21. 22. 23. 24.

H. E. Simmons, T. L. Cairness, S. A. Vladuchich, and C. M. Hoiness, Organic Reactions, Vol. 20, Wiley, New York (1973), p. i. D. Seyferth, Accounts Chem. Res., 5, 65 (1972). O. M. Nefedov, A. I. D'yachenko, and A. Ya. Shteinshneider, Izv. Akad. Nauk SSSR. Ser. Khim., p. 320 (1975). J. L. W. Pohlmann, F. E. Brinkmann, G. Tesi and R. E. Daradio, Z. Naturforsch., 20b___, 5

(1965). 25. 26.

27.

M. D. Rausch, G. A. Moser, and C. F. Meade, J. Organomet. Chem., 51, 1 (1973). H. Heaney and J. H. Jablonsky, J. Chem. Soc. C, p. 1895 (1968); J. D. Cook and B. J. Wakesfield, J. Organomet. Chem., 13, 15 (1968); R. L. dePasguale and C. Tamborski, ibid., 13, 173 (1968); S. C. Cohen, F. L. N. Reddy, D. M. Roe, A. D. Tomlinson, and A. J. Massey, ibid., 14, 241 (1968); D. H. Roe and A. G. Masey, ibid., 213___,547 (1970); C. F. Smith, G. D. Moore, and C. Tamborski, ibid., 42, 257 (1972). O. M. Nefedov and A. I. D'yachenko, Izv. Akad. Nauk SSSR Ser. Khim., p. 1378 (1977).

CARBONYLATION OF OLEFINS IN THE PRESENCE OF SUPPORTED PALLADIUM CATALYSTS A. L. Lapidus, S. D. Pirozhkov, A. R. Sharipova, and K. V. Puzitskii

UDC 542o97:547.313:546.262.3-31

The carbonylation of olefins with carbon monoxide, giving carboxylic acids or their esters in a single step, is catalyzed by Group VIII metal complexes in solution [I]. In view of the difficulty of separating these catalysts from the reaction products, the use of heterogeneous catalysts for carrying out this process is of considerable interest [2-5]. In the presence of previously suggested catalysts, however, the reaction only proceeds under severe conditions (325~ 700 atm) and is accompanied by severe corrosion of the apparatus [6]. We have studied the catalytic activity of Pd catalysts supported on carriers with different structures in respect of the carbonylation of ethylene, propylene, and l-hexene. A catalyst containing 5% Pd on BAU-grade carbon is highly active and selective in the case of propylene carbonylation (Table i). Carbonylation was effected in CH3COOH using HI or C3H71 as promoter. In most cases, the C3H 6 conversion reached 97-100% and the yield of by-products (Propyl acetate, propyl n-butyrate, and propyl isobutyrate) was not more than 10%. Increasing the temperature from I00 to 200~ has no significant effect on the C3H 6 conversion but increases the reaction rate appreciably, as evidenced by the fact that the reaction time was reduced from 9 h at 100~ to 2.5 h at 200~ At the same time, the selectivity of the catalyst for butyric acid formation was reduced from i00 to 90%. When n-C3HTI is used as promotor instead of HI, the C3H 6 conversion and the selectivity for butyric acid remain practically unchanged, but in the case of i-C3HTI the C3H6 conversion and the butyric acid content of the product are appreciably reduced. The ratio of iso- to n-butyric acid ranges from 1.0 to 1.36 and is practically independent of the conditions employed. In the case of the carbonylation of l-hexene (Table 2) the main products are s-methylcaproic acid and enanthic acid in a ratio of 1:5. As in the case of C3H6, the l-hexene conversion reaches 100% under optimum conditions. In this case, however, changing the CO pressure has a greater effect on the olefin conversion and the product yields than in the case of propylene. Thus, increasing the pressure from 25 to 85 arm increases the l-hexene conversion by a factor of more than i0. It is known that synthetic H-mordenite has high acid stability [7], so we may expect this zeolite not to be decomposed by the reaction products under the conditions used for carbonylating propylene to produce butyric acids, so that it may be used as a component of a Pd-zeolite catalyst. For comparison, we also tested a Pd/O.8CaNaY catalyst. Both Pd-zeolite catalysts are highly active with respect to the carbonylation of C3H6, giving conversions o~ N. D. Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 371-376, February, 1979. Original article submitted September30, 1977.

0568-5230/79/2802-0343507.50

9 1979 Plenum Publishing Corporation

343

TABLE I. Carbonylation of Propylene on 5% Pd/C Catalyst [Pinit = 100 atm; CO : C3H 6 = 2:3 (molar); in CH3COOH; HI promotor]

I CslI~ [.. Reaction products. ~ ]Ratio of " [eonver-,[is~ n ' . ]butyric I[Pr~ f/so-]pr~ InPrTpyl- [iso.to n_ [butyric

T, oc :ime,

t00 120 150 2OO 150 150 150

9,0 6,5 4,0 2,5 4,0 5,0 5,0

98,0 99,0 ioo,O iOO,O 99.0 * loolo $ 91,7.*

54,0 I 51,0 50,4 45,0 ! 46,7 i 53,4 4i,0

46,0 44,2 42,0 45,0 46,7 39,0 36,1

&

5,4 8,9 6,6t 5,4 t4,8

t,17 l,t5 t,20 1,00 t,00 t,36 i,t4

t7o

1,t

6

5,i

* In C_=HsCOOH. t Propyl propionatc. SPromoter n- CsHTL ** Promoter i- CsHTL

TABLE 2. Carbonylation of l-Hexene on 5% Pd/C Catalyst (170~ in CH3COOH , HI promotor)

c~ I

pressuz~,

Time, h

atm

25 50 60 85 t20

4,5 4,0 2,5 2,0 2,0

l~oduct~,~lT-1-Hexene conversion, ce'methyl- enanthic caproic mole acid acid

9,3 46,0 66,6 t00,0 lO0,O

57,7 58,8 52,7 62,3 54,6

42,3 41,2 47,3 37,7 45,4

TABLE 3. Carbonylation of Propylene on Pd-Zeolite Catalysts, [Pinit = i00 atm, 150~ 5 h, CO : C3H 6 = 2 : 3 (molar); in CH3COOH; HI promotor] CsI-~ conversion, mole o]~

isobutyfic acid

97,0 99,9 * 98,5 t 99,9

Reaction products,%

n-butyric

I

acid

47,4 31,2 8,5

[ I

51,7

I

propyl acetate

~a:io of iso-

propyl/so-' propyl nbutyrate butyrate

I% Pd/O,8 CaNaY 36,5 6,5 5,4 59,5 6,8 t~5 85,7 3,8 t,0 1% Pd/HM 40,9 I 6,5 I 0,9

[

[to n-butyric lacid

3,2 t,0 1,0

] I

1,30 0,52 0,t0

-

I

t,26

* Mixture of CHsCOOH and i-CaHTCOOH (3:1). TMixtt~e of CHsCOOH and i-C3HTCOOH (2:1). 97-99% (Table 3). The selectivity for butyric acid formation is high. When isobutyric acid is added to the initial reaction mixture, the ratio of iso- to n-butyric acid in the reaction products, which is 1.1-1.3 in CH3COOH , is reduced to 0.5-0.1. Thus, the selectivity of the reaction can be modified by altering the composition of the initial reaction mixture. Changing the zeolite component of the catalyst has no significant effect on the yield or the composition of the reaction products. However, the Pd-zeolite catalysts break down in the course of the experiments as a result of the action of acids present in the initial reaction mixture and formed during the carbonylation process. According to x-ray diffraction data, the degree of disintegration of the CaNaY and HM zeolites after the experiment was 100%. Palladium complexes supported on SiO2, with a Pd content of 1%, do not have high activity in respect of the reaction of CO with C3H 6 (Table 4). Carbonylation of propylene in

344

TABLE 4. Carbonylation of Propylene on Supported Palladium Complexes [Pinit = i00 atm, 150~ 2.5 h, CO:C3H 6 = 2:3 (molar), in CH3COOH, HI promoter]

CsH~con- ,~

R~acti~ pr~

vemion, mole #o

I n-butyric

[propyl

l acid

lacctate

obutyric

lacid

~ ]

tRatio of i~olto n-butyric I acid I

propyt npropyl butyrate isobutyrate

(CH2)a~(CIt2)20H on Si02 Pd (OAe)2 41,2

I

36,0

I

26,3 132,9 [ 2,4 Pd(OAc)2 on SiOz

2,4

!

t,37

98,8

I

40,t

I

32,0

3,0

I

t,25

12t,0

I

3,9

TABLE 5. Effect of Pd Content of Pd/C Catalysts on Carbonylation of C2H 4 (PC2H4 = 40 arm, PCO = 60 atm, 170~ in C2H5COOH, HBr promoter) Pd content of catalyst, of. 0,I0 0,25 0,50 0,50 * i,O0 i,50 3,50 iO, O03~

Time, h

6,0 4,5 4,0 2,0 3,5 3.0 3~0 3,0

CzH4con- Yield based on C2H4 reacted, mole ~o version. mole t~ C:H~COOH C~H~GOOC~H5 C~HsCOC~H~ 96,3 95,i 95,0 tO0,O 94,2 97,2 96,4 9%0

98,4 .96,8 96,4 95,6 95,3 96,7 92,4 90,7

0,8 1,2 t,0 2,0 0,8 0,2 1,8 2,3

0,8 2,0 2,6 1,3 3,9 3,t 5,8 4,2

9 In CHsCOOH; CzHsI promotor (0.5mole/liter);CH~COOC2H s yield i.i mole %. t i n CHsCOOH; HI promoter (0.3 mole/liter); CHsCOOCzHs yield 2.8 mole %. The catalyst retained its original activity and selectivity in ten successive experimenr.~' the presence of catalysts containing Pd(OCOCH3) 2 in CH3COOH results in the formation of up to 30-40% of the propyl esters of acetic, butyric, and isobutyric acids. In the presence of Pd/C and Pd-zeolite catalysts, the acetate and propionate ester content was not more than 2-5%. Thus, the presence of acetate groups in the catalyst increases its selectivity with respect to the formation of carboxylate esters. Only resinous products are obtained when the reaction is carried out under analogous conditions using a catalyst comprising (CH2) 3NHCS2PdOAc on SiO 2.

I

N (CzHs) 3

When e t h y l e n e i s c a r b o n y l a t e d i n t h e p r e s e n c e o f Pd c a t a l y s t s b o n and i n t h e p r e s e n c e o f h a l o g e n - c o n t a i n i n g p r o m o t e r s ( H I , HBr, duct is propionic acid. At t h e same t i m e , s m a l l a m o u n t s o f e t h y l ketone are also formed. Increasing t h e Pd c o n t e n t b y a f a c t o r o f reduces the reaction time by a factor of two (Table 5). Further from 1.5 to 10% has little effect on the reaction rate.

s u p p o r t e d on a c t i v e c a r and C 2 H 5 I ) , t h e m a i n p r o propionate and d i e t h y l 15, f r o m 0 . 1 t o 1.5%, increase of the Pd content

It should be noted that the Pd catalysts have high stability. The activity and selectivity of a 10% Pd/C catalyst remains unchanged after ten successive experiments. It can be seen from the data in Table 6 that the C2H 4 conversion and the yields of the main reaction products remain practically constant over long test periods, but the reaction rate decreases. The C2H 4 conversion reaches 99.5% and the selectivity reaches 97-98%. The time required for absorption of CO and C2H 4 by the reaction mixture in the tenth experiment is 2.7 times longer than in the first. The carbonylation of olefins probably proceeds via intermediate formation of Pd complexes. Palladium supported on active carbon is evidently chemically bonded to the support, which has a high surface area. Part of the Pd supported on the carbon goes into solution, with the result that the metal content of the support decreases, and this gradually increases 345

T A B L E 6. Repeated Use of 0.5% Pd/C Catalyst (PC2H4 = 55 atm, PCO = 55 atm, 215~ in CH3C00H , HBr promoter) Reaction time,

h

9

C~H4.con-

Vemion. mole~o

2,0 * 2,5 3,0 3,5 3,5 4,0 4,5 4,0 4,5 5,5

99,9 99,1 99,6 98,0 99,5 99,6 99,4 99,5 99,1 95,1

a$o

on

2 a reacte,

me

%

C2H~COOH

CH~COOC2H5

C:HsCOOC2H5

C:HsCOC:Hs

95,9 95,5 96,9 96,3 97,8 97,6 95,6 96,7 95,6 95,4

0,6 1,t 0,9 0,6 0,4 0,8 0,5 1,7 2,2 3,3

0,4 0,6 0,4 0,5 t,5 0,4 3,0 0,8

3,t 2,8 t,8 2,6 0,3 t,2 t,0 O,S 1,2 0,1

1,0

1,2

* i 8 0 o.

TABLE 7. Carbonylation of C2H 4 on 0.25% Pd/C Catalyst at Different Pressures (170~ in C2H5COOH , HBr promoter) PC2H~

PCO

C2H 4 con =

Yield based on CzH4 reacted, mole r

,vemion, mole

10,0 20,0 40,0 50,0

C2HsCOOC:H~ C2}IsCOC211s

C~HsCOOH

arm

t5,0 30,0 60,0 75,0

80,4 90,5 95,3 85,3

92,4 . 94,4 91,6 95,9

i ~ t

2,5 t,0 3,3

7,6 3,0 6,4 0,8

the time required to achieve total ethylene conversion. When the total pressure of C2H 4 and CO is increased, while the ratio of the components is kept constant (Table 7), the C2H 4 conversion passes through a maximum corresponding to a total pressure of I00 atm, while the yields of the main products do not undergo any significant change. When the reaction is carried out in CH3COOH at 250~ and an initial total pressure of i00 arm in the presence of 5% Pd/C and with a C2H4:CO:H20 molar ratio of 1:1.5:1.5, total C2H ~ conversion is achieved in 2 h, giving an equimolar mixture of propionic anhydride and the mixed anhydride of acetic and propionic acid. No anhydride is formed when the reaction is carried out in C2HsCOOH under analogous conditions. Since the carbon and zeolites themselves are inactive in the reaction being investigated, we can assume that Pd or a compound of Pd is responsible for the catalytic activity. The process is affected considerably, however, by the nature of the support used, the structure of the promoter introduced into the reaction zone, and the solvent. The Pd/C catalysts have high activity, stability and selectivity, and HBr, HI, and C2H5I are active promoters. The best of the solvents used for C2H 4 carbonylation is propionic a c i d . The selectivity is reduced in acetic acid due to ethyl acetate formation. We may presume that the carbonylation of olefins in the presence of the studied Pd catalysts takes place on the catalyst surface or in solution, into which part of the palladium probably passes, by one and the same mechanism analogous to the scheme proposed in [8, 9], which includes the following steps: i) alkyl halide formation CH2 = C H 2 + H X - ~ C 2 H s X w h e r e X = Br o r

I

2) o x i d a t i v e

addition

of alkyl

to the

catalyst

(PdL(CO)n} CO I

C~HsX ~ PdL(CO)n ~ C~Hs--Pd--X L

L where L is

346

a ligand

(support)

and n = 1-3

3) insertion of carbon monoxide

t~o

co

I

co

I

C~H~--Pd--X -+ C2HsCO--Pd--X L I L L 4) n u c l e o p h i l i c a t t a c k by w a t e r on t h e complex, w i t h r e g e n e r a t i o n evolution of propionic acid cO [

of the catalyst

and

H~O

C2HsCO--Pd--X -----> C2H~COOH@ HPdL(C0)X 1

l

L

HX + PdL(CO)n

The Pd i n z e o l i t e c a t a l y s t s i s r e a d i l y r e d u c e d i n an H2 a t m o s p h e r e a t ~20~ [10 ], so we may e x p e c t t h a t t h e Pd i n t h e z e o l i t e s u s e d by us w i l l a l s o be r e d u c e d i n t h e CO atmosphere under the conditions studied. In a c c o r d a n c e w i t h t h e method o f p r e p a r a t i o n , t h e p a l ladium i n t h e Pd/C c a t a l y s t s i s z e r o - v a l e n t . EXPERIMENTAL The experiments were carried out in rotating glass-lined steel autoclaves with capacities of 0.15 and 0.25 liter. The autoclaves were placed in an electrically heated furnace. The experiments were continued until the pressure ceased to drop, The promoter concentration was 0.75 mole/liter. Gaseous reaction products were analyzed by Hempel absorption and by means of an LKhM-8MD chromatograph with a thermal-conductivity detector at 60~ (4 m x 2 mm column packed with 2% aqualane on alumina gel). Mixtures of H 2 and CO were analyzed using the same chromatograph at 25~ (combined column with the same diameter, packed with Porapak Q for 4 m and with alumina gel for 4 m); the carrier gas was He. Liquid reaction products were analyzed using an LKhM-8MD chromatograph with a flame-ionization detector (2.5 m x 3 n~n column packed with 10% polyethylene glycol adipate on Chromosorb G); the carrier gas was He. Methyl butyl ketone was used as internal standard. The Pd/C catalysts were prepared as described in [ii]. In the synthetic CaNaY and H-mordenite zeolites, each containing 16% of binder (A1203) , the Pd was incorporated by ion exchange using an aqueous solution of Pd(NH3)~C12. The Si02/AI203 ratio was 4 for CaNaY and I0 for H-mordenite. The catalysts comprising a palladium complex on a support were prepared as described in [12]. The olefin:water ratio was 1:1-1.5 (molar) during carbonylation. Practically no formation of CO 2 and H 2 from the CO and H20 was observed. The authors wish to thank Yu. E. Ermakov and B. N. Kuznetsov for the samples of palladium complexes supported on SiO2. CONCLUSIONS I. Catalysts comprising palladium on carbon or zeolites, with a low Pd content (0.251%), are active and selective in respect of the carbonylation of ethylene, propylene, and l-hexene to form carboxylic acids. 2.

Catalysts comprising palladium on carbon are suitable for repeated use.

LITERATURE CITED i.

J.

F. K n i f t o n , J . Org. Chem., 41, 2885 (1976); U. S. P a t e n t No. 3821265 (1974); U.S. No. 3887595 (1975); U.S. P a t e n t No. 3944604 (1976). U.S. P a t e n t No. 1924769 (1933); U.S. P a t e n t No. 1924767 ( 1 9 3 3 ) ; Chem. A b s t r . , 11, 3193 (1933). U.S. Patent No. 1924765 (1933); Chem. Abstr., 11, 3193 (1933). U.S. Patent No. 1924763 (1933); Chem. Abstr., IT, 3193 (1933). U.S. Patent No. 1924764 (1933); Chem. Abstr., 2__7, 5340 (1933). U.S. Patent No. 2089903 (1937); Chem. Abstr., 3-1, 7069 (1937). D. W. Breck, Zeolite Molecular Sieves: Structure, Chemistry, and Use, Wiley-lnterscience (1974). J. F. Roth, J. H. Craddock, A. Hershman, and E. Paulik, Chem. Technol., 600 (1971). J. K. S t i l l e and K. S. J. Lau, J. Am. Chem. S,c., 98, 5841 (1976). A. L. Lapidus, V. V. Mal'tsev, E. S. Shpiro, G. V. Ant.shin, V. I . Garanin, and Kh. M. Minachev, I z v . Akad. Nauk SSSR, S e r . Khim., 2 4 5 4 . ( 1 9 7 7 ) . Patent

2. 3.

4. 5. 6. 7. .

9. 10.

347

Ii. 12.

N. D. Zelinskii, Collected Works [in Russian], Vol. 3, Izd. AN SSSR, Moscow-Leningrad (1955), p. 271. V. A. Semikolenov, V. A. Likholyubov, and Yu, I. Ermakov, Proceedings of the All-Union Conference on Synthesis and Catalytic Properties of Transition-Metal Complexes Immobilized on Supports [in Russian], Novosibirsk (1977), pp. 39 and 43.

ACTIVITY OF RhNaX CATALYSTS PROMOTED BY TRANSITION-METAL OXIDES IN THE CARBONYLATION OF METHANOL WITH CARBON MONOXIDE AT ATMOSPHERIC PRESSURE B. K. Nefedov, R. V. Dzhaparidze, O. G. Mamaev, and N. S. Sergeeva

UDC 542.97:547.261:546.262.3-31

The formation of methyl acetate from methanol and carbon monoxide is effectively catalyzed on NaX zeolite containing 0.25-1% of rhodium [1,2]. Zeolites containing other transition metals do not have this activity [3]. When the Rh content of the zeolite is <0.25%, the rate of CH3COOCH 3 formation is increased but the formation of CH3OCH 3 as by-product is simultaneously accelerated [2]. Thus, at a rhodium content of 0.1-0.15%, the target product and by-product are formed in equal amounts [4]. In the present work, with the object of developing catalysts with a low rhodium content, we have studied the effect of Cr, Mn, Fe, Co, Ni, and Cu oxides on the activity and selectivity of the Rh form of NaX zeolite. Incorporation of Cr, Mn, Fe, Co, Ni, and Cu oxides in an amount of 0.05-0.2% in catalysts containing 0.1% Rh increases their selectivity for CH3COOCH 3 formation (Table I). In the case of Ni, Fe, and Co oxides, the activity is also increased, i.e., the optimum reaction temperature is reduced. The productivity of such catalysts (255-355 g methyl acetate/g Rh-h) is 12-18 times that of Rh/C [5]. To find the optimum conditions under which these catalysts can be used for carbonylating methanol with CO, we investigated the effect of temperature, the amount of oxide promoter, the contact time, and the amount of methyl iodide on the progress of the reaction, and we also investigated the kinetics of the reaction. For the catalysts investigated, the curve of CH3COOCH 3 formation rate* versus temperature over a range of 160-280~ passes through a maximum (Fig. i). The highest rates are achieved under the following conditions (promoter, temperature, rate in moles of CH3COOCH 3 per g of Rh per hour): no promoter, 230~ 3.5; Fe203, 210~ 5.3; NiO, 230~ 3.8; CuO, 240~ 3.8; CoO, 220-250~ 3.5; Cr203, 260~ 3.5; MnO2, 260~ 2.9. The promoting activity increases in the order Fe203> Cr203 > CoO > NiO > CuO > Mn02 at temperatures up to 220~ and in the order Fe203 > NiO > CuO > CoO > Cr203 > MnO2 at temperatures of 220-250~ Incorporation of 0.05% of Cu or Fe oxide into a 0.1% RhNaX catalyst reduces the yield of dimethyl ether and increases the rate of CH3COOCH 3 formation (Table 2 ) . Increasing the oxide content to 0.25% has very little effect on the yield of methyl acetate and its formation rate. Similar results were obtained with catalysts promoted by oxides of Co, Cr, Ni, and Mn. These data indicate that the oxide promoter should be incorporated in the catalyst in an amount of 0.05-0.2%. The conversion of CH3OH to CH3COOCH 3 in the presence of 0.1% RhNaX catalysts promoted with the oxides of Fe (at 210~ and of Cu and Co (at 250~ increases in direct proportion to the contact time T over a range of 4-35 sec (Fig. 2). As in the case of the unpromoted catalyst, methanol is not carbonylated in the absence of CH3I. The CH3OH conversion and CH3COOCH 3 yield increase continuously with increasing CH3I concentration, reaching values of 90-92 and 50% respectively for catalysts promoted *The CH3COOCH3 formation rate was determined as the average over an operating cycle of the catalyst which did not alter in activity for more than I00 h. -N . D . Zelinskii Institute of Organic Chemistry, Academy of Sciences of the USSR, Moscow. Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 2, pp. 376-381, February, 1979. Original article submitted July 6, 1977. 348

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