CA1267129A - Carrier-supported catalyst and process for making monocarboxylic anhydrides - Google Patents

Abstract

CARRIER-SUPPORTED CATALYST AND PROCESS FOR MAKING MONO-CARBOXYLIC ANHYDRIDES

ABSTRACT OF THE DISCLOSURE

Monocarboxylic anhydrides of the general formula (RCO)2O
are made by reacting a carboxylic acid ester or dialkylether of the general formulae RCOOR and ROH, respectively, in which R stands for one and the same alkyl radical having from 1 4 carbon atoms, with carbon monoxide in gas phase, in the pre-sence of iodine or bromine or their compounds as a reaction promoter and also in the presence of a carrier-supported catalyst containing noble metal compounds of group VIII of the Periodic System, at temperatures of 130 - 400°C and under pressures of 1 - 150 bars. To this end, a novel carrier-sup-ported catalyst is used in which the carrier material has a noble metal/chelate-compound formed of the noble metal com-pound and a chelator containing organonitrogen, organophos-phorus, organoarsenic or organosulfur groups applied to it.

Description

7 ~

This invention relates to a process for making monocarboxylic anhydrides of the general formula (RCû)20 by reacting a carboxylic acid ester or dialkylether of the following general formulae RCOOR and ROR, respectively, in which R stands for one and the same alkyl group having from 1-4 carbon atoms, with carbon mon-oxide in gas phase, in the presence of iodine or bromine or their compounds as a reaction promoter and also in the presence of a carrier-supported catalyst containing a noble metal com-pound selected from group VIII of the Periodic System of the elements, at temperatures of 130 - 400C and under pressures of 1 - 150 bars.
Processesof this kind which are carried out in gas phase with the use of a carrier-supported catalysthave already been described in German Specification DE~A 24 50 965 and in Japanese Specification No, 479Zl/1975. These processes avoid the di:Efi-culties normally accompanying operations in liquid phase, e,g.
the difficult separation and recycle of suspended and partially dissolved catalyst and, under circumstances, promoter.
The two Specifications describe gas phase processes wherein 2n solid carrier-supported catalysts made by impregnating the carrier material with a dissolved or suspended and even with complex noble metal compounds are used. In this way, it is not possible to fix e.g. an organonitrogen or organophosphorus com-pound containing trivalent nitrogen or phosphorus in the carrier-supported catalyst; this however has been found generally toaffect the catalyst performance and reaction selectivity.
The present invention avoids this deficiency and to this end provides for the catalyst carrier to be impregnated with a noble metal/chelate-compound which has one or more promoters z~

selected from principal group V, 0.g. an organylamine or phos-phine, al.ready integrated in it.
The invention comprises more particularly using 1) a carrier-supported ca-talyst in which the carrier has a noble metal/chelate-compound formed of the noble metal compound and a chelator containing organonitrogen, organo-phosphorus, organoarsenic or organosulfur groups applied to it.
Further preferred and optional ~eatures of the invention 1~ provide:

2) for the carrier of the carrier-supported catalyst to have a non noble metal/chelate-compound formed of a non noble metal compound selected from the 6th or 8th subgroup of the Periodic System of the elements and a chelator con-taining organonitrogen, organophosphorus, organoarsenic or organosulfur groups additionally applied to it;

3) for the carrier-supported catalyst to contain a non noble metal compound selected frorn the 1st through 3rd princi-pal groups or the 4th through 6th or 8th subgroups of the Periodic System of the elements as an additional promoter;

4) for the carrier in the carrier-supported catalyst to have a chelate compound and one o~ the following chelators:

a) (CH2)n Y
b) Y-CH=CH-Y
.~ C) Z12P-CH-CH-P02 d) 02As-CH=CH-As02 ~2~7 e ) 02P-GH2-CH2-P0-CH2-CH2-P~-CH2-CH2-P~2 f ) 02P-CH2-c~l2-P0-cH2-cH2-E02 g) , ~\y ,,I,ry ~ ' h) P( -CH2GH2-P~2) 3 i ) R1 -C/- (CH2)n-Y_73 j) ~CR1) Y

' k) 02P- ( CH2 )x\ / ( CH2 ) x- PIZ)2 02P- (CH2 )x \ (CH2),~P02 in which 0 stands for C6H5-;
Y stands or -NR2, an aryl group containing nitrogen, : -PR2, -AsR2, -SR2 or -SH;
Rl stands for -H, a Cl-cs-alkyl or -C6H5;
R2 stands for a Cl-C6-alkyl, a C5-C8-cycloalkyl or -C6H5 or C6H5CH2-;
n stands for i through 6, presrably 1-4;
m stands for O through 8, preferably 0-3, and x stands for 1 or Z
applled to .it;

5) for the carrier-supported catalyst to contain an inorganic oxidic carrier or an active carbon carrier.

6) for the carrier-supported catalyst to contain altogether 0.01 - 50 wgt %, preferably 0.1 - 20 wgt %, chelate com-pound and non noble metal compound, if desired;

7) for the carrier-supported catalyst to be used in the form of particles having a size of 1 through 20 mm.
The invention also relates to the catalyst itself which is used for making monocarboxylic anhydrides by subiecting a suitable ester or ether to a carbonylation reaction and which is characterized in that the carrier has a noble metal/chelate-compound formed of a noble metal belonging to the 8th subgroup o~ the Periodic System of the elements and a chelator contain-ing organonitrogen, organophosphorus, organoarsenic or organo-sulfur groups applied to it.
Further preferred and optional features of the carrier-supported catalyst of this invention provide:
1) for the carrier to have a non noble metal/chelate-compound formed of a non noble metal selected from the 6th or 8th subgroup of the Periodic System of the elements and a chelator containing organonitrogen, organophosphorus, organoarsenic or organosulfur groups additionally applied to it;
2) for the carrier-supported catalyst to contain a non noble metal compound selected from the 1st through 3rd principal groups or the ~th through 6th or 8th subgroups of the Periodic System of the elements as an additional promoter;

3) for the carrier to have a chelate compound formed of a metal compound and one of the chelators identified under item 4), a) through k) hereinabove applied to it;
4) Eor the carrier-supported catalyst to cDntain an in-organic oxidic carrier or active carbon;
5) for ~he carrier-supported catalyst to cantain alto-gether 0.01 - 50 wgt %, preferably 0.1 - 20 wgt %, chelate compound and non noble metal compound, if desired.
The catalyst carriers which sould preferably be used comprise inorganic oxides, e.g. SiO2, Al203, MgO, TiO2, La203, ZrO2, zeolite, clay, Niû, Cr2û3,-W03 or correspon-ding mixed oxides, but also active carbon having a BET-surface area of 1 - 1000 mZ/g, preferably 3û - 400 m2/g.
15 ~ The promoters of the 5th or 6th principal group are chemically combined in the chelators used and constitute themselves one of their functional groups encasing the noble metal cumpounds selected from group VIII, especially Rh, Ir, Pd, or Ru, and also the non noble metal compounds, if any, selected from the 6th or 8th subgroup, especially Cr or Ni, but also W, Fe and Co, like pincers of a cray-fish One of the advantages of the carrier-supported cata-; lyst and process of this invention resides in the fact that the promoters necessary for increasing the catalyst performance and selectivity and selected from principal group V or VI of the Periodic System of the elements form a functional group Y in the chelators and thus are fixed.
It is therefore unnecessary, e.g. for an organonitrogen or organophosphorus promoter to be separated and recycled.

The present process for making monocarboxylic anhydrides compares favorably in its higher catalyst performance and selectivity with the prior art methods described hereinabove, which are also carried out in gas phase and with the use of a carrier-supported catalyst.
A further advantage of this invention is seen to reside in the fact that the noble metal/chelate-compounds and optionally non noble metallchelate-compounds applied to the carrier fail to commence melting at the reaction temperatures necessary for making monocarboxylic anhy-drides.
The carrier-supported catalyst and process of this invention are more particularly used for making acetic anhydride from methyl acetate or dimethylether in tha presence of methyl iodide or methyl bromide as a reaction promoter. Further suitable promoters are HI, HBr or more ganerally RI or RBr, where R stands for an alkyl group having 1 - 4 carbon atom~s.
The use~ul carrier materials have already been speci-fied hereinabove; useful mixed oxides are, e.g. Cr203-2 3' 3 1203, MgO-A1203, SiU2-A1203 or ZrO2-A1 0 The carrier-supported catalyst should preferably contain 0.01 - 5 wgt % noble metal and present a particle size of 1 to 20 mm.
The noble metal compounds which should conveniently be used for making the present carrier-supported catalyst, comprise e.g. the following compounds Rhodium:
RhC13, RhC13 . 3 H2O, RhBr3, RhI3, ~h(N03)3, Rh2(C0)4C12, 2h2(C0)4er2, Rh(C0)4I2, C P(C6H5)3 73RhCl, ~ P(C6H5)3 ~2 6( )16~ Rh4(c0)l2~ Rh2 (02CCH3)4, L RhCl(C H ) ~
Iridium:
IrCl3, L Ir(C0)3Cl ~2' Ir ~ P(C6H5)3 ]2(C ) , 4 12 ~ IrCl(C8H12) ]2~ Cl(C0)zIrpyr (pyr = C6H5N);
Palladium:
PdC12, PdBr2, PdI2, (CH3cû2)2pdLp(c~Hs)3 ~2' P C 2~ ( 6 5 3 2 ( 2 CH3)2, PdC12(CgHl2)~ (C6H5cN)2Pdcl2;
Ruthenium:
3' 3(C)12' RUCl2C P(~6H5)3 73, RUC12~C0)2[ P(C H ) RUcl2(co)3 J2-Useful non noble metal compounds selected from the 6th or 3th subgroup, especially Cr, Ni, but also W, Fe, Co which also undergo reaction with the chelator, comprise e.g.
the following:
Chromium:
Cr(C0)6, CrC13, C7H8Cr(CO)3.
Nickel:
4 ~ 5)3 ~2Ni(C0)2, NiC12, Ni(C8H12)2 The non noble metal compounds selected from the lst through 3rd principal groups or the 4th through 6th sub-groups or 8th subgroup of the Periodic System of the ele-ments, preferably compounds of Li, Na, Mg, Ca, Al, li, Zr, ~, Cr, W, Fe, Co, Ni are comprised, e.g. of hydroxides, carbonates, carbonyls, hydrides, halides and further salts.
It is possible for these non noble metal compounds to be additionally applied to the catalyst carrier, e.g. in the form of a solution by impregnating the carrier therewith.
for making the carrier-supported catalyst of this in-vention, it is necessary first to have the chelator with the functional groups Y, which is a commercially availableproduct or can be made by methods described in literature.
Speaking generally, the chelator is contacted with a solution of one of the noble metal compounds of group VIII
and, if desired, one of the non noble metal compounds of the 6th or 8th subgroups with the resultant formation, in known fashion, of chelate compounds having ~elting points higher than the temperature commonly employed in a car-bonylation reaction for making monocarboxylic anhydrides.
Next, the carrier material is impregnated with the dissolved con~entional chelate compounds to give the finished catalyst. The solvents for the chelate compounds comprise polar and unpolar solvents, e.g. dlchloromethane (methylene chloride), chloroform, methanol, benzene, toluene or xylene, in which the carrier material is~c;uspen-ded. Details are indicated in the catalyst description hereinafter.
The quantitative ratio of carboxyl.ic acid ester or di-alkylether and iodine(compound) or bromine(compound) in the reaction zone may vary within wide limits. Generally, how-ever, 1 to 500 mols, preferably 1 to 100 mals, carboxy-lic acid ester and/or dialkylether is used per 1 mol iodine' (compound) or bromine(compound). The temperature selected for the reaction zone should be high enough to always have a gaseous reaction mixture therein, irrespective of the conversion rate, and preferably is between 150 and 250C.
The preferred pressure is between 5 and 30 bars.
The reaction mixture should conveniently be contacted with the solid carrier-supported catalyst over a period of from 1 to 1000 seconds, preferably 1 to 180 seconds.

,~d~ G~3 The conversion should suitably be effected in a flow tube arranged in upright position, packed with the carrier-supported catalyst or in an autoclave provided with a stirrer or in a shaking autoclave, having the carrier-supported catalyst placed therein. While the carbonylationis generally effected under practically anhydrous condi-tions, it is allowable for it to be carried out in the presence of minor amounts of water as they are normally found in commercially available starting materials, which however should not exceed 1 mol %, based on the starting materials. In addition, the carbonylation remains substantially uneffected by the presence of minor amounts of methanol in the starting materials or of hydrogen in commercial carbon monoxide.
The reaction mixture coming from the carbonylation zone is gaseous and contains carbon monoxide, methyl iodide, acetic anhydride, unreacted methyl acetate or dimethylether and, under circumstances, minor proportions of acetic acid. The gaseous reaction mixture is cooled with conden-sation of acetic anhydride, under circumstances, acetic acid. Uncondensed gases, such as C0, CH3I, methyl acetate or dimethylether are recycled to the reaction zone, ths reacted ester or ether and C0 portions being continously renewed. The anhydrides are easy to separate, i.e. in uncomplicated fashion, by cooling the effluent reaction mixture and recycling the uncondensed gas. This is a par-ticular advantage of the process of this invention. The carrier-supported catalyst is not contaminated; it remalns ; in the reaction zone. As a result, the entire process is 30 rendered considerably simpler.

7 ~

The following Examples illustrate the invention which is naturally not llmited thereto:
Exa~ples Autoclave test A stainless steel (Hastelloy C) autoc:Lave (capacity 0.25 l) provided with a stirrer, various inlets and outlets and a turnable basket receiving the catalyst was used. The carboxylic acid ester or dialkylether was reacted in gas phase with Cû-gas in the presence of the agitated solid carrier-supported catalyst. The catalyst was placed in the turnable catalyst basket which also permitted the gases to ~e mixed. The autoclave was charged with 2.5 ml of a llquid mixture of 20 volume parts methyl iodide and 8û
volume parts ester or ether, and heated to the reaction temperature. The carbonylation was started by injecting ; carbon monoxide. The C0-pressure was maintained constant by continued injection o gas. Details are indicated in the Examples.
Example 1 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 g)methyl iodide and 1.60 9 catalyst No. 1 were reacted in the auto-clave with carbon monoxide at 180C under a C0-pressure of 2û bars. After a reaction period of 1 h, the catalyst performance was found to be 260 9 Ac20 per 9 Rh per hour.
The yield of Ac20, based on the ester used, was 64 %
and the selectivity 95 %.
Example 2 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.60 9 catalyst No. l-were reacted in the auto-clave with carbon monoxide at 175C under a C0-pressure of 7~

20 bars. After a reaction period of l h, the catalyst perfor-mance was found to be 220 9 Ac20 perg Rh per hour. The yield of Ac20, based on Ihe es~,ar used, was 54 % and the selectivity 96 %.
Example 3 2 ml (1.86 g) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.77 g catalyst No. 2 were reacted in the autoclave with carbon monoxide at 166C under a C0-pressure of 20 bars. After a reaction period of 1 hour , the catalyst performance was found to be 280 9 Ac20 per 9 Rh per hour. The yield of Ac20, based on the ester used, was 64 % and the selectivity 97 %.
Example 4 2 ml (1.86 g) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.77 9 catalyst No. 2 were reacted in the auto-~15 clave with carbon monoxide at 18ûC under a C0-pressure of 20 bars. AEter a reaction period of 1 hour, the catalyst performance was found to be 380 g Ac20 per g Rh per hour.
The yield of Ac20, based on the ester used, was 86 % and the selectivity 93 %.
Example 5 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.78 9 catalyst No. 3 were reacted in the auto-clave with carbon monoxide at 200C under a C0-pressure of 20 bars. After a reaction period of 1 hour, the catalyst performance was found to be 35 9 Ac20 per 9 Rh per hour. The yield of Ac20, based on the ester used, was 11.6 % and the selectivity 87 %.

'7 ~ ~3 ExampLe 6 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.70 9 catalyst Na . 4 were reacted in the auto-clave with carbon monoxide at lB0C under a C0-pressure oF
20 bars. After a reaction period of 1 hour, the catalyst performance was found to be 450 9 Ac20 per 9 Rh per hour.
The yield of Ac20, based on the ester used, was 24 ~O and the selectivity 94.7 ~O.
Example 7 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 4.4 9 catalyst No. 5 were reacted in the auto-clave with carbon monoxide at 180C under a C0-pressure of 20 bars. After a reaction period of 1 hour, the catalys-t performance was 150 9 Ac20 per 9 Rh per hour. The yield of 15 Ac20, based on the ester used, was 78 O and the selectivi-ty 94 ~O.
Example 8 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.7 9 catalyst No. 6 were reacted in the auto-20 clave with carbon monoxide at 180C under a C0-pressure of 20 bars. After a reaction period of 1 hour, the catalyst performance was found to be 190 9 Ac20 per 9 Rh per hour.
The yield of Ac20, based on the ester used, was 45 O and the selectivity 93 ~O.
Example 9 A steel tube 20 mm wide and 450 mm long was used as a flow tube in upright position and charged with 27.4 9 cata-lyst No. 2 which however contained 0.4 wgt O Rh. 11 Nl C0 (Nl = liter measured at 0C under 1.01~ bar) and an evapo-~Z~7~

rated mixture (13 ml liquid) of methyl acetate and methyl iodide (molar ratio 11 : 1) were passed through the flow tube at 172C under a pressure of 12.5 bars.
The effluent reaction mixture was cooled to onc at at-mospheric pressure and analyzed gas-chromatographically.
The space/time-yield was found to be 71 9 Ac20 per liter per hour. The yield of Ac20, based on the ester used, was 30 6 and the selectivity 96 ,6.
The carbonylation reaction was effected over a period of 100 hours under these reaction conditions; the perfor-mance of the carrier-supported catalyst could not be found to have been reduced.
Example 10 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 g) methyl iodide and l.i 9 catalyst No. 7 were reacted in the auto-clave with carbon monoxide at 180nC under a C0-pressul~e of 2û bars. After a reaction period of 1 hour, the catalyst performance was found to be 300 9 Ac20 per 9 Rh~hour. The yield of Ac20, based on the ester used, was 62 6 and the selectivity 95 6.
Example 11 1.86 9 dimethylether, 0.5 mi (1.14 9~ methyl iodide and 1.7 9 catalyst No. 7 were reacted in the autoclave with carbon monoxide at 180nC under a C0-pressure of 20 bars.
After a reaction period of 1 hour, the catalyst performance was found to be 100 9 Ac20 per 9 Rh per hour. The yield of Ac20, based on the ether used, was 20.6 O and the selecti-vi~y 85 ~0.
Example 12 2 ml (1.86 9) methyl acetate, 0.5 ml (1.14 9) methyl . ' .

L~

iodide and 1.7 9 catalyst No. 8 were reacted in the auto-clavs with carbon monoxide at 180C under a C0-pressure of 20 bars. After a reaction period of 1 hour, the catalyst performance was found to be 243 9 Ac20 per 9 Rh per hour.
The yield of Ac20, based on the ester used, was 50.1 O and the selectivity 94 O.
Example 13 2 ml (1.86 g) methyl acetate, 0.5 ml (1.14 9) methyl iodide and 1.7 9 catalyst No. 9 were reacted in the auto-clave with carbon monoxide at 180C under a C0-pressure of 20 bars. After a reaction period of 1 hour, the catalyst ....
performance was found to be 250 9 Ac20 per 9 Rh per hour.
The yield of Ac20, based on the ester used, was 55.0 O and the selectivity 95.5 O.
Description of catalyst preparation In each particular case, the catalyst carrier was ac-tivated by drying it over a period of 10 hours at 200C
under a pressure of about 0.133 millibar. All syntheses were run in the presence of nitrogen with exclusion of oxy-gen and water, and all reagents were previously dried usingmolecular sieve 4 A.
The following abbreviations are used hereinafter dpe = 02P-CH2CH2-P~; dpen = 02P-CH=CH-P02 dpb = 02p-(cH2)4 P~2 Tetraphos~ `2PCH2CH2P0CH2CH2P0cH2cH2P02 Catalyst No. 1 A12û3] r Rh(dpe)2_/+Cl-3 9 activated aluminum oxide balls (99 O A1203) which had a diameter of 3 mm, an inner BET-surface area of 125 m2/9 a pore volume of 0.9 ml/g were added to 150 mg (16 mg Rh) compound of the formula / Rh(dpe)2_/Cl (melting point 217C; prepared from 1,2-bis-(diphenylphosphine)ethane and dichlorotetracarbonyldirhodium, cf. A. Sacco et al., J.
Chem. Soc. (London) 7 (1964), 3274; for preparation of / Rh(C0)2Cl_/2 from RhC13 3H20 and C0-gas, see J.A.
McCleverty et al., Inorg. Synth. 8 (1966), page 211; for preparation of 02PCH2CH2P~2, see W. Hewertscn et al., J.
Chem. Soc. (London), (1962), 1490) dissolved in 100 ml di-chloromethane, under N2.
~he yellow suspension was heated to boiling while stirring and refluxed over a period of 12 hours after which the dichloromethane was found to have been completely deco-lorized. Next, the dichloromethane was removed under redu-ced pressure and the catalyst wa~s dried over a period of 8 hours at 85C under 1.13 millibars.
Yellow pellets containing 0.44 wgt 90 Rh wers obtained.
Catalyst No. 2 -A1203 ¦ / Rh(dpe)2 ~ BF4 3 9 activated aluminum oxide balls (99 90 A1203) which had a diameter of 3 mm, an inner BET-surface area of 125 m2/g and a pore volume of 0.9 ml/g were added to 100 mg (10.4 mg Rh) compound of the formula / Rh(dpe)2_/BF4 (melting point = 270C; prepared the same way as catalyst No. 1 but with an additional anion exchange with AgBF4 for increasing the performance; cf. B.R. James et al., Can. J. Chem. 57, 180 (1979)) dissolved in 100 ml dichloromethane under N2. The yellow suspension was heated to boiling while stirring, re-fluxed over a period of 12 hours after which the dichloro-~;7~

methane was found to have been completely decolorized.
Next, the dichloromethane was removed under reduced pressu-re and the catalyst was dried for ~ hours at 85C under 1.13 millibars.
Yellow pellets containing 0.32 wyt q Rh were obtained.
Catalyst No. 3 5i21 / Rh(dpe)2-/ BF4 4 g activated silicon dioxide (98 O SiO2) which had a diameter of 3 mm, an inner BET-surface area of 280 m2/g and a pore volume of n.9s ml/g was added to 193 mg (2û.1 mg Rh) compound of the formula / Rh(dpe)2_/BF4 dissolved in 100 ml dichloromethane under N2. The yellow suspension was heated to boiling while stirring and refluxed over a period of 12 hours after which the dichloromethane was found to have been completely decolorized. Next, the dichlorornethane was.
removed under reduced pressure and the catalyst.was dried for 8 hours at 85~C under 1.13 millibars.
Yellow pellet~s containing 0.47 wgt ' Rh were obtained.
Catalyst No. 4 A1203 ~ r Rh(dpb)(CO)C1 72 5.3 9 activated aluminum oxide balls (99 ~O A1203) which had a diameter of 3 mm, an inner BET-surface area of 125 m2/g and a pore volume of 0.9 ml/g were added to 29 mg (5.04 mg Rh) compound of the formula / Rh(dpe)(CO)Cl_72 (melting point - 182~C; prepared from 1,4-bis-(diphenylphos-phine)butane and dichlorotetracarbonyldirhodium; cf. A.R.
Sanger, 0. Chem. Soc. Dalton Trans (1977)j 120) dissolved in 50 ml dichloromethane, under N2. The yellow suspens~.on was heated to boiling while stirring and refluxed over a period of 1~ hours after which the dichloromethane solvent was found to have been completely decolorized. Next, the dichloromethane was removed under reduced pressure and the catalyst was dried for 8 hours at 85C under 1.13 milli-bars.
Yellow pellets containing 0.08 wgt O Rh were obtained.
Catalyst No. 5 Cr2~3 / Rh(dpe)2_/ BF4 6.3 9 activated chromium/aluminum oxide cylinders (5.29 9 A1203 + 1.01 9 Cr203) with the dimensions of 4 x 4 mm and with an inner BET-surface area of 68 m2/g were added to 200 mg (20.9 mg Rh) compound of the formula ~ Rh(dpe)2_78F4 dissolved in 100 ml dichloromethane, under Nz. The green suspension was heated to boiling while stirring and reflu-xed over a period of 24 hours after which the dichlorome-thane was found to have been completely decolorized. Next, the dichloromethane was removed under reduced pressure and the catalys-t was dried for 8 hours at 85C under 1.13 mil-libars. Green pellets containing 0.3 wgt ~O Rh were obtain-ed.
Catalyst No. 6 A1203 ] / Rh(tetraphos I)_/ PF6 3.5 9 activated aluminum oxide balls (99 O A1203) which had a diameter of 3 mm, an inner BFT-surface area of 125 m2/g and a pore volume of û.9 ml/g were added to 100 ml (11 mg Rh) compound of the formula ~ Rh(tetraphos-I)_/+PF6 (melting point = 314C; prepared from (P03)3RhCl and tetra-phos-I; cf. R.B. King et al., Inorg. Chem. Vol. 10 (1971), 7~

page 1851 et seq) dissolved in 50 ml dichloromethane, under N2. The yellow suspension was heated to boiling while stirring and refluxed over a period of 16 hcurs after which the dichloromethane was found to have been completely deco-lorized. Next, the dichloromethane W25 removed under redu-ced pressure and the catalyst was dried for 8 hours at 85C
under 1.13 millibars.
Yellow pellets containing 0.3 wgt ~O Rh were obtained Catalyst No. 7 _ ~ Rh(dpe)2_/ BF4 _ r ~r(dpe)(CQ)4_/
~ g activated aluminum oxide balls (99 ~O A1203) which had a diameter of 3 mm, an inner BET-surface area of 125 m2/g and a pore volume of 0.9 ml/g were added to 100 mg (10.4 rng Rh) compound of the formula ~ Rh(dpe)2_7BF4 and 100 mg (9.25 mg Cr) compound of the Formula ~ Cr(dpe)(C0)4 7 (prepared as described by J. Chatt et al., J. Chem. Soc.
(London) 1961, pages 4980 et seq.) dissolved in 100 ml di-chloromethane, under N2. The yellow suspension was heated to boiling while stirring and refluxed over a period of 12 hours after which the dichloromethane was found to have been completely decolorized. Next, the dichloromethane was rernoved under reduced pressure and the catalyst was dried for 8 hours at 85C under 1.13 millibars. Yellow pellets containing 0.31 wgt O Rh and 0.28 wgt O Cr were obtained.
Catalyst No. 8 / Rh(dpe)2_/~BFe4 NaI

~;'7~

0.1 y sodium iodide dissolved in 30 ml acetone wasadded while stirring to 3 9 activated aluminum oxide balls (99 6 A1203) which had a diameter of 3 mm, an inner BET
surface area of 125 m2/g and a pore volume of 0.9 ml/g, and the whole was heated to boiling, and refluxed over a period of ~8 hours. Next, the solvent was removed and the catalyst balls were dried for 8 hours at 85~C under 1.13 millibars.
The rhodium was applied as described hereinabove For catalyst No. 2 Yellow pellets containing û.31 wgt O Rh and 3.12 wgt 6 NaI were obtained.
Catalyst No. 9 123 ] / Rh(dpen~2_ 7 C104e 10Q mg (10.3 mg Rh) compound of the formula / Rh(dpen) C104 (prepared as described by W.A. Fordyce et al., Inorg.
Chem. 1982, 2i, pages 1455-61) dissolved in 100 ml dichlo-romethane was added under N2 to 3 g activated a1uminum oxi-de balls (99 6 A1203) which had a diameter of 3 mm, an in-ner BET-surface area oF 125 m2/g and a pore volume of 0.9 ml/g. The light yellow suspension was heated to boiling and reflu~ed over a period of 12 hours after which the solvent was found to have been completely decolorized. Next, the solvent was removed under reduced pressure and the catalyst was dried for 8 hours at 85~C under 1.13 mll1ibars. Yello-wish pelle~s containing 0.33 wgt X Rh were obtained.

Claims (24)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for making monocarboxylic anhydrides of the general formula (RCO)2O by reacting a carboxylic acid ester or dialkylether of the general formulae RCOOR and ROH, respectively, in which R stands for one and the same alkyl radical having from 1-4 carbon atoms, with carbon monoxide in gas phase, in the presence of iodine or bromine or their compounds as a reaction promoter and also in the presence of a carrier-supported catalyst containing noble metal compounds belonging to qroup VIII of the Periodic System, at temperature of 130-400°C and under pressures of 1-150 bars, which comprises: using a carrier-supported catalyst in which the carrier material has a noble metal/chelate-compound formed of the noble metal compound and a chelator containing organonitrogen, organophosphorus, organoarsenic or organosulfur groups applied to it.

2. A process as claimed in claim 1, wherein the carrier material of the carrier-supported catalyst has, in addition, a non noble metal/chelate-compound formed of a non noble metal compound selected from the 6th or 8th subgroup of the Periodic System of the elements and a chelator containing organo-nitrogen, organophosphorus, organoarsenic or organosulfur groups applied to it.

3. A process as claimed in claim 1, wherein the carrier-supported catalyst contains a non noble metal compound selected from the 1st through 3rd principal groups or the 4th through 6th or 8th subgroups of the Periodic System of the elements as an additional promoter.

4. A process as claimed in claim 1, wherein the carrier material in the carrier-supported catalyst has a chelate compound formed of a metal compound and one of the following chelators a) Y-(CH2)n-Y
b) Y-CH=CH-Y
c) 02P-CH=CH=P02 d) 02As-CH=CH-As02 e) 02P-CH2-CH2-P0-CH2-CH2-P0-CH2-CH2-P02 f) 02P-CH2-CH2-P0-CH2-CH2-P02 g) h) P(-CH2CH2-P02)3 i) R1-C??(CH2)n-Y-73 j) k) in which ? stands for C6H5- ;
Y stands for -NR?, an aryl group containing nitrogen, -Pr?2, -AsR?, -SR2 or -SH ;
R1 stands for -H, a C1-C5-alkyl or -C6H5 ;
R2 stands for a C1-C6-alkyl, a C5-C8-cycloalkyl or -C6H5 or C6H5CH2- ;
n stands for 1 through 6 m stands for 0 through 8, and x stands for 1 or 2 applied to it.

5. A process as claimed in claim 4, wherein R2 stands for a C1-C6 alkyl, a C5-C8-cycloalkyl or -C6H5 or C6H5CH2-substituted with halogen, methoxy, ethoxy or a C1-C3-alkyl.

6. A process as claimed in claim 1, wherein the carrier-supported catalyst contains an inorganic oxidic carrier or an active carbon carrier.

7. A process as claimed in claim 1, wherein the carrier-supported catalyst contains 0.01 - 50 wgt % chelate com-pound.

8. A process as claimed in claim 3,wherein the carrier-supported catalyst contains altogether 0.01 - 50 wgt %
chelate compound and non noble metal compound.

9. A process as claimed in claim 1, wherein the carrier-supported catalyst is used in the form of particles having a size of 1 through 20 mm.

10. A carrier-supported catalyst for making monocarboxylic anhydrides by subjecting a suitable ester or ether to a carbonylation reaction, in which the carrier has a noble metal/chelate-compound formed of a noble metal compound selected from the 8th subgroup of the Periodic System of the elements and a chelator containing organonitrogen, organophosphorus, organoarsenic or organosulfur groups applied to it.

11. A carrier-supported catalyst as claimed in claim 10, in which the carrier has, in addition, a non noble metal/chelate-compound formed of a non noble metal compound selected from the 6th or 8th subgroup of the Periodic System of the elements and a chelator containing organonitrogen, organophosphorus, organoarsenic or organosulfur groups applied to it.

12. A carrier-supported catalyst as claimed in claim 10 containing a non noble metal compound selected from the 1st through 3rd principal groups or the 4th through 6th or 8th subgroups of the Periodic System of the elements as an additional promoter.

13. A carrier-supported catalyst as claimed in claim 10, in which the carrier has a chelate compound formed of a metal compound and one of the following chelators.

a) Y-(CH2)n-Y

b) Y-CH=CH-Y

c) ?2P-CH=CH-P?2 d) ?2As-CH=CH-As?2 e) ?2p-CH2-CH2-P?-CH2-CH2-P?-CH2-CH2-P?2 f) ?2P-CH2-CH2-P?-CH2-CH2-P?2 g) h) P(-CH2CH2-P?2)3 i) R1-C[-(CH2)n-Y]3 j) k) in which ? stands for C6H5-;
Y stands for -NR?, an aryl group containing nitrogen, -PR?, -AsR?, -SR2 or -SH;
R1 stands for -H, a C1-C5-alkyl or -C6H5;
R2 stands for a C1-C6-alkyl, a C5-C8-cycloalkyl or -C6H5 or C6H5CH2-;
n stands for 1 through 6, preferably 1-4;
m stands for 0 through 8, preferably 0-3, and x stands for 1 or 2 applied to it.

14. A carrier-supported catalyst as claimed in claim 13, in which R2 stands for a C1-C6-alkyl, a C5-C8-cycloalkyl or -C6H5 or C6H5CH2- substituted with halogen, methoxy-, ethoxy or a C1-C3-alkyl.

15. A carrier-supported catalyst as claimed in claim 10, containing an inorganic oxidic carrier or active carbon carrier.

16. A carrier supported catalyst as claimed in claim 10, containing 0.01 - 50 wgt % chelate compound.

17. A carrier-supported catalyst as claimed in claim 12, containing altogether 0.01 - 50 wgt % chelate compound and non noble metal compound.

18. A carrier-supported catalyst as claimed in claim 10, having the following formula:
carrier? [Rh((C6H5)2P-CH2CH2-P(C6H5)2)2]C1

19. A carrier-supported catalyst as claimed in claim 10, having the following formula:

carrier? [((C6H5)2P-CH2-CH2-P(C6H5)2)2]BF4

20. A carrier-supported catalyst as claimed in claim 10, having the following formula:
carrier? [Rh((C6H5)2P-CH2)4-P(C6H5)2)(CO)C1]2

21. A carrier-supported catalyst as claimed in claim 10, having the following formula:
carrier ? [RH((C6H5)2PCH2CH2P(C6H5)CH2CH2P(C6H5)CH2CH2P
(C6H5)2)]PF6

22. A carrier-supported catalyst as claimed in claim 10, having the following formula:
[Rh((C6H5)2P-CH2-CH2P(C6H5)2)2]BF4 carrier ?
[Cr(C6H5)2P-CH2-CH2-P((C6H5)2(CO)4]

23. A carrier-supported catalyst as claimed in claim 10, having the following formula:
[Rh((C6H5)2P-CH2-CH2-P(C2H5)2)2]BF4 carrier ?
NaI

24. A carrier-supported catalyst as claimed in claim 10, having the following formula:
carrier ? [Rh((C6H5)2P-CH=CH-P(C6H5)2)2]C104