Search results for "solubility"

On the Correlations Between Constitution and Scintillation Properties in the p-Oligophenylene Series

1968

Abstract The paper deals with the problem: What properties are requested from an organic scintillator solute and what structural principles are given to realize, or at least to influence them especially by looking at the p-oligophenylene series? According to their importance and also in respect to more or less special purposes one can distinguish the following sequence: 1) An organic scintillator solute must have a sufficient solubility in all types of solvents used for this counting method. As a result of extensive systematic studies substitution of larger alkyl groups has been recognized as a very effective principle of solubilization. By use of branched, particularly long-chain branched …

Conformational preferences of side-chain protected amino acid residues and their impact in peptide synthesis

1983

Using the host-guest technique, tentative scales for the helix-inducing power and the β-structure-forming potential of various side-chain protected amino acid residues in trifluoro-ethanol are established mainly by CD measurements. The generally lower tendency for β-structure formation of the host–guest peptides compared to that of the host peptide is discussed. The influence of these conformational features on the solubility of the peptides is also pointed out.

Synthesis of new polymers via Diels–Alder reaction. III. Biscyclohexadienephthalimides as dienes

1993

Difunctional cyclohexadienes with dihydrophthalimide central unitsand phenyl side groups to increase solubility are used as bisdienes in repetitive Diels-Alder polyadditions with bis(4-(1,2,4,-triazoline-3,5-dione-4-yl)phenyl)methane as a difunctional dienophile. The polymers show good solubility in CH 2 Cl 2 and CHCl 3 . Non-stoichiometric Diels-Alder polyaddition with slight excess of the bistriazolinedione provides the possibility of synthesizing telechelics with highly reactive triazolinedione end groups

Alkyl and diether bridged N,N,N′,N′-tetra(2-hydroxybenzyl)diamines: effects of hydrogen bonding on structure and solubility

2012

A solvent-free one-step method has been used to prepare two N,N,N′,N′-tetra(2-hydroxy-3,5-dimethylbenzyl)diaminoalkanes containing a long n-alkyl bridge (6 and 8 CH2 groups between N-atoms). In addition, three novel N,N,N′,N′-tetra(2-hydroxy-5-alkyl-3-alkylbenzyl)-diaminoalkane-ethers (alkyl = methyl or t-butyl) have been prepared using the same method. The compounds were studied in the solid state using single crystal X-ray diffraction and their solubility was studied using UV/Vis spectroscopy. In the solid state, hydrogen bonding plays a key role in controlling the crystal packing and conformations of the molecules, thus affecting the solubility and properties of the compounds.

Polymer Retention Mechanism in GPC on Active Gels

1980

Abstract The elution behaviour of low molecular weight polystyrene (PS) down to the monomer on spherosil gel in several eluents has been studied. In the medium range of molecular weights the elution behaviour is similar to that followed by high molecular weight PS, the differences in elution volumes among different eluents increasing monotonically with decreasing molecular weight and partition rather than adsorption probably being responsible for the shifts in retention volumes. However, at the total permeation limit, the situation is alike to that found in liquid-solid chromatography, the elution volumes of solutes with molecular sizes very close to that of styrene being determined by solv…

1993

Several zwitterionic polymers were prepared by radical homopolymerization of surfactant monomers which bear diallyl, diene or vinylcyclopropane moieties. These polymer systems were complemented by alternating copolymers of appropriate zwitterionic vinyl compounds. Thus, polymers with reduced (as compared with simple vinylic homopolymers, or statistical copolymers) and well defined density of surfactant side groups are obtained. The solubilities found for these polymers are dominated by polymer geometry rather than by the balance of hydrophilic and hydrophobic fragments, thus corroborating a “main-chain spacer” model proposed recently. All water-soluble polymers exhibit characteristic featur…

1992

A series of copolymers are synthesized by repetitive Diels-Alder polyaddition reaction of bifunctional cyclohepta-1,3,5-trienes with bifunctional 1,2,4-triazoline-3,5-diones. The copolymers of different bistriazolinediones with a bisdiene, or of different biscycloheptatrienes with a dienophile, have good solubility in CH2Cl2 and CHCl3, while the homopolymers are poorly soluble. The copolymers were characterized by standard analytical techniques to test the structural regularity of these systems. Due to the kinetic control, it is possible to apply copolymerization statistics to these systems. Based on a model study, it is concluded that alipatic and aromatic bistriazolinediones have the same…

Erweiterte Konjugation in unsymmetrischen Stilbenylsquarainen

1998

Extended Conjugation in Stilbenylsquaraines Unsymmetrical 1-aryl-3-stilbenylsquaraines 2a–e and 1,3-bis(stilbenyl)squaraines 3a–c were prepared by CC coupling reactions of the corresponding substituted arenes with derivatives of squaric acid (Schemes 2 and 3). Dialkylamino and alkoxy groups enhance the solubility of these dyes and enlarge the intramolecular charge transfer of these donor–acceptor–donor systems. The extended conjugation of the stilbene units – in comparison with arene building blocks – leads to significant bathochromic shifts in the Vis/NIR absorption spectra.

Versuche über die oxydation von polyacroleinen mit wasserstoffperoxyd und peressigsäure. Polymer acroleine. 8. Mitt.

1958

Polyacroleine werden durch verdunntes Wasserstoffperoxyd vollstandig abgebaut. Als Abbauprodukte konnten Kohlendioxyd, Ameisensaure und Essigsaure identifiziert werden. Daneben bilden sich noch unbekannte nicht-fluchtige Saren. Polyacrylsaure erleidet unter den gleichen Bedingungen ebenfalls einen Abbau. Die Zusammensetzung der Abbauprodukte ist eine andere. Durch Peressigsaure werden Polyacroleine zu polymeren Sauren oxydiert. Diese gleichen bezuglich der Loslichkeit, der Reaktionen mit Schwermetallsalzen und dem IR- Spektrum weitgehend der Polyacrylsaure. Polyacroleins are completely degraded by the action of dilute hydrogen peroxide. Among the products of degradation carbon dioxyde, form…

Der Verteilungsraum von physikalisch gelöstem Sauerstoff in wäßrigen Lösungen organischer Substanzen / The Distribution Space of Physically Dissolved…

1976

Abstract In order to evaluate the distribution of molecular oxygen in biological systems, the oxygen solubility (ml/ml atm) at 37 °C in aqueous solutions of thirty organic substances with different concentrations was measured by the classical Van Slyke principle. The oxygen solubility always (with the exception of hemoglobin) decreases exponentially with increasing concentration of the respective substance. In all cases this behavior is described highly significant by a simple empiric exponential function, when the substance concentration as well as the oxygen solubility of pure water is given. The influence of one substance on oxygen solubility contributes additively to the over-all solubi…