Please cite this article in press as: R. Vijaya Shanthi, et al., Hydrogenolysis of sorbitol over Ni supported on Ca- and Ca(Sr)-hydroxyapatites, Mol. Catal. (2017), https://doi.org/10.1016/j.mcat.2017.12.031 ARTICLE IN PRESS G Model MCAT-438; No. of Pages 8 Molecular Catalysis xxx (2017) xxx–xxx Contents lists available at ScienceDirect Molecular Catalysis journal homepage: www.elsevier.com/locate/mcat Hydrogenolysis of sorbitol over Ni supported on Ca- and Ca(Sr)-hydroxyapatites R. Vijaya Shanthi a,b , R. Mahalakshmy b , K. Thirunavukkarasu a,∗ , S. Sivasanker a,∗ a National Centre for Catalysis Research, I.I.T.-M., Chennai, 600 036, India b Department of Chemistry, Thiagarajar College, Madurai, 625 009, India a r t i c l e i n f o Article history: Received 23 August 2017 Received in revised form 20 December 2017 Accepted 20 December 2017 Available online xxx Keywords: Sorbitol hydrogenolysis Glycols Hydroxyapatite Sr-substitution Ni/hydroxyapatite a b s t r a c t Ca-hydroxyapatite (HAP) was synthesized with different morphologies, in needle (N), sphere (S) and rod (R) shapes. A partially Sr-substituted sample (Ca(Sr)-hydroxyapatite) with the stoichiometric com- position of Sr 0.6 Ca 9.4 (PO 4 ) 6 (OH) 2 , and possessing a rod shaped morphology was also hydrothermally synthesized (SrHAP-R). The samples were characterized by X-ray diffraction, Fourier-Transform infra-red spectroscopy (FT-IR), scanning and transmission electron microscopy (SEM and TEM), X-ray photoelec- tron spectroscopy (XPS) and surface area measurement. Nickel (6 wt%) was loaded on the samples by an impregnation method. Rod-shaped hydroxyapatite (HAP-R) was more crystalline than the others. FT-IR results showed characteristic bands for (PO 4 ) 3− and O H vibrations. XPS results indicated Ni to be in the 2+ state, and O 1s satellite features revealed a phosphoric oxide environment in all the samples. The catalytic activities of the Ni-containing samples were tested in the hydrogenolysis of sorbitol into ethy- lene and propylene glycols in an aqueous medium in a stirred high pressure reactor at different process conditions. The most active catalyst was Ni/SrHAP-R. The catalyst was reusable many times with only a minor activity loss. © 2017 Elsevier B.V. All rights reserved. Introduction Ca-hydroxyapatite (HAP; Ca 10 (PO 4 ) 6 (OH) 2 ) is an important member of the apatite family and has been investigated exten- sively for applications in medicine due to its similarity to the mineral component of bones and teeth enamel and its good bio- compatibility [1]. It has also been investigated for use in diverse applications as catalyst [2–5] and catalyst support [2,4,6,7], as sen- sor [8], in pollution-control [9,10] and in drug delivery [11]. A variety of techniques have been reported for the synthesis of HAP to obtain samples with desired particle size, morphology, porosity and substituents [12–21]. Moreover, the Ca 2+ cations of HAP can be substituted with Zn, Mg, Sr, La, Cd, Pb, Cu, and Fe ions.The substi- tution of ions into pure HAP alters the crystal structure to a degree, and causes changes in some of its properties, including thermal stability, phase stability, solubility and surface reactivity [22]. Sr is quantitatively incorporated into HAP where its substitution for Ca leads to a linear increase in the lattice constants due to the greater ionic radius of Sr. Sr-substituted HAP (Ca(Sr)-hydroxyapatites) has ∗ Corresponding authors. E-mail addresses: KThirunavukkarasu@gmail.com (K. Thirunavukkarasu), ssivasanker@yahoo.com (S. Sivasanker). also been reported to exhibit good thermal stability at high tem- peratures between 600 and 900 ◦ C [23]. Though petroleum derived hydrocarbons are presently the raw materials for a vast majority of industrial chemicals, biomass derived oxygenate intermediates are expected to replace these in the future for sustainability reasons [24,25]. To achieve the goal of transforming biomass into chemicals, suitable catalysts and pro- cesses will need to be developed. One route for the transformation of lignocellulosic biomass into chemicals involves the separation of cellulose, its break-down into intermediate platform chemicals like glucose and sorbitol, and their conversion into bulk chemicals like the widely used ethylene and propylene glycols. Many studies on the transformation of sorbitol into ethylene glycol (EG), propanediol (PD) and glycerol (G) have been reported over the years [26–35]. We had earlier reported studies on Ni, Pt and Ru supported on NaY, and Ni supported on fly ash [36–38]. Our studies have been directed towards the production of ethy- lene and propylene glycols. An examination of the literature reveals that different supported metal catalysts have been used in the hydrogenolysis of polyhydric alcohols, Ni and Ru being the most preferred metals, and SiO 2 , carbon, Al 2 O 3 and MgO being the sup- ports [26,30,31,32–34]. The reaction has also been found to proceed better in the presence of a basic promoter like an alkaline earth hydroxide, especially Ca(OH) 2 [27,30,35–39]. https://doi.org/10.1016/j.mcat.2017.12.031 2468-8231/© 2017 Elsevier B.V. All rights reserved.