Phenol-rich Oil Research Articles

Catalytic conversion of the heavy fraction of bio-oil into phenol-rich oils using an Fe-carbon catalyst during straw pyrolysis

This study examines the catalytic cracking of the heavy fraction of bio-oil to produce phenol-rich oils, emphasizing the enhancement of biochar-based catalysts through the incorporation of metallic iron (Fe) species. Results indicate that the Fe-carbon catalyst significantly enhances the conversion of heavy oil constituents into phenolic compounds, increasing the relative content of phenolics from 41 % to over 76 %, compared to unenhanced co-pyrolysis, which primarily yielded methylphenols, phenol, 2-methylphenol, and 3-methylphenol. These findings suggest that the heavy fraction of bio-oil, typically abundant in macromolecular compounds, offers viable opportunities for the targeted production of phenolic oils utilizing Fe-carbon catalysts. The findings suggest a viable pathway for the conversion of bio-oil heavy fractions into valuable phenolic compounds, highlighting the potential for industrial applications and the optimization of biorefinery processes.

Pursuing the circularity of wind turbine blades: Thermochemical recycling by pyrolysis and recovery of valuable resources

Wind turbine blades (WTBs) are the primary waste generated by the wind energy industry and represent one of the major challenges associated with renewable energy from a disposal perspective. Therefore, it is necessary to develop recycling processes to address this environmental issue as circular economy strategies are implemented. This work investigates the technical feasibility of a combined thermochemical process to recover high-quality glass fibers from WTBs while optimizing the composition of the liquid and gaseous fractions. For this purpose, a thermal pyrolysis process in the range of 450–500 °C was studied in a laboratory-scale fixed-bed reactor, followed by thermal cracking of the vapors between 300 and 700 °C. The fixed bed reactor in which the pyrolysis was performed was also used to study a secondary thermochemical process under oxidizing conditions in order to remove residual exogenous organic compounds from the recovered fibers (RFs). For the sake of comparison, a muffle furnace was also used in this second stage. The results indicate that high yields of RFs can be recovered (75.8–77.5 wt%) and, depending on the temperature used in the cracking reactor, either valuable gas (up to 12.9 wt%) or phenol-rich oils (in the range of 8.8–18.7 wt%) can be produced. In addition, carbonaceous compounds can be completely cleaned of RFs after an oxidation process in the same pyrolysis unit, providing a highly versatile process. As an additional advantage, it is observed that after oxidation the RFs are functionalized. This work aims at creating a resource-efficient circular economy, specifically for waste generated from end-of-life renewable energy technologies such as wind turbines.

Bi-functional and bi-metallic catalytic solvo-hydrothermal liquefaction for upgrading hydrocarbon of phenol-rich oil from kraft black liquor lignin

This study primarily aimed to enhance the hydrocarbon of a solvo-hydrothermal liquefaction (S-HTL) process initially extracting phenolic-rich oil. To catalyze the current process, HZSM-5 zeolite with its modifications were applied to S-HTL. Ni2P was first introduced to zeolite forming bifunctional catalyst and further coating it with either Co, Mo, or Zn to create bimetallic catalyst. The analysis showed that the zeolite structure did not change after the modifications. The acid sites on the catalyst were found to be principally responsible for the hydrodeoxygenation upgrading the oil yield, biomass conversion, and hydrocarbon generation. Catalytic HTL also produced compounds not detected in non-catalytic S-HTL which appeared to be largely promoted by the catalyst with Ni2P. Additionally, oil output, biomass conversion, and hydrocarbon yield were all substantially increased by catalyst (supplemented by Mo) about 20 %, 5 %, and 15 %, respectively. Moreover, Mo-supplemented catalyst with pre-treatment could be used for 5 more cycles with insignificant oil conversion reduction. Overall, the study synthesized bi-functional and bi-metallic catalysts and applied it to S-HTL improving the yield of generated oil and increasing hydrocarbon production.

Lignin extraction from kraft black liquor and its conversion to phenol-rich oil by hydrothermal liquefaction process

This study exploited lignin from black liquor as feedstock in the hydrothermal liquefaction process. The operation conditions such as temperature, operation time, and solvent ratio (by adding ethanol) were explored, with temperature identified as the most significant parameter. The optimum condition generating the highest oil yield (58.9 %) was found at an operating temperature, time, and solvent ratio of 275 °C, 30 min, and 1:1 water-to-ethanol ratio, respectively. The extracted oil was further characterized, revealing phenolic-rich oil containing about 83.4 % phenol, which was dominated by guaiacol. The lignin-to-oil conversion was initiated by thermochemical degradation comprising a series of multiple chemical reactions. The overall process reduced sulfur, nitrogen, and oxygen content linked to reaction instability, favoring solid char yield. The resulting higher heating value of the extracted phenol-rich oil was about 27.8 kJ/g, almost twice that of the raw black liquor only having 14.1 kJ/g.

Effect of Catechin on the Formation of Polycyclic Aromatic Hydrocarbons in Camellia oleifera Oil during Thermal Processing.

Polycyclic aromatic hydrocarbons (PAHs) in oil are affected by many factors, including temperature, time, and PAHs precursors. Phenolic compounds, as beneficial endogenous components of oil, are often associated with the inhibition of PAHs. However, studies have found that the presence of phenols may lead to increased levels of PAHs. Therefore, this study took Camellia oleifera (C. oleifera) oil as the research object, in order to study the effect of catechin in the formation of PAHs under different heating conditions. The results showed that PAH4 were generated rapidly during the lipid oxidation induction period. When the addition of catechin was >0.02%, more free radicals were quenched than generated, thus inhibiting the generation of PAH4. ESR, FT-IR, and other technologies were employed to prove that when the catechin addition was <0.02%, more free radicals were produced than quenched, causing lipid damage and increasing PAHs intermediates. Moreover, the catechin itself would break and polymerize to form aromatic ring compounds, ultimately leading to the conclusion that phenolic compounds in oil may be involved in the formation of PAHs. This provides suggestions for the flexible processing of phenol-rich oil to balance the retention of beneficial substances, and for the safe control of hazardous substances in real-life applications.

Selective Production of Phenol-Rich Bio-Oil From Corn Straw Waste by Direct Microwave Pyrolysis Without Extra Catalyst.

We report a sustainable strategy to cleanly address biomass waste with high-value utilization. Phenol-rich bio-oil is selectively produced by direct pyrolysis of biomass waste corn straw (CS) without use of any catalyst in a microwave device. The effects of temperature and power on the yield and composition of pyrolysis products are investigated in detail. Under microwave irradiation, a very fast pyrolysis rate and bio-oil yield as high as 46.7 wt.% were obtained, which were competitive with most of the previous results. GC-MS analysis showed that temperature and power (heating rate) had great influences on the yield of bio-oil and the selectivity of phenolic compounds. The optimal selectivity of phenols in bio-oil was 49.4 area% by adjusting the operating parameters. Besides, we have made detailed statistics on the change trend of some components and different phenols in bio-oil and given the law and reason of their change with temperature and power. The in situ formed highly active biochar from CS with high content of potassium (1.34 wt.%) is responsible for the improvement of phenol-rich oils. This study offers a sustainable way to fully utilize biomass waste and promote the achievement of carbon neutrality.

Lignin Characterization and Catalytic Pyrolysis for Phenol-Rich Oil with TiO2-Based Catalysts

In this study, the chemical structure of corn straw lignin and the catalytic pyrolysis behavior at 350–650 °C in a fixed bed was investigated, with TiO2-based catalysts (load Cu, Fe, and Mo) respec...

Co-production of phenolic oil and CaO/char deoxidation catalyst via catalytic fast pyrolysis of phenol-formaldehyde resin with Ca(OH)2

Phenol-formaldehyde (PF) resin was widely used in industry, it would cause an adverse effect on the environment if without applicable treatments of resin wastes. Triglycrides (e.g., soybean oil) were abundant in the nature, but cannot be used directly as engine fuel. The deoxygenation of triglycrides was necessary for producing liquid fuel similar to that derived from petroleum. Herein, PF resin was used to co-produce phenolic-rich oil and CaO/char deoxygenation catalyst by catalytic fast pyrolysis with Ca(OH)2. The CaO/char was used as catalyst to catalytic deoxygenation of soybean oil via catalytic fast pyrolysis process. It was found that Ca(OH)2 changed the thermal decomposition behaviours of PF resin dramatically and promoted the cracking reactions to form more monophenol compounds. The optimal conditions for producing phenol-rich oil (containing 9.1% aromatic hydrocarbons and 82.8% phenols, GC–MS area fraction) with 37.3% yield were 650 °C and 5.0% Ca(OH)2 catalyst. Meanwhile, the total carbon yield of targeted phenols reached 33.7%. Solid residue (char) was further pyrolyzed at 800 °C for producing CaO/char catalyst that helped to reduce the bio-oil oxygen content from 14.4% to 2.4% in the pyrolysis of soybean oil. The peak area % of aromatic hydrocarbons in the oil was 86.8%, and indicated it could be used as gasoline. Phenolic oil from PF resin and aromatic hydrocarbons-rich oil from vegetable oil are easily produced by fast pyrolysis with calcium catalyst.

Evaluation of RuxNi1-x/SBA-15 catalysts for depolymerization features of lignin macromolecule into monomeric phenols

The bimetallic catalysts were prepared by a wetness impregnation method with different molar ratios of Ru and Ni (RuxNi1-x, x = 0.2, 0.4, 0.6, 0.8, and 1.0) on mesoporous silica SBA-15. Soda lignin (SL) was directly depolymerized to phenol-rich oil fraction (lignin-oil) over bimetallic catalysts under supercritical ethanol. 2D-HSQC-NMR demonstrated that representative interunit linkages such as β-O-4, β-5, and β-β were considerably degraded during depolymerization process by thermal reaction. Phenol was mainly produced from SL with other phenolic compounds such as guaiacol, 4-ethylphenol, 4-methylguaiacol, 4-ethylguaiacol, and syringol. This study revealed that the chemical properties of lignin-oil were clearly affected by the physicochemical properties of bimetallic catalysts. By increasing the amount of hydrogen binding sites and the acidity of the catalyst, the yields of lignin-oil, total phenols, and phenol increased while that of char decreased. In particular, acidic sites in bimetallic catalysts have a significant effect on the formation of phenol. The yields of total monomeric phenols and phenol were largest with the Ru0.6Ni0.4 catalyst (12.7 wt%, and 4.7 wt%, respectively).

Predicting fuel properties using chemometrics: a review and an extension to temperature dependent physical properties by using infrared spectroscopy to predict density

Although the use of chemometric methods to predict fuel quality properties has received wide attention over the past three decades, as seen from the review included with this article, no studies were found about predicting temperature dependent properties of fuels. Since our research is focused on determining thermodynamic properties, rather than quality properties, taking temperature dependencies into account became even more important. To determine if accurate predictions could be obtained over a range of temperatures, the densities of over 300 fuel samples (mostly narrow boiling range oil fractions, considered here as pseudocomponents) were measured and predicted. An alternative fuel (a phenol-rich oil shale oil) was studied because the property prediction methods developed for conventional petroleum samples often give poor results for this and other alternative fuels. The temperature dependence of density for these fuel samples was modelled using a linear equation based on the density at 20°C and the slope of the density-temperature relationship. Support vector regression was used to predict these parameters for each sample from its infrared spectrum. Then these parameters were used to predict the densities at other temperatures. Densities spanned the range from 0.713 to 1.088g/cm3, and the root mean squared error of the predicted values was 0.004660g/cm3, which is a relative error of less than 1%. In addition to the experimental portion, a literature review is included, which contains an assessment of the accuracy of chemometric methods for predicting many fuel properties.

Comparison of degradation features of lignin to phenols over Pt catalysts prepared with various forms of carbon supports

Soda lignin separated from wheat straw was successfully depolymerized to produce a phenol-rich oil fraction over various carbon-supported platinum (Pt) catalysts.

Conversion of Lignin to Phenol-Rich Oil Fraction under Supercritical Alcohols in the Presence of Metal Catalysts

Asian lignin was directly depolymerized to phenol-rich oil fraction (lignin-oil) over Pt/C, Pd/C, Ru/C, and Ni/C under supercritical alcohols. Ethanol and Pt/C (E-Pt) proved to be an excellent combination for producing large amounts of lignin-oil (77.4 wt %) with the smallest amount of char (3.7 wt %). Lignin-oil mainly consisting of monomeric phenols, and higher molecular phenolic was subjected to several chemical analyses. Elemental analysis indicated that hydrodeoxygenation and hydrogenation primarily occur during lignin depolymerization. 1H-/2D-HSQC-NMR and GPC analysis revealed that the Mw of lignin-oil remarkably is lower than that of Asian lignin, which is clear evidence of β-O-4 and β–β bond cleavages. The top four main monomeric phenols in lignin-oil were 4-ethylphenol, guaiacol, 4-ethylguaiacol, and syringol, for which the sum was mostly produced in E-Pt (41.8 mg/g of lignin) with the highest selectivity (38.3%). With increasing catalyst dosage, we observed that excessive catalyst caused side re...

Extraction of cardanol and phenol from bio-oils obtained through vacuum pyrolysis of biomass using supercritical fluid extraction

The feasibility of extraction of phenol rich oil from the bio-oils obtained through pyrolysis of cashew nut shells and sugarcane bagasse is studied. The extraction rate of phenol rich oil using CO 2 as a supercritical fluid is discussed. Operating parameters are optimized for the maximum concentration of phenol and cardanol. Higher yield of oil (50% by weight) along with higher concentration of phenols and cardanol by present method is found encouraging. The experiments were conducted in the pressure range of 120–300 bar, the temperature range of 303–333 K and the mass flow rate range of 0.7–1.2 kg/h. The process parameters are optimized to maximize the yield of extracts and its contents of phenols and substituted phenols from sugarcane bagasse pyrolysis oil. The oil samples obtained at various operating parameters are analyzed by Gas Chromatograph–Mass Spectroscopy (GC–MS) and Fourier Transform Infra-Red Spectroscopy (FTIR).

Bacterial susceptibility to and chemical composition of essential oils from Thymus kotschyanus and Thymus persicus.

Susceptibility of Escherichia coli, Staphylococcus aureus, Bacillus subtilis, Klebsiella pneumonia, and Pseudomonas aeroginosa to the essential oils extracted from two varieties of Thyme, i.e., Thymus kotschyanus Boiss. and Hohen. and Thymus persicus L. at preflowering and flowering stages were studied. The disk diffusion method was used to evaluate the zone of microbial growth inhibition at various concentrations of the oils. Minimal inhibitory concentration and minimal bactericidal concentration of the oils were determined and compared with each other. The oils from the above plants were found to be strongly bactericidal with that of T. kotschyanus being more effective. T. kotschyanusand T. persicus oils analyzed by gas chromatography (GC) and GC/mass spectrometry (MS) lead to identification of 33 and 26 components, respectively. The profile of the oil components from T. persicuswas similar to that of T. kotschyanus in almost all of the compounds but at different concentrations. The major components of T. kotschyanus oil before and at the flowering stages were carvacrol (35.06, 22.75%), thymol (26.60, 16.52%), gamma-terpinene (7.81, 0.34%), gamma-terpinene (4.34, 0%), borneol (2.29, 4.52%), myrcene (0.26, 12.65%), thymolquinone (0, 11.39%), nerol (0, 6.10%), and beta-caryophyllene (0, 5.54%), respectively, and those of T. persicus at the same stages were carvacrol (38.96, 27.07%), thymol (6.48, 11.86%), P-cymene (7.51, 10.16%), gamma-terpineol (0, 9.51%), nerol (15.66, 9.41%), gamma-terpinene (6.11, 6.51%), and thymol acetate (5.29, 5.30%), respectively. The contribution of oil components to its antibacterial property is discussed. High aromatic compound content of the phenol-rich oils seems to account for strong antibacterial activity.

Olive Oils Rich in Natural Catecholic Phenols Decrease Isoprostane Excretion in Humans

This study was undertaken to evaluate, in humans, the antioxidant activity of olive oil phenolics, namely hydroxytyrosol and oleuropein aglycone that share an orthodiphenolic (catecholic) structure. Human volunteers were administered olive oil samples containing increasing amounts of an olive oil phenolic extract that was characterized by gas-chromatography/mass spectrometry. The administration of phenol-rich oils was dose-dependently associated with a decreased urinary excretion of 8-iso-PGF2α, a biomarker of oxidative stress. Also, a statistically significant negative correlation between homovanillyl alcohol (HValc, hydroxytyrosol's major metabolite, formed through the COMT system) and F2-isoprostanes excretion was found. Thus, the administration of oil samples with increasing, albeit low, concentrations of orthodiphenolic compounds, namely hydroxytyrosol and oleuropein aglycone, results in a dose-dependent reduction in the urinary excretion of 8-iso-PGF2α. The statistically significant negative correlation between 8-iso-PGF2α and HValc urinary concentrations suggests that this metabolite better reflects the in vivo activities of hydroxytyrosol.