Chemical Engineering Journal 176–177 (2011) 42–48 Contents lists available at ScienceDirect Chemical Engineering Journal jo u r n al hom epage: www.elsevier.com/locate/cej Evaluation of gold on alumina catalyst deactivation dynamics during -pinene isomerization Yu.S. Solkina a , S.I. Reshetnikov a , M. Estrada b , A. Simakov c , D.Yu. Murzin d , I.L. Simakova a,∗ a Boreskov Institute of Catalysis, Novosibirsk 630090, Russia b Posgrado de Física de Materiales de CICESE-UNAM, Ensenada, B.C., 22860, Mexico c Centro de Nanociencias y Nanotecnología, Universidad Nacional Autónoma de México, Ensenada, B.C., 22860, Mexico d Åbo Akademi University, PCC, Turku/Åbo, Finland a r t i c l e i n f o Article history: Received 23 December 2010 Received in revised form 16 March 2011 Accepted 30 March 2011 Keywords: Isomerization -Pinene Camphene Deactivation modeling Gold catalyst UV–vis in situ a b s t r a c t Synthesis of camphene is an important step in an industrial process for camphor production from - pinene. Compared to conventional way of -pinene to camphene transformation over acid-hydrated TiO 2 , gold on alumina catalyst was found to provide -pinene isomerization conversion up to 99.9% and selectivity 60–80% making this catalyst very promising from an industrial viewpoint. However, deacti- vation of gold catalyst might be a serious obstacle for real industrial implementation. According to TPO and UV–vis-mass in situ it was shown that deactivation is caused by adsorption of hydrocarbons on the gold species. The dynamics of catalyst deactivation during -pinene isomerization was presented based on a so-called “separable” deactivation model assumption. Effects of isomerization temperature, initial -pinene concentration and gas atmosphere on catalyst deactivation with time-on-stream were inves- tigated experimentally and correlated with the proposed deactivation function. The results showed that the -pinene concentration was the major factor governing the deactivation of Au/-Al 2 O 3 catalyst under substrate-feeding conditions. When the -pinene concentration was controlled at a relatively low level such as 0.4 vol.%, especially in hydrogen atmosphere, the total deactivation rate was negligible. An equa- tion of the reaction rate taking into account the catalyst deactivation was suggested making prediction of deactivation behavior in -pinene conversion at different initial concentrations. © 2011 Elsevier B.V. All rights reserved. 1. Introduction The attention of the world scientific community is increasingly focused on environmental protection and efficient use of natural resources. A huge number of scientific publications on biomass transformation into valuable commercial chemicals have appeared recently [1,2]. Terpenes, extracted from biomass, such as -pinene, are inexpensive renewable raw materials that are widely used in the synthesis of fine chemicals [3–5]. Currently design of the new catalytic routes starting from biore- newables and different from the traditional chemical synthesis routes is one of the key issues of sustainable development [6]. Synthesis of camphene is an important step in an industrial pro- cess of -pinene isomerization to camphor, which is a valuable substrate for the pharmaceutical and perfumery industry [7,8]. The conventional way to transform -pinene to camphene is to perform catalytic conversion over acid-hydrated TiO 2 resulting in camphene yield from 35% to 50%. The reaction rate over TiO 2 is ∗ Corresponding author. E-mail address: simakova@catalysis.ru (I.L. Simakova). rather low and industrial interest is in finding a catalyst which possesses much higher activity and selectivity [9,10]. In our pre- vious work it was demonstrated that Au/-Al 2 O 3 catalyst is rather active in the vapour-phase -pinene isomerization to camphene with conversion 99.9% and very high selectivity of about 60–80% [11]. Although in initial reaction time Au catalyst is more active and selective than TiO 2 it dramatically deactivates over the course of the reaction that might be a serious obstacle for an industrial implementation. The main objective of the present work is to study dynamics of Au/-Al 2 O 3 catalyst deactivation in isomerization of -pinene to camphene by evaluation of the effects of isomerization tem- perature, initial -pinene concentration and gas atmosphere on camphene yield with time-on-stream. 2. Experimental 2.1. Catalytic set-up Vapour-phase isomerization of -pinene was carried out under continuous flow conditions at atmospheric pressure using a solu- tion of -pinene in n-octane as the initial reaction mixture and H 2 1385-8947/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.cej.2011.03.106