Catalytic Conversion Of Glycerol Research Articles

Selective synthesis of oxygenated fuel derivative from microwave assisted acetalization of glycerol: Optimization and mechanistic investigations

Glycerol contains 52 wt% oxygen content, therefore unable to be directly used as fuel due to its poor combustion ability. Thus, the catalytic conversion of glycerol into various oxygen-containing fuel additives is grabbing more attention nowadays. This work provides a novel, sustainable, and eco-friendly method for synthesizing heterogeneous acid carbon catalysts from pearl millet cob (PMC) waste. The hydrothermal carbonization process was carried out at different temperatures to fabricate the series of sulfonated pearl millet cob (SPMC) catalysts. XRD, FT-IR, SEM-EDS, XPS, BET, TGA, and CHNSO analyses were performed to characterize fabricated catalysts. The synthesized catalyst, SPMC-70 (catalyst synthesized at 70 °C temperature), possesses OH, COOH, and SO3H functional groups and a significant total acid density (2.03 mmol/g) with 37 m2/g surface area. The SPMC catalysts were employed for the microwave-assisted acetalization reaction of glycerol with acetone for solketal production. The optimization process was carried out using various reaction parameters, including catalyst dosage (2–6 wt.%), reaction temperature (30–60 °C), glycerol to acetone (GL to AC) molar ratio (1:3–1:9), and reaction time (4–13 min). The SPMC-70 catalyst showed the highest catalytic activity among all the synthesized catalysts and provided 99.11 ± 0.3 % GL conversion with 100 % selectivity of solketal under optimal reaction conditions. Additionally, the recyclability test was performed, and it found that the best catalyst was reusable for up to five reaction cycles. These results showed the effectiveness of carbon-based heterogeneous acid catalysts in deriving a fuel additive, solketal.

New Trends in Catalytic Conversion of Glycerol

Glycerol is the core byproduct in the production of biodiesel [...]

Catalytic conversion of glycerol. A review of process kinetics and catalytic reactors

Glycerol, the by-product of the Biodiesel manufacturing from vegetal and animal fats, is an important bio-resource, which can be transformed into a significant number of valuable products, by catalytic, enzymatic, or biological technologies. This paper presents a review of published studies on the kinetics of the main catalytic transformations of glycerol into valuable products, along with information regarding the catalytic reactors experienced or proposed for these transformations. In the kinetic description of the glycerol catalytic transformations, the most used are the rate expressions based on the Langmuir-Hinshelwood-Hougen-Watson (LHHW) theory and the empirical ones, of the power law type. The published results are evidencing that, in addition to the general technical and economic advantages, the liquid phase continuous processes of glycerol transformation are more efficient, ensuring, in many cases, a higher selectivity of the transformation and a slower deactivation of the catalyst.

Separation of lactic acid and by-products obtained by catalytic conversion of glycerol using high-performance liquid chromatography

Lactic acid is an attractive raw material in synthesizing many products. A new method for quantifying glycerol, lactic acid, and the by-products (pyruvaldehyde) obtained in this reaction was developed using high-performance liquid chromatography (HPLC) with a refractive index detector (HPLC-RI) in a column (300 � 7.7 mm, 8 �m) using H2SO4 0.001 M + 10% ACN (organic modifier) as mobile phase (0.6 mL min�1). This method indicated outstanding linearity for glycerol and lactic acid concentration from 0.6 to 6.6 g L�1 (coefficient of determination (R�) = 0.9912 and 0.9961, respectively) and accuracy between 98.33 and 100.00%. From this, it was possible to conclude that the method is applicable and concise for separating the primordial products in this reaction.

Catalytic conversion of glycerol and co-feeds (fatty acids, alcohols, and alkanes) to bio-based aromatics: remarkable and unprecedented synergetic effects on catalyst performance.

Glycerol is an attractive bio-based platform chemical that can be converted to a variety of bio-based chemicals. We here report a catalytic co-conversion strategy where glycerol in combination with a second (bio-)feed (fatty acids, alcohols, alkanes) is used for the production of bio-based aromatics (BTX). Experiments were performed in a fixed bed reactor (10 g catalyst loading and WHSV of (co-)feed of 1 h−1) at 550 °C using a technical H-ZSM-5/Al2O3 catalyst. Synergistic effects of the co-feeding on the peak BTX carbon yield, product selectivity, total BTX productivity, catalyst life-time, and catalyst regenerability were observed and quantified. Best results were obtained for the co-conversion of glycerol and oleic acid (45/55 wt%), showing a peak BTX carbon yield of 26.7 C%. The distribution of C and H of the individual co-feeds in the BTX product was investigated using an integrated fast pyrolysis-GC-Orbitrap MS unit, showing that the aromatics are formed from both glycerol and the co-feed. The results of this study may be used to develop optimized co-feeding strategies for BTX formation.

Cobalt oxide promoted tin oxide catalysts for highly selective glycerol acetalization reaction

The excessive production of glycerol as a by-product in the biodiesel industry increased environmental problems due to issues related to storage and waste management. Therefore, the catalytic conversion of glycerol into value-added chemicals is of great interest. Using heterogeneous catalysis, we investigated the selective acetalization of glycerol to solketal (C6H12O3), an additive used in fuel production, using acetone in the presence of bimetallic oxide catalysts (Co3O4/SnO2). The catalytic materials were fully characterized using physical and chemical techniques such as nitrogen sorption (BET), power X-ray diffraction, (p-XRD), temperature-programmed desorption, (TPD-CO2 and TPD-NH3), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). An attempt to correlate the acidic sites to the catalyst activity was not successful. However, it is important to note that, the reaction gave conversions greater than 90% and maximum selectivity to the formation of the solketal. Optimum conditions were investigated and showed the most active catalyst to be Co3O4/SnO2 (75:25) with conversion above 90%. Catalyst stability evaluations showed that Co3O4/SnO2 (50:50) is very stable and can be recycled up to 6 catalytic cycles with minor catalyst loss.

Catalytic Conversion of Glycerol into Aromatic Hydrocarbons, Acrolein, and Glycerol Ethers on Zeolite Catalysts

The effect of the nature of zeolite catalysts H-ZSM-5, H-BETA, and SAPO-34 on the activity and selectivity in the conversion of glycerol into aromatic hydrocarbons, acrolein, and oxygenates (various glycerol ethers) was studied. H-ZSM-5 was found to be the most effective catalyst for the conversion of glycerol into aromatic hydrocarbons and mono-, di-, and trisubstituted glycerol ethers with methanol and isobutylene. These products are effective gasoline additives increasing its octane number. Zeolite SAPO-34 shows the lowest activity in aromatization and alkylation reactions; the main product formed on this catalyst was acrolein.

Bio-additive fuels from glycerol acetalization over metals-containing vanadium oxide nanotubes (MeVOx-NT in which, Me = Ni, Co, or Pt)

The biodiesel production has led to a drastic surplus of glycerol and catalytic conversion of glycerol into value-added products is of great industrial importance. Thus, the acetalization of glycerol with ketone or aldehydes allows the glycerol transformation into bio–additive fuels. In this work, metals-containing vanadium oxides nanotubes (MeVOx NT in which, Me = Co, Pt or Ni) have been synthesized with additional internal porosity and tested in the acetalization of glycerol with acetone (AG) for valuable biofuels production. The catalysts showed remarkable performances in the AG reaction. Furthermore, by variation of the composition, catalyst loading and temperature and using distinct substrates (butyraldehyde, furfuraldehyde and benzaldehyde), NiVOxNT is active, being very selective to solketal and reciclable for 4 times in the AG reaction. On the contrary, pure VOx NT easily deactivated due to the structure agent removal during the reaction, which promote the collapse of the tubular structure. The CoVOxNT and PtVOxNT catalysts did not exhibit such a stable structure and easily deactivated in the reaction due to leaching of the metals oxides during the AG.

Catalytic Conversion of Glycerol in the Presence of Ni/F–Al2O3 Catalyst

Catalytic Conversion of Glycerol in the Presence of Ni/F–Al2O3 Catalyst

Acetalization of glycerol with acetone over Co[II](Co[III]xAl2−x)O4 derived from layered double hydroxide

The rapid rising production of biodiesel has led to a drastic surplus of glycerol, and catalytic conversion of glycerol into value-added products is of great importance. Among of which, solketal, derived from the acetalization of glycerol and acetone, is an important chemical and fuel additive. In this work, a series of solid acid Co[II](Co[III]xAl2−x)O4 catalysts were prepared via controlled decomposition of layered double hydroxide and used in the acetalization of glycerol with acetone. It was found that Co[II](Co[III]xAl2−x)O4 is highly active and selective for this reaction under mild condition. The selectivity of solketal reached 98.6% with a 69.2% conversion of glycerol at 130 °C and 3.0 h over Co[II](Co[III]1.25Al0.75)O4. Characterizations results indicated that the performance of Co[II](Co[III]xAl2−x)O4 depended mainly on the acidity of Co[II](Co[III]xAl2−x)O4, and the conversion of glycerol increased with the amount of strong acid sites.

Catalytic dehydration of glycerol to acrolein over M2.5H0.5PW12O40 (M = Cs, Rb and K) phosphotungstic acids: Effect of substituted alkali metals

Catalytic conversion of glycerol into value-added chemicals, particularly acrolein via acid-catalyzed dehydration route has received much attention due to the potential uses of acrolein. This work reports the synthesis of various alkaline metal substituted phosphotungstic acid (H3PW12O40, HPW) catalysts, namely M2.5H0.5PW12O40 (M=Cs, Rb and K) using a controlled precipitation method. A systematic structural, morphology, and chemical characterization were conducted using various analytical techniques. XRD studies revealed that the incorporation of alkaline metals in H3PW12O40 leads to decreased crystallite size and enhanced lattice strain. N2 adsorption–desorption studies show that the specific surface area of H3PW12O40 is significantly improved from 5 to 82 (K2.5H0.5PW12O40), 103 (Rb2.5H0.5PW12O40), and 94m2/g (Cs2.5H0.5PW12O40). XRD, Raman, and FT-IR studies confirm the Keggin structure of all the alkaline metal substituted HPW catalysts. The acidity strengths estimated by NH3-TPD analysis were obtained in the following order: H3PW (2654.91μmole/g)>K2.5H0.5PW (1060.10μmole/g)>Rb2.5H0.5PW (762.08μmole/g)>Cs2.5H0.5.5PW (461.81μmole/g). Although alkaline metal substituted H3PW12O40 catalysts exhibit higher specific surface area and smaller crystallite size compared to parent H3PW12O40 low glycerol conversions were found for substituted H3PW12O40 catalysts. As well, the parent H3PW12O40 catalyst shows an excellent acrolein selectivity (95%) which is much higher than that of Cs2.5H0.5.5PW (81.9%) and very close to the selectivities obtained over Rb2.5H0.5PW (95.1%) and K2.5H0.5.5PW (95.6%) catalysts. The catalytic performance of H3PW12O40andM2.5H0.5PW12O40 materials is directly proportional to their acidic strengths, indicating that the catalyst acidity is a key factor for achieving better results in glycerol dehydration.

Recent advancements in catalytic conversion of glycerol into propylene glycol: A review

ABSTRACTThe renewability of bio-glycerol has made it an attractive platform for the production of diverse compounds. Selective hydrogenolysis of glycerol to propylene glycol (PG) is one of the most promising routes for glycerol valorization, since this compound is an important chemical intermediate in a number of applications. In this article, advancements in the catalytic conversion of glycerol into propylene glycol are reviewed, which include advances in process development, effects of preparation and activation methods on catalytic activity and stability, and the performance of various types of catalysts. The feasibility of using bio-hydrogen and the challenges of utilizing crude glycerol for glycerol hydrogenolysis are also discussed.

Sulfated Pillared Clay as Catalyst in Glycerol Esterification with Caprylic Acid

Sulfated pillared clay (AP-S) was tested in the catalytic conversion of glycerol by esterification reaction with caprylic acid (octanoic acid, OA). The clay was treated with concentrated fuming sulfuric acid. The presence of sulfur as well as an increase in the acidity of the solid demonstrate the suitability of the sulfatation process. The best conditions for the esterification reaction with OA were OA:glycerol molar ratio 8:1, 423 K and 5 wt% catalyst. Total glycerol conversion was achieved after 5 h and yield of 27, 43 and 30 % respectively for monocarpylin, dicaprylin and tricaprylin were obtained.

Enhancing the biodiesel manufacturing process by use of glycerin to produce hyacinth fragrance

Oxidized and sulfonated-activated carbons (AC) were tested in the catalytic conversion of glycerol by acetalization reactions. The solids were treated with concentrated nitric acid and/or fuming sulfuric acid (AC, AC-N, AC-S, and AC-NS). The presence of sulfur and an increase in the acidity of the solids demonstrate the suitability of the oxidation as well as the sulfonation process, especially in the sample treated with concentrated nitric acid and fuming sulfuric acid (AC-NS). The best catalyst for the reaction of glycerol acetalization with phenylacetaldehyde was AC-NS, with a phenylacetaldehyde conversion of 95 % after 90 min at 383 K and selectivity of 88 and 12 %, respectively, to dioxolane and dioxane. These products can be used as hyacinth fragrance flavoring compounds. Furthermore, a contribution of homogeneous catalysis in these systems was not identified. Thus, we identified a possibility of glycerol conversion, a biodiesel by-product, into value-added products by suitable catalysts produced from activated carbons.

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

AbstractConversion 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/Al2O3) 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. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

Catalytic performance of Pd–Ni bimetallic catalyst for glycerol hydrogenolysis

Catalytic conversion of glycerol from biodiesel production to value-added chemicals and fuels is actually of great interest for industrial chemical research. Bimetallic catalysts are confirmed superior to monometallic catalysts in terms of catalytic activity and selectivity for glycerol hydrogenolysis. Accordingly, a series of Pd–M (M = Fe, Co, Ni, Cu, Zn) bimetallic catalysts were prepared in this work via coprecipitation to investigate the promoting effect of Pd. The relationship between the catalytic performance and metal-support interaction was also discussed. Through the catalyst screening, Pd–Ni bimetallic catalyst exhibited moderate activity and the highest selectivity towards ethylene glycol. At 493 K and hydrogen pressure of 6.0 MPa, the glycerol conversion and selectivity of ethylene glycol reached 89% and 22% respectively. XRD and TEM patterns showed that the Pd nanoparticles with an average size of ∼4 nm were uniformly dispersed in the supports. H2-TPR revealed that the reduction temperatures of metal oxides were significantly decreased by the introduction of Pd component. XPS curves indicated that unique performance of the Pd–Ni bimetallic catalyst might be attributed to the formation of Pd–Ni alloy. And the required metal-support interaction was assumed responsible for the cleavage of C–C bond and generation of ethylene glycol. In the end, hydrogenolysis reactions for the main products of glycerol conversion were carried out over Pd–Ni catalyst to explore the possible reaction pathways for glycerol hydrogenolysis.

Products and production routes for the catalytic conversion of seed oil into fuel and chemicals: a comprehensive review

With the depletion of fossil resources, there is a need to find alternative resources of fuels and chemicals. The use of renewable feedstock such as those from seed oil processing is one of the best available resources that have come to the fore-front recently. This paper critically analyzes and highlights major factors in the biodiesel industry, such as seeds oil composition, production methods, properties of biodiesel, problems and potential solutions of using vegetable seed oil, the composition, quality and effective utilization of crude glycerol, the catalytic conversion of glycerol into possible fuels and chemicals.

Conversion of Glycerol into Useful Chemicals over Iron Oxide-based Catalyst

Catalytic conversion of glycerol with iron oxide-based catalysts was investigated for the production of useful chemicals. The catalytic reaction was carried out in a fixed-bed flow reactor at 623 K under atmospheric pressure. Useful chemicals such as allyl-alcohol, propylene and ketones were produced from glycerol through two main pathways: formation of allyl alcohol and propylene (Pathway I), and formation of hydroxyacetone and acrolein (Pathway II). Hydroxyacetone in Pathway II is easily converted into carboxylic acids followed by ketonization to form acetone, methyl ethyl ketone and pentanone. An increase in the W/F (weight ratio of catalyst to feedstock) value allowed the consecutive reactions to progress and the final products were 24 mol%-carbon of propylene and 25 mol%-carbon of ketones. Moreover, addition of alkaline metals to the catalyst increased the yield of allyl alcohol. This study demonstrates the production of useful chemicals from glycerol (crude glycerol and reagent glycerol). The effects of catalyst composition and experimental conditions on these yields are discussed, based on investigations of the reaction pathways and mechanisms.

Sulfonated niobia and pillared clay as catalysts in etherification reaction of glycerol

Sulfonated niobia (HY-340 CBMM) and pillared clay (Fluka) were tested in the catalytic conversion of glycerol by etherification reactions. The solids were treated with concentrated fuming sulfuric acid (AS100 and NS100), and a 30% aqueous solution of this acid (AS30 and NS30). Both the presence of sulfur and the increase in the acidity of the solids demonstrate the suitability of the sulfonation process, especially in samples treated with concentrated fuming sulfuric acid. The best catalyst for the reaction of etherification with tert-butyl alcohol was AS100, with a glycerol conversion of 95% after 5h at 393K and yield of 60.3, 33.2 and 5.4%, respectively for mono-tert-butyl-glycerol (MTBG), di-tert-butyl-glycerol (DTBG) and tri-tert-butyl-glycerol (TTBG).

Propylene from Renewable Resources: Catalytic Conversion of Glycerol into Propylene

Propylene, one of the most demanded commodity chemicals, is obtained overwhelmingly from fossil resources. In view of the diminishing fossil resources and the ongoing climate change, the identification of new efficient and alternative routes for the large-scale production of propylene from biorenewable resources has become essential. Herein, a new selective route for the synthesis of propylene from bio-derived glycerol is demonstrated. The route consists of the formation of 1-propanol (a versatile bulk chemical) as intermediate through hydrogenolysis of glycerol at a high selectivity. A subsequent dehydration produces propylene.