J.A. de los Reyes

Selectivity to cumene in the alkylation of benzene with isopropanol on a MCM-41/γ-Al2O3 catalyst

Abstract Alkylation of benzene with isopropanol to produce cumene was investigated using a MCM-41 aluminosilicate as catalyst. The MCM-41/γ-Al 2 O 3 catalyst, activated by means of a liquid extraction method, mainly contained strong Lewis acid sites. After the activity of the composite catalyst was stabilized, it was observed that, in the isopropylation of benzene, cumene was the major product. The high cumene selectivity could be due to the low acid site concentration in the MCM-41 material, and the rapid diffusion of cumene in the broad channels of this mesoporous framework.

Para-selectivity in the alkylation of toluene with isopropanol on a MCM-41/γ-Al2O3 catalyst

Abstract Alkylation of toluene with isopropanol to produce isopropyltoluenes was investigated using a MCM-41 aluminosilicate as catalyst. The MCM-41/γ-Al2O3 catalyst presented mainly strong Lewis sties so that this material was activated by means of a liquid extraction method. It was observed that in the isopropylation of toluene, the isopropyltoluenes fraction contained more para isomer. This is due to the fact that MCM-41 materials contain relatively a few acid sites. In addition, the primary products of alkylation easily diffuse into the broad channels of this mesoporous framework.

Chemical vapor deposition of 6CuO·Cu2O films on fiberglass

Abstract To coat fiberglass with copper oxides, in particular with the paramelaconite structure 6CuO·Cu 2 O, we have used the chemical vapor deposition (CVD) procedure of a copper precursor. The deposition of copper oxides was done using a horizontal-flow reactor, 2,4-pentanedionate copper(II) as precursor and O 2 as carrier-reactant gas at several deposition temperatures. In order to establish a correlation between experimental parameters and the resulting copper species, as well as film quality, the samples that were produced, were evaluated using techniques such as X-ray diffraction (XRD), visible spectrophotometry, scanning electronic microscopy (SEM) and atomic force microscopy (AFM). The most important result is that 6CuO·Cu 2 O thin films are obtained over a short range of deposition temperatures. The film growth of this copper phase occurred in the [202] and [004] directions.

Hydrodeoxygenation of Phenol Over Sulfided CoMo Catalysts Supported on a Mixed Al2O3-TiO2 Oxide

Abstract In this work, the effect of the mixed Al2O3-TiO2 oxide (Al/Ti=2, named AT2) support on the support-metal interaction in oxide state, its influence on MoS2 dispersion and its impact on the hydrodeoxygenation of phenol reaction was studied. In contrast with CoMo/Al2O3 catalysts, the use of Al2O3-TiO2 as support tuned favorably the support-metal interaction, increasing the availability of easily reducible CoOX and MoOX species with octahedral coordination, which are recognized as precursors of the active phase. The lower support-metal interaction strength caused a decrease in the dispersion of MoS2 phase. Even so, the sulfided CoMo/AT2 catalyst reached 85 % higher catalytic activity in the hydrodeoxygenation of phenol than CoMo/Al2O3. These increases were explained in terms of the formation of a higher amount of active CoMoS phase, and it is consistent with the increased availability of cobalt promoter for the decoration of MoS2 edges. CoMo/AT2 catalyst was more resistant to inhibition by CS2 than CoMo/Al2O3 in direct deoxygenation route and hydrodeoxygenation of phenol.