.01 to 3 and b is 0.01 to 1.

29. The process of claim 25 wherein X is at least one element selected from the group consisting of Rb, Cs, Tl and In.

30. The process of claim 25 wherein X is rubidium.

31. The process of claim 25 wherein X is cesium.

32. The process of claim 25 where in X is indium.

33. The process of claim 25 wherein X is thallium.

34. The process of claim 25 wherein the active catalytic material is supported on titania, zirconia, alum-ina, or silica.

35. The process of claim 25 wherein n-butenes are reacted.

36. The process of claim 1 wherein the catalyst is described by the formula XaMo12PbRbcOx wherein X is at least one element selected from the group consisting of Sn, rare earth element, Ni, Zr, Ba, Fe, Rh, Mn, Re, Ru, Co and Cu;
and wherein a is a positive number less than about 20;
b and c are numbers from 0.001 to 10;
x is the number of oxygens required by the valence states of the other elements present.

37. The process of claim 36 wherein a is a pos-itive number less than about 12.

38. The process of claim 36 wherein b is 0.01 to 5.

39. The process of claim 36 wherein c is 0.01 to 5.

40. The process of claim 36 wherein b is 0.5 to 1.5 and c is 0.1 to 1Ø

41. The process of claim 36 wherein X is at least one element selected from the group consisting of Ni, Cu, Sn, and a rare earth element.