Analysis of Volatile Components of Jasmine and Jasmine Tea during Scenting Process

Jasmine tea is widely loved by the public because of its unique and pleasant aroma and taste. The new scenting process is different from the traditional scenting process, because the new scenting process has a thin pile height to reduce the high temperature and prolong the scenting time. We qualified and quantified volatiles in jasmine and jasmine tea during the scenting process by gas chromatography-mass spectrometry (GC-MS) with a headspace solid-phase microextraction (HS-SPME). There were 71 and 78 effective volatiles in jasmine and jasmine tea, respectively, including 24 terpenes, 9 alcohols, 24 esters, 6 hydrocarbons, 1 ketone, 3 aldehydes, 2 nitrogen compounds, and 2 oxygen-containing compounds in jasmine; 29 terpenes, 6 alcohols, 28 esters, 8 nitrogen compounds, 1 aldehyde, and 6 other compounds in jasmine tea. The amounts of terpenes, esters, alcohols, nitrogen compounds, and hydrocarbons in jasmine and tea rose and then fell. The amount of oxygenated compounds of tea in the new scenting process first rose and then fell, while it showed a continuous upward trend during the traditional process. The amount of volatiles in jasmine and tea produced by the new scenting process were higher than that of the traditional scenting process at the same time. This study indicated that jasmine tea produced by the new scenting process had better volatile quality, which can provide proof for the new scenting process.

Humus substances in the swamp ecosystems of taiga zone of Western Siberia

Eutrophic peatlands with a predominantly humate type of humus is dominated according to content of hydrophobic humus substances accumulated in the solid phase of peat. Oligotrophic peatlands with fulvate type of humus are characterized by minimal storages. Mesotrophic peatlands occupy a transitional position, both in terms of storage and in terms of the humus type – humate-fulvate. Hydrophilic components of the water phase are characterized by fulvate humus, regardless of the type of peatland, but differ in the proportion of the contribution of humus substances in the amphiphilic system of swamp ecosystems. It is the highest in the thickness of the oligotrophic peatland almost 31%, slightly lower in the mesotrophic – 25% and much less in the eutrophic – 6%. Structural features of macromolecules of humic acids of swamp waters of various genesis are determined. The humic acids of mesotrophic waters are adjacent to the group of reduced compounds, they are more enriched with aromatic structures and carboxyl groups in relation to oligotrophic waters. The humic acids of oligotrophic waters belong to a group of oxygenated compounds, have low enrichment of nitrogen, contain more methoxyl carbon and carbohydrates (polysaccharides). These structural features are caused by geochemistry of waters feeding the peatlands and specific mechanisms of humic acids synthesis on the swamps of different genesis. The volume of dissolved organic carbon stock from wetland ecosystems through system of taiga rivers of left bank of Middle Ob is 805 kt per year.

Co-Pyrolysis of Neem Wood Bark and Low-Density Polyethylene: Lnfluence of Plastic on Pyrolysis Product Distribution and Bio-Oil Characterization

In this study, the investigation on effect of plastic during co-pyrolysis with biomass has been carried out in a fixed reactor. Pyrolysis of neem wood bark (NB), low density polyethylene (LDPE) and their blends at different ratios is performed in order to evaluate the product distribution. The effects of reaction temperature, NB-to-LDPE blend ratio on product distribution and chemical compositions of bio-oil are examined. The co-pyrolysis of NB and LDPE increased the yield and quality of the bio-oil. The experiments are conducted under different LDPE addition percentage such as 20%, 40%, 50%, 60% and 80%. Under the optimum experimental condition of 60% addition of LDPE and temperature of 450°C, the maximum yield of bio-oil (64.8 wt%) and hydrocarbon (75.2%) are achieved with the lowest yield of oxygenated compounds. The calorific value of the co-pyrolytic oil is found to be higher than that of NB pyrolytic oil. The relation between NB and LDPE during co-pyrolysis has been validated by GC–MS analysis, which shows in decrease of oxygenated compounds.

EFFECT OF OXYGENATED COMPOUNDS ON 1,3-BUTADIENE POLYMERIZATIONS PERFORMED WITH NEODYMIUM VERSATATE. PART I: ALCOHOLS, ALDEHYDES, KETONES, AND WATER

ABSTRACT 1,3-butadiene (1,3-BD) is a building block produced mainly as a byproduct of the ethylene steam cracking process. However, due to the growing interest in sustainable technologies, there is also growing interest in manufacturing 1,3-BD from ethanol. For this reason, taking into account that the ethanol-derived 1,3-BD can contain oxygenated contaminants that are difficult to remove, the present manuscript investigates for the first time how the presence of low concentrations of some oxygenates (acetaldehyde, crotonaldehyde, 3-hydroxybutyraldehyde, acetone, water, ethanol, 1,3-butanodiol, 3-buten2-ol, crotyl alcohol, and 1-butanol) in the 1,3-BD monomer can affect polymerization reactions performed with the neodymium versatate catalyst and modify the characteristics of the obtained polybutadiene products. It is shown that the presence of oxygenated compounds can cause inhibitory effects on the course of the polymerization and modify the molar mass distributions and flow properties of the final products, although all analyzed samples presented the characteristic high-cis character of polybutadienes produced with the neodymium versatate catalyst.

Hydrodeoxygenation of Xylose Isopropylidene Ketal Over Pd/HBEA Catalyst for the Production of Green Fuels

1,2:3,5-Di-O-isopropylidene-α-D-xylofuranose (DX) is a major component of a new bio-crude: a viscous oil presenting petroleum-friendly properties produced by the ketalization of sugarcane bagasse. This article studies DX HDO (hydrodeoxygenation) over a Pd/HBEA catalyst in a batch reactor at 250°C. The effects of hydrogen pressure from 10 to 40 bar, catalyst/DX ratio from ½ to 2, and reaction time 0–24 h were investigated. A range of conditions for complete hydrodeoxygenated DX into alkanes with a Pd/HBEA catalyst was found. In these conditions, a low coke yield with water as the principal deoxygenated product was obtained. Further, higher amounts of alkanes containing seven or more carbons (A7+) were favored at 30 bar of hydrogen pressure, Cat/DX ratio = 2, and short reaction time. Products analysis that accompanied the above variations during reaction time led to general insights into reaction pathways. First, in the presence of DX, an effective n-hexane conversion was not observed on experiments of low catalyst/DX ratio (½) or in the initial period of high Cat/DX ratio, suggesting DX is much more successful than n-hexane to compete for active sites. Then, the formation of a pool of oxygenated compounds, such as furans, ketones, and carboxylic acids, along with lighter and heavier alkanes was observed. Hence, the aforementioned oxygenates may undergo reactions, such as aldol condensation with subsequent hydrodeoxygenation reaction, generating heavier alkanes.

On-line solid phase microextraction derivatization for the sensitive determination of multi-oxygenated volatile compounds in air

Multi-oxygenated volatile organic compounds are important markers of air pollution and precursors of ozone and secondary aerosols in both polluted and remote environments. Herein, their accurate determination was enhanced. The approach was based on an automated system for active sampling and on-fibre derivatization coupled with the gas chromatography–mass spectrometry (GC–MS) technique. The method capability was determined for different compound families, such as aldehydes, ketones, α-dicarbonyls, hydroxy-aldehydes, hydroxy-ketones, and carboxylic acids. A good accuracy (<7 %) was demonstrated from the results compared to Fourier-transform infrared spectroscopy (FTIR). Limits of detection (LODs) of 6–100 pptV were achieved with a time resolution lower than 20 min. The developed method was successfully applied to the determination of multi-oxygenated compounds in air samples collected during an intercomparison campaign (EUROCHAMP-2020 project). Also, its capability and accuracy for atmospheric monitoring was demonstrated in an isoprene ozonolysis experiment. Both were carried out in the high-volume outdoor atmospheric simulation chambers (EUPHORE, 200 m3). In summary, our developed technique offers near-real-time monitoring with direct sampling, which is an advantage in terms of handling and labour time for a proper quantification of trace levels of atmospheric multi-oxygenated compounds.