Hydrodeoxygenation of 4-Propylguaiacol (2-Methoxy-4-propylphenol) in a Microreactor: Performance and Kinetic Studies

Abstract

Catalytic hydrodeoxygenation of 4-propylguaiacol, a model compound for lignin-derived components of pyrolysis oil, was performed in a packed-bed microreactor. The effects of various processing conditions were investigated using presulfided NiMo/Al 2 O 3 catalyst. The conversion of 4-propylguaiacol is highly influenced by temperature. Although many products were formed, 4-propylphenol predominated under the operating conditions selected with presulfided NiMo catalyst. External and internal mass-transfer resistances and heat-transfer resistance were investigated and found to be negligible. Reaction rate expressions were based on proposed reaction mechanisms using the Langmuir−Hinshelwood approach. Nonlinear regression was performed to obtain kinetic constants. The best-fitting rate equations were further validated by comparing experimental data obtained from an integral reactor with predictions obtained using the Runge−Kutta method based on the rate equations. A difference of less than 10% between the experimental data and the predicted data for the integral reactor was found.

Catalytic Transformation of Biomass Derivatives to Value‐Added Chemicals and Fuels in Continuous Flow Microreactors

“…Due to the strong shear force generated by centrifugal forces in the CCCS, liquid-liquid mixing is enhanced considerably, accelerating reactions with fast kinetics that are limited by mass transfer. [134] Typically, microreactors have been used for single liquid phase and biphasic (gas-liquid or liquid-liquid) catalytic transformation of biomass derivatives to valuable products using homogeneous or heterogeneous catalysts (e. g., the (biphasic) synthesis of furans from sugars, [135][136][137][138][139][140][141][142][143][144] (aerobic) oxidation, [144][145][146][147][148][149] and hydrogenation of biomass derivatives [144,[150][151][152][153] ). [126] Another intensified reactor configuration for multiphase (gasliquid or liquid-liquid) catalytic biomass transformation is the spinning disc reactor, consisting of a rotating disc around which fluids are fed.…”

“…HDO reaction performance is often expressed in the extent of HDO (amount of oxygen removed) and space time consumption (STC) of H 2 (amount of H 2 consumed per reaction time and catalyst weight). [153] Also here internal mass and heat transfer limitations could be neglected under the conditions used (200-450°C and 16.5-33 bar), allowing to accurately determine rate expressions in the microreactor for the development of a kinetic model. [152] Commercially available catalyst particles were modified by grinding and sieving to reduce particle size and facilitate their incorporation into the microreactor by gravitational filling.…”

“…Many reactions have potential for intensification in microreactors, [133] and they hold great promises for improving (certain types of) biomass transformations. [134] Typically, microreactors have been used for single liquid phase and biphasic (gas-liquid or liquid-liquid) catalytic transformation of biomass derivatives to valuable products using homogeneous or heterogeneous catalysts (e. g., the (biphasic) synthesis of furans from sugars, [135][136][137][138][139][140][141][142][143][144] (aerobic) oxidation, [144][145][146][147][148][149] and hydrogenation of biomass derivatives [144,[150][151][152][153] ). Furthermore, biodiesel synthesis by the (trans)esterification of triglycerides and fatty acids derived from plant oils, waste cooking oils and animal fats has been extensively studied in microreactors using inorganic [154][155][156] or enzymatic catalysts.…”

Alkylphenols to phenol and olefins by zeolite catalysis: a pathway to valorize raw and fossilized lignocellulose

“…The state of the art also provides the knowledge to demethoxylate such methoxylated (alkyl)phenols, yielding selectively the alkylphenol at high conversions (and methane or methanol, conversion C). [28][29][30][31][32][33][34][35][36][37][38] The high selectivity to lignin monomers using the ligninfirst strategy stands in great contrast to many other state-ofthe-art depolymerization techniques, such as pyrolysis, 39,40 base-catalyzed depolymerisation, 41,42 and hydrogenolysis. 43,44 The latter works yield, besides often substantial unwanted side products as char and light gases, a wide variety of up to 20 or more products, and a phenol yield limited to ca.…”

Hydrodeoxygenation of microalgae oil to green diesel over Pt, Rh and presulfided NiMo catalysts

“…In relation to that, microreactors provide ease of scale-up through the numbering-up approach, which have been demonstrated elsewhere [14,[25][26][27][28][29][30]. There is a dearth of experimental data in the literature on hydrodeoxygenation of microalgae oil, and our overall goal was to contribute reliable data that can be used in pilot studies in a prelude to industrial scale-up.…”