scholarly journals Polyesters on the basis of petroleum resin and polyethylene glycols

2007 ◽  
Vol 1 (3) ◽  
pp. 155-160
Author(s):  
Witold Brostow ◽  
◽  
Michael Bratychak ◽  
Dorota Pietkiewicz ◽  
Petro Topilnytsky ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Polyethylene Glycols ◽  
Carboxyl Groups ◽  
Optimal Temperature ◽  
Equimolar Ratio ◽  
Average Molecular Mass ◽  
Formation Reaction ◽  
Chain Molecules ◽  
Petroleum Resin ◽  
Optimal Temperature Range

New polyesters have been obtained on the basis of C9 petroleum resin with carboxyl groups and polyethylene glycols. The average molecular mass of the petroleum resin is 1050, its functionality = 1.74. Optimal for the polyesters synthesis is the equimolar ratio between the initial compounds. The reaction is performed in the melt in the presence of p-toluenosulphuric acid as the catalyst. In the optimal temperature range 150 - 190oC the yield of the process ranges from 91 to 94 % depending on the conditions. The rate of the polyester formation reaction practically does not depend on the length of the acids or the alcohol chain molecules. The functionality is the decisive factor. We report the degrees of polycondensation of the new polyesters.

Extraction of polyethylene glycols with dicarbolide solutions in nitrobenzene

1990 ◽  
Vol 55 (8) ◽  
pp. 1959-1967 ◽  
Author(s):  
Petr Vaňura ◽  
Pavel Selucký
Keyword(s):  
Polyethylene Glycol ◽  
Molecular Mass ◽  
Extraction Constant ◽  
Metal Extraction ◽  
Polyethylene Glycols ◽  
Relative Molecular Mass ◽  
Published Data ◽  
Average Molecular Mass ◽  
Peg 400 ◽  
Extraction Constants

The extraction of polyethylene glycol of average molecular mass 400 (PEG 400) with dicarbolide solution in nitrobenzene and of longer-chain polyethylene glycol, of average molecular mass 1 500 (PEG 1 500), with chlorinated dicarbolide solution in nitrobenzene was studied. During the extraction of PEG 400, the polyethylene glycol solvates the Horg+ ion in the organic phase giving rise to the HLorg+ species (L is polyethylene glycol). The obtained value of the extraction constant Kex(HLorg+) = 933 is consistent with published data of metal extraction. Extraction of PEG 1 500 was treated applying the simplified assumption that the thermodynamic behaviour of PEG 1 500 is the same as that of n molecules of polyethylene glycol with relative molecular mass 1 500/n, each solvating one cation. For this model, the value of n = 3.2 ± 1.1 and the values of the extraction constants of the HL1/n,org+ and HL2/n,org+ species were obtained by using the adapted program LETAGROP. This value of n is consistent with published extraction data in the presence of polyethylene glycol with a relative molecular mass from 200 to 1 000.

scholarly journals How many carboxyl groups does an average molecule of humic-like substances contain?

2008 ◽  
Vol 8 (3) ◽  
pp. 10005-10020 ◽  
Author(s):  
I. Salma ◽  
G. G. Láng
Keyword(s):  
Molecular Mass ◽  
Group Analysis ◽  
Weak Acid ◽  
Biologically Active ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Average Molecular Mass ◽  
Solubility In Water ◽  
Functional Group Analysis ◽  
The Mean

Abstract. The carboxyl groups of atmospheric humic-like substances (HULIS) are of special interest because they influence the solubility in water, affect the water activity and surface tension of droplets in the air, and allow formation of chelates with biologically active elements. Experimentally determined abundances of the carboxyl group within HULIS by functional group analysis are consistent with our knowledge on the average molecular mass of HULIS if the number of dissociable carboxyl groups is assumed to be rather small. The best agreement between the average molecular mass derived from the existing abundance data and the average molecular mass published earlier occurs for assuming approximately one dissociable carboxyl group only. This implies that HULIS can not be regarded as polycarboxilic acid. The average molecular mass of HULIS derived from our electrochemical measurements with the assumption of one dissociable carboxyl group per molecule ranges from 248 to 305 Da. It was concluded that HULIS are a moderately strong/weak acid with a dissociation constant of about pK=3.4, which fits well into the interval represented by fulvic and humic acids. The mean number of dissociable carboxyl groups in HULIS molecules was refined to be between 1.1 and 1.4.

scholarly journals How many carboxyl groups does an average molecule of humic-like substances contain?

2008 ◽  
Vol 8 (20) ◽  
pp. 5997-6002 ◽  
Author(s):  
I. Salma ◽  
G. G. Láng
Keyword(s):  
Molecular Mass ◽  
Group Analysis ◽  
Weak Acid ◽  
Biologically Active ◽  
Carboxyl Groups ◽  
Carboxyl Group ◽  
Average Molecular Mass ◽  
Solubility In Water ◽  
Functional Group Analysis ◽  
The Mean

Abstract. The carboxyl groups of atmospheric humic-like substances (HULIS) are of special interest because they influence the solubility in water, affect the water activity and surface tension of droplets in the air, and allow formation of chelates with biologically active elements. Experimentally determined abundances of the carboxyl group within HULIS by functional group analysis are consistent with our knowledge on the average molecular mass of HULIS if the number of dissociable carboxyl groups is assumed to be rather small. The best agreement between the average molecular mass derived from the existing abundance data and the average molecular mass published earlier occurs for assuming approximately one dissociable carboxyl group only. This implies that HULIS can not be regarded as polycarboxilic acid in diluted solutions. The average molecular mass of HULIS derived from our electrochemical measurements with the assumption of one dissociable carboxyl group or equivalently, one dissociable sulphate ester per molecule ranges from 250 to 310 Da. It was concluded that HULIS are a moderately strong/weak acid with a dissociation constant of about pK=3.4, which fits well into the interval represented by fulvic and humic acids. The mean number of dissociable hydrogen (i.e. of carboxyl groups and sulphate esters jointly) in HULIS molecules was refined to be between 1.1 and 1.4 in acidic solutions.

scholarly journals Nanomechanical Molecular Mass Sensing Using Suspended Microchannel Resonators

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3337
Author(s):  
Alberto Martín-Pérez ◽  
Daniel Ramos ◽  
Javier Tamayo ◽  
Montserrat Calleja
Keyword(s):  
Molecular Mass ◽  
Mass Density ◽  
Applied Pressure ◽  
Atomic Mass ◽  
Liquid Sample ◽  
Mass Sensing ◽  
Average Molecular Mass ◽  
Fluid Properties ◽  
Molecular Masses ◽  
Microchannel Resonators

In this work we study the different phenomena taking place when a hydrostatic pressure is applied in the inner fluid of a suspended microchannel resonator. Additionally to pressure-induced stiffness terms, we have theoretically predicted and experimentally demonstrated that the pressure also induces mass effects which depend on both the applied pressure and the fluid properties. We have used these phenomena to characterize the frequency response of the device as a function of the fluid compressibility and molecular masses of different fluids ranging from liquids to gases. The proposed device in this work can measure the mass density of an unknown liquid sample with a resolution of 0.7 µg/mL and perform gas mixtures characterization by measuring its average molecular mass with a resolution of 0.01 atomic mass units.

scholarly journals Levan-Producing Leuconostoc citreum Strain BD1707 and Its Growth in Tomato Juice Supplemented with Sucrose

2015 ◽  
Vol 82 (5) ◽  
pp. 1383-1390 ◽  
Author(s):  
Jin Han ◽  
Xiaofen Xu ◽  
Caixia Gao ◽  
Zhenmin Liu ◽  
Zhengjun Wu
Keyword(s):  
Molecular Mass ◽  
Sugar Content ◽  
Carbon Sources ◽  
Viable Cell ◽  
Monosaccharide Composition ◽  
Tomato Juice ◽  
Average Molecular Mass ◽  
Content Type ◽  
Leuconostoc Citreum ◽  
Sucrose Medium

ABSTRACTA levan-producing strain, BD1707, was isolated from Tibetan kefir and identified asLeuconostoc citreum. The effects of carbon sources on the growth ofL. citreumBD1707 and levan production in tomato juice were measured. The changes in pH, viable cell count, sugar content, and levan yield in the cultured tomato juice supplemented with 15% (wt/vol) sucrose were also assayed.L. citreumBD1707 could synthesize more than 28 g/liter of levan in the tomato juice-sucrose medium when cultured at 30°C for 96 h. Based on the monosaccharide composition, molecular mass distribution, Fourier transform infrared (FTIR) spectra, and nuclear magnetic resonance (NMR) spectra, the levan synthesized byL. citreumBD1707 was composed of a linear backbone consisting of consecutive β-(2→6) linkedd-fructofuranosyl units, with an estimated average molecular mass of 4.3 × 106Da.

Effects of temperature on growth of north-east Pacific moon jellyfish ephyrae, Aurelia labiata (Cnidaria: Scyphozoa)

2005 ◽  
Vol 85 (3) ◽  
pp. 569-573 ◽  
Author(s):  
Chad L. Widmer
Keyword(s):  
Good Condition ◽  
Bell Diameter ◽  
Optimal Temperature ◽  
Moon Jellyfish ◽  
Poor Condition ◽  
Temperature Range ◽  
North East ◽  
East Pacific ◽  
Optimal Temperature Range ◽  
Effects Of Temperature

The effects of ten different water temperatures on the growth of newly released ephyrae of Aurelia labiata were explored. Ephyrae grown at 21°C showed the greatest growth, increasing in bell diameter from about 4.0 mm to 14.5 mm in 14 days and remained in good condition for the duration of the experiment. Ephyrae subjected to other temperatures grew at different rates. Ephyrae maintained at 8°C gradually decreased in size during the experiment, shrinking in bell diameter from about 4.0 mm to 3.8 mm by day 14, but remained in apparent good condition. Ephyrae reared at 22.5°C and above everted their bells, were in poor condition, and were unable to feed or swim effectively by about day ten. In this study the optimal temperature range for rearing A. labiata ephyrae was 12°C—21°C, which corresponds with the reported range for this species.

Photo-Degradation Alkali Lignin by Bis-(2-Methyl Quinoline) Squarylium Cyanine TiO2 Photocatalyst in Sunlight

2013 ◽  
Vol 838-841 ◽  
pp. 2717-2720
Author(s):  
Y. L. Ma ◽  
Shi Xue Ren ◽  
Shi Yan Han
Keyword(s):  
Solar Energy ◽  
Energy Conversion ◽  
Molecular Mass ◽  
Energy Conversion Efficiency ◽  
Average Molecular Mass ◽  
Photo Degradation ◽  
Alkali Lignin ◽  
Squaraine Dye ◽  
Solar Energy Conversion Efficiency ◽  
Alcoholic Hydroxyl

Photo-degradation alkali lignin was prepared in sunlight by the system of TiO2 and squaraine dye (QSC). The influence of the ratio of QSC to TiO2 on the solar energy conversion efficiency was tested; the principle of degradation alkali lignin by TiO2 photocatalyst in sunlight was researched. The results showed that the number-average and mass-average molecular mass of degradation alkali lignin and the control lignin were 1,548 and 2,822, respectively, the phenolic hydroxyl of degradation alkali lignin is 5.63% with the control is 4.64%, and alcoholic hydroxyl of degradation alkali lignin is 3.21% with the control is 3.77%.

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