INTERNATIONAL JOURNAL OF FRONTIERS IN SCIENCE AND TECHNOLOGY www.ijfstonline.org Research Article ISSN 2321 – 0494 Indexed in CAS, OPEN J-gate and GOOGLE SCHOLAR Received on: 20.4.2014., Revised and Accepted on: 27.5.14
Catalytic Activity of Solid Base Catalyst for Benzaldehyde Condensation Reaction D. Divyaa, T. Somanathanb,*, N. Meeraa, N. Gokulakrishnanb, A. Saravananb and V. Mohanakrishnab a Department of Chemistry, School of Basic Sciences, Vels University, Chennai – 600 117, India b Department of Nanoscience, School of Basic Sciences, Vels University, Chennai – 600 117, India
Abstract A highly efficient and stable solid-base catalyst (MgO) was prepared by simple precipitation method. The synthesised material were characterised by various physicochemical techniques like x-ray diffraction (XRD), fourier transform infra red (FT-IR) Spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM). The catalytic activity of characterized solid base catalyst was tested towards the benzaldehyde condensation reaction in a simple way. It was found that MgO can effectively catalyse for the Aldol condensation of cyclohexanone and benzaldehyde to produce 2- benzylidenecyclohexanone with a good selectivity and high yield of 95.8% in a short period of time. The temperature play a vital role to increase the yield of the product and it was further characterised by gas chromatography (GC). Keywords: Aldol Condensation, Benzaldehyde, Cyclohexanone, MgO Catalyst, SEM and TEM *Corresponding Author: Dr.T.Somanathan
E-mail address:
[email protected]
1. Introduction Catalysis has become an important field of applied science interfaced with technology as almost all valuable products for human needs are obtained through catalytic reactions. Many industries, in particular, petroleum, petrochemical, fine chemical and allied industries have benefited from the technological advancements in this area of catalysis. With more and more stringent demand for clean environment, it
Apr-June 2014
Volume 2 Issue2
Page 19
T. Somanathan.et.al
www.ijfstonline.org
has become essential to devise novel catalysts and processes to reduce raw material consumption, energy and wastage. The studies on the catalysis by solid acids are abundant. Though a little attention is devoted to solid base catalysts in comparison with solid acid catalysts, high activities and selectivities are often attained only by only solid bases for many kinds of reactions such as alkylations, acylations, oxidation, additions, isomerization and condensation. A recent topic of interest in the Aldol condensation is the use of solid base catalysts. Important role of Aldol condensation in the reaction involving C–C bond formation makes it necessary for obtaining many fine chemicals of commercial interest. This kind of reaction can catalytically undergo in the presence of a strong base or acid in liquid phase [1–3]. However, high operating costs and serious environmental issues associated with product separation, purification, corrosion and waste generation attract great efforts toward the development of processes mediated by heterogeneous catalysts [4]. Here, in this study we have prepared MgO solid base catalyst and characterised by various techniques like XRD, FTIR, SEM and TEM. The catalytic activity of MgO solid base catalyst was tested for the Aldol condensation of cyclohexanone and benzaldehydes. The influence of temperature was also investigated.
2. Experimental 2.1
Synthesis of solid base MgO catalysts In this section we describe the synthesis of magnesium oxide were prepared by
precipitation method according our previous report [5]. 0.5 M solution of magnesium nitrate was prepared by using 100 mL of distilled water. Then 50 mL of a concentrated solution of sodium hydroxide (1 M) were added to the above solution Apr-June 2014
Volume 2 Issue2
Page 20
T. Somanathan.et.al
www.ijfstonline.org
under vigorous stirring (the milky suspension of the Mg(OH) 2 particles was produced. Suspension was stirred continuously for 1 hr at 50- 60 °C. Then the resultant product of Mg(OH)2 was sonicated for 10 min. The fine precipitates were filtered using Whatmann filter paper. Then the filtrate was placed into atmospheric oven at 400 °C for 3 h to produce solid base MgO nanoparticles catalyst.
2.2
Aldol condensation activity test The aldol condensation reaction was carried out using MgO as a catalytic
support by liquid phase reactor to according to the previous report [6]. Take 0.6 mmol cyclohexanone (99%) and 0.5 mmol purified benzaldehyde (99.9%) (molar ratio of benzaldehyde: cyclohexanone = 2 : 1) were added into 20 ml ethanol in a 50 ml round bottom flask equipped with magnetic stirrer and condenser, and then about 0.25 mmol catalysts was introduced in a constant temperature. The reaction mixture was heated at required reaction temperature ranging from 40 to 90 °C at atmospheric pressure. After the completion of reaction, the liquid was cooled and filtrated from the mixture and analysed by gas chromatography. The conversion and selectivity were calculated by area normalization method on a carbon basis and the carbon balances are within 100 ± 5% 2.3
Characterisation of carbon nanotubes XRD pattern of catalyst were obtained using Cu-K radiation (λ 0.1541 nm).
FT-IR spectrophotometer (Nicolet Nexus 670, USA) was used to identify the surface group over the catalyst. SEM image of the resulting product were measured by using JEOL JSM 840 A. Transmission electron microscope (TEM) was performed with a CM200 Philips microscope operating at 200 kV. The conversion of the product was analysed by gas chromatography using a flame ionization detector and HP-5 capillary
Apr-June 2014
Volume 2 Issue2
Page 21
T. Somanathan.et.al
www.ijfstonline.org
column of 30m length and 0.25mm diameter, programmed oven temperature of 50–280 °C and N2 (1.5 ml/min) as a carrier gas. 3. Result and Discussion 3.1 XRD Pattern of Mg(OH)2 and MgO Nanoparticles The XRD spectrum shown in Figure.1a and 1b for Mg(OH)2 and MgO Nanoparticles, respectively. Figure 1a depicts the XRD pattern of Mg(OH)2 precipitated at 60 °C. The multiple diffraction peaks from Mg(OH)2 at 20°, 40°, 50°, 60°, 70° and 80° arise from the 001, 100, 011, 012, 110 and 200 planes respectively according to a reported by Sundrarajan et al [7,8]. This confirmed that the formation and precipitation of pure Mg(OH)2 nanoparticles at 60 °C. Figure 1b is the XRD pattern of MgO nanoparticles obtained after calcination of Mg(OH)2 at 400 °C. The calcined sample had all the diffraction peaks at 30°, 44° and 65° are assigned to 111, 200 and 222 planes, respectively (JCPDS card 45-0946). This clearly indicated that Mg(OH)2 was completely transformed to crystalline MgO with no peaks detected for other phases. The results also show that calcining at the relatively low temperature of 400°C is adequate to obtained MgO nanoparticles by precipitation method.
Intensity (counts)
(b) MgO
(a) Mg(OH)2
10
20
30
40
50
60
70
80
90
2 (degree)
Figure.1 (a) XRD Pattern of Mg(OH)2 and (b) XRD Pattern of MgO nanoparticles
Apr-June 2014
Volume 2 Issue2
Page 22
T. Somanathan.et.al 3.2
www.ijfstonline.org
FT-IR Spectrum of MgO Nanoparticles The FT-IR spectrum of MgO solid base catalyst is shown in Figure.2 The
spectra represent the absorbance characteristic of high purity MgO nanoparticles. The –OH stretching vibration band at 3310 cm-1 and broad envelop between them is attributed to the presence of physisorbed and chemisorbed H2O [9] Peak observed at 785 cm-1 indicates the complete formation of cubic MgO [10,11], where as the band at near 1380cm-1 is assigned as Mg-O vibration [12]. Excitation peak observed broadly at 559 cm-1 which is generally regarded as a surface mode associated with lattice vibrations [13], which illustrate the fundamental lattice vibrations (phonon) of MgO nanoparticles due to creation or annihilation of lattice vibrations.
Intensity (a.u.)
559 cm-1
785 cm-1 1380 cm-1 -1
3310 cm 4000
3000
2000
1000
Wave number (cm-1)
Figure. 2 FT-IR Spectrum of MgO Nanoparticles 3.3
SEM of MgO Nanoparticles The SEM image shown in Figure 3, shows the MgO nanoparticles synthesized
were in excellent and more porous nanostructure (moss shape). Finally, it can be concluded that using precipitation method we can able to prepare well dispersed MgO nanoparticles with uniform diameter. Further the result was confirmed by TEM analysis.
Apr-June 2014
Volume 2 Issue2
Page 23
T. Somanathan.et.al
www.ijfstonline.org
100 nm
Figure.3 SEM Image of MgO nanoparticles
3.4 TEM image of MgO nanoparticles HRTEM studies show that the formation of particles which is clearly shown in Figure.4. It seems that the particles are uniform size and well dispersed. Precipitation method is a very simple and useful technique for the synthesis of MgO nanoparticles with more defined particles and uniform diameter of 35 nm [8,14].
Figure 4. TEM image of MgO Nanoparticles
3.5
Catalytic Activity of MgO Nanoparticles in Condensation Reaction
3.5.1 Effect of Temperature
Apr-June 2014
Volume 2 Issue2
Page 24
T. Somanathan.et.al
www.ijfstonline.org
The influence of the reaction temperature was investigated using a cyclohexanone / benzaldehyde molar ratio of 1:2 and 100 mg of MgO nanoparticles. The yield of 2-benzylidenecyclohexanone was increases with increase in the reaction temperatures ranging from 40 to 80°C was presented in the Figure. 5. The results show that a yield of 50.6% at 40°C was obtained after 6 h. With increase in the reaction temperature above 80°C, there is decrease in the yield, this is due to deactivation of the catalyst [15]. Further we conferred the optimum reaction temperature is 80 °C to achieve high yield and the obtained sample was analysed with GC. The percentage yield of the product was calculated using area normalization method [16].
Yield (%)
120 100 80 60 40 20 0 30
50
70
90
Figure 5. Effect of temperature over yield of the product Temperature (Degree)
110
GC Spectrum of 2-Benzylidene cyclohexanone at 80 °C
Apr-June 2014
Volume 2 Issue2
Page 25
T. Somanathan.et.al
www.ijfstonline.org
Calculation for percentage conversion of the product using the GC peak area Total Area of Peak A
%A
X 100 %
= Total Area of Peak A and Peak B 1.86 =
X 100 %
=
95.876 % (major peak )
1.94
Total Area of Peak B %B
X 100 %
= Total Area of Peak A and Peak B 0.08
= 4.
1.94
X 100 %
= 4.124 % (minor peak )
Conclusions In this work, a simple and low cost route was developed to synthesis MgO
nanoparticles with a high surface area, large size and uniformity by precipitation method. The MgO nanoparticles present excellent catalytic ability as a heterogeneous solid base catalyst in condensation reaction of benzaldehyde and cyclohexanone for 2-benzylidenecyclohexanone. A highly efficient and stable solid base catalyst which gives a high yield of 95.8% of 2-benzylidenecyclohexanone with in a short period of time. The temperature plays a vital role to increase the yield of the product Acknowledgement One of the Authors, T. Somanathan would like to thank the Department of Science and Technology (DST) for the award of Fast Track Young Scientist Award by providing financial support (SR/FT/CS-111/2011). References 1. Roelofs JCAA, Lensveld DJ, Dillen van AJ, Jong de KP. On the Structure of Activated Hydrotalcites as Solid Base Catalysts for Liquid-Phase Aldol Condensation. J Catal 2001; 203: 184 – 91.
Apr-June 2014
Volume 2 Issue2
Page 26
T. Somanathan.et.al
www.ijfstonline.org
2. Cota I, Chimentao R, Sueiras J, Medina F. The DBU-H2O complex as a new catalyst for aldol condensation reactions. Catal Commun 2008; 9: 2090 – 94. 3. Zhong L, Gao Q, Gao J, Xiao J, Li C. Direct catalytic asymmetric aldol reactions on chiral catalysts assembled in the interface of emulsion droplets. J Catal 2007; 250: 360 – 4. 4. Climent MJ, Corma A, Fomes V, Guil-Lopez R, Iborra S. Aldol Condensation on Solid Catalysts: A Cooperative Effect between Weak and Acid Base Sites. Adv Synth Catal 2002; 344: 1090 – 6. 5. Gokulakrishnan N, Raju Kumar, Randhir Kumar. Effective uptake of doxorubicin on ZnO nanoparticles: Future application in drug delivery system. International Journal of Frontiers of Science and Technology 2013; 1: 67 – 74. 6. Tang Y, Xu J, Gu X. Modified calcium oxide as stable solid base catalyst for Aldol condensation reaction. J Chem Sci 2013; 125: 313 – 20. 7. Sundrarajan M, Suresh J, Rajiv Gandhi R, A comparative study on antibacterial properties of MgO nanoparticles prepared under different calcination temperature. Digest Journal of Nanomaterials and Biostructures 2012; 7: 983 – 9. 8. Sundarrajan S, Ramakrishna S. Fabrication of nano-composite membranes from nanofibers and nanoparticles for protection against chemical warfare stimulants. J Mater Sci 2007; 42: 8400 – 7. 9. Kumar S, Azurdia JA, Laine RM. Synthesis of (MgO)x(Fe2O3)1-x nanoparticles via liquid feed flame spray pyrolysis. A non-stoichiometric spinel phase outside the normal phase diagram. J Ceramic Proc Research 2010; 11: 517522. 10. Pei L Z, Yin WY, Wang JF, Chen J, Fan CG, Zhang QF. Low temperature synthesis of magnesium oxide and spinel powders by a sol-gel process. Materials Research 2010; 13: 339 - 343. 11. Burton BB, Goldstein DN, George SM. Atomic Layer Deposition of MgO Using Bis(ethylcyclopentadienyl)magnesium and H2O. J Phys Chem C 2009; 113: 1939 - 1946. 12. Viswanatha R, Venkatesh TG, Vidyasagar CC, Nayaka A, Arch YJ. Preparation and Characterization of ZnO and Mg-ZnO nanoparticle. Appl Sci Res 2012; 4; 480 - 486. 13. Bohern CF, Huffman DR, Absorption and scattering of light by small particles, Wiley Interscience Publication, New York, 1983, Chapters 9-12. 14. Utamapanya S, Klabunde KJ, Schlup JR. Nanoscale metal oxide particles/clusters as chemical reagents. Synthesis and properties of ultrahigh
Apr-June 2014
Volume 2 Issue2
Page 27
T. Somanathan.et.al
www.ijfstonline.org
surface area magnesium hydroxide and magnesium oxide. Chem Mater 1991; 3: 175 – 81. 15. Raju V, Radhakrishnan R, Jaenicke S, Chuah GK. KF on γ-alumina: An efficient catalyst for the aldol condensation to pseudoionones. Catal Today 2011; 164: 139 – 42. 16. Chilcote DD, Scott CD. Mathematical analysis of normalization techniques used in chromatography. Anal Chem 1973: 45: 721–724
Apr-June 2014
Volume 2 Issue2
Page 28
