Applied Catalysis A: General 469 (2014) 267–274 Contents lists available at ScienceDirect Applied Catalysis A: General j ourna l h om epage: www.elsevier.com/locate/apcata Structural investigations of porous MgCl 2 –2-butanol molecular adduct as support for olefin polymerization K.S. Thushara a,b , T.G. Ajithkumar c , P.R. Rajamohanan c , Chinnakonda S. Gopinath a,b,d,∗,1 a Catalysis Division, CSIR – National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India b Academy of Scientific and Innovative Research, CSIR – National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India c Central NMR Facility, CSIR – National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India d Center of Excellence on Surface Science, CSIR – National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411 008, India a r t i c l e i n f o Article history: Received 15 May 2013 Received in revised form 24 August 2013 Accepted 3 October 2013 Available online 12 October 2013 Keywords: MgCl2 Molecular adduct NMR Ziegler–Natta catalyst Polyolefin Heterogeneous catalysis a b s t r a c t A new heterogeneous Ziegler–Natta (Z–N) catalyst support material, MgCl 2 ·4(CH 3 CH(OH)CH 2 CH 3 ) (Mg2BuOH) has been synthesized. 2-Butanol, a linear, secondary alcohol was chosen for the generation of an active MgCl 2 support which results in a Z–N catalyst with TiCl 4 . Significant feature of this work is the formation of rod shaped molecular adduct with highly porous character. Adduct material is characterized by XRD, TG-DTA, Raman spectroscopy, solid-state NMR and SEM. Activity of the Z–N catalyst supported on Mg2BuOH for ethylene polymerization is comparable with that of commercially available heterogeneous Z–N catalyst. However, there is scope to improve the activity by optimizing textural properties. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Discovery of MgCl 2 supported Ziegler–Natta (Z–N) catalyst for olefin polymerization lead to a huge progress in the polyolefin industry [1–5]. Heterogeneous Z–N system consists of TiCl 4 as active catalyst component, MgCl 2 based molecular adduct act as support, R 3 Al (R = methyl, ethyl, isobutyl) as co-catalyst. Generally, in heterogeneous catalysis, support material plays a significant role in the catalytic activity. However, as a support the role of MgCl 2 is critical in Z–N catalysis. Generation of active MgCl 2 is very impor- tant in heterogeneous Z–N olefin polymerization [6]. During the catalyst preparation process, the most important step will be the preparation of active MgCl 2 . A lot of modification has been done on MgCl 2 supported Z–N catalyst by varying the Lewis bases such as alcohols, ethers, esters etc. [7–25]. Chemical and mechanical meth- ods were employed for the generation of active MgCl 2 (-form) [26–28]. In chemical methods, both protic and non protic elec- tron donors are used as Lewis base to form molecular adduct, a ∗ Corresponding author at: Catalysis Division, CSIR – National Chemical Labora- tory, Dr. Homi Bhabha Road, Pune 411 008, India. Tel.: +91 20 2590 2043; fax: +91 20 2590 2633. E-mail addresses: cs.gopinath@ncl.res.in, csgopinaath@gmail.com (C.S. Gopinath). 1 http://nclwebapps.ncl.res.in/csgopinath/. precursor for active MgCl 2 [27,28]. Among the protic Lewis bases, ethanol is most extensively used for the formation of MgCl 2 ·xEtOH (x ≤ 6) molecular adduct [7–17]. Methanol, isopropanol, isobutanol, propanol, n-butanoletc are the few other aliphatic alcohols used for adduct preparation with MgCl 2 [12,29–31]. Molecular adducts of ethanol (MgEtOH) and isopropanol (MgiPrOH) and their catalytic activities have recently been investigated [17,29]. By changing the Lewis base from ethanol to isopropanol, an exponential increase in activity for ethylene polymerization has been observed for Z–N catalyst supported on MgCl 2 derived from MgiPrOH. Structurally, ethanol and isopropanol differ only by one carbon unit though the former one belongs to primary alcohol and the lat- ter to secondary alcohol. The size differences between these two alcohols are not so significant. An important point to be mentioned here is that, the Lewis bases used for the molecular adduct for- mation is not directly participating in the final catalytic activity since these alcohols were washed away during the catalyst prepa- ration. Indeed porosity generated at the time of incorporating TiCl x with molecular adduct is critical. Textural properties changes sig- nificantly for different alcohols present in the molecular adduct, since size, nature and number of alcohol molecules are different for each molecular adduct; however, alcohol removal lead to the exposure of different crystallographic planes of MgCl 2 and hence the change in catalytic activity. In the present study we have chosen a secondary alcohol, 2-butanol, to get more insights to the rela- tion between structure, size and nature of alcohol in the catalyst 0926-860X/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.apcata.2013.10.002