Effect of Different Low-Molar Mass Electrolytes on the Viscometric Behaviour of Sodium Polystyrenesulfonate in Methanol-Water Mixed Solvent Media

Effluents of biological sewage treatment plants mainly contain non-biodegradable, polar, organic pollutants of biogenic and anthropogenic origin. This paper presents a substance-specific determination method for these compounds, which are partly able to reach drinking water during the soil filtration process. Tandem mass spectrometry (MS/MS) combined with softly ionizing interfaces is applied for this purpose. The behaviour of the functional groups of these pollutants - forming characteristic fragment ions under MS/MS conditions and abstracting neutral particles - is used for detection. With help from this screening process on specific functional groups it is possible to establish the presence of substance groups with similar behaviour in the aquatic environment. Additionally this analytical procedure provides information on the molar mass of the pollutants detected. In a second step the compounds characterized by the molar mass and belonging to a group of pollutants with specific functional groups can be identified using MS/MS.

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QELSS diffusion data for moderately broad molar mass distribution polymer samples compared with data from classical gradient techniques

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19891821 ◽

1989 ◽

Vol 54 (7) ◽

pp. 1821-1829

Author(s):

Bedřich Porsch ◽

Simon King ◽

Lars-Olof Sundelöf

Keyword(s):

Diffusion Coefficient ◽

Mass Distribution ◽

Molar Mass ◽

Molar Mass Distribution ◽

Diffusion Data ◽

Mass Distributions ◽

Classical Diffusion ◽

Polydisperse Polymer

The differences between the QELSS and classical diffusion coefficient of a polydisperse polymer resulting from distinct definitions of experimentally accessible average values are calculated for two assumed specific forms of molar mass distributions. Predicted deviations are compared with the experiment using NBS 706 standard polystyrene. QELSS Dz of this sample relates within 2-4% to the classical diffusion coefficient, if the Schulz-Zimm molar mass distribution is assumed to be valid. In general, differences between the height-area and QELSS diffusion coefficient of about 20% may be found for Mw/Mn ~ 2, and this value may increase above 35%, if strongly tailing molar mass distribution pertains to the sample.

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Study of Sedimentation Velocity of Block Copolymer Micelles

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19930071 ◽

1993 ◽

Vol 58 (1) ◽

pp. 71-76 ◽

Cited By ~ 3

Author(s):

Minmin Tian ◽

C. Ramireddy ◽

Stephen E. Webber ◽

Petr Munk

Keyword(s):

Block Copolymer ◽

Methacrylic Acid ◽

Mixed Solvent ◽

Hard Spheres ◽

Sedimentation Velocity ◽

Hydrodynamic Coefficient ◽

Block Copolymer Micelles ◽

Copolymer Micelles ◽

Size Heterogeneity ◽

Good Agreement

No anomalies were observed during the measurement of sedimentation coefficients of block copolymer micelles formed by copolymers of styrene and methacrylic acid in a mixed solvent; 80 vol.% of dioxane and 20 vol.% of water. The shapes of the sedimenting boundaries suggest that the size heterogeneity of the micelles is small. Linear relations between 1/s and c were obtained. The value of the hydrodynamic coefficient κ was between 2 and 4 in a good agreement with the value 2.75 or 2.86 that was obtained by combining Burgers' or Fixman's values of the coefficient of the concentration dependence kvs for hard spheres with Einstein's value of [η] for spheres.

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Activities of Components in the Ca2MgSi2O7-CaSiO3Molten System

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19960837 ◽

1996 ◽

Vol 61 (6) ◽

pp. 837-843

Author(s):

Ladislav Kosa ◽

Ivan Nerád ◽

Katarína Adamkovičová ◽

Jozef Strečko ◽

Ivo Proks

Keyword(s):

Gibbs Energy ◽

Molar Mass ◽

Excess Entropy ◽

Enthalpy Of Mixing ◽

Real Particle ◽

Entropy Of Mixing ◽

Energy Of Mixing ◽

Gibbs Energy Of Mixing

Activities of the components, the Gibbs energy of mixing, and the excess entropy of mixing have been calculated for the Ca2MgSi2O7-CaSiO3 system. The mole fractions of the components were calculated assuming that in the point of the formal component Ca2MgSi2O7, the molar mass of the quasi-real particle in the melt corresponds to its formula molar mass, whereas in the point of the formal component CaSiO3 the molar mass of the quasi-real particle in the melt is 8.5 times higher than as corresponds to its formula. The fact that the enthalpy of mixing is zero whereas the excess entropy of mixing is non-zero suggests that Ca2MgSi2O7-CaSiO3 melts behave as athermal solutions.

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Development and Characterization of Amine-Clay Hybrid Adsorbents for CO2 Capture

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1133.547 ◽

2016 ◽

Vol 1133 ◽

pp. 547-551 ◽

Cited By ~ 2

Author(s):

Ali E.I. Elkhalifah ◽

Mohammad Azmi Bustam ◽

Azmi Mohd Shariff ◽

Sami Ullah ◽

Nadia Riaz ◽

...

Keyword(s):

Adsorption Capacity ◽

Surface Area ◽

Surface Properties ◽

Molar Mass ◽

Adsorption Ability ◽

Stepwise Increase ◽

Inverse Effect ◽

Bet Method ◽

Sodium Form

The present work aims at a better understanding of the influences of the intercalated mono-, di- and triethanolamines on the characteristics and CO2 adsorption ability of sodium form of bentonite (Na-bentonite). The results revealed that the molar mass of intercalated amines significantly influenced the structural and surface properties as well as the CO2 adsorption capacity of Na-bentonite. In this respect, a stepwise increase in the d-spacing of Na-bentonite with the molar mass of amine was recorded by XRD technique. However, an inverse effect of the molar mass of amine on the surface area was confirmed by BET method. CO2 adsorption experiments on amine-bentonite hybrid adsorbents showed that the CO2 adsorption capacity inversly related to the molar mass of amine at 25 ͦC and 101 kPa. Accordingly, Na-bentonite modified by monoethanolammonium cations adsorbed as high as 0.475 mmol CO2/g compared to 0.148 and 0.087 mmol CO2/g for that one treated with di- and triethanolammonium cations, respectively.

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Highly Efficient MOF Catalyst Systems for CO2 Conversion to Bis-Cyclic Carbonates as Building Blocks for NIPHUs (Non-Isocyanate Polyhydroxyurethanes) Synthesis

Catalysts ◽

10.3390/catal11050628 ◽

2021 ◽

Vol 11 (5) ◽

pp. 628

Author(s):

Adolfo Benedito ◽

Eider Acarreta ◽

Enrique Giménez

Keyword(s):

Molar Mass ◽

Cycloaddition Reaction ◽

Building Blocks ◽

Catalyst System ◽

Cyclic Carbonate ◽

Ammonium Bromide ◽

Cyclic Carbonates ◽

High Molar Mass ◽

Highly Efficient ◽

Free Process

The present paper describes a greener sustainable route toward the synthesis of NIPHUs. We report a highly efficient solvent-free process to produce [4,4′-bi(1,3-dioxolane)]-2,2′-dione (BDC), involving CO2, as renewable feedstock, and bis-epoxide (1,3-butadiendiepoxide) using only metal–organic frameworks (MOFs) as catalysts and cetyltrimethyl-ammonium bromide (CTAB) as a co-catalyst. This synthetic procedure is evaluated in the context of reducing global emissions of waste CO2 and converting CO2 into useful chemical feedstocks. The reaction was carried out in a pressurized reactor at pressures of 30 bars and controlled temperatures of around 120–130 °C. This study examines how reaction parameters such as catalyst used, temperature, or reaction time can influence the molar mass, yield, or reactivity of BDC. High BDC reactivity is essential for producing high molar mass linear non-isocyanate polyhydroxyurethane (NIPHU) via melt-phase polyaddition with aliphatic diamines. The optimized Al-OH-fumarate catalyst system described in this paper exhibited a 78% GC-MS conversion for the desired cyclic carbonates, in the absence of a solvent and a 50 wt % chemically fixed CO2. The cycloaddition reaction could also be carried out in the absence of CTAB, although lower cyclic carbonate yields were observed.

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