Catalysis of Organic..

Bianchi, Borzatta, Poluzzi and Vaccari 339ExperimentalVarious commercial heterogeneous catalysts have been investigated: 1)oxides = γAl 2 O 3 (Sasol, D), SiO 2 (Engelhard, USA), ZrO 2 (Mel-Chemicals, UK);2) zeolite = T4480 (Süd-Chemie, D); 3) clays = Bentonite de Cabanas andEsmectita EMV351 (TOLSA, E), K 306F (United Catalyst, USA) Granosil 750JF, Mega Dry and 20/50 LVM (Süd-Chemie Inc., USA), Attagel 40 (Engelhard,USA); 4 ) acid treated clays = F20 (Engelhard, USA), KSF, Tonsil CO 610G(Süd-Chemie, D). 2,5-Dimethyl-2,5-hexandiol (DEMD), 2,5-dimethyl-2,4-hexadiene (TMBD), and CH 3 OH had purity ≥ 99% and were used without anyfurther purification. The vapour phase tests were carried out using 9 g of catalyst(30-40 mesh) in a stainless steel reactor (i.d. 1”, length 50 cm), inserted in anelectric oven controlled by a J thermocouple, operating at atmospheric pressureand in the 270-310 °C temperature range. The absence of axial profiles wasdetermined by a J thermocouple sliding inside a 1/8” stainless steel tube insertedin the catalytic bed. The feed was a solution of 2,5-dimethyl-2,5-hexandiol(DMED) in CH 3 OH (from 2.0 to 2.8 M) introduced by a Labflow 2000 HPLCpump (LHSV range = 0.46-1.15 h -1 ) in a N 2 flow, regulated by a mass-flowmeter.The catalysts were first heated at 550°C for 4.5 h under a 200 mL/min flow ofN 2 /air mixture (62:38) and afterwards at 290°C in-situ for 18 h under a 180mL/min flow of N 2 . In each test, the products were collected for 4 h (after 1 hnecessary to reach steady state activity) by condensing them in a trap at roomtemperature, followed by two traps cooled at 0°C and analysed off-line using aHewlett-Packard gas chromatograph, equipped with FID and a wide bore HP1column (length 30 m, i.d. 0.53 mm, and film width 1.25 μm). The catalyst-8060YieldKSFTonsil CO 610 GBentonite de CabanasEsmectita EMV 35140SiO2ZrO2Granosil750 JFMega Dry20T-44800Figure 2. Yield in TMBD in the preliminary screening tests. (Cat. = 9 g; T = 270°C; P = 0.1 MPa; Feed = 2.8 M DMED/CH 3 OH solution in N 2 flow; LHSV =0.46 h -1 [12].