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Browsing by Author "Pang, Yutong"

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    Enabling Selective Dehydration of Methyl Lactate to Acrylates
    (2022-05) Pang, Yutong
    Dehydration of biomass-derived methyl lactate over NaY zeolite to acrylic acid and methyl acrylate is a promising route for the sustainable synthesis of acrylates. For commercial viability of the renewable chemistry, improvement of dehydration selectivity is necessary from the baseline performance of 60 to 90%. In the proposed reaction mechanism, dehydration occurs on the sodium acid sites, but side reactions occur on the in situ generated Brønsted acid sites (BAS) on the NaY catalyst. Introduction of a BAS-specific titrant can suppress side reactions and improve dehydration selectivity. While higher basicity favors stronger BAS adsorption and higher dehydration selectivity, steric limitations hinder BAS binding in the form of internal diffusion limitations and local steric interactions. Based on titrant basicity and steric limitations, multifunctional amines were demonstrated to afford the highest performance reported to date with a dehydration selectivity of 96% and a yield of 92%, exceeding the desirable values for commercial viability.
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    Supporting data for "Catalysis-in-a-Box: Robotic Screening of Catalytic Materials in the Times of COVID-19 and Beyond"
    (2020-05-29) Kumar, Gaurav; Bossert, Hannah; McDonald, Dan; Chatzidimitriou, Anargyros; Ardagh, Alexander M; Pang, Yutong; Lee, ChoongSze; Tsapatsis, Michael; Abdelrahman, Omar A; Dauenhauer, Paul; hauer@umn.edu; Dauenhauer, Paul, J; Dauenhauer Research Group
    The emergence of a viral pandemic has motivated the transition away from traditional, labor-intensive materials testing techniques to new automated approaches without compromising on data quality and at costs viable for academic laboratories. Reported here is the design and implementation of an autonomous micro-flow reactor for catalyst evaluation condensing conventional laboratory-scale analogues within a single gas chromatograph (GC), enabling the control of relevant parameters including reactor temperature and reactant partial pressures directly from the GC. Inquiries into the hydrodynamic behavior, temperature control, and heat/mass transfer were sought to evaluate the efficacy of the micro-flow reactor for kinetic measurements. As a catalyst material screening example, a combination of four Brønsted acid catalyzed probe reactions, namely the dehydration of ethanol, 2-propanol, 1-butanol, and the dehydra-decyclization of 2-methyltetrahydrofuran on a solid acid HZSM-5 (Si/Al 140), were carried out in the temperature range 403-543 K for the measurement of apparent reaction kinetics. Product selectivities, proton-normalized reaction rates, and apparent activation barriers were in agreement with measurements performed on conventional packed bed flow reactors. Furthermore, the developed micro-flow reactor was demonstrated to be about ten-fold cheaper to fabricate than commercial automated laboratory-scale reactor setups and is intended to be used for kinetic investigations in vapor-phase catalytic chemistries, with the key benefits including automation, low cost, and limited experimental equipment instrumentation.