Benzyl Alcohol Concentration Research Articles

Transcending Lifshitz Theory: Reliable Prediction of Adhesion Forces between Hydrocarbon Surfaces in Condensed Phases Using Molecular Contact Thermodynamics.

Lifshitz theory is widely used to calculate interfacial interaction energies and underpins established approaches to the interpretation of measurement data from experimental methods including the surface forces apparatus and the atomic force microscope. However, a significant limitation of Lifshitz theory is that it uses the bulk dielectric properties of the medium to predict the work of adhesion. Here, we demonstrate that a different approach, in which the interactions between molecules at surfaces and in the medium are described by a set of surface site interaction points (SSIPs), yields interaction free energies that are correlated better with experimentally determined values. The work of adhesion W(Lifshitz) between hydrocarbon surfaces was calculated in 260 liquids using Lifshitz theory and compared with interaction free energies ΔΔG calculated using the SSIP model. The predictions of these models diverge in significant ways. In particular, ΔΔG values for hydrocarbon surfaces are typically small and vary little, but in contrast, W(Lifshitz) values span 4 orders of magnitude. Moreover, the SSIP model yields significantly different ΔΔG values in some liquids for which Lifshitz theory predicts similar values of W(Lifshitz). These divergent predictions were tested using atomic force microscopy. Experimentally determined works of adhesion were closer to the values predicted using the SSIP model than Lifshitz theory. In mixtures of methanol and benzyl alcohol, even greater differences were found in the interaction energies calculated using the two models: the value of ΔΔG calculated using the SSIP model declines smoothly as the benzyl alcohol concentration increases, and values are well correlated with experimental data; however, W(Lifshitz) decreases to a minimum and then increases, reaching a larger value for benzyl alcohol than for methanol. We conclude that the SSIP model provides more reliable estimates of the work of adhesion than Lifshitz theory.

Exploring changes in key aroma-active compounds of soy sauce due to different fermentation processes

In this study, two extraction methods combined with gas chromatography-olfactometry-mass spectrometry (GC×GC-O-MS) were used to investigate the sensory characteristics of high-salt dilute fermented soy sauce (HDFSS), and molecular sensory methods were used to characterize its aroma. Among them, 3-methylthiopropanal had the highest odor activity value (OAV) in HDFSS, and acetic acid had the highest content in HDFSS. The results showed that the concentrations of benzyl alcohol, phenethyl alcohol, 1-octen-3-ol, maltol, and 1-hydroxy-2-propanone did not vary significantly in the HDFSS of different fermentation processes. The Y2 HDFSS produced in the koji-making fermentation system 2 had higher concentrations of 3-methyl-1-butanol (malt) and 3-methylthiopropanal (roasted potato). Additionally, it received high aroma scores in the sensory evaluation. Finally, by conducting aroma reconstitution and omission experiments on HDFSS from two different fermentation processes, the key aroma-active compounds, such as phenethyl alcohol, maltol, and guaiacol, were identified.

Deconvoluting the Individual Effects of Nanoparticle Proximity and Size in Thermocatalysis.

Nanoparticle (NP) size and proximity are two physical descriptors applicable to practically all NP-supported catalysts. However, with conventional catalyst design, independent variation of these descriptors to investigate their individual effects on thermocatalysis remains challenging. Using a raspberry-colloid-templating approach, we synthesized a well-defined catalyst series comprising Pd12Au88 alloy NPs of three distinct sizes and at two different interparticle distances. We show that NP size and interparticle distance independently control activity and selectivity, respectively, in the hydrogenation of benzaldehyde to benzyl alcohol and toluene. Surface-sensitive spectroscopic analysis indicates that the surfaces of smaller NPs expose a greater fraction of reactive Pd dimers, compared to inactive Pd single atoms, thereby increasing intrinsic catalytic activity. Computational simulations reveal how a larger interparticle distance improves catalytic selectivity by diminishing the local benzyl alcohol concentration profile between NPs, thus suppressing its readsorption and consequently, undesired formation of toluene. Accordingly, benzyl alcohol yield is maximized using catalysts with smaller NPs separated by larger interparticle distances, overcoming activity-selectivity trade-offs. This work exemplifies the high suitability of the modular raspberry-colloid-templating method as a model catalyst platform to isolate individual descriptors and establish clear structure-property relationships, thereby bridging the materials gap between surface science and technical catalysts.

Pd(II)‐Catalyzed Aerobic Alcohol Oxidation for Multicomponent Synthesis of 2,3‐Dihydroquinazolin‐4(1H)‐ones in Water

AbstractWe describe a multicomponent reaction between isatoic anhydrides, alkylamines and benzylic alcohols using Pd(II)/TPPMS catalyst with cocatalytic Cu(II) salt in water. This cascade reaction involves the catalytic dehydrogenation of benzyl alcohol to benzaldehyde under aerobic conditions, followed by cyclocondensation with in situ generated 2‐aminobenzamides, allowing rapid access to 2,3‐dihydroquinazolin‐4(1H)‐ones (DHQs). This practical method enables direct access to a series of DHQs without strong bases and hazardous oxidants. Mechanistic studies reveal that the multicomponent reaction is first order with respect to the concentrations of benzyl alcohol and catalysts, and proceeds independently of the concentration of the 2‐aminobenzamide intermediate.

Urinary benzyl alcohol and hippuric acid in workers exposed to benzyl alcohol during paint-stripping work.

We aimed to develop a reliable gas chromatography-mass spectrometry (GC-MS) method for detecting urinary benzyl alcohol (BeOH) concentrations and assess the suitability of urinary BeOH as a biomarker for occupational BeOH exposure. Thirteen male participants exposed to BeOH during paint-stripping work provided preshift and postshift urine samples, and their personal exposure concentrations were measured. Meanwhile, a control group of 10 nonexposed workers contributed urine samples. The newly developed GC-MS method met regulatory guidelines. The personal exposure concentrations of BeOH ranged from 8.4 to 45.2mg/m3. Postshift urine samples from exposed participants showed significant BeOH and hippuric acid (HA) concentration increases compared with preshift samples (BeOH, post-/pre-shift geometric mean [GM] ratio = 7.5-7.8, P < .001; HA, post-/pre-shift GM ratio = 4.3-4.5, P < .001). These levels were considerably higher than those in postshift samples from the nonexposed control group (BeOH, exposed-/nonexposed-workers GM ratio = 14.8-19.0, P < .001; HA, exposed-/nonexposed-workers GM ratio = 12.1-15.3, P < .001), even after urine density correction. Urinary BeOH and HA can serve as potential biomarkers of occupational exposure to BeOH. More specifically, BeOH might serve as a biomarker superior to HA because it is apparently less influenced by confounding factors such as dietary intake and genetic polymorphism of low-Km aldehyde dehydrogenase (ALDH2). The findings will improve workplace safety measures and protocols, assisting health care professionals in diagnosing and managing exposure-related health issues, thereby potentially reducing the risk of occupational exposure to BeOH.

An investigation of the acaricidal activity of benzyl alcohol on Rhipicephalus annulatus and Rhipicephalus sanguineus and its synergistic or antagonistic interaction with commonly used acaricides.

The most economically significant ectoparasites in the tropics and subtropics are ixodid ticks, especially Rhipicephalus annulatus and Rhipicephalus sanguineus. Years of extensive use of the readily available acaricides have resulted in widespread resistance development in these ticks, as well as negative environmental consequences. Benzyl alcohol (BA) has been frequently used to treat pediculosis and scabies, and it may be an effective alternative to commonly used acaricides. The main aim of the present study was to evaluate the acaricide activity of BA and its combination with the regularly used chemical acaricides against R. annulatus and R. sanguineus. Different concentrations of BA alone and in combination with deltamethrin, cypermethrin and chlorpyrifos were tested in vitro against adult and larvae of both tick species. The results showed that BA is toxic to R. annulatus and R. sanguineus larvae, with 100% larval mortality at concentrations of ≥50 mL/L, and LC50 and LC90 attained the concentrations of 19.8 and 33.8 mL/L for R. annulatus and 18.8 and 31.8 mL/L for R. sanguineus, respectively. Furthermore, BA in combination with deltamethrin, cypermethrin and chlorpyrifos exhibited synergistic factors of 2.48, 1.26 and 1.68 against R. annulatus larvae and 1.64, 11.1 and 1.14 against R. sanguineus larvae for deltamethrin + BA, cypermethrin + BA and chlorpyrifos + BA, respectively. BA induced 100% mortality in adult R. annulatus at concentrations of ≥250 mL/L with LC50 and LC90 reached the concentrations of 111 and 154 mL/L, respectively. Additionally, BA had ovicidal activity causing complete inhibition of larval hatching at 100 mL/L. The combination of BA with deltamethrin and cypermethrin increased acetylcholinesterase inhibition, whereas the combination of BA with chlorpyrifos decreased glutathione (GSH) activity and malondialdehyde levels. In the field application, the combination of BA 50 mL/L and deltamethrin (DBA) resulted in a significant reduction in the percentage of ticks by 30.9% 28 days post-treatment when compared with groups treated with deltamethrin alone. In conclusion, BA causes mortality in laboratory and field studies alone and in combination with cypermethrin or deltamethrin. BA can be used for control of ticks of different life stages, that is, eggs and larvae, through application to the ground.

Research on the Bending Impact Resistance and Transverse Fracture Characteristics of Bamboo under the Action of Falling Weight

Drop weight impact tester was used to accurately measure the bending impact resistance of various parts of Phyllostachys edulis, commonly known as moso bamboo, with a growth cycle of 3–8 years. Cellulose crystallinity in the bottom (B), middle (M) and top (T) of bamboo at different ages was calculated using peak height analysis in X-ray diffraction. Heatmap of Spearman correlation analysis was used to represent the correlation between chemical composition and impact mechanics. The breaking load (BL), fracture energy (FE) and impact deflection (ID) of 3–8-yearold bamboo were found to be in the range of ~670–2120 N, ~5.17–15.55 J, and ~3.60–~17.76 mm, respectively. As the growth period of bamboo rises, the cellulose crystallinity at the B and T decreases first and then increases, while that for the M increases first and then remains stable. Similarly, the bending impact performance of bamboo was found to become stable with its growth and age. The flexural impact and toughness of the 4-year-old bamboo base material were better than other specimens. The enhancement in the bending impact properties of bamboo at different growth periods was influenced by the lignin content, while the value of FE was mainly positively correlated with ash, cold and hot water extracts and benzyl alcohol content. However the content of holocellulose and pentosan, air-dry density and, base density negatively influenced the FE. With the change in the height of the bamboo, the correlation between its impact mechanical properties and chemical composition gradually decreased. This study provides data support and theoretical basis for the age-appropriate thinning and application of moso bamboo.

Thermodynamic properties of binary liquid mixtures of benzyl alcohol with 2-Alkoxyethanols at varying temperatures

In the present research, density (ρ) and speed of sound (u) for binary liquid mixtures of the benzyl alcohol (BA) with three 2-alkoxyalcohols {2-methoxyethanol (2-ME), 2-ethoxyethanol (2-EE), and 2-butoxyethanol (2-BE)} at temperatures of 298.15, 303,15 and 308.15 K have been measured over complete concentration of benzyl alcohol under 0.1 MPa pressure. According to measured results, excess molar volume (VmE) and deviation in isentropic compressibility (Δκs) were computed and these observed results were correlated to Redlich−Kister (R-K) polynomial expansion. Further, molar volume (Vm), apparent molar volumes (Vm,∅,1 and Vm,∅,2), acoustic impedance (Z), isentropic compressibility (ks), intermolecular free length (Lf), deviation in intermolecular free length (ΔLf) were calculated at all worked temperatures. For all studied systems, excess molar volume (VmE) and deviation in isentropic compressibility (Δκs), and deviation in intermolecular free length (ΔLf) were negative over the entire mole fraction range of benzyl alcohol at all measured temperatures. Among the three systems, benzyl alcohol with 2-ethoxyethanol containing system showed more negative. By using the obtained results, intermolecular interactions were discussed between benzyl alcohol and 2-alkoxyethanols. Moreover, the influence of temperature on intermolecular interactions was analyzed using above said parameters.

Effect of Benzyl Alcohol on Biomethanation from Lignite.

Currently, biomethane obtained from coal resources, such as lignite and peat, serves as a sustainable biofuel urgently needed by the energy economy. To improve biomethane yield from lignite, the effects of different concentrations of benzyl alcohol, a degraded product of humic acid, on a biomethanation fermentation system were analyzed. The total biomethane yield, daily biomethane yield, coenzyme F420, VFA (volatile fatty acids) concentration, alkalinity, and pH were used to determine the optimal benzyl alcohol concentration. The biomethanation fermentation system with 2000 mg/L benzyl alcohol produced up to 4.03 mL/g of biomethane, which was 1.15 times that produced from the control group. The coenzyme F420, VFA, alkalinity, and pH of the system after adding 2000 mg/L benzyl alcohol were more preferable after adding other concentrations during the lignite biomethanation process. In summary, 2000 mg/L benzyl alcohol had a significantly positive effect on the lignite biomethanation fermentation system. When benzyl alcohol is added to the fermentation system, it accelerates the tricarboxylic acid cycle, which in turn produces more biomethane. Additionally, the self-supply of lignite microbial transformation nutrients from the perspective of chemical composition was explored as a novel approach in solving the common problem of low biomethane yield from a single lignite raw material. This also laid a foundation for subsequent steps through the adjustment of pretreatment conditions to ensure that the lignite pretreatment liquid contained increased benzyl alcohol, and a greater yield of biomethane can be produced after activated sludge addition.

Transitioning from a lab-scale PLGA microparticle formulation to pilot-scale manufacturing.

The complexity of scale-up manufacturing of PLGA microparticles creates a significant challenge when transitioning from benchtop-scale formulation development into larger clinical scale batches. Minor changes in the initial formulation composition (e.g., PLGA molecular weight, solvent type, and drug concentration) and processing parameters (e.g., extraction kinetics and drying condition) during scale-up production can result in significantly different performance of the prepared microparticles. The objectives of the present study were to highlight the in vitro and in vivo performance of a candidate benchtop-scale batch created with a rotor-stator mixer, transitioned into an in-line manufacturing process at ~15× scale of a long-acting naltrexone formulation. Physicochemical properties (such as drug loading, residual benzyl alcohol content, and morphology) as well as the in vitro release characteristics of the prepared naltrexone microparticles between the benchtop-scale and in-line process pilot-scale were determined. The pharmacokinetics of the naltrexone microspheres were investigated using the rat model. The results demonstrate that while the morphologies of the particles were different from a visual assessment and slight differences were observed in the in vitro release profiles, the in vivo pharmacokinetics illustrate similar kinetics. Our study shows that scale-up production having the same drug release kinetics can be made by controlling the formulation and processing parameters.

Different Temperature and UV Patterns Modulate Berry Maturation and Volatile Compounds Accumulation in Vitis sp.

Volatile compounds (VCs) in grapevine berries play an important role in wine quality; however, such compounds and vine development can be sensitive to environmental conditions. Due to this sensitivity, changes in temperature patterns due to global warming are likely to further impact grape production and berry composition. The aim of this study was to determine the possible effects of different growing-degree day accumulation patterns on berry ripening and composition at harvest. An experimental field was conducted using Vitis sp. L'Acadie blanc, in Nova Scotia, Canada. Using on-the-row mini-greenhouses, moderate temperature increase and reduced ultraviolet (UV) exposure were triggered in grapevines during pre-veraison (inflorescence to the beginning of berry softening), post-veraison (berry softening to full maturity), and whole season (inflorescence to full maturity), while controls were left without treatment. Free and bound VCs were extracted from berries sampled at three different phenological stages between veraison and maturity before analysis by gas chromatography–mass spectrometry (GC-MS). Berries from grapevines exposed to higher temperatures during early berry development (pre-veraison and whole) accumulated significantly higher concentrations of benzene derivatives 2-phenylethanol and benzyl alcohol at harvest, but lower concentrations of hydroxy-methoxy-substituted volatile phenols, terpenes, and C13-norisoprenoids than the control berries. These results illustrate the importance of different environmental interactions in berry composition and suggest that temperature could potentially modulate phenylpropanoid and mevalonate metabolism in developing berries. This study provides insights into the relationships between abiotic conditions and secondary metabolism in grapevine and highlights the significance of early developmental stages on berry quality at harvest.

Process Development for Benzyl Alcohol Production by Whole-Cell Biocatalysis in Stirred and Packed Bed Reactors.

The ocean is an excellent source for new biocatalysts due to the tremendous genetic diversity of marine microorganisms, and it may contribute to the development of sustainable industrial processes. A marine bacterium was isolated and selected for the conversion of benzaldehyde to benzyl alcohol, which is an important chemical employed as a precursor for producing esters for cosmetics and other industries. Enzymatic production routes are of interest for sustainable processes. To overcome benzaldehyde low water solubility, DMSO was used as a biocompatible cosolvent up to a concentration of 10% (v/v). A two-phase system with n-hexane, n-heptane, or n-hexadecane as organic phase allowed at least a 44% higher relative conversion of benzaldehyde than the aqueous system, and allowed higher initial substrate concentrations. Cell performance decreased with increasing product concentration but immobilization of cells in alginate improved four-fold the robustness of the biocatalyst: free and immobilized cells were inhibited at concentrations of benzyl alcohol of 5 and 20 mM, respectively. Scaling up to a 100 mL stirred reactor, using a fed-batch approach, enabled a 1.5-fold increase in benzyl alcohol productivity when compared with batch mode. However, product accumulation in the reactor hindered the conversion. The use of a continuous flow reactor packed with immobilized cells enabled a 9.5-fold increase in productivity when compared with the fed-batch stirred reactor system.

Influence of Must Clarification Technique on the Volatile Composition of Albariño and Treixadura Wines.

Clarification of the musts is carried out to remove particles that cause turbidity, oxidizable polyphenols, and eliminate excess of proteins. However, an excessive clarification of the musts can lead to the reduction of volatile compound concentrations and, as a consequence, modify the sensorial properties of the wines. Therefore, in this study, the influence of two pre-fermentation clarification techniques (static settling and flotation) on the concentrations of volatile compounds has been assessed in Albariño and Treixadura wines. Fermentations were performed at an industrial scale. Volatile compounds have been identified and quantified by gas chromatography (FID and mass spectrometry detection) and expert panelists assessed the sensory properties of the final wines. The results showed effects of the clarification techniques on the volatile composition of wines from both varieties. Flotation significantly increased the concentrations of benzyl alcohol in Treixadura wines, whereas this technique increased the concentration of 1-hexanol, octanoic acid, and furfural in Albariño wines, but without exceeding the corresponding perception thresholds. Panelists tended to score higher the wines coming from flotation, which, together with the shorter application time, makes this technique suitable for clarifying the musts of these two white varieties.

Mechanism and kinetics of the aerobic oxidation of benzyl alcohol to benzaldehyde catalyzed by cobalt porphyrin in a membrane microchannel reactor

The highly efficient selective aerobic oxidation of benzyl alcohol to benzaldehyde catalyzed by cobalt porphyrin was achieved in a membrane microchannel reactor. The efficiency of benzyl alcohol oxidation was remarkably improved in the micro-structured chemical system, achieving a conversion and benzaldehyde selectivity of 82% and 98%, respectively, in 6.5 min. The classification and transfer of free radicals, as well as the oxygen-transfer mechanism, were determined by in situ EPR (electron paramagnetic resonance) and in situ UV–visible spectroscopy. Further kinetic studies revealed that the oxidation of benzyl alcohol follows the Michaelis–Menten kinetics, with Km = 0.133 mol/L.A mathematic kinetic model was proposed, and the kinetic model fitted the experimental data well. The mathematical model can predict the reaction process at a wide range of benzyl alcohol concentrations, which is beneficial for the process optimization and reactor design.

Development and Validation of an analytical method for the determination of Ofloxacin and Benzyl alcohol in a Pharmaceutical mixture

The aim of the study is to develop a validated, rapid, simple and low-cost method for estimating ofloxacin and benzyl alcohol in a combined dosage. Materials and methods: Materials which were used ofloxacin pure substance and benzyl alcohol pure substance which were determined by UV spectrophotometer using ethanol 95% as a solvent and a blank. Results and discussion: Ofloxacin shows the absorption maxima at 300.0 ± 2.0 nm in ethanol 95% with an apparent concentration absorptivity of (30 to 90) µg/ml and benzyl alcohol shows the absorption maxima at 312.0 ± 2.0 nm in ethanol 95% with an apparent concentration absorptivity of (60 to 200) µg/ml, it was found that in the selected range of application of the method there is a directly proportional relationship between the concentration of ofloxacin and benzyl alcohol respectively, in the measured samples and the analytical signal, linear dependence is characterized by high correlation coefficients (R&gt; 0.999)for both of drugs, which is considered acceptable for establishing strict linearity. Conclusion: The method has been verified as it has been proven simple, fast, accurate and low-cost method and does not require any expensive equipment for the analysis of Ofloxacin and benzyl alcohol separately and in a pharmaceutical mixture.

Quality of oxytocin and misoprostol in health facilities of Rwanda.

Sustainable Development Goal 3.1 calls for a reduction of the maternal mortality ratio to less than 70 per 100,000 live births by 2030. The most important cause of maternal mortality is post-partum haemorrhage (PPH). Oxytocin injections and misoprostol tablets are medicines of first choice for the management of PPH in low- and middle-income countries (LMICs). Unfortunately, both substances are chemically unstable, and previous studies have revealed serious quality problems of these medicines in LMICs. The present study is the first report on their quality in Rwanda. From 40 randomly selected health facilities (hospitals, health centers, retail pharmacies and private clinics) in different parts of Rwanda, as well as from six wholesalers and government stores, oxytocin injections and misoprostol tablets were collected. Oxytocin storage temperatures in the health facilities were monitored for six months using temperature data loggers, and found to correctly follow the storage requirements stated by the manufacturers (2–8°C, or room temperature) with few minor deviations. Oxytocin injections (57 samples, representing seven batches of four brands) were tested for their oxytocin content and pH value according to the United States Pharmacopeia. Twenty-four samples from three European manufacturers passed all tests. However, all nine samples of one batch of a Chinese manufacturer showed an excessive content of oxytocin (range 117.2–121.5% of the declared amount). Another batch of the same manufacturer showed extreme variations of the concentration of the preservative benzyl alcohol. Misoprostol tablets (25 samples, representing ten batches of six brands) were tested for content and dissolution according to the International Pharmacopoeia. Fifteen samples passed, but all 10 samples of two brands from India failed with extreme deviations, containing only 42.5–48.7% of the stated amount of misoprostol. In conclusion, oxytocin quality in Rwanda was better than reported from other African countries. However, two extremely substandard brands of misoprostol tablets were found. The Rwandan authorities reacted quickly and efficiently, and recalled these substandard medicines from the market. For oxytocin and misoprostol, with their well-known problems of quality and stability, procurement should possibly be restricted to medicines which are WHO-prequalified or which have been manufactured in countries with stringent regulatory authorities.

Grape and Wine Composition in Vitis vinifera L. cv. Cannonau Explored by GC-MS and Sensory Analysis.

GC-FID/MS is a powerful technique used to analyze food and beverage aromas. Volatile organic compounds (VOCs) in grape berries play an important role in determining wine quality and are affected by many factors, such as climate and soil that mainly influence their relative concentrations. Wine aroma is generated by a complex mixture of compounds, and the sensory relevance of individual VOCs is far from elucidated. Herein, the VOC content (free and glycosylated) of Cannonau grape skin and juice and of Cannonau wine collected in different areas of Sardinia is explored. Wine sensory analysis was also carried out and the relationship between sensory attributes and VOCs was investigated. Although Cannonau grapes showed the same VOC fingerprint, great variability was identified between samples, although only the differences in 2-phenylethanol and benzyl alcohol concentration in the grape skins and benzyl alcohol and a terpenoid in grape juice were significantly different according to ANOVA. The correlation between VOC content and the sensory profile highlights the role played by 2-methyl-1-butanol and 2-phenylethanol in increasing wine sensory complexity.

Homogeneous catalytic oxidation of toluene under the ultrasonic action

The regularities of toluene catalytic oxidation with molecular oxygen catalyzed by cobalt (II) acetate in a liquid phase under the ultrasonic action have been researched. It was found a close relationship between the temperature and pressure of the oxidation process. The relationship determines the reaction rate, the reaction products composition, and the toluene limiting conversion value. It was found that the ratio between a sonochemical reaction rate and a toluene oxidation reaction rate without ultrasonic action increases with increasing the reaction temperature both at the process initial stage and higher values of hydrocarbon conversion. Simultaneously, an increase in the rate of toluene oxidation reaction under the ultrasonic action was detected only at a temperature of 430–438 K and a pressure of 0.4 MPa. Under all other conditions the rate of sonochemical reaction is lower than the toluene oxidation rate without ultrasonic action. An extreme reaction rate dependence of the homogeneous catalytic toluene oxidation on pressure at constant temperature was revealed. It is established that the reaction rate decreases with pressure increasing under the ultrasonic action more significantly the higher the reaction temperature is. In general the sonochemical reaction rate is lower than the rate of catalytic toluene oxidation. It was shown that ultrasound affects the concentrations of all reaction products. The relationship between the product concentrations obtained in the sonochemical reaction and in the toluene oxidation reaction without ultrasonic treatment depends on temperature and pressure. It is established that the main changes in the quantitative composition of oxidation products are to increase/decrease the benzoic acid and benzyl alcohol concentrations under the ultrasonic action. The decrease in the sonochemistry reaction rate of toluene catalytic oxidation at the reaction initial stage and its simultaneous increase at higher values of hydrocarbon conversion, as well as changes in the reaction products selectivities, and the ultrasonic effect on the toluene limiting conversion indicate that the cavitation affects on the changes in the regularities of catalyst-intermediate complexes transformations.

Stability of Fluid Ultrathin Polymer Films in Contact with Solvent-Loaded Gels for Cultural Heritage.

The removal of ultrathin amorphous polymer films in contact with an aqueous gelled solution containing small amounts of good solvent is addressed by means of specular and off-specular neutron reflectometry. The distribution of heavy water and benzyl alcohol is revealed inside Laropal A81, often employed as a protective varnish layer for Culture Heritage in the restoration of easel paintings. The swelling kinetics, interface roughness, and film morphologies were recorded as a function of temperature and increasing benzyl alcohol concentration in the dispersion of Pemulen TR-2, a hydrophobically modified acrylic acid copolymer. The addition of small amounts of good solvent results in the appearance of water-filled cavities inside the varnish, which grow with time. It is shown that while increasing the solvent concentration greatly enhances the hole growth kinetics, an increase in temperature above the glass transition temperature does not have such a big effect on the kinetics.

ESTERIFICATION OF ACETIC ACID AND BENZYL ALCOHOL OVER ZEOLITE HX PRODUCED FROM BANGKA BELITUNG KAOLIN

The activity of zeolite HX acid catalyst synthesized from kaolin was investigated for esterification of acetic acid with benzyl alcohol. Zeolite HX was synthesized using kaolin minerals obtained from Bangka Belitung Sumatra, Indonesia via hydrothermal method and followed by cation exchange treatment. The conversion of acetic acid was driven by the presence of Bronsted acidity with the porosity plays a crucial role in determining product selectivity. The influence of reactants concentration, the effect of reaction time and the amount of catalyst loading were investigated to obtain optimum condition of the reaction. Zeolite HX catalyzed esterification of acetic acid to achieve 58.78% of conversion with increasing the concentrations of benzyl alcohol enhanced the conversion. The acetic acid esterification follows the Eley-Rideal mechanism with the conversion improved by prolonging the reaction time and increasing the amount of catalyst used in the system.