Displaying publications 1 - 20 of 44 in total

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  1. Ethylbenzene and toluene interactions with biochar from municipal solid waste in single and dual systems
    Jayawardhana Y, Keerthanan S, Lam SS, Vithanage M
    Environ Res, 2021 06;197:111102.
    PMID: 33798520 DOI: 10.1016/j.envres.2021.111102
    The present study investigated adsorptive removal of toluene and ethylbenzene from the aqueous media via using biochar derived from municipal solid waste (termed "MSW-BC") in a single and binary contaminant system at 25-45 °C. The adsorption was evaluated at different pH (3-10), experimental time (up to 24 h), and initial adsorbate concentrations (10-600 μg/L) in single and binary contaminant system. A fixed-bed column experiment was also conducted using MSW-BC (0.25%) and influent concentration of toluene and ethylbenzene (4 mg/L) at 2 mL/min of flow rate. The adsorption of toluene and ethylbenzene on the MSW-BC was mildly dependent on the pH, and the peak adsorption ability (44-47 μg/g) was recorded at a baseline pH of ~8 in mono and dual contaminant system. Langmuir and Hill are the models that match the isotherm results in a single contaminant environment for both toluene (R2 of 0.97 and 0.99, respectively) and ethylbenzene (R2 of 0.99 and 0.99, respectively) adsorption. In the binary system, the isotherm models matched in the order of Langmuir > Hill > Freundlich for toluene, whereas Hill > Freundlich > Langmuir for ethylbenzene. The adsorption in the batch experiment was likely to take place via cooperative and multilayer adsorption onto MSW-BC involving hydrophobic, π- π and n- π attractions, specific interaction such as hydrogen-π and cation-π interactions, and van der Waals interactions. The thermodynamic results indicate exothermic adsorption occurred by physical attractions between toluene and ethylbenzene, and MSW-BC. The breakthrough behavior of toluene and ethylbenzene was successfully described with Yoon-Nelson and Thomas models. The data demonstrate that the low-cost adsorbent derived from the municipal solid waste can be utilized to remove toluene and ethylbenzene in landfill leachate.
    Matched MeSH terms: Toluene*
  2. Extraction and reimmobilization of used commercial lipase from industrial waste
    Mokhtar NF, Rahman RNZ, Sani F, Ali MS
    Int J Biol Macromol, 2021 Apr 15;176:413-423.
    PMID: 33556405 DOI: 10.1016/j.ijbiomac.2021.02.001
    In industrial application, immobilized lipase are typically not reused and served as industrial waste after a certain process is completed. The capacity on the reusability of the spent lipase is not well studied. This current study embarks on reusing the remaining lipase from the spent immobilized enzyme. Active lipases were recovered using a simple reverse micellar extraction (RME). RME is the extraction process of targeted biomolecules using an organic solvent and a surfactant. This method was the first attempt reported on the recovery of the lipase from the used immobilized lipase. RME of the spent lipase was done using the nonionic Triton X-100 surfactant and toluene. Various parameters were optimized to maximize the lipase recovery from the used immobilized lipase. The optimum forward extraction condition was 0.075 M KCl, and backward conditions were at 0.15 M Triton X-100/toluene (pH 6, 2 M KCl) with recovery of 66%. The extracted lipase was immobilized via simple adsorption into the ethanol pretreated carrier. The optimum conditions of immobilization resulted in 96% of the extracted lipase was reimmobilized. The reimmobilized lipase was incubated for 20 h in pH 6 buffer at 50 °C of water bath shaker. The reimmobilized lipase still had 27% residual activity after 18 h of incubation, which higher thermal stability compared to the free lipase. In conclusion, the free lipase was successfully extracted from the spent immobilized lipase and reimmobilized into the new support. It exhibited high thermal stability, and the reusability of the spent lipase will promote continued use of industrial lipase and reduce the cost of the manufacturing process.
    Matched MeSH terms: Toluene/chemistry
  3. Fulltext A case study: Chemical health risk assessment in three footwear small industries in Bogor-Indonesia year 2019
    Savira YM, Tejamaya M, Putri AA
    Gac Sanit, 2021 12 22;35 Suppl 2:S374-S378.
    PMID: 34929854 DOI: 10.1016/j.gaceta.2021.10.054
    OBJECTIVE: This study aimed to analyse the health risks related to the use of chemicals among workers in small footwear factories.

    METHODS: This was a descriptive case study conducted in three selected small footwear factories located in Ciomas, Bogor, Indonesia. The assessment was conducted using the chemical health risk assessment method by the Department of Safety and Health Malaysia Year 2018.

    RESULTS: Results showed that the level of risk of chemicals through inhalation fell on the moderate and high-risk categories, indicating that high exposure could lead to carcinogenic effects. Dermal exposure was categorised as moderate risk, causing such health effects as skin and eye irritation.

    CONCLUSION: Factory X, Y, and Z have been found to have a significant risk of hazardous chemical exposure (i.e., benzene and toluene), specifically at the glueing stations, either from inhalation or dermal contact.

    Matched MeSH terms: Toluene/analysis
  4. Solvent abuse: a case report and a review
    Sarvesvaran R, Hasnan J
    Malays J Pathol, 1994 Dec;16(2):167-71.
    PMID: 9053568
    The deliberate inhalation of solvents among children and adolescents "for kicks" is becoming more common in the West. It was generally regarded as a relatively harmless practice and consequently little attention had been paid to the isolation of the toxic agent from the variety of substances used. It is now well recognised that solvent abuse not only can result in sudden death but also cause pathological changes to the liver, kidney, brain, heart and lungs. A case of toluene associated death in Malaysia is discussed both from a medico-legal and pathological standpoint.
    Matched MeSH terms: Toluene*
  5. Toluene-induced leukodystrophy from glue sniffing
    Lau YH, Mawardi AS, Zain NR, Viswanathan S
    Pract Neurol, 2021 Oct;21(5):439-441.
    PMID: 34039751 DOI: 10.1136/practneurol-2021-002942
    A 33-year-old man with a history of chronic toluene abuse through glue sniffing, developed tremors, cerebellar signs and cognitive decline. MR scan of the brain showed global cerebral and cerebellar atrophy with symmetrical T2-weighted hypointensities in the basal ganglia, thalami and midbrain. After stopping glue sniffing, his tremors, ataxia of gait, speech and cognition partially improved. Early recognition and intervention of toluene-induced leukodystrophy could prevent ongoing morbidity and premature mortality.
    Matched MeSH terms: Toluene/adverse effects
  6. Effective toluene oxidation under ozone over mesoporous MnOx/γ-Al2O3 catalyst prepared by solvent deficient method: Effect of Mn precursors on catalytic activity
    Reddy KHP, Kim BS, Lam SS, Jung SC, Song J, Park YK
    Environ Res, 2021 04;195:110876.
    PMID: 33592225 DOI: 10.1016/j.envres.2021.110876
    In this study, the role of manganese precursors in mesoporous (meso) MnOx/γ-Al2O3 catalysts was examined systematically for toluene oxidation under ozone at ambient temperature (20 °C). The meso MnOx/γ-Al2O3 catalysts developed with Mn(CH3COO)2, MnCl2, Mn(NO3)2.4H2O and MnSO4 were prepared by an innovative single step solvent-deficient method (SDM); the catalysts were labeled as MnOx/Al2O3(A), MnOx/Al2O3(C), MnOx/Al2O3(N), and MnOx/Al2O3(S), respectively. Among all, MnOx/Al2O3(C) showed superior performance both in toluene removal (95%) as well as ozone decomposition (88%) followed by acetate, nitrate and sulphated precursor MnOx/Al2O3. The superior performance of MnOx/Al2O3(C) in the oxidation of toluene to COx is associated with the ozone decomposition over highly dispersed MnOx in which extremely active oxygen radicals (O2-, O22- and O-) are generated to enhance the oxidation ability of the catalysts greatly. In addition, toluene adsorption over acid support played a vital role in this reaction. Hence, the properties such as optimum Mn3+/Mn4+ ratio, acidic sites, and smaller particle size (≤2 nm) examined by XPS, TPD of NH3, and TEM results are playing vital role in the present study. In summary, the MnOx/Al2O3 (C) catalyst has great potential in environmental applications particularly for the elimination of volatile organic compounds with low loading of manganese developed by SDM.
    Matched MeSH terms: Toluene
  7. Fulltext Crystal structure of 2-(3-bromo-phen-yl)-1,3-di-thiane
    Zukerman-Schpector J, Caracelli I, Stefani HA, Gozhina O, Tiekink ER
    Acta Crystallogr E Crystallogr Commun, 2015 Mar 1;71(Pt 3):o179-80.
    PMID: 25844236 DOI: 10.1107/S2056989015002832
    In the title compound, C10H11BrS2, the 1,3-di-thiane ring has a chair conformation with the 1,4-disposed C atoms being above and below the remaining four atoms. The bromo-benzene ring occupies an equatorial position and forms a dihedral angle of 86.38 (12)° with the least-squares plane through the 1,3-di-thiane ring. Thus, to a first approximation the mol-ecule has mirror symmetry with the mirror containing the bromo-benzene ring and the 1,4-disposed C atoms of the 1,3-di-thiane ring. In the crystal, mol-ecules associate via weak methyl-ene-bromo-benzene C-H⋯π and π-π [Cg⋯Cg = 3.7770 (14) Å for centrosymmetrically related bromo-benzene rings] inter-actions, forming supra-molecular layers parallel to [10-1]; these stack with no specific inter-molecular inter-actions between them.
    Matched MeSH terms: Toluene
  8. Fulltext Synergistic interaction of metal loaded multifactorial nanocatalysts over bifunctional transalkylation for environmental applications
    Altındaş C, Sher F, Smječanin N, Lima EC, Rashid T, Hai IU, et al.
    Environ Res, 2023 Jan 01;216(Pt 1):114479.
    PMID: 36208784 DOI: 10.1016/j.envres.2022.114479
    A feasible and cost-effective process for utilization of toluene and heavy reformate is the conversion of its streams by transalkylation reaction into highly valuable xylenes. The process is usually catalysed by zeolites and the challenges to overcome in transalkylation of heavy reformate with toluene over zeolites are their selectivity, activity, long-term stability, and coke formation. Current study aimed to investigate xylenes production by transalkylation reaction on the synthesized metal-doped zeolite catalysts and to characterize prepared catalysts by FTIR, SEM, EDS and BET analysis. Toluene/heavy reformate modelled mixture was utilized as a feed. For the first time Beta and ZSM-5 catalysts with 10% (w/w) cerium and 0.1% (w/w) palladium were synthesized by calcination and wet impregnation method. Catalytic tests were performed by continuous-flow gas/solid catalytic fixed bed reactor at atmospheric pressure, 2 h-1 and 5 h-1 and 250, 300, 350 and 400 °C. Experimental results revealed that the highest heavy reformate conversion (98.94%) and toluene conversion (9.82%) were obtained over H-ZSM-5, at 400 °C and 2 h-1 WHSV. The highest xylene selectivity (11.53) was achieved over H-ZSM-5, and the highest p-xylene percentage (62.40%), using Ce-ZSM-5 catalyst. ZSM-5 catalysts showed more resistance to coke deposition than Beta zeolites. The present study delivers novel approach and catalysts, which have immense potential for developing safer and inexpensive transalkylation process in industry.
    Matched MeSH terms: Toluene
  9. Study on kinetic model of microwave thermocatalytic treatment of biomass tar model compound
    Anis S, Zainal ZA
    Bioresour Technol, 2014 Jan;151:183-90.
    PMID: 24231266 DOI: 10.1016/j.biortech.2013.10.065
    Kinetic model parameters for toluene conversion under microwave thermocatalytic treatment were evaluated. The kinetic rate constants were determined using integral method based on experimental data and coupled with Arrhenius equation for obtaining the activation energies and pre-exponential factors. The model provides a good agreement with the experimental data. The kinetic model was also validated with standard error of 3% on average. The extrapolation of the model showed a reasonable trend to predict toluene conversion and product yield both in thermal and catalytic treatments. Under microwave irradiation, activation energy of toluene conversion was lower in the range of 3-27 kJ mol(-1) compared to those of conventional heating reported in the literatures. The overall reaction rate was six times higher compared to conventional heating. As a whole, the kinetic model works better for tar model removal in the absence of gas reforming within a level of reliability demonstrated in this study.
    Matched MeSH terms: Toluene/chemistry
  10. Enhanced toluene removal using granular activated carbon and a yeast strain Candida tropicalis in bubble-column bioreactors
    Ahmed Z, Hwang SJ, Shin SK, Song J
    J Hazard Mater, 2010 Apr 15;176(1-3):849-55.
    PMID: 20031312 DOI: 10.1016/j.jhazmat.2009.11.114
    The yeast strain Candida tropicalis was used for the biodegradation of gaseous toluene. Toluene was effectively treated by a liquid culture of C. tropicalis in a bubble-column bioreactor, and the toluene removal efficiency increased with decreasing gas flow rate. However, toluene mass transfer from the gas-to-liquid phase was a major limitation for the uptake of toluene by C. tropicalis. The toluene removal efficiency was enhanced when granular activated carbon (GAC) was added as a fluidized material. The GAC fluidized bioreactor demonstrated toluene removal efficiencies ranging from 50 to 82% when the inlet toluene loading was varied between 13.1 and 26.9 g/m(3)/h. The yield value of C. tropicalis ranged from 0.11 to 0.21 g-biomass/g-toluene, which was substantially lower than yield values for bacteria reported in the literature. The maximum elimination capacity determined in the GAC fluidized bioreactor was 172 g/m(3)/h at a toluene loading of 291 g/m(3)/h. Transient loading experiments revealed that approximately 50% of the toluene introduced was initially adsorbed onto the GAC during an increased loading period, and then slowly desorbed and became available to the yeast culture. Hence, the fluidized GAC mediated in improving the gas-to-liquid mass transfer of toluene, resulting in a high toluene removal capacity. Consequently, the GAC bubble-column bioreactor using the culture of C. tropicalis can be successfully applied for the removal of gaseous toluene.
    Matched MeSH terms: Toluene/metabolism*
  11. Fulltext Removal of toluene from aqueous solutions using oil palm shell based activated carbon: equilibrium and kinetics study
    Kwong, W. Z., Tan, I. A. W., Rosli, N. A., Lim, L. L. P.
    Pertanika Journal of Science & Technology, 2014;22(2):577-585.
    MyJurnal
    This study is an attempt to investigate the adsorption of petroleum hydrocarbon (toluene) from aqueous solutions using granular activated carbon (GAC) synthesized from oil palm shell (OPS) (referred as OPSbased GAC). This study involved a series of batch experiments to determine the adsorption equilibrium and kinetics. The batch experiments were conducted by shaking 200 mL toluene solution containing 0.4 g GAC (initial concentrations of 5, 15, 25 and 30 mg/L) at 180 rpm at 30°C. The OPS-based GAC achieved more than 80% toluene removal in all the experiments. The adsorption capacity of the OPSbased GAC estimated using Freundlich isotherm was 6.039 mg/g (L/mg)1/n. The adsorption kinetic study showed that the adsorption of toluene was of chemisorption as the experimental data fitted better to the pseudo-second-order kinetic model than the pseudo-first-order kinetic model.
    Matched MeSH terms: Toluene
  12. Fulltext Advancement in Benthic Microbial Fuel Cells toward Sustainable Bioremediation and Renewable Energy Production
    Umar MF, Rafatullah M, Abbas SZ, Mohamad Ibrahim MN, Ismail N
    Int J Environ Res Public Health, 2021 Apr 06;18(7).
    PMID: 33917378 DOI: 10.3390/ijerph18073811
    Anthropogenic activities are largely responsible for the vast amounts of pollutants such as polycyclic aromatic hydrocarbons, cyanides, phenols, metal derivatives, sulphides, and other chemicals in wastewater. The excess benzene, toluene and xylene (BTX) can cause severe toxicity to living organisms in wastewater. A novel approach to mitigate this problem is the benthic microbial fuel cell (BMFC) setup to produce renewable energy and bio-remediate wastewater aromatic hydrocarbons. Several mechanisms of electrogens have been utilized for the bioremediation of BTX through BMFCs. In the future, BMFCs may be significant for chemical and petrochemical industry wastewater treatment. The distinct factors are considered to evaluate the performance of BMFCs, such as pollutant removal efficiency, power density, and current density, which are discussed by using operating parameters such as, pH, temperature and internal resistance. To further upgrade the BMFC technology, this review summarizes prototype electrode materials, the bioremediation of BTX, and their applications.
    Matched MeSH terms: Toluene
  13. Profile of solvent abusers (glue sniffers) in East Malaysia
    Zabedah MY, Razak M, Zakiah I, Zuraidah AB
    Malays J Pathol, 2001 Dec;23(2):105-9.
    PMID: 12166590
    Solvent abuse is deliberate sniffing of an organic solvent for the intention of altering the physiological state of the individual. It is also commonly known as glue sniffing because glue is the most commonly abused substance. This form of substance abuse is widespread throughout the world and usually popular among secondary school children and young adults because of its easy availability and it is cheaper compared with most drugs of abuse. In Malaysia this problem has been recognized especially among the children in East Malaysia. In this study, 37 children and young adults from or around Kota Kinabalu, Sabah were referred to Bukit Padang Psychiatric Hospital by the Anti-drug Task force for suspected solvent abuse. These children were interviewed using questionaire and examined physically. Blood and urine were analysed for toluene and hippuric acid. 27 of the children, age ranging between 8 and 20 years, willingly admitted to sniffing glue for a period between a few months to 2 years. Most of them were children of Fillipino illegal immigrants in Kota Kinabalu. Biochemical parameters were found to be normal. Two of them were pale with low hemoglobin and 7 had eosinophilia. Haematuria and proteinuria were found in 21 children (78%). 16 blood samples with toluene levels ranging from 0.3 to 41 microg/ml and 10 urine samples have elevated urinary hippuric acid levels ranging from 1.2 to 7.4 mg/ml. Strong positive correlation was noted between mean blood toluene levels and duration of abuse.
    Matched MeSH terms: Toluene/blood; Toluene/urine
  14. BTEX compositions and its potential health impacts in Malaysia
    Latif MT, Abd Hamid HH, Ahamad F, Khan MF, Mohd Nadzir MS, Othman M, et al.
    Chemosphere, 2019 Dec;237:124451.
    PMID: 31394440 DOI: 10.1016/j.chemosphere.2019.124451
    This study aims to determine the composition of BTEX (benzene, toluene, ethylbenzene and xylene) and assess the risk to health at different sites in Malaysia. Continuous monitoring of BTEX in Kuala Lumpur City Centre, Kuala Terengganu, Kota Kinabalu and Fraser Hill were conducted using Online Gas Chromatograph. For comparison, BTEX at selected hotspot locations were determined by active sampling method using sorbent tubes and Thermal Desorption Gas Chromatography Mass Spectrometry. The hazard quotient (HQ) for non-carcinogenic and the life-time cancer risk (LTCR) of BTEX were calculated using the United States Environmental Protection Agency (USEPA) health risk assessment (HRA) methods. The results showed that the highest total BTEX concentrations using continuous monitoring were recorded in the Kuala Lumpur City Centre (49.56 ± 23.71 μg/m3). Toluene was the most dominant among the BTEX compounds. The average concentrations of benzene ranged from 0.69 ± 0.45 μg/m3 to 6.20 ± 3.51 μg/m3. Measurements using active sampling showed that BTEX concentrations dominated at the roadside (193.11 ± 114.57 μg/m3) in comparison to petrol station (73.08 ± 30.41 μg/m3), petrochemical industry (32.10 ± 13.13 μg/m3) and airport (25.30 ± 6.17 μg/m3). Strong correlations among BTEX compounds (p<0.01, r>0.7) at Kuala Lumpur City Centre showed that BTEX compounds originated from similar sources. The values of HQ at all stations were <1 indicating the non-carcinogenic risk are negligible and do not pose threats to human health. The LTCR value based on benzene inhalation (1.59 × 10-5) at Kuala Lumpur City Centre were between 1 × 10-4 and 1 × 10-5, representing a probable carcinogenic risk.
    Matched MeSH terms: Toluene/analysis*; Toluene/toxicity
  15. Removal of VOCs from gas streams with double perovskite-type catalysts
    Pan KL, Pan GT, Chong S, Chang MB
    J Environ Sci (China), 2018 Jul;69:205-216.
    PMID: 29941256 DOI: 10.1016/j.jes.2017.10.012
    Double perovskite-type catalysts including La2CoMnO6 and La2CuMnO6 are first evaluated for the effectiveness in removing volatile organic compounds (VOCs), and single perovskites (LaCoO3, LaMnO3, and LaCuO3) are also tested for comparison. All perovskites are tested with the gas hourly space velocity (GHSV) of 30,000hr-1, and the temperature range of 100-600°C for C7H8 removal. Experimental results indicate that double perovskites have better activity if compared with single perovskites. Especially, toluene (C7H8) can be completely oxidized to CO2 at 300°C as La2CoMnO6 is applied. Characterization of catalysts indicates that double perovskites own unique surface properties and are of higher amounts of lattice oxygen, leading to higher activity. Additionally, apparent activation energy of 68kJ/mol is calculated using Mars-van Krevelen model for C7H8 oxidation with La2CoMnO6 as catalyst. For durability test, both La2CoMnO6 and La2CuMnO6 maintain high C7H8 removal efficiencies of 100% and 98%, respectively, at 300°C and 30,000hr-1, and they also show good resistance to CO2 (5%) and H2O(g) (5%) of the gas streams tested. For various VOCs including isopropyl alcohol (C3H8O), ethanal (C2H4O), and ethylene (C2H4) tested, as high as 100% efficiency could be achieved with double perovskite-type catalysts operated at 300-350°C, indicating that double perovskites are promising catalysts for VOCs removal.
    Matched MeSH terms: Toluene/analysis; Toluene/chemistry
  16. Fulltext Improvement of physicochemical characteristics of monoepoxide linoleic acid ring opening for biolubricant base oil
    Salimon J, Salih N, Abdullah BM
    J Biomed Biotechnol, 2011;2011:196565.
    PMID: 22131799 DOI: 10.1155/2011/196565
    For environmental reasons, a new class of environmentally acceptable and renewable biolubricant based on vegetable oils is available. In this study, oxirane ring opening reaction of monoepoxide linoleic acid (MEOA) was done by nucleophilic addition of oleic acid (OA) with using p-toluene sulfonic acid (PTSA) as a catalyst for synthesis of 9(12)-hydroxy-10(13)-oleoxy-12(9)-octadecanoic acid (HYOOA) and the physicochemical properties of the resulted HYOOA are reported to be used as biolubricant base oils. Optimum conditions of the experiment using D-optimal design to obtain high yield% of HYOOA and lowest OOC% were predicted at OA/MEOA ratio of 0.30 : 1 (w/w), PTSA/MEOA ratio of 0.50 : 1 (w/w), reaction temperature at 110°C, and reaction time at 4.5 h. The results showed that an increase in the chain length of the midchain ester resulted in the decrease of pour point (PP) -51°C, increase of viscosity index (VI) up to 153, and improvement in oxidative stability (OT) to 180.94°C.
    Matched MeSH terms: Toluene/analogs & derivatives; Toluene/chemistry
  17. Start-up, performance and optimization of a compost biofilter treating gas-phase mixture of benzene and toluene
    Rene ER, Kar S, Krishnan J, Pakshirajan K, López ME, Murthy DV, et al.
    Bioresour Technol, 2015 Aug;190:529-35.
    PMID: 25827361 DOI: 10.1016/j.biortech.2015.03.049
    The performance of a compost biofilter inoculated with mixed microbial consortium was optimized for treating a gas-phase mixture of benzene and toluene. The biofilter was acclimated to these VOCs for a period of ∼18d. The effects of concentration and flow rate on the removal efficiency (RE) and elimination capacity (EC) were investigated by varying the inlet concentration of benzene (0.12-0.95g/m(3)), toluene (0.14-1.48g/m(3)) and gas-flow rate (0.024-0.072m(3)/h). At comparable loading rates, benzene removal in the mixture was reduced in the range of 6.6-41% in comparison with the individual benzene degradation. Toluene removal in mixture was even more affected as observed from the reductions in REs, ranging from 18.4% to 76%. The results were statistically interpreted by performing an analysis of variance (ANOVA) to elucidate the main and interaction effects.
    Matched MeSH terms: Toluene/isolation & purification*; Toluene/chemistry
  18. Effect of Bulky Functional Groups on Donor and Acceptor Interactions and their Photoluminescence Properties
    Woon KL, Mustapa SAS, Mohd Jamel NS, Lee VS, Zakaria MZ, Ariffin A
    Chemphyschem, 2020 Sep 17.
    PMID: 32940952 DOI: 10.1002/cphc.202000612
    Material designs that use donor and acceptor units are often found in organic optoelectronic devices. Molecular level insight into the interactions between donors and acceptors are crucial for understanding how such interactions can modify the optical properties of the organic optoelectronic materials. In this paper, tris(4-(tert-butyl)phenyl)amine (pTPA) was synthesized as a donor in order to compare with unmodified triphenylamine (TPA) in a donor-acceptor system by having 2,4,6-triphenyl-1,3,5-triazine (TRZ) as an acceptor. Dimerization of donors and acceptors occurred in solvent when the concentration of solute is high. At 0 K, using a polarizable continuum model, the nitrogen atom of TPA is found to stack on top of the center of triazine of TRZ, whereas such alignment is offset in pTPA and TRZ. We attributed such alignment in TPA-TRZ as the result of attractive interactions between partial localization of 2pz electrons at the nitrogen atom of TPA and the π deficiency of triazine in TPA-TRZ. By taking into account random motions of the solvent effect at 300 K in quantum molecular dynamics and classical molecular dynamics simulations to interpret the marked difference in emission spectra between TPA-TRZ and pTPA-TRZ, it was revealed that the attractive interaction between pTPA and TRZ in toluene is weaker than TPA and TRZ. Because of the weaker attractive interaction between pTPA and TRZ in toluene, the dimers adopted numerous ground state conformations resulting in broad emission bands superimposed with multiple small Gaussian peaks. This is in contrast to TPA-TRZ which has only one dominant dimer conformation. This study demonstrates that the strength of intermolecular interactions between donors and acceptors should be taken into consideration in designing supramolecular structures.
    Matched MeSH terms: Toluene
  19. Fulltext Comparative Study of Aromatic and Cycloaliphatic Isocyanate Effects on Physico-Chemical Properties of Bio-Based Polyurethane Acrylate Coatings
    Mudri NH, Abdullah LC, Aung MM, Salleh MZ, Awang Biak DR, Rayung M
    Polymers (Basel), 2020 Jul 03;12(7).
    PMID: 32635384 DOI: 10.3390/polym12071494
    Crude jatropha oil (JO) was modified to form jatropha oil-based polyol (JOL) via two steps in a chemical reaction known as epoxidation and hydroxylation. JOL was then reacted with isocyanates to produce JO-based polyurethane resin. In this study, two types of isocyanates, 2,4-toluene diisocyanate (2,4-TDI) and isophorone diisocyanate (IPDI) were introduced to produce JPUA-TDI and JPUA-IPDI respectively. 2,4-TDI is categorised as an aromatic isocyanate whilst IPDI is known as a cycloaliphatic isocyanate. Both JPUA-TDI and JPUA-IPDI were then end-capped by the acrylate functional group of 2-hydroxyethyl methacrylate (HEMA). The effects of that isocyanate structure were investigated for their physico, chemical and thermal properties. The changes of the functional groups during each synthesis step were monitored by FTIR analysis. The appearance of urethane peaks was observed at 1532 cm-1, 1718 cm-1 and 3369 cm-1 while acrylate peaks were detected at 815 cm-1 and 1663 cm-1 indicating that JPUA was successfully synthesised. It was found that the molar mass of JPUA-TDI was doubled compared to JPUA-IPDI. Each resin showed a similar degradation pattern analysed by thermal gravimetric analysis (TGA). For the mechanical properties, the JPUA-IPDI-based coating formulation exhibited a higher hardness value but poor adhesion compared to the JPUA-TDI-based coating formulation. Both types of jatropha-based polyurethane acrylate may potentially be used in an ultraviolet (UV) curing system specifically for clear coat surface applications to replace dependency on petroleum-based chemicals.
    Matched MeSH terms: Toluene 2,4-Diisocyanate
  20. Effect of rice husk surface modification by LENR the on mechanical properties of NR/HDPE reinforced rice husk composite
    Rahmadini Syafri, Ishak Ahmad, Ibrahim Abdullah
    Sains Malaysiana, 2011;40:1123-1127.
    Surface modification of rice husk (RH) with alkali pre-treatment (NaOH solution 5% w/v) was carried out at the initial state to investigate the effect of surface treatment of fibre on the surface interaction between fibre and rubber. Further modification of RH surfaces after alkali treatment was using Liquid Epoxidized Natural Rubber (LENR) coating at three concentrations, 5%, 10%, and 20% wt LENR solution in toluene. Interfacial morphology and chemical reactions between RH fibre and rubber were analyzed by FTIR and Scanning Electron Microscope (SEM). It was found that 10% wt LENR solution gave the optimum interaction between fibre and rubber. Matrix and composite blends derived from 60% natural rubber (NR), 40% high density polyethylene (HDPE) reinforced with RH fibre were prepared using an internal mixer (Brabender Plasticoder). Result showed that pre-treatment of RH treated with 5% NaOH followed by treatment with 10% LENR solution given the maximum interaction between fibre and matrix that gave rise to better mechanical properties of the composites.
    Matched MeSH terms: Toluene
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