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Murray J Thomson – 1st expert on this subject based on the ideXlab platform
the effects of naphthalene addition to Alkylbenzenes on soot formationCombustion and Flame, 2020Co-Authors: Murray J ThomsonAbstract:
Abstract Naphthalene and Alkylbenzenes are present in practical transportation fuels. This study investigates the impact of naphthalene addition to Alkylbenzenes on soot formation. Naphthalene was added to two kinds of Alkylbenzenes, namely, 1,2,4-trimethylbenzene and n-propylbenzene. Because they are isomers, the effect of molecular structure is isolated. The sooting characteristics of naphthalene-added Alkylbenzenes are compared to pure Alkylbenzenes in laminar coflow flames. The fuel and carbon mass flow rates were kept constant for all cases. The soot volume fraction measurements show that n-propylbenzene is sensitive to naphthalene addition. In contrast, no significant changes in soot volume fraction were observed for the 1,2,4-trimethylbenzene flames. A slight increase in primary particle diameter was observed for both naphthalene-added n-propylbenzene and 1,2,4-trimethylbenzene, suggesting that naphthalene promotes soot surface growth. The calculated number densities show that naphthalene addition promotes soot nucleation for n-propylbenzene but not for 1,2,4-trimethylbenzene. The flames were simulated with the CoFlame code with the CRECK mechanism. The model partially agrees with the experimental results, as the model agrees with the case of 1,2,4-trimethylbenzene but underestimates the effect of naphthalene addition to n-propylbenzene. More understanding of the PAH formation beyond naphthalene is required. In conclusion, the study suggests that the effect of naphthalene addition on soot formation is fuel-type dependent.
the chemical structure effects of Alkylbenzenes on soot formation in a laminar co flow flameCombustion and Flame, 2019Co-Authors: Tongfeng Zhang, Murray J ThomsonAbstract:
Abstract Alkylbenzene isomers are often used in transportation fuel surrogates but have different sooting tendencies. There is a need to understand how their chemical structures affect the soot formation mechanism. In this study, the chemical structure effects of Alkylbenzenes (1,2,4-trimethylbenzene (124TMB) and n-propylbenzene (PBZ)) on soot formation in a laminar diffusion flame were experimentally and numerically investigated. In the experiment, the optical time-resolved laser-induced incandescence (LII) and spectral soot emission (SSE) diagnostics were used to measure radial soot volume fraction, primary particle diameter and flame temperature profiles. The radial number density was also experimentally derived. The results are consistent with the literature as 124TMB exhibits higher soot concentration than PBZ. From the analyses of the primary particle diameters and the derived number density, this is caused by the higher soot nucleation rate for 124TMB. This conclusion is supported by numerical modeling, which utilized the detailed CoFlame code with a moderately reduced CRECK mechanism. The simulation results show that 124TMB has earlier soot inception and Polycyclic Aromatic Hydrocarbon (PAH) addition than PBZ. Consistent with both earlier soot inception and PAH addition, the 124TMB model predicts earlier pyrene (A4) formation, suggesting 124TMB has alternative reaction pathways for pyrene formation. The reaction pathway analysis suggests that pyrene is formed via the aromatic radical recombination route, as opposed to the conventional HACA mechanism. Bypassing the formation of the second ring could be the reason for 124TMB having earlier soot nucleation. In contrast, the PBZ model predicts that the formation of pyrene follows the slower HACA pathways, leading to later soot nucleation.
Hideshige Takada – 2nd expert on this subject based on the ideXlab platform
distribution of linear Alkylbenzenes labs in riverine and coastal environments in south and southeast asiaWater Research, 2004Co-Authors: Kei O Isobe, Mohamad Pauzi Zakaria, Nguyen Huu Chiem, Le Y Minh, Maricar Prudente, Ruchaya Boonyatumanond, Mahua Saha, Santosh Kumar Sarkar, Hideshige TakadaAbstract:
Abstract This paper reports the result of sewage pollution monitoring conducted in South and Southeast Asia during 1998–2003 using linear Alkylbenzenes (LABs) as molecular tracers of sewage contamination. Eighty-nine water samples collected from Malaysia, Vietnam, and Japan (Tokyo), and 161 surface sediment samples collected from Tokyo, Thailand, Malaysia, Philippines, Vietnam, Cambodia, Indonesia, and India were analyzed for Alkylbenzenes. The concentration range of ∑LABs in river water particles in Southeast Asia (
Alkylbenzenes in mussels from south and south east asian coasts as a molecular tool to assess sewage impactMarine Pollution Bulletin, 2002Co-Authors: Shinobu Tsutsumi, Yuka Yamaguchi, Itsuko Nishida, Kenichiro Akiyama, Mohamad Pauzi Zakaria, Hideshige TakadaAbstract:
Abstract Alkylbenzenes, molecular markers of sewage, were measured in 34 green mussels collected from India, Indonesia, Malaysia, Thailand, Cambodia, Vietnam, and the Philippines together with blue mussels collected from Tokyo Bay, Japan. Linear alkylbenzene (LAB) concentrations in South and South East Asian countries ranged from 10 to 1640 ng-∑LAB/g-dry tissue. In some populous cities, LAB concentrations were similar or higher than those found in northern Tokyo Bay which is heavily impacted by sewage effluents. I / E ratios (a ratio of internal to external isomers of LABs) in the South and South East Asian countries (1–3) were much lower than those in Tokyo Bay (3–8), indicating sewage discharged in the coastal zone is poorly treated (e.g., raw sewage and/or primary effluents). Alkylbenzenes with branched alkyl chains, tetrapropylene-based Alkylbenzenes, were also detected in mussels from Indonesia and Philippines. This “tell-tale” sign indicates that poorly degradable detergents are still in use in this area, although they have long been phased-out in many industrialized countries.
biodegradation experiments of linear Alkylbenzenes labs isomeric composition of c12 labs as an indicator of the degree of lab degradation in the aquatic environmentEnvironmental Science & Technology, 1990Co-Authors: Hideshige Takada, Ryoshi IshiwatariAbstract:
Realisation en laboratoire d’incubations de n-Alkylbenzenes pour mettre en evidence de facon systematique l’alteration microbienne de leurs compositions isomeres en milieu aqueux
Hideo Togo – 3rd expert on this subject based on the ideXlab platform
benzylic acetoxylation of Alkylbenzenes with phi oac 2 in the presence of catalytic amounts of tsnh2 and i2Tetrahedron Letters, 2011Co-Authors: Haruka Baba, Katsuhiko Moriyama, Hideo TogoAbstract:
Treatment of Alkylbenzenes with (diacetoxyiodo)benzene in the presence of catalytic amounts of p-toluenesulfonamide or p-nitrobenzenesulfonamide, and molecular iodine in 1,2-dichloroethane at 60 °C gave the corresponding (α-acetoxy)Alkylbenzenes in good to moderate yields. The present reaction is a simple method for the introduction of an acetoxy group to the benzylic position of Alkylbenzenes.
sulfonylamidation of Alkylbenzenes at benzylic position with p toluenesulfonamide and 1 3 diiodo 5 5 dimethylhydantoinTetrahedron Letters, 2010Co-Authors: Haruka Baba, Hideo TogoAbstract:
Abstract Treatment of Alkylbenzenes with p-toluenesulfonamide and 1,3-diiodo-5,5-dimethylhydantoin (DIH) in a small amount of carbon tetrachloride at 60 °C gave the corresponding α-p-toluenesulfonylamido)Alkylbenzenes in good to moderate yields. The present reaction is a simple method for the α-sulfonylamidation of the benzylic position in Alkylbenzenes.