The selective detection of crystalline cellulose in biomass was demonstrated with sum-frequency-generation (SFG) vibration spectroscopy. SFG is a second-order nonlinear optical response from a system where the optical centrosymmetry is broken. In secondary plant cell walls that contain mostly cellulose, hemicellulose, and lignin with varying concentrations, only certain vibration modes in the crystalline cellulose structure can meet the noninversion symmetry requirements. Thus, SFG can be used to detect and analyze crystalline cellulose selectively in lignocellulosic biomass without extraction of noncellulosic species from biomass or deconvolution of amorphous spectra. The selective detection of crystalline cellulose in lignocellulosic biomass is not readily achievable with other techniques such as XRD, solid-state NMR, IR, and Raman analyses. Therefore, the SFG analysis presents a unique opportunity to reveal the cellulose crystalline structure in lignocellulosic biomass.

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Methane non-oxidative coupling to ethylene was investigated on Mo C/[B]ZSM-5 catalyst at 923 K and atmospheric pressure. In contrast to Mo C/[Al]ZSM-5 catalysts for methane aromatization, this material exhibits very high ethylene selectivity (>90 %) and low aromatics (benzene and naphthalene) selectivity. The much weaker Brønsted acidity of [B]ZSM-5 leads to a slow rate of ethylene oligomerization. The stability of the catalyst is greatly enhanced with 93 % of the initial reaction rate remaining after 18 h of time on stream. In-situ UV/VIS spectra indicate that prior to carburization, mono/binuclear Mo oxides are initially well dispersed onto the zeolite support. Mo carbides clusters, formed during carburization with methane, appear similar to clusters formed in [Al]ZSM-5, as indicated by the X-ray Absorption Spectroscopy (XAS) data.

The effect of temperature (633-723 K), pressure (10-60 bar) and weight hourly space velocity (WHSV) (400-1500 g C5 g cat À1 h À1 ) on the conversion of n-pentane on H-[Al]ZSM-5 type catalysts has beeninvestigated. Catalyst properties were tested using a packed-bed laboratory microreactor and reaction products were analyzed via online gas chromatography. 5-25% pentane conversion was observed at a pressure of 40 bar and temperatures in the range of 633-723 K. Reactant consumption rate approached saturation kinetics at pressures above 30 bar (B14% conversion, 673 K). At 40 bar and 673 K, increasing WHSV (400-1500 g C5 g cat À1 h À1 ) resulted in a reduction in pentane conversion (26-10%). In all cases, propane and butane were the major products, followed by heavier C 6+ compounds and other lighter products (C 1 -C 4 paraffins and olefins). Propane carbon selectivity increased from 24% at 633 K to 34% at 723 K, while butane carbon selectivity (B40%) was nearly constant. An inverse relationship between the production of C 6+ and light products was observed with changes in reaction conditions. The carbon selectivity to C 6+ compounds increased from 20% at 10 bar to 27% at 60 bar and decreased from 28% at 633 K to 18% at 723 K. At all reaction conditions, the observed product distribution can be explained as the result of fast bimolecular reactions, including hydride transfer and alkylation.