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Control of micropore size in supermicroporous titania–chromia system TiO2–Cr2O3
Inorganic Chemistry Communications 9 (2006) 1136–1140 www.elsevier.com/locate/inoche
Control of micropore size in supermicroporous titania–chromia system TiO2–Cr2O3 Windlyne Delouis a, Marcos Sanchez a, Boris Shpeizer b, Abraham Clearfield b, Aderemi Oki a,* a
Department of Chemistry, Prairie View A&M University, Prairie View, TX 77446, USA b Department of Chemistry, Texas A&M University, College Station, TX 77842, USA Received 17 February 2006; accepted 14 July 2006 Available online 2 August 2006
Abstract Sol–gel hydrolysis reactions of titanium(IV) isopropoxide and chromium (III) acetate hydroxide in the presence or absence of propanol, using the following amines as structure directing agents; N-hexylamine, N-methylhexylamine, and N-propylbutylamine, yielded micropo˚ region, and surface areas that vary from 564 m2/g when N-hexrous mixed metal oxides with the presence of pores largely in the 10–20 A 2 ylamine is employed as pore directing template to 494 m /g when N-propylbutyl amine is employed as template. The maxima in pore size distribution increases with increase in steric crowding around the nitrogen in the alkyl amine. In addition, the nitrogen adsorption–desorption isotherm shifted from Type 1 isotherm when N-hexylamine is used as templating agent to Type 4 isotherm in N-propylbutylamine. Ó 2006 Elsevier B.V. All rights reserved. Keywords: Hexylamine; Pore; Titania; Chromia; Sol–gel hydrolysis
The well known zeolites, microporous crystalline aluminosilicates exhibit uniform pore size distribution, high thermal and hydrothermal stability, and a wide spectrum of acidities and shape selectivity [1–3]. These properties permit a broad range of applications for zeolites, that include ion exchangers, sorbent materials and selective catalytic applications. However, the limitation in the pore size and chan˚ ), has restricted their nel dimension (generally less than 9 A applications in wider areas of catalysis, especially involving bulky organic molecules. In addition, the reactivity of the elements that make up the zeolites, particularly of the Al– O and Si–O bonds, limits their operating pH range between 2 and 12. The use of surfactants with moderately long alkyl chain lengths are known to yield mesoporous materials with ˚ range [2–13]. There is therefore pore sizes in the 20–200 A the need to develop a simple method for the synthesis of ˚. porous mixed metal oxides with pore sizes in the 10–20 A
*
Corresponding author. Tel.: +1 936 261 3105; fax: +1 936 857 2950. E-mail address: [email protected] (A. Oki).
1387-7003/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2006.07.031
Such material should bridge the pore size gap between the ˚ ) and the mesoporous oxides (>20 A ˚ ). Clearzeolites (<10 A field et al. recently reported a general procedure for making such super-microporous mixed metal oxides starting from metal alkoxides or acetates and n-alkylamine as templates using propanol/water mixture as solvent (14). In this report, a direct relationship between the maxima in pore size distribution and the hydrocarbon chain length in the n-alkylamine was reported. Using six, seven, eight, nine and ten carbon chain primary alkyl amine, they were able to progressively increase the maxima in pore size distribution in ˚ [14]. Following a slight modification of the prothe 10–20 A cedure reported by Clearfield et al. [14] for the synthesis of microporous mixed chromia–zirconia system, the current investigation shows that such relationship can also be established by varying the steric crowding around the alkylamine. In the present study, the relationship between the following amines: N-hexylamine, N-methylhexylamine and N-propylbutylamine and the maxima in pore size distribution and surface areas in the titania–chromia system is established. In addition, the role of solvent is also investigated
W. Delouis et al. / Inorganic Chemistry Communications 9 (2006) 1136–1140
in this systems. The syntheses of the Cr2O3–TiO2 system was accomplished by reacting a pre-hydrolyzed chromium acetate hydroxide with titanium (IV) isopropoxide in propanol, followed by addition of respective alkylamine, and sequential addition of water–propanol mixture drop-wise over a period of one hour. The solution was left stirring for 24 h, forming a gel, to which additional water was added and refluxed for 24 h. The solid was separated by centrifuge,
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and dried in an oven at 65 °C. The products obtained using N-hexylamine, N-methylhexyl amine and N-propylbutylamine are labeled 1, 2 and 3, respectively [15]. The dried materials were characterized by TGA, FTIR and elemental analysis using an energy dispersive standardless elemental analyzer [15]. The sorption–desorption isotherms for the mixed chromia–titania oxides were obtained using the nitrogen sorption
Fig. 1. Pore size distribution curve for isotherm for 1, as determined by the MP method.
Fig. 2. The N2 sorption–desorption isotherm for Cr2O3–TiO2 compounds 1, 2 and 3.
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W. Delouis et al. / Inorganic Chemistry Communications 9 (2006) 1136–1140
Fig. 3. Shows the pore size distribution curve for 2, as determined by the MP method. Table 1 BET and micropore surface areas for chromia–titania compounds 1, 2 and 3 Sample ID
Total pore volume cc/g
˚ Maximum in pore size distribution curve/A
BET surface area/m2 g
1 2 3
0.253 0.32 0.33
9.0 12–14 13–15
564 523 494
method after outgassing and heating the samples for 24 h at 260 °C before the collection of isotherm data. The isotherm of 1 is indicative of type 1 materials, while the isotherms of compounds 2 and 3, indicate a type IV, signifying the presence of mesopores. The maxima in pore size distribution for compounds 1, (Fig. 1) 2 and 3 are 9, 13 ˚ , respectively. The isotherms are displayed in and 14 A Fig. 2, while Fig. 3 is the pore size distribution for 2. The FTIR of all of these compounds combined with TGA confirmed the loss of the alkylamine after heating at 260 °C. The surface areas decrease as the size of the group around the nitrogen Table 1 in the alkylamine gets bigger. ˚ shows a progressive The pore size distribution of 10–20 A increase from N-hexylamine to N-methylhexylamine to N-propylbutylamine. A small portion of the pores were ˚ range, with the highest amount observed in the 20–30 A in compound 3. The synthesis of microporous mixed chromia–titania oxides can also be accomplished in the absence of solvent. In a typical procedure, the basic chromium acetate is added to the titanium(IV) isopropoxide, followed by addition of N-hexylamine as template and stirred overnight. The volatiles were removed by heating at 150 °C
1
t-Method micropore surface area/m2 g 1 560 506 478
overnight to yield compound 4. The FTIR of samples heated at 150°C, 260°C and 450 °C are presented in Figs. 4a, 4b and 4c respectively. After calcination at 260 °C for 24 h, the FTIR showed the presence of acetate peaks, around 1561(s) and 1451(s) cm 1, which disappeared after heating the sample to 450 °C (see Fig. 4c). The nitrogen adsorption isotherm obtained for materials prepared in the absence of any solvent, after calcination at 260 °C showed microporous solid with maximum in pore ˚ , and a type 1 isotherm (Fig. 4d). size distribution at 10 A The isotherm also showed increase of pores in the 20– ˚ region when compared to compound 1. The BET sur30 A face area and the t-Method micropore surface area for this compound are 409 and 405 m2 g 1, respectively, and are lower than the respective values in compound 1. This is likely due to the entrapment of the acetate ions in the pores at 260 °C. Heating this sample to 450 °C changed the nature of the isotherm to a pseudo type IV, signifying the presence of larger pores and the maximum in ˚ . The shift pore size distribution curve increased to 13 A to larger pores and type IV isotherm could partly be due to the loss of the residual acetate trapped in the pore.
3904 3840 3805 3754
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W. Delouis et al. / Inorganic Chemistry Communications 9 (2006) 1136–1140
1030
6.0 5.5
2929
4.0
433
2860
4.5 3447
%T
5.0
674
3.5 3.0
1562
2.5 1451
2.0 3500
4000
3000
2500
2000
1500
1000
500
Wavenumbers (cm -1)
Fig. 4a. FTIR of 4 heated at 150 °C for 24 h.
10.5 10.0 9.5 9.0
8.0 7.5
3652
%T
8.5
673
7.0 2930
6.5
5.5
4000
1561
5.0 3500
3000
2500
2000
1451
3409
6.0
1500
1000
500
Wavenumbers (cm -1)
Fig. 4b. FTIR of 4 after heating the sample at 260 °C for 24 h.
16.2 16.0 15.8 15.6 15.4 15.2
14.8 14.6 14.4
13.6
625
2371
13.8
1623
14.0
1544
14.2 3399
13.4 13.2 13.0 4000
1384
%T
15.0
3500
3000
2500
2000
1500
Wavenumbers (cm -1)
Fig. 4c. FTIR of 4 after heating sample at 450 °C for 24 h.
1000
500
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Fig. 4d. N2 isotherm of compound 4. The TiO2–Cr2O3 prepared in the absence of solvent.
It thus appears that the organic amine not only directs the pore size distribution, but also plays a role in the hydrolysis reaction of the metal alkoxides and metal acetates. We have also looked at the synthesis of compound 1 using ethylene glycol as the solvents, and the result is similar to what we observed using propanol–water mixture. In summary, mixed metal oxides of controlled pore sizes ˚ range can be synthesized using alkyl amine in the 10–20 A as templating agent in the presence or absence of solvent. The maximum in pore size distribution can be controlled by temperature and the choice of the alkylamine. In general, increasing the size of group around amine nitrogen increases pore size maxima and pore size distribution moves to increasingly larger pores. This can also be accomplished by temperature treatment, and variation in hydrocarbon chain length. Future work will investigate the use of isomeric 1°, 2° and 3° amines and their respective ammonium salts as pore directing agent and establish the trend in pore size distribution, surface areas and the nature of the isotherms. This and other studies are currently being investigated in our laboratory. Acknowledgements The PIs acknowledge the support from NIH-NIAMSD Grant # ARO149172, the Welch Foundation grant to PVAMU Chemistry Department (L0002), Center for Environmental Beneficial Catalysis, CEBC (EEC-0310689) the National Science Foundation Summer Fellowship in Solid State Chemistry under Award No. DMR 0303450. References [1] J.S. Beck, J.C. Vartuli, W.J. Roth, M.E. Leonowicz, C.T. Kresge, K.D. Schmitt, C.W. Chu, D.H. Olsen, W.W. Sheppard, S.B. McCullen, J.B. Higgins, J.L. Schlenker, J. Am. Chem. Soc. 114 (1992) 10834.
[2] C.T. Kresge, M.E. Leonowicz, M.E. Roth, W.J. Vartuli, J.S. Beck, Nature 359 (1992) 710. [3] F. Schut, Chem. Mater. 13 (2001) 3184, and ref. therein. [4] M.E. Davis, Nature 417 (2002) 813. [5] M.E. Davis, Acct. Chem. Res. 26 (1993) 111. [6] P. Taner, T.J. Pinnavair, Science 267 (1995) 865. [7] S. Polarz, M. Antoinette, Chem. Commun. (2002) 2593. [8] M. Yada, M. Machida, T. Kijima, Chem. Commun. (1996) 769. [9] S. Cabrera, J. El Haskouri, C. Guillen, J. Latore, A. Beltrain-Porter, D. Beltrain Porter, M.D. Marcos, P. Amorios, Sol. State Sci. 2 (2000) 405. [10] A. Corma, M.E. Davies, Chem. Phys. Chem. (2004) 304, and ref. therein. [11] T. Sun, M.S. Wong, J.Y. Ying, Chem. Commun. (2000) 2057. [12] T. Sun, J.Y. Ying, Angew. Chem., Int. Ed. 37 (1998) 664. [13] M.S. Wong, H.C. Huang, J.Y. Ying, Chem. Mater. 9 (1997) 2491. [14] B. Shpeizer, A. Clearfield, J.M. Heising, Chem. Commun. 18 (2005) 2396–2398. [15] In a 250 ml round bottom flask was added 1.354 g (0.0022 mol) chromium acetate hydroxide (Aldrich) and 8.26 g of propanol (Aldrich) and the mixture was stirred for 15 min, this was followed by addition of 2.410 g (0.0085 mol) of titanium (IV) isopropoxide (Aldrich) and stirring continued for 15 min, followed by addition of 2.63 g (0.026 mol) of N-hexylamine. After 20 min, a series of water– propanol mixtures of varying compositions were added sequentially (1.85 g water/9.22 g propanol; 3.65 g water/7.60 g propanol; and finally 9.01 g water/5.29 g propanol), dropwise over a period of one hour. The solution was left stirring for 24 h, forming a gel. To the gel was added 12.60 g water and refluxed overnight, cooled to room temperature and centrifuged. The isolated solid was washed with ethanol, filtered and dried at 60 °C for 24 h to give 2.63 gm dark green solid 1. Compounds 2 and 3 were prepared by following the same procedure but using N-methyhexlamine and N-propylbutylamine instead of N-hexylamine. The yields are 2.58 and 2.45 gm, respectively. FT-IR data KBr (cm 1): 2850–2962(s) C–H, 1385(s), 1365(s), C–H, isopropyl. All of these peaks disappeared after calcination at 260 °C. The elemental analysis of samples were carried out at Cornell Center for materials Research (CCMR), at the Optical and Microscope Facility. The EDS detector was made by Thermo-Noran using Vantage system that includes standardless EDS software for processing the spectra to obtain the quantitative elemental analysis. The energy dispersive standardless elemental analysis showed the atoms ratio of Ti:Cr in the compounds calcined at 260 °C to be approximately 3:2.
Control of micropore size in supermicroporous titania–chromia system TiO2–Cr2O3 Windlyne Delouis a, Marcos Sanchez a, Boris Shpeizer b, Abraham Clearfield b, Aderemi Oki a,* a
Department of Chemistry, Prairie View A&M University, Prairie View, TX 77446, USA b Department of Chemistry, Texas A&M University, College Station, TX 77842, USA Received 17 February 2006; accepted 14 July 2006 Available online 2 August 2006
Abstract Sol–gel hydrolysis reactions of titanium(IV) isopropoxide and chromium (III) acetate hydroxide in the presence or absence of propanol, using the following amines as structure directing agents; N-hexylamine, N-methylhexylamine, and N-propylbutylamine, yielded micropo˚ region, and surface areas that vary from 564 m2/g when N-hexrous mixed metal oxides with the presence of pores largely in the 10–20 A 2 ylamine is employed as pore directing template to 494 m /g when N-propylbutyl amine is employed as template. The maxima in pore size distribution increases with increase in steric crowding around the nitrogen in the alkyl amine. In addition, the nitrogen adsorption–desorption isotherm shifted from Type 1 isotherm when N-hexylamine is used as templating agent to Type 4 isotherm in N-propylbutylamine. Ó 2006 Elsevier B.V. All rights reserved. Keywords: Hexylamine; Pore; Titania; Chromia; Sol–gel hydrolysis
The well known zeolites, microporous crystalline aluminosilicates exhibit uniform pore size distribution, high thermal and hydrothermal stability, and a wide spectrum of acidities and shape selectivity [1–3]. These properties permit a broad range of applications for zeolites, that include ion exchangers, sorbent materials and selective catalytic applications. However, the limitation in the pore size and chan˚ ), has restricted their nel dimension (generally less than 9 A applications in wider areas of catalysis, especially involving bulky organic molecules. In addition, the reactivity of the elements that make up the zeolites, particularly of the Al– O and Si–O bonds, limits their operating pH range between 2 and 12. The use of surfactants with moderately long alkyl chain lengths are known to yield mesoporous materials with ˚ range [2–13]. There is therefore pore sizes in the 20–200 A the need to develop a simple method for the synthesis of ˚. porous mixed metal oxides with pore sizes in the 10–20 A
*
Corresponding author. Tel.: +1 936 261 3105; fax: +1 936 857 2950. E-mail address: [email protected] (A. Oki).
1387-7003/$ - see front matter Ó 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.inoche.2006.07.031
Such material should bridge the pore size gap between the ˚ ) and the mesoporous oxides (>20 A ˚ ). Clearzeolites (<10 A field et al. recently reported a general procedure for making such super-microporous mixed metal oxides starting from metal alkoxides or acetates and n-alkylamine as templates using propanol/water mixture as solvent (14). In this report, a direct relationship between the maxima in pore size distribution and the hydrocarbon chain length in the n-alkylamine was reported. Using six, seven, eight, nine and ten carbon chain primary alkyl amine, they were able to progressively increase the maxima in pore size distribution in ˚ [14]. Following a slight modification of the prothe 10–20 A cedure reported by Clearfield et al. [14] for the synthesis of microporous mixed chromia–zirconia system, the current investigation shows that such relationship can also be established by varying the steric crowding around the alkylamine. In the present study, the relationship between the following amines: N-hexylamine, N-methylhexylamine and N-propylbutylamine and the maxima in pore size distribution and surface areas in the titania–chromia system is established. In addition, the role of solvent is also investigated
W. Delouis et al. / Inorganic Chemistry Communications 9 (2006) 1136–1140
in this systems. The syntheses of the Cr2O3–TiO2 system was accomplished by reacting a pre-hydrolyzed chromium acetate hydroxide with titanium (IV) isopropoxide in propanol, followed by addition of respective alkylamine, and sequential addition of water–propanol mixture drop-wise over a period of one hour. The solution was left stirring for 24 h, forming a gel, to which additional water was added and refluxed for 24 h. The solid was separated by centrifuge,
1137
and dried in an oven at 65 °C. The products obtained using N-hexylamine, N-methylhexyl amine and N-propylbutylamine are labeled 1, 2 and 3, respectively [15]. The dried materials were characterized by TGA, FTIR and elemental analysis using an energy dispersive standardless elemental analyzer [15]. The sorption–desorption isotherms for the mixed chromia–titania oxides were obtained using the nitrogen sorption
Fig. 1. Pore size distribution curve for isotherm for 1, as determined by the MP method.
Fig. 2. The N2 sorption–desorption isotherm for Cr2O3–TiO2 compounds 1, 2 and 3.
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W. Delouis et al. / Inorganic Chemistry Communications 9 (2006) 1136–1140
Fig. 3. Shows the pore size distribution curve for 2, as determined by the MP method. Table 1 BET and micropore surface areas for chromia–titania compounds 1, 2 and 3 Sample ID
Total pore volume cc/g
˚ Maximum in pore size distribution curve/A
BET surface area/m2 g
1 2 3
0.253 0.32 0.33
9.0 12–14 13–15
564 523 494
method after outgassing and heating the samples for 24 h at 260 °C before the collection of isotherm data. The isotherm of 1 is indicative of type 1 materials, while the isotherms of compounds 2 and 3, indicate a type IV, signifying the presence of mesopores. The maxima in pore size distribution for compounds 1, (Fig. 1) 2 and 3 are 9, 13 ˚ , respectively. The isotherms are displayed in and 14 A Fig. 2, while Fig. 3 is the pore size distribution for 2. The FTIR of all of these compounds combined with TGA confirmed the loss of the alkylamine after heating at 260 °C. The surface areas decrease as the size of the group around the nitrogen Table 1 in the alkylamine gets bigger. ˚ shows a progressive The pore size distribution of 10–20 A increase from N-hexylamine to N-methylhexylamine to N-propylbutylamine. A small portion of the pores were ˚ range, with the highest amount observed in the 20–30 A in compound 3. The synthesis of microporous mixed chromia–titania oxides can also be accomplished in the absence of solvent. In a typical procedure, the basic chromium acetate is added to the titanium(IV) isopropoxide, followed by addition of N-hexylamine as template and stirred overnight. The volatiles were removed by heating at 150 °C
1
t-Method micropore surface area/m2 g 1 560 506 478
overnight to yield compound 4. The FTIR of samples heated at 150°C, 260°C and 450 °C are presented in Figs. 4a, 4b and 4c respectively. After calcination at 260 °C for 24 h, the FTIR showed the presence of acetate peaks, around 1561(s) and 1451(s) cm 1, which disappeared after heating the sample to 450 °C (see Fig. 4c). The nitrogen adsorption isotherm obtained for materials prepared in the absence of any solvent, after calcination at 260 °C showed microporous solid with maximum in pore ˚ , and a type 1 isotherm (Fig. 4d). size distribution at 10 A The isotherm also showed increase of pores in the 20– ˚ region when compared to compound 1. The BET sur30 A face area and the t-Method micropore surface area for this compound are 409 and 405 m2 g 1, respectively, and are lower than the respective values in compound 1. This is likely due to the entrapment of the acetate ions in the pores at 260 °C. Heating this sample to 450 °C changed the nature of the isotherm to a pseudo type IV, signifying the presence of larger pores and the maximum in ˚ . The shift pore size distribution curve increased to 13 A to larger pores and type IV isotherm could partly be due to the loss of the residual acetate trapped in the pore.
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1030
6.0 5.5
2929
4.0
433
2860
4.5 3447
%T
5.0
674
3.5 3.0
1562
2.5 1451
2.0 3500
4000
3000
2500
2000
1500
1000
500
Wavenumbers (cm -1)
Fig. 4a. FTIR of 4 heated at 150 °C for 24 h.
10.5 10.0 9.5 9.0
8.0 7.5
3652
%T
8.5
673
7.0 2930
6.5
5.5
4000
1561
5.0 3500
3000
2500
2000
1451
3409
6.0
1500
1000
500
Wavenumbers (cm -1)
Fig. 4b. FTIR of 4 after heating the sample at 260 °C for 24 h.
16.2 16.0 15.8 15.6 15.4 15.2
14.8 14.6 14.4
13.6
625
2371
13.8
1623
14.0
1544
14.2 3399
13.4 13.2 13.0 4000
1384
%T
15.0
3500
3000
2500
2000
1500
Wavenumbers (cm -1)
Fig. 4c. FTIR of 4 after heating sample at 450 °C for 24 h.
1000
500
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Fig. 4d. N2 isotherm of compound 4. The TiO2–Cr2O3 prepared in the absence of solvent.
It thus appears that the organic amine not only directs the pore size distribution, but also plays a role in the hydrolysis reaction of the metal alkoxides and metal acetates. We have also looked at the synthesis of compound 1 using ethylene glycol as the solvents, and the result is similar to what we observed using propanol–water mixture. In summary, mixed metal oxides of controlled pore sizes ˚ range can be synthesized using alkyl amine in the 10–20 A as templating agent in the presence or absence of solvent. The maximum in pore size distribution can be controlled by temperature and the choice of the alkylamine. In general, increasing the size of group around amine nitrogen increases pore size maxima and pore size distribution moves to increasingly larger pores. This can also be accomplished by temperature treatment, and variation in hydrocarbon chain length. Future work will investigate the use of isomeric 1°, 2° and 3° amines and their respective ammonium salts as pore directing agent and establish the trend in pore size distribution, surface areas and the nature of the isotherms. This and other studies are currently being investigated in our laboratory. Acknowledgements The PIs acknowledge the support from NIH-NIAMSD Grant # ARO149172, the Welch Foundation grant to PVAMU Chemistry Department (L0002), Center for Environmental Beneficial Catalysis, CEBC (EEC-0310689) the National Science Foundation Summer Fellowship in Solid State Chemistry under Award No. DMR 0303450. References [1] J.S. Beck, J.C. Vartuli, W.J. Roth, M.E. Leonowicz, C.T. Kresge, K.D. Schmitt, C.W. Chu, D.H. Olsen, W.W. Sheppard, S.B. McCullen, J.B. Higgins, J.L. Schlenker, J. Am. Chem. Soc. 114 (1992) 10834.
[2] C.T. Kresge, M.E. Leonowicz, M.E. Roth, W.J. Vartuli, J.S. Beck, Nature 359 (1992) 710. [3] F. Schut, Chem. Mater. 13 (2001) 3184, and ref. therein. [4] M.E. Davis, Nature 417 (2002) 813. [5] M.E. Davis, Acct. Chem. Res. 26 (1993) 111. [6] P. Taner, T.J. Pinnavair, Science 267 (1995) 865. [7] S. Polarz, M. Antoinette, Chem. Commun. (2002) 2593. [8] M. Yada, M. Machida, T. Kijima, Chem. Commun. (1996) 769. [9] S. Cabrera, J. El Haskouri, C. Guillen, J. Latore, A. Beltrain-Porter, D. Beltrain Porter, M.D. Marcos, P. Amorios, Sol. State Sci. 2 (2000) 405. [10] A. Corma, M.E. Davies, Chem. Phys. Chem. (2004) 304, and ref. therein. [11] T. Sun, M.S. Wong, J.Y. Ying, Chem. Commun. (2000) 2057. [12] T. Sun, J.Y. Ying, Angew. Chem., Int. Ed. 37 (1998) 664. [13] M.S. Wong, H.C. Huang, J.Y. Ying, Chem. Mater. 9 (1997) 2491. [14] B. Shpeizer, A. Clearfield, J.M. Heising, Chem. Commun. 18 (2005) 2396–2398. [15] In a 250 ml round bottom flask was added 1.354 g (0.0022 mol) chromium acetate hydroxide (Aldrich) and 8.26 g of propanol (Aldrich) and the mixture was stirred for 15 min, this was followed by addition of 2.410 g (0.0085 mol) of titanium (IV) isopropoxide (Aldrich) and stirring continued for 15 min, followed by addition of 2.63 g (0.026 mol) of N-hexylamine. After 20 min, a series of water– propanol mixtures of varying compositions were added sequentially (1.85 g water/9.22 g propanol; 3.65 g water/7.60 g propanol; and finally 9.01 g water/5.29 g propanol), dropwise over a period of one hour. The solution was left stirring for 24 h, forming a gel. To the gel was added 12.60 g water and refluxed overnight, cooled to room temperature and centrifuged. The isolated solid was washed with ethanol, filtered and dried at 60 °C for 24 h to give 2.63 gm dark green solid 1. Compounds 2 and 3 were prepared by following the same procedure but using N-methyhexlamine and N-propylbutylamine instead of N-hexylamine. The yields are 2.58 and 2.45 gm, respectively. FT-IR data KBr (cm 1): 2850–2962(s) C–H, 1385(s), 1365(s), C–H, isopropyl. All of these peaks disappeared after calcination at 260 °C. The elemental analysis of samples were carried out at Cornell Center for materials Research (CCMR), at the Optical and Microscope Facility. The EDS detector was made by Thermo-Noran using Vantage system that includes standardless EDS software for processing the spectra to obtain the quantitative elemental analysis. The energy dispersive standardless elemental analysis showed the atoms ratio of Ti:Cr in the compounds calcined at 260 °C to be approximately 3:2.