I n d . Eng. Chem. Res. 1990,29, 29-34
PACis thus the double integral (AII-3) which accounts for all 7 between 0 and At. Evaluation of the integrals allowed formulation of PAcin terms of the individual transition probabilities, PAB = 1- e-kmAtand PBC = 1 - e - k B C A t , as shown in
Expression AII-4 limits to PAc = PBCat k A B = m and PAC = PABa t k B C = a. When km = kBC = k , the expression for PAc is calculated by direct integration of expression AII-3 or by applying 1'H'bpital's rule to expression AII-4:
PAC= 1 - e-kAt - kAte-kAt = PAB + (1 - PAB) log (1 - PAB) (AII-5) Registry No. PolyVGE, 123837-36-5; lignin, 9005-53-2; acetovanillone, 498-02-2; vinylguaiacol, 7784-99-8.
Literature Cited DeGennes, P. G. Reptation of a Polymer Chain in the Presence of Fixed Obstacles. J . Chem. Phys. 1971, 55, 572. Domburg, G. E.; Rossinskaya, G.; Sergeeva, V. N. Study of Thermal Stability of P-Ether Bonds in Lignin and its Models. Thermal Anal.-Proc. 4th ICTA 1974,2, 211. Freudenberg, K.; Neish, A. C. Constitution and Biosynthesis of Lignin; Springer Verlag: New York, 1968. Froment, G. F.; Bischoff, K. B. Chemical Reactor Analysis and Design; John Wiley & Sons: New York, 1979. Gillespie, D. T. A General Method for Numerically Simulating the Stochastic Time Evolution of Coupled Chemical Reactions. J . Comp. Phys. 1976,22, 403.
29
Gillespie, D. T. Exact Stochastic Simulation of Coupled Chemical Reactions. J. Phys. Chem. 1977a, 81 (25), 2340. Gillespie, D. T. Concerning the Validity of the Stochastic Approach to Chemical Kinetics. J . Stat. Phys. 1977b, 16 (3), 311. Goodman, A. W.; Ratti, J. S. Finite Mathematics with Applications; Macmillan Publishing Co, Inc.: New York, 1975. Kinsinger, J. B. Polymer Conformation as a Markov Chain Problem. In Markov Chains and Monte Carlo Calculations in Polymer Science; Lowry, G. G., Ed.; Marcel Dekker: New York, 1970. Lopez-Serrano, F.; Castro, J. M.; Macosko, C. W.; Tirell, M. Recursive Approach to Copolymerization Statistics. Polymer 1980,21 (March), 263. Lowry, G. G. Molecular Weight Distributions. In Markov Chains and Monte Carlo Calculations in Polymer Science; Lowry, G. G., Ed.; Marcel Dekker: New York, 1970. McDermott, J. B. Chemical and Stochastic Modelling of Complex Reactions: A Lignin Depolymerization Example. Ph.D. Dissertation, University of Delaware, 1986. McDermott, J. B.; Klein, M. T.; Obst, J. R. Chemical Modelling in the Deduction of Process Concepts: A Proposed Novel Process for Lignin Liquefaction. Ind. Eng. Chem. Process Des. Deu. 1986, 25 (4), 885. McQuarrie, D. A. Methuen's Review Series in Applied Probability. Volume 8 Stochastic Approach to Chemical Kinetics; Methuen & Co. LTD: London, 1967. Neurock, M.; Libanati, C.; Klein, M. T. Modelling Asphaltene Reaction Pathways: Intrinsic Chemistry. AIChE Symp. Ser. 1989, in press. Price, F. P. Copolymer Composition and Tacticity. In Markov Chains and Monte Carlo Calculations in Polymer Science; Lowry, G. G., Ed.; Marcel Dekker: New York, 1970. Schaad, L. J. Monte Carlo Integration of Rate Equations. J . Am. Chem. SOC.1963,85, 3588. Turner, J. S. Discrete Simulation Methods for Chemical Kinetics. J . Phys. Chem. 1977,81 (25), 2379. Windwer, S. Polymer Conformation and the Excluded-Volume Problem. In Markov Chains and Monte Carlo Calculations in Polymer Science; Lowry, G. G., Ed.; Marcel Dekker: New York, 1970.
Received f o r review March 2, 1989 Accepted September 12, 1989
Alkylation of Phenol with 1-Dodecene and Diisobutylene in the Presence of a Cation Exchanger as the Catalyst Ajit A. Patwardhan and Man Mohan Sharma* Department of Chemical Technology, University of Bombay, Matunga, Bombay 400 019, India
The alkylation of phenol with 1-dodecene and diisobutylene was carried out in the presence of strong cation-exchange resins such as Amberlyst 15, Amberlyst XN1010, monodisperse K2661, and Filtrol 24 clay. T h e alkylation of phenol with 1-dodecene was studied in the temperature range 55-120 " C and with diisobutylene in the range 50-100 O C . The catalyst loading was varied from 2.5% to 10% (w/w), and the mole ratio of phenol t o the alkylating agent was varied from 1:l to 4:l to assess the yield of the dialkylated phenol. The operating conditions were optimized to maximize the yield of dodecylphenol and p-tert-octylphenol. The alkylation of phenol with 1-dodecene and diisobutylene to give dodecylphenol and p-tert-octylphenol is generally carried out with homogeneous Bronsted or Lewis acid catalysts. However, this process suffers from the drawbacks of separation of the soluble catalyst from the reaction mixture, disposal of the waste liquors, etc. Thus, the use of heterogeneous catalysts offers clear advantages over homogeneous catalysts since no washing of the catalyst is required. Dodecylphenol and p-tert-octylphenol are widely used in the chemical industry for the manufacture of lube oil additives, nonionic detergents, epoxy resins, oil-soluble 0888-5885/90/2629-0029$02.50/0
phenol-formaldehyde resins, etc. This work was undertaken to make a systematic study of the above reactions in the presence of cation-exchange resins such as Amberlyst 15, Amberlyst XN1010, monodisperse K2661, and Filtrol 24 clay and to map suitable conditions so as to maximize the yield of of dodecylphenol in the case of 1dodecene and p-tert-octylphenol in the case of diisobutylene. The alkylation of phenol with olefin has been widely studied using different catalysts such as sulfuric acid, aluminum chloride, Si02-A1203, activated clay, etc. However, limited information is available in the literature 0 1990 American Chemical Society
30 Ind, Eng. Chem. Res., Vol. 29, No. 1, 1990 Table I. Physical Properties of Cation Exchangers Amberlyst Amberlyst physical property 15 XNlOlO K2661 shape beads beads beads bead size distribution, 0.5 h 0.6 mm (min 90%) internal surface area, 55 540 b m2/g weight capacity, meq 4.5 3.3 1.35n H+/g
porosity, vol 7 0 temp stability
36
120
50 120
60 130
Filtrol 24 granular b 358 0.3 37 b
"In accordance with DIN standards. *Data not available
on the use of cation exchangers as catalysts, and most of the information is in the form of patents. Tsvetkov et al. (1972) have reported that the reaction between phenol and higher olefins at 130 "C in the presence of KU-2 cation exchanger can provide a 90.5% yield of monoalkylphenol. In this paper, the term yield of dodecylphenol is defined as the ratio of the amount of 1-dodecene converted to dodecylphenol to the total amount of 1-dodecene consumed in the reaction. Shkaraputa et al. (1973) have developed a mathematical model for the alkylation of phenol and a-olefins using KU-2 cation exchanger as the catalyst. Melikova et al. (1974) have obtained 44% conversion of a-olefin by carrying out the reaction at 60 "C for 1.5 h. They have also observed that, by increasing the reaction temperature from 60 to 120 O C , the conversion of a-olefin increased from 44% to 92% in the same period of time. A mathematical model has been developed by Kiedik et al. (1979) to describe the alkylation of phenol with diisobutylene in the temperature range 60-110 "C, at a phenol to diisobutylene mole ratio of 1-5:1, and at a reaction time of 0.5-9.5 h. It has been claimed by Society der Produits Chemiques du Sidobresinnova (1974) that the alkylation of phenol with diisobutylene in the presence of cationexchange resins containing 10-20% water can selectively produce p-tert-octylphenol, whereas p-tert-butylphenol is obtained when an anhydrous exchanger is used.
Experimental Section Catalyst. The cation exchangers used were Amberlyst 15 and Amberlyst XNlOlO obtained from Rohm and Haas Co., Philadelphia; monodisperse K2661 was obtained from Bayer, W. Germany. The clay catalyst used was Filtrol 24 obtained from Filtrol, Los Angeles. The catalysts were initially washed with acetone to remove any impurity present on the external surface of the catalyst and dehydrated under vacuum (1-2 mm Hg) at 100 "C for 4 h. The physical properties of the ion exchangers used are given in Table I. Apparatus and Procedure. All the experiments were carried out in a mechanically agitated contactor having an internal diameter of 0.05 m and height of 0.095 m and equipped with four baffles. A six-bladed glass-disk turbine impeller was used for agitation. The reaction was carried out at the desired temperature by placing the reactor in the constant-temperature bath. Phenol in the molten form was taken in the reactor to which the required amount of catalyst was added, and the mixture was stirred for some time (about 300 s) so as to allow the catalyst to swell completely; subsequently, the required amount of olefin was added. Analysis. The analysis of the reaction mixture was done on a Netel chromatograph equipped with a flame ionization detector and connected to a LCI-100 integrator. A stainless steel column, 3 m long and internal diameter of 2 mm, packed with 10% OV-17 on Chromosorb L, was used for the analysis of the reaction mixture. The injector
0
I
0.5
I 1.0 Rracfion time Ihr
I
1
1.5
2.0
1
Figure 1. Effect of moisture content on the rate of alkylation of phenol with 1-dodecene. Reaction conditions: temperature, 100 "C; initial concentration of phenol, 5.13 kmol/m3; concentration of 1dodecene, 2.56 kmol/m3; catalyst loading, 5% (w/w) (Amberlyst 15).
and the detector temperatures were 300 "C. The oven temperature was held at 100 "C for 120 s and then increased to 300 "C by programming at the rate of 0.25 "C/s. The nitrogen flow rate was 0.5 cm3/s.
Results and Discussion The alkylation of phenol with 1-dodecene was carried out in the temperature range 55-120 "C and that with diisobutylene in the range 50-100 "C. The mole ratio of phenol to the alkylating agent was varied from 1:l to 4:l to assess the effect on the yield of the dialkylated phenols. The catalyst loading was varied from 2.5% to 10% (w/w). The results reported in this paper were obtained with the fresh catalysts. However, further experiments carried out with the used catalyst showed no decrease in the catalytic activity of the resin. The term used catalyst refers to the catalyst previously used for the same reaction. There was no deactivation of the catalyst either with the progress of the reaction or repetitive use of the catalyst. Effect of Catalyst Loading. The rate of the reaction was found to vary linearly with an increase in the catalyst loading from 2.5% to 10% (w/w). With an increase in the catalyst loading, the number of sulfonic acid groups increases, resulting in an increase in the concentration of carbonium ion formed per unit time, which in turn increases the rate of reaction. Effect of Speed of Agitation. There was no effect of the speed of agitation in the range 12-40 rev/s on the rate of reaction. Further, values of the apparent rate constants were well below the calculated values of the external mass-transfer coefficient based on the correlation developed by Levins and Glastonburry (1972). Thus, it can be concluded that in the range of stirrer speeds employed the external mass-transfer resistance was absent. Effect of Particle Size. For a specified catalyst loading, there was no effect of the variation in the particle size from 0.3 to 0.6 mm on the rate of the reaction. This suggests that the diffusional resistance of the reactants in the macropores of the ion-exchange resin is not important. Effect of Water. The main aim of this study was to find the effect of water on the rate of reaction and on the selectivity with respect to monoalkylphenol. The presence of water in the reactants or in the catalyst (Amberlyst 15) had a detrimental effect on the rate of alkylation of phenol
Ind. Eng. Chem. Res., Vol. 29, No. 1, 1990 31 H,C-ICH,Ir-CH
1IH'
1-dodrcene
=CHI
,
H,C-lCHI19-CH-CH,
-
0-6 H I CH, -,1 CHI
6-
d o d r c y l phenyl e t h e r
C11HZS P
0
dodecyl phenol
Figure 3. Reaction network in the alkylation of phenol with 1-dodecene catalyzed by cation-exchange resins.
Reaction time ( h r
I
Figure 2. Concentration profiles for various components in the alkylation of phenol with 1-dodecene. Reaction conditions: temperature, 55 O C ; initial concentration of phenol, 5.13 kmol/m3; concentration of 1-dodecene, 2.56 kmol/m3; catalyst loading, 5% (w/w) (Amberlyst 15).
with 1-dodecene (Figure l), but no adverse effect on the yield of alkylphenol was observed at the same level of conversion of the olefin under otherwise identical conditions. Similar deactivation due to water was also observed in the case of other cation-exchange resin catalysts. The drop in the catalytic activity of the cation-exchange resins in the presence of water is typical of the reactions that are catalyzed by undissociated sulfonic acid groups. The cause of this deactivation was described by Zundel (1969) with the help of infrared spectroscopic studies. He observed that each water molecule is bound to three sulfonic acid groups, which results in a decrease in the catalytic activity of the resin but not to the equivalent extent. It is difficult to quantitatively account for the deactivation due to water, and this requries further detailed study. Kinetic Model. The overall kinetics of the process consists of a combination of series and parallel reactions, making the kinetic expression describing the overall process somewhat complicated. But this can be simplified in a realistic way under the following conditions. (i) The mole ratio of phenol to the alkylating agent is greater than one. (ii) The level of conversion of the olefin is below 80%. (iii) The reaction temperature is above 100 "C so as to avoid the formation of alkylphenyl ether in the alkylation of phenol with 1-dodecene. In the case of alkylation of phenol with diisobutylene, the reaction temperature should be above 70 "C, so as to suppress the dimerization of diisobutylene and should be below 100 "C for avoiding the formation of p-tert-butylphenol. Under these conditions, the formation of monoalkylphenol is the predominant reaction, and for this step, the rate of the reaction can be given as dCP - - - kOCcCACBexp -dt
( RET)
(1)
The rate equation proposed above matches well (within 5-7%) with the experimentally obtained results in the alkylation of phenol with 1-dodecene over the entire range of operating conditions (i.e., reaction temperatures from 55 to 120 OC and a mole ratio of phenol to 1-dodecenefrom 1:l to 4:l).
3l
80
l Reaction t i m e ( h r l
Figure 4. Effect of temperature on the rate of alkylation of phenol with 1-dodecene. Reaction conditions: initial concentration of phenol, 5.13 kmol/m3; concentration of 1-dodecene, 2.56 kmol/m3; catalyst loading, 5% (w/w) (Amberlyst 15).
In the case of the alkylation of phenol with diisobutylene, the rate equation proposed above showed about 10-15% variation from the observed values over the entire range of operating conditions, i.e., the reaction temperatures from 50 to 90 "C and mole ratio of phenol to diisobutylene from 1:l to 4:l. This was due to the parallel reaction of dimerization of diisobutylene in the presence of cation-exchange resins as the catalysts, and it was not possible to suppress the dimerization of diisobutylene completely. Alkylation of Phenol with 1-Dodecene. The concentration profiles for the various components in the reaction mixture are shown in Figure 2. It is clear that the reaction network, as shown in Figure 3, consists of a combination of series and parallel reactions, resulting in the formation of dodecylphenol, dialkylphenol, and alkyl phenyl ether and rearrangement of ether to dodecylphenol. The monoalkylated product was found to be a mixture of many isomers such as 4- and 2-(l-methylundecyl)phenol, (1-ethyldecyl)phenol, and (1-propylnony1)phenol. The isomer distribution was not affected by the reaction time. The gas chromatography analysis indicated the isomerization of 1-dodecene to 2- and 3-dodecene, but special emphasis was not given on the isomerization of the olefin in the presence of cation-exchange resins as the catalyst. The oligomerization of 1-dodecene was not observed even
32 Ind. Eng. Chem. Res., Vol. 29, No. 1, 1990 ~~~~
5.0
-0iirobutyIene +Ambrrlyst
XNlOlO
5.0 70C
-
/
+Octyl
phenol
+Tetra
isobulylrne
+Dioctyl
phenol
4.0-
. n
E
8
-e
3.0
0
C
J
1.0
1.5
2.0
2.0
1.0
Reaction time ( h r l
Figure 5. Effect of different cation exchangers on the rate of alkylation of phenol with l-dodecene. Reaction conditions: temperature, 110 "C; initial concentration of phenol, 5.13 kmol/m3; concentration of 1-dodecene, 2.56 kmol/m3; catalyst loading, 5% (w/w).
under extreme operating conditions, i.e., at 120 "C and 10% (w/w) loading of Amberlyst 15. Effect of Temperature. The effect of temperature on the rate of the reaction is shown in Figure 4. The activation energy for the formation of dodecylphenol was found to be 3.97 X lo4 kJ/kmol in the presence of Amberlyst 15 as the catalyst, whereas in the presence of monodisperse K2661 the activation energy was 4.38 X lo4 kJ/kmol. The activation energies reported in this paper are apparent activation energies. Though lower values of the activation energies were obtained, it was confirmed that the rections are free from mass-transfer limitations. The lower value of the activation energy can be linked to the existence of microgels within the resin where most of the reaction occurs. The variation in the reaction temperature from 55 to 90 "C decreased the yield of alkyl phenyl ether from 3.8% to 1.0% at about 50% conversion of 1-dodecene,and above 100 "C,no ether was detected in the reaction mixture. The variation in the mole ratio of phenol to 1-dodecene from 1:l to 4:l decreased the yield of the dialkylated phenol from 11.8% to 2.4% at about 95% conversion of 1-dodecene. Comparison of the Catalytic Activity of Different Cation Exchangers. The results obtained with different cation exchangers are shown in Figure 5. The comparison of the catalytic activity of different cation exchangers used was done on the basis of the same catalyst loading. The highest reaction rates amongst those tried were obtained with Amberlyst 15. Though the difference in the hydrogen ion capacity of Amberlyst 15 and Amberlyst XNlOlO is not substantial (Table I), Amberlyst 15 showed about 2.25 times more reactivity than Amberlyst XN1010. In the case of Amberlyst 15, due to moderate degree of cross-linking (20% DVB), most of the sulfonic acid groups are in the gel phase, whereas due to higher degree of cross-linking (85% DVB), in the case of Amberlyst XN1010, most of the catalytically active groups are in the surface phase. It is known that sulfonic acid groups in the gel phase are more active than those in the surface phase. This results in a decrease in the catalytic activity of Amberlyst XN1010. In the case of other catalysts, it was difficult to correlate the catalytic activity with the physical properties of the resins used. In general, the catalytic activity of ion-ex-
0 0
0.25
0.75
0.50 Reaction timr l h r
1.00
I
Figure 6. Concentration profiles for various components in the alkylation of phenol with diisobutylene. Reaction conditions: temperature, 50 "C; initial concentration of phenol, 6.13 kmol/m3; concentration of diisobutylene, 3.06 kmol/m3; catalyst loading, 5% (w/w)(Amberlyst 15).
7%
;Ha
H,C-C-CH2-C
I
y":
fHa
=CHt
H,C-C-CH=C-Cy
Oiiiobutvlenr
I
CH a
CHI
2+,4
2 , 4 , 4 trimethyl-1-pentenc
trimethyl-2-pentene
P
/
/
/
/
trtraisobulvlene
H'
\
OH
\
1
OH
OH
T 'DH17
-p
0
t r r t - o c t y l phenol
Figure 7. Reaction network in the alkylation of phenol with diisobutylene catalyzed by cation-exchange resins.
change resin was found to be proportional to the hydrogen ion capacity of the resin as it is directly connected with the rate of formation of carbonium ion and its subsequent addition to phenol. The yield of dodecylphenol was practically the same with all cation exchangers used at the same level of conversion of the olefin. Alkylation of Phenol with Diisobutylene. The concentration profiles for various components in the reaction mixture are shown in Figure 6. The reaction network consists of a combination of series and parallel reactions of the formation of octylphenol, dioctylphenol, and tetraisobutylene, i.e., a dimer of diisobutylene. The reaction network is as shown in Figure 7. In the available literature on the alkylation of phenol with diisobutylene, apparently no information has been provided on the dimerization of diisobutylene catalyzed by ion-exchange resin. However, diisobutylene, in the absence of phenol, is capable of undergoing oligomerization (Higushimuro, 1982). In the presence of acidic catalysts
Ind. Eng. Chem. Res., Vol. 29, No. 1, 1990 33 1
100)
!tol
or 0
I
0.25
I
0.50 Reaction t i m e ( h r )
I
0.75
1.0
Figure 8. Effect of temperature on the rate of alkylation of phenol with diisobutylene. Reaction conditions: initial concentration of phenol, 6.13 kmol/m3; concentration of diisobutylene, 3.06 kmol/m3; catalyst loading, 5% (w/w) (Amberlyst 15).
such as ion exchange resins, diisobutylene showed marked tendency to dimerize. However, there was no evidence of trimerization or tetramerization of diisobutylene. At the beginning, the rate of dimerization was relatively very hgh, and the yield of tetraisobutylene reached as high as 20%. However, with the progress of the reaction, the dimer concentration decreased and at the end of the reaction, it was below 5%. The mono-tert-octylphenol thus formed was a mixture of 0- and p-tert-octylphenol. The ratio of p- to o-octylphenol goes on increasing with the progress of the reaction and with an increase in the reaction temperature. Dimerization of Diisobutylene. The dimerization of diisobutylene in the presence of cation exchangers to give tetraisobutylene was studied separately and was found to be first order with respect to diisobutylene. The presence of water in the catalyst was found to suppress the rate of dimerization. In the case of Filtrol 24 clay dried at 120 "C,the yield of tetraisobutylene, during the alkylation of phenol with diisobutylene (2:l mole ratio of phenol to diisobutylene and 5% (w/w) catalyst loading), was as high as 45%, whereas with Filtrol24 containing 12.5% moisture (as supplied) the yield of dimer was only 6.8%. The alkylation of phenol with tetraisobutylene in the presence of cation exchanger resulted in the formation of octylphenol and not hexadecylphenol as expected. Alkylation of Phenol with Diisobutylene. The alkylation of phenol with diisobutylene was found to be first order with respect to both phenol and diisobutylene. With an increase in the mole ratio of phenol to diisobutylene from 1:l to 4:1, the yield of dioctylphenol dropped from 6.8% to 1.8% a t about 97% conversion of diisobutylene. Effect of Temperature. The effect of temperature on the rate of the reaction is shown in Figure 8. The activation energy was found to be 2.88 X lo4 kJ/kmol in the presence of Amberlyst 15, whereas in the presence of monodisperse K2661 it was 3.72 x 104 kJ/kmol. As already mentioned, in the alkylation of phenol with diisobutylene, the proposed rate equation shows about 10-15% variation from the experimentally obtained values; the activation energy values reported here may have an error of 10%. The alkylation reaction was found to be more susceptible to the variation in the reaction temperature than the dimerization reaction. Hence, higher temperatures are fa-
Reaction t i m r ( h r l
Figure 9. Effect of different cation exchangers on the rate of alkylation of phenol with diisobutylene. Reaction conditions: temperature, 90 "C; initial concentration of phenol, 6.13 kmol/m3; concentration of 1-dodecene, 3.06 kmol/m3; catalyst loading, 5% (w/w).
vorable for improving the yield of tert-octylphenol. Some experiments were carried out a t temperature as high as 120 "C (this is the upper limit for the utility of Amberlyst 15) with semibatch addition of diisobutylene. These experiments resulted in a very low yield of tetraisobutylene and very high yield of p-tert-octylphenol, but small amount of p-tert-butylphenol (3-5%) was also formed. This is due to the depolymerization of diisobutylene in the presence of cation-exchangeresin at higher temperatures and subsequent addition of isobutylene with phenol to give p-tert-butylphenol. Comparison of the Catalytic Activity of Different Cation Exchangers. The rate of alkylation of phenol with diisobutylene in the presence of different cation exchangers is shown in Figure 9. The highest reaction rates were realized with Amberlyst 15 due to its high hydrogen ion capacity, whereas Filtrol24 showed the least reactivity. Though very high reaction rates were realized with Amberlyst 15, the yield of p-tert-octylphenol was about 80%. The best yields of 90% were obtained with monodisperse K2661. The ratio of p- to o-tert-octylphenol was highest in the case of Filtrol24 (-45), but the yield of octylphenol was poor due to the high yield of tetraisobutylene. In the case of monodisperse K2661, the ratio of p- to o-octylphenol was 22.4, whereas in the case of Amberlyst 15 and Amberlyst XNlOlO it was 18.6 and 9.3, respectively. Alkylation of Phenol with Diisobutylene To Give p-tert-Butylphenol. It has been claimed in the literature (Alfs et al., 1983) that the reaction of phenol with diisobutylene with some changes in the operating conditions can be used for the synthesis of p-tert-butylphenol. Hence, an attempt was made to find suitable conditions under which p-tert-butylphenol can be produced in good yields. The experiments were carried out in the presence of cation-exchange resins a t 120 "C (this is the upper limit of the temperature specified) with a semibatch mode of addition of diisobutylene. However, this procedure showed a very low yield of p-tert-butylphenol ( 3 4 % ) . Since Filtrol24 can be used at temperatures higher than 120 "C, an experiment was carried out at 140 "C in the presence of Filtrol24, and semibatch addition of diisobutylene resulted in a 20% yield of p-tert-butylphenol and the rest was tert-octylphenol. This suggests that still higher temperatues and stronger catalysts are required for the se-
I n d . Eng. Chem. Res. 1990, 29, 34-39
34
lective formation of p-tert-butylphenol. Hence, experimenta were carried out at 170 "C in the presence of strong acidic catalysts like sulfuric acid, p-toluenesulfonic acid, and Nafion H (this can be used up to 200 "C) with semibatch addition of diisobutylene. In the case of sulfuric acid ( 2 % loading), the yield of p-tert-butylphenol was very high at about 95%, with p-toluenesulfonic acid, the yield of p-tert-butylphenol was very poor (la%),and Nafion H gave a yield of 85%.
Conclusions The alkylation of phenol with 1-dodecene and diisobutylene can be satisfactorily carried out in the presence of cation-exchange resins as the catalyst. The overall kinetics of the process can be described by the following equation:
In the case of the alkylation of phenol with 1-dodecene, Amberlyst 15 is a better catalyst than the other cation exchangers as higher reaction rates are realized under otherwise identical conditions without affecting the yield of dodecylphenol. For the selective production of dodecylphenol, the reaction temperature should be between 100 to 120 "C and the mole ratio of phenol to 1-dodecene should be greater than one, preferably two. In the case of the alkylation of phenol with diisobutylene, monodisperse K2661 is superior to other cation exchangers as it suppresses the formation of tetraisobutylene and gives a higher yield of para isomer. For the selective manufacture of p-tert-octylphenol, the reaction temperature should be between 90 and 100 "C, and the mole ratio of phenol to diisobutylene should be greater than one. It is possible to produce p-tert-butylphenol in 85% yield from phenol and diisobutylene by conducting the reaction at 170 " C , in the presence of Nafion H as the catalyst.
Acknowledgment A.A.P. is thankful to U.G.C., New Delhi, for awarding him a Senior Research Fellowship for this work.
Nomenclature Cp = concentration of alkylphenol, kmol/m3 CA = concentration of phenol, kmol/m3 CB = concentration of olefin, kmol/m3 C, = concentration of catalyst, % (w/w) ko = frequency factor, m3/(kmol.s) E = activation energy, kJ/kmol R = universal gas constant, 8.23 kJ/(kmol.K) 7' = absolute temperature, K t = reaction time, s Registry No. K 2661,123205-61-8;Amberlyst 15, 9037-24-5; Amberlyst XN 1010, 54991-00-3; Nafion H, 63937-00-8;p-tertbutylphenol, 98-54-4; sulfuric acid, 7664-93-9; dodecylphenol, 27 193-86-8:p-tert-octylphenol, 140-66-9;phenol, 108-95-2;1-dodecene, 112-41-4; isobutylene, 115-11-7. Literature Cited Alfs, H.; Boexkes, W.; Vangermain, E. Ger, Offen, DE 3151,693,1983; Chem. Abstr. 1983, 99, 139496d. Kiedik, M.; Kowalska, E.; Hepter, I. Studies on the alkylation of phenol with diisobutylene in the presence of a cation exchanger as a catalyst. Prtem. Chem. 1979,58, 353-6; Chem. Abstr. 1979, 91, 174944e. Higushimuro, T. Jpn Kokai Tokkyo Koho JP 57, 140729, 1982; Chem. Abstr. 1982, 98, 34211h. Levins, D. M.; Glastonburry, J. R. Application of Kolmogoroff s theory to particle-liquid mass transfer in agitated Vessels. Chem. Eng. SCL.1972, 27, 537-543. Melikova, E. M.; Spirak, R. E.; Bakshi-Zade, A. A. Alkylation of phenol by C9 to C12 fractions in the presence of catalyst KU-2. Azerb. Neft. Kohz. 1974,54,41-44; Chem. Abstr. 1975,83,82384d. Shkaraputa, L. N.; Lediev, R. Ya.; Lebedev, E. V.; Sklyar, V. T.; Manoilo, A. M.; Danilenko, V. V. Mathematical model of the statistics for phenol alkylatin with a-olefins. Khim. Tekhnol. (Kieu).1973, 6, 41-4; Chem. Abstr. 1974, 80, 70466g. Society der Produits Chemiques du Sidobresinnova. Fr. Demande 228,749, 1974; Chem. Abstr. 1975, 83, 9487k. Tsvetkov, 0. N.; Monastyrskii, V. N.; Shirokov, A. N.; Korenev, K. D.; Shiplberg, M. B. Kinetics of alkylation of phenols with higher olefins in the presence of KU-2 cation exchanger. Khim. Tekhnol. Topl. Masel. 1971, 16, 12-16; Chem. Abstr. 1972, 76, 58538s. Zundel, G., Hydration and Intermolecular Interaction Infrared Inuestigations uith Polyelectrolyte membranes; Academic Press; New York, 1969.
Received for review February 13, 1989 Revised manuscript received August 10, 1989 Accepted September 28, 1989
Some Linear Characters in Chemical Reaction Systems Fushan Yin Research Institute of Daily Chemical Industry, T h e Ministry of Light Industry, 14 Wenyuan Street, Taiyuan, Shanri, China
A simple method of matrix transformation is presented t o develop the basic linear characters of a reaction system. As long as the components of the system are determined, its atomic matrix, simple reaction matrix, and stoichiometric restriction matrix are all unique and can be found systematically by elementary matrix transformations. For reaction systems without additional restrictions, the above three matrices show the basic relationships between components and chemical reactions. The simple reaction matrix can be used as a common basis for setting up the reaction schemes. T h e stoichiometric restriction matrix is used to get the best data for calculations of a chemical process. In general, mathematical formulas that describe chemical phenomena may be divided into two types: linear and nonlinear. Though most chemical processes must be described by nonlinear equations, any reaction system has some common linear characters. For instance, a molecular formula is a linear combination of signs of elements. 0888-5885/90/2629-0034$02.50/0
Chemical equations are linear combinations of molecular formulas, the additive properties of many thermodynamic functions, etc. Since Gibbs, investigations of the linear characters of chemical reaction systems have been an interesting subject. However, they are usually limited to finding a set of independent reactions (e.g., Jouguet, 1921; 0 1990 American Chemical Society
