scholarly journals Determination of polymeric functional additives in diesel fuel by gel penetration chromatography

2021 ◽  
Vol 25 (1) ◽  
pp. 53-62
Author(s):  
Yu. A. Ivanova ◽  
◽  
Z. A. Temerdashev ◽  
I. A. Kolychev ◽  
N. V. Kiseleva ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Diesel Fuel ◽  
Solid Phase ◽  
Chromatographic System ◽  
Molecular Weights ◽  
Functional Additives ◽  
Molecular Weight Characteristics ◽  
Wide Range ◽  
Dispersant Additive

Current article is devoted to the development of a method for determining polymer functional additives and their molecular weight characteristics in diesel fuel by gel penetration chromatography. The objects of the study were solutions of “C5A”, “Maxoil D”, “Detersol”, polymethymethacrylate “D” (PMAD), “Keropur D ”, Antigel “Difron 3319” and “Superantigel” individual additives as well as the diesel fuel produced by the “Kuban Oil and Gas Company - Ilskiy Oil Refinery”, LLC. The conditions for chromatographic separation and determination of polymeric functional additives were determined considering the analyzed fuel matrix, the working range of the separated masses and molecular weights of analytes, and the composition of the eluent applicable for wide range of analytes. The chromatographic system was calibrated using the narrowly dispersed analytical standard polystyrene samples with molecular weights of 1000, 2000, 4000, 10000, 30,000, 50,000, and 70,000 Da respectively. The molecular weight characteristics were calculated for each functional additive from the analytical standard samples of polystyrene. The method of GPC determination of polymeric functional additives in diesel fuel, along with the concentration characteristics, also makes it possible to determine the molecular weight parameters of wide range of polymeric functional additives; therefore, it is promising for monitoring the quality of the diesel fuel. The proposed analytical scheme was tested in the analysis of real sample of diesel fuel. The GPC scheme for the determination of the “Keroflux 3699” depressant-dispersant additive in diesel fuel included sample preparation using the solid-phase extraction, calibration of the chromatographic system using the standard polystyrene samples, GPC determination of additive components, and the calculation of molecular weight characteristics. The molecular weight characteristics of the “Keroflux 3699” depressant dispersant additive in diesel fuel have been established - the number average and weight average molecular weights equivalent to polystyrene were 10,300 and 8800 Da respectively, and the polydispersity index of the additive was 1.17.

Thermomechanical Characterization of the Molecular Weight of Linear Polymers Exemplified by Natural Rubber

1964 ◽  
Vol 37 (1) ◽  
pp. 99-102
Author(s):  
B. Ya Teitelbaum ◽  
K. F. Gubanov
Keyword(s):  
Molecular Weight ◽  
Experimental Studies ◽  
Thermomechanical Properties ◽  
Linear Polymers ◽  
Molecular Weights ◽  
Calculated Molecular Weight ◽  
Low Degree ◽  
Wide Range ◽  
High Elasticity

Abstract In the previous work of Kargin and Slonimskii and that of Kargin and Sogolov who studied the behavior of polymers over a wide range of temperature, it was shown that the shape of thermomechanical curves depends on magnitude of molecular weight of the polymers. As a result of investigation of theory and actual experimental studies in which polyisobutylene was employed, it was demonstrated that molecular weight could be estimated on the basis of thermomechanical properties. This suggested a relationship between the magnitude of molecular weight M found from the thermomechanical curves and that which was determined from glass temperatures Tg and fluid temperatures Tf. For practical use of this relationship, it is necessary to know the magnitude of the segments and two empirical constants. These values can be found by calculation of molecular weights of three different fractions of the polymer. This can be accomplished experimentally by any independent method. Once these magnitudes are determined, it is necessary to find, by means of the thermomechanical curve, the values Tg and Tf, in order to calculate the molecular weight of any sample of the same polymer. Because of the low degree of accuracy of determination of these values, and because of the peculiar differences, the reliability of the calculated molecular weight cannot be great, especially since the equation utilizes the logarithm of the molecular weight figure and not the molecular weight itself. Apparently the graphic solution is simpler than analytical methods: by means of the data of thermomechanical studies for various fractions of known molecular weights it is possible to graph the dependence of M or log Mon Tf−Tg. From what has been said, it is evident that we may use the demonstrated method only for polymers of high elasticity, and furthermore, only for those fractions in which Tf−Tg is greater than zero.

scholarly journals SYNTHESIS OF POLYMERS BASED ON STEARYL METHACRYLATE AND THEIR USE AS ADDITIVES FOR DIESEL FUEL

2018 ◽  
Vol 61 (7) ◽  
pp. 83
Author(s):  
Ksenia Yu. Simanskaya ◽  
Ivan D. Grishin ◽  
Dmitry F. Grishin
Keyword(s):  
Molecular Weight ◽  
Low Temperature ◽  
Radical Polymerization ◽  
Diesel Fuel ◽  
Controlled Radical Polymerization ◽  
Polymerization Process ◽  
Methyl Amine ◽  
Molecular Weight Characteristics ◽  
Wide Range ◽  
Stearyl Methacrylate

In this article the features of controlled radical polymerization of stearyl methacrylate in the presence of copper-based compounds in combination with nitrogen-containing ligands such as tris[2-(dimethylamino)ethyl]amine and tris[(2-pyridyl)methyl]amine were studied. The ethyl 2-bromoisobutyrate was used as the initiator of the polymerization process. The synthesized polymers were characterized by gel permeation chromatography and MALDI-TOF time-of-flight mass spectrometry. It was found that the proposed catalytic systems allow conducting controlled radical polymerization of stearyl methacrylate according to the Atom Transfer Radical Polymerization mechanism at relatively mild temperature conditions. It was revealed that the nature of the organic ligand has a significant effect on the rate of polymerization and the molecular-weight characteristics of the synthesized samples. Using the copper(I) bromide catalytic system in combination with tris[(2-pyridyl)methyl]amine as a ligand at reagents molar ratio of 1:4, the polymerization of stearyl methacrylate proceeded with high reaction rate to deep conversions in a wide range of molecular weights. The observed linear growth of the molecular weight of the polymer with increasing conversion and low polydispersity index of the synthesized polymers being at the level of 1.19-1.29, considered as an evidence of the controlled mode of polymerization. The influence of the molecular weight characteristics of polymers based on stearyl methacrylate on the low-temperature properties of  diesel fuel of specification24-2000 produced by OOO «LUKOIL-Nizhegorodnefteorgsintez» was evaluated using a low-temperature analyzer MX-700 (PE-7200I) in accordance with the requirements of Russian (GOST 5066-91 and GOST 20287-91) and the international (ISO-3016) standards for the quality of petroleum products. It was established that the synthesized polymers can be used as additives that reduce the temperature range of solidification of environmentally clean diesel fuels, while the molecular weight of polystearyl methacrylate has a significant effect on the depressor properties of the fuel.Forcitation:Simanskaya K.Yu., Grishin I.D., Grishin D.F. Synthesis of polymers based on stearyl methacrylate and their use as additives for diesel fuel. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 7. P. 82-89

scholarly journals Recent Developments in the Determination of Biomarkers of Tobacco Smoke Exposure in Biological Specimens: A Review

2021 ◽  
Vol 18 (4) ◽  
pp. 1768
Author(s):  
Hernâni Marques ◽  
Pedro Cruz-Vicente ◽  
Tiago Rosado ◽  
Mário Barroso ◽  
Luís A. Passarinha ◽  
...  
Keyword(s):  
Tobacco Smoke ◽  
Solid Phase ◽  
Smoke Exposure ◽  
Tobacco Smoke Exposure ◽  
World Health ◽  
Second Hand Smoke ◽  
Tobacco Exposure ◽  
Wide Range ◽  
Recent Developments

Environmental tobacco smoke exposure (ETS) and smoking have been described as the most prevalent factors in the development of certain diseases worldwide. According to the World Health Organization, more than 8 million people die every year due to exposure to tobacco, around 7 million due to direct ETS and the remaining due to exposure to second-hand smoke. Both active and second-hand exposure can be measured and controlled using specific biomarkers of tobacco and its derivatives, allowing the development of more efficient public health policies. Exposure to these compounds can be measured using different methods (involving for instance liquid- or gas-chromatographic procedures) in a wide range of biological specimens to estimate the type and degree of tobacco exposure. In recent years, a lot of research has been carried out using different extraction methods and different analytical equipment; this way, liquid–liquid extraction, solid-phase extraction or even miniaturized procedures have been used, followed by chromatographic analysis coupled mainly to mass spectrometric detection. Through this type of methodologies, second-hand smokers can be distinguished from active smokers, and this is also valid for e-cigarettes and vapers, among others, using their specific biomarkers. This review will focus on recent developments in the determination of tobacco smoke biomarkers, including nicotine and other tobacco alkaloids, specific nitrosamines, polycyclic aromatic hydrocarbons, etc. The methods for their detection will be discussed in detail, as well as the potential use of threshold values to distinguish between types of exposure.

Determination of Bendiocarb Insecticide by Reverse Flow Injection Analysis Using a Solid-Phase Reactor Containing Micro PbO2, Nano PbO2 and Grafted SiO2 - PbO2 Immobilized

2020 ◽  
Vol 42 (1) ◽  
pp. 31-31
Author(s):  
Malik H Alaloosh Alamri Malik H Alaloosh Alamri ◽  
Sadeem Subhi Abed and Abdulkareem M A Alsammarraie Sadeem Subhi Abed and Abdulkareem M A Alsammarraie
Keyword(s):  
Flow Injection ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Reverse Flow ◽  
Blue Color ◽  
Wide Range ◽  
Solid Phase Reactor ◽  
Grafted Nanoparticles ◽  
Reverse Flow Injection

Bendiocarb (BEN) is an acutely toxic carbamate insecticide which used in public places and agriculture, it is also effective against a wide range of nuisance and disease vector insects. A new rapid and sensitive reverse flow injection spectrophotometric procedure coupled with on-line solid-phase reactor is designed in this article for the determination of BEN in its insecticidal formulations and water samples, by using three different solid-phase reactors containing bulk PbO2 (B-SPR), PbO2 nanoparticles (N-SPR) and grafted nanoparticles of SiO2-PbO2 (G-SPR) immobilized on cellulose acetate matrix (CA). This method of oxidative coupling is based on alkaline hydrolysis of the BEN pesticide, and then coupled with N,N dimethyl-p-phenylenediamine sulphate (DMPD) to give a blue color product which measured at λmax 675 nm. It worth to mentioned that under optimal conditions, Beer’s law is obeyed in the range of 1-175 μg mL-1 for B-SPR and 0.25-70 μg mL-1 of BEN for both N-SPR and G-SPR respectively within limit of detection (LOD) of 0.931, 0.234 and 0.210 μg mL-1 for B-SPR N-SPR and G-SPR respectively. The surface methodology of the solid phase was also investigated by using atomic force microscopy.

CATIONIC COPOLYMERIZATION OF ISOBUTYLENE WITH ISOPRENE: KINETICS OF THE PROCESS AND DETERMINATION OF KINETIC CONSTANTS

2015 ◽  
Vol 88 (4) ◽  
pp. 574-583 ◽  
Author(s):  
N. V. Ulitin ◽  
K. A. Tereshchenco ◽  
D. A. Shiyan ◽  
G. E. Zaikov
Keyword(s):  
Experimental Data ◽  
Molecular Weight ◽  
Cationic Polymerization ◽  
Methyl Chloride ◽  
Theoretical Description ◽  
Kinetic Constants ◽  
Molecular Weight Characteristics ◽  
Cationic Copolymerization ◽  
Kinetics Of

ABSTRACT A theoretical description has been developed of the kinetics of isobutylene with isoprene (IIR) cationic polymerization in the environment of methyl chloride on aluminum trichloride as the catalyst. Based on experimental data on the kinetics of copolymerization (isobutylene conversion curve) and the molecular weight characteristics of the copolymer of IIR, kinetic constants for the process were found. Adequacy of the developed theoretical description of the kinetics of the IIR copolymerization process was confirmed by comparing the experimental molecular-weight characteristics calculated by this description, independent characteristics, and IIR unsaturation.

EFFECTS OF FRESH PLASMA OR WHOLE BLOOD TRANSFUSIONS ON PATIENTS WITH VARIOUS TYPES OF MUCOPOLYSACCHARIDOSIS

PEDIATRICS ◽  
1972 ◽  
Vol 50 (5) ◽  
pp. 688-692
Author(s):  
Anatole S. Dekaban ◽  
Kenton R. Holden ◽  
George Constantopoulos
Keyword(s):  
Molecular Weight ◽  
Weight Distribution ◽  
Whole Blood ◽  
Blood Transfusions ◽  
Molecular Weights ◽  
The Third ◽  
Clinical Observations ◽  
Before And After ◽  
Fresh Plasma

Repeated fresh plasma or whole blood transfusions were given to five patients with either Hurler, Hunter, or Sanfilippo types of mucopolysaccharidosis. Clinical observations and total 24-hour urinary AMPS and their composition and molecular weight distribution were determined before, during, and after transfusions. The two patients who received plasma transfusions showed no noticeable change in the amount of AMPS excreted; of the three patients who received whole blood transfusions, two had slightly less excretion of AMPS while the third showed no difference. The AMPS in the CSF were measured in one patient before and after blood transfusions and found to be unchanged; likewise, the determination of molecular weights in the isolated AMPS was virtually identical. In the patients studied, the transfusions caused no demonstrable difference in the patients' clinical condition.

Determination of Ardacin in Various Silage Feed Diets by a Rapid Liquid Chromatographic Assay

1995 ◽  
Vol 78 (1) ◽  
pp. 16-21
Author(s):  
Sylvia V B Fagan ◽  
Connie Gombatz ◽  
Hafez Abdel-Kader ◽  
Govind Menon
Keyword(s):  
Mobile Phase ◽  
Solid Phase ◽  
Chromatographic System ◽  
Method Of Calculation ◽  
Feed Formulation ◽  
Sample Extract ◽  
Liquid Chromatographic ◽  
Solid Phase Extract ◽  
Cyano Column

Abstract A method is presented for the detection and quantitation of Ardacin in silage feed diets by liquid chromatography, using a cyano column and an acetonitrile–methanol water mobile phase modified with trifluoroacetic acid. This method includes comprehensive procedures for extracting Ardacin from various silage feed formulations, cleaning up the extracted sample by using solid-phase extractions, and analyzing the eluted solid-phase extract with a suitable liquid chromatographic system. Ardacin was extracted from the silage feed formulations with 50% acetonitrile and 50% 0.1 M KOH. The extract was cleaned up with a wide-pore butyl solidphase extraction cartridge. The sample extract was chromatographed and quantified at 220 nm, using an external method of calculation. Recoveries of the medicated silage feed formulation ranged from 72.1 ± 1.7% to 109.1 ± 2.4%, depending on the sites and types of formulation analyzed.

Molecular Weights and Intrinsic Viscosities of Polyisobutylenes

1943 ◽  
Vol 16 (3) ◽  
pp. 493-508
Author(s):  
Paul J. Flory
Keyword(s):  
Molecular Weight ◽  
Intrinsic Viscosity ◽  
Average Molecular Weight ◽  
Chain Structure ◽  
Molecular Weight Range ◽  
Molecular Weights ◽  
Satisfactory Precision ◽  
Heterogeneous Polymers ◽  
Definition Of

Abstract Experimental methods for fractionating polyisobutylene and for determining osmotic pressures have been described. The ratio π/c of osmotic pressure to concentration has been found in the case of cyclohexane solutions of polyisobutylene to vary nonlinearly with concentration, contrary to recent theories advanced by Huggins and the writer. The slope of this relationship appears to be independent of molecular weight. Reliable methods for extrapolating π/c to c=0 have been established, enabling the determination of absolute molecular weights with satisfactory precision up to values of about 1,000,000. Molecular weights of polyisobutylenes calculated from Staudinger's equation are too low; the discrepancy is more than ten-fold at high molecular weights. On the basis of data for carefully fractionated samples covering a two-hundred-fold molecular weight range, the intrinsic viscosity is found to be proportional to the 0.64 power of the molecular weight. This decided deviation from Staudinger's “law”cannot in this instance be attributed to nonlinear chain structure, as Staudinger has sought to do in other cases. This dependence of molecular weight on intrinsic viscosity leads to the definition of a “viscosity average”molecular weight which is obtained when the relationship is applied to heterogeneous polymers. The viscosity average is less than the weight average molecular weight, which would be obtained if Staudinger's equation were applicable, and greater than the number average obtained by osmotic or cryoscopic methods.

Measurement of the Isothermal Volume Dilation Accompanying the Unilateral Extension of Rubber

1959 ◽  
Vol 32 (2) ◽  
pp. 428-433
Author(s):  
Fred G. Hewitt ◽  
Robert L. Anthony
Keyword(s):  
Molecular Weight ◽  
Young’S Modulus ◽  
Experimental Results ◽  
Molecular Weights ◽  
Rubber Specimen ◽  
A Value ◽  
Fractional Increase ◽  
Internal Agreement ◽  
Good Agreement

Abstract The fractional increase in volume accompanying the isothermal extension of soft gum rubber was measured for four rubber samples at mean extensions of 14, 33, and 51%. The chain molecular weights Mc of the four samples were 5500, 5100, 4400, and 3000, with an estimated uncertainty of about 10% in each value of Mc. The observed fractional increase in volume ranged from 3.2×10−5 to 142×10−5, the latter value being observed for the sample of lowest chain molecular weight and at the extension of 51%. The experimental results for each sample have been represented by theoretical curves based on Gee's expression for the fractional increase in volume as a function of the sample extension. The theoretical curves exhibit good agreement with those of Gee, Stern, and Treloar. The process of fitting the theoretical curves to the experimental points constituted a determination of Young's modulus E for each rubber specimen. As a check on the experimental results, and also on the theory employed, determinations of E were also made by two additional methods, namely, from rough stess-strain curves, and from the relation E=3γρRT/Mc. With one exception, the internal agreement between the three determinations of E for the four different samples was satisfactory. The exception noted can probably be ascribed to the use of too small a value of Mc for the sample of lowest chain molecular weight.

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