Please cite this article in press as: S.K. Sharma, et al., J. Mol. Catal. A: Chemical (2009), doi:10.1016/j.molcata.2009.01.020 ARTICLE IN PRESS G Model MOLCAA-7423; No. of Pages 7 Journal of Molecular Catalysis A: Chemical xxx (2009) xxx–xxx Contents lists available at ScienceDirect Journal of Molecular Catalysis A: Chemical journal homepage: www.elsevier.com/locate/molcata The multi-step reactions for the synthesis of C 8 aldehydes and alcohol from propene in a single pot using an eco-friendly multi-functional catalyst system: Kinetic performance for parametric optimization Sumeet K. Sharma a,b , Ram S. Shukla a,∗ , Parimal A. Parikh b , Raksh V. Jasra a,1 a Discipline of Inorganic Materials and Catalysis, Central Salt and Marine Chemicals Research Institute (Council of Scientific and Industrial Research, CSIR), G.B. Marg, Bhavnagar – 364 021, Gujarat, India b Department of Chemical Engineering, S.V. National Institute of Technology, Surat – 395 007, Gujarat, India article info Article history: Received 14 October 2008 Received in revised form 26 December 2008 Accepted 13 January 2009 Available online xxx Keywords: Multi-phase reaction kinetics Hydroformylation Aldol condensation Multi-functional catalyst Hydrotalcite abstract Kinetics of multi-step reactions including hydroformylation, aldol condensation and hydrogenation was carried out in a single pot for optimization of the reaction parameters for the synthesis of C 8 aldehydes and alcohol from propene using an eco-friendly multi-functional heterogeneous catalyst system [HF/HT] where [HF] = rhodium complex, HRh(CO)(PPh 3 ) 3 and [HT] = hydrotalcite, Mg 1-x Al x (OH 2 ) x+ (CO 3 2- ) x/n ·mH 2 O. The catalyst [HF/HT] was synthesized by impregnation of [HF] onto the surface of [HT]. In the typical catalytic experiments conducted in a 100mL high pressure reactor under the employed reaction conditions: propene = 10 atm, CO = 5 atm, H 2 = 15 atm, [HF/HT] = 700 mg, HT/HF ratio = 7, Mg/Al molar ratio of [HT] = 3.5, aldol temperature = 250 ◦ C, reaction time = 12 h, agitation speed = 1000 rpm, and in 50 mL toluene as a solvent, 68.4 × 10 -3 M of 2-ethylhexanol with 18% selectivity was achieved. The rates of reactions were determined by analyzing the amounts of products formed at different time using gas chromatography. Kinetics of the various reactions were performed in detail by investigating the effect of reaction parameters such as Mg/Al molar ratio of [HT] at aldol temperature 150 and 250 ◦ C, amount of [HT] and [HF] complex, aldol temperature, partial pressure of CO and H 2 on the rates of formation of products namely, 2-ethylhexanol, 2-ethylhexanal, 2-ethylhexenal, butanals and butanols. The rates of reactions were found to be influenced by all these studied parameters. On increas- ing these parameters, the rates of formation of the products and their further conversions in single pot were favored. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Synthesis of C 8 aldehydes and alcohol from propene is an impor- tant reaction for production of these chemicals at commercial scale. C 8 aldehydes and alcohol (aldol products) like 2-ethylhexanal and 2-ethylhexanol are valuable intermediates for the production of dioctylphthalate, other plasticizers, coatings, adhesives, lubricants, alkyd resins, fine and specialty chemicals [1]. Commercially, syn- thesis of C 8 aldol derivatives from propene is a three steps process in which first step is the hydroformylation of propene to butanals using rhodium-based catalyst [1]. The second step is the aldol con- densation of the obtained n-butanal in the presence of strong liquid base KOH or NaOH, used in stoichiometric amounts for the produc- ∗ Corresponding authors. Tel.: +91 278 2567760; fax: +91 278 2566970. E-mail addresses: rshukla@csmcri.org (R.S. Shukla), rakshvir.jasra@ril.com (R.V. Jasra). 1 Present address: R&D Centre, VMD, Reliance Industries Limited, Vadodara 391 346, Gujarat, India. tion of 2-ethylhexenal [2–3]. The hydrogenation of 2-ethylhexenal is carried out in third step using palladium or copper based catalyst using fixed bed reactor [4–7]. The existing commercial processes for the synthesis of C 8 aldol derivatives are multi-steps processes using hazardous liquid base KOH/NaOH in stoichiometric amounts. These processes involve the problems like handling of strong liq- uid NaOH or KOH, separation and disposal of spent KOH or NaOH which require post-synthesis work-up and corrosion of reaction vessel. These processes are not eco-friendly also. A huge amount of spent liquid base gets generated during the formation of the product from aldol condensation in homogeneous conditions. It is estimated that approximately, 1.0–1.5tons of spent base solutions are gen- erated for every 10tons of product formed in homogeneous aldol condensation [8]. To overcome the drawbacks of the commercially employed processes, a novel approach has been reported previously to combine all the steps into a single pot by using multi-functional heterogeneous catalyst system [HF/HT] prepared by impregnation of HRh(CO)(PPh 3 ) 3 [HF] complex on the surface of a solid base hydrotalcite; (Mg 1-x Al x (OH 2 )) x+ (CO 3 2- ) x/n ·mH 2 O) [HT] [9–12]. This multi-functional heterogeneous catalyst system [HF/HT] has shown 1381-1169/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.molcata.2009.01.020