The Challenge in Coal Tar Chemicals

Franck, Heinz‐Gerhard

doi:10.1021/ie50641a006

Cited by 17 publications

(9 citation statements)

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“…In most cases, they originate from natural and anthropogenic pyrolysis of organic material such as in forest fires, coal-refining processes, and the oil industry. The resulting mixtures of products often consist of an enormous number of individual substances; coal tars for example are suggested to contain more than 10000 single compounds (1).…”

Section: Introductionmentioning

confidence: 99%

Anaerobic Cometabolic Transformation of Polycyclic and Heterocyclic Aromatic Hydrocarbons: Evidence from Laboratory and Field Studies

Safinowski

Griebler

Meckenstock

2006

Environ. Sci. Technol.

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The sulfate-reducing enrichment culture N47 can grow on naphthalene or 2-methylnaphthalene as the sole carbon and energy source. Here we show that the culture can furthermore cometabolicallytransform a variety of polycyclic and heteroaromatic compounds with naphthalene or methylnaphthalene as the auxiliary substrate. Most of the cosubstrates were converted to the corresponding carboxylic acids, frequently to several isomers. The mass spectra of specific metabolites that were extracted from supernatants of cultures containing the cosubstrates benzothiophene, benzofuran, and 1-methylnaphthalene resembled known intermediates of the anaerobic naphthalene and 2-methylnaphthalene degradation pathways (i.e., naphthyl-2-methylsuccinic acid and naphthyl-2-methylenesuccinic acid). This indicates that some of the tested compounds were first methylated and then transformed to the corresponding methylsuccinic acids by a fumarate addition to the methyl group. For some of the cosubstrates, a partial or total inhibition of growth on the auxiliary substrate was observed. This was not caused by the toxicity of the individual cosubstrate itself, but by a specific combination of auxiliary substrate and cosubstrate. None of the cosubstrates tested could be utilized as the sole carbon source and electron donor by the enrichment culture N47. Field investigations at the tar-oil-contaminated aquifer, where strain N47 originated, revealed the presence of a number of metabolites similar to the ones identified in batch culture supernatants. Our findings suggest that aromatic hydrocarbons and heterocyclic compounds can be converted by aquifer organisms and produce a variety of polar compounds that become mobile in groundwater.

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Section: Introductionmentioning

confidence: 99%

Anaerobic Cometabolic Transformation of Polycyclic and Heterocyclic Aromatic Hydrocarbons: Evidence from Laboratory and Field Studies

Safinowski

Griebler

Meckenstock

2006

Environ. Sci. Technol.

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“…In fuels, there are various N-, S-, and O-containing compounds such as residuals from crude oil or additives for quality enhancement ( − ). Coal tar and creosote are more complex mixtures and are known to include a number of functionally substituted and heterocyclic aromatic compounds ( − ). Dis solution of these polar compounds from NAPL is, however, difficult to handle since experimental data on NAPL−water partitioning are very limited (), and the estimation methods above are inaccurate for polar compounds.…”

Section: Introductionmentioning

confidence: 99%

“…In contrast, the application of the PP-LFER approach to more complex mixtures, such as coal tar and creosote, has not been attempted yet. Since coal tar and creosote contain a huge number of nonpolar and polar contaminants ( , ), PP-LFER approaches, which can handle a broad range of compounds, are likely to be useful.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Partitioning between Complex Organic Mixtures and Water: Application of Polyparameter Linear Free Energy Relationships

Endo

Schmidt

2005

Environ. Sci. Technol.

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Equilibrium partitioning between nonaqueous phase liquids (NAPLs) and water is a governing process for contaminants leaching from NAPLs. Conventional prediction methods, such as Raoult's law and single-parameter linear free energy relationship (SP-LFER), are inaccurate for compounds with polar functional groups. Therefore, this study introduces a polyparameter linear free energy relationship (PP-LFER) approach as a more general tool to predict NAPL-water partitioning coefficients. Our approach was evaluated using 441 experimental partitioning data from 30 references. Experimental fuel-water partitioning coefficients were generally well reproduced by existing PP-LFERs for pure solvents using either a volume-fraction weighted sum of partitioning coefficients K (linear model, R2 = 0.983, root-mean-squared error [rmse] = 0.23) or a volume-fraction weighted sum of log K (log linear model, R2 = 0.976, rmse = 0.28). Using the linear model, estimations were, in most cases, within a factor of 2 from the experimental values, regardless of the type of compounds and the presence of a fuel additive. In contrast, the log linear model considerably underestimated partitioning coefficients in the presence of strong solute-solvent hydrogen bonding. For coal tar-water partitioning coefficients (Kcoal tar/w), new PP-LFER equations were calculated based on experimental log Kcoal tar/w values of 35 compounds. The resulting regression equation was log Kcoal tar/w = 0.40(+/-0.33) + 0.34(+/-0.32)E+ 0.61(+/-0.57)S-0.55-(+/-0.61)A-5.07(+/-0.61)B + 3.22(+/-0.35)V with the rmse equal to 0.21, where E, S, A, B, and Vare Abraham's solute descriptors. Partitioning coefficients for phenol and alcohols, calculated by the above equation, were much closer to the experimental values than to those estimated by the SP-LFER approach with octanol-water partitioning coefficients. The values of the coefficients also provide insight into the properties of coal tar in terms of molecular interactions with solutes. Consequently, using the approaches presented in this study, complex organic mixture-water partitioning coefficients of a wide range of organic compounds with varying polarity can be reasonably estimated.

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“…2 Commercial Cz was produced from coal tar, which contains an estimated 10 000 chemical compounds. 12 In principle, many raw materials from coal tar were accompanied by unknown impurities, as most commercial compounds are offered with a purity of 95−98%. Intriguingly, in 1947, a review of Cz already mentioned that commercial Cz gave a yellow solution in concentrated sulfuric acid, but the solution for lab-prepared Cz was colorless, indicating that commercial Cz may contain unknown impurities.…”

mentioning

confidence: 99%

“…Commercial Cz was produced from coal tar, which contains an estimated 10 000 chemical compounds . In principle, many raw materials from coal tar were accompanied by unknown impurities, as most commercial compounds are offered with a purity of 95–98%.…”

mentioning

confidence: 99%

Revisiting Carbazole: Origin, Impurity, and Properties

Chen

Chong

Pan

et al. 2021

ACS Materials Lett.

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Photoluminescence quantum yield (PLQY) is one of the most important characteristics for organic luminescent materials. However, when carbazole prepared from the lab was compared to that from a commercial source, a remarkable change of PLQY was observed to vary from 37.1% to 69.8%. Taking 9-(4-bromobenzyl)-9H-carbazole (CzBBr) as an example of carbazole derivatives, the PLQYs of CzBBr synthesized from different origins of carbazole were varied from 16.0% to 91.1%. Our studies demonstrated that efficient radiative transition pathways were activated for commercial carbazole based luminescence, leading to a large enhancement in PLQY with fluorescence (from 16.0% to 54.4%) and phosphorescence (from <1% to 36.7%) for CzBBr. These results suggest that the origin of carbazole plays a very important role in determining the optical properties of carbazole derivatives, alerting us to carefully revisit carbazole and its derivatives, especially those with record-high efficiency.

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The Challenge in Coal Tar Chemicals

Cited by 17 publications

References 0 publications

Anaerobic Cometabolic Transformation of Polycyclic and Heterocyclic Aromatic Hydrocarbons: Evidence from Laboratory and Field Studies

Anaerobic Cometabolic Transformation of Polycyclic and Heterocyclic Aromatic Hydrocarbons: Evidence from Laboratory and Field Studies

Prediction of Partitioning between Complex Organic Mixtures and Water: Application of Polyparameter Linear Free Energy Relationships

Revisiting Carbazole: Origin, Impurity, and Properties

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