Guaiacol Research Articles

Synthesis, characterization and antimicrobial activity studies of new heterocyclic azo dye derived from 2-amino- 4,5- dimethyl thiazole with some metal ions

A novel heterocyclic azo dye ligand 2-[2- (4,5-Dimethyl thiazolyl)azo]- 4-methoxy phenol (DMeTAMP) was prepared by coupling reaction between diazonium salt produced from diazonited 2-amino- 4,5- dimethyl thiazole with 4 –methoxy phenol . The structures of the azo dye ligand and the metal complexes were characterized by elemental microanalyses (C.H.N.S), molar conductance, 1 H and 13 C- NMR, UV–Vis spectroscopy , FT-IR spectroscopy, magnetic susceptibility, thermal analysis (TGA), FESEM , mass spectra and XRD diffraction studies. The results appeared that prepared complexes offered [1:2] metal- ligand ratios and the ligand behaved as a tridentate chelating .The compounds were also tested for their bioactive property such as antibacterial and antifungal . The antioxidant activities of the ligand and Mn(II) complex were examined by using the DPPH radical scavenging method the compounds prove exhibited antioxidant properties of scavenging free radicals. Moreover, the anticancer properties of synthesized azo dye ligand and Mn(II) complexes were carried out against Colon cancer cell (CaCo 2 ) cell lines by MTT assay and results revealed that the prepared compounds exhibited good anticancer property and are very promising candidates for future applications in anti-tumor drugs . The finding indicated that these compounds have special significance in the field of medicine and pharmacy.

Anxiety-related shifts in smell function in children and adolescents.

Anxious adults show changes in smell function that are consistent with a durable shift in sensitivity toward particular odorants and away from others. Little is known regarding the development of these changes, including whether they exist in youth, are stable during the transition from childhood to adolescence, and whether odorant properties (e.g. trigeminal features, hedonic valence) affect anxiety-related differences in detection. To address this, we measured smell detection thresholds to phenyl ethyl alanine (PEA), a rose-like odorant with little trigeminal properties, and guaiacol (GUA), a smoke-like odorant with high trigeminal properties. These thresholds were measured at baseline and after an acute stress challenge, the Trier Social Stress Tests, in 131 healthy youth (in 4th, 7th, and 10th grades, age 9-16 years) that reported normal to elevated levels of anxiety. At baseline, high anxious youth exhibited heightened sensitivity to GUA coupled with reduced sensitivity to PEA, as well as a further exaggeration of this bias with acute stress. Importantly, sex, age, and hedonic valence moderated the relationship between trait anxiety and sensitivity to both odorants. Smell function and its aberrations are often overlooked in the literature on biomarkers of stress and anxiety. Taken together with the extant literature, these findings suggest that greater attention is warranted to characterize potential novel olfactory therapeutic targets-across the lifespan.

A fluorimetric and colorimetric dual-signal sensor for hydrogen peroxide and glucose based on the intrinsic peroxidase-like activity of cobalt and nitrogen co-doped carbon dots and inner filter effect.

Herein, cobalt and nitrogen co-doped carbon dots (Co-N-CDs) were fabricated via a one-pot hydrothermal approach. The obtained Co-N-CDs displayed peroxidase-like activity and fluorescence properties. It could catalyze the oxidization of guaiacol (GA) in the presence of hydrogen peroxide (H2O2), and thus, resulted in color change, accompanied by a new absorption peak in 470 nm. Owing to the inner filter effect, the oxidized product of GA (known as 2-PQ) largely absorbed the Co-N-CD fluorescence which was excited at 380 nm. Such changes in absorbance and fluorescence intensity were H2O2 concentration-dependent. Specifically, H2O2 could be generated by glucose oxidase to catalyze the oxidation of glucose, and thus, a colorimetric and fluorimetric sensor for glucose was established with high selectivity and excellent sensitivity. After the optimization of experimental conditions, this colorimetric sensor has a good linear range from 2 to 100 μM for glucose and the detection limit was 1.16 μM. Besides, the linear relationship between the fluorescence quenching value (ΔF) and the glucose concentration (0.4-40 μM) was obtained with a detection limit of 0.18 μM. Meanwhile, the proposed sensor has also been successfully applied for glucose detection in human serum samples, and the results were consistent with those of the standard method.

Phenol-derived products from fast pyrolysis of organosolv lignin

Lignin is the largest aromatic bio-polymer feedstock with a huge potential of being refined for aromatic chemical platform and building block. Organosolv process for lignin extraction has a low impact on the environment due to its low chemical requirement, the absence of sulfur, and as it is more practical for chemical recovery. Therefore, refinement of extracted lignin to valuable molecular compounds such as purified lignin and its derivative is the key success for biorefinery industry. In this study, sugarcane bagasse from a local sugar manufacturer in Thailand, noted as BG-lignin, was selected as feedstock for lignin extraction using ethanol and water. The chemical composition of this lignin was slightly different than that of commercially available organosolv lignin, noted as Comm-OS-lignin, in that BG-lignin has more combustible constituents (volatile organic compounds and fixed carbon) of 96.14% and low ash content of 0.09%. The chemical structure of BG-lignin contains a higher number of aliphatic hydrocarbon and aliphatic hydroxy side chains than Comm-OS-lignin, as confirmed by the FT-IR and 1H-NMR analyses. The study on fast pyrolysis of lignin, using Py-GCMS technique, found 2, 3-dihydrobenzofuran as a major constituent at any tested pyrolysis temperature. H-unit, G-unit, and S-unit are distributed in resemble fraction with a H∕G∕S ratio of 1∕1∕0.7 and 0.8∕1∕1 for Comm-OS-lignin and BG-lignin, respectively, at pyrolysis temperature of 400–600 °C, except for H-unit which was enhanced at 700 °C to 28.82% of Comm-OS-lignin and 29.66% of BG-lignin. At a temperature of 400–600 °C, phenolic selectivity of pyrolyzed products, mainly methoxy phenol (Ph-OCH3) and alkylated phenol (R-Ph-OCH3), was done. A higher pyrolysis temperature of 700 °C led to the elimination of aromatic side group and is more favorable in alkyl phenol (R-Ph) and phenol selectivity. However, reduction of the phenolic compound was observed with a higher temperature due to thermal fragmentation of the C–C linkage in the aromatic structure. Products selectivity related to lignin feedstock and pyrolysis temperature could be applied as a conceptual guideline for conducting further study of chemical upgrading process to obtain high-value biochemical products.

Total Phenolic Content of Methanol Extract from Buni Fruits (Antidesma bunius L.) Water

Buni Fruit Water was extracted with methanol solvent using Ultrasound technology at a temperature of 50°C for 45 minutes. Total Phenolic Content contained in the methanol extract of buni fruits water is 67 mg / g in GAE. The results of interpretation using GCMS obtained three phenolic compounds, namely 3-(Hydrazinomethyl) Phenol, 5 Allyl-2 Methoxy Phenol and 3 (3,5-di-Tertier Butyl, 4-Hydroxyphenyl) Propionic Acid. IR Spectrum analysis results obtained aromatic and OH group as a marker of the presence of phenolic compounds. These results indicate that the Buni fruit water can be developed as functional food.

Chitosan-Grafted Halloysite Nanotubes-Fe3O4 Composite for Laccase-Immobilization and Sulfamethoxazole-Degradation.

A surface-engineered nano-support for enzyme laccase-immobilization was designed by grafting the surface of halloysite nanotubes (HNTs) with Fe3O4 nanoparticles and chitosan. Herein, HNTs were magnetized (HNTs-M) by a cost-effective reduction-precipitation method. The synthesized HNTs-M were grafted with 0.25%, 0.5%, 1%, and 2% chitosan (HNTs-M-chitosan), respectively. Synthesized HNTs-M-chitosan (0.25%), HNTs-M-chitosan (0.5%), HNTs-M-chitosan (1%) and HNTs-M-chitosan (2%) were linked with glutaraldehyde (GTA) for laccase immobilization. Among these formulations, HNTs-M-chitosan (1%) exhibited the highest laccase immobilization with 95.13% activity recovery and 100.12 mg/g of laccase loading. The optimized material was characterized thoroughly by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM) analysis. The immobilized laccase (HNTs-M-chitosan (1%)-GTA-Laccase) exhibited higher pH, temperature, and storage stabilities. The HNTs-M-chitosan (1%)-GTA-Laccase possesses excellent reusability capabilities. At the end of 10 cycles of the reusability experiment, HNTs-M-chitosan (1%)-GTA-Laccase retained 59.88% of its initial activity. The immobilized laccase was utilized for redox-mediated degradation of sulfamethoxazole (SMX), resulting in 41%, 59%, and 62% degradation of SMX in the presence of 2,2′-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), guaiacol (GUA), and syringaldehyde (SA), respectively. Repeated SMX degradation (57.10% after the sixth cycle) confirmed the potential of HNTs-M-chitosan (1%)-GTA-Laccase for environmental pollutant degradation. Thus, we successfully designed chitosan-based, rapidly separable super-magnetic nanotubes for efficacious enhancement of laccase biocatalysis, which can be applied as nano-supports for other enzymes.

Positive phosphorous effect during co-processing of pyrolysis bio-oils and S-content model compounds over sulfide NiMo/P/HMS-Al catalysts

This article is focused on the problem of the inhibition of the hydrodeoxygenation (HDO) reaction by competitive adsorption of the S-containing compounds on the active sites. The phosphorous effect during co-processing of pyrolysis bio-oils and S-content model compounds over sulfide NiMo/P/HMS-Al catalysts was investigated. A series of NiMo catalysts supported on mesoporous P(x)/HMS-Al materials were prepared and characterized by several techniques. Guaiacol (GUA) was considered as a pyrolysis bio-oils model compound, while the dibenzothiophene (DBT) was used as a model molecule of S-content. The activity test revealed that support modification with 1.1 wt% of P (NM-P1.1) decreased the inhibition of HDO reaction by co-adsorption of DBT on the active sites. With the most active NM-P1.1 catalyst, the formation of a less susceptible to coke formation product (phenol) was favored. The main superiority of sulfided NM-P1.1 catalyst comes from the support decoration with P2O5 nanoparticles leading to its highest Brønsted acidity, the surface enrichment with metal sulfide species as well as with the diminishing of Al leaching from the framework of support during the HDO reaction. The activity tests demonstrated that support modification with phosphorous is an efficient method to solve the problem of the HDS inhibition by the HDO reaction.

Multicopper oxidase (MCO) laccase from Stropharia sp. ITCC-8422: an apparent authentication using integrated experimental and in silico analysis.

In the present study, specificity of laccase from Stropharia sp. ITCC-8422 against various substrates, i.e. 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,6-dimethoxyphenol (DMP), guaiacol (GCL) and syringaldazine (SYZ) was determined. It exhibited maximum affinity against ABTS, followed by DMP and negligible activity for GCL and SYZ. As the concentration of substrate increased from 0.5 to 1.5mM (ABTS) and 1 to 5mM (DMP), the activity increased from 301.1 to 567.8U/L and 254.4 to 436.2U/L. Further, quadrupole time-of-flight liquid chromatography mass spectrometry (QTOF-LCMS) analysis of the extracellular proteome of Stropharia sp. ITCC-8422 identified eighty-four (84) extracellular proteins. The peptide sequence for the enzyme of interest exhibited sequence similarity with laccase-5 of Trametes pubescens. Using high molecular mass sequence of laccase-5, the protein structure of laccase was modelled and binding energy of laccase with four substrates, i.e. ABTS (-5.65), DMP (-4.65), GCL (-4.66) and SYZ (-5.5) was determined using autodock tool. The experimental and in silico analyses revealed maximum activity of laccase and lowest binding energy with ABTS. Besides, laccase was purified and it exhibited 2.1-fold purification with purification yield of 20.4% and had stability of 70% at pH 5-9 and 30-40℃. In addition, the bioremediation potential of laccase was explored by in silico analysis, where the binding energy of laccase with alizarin cyanine green was -6.37 and both in silico work and experimental work were in agreement.

Catalytic effects of ammonium dihydrogen phosphate on the pyrolysis of lignocellulosic biomass: Selective production of furfural and levoglucosenone

The catalytic effects of ammonium dihydrogen phosphate (ADP) on the biomass pyrolysis and its mechanism for the selective production of furfural (FF) and levoglucosenone (LGO) were investigated in this study. Samples were prepared with rice husk and ADP solutions with gradient-concentration and pyrolyzed via TG-FTIR and Py-GC/MS. Results showed that ADP made the decomposition of cellulose occur at a lower temperature and greatly enhanced the release of CO groups and carbohydrates below 300 °C, indicating the breakage of glycosidic bond and dehydration reaction during pyrolysis were promoted by ADP. In the pyrolysis volatiles, the production of anhydrosugars and furans was promoted significantly. Due to the rearrangement of the methoxy group, the production of methoxy phenols and CH4 was decreased simultaneously. ADP showed good selectivity for both FF and LGO. With the increased ADP dose, the yield and relative content of FF and LGO increased firstly and then kept stable. 400 °C was found the optimal temperature for the production of FF and LGO, where the sum of the relative peak area of LGO and FF could reach 52.23%. Finally, a possible formation pathway of LGO and FF under the catalysis of ADP was speculated.

Optimization and Characterization of Wood Vinegar Produced by <i>Shorea laevis</i> Ridl Wood Pyrolysis

In this study, the Box-Behnken Design (BBD) was employed to investigate the effects of wood particle size, pyrolysis temperature, and pyrolysis time on the production of wood vinegar from Indonesia “bengkirai” wood (Shorea laevis Ridl). Characterization of wood vinegar was conducted by gas chromatography-mass spectrometry (GC-MS). Three variable designs consisting of wood particle size (2.00, 2.38, and 3.36 mm), pyrolysis temperature (350, 400, and 450 °C), and pyrolysis time (105, 120, and 135 min) were employed in a BBD response surface methodology (RSM-BBD). RSM-BBD results suggested that maximum wood vinegar yield would be obtained with a wood particle size of 3.85 mm, pyrolysis temperature of 400 °C, and pyrolysis time of 93 min. In addition, the mathematical model indicated the maximum wood vinegar yield would be 30.31%. The main compounds in wood vinegar were acetic acid, 1-hydroxy-2-propanone, furfural, 2,3-pentanedione, phenol, 2-methoxy phenol, 2-methoxy-4-methyl phenol, 2,6-dimethoxy phenol, and 1,2,4-trimethoxybenzene.

Hydrodeoxygenation of bio-oil and model compounds for production of chemical materials at atmospheric pressure over nickel-based zeolite catalysts

ABSTRACT Nickel-based zeolite (HY, HBeta, MCM-41-γ-Al2O3 and MCM-41-HBeta) catalysts were prepared by impregnating using Fe and Ga. The prepared nickel-based zeolite catalysts were characterized by N2 sorption studies, X-ray diffraction, NH3-temperature programmed desorption and scanning electron microscope. The hydrodeoxygenation (HDO) performance of the prepared catalysts were evaluated using guaiacol (GUA) as a bio-oil model compound in a fixed bed. Results showed that GaNi/MCM-41-HBeta had a high selectivity for the target products of benzene and its derivatives. Moreover, the HDO pathways of GUA were analyzed, which provided a reference for the bio-oil HDO. HDO experiments of bio-oil showed that the hydrocarbon content and yield of GaNi/MCM-41-HBeta reached a maximum value of 93.31% (light oil), 35.39% (light oil), 92.11% (heavy oil) and 46.90% (heavy oil), respectively. The contents of benzene and its derivatives in the upgraded oils were 28.16% (light oil) and 30.03% (heavy oil), respectively.

Phenols production form Douglas fir catalytic pyrolysis with MgO and biomass-derived activated carbon catalysts

Catalytic pyrolysis of Douglas fir with MgO and biomass-derived activated carbon catalysts (MAC) was investigated for the first time. The effects of MAC to Douglas fir ratio, experimental temperature, and MgO to activated carbon ratio on product distributions were studied. The bio-oil yields varied from 45.7 to 58.5 wt% under various experimental conditions. The main bio-oil products from the catalytic pyrolysis of Douglas fir were phenols, furans, aldehydes, and ketones. Methane, hydrogen, carbon dioxide, and carbon monoxide were the dominant gas products. The bio-oil yields, the selectivities of phenols and furans, and the proportion of target gas products were increased with the addition of catalysts compared to Douglas fir pyrolysis without catalysts, but the effect of MAC to Douglas fir ratio was negative for the bio-oil yield. The alkylation of methoxy phenols was promoted by MgO. According to the different experimental results, the maximum production of bio-oils was acquired at the experimental condition of 500 °C, MAC to Douglas fir ratio of 1:2, and MgO to activated carbon ratio of 0.2. This work could provide a novel and viable way for the conversion of Douglas fir into high bio-oil yield and relieve the stress of energy shortages and environmental pollution.

Ultrasonic studies on ternary liquid mixtures of some 1-alkanols with meta methoxy phenol and n hexane at 313 K

Abstract The thermo-physical parameters like density (ρ), ultrasonic velocity (U) and viscosity (η) have been experimentally measured for the Ternary Liquid Mixtures of Meta Methoxy Phenol (MMP) in n Hexane with 1 alkanols such as 1 propanol or 1 butanol or 1 pentanol at constant temperature 313 K and fixed frequency of 2 MHz. The thermodynamic and acoustical parameters such as adiabatic compressibility(β), absorption coefficient (α/f2), internal pressure(πi), cohesive energy(CE), free volume(Vf), free length(Lf), acoustic impedance(z), available volume(Va), viscous relaxation time, ∆G value, Lenard Jones potential, Degree of intermolecular interaction(χ) and K value were calculated from the experimental data. The various excess properties including excess acoustic impedance(ZE), excess free length(Lf)E, excess adiabatic compressibility(βE), excess free volume(VfE), excess ultrasonic velocity (UE) and excess internal pressure(πiE) were also computed from the calculated values. The values of UE, ZE, and LfE for each mixture have been fitted to the Redlich –Kister polynomial equation. The variation of these parameters with respect to different concentration at constant temperature for the three systems namely MMP+ 1 Propanol+n Hexane, MMP+ 1 Butanol+n Hexane and MMP+ 1 Pentanol+n Hexane have been discussed in the light of molecular interaction. Further, theoretical studies like Van Dael Ideal Mixing Relation, Impedance Dependant Relation, Junjie's and Nomoto's relation are validated with respect to experimental velocities at 313 K for all the different concentrations ranging from 0.001 M to 0.01 M of all the three systems and the Chi-square test for the goodness of fit is applied to check the validity of the theories.

Hydrodeoxygenation of 2-methoxy phenol: Effects of catalysts and process parameters on conversion and products selectivity

The hydrodeoxygenation (HDO) of 2-methoxy phenol (MP), a lignin-derived compound, has massive prospective for valuable compounds production. The lignin derived model compounds can be used for production of green chemicals. The model compound MP conversion into cyclohexane was investigated over Ru metal loaded on various supports (ZSM-5, Y-zeolite, β-zeolite, COK-12, mordenite, ZrO2, and TiO2). The catalytic properties such as the acidic sites, pore size, and morphology influenced the HDO activity and selectivity of the cyclohexane. The yield of cyclohexane increases up to optimum acidity further increases the acidity of the catalyst, the product yield decreased. The experiments carried out at temperature range of 200–300 °C, and 1–25 bar hydrogen pressure in a fixed bed reactor. The parameters greatly influenced the HDO as well as the cyclohexane yield, selectivity, and MP conversion. The highest conversion (100%) and yield of cyclohexane (99.0%) observed at 250 °C under pressure of 20 bar with Ru/ZSM-5 catalyst. Further the recyclability and stability have been checked and observed that Ru/ZSM-5 is stable up to 200 h and displayed excellence activity in both HDO and cyclohexane selectivity. Weight hourly space velocity (WHSV) was investigated (0.5–1.5 h−1). The suitable WHSV found for HDO of 2-methoxy phenol and cyclohexane yield was 1 h−1. The reaction mechanism showed that the Ru/ZSM-5 catalyst provoked the HDO compared to the others catalyst.

Probing Intramolecular Interaction of Stereoisomers Using Computational Spectroscopy

Several model stereoisomers such as ferrocene (Fc), methoxyphenol, and furfural conformers are discussed. It was discovered that the Fc IR spectroscopic band(s) below 500cm−1 serve as fingerprints for eclipsed (splitting 17 (471–488)cm−1) and staggered Fc (splitting is ~2 (459–461)cm−1) in the gas phase. It is revealed that in the gas phase the dominance of the eclipsed Fc (D5h) at very low temperatures changes to a mixture of both eclipsed and staggered Fc when the temperature increases. However, in solvents such as CCl4, eclipsed Fc dominates at room temperature (300K) due to the additional solvation energy. Intramolecular interactions of organic model compounds such as methoxyphenols (guaiacol (GUA) and mequinol (MEQ)) and furfural, ionization energies such as the carbon 1s (core C1s), as well as valence binding energy spectra serve this purpose well. Hydrogen bonding alters the C1s binding energies of the methoxy carbon (C(7)) of anti-syn and anti-gauche conformers of GUA to 292.65 and 291.91eV, respectively. The trans and cis MEQ conformers, on the other hand, are nearly energy degenerate, whereas their dipole moments are significantly different: 2.66 Debye for cis and 0.63 Debye for trans-MEQ. Moreover, it is found that rotation around the Cring–OH and the Cring–OCH3 bonds differ in energy barrier height by ~0.50 kcal⋅mol−1. The Dyson orbital momentum profiles of the most different ionic states, 25a′ (0.35eV) and 3a′ (−0.33eV), between cis and trans-MEQ in outer valence space (which is measurable using electron momentum spectroscopy (EMS)), exhibit quantitative differences. Finally, the molecular switch from trans and cis-furfural engages with a small energy difference of 0.74 kcal mol−1, however, at the calculated C(3)(–H⋅⋅⋅O=C) site the C1s binding energy difference is 0.105eV (2.42 kcal mol−1) and the NMR chemical shift of the same carbon site is also significant; 7.58ppm from cis-furfural without hydrogen bonding.

Studies On Molecular Interactions In Ternary Liquid Mixture Of Ortho Methoxy Phenol And 1 Propanol In n- Hexane At Various Temperatures Using Ultrasonic Technique

The thermo-physical parameters like density (ρ), ultrasonic velocity (U) and viscosity (η) have been experimentally measured for the Ternary Liquid Mixture of Ortho Methoxy Phenol (OMP)and 1 propanol in n hexaneat different temperatures viz. 303 K, 308 K, 313 K. The thermodynamic and acoustical parameters such as adiabatic compressibility(β), Rao (R), absorption coefficient (α/f2), internal pressure(πi), cohesive energy(CE), free volume(Vf), free length(Lf), acoustic impedance(z), available volume(Va), viscous relaxation time and Lenard Jones potential were calculated from the experimental data. The various excess properties including excess Ultrasonic velocity, excess acoustic impedance, excess free length, excess adiabatic compressibility, excess free volume and excess internal pressure were also computed. The variation of these parameters with respect to concentration and temperatures have been discussed in the light of molecular interaction

AcetylCoA Carboxylase and Antioxidant Enzymes Activity of Sunflower under Influence of Supergallant Herbicide by Magnetic Water

AbstractApproaches for reducing effects the destructive effects of herbicides and increasing water use efficiency have gathered the interest of researchers over the last few decades. This study aims to investigate the protective effects of irrigation with magnetic water (MWT) on acetyl coenzyme A carboxylase (ACCase) and antioxidant enzymes activity of sunflower (Helianthus annuus L. cv. Lakomka) against undesirable effects of super gallant herbicide. It was conducted in a completely randomized design with 4 levels of super gallant herbicide (0, 25, 50 and 75 ppm) in three replications. Small necrotic spots were observed on some MWT and normal water treated leaves due to the herbicide effect. Although proline content was increased in response to herbicide toxicity, MWT plants had significantly higher proline level than corresponding control ones. On the other hand, malone dialdehyde content as a marker of membrane damage showed dramatic increase due to herbicide treatment. Also, ascorbate peroxidase and catalase activities were raised by super gallant despite of decline in guaiacol peroxidase activity in herbicide concentration dependent manner. Herbicide reduced activity of ACCase in both roots and shoots significantly, but MWT could ameliorate this effect very well. It seems that MWT may be considered as an appropriate solution to cope the negative effects of herbicide super gallant.

Efficient hydrodeoxygenation of guaiacol and fast-pyrolysis oil from rice straw over PtNiMo/SBA-15 catalyst for co-processing in fluid catalytic cracking process

Fast pyrolysis of renewable biomass is an attractive approach to convert solid biomass into a liquid which has higher energy density. However, pyrolysis oil has high acidity, low energy value, high viscocity and instability that limit end-user applications. This study focuses on the upgrading of pyrolysis oil using hydrodeoxygenation (HDO) process to produce a suitable bio-oil that can be further co-processed in standard refinery. In the first part, Pt was added to NiMo/SBA-15 catalyst in order to improve the HDO activity of guaiacol (GUA) and of fast pyrolysis oil from rice straw. Pt addition leads to important increases in both GUA conversion and HDO degree, and more interestingly, to the domination of saturated cyclic compounds (80–95 %) among formed products. Temperature programed reduction analysis proved that the reduction of Ni and Mo species occurred at lower temperatures with the presence of Pt. The use of 0.7 PtNiMo/SBA-15 catalyst resulted in the very high GUA conversion (94.5 %), high HDO degree (98.7 %), and high saturated cyclic compounds selectivity (97.4 %). In addition, the HDO treatment of fast pyrolysis oil over this catalyst at 300 °C, 12 MPa leads to a decrease in oxygen content from 44 wt.% to 20 wt.%. Then, the second part of this work has shown that HDO bio-oil obtained can be co-processed (up to 20 wt.% of bio-oil) with vacuum gasoil (VGO) in fluid catalytic cracking lab-scale unit (short contact time micro-activity unit, SCT-MAT) without significant change of the yield of profitable products: liquid petroleum gas, gasoline and light cycle oil.

Jet-cooled rovibrational spectroscopy of methoxyphenols using two complementary FTIR and QCL based spectrometers.

Methoxyphenols (MPs) are a significant component of biomass burning emissions which mainly exists in our atmosphere in the gas phase where they contribute to the formation of secondary organic aerosols (SOAs). Rovibrational spectroscopy is a promising tool to monitor atmospheric MPs and infer their role in SOA formation. In this study, we bring a new perspective on the rovibrational analysis of MP isomers by taking advantage of two complementary devices combining jet-cooled environments and absorption spectroscopy: the Jet-AILES and the SPIRALES setups. Based on Q-branch frequency positions measured in the Jet-AILES Fourier-transform infrared (FTIR) spectra and guided by quantum chemistry calculations, we propose an extended vibrational and conformational analysis of the different MP isomers in their fingerprint region. Some modes such as far-IR out-of-plane -OH bending or mid-IR in-plane -CH bending allow us to assign individually all the stable conformers. Finally, using the SPIRALES setup with three different external cavity quantum cascade laser sources centered on the 930-990 cm-1 and the 1580-1690 cm-1 ranges, it was possible to proceed to the rovibrational analysis of the ν18 ring in-plane bending mode of the MP meta isomer providing a set of reliable excited state parameters, which confirms the correct assignment of two conformers. Interestingly, the observation of broad Q-branches without visible P- and R-branches in the region of the C-C ring stretching bands was interpreted as being probably due to a vibrational perturbation. These results highlight the complementarity of broadband FTIR and narrowband laser spectroscopic techniques to reveal the vibrational conformational signatures of atmospheric compounds over a large infrared spectral range.

Stability Indicating RP-HPLC Method for Simultaneous Determination of Pholcodine and Guaiacol in Pharmaceutical Syrup

Guaiacol (GUA) and pholcodine (PHO) were simultaneously determined in a pharmaceutical syrup using RP-HPLC with UV detection. The separation was performed using X-Bridge C8 column (100 mm × 4.6 mm, 2.5 μm particle size) and a mobile phase of acetonitrile – phosphate buffer (pH 6.8; 50 mM) (25:75, v/v) at a flow rate of 0.55 mL/min. The column temperature was adjusted to 35°C, and the detector was set to measure the absorbance at 238 nm. The ICH guidelines were followed to validate the method. The linearity was studied over 6.0 – 70 μg/mL and 4 – 420 μg/mL ranges for GUA and PHO, respectively. Linear relationships were obtained over the specified concentration ranges with correlation coefficients of 0.9989 for GUA and 0.9999 for PHO. The limits of detection were also determined and found to be 2 μg/mL for GUA and 1.2 μg/mL for PHO. The proposed method was applied for the determination of both drugs in Coughpent syrup; the results comply with the label claim (0.1572g/120mL for PHO and 0.0237g/120mL for GUA).