Presence Of Xylene Research Articles

SYNTHESIS AND EVALUATION OF SULPHONYL BORATE ESTER AS GREASE ADDITIVE

This study includes synthesis and evaluation of an additive to improve the two main properties of lubricating grease which are; “increasing the dropping point and improving the extreme pressure (EP) properties” of Lithium grease without any negative effect on the other characteristics of lubricating grease. Increasing the dropping point and extreme pressure (EP) properties are the most important factors to widen the application of lubricating grease. The additive is synthesized via two-steps condensation reactions of polyethylene glycol 400 and Boric acid followed by reacting the product with Dodecyl-benzene sulfonic acid in the presence of Xylene as azeotropic solvent. The structure of the synthesized Sulphonyl-Borate ester SPB is confirmed by using FT-IR. Evaluation of the synthesized additive is conducted by blending it with laboratory prepared Lithium grease sample in different ratios. Analysis were carried out to study the effect of additive on the lubricating grease properties, especialy grease consistency ASTM D217, dropping point ASTM D2265, oil separation ASTM D6184, and Four–Ball test ASTM D2783. The results showed that synthesized additive increased the dropping point by 65 % and extreme pressure properties by 66 % of the prepared grease grease sample.

L-Poly(lactic acid) Production by Microwave Irradiation of Lactic Acid Obtained from Lignocellulosic Wastes.

L-polylactic acid (PLA), a semi-crystalline aliphatic polyester, is one of the most manufactured biodegradable plastics worldwide. The objective of the study was to obtain L-polylactic acid (PLA) from lignocellulosic plum biomass. Initially, the biomass was processed via pressurized hot water pretreatment at a temperature of 180 °C for 30 min at 10 MPa for carbohydrate separation. Cellulase and the beta-glucosidase enzymes were then added, and the mixture was fermented with Lacticaseibacillus rhamnosus ATCC 7469. The resulting lactic acid was concentrated and purified after ammonium sulphate and n-butanol extraction. The productivity of L-lactic acid was 2.04 ± 0.18 g/L/h. Then, the PLA was synthesized in two stages. Firstly, lactic acid was subjected to azeotropic dehydration at 140 °C for 24 h in the presence of xylene, using SnCl2 (0.4 wt.%) as a catalyst, resulting in lactide (CPLA). Secondly, microwave-assisted polymerization was carried out at 140 °C for 30 min with 0.4 wt.% SnCl2. The resulting powder was purified with methanol to produce PLA with 92.1% yield. The obtained PLA was confirmed using electrospray ionization mass spectrometry, nuclear magnetic resonance, thermogravimetric analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and X-ray diffraction. Overall, the resulting PLA can successfully replace the traditional synthetic polymers used in the packaging industry.

Syntheses of novel disperse dyes based on arylazophenols: Synthesis, characterizations and applications

ABSTRACT. Three compounds, phenyl propenone, p-tolyl propenone, and bromo phenylpropenone derivatives 3a-c were produced in good yields via condensation derivatives of acetophenone with dimethyl formamide dimethyl acetal (DMFDMA) in presence of xylene as a solvent. Compounds 5a-f were produced by coupling the enaminones 3a-c with diazonium chloride 4a or 4b. Compounds 5a-f were reacted with acetone to create novel disperse dyes 9a-f. Mass spectra, (FT-IR), elemental analysis, and 1H-NMR spectra were used to confirm the chemical structure of the new dyes. The new disperse dyes were used in dyeing polyester fabrics at low temperature, and fabrics with colors ranging from yellowish brown to dark yellowish brown were obtained. Thus, the different fastness properties of these dyed fabrics were studied, which gave excellent results. Finally, the biological activity of these new dyes was studied, which showed that they have biological activity against bacteria and fungi.
 
 KEY WORDS: Azo dye, Carrier, Low temperature dyeing, Arylazophenols, Color fastness
 Bull. Chem. Soc. Ethiop. 2023, 37(4), 993-1002. 
 DOI: https://dx.doi.org/10.4314/bcse.v37i4.15

Biological mitigation of methane in presence of xylene and ethylbenzene in biofilters: Effect of pollutants concentrations and empty bed residence time

Landfill gas emissions cause serious environmental concerns due to the presence of methane (CH4), an important greenhouse gas (GHG) and several harmful volatile organic compounds (VOCs) such as xylene (X) and ethylbenzene (EB). A series of 9 up-flow biofilters (3 sections of 0.3 m each) packed with inorganic materials were used to eliminate CH4 as a single pollutant, a binary mixture of X and EB and a ternary mixture of CH4, X and EB. The CH4 concentration range was 2000–10000 ppmv while the VOCs (X and EB) individual concentrations were 200, 400 and 600 ppmv for empty bed residence times (EBRTs) ranging from 2.25 to 9 min over a period of 242 days. The highest CH4 removal efficiency (RE) in the ternary mixture was 41 ± 3% at a CH4 concentration of 2000 ppmv and X and EB individual concentrations of 200 ppmv for an EBRT of 9 min. Meanwhile, the highest X and EB-REs of 58 ± 3 and 57 ± 3% were obtained respectively, at the same concentrations of the components but at a shorter EBRT of 4.5 min. Almost 40% of CH4 biodegradation took place on the top section of the bioreactor while 50–60% of the VOCs biodegradation occurred in the middle section.

Shotgun Metagenomic Analyses of Microbial Assemblages in the Aquatic Ecosystem of Winam Gulf of Lake Victoria, Kenya Reveals Multiclass Pollution.

Lake Victoria, the second-largest freshwater lake in the world, provides an important source of food and income, particularly fish for both domestic consumption and for export market. In recent years, Lake Victoria has suffered massive pollution from both industrial and wastewater discharge. Microplastic biomes, pharmaceutical residues, drugs of abuse, heavy metals, agrochemicals, and personal care products are ubiquitous in the aquatic ecosystem of Winam Gulf. These pollutants are known to alter microbial assemblages in aquatic ecosystems with far-reaching ramification including a calamitous consequence to human health. Indeed, some of these pollutants have been associated with human cancers and antimicrobial resistance. There is a paucity of data on the microbial profiles of this important but heavily polluted aquatic ecosystem. The current study sought to investigate the metagenomic profiles of microbial assemblages in the Winam Gulf ecosystem. Water and sediment samples were collected from several locations within the study sites. Total genomic DNA pooled from all sampling sites was extracted and analyzed by whole-genome shotgun sequencing. Analyses revealed three major kingdoms: bacteria, archaea and eukaryotes belonging to 3 phyla, 13 classes, 14 families, 9 orders, 14 genera, and 10 species. Proteobacteria, Betaproteobacteria, Comamonadaceae, Burkholdariales, and Arcobacter were the dominated phyla, class, family, order, genera, and species, respectively. The Kyoto Encyclopedia of Genes and Genomes indicated the highest number of genes involved in metabolism. The presence of carbohydrate metabolism genes and enzymes was used to infer organic pollutions from sewage and agricultural runoffs. Similarly, the presence of xylene and nutrotoluene degradation genes and enzyme was used to infer industrial pollution into the lake. Drug metabolism genes lend credence to the possibility of pharmaceutical pollutants in water. Taken together, there is a clear indication of massive pollution. In addition, carbohydrate-active enzymes were the most abundant and included genes in glycoside hydrolases. Shotgun metagenomic analyses conveyed an understanding of the microbial communities of the massively polluted aquatic ecosystem of Winam Gulf, Lake Vicoria, Kenya. The current study documents the presence of multiclass pollutants in Lake Victoria and reveals information that might be useful for a potential bioremediation strategy using the native microbial communities.

Highly selective hydropyrolysis of lignin waste to benzene, toluene and xylene in presence of zirconia supported iron catalyst

The use of lignin to produce Benzene, Toluene and Xylene (BTX) is a promising pathway to strength the economic case, over the production of advanced bio-fuels alone. In this work, Ce, Na, Pd and Fe supported on zirconium oxide were evaluated for the ex-situ hydropyrolysis (HyPy)/hydrodeoxygenation (HDO) of Etek lignin under mild conditions (600 °C, 1 atmosphere) towards the production of BTX. Fe/ZrO2 was able to selectively produce BTX (67 area%) and cycloalkenes (13.5 area%) and strongly deoxygenate the HyPy oil to about 5 wt% oxygen content, resulting in an oil with a carbon distribution of 85.5 % in C5-C10 hydrocarbons. The high selectivity of Fe/ZrO2 was related to the iron oxophilicity, the strong reduction potential of zero-valent iron, the good dispersion of Fe nanoparticles on the support and the presence of mesopores and acid sites, which enhanced the interactions between the reacting species and the catalyst surface.

Amidation of Polyethylene-Acrylic Acid Copolymer as Pour Point Depressants for Waxy Crude Oils

The present work aims to provide amine-modified polyethylene-acrylic acid (PEAA) copolymers as a pour point depressant (PPD) that will be evaluated for lower pour point of crude oil. For this, PEAA was amidated with butylamine and octadecylamine in the presence of xylene as a solvent at 150 °C for 10 hours to obtain copolymers PEAA/ODA and PEAA/BA. The copolymers were modified by amidation using the carboxyl groups of an ethylene-acrylic acid copolymer as reaction sites in reactions with RNH2. The resulting copoly-mers were purified and analyzed by FTIR spectroscopy. The modified PEAA copolymers were evaluated for their effectiveness as depressants for crude oils by pour point measurements at 50 ppm, 100 ppm and 200 ppm and rheological measurements at 100 ppm. The pour point measurements of the crude oil showed that octadecylamine-modified PEAA copolymer performed better than butylamine-modified and unmodified PEAA copolymer. The effectiveness of the modified copolymers compared to unmodified PEAA can be ex-plained by the polarity of the monoalkylamide groups in the peripheral substituents along the copolymer backbone, which plays a crucial role in preventing the agglomeration of wax crystals in crude oil.

Selectivity behaviour of two roof-shaped host compounds in the presence of xylene and ethylbenzene guest mixtures

α,α-Diphenyl-9,10-dihydro-9,10-ethanoanthracene-11-methanol possessed an enhanced selectivity for o-Xy when recrystallized from various xylene and EB mixed solvents (84.5–93.7%).

Isolation, identification and potential probiotic characterization of lactic acid bacteria from Thai traditional fermented food.

The probiotic potential of lactic acid bacteria (LAB) isolated from Thai traditional fermented food was investigated. Forty-two samples were collected from four markets in Phra Nakhon Si Ayutthaya Province. Out of 50 isolated LAB, 6 (a3, f4, f8, K1, K4 and K9) obtained from pla-ra and bamboo shoot pickle samples showed high tolerance to gastrointestinal tract conditions. These isolates were selected to identify and characterize their probiotic properties. Isolate a3 was identified as Weissella thailandensis, isolates f4 and f8 were identified as belonging to Enterococcus thailandicus and isolates K1, K4 and K9 were determined as Limosilactobacillus fermentum. All six LAB exhibited high autoaggregation ability (93.40–95.01%), while W. thailandensis isolate a3 showed potential for coaggregation in almost all the pathogenic bacteria tested. Cell-free supernatant (CFS) obtained from all isolates did not inhibit Staphylococcus aureus. CFS derived from L. fermentum isolate K4 showed the most efficient antimicrobial activity, in particular against Gram-negative bacteria, while L. fermentum isolate K4 presented high surface hydrophobicity in the presence of xylene and n-hexane. All LAB isolates were found to be resistant to clindamycin and nalidixic acid, whereas E. thailandicus isolate f8 exhibited resistance to most of the antibiotics tested. L. fermentum isolate K4 showed promise as a suitable probiotic candidate for future applications in the food industry due to tolerance to gastrointestinal tract conditions with high surface hydrophobicity and inhibited most of the pathogens tested.

The impact of interior construction on the indoor environmental quality

Abstract The presented paper deals with the evaluation of the indoor environmental quality (IEQ) in two apartment units in different phases of interior construction. The first apartment is in the initial phase of an unfurnished apartment and the second in the final phase of a fully furnished apartment. The results of IEQ monitoring indicate that in terms of thermal-humidity microclimate, the required legislative limits were met and the differences between the unfurnished and the fully furnished apartment were minimal. Only the operative temperature values were not in the legislative range. The average particulate matter (PM) concentrations of the two representative fractions (PM2.5 and PM10) were 21.10 μg/m3 and 564.72 μg/m3 for the unfurnished apartment and 4.67 μg/m3 and 68.15 μg/m3 for the furnished apartment. The legislative limit of 50 μg/m3 for PM10 was therefore significantly exceeded, especially in the case of an unfurnished apartment in the initial phase. The average TVOC concentration expressed in toluene equivalents was 1955 μg/m3 in a furnished apartment and 910 μg/m3 in an unfurnished apartment. Both of these values exceeded Mølhave’s recommended limit of 200 μg/m3. The presence of xylenes (51.19 μg/m3) and ethylbenzene (17.27 μg/m3) was detected in an unfurnished apartment. In addition to xylenes (171.63 μg/m3) and ethylbenzene (79.25 μg/m3), toluene (78.34 μg/m3) was also present in the furnished apartment. The concentrations of these compounds were below the legislative limits, except for ethylbenzene for which no legislative limits are set. The above results show that further surface treatment and furnishing of the apartment contribute to the increase of the VOC levels in the indoor environment. In the case of unfurnished apartment, workers are exposed not only to elevated concentrations of TVOC but also to elevated concentrations of PM10 and should therefore pay attention to the protection and safety of health during the work.

Component composition of dissolved organic compounds of sewage water of uzen’ oilfield

The composition of extracts of volatile dissolved organic compounds of the wastewater of the Ozen oilfield was studied by chromatography-mass spectrometry (GC/MS). It has been established that the main components are hydrocarbons. It should be noted the presence in the water of benzyl chloride (benzene chloride) -1.3%, the content of which is strictly regulated in oil. A low content of organic acids (palmitic acid) is observed. It should also be noted the presence of tertiary N, N-dimethyldodecanamine (C-12) upto 2.3% and N, N-dimethyltridecanamine (C-13), which are components of corrosion inhibitors. The presence of xylene, mesitylene, 1,2,3-trimethylbenzene and 2,6-dimethylnaphthalene indicates the possible use of the demulsifier type Tretolite. A significant amount of squalene, which is a natural biomarker of oils has also been discovered.

The hydrophobicity of enterobacteria and their co-aggregation with Enterococcus faecalis isolated from Serbian cheese.

In this paper, we investigated the hydrophobicity, ability to adhere to solvents and the pig epithelium and co-aggregation of members of family Enterobacteriaceae and Enterococcus faecalis KGPMF 49. The bacteria used in this study were isolated from traditionally made autochthonous cheese from Southeastern Serbia (Sokobanja). The percentage of adhered bacteria was different in three solvents (chloroform, ethyl acetate and xylene). The highest percentage was detected in the presence of chloroform, and the lowest percentage was detected in the presence of xylene (chloroform < ethyl acetate < xylene). A different degree of co-aggregation of enterobacteria with E. faecalis KGPMF 49 was observed. Klebsiella ornithinolytica KGPMF 8 demonstrated the highest percentage of co-aggregation with E. faecalis KGPMF49 (32.29%). Klebsiella pneumoniae KGPMF 13, K. ornithinolytica KGPMF 9 and Serratia marcescens biogp 1 KGPMF 19 were found to have the ability to adhere to the pig epithelium, whereas Escherichia coli KGPMF 22 showed no such ability. The ability to co-aggregate with other species and the ability to adhere to the pig epithelium are very important characteristics of the isolated bacteria.

Compounds N,N′-bis(9-cyclohexyl-9-xanthenyl)ethylenediamine and its thio derivative, N,N′-bis(9-cyclohexyl-9-thioxanthenyl)ethylenediamine, as potential hosts in the presence of xylenes and ethylbenzene: Conformational analyses and molecular modelling considerations

Two novel crystalline compounds, N,N′-bis(9-cyclohexyl-9-xanthenyl)ethylenediamine (OED) and its thio derivative, N,N′-bis(9-cyclohexyl-9-thioxanthenyl)ethylenediamine (SED), were designed and synthesized in our laboratories, and assessed for their potential as host compounds for the four C8 aromatic compounds, namely o-, m- and p-xylene (o-Xy, m-Xy, p-Xy), and ethylbenzene (EB). Despite the only difference between the two compounds being the heteroatoms in their B rings, immense behaviour differences were noted: only OED displayed host behaviour in these conditions, clathrating all but m-Xy, while SED failed to form complexes with any of the four organic solvents. These observations prompted an investigation into the conformations of OED and SED through single crystal diffraction (SCXRD) analyses as well as computational studies with surprising results. SCXRD was also employed to analyse the three complexes that successfully formed with OED, and thermal analyses (TA) assisted in understanding the selectivity behaviour of OED when presented with mixed guests.

Growth of indigenous bacteria Vibrio alginolyticus and Dietzia sp. isolated from the east coast of Algeria in the presence of monoaromatic hydrocarbons

East coast of Algeria suffers from several types of pollution, mainly hydrocarbons. The hydrocarbon-based bacteria of the littoral were investigated. 53 indigenous strains were isolated, identified according to morphological and biochemical nature. Dietzia sp. CNJ898 PLO4 and Vibrio alginolyticus PB-WC 11099 were selected for growth tests in the presence of monoaromatic hydrocarbons as a sole source of carbon and energy and total hydrocarbons at the end of growth. The results showed that both strains used monoaromatics to grow. The total hydrocarbons determined after growth showed that all monoaromatics were biodegraded with different rates. The maximum rate was obtained with Dietzia sp. in the presence of xylene with 4.33 mg C/dm 3 at the end of the process, followed by toluene with a level of 5.07 mg C/dm 3 and 5.60 mg C/dm 3 in the presence of Vibrio alginolyticus. The lowest degradation rate was obtained in the presence of benzene with Dietzia sp. with 15 mg C/dm 3 compared to the control, which was 27 mg C/dm 3 at the beginning of growth. The results obtained showed that both selected strains assimilated the monoaromatics tested and could be used for the bioremediation of the polluted littoral.

N,N′-Bis(9-phenyl-9-thioxanthenyl)ethylenediamine: Highly Selective Host Behavior in the Presence of Xylene and Ethylbenzene Guest Mixtures

Host compound N,N′-bis(9-phenyl-9-thioxanthenyl)ethylenediamine formed 1:1 host:guest complexes with o- and p-xylene, and ethylbenzene, when recrystallized from them. The meta-isomer was not included. Competition experiments using equimolar binary and ternary mixtures of the three xylenes demonstrated that this host is markedly selective for p-xylene (≥94% on both a milligram- and gram-scale), while 68% of this guest was extracted from an equimolar quaternary mixture of the three xylenes and ethylbenzene. This selectivity was also evident when guest ratios in binary mixtures containing p-xylene were varied. The observed high affinity for the para-isomer was explained using single crystal X-ray diffraction, Hirshfeld surface analysis and thermoanalytical experiments. Furthermore, the host was subjected to gas phase guests in order to establish whether the ability existed for complexation of these guests from the solid state.

Zinc(II) bis(dipyrromethenate)s-based «Оn–Off» fluorescent sensors for xylenes

This paper presents the results of spectral-luminescence research of binuclear zinc(II) helicates with deca-, octa-, and tetramethylsubstituted 3,3′-bis(dipyrromethene)s ([Zn2L2]) in binary mixtures of cyclohexane with m-, o- and p-xylene. Structure effects of [Zn2L2], and aromaticity criteria of analytes (HOMA, NICS, μ) on the fluorescence quenching efficiency of [Zn2L2] in the presence of xylenes was considered. It was found that decamethyl substituted 3,3′-bis(dipyrromethenate)s compared to octa-, and tetramethylsubstituted-analogs shows the highest fluorescence sensitivity to the presence of aromatic compounds. Quantum-chemical modeling showed that [Zn2L2] fluorescence quenching in the xylenes presence is caused by the formation of [Zn2L2An] (n = 1 or 2) supramolecular structures. High specificity of spectral-luminescent characteristics changing in the presence of xylenes provides the possibility of using [Zn2L2] helicates as new fluorescent sensors for trace amounts (6.5–99ppm) detection of methylbenzenes in organic media.

Effects of concentration and gas flow rate on the removal of gas-phase toluene and xylene mixture in a compost biofilter

The aim of this work was to study the performance of a compost/ceramic bead biofilter (6:4 v/v) for the removal of gas-phase toluene and xylene at different inlet loading rates (ILR). The inlet toluene (or) xylene concentrations were varied from 0.1 to 1.5gm−3, at gas flow rates of 0.024, 0.048 and 0.072m3h−1, respectively, corresponding to total ILR varying between 7 and 213gm−3h−1. Although there was mutual inhibition, xylene removal was severely inhibited by the presence of toluene than toluene removal by the presence of xylene. The biofilter was also exposed to transient variations such as prolonged periods of shutdown (30days) and shock loads to envisage the response and recuperating ability of the biofilter. The maximum elimination capacity (EC) for toluene and xylene were 29.2 and 16.4gm−3h−1, respectively, at inlet loads of 53.8 and 43.7gm−3h−1.

Reformation of hydrogen sulfide to hydrogen in the presence of xylene

Hydrogen sulfide is a hazardous gas from environmental, human health and equipment prospective. Hydrogen sulfide occurs naturally from crude oil and natural gas wells along with some other hydrocarbon impurities. Reformation of hydrogen sulfide without or with the presence of xylene (a common impurity present in hydrogen sulfide) has been investigated. Production of hydrogen concurrent with destruction of hydrogen sulfide provides a good alternative method to treat hydrogen sulfide. The role of xylene addition on the reformation of hydrogen sulfide was experimentally investigated. A laboratory-scale reactor was used to examine the effect of reactor temperature in the range of 1273–1573K and various inlet stream composition on the production of hydrogen and destruction of both hydrogen sulfide and xylene. Results showed enhanced hydrogen production and higher hydrogen sulfide destruction at temperatures above 1273K. Xylene was destructed completely at a relatively low temperature of 1373K. Carbon disulfide formation increased with increase in temperature for all the inlet compositions of hydrogen sulfide and xylene examined. Reducing the formation of CS2 and also mitigation of carbon deposition by reducing the amounts of carbon introduced to the reactor were investigated and quantified experimentally. The most favorable operational conditions for reaction between hydrogen sulfide and xylene were established. The results showed new potential of this binary mixture dissociation as an alluring treatment method of hydrogen sulfide.

Synthesis of Xylylene-Bridged Periodic Mesoporous Organosilicas and Related Hollow Spherical Nanoparticles.

A variety of organosilicas with p-xylylene bridging groups in the framework were synthesized using Pluronic F127 triblock copolymer as a micellar template under moderately acidic conditions in the presence of xylene as a micelle swelling agent. The resulting materials were characterized by using nitrogen adsorption, small-angle X-ray scattering, transmission electron microscopy, and (29)Si and (13)C cross-polarization magic angle spinning NMR. As the ratio of the organosilica precursor to Pluronic F127 was decreased, the structure evolved from highly ordered periodic mesoporous organosilica (PMO) to weakly ordered PMO, loosely aggregated hollow organosilica nanospheres, and finally to a significantly aggregated disordered structure. The highly ordered PMO with primarily face-centered cubic structure was effectively a closed-pore material. However, the weakly ordered variant exhibited large-diameter (∼15 nm) spherical mesopores, which were accessible after calcination under appropriate conditions or after extraction. The hollow nanospheres had readily accessible, uniform inner cavities whose size was readily tunable by adjusting the amount of the swelling agent used. It was also possible to convert the organosilica nanospheres into hollow silica nanospheres with inaccessible (closed) mesopores. The formation of distinct well-defined morphologies with spherical mesopores for an organosilica with large bridging groups in the framework shows that block-copolymer-surfactant templating is a powerful and versatile method for controlling the nanoscale structures of these remarkable materials.

Nanostructure Directed Detection of Acidic SO2 and Its Transformation to Basic Character: Suggested Transient Formation of SO3−, Impedance by Xylene

Using nanostructure metal oxide decorated interfaces we study the conductometric response of PS to SO2 in a UHP N2 flow and in the presence of xylene. We have evaluated the response of the porous silicon (PS) interface and the enhancement of the interface decorated with SnOx, NiO, CuxO, and AuxO (x ≫ 1) nanostructured deposits. SO2, which acts as a Lewis acid, appears to be rapidly converted upon interaction to form a basic analyte which interacts with the nanostructure decorated PS interface. This process can be monitored through the inversion of conductometric response .We suggest that SO2 interacts and forms the transient ion, SO3−. The process can be inhibited in the presence of xylene. The response of an SnOx and AuxO decorated interface to this suggested intermediate is found to dominate those of NiO and CuxO.