FR2716634A1 - Hetero:poly:anion-based catalyst system - Google Patents

Abstract

A catalytic system based on a prod. represented by the formula: HmMepPMo12-xVxO40 (I). H is a proton; 6 > m \- 0; Me is a metallic ion, partic. a transition metal; t > p > 0 (t depends on the charge of corresp. ion); and 3 \- x \- 0. It is prepared by reacting in aq. soln. the heteropolyacid H3+xPMo12-xVxO40 with barium hydroxide and one or more salts of a metal(s), with pptn. of the corresp. Ba salt, followed by complete evapn. of the soln. Also claimed is the application of the system to the prepn. of an alpha-beta ethylenic unsatd. carboxylic acid or ester, by vapour phase oxy-dehydrogenation of the corresp. satd. acid or ester.

Description

CATALYTIC SYSTEM CONTAINING OXYGEN MOLYBDENE. OF

  PHOSPHORUS AND AT LEAST ONE TRANSITION METAL. AND HIS

  APPLICATION TO OXYDESHYDROGENATION OF CARBOXYLIC ACIDS

SATURES OR THEIR ESTERS

  The present invention relates to catalytic systems containing oxygen, molybdenum, phosphorus and at least one transition metal, to which can be linked, in variable proportion, protons and vanadium cations, for the purpose of the oxidationhydrogenation reaction. saturated carboxylic acids or their esters to the corresponding unsaturated acids or esters, in particular for the acid oxidation hydrogenation reaction

  isobutyric acid methacrylic acid.

  Many heteropolyanion catalyst systems have long been known as catalysts in the oxidative dehydrogenation reaction of butyric acid, or its esters, to methacrylic acid or its esters. In J. Catal. 98, 401, 1986, catalysts of the formula H5PMo10V2040 have been described for this reaction. The

  methacrylic acid selectivity is of the order of 60%.

  German patent application DE-A-2,722,375 also describes catalysts obtained by concentration of an aqueous solution of the heteropoly acid of composition H5PMolOV2040 and a copper salt, optionally in the presence of an alkaline salt. the dry residue is then calcined. Such catalysts make it possible to achieve methacrylic acid selectivities of 71-72% and, by

  incorporation of lithium, it can reach 74.8%.

  US Pat. No. 4,314,075 proposes, for the same reaction, catalysts based on the following elements: molybdenum, vanadium, copper and phosphorus and an alkali metal selected from potassium, rubidium or cesium and a or several other metals, as well as oxygen in specific quantitative ratios. All metals are present during the hydrothermal reaction which leads to the aqueous solution of a heteropolyanion. The methacrylic acid selectivities attained in the presence of these

  catalysts are between 60 and 70%.

  European Patent Application EP-A-0 113 084 relates to the use, for the oxyhydroxgenation of isobutyric acid or its esters of methacrylic acid or its esters, of a catalyst based on molybdenum oxides, vanadium, copper and phosphorus, prepared by hydrothermal conversion of molybdenum, vanadium and phosphorus compounds, generally in the absence of alkaline compounds and in the presence of a copper compound, into an aqueous solution of a heteropoly acid, drying of the aqueous solution, where appropriate in the presence of an undissolved material serving as

  support, and calcination of the dry residue.

  European Patent Application EP-A-0 255 639 discloses a mixture of heteropolymolybdate containing vanadium and H3PMo12040 or its salts, and / or H3 + xPMol2-xVxO4o with x = 1, 2 or 3 and / or its salts. The salts are obtained by addition of metal compounds (hydroxides, carbonates, nitrates,

  phosphates) to mixtures of heteropolyacids.

  All these catalytic systems derived from heteropolyanions, however, have the average defect of having a limited stability over time under the conditions of the

oxidationhydrogenation reaction.

  There is therefore a need to have catalysts of the heteropolyanion type making it possible to obtain selectivities of commercially acceptable unsaturated carboxylic acids associated with high conversions of the saturated carboxylic acid starting materials subjected to the catalytic oxidationhydrogenation reaction, these catalysts also having to remain stable over time in the reaction conditions. To meet this objective, it is proposed, in accordance with the present invention, a catalytic system based on a product corresponding to the general formula (I): HmMepPMO12_xVxO40 (I) in which: - H represents a proton with 0 <m <6; Me is a metal ion, in particular an ion of a transition metal with 0 <p <t, t depending on the charge of the corresponding ion; and - 0 <x 5 3, and prepared by an aqueous solution reaction of the heteropoly acid H3 + XPMO12_xVxO40, wherein x is as defined above, with barium hydroxide and one or more salts of a Me metal or metals Me, with precipitation of the corresponding barium salt, followed by drying of the aqueous solution until complete evaporation of the solution, generally at a temperature of the order of -150 ° C and for a period of time between 8 and

15 hours.

  Me is in particular an ion of a transition metal, the latter being chosen inter alia from copper, cobalt, iron, silver, nickel and nickel.

  manganese; I can also be, among others, magnesium.

  t is for example equal to 2 for copper and cobalt, and

equal to 1.333 for iron.

  The salts of metals Me are in particular nitrates, carbonates and sulphates; mention may in particular be made of nitrates, carbonates and sulphates of Cu, No and Ni, and

  especially the nitrates and sulphates of Cu.

  The heteropoly acid of formula H3 + XPMo12-xVxO40 is prepared in a known manner (see, for example, Courtin, Rev. of Mineral Chemistry 8, 75, 1971). The continuation of the preparation constitutes an essential characteristic of the present

invention.

  The catalyst system of the invention is advantageously in the form of pellets or grains, obtained by compression of powders, pelletizing, granulation or extrusion. To carry out such shaping, the product of formula (I) may be mixed with at least one dilution material chosen in particular from graphite, talc, stearic acid and the various stearates known for this purpose, and used generally. in a proportion of 1 to 10% by weight, and preferably an amount of about 3% by weight relative to the catalytic system resulting from the mixture. In a known manner, graphite is used only in the case of placing

shaped by pelletizing.

  In accordance with a preferred embodiment, the pellet or granular catalyst system further comprises, for final shaping, pellets or grains of at least one diluent selected in particular from SiC and SiO 2, the weight ratio of pastilles or granules based on the product (I) with pellets or grains of diluent being: 90 to 90:10, and more particularly of the order of

: 70 to 40: 60.

  The present invention also relates to a process for the manufacture of an ethylenically unsaturated carboxylic acid, or an ester of such an acid, by vapor phase oxidation of the saturated acid or the acid ester. corresponding saturated method, said method comprising contacting the saturated carboxylic acid or the saturated carboxylic acid ester with molecular oxygen or an oxygen-containing gas and, if appropriate, an inert diluent gas, if appropriate in the presence of water to ensure a good course of the reaction, in the presence of a catalyst system as defined above, with an overall volume of load per volume of catalyst system (catalyst proper + dilution material (s) and diluent (s)) per hour (VVH) between 500 h -1 and 5000 h -1, preferably 500 h -1 and 2000 h -1, at a reaction temperature of 280 C and 400 C, preferably between 300 ° C and 340 ° C, under a pressure of e 0 to relative bars, preferably from 0 to 2 bars, the proportion of the starting acid or ester in the reaction mixture being between 0.5 and 10 mol%, preferably between 2 and 6 mol% the molar ratio of oxygen to the starting acid or ester being between 0.2 and 5, preferably between 0.5 and 3, the molar ratio of water to acid or ester starting from 0

  and 30, preferably between 0 and 10.

  This type of reaction generally takes place in a fixed-bed tubular reactor whose overall operation can be described by the theoretical model of the piston reactor. The operating conditions in such a circuit include the following: a feedstock sent to the previously shaped catalyst comprises a gaseous mixture, generally preheated, consisting of saturated acid or ester, molecular oxygen, water and an inert gaseous diluent,

such as nitrogen or helium.

  The water introduced into the reactor is understood of course to the exclusion of the amount of water generated, as is well known, by the actual oxidative dehydrogenation reaction. The values of VVH above correspond substantially to a contact time between the charge and the catalyst system which is between 0.1 and 50 seconds,

  preferably between 0.2 and 4 seconds.

  The following examples illustrate this

  invention without, however, limiting its scope.

Example 1

  2.131 kg of M00O3 (99.5% pure), 122.4 g of V205 and 205.2 g of H3PO4 (99% crystallized) are added to 9 liters.

deionized water.

  The slurry thus obtained is brought to boiling under total reflux for 24 hours with stirring, until complete disappearance of the insoluble materials (oxides). At the end of this step, the solution is concentrated to liters, then dried in an oven at 1200C. 2.56 kg of product

  sec (H4PM011oVO40) are thus obtained.

  2.42 kg of H4PM011V040 are dissolved in 2.5 liters of deionized water. The slight haze obtained in this step is removed by filtration. To this solution are added 189.8 g of Ba (OH) 2.8H 2 O. After complete dissolution of the barite, 96 g of CuSO4 are added to the solution. The precipitate of BaSO4 obtained is removed by filtration. The solution obtained is dried in an oven overnight at 120 C, on thin-film trays. 2.09 kg of product (H3Cu0o5PMo11VO40) are thus obtained. 400 g of H3Cu0.5PMo11VO40 are mixed with 14 g of graphite and 10 cm3 of water. After homogenization, the powder is pelletized in the form of annular pellets: inside diameter: 1.5 mm; outer diameter: 5 mm; thickness:

3.2 mm.

  33.2 g of this preparation are mixed with 77.5 g of silicon carbide in the form of pellets 5 mm in diameter and 3.2 mm in thickness (weight ratio of pellets

  of catalyst: silicon carbide pellets = 30:70).

  In view of the oxyhydrogenation of isobutyric acid, this mixture is loaded into a reactor of 21 mm internal diameter. The height of the bed thus obtained is 29.3 cm. The reactor is heated via a salt bath. After loading the reactor under air flow, the flow rates of air and nitrogen are adjusted to achieve the required operating conditions, then water and isobutyric acid liquids are introduced. In a first step, the proportion of isobutyric acid is maintained equal to a value of 2 mol% and then increased after the catalyst system is put into operation at 4.1 mol% and reduced to 3 mol%.

from day 247.

  The other general conditions were as follows: - temperature between 306 and 323 ° C; - H 2 O / isobutyric acid = 1.6 (in moles) O 2 / isobutyric acid = 2.5 (in moles) - contact time = 2.4 s for days 1 and 2 (VVH = 1500 h-1); 3.2 for days 3 to 240 (VVH = 1125 h-1); 3.36 for 245-247 days (VVH = 1071 h-1); 4.4 for 304-305 days; 4.8 for day 308; and 4.6 for days

312-336.

  The results are reported in Table 1.

TABLE 1

  TeqR Cownversaion Selectivity Selectivity Selectivity Selectivity Severity (days) (X) acid Methpropham acetone (Z) acid CO and CO2 crylic (X) (X) _cetic (X) (Z) 0 86.2 76.7 7f4 14.2 1,2 1,1 1 86.2 76.5 SJ8 14.2 1.3 1, l 2 91f? 76.8 8.6 13.5 1.7 1.5

3 91,875.0 84 12.5 1.6 1.6

7 92.6 70.3 8, .. 9 110. 1.4 2.0

9 92.3 75.8 9.4 13.0 1.6 1.9

  10 14 92, 4 74t7 8.9 12.6 16 6 17 90.8 73r7 88 12.1 1.2 2.1 93.1 l85 11.9.6 2.0 93, 1 73.6 e, 8 11, 8 1S8

23 92.9 18 89 10.2 1.7 2.4

28 93.3.7 9.1 115 1.9

93.0 1 96 118 1.7 2.6

93.6 73.1 94 119.5 2.1

38 93.3 72.6 9.6 11.9 1 "1.7

93.7.4 9.2 11.9 1, 2.0

49 74.9 10.1 11.9 1.7 2.2

52 93.5 76.7 9.2 12.2 1.5 2.2

56 93.7 75 1 9.4 119q 1 6 2- 5-

58 93.5 7419.2 12.0 1.5 1.7

94.2 74.7 9.7 12.0 1.7.7

72 93.8 73.2 9.6 12.1 1.8 1.7

77 94.2 72.7 10.3 11r, 15 2.3

938 74.1 10.9 8 1.2 3.2

92 94.1 71.3 10.6 11.7 1.6 2.4

95.4 70.1 106 11.5 2.3 2.0

113 95, 4 71., 5 12 118 2.3 1.8

925 677 109 12.0 1.6 1.8

119 91.8 71.9 10.1 12.6 1.6 0.9

127 90.9 80.2 10.3 14.7 1 0.3

133 91.3 72.1 9.1 13.0 1.9 1.5

  TABLE 1 (continued) Tempe Conversion Selectivity Selectivity SL Selectivity Selectivity Selectivity (days) (Z) Methylated Acetone Z) CO and C2 Cryogenic (Z) (Z) cetlql (O M2 143 90.9, 71.9 11i8 13 , 3 lra8 1.6

146 90.8 71.4 11.8 13.4 1.6 1.7

89.6 73.0 12.0 13.4 0.7 2.0

157 88.2 75.0 12.7 118 16 1.6

  158 91.7 76.6 11l, 1 12.1 3.5 3.3 94.5 72.3 12.3 11, l 2.2 3.6

161 91.8 71.4 10.9 11.7 2.2 2.0

90.7 7Q6 12.0 12.7 3.8 1.2

169 90.6 74.1 11.0 12.8 1.8 2.4

173 92.3 70.8 13.5 12.1 2.3 2.7

176 90.3 72.5 10.3 14.5 4.0 1.0

182 91.2 74.9 10.6 12.7 2.4 1.4

183 89.4 77.7 12.3 14.8 2.2 1.2

184 88.8 72.0 12.2 11.8 1.2 2.4

189 87.9 72.5 12.7 12.1 1.4 2.2

197 U, 5 71.5 13.0 12.4 1.2 1.8

2 0 198 93.2 71.9 13.1 11.3 1.4 2.3

  214 91g0 71.6 13.9 11.1 Ij4 214 219 90.0 71t8 14.0 11.5 1.4 2.2

226 89.4 72.0 15.0 11.7 1.3 2.6

233 95.1 68.1 15.2 11.1 2.0 3.0

239 91.5 7118 16.6 11.4 19q 2.7

240 94.7 68.7 15; 9 10.9 2.2 3_ 0

304 98.2 72.6 10.2 14.0 2.0 1.5

305 987 72.0 10.4 14.1 2.5 2.1

308 98.8 64.6 10.9 12.2 2.2 3.1

312 98.3 74.0 10.6 13.8 1.8 2.6

316 98.4 71.8 11.5 13.5 2.3 2.1

323 98.1 76.2 11rl 13.2 2.1 2.2

336 98.1 74 11.9 12 1.8 2.6

Example 2

  The procedure was as in Example 1, except that a mixture of catalyst pellets - silicon carbide pellets in a weight ratio of 40:60 (57.8 g catalyst pellets, 86.7 g of silicon carbide pellets), that, initially, before the catalyst system was put into operation, the proportion of isobutyric acid was kept at 3 mol%, that the reaction temperature was between 320 and 323C, and that the contact time was 3 seconds on day O (VVH = 1200 h-1) and 3.6 seconds on the other days

(VVH = 1000 h-).

  The results are reported in Table 2.

TABLE 2

  Variability Selectivity S6Lect1vit4 Selectivity S4Lectivity S4ectfvit4 (Days) (X) Acidic Acetone Acid Acid CO and C2 Crystalline> (X) () Acylated (X)

0.1 73.6.7 10.8 1.3 2.9

1,964 73.2 8.8 10.6 1.7 3.4

13 97.2 70.89 94 9.5 2.4 3Z

20 97.1 74.7 9.6 10.4 1.9 3.4

21 97.2.7 10.1 11.0 1.5 3.9

23 97.1 71.6 9.3 10.3 1.1 3.6

56 97.9 73.4 10.4 10.1 2.8 4.1

% 9.8 75.5 10.6 9.4 2.1 4.5

79 9 7.6.0 1112 10.5 2.3 3.1

87 97.9 73.4 10.9 10.7 3.8 3.5

  Example 3 (Comparative) In deionized water, MoO3, V205 and H3PO4 were dispersed in a molar ratio of 1.1: 0.05: 0.15. The mixture thus obtained is then heated for 5 hours under reflux.

and agitation.

  Starting from 575.82 g of the resulting phosphorus compound, 20.34 g of Cu (NO 3) 2 are added, and a silica support is impregnated at the impregnation rate of 44% by weight, and then dried.

at 120 ° C for 12 hours.

  The conditions of manufacture of methacrylic acid from isobutyric acid were as follows: proportion of isobutyric acid in the reaction mixture: 5.1 mol% - VVH = 2000 h -1 H 2 O / isobutyric acid = 2 (in moles) - 02 / isobutyric acid = 1.5 (in moles)

- temperature = 339-341C.

  The results are reported in Table 3. The comparison with the results of Tables 1 and 2 shows the superiority of the catalyst systems of the invention.

  especially from the point of view of stability.

TABLE 3

  Temç Conversion SelectivitySelectivitySelectivity * S $ ectivitySelectivity <(days) (X) matha-ropene acid (2) acetone (X) acid CO and C02 cryetic (2) acetic acid (<) (X)

0 93.4 73.5 8.4 12.8 2.8 2.7

1 92.6 74.2 8.5 13.5 2.5 1.9

4 92.6 75.9 8.4 12.8 2.4 1.8

6 92.2 742 8.5 12.5 2.0 1.7

8 92.6 73.4 8.6 11.9 Z, 0 1.6

  11 91.6 75.5 9.0 12.6 2.1 l9q 1 0 1: 3 92.0 773 1 1 q 2r0 Z, 4

91.0 74.5 8.9 126 22 1

a8 91.7 74.2 8.6 11.7 2.4 1.4

21 91.2 76.5 6.9 12.1 2.3 2.4

29 90.6 74.6 8.6 2.0 25

33 90.8, 4, 8.6, 1.6, 2.4, 0.3.

36 90.5 73.7 10.0 2 2.4

88176.9 11.2 11.6 1 6 2.1

  41 88.6 7,110.6 11.4 1.7 l, 43 88.4 75.6 10.7 11.3 1.6 i1.8

47 88.0 7.7 107 11.4 1.3 2.1

49,899 74.0 1,11 113 19 2,5

54 6282,776.2 _

77.0 80.0r

56 76.9 79.4

57 77.0 81.1

85.2 78.8

80.0 77.0

62 81.5 77.8. ,

67 85 0 76.8

68 87.4 718 11.5 1., s4 1, 9

86.0 73.0.10 ,, 12.3 1.7 2.9

, 889 71.6 11 {1 11 {2 17 3 {1

77,883 70.8 13918 1 J (7 3.1

81 87.8 67.6 11.6 11.7 1.7 2.6

Claims (9)

  1 - Catalytic system & base of a product corresponding to the general formula (I): HmMepPMO12_xVx040. (1) wherein: - H represents a proton with 0: m <6; Me is a metal ion, in particular an ion of a transition metal with 0 <p <t, t depending on the charge of the corresponding ion; and - 0 S x <3, and prepared by an aqueous solution reaction of the heteropoly acid H3 + xPMo12_xVx040, wherein x is as defined above, with barium hydroxide and one or more salts of a metal Me or metals Me, with precipitation of the corresponding barium salt, followed by drying the aqueous solution until complete evaporation of the solution. 2 - catalytic system according to claim 1, characterized in that the aqueous solution has been dried at a temperature of 90-150 ° C for a period of time between 8 and 15 hours.   3 - Catalytic system according to one of the   cations 1 and 2, characterized in that Me is an ion of a transition metal selected from copper, cobalt, iron, silver, nickel and manganese, or a magnesium ion.   4 - Catalytic system according to one of the   cations 1 to 3, characterized in that the salts of   Me metals are nitrates, carbonates or sulphates.   5 - catalytic system according to one of the claims   cations 1 to 4, characterized in that it is in the form of pellets or grains, obtained by compression of powders, pelletizing, granulation or extrusion, the product of formula (I) may have been mixed with at least one   dilution material for its shaping.   6 - Catalytic system according to claim 5, characterized in that it further comprises pellets or grains of at least one diluent selected in particular from SiC and SiO2, the weight ratio of the pellets or grains based on the product (I) with the pellets or grains of diluent being in the range of 10: 90 to 90:10.   7 - Process for producing an α, β-ethylenically unsaturated carboxylic acid, or an ester of such an acid, by vapor phase oxidation hydrogenation of the saturated acid or of the corresponding saturated acid ester, said method of contacting the saturated carboxylic acid or the saturated carboxylic acid ester with molecular oxygen or an oxygen-containing gas and, if appropriate, an inert diluent gas, if appropriate in the presence of water, in the presence of a catalytic system as defined in   one of claims 1 to 6, with a load volume   overall volume per volume of global catalyst system per hour between 500 h -1 and 5000 h -1, at a reaction temperature of between 280 ° C. and 400 ° C., at a pressure of 0 to 10 bar relative, the proportion of the acid or starting ester in the reaction mixture being between 0.5 and 10 mol%, the molar ratio of oxygen to the starting acid or ester being between 0.2 and 5, the molar ratio of the acid water or starting ester being included between 0 and 30.   8 - Process according to claim 7, characterized in that the reaction is carried out at a temperature between 300 C and 340 C, under a pressure of between 0 and 2 bars relative.   9 - Process according to one of claims 7 and 8,   characterized in that the molar ratio of oxygen to the starting acid or ester is between 0.3 and 3, the molar ratio of water to the starting acid or ester is between 0 and 10, and the proportion of starting acid or ester in the reaction mixture is between 2 and 6%, expressed in moles.   - Method according to one of claims 7 & 9,   characterized in that the volume of starting acid or ester per volume of catalyst system per hour is between 500 h-1 and 2000 h-1.