Fate of low molecular weight organic substances in an arable soil: From microbial uptake to utilisation and stabilisation

PRODUCTION OF ROAD OIL BITUMENS BY THE METHOD OF CHEMICAL MODIFICATION OF OIL RESIDUES © V.М. Gunka, PhD in technical sciences, Yu.V. Prysiazhnyi, PhD in technical sciences, Yu.Ya. Demchuk, PhD in technical sciences, Yu.M. Hrynchuk, PhD in technical sciences, Yu.V. Sidun, PhD in technical sciences, M.M. Bratychak, Doctor of Chemical Sciences (Lviv Polytechnic Naional University, 12 Stepan Bandera Str., 79013, Lviv, Ukraine) The article is devoted to obtaining road oil bitumen from oil residues by modifying them with relatively cheap low molecular weight organic substances. The proposed method relates to a chemical modification, which, in case of its industrial implementation, will allow avoiding the use of expensive physical modifiers. A 37 % aqueous solution of formaldehyde was used as low molecular weight organic substances (modifier / chemical reagent of the process) for chemical modification of tar; concentrated sulfuric acid (H2SO4) was used as a catalyst for the chemical modification of tar. As a feedstock for chemical modification, we used an oil residue - tar, selected at PJSC “Ukrtatnafta” (Kremenchug, Ukraine). The chemical modification with formaldehyde was carried out in hermetic stationary containers capable of operating under excess pressure. The photographs of the equipment are given. Since the ultimate goal of the work was to obtain road oil bitumen, then, analyzing the results of experimental studies, we focused on the quality characteristics of this particular product. At the same time, the most important quality indicators were determined, namely: the depth of needle penetration, softening temperature, ductility (extensibility), adhesion to glass (adhesion to glass), Fraas brittle temperature, penetration index. For tar, the following characteristics such as density, flash point in an open crucible, and a boiling point were additionally determined. As a result of the experiments, the fundamental possibility of obtaining road oil bitumen by the method of chemical modification of tar with formaldehyde was established. It was revealed that the process factors (formaldehyde content in the reaction mixture, catalyst content in the reaction mixture, temperature and duration) have a significant effect on the quality of the resulting product. Changing their values allows you to adjust the values of the quality characteristics of the resulting bitumen. Keywords: binders, bitumen, oil residue, modification. Corresponding author V.М. Gunka, e-mail: [email protected]

Download Full-text

Fingerprinting of volatile organic compounds for quick assessment of vigour status of seeds

Seed Science Research ◽

10.1017/s0960258520000252 ◽

2020 ◽

Vol 30 (2) ◽

pp. 112-121 ◽

Cited By ~ 1

Author(s):

R. Umarani ◽

M. Bhaskaran ◽

C. Vanitha ◽

M. Tilak

Keyword(s):

Molecular Weight ◽

Volatile Organic Compounds ◽

Moisture Content ◽

Organic Compounds ◽

Low Molecular Weight ◽

Organic Substances ◽

Seed Deterioration ◽

Volatile Organic ◽

Quick Assessment ◽

Storage Reserves

AbstractSeed is a fertilized mature ovule, which possesses an embryonic plant. When the dry, mature seeds are subjected to imbibition, they release a wide range of organic substances, which include low molecular weight carbonyl compounds (gases and volatiles) and water-soluble organic substances (enzymes and polysaccharides). The volatile organic compounds (VOCs) are molecules of low molecular weight (300 g mol−1) and high vapour pressure (0.01 kPa at 20°C) and include diverse chemical compounds. The nature and emission kinetics of volatiles produced from seeds vary, depending on the moisture content of the seeds. Orthodox seeds stored at ‘low seed moisture content’ undergo seed deterioration, predominantly due to lipid peroxidation, initiated by autoxidation or enzymatic oxidation of unsaturated or polyunsaturated fatty acids. This peroxidation leads to emission of volatile compounds. The quantity of VOCs emitted is positively correlated with the advancement of seed deterioration. With respect to the seed germination process, exposure of seeds to ‘high moisture conditions’ leads to increased respiration, triggers glycolysis and mobilization of storage reserves, resulting in the emission of volatile metabolic products. The quantity of VOCs emitted on commencement of metabolic activity in germinating seeds depends on (1) vigour status and (2) amount of storage reserves. Since it has been established that there is a significant difference between high and low vigour seeds with respect to quantity and profile of VOCs emitted, there is great potential for utilizing the VOC profile to obtain a quick and reproducible test of vigour status of crop seeds. In order to harness the VOC profile for quick assessment of vigour status of seeds, research has to be taken up to develop standard protocols for fingerprinting of VOCs for the purpose of seed vigour assessment and to fix the standard volatile biomarker(s) specific to crop and vigour status of seeds.

Download Full-text

Structural Investigations: Occurrence of Amino Acids, Carbohydrates, and Low-Molecular-weight Organic Acids in Refractory Organic Substances

Refractory Organic Substances in the Environment ◽

10.1002/9783527611195.ch2o ◽

2007 ◽

pp. 264-281 ◽

Cited By ~ 1

Author(s):

J. B. Jahnel ◽

T. Brinkmann ◽

G. Abbt-Braun ◽

F. H. Frimmel

Keyword(s):

Amino Acids ◽

Molecular Weight ◽

Organic Acids ◽

Low Molecular Weight ◽

Organic Substances ◽

Structural Investigations

Download Full-text

Weaker priming and mineralisation of low molecular weight organic substances in paddy than in upland soil

European Journal of Soil Biology ◽

10.1016/j.ejsobi.2017.09.008 ◽

2017 ◽

Vol 83 ◽

pp. 9-17 ◽

Cited By ~ 12

Author(s):

Husen Qiu ◽

Xiaodong Zheng ◽

Tida Ge ◽

Maxim Dorodnikov ◽

Xiangbi Chen ◽

...

Keyword(s):

Molecular Weight ◽

Low Molecular Weight ◽

Organic Substances ◽

Upland Soil

Download Full-text

NITROGEN MINERALIZATION IN A SIMULATED RHIZOSPHERE AS INFLUENCED BY LOW MOLECULAR WEIGHT ORGANIC SUBSTANCES

Acta Horticulturae ◽

10.17660/actahortic.2012.958.10 ◽

2012 ◽

pp. 99-104 ◽

Cited By ~ 1

Author(s):

S.A. Begum ◽

M.A. Kader ◽

S. Sleutel ◽

S. De Neve

Keyword(s):

Molecular Weight ◽

Nitrogen Mineralization ◽

Low Molecular Weight ◽

Organic Substances

Download Full-text

A high-performance oil-free backing pump for electron microscopes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100107691 ◽

1978 ◽

Vol 36 (1) ◽

pp. 110-111

Author(s):

G.K.W. Balkau ◽

E. Bez ◽

J.L. Farrant

Keyword(s):

Molecular Weight ◽

Electron Microscope ◽

Hot Spots ◽

High Performance ◽

Carbonaceous Material ◽

Contamination Rate ◽

Low Molecular Weight ◽

Principal Source ◽

Rotary Pumps ◽

Electron Microscopes

The earliest account of the contamination of electron microscope specimens by the deposition of carbonaceous material during electron irradiation was published in 1947 by Watson who was then working in Canada. It was soon established that this carbonaceous material is formed from organic vapours, and it is now recognized that the principal source is the oil-sealed rotary pumps which provide the backing vacuum. It has been shown that the organic vapours consist of low molecular weight fragments of oil molecules which have been degraded at hot spots produced by friction between the vanes and the surfaces on which they slide. As satisfactory oil-free pumps are unavailable, it is standard electron microscope practice to reduce the partial pressure of organic vapours in the microscope in the vicinity of the specimen by using liquid-nitrogen cooled anti-contamination devices. Traps of this type are sufficient to reduce the contamination rate to about 0.1 Å per min, which is tolerable for many investigations.

Download Full-text