Catalytic conversion of glycerol to allyl alcohol; effect of a sacrificial reductant on the product yield

Applied Catalysis A: General

Dlugogorski

Kennedy

et al. 2016

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Alkaline preparation conditions engendered the zeolite with mesoporosity;Rubidium deposition enhanced allyl alcohol yield and decreased acrolein yield;Alkali post synthesis modification reduced the concentration of acid sites. AbstractUnder most reaction conditions studied, acrolein is reported as the primary product in the conversion of glycerol over zeolites. In such processes, acrolein forms at relatively high yields, with negligible allyl alcohol selectivity. In this contribution, we report the development of ZSM5-supported iron catalysts, modified by rubidium deposition, as stable materials for production of allyl alcohol from glycerol. Our results demonstrate a reduced rate of formation of acrolein over modified catalysts. Both unmodified and modified catalysts were analysed by inductively coupled plasma optical emission spectrometry, nitrogen adsorption, scanning electron microscope, X-ray diffraction, ammonia temperature programmed desorption, X-ray photoelectron spectroscopy and ultraviolet-visible spectroscopy. These techniques revealed that differences in product distribution and catalyst performance are due to the combined effects of iron loading, catalyst acidity and changes in the porosity of the catalyst.2

Section: Catalytic Measurementsmentioning

confidence: 99%

Zeolite-supported iron catalysts for allyl alcohol synthesis from glycerol

Applied Catalysis A: General

Dlugogorski

Kennedy

et al. 2016

“…Indeed, some hydrogen was detected in the gas phase, in concentrations of approximately 0.8% v/v. We have thus investigated the addition of reductants to the reaction and were able to increase selectivity to allyl alcohol . The addition of oxalic acid, a known reductant, doubled the yield of allyl alcohol over an unmodified iron catalyst.…”

Section: Resultsmentioning

confidence: 99%

Enhancing allyl alcohol selectivity in the catalytic conversion of glycerol; influence of product distribution on the subsequent epoxidation step

Harvey

Asia-Pacific J Chem Eng

Kennedy

et al. 2015

Self Cite

Conversion of glycerol to allyl alcohol in a flow reactor and subsequent conversion to glycidol in a batch reactor are discussed in this paper. To increase reaction selectivity in the glycerol to allyl alcohol reaction, the catalyst was modified with alkali metal salts. The treatment of the catalyst (Fe/Al 2 O 3 ) with potassium, caesium and rubidium salts enhanced the allyl alcohol yield when a 35 wt% glycerol solution was used as feed. Furthermore, the addition of organic reductants or hydrogen to the glycerol feed increased the allyl alcohol yield. Optimisation of allyl alcohol selectivity was achieved by a combination of alkali metal cation modifiers and the addition of reductants. The influence of acid, base and redox properties on selectivity is presented, focusing on the effect of these properties on product distribution. The effect of by-products from the conversion of glycerol to allyl alcohol on the epoxidation reaction was examined to identify the ideal reaction conditions for maximising the glycidol yield. Epoxidation of allyl alcohol by 30 wt% hydrogen peroxide was conducted in a batch reactor at 333K using titanium silicate-1 catalyst. Conversion of allyl alcohol was high for all conditions; however, hydrolysis of glycidol to glycerol reduces selectivity.

“…A 35 wt % glycerol aqueous solution and gas phase ammonia (3 %) were reacted over an alumina-supported iron catalyst. Details on catalyst preparation and composition are provided in previous publications [7,15]. The reaction was carried out with nitrogen as carrier gas and with a GHSV of approximately 1190 h -1 operating for 180 min at 340 °C and atmospheric pressure, in a reactor system described elsewhere [15].…”

Section: Methodsmentioning

confidence: 99%

“…Details on catalyst preparation and composition are provided in previous publications [7,15]. The reaction was carried out with nitrogen as carrier gas and with a GHSV of approximately 1190 h -1 operating for 180 min at 340 °C and atmospheric pressure, in a reactor system described elsewhere [15]. Once the catalytic experiments were terminated, the experimental setup was purged with nitrogen and allowed to cool to room temperature.…”

Section: Methodsmentioning

confidence: 99%

“…Our research group has recently published on the use of ammonia enhancing the formation of allyl alcohol from glycerol over an iron catalyst [15]. Product distribution in the liquid phase consists predominantly of allyl alcohol, acrolein, acetaldehyde, hydroxyacetone, carboxylic acids, 2,4-dimethyl-2-oxazoline-4-methanol, 2-(aminooxy)propanoic acid among others, with carbon dioxide, carbon monoxide, acrolein and acetaldehyde in the gas phase [15]. The formation of a solid product did not occur when ammonia was absent operating at the same reaction conditions, which suggests the involvement of the reactant gas in the polymerisation mechanism.…”

Section: Insights On the Mechanism Of Formation Of The Building Blockmentioning

confidence: 99%

See 1 more Smart Citation

Catalytic conversion of glycerol to polymers in the presence of ammonia

Chemical Engineering Journal

Gaikwad

Holdsworth

et al. 2016

Self Cite

In this contribution, the development of a process for the synthesis of potentially highly valuable polymeric products from the reaction of waste glycerol with ammonia is reported for the first time. The polymers were the result of a single step, continuous gas phase process, catalysed by an alumina-supported iron catalyst, operating under relatively mild reaction conditions. The solid product was characterised using 1D and 2D NMR spectroscopy, FTIR spectroscopy, qualitative chemical tests and elemental analysis. Characterisation revealed building blocks with unsaturated, amido and ester functionalities shaping a mixture of polymers. Nitrogen atoms were present in the main chain of the resultant polymers. NMR analyses of the polymer denotes the formation of structural defects such as unsaturation and branching; while the partial solubility of the polymer in solvents such as CDCl 3 and THF is indicative of the formation of cross-linked structures. Insights into the mechanism of formation of these functional groups were based on the liquid and gas phase product distribution. Polymers with chain structures similar to those synthesised in this work are currently manufactured from fossil fuels and are widely used in biomedical applications not 2 only because of their architecture but also due to their response to changes in pH and temperature.