Ind. Eng. Chem. Res. 1989,28, 1261-1264 Smith, T. E.; Bonner, R. F. Vapor-Liquid Equilibrium Still for Partially Miscible Liquids. Ind. Eng. Chem. 1949, 41, 2867. Soave, G. Equilibrium Constant from a Modified Redlich-Kwong Equation of State. Chem. Eng. Sci. 1972, 27, 1197. Soave, G. Application of a Cubic Equation of State to Vapor-Liquid Equilibrium of System Containing Polar Compounds. Int. Chem. Symp. Ser. 1979, 56, 1.2/1.0. Subba, B. V.; Rao, V. C. Isopiestic Binary Vapor-Liquid Equilibria System Chloroform(l)-n-Butano1(2). Chem. Eng. Sci. 1962, 17, 574. Sultanov, R. G.; Skripka, V. G. Solubility of Water in n-Alkanes at Elevated Temperatures and Pressures. Russ. J. Phys. Chem. 1972,46, 1245. Sultanov, R. G.; Skripka, V. G.; Namiot, A. Yu. Moisture Content of Methane at High Temperatures and Pressures. Gazou. Proms t . 1971, 16, 6. Sultanov, R. G.; Skripka, V. G.; Namiot, A. Yu. Solubility of Methane in Water at High Temperatures and Pressures. Gazou. Prom-st. 1972, 17, 6. Thies, M. C.; Paulaitis, M. E. Vapor-Liquid Equilibrium for 1Methylnaphthalene/Methanol Mixtures at Elevated Temperatures and Pressures. J . Chem. Eng. Data 1984, 29, 438.
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Thies, M. C.; Paulaitis, M. E. Vapor-Liquid Equilibrium for 1Naphthol/Methanol and Naphthalene/Methanol Mixtures a t Elevated Temperatures and Pressures. J . Chem. Eng. Data 1986, 31, 23. Verhoeye, L.; Schepper, H. D. The Vapor-Liquid Equilibria of the Binary, Ternary and Quaternary Systems Formed by Acetone, Methanol, Propan-2-01, and Water. Appl. Chem. BiotechnoL 1973, 23, 607. Watanasiri, S.; Thies, M. C.; Paulaitis, M. E. Vapor-Liquid Equilibrium for Quinoline/Methanol and Tetraline/Methanol Mixtures at Elevated Temperatures and Pressures. J . Chem. Eng. Data 1986, 31, 180. Whiting, W. B.; Prausnitz, J. M. Equations of State for Strongly Nonideal Fluid Mixtures: Application of Local Composition Toward Density-Dependent Mixing Rules. Fluid Phase Equilib. 1982, 9, 119. Wilson, G. M. An Expression for the Excess Free Energy of Mixing. J . Am. Chem. SOC.1964,86, 127. Received for review August 9, 1988 Revised manuscript received April 16, 1989 Accepted May 16, 1989
COMMUNICATIONS Isomerization of Methyl Linoleate on Ruthenium(111) Alkoxide Complex: Mathematical Modeling The isomerization of methyl linoleate using ruthenium alkoxide complexes is described. With alcohols, such as isopropyl alcohol (IPA), 1-butanol, 1-hexanol, and 1-octanol, isomerization of double bonds t o produce a conjugated system is the main reaction, with hydrogenation being the side reaction. The latter is formed via the conjugated product. Based on kinetic and infrared spectroscopic data, i t is concluded t h a t the active catalytic species is a ruthenium hydride complex formed by the decomposition of the unstable alkoxide. T h e reaction is mathematically modeled, and the rate parameters are obtained by fitting the simulation to experimental data. These values are compared with data obtained from reactions carried out with supported ruthenium-nickel heterogeneous catalyst. Vegetable oils, like safflower oil, sunflower oil, soybean oil, etc., are rich in linoleic acid, which contains two double bonds a t the C9 and CI2 positions. Isomerization of the double bonds, to produce a conjugated system, is an important reaction in the paint industry. A number of heterogeneous and homogeneous catalyst systems have been reported for the isomerization of methyl linoleate (Cecchi and Ucciani, 1981; Dejarlais and Gast, 1971a,b; Deshpande et al., 1985; Koritala et al., 1970a,b; Ucciani and Cecchi, 1981; Vanderplank et al., 1979). It is found that, among the ruthenium-based catalysts, ruthenium chloride anchored on supports like alumina, silica-alumina, etc., is very active for the isomerization reaction (Narasimhan et al., 1985a). In the present paper, we report a ruthenium(II1) complex as a catalyst for the isomerization of methyl linoleate. The reaction is mathematically modeled, and the rate constants are evaluated and compared with data obtained from supported ruthenium-nickel bimetallic catalysts (Mukesh et al., 1988). Experimental Section Materials. RuC13-XH20obtained from Johnson Mathey was used as the starting material. All the alcohols 0888-5885/89/2628-1261$01.50/0
used were of AR grade. The substrate methyl linoleate (Acme Chemicals Limited, Bombay, India) contained about 90% methyl linoleate. The remaining 10% is methyl oleate and methyl palmitate. In a typical experiment, about 5 mg of RuC13.XH20was dissolved in isopropyl alcohol (IPA), and 10 mL of methyl linoleate was added. The reaction was carried out at the reflux temperature of the solvent under N2atmosphere. The products of the reaction were analyzed by using 6-ft-long EGSS-X column operated a t 200 "C. The products were conjugated methyl linoleate and its geometric isomers and the hydrogenated product methyl oleate and its polymer. Cis-trans and cis-cis isomers are grouped together in the Table I, since the amount of cis-cis isomer formed is quite small. Methyl palmitate was used as an internal standard to compute the polymer content. Results Table I gives the data for the isomerization of methyl linoleate for various alcohols. It may be seen that, with the lower boiling alcohols, the predominant reaction that takes place is double-bond migration to produce conjugated methyl linoleate. The reaction duration is also 0 1989 American Chemical Society
1262 Ind. Eng. Chem. Res., Vol. 28, No. 8, 1989 Table I. Activity Data for t h e Isomerization of Methyl Linoleate" entry templduration solvent % conversion 1 82 OC/17 h IPA 20.4 2 118 OC/3 h 1-butanol 31.3 34.0 3 155 OC/I'/, h 1-hexanol 4 160 "C/ll/, 1-hexanol 60.5 5 155 OC/3 h octanol 39.6 Reaction mixture: 5 mg of RuC13 + 2 mL of solvent
% conjugation
% hydrogenation
% polymer
12.0 26.6 29.5 45.7 35.0
4.2 4.7 4.5 8.5 4.58
3.3 6.2
+ 5 mL of methyl linoleate. Scheme I Formation of Ruthenium Alkoxide and Its Decomposition
u c
0
[AI"
6'0
v
120
2i o
180
TIME ( m i d
CAI* (R=C2Hs, C3H7. etc
)
Figure 1. Kinetics of isomerization reaction at 185 "C (continuous lines, 0.05 wt % RuC13 + 100 w t % octanol; dotted lines, Ru:Ni = 3:1, A1203support, 1.5 wt % catalyst).
relatively long in comparison with that of higher boiling alcohols. However, with high boiling alcohols like hexanol and octanol, the reactions are faster, and in addition to conjugated methyl linoleate, the hydrogenated products and polymer are also formed. (The polymer formed is very little.) Figure 1shows the kinetics of the reaction using octanol as the solvent a t a temperature of 185 O C . The figure is typical of consecutive reaction kinetics. It is clear from the plot that the conjugation reaction takes place first and the conjugated product becomes hydrogenated. The figure also compares the kinetics of the same reaction with ruthenium-nickel catalyst supported on alumina. The conversion in the former case is twice as much as the latter, although the amount of ruthenium used is only half. Polymerization is not observed here and may be due to the presence of solvent and lower catalyst amount. The cis-trans to trans-trans ratio lies in the range 2-4, which is similar to the values obtained with heterogeneous catalysts.
Reaction Mechanism Initially ruthenium(II1) alkoxide is formed. It is known (Bosolo and Pearson, 1977) that ruthenium alkoxide is unstable and undergoes hydrogen elimination to give a metal hydride complex coordinated to the aldehyde or ketone. A compound was isolated after refluxing RuC13.3H20 with ethanol, the IR spectra of which showed two bands-one a t 1910 cm-' corresponding to Ru-H species and one at 1620 cm-' corresponding to Ru O=CHCH3 type species. On the basis of the kinetic data and IR evidence, we propose a hydride addition-elimination mechanism for the isomerization shown in Scheme I. In the scheme, hydrogenation is shown to take place after the conjugation occurs. The scheme shows only that portion of the molecule containing double bonds, for the sake of simplicity.
Isomerization
Hydrogenat ion
CI
Table 11. Estimated Rate Constants (s-') Figure 2a Figure 2b kl 0.00217 0.0165 k2 7.5 x 10-4 0.00168 k3 0.0583 0.267 k4 2.5 X 10" 1.67 X IO4 k5 0.005 0.0258
is mathematically modeled by assuming that the reaction proceeds through a series of basic steps consisting of
kl
[AI
+ [A]*
(1)
[AI+
(2)
- [AI*
ML
[AI*
kl
[MLA]
ML,,
+ [A]*
(3)
+-
Mathematical Model The ruthenium complex catalyzed isomerization process
-% ML, + [A]+ -% MLH2 + [A]
ML,, l/(MLct + ML,,)
(4)
(5)
[A]* and [A]+ are the active ruthenium species as shown in Scheme I. Step 5 in the above model is a combination of all the steps under "hydrogenation" in Scheme I. The generation and consumption of various species with time are represented by the following set of differential equations (for more details in modeling and parameter estimation, refer to Mukesh et al. (1988), which deals with
Ind. Eng. Chem. Res., Vol. 28, No. 8, 1989 1263 Table 111. Estimated Activation Energies, Frequency Factors, and Their 95% Confidence Limits (RuC13 Octanol) activation energy, kJ/mol frequency factor, s-l 2.09 X lo6 f 0.1 X lo6 k, 71.3 f 3.6 k2 28.2 1.01 2.81 f 0.01 3.12 x 105 0.09 x 105 k3 52.46 f 2.2 6097 f 3 k4 66.13 f 3.0 93495 f 5609 k5 57.83 f 4.3
+
*
0
80
40
120
180
200
240
activation energy of the isomerization reaction is found to be of the order of 274 kJ/mol, while the corresponding value with supported ruthenium catalyst is around 400 kJ/mol. This large difference may be due to the following reasons: (a) hydrogen abstraction by the catalyst from the alcohol is more facile than the abstraction from methyl linoleate; (b) the presence of alcohol keeps the catalyst free from deactivation by coke and polymer; also, alcohol reduces the viscosity of the medium; (c) the absence of mass-transfer effects due to dissolution of catalyst in the substrate; and (d) the support may in the heterogeneous case interact with the metal chemically or physically to reduce its activity. The activation energy for the first step is 54 kJ/mol, while the corresponding value with supported ruthenium catalyst is 105 kJ/mol.
280
TIME (minl
0.9
I\ ML ct
0 0
20
60
40
80
min Figure 2. Comparison of model and experiment (0.05 w t 7% RuCl, + 100 w t 7% octanol). (a, top) 140 'C. (b, bottom) 185 OC. Continuous lines, simulation; points, experimental data.
heterogeneous catalytic isomerization). Steps 3 and 4 are similar to the heterogeneous case. dA/dt = (-Rl + R5)/mSo (6) dA*/dt = (R, - R2)/mSo dCML/dt = -R3/CT dC,/dt
= (R3 - R4 - 1/2Rs)/C~
dCtt/dt =
(R4
- 1/2R5)/cT
(7) (9)
Nomenclature [A] = ruthenium trichloride CT = number of moles of reactants, mol C,, = mole fraction of cis-trans isomer CML= mole fraction of nonconjugated methyl linoleate CMLHZ = mole fraction of hydrogenated species C,, = mole fraction of trans-trans isomer ki = rate constant, s-l m = catalyst quantity, g ML = nonconjugated methyl linoleate ML,, = cis-trans isomer ML,, = trans-trans isomer MLHz = monounsaturated species Ri= rates, s-l So = active site concentration per gram of catalyst
(10)
A+=l-A-A* R1 = klAmSo R2 = k2A*mSo
(12) (13) (14)
= klCctCT
R5 = k5(C, + C,,)A+CTmSo
Acknowledgment The authors thank IEL Ltd. for financial support.
(11)
R4
Conclusions Ruthenium alkoxide catayzed isomerization and hydrogenation of methyl linoleate are studied here. The catalyst is prepared in situ by reacting ruthenium trichloride with an alcohol. The reaction is mathematically modeled, and the rate and activation parameters of the model are estimated by fitting the simulation to the observed data. It is found that the reaction is more facile than the supported ruthenium-catalyzed isomerization reaction.
(8)
dCMLH2/dt = R5/CT
R3 = k3CMLA*mSoCT
*
(15) (16) (17)
Parts a and b of Figure 2 compare the experimental data with the model predictions for two different operating conditions. The rate constants obtained by the minimization of the sum of squares of the difference between observed and simulated values are given in Table 11. It is seen that the model predicts the observed behavior well. The rate constants corresponding to steps 3 and 4 at 185 "C are 0.267 and 0.000 17, respectively, while the corresponding values with the heterogeneous catalyst (4% Ru on supports like Al,O,, C, Nay, and MgO) lie in the ranges 0.007-0.017 and 0.0001-0.00025. The activation energies of the five basic steps are estimated assuming Arrhenius-type dependence and listed in Table I11 with their 95% confidence limits. The overall
Registry No. ML, 112-63-0; IPA, 67-63-0; CH3(CHz),0H, 71-36-3; CHp,(CH2)50H, 111-27-3;CH,(CHZ),OH, 111-87-5;RuC13, 10049-08-8.
Literature Cited Bosolo, F.; Pearson, R. G. Mechanism of Inorganic Reactions-A study of metal complexes in solution, 2nd ed.; Wiley Eastern Limited: Chichester, UK, 1977; p 595. Cecchi, G.; Ucciani, E. Precious Metal Catalysis in Fatty Substance Chemistry. (111): Isomerization Reactions of Polyunsaturated Fatty Acids Catalyzed by Supported Precious Metals. Reu. Fr. Corps Gras 1981,28, 257. Dejarlais, W. J.; Gast, L. E. (I) Conjugation of Polyunsaturated Fats: Methyl Linoleate with Tri(Tripheny1phosphino)chlororhodium.
1264
Ind. Eng. Chem. R e s . 1989,28, 1264-1266
J . Am. Oil Chem. SOC. 1971a,48, 21. Dejarlais, W. J.; G a t , L. E. (11)Conjugation of Polyunsaturated Fats: Activity of Some Group VI11 Metal Compounds. J. Am. Oil Chem. SOC.1971b,48, 157. Deshpande, V. M.; Gadkari, R. G.; Narasimhan, C. S.; Mukesh, D. Studies on Kinetics of Catalytic Isomerization of Methyl Lino1985,62, 734. leate. J. Am. Oil Chem. SOC. Koritala, S.; Scholfield, C. R. Selective Hydrogenation with Copper Catalysts: (I) Isolation and Identification of Isomers formed during Hydrogenation of Linoleate. J.Am. Oil Chem. SOC.1970a, 47, 262. Koritala, S.; Butterfield, R. 0.; Dutton, H. I. Selective Hydrogenation with Copper Catalysts: (11) Kinetics. J. Am. Oil Chem. SOC. 1970b,47, 266. Mukesh, D.; Narasimhan, C. S.; Gadkari, R. G.; Deshpande, V. M. Kinetics and Mathematical Modeling of Isomerization of Methyl Linoleate on Ruthenium Catalyst. 1. Conjugation and Hydrogenation. Ind. Eng. Chem. Prod. Res. Dev. 1985,24, 318. Mukesh, D.; Narasimhan, C. S.; Deshpande, V. M.; Ramnarayan, K. Isomerization of Methyl Linoleate on Supported RutheniumNickel Catalyst, Ind. Eng. Chem. Res. 1988,27, 409. Narasimhan, C. S.; Mukesh, D.; Deshpande, V. M.; Gadkari, R. G. A Novel Process for the Production of Conjugated Compounds from Vegetable Oils. IEL Ltd., Indian Patent Appln. 417/ CALl85, 1985.
Narashimhan, S.; Mukesh, D.; Gadkari, R.; Deshpande, V. M. Kinetics and Mathematical Modeling of Isomerization of Methyl Linoleate on Ruthenium Catalyst. 2. Conjugation and Polymerization. Ind. Eng. Chem. Prod. Res. Deu. 1985b,24, 324. Ucciani, E.; Cecchi, G. Process for Catalytic Conjugation of Double Bonds of Polyunsaturated Fatty Compounds. Institute des Corps Grass, Paris, European Patent 81.430013.3, 1981. Vanderplank, P.; Vanoosten, H. J.; Van Dijk, L. Nonmetallic Pd on Resin: A Very Active & Selective Catalyst for Hydrogenation of 1979,56, Diunsaturated Fatty Acid Esters. J. Am. Oil Chem. SOC. 45, 50, 54. Zwicky, J. J.; Gut, G. Kinetic Poisoning and Mass Transfer Effects in Liquid Phase Hydrogenations of Phenolic Compounds over Pd Catalyst. Chem. Eng. Sci. 1978,33(10), 1363.
* To whom all correspondence should be addressed. Doble Mukesh, Chakravarthula S. Narasimhan' Krishnan Ramnarayan, Vinayak M. Deshpande Alchemie Research Centre
P.O. Box 155, Belapur Road Thane 400601, Maharashtra, India Received f o r review July 25, 1988 Accepted April 4,1989
Characteristic Properties of Cutting Fluid Additives Derived from Undecanoic Acid Several derivatives of undecanoic acid were prepared from w-bromoundecanoic acid and w-aminoundecanoic acid, and their characteristic properties as cutting fluid additives were examined. We have found that triethanolamine salts of undecanoic acid having an ethearic substituent in the w-Dosition demonstrated effective rust-inhibiting and antiwear properties in water-based cutting fliids.
A variety of cutting fluids are used for machine operations. Recently, the use of water-based cutting fluids has been of particular interest (Holmes, 1971). The relationship between the properties of water-soluble cutting fluids and the functional groups of various organic additives has not bee reported in detail. The authors have previously shown that epoxides of unsaturated fatty acids have excellent properties as antirust additives for water-soluble cutting fluids (Watanabe et al., 1988). In this work, we examined the antirust properties and lubricity characteristics of various derivatives of undecanoic acid. This communicationwill describe our recent evaluation of these new additives for use in water-soluble cutting fluids.
Experimental Section Preparation of Various Derivatives of Undecanoic Acid. All derivatives were prepared from w-bromoundecanoic acid and w-aminoundecanoic acid by using popular chemical reactions (Fieser and Fieser, 1967). w-Bromoundecanoic acid and w-aminoundecanoic acid used in this work were commercially available from Atochem Co. Ltd. (France). Test Methods. Aqueous solutions of water (100.0 g), triethanolamine (2.0 g), and a carboxylic acid (1.0g) listed in Table I were used. City water in Japan (Chiba and Osaka) was used for all tests. The same results were obtained in the corrosion and lubricity tests as with distilled water. Corrosion tests with cast iron chips were carried out as follows. Two grams of cast iron chips (JIS G 5501, FC-20) which had been washed with benzene was immersed in a sample solution (5 mL) of cutting fluids in a watch glass. The container was covered. After 10 min, the solution was removed by tilting the watch glass. The rust-preventive
effect (the amount of rust on the cast iron chips) was observed after 24 h. A rating of 10 points corresponded to no appearance of rust. Eight points indicated a little appearance of rust. The coefficients of friction were measured a t 25 "C by a pendulum-type oiliness and friction tester (Shinko Engineering Co., Ltd., Tokyo). The special features are as follows: (i) Use of four falls and a pin made of high-quality steel assures the accuracy of test pieces and prevents fitting errors. High testing load is applicable because of the point contact. Formation of boundary oil film is easily made. (ii) The apparatus is free from friction heat because of the pendulum type. (iii) Measuring is simple but accurate and easily reproducible. The main particulars were as follows: test ball, 3/16-in. (4.75-mm) JIS B 1501 high class; test roller pin, diameter X length 2.0 i.d., (+0 to -0.012) X 30 mm; material, SK 3 (JIS G 4401); hardness, HRC 60-66; cycle of pendulum swing, ca. 4 s; maximum pendulum swing, 0.7 rad; test load (maximum hertz/stress), 15000 kg/cm2; temperature of test oil, room temperature to 300 "C (Nihon Junkatsu Gakkai, 1987). Welding loads (kgf-cm-2)were measured on a Soda-type four-ball lubricating oil testing machine a t 200 rpm. This testing machine and friction tester mentioned above have been officially authorized by the Agency of Industrial Science and Technology of Japan as JIS K 2519 and 2219. The main particulars were as follows: test ball diameter, 3/4-in.steel ball (JIS B 1501) (high class, 1-pm tolerance); revolution of spindle, 150-1500 rpm; temperature of test oil, room temperature to 200 "C; hydraulic cylinder diameter, 80 mm; maximum load on the test ball, 1000 kg; pressure of the hydraulic pump, 0-20 kg/cm2; overall dimensions, 1700 mm (diameter) x 650 mm (width) X 1600 mm (height); weight, 450 kg. The machine is obtained
0888-5885f 8912628-1264$01.50/@ Q 1989 American Chemical Society
