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Alkylation of naphthalene using propylene over mesoporous Al-MCM-48 catalysts
Catalysis Communications 8 (2007) 1681–1683 www.elsevier.com/locate/catcom
Alkylation of naphthalene using propylene over mesoporous Al-MCM-48 catalysts Robert Brzozowski b
a,*
, Ajayan Vinu b, Toshiyuki Mori
b
a Industrial Chemistry Research Institute, Rydygiera 8, 01-793 Warsaw, Poland Nano-ionics Materials Group, Fuel Cell Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Received 16 October 2006; received in revised form 30 January 2007; accepted 30 January 2007 Available online 4 February 2007
Abstract Alkylation of naphthalene with propylene over mesoporous Al-MCM-48 catalysts with different silicon to aluminium ratios (nSi/nAl) was tested. The activity of the catalysts increased with decreasing the nSi/nAl ratio. In our experiments alkylation product composition was determined by kinetic and thermodynamic factors. Nevertheless, unfortunately, a high 2,6-diisopropylnaphthalene selectivity was not observed in our catalyst system, that was repetitively described in the literature. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Alkylation; Naphthalene; Diisopropylnaphthalene; Mesoporous material; MCM-48
1. Introduction Diisopropylnaphthalene (DIPN) isomeric mixture is used as a high quality solvent for copying materials [1]. The 2,6-DIPN, isolated from the isomeric mixture, can be used as a raw material for the production of advanced polymers. Therefore, active and stable catalysts for naphthalene alkylation are still searched for, especially those selective towards 2,6-DIPN. Wide pore zeolites are among the best candidates for selective synthesis of 2,6-DIPN. Their pore sizes (0.6– 0.75 nm) are in the range of critical sizes of DIPN isomer molecules (0.66–1 nm [2]), consequently shape selectivity effect can be expected. Wide pore zeolites can distinguish between the slim b,b-DIPN isomers and the bulky a,band a,a-isomers. Among them mordenites revealed to be very selective catalysts. DIPN products obtained over mordenites contained 40–60% of 2,6-DIPN and the 2,6DIPN to 2,7-DIPN mole ratio was much higher than 1 [3–8], i.e. the thermodynamic ratio [2,9]. Dealumination *
Corresponding author. Tel.: +48 22 568 20 20; fax: +48 22 568 21 74. E-mail address: [email protected] (R. Brzozowski).
1566-7367/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2007.01.039
of mordenites developed both their stability and 2,6-DIPN selectivity [7,10]. Further increase of 2,6-DIPN selectivity was achieved by deactivation of the external surface of mordenite with e.g. ceria [11]. A DIPN isomeric mixture contained then even more than 70% of 2,6-DIPN and the 2,6-DIPN/2,7-DIPN ratio was in the range 2–3. Lately, catalytic applications for mesoporous materials such as MCM-41 and MCM-48 in reactions such as alkylation of naphthalene arouse interest. Generally, mesoporous silica materials are inactive in alkylation reactions due to the lack of acid sites owing to their neutral framework and ion-exchange properties. However, e.g. isomorphous substitution of metals such as Al, Ga or Fe into the mesoporous silica walls is critical for the formation of acid sites in the mesoporous channels. Owing to their ordered structure and wide pores (>2 nm), they are promising as active and stable catalysts for naphthalene alkylation to DIPN. There are available literature reports on alkylation of naphthalene with isopropanol over acidic mesoporous catalysts such as Al-MCM-41 and Al-MCM-48 [12–17]. Moreover, an unusually high 2,6-DIPN selectivity and 2,6-DIPN/2,7-DIPN mole ratio in alkylation product
1682
R. Brzozowski et al. / Catalysis Communications 8 (2007) 1681–1683
obtained over mesoporous catalysts are related [14–17]. However, alkylation of naphthalene with propylene as an alkylating agent over mesoporous catalysts has not been reported in the open literature so far. Therefore we carried out preliminary experiments on the above reaction using propylene as an alkylating agent over Al-MCM-48 catalysts with various aluminium contents. 2. Experimental Three Al-MCM-48 samples with various aluminium contents (the numbers in parentheses denote nSi/nAl ratios of the catalysts) were tested in alkylation of naphthalene with propylene. They were prepared according to the methods described elsewhere [17], where the details on their properties can also be found. Alkylation experiments were carried out in a fixed-bed reactor under pressure of 3 MPa, the naphthalene/propylene mole ratio of 1.5 and a feed flow 20 g/gh. Inlet temperature was changed in the range of 150–300 °C, starting from the lowest set point and stabilising reaction conditions for at least 1 h at each temperature. Product samples were collected and analysed by the GC method described elsewhere [18]. 3. Results and discussion Results of naphthalene alkylation with propylene on AlMCM-48 (25) and Al-MCM-48 (50) mesoporous catalysts are presented in Tables 1 and 2. The catalyst sample AlMCM-48 (100) i.e. with the lowest Al loading was almost inactive and lost its trace activity very quickly. Propylene conversion on Al-MCM-48(50) was low and the activity of the catalyst was almost lost very quickly. The highest conversion of only 44% was observed for 250 °C, in spite of shorter time on stream than that usually applied, because 200 °C temperature set point was omitted. The Al-MCM-48 (25) was the most active catalyst and a practically total conversion of propylene was achieved at the reaction temperature of 200 °C. Table 1 Results of alkylation of naphthalene with propylene on Al-MCM-48 catalysts Temperature (°C)
Propylene conversion (%)
Selectivity to (mole%)
2-IPN in IPN (%)
IPN
DIPN
Al-MCM-48(50) 150 3.0 250 44.4 300 14.4
47.4 56.6 52.8
tr.a 16.5 10.2
26.5 33.4 37.9
Al-MCM-48(25) 150 15.3 200 97.9 250 99.2 300 98.6
75.8 52.1 51.4 57.2
4.7 22.0 24.1 28.9
25.8 33.4 44.5 70.0
a
tr. – traces of DIPN were detected.
Isopropylnaphthalene (IPN) and DIPN were the main products of the alkylation of naphthalene with propylene. Other products such as tri- and tetra-isopropylnaphthalenes, alkylnaphthalenes with at least one substituent other than the isopropyl group, propylene oligomers, etc. were also observed. Al-MCM-48 catalysts revealed rather a weak isomerization activity when compared with amorphous aluminosilicate or zeolite catalysts. In the monoalkylated product no more than 70% of 2-IPN was detected (Table 1), whereas under similar alkylation conditions but at lower temperature 85–90% of 2-IPN was formed over amorphous aluminosilicate or zeolites H-beta or HY [19]. Similarly, low isomerization activity was observed in the case of diisopropylnaphthalenes (Table 2). With temperature elevation the distribution of 2,6- and 2,7-isomer in DIPN product increased, whereas that of 1,4-DIPN and 1,5-DIPN decreased. Even at such a high reaction temperature of 300 °C, the composition of diisopropylnaphthalene isomeric mixture was quite distant from the thermodynamic equilibrium. For equilibrium composition at 250 °C 2,6DIPN and 2,7-DIPN content of 42 and 43% can be expected, respectively, and no more than 0.5% of each 1,4DIPN and 1,5-DIPN [9]. Although the 2,6-DIPN/2,7DIPN mole ratio slightly higher than 1 was observed, it resulted from the kinetics of the naphthalene alkylation. There are available literature data [14–17] which are in contradiction with our findings and a very high 2,6-DIPN selectivity and 2,6-DIPN/2,7-DIPN mole ratio were reported for alkylation of naphthalene with isopropanol over mesoporous catalysts MCM-41 and MCM-48. Some example results are compared with our results in Table 3. In the most literature cases presented in Table 3, the 2, 6-DIPN content in the DIPN product is in the range of 53–88% and is higher than that predicted thermodynamically [2,9]. Moreover, only 2,6-DIPN and 2,7-DIPN were reported among DIPN isomers [14–17]. Except for Zhao et al. [13] and Pu et al. [14], a very high 2,6-DIPN/2,7DIPN mole ratio (2.4–7.5) was also reported which is even higher than that reported for the shape selective reaction on mordenites. Such results are surprising and difficult to explain with kinetics, thermodynamics or shape selectivity. For kinetic product the 2,6-DIPN/2,7-DIPN mole ratio is slightly higher than 1 but 2,6-DIPN and 2,7-IPN content is low. Thermodynamic mixture contain mainly 2,6- and 2,7-DIPN but their ratio is close or even slightly lower than 1. For the shape selectivity both high 2,6-DIPN and 2,7DIPN content as well as high 2,6-DIPN/2,7-DIPN ratio can be expected, however, correspondingly also 2-IPN should be the only product of monoalkylation. Otherwise 1-IPN can be alkylated to a,a- or a,b-DIPN which isomers were not detected in [14–17]. Moreover, when compared with critical sizes of DIPN molecules, the pore aperture of mesoporous catalysts seems too large (>2 nm) to force shape selectivity. Nevertheless, in experiments discussed above isopropanol was used as an alkylating agent and reagents were dis-
R. Brzozowski et al. / Catalysis Communications 8 (2007) 1681–1683
1683
Table 2 Isomeric composition of DIPN obtained on Al-MCM-48 catalysts Temperature (°C)
DIPN isomeric composition (%)
2,6-/2,7-ratio
2,6-
2,7-
1,6-
1,7-
1,3-
1,4-
1,5-
Al-MCM-48(50) 250 300
7.5 9.9
6.3 6.9
13.6 14.9
15.6 17.1
18.3 22.6
25.9 18.9
12.1 9.7
1.2 1.4
Al-MCM-48(25) 150 200 250 300
0.0 6.6 16.5 31.4
0.0 5.2 13.7 28.3
14.6 14.0 15.1 10.7
21.7 15.8 13.8 8.6
14.9 22.4 26.8 17.1
30.9 23.9 7.9 1.6
17.9 11.0 5.1 1.2
– 1.3 1.2 1.1
Table 3 A comparison of isomeric composition of DIPN obtained on mesoporous catalysts Catalyst/temperature/alkylating agent
Al-MCM-41 (17)/200 °C/isopropanol Al-MCM-41/250 °C/isopropanol Al-MCM-41 (25)/200 °C/isopropanol Al-MCM-41 (25)/250 °C/isopropanol Al-MCM-41 (28)/200 °C/isopropanol Al-MCM-48 (31)/200 °C/isopropanol Al-MCM-48 (25)/250 °C/isopropanol Al-MCM-48 (25)/350 °C/isopropanol Al-MCM-48 (25)/200 °C/propylene Al-MCM-48 (25)/250 °C/propylene Al-MCM-48 (25)/250 °C/isopropanol Al-MCM-48 (25)/350 °C/isopropanol a b
2-IPN in IPN (%)
– 100 72.5 73.6 75b 85b 74.1 72.4 33.4 44.5 38.9 70.3
DIPN isomeric composition (%) 2,6-
2,7-
1,6-
1,7-
1,3-
1,4-
1,5-
38.6 83 72 71 56.1 52.9 87.5 88.2 6.6 16.5 15.9 27.8
23.5 17 28 29 43.9 47.1 12.5 11.8 5.2 13.7 12.6 24.1
4.6 n.d.a n.d. n.d. n.d. n.d. n.d. n.d. 14.0 15.1 13.3 11.1
8.6 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 15.8 13.8 14.7 9.3
18.0 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 22.4 26.8 30.6 15.7
0.0 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 23.9 7.9 7.1 1.8
6.8 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 11.0 5.1 4.4 0.9
2,6-/2,7-ratio
Ref.
1.6 4.9 2.6 2.4 1.3 1.1 7.0 7.5 1.3 1.2 1.2 1.1
[13] [15] [16] [16] [14] [14] [17] [17] This This This This
work work work work
n.d. – not detected. Extrapolated from the figure.
solved in cyclohexane, n-hexane or benzene, whereas our experiments were carried out without solvent and with propylene as an alkylating agent. In order to check the influence of solvent and different alkylating agent on the DIPN isomeric composition, the additional experiments were performed, where the alkylation feed containing naphthalene, isopropanol and cyclohexane with molar ratio 1:2:10 was used. Results of alkylation at the reaction temperature 250 and 350 °C are shown in Table 3. As is evident neither a high 2,6-DIPN selectivity nor a high 2,6-DIPN/2,7-DIPN ratio was obtained. The DIPN product composition was similar to that obtained with propylene and derived evidently from kinetics of alkylation, isomerization and other reactions occurring in the reactor. Therefore, when comparing our results with the unusual results described in the literature for mesoporous catalysts [14–17] and considering analysis methods applied there, erroneous GC analysis and DIPN identification can be concluded, similarly as discussed in [20]. References [1] J.W. Stadelhofer, R.B. Zellerhoff, Chem. Ind. (London) 1989 (1989) 208. [2] G. Tasi, F. Mizukami, I. Palinko, M. Toba, A. Kukovecz, J. Phys. Chem. A 105 (2001) 6513.
[3] A. Katayama, M. Toba, G. Takeuchi, F. Mizukami, S. Niwa, S. Mitamura, J. Chem. Soc. Chem. Commun. 1991 (1991) 39. [4] Y. Sugi, M. Toba, Catal. Today 19 (1994) 187. [5] J.A. Horsley, J.D. Fellmann, E.G. Derouane, C.M. Freeman, J. Catal. 147 (1994) 231. [6] Ch. Song, C.R. Acad. Sci. Paris, Serie IIc, Chimie/Chem. 3 (2000) 477. [7] E. Kikuchi, K. Sawada, M. Maeda, T. Matsuda, Stud. Surf. Sci. Catal. 90 (1994) 391. [8] R. Brzozowski, W. Skupin´ski, J. Catal. 220 (2003) 13. [9] R. Brzozowski, J.C. Dobrowolski, M.H. Jamro´z, W. Skupin´ski, J. Mol. Catal. A 170 (2001) 95. [10] J.-H. Kim, Y. Sugi, T. Matsuzaki, T. Hanaoka, Y. Kubota, X. Tu, M. Matsumoto, Micropor. Mater. 5 (1995) 113. [11] J.-H. Kim, Y. Sugi, T. Matsuzaki, T. Hanaoka, Y. Kubota, X. Tu, M. Matsumoto, S. Nakata, A. Kato, G. Seo, C. Pak, Appl. Catal. A 131 (1995) 15. [12] J.-H. Kim, M. Tanabe, M. Niwa, Micropor. Mater. 10 (1997) 85. [13] X.S. Zhao, M.G.Q. Lu, C. Song, J. Mol. Catal. A 191 (2003) 67. [14] S.B. Pu, J.B. Kim, M. Seno, T. Inui, Micropor. Mater. 10 (1997) 25. [15] G. Kamalakar, S.J. Kulkarni, K.V. Raghavan, S. Unnikrishnan, A.B. Halgeri, J. Mol. Catal. A 149 (1999) 283. [16] R. Maheswari, K. Shanthi, T. Sivakumar, S. Narayanan, Appl. Catal. A 245 (2003) 221. [17] T. Krithiga, A. Vinu, K. Ariga, B. Arabindoo, M. Palanichamy, V. Murugesan, J. Mol. Catal. A 237 (2005) 238. [18] R. Brzozowski, W. Skupin´ski, M.H. Jamro´z, M. Skar_zyn´ski, H. Otwinowska, J. Chromatogr. A 946 (2002) 221. [19] R. Brzozowski, W. Skupin´ski, J. Catal. 210 (2002) 313. [20] R. Brzozowski, Appl. Catal. A 272 (1–2) (2004) 215.
Alkylation of naphthalene using propylene over mesoporous Al-MCM-48 catalysts Robert Brzozowski b
a,*
, Ajayan Vinu b, Toshiyuki Mori
b
a Industrial Chemistry Research Institute, Rydygiera 8, 01-793 Warsaw, Poland Nano-ionics Materials Group, Fuel Cell Materials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
Received 16 October 2006; received in revised form 30 January 2007; accepted 30 January 2007 Available online 4 February 2007
Abstract Alkylation of naphthalene with propylene over mesoporous Al-MCM-48 catalysts with different silicon to aluminium ratios (nSi/nAl) was tested. The activity of the catalysts increased with decreasing the nSi/nAl ratio. In our experiments alkylation product composition was determined by kinetic and thermodynamic factors. Nevertheless, unfortunately, a high 2,6-diisopropylnaphthalene selectivity was not observed in our catalyst system, that was repetitively described in the literature. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Alkylation; Naphthalene; Diisopropylnaphthalene; Mesoporous material; MCM-48
1. Introduction Diisopropylnaphthalene (DIPN) isomeric mixture is used as a high quality solvent for copying materials [1]. The 2,6-DIPN, isolated from the isomeric mixture, can be used as a raw material for the production of advanced polymers. Therefore, active and stable catalysts for naphthalene alkylation are still searched for, especially those selective towards 2,6-DIPN. Wide pore zeolites are among the best candidates for selective synthesis of 2,6-DIPN. Their pore sizes (0.6– 0.75 nm) are in the range of critical sizes of DIPN isomer molecules (0.66–1 nm [2]), consequently shape selectivity effect can be expected. Wide pore zeolites can distinguish between the slim b,b-DIPN isomers and the bulky a,band a,a-isomers. Among them mordenites revealed to be very selective catalysts. DIPN products obtained over mordenites contained 40–60% of 2,6-DIPN and the 2,6DIPN to 2,7-DIPN mole ratio was much higher than 1 [3–8], i.e. the thermodynamic ratio [2,9]. Dealumination *
Corresponding author. Tel.: +48 22 568 20 20; fax: +48 22 568 21 74. E-mail address: [email protected] (R. Brzozowski).
1566-7367/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.catcom.2007.01.039
of mordenites developed both their stability and 2,6-DIPN selectivity [7,10]. Further increase of 2,6-DIPN selectivity was achieved by deactivation of the external surface of mordenite with e.g. ceria [11]. A DIPN isomeric mixture contained then even more than 70% of 2,6-DIPN and the 2,6-DIPN/2,7-DIPN ratio was in the range 2–3. Lately, catalytic applications for mesoporous materials such as MCM-41 and MCM-48 in reactions such as alkylation of naphthalene arouse interest. Generally, mesoporous silica materials are inactive in alkylation reactions due to the lack of acid sites owing to their neutral framework and ion-exchange properties. However, e.g. isomorphous substitution of metals such as Al, Ga or Fe into the mesoporous silica walls is critical for the formation of acid sites in the mesoporous channels. Owing to their ordered structure and wide pores (>2 nm), they are promising as active and stable catalysts for naphthalene alkylation to DIPN. There are available literature reports on alkylation of naphthalene with isopropanol over acidic mesoporous catalysts such as Al-MCM-41 and Al-MCM-48 [12–17]. Moreover, an unusually high 2,6-DIPN selectivity and 2,6-DIPN/2,7-DIPN mole ratio in alkylation product
1682
R. Brzozowski et al. / Catalysis Communications 8 (2007) 1681–1683
obtained over mesoporous catalysts are related [14–17]. However, alkylation of naphthalene with propylene as an alkylating agent over mesoporous catalysts has not been reported in the open literature so far. Therefore we carried out preliminary experiments on the above reaction using propylene as an alkylating agent over Al-MCM-48 catalysts with various aluminium contents. 2. Experimental Three Al-MCM-48 samples with various aluminium contents (the numbers in parentheses denote nSi/nAl ratios of the catalysts) were tested in alkylation of naphthalene with propylene. They were prepared according to the methods described elsewhere [17], where the details on their properties can also be found. Alkylation experiments were carried out in a fixed-bed reactor under pressure of 3 MPa, the naphthalene/propylene mole ratio of 1.5 and a feed flow 20 g/gh. Inlet temperature was changed in the range of 150–300 °C, starting from the lowest set point and stabilising reaction conditions for at least 1 h at each temperature. Product samples were collected and analysed by the GC method described elsewhere [18]. 3. Results and discussion Results of naphthalene alkylation with propylene on AlMCM-48 (25) and Al-MCM-48 (50) mesoporous catalysts are presented in Tables 1 and 2. The catalyst sample AlMCM-48 (100) i.e. with the lowest Al loading was almost inactive and lost its trace activity very quickly. Propylene conversion on Al-MCM-48(50) was low and the activity of the catalyst was almost lost very quickly. The highest conversion of only 44% was observed for 250 °C, in spite of shorter time on stream than that usually applied, because 200 °C temperature set point was omitted. The Al-MCM-48 (25) was the most active catalyst and a practically total conversion of propylene was achieved at the reaction temperature of 200 °C. Table 1 Results of alkylation of naphthalene with propylene on Al-MCM-48 catalysts Temperature (°C)
Propylene conversion (%)
Selectivity to (mole%)
2-IPN in IPN (%)
IPN
DIPN
Al-MCM-48(50) 150 3.0 250 44.4 300 14.4
47.4 56.6 52.8
tr.a 16.5 10.2
26.5 33.4 37.9
Al-MCM-48(25) 150 15.3 200 97.9 250 99.2 300 98.6
75.8 52.1 51.4 57.2
4.7 22.0 24.1 28.9
25.8 33.4 44.5 70.0
a
tr. – traces of DIPN were detected.
Isopropylnaphthalene (IPN) and DIPN were the main products of the alkylation of naphthalene with propylene. Other products such as tri- and tetra-isopropylnaphthalenes, alkylnaphthalenes with at least one substituent other than the isopropyl group, propylene oligomers, etc. were also observed. Al-MCM-48 catalysts revealed rather a weak isomerization activity when compared with amorphous aluminosilicate or zeolite catalysts. In the monoalkylated product no more than 70% of 2-IPN was detected (Table 1), whereas under similar alkylation conditions but at lower temperature 85–90% of 2-IPN was formed over amorphous aluminosilicate or zeolites H-beta or HY [19]. Similarly, low isomerization activity was observed in the case of diisopropylnaphthalenes (Table 2). With temperature elevation the distribution of 2,6- and 2,7-isomer in DIPN product increased, whereas that of 1,4-DIPN and 1,5-DIPN decreased. Even at such a high reaction temperature of 300 °C, the composition of diisopropylnaphthalene isomeric mixture was quite distant from the thermodynamic equilibrium. For equilibrium composition at 250 °C 2,6DIPN and 2,7-DIPN content of 42 and 43% can be expected, respectively, and no more than 0.5% of each 1,4DIPN and 1,5-DIPN [9]. Although the 2,6-DIPN/2,7DIPN mole ratio slightly higher than 1 was observed, it resulted from the kinetics of the naphthalene alkylation. There are available literature data [14–17] which are in contradiction with our findings and a very high 2,6-DIPN selectivity and 2,6-DIPN/2,7-DIPN mole ratio were reported for alkylation of naphthalene with isopropanol over mesoporous catalysts MCM-41 and MCM-48. Some example results are compared with our results in Table 3. In the most literature cases presented in Table 3, the 2, 6-DIPN content in the DIPN product is in the range of 53–88% and is higher than that predicted thermodynamically [2,9]. Moreover, only 2,6-DIPN and 2,7-DIPN were reported among DIPN isomers [14–17]. Except for Zhao et al. [13] and Pu et al. [14], a very high 2,6-DIPN/2,7DIPN mole ratio (2.4–7.5) was also reported which is even higher than that reported for the shape selective reaction on mordenites. Such results are surprising and difficult to explain with kinetics, thermodynamics or shape selectivity. For kinetic product the 2,6-DIPN/2,7-DIPN mole ratio is slightly higher than 1 but 2,6-DIPN and 2,7-IPN content is low. Thermodynamic mixture contain mainly 2,6- and 2,7-DIPN but their ratio is close or even slightly lower than 1. For the shape selectivity both high 2,6-DIPN and 2,7DIPN content as well as high 2,6-DIPN/2,7-DIPN ratio can be expected, however, correspondingly also 2-IPN should be the only product of monoalkylation. Otherwise 1-IPN can be alkylated to a,a- or a,b-DIPN which isomers were not detected in [14–17]. Moreover, when compared with critical sizes of DIPN molecules, the pore aperture of mesoporous catalysts seems too large (>2 nm) to force shape selectivity. Nevertheless, in experiments discussed above isopropanol was used as an alkylating agent and reagents were dis-
R. Brzozowski et al. / Catalysis Communications 8 (2007) 1681–1683
1683
Table 2 Isomeric composition of DIPN obtained on Al-MCM-48 catalysts Temperature (°C)
DIPN isomeric composition (%)
2,6-/2,7-ratio
2,6-
2,7-
1,6-
1,7-
1,3-
1,4-
1,5-
Al-MCM-48(50) 250 300
7.5 9.9
6.3 6.9
13.6 14.9
15.6 17.1
18.3 22.6
25.9 18.9
12.1 9.7
1.2 1.4
Al-MCM-48(25) 150 200 250 300
0.0 6.6 16.5 31.4
0.0 5.2 13.7 28.3
14.6 14.0 15.1 10.7
21.7 15.8 13.8 8.6
14.9 22.4 26.8 17.1
30.9 23.9 7.9 1.6
17.9 11.0 5.1 1.2
– 1.3 1.2 1.1
Table 3 A comparison of isomeric composition of DIPN obtained on mesoporous catalysts Catalyst/temperature/alkylating agent
Al-MCM-41 (17)/200 °C/isopropanol Al-MCM-41/250 °C/isopropanol Al-MCM-41 (25)/200 °C/isopropanol Al-MCM-41 (25)/250 °C/isopropanol Al-MCM-41 (28)/200 °C/isopropanol Al-MCM-48 (31)/200 °C/isopropanol Al-MCM-48 (25)/250 °C/isopropanol Al-MCM-48 (25)/350 °C/isopropanol Al-MCM-48 (25)/200 °C/propylene Al-MCM-48 (25)/250 °C/propylene Al-MCM-48 (25)/250 °C/isopropanol Al-MCM-48 (25)/350 °C/isopropanol a b
2-IPN in IPN (%)
– 100 72.5 73.6 75b 85b 74.1 72.4 33.4 44.5 38.9 70.3
DIPN isomeric composition (%) 2,6-
2,7-
1,6-
1,7-
1,3-
1,4-
1,5-
38.6 83 72 71 56.1 52.9 87.5 88.2 6.6 16.5 15.9 27.8
23.5 17 28 29 43.9 47.1 12.5 11.8 5.2 13.7 12.6 24.1
4.6 n.d.a n.d. n.d. n.d. n.d. n.d. n.d. 14.0 15.1 13.3 11.1
8.6 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 15.8 13.8 14.7 9.3
18.0 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 22.4 26.8 30.6 15.7
0.0 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 23.9 7.9 7.1 1.8
6.8 n.d. n.d. n.d. n.d. n.d. n.d. n.d. 11.0 5.1 4.4 0.9
2,6-/2,7-ratio
Ref.
1.6 4.9 2.6 2.4 1.3 1.1 7.0 7.5 1.3 1.2 1.2 1.1
[13] [15] [16] [16] [14] [14] [17] [17] This This This This
work work work work
n.d. – not detected. Extrapolated from the figure.
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