1674
Ind. Eng. Chem. Res. 1994,33, 1674-1679
Kinetics of Primary Reactions of Vapor-Phase Methanol Carbonylation on Sn-Ni/C Catalyst Tuan-Chi Liu' and Shwu-Jer Chiu Department of Chemical Engineering, National Taiwan Institute of Technology, 43, Keelung Road Section 4, Taipei 106, Taiwan, R.O.C.
Vapor-phase carbonylation of methanol (MeOH) was investigated under atmospheric pressure. A novel heterogeneous Sn-Ni/C catalyst was utilized for the reaction. Experiments were designed with the elimination of mass-transfer resistances t o extract reaction data. The data of primary reactions in the carbonylation were collected via a differential tubular reactor. Feed composition to the reactor was varied to examine the effect of partial pressures of reactants on the reaction rate. The carbonylation was conducted a t several temperatures for the determination of activation energies. Power law rate models were employed to express the conversion of methanol and the yields of methyl acetate and dimethyl ether. Adequate results were obtained with the models to represent the experimental data.
Introduction Carbonylation of methanol to methyl acetate and acetic acid has been widely investigated because of the industrial significance of this reaction. The reaction was explored under both atmospheric (Scurrell and Howe, 1981) and pressurized conditions (Fujimoto et al., 1983). Homogeneous and heterogeneous catalysts were both utilized for the carbonylation. Methyl iodide (MeI) was found to be essential in the cases. The rate-determining step of the reaction was discovered to be the cleavageof the C-I bond of methyl iodide. Roth et al. (1971) examined methanol carbonylation applying a homogeneous Rh catalyst. The rate of methanol conversion was found to be of zero order in both methanol and carbon monoxide, and first order in methyl iodide. Identical results were released for the reaction on a solid supported rhodium complex catalyst (Robinson et al., 1972). These findings yield the conclusion that a similar mechanism is expected for a homogeneous catalyst and for the catalyst's anchored counterpart. The same reaction orders were reported from an independent investigation of the carbonylation, employing a supported nickel boride catalyst and under a pressurized condition (Chen and Ling, 1991). The reaction orders appear to be independent of the catalyst type and the reaction conditions. However, other experiments produced varied results. Liu and Wang (1992) utilized a zeolite supported rhodium catalyst for the reaction and found the orders to be 1.0,0.3, and 0.1 with respect to methyl iodide, methanol, and carbon monoxide, respectively. Omata et al. (1985),who examined the carbonylation on Rh/C, reported that the orders are 0.7,0.6, and 0.3 with respect to methyl iodide, methanol, and carbon monoxide. The orders appear affected by the type of catalyst applied to the reaction. Carbonylation of methanol consists of several parallel and consecutive reactions. Methyl acetate is the desired product formed directly from the reactants, methanol, and carbon monoxide. Dimethyl ether, a byproduct, is formed from a side reaction requiring only methanol as the reactant. Both methyl acetate and dimethyl ether are formed directly from the reactants and are considered primary products. The reactions leading to formation of primary products are the primary reactions. Acetic acid, which is formed from the hydrolysis of methyl acetate
* To whom all correspondence should be addressed. OSSS-5SS5/94/2633-l674$04.50/0
(Fujimoto et al., 19821,is considered a secondary product. Methane, which can be formed in various reaction routes, is considered both a primary and a secondary product (Omata et al., 1985). A complete kinetic analysis involving the products is complicate. The analysis can be markedly simplified via the usage of a differential reactor. The reactor generates data without interference from products; thus both secondary and reversible reactions can be neglected. Another advantage of a differential reactor involves the diminution of temperature and concentration gradients in the reactor. The diminution avoids complications caused by the gradients and can significantly simplify the kinetic analysis. The usage of a heterogeneous Sn-Ni/C catalyst in this investigation is a consequence of a recent finding that Sn has a promoting effect for Ni/C in methanol carbonylation (Liu and Chiu, 1994). Kinetic analysis of a vapor-phase methanol carbonylation utilizing this novel catalyst is present in this paper. Pore and external film resistances were eliminated in the reaction experiments. A differential reactor was employed. The primary reaction data are represented by power law models. Parameters of the models were determined from the data by means of linear regression.
Experimental Section Catalyst Preparation. The catalysts were prepared via incipient impregnation. Predetermined quantities of Ni(N0&-6Hz0and SnC1~2Hz0(Merck, GR grade) were dissolved in deionized water. Activated carbon (1023m2/ g, Strem) was then impregnated with the solution to create a slurry. The slurry was then dried in vacuum at 393 K for 12 h. The resulting dried material was then stored in a desiccator. The active Sn-Ni/C catalyst was generated from the dried material via reduction conducted in situ prior to each reaction run; both nickel and tin loadings on the catalyst were 5 wt 5%. Carbonylation. The reaction was carried out at atmospheric pressure in a tubular reactor (0.64-cm o.d., U-shape, Pyrex). The catalyst bed contained a mixture of catalyst (0.4 g) and powdered quartz (0.5 g). The latter was employed to diminish both the gas channeling and the temperature gradient in the bed. Quartz wool was packed on both sides of the bed to minimize scatter of catalyst by the flowing gases. A thermocouple was inserted in the reactor to measure the reaction temperature. 0 1994 American Chemical Society
Ind. Eng. Chem. Res., Vol. 33, No. 7, 1994 1675
F : 0: H: I : J : K: L : M: N: 0: P:
venl1
three-way ball valve ball valve healer tsmpsn(ura conlrollsr
IhsrmocMlpls reaclor
calaly$I bad
GC
sampling valve ulld Imp inlspnlo, 0 : lee R : hsalinp up0 S : nowmeler
P
Figure 1. Schematic flow diagram of methanol earbonylation
A schematic flow diagram of the reaction appears in Figure 1. Each carbonylation experiment was initiated with catalyst reduction performed in situ at 673 K under flowing H1 for 3 h. The temperature of the catalyst bed was then decreased to the desired reaction temperature. Reactants were then continuously fed at the temperature to activate the catalyst. The activation required approximately 3 h (Liu and Chiu, 1994). Kinetic data were not collected until the catalyst was activated. In a typical run, thedatawerecollectedafterthecatalystwasonstream for 4 h. The partial pressures of methanol, carbon monoxide, and methyl iodide in the carbonylation were varied via regulation of reactant flow rates. Methanol and methyl iodide, being liquid at room temperature, were fed by a syringe pump whereas carbon monoxide and argon were fed from gas cylinders. The flow rates of the gases were set by meansof mass-flow controllers. The partial pressure of each reactant in turn was varied while partial pressures of the other two were maintained constant. The independent partial pressure variation was accomplished through usage of argon in the feed, which compensated for variation of a reactant. For example, increased partial pressure of methanol was accompanied by decreased pressure of argon. Hence the total pressure and partial pressuresofmethyliodideandcarbonmonoxidewere kept the same. The conversion of methanol was limited to less than 10% soas toobtainadifferentialmodeofoperation, which furnished the advantage of minimizing interference caused by carbonylation products. Thecomplicated data analysis due to concentration and temperature gradients was also markedly simplified. The effluent gas from the reactor was sampled by an autosampling valve and was immediately analyzed in a gas chromatograph. The chromatograph was equipped with both a flame ionization detector (FID) and a thermal conductivity detector (TCD) connected in series. The sample to be analyzed passed first the TCD and then the FID. Organic compounds were analyzed by means of the FID, water and other permanent gases were detected by means of the TCD. The column utilized in the chromatograph was Porapak Q, 80/100 mesh, 2-m X 0.32-cm
stainless steel. The temperature of the column was maintained initially at 423 K for 10 min; the temperature was then programmed at a ramping rate of 15 K/min until reaching 483 K the latter temperature was maintained for 16mintocompletetheanalysis. Inadequate resolution was discovered among hydrogen, argon, and carbon monoxide on this column; therefore another gas chromatograph was employed to separate these compounds. Thesecondchromatograph wasequipped with aTCDand a Carbosieve SII, 80/100mesh, 2-m X 0.32-em stainless steel column; the temperature of the column in this gas chromatograph was maintained at 323 K throughout the analysis. Methanol conversion ( X A )and yield (Yi)for the reaction are defined as
where FAO = rate of feed of methanol (mol/h), FA= rate ofeffluxofmethanol (mol/h),Fi = rateof effluxof product i (mol/h), N,= number of methyl groups in product i. Chemical Reactions and Models Many reactions proceed during carbnylation of methanol. The reactions form a complicated reaction path network involvingseveral parallel and consecutive routes. Thereactionsmay bereversibleand irreversible,and both reactants and products can participate in various stages. The complicated situation is significantly simplified by means of a differential reactor, which enables collection of kinetic data with a small conversion of methanol. Therefore, reversible reactions and reactions involving producta can be neglected; only primary reactions need be considered in these conditions. The primary reactions in carbonylation of methanol are 2CH,OH
+ CO
-
CH,COOCH,
+ H,O
(3)
1676 Ind. Eng. Chem. Res., Vol. 33, No. 7, 1994 Table 1. Values Adopted for the Weiez-Prater Criterion
item (-rAP.)ota
L
D&
c:
value 5.4 x 1w 2.4 X lo-' 7.2 x lo-' 8.7 X lV
unit mol/(cm3h) cm cm*/h mol/cms
;L 01
0
1
2
3
4
5
6
7
8
9
Time on stream(h)
Figure 2. Stability of catalyst (reaction conditions: T = 503 K, P = 100 P a , feed molar ratio CO/MeOH/MeI/Ar = 10/9/1/5, contact time = 23.7 g-cat-h/mol). c
Two approaches can be adopted to eliminate the gradients. One is the utilization of a small catalyst. The other strategy is applying a low temperature of reaction. The former approach diminishes the concentration and temperature variations between the center and surface of the catalyst. The latter diminishes the rate of the surface reaction more than the rate of transport through the catalyst pores. As a consequence, the overall rate of reaction is shifted toward being controlled by the surface reaction. The significance of pore resistance can be tested by means of two classical methods. The first is to employ catalysts of varied particle sizes (Froment and Bischoff, 1990). This test is inadequate in our investigation because of lack of catalysts of varied sizes. The other method is the utilization of the Weisz-Prater criterion (1954): (5)
3L
8 2
-
0
0.04 0.06 0.08 toto1 molar flow rate(rnol/h)
0.02
Figure 3. Effect of total molar flow rate on methanol conversion (reaction conditions: T = 503 K,P = 100 P a , feed molar ratio CO/ MeOH/MeI/Ar = 10/9/1/5, contact time = 23.7 g-cath/mol).
and 2CH,OH
-
CH,OCH,
+ H20
(4)
Both reactions proceed in the presence of only the chemicalsin the feed. Methyl acetate results directly from methanol and carbon monoxide. The second reaction requires only methanol as the reactant. Methane, which is considered both a primary product and a secondary product, was not detected, probably due to the smallconversion of methanol controlled in this work. The kinetics of formation of methane are hence not discussed.
Results and Discussion Stability of Catalyst. The conversion of methanol on Sn-Ni/C steadily increaseswith the time on stream (Figure 2). The activation process last for about 3 h. The activity of the catalyst reaches a maximum at the end of the activation. No obvious deactivation is observed for the catalyst for at least 5 h after the activation has completed. Data for kinetic examinations are collected with the catalyst on stream for at least 4 h. The data are, therefore, considered as steady-state data. Pore Resistance. The transport resistance within a catalyst particle can markedly affect the rate of reaction. Pore resistance produces both concentration and temperature gradients within a catalyst that distort the rate data to yield erroneous kinetic conclusions. Experiments for kinetics investigation must therefore be designed to eliminate the gradients.
where -rA = rate of reaction of methanol (mol/(h g-cat)), pa = density of catalyst particle (g-cat/cm3),L = catalyst radius (cm),D,A = effective diffusivity of methanol (cm2/ h), C: = concentration of methanol at the catalyst surface (mol/mL), and obs = observed result. The criterion employs information that is readily available. Typical values of Q determined in this investigation are listed in Table 1. The calculated Q based on these values is 5.0 X 106. The significance of Q lies in its magnitude; the presence of limitation of pore diffusion is indicated by Q >> 1. The value Q = 5.0 X 106 clearly indicates that pore resistance is negligible in these experiments. External Film Resistance. The significance of external film resistance was examined. The results are illustrated in Figure 3. The data in this figure were obtained by passing reactants through the catalyst bed at varied rates of feed. The reaction temperature and the contact time were maintained constant during obtaining of these data. Ifthe external film resistance is insignificant, the conversion is expected to be independent of the flow rate. Otherwise, external film resistance is present. External film resistance, as indicated in Figure 3, can be neglected at a rate of flow exceeding 4.7 X le2mol/h. The relative significance of external film resistance and surface reaction toward the overall rate of reaction can also be managed via reaction temperature. Diminishing the reaction temperature decreases the rate of surface reaction more than the rate of transport through the film. As a consequence, decreased reaction temperature leads to a declined influenceof external f i b and shifts the overall reaction toward surface reaction control. The insignificance of external fiim resistance is illustrated in Figure 3 at a flow rate of 4.7 X le2moVh and at a reaction temperature of 503 K. The experiments for kinetic data were therefore performed with a minimum flow rate of 4.7 X mol/h and a maximum reaction temperature of 503 K. The enforcement of the conditions ensured the obtained data were outside the influence of external film resistance.
Ind. Eng. Chem. Res., Vol. 33, No. 7,1994 1677
..1 Feed B:
Table 2. Material Balance for a Typical Carbonylation Run. molar flow rate (pmol/min) compounds feed effluent effluent - feed CHaOH 281.0 267.5 -13.5 CHaI 31.2 31.0 -0.2 co 312.2 306.0 -6.2 CH30CH3 0.6 0.6 CH3COOCH3 6.2 6.2 HzO 6.9 6.9 a Reaction conditions: T = 503 K;P = 100 Wa; contact time = 23.7 g-cat.h/mol; molar ratio of feed CO/MeOH/MeI/Ar = 10/9/1/5. Table 3. Elemental Balance for a Typical Carbonylation Run. molar flow rate (pmol/min) elemente feed effluent effluent/feed C 624.4 624.3 0.9998 H 1217.6 1217.6 1.0000 0 593.2 593.4 1.0003 I 31.2 31.0 0.9936 a Determined based on the data in Table 2.
Material Balance. Table 2 presents the molar flow rates of the feed and the effluent streams of a typical carbonylation run. The conversion of methanol from this run is about 4.8% . The effluent stream contains dimethyl ether, methyl acetate, water, and the unreacted reactants. Acetic acid is not present in the stream. This observation verifies that the acid is not a primary product. Fujimoto et al. (1982)have reported that the acid is a secondary product which is formed through the hydrolysis of methyl acetate. The majority of the products are methyl acetate and water. A small amount of dimethyl ether can also be found in the effluent stream. A careful examination of the data can reveal that the effluent rate of methyl acetate equals the consumption rate of CO. The summation of half of the production rate of methyl acetate and the production rate of dimethyl ether equals the consumption rate of methanol. The production rate of water equals the summation of the production rates of methyl acetate and dimethyl ether. These relations illustrate the reactions involved can be precisely represented by the two reactions shown in eqs 3 and 4. More than 99% of Me1 feed is recovered in the effluent stream as indicated by the data in Table 3. Considering the experimental error involved, this observation can be practically viewed as that Me1 is not consumed in the reaction. The iodide probably acts as a promoter for the catalyst or serves to form intermediates in the reaction and then is regenerated. The elemental balance, calculated on the basis of the data in Table 2, is shown in Table 3. A remarkable closeness between the rates of the feed and the effluent for each element is demonstrated in this table. Effect of Partial Pressures. The effects of contact time on the conversion of methanol for several feed compositions are illustrated in Figure 4. Similar results for the yields of methyl acetate and dimethyl ether are demonstrated in Figures 5 and 6. The rates of methanol conversion under various methanol partial pressures were determined from slopes of the lines in Figure 4. The results are plotted in Figure 7. The relations of the yield rates of methyl acetate and dimethyl ether with methanol partial pressure are present in the same figure according to similar treatments. Increasing methanol partial pressures, in general, increases the reaction rates. The effects of
12
molar ratio,CO/MeOH/Mel/Ar 10/14/1/0 1011 4/1/0 -lo 0:10/9/1/5 0 10/9/1/5 9 r.1015 6/1/8 4
4
8
I
12 16 20 24 28 32 36 40 W/FAo (g-cat.h/mol)
Figure 4. Effect of contact time on methanol conversion (reaction conditions: T = 503 K;P = 100 Wa). 12 11
Feed molar ratio,CO/MeOH/Mel/Ar
/
4
0
8
/
12 16 20 24 28 32 36 40
W/FAO(g-cat.h/mol)
Figure 5. Effect of contact time on methyl acetate yield (reaction conditions: T = 503 K;P = 100 Wa). 2.0,
t Feed molar ratio,CO/MeOH/Mel/Ar
I R
A
5
10
e
08
E
0
4
1015 6/1/8 4
8
12 16 20 24 28 32 36 40
W/FAO(g-cat.h/mol)
Figure 6. Effect of contact time on dimethyl ether yield (reaction conditions: T = 503 K P = 100 kPa).
methanol partial pressure on the rate of methanol conversion and on that of methyl acetate yield are nearly the same. The yield rate of dimethyl ether is markedlyaffected by the partial pressure of methanol . The effects of partial pressures of methyl iodide and carbon monoxide on the rates were also obtained according to procedures similar to that to obtain Figure 7. The results are shown in Figures 8 and 9. Effect of Reaction Temperature. The temperature effects on the rates of conversion of methanol or yields of methyl acetate and dimethyl ether appear in Figure 10. The rate of yield of dimethyl ether is apparently less affected by the reaction temperature than the rates of methanol and methyl acetate. Activation energies of the reactions were determined from the rate data obtained at various reaction temperatures.
1678 Ind. Eng. Chem. Res., Vol. 33, No. 7, 1994 10.00
5b
32-
0
8
x- 1.00
7
7
5:
L?
3: 2-
3
5 1
0.10
e
7: 0:AcOMe
5:
320.01 I 10
J
2
3
18
100
5
partial pressure of methanol(kPa)
Figure 7. Effect of partial pressure of methanol on reaction rates (reaction conditione: T = 603 K,P = 100 P a , PM.I=4 kPa, Pco = 40 kPa, contact time = 23.7 g-cat.h/mol).
19
20 21 1 TT( l/K),xlOOO
22
23
Figure 10. Arrhenius plot of reaction rates in the carbonylation of methanol (reaction conditione: P = 100 kPa, feed molar ratio CO/ MeOH/MeI/Ar = 10/9/1/5, contact time = 23.7 g-cat-Wmol).
II
k = ko exp(-EIRT)
(7)
where ko = frequency factor, E = activation energy, R = gas constant, and T = reaction temperature (K). The resulting equation, after substituting eq 7 into eq 6, can be transformed into Ink] = ln[kol - E/R[l/Z'I
n ln[Pcol (8)
0:AcOMe
0.01 I
I
I
2
3
5
10
partial pressure of methyl iodide(kPa)
Figure 8. Effect of partial pressure of methyl iodide on reaction rates (reaction conditions: T = 603 K,P = 100 P a , P M ~=H 34-38 kPa, Pco = 40 P a , contact time = 23.7 gcat-Wmol).
I
5L 0
8
32-
5- 1 0 0 =
-
-
=
5:
e
5: 32-
7 32 2E1 0 1 0 -
+ q ln[P,,,I + m ln[PAl+
rn :MeOH
0 :AcOMe A :DME
001 10 2 3 5 100 partial pressure of carbon rnonoxide(kPa)
Figure 9. Effect of partial pressure of carbon monoxide on reaction HkPa, rates (reaction conditions: T = 603K,P = 100kPa, P ~ = 40 &I = 4 P a , contact time = 23.7 g-cath/mol).
Rate Model. The rate of conversion of methanol and the rates of productions of methyl acetate and dimethyl ether were represented by power law models of the following form:
where r = reaction rate (mol/(h g-cat)), k = rate constant (mol/(hg-cat kpaqimin)), PMel = partial pressure of methyl iodide (Wa), PA = partial pressure of methanol (kPa), Pco = partial pressure of carbon monoxide (kPa), and q, m,n = reaction orders. Furthermore, the rate constant is expressed in terms of reaction temperature according to Arrhenius relation:
The parameters, ko, E, q, rn, and n were determined by means of linear regression. Original data for the regression are presented in Figures 7 and 10. The parameters determined from the regression are listed in Table 4. The relative magnitudes of the corresponding parameters among the reactions were utilized to alter the selectivity. The production of methyl acetate, for example, has the smallest value of q among the reactions (Table 4); hence decreased partial pressure of methyl iodide leads to increased selectivity of methyl acetate. In general, the selectivityof methyl acetate was enhanced with decreased partial pressures of both methanol and methyl iodide. The selectivity can be further increased with an increased partial pressure of CO and reaction temperature. The reaction orders and activation energies obtained from various investigations for the rate of formation of methyl acetate are listed in Table 5. The same reaction orders were observed with Rh/Y, Rh/support, and B-Ni/C catalysts. However, the observation cannot be extended to the other catalysts which have varied reaction orders. The order of reaction and the activation energy of the formation of methyl acetate are, therefore, affected by the type of catalyst. The parameters of Sn-Ni/C differ from those of other catalysts. Distinct catalytic properties are possessed by the novel catalyst can be demonstrated by this observation. The adequacy of the models was examined by plotting predicted rates according to the model versua experimental rates (Figure 11). The points exactly lie on the diagonal line for a completelyprecise model. The models developed in this investigation are accurate to represent the data as indicated by this figure. Conclusion
Power law models were developed for primary reactions of carbonylation of methanol on a novel Sn-Ni/C catalyst. Sufficient accuracy was obtained with the models to determine the rates of yields of methyl acetate and dimethyl ether. The kinetic parameters for the carbo-
Ind. Eng. Chem. Res., Vol. 33, No. 7,1994 Table 4. Estimated Parameters of the Power Law Model. parameters
ko E (kJ/mol) q m n 33.9 1.6 1.2 0.6 5.50 X 1W
rate
methanol conversion methyl acetate formation 1.08 X 103 dimethyl ether formation 7.40 X 10-'2
37.6 4.8
1.4 1.1 0.6 3.3 2.7 0.1
Model: r = ko exp(-E/RT)PM~~pAmPco". Table 5. Parameters of the Rate of Methyl Acetate Formation. catalvst Dressure Eb Q m n reference Rh/polymeF atmospheric 14.6 1.2 0.5 1.0 Shimazu et al. (1987) Rh/X atmospheric 63.6 1.0 0.3 0.1 Liu and Wang (1992) Rh/Y atmospheric 56.5 1.0 0 0 Takahashi et al. (1979) Rh/C pressurized 45.2 0.7 0.6 0.3 Omata et al. (1985) Rh/supportd pressurized 1.0 0 0 Robinson et al. (1972) Ni/C pressurized 90.4 0.1 0.6 0.7 Omata et al. (1985) 1.0 0 0 ChenandLing(1991) B-Ni/C pressurized Sn-Ni/C atmospheric 37.6 1.4 1.1 0.6 this investigation ~
Model: r = ko exp(-E/RT)Dphi&PAmPcon. Unit: kJ/mol. Polymer: chelate resin of polyethylenimine type. BPL grade activated carbon anchored Rh complex.
8 1000,
z
-B
5
-E
l 0 0 r
x.
2 m
2
c
B
1
,I
*MeOH OAcOMe MDME
2 -
5 -
,c
a 2 3 010: u al 5 -
E
3:
-
2 - 0 0 12 001 2 010 100 ~1000 rate by experiment(mol/g-cat h),x1000
Figure 11. Predicted rates according to model and experimental rates.
nylation of methanol utilizing Sn-Ni/C catalyst were distinct from those of other catalysts. Significant lower activation energy could be found with Sn-Ni/C than with most other catalysts. The reaction order with respect to methyl iodide was found to be 1.4, showing the novel catalyst depended heavily on the iodide to promote the
1679
carbonylation. The reaction orders with respect to methanol and CO were respectively found to be 1.1and 0.6 on Sn-Ni/C.
Acknowledgment We thank the National Science Council of the Republic of China for support (under Contract No. NSC 83-0402E011-005). Literature Cited Chen, Y. Z.; Ling, K. S. Carbonylation of Methanol over Supported Nickel Boride Catalysts. J. Chin. Znst. Chem. Eng. 1991,22,103108. Froment, G. F.; Bischoff, K. B. Chemical Reactor Analysis and Design, 2nd ed.; Wiley: Singapore, 1990; pp 167. Fujimoto, K.; Shikada, T.; Omata, K.; Tominaga, H. Vapor Phase Carbonylationof Methanolwith Supported Nickel Metal Catalysts. Znd. Eng. Chem. Prod. Res. Dev. 1982,21,429-432. Fujimoto, K.; Shikada, T.; Omata, K.; Tominaga, H. Vapor Phase Carbonylation of Organic Compounds over Supported Transition Metal Catalysts. 2. Synthesis of Acetic Acid and Methyl Acetate from Methanol with Nickel-Active Carbon Catalyst. Znd. Eng. Chem. Rod. Res. Dev. 1983,22,436-439. Liu, T. C.; Wang, C. H. Methanol Carbonylation on Molecular-Sieve Supported Catalyst. J. Chin. Znst. Chem. Eng. 1992,23,9&102. Liu, T. C.; Chiu, S. J. Promoting Effect of Tin on Ni/C Catalyst for Methanol Carbonylation. Znd. Eng. Chem. Res. 1994,33,488-492. Omata, K.; Fujimoto, T.; Shikada, T.; Tominaga, H. Vapor Phase Carbonylation of Organic Compounds over Supported TransitionMetal Catalyst. 3. Kinetic Analysis of Methanol Carbonylation with Nickel-Active Carbon Catalyst. Znd. Eng. Chem. Prod. Res. Dev. 1985,24,234-239. Robinson, K. K.; Hershman, A.; Craddock, J. H. Kinetics of the Catalytic Vapor Phase Carbonylation of Methanol to Acetic Acid. J. Catal. 1972,27,389-396. Roth, J. F.; Craddock, J. H.; Hershman, A.; Paulik, F. E. Low Pressure Process for Acetic Acid via Carbonylation of Methanol. Chem. Technol. 1971,23,600-605. Scurrell, M. S.; Howe, R. F. Highly Active Rhodium-Zeolite Catalyst for Methanol Carbonylation. J. Mol. Catal. 1980, 7, 535-537. Shimazu, S.; Ishibashi, Y.; Miura, M.; Uematsu, T. Methanol Carbonylation Catalyzed by Polymer-Supported Rhodium Complexes. Appl. Catal. 1987,35, 279-288. Takahashi, N.; Orikasa, Y.; Yashima, T. Kinetics and Mechanism of Methanol Carbonylation over Rh-Y Zeolite. J. Catal. 1979, 59, 61-66. Received for review November 29, 1993 Revised manuscript received March 10, 1994 Accepted April 21,1994. Abstract publishedin Advance ACS Abstracts, June 1,1994.
