Liquid-phase dehydration of propylene glycol using solid-acid catalysts

Courtney, Timothy D.; Nikolakis, Vladimiros; Mpourmpakis, Giannis; Chen, Jingguang G.; Vlachos, Dionisios G.

doi:10.1016/j.apcata.2012.09.034

Cited by 28 publications

(18 citation statements)

References 53 publications

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“…10%), and S PDO and S BDO were also low (1). This indicates that Lewis acids and bases are not effective for dehydration of diols under the present conditions, which is consistent with the results reported by Courtney et al 22 In contrast, Brønsted acid catalysts H-Y 9 and H-MOR 16 gave enhanced conversions of PDO and BDO. Particularly over H-ZSM-5 28, H-Beta 26, phosphotungstic acid and H 2 SO 4 , the diol conversions were over 60%.…”

Section: Catalyst Screeningsupporting

confidence: 92%

See 1 more Smart Citation

Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

Jiang

Yang

et al. 2017

AIChE Journal

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Ethylene glycol (EG), synthesized from biomass, frequently contains refractory 1,2‐propanediol (PDO) and 1,2‐butanediol (BDO). Selective removal of PDO and BDO was realized herein by catalytic dehydration to form volatile aldehydes, ketones, and acetals. Various acidic and basic catalysts were screened under a range of conditions for the conversion of a mixture containing 73 wt % EG, 20 wt % PDO, and 7 wt % BDO. Over H‐Beta 26 zeolite, the most selective catalyst among tested, PDO and BDO conversions reached 99.1 and 99.3%, respectively, after 4 h reaction at 453 K, with separation factors over 2. The activation energies for EG, PDO, and BDO dehydration were ca. 99.3, 69.9, and 54.0 kJ/mol, respectively, accounting for the high reactivity of PDO and BDO. The dehydration largely proceeded in the micropores of H‐Beta and depended on the number of strong Brønsted acid sites, but excessively strong acid sites enhanced the polymerization of EG. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4032–4042, 2017

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Section: Catalyst Screeningsupporting

confidence: 92%

“…Notably, vicinal diols can be dehydrated over various catalysts, including solid acids, acidic oxides, and alkaline oxides, to form aldehydes through the pinacol rearrangement . EG, PDO, and BDO are all vicinal diols, but differing from EG, PDO, and BDO contain terminal methyl or ethyl groups.…”

Section: Introductionmentioning

confidence: 99%

Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

Jiang

Yang

et al. 2017

AIChE Journal

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“…6). Lower levels of carbonyls were generated from mixtures of the carriers, notably 25% PG:75% VG, likely due to multiple factors including mass and heat transfer as well as rate-determining dehydration kinetics associated with the mixture composition (Courtney et al 2012). Because PG has a lower boiling point as well as a higher saturation vapor pressure than VG, PG is easier to atomize (Suppl.…”

Section: Discussionmentioning

confidence: 99%

Electronic cigarette-generated aldehydes: The contribution of e-liquid components to their formation and the use of urinary aldehyde metabolites as biomarkers of exposure

Conklin

Ogunwale

Chen

et al. 2018

Aerosol Science and Technology

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Electronic cigarettes (e-cigarette) have emerged as a popular electronic nicotine delivery system (ENDS) in the last decade. Despite the absence of combustion products and toxins such as carbon monoxide (CO) and tobacco-specific nitrosamines (TSNA), carbonyls including short-chain, toxic aldehydes have been detected in e-cigarette-derived aerosols up to levels found in tobacco smoke. Given the health concerns regarding exposures to toxic aldehydes, understanding both aldehyde generation in e-cigarette and e-cigarette exposure is critical. Thus, we measured aldehydes generated in aerosols derived from propylene glycol (PG):vegetable glycerin (VG) mixtures and from commercial e-liquids with flavorants using a state-of-the-art carbonyl trap and mass spectrometry. To track e-cigarette exposure in mice, we measured urinary metabolites of 4 aldehydes using ULPC-MS/MS or GC-MS. Aldehyde levels, regardless of abundance (saturated: formaldehyde, acetaldehyde >> unsaturated: acrolein, crotonaldehyde), were dependent on the PG:VG ratio and the presence of flavorants. The metabolites of 3 aldehydes - formate, acetate and 3-hydroxypropyl mercapturic acid (3-HPMA; acrolein metabolite) -- were increased in urine after e-cigarette aerosol and mainstream cigarette smoke (MCS) exposures, but the crotonaldehyde metabolite (3-hydroxy-1-methylpropylmercapturic acid, HPMMA) was increased only after MCS exposure. Interestingly, exposure to menthol-flavored e-cigarette aerosol increased the levels of urinary 3-HPMA and sum of nicotine exposure (nicotine, cotinine, trans-3’-hydroxycotinine) relative to exposure to a Classic Tobacco-flavored e-cigarette aerosol. Comparing these findings with aerosols of other ENDS and by measuring aldehyde-derived metabolites in human urine following exposure to e-cigarette aerosols will further our understanding of the relationship between ENDS use, aldehyde exposure and health risk.

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“…During e-cigarette use, propylene glycol and glycerol can react by dehydration and oxidation pathways to yield methyl glyoxal (201,232,246); glyceraldehyde (60); propylene oxide (154); glycidol (190); dioxolanes (69,76,125); and oxalic, lactic, and pyruvic acids (156,257), as shown in Figs. 10 and 11.…”

Section: Potential Biomarkers Of E-cigarette Usementioning

confidence: 99%

Biomarkers of exposure to new and emerging tobacco delivery products

Schick

Blount²,

Jacob

et al. 2017

American Journal of Physiology-Lung Cellular and Molecular Phys

108

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Accurate and reliable measurements of exposure to tobacco products are essential for identifying and confirming patterns of tobacco product use and for assessing their potential biological effects in both human populations and experimental systems. Due to the introduction of new tobacco-derived products and the development of novel ways to modify and use conventional tobacco products, precise and specific assessments of exposure to tobacco are now more important than ever. Biomarkers that were developed and validated to measure exposure to cigarettes are being evaluated to assess their use for measuring exposure to these new products. Here, we review current methods for measuring exposure to new and emerging tobacco products, such as electronic cigarettes, little cigars, water pipes, and cigarillos. Rigorously validated biomarkers specific to these new products have not yet been identified. Here, we discuss the strengths and limitations of current approaches, including whether they provide reliable exposure estimates for new and emerging products. We provide specific guidance for choosing practical and economical biomarkers for different study designs and experimental conditions. Our goal is to help both new and experienced investigators measure exposure to tobacco products accurately and avoid common experimental errors. With the identification of the capacity gaps in biomarker research on new and emerging tobacco products, we hope to provide researchers, policymakers, and funding agencies with a clear action plan for conducting and promoting research on the patterns of use and health effects of these products.

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Liquid-phase dehydration of propylene glycol using solid-acid catalysts

Cited by 28 publications

References 53 publications

Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

Electronic cigarette-generated aldehydes: The contribution of e-liquid components to their formation and the use of urinary aldehyde metabolites as biomarkers of exposure

Biomarkers of exposure to new and emerging tobacco delivery products

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