Day: November 22, 2022

Volatile profiles of Allium tenuissimum L. flower fried by four different oils, using SPME-GC-MS, and sensory evaluation coupled with partial least squares regression was written by Zhang, Chenping;Wang, Yutong;Ding, Danyang;Su, Jin;Zhao, Zhigang. And the article was included in Journal of Food Composition and Analysis in 2022.Related Products of 638-02-8 The following contents are mentioned in the article:

Allium tenuissimum L. flower is a kind of spice widely used in Northwest China, which is more fragrant after being fried. In order to assess the volatile compounds of fried Allium tenuissimum flower, solid-phase microextraction with gas chromatog.-mass spectrometry (SPME-GC-MS) and gas chromatog.-olfactometry (GC-O) were used to analyze the flower of Allium tenuissimum L. fried in four kinds of oil (rapeseed oil, peanut oil, soybean oil, and sunflower oil). A total of 50 volatiles were identified, including eight sulfur-containing compounds, ten nitrogen-containing heterocyclics, seven oxygen-containing heterocycles, eleven aldehydes, six acids and eight other compounds Sensory evaluation revealed highest scores in onion, caramel, grassy, fatty and roasty attributes. Pos. correlations between sensory attributes and aroma-active compounds were elaborated by partial least squares regression (PLSR) anal. PLSR indicated that the sensory attribute of ‘roasted’ was pos. associated with methylpyrazine, 2,5-dimethylpyrazine, and 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one. The sensory attribute of ‘onion’ was significant pos. associated with di-Me disulfide and di-Me trisulfide. 2-Pentylfuran, furfural, and 2-furanmethanol had a significant pos. impact on ‘caramel’ attribute. (E)-2-Heptenal and (E,E)-2,4-heptadienal were pos. related to ‘grassy’ attribute. ‘Fatty’ attribute was significantly pos. correlated with (E,E)-2,4-nonadienal, (E,E)-2,4-decadienal, and heptanoic acid. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Related Products of 638-02-8).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene scaffolds are of great importance due to its increased presence in bioactive molecules. It is also used in the manufacturing of dyes such as thioindigo.Related Products of 638-02-8

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Effect of sulfide group on the network structure and thermal behavior of sulfur-containing polybenzoxazines: Examining by using Py-GC-MS and TGA-FTIR was written by Ya, Lyu;Qiu, Liliang. And the article was included in Polymer Degradation and Stability in 2022.Application of 638-02-8 The following contents are mentioned in the article:

In the present paper, two sulfur-containing benzoxazine monomers were synthesized using 2-thiophenemethylamine as an amine source. The polymerization behaviors of the two monomers were compared with those of aniline and furfurylamine using differential scanning calorimetry (DSC), which revealed that the polymerization temperatures of the synthesized monomers were between those of aniline and furfurylamine. Thermogravimetric anal. (TGA) confirmed that the polybenzoxazines formed from the synthesized monomers had outstanding thermal stability. Pyrolysis-gas chromatog.-mass spectrometry (Py-GC-MS) and TGA-Fourier-transform IR spectroscopy (TGA-FTIR) were used to monitor the decomposition processes of the polymers. They allowed us to analyze the crosslinked structures of the polybenzoxazines and revealed the probable cause of their thermal stability. We found that the reliability of the thioether bonds and the di-substituted structures formed in the polybenzoxazines based on furfurylamine and thiophenemethylamine ensured the stability of the crosslinked structures. The methyl-substituted ring structures exposed by fracture react with the ammonia released at higher temperatures to form CN groups. Therefore, nitrogen is retained in the crosslinked structures and the thermal stability of the polymers is improved. Compared with common halogen- or phosphorus-containing flame-retardant polymers, the newly developed sulfur-containing polybenzoxazines are more environmentally friendly flame-retardant polymers. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Application of 638-02-8).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene is a fused ring compound of thiophene ring and benzene ring, which is an important class of heterocycles with advantageous structures. Due to its aromaticity, thiophenes do not exhibit the same properties as conventional thioethers.Application of 638-02-8

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Fractionation of Lignin with Decreased Heterogeneity: Based on a Detailed Characteristics Study of Sequentially Extracted Softwood Kraft Lignin was written by Liu, Rui;Smeds, Annika;Wang, Luyao;Pranovich, Andrey;Hemming, Jarl;Willfor, Stefan;Zhang, Hongbo;Xu, Chunlin. And the article was included in ACS Sustainable Chemistry & Engineering in 2021.Synthetic Route of C6H8S The following contents are mentioned in the article:

Industrial lignin fractionation is attracting increasing interest due to its enormous potential in the development of high value-added materials. However, the widely reported fractionation approaches are primarily focused on the separation of fractions with a low polydispersity index (PDI). In this study, based on the detailed characteristic examination of carefully sequential-extracted softwood Kraft lignin fractions, a novel method to isolate lignin fraction with decreased heterogeneity (LGF-dh), was established in consideration of impurities, elemental composition, molar mass distribution, carbohydrate content, functional hydroxyl content, and the content of lignin-relevant aromatic units. To characterize the mentioned properties, an elemental analyzer, SEC-MALS, GC-MS, GC-FID, Py/GC-MS, ³¹P-NMR, and HSQC-NMR were used to compare the differences of the sequential lignin fractions that were obtained by Me tert-Bu ether (MTBE), Et acetate (EtOAc), ethanol (EtOH), methanol (MeOH), acetone, and dioxane. Moreover, a practical and feasible three-step extraction process was proposed to sep. the low heterogeneity lignin fraction from industrial lignin according to the different solubilities of each fraction in the green cosolvent system of EtOH/water, MeOH/water, and acetone/water. Overall, this work presented a comprehensive study on the properties of softwood lignin as well as proposed a feasible and convenient method to reduce the heterogeneity of lignin, which would promote its valorization. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Synthetic Route of C6H8S).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene is relatively a stable molecule. The electrophilic substitution of benzothiophene systems is much less regioselective than that of indoles. Due to its aromaticity, thiophenes do not exhibit the same properties as conventional thioethers.Synthetic Route of C6H8S

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Pervaporative removal of organosulfur compounds (OSCs) from gasoline using PEBA and PDMS based commercial hydrophobic membranes was written by Rychlewska, Katarzyna;Kujawski, Wojciech;Konieczny, Krystyna. And the article was included in Chemical Engineering Journal (Amsterdam, Netherlands) in 2017.Recommanded Product: 638-02-8 The following contents are mentioned in the article:

Vacuum pervaporation experiments were conducted to recognize the efficiency of organosulfur compounds (OSCs) separation from gasoline using com. hydrophobic membranes. Three of typically presented in gasoline sulfur species, i.e. thiophene, 2-methylthiophene and 2,5-dimethylthiophene, were selected to investigate the different sulfur compounds removal efficiency from n-octane/sulfur species used as a model gasoline. The influence of process parameters such as feed temperature, feed concentration on OSCs removal from model n-octane/sulfur compound mixtures was also examined During the test, the com. hydrophobic PEBA-based and PDMS-based composite membranes were applied. Conducted experiments with chosen sulfur species confirmed that the structure of a component and the resulting differences in the affinity toward tested membrane and physico-chem. properties can influence the membrane performance and led to different separation efficiency. Total fluxes for n-octane/thiophene, n-octane/2-methylthiophene and octane/2,5-dimethylthiophene mixtures at 30 °C were equal to be 1.33, 1.42 and 1.29 kg/m² h in case of PEBA membrane and 7.21, 7.48 and 7.34 kg/m² h for PDMS-base membrane, with the corresponding separation factor β values of 7.04, 3.95 and 1.25 for PEBA and 2.95, 1.56 and 1.01 for PDMS, resp. The intrinsic selectivity for thiophene/n-octane mixture (α_T/O) also indicated that PEBA membrane (α_T/O ≈ 18) is much more selective than PDMS one (α_T/O ≈ 7.5). This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Recommanded Product: 638-02-8).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Functionalized benzothiophenes are important constructs found in molecules with wide ranging biological activity and in organic materials. It is found within the chemical structures of pharmaceutical drugs such as raloxifene, zileuton, and sertaconazole, and also BTCP.Recommanded Product: 638-02-8

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

The Effects of Antioxidants on the Changes in Volatile Compounds in Heated Welsh Onions (Allium fistulosum L.) during Storage was written by Lee, Sang Mi;Kim, Dami;Kim, Young-Suk. And the article was included in Molecules in 2022.COA of Formula: C6H8S The following contents are mentioned in the article:

Welsh onion (Allium fistulosum L.) is usually used to enhance the flavor characteristics of various foods. Volatile compounds in Welsh onions, including sulfur-containing compounds, may vary during heat process and storage. Accordingly, the changes in the volatile compounds in Welsh onions, subjected to heat and antioxidant (ascorbic acid and glutathione) treatments during storage, are investigated in the present study. The majority of sulfur-containing compounds in Welsh onions showed significant differences between the untreated Welsh onions and heated Welsh onions. During the heating of the Welsh onions, some sulfur-containing compounds, such as 2-methylthiirane, 1-(methyldisulfanyl)prop-1-ene, 1-[[(E)-prop-1-enyl]disulfanyl]propane, 1-(propyltrisulfanyl)propane, 1-[[(E)-prop-1-enyl]trisulfanyl]propane, and (methyltetrasulfanyl)methane, showed significant differences between the untreated and heated Welsh onions (p < 0.05). In addition, partial least square discriminant anal. (PLS-DA) was applied to discriminate the heated Welsh onion samples added with different antioxidants. The heated Welsh onion samples added with ascorbic acid was mainly associated with 2-phenylacetaldehyde, acetic acid, methylsulfanylmethane, prop-2-ene-1-thiol, undecan-2-one, and (2E,4E)-deca-2,4-dienal. Moreover, the key volatile compounds in the heated Welsh onion samples added with glutathione were 3-ethylthiophene, 1-(methyldisulfanyl)-1-methylsulfanylpropane, 1-methylsulfanylpentane, 2-prop-2-enylsulfanylpropane, and 1-propan-2-ylsulfanylbutane. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8COA of Formula: C6H8S).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Functionalized benzothiophenes are important constructs found in molecules with wide ranging biological activity and in organic materials. The different substitution patterns in these heterocycles offer new opportunities for drug discovery and other applications in materials science.COA of Formula: C6H8S

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Quantitative analysis of Toona sinensis aroma components and variation rule during hot air dry process was written by Guo, Wei-yun;Li, Guang-hui;Zhang, Zhen-zhen;Lu, Fang;Yu, Xiao-na. And the article was included in Shipin Yanjiu Yu Kaifa in 2021.SDS of cas: 638-02-8 The following contents are mentioned in the article:

The aim of the study was to establish the quant. method for Toona sinensis aroma components and explore its changes during processing. The organic solvent extraction and gas chromatog.-mass spectrometry (GC-MS) was used to anal. the characteristic aroma components of Toona sinensis and the change rules of three characteristic aroma components at the hot air drying temperatures Results showed that the order of the extraction effect of the four extractants was acetonitrile, Et acetate, ethanol and n-hexane, and the order of the purification effect of the three purification agents was pesticarb (PC), octadecylsilyl (ODS) and primary secondary amine (PSA). The best extraction agent for the pretreatment of Toona sinensis was acetonitrile, and the best purification agent was PC. The contents of 3, 4-dimethylthiophene, inverse 2-hexenal and 2, 5-dimethylthiophene decreased in general, but the trend and amplitude were not the same. The content of 3, 4-dimethylthiophene decreased by 15.08% during 4 h drying. The content of 2, 5-dimethylthiophene varied greatly, reaching 89.75%. It could be seen that there were precursors in Toona sinensis from the change trend of the three target substances. The thermal effect would promote the decomposition and transformation of these precursors to the target substances, but the extension of drying time would promote the continuous loss of the target materials. The sensory evaluation test showed that the sensory quality of Toona sinensis was better when the hot air drying temperature was 50°C and the hot air drying time was 2 h. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8SDS of cas: 638-02-8).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene is used as starting material for the synthesis of bioactive molecules. The core structure is a part of various pharmaceutical substances and natural products. The different substitution patterns in these heterocycles offer new opportunities for drug discovery and other applications in materials science.SDS of cas: 638-02-8

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Applications of thermal desorption coupled to comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry for hydrocarbon fingerprinting of hydraulically fractured shale rocks was written by Piotrowski, Paulina K.;Tasker, Travis L.;Burgos, William D.;Dorman, Frank L.. And the article was included in Journal of Chromatography A in 2018.SDS of cas: 638-02-8 The following contents are mentioned in the article:

Development of shale gas resources through the use of hydraulic fracturing has raised a multitude of environmental concerns and motivated research towards the understanding of shale gas systems. Previous research has demonstrated the potential of utilizing hydrocarbon distributions towards the fingerprinting of a potential environmental contamination event arising from shale gas operations. However, to apply hydrocarbon distributions from shale gas wells towards point-source identification and apportionment, a better understanding of hydrocarbon origins must be achieved. Here we present an efficient and repeatable thermal desorption method, as a sample introduction methodol. for GC × GC anal. of shale rock samples that results in comparable chromatograms to those produced by solvent extraction This novel and robust characterization technique of shale cores from Marcellus and Utica formations by thermal desorption followed by GC × GC enables the understanding of hydrocarbon speciation within the native rock with minimal sample preparation time and solvent use. The detailed shale chem. gives insight into utilizing hydrocarbon differences towards point-source identification methodologies of environmental contamination events associated with unconventional gas development. Addnl., this anal. technique may provide a more detailed anal. of hydrocarbons than what is currently implemented in the industry to pinpoint the most advantageous areas to exploit by hydraulic fracturing, yet avoiding undesirable areas such as those with a high abundance of sulfur containing compounds This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8SDS of cas: 638-02-8).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene finds use in research as a starting material for the synthesis of larger, usually bioactive structures. Due to its aromaticity, thiophenes do not exhibit the same properties as conventional thioethers.SDS of cas: 638-02-8

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Benchmarking the minimum Electron Beam (eBeam) dose required for the sterilization of space foods was written by Bhatia, Sohini S.;Wall, Kayley R.;Kerth, Chris R.;Pillai, Suresh D.. And the article was included in Radiation Physics and Chemistry in 2018.Reference of 638-02-8 The following contents are mentioned in the article:

As manned space missions extend in length, the safety, nutrition, acceptability, and shelf life of space foods are of paramount importance to NASA. Since food and mealtimes play a key role in reducing stress and boredom of prolonged missions, the quality of food in terms of appearance, flavor, texture, and aroma can have significant psychol. ramifications on astronaut performance. The FDA, which oversees space foods, currently requires a min. dose of 44 kGy for irradiated space foods. The underlying hypothesis was that com. sterility of space foods could be achieved at a significantly lower dose, and this lowered dose would pos. affect the shelf life of the product. Electron beam processed beef fajitas were used as an example NASA space food to benchmark the min. eBeam dose required for sterility. A 15 kGy dose was able to achieve an approx. 10 log reduction in Shiga-toxin-producing Escherichia coli bacteria, and a 5 log reduction in Clostridium sporogenes spores. Furthermore, accelerated shelf life testing (ASLT) to determine sensory and quality characteristics under various conditions was conducted. Using Multidimensional gas-chromatog.-olfactometry-mass spectrometry (MDGC-O-MS), numerous volatiles were shown to be dependent on the dose applied to the product. Furthermore, concentrations of off -flavor aroma compounds such as di-Me sulfide were decreased at the reduced 15 kGy dose. The results suggest that the combination of conventional cooking combined with eBeam processing (15 kGy) can achieve the safety and shelf-life objectives needed for long duration space-foods. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Reference of 638-02-8).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophenes are valuable heterocycles that are widely used in medicines, agrochemicals, and materials science. It has been used as a raw material for the synthesis of biologically active structures and is found in pharmaceuticals such as leukotriene synthesis inhibitors and antifungals, as well as in many natural products.Reference of 638-02-8

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Analysis of pollutants in the product gas of a pilot scale downdraft gasifier fed with wood, or mixtures of wood and waste materials was written by Vonk, G.;Piriou, B.;Wolbert, D.;Cammarano, C.;Vaitilingom, G.. And the article was included in Biomass and Bioenergy in 2019.Category: benzothiophene The following contents are mentioned in the article:

Small scale gasification of Solid Recovered Fuels (SRF) in downdraft reactors could be an alternative to large scale waste-to-energy schemes. In this perspective, the assessment of the pollutant emissions at pilot scale is necessary. This work compares pollutant emissions from wood and SRF air gasification in a downdraft fixed bed gasifier. Five fuels have been studied: Poplar wood, SRF wood, and three different mixtures containing mass fractions of 80% SRF wood with 20% of either tire, plastic waste or sewage sludge. Air gasification was performed in a pilot scale reactor in fed-batch mode using a fuel mass ranging from 5 to 8 kg and an air inlet flow of 170-180 L min^-1 (at 0°C and 101 325 Pa). Depending on the fuel, Equivalence Ratios (ER) ranged from 0.22 to 0.29 and gasification temperatures from 690 to 850°C. Emissions analyses were performed on product gas, condensable species and remaining chars, with a particular focus on sulfur, nitrogen and heavy metals. Regarding sulfur, wood and SRF wood led to low H₂S contents (6-8μmol mol^-1), when SRF mixes led to higher concentrations (44-96μmol mol^-1) in addition to of up to 11 heavier sulfur compounds Regarding nitrogen, SRF produced higher ammonia concentrations (2.1-7.6 mmol mol^-1) than Wood (619μmol mol^-1), as a result of initial nitrogen mass fractions17 to 27 times higher in the SRF mixes. Heavy metals analyzed in remaining solids after gasification showed low recovery rates (<0.4%), and tend to accumulate in fine particles, as a result of their volatility. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8Category: benzothiophene).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene is relatively a stable molecule. The core structure is a part of various pharmaceutical substances and natural products. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization.Category: benzothiophene

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem

Comprehensive Three-Dimensional Gas Chromatography with Time-of-Flight Mass Spectrometry was written by Watson, Nathanial E.;Bahaghighat, H. Daniel;Cui, Ke;Synovec, Robert E.. And the article was included in Analytical Chemistry (Washington, DC, United States) in 2017.COA of Formula: C6H8S The following contents are mentioned in the article:

Development of comprehensive, three-dimensional (3D) gas chromatog. with time-of-flight mass spectrometric detection (GC³/TOFMS) is described. This instrument provides four dimensions (4D) of chem. selectivity and includes significant improvements to total selectivity (mass spectrometric and chromatog.), peak identification, and operational temperature range relative to previous models of the GC³ reported. The new instrumental design and data output are evaluated and illustrated via two samples, a 115-component test mixture and a diesel fuel spiked with several compounds, for the purpose of illustrating the chem. selectivity benefits of this instrumental platform. Useful approaches to visualize the 4-dimensional data are presented. The GC³/TOFMS instrument exptl. achieved total peak capacity, n_c,3D, ranging from 5000 to 9600 (x̅ = 7000, s = 1700) for 10 representative analytes for 50 min separations with component dimensional peak capacities averaging 406, 3.6, and 4.9 for ¹D, ²D, and ³D, resp. Particularly, GC³/TOFMS achieved a combined ²D × ³D peak capacity ranging from 10 to 26 (x̅ = 17.6, s = 5.0), which is similar to what is achieved by ²D alone in a GC × GC operating at equivalent modulation period conditions. The anal. benefits of employing three varied chem. selectivities in the 3-dimensional separation coupled with TOFMS are illustrated through the separation and detection of 1,6-dichlorohexane and cyclohexyl isothiocyanate as part of the diesel fuel anal. This study involved multiple reactions and reactants, such as 2,5-Dimethylthiophene (cas: 638-02-8COA of Formula: C6H8S).

2,5-Dimethylthiophene (cas: 638-02-8) belongs to benzothiophene derivatives. Benzothiophene scaffolds are of great importance due to its increased presence in bioactive molecules. Its aromaticity makes it relatively stable, although as a heterocycle, it has reactive sites which allow for functionalization.COA of Formula: C6H8S

Referemce:
Benzothiophene – Wikipedia,
Benzothiophene | C8H6S – PubChem